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Billings A, Kaiser C, Young CM, Hiebert LS, Cole E, Wagner JKS and Van Dover CL (2017), "SyPRID sampler: A large-volume, high-resolution, autonomous, deep-ocean precision plankton sampling system", Deep Sea Research Part II: Topical Studies in Oceanography. Vol. 137, pp. 297-306.
Abstract: The current standard for large-volume (thousands of cubic meters) zooplankton sampling in the deep sea is the MOCNESS, a system of multiple opening–closing nets, typically lowered to within 50 m of the seabed and towed obliquely to the surface to obtain low-spatial-resolution samples that integrate across 10 s of meters of water depth. The SyPRID (Sentry Precision Robotic Impeller Driven) sampler is an innovative, deep-rated (6000 m) plankton sampler that partners with the Sentry Autonomous Underwater Vehicle (AUV) to obtain paired, large-volume plankton samples at specified depths and survey lines to within 1.5 m of the seabed and with simultaneous collection of sensor data. SyPRID uses a perforated Ultra-High-Molecular-Weight (UHMW) plastic tube to support a fine mesh net within an outer carbon composite tube (tube-within-a-tube design), with an axial flow pump located aft of the capture filter. The pump facilitates flow through the system and reduces or possibly eliminates the bow wave at the mouth opening. The cod end, a hollow truncated cone, is also made of UHMW plastic and includes a collection volume designed to provide an area where zooplankton can collect, out of the high flow region. SyPRID attaches as a saddle-pack to the Sentry vehicle. Sentry itself is configured with a flight control system that enables autonomous survey paths to low altitudes. In its verification deployment at the Blake Ridge Seep (2160 m) on the US Atlantic Margin, SyPRID was operated for 6 h at an altitude of 5 m. It recovered plankton samples, including delicate living larvae, from the near-bottom stratum that is seldom sampled by a typical MOCNESS tow. The prototype SyPRID and its next generations will enable studies of plankton or other particulate distributions associated with localized physico-chemical strata in the water column or above patchy habitats on the seafloor.
BibTeX:
@article{Billings2017,
  author = {Billings, A and Kaiser, C and Young, C M and Hiebert, L S and Cole, E and Wagner, J K S and Van Dover, C L},
  title = {SyPRID sampler: A large-volume, high-resolution, autonomous, deep-ocean precision plankton sampling system},
  journal = {Deep Sea Research Part II: Topical Studies in Oceanography},
  year = {2017},
  volume = {137},
  pages = {297--306},
  doi = {10.1016/j.dsr2.2016.05.007}
}
Bourque JR, Robertson CM, Brooke S and Demopoulos AWJ (2017), "Macrofaunal communities associated with chemosynthetic habitats from the U.S. Atlantic margin: A comparison among depth and habitat types", Deep Sea Research Part II: Topical Studies in Oceanography. Vol. 137, pp. 42-55.
Abstract: Hydrocarbon seeps support distinct benthic communities capable of tolerating extreme environmental conditions and utilizing reduced chemical compounds for nutrition. In recent years, several locations of methane seepage have been mapped along the U.S. Atlantic continental slope. In 2012 and 2013, two newly discovered seeps were investigated in this region: a shallow site near Baltimore Canyon (BCS, 366–412 m) and a deep site near Norfolk Canyon (NCS, 1467–1602 m), with both sites containing extensive chemosynthetic mussel bed and microbial mat habitats. Sediment push cores, suction samples, and Ekman box cores were collected to quantify the abundance, diversity, and community structure of benthic macrofauna (textgreater300 μm) in mussel beds, mats, and slope habitats at both sites. Community data from the deep site were also assessed in relation to the associated sediment environment (organic carbon and nitrogen, stable carbon and nitrogen isotopes, grain size, and depth). Infaunal assemblages and densities differed both between depths and among habitat types. Macrofaunal densities in microbial mats were four times greater than those present in mussel beds and slope sediments and were dominated by the annelid families Dorvilleidae, Capitellidae, and Tubificidae, while mussel habitats had higher proportions of crustaceans. Diversity was lower in BCS microbial mat habitats, but higher in mussel and slope sediments compared to NCS habitats. Multivariate statistical analysis revealed specific sediment properties as important for distinguishing the macrofaunal communities, including larger grain sizes present within NCS microbial mat habitats and depleted stable carbon isotopes (δ13C) in sediments present at mussel beds. These results suggest that habitat differences in the quality and source of organic matter are driving the observed patterns in the infaunal assemblages, including high β diversity and high variability in the macrofaunal community composition. This study is the first investigation of seep infauna along the U.S. Atlantic slope north of the Blake Ridge Diapir and provides a baseline for future regional comparisons to other seep habitats along the Atlantic margin.
BibTeX:
@article{Bourque2017,
  author = {Bourque, J R and Robertson, C M and Brooke, S and Demopoulos, A W J},
  title = {Macrofaunal communities associated with chemosynthetic habitats from the U.S. Atlantic margin: A comparison among depth and habitat types},
  journal = {Deep Sea Research Part II: Topical Studies in Oceanography},
  year = {2017},
  volume = {137},
  pages = {42--55},
  doi = {10.1016/j.dsr2.2016.04.012}
}
Brooke SD, Watts MW, Heil AD, Rhode M, Mienis F, Duineveld GCA, Davies AJ and Ross SW (2017), "Distributions and habitat associations of deep-water corals in Norfolk and Baltimore Canyons, Mid-Atlantic Bight, USA", Deep Sea Research Part II: Topical Studies in Oceanography. Vol. 137, pp. 131-147.
Abstract: A multi-disciplinary study of two major submarine canyons, Baltimore Canyon and Norfolk Canyon, off the US mid-Atlantic coast focused on the ecology and biology of canyon habitats, particularly those supporting deep-sea corals. Historical data on deep-sea corals from these canyons were sparse with less than 750 records for the mid-Atlantic region, with most being soft sediment species. This study substantially increased the number of deep-sea coral records for the target canyons and the region. Large gorgonians were the dominant structure-forming coral taxa on exposed hard substrates, but several species of scleractinians were also documented, including first observations of Lophelia pertusa in the mid-Atlantic Bight region. Coral distribution varied within and between the two canyons, with greater abundance of the octocoral Paragorgia arborea in Baltimore Canyon, and higher occurrence of stony corals in Norfolk Canyon; these observations reflect the differences in environmental conditions, particularly turbidity, between the canyons. Some species have a wide distribution (e.g., P. arborea, Primnoa resedaeformis, Anthothela grandiflora), while others are limited to certain habitat types and/or depth zones (e.g., Paramuricea placomus, L. pertusa, Solenosmilia variabilis). The distribution of a species is driven by a combination of factors, which include availability of appropriate physical structure and environmental conditions. Although the diversity of the structure-forming corals (gorgonians, branching scleractinians and large anemones) was low, many areas of both canyons supported high coral abundance and a diverse coral-associated community. The canyons provide suitable habitat for the development of deep-sea coral communities that is not readily available elsewhere on the sedimented shelf and slope of the Mid-Atlantic Bight.
BibTeX:
@article{Brooke2017,
  author = {Brooke, S D and Watts, M W and Heil, A D and Rhode, M and Mienis, F and Duineveld, G C A and Davies, A J and Ross, S W},
  title = {Distributions and habitat associations of deep-water corals in Norfolk and Baltimore Canyons, Mid-Atlantic Bight, USA},
  journal = {Deep Sea Research Part II: Topical Studies in Oceanography},
  year = {2017},
  volume = {137},
  pages = {131--147},
  doi = {10.1016/j.dsr2.2016.05.008}
}
Hansman RL, Thurber AR, Levin LA and Aluwihare LI (2017), "Methane fates in the benthos and water column at cold seep sites along the continental margin of Central and North America", Deep Sea Research Part I: Oceanographic Research Papers. Vol. 120, pp. 122-131.
Abstract: The potential influence of methane seeps on carbon cycling is a key question for global assessments, but the study of carbon cycling in surface sediments and the water column of cold seep environments is complicated by the high temporal and spatial variability of fluid and gas fluxes at these sites. In this study we directly examined carbon sources supporting benthic and planktonic food webs at venting methane seeps using isotopic and molecular approaches that integrate this variability. At four seep environments located along North and Central America, microorganisms from two size fractions were collected over several days from 2800 to 9050 l of seawater to provide a time-integrated measure of key microbial groups and the carbon sources supporting the overall planktonic microbial community. In addition to water column measurements, the extent of seafloor methane release was estimated at two of the sites by examining the stable carbon isotopic signature (δ13C) of benthic metazoan infauna. This signature reveals carbon sources fueling the base of the food chain and thus provides a metric that represents a time-integrated view of the dominant microbial processes within the sediment. The stable carbon isotopic composition of microbial DNA (δ13C-DNA), which had values between −17.0 and −19.5‰, indicated that bulk planktonic microbial production was not ultimately linked to methane or other 13C-depleted seep-derived carbon sources. Instead these data support the importance of organic carbon derived from either photo- or chemoautotrophic CO2 fixation to the planktonic food web. Results of qPCR of microbial DNA sequences coding for a subunit of the particulate methane monooxygenase gene (pmoA) showed that only a small percentage of the planktonic microbial community were potential methane oxidizers possessing pmoA (textless5% of 16S rRNA gene copies). There was an overall decrease of 13C-depleted carbon fueling the benthic metazoan community from 3 to 5 cm below the seafloor to the sediment surface, reflecting limited use of isotopically depleted carbon at the sediment surface. Rare methane emission as indicated by limited aerobic methane oxidation acts to corroborate our findings for the planktonic microbial community.
BibTeX:
@article{Hansman2017,
  author = {Hansman, R L and Thurber, A R and Levin, L A and Aluwihare, L I},
  title = {Methane fates in the benthos and water column at cold seep sites along the continental margin of Central and North America},
  journal = {Deep Sea Research Part I: Oceanographic Research Papers},
  year = {2017},
  volume = {120},
  pages = {122--131},
  doi = {10.1016/j.dsr.2016.12.016}
}
Scott JJ, Glazer BT and Emerson D (2017), "Bringing microbial diversity into focus: high-resolution analysis of iron mats from the L''ihi Seamount", ENVIRONMENTAL MICROBIOLOGY., jan, 2017. Vol. 19(1), pp. 301-316.
Abstract: Thirty kilometers south of the island of Hawaii lies the Lihi Seamount, an active submarine volcano that hosts a network of low-temperature hydrothermal vents enriched in ferrous iron that supports extensive microbial mats. These mats, which can be a half a meter deep, are composed of ferric iron bound to organic polymers - the metabolic byproduct of iron-oxidizing Zetaproteobacteria. Though the role of Zetaproteobacteria in mat formation is well established, we have a limited understanding of how differences in diversity are related to mat morphology. We used Minimum Entropy Decomposition and ZetaOtu classification to demonstrate cryptic diversity between closely related Zetaproteobacteria while showing habitat and geographic specificity. Veiled mats, common structures at Lihi, exhibit distinct community composition and contain diversity not detected in other mat types, including specific Zetaproteobacteria and an unclassified Gammaproteobacteria. Our analyses also indicate that diversity can change dramatically across small spatial transects from points of active venting, yet we found comparatively few differences between major sampling sites. This study provides a better picture of the microbiome responsible for iron mat production at Lihi and has broad implications for our understanding of these globally distributed communities.
BibTeX:
@article{ISI:000393587200032,
  author = {Scott, Jarrod J and Glazer, Brian T and Emerson, David},
  title = {Bringing microbial diversity into focus: high-resolution analysis of iron mats from the L''ihi Seamount},
  journal = {ENVIRONMENTAL MICROBIOLOGY},
  year = {2017},
  volume = {19},
  number = {1},
  pages = {301--316},
  doi = {10.1111/1462-2920.13607}
}
Szitkar F, Tivey MA, Kelley DS, Karson JA, Fruh-Green GL and Denny AR (2017), "Magnetic exploration of a low-temperature ultramafic-hosted hydrothermal site (Lost City, 30 degrees N, MAR)", EARTH AND PLANETARY SCIENCE LETTERS., mar, 2017. Vol. 461, pp. 40-45.
Abstract: A 2003 high-resolution magnetic survey conducted by the Autonomous Underwater Vehicle ABE over the low-temperature, ultramafic-hosted hydrothermal field Lost City reveals a weak positive magnetic anomaly. This observation is in direct contrast to recent observations of strong positive magnetic anomalies documented over the high-temperature ultramafic-hosted hydrothermal vents fields Rainbow and Ashadze, which indicates that temperature may control the production of magnetization at these sites. The Lost City survey provides a unique opportunity to study a field that is, to date, one of a kind, and is an end member of ultramafic-hosted hydrothermal systems. Our results highlight the key contribution of temperature on magnetite production resulting from serpentinization reactions. Whereas high temperature promotes significant production and partitioning of iron into magnetite, low temperature favors iron partitioning into various alteration phases, resulting in a magnetite-poor rock. Moreover, the distribution of magnetic anomalies confirms results of a previous geological survey indicating the progressive migration of hydrothermal activity upslope. These discoveries contribute to the results of 25 yrs of magnetic exploration of a wide range of hydrothermal sites, from low- to high temperature and from basalt- to ultramafic-hosted, and thereby validate using high-resolution magnetics as a crucial parameter for locating and characterizing hydrothermal sites hosting unique chemosynthetic-based ecosystems and potentially mineral-rich deposits. (C) 2016 Elsevier B.V. All rights reserved.
BibTeX:
@article{ISI:000394193000005,
  author = {Szitkar, Florent and Tivey, Maurice A and Kelley, Deborah S and Karson, Jeffrey A and Fruh-Green, Gretchen L and Denny, Alden R},
  title = {Magnetic exploration of a low-temperature ultramafic-hosted hydrothermal site (Lost City, 30 degrees N, MAR)},
  journal = {EARTH AND PLANETARY SCIENCE LETTERS},
  year = {2017},
  volume = {461},
  pages = {40--45},
  doi = {10.1016/j.epsl.2016.12.033}
}
Schnur SR, Chadwick Jr. WW, Embley RW, Ferrini VL, de Ronde CEJ, Cashman KV, Deardorff ND, Merle SG, Dziak RP, Haxel JH and Matsumoto H (2017), "A decade of volcanic construction and destruction at the summit of NW Rota-1 seamount: 2004-2014", JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH. 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA, mar, 2017. Vol. 122(3), pp. 1558-1584. AMER GEOPHYSICAL UNION.
Abstract: Arc volcanoes are important to our understanding of submarine volcanism because at some sites frequent eruptions cause them to grow and collapse on human timescales. This makes it possible to document volcanic processes. Active submarine eruptions have been observed at the summit of NW Rota-1 in the Mariana Arc. We use remotely operated vehicle videography and repeat high-resolution bathymetric surveys to construct geologic maps of the summit of NW Rota-1 in 2009 and 2010 and relate them to the geologic evolution of the summit area over a 10year period (2004-2014). We find that 2009 and 2010 were characterized by different eruptive styles, which affected the type and distribution of eruptive deposits at the summit. Year 2009 was characterized by ultraslow extrusion and autobrecciation of lava at a single eruptive vent, producing a large cone of blocky lava debris. In 2010, higher-energy explosive eruptions occurred at multiple closely spaced vents, producing a thin blanket of pebble-sized tephra overlying lava flow outcrops. A landslide that occurred between 2009 and 2010 had a major effect on lithofacies distribution by removing the debris cone and other unconsolidated deposits, revealing steep massive flow cliffs. This relatively rapid alternation between construction and destruction forms one end of a seamount growth and mass wasting spectrum. Intraplate seamounts, which tend to grow larger than arc volcanoes, experience collapse events that are orders of magnitude larger and much less frequent than those occurring at subduction zone settings. Our results highlight the interrelated cyclicity of eruptive activity and mass wasting at submarine arc volcanoes.
BibTeX:
@article{ISI:000399660300001,
  author = {Schnur, Susan R and Chadwick Jr., William W and Embley, Robert W and Ferrini, Vicki L and de Ronde, Cornel E J and Cashman, Katharine V and Deardorff, Nicholas D and Merle, Susan G and Dziak, Robert P and Haxel, Joe H and Matsumoto, Haru},
  title = {A decade of volcanic construction and destruction at the summit of NW Rota-1 seamount: 2004-2014},
  journal = {JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH},
  publisher = {AMER GEOPHYSICAL UNION},
  year = {2017},
  volume = {122},
  number = {3},
  pages = {1558--1584},
  doi = {10.1002/2016JB013742}
}
Marlow J, Borrelli C, Jungbluth SP, Hoffman C, Marlow J, Girguis PR and Team A-36 (2017), "Telepresence is a potentially transformative tool for field science", PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA. 2101 CONSTITUTION AVE NW, WASHINGTON, DC 20418 USA, may, 2017. Vol. 114(19), pp. 4841-4844. NATL ACAD SCIENCES.
BibTeX:
@article{ISI:000400818400021,
  author = {Marlow, Jeffrey and Borrelli, Chiara and Jungbluth, Sean P and Hoffman, Colleen and Marlow, Jennifer and Girguis, Peter R and Team, AT-36},
  title = {Telepresence is a potentially transformative tool for field science},
  journal = {PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA},
  publisher = {NATL ACAD SCIENCES},
  year = {2017},
  volume = {114},
  number = {19},
  pages = {4841--4844},
  doi = {10.1073/pnas.1703514114}
}
Johansen C, Todd AC and MacDonald IR (2017), "Time series video analysis of bubble release processes at natural hydrocarbon seeps in the Northern Gulf of Mexico", Marine and Petroleum Geology. Vol. 82, pp. 21-34.
Abstract: This research quantifies the rate and volume of oil and gas released from two natural seep sites in the Gulf of Mexico: lease blocks GC600 (1200 m depth) and MC118 (850 m depth). Our objectives were to determine variability in release rates and bubble size at five individual vents and to investigate the effects of tidal fluctuations on bubble release. Observations with autonomous video cameras captured the formation of individual bubbles as they were released through partially exposed deposits of gas hydrate. Image processing techniques determined bubble type (oily, gaseous, and mixed: oily and gaseous), size distribution, release rate, and temporal variations (observation intervals ranged from 3 h to 26 d). A semi-automatic bubble counting algorithm was developed to analyze bubble count and release rates from video data. This method is suitable for discrete vents with small bubble streams commonly seen at seeps and is adaptable to multiple in situ set-ups. Two vents at GC600 (Birthday Candles 1 and Birthday Candles 2) were analyzed. They released oily bubbles with an average diameter of 5.0 mm at a rate of 4.7 bubbles s−1, and 1.3 bubbles s−1, respectively. Approximately 1 km away, within the GC600 seep site, two more vents (Mega Plume 1 and Mega Plume 2) were analyzed. These vents released a mixture of oily and gaseous bubbles with an average diameter of 3.9 mm at a rate of 49 bubbles s−1, and 81 bubbles s−1, respectively. The fifth vent at MC118 (Rudyville) released gaseous bubbles with an average diameter of 3.0 mm at a rate of 127 bubbles s−1. Pressure records at Mega Plume and Rudyville showed a diurnal tidal cycle (24.5 h). Rudyville was the only vent that demonstrated any positive correlation (ρ = 0.60) to the 24.5 h diurnal tidal cycle. However, these observations were not conclusive regarding tidal effects on bubble release.
BibTeX:
@article{Johansen2017,
  author = {Johansen, C and Todd, A C and MacDonald, I R},
  title = {Time series video analysis of bubble release processes at natural hydrocarbon seeps in the Northern Gulf of Mexico},
  journal = {Marine and Petroleum Geology},
  year = {2017},
  volume = {82},
  pages = {21--34},
  doi = {10.1016/j.marpetgeo.2017.01.014}
}
LaBella AL, Van Dover CL, Jollivet D and Cunningham CW (2017), "Gene flow between Atlantic and Pacific Ocean basins in three lineages of deep-sea clams (Bivalvia: Vesicomyidae: Pliocardiinae) and subsequent limited gene flow within the Atlantic", Deep Sea Research Part II: Topical Studies in Oceanography. Vol. 137, pp. 307-317.
Abstract: Pliocardiin (vesicomyid) clams rely on microbial symbionts for nutrition and are obligate inhabitants of deep-sea chemosynthetic ecosystems. Unlike many other invertebrate hosts of chemosynthetic microbes, pliocardiin clams are found in every ocean in a variety of reducing habitats, including hydrothermal vents, cold seeps, organic falls and deep-sea fans. The global distribution of pliocardiin clams suggests historical gene flow between ocean basins. We focus on 3 pliocardiin genera—‘Pliocardia' I, Calyptogena and Abyssogena—each of which has a pair of sister clades in the Atlantic and Pacific. Our work tests the hypothesis that historical gene flow between the Atlantic and Pacific Oceans within these genera was interrupted by the closure of the Panamanian seaway and tests whether isolation between the ocean basins is the result of vicariance or past colonization. These questions are investigated in the context of fossil evidence, biogeography and phylogenetics. This study revealed a set of substitution rates consistent with other invertebrate studies (μ=0.8%/My/lineage), and a set consistent with much lower rates often attributed to deep-sea organisms (μ=0.3%/My/lineage). Among the Pacific/Atlantic sister pairs, ‘Pliocardia' I COI divergence per lineage is intermediate (2.5%), Calyptogena is the highest (6.1%) and Abyssogena the lowest (0.8%). The substitution rates suggest that ‘Pliocardia' I and Calyptogena have histories of at least 2.8 My in the Atlantic, with Calyptogena likely older. The slower rate, however, is inconsistent with both the maximum age of the family and several well studied fossils: leaving the faster rate preferred. With the faster rate, the Abyssogena southwardae clade diverged from its Pacific sister clade around 1 Mya, which likely post-dates the closure of the Isthmus of Panama and the opening of the Bering Strait. In light of this recent divergence, we test the previously proposed hypothesis that there is a high level of ongoing gene flow between Atlantic populations of A. southwardae. A. southwardae has colonized a broad geographic range of seep sites including the West Florida Escarpment, the Barbados Accretionary Prism, the Lobes of Congo, and the Mid-Atlantic Ridge north and south of the Romanche Transform Fault. Coalescent methods detect gene flow between Barbados and the Mid-Atlantic ridge; and between the West Florida Escarpment and the Lobes of Congo. All other comparisons failed to detect gene flow, contrary to prevailing interpretations of connectivity across the entire Atlantic Basin.
BibTeX:
@article{LaBella2017,
  author = {LaBella, A L and Van Dover, C L and Jollivet, D and Cunningham, C W},
  title = {Gene flow between Atlantic and Pacific Ocean basins in three lineages of deep-sea clams (Bivalvia: Vesicomyidae: Pliocardiinae) and subsequent limited gene flow within the Atlantic},
  journal = {Deep Sea Research Part II: Topical Studies in Oceanography},
  year = {2017},
  volume = {137},
  pages = {307--317},
  doi = {10.1016/j.dsr2.2016.08.013}
}
Lee JM, Eltgroth SF, Boyle EA and Adkins JF (2017), "The transfer of bomb radiocarbon and anthropogenic lead to the deep North Atlantic Ocean observed from a deep sea coral", Earth and Planetary Science Letters. Vol. 458, pp. 223-232.
Abstract: Deep-ocean, View the MathML sourceΔC14, Pb concentrations, and Pb isotopes were reconstructed from a deep-sea coral Enallopsammia rostrata from 1410 m depth off of Bermuda. Our high-resolution time series is created from closely spaced radial cross sections, with samples taken from the center of concentric coral growth bands that we show to be the oldest portion of the section. Prebomb radiocarbon ages from the coral demonstrate that the vertical growth rate of the coral is linear, and the age of the coral is estimated to be 560–630 yr old based on the growth rate. Using this age model to reconstruct View the MathML sourceΔC14 in deep seawater, we first detect bomb radiocarbon at the coral growth site around 1980, and show that View the MathML sourceΔC14 increased from −80±1‰−80±1‰ (average 1930–1979) to a plateau at −39±3‰−39±3‰ (1999–2001). Pb/Ca of the coral ranges between 1.1–4.5 nmol/mol during the 16th and 17th centuries, and Pb isotope ratios (206Pb/207Pb = 1.21, 208Pb/207Pb = 2.495) in this period agree with pre-anthropogenic values found in the pelagic sediments of the North Atlantic Ocean basin. Coral Pb/Ca is slightly elevated to 6.2±0.9 nmol/mol6.2±0.9 nmol/mol between the 1740s and the 1850s and then increases to 25.1±0.2 nmol/mol25.1±0.2 nmol/mol in the 1990s. The increase in coral Pb/Ca is accompanied by a decrease in coral 206Pb/207Pb and 208Pb/207Pb, indicating that the increase was caused by the infiltration of anthropogenic Pb to the coral growth site. Comparing our data to the surface coral View the MathML sourceΔC14 and Pb records from Bermuda reveals a time scale of tracer transport from the surface ocean to the coral growth site. Some characteristic features, e.g., the bomb-derived View the MathML sourceΔC14 increase, appear in the deep ocean approximately 25 yr later than the surface, but the overall increase of View the MathML sourceΔC14 and Pb in the deep ocean is smaller and slower than the surface, showing the importance of mixing during the transport of these tracers.
BibTeX:
@article{Lee2017,
  author = {Lee, J M and Eltgroth, S F and Boyle, E A and Adkins, J F},
  title = {The transfer of bomb radiocarbon and anthropogenic lead to the deep North Atlantic Ocean observed from a deep sea coral},
  journal = {Earth and Planetary Science Letters},
  year = {2017},
  volume = {458},
  pages = {223--232},
  doi = {10.1016/j.epsl.2016.10.049}
}
Levin LA, Mendoza GF and Grupe BM (2017), "Methane seepage effects on biodiversity and biological traits of macrofauna inhabiting authigenic carbonates", Deep Sea Research Part II: Topical Studies in Oceanography. Vol. 137, pp. 26-41.
Abstract: Authigenic carbonate rocks at methane seeps are recognized as hosting diverse and abundant invertebrate assemblages, with potential forcing from fluid seepage and hydrography. Mensurative studies of carbonate macrofauna (textgreater0.3 mm) at Hydrate Ridge, OR revealed little effect of water depth and overlying oxygenation (at 600 m and 800 m) but a large influence of seepage activity on density, taxonomic composition, diversity, and biological traits (feeding, lifestyle, motility, size and calcification). Rocks exposed to active seepage had 3–4× higher total macrofaunal densities than under inactive conditions. Assemblages exhibited higher species richness and reduced evenness (greater dominance) under active seepage than inactive conditions, but no difference in H′ or rarefaction diversity. Actively seeping sites were characterized by errant (motile), bacterial grazing, small- and medium-sized, heavily calcified species, whereas inactive sites exhibited a greater diversity of feeding modes and more burrowers, sessile, large and lightly calcified species. Active rocks supported more exogonid (Syllidae), ampharetid, and cirratulid polychaetes, provannid snails, pyropeltid limpets, nemerteans, and sponges; whereas inactive rocks supported higher densities of ophiuroids, isopods, gammarid amphipods, hydroids, Typosyllis (Syllidae) and tanaids. Transplant experiments, in which rocks were transferred between active and inactive sites at Hydrate Ridge North (600 m), revealed that assemblages respond within 13 months to increase or cessation of seepage, taking on the feeding, size and calcification characteristics of the background fauna at the new site. Lifestyles and motility patterns shifted more slowly as the sessile, attached species did not track seepage as quickly. Provannid snails and pyropeltid limpets rapidly colonized rocks transplanted to active sites and disappeared when transplanted to inactive sites. Given the known variability of fluid fluxes and rapid community response, a mosaic of communities changing in space and time is hypothesized to generate the relatively high species diversity at methane seeps.
BibTeX:
@article{Levin2017,
  author = {Levin, L A and Mendoza, G F and Grupe, B M},
  title = {Methane seepage effects on biodiversity and biological traits of macrofauna inhabiting authigenic carbonates},
  journal = {Deep Sea Research Part II: Topical Studies in Oceanography},
  year = {2017},
  volume = {137},
  pages = {26--41},
  doi = {10.1016/j.dsr2.2016.05.021}
}
Love B, Lilley M, Butterfield D, Olson E and Larson B (2017), "Rapid variations in fluid chemistry constrain hydrothermal phase separation at the Main Endeavour Field", Geochemistry, Geophysics, Geosystems.
Abstract: Previous work at the Main Endeavour Field (MEF) has shown that chloride concentration in high-temperature vent fluids has not exceeded 510 mmol/kg (94% of seawater), which is consistent with brine condensation and loss at depth, followed by upward flow of a vapor phase toward the seafloor. Magmatic and seismic events have been shown to affect fluid temperature and composition and these effects help narrow the possibilities for sub-surface processes. However, chloride-temperature data alone are insufficient to determine details of phase separation in the upflow zone. Here we use variation in chloride and gas content in a set of fluid samples collected over several days from one sulfide chimney structure in the MEF to constrain processes of mixing and phase separation. The combination of gas (primarily magmatic CO2 and seawater-derived Ar) and chloride data, indicate that neither variation in the amount of brine lost, nor mixing of the vapor phase produced at depth with variable quantities of (i) brine or (ii) altered gas rich seawater that has not undergone phase separation, can explain the co-variation of gas and chloride content. The gas-chloride data require additional phase separation of the ascending vapor-like fluid. Mixing and gas partitioning calculations show that near-critical temperature and pressure conditions can produce the fluid compositions observed at Sully vent as a vapor-liquid conjugate pair or as vapor-liquid pair with some remixing, and that the gas partition coefficients implied agree with theoretically predicted values.
BibTeX:
@article{Love2017,
  author = {Love, B and Lilley, M and Butterfield, D and Olson, E and Larson, B},
  title = {Rapid variations in fluid chemistry constrain hydrothermal phase separation at the Main Endeavour Field},
  journal = {Geochemistry, Geophysics, Geosystems},
  year = {2017},
  doi = {10.1002/2016GC006550}
}
Ross SW, Rhode M and Brooke S (2017), "Deep-sea coral and hardbottom habitats on the west Florida slope, eastern Gulf of Mexico", Deep Sea Research Part I: Oceanographic Research Papers. Vol. 120, pp. 14-28.
Abstract: Until recently, benthic habitats dominated by deep-sea corals (DSC) appeared to be less extensive on the slope of the Gulf of Mexico (GOM) than in the northeast Atlantic Ocean or off the southeastern US. There are relatively few bioherms (i.e., coral-built mounds) in the northern GOM, and most DSCs are attached to existing hard substrata (e.g., authigenically formed carbonate). The primary structure-forming, DSC in the GOM is Lophelia pertusa, but structure is also provided by other living and dead scleractinians, antipatharians (black corals), octocorals (gorgonians, soft corals), hydrocorals and sponges, as well as abundant rocky substrata. The best development of DSCs in the GOM was previously documented within Viosca Knoll oil and gas lease blocks 826 and 862/906 (north-central GOM) and on the Campeche Bank (southern GOM in Mexican waters). This paper documents extensive deep reef ecosystems composed of DSC and rocky hard-bottom recently surveyed on the West Florida Slope (WFS, eastern GOM) during six research cruises (2008–2012). Using multibeam sonar, CTD casts, and video from underwater vehicles, we describe the physical and oceanographic characteristics of these deep reefs and provide size or area estimates of deep coral and hardground habitats. The multibeam sonar analyses revealed hundreds of mounds and ridges, some of which were subsequently surveyed using underwater vehicles. Mounds and ridges in textless525 m depths were usually capped with living coral colonies, dominated by L. pertusa. An extensive rocky scarp, running roughly north-south for at least 229 km, supported lower abundances of scleractinian corals than the mounds and ridges, despite an abundance of settlement substrata. Areal comparisons suggested that the WFS may exceed other parts of the GOM slope in extent of living deep coral coverage and other deep-reef habitat (dead coral and rock). The complex WFS region warrants additional studies to better understand the influences of oceanography and geology on the occurrence of DSC and associated organisms. Protection measures are being considered to ensure the long-term integrity of this diverse ecosystem.
BibTeX:
@article{Ross2017,
  author = {Ross, S W and Rhode, M and Brooke, S},
  title = {Deep-sea coral and hardbottom habitats on the west Florida slope, eastern Gulf of Mexico},
  journal = {Deep Sea Research Part I: Oceanographic Research Papers},
  year = {2017},
  volume = {120},
  pages = {14--28},
  doi = {10.1016/j.dsr.2016.12.005}
}
Sylvan JB, Wankel SD, LaRowe DE, Charoenpong CN, Huber JA, Moyer CL and Edwards KJ (2017), "Evidence for microbial mediation of subseafloor nitrogen redox processes at Loihi Seamount, Hawaii", Geochimica et Cosmochimica Acta. Vol. 198, pp. 131-150.
Abstract: The role of nitrogen cycling in submarine hydrothermal systems is far less studied than that of other biologically reactive elements such as sulfur and iron. In order to address this knowledge gap, we investigated nitrogen redox processes at Loihi Seamount, Hawaii, using a combination of biogeochemical and isotopic measurements, bioenergetic calculations and analysis of the prokaryotic community composition in venting fluids sampled during four cruises in 2006, 2008, 2009 and 2013. Concentrations of NH4+ were positively correlated to dissolved Si and negatively correlated to NO3− + NO2−, while NO2− was not correlated to NO3− + NO2−, dissolved Si or NH4+. This is indicative of hydrothermal input of NH4+ and biological mediation influencing NO2− concentrations. The stable isotope ratios of NO3− (δ15N and δ18O) was elevated with respect to background seawater, with δ18O values exhibiting larger changes than corresponding δ15N values, reflecting the occurrence of both production and reduction of NO3− by an active microbial community. δ15N-NH4+ values ranged from 0‰ to +16.7‰, suggesting fractionation during consumption and potentially N-fixation as well. Bioenergetic calculations reveal that several catabolic strategies involving the reduction of NO3− and NO2− coupled to sulfide and iron oxidation could provide energy to microbes in Loihi fluids, while 16S rRNA gene sequencing of Archaea and Bacteria in the fluids reveals groups known to participate in denitrification and N-fixation. Taken together, our data support the hypothesis that microbes are mediating N-based redox processes in venting hydrothermal fluids at Loihi Seamount.
BibTeX:
@article{Sylvan2017,
  author = {Sylvan, Jason B. and Wankel, Scott D. and LaRowe, Douglas E. and Charoenpong, Chawalit N. and Huber, Julie A. and Moyer, Craig L. and Edwards, Katrina J.},
  title = {Evidence for microbial mediation of subseafloor nitrogen redox processes at Loihi Seamount, Hawaii},
  journal = {Geochimica et Cosmochimica Acta},
  year = {2017},
  volume = {198},
  pages = {131--150},
  doi = {10.1016/j.gca.2016.10.029}
}
Syverson DD, Luhmann AJ, Tan CY, Borrok DM, Ding K and Seyfried WE (2017), "Fe isotope fractionation between chalcopyrite and dissolved Fe during hydrothermal recrystallization: An experimental study at 350 °C and 500 bars", Geochimica et Cosmochimica Acta. Vol. 200, pp. 87-109.
Abstract: Equilibrium Fe isotope fractionation between chalcopyrite and dissolved Fe was determined in acidic chloride-bearing fluid at 350 °C and 500 bars. The study utilized deformable gold-cell technology, which allowed time-series sampling of solution during chalcopyrite recrystallization and isotope exchange. A key element of the experimental design involved the addition of anomalous dissolved 57Fe to an on-going experiment as a means of determining the degree and rate of isotope exchange. Taking explicit account of imposed chemical and isotopic mass balance constraints of Fe in fluid and mineral (chalcopyrite) reservoirs, these data indicate that no more than 1000 h is required for the isotopically anomalous dissolved Fe reservoir to exchange completely with the coexisting chalcopyrite. The experimental calibration of the rate of Fe isotope exchange for the δ57Fe-spiked experiment provides critical insight for the time necessary to achieve Fe isotope exchange in two non-spiked, but otherwise identical experiments. The Fe isotope data indicate that the equilibrium fractionation between chalcopyrite and dissolved Fe, Δ56FeCpy-Fe (aq), at 350 °C is small, 0.09 ± 0.17‰ (2σ), and is in good agreement with recent theoretical equilibrium predictions. Owing to the apparent rate of Fe isotope exchange at 350 °C, it is likely that chalcopyrite formed at high temperature deep-sea vents (black smoker systems) achieves isotopic equilibrium, and effectively records the Fe isotopic composition of the coexisting end-member hydrothermal fluid. Comparison of the experimental mineral–fluid equilibrium fractionation factors with conjugate chalcopyrite and dissolved Fe pairs sampled from high temperature hydrothermal vent systems at Axial Caldera and Main Endeavour Field (Juan de Fuca Ridge) are in agreement with this inference. The experimental data were further used to determine the mineral–mineral equilibrium Fe isotope fractionation between pyrite-chalcopyrite, Δ56FePyr-Cpy, at 350 °C by combining previously determined pyrite-Fe2+(aq) equilibrium fractionation data with chalcopyrite-Fe2+(aq) from this study. The empirically determined Δ56FePyr-Cpy value, 0.90 ± 0.34‰ (2σ), is consistent with theoretical predictions, and when coupled with mineral–fluid Fe isotope fractionation systematics and experimentally determined exchange rates, helps to delineate processes of sulfide mineralization in hydrothermal systems.
BibTeX:
@article{Syverson2017,
  author = {Syverson, D D and Luhmann, A J and Tan, C Y and Borrok, D M and Ding, K and Seyfried, W E},
  title = {Fe isotope fractionation between chalcopyrite and dissolved Fe during hydrothermal recrystallization: An experimental study at 350 °C and 500 bars},
  journal = {Geochimica et Cosmochimica Acta},
  year = {2017},
  volume = {200},
  pages = {87--109},
  doi = {10.1016/j.gca.2016.12.002}
}
Beaudoin DJ, Carmichael CA, Nelson RK, Reddy CM, Teske AP and Edgcomb VP (2016), "Impact of protists on a hydrocarbon-degrading bacterial community from deep-sea Gulf of Mexico sediments: A microcosm study", Deep-Sea Research. Part II: Topical Studies in Oceanography. Vol. 129(0), pp. 350-359.
Abstract: In spite of significant advancements towards understanding the dynamics of petroleum hydrocarbon degrading microbial consortia, the impacts (direct or indirect via grazing activities) of bacterivorous protists remain largely unknown. Microcosm experiments were used to examine whether protistan grazing affects the petroleum hydrocarbon degradation capacity of a deep-sea sediment microbial community from an active Gulf of Mexico cold seep. Differences in n-alkane content between native sediment microcosms and those treated with inhibitors of eukaryotes were assessed by comprehensive two-dimensional gas chromatography following 30–90 day incubations and analysis of shifts in microbial community composition using small subunit ribosomal RNA gene clone libraries. More biodegradation was observed in microcosms supplemented with eukaryotic inhibitors. SSU rRNA gene clone libraries from oil-amended treatments revealed an increase in the number of proteobacterial clones (particularly γ-proteobacteria) after spiking sediments with diesel oil. Bacterial community composition shifted, and degradation rates increased, in treatments where protists were inhibited, suggesting protists affect the hydrocarbon degrading capacity of microbial communities in sediments collected at this Gulf of Mexico site.
BibTeX:
@article{Beaudoin2016,
  author = {Beaudoin, D J and Carmichael, C A and Nelson, R K and Reddy, C M and Teske, A P and Edgcomb, V P},
  title = {Impact of protists on a hydrocarbon-degrading bacterial community from deep-sea Gulf of Mexico sediments: A microcosm study},
  journal = {Deep-Sea Research. Part II: Topical Studies in Oceanography},
  year = {2016},
  volume = {129},
  number = {0},
  pages = {350--359},
  url = {http://www.sciencedirect.com/science/article/pii/S0967064514000216},
  doi = {10.1016/j.dsr2.2014.01.007}
}
Burkett AM, Rathburn AE, Perez EM, Levin LA and Martin JB (2016), "Colonization of over a thousand Cibicidoides wuellerstorfi (foraminifera: Schwager, 1866) on artificial substrates in seep and adjacent off-seep locations in dysoxic, deep-sea environments", Deep Sea Research Part I: Oceanographic Research Papers. Vol. 117, pp. 39-50.
Abstract: After ˜1 yr on the seafloor at water depths of ˜700 m on Hydrate Ridge in the Pacific, eight colonization experiments composed primarily of a plastic mesh cube (from here on refered to as SEA3, for Seafloor Epibenthic Attachment Cubes) were colonized by 1076 Cibicidoides wuellerstorfi on ˜1841 cm2 of experimental substrate. This species is typically considered an indicator of well-oxygenated conditions, and recruitment of such large numbers in bottom waters with low dissolved oxygen availability (0.24–0.37 mL/L) indicate that this taxon may not be as limited by oxygen as previously thought. Clues about substrate preferences were evident from the distribution, or lack thereof, of individuals among plastic mesh, coated steel frame, wooden dowels and reflective tape. Abundance, individual size distributions within cage populations and isotopic biogeochemistry of living foraminifera colonizing experimental substrates were compared between active seep and adjacent off-seep experiment locations, revealing potential differences between these environments. Few studies have examined foraminiferal colonization of hard substrates in the deep-sea and to our knowledge no previous study has compared foraminiferal colonization of active seep and off-seep substrates from the same region. This study provides initial results of recruitment, colonization, geochemical and morphological aspects of the paleoceanographically significant species, C. wuellerstorfi, from dynamic deep-sea environments. Further experimental deployments of SEA3s will provide a means to assess relatively unknown ecologic dynamics of important foraminiferal deep-sea species.
BibTeX:
@article{Burkett2016,
  author = {Burkett, A M and Rathburn, A E and Perez, Elena M and Levin, L A and Martin, J B},
  title = {Colonization of over a thousand Cibicidoides wuellerstorfi (foraminifera: Schwager, 1866) on artificial substrates in seep and adjacent off-seep locations in dysoxic, deep-sea environments},
  journal = {Deep Sea Research Part I: Oceanographic Research Papers},
  year = {2016},
  volume = {117},
  pages = {39--50},
  doi = {10.1016/j.dsr.2016.08.011}
}
Chadwick WW, Paduan JB, Clague DA, Dreyer BM, Merle SG, Bobbitt AM, Caress DW, Philip BT, Kelley DS and Nooner SL (2016), "Voluminous eruption from a zoned magma body after an increase in supply rate at Axial Seamount", Geophysical Research Letters. Vol. 43, pp. 12,063-12,070.
Abstract: Axial Seamount is the best monitored submarine volcano in the world, providing an exceptional window into the dynamic interactions between magma storage, transport, and eruption processes in a mid-ocean ridge setting. An eruption in April 2015 produced the largest volume of erupted lava since monitoring and mapping began in the mid-1980s after the shortest repose time, due to a recent increase in magma supply. The higher rate of magma replenishment since 2011 resulted in the eruption of the most mafic lava in the last 500–600 years. Eruptive fissures at the volcano summit produced pyroclastic ash that was deposited over an area of at least 8 km2. A systematic spatial distribution of compositions is consistent with a single dike tapping different parts of a thermally and chemically zoned magma reservoir that can be directly related to previous multichannel seismic-imaging results.
BibTeX:
@article{Chadwick2016,
  author = {Chadwick, W W and Paduan, J B and Clague, D A and Dreyer, B M and Merle, S G and Bobbitt, A M and Caress, D W and Philip, B T and Kelley, D S and Nooner, S L},
  title = {Voluminous eruption from a zoned magma body after an increase in supply rate at Axial Seamount},
  journal = {Geophysical Research Letters},
  year = {2016},
  volume = {43},
  pages = {12,063--12,070},
  doi = {10.1002/2016GL071327}
}
Edgcomb VP, Pachiadaki M, Mara P, Kormas K, Leadbetter ER and Bernhard JM (2016), "Gene expression profiling of microbial activities and interactions in sediments under haloclines of E. Mediterranean deep hypersaline anoxic basins", ISME Journal. Vol. 10, pp. 2643-2657.
Abstract: Deep-sea hypersaline anoxic basins (DHABs) in the Eastern Mediterranean Sea are considered some of the most polyextreme habitats on Earth. In comparison to microbial activities occurring within the haloclines and brines of these unusual water column habitats near the Mediterranean seafloor, relatively little is known about microbial metabolic activities in the underlying sediments. In addition, it is not known whether activities are shaped by the unique chemistries of the different DHAB brines and whether evidence exists for active microbial eukaryotes in those sediments. Metatranscriptome analysis was applied to sediment samples collected using ROV Jason from underneath the haloclines of Urania, Discovery and L'Atalante DHABs and a control site. We report on expression of genes associated with sulfur and nitrogen cycling, putative osmolyte biosynthetic pathways and ion transporters, trace metal detoxification, selected eukaryotic activities (particularly of fungi), microbemicrobe interactions, and motility in sediments underlying the haloclines of three DHABs. Relative to our control sediment sample collected outside of Urania Basin, microbial communities (including eukaryotes) in the Urania and Discovery DHAB sediments showed upregulation of expressed genes associated with nitrogen transformations, osmolyte biosynthesis, heavy metals resistance and metabolism, eukaryotic organelle functions, and cell-cell interactions. Sediments underlying DHAB haloclines that have cumulative physico-chemical stressors within the limits of tolerance for microoorganisms can therefore be hotspots of activity in the deep Mediterranean Sea.
BibTeX:
@article{Edgcomb2016,
  author = {Edgcomb, V P and Pachiadaki, M and Mara, P and Kormas, K and Leadbetter, E R and Bernhard, J M},
  title = {Gene expression profiling of microbial activities and interactions in sediments under haloclines of E. Mediterranean deep hypersaline anoxic basins},
  journal = {ISME Journal},
  year = {2016},
  volume = {10},
  pages = {2643--2657},
  doi = {10.1038/ismej.2016.58}
}
Garcia MO, Weis D, Jicha BR, Ito G and Hanano D (2016), "Petrology and geochronology of lavas from Ka‘ula Volcano: Implications for rejuvenated volcanism of the Hawaiian mantle plume", Geochimica et Cosmochimica Acta. Vol. 185, pp. 278-301.
Abstract: Marine surveying and submersible sampling of Ka‘ula Volcano, located 100 km off the axis of the Hawaiian chain, revealed widespread areas of young volcanism. New 40Ar/39Ar and geochemical analyses of the olivine-phyric submarine and subaerial volcanic rocks show that Ka‘ula is shrouded with 1.9–0.5 Ma alkalic basalts. The ages and chemistry of these rocks overlap with rejuvenated lavas on nearby, northern Hawaiian Island shields (Ni‘ihau, Kaua‘i and South Kaua‘i Swell). Collectively, these rejuvenated lavas cover a vast area (∼7000 km2), much more extensive than any other area of rejuvenated volcanism worldwide. Ka‘ula rejuvenated lavas range widely in alkalinity and incompatible element abundances (e.g., up to 10× P2O5 at a given MgO value) and ratios indicating variable degrees of melting of a heterogeneous source. Heavy REE elements in Ka‘ula lavas are pinned at a mantle normalized Yb value of 10 ± 1, reflecting the presence of garnet in the source. Trace element ratios indicate the source also contained phlogopite and an Fe–Ti oxide. The new Ka‘ula ages show that rejuvenated volcanism was nearly coeval from ∼0.3 to 0.6 Ma along a 450 km segment of the Hawaiian Islands (from West Maui to north of Ka‘ula). The ages and volumes for rejuvenated volcanism are inconsistent with all but one geodynamic melting model proposed to date. This model advocates a significant contribution of pyroxenite to rejuvenated magmas. Analyses of olivine phenocryst compositions suggest a major (33–69%) pyroxenite component in Ka‘ula rejuvenated lavas, which correlates positively with radiogenic Pb isotope ratios for Ka‘ula. This correlation is also observed in lavas from nearby South Kaua‘i lavas, as was reported for Atlantic oceanic islands. The presence of pyroxenite in the source may have extended the duration and volume of Hawaiian rejuvenated volcanism.
BibTeX:
@article{Garcia2016,
  author = {Garcia, M O and Weis, D and Jicha, B R and Ito, G and Hanano, D},
  title = {Petrology and geochronology of lavas from Ka‘ula Volcano: Implications for rejuvenated volcanism of the Hawaiian mantle plume},
  journal = {Geochimica et Cosmochimica Acta},
  year = {2016},
  volume = {185},
  pages = {278--301},
  doi = {10.1016/j.gca.2016.03.025}
}
Garcia-Pineda O, MacDonald I, Silva M, Shedd W, Daneshgar Asl S and Schumaker B (2016), "Transience and persistence of natural hydrocarbon seepage in Mississippi Canyon, Gulf of Mexico", Deep Sea Research Part II: Topical Studies in Oceanography. Vol. 129, pp. 119-129.
Abstract: Analysis of the magnitude of oil discharged from natural hydrocarbon seeps can improve understanding of the carbon cycle and the Gulf of Mexico (GOM) ecosystem. With use of a large archive of remote sensing data, in combination with geophysical and multibeam data, we identified, mapped, and characterized natural hydrocarbon seeps in the Macondo prospect region near the wreck site of the drill-rig Deepwater Horizon (DWH). Satellite image processing and the cluster analysis revealed locations of previously undetected seep zones. Including duplicate detections, a total of 562 individual gas plumes were also observed in multibeam surveys. In total, SAR imagery confirmed 52 oil-producing seep zones in the study area. In almost all cases gas plumes were associated with oil-producing seep zones. The cluster of seeps in the vicinity of lease block MC302 appeared to host the most persistent and prolific oil vents. Oil slicks and gas plumes observed over the DWH site were consistent with discharges of residual oil from the wreckage. In contrast with highly persistent oil seeps observed in the Green Canyon and Garden Banks lease areas, the seeps in the vicinity of Macondo Prospect were intermittent. The difference in the number of seeps and the quantity of surface oil detected in Green Canyon was almost two orders of magnitude greater than in Mississippi Canyon.
BibTeX:
@article{Garcia-Pineda2016,
  author = {Garcia-Pineda, O and MacDonald, I and Silva, M and Shedd, W and Daneshgar Asl, S and Schumaker, B},
  title = {Transience and persistence of natural hydrocarbon seepage in Mississippi Canyon, Gulf of Mexico},
  journal = {Deep Sea Research Part II: Topical Studies in Oceanography},
  year = {2016},
  volume = {129},
  pages = {119--129},
  doi = {10.1016/j.dsr2.2015.05.011}
}
Gueguen B, Rouxel OJ, Rouget M-L, Bollinger C, Ponzevera E, Germain Y and Fouquet Y (2016), "Comparative geochemistry of four ferromanganese crusts from the Pacific Ocean and significance for the use of Ni isotopes as paleoceanographic tracers", Geochimica et Cosmochimica Acta. Vol. 189, pp. 214-235.
Abstract: Ferromanganese (Fe-Mn) crusts are potential archive of the Ni isotope composition of seawater through time. In this study we aim at (1) understanding Ni isotope fractionation mechanisms and metal enrichment processes in Fe-Mn deposits, (2) addressing global vs. local control of Ni isotope composition of these deposits. Two Fe-Mn crusts from the North Pacific Ocean (Apuupuu Seamount, Hawaii) and two Fe-Mn crusts from the South Pacific Ocean (near Rurutu Island, Austral archipelago of French Polynesia) were characterized for their elemental geochemistry and Ni isotope composition. Geochemical analyses were performed at millimeter intervals in order to provide time-resolved record of Ni isotopes. Chronology and growth rates were determined using cosmogenic 10Be isotope abundances. The results show that, despite different growth rates, textures and geochemical patterns, Fe-Mn crusts from both North and South Pacific Oceans have fairly homogenous Ni isotope compositions over the last ∼17 Ma, yielding average δ60/58Ni values of 1.79 ± 0.21‰ (2sd, n = 31) and 1.73 ± 0.21‰ (2sd, n = 21) respectively. In one crust sample, however, layers directly in contact with the altered substrate show anomalously light δ60/58Ni values down to 0.25 ± 0.05‰ (2se) together with rejuvenated 10Be/9Be ratios correlating with elevated Ni/Mn ratios. Such patterns are best explained by protracted fluid–rock interactions leading to alteration of Mn-phases after crust formation. Isotopically light Ni would be the result of Ni isotope fractionation during adsorption rather than the contribution of external Ni sources (e.g. hydrothermal sources) having light Ni isotope compositions. The combination of our results with previously published data on Fe-Mn crusts indicates that the average Ni isotope composition in deep waters has not changed through the Cenozoic (∼70 Ma). We propose that Ni isotope variations in Fe-Mn crusts may not only record variations of Ni sources to the oceans, but also post-depositional processes depending on the growth history and geological settings of Fe-Mn crusts.
BibTeX:
@article{Gueguen2016,
  author = {Gueguen, B and Rouxel, O J and Rouget, M-L and Bollinger, C and Ponzevera, E and Germain, Y and Fouquet, Y},
  title = {Comparative geochemistry of four ferromanganese crusts from the Pacific Ocean and significance for the use of Ni isotopes as paleoceanographic tracers},
  journal = {Geochimica et Cosmochimica Acta},
  year = {2016},
  volume = {189},
  pages = {214--235},
  doi = {10.1016/j.gca.2016.06.005}
}
Hendrickx ME, Hinojosa-Corona A and Ayon-Parente M (2016), "New records of the deep-sea anemone Phelliactis callicyclus Riemann-Zurneck, 1973 (Cnidaria, Actiniaria, Hormathiidae) from the Gulf of California, Mexico", Zootaxa. Vol. 4178, pp. 145-150.
Abstract: Specimens of a deep-sea anemone were observed in photographs and video footage taken with the Remotely Operated Vehicle JASON (WHOI Deep Submergence Laboratory) in the Gulf of California, Mexico, in May 2008. Comparison of our material with photographs and description of this species available in literature indicate that the sea anemones filmed during the JASON survey are most likely to represent Phelliactis callicyclus Riemann-Zurneck, 1973. This species has previously been reported from a locality in the Gulf of California near the present record. During the JASON survey, 28 specimens of P. callicyclus were spotted in 27 locations during six dives. The specimens occurred on angular rock outcrops along the escarpments of the transform faults of the Gulf of California, between depths of 993-2543 m and at temperatures ranging from 2.3 to 4.5 degrees C. Based on these new records, Phelliactis callicyclus appears to be widely spread in the Gulf of California.
BibTeX:
@article{Hendrickx2016,
  author = {Hendrickx, M E and Hinojosa-Corona, A and Ayon-Parente, M},
  title = {New records of the deep-sea anemone Phelliactis callicyclus Riemann-Zurneck, 1973 (Cnidaria, Actiniaria, Hormathiidae) from the Gulf of California, Mexico},
  journal = {Zootaxa},
  year = {2016},
  volume = {4178},
  pages = {145--150},
  doi = {10.11646/zootaxa.4178.1.8}
}
Anantharaman K, Breier JA and Dick GJ (2016), "Metagenomic resolution of microbial functions in deep-sea hydrothermal plumes across the Eastern Lau Spreading Center", ISME JOURNAL., jan, 2016. Vol. 10(1), pp. 225-239.
Abstract: Microbial processes within deep-sea hydrothermal plumes affect ocean
biogeochemistry on global scales. In rising hydrothermal plumes, a
combination of microbial metabolism and particle formation processes
initiate the transformation of reduced chemicals like hydrogen sulfide,
hydrogen, methane, iron, manganese and ammonia that are abundant in
hydrothermal vent fluids. Despite the biogeochemical importance of this
rising portion of plumes, it is understudied in comparison to neutrally
buoyant plumes. Here we use metagenomics and bioenergetic modeling to
describe the abundance and genetic potential of microorganisms in
relation to available electron donors in five different hydrothermal
plumes and three associated background deep-sea waters from the Eastern
Lau Spreading Center located in the Western Pacific Ocean. Three hundred
and thirty one distinct genomic `bins' were identified, comprising an
estimated 951 genomes of archaea, bacteria, eukarya and viruses. A
significant proportion of these genomes is from novel microorganisms and
thus reveals insights into the energy metabolism of heretofore unknown
microbial groups. Community-wide analyses of genes encoding enzymes that
oxidize inorganic energy sources showed that sulfur oxidation was the
most abundant and diverse chemolithotrophic microbial metabolism in the
community. Genes for sulfur oxidation were commonly present in genomic
bins that also contained genes for oxidation of hydrogen and methane,
suggesting metabolic versatility in these microbial groups. The relative
diversity and abundance of genes encoding hydrogen oxidation was
moderate, whereas that of genes for methane and ammonia oxidation was
low in comparison to sulfur oxidation. Bioenergetic-thermodynamic
modeling supports the metagenomic analyses, showing that oxidation of
elemental sulfur with oxygen is the most dominant catabolic reaction in
the hydrothermal plumes. We conclude that the energy metabolism of
microbial communities inhabiting rising hydrothermal plumes is dictated
by the underlying plume chemistry, with a dominant role for sulfur-based
chemolithoautotrophy.
BibTeX:
@article{ISI:000366671300021,
  author = {Anantharaman, Karthik and Breier, John A and Dick, Gregory J},
  title = {Metagenomic resolution of microbial functions in deep-sea hydrothermal plumes across the Eastern Lau Spreading Center},
  journal = {ISME JOURNAL},
  year = {2016},
  volume = {10},
  number = {1},
  pages = {225--239},
  doi = {10.1038/ismej.2015.81}
}
Klose J, Aistleitner K, Horn M, Krenn L, Dirsch V, Zehl M and Bright M (2016), "Trophosome of the Deep-Sea Tubeworm Riftia pachyptila Inhibits Bacterial Growth", PLOS ONE., jan, 2016. Vol. 11(1)
Abstract: The giant tubeworm Riftia pachyptila lives in symbiosis with the
chemoautotrophic gamma-proteobacterium Cand. Endoriftia persephone.
Symbionts are released back into the environment upon host death in
high-pressure experiments, while microbial fouling is not involved in
trophosome degradation. Therefore, we examined the antimicrobial effect
of the tubeworm's trophosome and skin. The growth of all four tested
Gram-positive, but only of one of the tested Gram-negative bacterial
strains was inhibited by freshly fixed and degrading trophosome
(incubated up to ten days at either warm or cold temperature), while no
effect on Saccharomyces cerevisiae was observed. The skin did not show
antimicrobial effects. A liquid chromatography-mass spectrometric
analysis of the ethanol supernatant of fixed trophosomes lead to the
tentative identification of the phospholipids 1-palmitoleyl-2-lyso-
phosphatidylethanolamine, 2-palmitoleyl-1-lyso-phosphatidylethanolamine
and the free fatty acids palmitoleic, palmitic and oleic acid, which are
known to have an antimicrobial effect. As a result of tissue autolysis,
the abundance of the free fatty acids increased with longer incubation
time of trophosome samples. This correlated with an increasing growth
inhibition of Bacillus subtilis and Listeria welshimeri, but not of the
other bacterial strains. Therefore, the free fatty acids produced upon
host degradation could be the cause of inhibition of at least these two
bacterial strains.
BibTeX:
@article{ISI:000367801400177,
  author = {Klose, Julia and Aistleitner, Karin and Horn, Matthias and Krenn, Liselotte and Dirsch, Verena and Zehl, Martin and Bright, Monika},
  title = {Trophosome of the Deep-Sea Tubeworm Riftia pachyptila Inhibits Bacterial Growth},
  journal = {PLOS ONE},
  year = {2016},
  volume = {11},
  number = {1},
  doi = {10.1371/journal.pone.0146446}
}
Dowell F, Cardman Z, Dasarathy S, Kellermann MY, Lipp JS, Ruff SE, Biddle JF, McKay LJ, MacGregor BJ, Lloyd KG, Albert DB, Mendlovitz H, Hinrichs K-U and Teske A (2016), "Microbial Communities in Methane- and Short Chain Alkane-Rich Hydrothermal Sediments of Guaymas Basin", FRONTIERS IN MICROBIOLOGY., jan, 2016. Vol. 7
Abstract: The hydrothermal sediments of Guaymas Basin, an active spreading center
in the Gulf of California (Mexico), are rich in porewater methane,
short-chain alkanes, sulfate and sulfide, and provide a model system to
explore habitat preferences of microorganisms, including
sulfate-dependent, methane- and short chain alkane-oxidizing microbial
communities. In this study, hot sediments (above 60 degrees C) covered
with sulfur-oxidizing microbial mats surrounding a hydrothermal mound
(termed ``Mat Mound'') were characterized by porewater geochemistry of
methane, C-2-C-6 short-chain alkanes, sulfate, sulfide, sulfate
reduction rate measurements, in situ temperature gradients, bacterial
and archaeal 16S rRNA gene clone libraries and V6 tag pyrosequencing.
The most abundantly detected groups in the Mat mound sediments include
anaerobic methane-oxidizing archaea of the ANME-1 lineage and its sister
Glade ANME-1Guaymas, the uncultured bacterial groups SEEP-SRB2 within
the Deltaproteobacteria and the separately branching HotSeep-1 Group;
these uncultured bacteria are candidates for sulfate-reducing alkane
oxidation and for sulfate-reducing syntrophy with ANME archaea. The
archaeal dataset indicates distinct habitat preferences for ANME-1,
ANME-1-Guaymas, and ANME-2 archaea in Guaymas Basin hydrothermal
sediments. The bacterial groups SEEP-SRB2 and HotSeep-1 co-occur with
ANME-1 and ANME-1Guaymas in hydrothermally active sediments underneath
microbial mats in Guaymas Basin. We propose the working hypothesis that
this mixed bacterial and archaeal community catalyzes the oxidation of
both methane and short-chain alkanes, and constitutes a microbial
community signature that is characteristic for hydrothermal and/or cold
seep sediments containing both substrates.
BibTeX:
@article{ISI:000368893500001,
  author = {Dowell, Frederick and Cardman, Zena and Dasarathy, Srishti and Kellermann, Matthias Y and Lipp, Julius S and Ruff, S Emil and Biddle, Jennifer F and McKay, Luke J and MacGregor, Barbara J and Lloyd, Karen G and Albert, Daniel B and Mendlovitz, Howard and Hinrichs, Kai-Uwe and Teske, Andreas},
  title = {Microbial Communities in Methane- and Short Chain Alkane-Rich Hydrothermal Sediments of Guaymas Basin},
  journal = {FRONTIERS IN MICROBIOLOGY},
  year = {2016},
  volume = {7},
  doi = {10.3389/fmicb.2016.00017}
}
Van Campenhout J, Vanreusel A, Van Belleghem S and Derycke S (2016), "Transcription, Signaling Receptor Activity, Oxidative Phosphorylation, and Fatty Acid Metabolism Mediate the Presence of Closely Related Species in Distinct Intertidal and Cold-Seep Habitats", GENOME BIOLOGY AND EVOLUTION., jan, 2016. Vol. 8(1), pp. 51-69.
Abstract: Bathyal cold seeps are isolated extreme deep-sea environments
characterized by low species diversity while biomass can be high. The
Hakon Mosby mud volcano (Barents Sea, 1,280 m) is a rather stable
chemosynthetic driven habitat characterized by prominent surface
bacterial mats with high sulfide concentrations and low oxygen levels.
Here, the nematode Halomonhystera hermesithrives in high abundances
(11,000 individuals 10 cm(-2)). Halomonhystera hermesi is a member of
the intertidal Halomonhystera disjuncta species complex that includes
five cryptic species (GD 1-5). GD1-5's common habitat is characterized
by strong environmental fluctuations. Here, we compared the
transcriptomes of H. hermesi and GD1, H. hermesi's closest relative.
Genes encoding proteins involved in oxidative phosphorylation are more
strongly expressed in H. hermesi than in GD1, and many genes were only
observed in H. hermesi while being completely absent in GD1. Both
observations could in part be attributed to high sulfide concentrations
and low oxygen levels. Additionally, fatty acid elongation was also
prominent in H. hermesi confirming the importance of highly unsaturated
fatty acids in this species. Significant higher amounts of transcription
factors and genes involved in signaling receptor activity were observed
in GD1 (many of which were completely absent in H. hermesi), allowing
fast signaling and transcriptional reprogramming which can mediate
survival in dynamic intertidal environments. GC content was
approximately 8% higher in H. hermesi coding unigenes resulting in
differential codon usage between both species and a higher proportion of
amino acids with GC-rich codons in H. hermesi. In general our results
showed that most pathways were active in both environments and that only
three genes are under natural selection. This indicates that also
plasticity should be taken in consideration in the evolutionary history
of Halomonhystera species. Such plasticity, as well as possible
preadaptation to low oxygen and high sulfide levels might have played an
important role in the establishment of a cold-seep Halomonhystera
population.
BibTeX:
@article{ISI:000370971600005,
  author = {Van Campenhout, Jelle and Vanreusel, Ann and Van Belleghem, Steven and Derycke, Sofie},
  title = {Transcription, Signaling Receptor Activity, Oxidative Phosphorylation, and Fatty Acid Metabolism Mediate the Presence of Closely Related Species in Distinct Intertidal and Cold-Seep Habitats},
  journal = {GENOME BIOLOGY AND EVOLUTION},
  year = {2016},
  volume = {8},
  number = {1},
  pages = {51--69},
  doi = {10.1093/gbe/evv242}
}
Meyer JL, Jaekel U, Tully BJ, Glazer BT, Wheat CG, Lin H-T, Hsieh C-C, Cowen JP, Hulme SM, Girguis PR and Huber JA (2016), "A distinct and active bacterial community in cold oxygenated fluids circulating beneath the western flank of the Mid-Atlantic ridge", SCIENTIFIC REPORTS., mar, 2016. Vol. 6
Abstract: The rock-hosted, oceanic crustal aquifer is one of the largest
ecosystems on Earth, yet little is known about its indigenous
microorganisms. Here we provide the first phylogenetic and functional
description of an active microbial community residing in the cold oxic
crustal aquifer. Using subseafloor observatories, we recovered crustal
fluids and found that the geochemical composition is similar to bottom
seawater, as are cell abundances. However, based on relative abundances
and functional potential of key bacterial groups, the crustal fluid
microbial community is heterogeneous and markedly distinct from
seawater. Potential rates of autotrophy and heterotrophy in the crust
exceeded those of seawater, especially at elevated temperatures (25
degrees C) and deeper in the crust. Together, these results reveal an
active, distinct, and diverse bacterial community engaged in both
heterotrophy and autotrophy in the oxygenated crustal aquifer, providing
key insight into the role of microbial communities in the ubiquitous
cold dark subseafloor biosphere.
BibTeX:
@article{ISI:000371206300001,
  author = {Meyer, Julie L and Jaekel, Ulrike and Tully, Benjamin J and Glazer, Brian T and Wheat, C Geoffrey and Lin, Huei-Ting and Hsieh, Chih-Chiang and Cowen, James P and Hulme, Samuel M and Girguis, Peter R and Huber, Julie A},
  title = {A distinct and active bacterial community in cold oxygenated fluids circulating beneath the western flank of the Mid-Atlantic ridge},
  journal = {SCIENTIFIC REPORTS},
  year = {2016},
  volume = {6},
  doi = {10.1038/srep22541}
}
McKay L, Klokman VW, Mendlovitz HP, LaRowe DE, Hoer DR, Albert D, Amend JP and Teske A (2016), "Thermal and geochemical influences on microbial biogeography in the hydrothermal sediments of Guaymas Basin, Gulf of California", ENVIRONMENTAL MICROBIOLOGY REPORTS., feb, 2016. Vol. 8(1), pp. 150-161.
Abstract: Extreme thermal gradients and compressed metabolic zones limit the depth
range of microbial colonization in hydrothermally active sediments at
Guaymas Basin. We investigated the physicochemical characteristics of
this ecosystem and their influence on microbial community structure.
Temperature-related trends of C-13 values of methane and dissolved
inorganic carbon from 36 sediment cores suggest in situ thermal limits
for microbial anaerobic methane oxidation and organic carbon
re-mineralization near 80 degrees C and 100 degrees C respectively.
Temperature logging probes deposited in hydrothermal sediments for 8
days demonstrate substantial thermal fluctuations of up to 25 degrees C.
Putative anaerobic methanotroph (ANME) populations dominate the archaeal
community, transitioning from ANME-1 archaea in warm surficial sediments
towards ANME-1 Guaymas archaea as temperatures increase downcore. Since
ANME archaea performing anaerobic oxidation of methane double on longer
time scales (months) compared with relatively rapid in situ temperature
fluctuations (hours to days), we conclude that ANME archaea possess a
high tolerance for short-term shifts in the thermal regime.
BibTeX:
@article{ISI:000371481100019,
  author = {McKay, Luke and Klokman, Vincent W and Mendlovitz, Howard P and LaRowe, Douglas E and Hoer, Daniel R and Albert, Daniel and Amend, Jan P and Teske, Andreas},
  title = {Thermal and geochemical influences on microbial biogeography in the hydrothermal sediments of Guaymas Basin, Gulf of California},
  journal = {ENVIRONMENTAL MICROBIOLOGY REPORTS},
  year = {2016},
  volume = {8},
  number = {1},
  pages = {150--161},
  doi = {10.1111/1758-2229.12365}
}
Georgian SE, DeLeo D, Durkin A, Gomez CE, Kurman M, Lunden JJ and Cordes EE (2016), "Oceanographic patterns and carbonate chemistry in the vicinity of cold-water coral reefs in the Gulf of Mexico: Implications for resilience in a changing ocean", LIMNOLOGY AND OCEANOGRAPHY., mar, 2016. Vol. 61(2), pp. 648-665.
Abstract: To accurately assess the threat that global climate change poses to marine systems, a detailed baseline of the current carbonate chemistry and other oceanographic conditions is required. Despite the heightened vulnerability of deep-sea communities to ocean acidification, there have been relatively few studies investigating the carbonate chemistry immediately above cold-water coral reefs. Here, we present data collected during five cruises from 2010 to 2014 in the northern Gulf of Mexico and quantify the carbonate system and other oceanographic parameters in offshore surface-waters, the water column, and at deep benthic sites. Benthic sites containing the scleractinian cold-water coral L. pertusa occurred in waters with a relatively wide temperature range (6.8-13.6 degrees C), low potential density (sigma(theta)=26.9 +/- 0.3 kg m(-3)), low dissolved oxygen concentration (111.3 +/- 2.0 mu mol kg(-1)), low pH(T) (7.87 +/- 0.04), low Omega(ARAG) (1.31 +/- 0.14), and a low availability of carbonate ions (94.4 +/- 9.2 mu mol kg(-1)) compared with L. pertusa habitats in other regions. Based on previous modelling and experimental results, these values place L. pertusa at the edge of its viable niche in the deep Gulf of Mexico. However, significantly elevated total alkalinity (+139-44 mu mol kg(-1)) was detected above large L. pertusa mounds, suggesting that carbonate dissolution within the mounds may be partially ameliorating the direct effects of ocean acidification. Together, these results provide an important baseline for assessing future oceanographic changes in the Gulf of Mexico and for predicting the resilience of cold-water coral reefs to global climate and ocean change.
BibTeX:
@article{ISI:000372166500012,
  author = {Georgian, Samuel E and DeLeo, Danielle and Durkin, Alanna and Gomez, Carlos E and Kurman, Melissa and Lunden, Jay J and Cordes, Erik E},
  title = {Oceanographic patterns and carbonate chemistry in the vicinity of cold-water coral reefs in the Gulf of Mexico: Implications for resilience in a changing ocean},
  journal = {LIMNOLOGY AND OCEANOGRAPHY},
  year = {2016},
  volume = {61},
  number = {2},
  pages = {648--665},
  doi = {10.1002/lno.10242}
}
Jones DS, Flood BE and Bailey JV (2016), "Metatranscriptomic insights into polyphosphate metabolism in marine sediments", ISME JOURNAL., apr, 2016. Vol. 10(4), pp. 1015-1019.
Abstract: Microorganisms can influence inorganic phosphate (P-i) in pore waters,
and thus the saturation state of phosphatic minerals, by accumulating
and hydrolyzing intracellular polyphosphate (poly-P). Here we used
comparative metatranscriptomics to explore microbial poly-P utilization
in marine sediments. Sulfidic marine sediments from methane seeps near
Barbados and from the Santa Barbara Basin (SBB) oxygen minimum zone were
incubated under oxic and anoxic sulfidic conditions. Pi was sequestered
under oxic conditions and liberated under anoxic conditions. Transcripts
homologous to poly-P kinase type 2 (ppk2) were 6-22 x more abundant in
metatranscriptomes from the anoxic incubations, suggesting that
reversible poly-P degradation by Ppk2 may be an important metabolic
response to anoxia by marine microorganisms. Overall, diverse taxa
differentially expressed homologues of genes for poly-P degradation
(ppk2 and exopolyphosphatase) under different incubation conditions.
Sulfur-oxidizing microorganisms appeared to preferentially express genes
for poly-P degradation under anoxic conditions, which may impact
phosphorus cycling in a wide range of oxygen-depleted marine settings.
BibTeX:
@article{ISI:000372364000020,
  author = {Jones, Daniel S and Flood, Beverly E and Bailey, Jake V},
  title = {Metatranscriptomic insights into polyphosphate metabolism in marine sediments},
  journal = {ISME JOURNAL},
  year = {2016},
  volume = {10},
  number = {4},
  pages = {1015--1019},
  doi = {10.1038/ismej.2015.169}
}
Stewart LC, Llewellyn JG, Butterfield DA, Lilley MD and Holden JF (2016), "Hydrogen and thiosulfate limits for growth of a thermophilic, autotrophic Desulfurobacterium species from a deep-sea hydrothermal vent", ENVIRONMENTAL MICROBIOLOGY REPORTS., apr, 2016. Vol. 8(2), pp. 196-200.
Abstract: Hydrothermal fluids (341 degrees C and 19 degrees C) were collected textless1m
apart from a black smoker chimney and a tubeworm mound on the Boardwalk
edifice at the Endeavour Segment in the northeastern Pacific Ocean to
study anaerobic microbial growth in hydrothermal mineral deposits.
Geochemical modelling of mixed vent fluid and seawater suggests the
mixture was anoxic above 55 degrees C and that low H-2 concentrations
(79molkg(-1) in end-member hydrothermal fluid) limit anaerobic
hydrogenotrophic growth above this temperature. A thermophilic,
hydrogenotrophic sulfur reducer, Desulfurobacterium strain HR11, was
isolated from the 19 degrees C fluid raising questions about its
H-2-dependent growth kinetics. Strain HR11 grew at 40-77 degrees C
(T-opt 72-75 degrees C), pH 5-8.5 (pH(opt) 6-7) and 1-5% (wt vol(-1))
NaCl (NaClopt 3-4%). The highest growth rates occurred when S2O32- and
S degrees were reduced to H2S. Modest growth occurred by NO3- reduction.
Monod constants for its growth were K-s of 30M for H-2 and K-s of 20M
for S2O32- with a (max) of 2.0h(-1). The minimum H-2 and S2O32-
concentrations for growth were 3M and 5M respectively. Possible sources
of S2O32- and S degrees are from abiotic dissolved sulfide and pyrite
oxidation by O-2.
BibTeX:
@article{ISI:000372931000004,
  author = {Stewart, Lucy C and Llewellyn, James G and Butterfield, David A and Lilley, Marvin D and Holden, James F},
  title = {Hydrogen and thiosulfate limits for growth of a thermophilic, autotrophic Desulfurobacterium species from a deep-sea hydrothermal vent},
  journal = {ENVIRONMENTAL MICROBIOLOGY REPORTS},
  year = {2016},
  volume = {8},
  number = {2},
  pages = {196--200},
  doi = {10.1111/1758-2229.12368}
}
Kellermann MY, Yoshinaga MY, Wegener G, Krukenberg V and Hinrichs K-U (2016), "Tracing the production and fate of individual archaeal intact polar lipids using stable isotope probing", ORGANIC GEOCHEMISTRY., may, 2016. Vol. 95, pp. 13-20.
Abstract: Analysis of cellular membrane lipids has been widely applied to describe
the microbial community composition in natural systems. When combined
with stable isotope probing (SIP) experiments, deuterium label (D2O)
uptake into lipids enables assessment of microbial biomass production.
We performed SIP on methane-rich, hydrothermally-heated sediments to
examine the de novo production of individual archaeal intact polar
lipids (IPLs) by mesophilic anaerobic methane oxidizing group-1 archaea
(ANME-1). The greatest extent of label uptake was by phosphatidyl
glycerol archaeol (PG-AR), reaching 50% of the medium's label
concentration in only 10 days. This indicates PG-AR as an important cell
membrane lipid during the active growth phase of mesophilic ANME-1. Much
less label uptake was into intact polar glycerol dibiphytanyl glycerol
tetraethers (GDGTs), especially for those bound to diglycosidic head
groups. The low production of these GDGTs contrasts with their
predominance in ANME-1-dominated natural samples. We attribute the
differential label uptake among individual IPLs to the ANME-1 tetraether
biosynthetic pathway. This mechanism likely involves head-to-head
condensation of two molecules of PG-AR and progressive substitution of
PG by glycosidic head groups. The observation that ANME-1 invest in the
synthesis of diethers during optimum growth suggests intact ARs and/or
phosphate-bearing tetraethers as important biomarkers for actively
growing populations in natural environments, while the diglycosidic
GDGTs appear to signal stationary ANME-1 communities. (C) 2016 Elsevier
Ltd. All rights reserved.
BibTeX:
@article{ISI:000372952900002,
  author = {Kellermann, Matthias Y and Yoshinaga, Marcos Y and Wegener, Gunter and Krukenberg, Viola and Hinrichs, Kai-Uwe},
  title = {Tracing the production and fate of individual archaeal intact polar lipids using stable isotope probing},
  journal = {ORGANIC GEOCHEMISTRY},
  year = {2016},
  volume = {95},
  pages = {13--20},
  doi = {10.1016/j.orggeochem.2016.02.004}
}
Baquiran J-PM, Ramirez GA, Haddad AG, Toner BM, Hulme S, Wheat CG, Edwards KJ and Orcutt BN (2016), "Temperature and Redox Effect on Mineral Colonization in Juan de Fuca Ridge Flank Subsurface Crustal Fluids", FRONTIERS IN MICROBIOLOGY., mar, 2016. Vol. 7
Abstract: To examine microbe-mineral interactions in subsurface oceanic crust, we
evaluated microbial colonization on crustal minerals that were incubated
in borehole fluids for 1 year at the seafloor wellhead of a crustal
borehole observatory (IODP Hole U1301A, Juan de Fuca Ridge flank) as
compared to an experiment that was not exposed to subsurface crustal
fluids (at nearby IODP Hole U1301B). In comparison to previous studies
at these same sites, this approach allowed assessment of the effects of
temperature, fluid chemistry, and/or mineralogy on colonization patterns
of different mineral substrates, and an opportunity to verify the
approach of deploying colonization experiments at an observatory
wellhead at the seafloor instead of within the borehole. The Hole U1301B
deployment did not have biofilm growth, based on microscopy and DNA
extraction, thereby confirming the integrity of the colonization design
against bottom seawater intrusion. In contrast, the Hole U1301A
deployment supported biofilms dominated by Epsilonproteobacteria (43.5%
of 370 16S rRNA gene clone sequences) and Gammaproteobacteria (29.3%).
Sequence analysis revealed overlap in microbial communities between
different minerals incubated at the Hole U1301A wellhead, indicating
that mineralogy did not separate biofilm structure within the 1-year
colonization experiment. Differences in the Hole U1301A wellhead biofilm
community composition relative to previous studies from within the
borehole using similar mineral substrates suggest that temperature and
the diffusion of dissolved oxygen through plastic components influenced
the mineral colonization experiments positioned at the wellhead. This
highlights the capacity of low abundance crustal fluid taxa to rapidly
establish communities on diverse mineral substrates under changing
environmental conditions such as from temperature and oxygen.
BibTeX:
@article{ISI:000373276200001,
  author = {Baquiran, Jean-Paul M and Ramirez, Gustavo A and Haddad, Amanda G and Toner, Brandy M and Hulme, Samuel and Wheat, Charles G and Edwards, Katrina J and Orcutt, Beth N},
  title = {Temperature and Redox Effect on Mineral Colonization in Juan de Fuca Ridge Flank Subsurface Crustal Fluids},
  journal = {FRONTIERS IN MICROBIOLOGY},
  year = {2016},
  volume = {7},
  doi = {10.3339/fmicb.2016.00396}
}
Robador A, LaRowe DE, Jungbluth SP, Lin H-T, Rappe MS, Nealson KH and Amend JP (2016), "Nanocalorimetric Characterization of Microbial Activity in Deep Subsurface Oceanic Crustal Fluids", FRONTIERS IN MICROBIOLOGY., apr, 2016. Vol. 7
Abstract: Although fluids within the upper oceanic basaltic crust harbor a
substantial fraction of the total prokaryotic cells on Earth, the energy
needs of this microbial population are unknown. In this study, a
nanocalorimeter (sensitivity down to 1.2 nW ml(-1)) was used to measure
the enthalpy of microbially catalyzed reactions as a function of
temperature in samples from two distinct crustal fluid aquifers.
Microorganisms in unamended, warm (63 degrees C) and geochemically
altered anoxic fluids taken from 292 meters sub-basement (msb) near the
Juan de Fuca Ridge produced 267.3 mJ of heat over the course of 97 h
during a step-wise isothermal scan from 35.5 to 85.0 degrees C. Most of
this heat signal likely stems from the germination of thermophilic
endospores (6.66 x 10(4) cells ml(-1) FLUID) and their subsequent
metabolic activity at temperatures greater than 50 degrees C. The
average cellular energy consumption (5.68 pW cell(-1)) reveals the high
metabolic potential of a dormant community transported by fluids
circulating through the ocean crust. By contrast, samples taken from 293
msb from cooler (3.8 degrees C), relatively unaltered oxic fluids,
produced 12.8 mJ of heat over the course of 14 h as temperature ramped
from 34.8 to 43.0 degrees C. Corresponding cell-specific energy turnover
rates (0.18 pW cell(-1)) were converted to oxygen uptake rates of 24.5
nmol O-2 ml(-1) FLUID d(-1), validating previous model predictions of
microbial activity in this environment. Given that the investigated
fluids are characteristic of expansive areas of the upper oceanic crust,
the measured metabolic heat rates can be used to constrain boundaries of
habitability and microbial activity in the oceanic crust.
BibTeX:
@article{ISI:000373321200001,
  author = {Robador, Alberto and LaRowe, Douglas E and Jungbluth, Sean P and Lin, Huei-Ting and Rappe, Michael S and Nealson, Kenneth H and Amend, Jan P},
  title = {Nanocalorimetric Characterization of Microbial Activity in Deep Subsurface Oceanic Crustal Fluids},
  journal = {FRONTIERS IN MICROBIOLOGY},
  year = {2016},
  volume = {7},
  doi = {10.3389/fmicb.2016.00454}
}
Bowles M, Hunter KS, Samarkin V and Joye S (2016), "Patterns and variability in geochemical signatures and microbial activity within and between diverse cold seep habitats along the lower continental slope, Northern Gulf of Mexico", DEEP-SEA RESEARCH PART II-TOPICAL STUDIES IN OCEANOGRAPHY., jul, 2016. Vol. 129, pp. 31-40.
Abstract: We collected 69 sediment cores from distinct ecological and geological
settings along the deep slope in the Northern Gulf of Mexico to evaluate
whether specific geochemical- or habitat-related factors correlated with
rates of microbial processes and geochemical signatures. By collecting
replicate cores from distinct habitats across multiple sites, we
illustrate and quantify the heterogeneity of cold seep geochemistry and
microbial activity. These data also document the factors driving unique
aspects of the geochemistry of deep slope gas, oil and brine seeps.
Surprisingly little variation was observed between replicate (n=2-5)
cores within sites for most analytes (except methane), implying that the
common practice of collecting one core for geochemical analysis can
capture the signature of a habitat in most cases. Depth-integrated
concentrations of methane, dissolved inorganic carbon (DIC), and calcium
were the predominant geochemical factors that correlated with a site's
ecological or geological settings. Pore fluid methane concentration was
related to the phosphate and DIC concentration, as well as to rates of
sulfate reduction. While distinctions between seep habitats were
identified from geochemical signatures, habitat specific geochemistry
varied little across sites. The relative concentration of dissolved
inorganic nitrogen versus phosphorus suggests that phosphorus
availability limits biomass production at cold seeps. Correlations
between calcium, chloride, and phosphate concentrations were indicative
of brine-associated phosphate transport, suggesting that in addition to
the co-migration of methane, dissolved organic carbon, and ammonium with
brine, phosphate delivery is also associated with brine advection. (C)
2016 Published by Elsevier Ltd.
BibTeX:
@article{ISI:000378670800005,
  author = {Bowles, Marshall and Hunter, Kimberley S and Samarkin, Vladimir and Joye, Samantha},
  title = {Patterns and variability in geochemical signatures and microbial activity within and between diverse cold seep habitats along the lower continental slope, Northern Gulf of Mexico},
  journal = {DEEP-SEA RESEARCH PART II-TOPICAL STUDIES IN OCEANOGRAPHY},
  year = {2016},
  volume = {129},
  pages = {31--40},
  doi = {10.1016/j.dsr2.2016.02.011}
}
Martens CS, Mendlovitz HP, Seim H, Lapham L and D'Emidio M (2016), "Sustained in situ measurements of dissolved oxygen, methane and water transport processes in the benthic boundary layer at MC118, northern Gulf of Mexico", DEEP-SEA RESEARCH PART II-TOPICAL STUDIES IN OCEANOGRAPHY., jul, 2016. Vol. 129, pp. 41-52.
Abstract: Within months of the BP Macondo Wellhead blowout, elevated methane
concentrations within the water column revealed a significant retention
of light hydrocarbons in deep waters plus corresponding dissolved oxygen
(DO) deficits. However, chemical plume tracking efforts were hindered by
a lack of in situ monitoring capabilities. Here, we describe results
from in situ time-series, lander-based investigations of physical and
biogeochemical processes controlling dissolved oxygen, and methane at
Mississippi Canyon lease block 118 (similar to 18 km from the oil spill)
conducted shortly after the blowout through April 2012. Multiple sensor
arrays plus open-cylinder flux chambers (''chimneys'') deployed from
a benthic lander collected oxygen, methane, pressure, and current speed
and direction data within one meter of the seafloor. The ROVARD lander
system was deployed for an initial 21-day test experiment
(9/13/2010-10/04/2010) at 882 m depth before a longer 160-day deployment
(10/24/2011-4/01/2012) at 884 m depth. Temporal variability in current
directions and velocities and water temperatures revealed strong
influences of bathymetrically steered currents and overlying along-shelf
flows on local and regional water transport processes. DO concentrations
and temperature were inversely correlated as a result of water mass
mixing processes. Flux chamber measurements during the 160-day
deployment revealed total oxygen utilization (TOU) averaging 11.6
mmol/m(2) day. Chimney DO concentrations measured during the 21-day
deployment exhibited quasi-daily variations apparently resulting from an
interaction between near inertial waves and the steep topography of an
elevated scarp immediately adjacent to the 21-day deployment site that
modulated currents at the top of the chimney. Variability in dissolved
methane concentrations suggested significant temporal variability in gas
release from nearby hydrocarbon seeps and/or delivery by local water
transport processes. Free-vehicle (lander) monitoring over time scales
of months to years utilizing in situ sensors can provide an
understanding of processes controlling water transport, respiration and
the fate and impacts of accidental and natural gas and oil releases. (C)
2015 Elsevier Ltd. All rights reserved.
BibTeX:
@article{ISI:000378670800006,
  author = {Martens, Christopher S and Mendlovitz, Howard P and Seim, Harvey and Lapham, Laura and D'Emidio, Marco},
  title = {Sustained in situ measurements of dissolved oxygen, methane and water transport processes in the benthic boundary layer at MC118, northern Gulf of Mexico},
  journal = {DEEP-SEA RESEARCH PART II-TOPICAL STUDIES IN OCEANOGRAPHY},
  year = {2016},
  volume = {129},
  pages = {41--52},
  doi = {10.1016/j.dsr2.2015.11.012}
}
Reveillaud J, Reddington E, McDermott J, Algar C, Meyer JL, Sylva S, Seewald J, German CR and Huber JA (2016), "Subseafloor microbial communities in hydrogen-rich vent fluids from hydrothermal systems along the Mid-Cayman Rise", ENVIRONMENTAL MICROBIOLOGY., jun, 2016. Vol. 18(6, SI), pp. 1970-1987.
Abstract: Warm fluids emanating from hydrothermal vents can be used as windows
into the rocky subseafloor habitat and its resident microbial community.
Two new vent systems on the Mid-Cayman Rise each exhibits novel geologic
settings and distinctively hydrogen-rich vent fluid compositions. We
have determined and compared the chemistry, potential energy yielding
reactions, abundance, community composition, diversity, and function of
microbes in venting fluids from both sites: Piccard, the world's deepest
vent site, hosted in mafic rocks; and Von Damm, an adjacent,
ultramafic-influenced system. Von Damm hosted a wider diversity of
lineages and metabolisms in comparison to Piccard, consistent with
thermodynamic models that predict more numerous energy sources at
ultramafic systems. There was little overlap in the phylotypes found at
each site, although similar and dominant hydrogen-utilizing genera were
present at both. Despite the differences in community structure, depth,
geology, and fluid chemistry, energetic modelling and metagenomic
analysis indicate near functional equivalence between Von Damm and
Piccard, likely driven by the high hydrogen concentrations and elevated
temperatures at both sites. Results are compared with hydrothermal sites
worldwide to provide a global perspective on the distinctiveness of
these newly discovered sites and the interplay among rocks, fluid
composition and life in the subseafloor.
BibTeX:
@article{ISI:000380376700024,
  author = {Reveillaud, Julie and Reddington, Emily and McDermott, Jill and Algar, Christopher and Meyer, Julie L and Sylva, Sean and Seewald, Jeffrey and German, Christopher R and Huber, Julie A},
  title = {Subseafloor microbial communities in hydrogen-rich vent fluids from hydrothermal systems along the Mid-Cayman Rise},
  journal = {ENVIRONMENTAL MICROBIOLOGY},
  year = {2016},
  volume = {18},
  number = {6, SI},
  pages = {1970--1987},
  doi = {10.1111/1462-2920.13173}
}
Nooner SL and Chadwick Jr. WW (2016), "Inflation-predictable behavior and co-eruption deformation at Axial Seamount", SCIENCE., dec, 2016. Vol. 354(6318), pp. 1399-1403.
Abstract: Deformation of the ground surface at active volcanoes provides information about magma movements at depth. Improved seafloor deformation measurements between 2011 and 2015 documented a fourfold increase in magma supply and confirmed that Axial Seamount's eruptive behavior is inflation-predictable, probably triggered by a critical level of magmatic pressure. A 2015 eruption was successfully forecast on the basis of this deformation pattern and marked the first time that deflation and tilt were captured in real time by a new seafloor cabled observatory, revealing the timing, location, and volume of eruption-related magma movements. Improved modeling of the deformation suggests a steeply dipping prolate-spheroid pressure source beneath the eastern caldera that is consistent with the location of the zone of highest melt within the subcaldera magma reservoir determined from multichannel seismic results.
BibTeX:
@article{ISI:000390261300037,
  author = {Nooner, Scott L and Chadwick Jr., William W},
  title = {Inflation-predictable behavior and co-eruption deformation at Axial Seamount},
  journal = {SCIENCE},
  year = {2016},
  volume = {354},
  number = {6318},
  pages = {1399--1403},
  doi = {10.1126/science.aah4666}
}
Jungbluth SP, Bowers RM, Lin H-T, Cowen JP and Rappe MS (2016), "Novel microbial assemblages inhabiting crustal fluids within mid-ocean ridge flank subsurface basalt", ISME Journal. Vol. 10, pp. 2033-2047.
Abstract: Although little is known regarding microbial life within our planet's rock-hosted deep subseafloor biosphere, boreholes drilled through deep ocean sediment and into the underlying basaltic crust provide invaluable windows of access that have been used previously to document the presence of microorganisms within fluids percolating through the deep ocean crust. In this study, the analysis of 1.7 million small subunit ribosomal RNA genes amplified and sequenced from marine sediment, bottom seawater and basalt-hosted deep subseafloor fluids that span multiple years and locations on the Juan de Fuca Ridge flank was used to quantitatively delineate a subseafloor microbiome comprised of distinct bacteria and archaea. Hot, anoxic crustal fluids tapped by newly installed seafloor sampling observatories at boreholes U1362A and U1362B contained abundant bacterial lineages of phylogenetically unique Nitrospirae, Aminicenantes, Calescamantes and Chloroflexi. Although less abundant, the domain Archaea was dominated by unique, uncultivated lineages of marine benthic group E, the Terrestrial Hot Spring Crenarchaeotic Group, the Bathyarchaeota and relatives of cultivated, sulfate-reducing Archaeoglobi. Consistent with recent geochemical measurements and bioenergetic predictions, the potential importance of methane cycling and sulfate reduction were imprinted within the basalt-hosted deep subseafloor crustal fluid microbial community. This unique window of access to the deep ocean subsurface basement reveals a microbial landscape that exhibits previously undetected spatial heterogeneity.
BibTeX:
@article{Jungbluth2016,
  author = {Jungbluth, S P and Bowers, R M and Lin, H-T and Cowen, J P and Rappe, M S},
  title = {Novel microbial assemblages inhabiting crustal fluids within mid-ocean ridge flank subsurface basalt},
  journal = {ISME Journal},
  year = {2016},
  volume = {10},
  pages = {2033--2047},
  doi = {10.1038/ismej.2015.248}
}
Krukenberg V, Harding K, Richter M, Gloeckner FO, Gruber-Vodicka HR, Adam B, Berg JS, Knittel K, Tegetmeyer HE, Boetius A and Wegener G (2016), "Candidatus Desulfofervidus auxilii, a hydrogenotrophic sulfate-reducing bacterium involved in the thermophilic anaerobic oxidation of methane", Environmental Microbiology. Vol. 18(9), pp. 3073-3091.
Abstract: The anaerobic oxidation ofmethane (AOM) ismediated by consortia of anaerobic methane-oxidizing archaea (ANME) and their specific partner bacteria. In thermophilic AOM consortia enriched from Guaymas Basin, members of the ANME-1 clade are associated with bacteria of the HotSeep-1 cluster, which likely perform direct electron exchange via nanowires. The partner bacterium was enriched with hydrogen as sole electron donor and sulfate as electron acceptor. Based on phylogenetic, genomic and metabolic characteristics we propose to name this chemolithoautotrophic sulfate reducer Candidatus Desulfofervidus auxilii. Ca.D. auxilii grows on hydrogen at temperatures between 50 degrees C and 70 degrees C with an activity optimum at 60 degrees C and doubling time of 4-6 days. Its genome draft encodes for canonical sulfate reduction, periplasmic and soluble hydrogenases and autotrophic carbon fixation via the reductive tricarboxylic acid cycle. The presence of genes for pili formation and cytochromes, and their similarity to genes of Geobacter spp., indicate a potential for syntrophic growth via direct interspecies electron transfer when the organism grows in consortia with ANME. This first ANME-free enrichment of an AOM partner bacterium and its characterization opens the perspective for a deeper understanding of syntrophy in anaerobic methane oxidation.
BibTeX:
@article{Krukenberg2016,
  author = {Krukenberg, V and Harding, K and Richter, M and Gloeckner, F O and Gruber-Vodicka, H R and Adam, B and Berg, J S and Knittel, K and Tegetmeyer, H E and Boetius, A and Wegener, G},
  title = {Candidatus Desulfofervidus auxilii, a hydrogenotrophic sulfate-reducing bacterium involved in the thermophilic anaerobic oxidation of methane},
  journal = {Environmental Microbiology},
  year = {2016},
  volume = {18},
  number = {9},
  pages = {3073--3091},
  doi = {10.1111/1462-2920.13283}
}
Lin TJ, Ver Eecke HC, Breves EA, Dyar MD, Jamieson JW, Hannington MD, Dahle H, Bishop JL, Lane MD, Butterfield DA, Kelley DS, Lilley MD, Baross JA and Holden JF (2016), "Linkages between mineralogy, fluid chemistry, and microbial communities within hydrothermal chimneys from the Endeavour Segment, Juan de Fuca Ridge", Geochemistry, Geophysics, Geosystems. Vol. 17, pp. 300-323.
Abstract: Rock and fluid samples were collected from three hydrothermal chimneys at the Endeavour Segment, Juan de Fuca Ridge to evaluate linkages among mineralogy, fluid chemistry, and microbial community composition within the chimneys. Mössbauer, midinfrared thermal emission, and visible-near infrared spectroscopies were utilized for the first time to characterize vent mineralogy, in addition to thin-section petrography, X-ray diffraction, and elemental analyses. A 282°C venting chimney from the Bastille edifice was composed primarily of sulfide minerals such as chalcopyrite, marcasite, and sphalerite. In contrast, samples from a 300°C venting chimney from the Dante edifice and a 321°C venting chimney from the Hot Harold edifice contained a high abundance of the sulfate mineral anhydrite. Geochemical modeling of mixed vent fluids suggested the oxic-anoxic transition zone was above 100°C at all three vents, and that the thermodynamic energy available for autotrophic microbial redox reactions favored aerobic sulfide and methane oxidation. As predicted, microbes within the Dante and Hot Harold chimneys were most closely related to mesophilic and thermophilic aerobes of the Betaproteobacteria and Gammaproteobacteria and sulfide-oxidizing autotrophic Epsilonproteobacteria. However, most of the microbes within the Bastille chimney were most closely related to mesophilic and thermophilic anaerobes of the Deltaproteobacteria, especially sulfate reducers, and anaerobic hyperthermophilic archaea. The predominance of anaerobes in the Bastille chimney indicated that other environmental factors promote anoxic conditions. Possibilities include the maturity or fluid flow characteristics of the chimney, abiotic Fe2+ and S2− oxidation in the vent fluids, or O2 depletion by aerobic respiration on the chimney outer wall.
BibTeX:
@article{Lin2016,
  author = {Lin, T J and Ver Eecke, H C and Breves, E A and Dyar, M D and Jamieson, J W and Hannington, M D and Dahle, H and Bishop, J L and Lane, M D and Butterfield, D A and Kelley, D S and Lilley, M D and Baross, J A and Holden, J F},
  title = {Linkages between mineralogy, fluid chemistry, and microbial communities within hydrothermal chimneys from the Endeavour Segment, Juan de Fuca Ridge},
  journal = {Geochemistry, Geophysics, Geosystems},
  year = {2016},
  volume = {17},
  pages = {300--323},
  doi = {10.1002/2015GC006091}
}
Macelloni L, Lutken CB, Ingrassia M, D' Emidio M and Pizzi M (2016), "Mesoscale biogeophysical characterization of Woolsey Mound (northern Gulf of Mexico), a new attribute of natural marine hydrocarbon seeps architecture", Marine Geology. Vol. 380, pp. 330-344.
Abstract: Located on the continental slope in 900 m of water, Woolsey Mound dominates seafloor morphology at Mississippi Canyon 118. The carbonate-hydrate mound is the site of the Gulf of Mexico Hydrates Research Consortium's seafloor observatory to investigate and monitor hydrographic, geophysical, geological, geochemical and biological processes of the hydrocarbon system, northern Gulf of Mexico. Innovative survey and monitoring systems, sensors, and tools have been developed to extract samples and data to unravel the history, character and composition of the site. Many hours of visual data have been collected to investigate benthic communities thriving at the cold seep site associated with the mound. These communities' habitats are described here, for the first time, in terms of faunal assemblage, substrate nature, and presence/absence of chemosynthetic species. Based on these factors, we grouped them into four benthic meso-habitats. We speculate that the spatial distribution of these meso-habitats is large enough to make this characteristic comparable to the geophysical response of the seismo-acoustic systems. We have tested this hypothesis carefully analyzing the relationship between benthic habitats zonation and the geophysical response of Side Scan Sonar, Chirp Subbottom, Surface Source Deep Receiver (SSDR) vertical incidence profiler and 3-D oil industry multichannel data. We observe that the geophysical response is not unique, a single habitat may correlate with many geophysical attributes, or a single geophysical attribute may span many habitats. However, we find that geophysical data can predict seep locations. They can also convey some information concerning community composition and complexity that function as proxies for seep duration/age while specific community components are believed to reflect composition of seep fluids. Although preliminary, this approach represents a novel classification/characterization for seafloor hydrocarbon seeps, one that reflects a historical component.
BibTeX:
@article{Macelloni2016,
  author = {Macelloni, L and Lutken, C B and Ingrassia, M and D' Emidio, M and Pizzi, M},
  title = {Mesoscale biogeophysical characterization of Woolsey Mound (northern Gulf of Mexico), a new attribute of natural marine hydrocarbon seeps architecture},
  journal = {Marine Geology},
  year = {2016},
  volume = {380},
  pages = {330--344},
  doi = {10.1016/j.margeo.2016.03.016}
}
Maher WA, Duncan E, Dilly G, Foster S, Krikowa F, Lombi E, Scheckel K and Girguis P (2016), "Arsenic concentrations and species in three hydrothermal vent worms, Ridgeia piscesae, Paralvinella sulficola and Paralvinella palmiformis", Deep Sea Research Part I: Oceanographic Research Papers. Vol. 116, pp. 41-48.
Abstract: Hydrothermal vents are surficial expressions of subsurface geological and hydrological processes. Fluids emitting from active vents are chemically distinct from bottom seawater, and are enriched in dissolved metals and metalloids, including arsenic. Vent organisms accumulate arsenic but the arsenic speciation in these non-photosynthetic organisms is largely unknown. Here, arsenic concentrations and chemical species were measured in three deep sea hydrothermal vent worms (Ridgeia piscesae, Paralvinella sulfincola and Paralvinella palmiformis ) from the Juan de Fuca Ridge in the Northwest pacific. R. piscesae has similar arsenic concentrations (3.8–35 µg g−1) to shallow water polychaetes while P. sulfincola and P. palmiformis have significantly higher arsenic concentrations (420–1417 and 125–321 µg g−1 respectively). R. piscesae contains appreciable quantities of inorganic arsenic (36±14%), monomethyl arsenic (2±2%), dimethyl arsenic (34±21%), an unknown methyl arsenical (7±16%), OSO3-arsenosugar (5±9%), TETRA (4±5%), ThioPO4/ThioDMAE (1±2%) and an unknown thio-arsenical (12±14%). These results suggests that host and symbionts are either involved in the methylation of arsenic, or are bathed in fluids enriched in methylated arsenic as a result of free-living microbial activity. The host carrying out methylation, however, cannot be ruled out. In contrast, 96–97% of the arsenic in P. sulfincola and P. palmiformis is inorganic arsenic, likely the result of arsenic precipitation within and upon the mucus they ingest while feeding. While all worms have oxo- and thio arsenosugars (2–30%), Paralvinella also have small amounts of arsenobetaine (textless0.001–0.21%). The presence of arsenosugars, arsenobetaine and other minor arsenic species in the absence of photosynthesising algae/bacteria indicates that they may be formed by vent animals in the absence of sunlight, but at this time their formation cannot be explained.
BibTeX:
@article{Maher2016,
  author = {Maher, W A and Duncan, E and Dilly, G and Foster, S and Krikowa, F and Lombi, E and Scheckel, K and Girguis, P},
  title = {Arsenic concentrations and species in three hydrothermal vent worms, Ridgeia piscesae, Paralvinella sulficola and Paralvinella palmiformis},
  journal = {Deep Sea Research Part I: Oceanographic Research Papers},
  year = {2016},
  volume = {116},
  pages = {41--48},
  doi = {10.1016/j.dsr.2016.07.009}
}
Martin P, Goodkin NF, Stewart JA, Foster GL, Sikes EL, White HK, Hennige S and Roberts JM (2016), "Deep-sea coral δ13C: A tool to reconstruct the difference between seawater pH and δ11B-derived calcifying fluid pH", Geophysical Research Letters. Vol. 43, pp. 299-308.
Abstract: The boron isotopic composition (δ11B) of coral skeleton is a proxy for seawater pH. However, δ11B-based pH estimates must account for the pH difference between seawater and the coral calcifying fluid, ΔpH. We report that skeletal δ11B and ΔpH are related to the skeletal carbon isotopic composition (δ13C) in four genera of deep-sea corals collected across a natural pH range of 7.89–8.09, with ΔpH related to δ13C by ΔpH = 0.029 × δ13C + 0.929, r2 = 0.717. Seawater pH can be reconstructed by determining ΔpH from δ13C and subtracting it from the δ11B-derived calcifying fluid pH. The uncertainty for reconstructions is ±0.12 pH units (2 standard deviations) if estimated from regression prediction intervals or between ±0.04 and ±0.06 pH units if estimated from confidence intervals. Our new approach quantifies and corrects for vital effects, offering improved accuracy relative to an existing δ11B versus seawater pH calibration with deep-sea scleractinian corals.
BibTeX:
@article{Martin2016,
  author = {Martin, P and Goodkin, N F and Stewart, J A and Foster, G L and Sikes, E L and White, H K and Hennige, S and Roberts, J M},
  title = {Deep-sea coral δ13C: A tool to reconstruct the difference between seawater pH and δ11B-derived calcifying fluid pH},
  journal = {Geophysical Research Letters},
  year = {2016},
  volume = {43},
  pages = {299--308},
  doi = {10.1002/2015GL066494}
}
McNichol J (2016), "Productivity, metabolism and physiology of free-living chemoautotrophic Epsilonproteobacteria"
Abstract: Chemoautotrophic ecosystems at deep-sea hydrothermal vents were discovered in 1977, but not until 1995 were free-living autotrophic Epsilonproteobacteria identified as important microbial community members. Because the deep-sea is food-starved, the autotrophic metabolism of hydrothermal vent Epsilonproteobacteria may be very important for deep-sea consumers. However, quantifying their metabolic activities in situ has remained difficult, and biochemical mechanisms underlying their autotrophic physiology are poorly described. To gain insight into environmental processes, an approach was developed for incubations of microbes at in situ pressure and temperature (25 MPa, 24°C) with various combinations of electron donors/acceptors (H2, O2 and NO3 and 13HCO3) as a tracer to track carbon fixation. During short (18-24 h) incubations of low-temperature vent fluids from Crab Spa (9°N East Pacific Rise), the concentration of electron donors/acceptors and cell numbers were monitored to quantify microbial processes. Measured rates were generally higher than previous studies, and the stoichiometry of microbially-catalyzed redox reactions revealed new insights into sulfur and nitrogen cycling. Single-cell, taxonomically-resolved tracer incorporation showed Epsilonproteobacteria dominated carbon fixation, and their growth efficiency was calculated based on electron acceptor consumption. Using these data, in situ primary productivity, microbial standing stock, and average biomass residence time of the deep-sea vent subseafloor biosphere were estimated. Finally, the population structures of the most abundant genera Sulfurimonas and Thioreductor were shown to be strongly influenced by pO2 and temperature respectively, providing a mechanism for niche differentiation in situ. To gain insights into the core biochemical reactions underlying autotrophy in Epsilonprotebacteria, a theoretical metabolic model of Sulfurimonas denitrificans was developed. Validated iteratively by comparing in silico yields with data from chemostat experiments, the model generated hypotheses explaining critical, yet so far unresolved reactions supporting chemoautotrophy in Epsilonproteobacteria. For example, it provides insight into how energy is conserved during sulfur oxidation coupled to denitrification, how reverse electron transport produces ferredoxin for carbon fixation, and why aerobic growth yields are only slightly higher compared to denitrification. As a whole, this thesis provides important contributions towards understanding core mechanisms of chemoautrophy, as well as the in situ productivity, physiology and ecology of autotrophic Epsilonproteobacteria.
BibTeX:
@phdthesis{McNichol2016,
  author = {McNichol, J},
  title = {Productivity, metabolism and physiology of free-living chemoautotrophic Epsilonproteobacteria},
  year = {2016},
  doi = {10.1575/1912/8450}
}
McNichol J, Sylva SP, Thomas F, Taylor CD, Sievert SM and Seewald JS (2016), "Assessing microbial processes in deep-sea hydrothermal systems by incubation at in situ temperature and pressure", Deep Sea Research Part I: Oceanographic Research Papers. Vol. 115, pp. 221-232.
Abstract: At deep-sea hydrothermal vents, a large source of potential chemical energy is created when reducing vent fluid and oxidizing seawater mix. In this environment, chemolithoautotrophic microbes catalyze exergonic redox reactions which in turn provide the energy needed to fuel their growth and the fixation of CO2 into biomass. In addition to producing new organic matter, this process also consumes compounds contained both in vent fluid and entrained seawater (e.g. H2, NO3−). Despite their biogeochemical importance, such reactions have remained difficult to quantify due to methodological limitations. To address this knowledge gap, this study reports a novel application of isobaric gas-tight fluid samplers for conducting incubations of hydrothermal vent fluids at in situ temperature and pressure. Eighteen ˜24 h incubations were carried out, representing seven distinct conditions that examine amendments consisting of different electron donors and acceptors. Microbial activity was observed in all treatments, and time series chemical measurements showed that activity was limited by electron acceptor supply, confirming predictions based on geochemical data. Also consistent with these predictions, the presence of nitrate increased rates of hydrogen consumption and yielded ammonium as a product of nitrate respiration. The stoichiometry of predicted redox reactions was also determined, revealing that the sulfur and nitrogen cycles are incompletely understood at deep-sea vents, and likely involve unknown intermediate redox species. Finally, the measured rates of redox processes were either equal to or far greater than what has been reported in previous studies where in situ conditions were not maintained. In addition to providing insights into deep-sea hydrothermal vent biogeochemistry, the methods described herein also offer a practical approach for the incubation of any deep-sea pelagic sample under in situ conditions.
BibTeX:
@article{McNichol2016a,
  author = {McNichol, J and Sylva, S P and Thomas, F and Taylor, C D and Sievert, S M and Seewald, J S},
  title = {Assessing microbial processes in deep-sea hydrothermal systems by incubation at in situ temperature and pressure},
  journal = {Deep Sea Research Part I: Oceanographic Research Papers},
  year = {2016},
  volume = {115},
  pages = {221--232},
  doi = {10.1016/j.dsr.2016.06.011}
}
Medagoda L, Williams SB, Pizarro O, Kinsey JC and Jakuba MV (2016), "Mid-water current aided localization for autonomous underwater vehicles", Autonomous Robots. Vol. 40(7, SI), pp. 1207-1227.
Abstract: Survey-class autonomous underwater vehicles (AUVs) typically rely on Doppler Velocity Logs (DVL) for precision localization near the seafloor. In cases where the seafloor depth is greater than the DVL bottom-lock range, localizing between the surface and the seafloor presents a localization problem since both GPS and DVL observations are unavailable in the mid-water column. This work proposes a solution to this problem that exploits the fact that current profile layers of the water column are near constant over short time scales (in the scale of minutes). Using observations of these currents obtained with the Acoustic Doppler Current Profiler mode of the DVL during descent, along with data from other sensors, the method discussed herein constrains position error. The method is validated using field data from the Sirius AUV coupled with view-based Simultaneous Localization and Mapping (SLAM) and on descents up to 3km deep with the Sentry AUV.
BibTeX:
@article{Medagoda2016,
  author = {Medagoda, L and Williams, S B and Pizarro, O and Kinsey, J C and Jakuba, M V},
  title = {Mid-water current aided localization for autonomous underwater vehicles},
  journal = {Autonomous Robots},
  year = {2016},
  volume = {40},
  number = {7, SI},
  pages = {1207--1227},
  doi = {10.1007/s10514-016-9547-3}
}
Mevenkamp L, Van Campenhout J and Vanreusel A (2016), "Experimental evidence for selective settlement of meiofauna from two distinct environments after sediment suspension", Journal of Experimental Marine Biology and Ecology. Vol. 474, pp. 195-203.
Abstract: The cosmopolitan distribution of many meiofaunal organisms raises questions about their dispersal. The small size and the lack of a planktonic life stage of most meiofauna taxa including free-living nematodes suggest that passive dispersal is a main factor determining their distribution. This study investigates the settling behaviour of meiofauna in a water column under no-flow conditions. Two ex situ settling experiments were conducted with (1) macrophyte associated meiofauna from an intertidal salt marsh and (2) meiofauna of sulphidic sediments associated with bacterial mats from the deep-sea Håkon Mosby mud volcano. Cilyndrical containers filled with sieved seawater were used as settling chambers and five different substrates, placed on the bottom of the containers, were offered to the descending meiofaunal assemblage. The substrates used in experiment 1 were agar with bacteria, agar with Fucus spiralis, sulphidic agar medium, bare agar and an empty Petri dish. For experiment 2 azoic sediment with algae, azoic sediment with bacteria, a sulphidic medium, bare azoic sediment and an empty Petri dish were used. The intertidal experiment revealed that nematodes and nauplius larvae showed four- to tenfold higher densities in the Fucus treatment compared with the controls whereas deep-sea nematode and harpacticoid copepod densities in the sulphide treatment were more than three times higher compared with all other treatments. In both experiments nematode composition did not differ from the reference samples whereas proportions of harpacticoid copepods were increased in the treatments of the deep-sea experiment compared with the reference sample suggesting a better ability to select settlement sites than nematodes. In both experiments meiofauna abundance was highest in substrates with similar characteristics as their original habitat. These findings indicate that some meiofaunal organisms can selectively settle once they are suspended in the water column in the absence of water flow and therefore actively contribute to their dispersal at small spatial scales.
BibTeX:
@article{Mevenkamp2016,
  author = {Mevenkamp, L and Van Campenhout, J and Vanreusel, A},
  title = {Experimental evidence for selective settlement of meiofauna from two distinct environments after sediment suspension},
  journal = {Journal of Experimental Marine Biology and Ecology},
  year = {2016},
  volume = {474},
  pages = {195--203},
  doi = {10.1016/j.jembe.2015.10.005}
}
Mittelstaedt E, Fornari DJ, Crone TJ, Kinsey JC, Kelley DS and Elend MJ (2016), "Diffuse venting at the ASHES hydrothermal field: Heat flux and tidally modulated flow variability derived from in situ time-series measurements", Geochemistry, Geophysics, Geosystems. Vol. 17, pp. 1435-1453.
Abstract: Time-series measurements of diffuse exit-fluid temperature and velocity collected with a new, deep-sea camera, and temperature measurement system, the Diffuse Effluent Measurement System (DEMS), were examined from a fracture network within the ASHES hydrothermal field located in the caldera of Axial Seamount, Juan de Fuca Ridge. The DEMS was installed using the HOV Alvin above a fracture near the Phoenix vent. The system collected 20 s of 20 Hz video imagery and 24 s of 1 Hz temperature measurements each hour between 22 July and 2 August 2014. Fluid velocities were calculated using the Diffuse Fluid Velocimetry (DFV) technique. Over the similar to 12 day deployment, median upwelling rates and mean fluid temperature anomalies ranged from 0.5 to 6 cm/s and 0 degrees C to similar to 6.5 degrees C above ambient, yielding a heat flux of 0.29 +/- 0.22 MW M-2 and heat output of 3.1 +/- 2.5 kW. Using a photo mosaic to measure fracture dimensions, the total diffuse heat output from cracks across ASHES field is estimated to be 2.05 +/- 1.95 MW. Variability in temperatures and velocities are strongest at semidiurnal periods and show significant coherence with tidal height variations. These data indicate that periodic variability near Phoenix vent is modulated both by tidally controlled bottom currents and seafloor pressure, with seafloor pressures being the dominant influence. These results emphasize the importance of local permeability on diffuse hydrothermal venting at mid-ocean ridges and the need to better quantify heat flux associated with young oceanic crust.
BibTeX:
@article{Mittelstaedt2016,
  author = {Mittelstaedt, E and Fornari, D J and Crone, T J and Kinsey, J C and Kelley, D S and Elend, M J},
  title = {Diffuse venting at the ASHES hydrothermal field: Heat flux and tidally modulated flow variability derived from in situ time-series measurements},
  journal = {Geochemistry, Geophysics, Geosystems},
  year = {2016},
  volume = {17},
  pages = {1435--1453},
  doi = {10.1002/2015GC006144}
}
Neira NM, Clark JF, Fisher AT, Wheat CG, Haymon RM and Becker K (2016), "Cross-hole tracer experiment reveals rapid fluid flow and low effective porosity in the upper oceanic crust", Earth and Planetary Science Letters. Vol. 450, pp. 355-365.
Abstract: Numerous field, laboratory, and modeling studies have explored the flows of fluid, heat, and solutes during seafloor hydrothermal circulation, but it has been challenging to determine transport rates and flow directions within natural systems. Here we present results from the first cross-hole tracer experiment in the upper oceanic crust, using four subseafloor borehole observatories equipped with autonomous samplers to track the transport of a dissolved tracer (sulfur hexafluoride, SF6) injected into a ridge-flank hydrothermal system. During the first three years after tracer injection, SF6 was transported both north and south through the basaltic aquifer. The observed tracer transport rate of ∼2–3 m/day is orders of magnitude greater than bulk rates of flow inferred from thermal and chemical observations and calculated with coupled fluid-heat flow simulations. Taken together, these results suggest that the effective porosity of the upper volcanic crust through which much tracer was transported is textless1%, with fluid flowing rapidly along a few well-connected channels. This is consistent with the heterogeneous (layered, faulted, and/or fractured) nature of the volcanic upper oceanic crust.
BibTeX:
@article{Neira2016,
  author = {Neira, N M and Clark, J F and Fisher, A T and Wheat, C G and Haymon, R M and Becker, K},
  title = {Cross-hole tracer experiment reveals rapid fluid flow and low effective porosity in the upper oceanic crust},
  journal = {Earth and Planetary Science Letters},
  year = {2016},
  volume = {450},
  pages = {355--365},
  doi = {10.1016/j.epsl.2016.06.048}
}
Prouty NG, Fisher CR, Demopoulos AWJ and Druffel ERM (2016), "Growth rates and ages of deep-sea corals impacted by the Deepwater Horizon oil spill", Deep Sea Research Part II: Topical Studies in Oceanography. Vol. 129, pp. 196-212.
Abstract: The impact of the April 2010 Deepwater Horizon (DWH) spill on deep-sea coral communities in the Gulf of Mexico (GoM) is still under investigation, as is the potential for these communities to recover. Impacts from the spill include observation of corals covered with flocculent material, with bare skeleton, excessive mucous production, sloughing tissue, and subsequent colonization of damaged areas by hydrozoans. Information on growth rates and life spans of deep-sea corals is important for understanding the vulnerability of these ecosystems to both natural and anthropogenic perturbations, as well as the likely duration of any observed adverse impacts. We report radiocarbon ages and radial and linear growth rates based on octocorals (Paramuricea spp. and Chrysogorgia sp.) collected in 2010 and 2011 from areas of the DWH impact. The oldest coral radiocarbon ages were measured on specimens collected 11 km to the SW of the oil spill from the Mississippi Canyon (MC) 344 site: 599 and 55 cal yr BP, suggesting continuous life spans of over 600 years for Paramuricea biscaya, the dominant coral species in the region. Calculated radial growth rates, between 0.34 μm yr−1 and 14.20 μm yr−1, are consistent with previously reported proteinaceous corals from the GoM. Anomalously low radiocarbon (Δ14C) values for soft tissue from some corals indicate that these corals were feeding on particulate organic carbon derived from an admixture of modern surface carbon and a low 14C carbon source. Results from this work indicate fossil carbon could contribute 5–10% to the coral soft tissue Δ14C signal within the area of the spill impact. The influence of a low 14C carbon source (e.g., petro-carbon) on the particulate organic carbon pool was observed at all sites within 30 km of the spill site, with the exception of MC118, which may have been outside of the dominant northeast–southwest zone of impact. The quantitatively assessed extreme longevity and slow growth rates documented here highlight the vulnerability of these long-lived deep sea coral species to disturbance.
BibTeX:
@article{Prouty2016,
  author = {Prouty, N G and Fisher, C R and Demopoulos, A W J and Druffel, E R M},
  title = {Growth rates and ages of deep-sea corals impacted by the Deepwater Horizon oil spill},
  journal = {Deep Sea Research Part II: Topical Studies in Oceanography},
  year = {2016},
  volume = {129},
  pages = {196--212},
  doi = {10.1016/j.dsr2.2014.10.021}
}
Prouty NG, Sahy D, Ruppel CD, Roark EB, Condon D, Brooke S, Ross SW and Demopoulos AWJ (2016), "Insights into methane dynamics from analysis of authigenic carbonates and chemosynthetic mussels at newly-discovered Atlantic Margin seeps", Earth and Planetary Science Letters. Vol. 449, pp. 332-344.
Abstract: The recent discovery of active methane venting along the US northern and mid-Atlantic margin represents a new source of global methane not previously accounted for in carbon budgets from this region. However, uncertainty remains as to the origin and history of methane seepage along this tectonically inactive passive margin. Here we present the first isotopic analyses of authigenic carbonates and methanotrophic deep-sea mussels, Bathymodiolus sp., and the first direct constraints on the timing of past methane emission, based on samples collected at the upper slope Baltimore Canyon (∼385 m water depth) and deepwater Norfolk (∼1600 m) seep fields within the area of newly-discovered venting. The authigenic carbonates at both sites were dominated by aragonite, with an average View the MathML sourceδC13 signature of −47‰−47‰, a value consistent with microbially driven anaerobic oxidation of methane-rich fluids occurring at or near the sediment–water interface. Authigenic carbonate U and Sr isotope data further support the inference of carbonate precipitation from seawater-derived fluids rather than from formation fluids from deep aquifers. Carbonate stable and radiocarbon (View the MathML sourceδC13 and View the MathML sourceΔC13) isotope values from living Bathymodiolus sp. specimens are lighter than those of seawater dissolved inorganic carbon, highlighting the influence of fossil carbon from methane on carbonate precipitation. U–Th dates on authigenic carbonates suggest seepage at Baltimore Canyon between 14.7±0.6 ka14.7±0.6 ka to 15.7±1.6 ka15.7±1.6 ka, and at the Norfolk seep field between 1.0±0.7 ka1.0±0.7 ka to 3.3±1.3 ka3.3±1.3 ka, providing constraint on the longevity of methane efflux at these sites. The age of the brecciated authigenic carbonates and the occurrence of pockmarks at the Baltimore Canyon upper slope could suggest a link between sediment delivery during Pleistocene sea-level lowstand, accumulation of pore fluid overpressure from sediment compaction, and release of overpressure through subsequent venting. Calculations show that the Baltimore Canyon site probably has not been within the gas hydrate stability zone (GHSZ) in the past 20 ka, meaning that in-situ release of methane from dissociating gas hydrate cannot be sustaining the seep. We cannot rule out updip migration of methane from dissociation of gas hydrate that occurs farther down the slope as a source of the venting at Baltimore Canyon, but consider that the history of rapid sediment accumulation and overpressure may play a more important role in methane emissions at this site.
BibTeX:
@article{Prouty2016a,
  author = {Prouty, N G and Sahy, D and Ruppel, C D and Roark, E B and Condon, D and Brooke, S and Ross, S W and Demopoulos, A W J},
  title = {Insights into methane dynamics from analysis of authigenic carbonates and chemosynthetic mussels at newly-discovered Atlantic Margin seeps},
  journal = {Earth and Planetary Science Letters},
  year = {2016},
  volume = {449},
  pages = {332--344},
  doi = {10.1016/j.epsl.2016.05.023}
}
Radice VZ, Quattrini AM, Wareham VE, Edinger EN and Cordes EE (2016), "Vertical water mass structure in the North Atlantic influences the bathymetric distribution of species in the deep-sea coral genus Paramuricea", Deep Sea Research Part I: Oceanographic Research Papers. Vol. 116, pp. 253-263.
Abstract: Deep-sea corals are the structural foundation of their ecosystems along continental margins worldwide, yet the factors driving their broad distribution are poorly understood. Environmental factors, especially depth-related variables including water mass properties, are thought to considerably affect the realized distribution of deep-sea corals. These factors are governed by local and regional oceanographic conditions that directly influence the dispersal of larvae, and therefore affect the ultimate distribution of adult corals. We used molecular barcoding of mitochondrial and nuclear sequences to identify species of octocorals in the genus Paramuricea collected from the Labrador Sea to the Grand Banks of Newfoundland, Canada at depths of 150–1500 m. The results of this study revealed overlapping bathymetric distributions of the Paramuricea species present off the eastern Canadian coast, including the presence of a few cryptic species previously designated as Paramuricea placomus. The distribution of Paramuricea species in the western North Atlantic differs from the Gulf of Mexico, where five Paramuricea species exhibit strong segregation by depth. The different patterns of Paramuricea species in these contrasting biogeographic regions provide insight into how water mass structure may shape species distribution. Investigating Paramuricea prevalence and distribution in conjunction with oceanographic conditions can help demonstrate the factors that generate and maintain deep-sea biodiversity.
BibTeX:
@article{Radice2016,
  author = {Radice, V Z and Quattrini, A M and Wareham, V E and Edinger, E N and Cordes, E E},
  title = {Vertical water mass structure in the North Atlantic influences the bathymetric distribution of species in the deep-sea coral genus Paramuricea},
  journal = {Deep Sea Research Part I: Oceanographic Research Papers},
  year = {2016},
  volume = {116},
  pages = {253--263},
  doi = {10.1016/j.dsr.2016.08.014}
}
Raven MR, Sessions AL, Fischer WW and Adkins JF (2016), "Sedimentary pyrite δ34S differs from porewater sulfide in Santa Barbara Basin: Proposed role of organic sulfur", Geochimica et Cosmochimica Acta. Vol. 186, pp. 120-134.
Abstract: Santa Barbara Basin sediments host a complex network of abiotic and metabolic chemical reactions that knit together the carbon, sulfur, and iron cycles. From a 2.1-m sediment core collected in the center of the basin, we present high-resolution profiles of the concentrations and isotopic compositions of all the major species in this system: sulfate, sulfide (∑H2S), elemental sulfur (S0), pyrite, extractable organic sulfur (OS), proto-kerogen S, total organic and dissolved inorganic carbon, and total and reducible iron. Below 10 cm depth, the core is characterized by low apparent sulfate reduction rates (textless0.01 mM/yr) except near the sulfate-methane transition zone. Surprisingly, pyrite forming in shallow sediments is ∼30‰ more 34S-depleted than coexisting ∑H2S in porewater. S0 has the same strongly 34S-depleted composition as pyrite where it forms near the sediment–water interface, though not at depth. This pattern is not easily explained by conventional hypotheses in which sedimentary pyrite derives from abiotic reactions with porewater ∑H2S or from the products of S0 disproportionation. Instead, we propose that pyrite formation in this environment occurs within sulfate reducing microbial aggregates or biofilms, where it reflects the isotopic composition of the immediate products of bacterial sulfate reduction. Porewater ∑H2S in Santa Barbara Basin may be more 34S-enriched than pyrite due to equilibration with relatively 34S-enriched OS. The difference between OS and pyrite δ34S values would then reflect the balance between microbial sulfide formation and the abundance of exchangeable OS. Both OS and pyrite δ34S records thus have the potential to provide valuable information about biogeochemical cycles and redox structure in sedimentary paleoenvironments.
BibTeX:
@article{Raven2016,
  author = {Raven, M R and Sessions, A L and Fischer, W W and Adkins, J F},
  title = {Sedimentary pyrite δ34S differs from porewater sulfide in Santa Barbara Basin: Proposed role of organic sulfur},
  journal = {Geochimica et Cosmochimica Acta},
  year = {2016},
  volume = {186},
  pages = {120--134},
  doi = {10.1016/j.gca.2016.04.037}
}
Rouxel OJ, Toner BM, Manganini SJ and German CR (2016), "Geochemistry and iron isotope systematics of hydrothermal plume fall-out at East Pacific Rise 9°50′N", Chemical Geology. Vol. 441, pp. 212-234.
Abstract: While gross hydrothermal fluxes entering the ocean are known to be significant, much remains unknown about the fate of this material as it disperses through the oceans, and its impact upon ocean biogeochemistry. Mineral precipitation within hydrothermal plumes removes hydrothermally-sourced metals from solution and also acts to scavenge trace elements from the surrounding water column. Here, we investigate the fate of particulate Fe released from high-temperature hydrothermal venting at EPR 9°50′N and its potential impact on local deep-ocean Fe-isotopic and geochemical budgets. We measured the geochemical composition, mineralogy and Fe isotope systematics of hydrothermal plume products in order to determine whether mineral precipitation imposes characteristic Fe-isotope “fingerprints” for hydrothermally sourced Fe in the deep ocean. Our sampling includes sediment trap deployments after the eruptive event of Jan. 2006, allowing the examination of temporal changes of hydrothermal fluxes over a 160 day period. Results show that Fe isotope composition in the high-temperature vent fluids is rather constant over the sampling period 2004–2008, and that secular variations of δ56Fe values of plume particles from − 0.03 to − 0.91‰ (relative to IRMM-14 standard) could be explained by local processes leading to variable mixing extents of hydrothermal, biogenic and lithogenic particles. Through geochemical modeling, we have calculated the relative abundances of hydrothermal plume components such as sulfides, Fe oxyhydroxides, organic matter, biogenic and lithogenic phases. We demonstrate that Fe isotope fractionation in the hydrothermal plume occurs during the formation and rapid settling of Fe-sulfides that are characterized by δ56Fe values ranging from − 0.73 ± 0.13‰ to − 0.86 ± 0.13‰, which is systematically lower than the end-member hydrothermal fluids (δ56Fe = − 0.4‰). This study suggests that both the initial Fe isotope composition of the high-temperature vent fluids and its initial Fe/H2S ratio (i.e. Fe-sulfide precipitation versus Fe-oxyhydroxide precipitation) should impose characteristic Fe isotope “fingerprints” for hydrothermally derived Fe in the deep ocean.
BibTeX:
@article{Rouxel2016,
  author = {Rouxel, O J and Toner, B M and Manganini, S J and German, C R},
  title = {Geochemistry and iron isotope systematics of hydrothermal plume fall-out at East Pacific Rise 9°50′N},
  journal = {Chemical Geology},
  year = {2016},
  volume = {441},
  pages = {212--234},
  doi = {10.1016/j.chemgeo.2016.08.027}
}
Salman-Carvalho V, Fadeev E, Joye SB and Teske AP (2016), "How Clonal Is Clonal? Genome Plasticity across Multicellular Segments of a "Candidatus Marithrix sp." Filament from Sulfidic, Briny Seafloor Sediments in the Gulf of Mexico", Frontiers in Microbiology. Vol. 7, pp. 1173.
Abstract: "Candidatus Marithrix" is a recently described lineage within the group of large sulfur bacteria (Beggiatoaceae, Gammaproteobacteria). This genus of bacteria comprises vacuolated, attached-living filaments that inhabit the sediment surface around vent and seep sites in the marine environment. A single filament is ca. 100 mu m in diameter, several millimeters long, and consists of hundreds of clonal cells, which are considered highly polyploid. Based on these characteristics, "Candidatus Marithrix" was used as a model organism for the assessment of genomic plasticity along segments of a single filament using next generation sequencing to possibly identify hotspots of microevolution. Using six consecutive segments of a single filament sampled from a mud volcano in the Gulf of Mexico, we recovered ca. 90% of the "Candidatus Marithrix" genome in each segment. There was a high level of genome conservation along the filament with average nucleotide identities between 99.98 and 100%. Different approaches to assemble all reads into a complete consensus genome could not fill the gaps. Each of the six segment datasets encoded merely a few hundred unique nucleotides and 5 or less unique genes the residual content was redundant in all datasets. Besides the overall high genomic identity, we identified a similar number of single nucleotide polymorphisms (SNPs) between the clonal segments, which are comparable to numbers reported for other clonal organisms. An increase of SNPs with greater distance of filament segments was not observed. The polyploidy of the cells was apparent when analyzing the heterogeneity of reads within a segment. Here, a strong increase in single nucleotide variants, or "intrasegmental sequence heterogeneity" (ISH) events, was observed. These sites may represent hotspots for genome plasticity, and possibly microevolution, since two thirds of these variants were not co-localized across the genome copies of the multicellular filament.
BibTeX:
@article{Salman-Carvalho2016,
  author = {Salman-Carvalho, V and Fadeev, E and Joye, S B and Teske, A P},
  title = {How Clonal Is Clonal? Genome Plasticity across Multicellular Segments of a "Candidatus Marithrix sp." Filament from Sulfidic, Briny Seafloor Sediments in the Gulf of Mexico},
  journal = {Frontiers in Microbiology},
  year = {2016},
  volume = {7},
  pages = {1173},
  doi = {10.3389/fmicb.2016.01173}
}
Simister RL, Antzis EW and White HK (2016), "Examining the diversity of microbes in a deep-sea coral community impacted by the Deepwater Horizon oil spill", Deep Sea Research Part II: Topical Studies in Oceanography. Vol. 129, pp. 157-166.
Abstract: Deep-sea surface sediments and flocculent material (floc) associated with corals containing oil originating from the Deepwater Horizon (DWH) oil spill were examined to determine the diversity of microbes and the presence of functional genes involved in oil degradation. For all samples, 16S rRNA clone libraries were constructed to obtain full-length sequences and Illumina amplicon sequencing was used to further probe the diversity of the microbial community. The 16S rRNA gene data obtained by Illumina amplicon sequencing revealed Proteobacteria (55–64%) as the dominant bacteria in both sediment and floc samples. The floc samples were comprised of mostly aerobic or facultative aerobic phylotypes including Rhizobiales, Rhodobacterales, Sphingomonadales, Rickettsiales, Alteromonadales, Pseudomonadales, whereas mixtures of the aforementioned aerobic species and anaerobic phylotypes such as Desulfobacterales, Desulfuromonadales and Desulfarculales were present in the sediment samples. Genera affiliated with oil-degrading bacteria were identified in both sediment and floc samples. To evaluate the potential of the microbial community to degrade oil, clone libraries were constructed for the alkB gene (one of the structural genes of alkane hydroxylase involved in the aerobic degradation of n-alkanes of chain length textgreaterC5–C16) and the alkylsuccinate synthase/benzylsuccinate synthases (assA/bssA) gene (involved in the anaerobic degradation of n-alkanes [via assA] and polycyclic aromatic hydrocarbons [PAHs; via bssA]). The alkB gene was present in all samples with the majority of sequences clustering to members of the Proteobacteria closely aligned to environmental sequences from hydrocarbon seep environments. The assA/bssA genes were only detected in sediment samples and were closely affiliated with δ-Proteobacteria previously detected in oil-contaminated sediments and oil-enrichment cultures. These data provide insight into the differences between environments impacted by the DWH oil spill and highlight the functional diversity of oil-degrading microbes associated with a deep-sea coral community.
BibTeX:
@article{Simister2016,
  author = {Simister, R L and Antzis, E W and White, H K},
  title = {Examining the diversity of microbes in a deep-sea coral community impacted by the Deepwater Horizon oil spill},
  journal = {Deep Sea Research Part II: Topical Studies in Oceanography},
  year = {2016},
  volume = {129},
  pages = {157--166},
  doi = {10.1016/j.dsr2.2015.01.010}
}
Tan CY, Ding K and Seyfried WE (2016), "Development and Application of a New Mobile pH Calibrator for Real-Time Monitoring of pH in Diffuse Flow Hydrothermal Vent Fluids", Marine Technology Society Journal. Vol. 50(2), pp. 37-47.
Abstract: In situ measurement of pH in diffuse flow hydrothermal vent fluids is necessary to investigate the feedback between geochemical and biochemical processes. Accurate pH determination has been unusually challenging owing to temperature and pressure effects that place severe constraints on the performance of a wide variety of pH sensor systems. In this paper, we describe a newly developed mobile pH calibrator (MpHC), which makes use of In situ calibration protocols that enhance the accuracy of pH measurement and monitoring on the ocean floor at deep-sea hydrothermal vents. The MpHC combines the physically robust and highly sensitive iridium solid-state pH electrode with a flow control system to perform 2-point calibration with on-board pH buffer solutions. The small size and novel design of the sensor probe allow more effective access to seafloor hydrothermal vent fluids and their associated sulfide structures and biological communities. The MpHC is capable of In situ deployment by submersible via ICL (inductively couple link) communication around hydrothermal vents at pressures and temperatures up to 45 MPa and 100 degrees C, respectively. In this paper, we also present results of In situ calibration methods used to correct the standard potential and slope (mV/pH) of the solid-state electrode for temperature effects. The MpHC has been deployed most recently using the submersible Alvin during cruise AT26-17 to Axial Seamount and Main Endeavour Field, Juan De Fuca Ridge in the NE Pacific. With In situ calibration functionality, the MpHC offers the prospect of more successful longer-term measurements in keeping with power availability provided by cabled seafloor observatories coming online in the NE Pacific.
BibTeX:
@article{Tan2016,
  author = {Tan, C Y and Ding, K and Seyfried, W E},
  title = {Development and Application of a New Mobile pH Calibrator for Real-Time Monitoring of pH in Diffuse Flow Hydrothermal Vent Fluids},
  journal = {Marine Technology Society Journal},
  year = {2016},
  volume = {50},
  number = {2},
  pages = {37--47}
}
Teske AP, de Beer D, McKay LJ, Tivey MK, Biddle JF, Hoer DR, Lloyd KG, Lever MA, Roy H, Albert DB, Mendlovitz HP and MacGregor BJ (2016), "The Guaymas Basin Hiking Guide to Hydrothermal Mounds, Chimneys, and Microbial Mats: Complex Seafloor Expressions of Subsurface Hydrothermal Circulation", Frontiers in Microbiology. Vol. 7, pp. 75.
Abstract: The hydrothermal mats, mounds, and chimneys of the southern Guaymas Basin are the surface expression of complex subsurface hydrothermal circulation patterns. In this overview, we document the most frequently visited features of this hydrothermal area with photographs, temperature measurements, and selected geochemical data; many of these distinct habitats await characterization of their microbial communities and activities. Microprofiler deployments on microbial mats and hydrothermal sediments show their steep geochemical and thermal gradients at millimeter-scale vertical resolution. Mapping these hydrothermal features and sampling locations within the southern Guaymas Basin suggest linkages to underlying shallow sills and heat flow gradients. Recognizing the inherent spatial limitations of much current Guaymas Basin sampling calls for comprehensive surveys of the wider spreading region.
BibTeX:
@article{Teske2016,
  author = {Teske, A P and de Beer, D and McKay, L J and Tivey, M K and Biddle, J F and Hoer, D R and Lloyd, K G and Lever, M A and Roy, H and Albert, D B and Mendlovitz, H P and MacGregor, B J},
  title = {The Guaymas Basin Hiking Guide to Hydrothermal Mounds, Chimneys, and Microbial Mats: Complex Seafloor Expressions of Subsurface Hydrothermal Circulation},
  journal = {Frontiers in Microbiology},
  year = {2016},
  volume = {7},
  pages = {75},
  doi = {10.3389/fmicb.2016.00075}
}
Thal J, Tivey MA, Yoerger DR and Bach W (2016), "Subaqueous cryptodome eruption, hydrothermal activity and related seafloor morphologies on the andesitic North Su volcano", Journal of Volcanology and Geothermal Research. Vol. 323, pp. 80-96.
Abstract: North Su is a double-peaked active andesite submarine volcano located in the eastern Manus Basin of the Bismarck Sea that reaches a depth of 1154 m. It hosts a vigorous and varied hydrothermal system with black and white smoker vents along with several areas of diffuse venting and deposits of native sulfur. Geologic mapping based on ROV observations from 2006 and 2011 combined with morphologic features identified from repeated bathymetric surveys in 2002 and 2011 documents the emplacement of a volcanic cryptodome between 2006 and 2011. We use our observations and rock analyses to interpret an eruption scenario where highly viscous, crystal-rich andesitic magma erupted slowly into the water-saturated, gravel-dominated slope of North Su. An intense fragmentation process produced abundant blocky clasts of a heterogeneous magma (olivine crystals within a rhyolitic groundmass) that only rarely breached through the clastic cover onto the seafloor. Phreatic and phreatomagmatic explosions beneath the seafloor cause mixing of juvenile and pre-existing lithic clasts and produce a volcaniclastic deposit. This volcaniclastic deposit consists of blocky, non-altered clasts next, variably (1–100%) altered clasts, hydrothermal precipitates and crystal fragments. The usually applied parameters to identify juvenile subaqueous lava fragments, i.e. fluidal shape or chilled margin, were not applicable to distinguish between pre-existing non-altered clasts and juvenile clasts. This deposit is updomed during further injection of magma and mechanical disruption. Gas-propelled turbulent clast-recycling causes clasts to develop variably rounded shapes. An abundance of blocky clasts and the lack of clasts typical for the contact of liquid lava with water is interpreted to be the result of a cooled, high-viscosity, crystal-rich magma that failed as a brittle solid upon stress. The high viscosity allows the lava to form blocky and short lobes. The pervasive volcaniclastic cover on North Su is partly cemented by hydrothermal precipitates. These hydrothermally-cemented breccias, crusts and single pillars show that hydrothermal circulation through a thick layer of volcaniclastic deposits can temporarily increase slope stability through precipitation and cementation.
BibTeX:
@article{Thal2016,
  author = {Thal, J and Tivey, M A and Yoerger, D R and Bach, W},
  title = {Subaqueous cryptodome eruption, hydrothermal activity and related seafloor morphologies on the andesitic North Su volcano},
  journal = {Journal of Volcanology and Geothermal Research},
  year = {2016},
  volume = {323},
  pages = {80--96},
  doi = {10.1016/j.jvolgeores.2016.04.041}
}
Thresher RE, Fallon SJ and Townsend AT (2016), "A “core-top” screen for trace element proxies of environmental conditions and growth rates in the calcite skeletons of bamboo corals (Isididae)", Geochimica et Cosmochimica Acta. Vol. 193, pp. 75-99.
Abstract: We test for trace element proxies in the high-magnesium calcite fraction of bamboo coral internodes by comparing environmental conditions and growth rates to the specimen-mean compositions of 73 corals that were live-caught at depths ranging from 3 to 3950 m and collected from habitats ranging from tropical coral reefs to the Antarctic slope. Comparisons were done at a large geographic scale (LGS) and for a well sampled area south of Australia, across depths at a single site, in order to help separate the effects of environmental variables that co-vary at one spatial scale, but not the other. Thirty-seven trace elements were measured using solution-based Sector Field ICP-MS, of which seventeen were significantly detected in more than a third of the specimens. Only eight element/calcium ratios correlated significantly with any environmental variable at the large geographic scale, and only four did so at the local level. At the LGS, the highest correlation was between ambient temperature and Mg/Ca, which accounted for 89% of the variance across specimens, spanned all four Isidid sub-families and was independently significant in the two best sampled sub-families. The predictive (geometric mean) relationship is View the MathML sourceT(°C)=-23.9(±2.46)+0.34(±0.25)Mg/Ca(mmol/mol) Turn MathJax on spanning a temperature range of −1.9 to 26.8 °C, Mg/Ca ratios from 58.6 to 155.1 mmol/mol, and an uncertainty (RMS) of 2.78 °C. The numbers in parentheses are 95% CIs. The slope of the regression does not differ significantly from that of abiotic high-Mg calcites, which suggests that the temperature-dependent incorporation of Mg into the carbonate results from kinetic reactions at the crystal surface. Analysis at the SH scale for the sub-set of specimens for which we had data suggests is also affected by growth rates. There were no obvious trace element correlates at either spatial scale of salinity or oxygen levels that could not be accounted for by covariance between these environmental parameters and, in most cases, temperature. Single and multiple correlation analyses also confirm previous suggestions that Ba/Ca in bamboo coral calcite is a proxy for seawater barium and hence refractory nutrients, suggest that Sr/Ca is influenced by specimen-mean Mg/Ca ratios and water temperature as well as possibly seawater Sr/Ca, and falsify for bamboo corals P/Ca (as well as P/Cd and Cd/Ca) as a proxy for seawater phosphate levels. The predictive relationship between Isidid skeletal-mean Ba/Ca and seawater silicate concentrations appears to be linear, and is given by View the MathML sourcesilicate(μmolkg-1)=-56.7(±20.8)+9217(±1632)Ba/Ca(mmol/mol) Turn MathJax on spanning a silicate range of 0.5 to 120 μmol kg−1, a Ba/Ca range of 0.0042 to 0.0195 mmol/mol, and with an uncertainty (RMS) of 33.1 μmol kg−1. Mn/Ca differences among specimens and sites are highly significant and appear to reflect seawater Mn, suggesting a proxy for this micronutrient. The compilation of growth rate data across 34 specimens indicates a wide range of growth rates even among con-familial specimens from within a single habitat, and suggests both ambient temperature and food availability underlie at least part of this variability.
BibTeX:
@article{Thresher2016,
  author = {Thresher, R E and Fallon, S J and Townsend, A T},
  title = {A “core-top” screen for trace element proxies of environmental conditions and growth rates in the calcite skeletons of bamboo corals (Isididae)},
  journal = {Geochimica et Cosmochimica Acta},
  year = {2016},
  volume = {193},
  pages = {75--99},
  doi = {10.1016/j.gca.2016.07.033}
}
Tontini FC, Crone TJ, de Ronde CEJ, Fornari DJ, Kinsey JC, Mittelstaedt E and Tivey MK (2016), "Crustal magnetization and the subseafloor structure of the ASHES vent field, Axial Seamount, Juan de Fuca Ridge: Implications for the investigation of hydrothermal sites", Geophysical Research Letters. Vol. 43, pp. 6205-6211.
Abstract: High-resolution geophysical data have been collected using the Autonomous Underwater Vehicle (AUV) Sentry over the ASHES (Axial Seamount Hydrothermal Emission Study) high-temperature (˜348°C) vent field at Axial Seamount, on the Juan de Fuca Ridge. Multiple surveys were performed on a 3-D grid at different altitudes above the seafloor, providing an unprecedented view of magnetic data resolution as a function of altitude above the seafloor. Magnetic data derived near the seafloor show that the ASHES field is characterized by a zone of low magnetization, which can be explained by hydrothermal alteration of the host volcanic rocks. Surface manifestations of hydrothermal activity at the ASHES vent field are likely controlled by a combination of local faults and fractures and different lava morphologies near the seafloor. Three-dimensional inversion of the magnetic data provides evidence of a vertical, pipe-like upflow zone of the hydrothermal fluids with a vertical extent of ˜100 m.
BibTeX:
@article{Tontini2016,
  author = {Tontini, F C and Crone, T J and de Ronde, C E J and Fornari, D J and Kinsey, J C and Mittelstaedt, E and Tivey, M K},
  title = {Crustal magnetization and the subseafloor structure of the ASHES vent field, Axial Seamount, Juan de Fuca Ridge: Implications for the investigation of hydrothermal sites},
  journal = {Geophysical Research Letters},
  year = {2016},
  volume = {43},
  pages = {6205--6211},
  doi = {10.1002/2016GL069430}
}
(2016), "Newly upgraded ROV Jason: Bigger and better", Ocean News & Technology. (May), pp. 42-43.
Abstract: A major, $2.4 million upgrade funded by the National Science Foundation has made the ROV Jason more capable than ever. This 12-month-long project, conducted by engineers at WHOI, which designed and built the vehicle, has increased the vehicle payload and range of activities and streamlined the vehicle operation. This is Jason's first upgrade of this magnitude since its second-generation launch in 2002; the original Jason was launched in 1988. The ROV is operated by WHOI for the nation's ocean scientists as part of the National Deep Submergence Facility. The upgrade has other added benefits as well. The heavy lift capability will be used at seafloor sites where several-hundred-meters-long sensor strings are routinely deployed into and recovered from seafloor bore holes.
BibTeX:
@article{,,
  title = {Newly upgraded ROV Jason: Bigger and better},
  journal = {Ocean News & Technology},
  year = {2016},
  number = {May},
  pages = {42--43}
}
Bemis KG, Silver D, Xu G, Light R, Jackson DR, Jones CD, Ozer S and Liu L (2015), "The path to COVIS: A review of acoustic imaging of hydrothermal flow regimes", Deep-Sea Research Part II: Topical Studies in Oceanography. Vol. 121, pp. 159-176.
Abstract: Acoustic imaging of hydrothermal flow regimes started with the incidental recognition of a plume on a routine sonar scan for obstacles in the path of the human-occupied submersible ALVIN. Developments in sonar engineering, acoustic data processing and scientific visualization have been combined to develop technology which can effectively capture the behavior of focused and diffuse hydrothermal discharge. This paper traces the development of these acoustic imaging techniques for hydrothermal flow regimes from their conception through to the development of the Cabled Observatory Vent Imaging Sonar (COVIS). COVIS has monitored such flow eight times a day for several years. Successful acoustic techniques for estimating plume entrainment, bending, vertical rise, volume flux, and heat flux are presented as is the state-of-the-art in diffuse flow detection.
BibTeX:
@article{Bemis2015,
  author = {Bemis, K G and Silver, D and Xu, G and Light, R and Jackson, D R and Jones, C D and Ozer, S and Liu, L},
  title = {The path to COVIS: A review of acoustic imaging of hydrothermal flow regimes},
  journal = {Deep-Sea Research Part II: Topical Studies in Oceanography},
  year = {2015},
  volume = {121},
  pages = {159--176},
  doi = {10.1016/j.dsr2.2015.06.002}
}
Bennett SA, Van Dover CL, Breier JA and Coleman ML (2015), "Effect of depth and vent fluid composition on the carbon sources at two neighboring deep-sea hydrothermal vent fields (Mid-Cayman Rise)", Deep-Sea Research Part I: Oceanographic Research Papers. Vol. 104, pp. 122-133.
Abstract: In this study, we have used stable isotopes of megafauna, microbial mats and particulate organic matter to examine the effect of depth and vent fluid composition on the carbon sources at two proximal, chemically distinct hydrothermal vent fields along the Mid-Cayman Rise. The basalt hosted Piccard vent field (4980 m) is twice as deep as the ultramafic hosted Von Damm vent field (2300 m) and has very different faunal assemblages. Of particular note is the presence of seep-associated fauna, Escarpia and Lamellibrachia tubeworms, at the Von Damm vent field. We identify a greater range of carbon sources and a suggestion of increased photosynthetic inputs to the Von Damm vent field compared to Piccard vent field. Rimicaris hybisae shrimp are the only abundant species shared between the two vent fields with δ13C values ranging between −22.7 and −10.1‰. Higher concentrations of hydrogen sulfide in the vent fluids at Piccard is proposed to be responsible for varying the relative contributions of the carbon fixation cycles used by their epibionts. Seep-associated fauna at Von Damm rely on elevated, thermogenic hydrocarbon content of the vent fluids for their carbon source (δ13C values ranging from −21.3 to 11.6‰). They also derive energy from hydrogen sulfide formed by the microbial reduction of sulfide (δ34S values ranging from −10.2 to −6.9‰). The tubeworms have very short roots (buried at most a centimeter into rubble), suggesting that microbial sulfate reduction must be occurring either in the shallow subsurface and/or in the anterior part of the tube. Overall, megafauna at Von Damm vent field appear to have a smaller food chain length (smaller δ15N range) but a greater breadth of trophic resources compared to the megafauna at the Piccard vent field.
BibTeX:
@article{Bennett2015,
  author = {Bennett, S A and Van Dover, C L and Breier, J A and Coleman, M L},
  title = {Effect of depth and vent fluid composition on the carbon sources at two neighboring deep-sea hydrothermal vent fields (Mid-Cayman Rise)},
  journal = {Deep-Sea Research Part I: Oceanographic Research Papers},
  year = {2015},
  volume = {104},
  pages = {122--133},
  doi = {10.1016/j.dsr.2015.06.005}
}
de Ronde CEJ, Chadwick WW, Ditchburn RG, Embley RW, Tunnicliffe V, Baker ET, Walker SL, Ferrini VL and Merle SM (2015), "Molten sulfur lakes of intraoceanic arc volcanoes", In Volcanic Lakes. Springer.
BibTeX:
@incollection{DeRonde2015,
  author = {de Ronde, C E J and Chadwick, W W and Ditchburn, R G and Embley, R W and Tunnicliffe, V and Baker, E T and Walker, S L and Ferrini, V L and Merle, S M},
  editor = {Rouwet, D},
  title = {Molten sulfur lakes of intraoceanic arc volcanoes},
  booktitle = {Volcanic Lakes},
  publisher = {Springer},
  year = {2015}
}
Escoube R, Rouxel OJ, Edwards KJ, Glazer B and Donard OFX (2015), "Coupled Ge/Si and Ge isotope ratios as geochemical tracers of seafloor hydrothermal systems: Case studies at Loihi Seamount and East Pacific Rise 9°50′N", Geochimica et Cosmochimica Acta. Vol. 167, pp. 93-112.
Abstract: Germanium (Ge) and Silicon (Si) exhibit similar geochemical behavior in marine environments but are variably enriched in seafloor hydrothermal fluids relative to seawater. In this study, Ge isotope and Ge/Si ratio systematics were investigated in low temperature hydrothermal vents from Loihi Seamount (Pacific Ocean, 18°54′N, 155°15′W) and results were compared to high-temperature vents from the East Pacific Rise (EPR) at 9°50′N. Loihi offers the opportunity to understand contrasting Ge and Si behavior in low temperature seafloor hydrothermal systems characterized by abundant Fe oxyhydroxide deposition at the seafloor. The results show that both Ge/Si and δ74/70Ge in hydrothermal fluids are fractionated relative to the basaltic host rocks. The enrichment in Ge vs. Si relative to fresh basalts, together with Ge isotope fractionation (Δ74/70Gefluid-basalt up to 1.15‰ at EPR 9°50′N and 1.64‰ at Loihi) are best explained by the precipitation of minerals (e.g. quartz and Fe-sulfides) during higher temperature seawater–rock reactions in the subsurface. The study of Fe-rich hydrothermal deposits at Loihi, largely composed of Fe-oxyhydroxides, shows that Ge isotopes are also fractionated upon mineral precipitation at the seafloor. We obtained an average Ge isotope fractionation factor between Fe-oxyhydroxide (ferrihydrite) and dissolved Ge in the fluid of −2.0 ± 0.6‰ (2sd), and a maximum value of −3.6 ± 0.6‰ (2sd), which is consistent with recent theoretical and experimental studies. The study of a hydrothermal chimney at Bio 9 vent at EPR 9°50′N also demonstrates that Ge isotopes are fractionated by approximately −5.6 ± 0.6‰ (2sd) during precipitation of metal sulfides under hydrothermal conditions. Using combined Ge/Si and estimated Ge isotope signatures of Ge sinks and sources in seawater, we propose a preliminary oceanic budget of Ge which reveals that an important sink, referred as the “missing Ge sink”, may correspond to Ge sequestration into authigenic Fe-oxyhydroxides in marine sediments. This study shows that combining Ge/Si and δ74/70Ge systematics provides a useful tool to trace hydrothermal Ge and Si sources in marine environments and to understand formation processes of seafloor hydrothermal deposits.
BibTeX:
@article{Escoube2015,
  author = {Escoube, R and Rouxel, O J and Edwards, K J and Glazer, B and Donard, O F X},
  title = {Coupled Ge/Si and Ge isotope ratios as geochemical tracers of seafloor hydrothermal systems: Case studies at Loihi Seamount and East Pacific Rise 9°50′N},
  journal = {Geochimica et Cosmochimica Acta},
  year = {2015},
  volume = {167},
  pages = {93--112},
  doi = {10.1016/j.gca.2015.06.025}
}
Faak K, Coogan LA and Chakraborty S (2015), "Near conductive cooling rates in the upper-plutonic section of crust formed at the East Pacific Rise", Earth and Planetary Science Letters. Vol. 423, pp. 36-47.
Abstract: A new geospeedometer, based on diffusion modeling of Mg in plagioclase, is used to determine cooling rates of the upper section of the lower oceanic crust formed at fast-spreading mid-ocean ridges. The investigated natural sample suites include gabbroic rocks formed at three different locations along the fast-spreading East Pacific Rise. These samples cover a depth interval of 0–840 m below the sheeted dike/gabbro boundary and therefore allow the variation of cooling rate as a function of depth within the upper plutonic sequence to be determined. We demonstrate that the cooling rates we obtained are robust (reproducible and consistent across different vertical sections at fast spreading ridges) and decrease significantly with increasing sample depth (covering almost 4 orders of magnitude, ranging from ∼1 °C y−1 for the shallowest samples to 0.0003 °C y−1 for the deepest samples). Both the absolute cooling rates, and the rate of decrease of cooling rate with depth, are consistent with conductive thermal models. In contrast, the absolute cooling rates determined from the deeper samples (textgreater300 m below DGB), and the large decrease in cooling rate with depth are inconsistent with thermal models that include substantial cooling by off-axis hydrothermal circulation within the upper plutonic section of the crust.
BibTeX:
@article{Faak2015,
  author = {Faak, K and Coogan, L A and Chakraborty, S},
  title = {Near conductive cooling rates in the upper-plutonic section of crust formed at the East Pacific Rise},
  journal = {Earth and Planetary Science Letters},
  year = {2015},
  volume = {423},
  pages = {36--47},
  doi = {10.1016/j.epsl.2015.04.025}
}
Findlay AJ, Gartman A, Shaw TJ and Luther GW (2015), "Trace metal concentration and partitioning in the first 1.5 m of hydrothermal vent plumes along the Mid-Atlantic Ridge: TAG, Snakepit, and Rainbow", Chemical Geology. Vol. 412, pp. 117-131.
Abstract: To determine the significance of metal fluxes from hydrothermal vents, understanding the speciation, reactivity, and possible transformations of metals and metal sulfides within the hydrothermal plume is critical. In this study, we measure the concentration and partitioning of trace metals (Fe, Mn, Cu, Cd, Co, Pb, Ni) and sulfide phases within the first 1.5 m of the rising plume at three vent fields (TAG, Snakepit, and Rainbow) along the Mid-Atlantic Ridge. A HCl/HNO3 leaching method was used to differentiate metals present in metal mono-sulfides from those in pyrite and chalcopyrite. At all three vent sites, Mn and Fe are primarily in the textless 0.2 μm (filtered) portion, whereas Cu, Co, Cd, and Pb are mainly in the unfiltered fraction. Significant concentrations of HNO3-extractable metals were found in the textless 0.2 μm fraction at all three vent sites, indicating that they likely exist in a recalcitrant nanoparticulate phase such as pyrite or chalcopyrite. At TAG and Snakepit, Cu is correlated with Co, as Co enters into chalcopyrite and other CuFeS phases and Zn is correlated with Cd and Pb as they form discrete metal sulfide phases. At Rainbow, Zn, Cd, and Pb are correlated, but Cu and Co are not correlated. The Rainbow data are consistent with the higher metal to sulfide ratio found at Rainbow. These speciation differences are significant as both mineral type and size will affect the amount of metal transported from the vent site and its availability for biogeochemical processes.
BibTeX:
@article{Findlay2015,
  author = {Findlay, A J and Gartman, A and Shaw, T J and Luther, G W},
  title = {Trace metal concentration and partitioning in the first 1.5 m of hydrothermal vent plumes along the Mid-Atlantic Ridge: TAG, Snakepit, and Rainbow},
  journal = {Chemical Geology},
  year = {2015},
  volume = {412},
  pages = {117--131},
  doi = {10.1016/j.chemgeo.2015.07.021}
}
Germanovich LN, Hurt RS, Smith JE, Genc G and Lowell RP (2015), "Measuring fluid flow and heat output in seafloor hydrothermal environments", Journal of Geophysical Research: Solid Earth. Vol. 120, pp. 8031-8055.
Abstract: We review techniques for measuring fluid flow and advective heat output from seafloor hydrothermal systems and describe new anemometer and turbine flowmeter devices we have designed, built, calibrated, and tested. These devices allow measuring fluid velocity at high-and low-temperature focused and diffuse discharge sites at oceanic spreading centers. The devices perform at ocean floor depths and black smoker temperatures and can be used to measure flow rates ranging over 2 orders of magnitude. Flow velocity is determined from the rotation rate of the rotor blades or paddle assembly. These devices have an open bearing design that eliminates clogging by particles or chemical precipitates as the fluid passes by the rotors. The devices are compact and lightweight enough for deployment from either an occupied or remotely operated submersible. The measured flow rates can be used in conjunction with vent temperature or geochemical measurements to obtain heat outputs or geochemical fluxes from both vent chimneys and diffuse flow regions. The devices have been tested on 30 Alvin dives on the Juan de Fuca Ridge and 3 Jason dives on the East Pacific Rise (EPR). We measured an anomalously low entrainment coefficient (0.064) and report 104 new measurements over a wide range of discharge temperatures (5 degrees-363 degrees C), velocities (2-199 cm/s), and depths (1517-2511 m). These include the first advective heat output measurements at the High Rise vent field and the first direct fluid flow measurement at Middle Valley. Our data suggest that black smoker heat output at the Main Endeavour vent field may have declined since 1994 and that after the 2005-2006 eruption, the high-temperature advective flow at the EPR 9 degrees 50'N field may have become more channelized, predominately discharging through the Bio 9 structure. We also report 16 measurements on 10 Alvin dives and 2 Jason dives with flow meters that predate devices described in this work and were used in the process of their development. This includes the first advective measurements in the Lau Basin and at the EPR 9 degrees 39.5'N. We discuss potential error sources and how they may affect the accuracy of measurements by our devices and other devices. In particular, we use the turbulent plume theory to evaluate the effect of entrainment of ambient seawater.
BibTeX:
@article{Germanovich2015,
  author = {Germanovich, L N and Hurt, R S and Smith, J E and Genc, G and Lowell, R P},
  title = {Measuring fluid flow and heat output in seafloor hydrothermal environments},
  journal = {Journal of Geophysical Research: Solid Earth},
  year = {2015},
  volume = {120},
  pages = {8031--8055},
  doi = {10.1002/2015JB012245}
}
Govenar BW, Fisher CR and Shank TM (2015), "Variation in the diets of hydrothermal vent gastropods", Deep-Sea Research Part II: Topical Studies in Oceanography. Vol. 121, pp. 193-201.
Abstract: A prevailing paradigm of hydrothermal vent ecology is that primary consumers feed on chemoautotrophic bacteria. However, for the purposes of reconstructing vent food webs and for tracking energy flow from the generation of rock and fluid chemistry through primary/ secondary productivity and consumption to the overlying water column, it remains unclear which consumers feed on which bacteria. In paired analyses of carbon and nitrogen tissue stable isotope values with unique 16S rRNA sequences from the stomach contents, we determined that two species of gastropod grazers appear to feed on epsilon-proteobacteria, while two other species have more diverse diets, including one species that consumes alpha-proteobacteria, planctomycetes, and non-green sulfur bacteria. Different carbon fixation pathways used by epsilon- and alpha-proteobacteria may account for the variation in the carbon stable isotope values among the consumers. Furthermore, our results indicate that trophic specialization and niche partitioning may contribute to the distribution and abundance of vent-endemic gastropods and support the hypothesis that consumers in the warmer habitats commonly feed on epsilon-proteobacteria that use the rTCA cycle, while in the cooler habitats they feed on additional bacteria that use the CBB cycle. These results suggest that the phylogenetic and metabolic diversity of free-living bacteria may play an important and previously overlooked role in facilitating species coexistence among primary consumers at hydrothermal vents and other chemosynthesis-based ecosystems.
BibTeX:
@article{Govenar2015,
  author = {Govenar, B W and Fisher, C R and Shank, T M},
  title = {Variation in the diets of hydrothermal vent gastropods},
  journal = {Deep-Sea Research Part II: Topical Studies in Oceanography},
  year = {2015},
  volume = {121},
  pages = {193--201},
  doi = {10.1016/j.dsr2.2015.06.021}
}
Greene JA, Tominaga M and Blackman DK (2015), "Geologic implications of seafloor character and carbonate lithification imaged on the domal core of Atlantis Massif", Deep-Sea Research Part II: Topical Studies in Oceanography. Vol. 121, pp. 246-255.
Abstract: We document the seafloor character on Atlantis Massif, an ocean core complex located at 30°N on the Mid-Atlantic Ridge, with an emphasis on the distribution of carbonate features. Seafloor imagery, near-bottom backscatter, and bathymetry were analyzed on the Central Dome and the Western Shoulder of the exposed footwall to the detachment, and on the Eastern Block, a hanging wall to the fault. We merged Argo II still images to produce photo-mosaics and evaluated these together with video imagery, acoustic reflectivity, and basic rock composition. The seafloor was classified as unconsolidated sediment, lithified carbonate crust, consolidated carbonate cap, exposed basement, or rubble, and the spatial distribution of each type was assessed. Unconsolidated sediment, exposed basement, and rubble were documented in all three regions studied. Lithified carbonate crust was also present on the Western Shoulder and eastern Central Dome. Consolidated carbonate cap was found on the Eastern Block. The formation of the carbonate rock is interpreted to reflect precipitation and/or sediment cementation via fluids derived from serpentinization. Both processes occur at the nearby Lost City Hydrothermal Field. The newly documented locations of seafloor carbonate lithification therefore mark pathways of past, possibly recent, fluid flux from subsurface water-rock reaction zones and represent an additional constituent of the carbon cycling hosted by oceanic lithosphere.
BibTeX:
@article{Greene2015,
  author = {Greene, J A and Tominaga, M and Blackman, D K},
  title = {Geologic implications of seafloor character and carbonate lithification imaged on the domal core of Atlantis Massif},
  journal = {Deep-Sea Research Part II: Topical Studies in Oceanography},
  year = {2015},
  volume = {121},
  pages = {246--255},
  doi = {10.1016/j.dsr2.2015.06.020}
}
Gulmann LK, Beaulieu SE, Shank TM, Ding K, Seyfried WE and Sievert SM (2015), "Bacterial diversity and successional patterns during biofilm formation on freshly exposed basalt surfaces at diffuse-flow deep-sea vents", Frontiers in Microbiology. Vol. 6, pp. 901.
Abstract: Many deep-sea hydrothermal vent systems are regularly impacted by volcanic eruptions, leaving fresh basalt where abundant animal and microbial communities once thrived. After an eruption, microbial biofilms are often the first visible evidence of biotic re-colonization. The present study is the first to investigate microbial colonization of newly exposed basalt surfaces in the context of vent fluid chemistry over an extended period of time (4–293 days) by deploying basalt blocks within an established diffuse-flow vent at the 9°50′ N vent field on the East Pacific Rise. Additionally, samples obtained after a recent eruption at the same vent field allowed for comparison between experimental results and those from natural microbial re-colonization. Over 9 months, the community changed from being composed almost exclusively of Epsilonproteobacteria to a more diverse assemblage, corresponding with a potential expansion of metabolic capabilities. The process of biofilm formation appears to generate similar surface-associated communities within and across sites by selecting for a subset of fluid-associated microbes, via species sorting. Furthermore, the high incidence of shared operational taxonomic units over time and across different vent sites suggests that the microbial communities colonizing new surfaces at diffuse-flow vent sites might follow a predictable successional pattern.
BibTeX:
@article{Gulmann2015,
  author = {Gulmann, L K and Beaulieu, S E and Shank, T M and Ding, K and Seyfried, W E and Sievert, S M},
  title = {Bacterial diversity and successional patterns during biofilm formation on freshly exposed basalt surfaces at diffuse-flow deep-sea vents},
  journal = {Frontiers in Microbiology},
  year = {2015},
  volume = {6},
  pages = {901},
  doi = {10.3389/fmicb.2015.00901}
}
Rouse GW, Wilson NG, Worsaae K and Vrijenhoek RC (2015), "A Dwarf Male Reversal in Bone-Eating Worms", CURRENT BIOLOGY., jan, 2015. Vol. 25(2), pp. 236-241.
Abstract: Darwin [1] hypothesized that sexes in a species should be similar
unless sexual selection, fecundity selection, or resource partitioning
has driven them apart. Male dwarfism has evolved multiple times in a
range of animals, raising questions about factors that drive such
extreme size dimorphism [2-4]. Ghiselin [5] noted that dwarf males
are more common among smaller marine animals, and especially among
sedentary and sessile species living at low densities, where mates are
difficult to find, or in deep-sea environments with limited energy
sources. These benefits of male dwarfism apply well to Osedax (Annelida:
Siboglinidae), bone-eating marine worms [6]. Osedax males, notable for
extreme sexual size dimorphism (SSD), are developmentally arrested
larvae that produce sperm from yolk reserves. Harems of dwarf males
reside in the lumen of the tube surrounding a female. Herein, we
describe Osedax priapus n. sp., a species that deviates remarkably by
producing males that anchor into, and feed on, bone via
symbiont-containing ``roots,'' just like female Osedax. Phylogenetic
analyses revealed O. priapus n. sp. as a derived species, and the
absence of dwarf males represents a character reversal for this genus.
Some dwarf male features are retained due to functional and
morphological constraints. Since O. priapus n. sp. males are anchored in
bone, they possess an extensible trunk that allows them to roam across
the bone to contact and inseminate females. Evolutionary and ecological
implications of a loss of male dwarfism are discussed.
BibTeX:
@article{ISI:000348129100027,
  author = {Rouse, Greg W and Wilson, Nerida G and Worsaae, Katrine and Vrijenhoek, Robert C},
  title = {A Dwarf Male Reversal in Bone-Eating Worms},
  journal = {CURRENT BIOLOGY},
  year = {2015},
  volume = {25},
  number = {2},
  pages = {236--241},
  doi = {10.1016/j.cub.2014.11.032}
}
Robador A, Jungbluth SP, LaRowe DE, Bowers RM, Rappe MS, Amend JP and Cowen JP (2015), "Activity and phylogenetic diversity of sulfate-reducing microorganisms in low-temperature subsurface fluids within the upper oceanic crust", FRONTIERS IN MICROBIOLOGY., jan, 2015. Vol. 5
Abstract: The basaltic ocean crust is the largest aquifer system on Earth, yet the
rates of biological activity in this environment are unknown.
Low-temperature (textless100 degrees C) fluid samples were investigated from
two borehole observatories in the Juan de Fuca Ridge (JFR) flank,
representing a range of upper oceanic basement thermal and geochemical
properties. Microbial sulfate reduction rates (SRR) were measured in
laboratory incubations with S-35-sulfate over a range of temperatures
and the identity of the corresponding sulfate-reducing microorganisms
(SRM) was studied by analyzing the sequence diversity of the functional
marker dissimilatory (bi)sulfite reductase (dsrAB) gene. We found that
microbial sulfate reduction was limited by the decreasing availability
of organic electron donors in higher temperature, more altered fluids.
Thermodynamic calculations indicate energetic constraints for
metabolism, which together with relatively higher cell-specific SRR
reveal increased maintenance requirements, consistent with novel
species-level dsrAB phylotypes of thermophilic SRM. Our estimates
suggest that microbially-mediated sulfate reduction may account for the
removal of organic matter in fluids within the upper oceanic crust and
underscore the potential quantitative impact of microbial processes in
deep subsurface marine crustal fluids on marine and global
biogeochemical carbon cycling.
BibTeX:
@article{ISI:000348807500001,
  author = {Robador, Alberto and Jungbluth, Sean P and LaRowe, Douglas E and Bowers, Robert M and Rappe, Michael S and Amend, Jan P and Cowen, James P},
  title = {Activity and phylogenetic diversity of sulfate-reducing microorganisms in low-temperature subsurface fluids within the upper oceanic crust},
  journal = {FRONTIERS IN MICROBIOLOGY},
  year = {2015},
  volume = {5},
  doi = {10.3389/fmicb.2014.00748}
}
Gollner S, Govenar B, Fisher CR and Bright M (2015), "Size matters at deep-sea hydrothermal vents: different diversity and habitat fidelity patterns of meio- and macrofauna", MARINE ECOLOGY PROGRESS SERIES., feb, 2015. Vol. 520, pp. 57-66.
Abstract: Species with markedly different sizes interact when sharing the same
habitat. Unravelling mechanisms that control diversity thus requires
consideration of a range of size classes. We compared patterns of
diversity and community structure for meio-and macrofaunal communities
sampled along a gradient of environmental stress at deep-sea
hydrothermal vents on the East Pacific Rise (9 degrees 50' N) and
neighboring basalt habitats. Both meio-and macrofaunal species
richnesses were lowest in the high-stress vent habitat, but macrofaunal
richness was highest among intermediate-stress vent habitats. Meiofaunal
species richness was negatively correlated with stress, and highest on
the basalt. In these deep-sea basalt habitats surrounding hydrothermal
vents, meiofaunal species richness was consistently higher than that of
macrofauna. Consideration of the physiological capabilities and life
history traits of different-sized animals suggests that different
patterns of diversity may be caused by different capabilities to deal
with environmental stress in the 2 size classes. In contrast to
meiofauna, adaptations of macrofauna may have evolved to allow them to
maintain their physiological homeostasis in a variety of hydrothermal
vent habitats and exploit this food-rich deep-sea environment in high
abundances. The habitat fidelity patterns also differed: macrofaunal
species occurred primarily at vents and were generally restricted to
this habitat, but meiofaunal species were distributed more evenly across
proximate and distant basalt habitats and were thus not restricted to
vent habitats. Over evolutionary time scales these contrasting patterns
are likely driven by distinct reproduction strategies and food demands
inherent to fauna of different sizes.
BibTeX:
@article{ISI:000349302600004,
  author = {Gollner, Sabine and Govenar, Breea and Fisher, Charles R and Bright, Monika},
  title = {Size matters at deep-sea hydrothermal vents: different diversity and habitat fidelity patterns of meio- and macrofauna},
  journal = {MARINE ECOLOGY PROGRESS SERIES},
  year = {2015},
  volume = {520},
  pages = {57--66},
  doi = {10.3354/meps11078}
}
Ross SW, Brooke S, Quattrini AM, Rhode M and Watterson JC (2015), "A deep-sea community, including Lophelia pertusa, at unusually shallow depths in the western North Atlantic Ocean off northeastern Florida", MARINE BIOLOGY., mar, 2015. Vol. 162(3), pp. 635-648.
Abstract: Living colonies of the cold-water scleractinian coral Lophelia pertusa
and other typically deep-water organisms were discovered in unusually
shallow depths (180-250 m) off northeastern Florida. Observations of L.
pertusa on rocky substrata and coral-built mounds represent the
shallowest records of large colonies of this coral in the western
Atlantic Ocean. Bioherms up to 30 m tall, extensive areas of eroded L.
pertusa rubble, and a well-developed cold-water community indicated that
these sites are long-term features, rather than short-term opportunistic
responses to temporary shifts in environmental conditions. Species that
are commonly observed on deeper reefs off the southeastern USA were
abundant at the shallow sites. The most abundant fishes on reef habitats
were Helicolenus dactylopterus, Laemonema barbatulum, Dysommina rugosa,
and Anthias spp. In addition to L. pertusa, the most common
macroinvertebrates on hard substrata were Eumunida picta, Chaceon
fenneri, octocorals, cup corals, and glass sponges. Bottom and
near-bottom temperatures (7-10 A degrees C) and nutrient concentrations
at the shallow sites were similar to those normally encountered at
500-600 m in this region. The shallow reef sites occur in an area known
for frequent Gulf Stream-driven upwelling of deep, nutrient-rich water.
However, the upwelling must be persistent or permanent in order to
maintain deep-sea communities at such shallow depths. Based on these
data, this area is under final review by the US Department of Commerce
for inclusion in one of the regional Coral Habitat Areas of Particular
Concern.
BibTeX:
@article{ISI:000349374800012,
  author = {Ross, Steve W and Brooke, Sandra and Quattrini, Andrea M and Rhode, Mike and Watterson, J Carter},
  title = {A deep-sea community, including Lophelia pertusa, at unusually shallow depths in the western North Atlantic Ocean off northeastern Florida},
  journal = {MARINE BIOLOGY},
  year = {2015},
  volume = {162},
  number = {3},
  pages = {635--648},
  doi = {10.1007/s00227-015-2611-2}
}
Colman A, Sinton JM and Wanless VD (2015), "Constraints from melt inclusions on depths of magma residence at intermediate magma supply along the Galapagos Spreading Center", EARTH AND PLANETARY SCIENCE LETTERS., feb, 2015. Vol. 412, pp. 122-131.
Abstract: Shallow, seismically imaged melt lenses are a ubiquitous feature of
mid-ocean ridges with high magma supply; melt lenses deepen and become
less continuous along axis as the rate of magma supply decreases.
Despite compelling petrologic evidence for evolution of magma within the
crust prior to eruption at lower magma supply, melt lenses are rarely
detected along ridge segments with rates of magma supply less than 0.3 x
10(6) m(3)/yr/km, and the depths of sub-axial magma reservoirs are
therefore poorly known. We use ion microprobe measurements of H2O and
CO2 concentrations of olivine-hosted melt inclusions to calculate vapor
saturation pressures that constrain crystallization depths at two
locations along the Galapagos Spreading Center (94.2 degrees W and 95
degrees W). These sites were chosen to examine crystallization pressures
in the presence (94.2 degrees W) and absence (95 degrees W) of a
seismically imaged melt lens. At 95 degrees W, where magma supply is too
low to sustain a seismically resolvable melt lens, samples were selected
from each of the three most recent eruptive units, allowing us to
document temporal variations in vapor saturation pressures and the depth
of magma residence at this location. Clusters in melt inclusion
entrapment depths for these eruptions range from 3.0 to 3.4 km below the
seafloor, indicating that magmas at 95 degrees W resided at a narrow
range of mid-crustal depths prior to eruption, generally consistent with
the global trend of increasing melt lens depth with decreasing rate of
magma supply. A discrepancy between seismic data and the peak in melt
inclusion entrapment depths at 94.2 degrees W may reflect temporal
variability of magmatic systems at this location. This study
demonstrates the potential for using measurements of the concentrations
of H2O and CO2 in olivine-hosted melt inclusions to determine the depths
of crustal magmatic systems that feed mid-ocean ridge eruptions, even in
locations where seismic studies have not detected melt lenses. (C) 2014
Elsevier B.V. All rights reserved.
BibTeX:
@article{ISI:000349424900014,
  author = {Colman, Alice and Sinton, John M and Wanless, V Dorsey},
  title = {Constraints from melt inclusions on depths of magma residence at intermediate magma supply along the Galapagos Spreading Center},
  journal = {EARTH AND PLANETARY SCIENCE LETTERS},
  year = {2015},
  volume = {412},
  pages = {122--131},
  doi = {10.1016/j.epsl.2014.12.007}
}
Burkett AM, Rathburn AE, Perez ME, Levin LA, Cha H and Rouse GW (2015), "Phylogenetic placement of Cibicidoides wuellerstorfi (Schwager, 1866) from methane seeps and non-seep habitats on the Pacific margin", GEOBIOLOGY., jan, 2015. Vol. 13(1), pp. 44-52.
Abstract: Benthic foraminifera are among the most abundant groups found in
deep-sea habitats, including methane seep environments. Unlike many
groups, no endemic foraminiferal species have been reported from methane
seeps, and to our knowledge, genetic data are currently sparse for
Pacific deep-sea foraminifera. In an effort to understand the
relationships between seep and non-seep populations of the deep-sea
foraminifera Cibicidoides wuellerstorfi, a common paleo-indicator
species, specimens from methane seeps in the Pacific were analyzed and
compared to one another for genetic similarities of small subunit rDNA
(SSU rDNA) sequences. Pacific Ocean C. wuellerstorfi were also compared
to those collected from other localities around the world (based on 18S
gene available on Genbank, e.g., Schweizer et al., 2009). Results from
this study revealed that C. wuellerstorfi living in seeps near Costa
Rica and Hydrate Ridge are genetically similar to one another at the
species level. Individuals collected from the same location that display
opposite coiling directions (dextral and sinstral) had no species level
genetic differences. Comparisons of specimens with genetic information
available from Genbank (SSU rDNA) showed that Pacific individuals,
collected for this study, are genetically similar to those previously
analyzed from the North Atlantic and Antarctic. These observations
provide strong evidence for the true cosmopolitan nature of C.
wuellerstorfi and highlight the importance of understanding how these
microscopic organisms are able to maintain sufficient genetic exchange
to remain within the same species between seep and non-seep habitats and
over global distances.
BibTeX:
@article{ISI:000350053000004,
  author = {Burkett, A M and Rathburn, A E and Perez, M E and Levin, L A and Cha, H and Rouse, G W},
  title = {Phylogenetic placement of Cibicidoides wuellerstorfi (Schwager, 1866) from methane seeps and non-seep habitats on the Pacific margin},
  journal = {GEOBIOLOGY},
  year = {2015},
  volume = {13},
  number = {1},
  pages = {44--52},
  doi = {10.1111/gbi.12118}
}
Plouviez S, Jacobson A, Wu M and Van Dover CL (2015), "Characterization of vent fauna at the Mid-Cayman Spreading Center", DEEP-SEA RESEARCH PART I-OCEANOGRAPHIC RESEARCH PAPERS., mar, 2015. Vol. 97, pp. 124-133.
Abstract: Hydrothermal vents in the deep sea have a global distribution on
mid-ocean ridges and comprise at least six biogeographic provinces. A
geographically isolated vent system was recently discovered on the
Mid-Cayman Spreading Center (MCSC). Here, we describe the faunal
assemblages associated with this system and their relationship to known
biogeographic provinces. Taxa from MCSC vents were sorted based on
morphology and barcoded using the cytochrome oxidase I (COI) and 16S
ribosomal RNA (16S) genes for identification. Distinct faunal
assemblages were recognized around vent chimneys at two hydrothermal
vent fields (Von Damm and Beebe) separated by a distance of similar to
13 km and textgreater 2.5-km depth along the Mid-Cayman Spreading Center. These
results suggest that depth and/or local conditions structure faunal
assemblages in this region. COI and microsatellite markers were then
used to explore the genetic structure of the shrimp Rimicaris hybisae,
the only abundant species shared between the shallow Von Damm and the
deep Beebe vent fields. R. hybisae was not genetically differentiated
between the Von Damm Spire and Beebe chimneys, suggesting this species
is better adapted for bathymetric dispersal and the differences in local
conditions than other MCSC species. In addition, a third faunal
assemblage dominated by two species of tubeworms was identified at Von
Damm in association with weakly diffuse flow sites (including the site
known as ``Marker X18''). The Marker X18 assemblage shares species
with seeps in the region. Fauna shared with both vents and seeps at the
MCSC reinforces the need for a global biogeographic study of deep-sea
chemosynthetic fauna that is not focused on specific habitats. (C) 2014
Elsevier Ltd. All rights reserved.
BibTeX:
@article{ISI:000350088800011,
  author = {Plouviez, Sophie and Jacobson, Alixandra and Wu, Mengyou and Van Dover, Cindy L},
  title = {Characterization of vent fauna at the Mid-Cayman Spreading Center},
  journal = {DEEP-SEA RESEARCH PART I-OCEANOGRAPHIC RESEARCH PAPERS},
  year = {2015},
  volume = {97},
  pages = {124--133},
  doi = {10.1016/j.dsr.2014.11.011}
}
Field EK, Sczyrba A, Lyman AE, Harris CC, Woyke T, Stepanauskas R and Emerson D (2015), "Genomic insights into the uncultivated marine Zetaproteobacteria at Loihi Seamount", ISME JOURNAL., apr, 2015. Vol. 9(4), pp. 857-870.
Abstract: The Zetaproteobacteria are a candidate class of marine iron-oxidizing
bacteria that are typically found in high iron environments such as
hydrothermal vent sites. As much remains unknown about these organisms
due to difficulties in cultivation, single-cell genomics was used to
learn more about this elusive group at Loihi Seamount. Comparative
genomics of 23 phylogenetically diverse single amplified genomes (SAGs)
and two isolates indicate niche specialization among the
Zetaproteobacteria may be largely due to oxygen tolerance and nitrogen
transformation capabilities. Only Form II ribulose 1,5-bisphosphate
carboxylase (RubisCO) genes were found in the SAGs, suggesting that some
of the uncultivated Zetaproteobacteria may be adapted to low oxygen
and/or high carbon dioxide concentrations. There is also genomic
evidence of oxygen-tolerant cytochrome c oxidases and oxidative
stress-related genes, indicating that others may be exposed to higher
oxygen conditions. The Zetaproteobacteria also have the genomic
potential for acquiring nitrogen from numerous sources including
ammonium, nitrate, organic compounds, and nitrogen gas. Two types of
molybdopterin oxidoreductase genes were found in the SAGs, indicating
that those found in the isolates, thought to be involved in iron
oxidation, are not consistent among all the Zetaproteobacteria. However,
a novel cluster of redox-related genes was found to be conserved in 10
SAGs as well as in the isolates warranting further investigation. These
results were used to isolate a novel iron-oxidizing Zetaproteobacteria.
Physiological studies and genomic analysis of this isolate were able to
support many of the findings from SAG analyses demonstrating the value
of these data for designing future enrichment strategies.
BibTeX:
@article{ISI:000351204900007,
  author = {Field, Erin K and Sczyrba, Alexander and Lyman, Audrey E and Harris, Christopher C and Woyke, Tanja and Stepanauskas, Ramunas and Emerson, David},
  title = {Genomic insights into the uncultivated marine Zetaproteobacteria at Loihi Seamount},
  journal = {ISME JOURNAL},
  year = {2015},
  volume = {9},
  number = {4},
  pages = {857--870},
  doi = {10.1038/ismej.2014.183}
}
Dziak RP, Bohnenstiehl DR, Baker ET, Matsumoto H, Caplan-Auerbach J, Embley RW, Merle SG, Walker SL, Lau T-K and Chadwick Jr. WW (2015), "Long-term explosive degassing and debris flow activity at West Mata submarine volcano", GEOPHYSICAL RESEARCH LETTERS., mar, 2015. Vol. 42(5), pp. 1480-1487.
Abstract: West Mata is a 1200m deep submarine volcano where explosive boninite
eruptions were observed in 2009. The acoustic signatures from the
volcano's summit eruptive vents Hades and Prometheus were recorded with
an in situ (similar to 25m range) hydrophone during ROV dives in May
2009 and with local (similar to 5km range) moored hydrophones between
December 2009 and August 2011. The sensors recorded low frequency
(1-40Hz), short duration explosions consistent with magma bubble bursts
from Hades, and broadband, 1-5min duration signals associated with
episodes of fragmentation degassing from Prometheus. Long-term eruptive
degassing signals, recorded through May 2010, preceded a several month
period of declining activity. Degassing episodes were not recorded
acoustically after early 2011, although quieter effusive eruption
activity may have continued. Synchronous optical measurements of
turbidity made between December 2009 and April 2010 indicate that
turbidity maxima resulted from occasional south flank slope failures
triggered by the collapse of accumulated debris during eruption
intervals.
BibTeX:
@article{ISI:000351847600028,
  author = {Dziak, R P and Bohnenstiehl, D R and Baker, E T and Matsumoto, H and Caplan-Auerbach, J and Embley, R W and Merle, S G and Walker, S L and Lau, T-K. and Chadwick Jr., W W},
  title = {Long-term explosive degassing and debris flow activity at West Mata submarine volcano},
  journal = {GEOPHYSICAL RESEARCH LETTERS},
  year = {2015},
  volume = {42},
  number = {5},
  pages = {1480--1487},
  doi = {10.1002/2014GL062603}
}
McCollom TM, Seewald JS and German CR (2015), "Investigation of extractable organic compounds in deep-sea hydrothermal vent fluids along the Mid-Atlantic Ridge", GEOCHIMICA ET COSMOCHIMICA ACTA., may, 2015. Vol. 156, pp. 122-144.
Abstract: The possibility that deep-sea hydrothermal vents may contain organic
compounds produced by abiotic synthesis or by microbial communities
living deep beneath the surface has led to numerous studies of the
organic composition of vent fluids. Most of these studies have focused
on methane and other light hydrocarbons, while the possible occurrence
of more complex organic compounds in the fluids has remained largely
unstudied. To address this issue, the presence of higher molecular
weight organic compounds in deep-sea hydrothermal fluids was assessed at
three sites along the Mid-Atlantic Ridge that span a range of
temperatures (51 to textgreater360 degrees C), fluid compositions, and host-rock
lithologies (mafic to ultramafic). Samples were obtained at several
sites within the Lucky Strike, Rainbow, and Lost City hydrothermal
fields. Three methods were employed to extract organic compounds for
analysis, including liquid: liquid extraction, cold trapping on the
walls of a coil of titanium tubing, and pumping fluids through
cartridges filled with solid phase extraction (SPE) sorbents. The only
samples to consistently yield high amounts of extractable organic
compounds were the warm (51-91 degrees C), highly alkaline fluids from
Lost City, which contained elevated concentrations of C-8, C-10, and
C-12 n-alkanoic acids and, in some cases, trithiolane, hexadecanol,
squalene, and cholesterol. Collectively, the C-8-C-12 acids can account
for about 15% of the total dissolved organic carbon in the Lost City
fluids. The even-carbon-number predominance of the alkanoic acids
indicates a biological origin, but it is unclear whether these compounds
are derived from microbial activity occurring within the hydrothermal
chimney proximal to the site of fluid discharge or are transported from
deeper within the system. Hydrothermal fluids from the Lucky Strike and
Rainbow fields were characterized by an overall scarcity of extractable
dissolved organic compounds. Trace amounts of aromatic hydrocarbons
including phenanthrenes and benzothiophene were the only compounds that
could be identified as indigenous components of these fluids. Although
hydrocarbons and fatty acids were observed in some samples, those
compounds were likely derived from particulate matter or biomass
entrained during fluid collection. In addition, extracts of some fluid
samples from the Rainbow field were found to contain an unresolved
complex mixture (UCM) of organic compounds. This UCM shared some
characteristics with organic matter extracted from bottom seawater,
suggesting that the organic matter observed in these samples might
represent seawater-derived compounds that had persisted, albeit with
partial alteration, during circulation through the hydrothermal system.
While there is considerable evidence that Rainbow and Lost City vent
fluids contain methane and other light hydrocarbons produced through
abiotic reduction of inorganic carbon, we found no evidence for more
complex organic compounds with an abiotic origin in the same fluids. (C)
2015 Elsevier Ltd. All rights reserved.
BibTeX:
@article{ISI:000352192100007,
  author = {McCollom, Thomas M and Seewald, Jeffrey S and German, Christopher R},
  title = {Investigation of extractable organic compounds in deep-sea hydrothermal vent fluids along the Mid-Atlantic Ridge},
  journal = {GEOCHIMICA ET COSMOCHIMICA ACTA},
  year = {2015},
  volume = {156},
  pages = {122--144},
  doi = {10.1016/j.gca.2015.02.022}
}
Perez-Rodriguez I, Bolognini M, Ricci J, Bini E and Vetriani C (2015), "From deep-sea volcanoes to human pathogens: a conserved quorum-sensing signal in Epsilonproteobacteria", ISME Journal., may, 2015. Vol. 9(5), pp. 1222-1234.
Abstract: Chemosynthetic Epsilonproteobacteria from deep-sea hydrothermal vents
colonize substrates exposed to steep thermal and redox gradients. In
many bacteria, substrate attachment, biofilm formation, expression of
virulence genes and host colonization are partly controlled via a cell
density-dependent mechanism involving signal molecules, known as quorum
sensing. Within the Epsilonproteobacteria, quorum sensing has been
investigated only in human pathogens that use the luxS/autoinducer-2
(AI-2) mechanism to control the expression of some of these functions.
In this study we showed that luxS is conserved in Epsilonproteobacteria
and that pathogenic and mesophilic members of this class inherited this
gene from a thermophilic ancestor. Furthermore, we provide evidence that
the luxS gene is expressed-and a quorum-sensing signal is
produced-during growth of Sulfurovum lithotrophicum and Caminibacter
mediatlanticus, two Epsilonproteobacteria from deep-sea hydrothermal
vents. Finally, we detected luxS transcripts in
Epsilonproteobacteria-dominated biofilm communities collected from
deep-sea hydrothermal vents. Taken together, our findings indicate that
the epsiloproteobacterial lineage of the LuxS enzyme originated in
high-temperature geothermal environments and that, in vent
Epsilonproteobacteria, luxS expression is linked to the production of
AI-2 signals, which are likely produced in situ at deep-sea vents. We
conclude that the luxS gene is part of the ancestral
epsilonproteobacterial genome and represents an evolutionary link that
connects thermophiles to human pathogens.
BibTeX:
@article{ISI:000353354100014,
  author = {Perez-Rodriguez, Ileana and Bolognini, Marie and Ricci, Jessica and Bini, Elisabetta and Vetriani, Costantino},
  title = {From deep-sea volcanoes to human pathogens: a conserved quorum-sensing signal in Epsilonproteobacteria},
  journal = {ISME Journal},
  year = {2015},
  volume = {9},
  number = {5},
  pages = {1222--1234},
  doi = {10.1038/ismej.2014.214}
}
Ajemian MJ, Wetz JJ, Shipley-Lozano B and Stunz GW (2015), "Rapid assessment of fish communities on submerged oil and gas platform reefs using remotely operated vehicles", FISHERIES RESEARCH., jul, 2015. Vol. 167, pp. 143-155.
Abstract: Remotely operated vehicles (ROVs) provide a non-extractive approach to
characterizing fish communities in complex habitats. Despite the
demonstrated effectiveness of ROVs in studying reef fishes over natural
hard-bottom and small artificial reefs, there has been little
application of this technology to larger artificial structures (10s of m
tall and wide), We explored the utility of ROVs in rapidly
characterizing an assemblage of fishes associated with an artificial
reef complex in the western Gulf of Mexico (26.9-28.2 degrees N;
95.5-97.0 degrees W) dominated by partially removed and toppled oil and
gas platforms. This study reports on an efficient method to sample these
structures, where we integrated depth-interval transect (DIT) and
continuous roving transect (CRT) protocols to document fish distribution
and community structure on 14 artificial reef sites. Consistent with
previous hydroacoustic studies, south Texas artificial reefs exhibited a
vertically heterogeneous distribution of fishes that varied with
structure orientation. These reefs were dominated by economically
important lutjanids and carangids, both of which presented sampling
challenges due to their patchy distribution around these vast
structures. The non-uniform distribution and mobility of these dominant
taxa highlight the utility of adopting roving approaches to assess fish
communities on these complex structures. We conclude our study with a
discussion of important logistical challenges associated with micro-ROV
surveys in deepwater habitats, and potential complementary approaches to
assist documentation of demersal fishes inhabiting a persistently turbid
bottom layer. (C) 2015 Elsevier B.V. All rights reserved.
BibTeX:
@article{ISI:000353740700016,
  author = {Ajemian, Matthew J and Wetz, Jennifer Jarrell and Shipley-Lozano, Brooke and Stunz, Gregory W},
  title = {Rapid assessment of fish communities on submerged oil and gas platform reefs using remotely operated vehicles},
  journal = {FISHERIES RESEARCH},
  year = {2015},
  volume = {167},
  pages = {143--155},
  doi = {10.1016/j.fishres.2015.02.011}
}
Streit K, Bennett SA, Van Dover CL and Coleman M (2015), "Sources of organic carbon for Rimicaris hybisae: Tracing individual fatty acids at two hydrothermal vent fields in the Mid-Cayman rise", DEEP-SEA RESEARCH PART I-OCEANOGRAPHIC RESEARCH PAPERS., jun, 2015. Vol. 100, pp. 13-20.
Abstract: Hydrothermal vents harbor ecosystems mostly decoupled from organic
carbon synthesized with the energy of sunlight (photosynthetic carbon
source) but fueled instead by oxidation of reduced compounds to generate
a chemosynthetic carbon source. Our study aimed to disentangle
photosynthetic and chemosynthetic organic carbon sources for the shrimp
species Rimicaris hybisae, a primary consumer presumed to obtain its
organic carbon mainly from ectosymbiotic chemoautotrophic bacteria
living on its gill cover membrane. To provide ectosymbionts with ideal
conditions for chemosynthesis, these shrimp live in dense clusters
around vent chimneys; they are, however, also found sparsely distributed
adjacent to diffuse vent flows, where they might depend on alternative
food sources. Densely and sparsely distributed shrimp were sampled and
dissected into abdominal tissue and gill cover membrane, covered with
ectosymbiotic bacteria, at two hydrothermal vent fields in the
Mid-Cayman rise that differ in vent chemistry. Fatty acids (FA) were
extracted from shrimp tissues and their carbon isotopic compositions
assessed. The FA data indicate that adult R. hybisae predominantly rely
on bacteria for their organic carbon needs. Their FA composition is
dominated by common bacterial FA of the n7 family (similar to 41%).
Bacterial FA of the n4 FA family are also abundant and found to
constitute good biomarkers for gill ectosymbionts. Sparsely distributed
shrimp contain fractions of n4 FA in gill cover membranes similar to 4%
lower than densely packed ones (similar to 18%) and much higher
fractions of photosynthetic FA in abdominal tissues, similar to 4% more
(compared with 1.6%), suggesting replacement of ectosymbionts along
with exoskeletons (molt), while they take up alternative diets of partly
photosynthetic organic carbon. Abdominal tissues also contain
photosynthetic FA from a second source taken up presumably during an
early dispersal phase and still present to c. 3% in adult shrimp. The
contribution of photosynthetic carbon to the FA pool of adult R. hybisae
is, however, overall small (max. 8%). Significant differences in carbon
isotopic values of chemosynthetically derived FA between vent fields
suggest that different dominant C fixation pathways are being used. (C)
2015 Published by Elsevier Ltd.
BibTeX:
@article{ISI:000354588900002,
  author = {Streit, Kathrin and Bennett, Sarah A and Van Dover, Cindy L and Coleman, Max},
  title = {Sources of organic carbon for Rimicaris hybisae: Tracing individual fatty acids at two hydrothermal vent fields in the Mid-Cayman rise},
  journal = {DEEP-SEA RESEARCH PART I-OCEANOGRAPHIC RESEARCH PAPERS},
  year = {2015},
  volume = {100},
  pages = {13--20},
  doi = {10.1016/j.dsr.2015.02.003}
}
McDermott JM, Seewald JS, German CR and Sylva SP (2015), "Pathways for abiotic organic synthesis at submarine hydrothermal fields", PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA., jun, 2015. Vol. 112(25), pp. 7668-7672.
Abstract: Arguments for an abiotic origin of low-molecular weight organic
compounds in deep-sea hot springs are compelling owing to implications
for the sustenance of deep biosphere microbial communities and their
potential role in the origin of life. Theory predicts that warm H-2-rich
fluids, like those emanating from serpentinizing hydrothermal systems,
create a favorable thermodynamic drive for the abiotic generation of
organic compounds from inorganic precursors. Here, we constrain two
distinct reaction pathways for abiotic organic synthesis in the natural
environment at the Von Damm hydrothermal field and delineate spatially
where inorganic carbon is converted into bioavailable reduced carbon. We
reveal that carbon transformation reactions in a single system can
progress over hours, days, and up to thousands of years. Previous
studies have suggested that CH4 and higher hydrocarbons in ultramafic
hydrothermal systems were dependent on H-2 generation during active
serpentinization. Rather, our results indicate that CH4 found in vent
fluids is formed in H-2-rich fluid inclusions, and higher n-alkanes may
likely be derived from the same source. This finding implies that, in
contrast with current paradigms, these compounds may form independently
of actively circulating serpentinizing fluids in ultramafic-influenced
systems. Conversely, widespread production of formate by SCO2 reduction
at Von Damm occurs rapidly during shallow subsurface mixing of the same
fluids, which may support anaerobic methanogenesis. Our finding of
abiogenic formate in deep-sea hot springs has significant implications
for microbial life strategies in the present- day deep biosphere as well
as early life on Earth and beyond.
BibTeX:
@article{ISI:000356731300054,
  author = {McDermott, Jill M and Seewald, Jeffrey S and German, Christopher R and Sylva, Sean P},
  title = {Pathways for abiotic organic synthesis at submarine hydrothermal fields},
  journal = {PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA},
  year = {2015},
  volume = {112},
  number = {25},
  pages = {7668--7672},
  doi = {10.1073/pnas.1506295112}
}
Grosche A, Sekaran H, Perez-Rodriguez I, Starovoytov V and Vetriani C (2015), "Cetia pacifica gen. nov., sp nov., a chemolithoautotrophic, thermophilic, nitrate-ammonifying bacterium from a deep-sea hydrothermal vent", INTERNATIONAL JOURNAL OF SYSTEMATIC AND EVOLUTIONARY MICROBIOLOGY., apr, 2015. Vol. 65(4), pp. 1144-1150.
Abstract: A thermophilic, anaerobic, chemolithoautotrophic bacterium, strain
TB-6(T), was isolated from a deep-sea hydrothermal vent located on the
East Pacific Rise at 9 degrees N. The cells were Gram-staining-negative
and rod-shaped with one or more polar flagella. Cell size was
approximately 1-1.5 mu m in length and 0.5 mu m in width. Strain TB-6(T)
grew between 45 and 70 degrees C (optimum 55-60 degrees C), 0 and 35 g
NaCl l(-1) (optimum 20-30 gl(-1)) and pH 4.5 and 7.5 (optimum pH
5.5-6.0). Generation time under optimal conditions was 2 h. Growth of
strain TB-6(T) occurred with H-2 as the energy source, CO2 as the carbon
source and nitrate or sulfur as electron acceptors, with formation of
ammonium or hydrogen sulfide, respectively. Acetate, (+)-n-glucose,
Casamino acids, sucrose and yeast extract were not used as carbon and
energy sources. Inhibition of growth occurred in the presence of
lactate, peptone and tryptone under a H-2/CO2 (80 :20; 200 kPa) gas
phase. Thiosulfate, sulfite, arsenate, selenate and oxygen were not used
as electron acceptors. The G +C content of the genomic DNA was 36.8
molo/o. Phylogenetic analysis of the 16S rRNA gene of strain TB-6(T)
showed that this organism branched separately from the three most
closely related genera, Caminibacter, Nautilia and Lebetimonas, within
the family Nautiliaceae. Strain TB-6(T) contained several unique fatty
acids in comparison with other members of the family Nautiliaceae. Based
on experimental evidence, it is proposed that the organism represents a
novel species and genus within the family Nautiliaceae, Cetia pacifica,
gen. nov., sp. nov. The type strain is TB-6(T) (=DSM 27783T=JCM
19563(T)).
BibTeX:
@article{ISI:000356841900006,
  author = {Grosche, Ashley and Sekaran, Hema and Perez-Rodriguez, Ileana and Starovoytov, Valentin and Vetriani, Costantino},
  title = {Cetia pacifica gen. nov., sp nov., a chemolithoautotrophic, thermophilic, nitrate-ammonifying bacterium from a deep-sea hydrothermal vent},
  journal = {INTERNATIONAL JOURNAL OF SYSTEMATIC AND EVOLUTIONARY MICROBIOLOGY},
  year = {2015},
  volume = {65},
  number = {4},
  pages = {1144--1150},
  doi = {10.1099/ijs.0.000070}
}
Troni G and Whitcomb LL (2015), "Advances in In Situ Alignment Calibration of Doppler and High/Low-end Attitude Sensors for Underwater Vehicle Navigation: Theory and Experimental Evaluation", JOURNAL OF FIELD ROBOTICS., aug, 2015. Vol. 32(5, SI), pp. 655-674.
Abstract: This paper reports the development and comparative performance
evaluation, using laboratory and at-sea field data, of new methods for
the problem of in situ calibration of the alignment rotation matrix
between Doppler sonar velocity sensors and attitude sensors arising in
the navigation of underwater vehicles. Most previously reported
solutions to this alignment calibration problem require the use of
absolute navigation fixes of the underwater vehicle, thus requiring
additional navigation sensors and/or beacons to be located externally
and apart from the underwater vehicle. We report four novel alignment
calibration methods employing only internal vehicle navigation sensors
for velocity, acceleration, attitude, and depth. We report the results
of comparative analysis of the performance of these new methods and a
previously reported method with a navigation laboratory and at-sea field
data. Laboratory data were obtained with the Johns Hopkins University
JHU remotely operated underwater vehicle in the JHU Hydrodynamic Test
Facility. At-sea field data were obtained from deep-water survey
missions of the Sentry autonomous underwater vehicle conducted in March,
2011 in the Kermadec Arc in the Southern Pacific Ocean. In addition, we
report a comparative experimental evaluation of several recently
reported calibration methods when employing low-cost
microelectromechanical system attitude sensors. In all these cases, the
results reveal consistent differences in performance of the various
methods when analyzed on navigation data from several different vehicle
dives.
BibTeX:
@article{ISI:000358016200003,
  author = {Troni, Giancarlo and Whitcomb, Louis L},
  title = {Advances in In Situ Alignment Calibration of Doppler and High/Low-end Attitude Sensors for Underwater Vehicle Navigation: Theory and Experimental Evaluation},
  journal = {JOURNAL OF FIELD ROBOTICS},
  year = {2015},
  volume = {32},
  number = {5, SI},
  pages = {655--674},
  doi = {10.1002/rob.21551}
}
Reed DC, Breier JA, Jiang H, Anantharaman K, Klausmeier CA, Toner BM, Hancock C, Speer K, Thurnherr AM and Dick GJ (2015), "Predicting the response of the deep-ocean microbiome to geochemical perturbations by hydrothermal vents", ISME JOURNAL., aug, 2015. Vol. 9(8), pp. 1857-1869.
Abstract: Submarine hydrothermal vents perturb the deep-ocean microbiome by
injecting reduced chemical species into the water column that act as an
energy source for chemosynthetic organisms. These systems thus provide
excellent natural laboratories for studying the response of microbial
communities to shifts in marine geochemistry. The present study explores
the processes that regulate coupled microbial-geochemical dynamics in
hydrothermal plumes by means of a novel mathematical model, which
combines thermodynamics, growth and reaction kinetics, and transport
processes derived from a fluid dynamics model. Simulations of a plume
located in the ABE vent field of the Lau basin were able to reproduce
metagenomic observations well and demonstrated that the magnitude of
primary production and rate of autotrophic growth are largely regulated
by the energetics of metabolisms and the availability of electron
donors, as opposed to kinetic parameters. Ambient seawater was the
dominant source of microbes to the plume and sulphur oxidisers
constituted almost 90% of the modelled community in the
neutrally-buoyant plume. Data from drifters deployed in the region
allowed the different time scales of metabolisms to be cast in a spatial
context, which demonstrated spatial succession in the microbial
community. While growth was shown to occur over distances of tens of
kilometers, microbes persisted over hundreds of kilometers. Given that
high-temperature hydrothermal systems are found less than 100 km apart
on average, plumes may act as important vectors between different vent
fields and other environments that are hospitable to similar organisms,
such as oil spills and oxygen minimum zones.
BibTeX:
@article{ISI:000358260100015,
  author = {Reed, Daniel C and Breier, John A and Jiang, Houshuo and Anantharaman, Karthik and Klausmeier, Christopher A and Toner, Brandy M and Hancock, Cathrine and Speer, Kevin and Thurnherr, Andreas M and Dick, Gregory J},
  title = {Predicting the response of the deep-ocean microbiome to geochemical perturbations by hydrothermal vents},
  journal = {ISME JOURNAL},
  year = {2015},
  volume = {9},
  number = {8},
  pages = {1857--1869},
  doi = {10.1038/ismej.2015.4}
}
Fu L, He Y, Xu F, Ma Q, Wang F and Xu J (2015), "Characterization of a novel thermostable patatin-like protein from a Guaymas basin metagenomic library", EXTREMOPHILES., jul, 2015. Vol. 19(4), pp. 829-840.
Abstract: Deep-sea hydrothermal vents are a natural habitat for thermophiles, in
which contain plenty of enzymes that can function at high temperatures.
In this work, we constructed a fosmid library in Escherichia coli using
metagenomic DNA isolated from a chimney sample collected in the
hydrothermal vents in Guaymas Basin. The library was screened for
lipolytic activity and positive clones were subjected to subcloning. A
novel patatin-like protein (PLP) that exhibited less than 45 % identity
in amino acid sequence to known enzymes was obtained. Common features of
the patatin-like proteins, such as four conserved blocks, were detected.
Interestingly, there was an Ala at site 42 in PLP instead of the first
Gly-residue in the consensus sequence Gly-X-Ser-X-Gly found in other PLP
homologs. The active sites of PLP were Ser44 and Asp160.
Spectrophotometric assays with different p-nitrophenyl esters
demonstrated a preference for p-nitrophenyl butyrate (C4) and
p-nitrophenyl decanoate (C10). Moreover, PLP demonstrated optimal
activity at 70 A degrees C and at pH 9.0 (Tris-HCl). The activation
energy from the linear Arrhenius plot was found to be 38.3 +/- A 0.9
kJ/mol. The K (m) and V (max) of PLP for C4 were 304 +/- A 38 mu M and
14 +/- A 0.38 mu mol min(-1) mg(-1), respectively. Gene-mining of the
metagenome dataset that was generated by pyrosequencing the same chimney
sample resulted in identification of 20 PLP homolog gene fragments,
which could represent promising examples of this category of
thermostable proteins.
BibTeX:
@article{ISI:000358290000012,
  author = {Fu, Ling and He, Ying and Xu, Fangdi and Ma, Qun and Wang, Fengping and Xu, Jun},
  title = {Characterization of a novel thermostable patatin-like protein from a Guaymas basin metagenomic library},
  journal = {EXTREMOPHILES},
  year = {2015},
  volume = {19},
  number = {4},
  pages = {829--840},
  doi = {10.1007/s00792-015-0758-x}
}
Forget NL, Perez M and Juniper SK (2015), "Molecular study of bacterial diversity within the trophosome of the vestimentiferan tubeworm Ridgeia piscesae", MARINE ECOLOGY-AN EVOLUTIONARY PERSPECTIVE., aug, 2015. Vol. 36(1, SI), pp. 35-44.
Abstract: A large proportion of the faunal biomass in hydrothermal vent ecosystems
relies on symbiotic relationships, with bacteria as a source of
nutrition. Whereas multiple symbioses have been observed in diverse vent
hosts, siboglinid tubeworms have been thought to harbour a single
endosymbiont phylotype affiliated to the Gammaproteobacteria. In the
case of the Northeast Pacific vestimentiferan Ridgeia piscesae, two
previous studies suggested the presence of more than one symbiont. The
possibility of multiple, and possibly habitat-specific, symbionts in R.
piscesae provided a potential explanation for the tube-worm's broad
ecological niche, compared with other hydrothermal vent siboglinids.
This study further explored the diversity of trophosome bacteria in R.
piscesae using two methodological approaches not yet applied to this
symbiosis. We carried out 454-pyrosequencing on trophosome samples from
46 individual worms and used catalyzed reporter deposition-fluorescence
in situ hybridization (CARD-FISH) to verify the presence of the major
groups detected in the pyrotag data. Both methods yielded inconsistent
and sometimes contradictory results between sampling sites, and neither
provided irrefutable evidence for the presence of symbionts other than
the expected Gammaproteobacteria. We therefore conclude that the other
adaptive mechanisms must be considered to explain the broad
physico-chemical niche occupied by the different growth forms of R.
piscesae.
BibTeX:
@article{ISI:000360368300003,
  author = {Forget, Nathalie L and Perez, Maeva and Juniper, S Kim},
  title = {Molecular study of bacterial diversity within the trophosome of the vestimentiferan tubeworm Ridgeia piscesae},
  journal = {MARINE ECOLOGY-AN EVOLUTIONARY PERSPECTIVE},
  year = {2015},
  volume = {36},
  number = {1, SI},
  pages = {35--44},
  doi = {10.1111/maec.12169}
}
Orcutt BN, Sylvan JB, Rogers DR, Delaney J, Lee RW and Girguis PR (2015), "Carbon fixation by basalt-hosted microbial communities", FRONTIERS IN MICROBIOLOGY., sep, 2015. Vol. 6
Abstract: Oceanic crust is a massive potential habitat for microbial life on Earth, yet our understanding of this ecosystem is limited due to difficulty in access. In particular, measurements of rates of microbial activity are sparse. We used stable carbon isotope incubations of crustal samples, coupled with functional gene analyses, to examine the potential for carbon fixation on oceanic crust. Both seafloor-exposed and subseafloor basalts were recovered from different mid-ocean ridge and hot spot environments (i.e., the Juan de Fuca Ridge, the Mid-Atlantic Ridge, and the Loihi Seamount) and incubated with C-13-labeled bicarbonate. Seafloor-exposed basalts revealed incorporation of C-13-label into organic matter over time, though the degree of incorporation was heterogeneous. The incorporation of C-13 into biomass was inconclusive in subseafloor basalts. Translating these measurements into potential rates of carbon fixation indicated that 0.1-10 nmol C g(-1) rock d(-1) could be fixed by seafloor-exposed rocks. When scaled to the global production of oceanic crust, this suggests carbon fixation rates of 10(9)-10(12) g C year(-1), which matches earlier predictions based on thermodynamic calculations. Functional gene analyses indicate that the Calvin cycle is likely the dominant biochemical mechanism for carbon fixation in basalt-hosted biofilms, although the reductive acetyl-CoA pathway and reverse TCA cycle likely play some role in net carbon fixation. These results provide empirical evidence for autotrophy in oceanic crust, suggesting that basalt-hosted autotrophy could be a significant contributor of organic matter in this remote and vast environment.
BibTeX:
@article{ISI:000360888000001,
  author = {Orcutt, Beth N and Sylvan, Jason B and Rogers, Daniel R and Delaney, Jennifer and Lee, Raymond W and Girguis, Peter R},
  title = {Carbon fixation by basalt-hosted microbial communities},
  journal = {FRONTIERS IN MICROBIOLOGY},
  year = {2015},
  volume = {6},
  doi = {10.3389/fmicb.2015.90400904}
}
Plum C, Gollner S, Martinez-Arbizu P and Bright M (2015), "Diversity and composition of the copepod communities associated with megafauna around a cold seep in the Gulf of Mexico with remarks on species biogeography", MARINE BIODIVERSITY., sep, 2015. Vol. 45(3), pp. 419-432.
Abstract: In order to characterize the copepod communities associated with tubeworm and mussel aggregations around a hydrocarbon seep in the Green Canyon of the Gulf of Mexico, diversity, abundance, and community composition were analyzed. Also analyzed were species biogeography and the potential connectivity to other chemosynthesis-based habitats. Copepod abundance and biomass were very low among tubeworms and mussels, with 0.22 to 6.08 individuals per 10 cm(2) sampled area and 9.02 to 42.43 mu g wet weight 10 cm(2) sampled area, respectively; but, abundance was significantly higher among the mussels. Fifty-five copepod species were identified, of which most were newly discovered and primarily belonging to the Harpacticoida order. Four copepod species were previously recorded from other food-rich and hard-substrata environments, such as hydrothermal vents or wood falls. Another four species showed close morphological proximity to species described from cold seeps, hydrothermal vents, and wood falls. Copepod diversity and community composition showed no significant differences between the foundation species. However, differences in the relative abundance and dominance of single species indicate a rather homogeneous community in mussel beds and a more heterogeneous community among tubeworms, indicating that foundation species may shape the abundance and community composition of associated copepods at cold seeps.
BibTeX:
@article{ISI:000361755600008,
  author = {Plum, Christoph and Gollner, Sabine and Martinez-Arbizu, Pedro and Bright, Monika},
  title = {Diversity and composition of the copepod communities associated with megafauna around a cold seep in the Gulf of Mexico with remarks on species biogeography},
  journal = {MARINE BIODIVERSITY},
  year = {2015},
  volume = {45},
  number = {3},
  pages = {419--432},
  doi = {10.1007/s12526-014-0310-8}
}
Mason OU, Case DH, Naehr TH, Lee RW, Thomas RB, Bailey JV and Orphan VJ (2015), "Comparison of Archaeal and Bacterial Diversity in Methane Seep Carbonate Nodules and Host Sediments, Eel River Basin and Hydrate Ridge, USA", MICROBIAL ECOLOGY., oct, 2015. Vol. 70(3), pp. 766-784.
Abstract: Anaerobic oxidation of methane (AOM) impacts carbon cycling by acting as
a methane sink and by sequestering inorganic carbon via AOM-induced
carbonate precipitation. These precipitates commonly take the form of
carbonate nodules that form within methane seep sediments. The timing
and sequence of nodule formation within methane seep sediments are not
well understood. Further, the microbial diversity associated with
sediment-hosted nodules has not been well characterized and the degree
to which nodules reflect the microbial assemblage in surrounding
sediments is unknown. Here, we conducted a comparative study of
microbial assemblages in methane-derived authigenic carbonate nodules
and their host sediments using molecular, mineralogical, and geochemical
methods. Analysis of 16S rRNA gene diversity from paired carbonate
nodules and sediments revealed that both sample types contained
methanotrophic archaea (ANME-1 and ANME-2) and syntrophic
sulfate-reducing bacteria (Desulfobacteraceae and Desulfobulbaceae), as
well as other microbial community members. The combination of
geochemical and molecular data from Eel River Basin and Hydrate Ridge
suggested that some nodules formed in situ and captured the local
sediment-hosted microbial community, while other nodules may have been
translocated or may represent a record of conditions prior to the
contemporary environment. Taken together, this comparative analysis
offers clues to the formation regimes and mechanisms of sediment-hosted
carbonate nodules.
BibTeX:
@article{ISI:000361984700015,
  author = {Mason, Olivia U and Case, David H and Naehr, Thomas H and Lee, Raymond W and Thomas, Randal B and Bailey, Jake V and Orphan, Victoria J},
  title = {Comparison of Archaeal and Bacterial Diversity in Methane Seep Carbonate Nodules and Host Sediments, Eel River Basin and Hydrate Ridge, USA},
  journal = {MICROBIAL ECOLOGY},
  year = {2015},
  volume = {70},
  number = {3},
  pages = {766--784},
  doi = {10.1007/s00248-015-0615-6}
}
Rona PA, Bemis KG, Xu G and Mitsuzawa K (2015), "Estimations of heat transfer from Grotto's North Tower: A NEPTUNE Observatory case study", DEEP-SEA RESEARCH PART II-TOPICAL STUDIES IN OCEANOGRAPHY., nov, 2015. Vol. 121(SI), pp. 95-111.
Abstract: The overall heat transfer through an active hydrothermal sulfide
edifice, in particular the North Tower of Grotto, has been estimated at
80 MW or greater based on the following in situ measurements and
assumptions: (1) The heat transfer by diffuse flow is estimated at
33-380 MW based on extrapolating the acoustically mapped area to all
sides of the North Tower (''visible'' area=30 m(2); extrapolated
area= 100 m(2)) and using the range of available spot measurements of
temperature (6-23 degrees C) and vertical velocity (0.07-0.28 m/s). The
lower number (33 MW) is more likely, but there is insufficient knowledge
of the temporal and spatial variability of diffuse flow to be certain.
(2) The heat transfer by focused flow is estimated at 30-70 MW based on
summing the estimated individual rates of heat transfer for 4 out of 7
documented black smokers and flanges. (3) Conductive heat transfer out
of the mound is unknown, but is likely to be much less than the
advective heat transfer. Additionally, the plume transport of heat is
estimated at 20-40 MW based on the direct measurement of temperature
within the plume (at 5-25 m above the top of the edifice). Despite
uncertainties, the lower estimate of plume versus smoker heat transfer
suggests that heat transfer is dominantly by diffuse flow. Furthermore,
not all plumes from individual smokers may merge even for so small an
area as the North Tower of Grotto. (C) 2015 Elsevier Ltd. All rights
reserved.
BibTeX:
@article{ISI:000365379500011,
  author = {Rona, Peter A and Bemis, Karen G and Xu, Guangyu and Mitsuzawa, Kyohiko},
  title = {Estimations of heat transfer from Grotto's North Tower: A NEPTUNE Observatory case study},
  journal = {DEEP-SEA RESEARCH PART II-TOPICAL STUDIES IN OCEANOGRAPHY},
  year = {2015},
  volume = {121},
  number = {SI},
  pages = {95--111},
  doi = {10.1016/j.dsr2.2015.05.010}
}
Gollner S, Govenar B, Arbizu PM, Mills S, Le Bris N, Weinbauer M, Shank TM and Bright M (2015), "Differences in recovery between deep-sea hydrothermal vent and vent-proximate communities after a volcanic eruption", DEEP-SEA RESEARCH PART I-OCEANOGRAPHIC RESEARCH PAPERS., dec, 2015. Vol. 106, pp. 167-182.
Abstract: Deep-sea hydrothermal vents and the surrounding basalt seafloor are
subject to major natural disturbance events such as volcanic eruptions.
In the near future, anthropogenic disturbance in the form of deep-sea
mining could also significantly affect the faunal communities of
hydrothermal vents. In this study, we monitor and compare the recovery
of insular, highly productive vent communities and vent-proximate basalt
communities following a volcanic eruption that destroyed almost all
existing communities at the East Pacific Rise, 9 degrees 50'N in 2006.
To study the recovery patterns of the benthic communities, we placed
settlement substrates at vent sites and their proximate basalt areas and
measured the prokaryotic abundance and compared the meio- and
macrofaunal species richness and composition at one, two and four years
after the eruption. In addition, we collected samples from the overlying
water column with a pelagic pump, at one and two years after the
volcanic eruption, to determine the abundance of potential meiofauna
colonisers. One year after eruption, mean meio- and macrofaunal
abundances were not significantly different from pre-eruption values in
vent habitats (meio: 8-1838 ind. 64 cm(-2) in 2006; 3-6246 ind. 64
cm(-2) in 2001/02; macro: 95-1600 ind. 64 cm(-2) in 2006; 205-4577 ind.
64 cm(-2) in 2001/02) and on non-vent basalt habitats (meio: 10-1922
ind. 64 cm(-2) in 2006; 8328 ind. 64 cm(-2) in 2003/04; macro: 14-3351
ind. 64 cm(-2) in 2006; 2-63 ind. 64 cm(-2) in 2003/04), but species
recovery patterns differed between the two habitat types. In the vent
habitat, the initial community recovery was relatively quick but
incomplete four years after eruption, which may be due to the good
dispersal capabilities of vent endemic macrofauna and vent endemic
dirivultid copepods. At vents, 42% of the pre-eruption meio- and 39%
of macrofaunal species had returned. In addition, some new species not
evident prior to the eruption were found. At the tubeworm site Tica, a
total of 26 meio- and 19 macrofaunal species were found in 2009, which
contrasts with the 24 meio- and 29 macrofauna species detected at the
site in 2001/01 In the basalt habitat, community recovery of meiofauna
was slower with only 28% of the original 64 species present four years
after eruption. The more limited dispersal capabilities of meiofauna
basalt specialists such as nematodes or harpacticoid copepods probably
caused this pattern. In contrast, 67% of the original 27 macrofaunal
species had recolonized the basalt by 2009. Our results suggest that not
only vent communities, but also species-rich communities of
vent-proximate habitats require attention in conservation efforts. (C)
2015 Elsevier Ltd. All rights reserved.
BibTeX:
@article{ISI:000366233300014,
  author = {Gollner, Sabine and Govenar, Breea and Arbizu, Pedro Martinez and Mills, Susan and Le Bris, Nadine and Weinbauer, Markus and Shank, Timothy M and Bright, Monika},
  title = {Differences in recovery between deep-sea hydrothermal vent and vent-proximate communities after a volcanic eruption},
  journal = {DEEP-SEA RESEARCH PART I-OCEANOGRAPHIC RESEARCH PAPERS},
  year = {2015},
  volume = {106},
  pages = {167--182},
  doi = {10.1016/j.dsr.2015.10.008}
}
Nedoncelle K, Lartaud F, Pereira LC, Yuecel M, Thurnherr AM, Mullineaux L and Le Bris N (2015), "Bathymodiolus growth dynamics in relation to environmental fluctuations in vent habitats", DEEP-SEA RESEARCH PART I-OCEANOGRAPHIC RESEARCH PAPERS., dec, 2015. Vol. 106, pp. 183-193.
Abstract: The deep-sea mussel Bathymodiolus thermophilus is a dominant species in
the East Pacific Rise (EPR) hydrothermal vent fields. On the EPR
volcanically unstable area, this late colonizer reaches high biomass
within 4-5 years on new habitats created. by lava flows. The
environmental conditions and growth rates characterizing the
reestablishment of B. thermophilus populations are however largely
unknown, leaving unconstrained the role of this foundation species in
the ecosystem dynamics. A typical example from the vent field at 9
degrees 50'N that was affected by the last massive eruption was the
Bio-9 hydrothermal vent site. Here, six years later, a large mussel
population had reestablished. The von Bertalanffy growth model estimates
the oldest B. thermophilus specimens to be 1.3 year-old in March 2012,
consistent with the observation of scarce juveniles among tubeworms in
2010. Younger cohorts were also observed in 2012 but the low number of
individuals, relatively to older cohorts, suggests limited survival or
growth of new recruits at this site, that could reflect unsuitable
habitat conditions. To further explore this asumption, we investigated
the relationships between mussel growth dynamics and habitat properties.
The approach combined sclerochronology analyses of daily shell growth
with continuous habitat monitoring for two mussel assemblages; one from
the Bio-9 new settlement and a second from the V-vent site unreached by
the lava flow. At both vent sites, semi-diurnal fluctuations of abiotic
conditions were recorded using sensors deployed in the mussel bed over 5
to 10 days. These data depict steep transitions from well oxygenated to
oxygen-depleted conditions and from alkaline to acidic pH, combined with
intermittent sulfide exposure. These semi-diurnal fluctuations exhibited
marked changes in amplitude over time, exposing mussels to distinct
regimes of abiotic constraints. The V-vent samples allowed growth
patterns to be examined at the scale of individual life and compared to
long-term records of habitat temperature and oceanographic mooring data
in the years following the eruption. Both shell growth and habitat
temperature at V-vent varied over the spring-neap tidal cycle and over
longer periods of c.a. 60 days. The correlation of growth rate with
temperature and, for some individuals, with current velocities supports
the idea that tidal forcing impacts growth. Its influence on habitat
conditions includes the spring-neap cycle, which is not reflected in
current velocities but influences the venting rate. Additionally, it is
expected that mesoscale eddies periodically passing across the ridge
imprint shell growth through the influence of bottom current on the
decimeter-thick mixing interface where mussels thrive. We conclude that
diurnal-semidiurnal tidal fluctuations exert major abiotic constraints
on B. thermophilus mussels and that low-frequency fluctuations act as
significant determinants on growth. Finally, we postulate that the
modulation of tidal fluctuations by large-scale hydrodynamic forcing
ultimately constrains the capacity of this mussel species to form high
biomass aggregations. This study indeed shows that the absence of these
strong hydrodynamic drivers would limit the alternance of oxic and
sulfidic conditions and significantly affect the growth rate of this
species over time. (C) 2015 Elsevier Ltd. All rights reserved.
BibTeX:
@article{ISI:000366233300015,
  author = {Nedoncelle, K and Lartaud, F and Pereira, L Contreira and Yuecel, M and Thurnherr, A M and Mullineaux, L and Le Bris, N},
  title = {Bathymodiolus growth dynamics in relation to environmental fluctuations in vent habitats},
  journal = {DEEP-SEA RESEARCH PART I-OCEANOGRAPHIC RESEARCH PAPERS},
  year = {2015},
  volume = {106},
  pages = {183--193},
  doi = {10.1016/j.dsr.2015.10.003}
}
Bernhard JM, Morrison CR, Pape E, Beaudoin DJ, Todaro MA, Pachiadaki MG, Kormas KA and Edgcomb VP (2015), "Metazoans of redoxcline sediments in Mediterranean deep-sea hypersaline anoxic basins", BMC BIOLOGY., dec, 2015. Vol. 13
Abstract: Background: The deep-sea hypersaline anoxic basins (DHABs) of the
Mediterranean (water depth similar to 3500 m) are some of the most
extreme oceanic habitats known. Brines of DHABs are nearly saturated
with salt, leading many to suspect they are uninhabitable for
eukaryotes. While diverse bacterial and protistan communities are
reported from some DHAB haloclines and brines, loriciferans are the only
metazoan reported to inhabit the anoxic DHAB brines. Our goal was to
further investigate metazoan communities in DHAB haloclines and brines.
Results: We report observations from sediments of three DHAB (Urania,
Discovery, L'Atalante) haloclines, comparing these to observations from
sediments underlying normoxic waters of typical Mediterranean salinity.
Due to technical difficulties, sampling of the brines was not possible.
Morphotype analysis indicates nematodes are the most abundant taxon;
crustaceans, loriciferans and bryozoans were also noted. Among
nematodes, Daptonema was the most abundant genus; three morphotypes were
noted with a degree of endemicity. The majority of rRNA sequences were
from planktonic taxa, suggesting that at least some individual metazoans
were preserved and inactive. Nematode abundance data, in some cases
determined from direct counts of sediments incubated in situ with
CellTracker (TM) Green, was patchy but generally indicates the highest
abundances in either normoxic control samples or in upper halocline
samples; nematodes were absent or very rare in lower halocline samples.
Ultrastructural analysis indicates the nematodes in L'Atalante normoxic
control sediments were fit, while specimens from L'Atalante upper
halocline were healthy or had only recently died and those from the
lower halocline had no identifiable organelles. Loriciferans, which were
only rarely encountered, were found in both normoxic control samples as
well as in Discovery and L'Atalante haloclines. It is not clear how a
metazoan taxon could remain viable under this wide range of conditions.
Conclusions: We document a community of living nematodes in normoxic,
normal saline deep-sea Mediterranean sediments and in the upper
halocline portions of the DHABs. Occurrences of nematodes in
mid-halocline and lower halocline samples did not provide compelling
evidence of a living community in those zones. The possibility of a
viable metazoan community in brines of DHABs is not supported by our
data at this time.
BibTeX:
@article{ISI:000366346800001,
  author = {Bernhard, Joan M and Morrison, Colin R and Pape, Ellen and Beaudoin, David J and Todaro, M Antonio and Pachiadaki, Maria G and Kormas, Konstantinos Ar and Edgcomb, Virginia P},
  title = {Metazoans of redoxcline sediments in Mediterranean deep-sea hypersaline anoxic basins},
  journal = {BMC BIOLOGY},
  year = {2015},
  volume = {13},
  doi = {10.1186/s12915-015-0213-6}
}
Grimes CB, Wooden JL, Cheadle MJ and John BE (2015), "``Fingerprinting'' tectono-magmatic provenance using trace elements in igneous zircon", CONTRIBUTIONS TO MINERALOGY AND PETROLOGY., dec, 2015. Vol. 170(5-6)
Abstract: Over 5300 recent SHRIMP-RG analyses of trace elements (TE) in igneous zircon have been compiled and classified based on their original tectono-magmatic setting to empirically evaluate ``geochemical fingerprints'' unique to those settings. Immobile element geochemical fingerprints used for lavas are applied with the same rational to zircon, including consideration of mineral competition on zircon TE ratios, and new criteria for distinguishing mid-ocean ridge (MOR), magmatic arc, and ocean island (and other plume-influenced) settings are proposed. The elemental ratios in zircon effective for fingerprinting tectono-magmatic provenance are systematically related to lava composition from equivalent settings. Existing discrimination diagrams using zircon U/Yb versus Hf or Y do not distinguish TE-enriched ocean island settings (i.e., Iceland, Hawaii) from magmatic arc settings. However, bivariate diagrams with combined cation ratios involving U-Nb-Sc-Yb-Gd-Ce provide a more complete distinction of zircon from these settings. On diagrams of U/Yb versus Nb/Yb, most MOR, ocean island, and kimberlite zircon define a broad ``mantle-zircon array''; arc zircon defines a parallel array offset to higher U/Yb. Distinctly low U/Yb ratios of MOR zircon (typically textless0.1) mirror their parental magmas and long-term incompatible element depletion of the MORB mantle. Plume-influenced sources are distinguished from MOR by higher U/Yb, U/Nb, Nb/Yb, and Nb/Sc. For zircon with U/Yb textgreater0.1, high Sc/Yb separates arc settings from low-Sc/Yb plume-influenced sources. The slope of scandium enrichment trends in zircon differ between MOR and continental arc settings, likely reflecting the involvement of amphibole during melt differentiation. Scandium is thus also critical for discriminating provenance, but its behavior in zircon probably reflects contrasting melt fractionation trends between tholeiitic and calc-alkaline systems more than compositional differences in primitive magmas sourced at each tectono-magmatic source.
BibTeX:
@article{ISI:000366805800006,
  author = {Grimes, C B and Wooden, J L and Cheadle, M J and John, B E},
  title = {``Fingerprinting'' tectono-magmatic provenance using trace elements in igneous zircon},
  journal = {CONTRIBUTIONS TO MINERALOGY AND PETROLOGY},
  year = {2015},
  volume = {170},
  number = {5-6},
  doi = {10.1007/s00410-015-1199-3}
}
Lee MD, Walworth NG, Sylvan JB, Edwards KJ and Orcutt BN (2015), "Microbial Communities on Seafloor Basalts at Dorado Outcrop Reflect Level of Alteration and Highlight Global Lithic Clades", FRONTIERS IN MICROBIOLOGY., dec, 2015. Vol. 6
Abstract: Areas of exposed basalt along mid-ocean ridges and at seafloor outcrops serve as conduits of fluid flux into and out of a subsurface ocean, and microbe-mineral interactions can influence alteration reactions at the rock-water interface. Located on the eastern flank of the East Pacific Rise, Dorado Outcrop is a site of low temperature (textless 20 degrees C) hydrothermal venting and represents a new end-member in the current survey of seafloor basalt biomes. Consistent with prior studies, a survey of 16S rRNA gene sequence diversity using universal primers targeting the V4 hypervariable region revealed much greater richness and diversity on the seafloor rocks than in surrounding seawater. Overall, Gamma-, Alpha-, and Deltaproteobacteria, and Thaumarchaeota dominated the sequenced communities, together making up over half of the observed diversity, though bacterial sequences were more abundant than archaeal in all samples. The most abundant bacterial reads were closely related to the obligate chemolithoautotrophic, sulfur-oxidizing Thioprofundum lifl-lotrophicum, suggesting carbon and sulfur cycling as dominant metabolic pathways in this system. Representatives of Thaumarchaeota were detected in relatively high abundance on the basalts in comparison to bottom water, possibly indicating ammonia oxidation. In comparison to other sequence datasets from globally distributed seafloor basalts, this study reveals many overlapping and cosmopolitan phylogenetic groups and also suggests that substrate age correlates with community structure.
BibTeX:
@article{ISI:000367001600001,
  author = {Lee, Michael D and Walworth, Nathan G and Sylvan, Jason B and Edwards, Katrina J and Orcutt, Beth N},
  title = {Microbial Communities on Seafloor Basalts at Dorado Outcrop Reflect Level of Alteration and Highlight Global Lithic Clades},
  journal = {FRONTIERS IN MICROBIOLOGY},
  year = {2015},
  volume = {6},
  doi = {10.3389/fmicb.2015.01470}
}
Kormas K, Pachiadaki M, Karayanni H, Leadbetter ER, Bernhard JM and Edgcomb VP (2015), "Inter-comparison of the potentially active prokaryotic communities in the halocline sediments of Mediterranean deep-sea hypersaline basins", Extremophiles. Vol. 19, pp. 949-960.
Abstract: The sediment microbiota of the Mediterranean deep-sea anoxic hypersaline basins (DHABs) are understudied relative to communities in the brines and halocline waters. In this study, the active fraction of the prokaryotic community in the halocline sediments of L' Atalante, Urania, and Discovery DHABs was investigated based on extracted total RNA and 454 pyrosequencing of the 16S rRNA gene. Bacterial and archaeal communities were different in the sediments underlying the halocline waters of the three habitats, reflecting the unique chemical settings of each basin. The relative abundance of unique operational taxonomic units (OTUs) was also different between deep-sea control sediments and sediments underlying DHAB haloclines, suggesting adaptation to the steep DHAB chemical gradients. Only a few OTUs were affiliated to known bacterial halophilic and/or anaerobic groups. Many OTUs, including some of the dominant ones, were related to aerobic taxa. Archaea were detected only in few halocline samples, with lower OTU richness relative to Bacteria, and were dominated by taxa associated with methane cycling. This study suggests that, while metabolically active prokaryotic communities appear to be present in sediments underlying the three DHABs investigated, their diversity and activity are likely to be more reduced in sediments underlying the brines.
BibTeX:
@article{Kormas2015,
  author = {Kormas, K and Pachiadaki, M and Karayanni, H and Leadbetter, E R and Bernhard, J M and Edgcomb, V P},
  title = {Inter-comparison of the potentially active prokaryotic communities in the halocline sediments of Mediterranean deep-sea hypersaline basins},
  journal = {Extremophiles},
  year = {2015},
  volume = {19},
  pages = {949--960}
}
Larson BI, Lang SQ, Lilley MD, Olson EJ, Lupton JE, Nakamura K and Buck NJ (2015), "Stealth export of hydrogen and methane from a low temperature serpentinization system", Deep-Sea Research Part II: Topical Studies in Oceanography. Vol. 121, pp. 233-245.
Abstract: Chemical input to the deep sea from hydrothermal systems is a globally distributed phenomenon. Hydrothermal discharge is one of the primary mechanisms by which the Earth's interior processes manifest themselves at the Earth's surface, and it provides a source of energy for autotrophic processes by microbes that are too deep to capitalize on sunlight. Much is known about the water-column signature of this discharge from high-temperature mid-ocean Ridge (MOR) environments and their neighboring low-temperature counterparts. Hydrothermal discharge farther away from the ridge, however, has garnered less attention, owing in part to the difficulty in finding this style of venting, which eludes methods of detection that work well for high-temperature ‘black smoker'-type venting. Here we present a case study of the plume from one such ‘invisible' off-axis environment, The Lost City, with an emphasis on the dissolved volatile content of the hydrothermal plume. Serpentinization and abiotic organic synthesis generate significant concentrations of H2 and CH4 in vent fluid, but these species are unevenly transported to the overlying plume, which itself appears to be a composite of two different sources. A concentrated vent cluster on the talus slope channels fluid through at least eight chimneys, producing a water-column plume with the highest observed concentrations of CH4 in the field. In contrast, a saddle in the topography leading up to a carbonate cap hosts broadly distributed, nearly invisible venting apparent only in its water-column signals of redox potential and dissolved gas content, including the highest observed plume H2. After normalizing H2 and CH4 to the 3He background-corrected anomaly (3HeΔ) to account for mixing and relative amount of mantle input, it appears that, while a minimum of 60% of CH4 is transported out of the system, greater than 90% of the H2 is consumed in the subsurface prior to venting. The exception to this pattern occurs in the plume originating from the area dubbed Chaff Beach, in which somewhat more than 10% of the original H2 remains, indicating that this otherwise unremarkable plume, and others like it, may represent a significant source of H2 to the deep sea.
BibTeX:
@article{Larson2015,
  author = {Larson, B I and Lang, S Q and Lilley, M D and Olson, E J and Lupton, J E and Nakamura, K and Buck, N J},
  title = {Stealth export of hydrogen and methane from a low temperature serpentinization system},
  journal = {Deep-Sea Research Part II: Topical Studies in Oceanography},
  year = {2015},
  volume = {121},
  pages = {233--245},
  doi = {10.1016/j.dsr2.2015.05.007}
}
Lee RW, Robert K, Matabos M, Bates AE and Juniper SK (2015), "Temporal and spatial variation in temperature experienced by macrofauna at Main Endeavour hydrothermal vent field", Deep-Sea Research Part I: Oceanographic Research Papers. Vol. 106, pp. 154-166.
Abstract: A significant focus of hydrothermal vent ecological studies has been to understand how species cope with various stressors through physiological tolerance and biochemical resistance. Yet, the environmental conditions experienced by vent species have not been well characterized. This objective requires continuous observations over time intervals that can capture environmental variability at scales that are relevant to animals. We used autonomous temperature logger arrays (four roughly parallel linear arrays of 12 loggers spaced every 10–12 cm) to study spatial and temporal variations in the thermal regime experienced by hydrothermal vent macrofauna at a diffuse flow vent. Hourly temperatures were recorded over eight months from 2010 to 2011 at Grotto vent in the Main Endeavour vent field on the Juan de Fuca Ridge, a focus area of the Ocean Networks Canada cabled observatory. The conspicuous animal assemblages in video footage contained Ridgeia piscesae tubeworms, gastropods (primarily Lepetodrilus fucensis), and polychaetes (polynoid scaleworms and the palm worm Paralvinella palmiformis). Two dimensional spatial gradients in temperature were generally stable over the deployment period. The average temperature recorded by all arrays, and in some individual loggers, revealed distinctive fluctuations in temperature that often corresponded with the tidal cycle. We postulate that this may be related to changes in bottom currents or fluctuations in vent discharge. A marked transient temperature increase lasting over a period of days was observed in April 2011. While the distributions and behavior of Juan de Fuca Ridge vent invertebrates may be partially constrained by environmental temperature and temperature tolerance, except for the one transient high-temperature event, observed fluid temperatures were generally similar to the thermal preferences for some species, and typically well below lethal temperatures for all species. Average temperatures of the four arrays ranged from 4.1 to 11.0 °C during the deployment, indicating that on an hourly timescale the temperature conditions in this tubeworm community were fairly moderate and stable. The generality of these findings and behavioral responses of vent organisms to predictable
BibTeX:
@article{Lee2015,
  author = {Lee, R W and Robert, K and Matabos, M and Bates, A E and Juniper, S K},
  title = {Temporal and spatial variation in temperature experienced by macrofauna at Main Endeavour hydrothermal vent field},
  journal = {Deep-Sea Research Part I: Oceanographic Research Papers},
  year = {2015},
  volume = {106},
  pages = {154--166},
  doi = {10.1016/j.dsr.2015.10.004}
}
Li M, Baker BJ, Anantharaman K, Jain S, Breier JA and Dick GJ (2015), "Genomic and transcriptomic evidence for scavenging of diverse organic compounds by widespread deep-sea archaea", Nature Communications. Vol. 6, pp. 8933.
Abstract: Microbial activity is one of the most important processes to mediate the flux of organic carbon from the ocean surface to the seafloor. However, little is known about the microorganisms that underpin this key step of the global carbon cycle in the deep oceans. Here we present genomic and transcriptomic evidence that five ubiquitous archaeal groups actively use proteins, carbohydrates, fatty acids and lipids as sources of carbon and energy at depths ranging from 800 to 4,950 m in hydrothermal vent plumes and pelagic background seawater across three different ocean basins. Genome-enabled metabolic reconstructions and gene expression patterns show that these marine archaea are motile heterotrophs with extensive mechanisms for scavenging organic matter. Our results shed light on the ecological and physiological properties of ubiquitous marine archaea and highlight their versatile metabolic strategies in deep oceans that might play a critical role in global carbon cycling.
BibTeX:
@article{Li2015,
  author = {Li, M and Baker, B J and Anantharaman, K and Jain, S and Breier, J A and Dick, G J},
  title = {Genomic and transcriptomic evidence for scavenging of diverse organic compounds by widespread deep-sea archaea},
  journal = {Nature Communications},
  year = {2015},
  volume = {6},
  pages = {8933},
  doi = {10.1038/ncomms9933}
}
Lin H-T, Amend JP, LaRowe DE, Bingham J-P and Cowen JP (2015), "Dissolved amino acids in oceanic basaltic basement fluids", Geochimica et Cosmochimica Acta. Vol. 164, pp. 175-190.
Abstract: The oceanic basaltic basement contains the largest aquifer on Earth and potentially plays an important role in the global carbon cycle as a net sink for dissolved organic carbon (DOC). However, few details of the organic matter cycling in the subsurface are known because great water depths and thick sediments typically hinder direct access to this environment. In an effort to examine the role of water–rock–microorganism interaction on organic matter cycling in the oceanic basaltic crust, basement fluid samples collected from three borehole observatories installed on the eastern flank of the Juan de Fuca Ridge were analyzed for dissolved amino acids. Our data show that dissolved free amino acids (1–13 nM) and dissolved hydrolyzable amino acids (43–89 nM) are present in the basement. The amino acid concentrations in the ridge-flank basement fluids are at the low end of all submarine hydrothermal fluids reported in the literature and are similar to those in deep seawater. Amino acids in recharging deep seawater, in situ amino acid production, and diffusional input from overlying sediments are potential sources of amino acids in the basement fluids. Thermodynamic modeling shows that amino acid synthesis in the basement can be sustained by energy supplied from inorganic substrates via chemolithotrophic metabolisms. Furthermore, an analysis of amino acid concentrations and compositions in basement fluids support the notion that heterotrophic activity is ongoing. Similarly, the enrichment of acidic amino acids and depletion of hydrophobic ones relative to sedimentary particulate organic matter suggests that surface sorption and desorption also alters amino acids in the basaltic basement. In summary, although the oceanic basement aquifer is a net sink for deep seawater DOC, similar amino acid concentrations in basement aquifer and deep seawater suggest that DOC is preferentially removed in the basement over dissolved amino acids. Our data also suggest that organic carbon cycling occurs in the oceanic basaltic basement, where an active subsurface biosphere is likely responsible for amino acid synthesis and degradation.
BibTeX:
@article{Lin2015,
  author = {Lin, H-T and Amend, J P and LaRowe, D E and Bingham, J-P and Cowen, J P},
  title = {Dissolved amino acids in oceanic basaltic basement fluids},
  journal = {Geochimica et Cosmochimica Acta},
  year = {2015},
  volume = {164},
  pages = {175--190},
  doi = {10.1016/j.gca.2015.04.044}
}
Mavor JW (2015), "Observation windows of the deep submersible Alvin", Marine Technology Society Journal. Vol. 49(6), pp. 17-31.
Abstract: The basis of the design of ALVIN plexiglas windows is presented. Results of several tests of plexiglas windows are presented and discussed. It is concluded that the lapping of windows into their seats is unnecessary and that a close fit is not required. ALVIN windows are conservative in design for the operating depth of 6000 feet. The use of a test window seat which does not simulate the hull strains is satisfactory for window test. It is recommended that the conical window seat be extended inward beyond the window to allow for normal elastic extrusion. Plexiglas windows are susceptible to collision damage due to brittleness and low strength of the material. An external rubber gasket is required to prevent low pressure leakage.
BibTeX:
@article{Mavor2015,
  author = {Mavor, J W},
  title = {Observation windows of the deep submersible Alvin},
  journal = {Marine Technology Society Journal},
  year = {2015},
  volume = {49},
  number = {6},
  pages = {17--31}
}
McDermott JM, Ono S, Tivey MK, Seewald JS and Shanks WC (2015), "Identification of sulfur sources and isotopic equilibria in submarine hot-springs using multiple sulfur isotopes", Geochimica et Cosmochimica Acta. Vol. 160, pp. 169-187.
Abstract: Multiple sulfur isotopes were measured in metal sulfide deposits, elemental sulfur, and aqueous hydrogen sulfide to constrain sulfur sources and the isotopic systematics of precipitation in seafloor hydrothermal vents. Areas studied include the Eastern Manus Basin and Lau Basin back-arc spreading centers and the unsedimented basalt-hosted Southern East Pacific Rise (SEPR) and sediment-hosted Guaymas Basin mid-ocean ridge spreading centers. Chalcopyrite and dissolved hydrogen sulfide (H2S) δ34S values range from −5.5‰ to +5.6‰ in Manus Basin samples, +2.4‰ to +6.1‰ in Lau Basin samples, and +3.7‰ to +5.7‰ in SEPR samples. Values of δ34S for cubic cubanite and H2S range from −1.4‰ to +4.7‰ in Guaymas Basin samples. Multiple sulfur isotope systematics in fluid-mineral pairs from the SEPR and Lau Basin show that crustal host rock and thermochemical reduction of seawater-derived dissolved sulfate (SO4) are the primary sources of sulfur in mid-ocean ridge and some back-arc systems. At PACMANUS and SuSu Knolls hydrothermal systems in the Eastern Manus Basin, a significant contribution of sulfur is derived from disproportionation of magmatic sulfur dioxide (SO2), while the remaining sulfur is derived from crustal host rocks and SO4 reduction. At the sedimented Guaymas Basin hydrothermal system, sulfur sources include crustal host rock, reduced seawater SO4, and biogenic sulfide. Vent fluid flow through fresher, less-mature sediment supplies an increased quantity of reactant organic compounds that may reduce 34S-enriched SO4, while fluid interaction with more highly-altered sediments results in H2S characterized by a small, but isotopically-significant input of 34S-depleted biogenic sulfides. Near-zero Δ33S values in all samples implicate the abiotic processes of SO4 reduction and leaching of host rock as the major contributors to sulfur content at a high temperature unsedimented mid-ocean ridge and at a back-arc system. Δ33S values indicate that SO2 disproportionation is an additional process that contributes sulfur to a different back-arc system and to acid spring-type hydrothermal fluid circulation. At the sedimented Guaymus Basin, near-zero Δ33S values are also observed, despite negative δ34S values that indicate inputs of biogenic pyrite for some samples. In contrast with previous studies reporting isotope disequilibrium between H2S and chalcopyrite, the δ34S values of chalcopyrite sampled from the inner 1–2 mm of a chimney wall are within ±1‰ of δ34S values for H2S in the paired vent fluid, suggesting equilibrium fluid-mineral sulfur isotope exchange at 300–400 °C. Isotopic equilibrium between hydrothermal fluid H2S and precipitating chalcopyrite implies that sulfur isotopes in the chalcopyrite lining across a chimney wall may accurately record past hydrothermal activity.
BibTeX:
@article{McDermott2015,
  author = {McDermott, J M and Ono, S and Tivey, M K and Seewald, J S and Shanks, W C},
  title = {Identification of sulfur sources and isotopic equilibria in submarine hot-springs using multiple sulfur isotopes},
  journal = {Geochimica et Cosmochimica Acta},
  year = {2015},
  volume = {160},
  pages = {169--187},
  doi = {10.1016/j.gca.2015.02.016}
}
O'Brien CE, Giovannelli D, Govenar BW, Luther GW, Lutz RA, Shank TM and Vetriani C (2015), "Microbial biofilms associated with fluid chemistry and megafaunal colonization at post-eruptive deep-sea hydrothermal vents", Deep-Sea Research Part II: Topical Studies in Oceanography. Vol. 121, pp. 31-40.
Abstract: At deep-sea hydrothermal vents, reduced, super-heated hydrothermal fluids mix with cold, oxygenated seawater. This creates temperature and chemical gradients that support chemosynthetic primary production and a biomass-rich community of invertebrates. In late 2005/early 2006 an eruption occurred on the East Pacific Rise at 9°50′N, 104°17′W. Direct observations of the post-eruptive diffuse-flow vents indicated that the earliest colonizers were microbial biofilms. Two cruises in 2006 and 2007 allowed us to monitor and sample the early steps of ecosystem recovery. The main objective of this work was to characterize the composition of microbial biofilms in relation to the temperature and chemistry of the hydrothermal fluids and the observed patterns of megafaunal colonization. The area selected for this study had local seafloor habitats of active diffuse flow (in-flow) interrupted by adjacent habitats with no apparent expulsion of hydrothermal fluids (no-flow). The in-flow habitats were characterized by higher temperatures (1.6–25.2 °C) and H2S concentrations (up to 67.3 µM) than the no-flow habitats, and the microbial biofilms were dominated by chemosynthetic Epsilonproteobacteria. The no-flow habitats had much lower temperatures (1.2–5.2 °C) and H2S concentrations (0.3–2.9 µM), and Gammaproteobacteria dominated the biofilms. Siboglinid tubeworms colonized only in-flow habitats, while they were absent at the no-flow areas, suggesting a correlation between siboglinid tubeworm colonization, active hydrothermal flow, and the composition of chemosynthetic microbial biofilms.
BibTeX:
@article{OBrien2015,
  author = {O'Brien, C E and Giovannelli, D and Govenar, B W and Luther, G W and Lutz, R A and Shank, T M and Vetriani, C},
  title = {Microbial biofilms associated with fluid chemistry and megafaunal colonization at post-eruptive deep-sea hydrothermal vents},
  journal = {Deep-Sea Research Part II: Topical Studies in Oceanography},
  year = {2015},
  volume = {121},
  pages = {31--40},
  doi = {10.1016/j.dsr2.2015.07.020}
}
Quattrini AM, Baums IB, Shank TM, Morrison C and Cordes EE (2015), "Testing the depth-differentiation hypothesis in a deepwater octocoral", Proceedings of the Royal Society B: Biological Sciences. Vol. 282(1807), pp. 20150008.
Abstract: The depth-differentiation hypothesis proposes that the bathyal region is a source of genetic diversity and an area where there is a high rate of species formation. Genetic differentiation should thus occur over relatively small vertical distances, particularly along the upper continental slope (200-1000 m) where oceanography varies greatly over small differences in depth. To test whether genetic differentiation within deepwater octocorals is greater over vertical rather than geographical distances, Callogorgia delta was targeted. This species commonly occurs throughout the northern Gulf of Mexico at depths ranging from 400 to 900 m. We found significant genetic differentiation (FST = 0.042) across seven sites spanning 400 km of distance and 400 m of depth. A pattern of isolation by depth emerged, but geographical distance between sites may further limit gene flow. Water mass boundaries may serve to isolate populations across depth; however, adaptive divergence with depth is also a possible scenario. Microsatellite markers also revealed significant genetic differentiation (FST = 0.434) between C. delta and a closely related species, Callogorgia americana, demonstrating the utility of microsatellites in species delimitation of octocorals. Results provided support for the depth-differentiation hypothesis, strengthening the notion that factors covarying with depth serve as isolation mechanisms in deep-sea populations.
BibTeX:
@article{Quattrini2015,
  author = {Quattrini, A M and Baums, I B and Shank, T M and Morrison, C and Cordes, E E},
  title = {Testing the depth-differentiation hypothesis in a deepwater octocoral},
  journal = {Proceedings of the Royal Society B: Biological Sciences},
  year = {2015},
  volume = {282},
  number = {1807},
  pages = {20150008},
  doi = {10.1098/rspb.2015.0008}
}
Scott JJ, Breier JA, Luther GW and Emerson D (2015), "Microbial Iron Mats at the Mid-Atlantic Ridge and Evidence that Zetaproteobacteria May Be Restricted to Iron-Oxidizing Marine Systems", PLoS ONE. Vol. 10(3), pp. e0119284.
Abstract: Chemolithoautotrophic iron-oxidizing bacteria play an essential role in the global iron cycle. Thus far, the majority of marine iron-oxidizing bacteria have been identified as Zetaproteobacteria, a novel class within the phylum Proteobacteria. Marine iron-oxidizing microbial communities have been found associated with volcanically active seamounts, crustal spreading centers, and coastal waters. However, little is known about the presence and diversity of iron-oxidizing communities at hydrothermal systems along the slow crustal spreading center of the Mid-Atlantic Ridge. From October to November 2012, samples were collected from rust-colored mats at three well-known hydrothermal vent systems on the Mid-Atlantic Ridge (Rainbow, Trans-Atlantic Geotraverse, and Snake Pit) using the ROV Jason II. The goal of these efforts was to determine if iron-oxidizing Zetaproteobacteria were present at sites proximal to black smoker vent fields. Small, diffuse flow venting areas with high iron(II) concentrations and rust-colored microbial mats were observed at all three sites proximal to black smoker chimneys. A novel, syringe-based precision sampler was used to collect discrete microbial iron mat samples at the three sites. The presence of Zetaproteobacteria was confirmed using a combination of 16S rRNA pyrosequencing and single-cell sorting, while light micros-copy revealed a variety of iron-oxyhydroxide structures, indicating that active iron-oxidizing communities exist along the Mid-Atlantic Ridge. Sequencing analysis suggests that these iron mats contain cosmopolitan representatives of Zetaproteobacteria, but also exhibit diversity that may be uncommon at other iron-rich marine sites studied to date. A meta-analysis of publically available data encompassing a variety of aquatic habitats indicates that Zetaproteobacteria are rare if an iron source is not readily available. This work adds to the growing understanding of Zetaproteobacteria ecology and suggests that this organism is likely locally restricted to iron-rich marine environments but may exhibit wide-scale geographic distribution, further underscoring the importance of Zetaproteobacteria in global iron cycling.
BibTeX:
@article{Scott2015,
  author = {Scott, J J and Breier, J A and Luther, G W and Emerson, D},
  title = {Microbial Iron Mats at the Mid-Atlantic Ridge and Evidence that Zetaproteobacteria May Be Restricted to Iron-Oxidizing Marine Systems},
  journal = {PLoS ONE},
  year = {2015},
  volume = {10},
  number = {3},
  pages = {e0119284},
  doi = {10.1371/journal.pone.0119284}
}
Seyfried WE, Pester NJ, Tutolo BM and Ding K (2015), "The Lost City hydrothermal system: Constraints imposed by vent fluid chemistry and reaction path models on subseafloor heat and mass transfer processes", Geochimica et Cosmochimica Acta. Vol. 163, pp. 59-79.
Abstract: Since the first reported discovery of the Lost City hydrothermal system in 2001, it was recognized that seawater alteration of ultramafic rocks plays a key role in the composition of the coexisting vent fluids. The unusually high pH and high concentrations of H2 and CH4 provide compelling evidence for this. Here we report the chemistry of hydrothermal fluids sampled from two vent structures (Beehive: ∼90–116 °C, and M6: ∼75 °C) at Lost City in 2008 during cruise KNOX18RR using ROV Jason 2 and R/V Revelle assets. The vent fluid chemistry at both sites reveals considerable overlap in concentrations of dissolved gases (H2, CH4), trace elements (Cs, Rb, Li, B and Sr), and major elements (SO4, Ca, K, Na, Cl), including a surprising decrease in dissolved Cl, suggesting a common source fluid is feeding both sites. The absence of Mg and relatively high concentrations of Ca and sulfate suggest solubility control by serpentine–diopside–anhydrite, while trace alkali concentrations, especially Rb and Cs, are high, assuming a depleted mantle protolith. In both cases, but especially for Beehive vent fluid, the silica concentrations are well in excess of those expected for peridotite alteration and the coexistence of serpentine–brucite at all reasonable temperatures. However, both the measured pH and silica values are in better agreement with serpentine–diopside–tremolite-equilibria. Geochemical modeling demonstrates that reaction of plagioclase with serpentinized peridotite can shift the chemical system away from brucite and into the tremolite stability field. This is consistent with the complex intermingling of peridotite and gabbroic bodies commonly observed within the Atlantis Massif. We speculate the existence of such plagioclase bearing peridotite may also account for the highly enriched trace alkali (Cs, Rb) concentrations in the Lost City vent fluids. Additionally, reactive transport modeling taking explicit account of temperature dependent rates of mineral dissolution and precipitation clarifies the feedback between permeability, heat loss, and changes in the dissolved Si of the vent fluids. Assuming both the Beehive and M6 vent fluids were sourced at similar subseafloor conditions (tremolite buffered at 200 °C), model results indicate loss of approximately 30% Si upon cooling to ∼150 °C during upflow. However, Si concentrations remained largely conservative with continued cooling to lower temperatures owing to unfavorable reaction kinetics. While consistent with the Beehive endmember composition, these results fail to explain the relative Si depletion in the lower temperature M6 fluids. Thus, it may be that more robust kinetic models for silicates are needed to accurately account for the mechanism and rate of silica removal in the unusually high pH of the Lost City vent fluids.
BibTeX:
@article{Seyfried2015,
  author = {Seyfried, W E and Pester, N J and Tutolo, B M and Ding, K},
  title = {The Lost City hydrothermal system: Constraints imposed by vent fluid chemistry and reaction path models on subseafloor heat and mass transfer processes},
  journal = {Geochimica et Cosmochimica Acta},
  year = {2015},
  volume = {163},
  pages = {59--79},
  doi = {10.1016/j.gca.2015.04.040}
}
Zhang H, Johnson SB, Flores VR and Vrijenhoek RC (2015), "Intergradation between discrete lineages of Tevnia jerichonana, a deep-sea hydrothermal vent tubeworm", Deep-Sea Research Part II: Topical Studies in Oceanography. Vol. 121, pp. 53-61.
Abstract: We describe a broad zone of intergradation between genetically differentiated, northern and southern lineages of the hydrothermal vent tubeworm, Tevnia jerichonana. DNA sequences from four genes, nuclear HSP and ATPsα and mitochondrial COI and Cytb were examined in samples from eastern Pacific vent localities between 13°N and 38°S latitude. Allelic frequencies at these loci exhibited concordant latitudinal clines, and genetic differentiation (pairwise ΦST's) increased with geographical distances between sample localities. Though this pattern of differentiation suggested isolation-by-distance (IBD), it appeared to result from hierarchical population structure. Genotypic assignment tests identified two population clusters comprised of samples from the northern East Pacific Rise (NEPR: 9–13°N) and an extension of the Pacific-Antarctic Ridge (PAR: 31–32°S) with a zone of intergradation along the southern East Pacific Rise (SEPR: 7–17°S). The overall degrees of DNA sequence divergence between the NEPR and PAR populations were slight and not indicative of lengthy isolation. Bayesian assignment methods suggested that the SEPR populations constitute intergrades that connect the NEPR and PAR populations. Though it typically is difficult to distinguish between primary and secondary intergradation, our results were consistent with parallel studies of vent-restricted species that suggest a high degree of demographic instability along the superfast-spreading SEPR axis. Frequent local extinctions and immigration from NEPR and PAR refugia probably shaped the observed pattern of intergradation.
BibTeX:
@article{Zhang2015,
  author = {Zhang, H and Johnson, S B and Flores, V R and Vrijenhoek, R C},
  title = {Intergradation between discrete lineages of Tevnia jerichonana, a deep-sea hydrothermal vent tubeworm},
  journal = {Deep-Sea Research Part II: Topical Studies in Oceanography},
  year = {2015},
  volume = {121},
  pages = {53--61},
  doi = {10.1016/j.dsr2.2015.04.028}
}
(2015), "Centuries-old shipwreck discovered off North Carolina", Ocean News & Technology. Vol. 21(7), pp. 16.
Abstract: Scanning sonar from a scientific expedition has revealed the remains of a previously unknown shipwreck more than a mile deep off the North Carolina coast. Artifacts on the wreck indicate it might date to the American Revolution. Marine scientists from Duke University, North Carolina State University and the University of Oregon discovered the wreck on 12 July during a research expedition aboard the Woods Hole Oceanographic Institution (WHOI) research ship Atlantis. They spotted the wreck while using WHOI's AUV Sentry and the manned submersible Alvin. The team had been searching for a mooring that was deployed on a previous research trip in the area in 2012.
BibTeX:
@article{,,
  title = {Centuries-old shipwreck discovered off North Carolina},
  journal = {Ocean News & Technology},
  year = {2015},
  volume = {21},
  number = {7},
  pages = {16}
}
Baumberger T, Lilley MD, Resing JA, Lupton JE, Baker ET, Butterfield DA, Olson EJ and Fruh-Green GL (2014), "Understanding a submarine eruption through time series hydrothermal plume sampling of dissolved and particulate constituents: West Mata, 2008-2012", Geochemistry, Geophysics, Geosystems. Vol. 15(12), pp. 4631-4650.
Abstract: Four cruises between 2008 and 2012 monitored the continuing eruption of West Mata volcano in the NE Lau Basin as it produced plumes of chemically altered water above its summit. Although large enrichments in He-3, CO2, Fe, and Mn were observed in the plumes, the most notable enrichment was that of H-2, which reached concentrations as high as 14,843 nM. Strongly enriched H-2 concentrations in the water column result from reactions between seawater or magmatic water and extremely hot rocks. In 2008, the observation of elevated H-2 concentrations in the water column above West Mata pointed to vigorous ongoing eruptions at the volcano's summit. The eruption was confirmed by visual observations made by the ROV Jason 2 in 2009 and demonstrated that H-2 measurements are a vital instrument to detect ongoing volcanic eruptions at the seafloor. Elevated H-2 in 2010 showed that the eruption was ongoing, although at a reduced level given a maximum H-2 concentration of 4410 nM. In 2012, H-2 levels in the water column declined significantly, to a maximum of only 7 nM, consistent with visual observations from the Quest-4000 ROV that found no evidence of an ongoing volcanic eruption. Methane behaved independently of other measured gases and its concentrations in the hydrothermal plume were very low. We attribute its minimal enrichments to a mixture of mantle carbon reduced to CH4 and biological CH4 from diffuse flow sites. This study demonstrates that ongoing submarine volcanic eruptions are characterized by high dissolved H-2 concentrations present in the overlying water column.
BibTeX:
@article{Baumberger2014,
  author = {Baumberger, T and Lilley, M D and Resing, J A and Lupton, J E and Baker, E T and Butterfield, D A and Olson, E J and Fruh-Green, G L},
  title = {Understanding a submarine eruption through time series hydrothermal plume sampling of dissolved and particulate constituents: West Mata, 2008-2012},
  journal = {Geochemistry, Geophysics, Geosystems},
  year = {2014},
  volume = {15},
  number = {12},
  pages = {4631--4650},
  doi = {10.1002/2014GC005460}
}
Bernhard JM, Kormas K, Pachiadaki M, Rocke E, Beaudoin DJ, Morrison C, Visscher PT, Cobban A, Starczak VR and Edgcomb VP (2014), "Benthic protists and fungi of Mediterranean deep hypsersaline anoxic basin redoxcline sediments", Frontiers in Microbiology. Vol. 5, pp. 605.
Abstract: Some of the most extreme marine habitats known are the Mediterranean deep hypersaline anoxic basins (DHABs; water depth ∼3500 m). Brines of DHABs are nearly saturated with salt, leading many to suspect they are uninhabitable for eukaryotes. While diverse bacterial and protistan communities are reported from some DHAB water-column haloclines and brines, the existence and activity of benthic DHAB protists have rarely been explored. Here, we report findings regarding protists and fungi recovered from sediments of three DHAB (Discovery, Urania, L' Atalante) haloclines, and compare these to communities from sediments underlying normoxic waters of typical Mediterranean salinity. Halocline sediments, where the redoxcline impinges the seafloor, were studied from all three DHABs. Microscopic cell counts suggested that halocline sediments supported denser protist populations than those in adjacent control sediments. Pyrosequencing analysis based on ribosomal RNA detected eukaryotic ribotypes in the halocline sediments from each of the three DHABs, most of which were fungi. Sequences affiliated with Ustilaginomycotina Basidiomycota were the most abundant eukaryotic signatures detected. Benthic communities in these DHABs appeared to differ, as expected, due to differing brine chemistries. Microscopy indicated that only a low proportion of protists appeared to bear associated putative symbionts. In a considerable number of cases, when prokaryotes were associated with a protist, DAPI staining did not reveal presence of any nuclei, suggesting that at least some protists were carcasses inhabited by prokaryotic scavengers.
BibTeX:
@article{Bernhard2014,
  author = {Bernhard, J M and Kormas, K and Pachiadaki, M and Rocke, E and Beaudoin, D J and Morrison, C and Visscher, P T and Cobban, A and Starczak, V R and Edgcomb, V P},
  title = {Benthic protists and fungi of Mediterranean deep hypsersaline anoxic basin redoxcline sediments},
  journal = {Frontiers in Microbiology},
  year = {2014},
  volume = {5},
  pages = {605},
  doi = {10.3389/fmicb.2014.00605}
}
Brooke S and Ross SW (2014), "First observations of the cold-water coral Lophelia pertusa in mid-Atlantic canyons of the USA", Deep-Sea Research. Part II: Topical Studies in Oceanography. Vol. 104(0), pp. 245-251.
Abstract: The structure-forming, cold-water coral Lophelia pertusa is widely distributed throughout the North Atlantic Ocean and also occurs in the South Atlantic, North Pacific and Indian oceans. This species has formed extensive reefs, chiefly in deep water, along the continental margins of Europe and the United States, particularly off the southeastern U.S. coastline and in the Gulf of Mexico. There were, however, no records of L. pertusa between the continental slope off Cape Lookout, North Carolina (NC) (∼34°N, 76°W), and the rocky Lydonia and Oceanographer canyons off Cape Cod, Massachusetts (MA) (∼40°N, 68°W). During a research cruise in September 2012, L. pertusa colonies were observed on steep walls in both Baltimore and Norfolk canyons. These colonies were all approximately 2 m or less in diameter, usually hemispherical in shape and consisted entirely of live polyps. The colonies were found between 381 m and 434 m with environmental observations of: temperature 6.4–8.6 °C; salinity 35.0–35.6; and dissolved oxygen 2.06–4.41 ml L−1, all of which fall within the range of known L. pertusa distributions. All colonies were observed on vertical walls or underneath overhangs in areas of high current, which differs from observations further south, where L. pertusa colonizes rocky ledges and outcroppings, often forming large bioherms. We discuss observations from Baltimore and Norfolk canyons in the context of the known distribution of this species in the North Atlantic.
BibTeX:
@article{Brooke2014,
  author = {Brooke, S and Ross, S W},
  title = {First observations of the cold-water coral Lophelia pertusa in mid-Atlantic canyons of the USA},
  journal = {Deep-Sea Research. Part II: Topical Studies in Oceanography},
  year = {2014},
  volume = {104},
  number = {0},
  pages = {245--251},
  url = {http://www.sciencedirect.com/science/article/pii/S0967064513002415},
  doi = {10.1016/j.dsr2.2013.06.011}
}
Clague DA, Dreyer BM, Paduan JB, Martin JF, Caress DW, Gill JB, Kelley DS, Thomas H, Portner RA, Delaney JR, Guilderson TP and McGann ML (2014), "Eruptive and tectonic history of the Endeavour Segment, Juan de Fuca Ridge, based on AUV mapping data and lava flow ages", Geochemistry, Geophysics, Geosystems. Vol. 15(8), pp. 3364-3391.
Abstract: High-resolution bathymetric surveys from autonomous underwater vehicles ABE and D. Allan B. were merged to create a coregistered map of 71.7 km(2) of the Endeavour Segment of the Juan de Fuca Ridge. Radiocarbon dating of foraminifera in cores from three dives of remotely operated vehicle Doc Ricketts provide minimum eruption ages for 40 lava flows that are combined with the bathymetric data to outline the eruptive and tectonic history. The ages range from Modern to 10,700 marine-calibrated years before present (yr BP). During a robust magmatic phase from textgreater10,700 yr BP to approximate to 4300 yr BP, flows erupted from an axial high and many flowed textgreater5 km down the flanks; some partly buried adjacent valleys. Axial magma chambers (AMCs) may have been wider than today to supply dike intrusions over a 2 km wide axial zone. Summit Seamount formed by approximate to 4770 yr BP and was subsequently dismembered during a period of extension with little volcanism starting approximate to 4300 yr BP. This tectonic phase with only rare volcanic eruptions lasted until approximate to 2300 yr BP and may have resulted in near-solidification of the AMCs. The axial graben formed by crustal extension during this period of low magmatic activity. Infrequent eruptions occurred on the flanks between 2620-1760 yr BP and within the axial graben since approximate to 1750 yr BP. This most recent phase of limited volcanic and intense hydrothermal activity that began approximate to 2300 yr BP defines a hydrothermal phase of ridge development that coincides with the present-day 1 km wide AMCs and overlying hydrothermal vent fields.
BibTeX:
@article{Clague2014,
  author = {Clague, D A and Dreyer, B M and Paduan, J B and Martin, J F and Caress, D W and Gill, J B and Kelley, D S and Thomas, H and Portner, R A and Delaney, J R and Guilderson, T P and McGann, M L},
  title = {Eruptive and tectonic history of the Endeavour Segment, Juan de Fuca Ridge, based on AUV mapping data and lava flow ages},
  journal = {Geochemistry, Geophysics, Geosystems},
  year = {2014},
  volume = {15},
  number = {8},
  pages = {3364--3391},
  doi = {10.1002/2014GC005415}
}
Demopoulos AWJ, Bourque JR and Frometa J (2014), "Biodiversity and community composition of sediment macrofauna associated with deep-sea Lophelia pertusa habitats in the Gulf of Mexico", Deep-Sea Research. Part I: Oceanographic Research Papers. Vol. 93, pp. 91-103.
Abstract: Scleractinian corals create three-dimensional reefs that provide sheltered refuges, facilitate sediment accumulation, and enhance colonization of encrusting fauna. While heterogeneous coral habitats can harbor high levels of biodiversity, their effect on the community composition within nearby sediments remains unclear, particularly in the deep sea. Sediment macrofauna from deep-sea coral habitats (Lophelia pertusa) and non-coral, background sediments were examined at three sites in the northern Gulf of Mexico (VK826, VK906, MC751, 350–500 m depth) to determine whether macrofaunal abundance, diversity, and community composition near corals differed from background soft-sediments. Macrofaunal densities ranged from 26 to 125 individuals 32 cm−2 and were significantly greater near coral versus background sediments only at VK826. Of the 86 benthic invertebrate taxa identified, 16 were exclusive to near-coral habitats, while 14 were found only in background sediments. Diversity (Fisher's α) and evenness were significantly higher within near-coral sediments only at MC751 while taxon richness was similar among all habitats. Community composition was significantly different both between near-coral and background sediments and among the three primary sites. Polychaetes numerically dominated all samples, accounting for up to 70% of the total individuals near coral, whereas peracarid crustaceans were proportionally more abundant in background sediments (18%) than in those near coral (10%). The reef effect differed among sites, with community patterns potentially influenced by the size of reef habitat. Taxon turnover occurred with distance from the reef, suggesting that reef extent may represent an important factor in structuring sediment communities near L. pertusa. Polychaete communities in both habitats differed from other Gulf of Mexico (GOM) soft sediments based on data from previous studies, and we hypothesize that local environmental conditions found near L. pertusa may influence the macrofaunal community structure beyond the edges of the reef. This study represents the first assessment of L. pertusa-associated sediment communities in the GOM and provides baseline data that can help define the role of transition zones, from deep reefs to soft sediments, in shaping macrofaunal community structure and maintaining biodiversity; this information can help guide future conservation and management activities.
BibTeX:
@article{Demopoulos2014,
  author = {Demopoulos, A W J and Bourque, J R and Frometa, J},
  title = {Biodiversity and community composition of sediment macrofauna associated with deep-sea Lophelia pertusa habitats in the Gulf of Mexico},
  journal = {Deep-Sea Research. Part I: Oceanographic Research Papers},
  year = {2014},
  volume = {93},
  pages = {91--103},
  doi = {10.1016/j.dsr.2014.07.014}
}
Doughty CL, Quattrini AM and Cordes EE (2014), "Insights into the population dynamics of the deep-sea coral genus Paramuricea in the Gulf of Mexico", Biology and Geology of Deep-Sea Coral Ecosystems: Proceedings of the Fifth International Symposium on Deep Sea Corals. Vol. 99(0), pp. 71-82.
Abstract: Species in the genus Paramuricea are among the most common corals in deep waters (textgreater200 m) of the Gulf of Mexico. Paramuricea spp. increase habitat heterogeneity and provide substrate for numerous faunal associates, including ophiuroids that occur on the majority of coral colonies. In light of the Deepwater Horizon oil spill in the Gulf of Mexico, it has become apparent that there is a critical need for data on population dynamics within this genus. To date, at least one species of Paramuricea (P. biscaya) is known to be negatively impacted by the spill. Using remotely operated vehicles from 2009 to 2011, we documented the density and size frequency distributions of Paramuricea across 21 sites at depths of 250–2500 m. Molecular barcoding (mtCOI+igr+MutS) was used to delineate species boundaries among the specimens collected. Results suggested that seven haplotypes are present in the Gulf, and appear to be partially segregated by depth [(type H: was used to delineate species boundaries among the specimens collected. Results suggested that seven haplotypes are present in the Gulf, and appear to be partially segregated by depth [(type H: Paramuricea spp. determined by ROV surveys were mapped onto high-resolution bathymetric data, which confirmed the corals' preference for topographic highs composed of hard substrata. At any one site, densities ranged from 0.043±0.01 (VK906, 380 m) to 1.18±0.81 colonies/m2 (GC852, 1410 m). Mortality and recruitment rates were estimated from size-frequency data combined with estimated growth rates. Mortality rate decreased with size, from approximately 20% and 70% in new recruits of Paramuricea B3 and P. biscaya respectively, to less than 10% in colonies over 40 cm in both species. Recruitment rates were estimated from less than one to over 30 individuals per year per site, but patterns in size-frequency histograms suggest that this process is highly variable at the different sites and at different times. These data illustrate that populations of the slow-growing Paramuricea species are sparsely distributed and exhibit low recruitment rates, making them highly susceptible to anthropogenic threats.
BibTeX:
@article{Doughty2014,
  author = {Doughty, C L and Quattrini, A M and Cordes, E E},
  title = {Insights into the population dynamics of the deep-sea coral genus Paramuricea in the Gulf of Mexico},
  journal = {Biology and Geology of Deep-Sea Coral Ecosystems: Proceedings of the Fifth International Symposium on Deep Sea Corals},
  year = {2014},
  volume = {99},
  number = {0},
  pages = {71--82},
  url = {http://www.sciencedirect.com/science/article/pii/S0967064513002142},
  doi = {10.1016/j.dsr2.2013.05.023}
}
Edgcomb VP and Pachiadaki M (2014), "Ciliates along Oxyclines of Permanently Stratified Marine Water Columns", Journal of Eukaryotic Microbiology. Vol. 61(4), pp. 434-445.
Abstract: Studies of microbial communities in areas of the world where permanent marine water column oxyclines exist suggest they are "hotspots" of microbial activity, and that these water features and the anoxic waters below them are inhabited by diverse protist taxa, including ciliates. These communities have minimal taxonomic overlap with those in overlying oxic water columns. Some ciliate taxa have been detected in multiple locations where these stable water column oxyclines exist; however, differences in such factors as hydrochemistry in the habitats that have been studied suggest local selection for distinct communities. We compare published data on ciliate communities from studies of deep marine water column oxyclines in Caricao Basin, Venezuela, and the Black Sea, with data from coastal, shallower oxycline waters in Framvaren and Mariager fjords, and from several deep-sea hypersaline anoxic basins in the Eastern Mediterranean Sea. Putative symbioses between Bacteria, Archaea, and ciliates observed along these oxyclines suggests a strategy of cooperative metabolism for survival that includes chemosynthetic autotrophy and exchanges of metabolic intermediates or end products between hosts and their prokaryotic partners.
BibTeX:
@article{Edgcomb2014,
  author = {Edgcomb, V P and Pachiadaki, M},
  title = {Ciliates along Oxyclines of Permanently Stratified Marine Water Columns},
  journal = {Journal of Eukaryotic Microbiology},
  year = {2014},
  volume = {61},
  number = {4},
  pages = {434--445},
  doi = {10.1111/jeu.12122}
}
Embley RW, Merle SG, Baker ET, Rubin KH, Lupton JE, Resing JA, Dziak RP, Lilley MD, Chadwick WW, Shank TM, Greene R, Walker SL, Haxel JH, Olson EJ and Baumberger T (2014), "Eruptive modes and hiatus of volcanism at West Mata seamount, NE Lau basin: 1996–2012", Geochemistry, Geophysics, Geosystems. Vol. 15(10), pp. 4093-4115.
Abstract: We present multiple lines of evidence for years to decade-long changes in the location and character of volcanic activity at West Mata seamount in the NE Lau basin over a 16 year period, and a hiatus in summit eruptions from early 2011 to at least September 2012. Boninite lava and pyroclasts were observed erupting from its summit in 2009, and hydroacoustic data from a succession of hydrophones moored nearby show near-continuous eruptive activity from January 2009 to early 2011. Successive differencing of seven multibeam bathymetric surveys of the volcano made in the 1996–2012 period reveals a pattern of extended constructional volcanism on the summit and northwest flank punctuated by eruptions along the volcano's WSW rift zone (WSWRZ). Away from the summit, the volumetrically largest eruption during the observational period occurred between May 2010 and November 2011 at ∼2920 m depth near the base of the WSWRZ. The (nearly) equally long ENE rift zone did not experience any volcanic activity during the 1996–2012 period. The cessation of summit volcanism recorded on the moored hydrophone was accompanied or followed by the formation of a small summit crater and a landslide on the eastern flank. Water column sensors, analysis of gas samples in the overlying hydrothermal plume and dives with a remotely operated vehicle in September 2012 confirmed that the summit eruption had ceased. Based on the historical eruption rates calculated using the bathymetric differencing technique, the volcano could be as young as several thousand years.
BibTeX:
@article{Embley2014,
  author = {Embley, R W and Merle, S G and Baker, E T and Rubin, K H and Lupton, J E and Resing, J A and Dziak, R P and Lilley, M D and Chadwick, W W and Shank, T M and Greene, R and Walker, S L and Haxel, J H and Olson, E J and Baumberger, T},
  title = {Eruptive modes and hiatus of volcanism at West Mata seamount, NE Lau basin: 1996–2012},
  journal = {Geochemistry, Geophysics, Geosystems},
  year = {2014},
  volume = {15},
  number = {10},
  pages = {4093--4115},
  doi = {10.1002/2014GC005387}
}
Feng D, Birgel D, Peckmann J, Roberts HH, Joye SB, Sassen R, Liu X-L, Hinrichs KU and Chen D (2014), "Time integrated variation of sources of fluids and seepage dynamics archived in authigenic carbonates from Gulf of Mexico Gas Hydrate Seafloor Observatory", Chemical Geology. Vol. 385, pp. 129-139.
Abstract: Authigenic carbonate rocks recovered from the Gulf of Mexico Gas Hydrate Seafloor Observatory in Mississippi Canyon block 118 (MC118) at approximately 900 m water depth were studied using mineralogical, bulk geochemical, and lipid biomarker analyses. Carbonate rocks occurred as fractured blocks and nodular masses incorporated in carbonate breccias. The carbonates were comprised mainly of high-Mg-calcite and aragonite. The stable carbon isotope composition (δ13C) of authigenic carbonate varied from − 29.8‰ to − 18.1‰ vs. V-PDB, suggesting a complex mixture of various carbon sources, including dissolved marine inorganic carbon (DIC), oil, as well as methane. Oxygen isotopes (δ18O) varied from + 3.4‰ to + 5.8‰. The observed 18O-enrichment in relation to calculated equilibrium values in the carbonates probably reflects decomposition of gas hydrates. The most abundant lipid biomarkers in the carbonates were isoprenoidal glycerol dibiphytanyl glycerol tetraethers (GDGTs), predominated by GDGT-2 and GDGT-3, which are typically indicators of anaerobic methane oxidizing archaea (ANMEs). Mono- and bicyclic biphytanes (derived after ether cleavage of GDGT-2 and GDGT-3) showed strong 13C-depletion, which is characteristic for ANMEs. Interestingly, large differences between the δ13C values of the archaeal diether archaeol and acyclic biphytane on the one hand and monocyclic biphytane on the other hand suggest the presence of archaea other than ANMEs. Archaeol and GDGT-0 (containing two acyclic biphytane moieties) are commonly assigned to various methanogenic archaea. Where methane seepage activity is intermediate or low within acoustic wipeout zones at the MC118 gas hydrate site nowadays, microbial communities must have coped with changing conditions as well as longer-term fluctuations in oil and gas seepage or the temporary cessation of hydrocarbon flux in the past. The change from methane seepage to oil seepage or vice versa in addition to flux variability apparently favors the establishment of complex prokaryotic communities dominated by archaea. In addition to anaerobic oxidation of methane, local production of methane is apparently prominent at the study site based on the occurrence of biomarkers of methanogens in the authigenic carbonate. This finding adds to the ongoing multidisciplinary effort to better constrain the environment at the MC118 observatory site and to determine the locally dominant biogeochemical processes.
BibTeX:
@article{Feng2014,
  author = {Feng, D and Birgel, D and Peckmann, J and Roberts, H H and Joye, S B and Sassen, R and Liu, X-L and Hinrichs, K -U and Chen, D},
  title = {Time integrated variation of sources of fluids and seepage dynamics archived in authigenic carbonates from Gulf of Mexico Gas Hydrate Seafloor Observatory},
  journal = {Chemical Geology},
  year = {2014},
  volume = {385},
  pages = {129--139},
  doi = {10.1016/j.chemgeo.2014.07.020}
}
Feseker T, Boetius A, Wenzhöfer F, Blandin J, Olu K, Yoerger DR, Camilli R, German CR and de Beer D (2014), "Eruption of a deep-sea mud volcano triggers rapid sediment movement", Nature Communications. Vol. 5, pp. 5385.
Abstract: Submarine mud volcanoes are important sources of methane to the water column. However, the temporal variability of their mud and methane emissions is unknown. Methane emissions were previously proposed to result from a dynamic equilibrium between upward migration and consumption at the seabed by methane-consuming microbes. Here we show non-steady-state situations of vigorous mud movement that are revealed through variations in fluid flow, seabed temperature and seafloor bathymetry. Time series data for pressure, temperature, pH and seafloor photography were collected over 431 days using a benthic observatory at the active Håkon Mosby Mud Volcano. We documented 25 pulses of hot subsurface fluids, accompanied by eruptions that changed the landscape of the mud volcano. Four major events triggered rapid sediment uplift of more than a metre in height, substantial lateral flow of muds at average velocities of 0.4 m per day, and significant emissions of methane and CO2 from the seafloor.
BibTeX:
@article{Feseker2014,
  author = {Feseker, T and Boetius, A and Wenzhöfer, F and Blandin, J and Olu, K and Yoerger, D R and Camilli, R and German, C R and de Beer, D},
  title = {Eruption of a deep-sea mud volcano triggers rapid sediment movement},
  journal = {Nature Communications},
  year = {2014},
  volume = {5},
  pages = {5385},
  doi = {10.1038/ncomms6385}
}
Figueroa DF and Baco AR (2014), "Complete mitochondrial genomes elucidate phylogenetic relationships of the deep-sea octocoral families Coralliidae and Paragorgiidae", Biology and Geology of Deep-Sea Coral Ecosystems: Proceedings of the Fifth International Symposium on Deep Sea Corals. Vol. 99(0), pp. 83-91.
Abstract: In the past decade, molecular phylogenetic analyses of octocorals have shown that the current morphological taxonomic classification of these organisms needs to be revised. The latest phylogenetic analyses show that most octocorals can be divided into three main clades. One of these clades contains the families Coralliidae and Paragorgiidae. These families share several taxonomically important characters and it has been suggested that they may not be monophyletic; with the possibility of the Coralliidae being a derived branch of the Paragorgiidae. Uncertainty exists not only in the relationship of these two families, but also in the classification of the two genera that make up the Coralliidae, Corallium and Paracorallium. Molecular analyses suggest that the genus Corallium is paraphyletic, and it can be divided into two main clades, with the Paracorallium as members of one of these clades. In this study we sequenced the whole mitochondrial genome of five species of Paragorgia and of five species of Corallium to use in a phylogenetic analysis to achieve two main objectives; the first to elucidate the phylogenetic relationship between the Paragorgiidae and Coralliidae and the second to determine whether the genera Corallium and Paracorallium are monophyletic. Our results show that other members of the Coralliidae share the two novel mitochondrial gene arrangements found in a previous study in Corallium konojoi and Paracorallium japonicum; and that the Corallium konojoi arrangement is also found in the Paragorgiidae. Our phylogenetic reconstruction based on all the protein coding genes and ribosomal RNAs of the mitochondrial genome suggest that the Coralliidae are not a derived branch of the Paragorgiidae, but rather a monophyletic sister branch to the Paragorgiidae. While our manuscript was in review a study was published using morphological data and several fragments from mitochondrial genes to redefine the taxonomy of the Coralliidae. Paracorallium was subsumed into Corallium and the genus Hemicorallium was resurrected. This left two disjunct clades as Corallium, making that genus paraphyletic. One of the clades includes the type specimens of Corallium, indicating that clade should remain Corallium. For the other clade, we support the resurrection of the genus Pleurocorallium to fix the paraphyly of Corallium. Based on congruent phylogenies in both studies, the genus Pleurocorallium includes the species C. secundum, C. kishinouyei, C. konojoi, C. elatius, and C. niveum.
BibTeX:
@article{Figueroa2014,
  author = {Figueroa, D F and Baco, A R},
  title = {Complete mitochondrial genomes elucidate phylogenetic relationships of the deep-sea octocoral families Coralliidae and Paragorgiidae},
  journal = {Biology and Geology of Deep-Sea Coral Ecosystems: Proceedings of the Fifth International Symposium on Deep Sea Corals},
  year = {2014},
  volume = {99},
  number = {0},
  pages = {83--91},
  url = {http://www.sciencedirect.com/science/article/pii/S0967064513002312},
  doi = {10.1016/j.dsr2.2013.06.001}
}
Gartman A, Findlay AJ and Luther GW (2014), "Nanoparticulate pyrite and other nanoparticles are a widespread component of hydrothermal vent black smoker emissions", Chemical Geology. Vol. 366, pp. 32-41.
Abstract: The presence of nanoparticulate pyrite is reported in hydrothermal emissions from Rainbow, TAG and Snakepit on the Mid-Atlantic Ridge (MAR). When coupled with previously collected data from East Pacific Rise 9°N (EPR) and Lau Basin, these data demonstrate that pyrite nanoparticles are a widespread component of black smoker emissions from hydrothermal vents and are found in significant concentrations at a fast spreading mid-ocean Ridge (EPR), a back-arc basin (Lau Basin), and a slow spreading mid-ocean Ridge (MAR). The maximum percentage of filtered iron emitted as nanoparticulate pyrite was found to be as high as 25%, 10%, and 5%, respectively. As a widespread component of hydrothermal vent emissions, these nanoparticles may be an important source of iron to the world's oceans. Metals such as Cu and Zn are detected in pyrite-containing aggregates at all sites, and chalcopyrite was a component of nanoparticle aggregates at MAR. Iron containing silicate nanoparticles are also identified, and indicate that nanoparticles other than sulfides should also be considered when determining transport implications of hydrothermal vent emissions. The varied morphologies and the presence of different minerals within these nanoparticles provide insight into their formation and stability.
BibTeX:
@article{Gartman2014,
  author = {Gartman, A and Findlay, A J and Luther, G W},
  title = {Nanoparticulate pyrite and other nanoparticles are a widespread component of hydrothermal vent black smoker emissions},
  journal = {Chemical Geology},
  year = {2014},
  volume = {366},
  pages = {32--41},
  doi = {10.1016/j.chemgeo.2013.12.013}
}
Hu Y, Feng D, Peckmann J, Roberts HH and Chen D (2014), "New insights into cerium anomalies and mechanisms of trace metal enrichment in authigenic carbonate from hydrocarbon seeps", Chemical Geology. Vol. 381(0), pp. 55-66.
Abstract: Authigenic carbonates that form at marine hydrocarbon seeps provide a unique geological archive of past local environmental conditions and pore fluid geochemistry. Recent work on such carbonates revealed variable cerium (Ce) anomalies and anomalous enrichments of certain trace metals. However, the mechanisms accounting for such anomalies remain poorly constrained. Here, we characterize the rare earth element (REE) patterns of carbonate phases and the trace metal patterns of bulk carbonate rocks sampled at three hydrocarbon seeps located at Congo Fan pockmarks (CF) and the Gulf of Mexico sites AC645 and GB425. The analyzed CF, GB425, and AC645 carbonates yielded different REE patterns, displaying positive, no, as well as negative Ce anomalies. The covariation of molybdenum (Mo) with uranium (U), including authigenic Mo (Moauth) and U (Uauth) enrichments as well as (Mo/U)auth ratios proved useful to obtain new insight into the applicability of Ce anomalies to constrain past redox conditions. Trace element patterns suggest that (1) CF carbonates formed in a restricted sulfidic environment, while (2) the AC645 site experienced intermittent oxygenation causing negative Ce anomalies, and (3) environmental conditions were variable at the GB425 mud volcano site. Interestingly, GB425 carbonates show significant Mo, arsenic (As), and antimony (Sb) enrichments with the enrichment factor of As (AsEF) correlating well with the authigenic Fe fraction. These results suggest that iron oxyhydroxides played an important role in the adsorption of Mo, As, and Sb in the water column and their transfer to the sediment. The combination of trace metal and REE geochemistry of authigenic carbonates used here is a promising tool to better assess past variability of redox conditions and biogeochemical processes at marine hydrocarbon seeps.
BibTeX:
@article{Hu2014,
  author = {Hu, Y and Feng, D and Peckmann, J and Roberts, H H and Chen, D},
  title = {New insights into cerium anomalies and mechanisms of trace metal enrichment in authigenic carbonate from hydrocarbon seeps},
  journal = {Chemical Geology},
  year = {2014},
  volume = {381},
  number = {0},
  pages = {55--66},
  url = {http://www.sciencedirect.com/science/article/pii/S0009254114002538},
  doi = {10.1016/j.chemgeo.2014.05.014}
}
Green-Saxena A, Dekas AE, Dalleska NF and Orphan VJ (2014), "Nitrate-based niche differentiation by distinct sulfate-reducing bacteria involved in the anaerobic oxidation of methane", ISME JOURNAL., jan, 2014. Vol. 8(1), pp. 150-163.
Abstract: Diverse associations between methanotrophic archaea (ANME) and sulfate-reducing bacterial groups (SRB) often co-occur in marine methane seeps; however, the ecophysiology of these different symbiotic associations has not been examined. Here, we applied a combination of molecular, geochemical and Fluorescence in situ hybridization (FISH) coupled to nanoscale secondary ion mass spectrometry (FISH-NanoSIMS) analyses of in situ seep sediments and methane-amended sediment incubations from diverse locations (Eel River Basin, Hydrate Ridge and Costa Rican Margin seeps) to investigate the distribution and physiology of a newly identified subgroup of the Desulfobulbaceae (seepDBB) found in consortia with ANME-2c archaea, and compared these with the more commonly observed associations between the same ANME partner and the Desulfobacteraceae (DSS). FISH analyses revealed aggregates of seepDBB cells in association with ANME-2 from both environmental samples and laboratory incubations that are distinct in their structure relative to co-occurring ANME/DSS consortia. ANME/seepDBB aggregates were most abundant in shallow sediment depths below sulfide-oxidizing microbial mats. Depth profiles of ANME/seepDBB aggregate abundance revealed a positive correlation with elevated porewater nitrate relative to ANME/DSS aggregates in all seep sites examined. This relationship with nitrate was supported by sediment microcosm experiments, in which the abundance of ANME/seepDBB was greater in nitrate-amended incubations relative to the unamended control. FISH-NanoSIMS additionally revealed significantly higher N-15-nitrate incorporation levels in individual aggregates of ANME/seepDBB relative to ANME/DSS aggregates from the same incubation. These combined results suggest that nitrate is a geochemical effector of ANME/seepDBB aggregate distribution, and provides a unique niche for these consortia through their utilization of a greater range of nitrogen substrates than the ANME/DSS.
BibTeX:
@article{ISI:000328605200015,
  author = {Green-Saxena, A and Dekas, A E and Dalleska, N F and Orphan, V J},
  title = {Nitrate-based niche differentiation by distinct sulfate-reducing bacteria involved in the anaerobic oxidation of methane},
  journal = {ISME JOURNAL},
  year = {2014},
  volume = {8},
  number = {1},
  pages = {150--163},
  doi = {10.1038/ismej.2013.147}
}
Fallon SJ, Thresher RE and Adkins J (2014), "Age and growth of the cold-water scleractinian Solenosmilia variabilis and its reef on SW Pacific seamounts", CORAL REEFS., mar, 2014. Vol. 33(1), pp. 31-38.
Abstract: Little is known about growth rates of deep-water reef-forming corals or
the rates at which these reefs accumulate. Such information is critical
for determining the resilience of the reefs to anthropogenic impacts
such as trawling and climate change. We radiocarbon date live-caught and
sub-fossil samples of the bioherm-forming coral Solenosmilia variabilis
collected from precisely known depths and locations by means of a
remotely operated vehicle on seamounts south of Tasmania, Australia. The
growth rate of colonies live-caught between 958 and 1,454 m, which spans
most of the depth range of the species locally, ranged from 0.84 to 1.25
mm linear extension yr(-1) and tended to be higher in the deeper-caught
material. Analysis of skeletal microstructure suggests annual deposition
of growth increments near the growing tips, but not closer to the base,
as the skeleton is extended and thickened. Dating of sub-fossil material
indicates S. variabilis has been present on Tasmanian seamounts for at
least the last 47,000 yrs and a reef accumulation rate of 0.27 mm
yr(-1).
BibTeX:
@article{ISI:000330965000004,
  author = {Fallon, S J and Thresher, R E and Adkins, J},
  title = {Age and growth of the cold-water scleractinian Solenosmilia variabilis and its reef on SW Pacific seamounts},
  journal = {CORAL REEFS},
  year = {2014},
  volume = {33},
  number = {1},
  pages = {31--38},
  doi = {10.1007/s00338-013-1097-y}
}
Sapir A, Dillman AR, Connon SA, Grupe BM, Ingels J, Mundo-Ocampo M, Levin LA, Baldwin JG, Orphan VJ and Sternberg PW (2014), "Microsporidia-nematode associations in methane seeps reveal basal fungal parasitism in the deep sea", FRONTIERS IN MICROBIOLOGY., feb, 2014. Vol. 5
Abstract: The deep sea is Earth's largest habitat but little is known about the nature of deep-sea parasitism. In contrast to a few characterized cases of bacterial and protistan parasites, the existence and biological significance of deep-sea parasitic fungi is yet to be understood. Here we report the discovery of a fungus-related parasitic microsporidium, Nematocenator marisprofundi n. gen. n. sp. that infects benthic nematodes at methane seeps on the Pacific Ocean floor. This infection is species-specific and has been temporally and spatially stable over 2 years of sampling, indicating an ecologically consistent host-parasite interaction. A high distribution of spores in the reproductive tracts of infected males and females and their absence from host nematodes' intestines suggests a sexual transmission strategy in contrast to the fecal-oral transmission of most microsporidia. N. mansprofundi targets the host's body wall muscles causing cell lysis, and in severe infection even muscle filament degradation. Phylogenetic analyses placed N. marisprofundi in a novel and basal clade not closely related to any described microsporidia clade, suggesting either that microsporidia-nematode parasitism occurred early in microsporidia evolution or that host specialization occurred late in an ancient deep-sea microsporidian lineage. Our findings reveal that methane seeps support complex ecosystems involving interkingdom interactions between bacteria, nematodes, and parasitic fungi and that microsporidia parasitism exists also in the deep-sea biosphere.
BibTeX:
@article{ISI:000331788900001,
  author = {Sapir, Amir and Dillman, Adler R and Connon, Stephanie A and Grupe, Benjamin M and Ingels, Jeroen and Mundo-Ocampo, Manuel and Levin, Lisa A and Baldwin, James G and Orphan, Victoria J and Sternberg, Paul W},
  title = {Microsporidia-nematode associations in methane seeps reveal basal fungal parasitism in the deep sea},
  journal = {FRONTIERS IN MICROBIOLOGY},
  year = {2014},
  volume = {5},
  doi = {10.3389/fmicb.2014.00043}
}
Becker EL, Cordes EE, Macko SA, Lee RW and Fisher CR (2014), "Spatial patterns of tissue stable isotope contents give insight into the nutritional sources for seep communities on the Gulf of Mexico lower slope", MARINE ECOLOGY PROGRESS SERIES. Vol. 498, pp. 133-U481.
Abstract: In this study, we present the first thorough trophic characterization of cold seep macrofaunal communities on the Gulf of Mexico lower continental slope (textgreater 1000 m depth). We analyzed tissue delta C-13, delta N-15, and delta S-34 of vestimentiferan tubeworms, bathymodiolin mussels, vesicomyid clams, and their associated macrofaunal communities from discrete collections made across the entire lower slope. Over half of macrofauna associated with mussels and about half associated with vestimentiferans had delta C-13 values below -45%. We also observed high spatial variability in the delta C-13 values of entire local communities, and the delta C-13 of associated fauna were significantly correlated with the delta C-13 compositions of the symbiotic species from the same location. These data indicate widespread incorporation of methane-derived carbon in mussel and vestimentiferan communities. This finding was particularly surprising in communities associated with older vestimentiferans, given the low rates of seepage observed in similar communities on the upper slope. On average, delta N-13 values in mussels and their associates were significantly more depleted and more variable than vestimentiferans, clams, and their associates, and there was a significant linear relationship between tissue delta N-15 values of mussels and their associated communities. The tissue delta S-34 values in macrofauna associated with vestimentiferans were more variable and significantly more depleted than mussel associates (delta S-34 = -16.8 to + 19.1% for vestimentiferan associates and delta S-34 = -3.1 to + 20.8% for mussel associates), consistent with higher isotopic fractionation during sulfate reduction in vestimentiferan habitats and a potentially higher nutritional contribution of sulfide-derived organic sulfur in vestimentiferan communities.
BibTeX:
@article{ISI:000332225300011,
  author = {Becker, Erin L and Cordes, Erik E and Macko, Stephen A and Lee, Raymond W and Fisher, Charles R},
  title = {Spatial patterns of tissue stable isotope contents give insight into the nutritional sources for seep communities on the Gulf of Mexico lower slope},
  journal = {MARINE ECOLOGY PROGRESS SERIES},
  year = {2014},
  volume = {498},
  pages = {133--U481},
  doi = {10.3354/meps10598}
}
Meyer JL and Huber JA (2014), "Strain-level genomic variation in natural populations of Lebetimonas from an erupting deep-sea volcano", ISME JOURNAL., apr, 2014. Vol. 8(4), pp. 867-880.
Abstract: Chemolithoautotrophic Epsilonproteobacteria are ubiquitous in sulfidic,
oxygen-poor habitats, including hydrothermal vents, marine oxygen
minimum zones, marine sediments and sulfidic caves and have a
significant role in cycling carbon, hydrogen, nitrogen and sulfur in
these environments. The isolation of diverse strains of
Epsilonproteobacteria and the sequencing of their genomes have revealed
that this group has the metabolic potential to occupy a wide range of
niches, particularly at dynamic deep-sea hydrothermal vents. We expand
on this body of work by examining the population genomics of six strains
of Lebetimonas, a vent-endemic, thermophilic, hydrogen-oxidizing
Epsilonproteobacterium, from a single seamount in the Mariana Arc. Using
Lebetimonas as a model for anaerobic, moderately thermophilic organisms
in the warm, anoxic subseafloor environment, we show that genomic
content is highly conserved and that recombination is limited between
closely related strains. The Lebetimonas genomes are shaped by mobile
genetic elements and gene loss as well as the acquisition of novel
functional genes by horizontal gene transfer, which provide the
potential for adaptation and microbial speciation in the deep sea. In
addition, these Lebetimonas genomes contain two operons of nitrogenase
genes with different evolutionary origins. Lebetimonas expressed nifH
during growth with nitrogen gas as the sole nitrogen source, thus
providing the first evidence of nitrogen fixation in any
Epsilonproteobacteria from deep-sea hydrothermal vents. In this study,
we provide a comparative overview of the genomic potential within the
Nautiliaceae as well as among more distantly related hydrothermal vent
Epsilonproteobacteria to broaden our understanding of microbial
adaptation and diversity in the deep sea.
BibTeX:
@article{ISI:000333189700012,
  author = {Meyer, Julie L and Huber, Julie A},
  title = {Strain-level genomic variation in natural populations of Lebetimonas from an erupting deep-sea volcano},
  journal = {ISME JOURNAL},
  year = {2014},
  volume = {8},
  number = {4},
  pages = {867--880},
  doi = {10.1038/ismej.2013.206}
}
Reeves EP, McDermott JM and Seewald JS (2014), "The origin of methanethiol in midocean ridge hydrothermal fluids", PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA., apr, 2014. Vol. 111(15), pp. 5474-5479.
Abstract: Simple alkyl thiols such as methanethiol (CH3SH) are widely speculated
to form in seafloor hot spring fluids. Putative CH3SH synthesis by
abiotic (nonbiological) reduction of inorganic carbon (CO2 or CO) has
been invoked as an initiation reaction for the emergence of
protometabolism and microbial life in primordial hydrothermal settings.
Thiols are also presumptive ligands for hydrothermal trace metals and
potential fuels for associated microbial communities. In an effort to
constrain sources and sinks of CH3SH in seafloor hydrothermal systems,
we determined for the first time its abundance in diverse hydrothermal
fluids emanating from ultramafic, mafic, and sediment-covered midocean
ridge settings. Our data demonstrate that the distribution of CH3SH is
inconsistent with meta-stable equilibrium with inorganic carbon,
indicating that production by abiotic carbon reduction is more limited
than previously proposed. CH3SH concentrations are uniformly low
(similar to 10(-8) M) in high-temperature fluids (textgreater200 degrees C) from
all unsedimented systems and, in many cases, suggestive of meta-stable
equilibrium with CH4 instead. Associated low-temperature fluids (textless200
degrees C) formed by admixing of seawater, however, are invariably
enriched in CH3SH (up to similar to 10-6 M) along with NH4+ and
low-molecular-weight hydrocarbons relative to high-temperature source
fluids, resembling our observations from a sediment-hosted system. This
strongly implicates thermogenic interactions between upwelling fluids
and microbial biomass or associated dissolved organic matter during
subsurface mixing in crustal aquifers. Widespread thermal degradation of
subsurface organic matter may be an important source of organic
production in unsedimented hydrothermal systems and may influence
microbial metabolic strategies in cooler near-sea-floor and plume
habitats.
BibTeX:
@article{ISI:000334288600024,
  author = {Reeves, Eoghan P and McDermott, Jill M and Seewald, Jeffrey S},
  title = {The origin of methanethiol in midocean ridge hydrothermal fluids},
  journal = {PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA},
  year = {2014},
  volume = {111},
  number = {15},
  pages = {5474--5479},
  doi = {10.1073/pnas.1400643111}
}
Lorenson TD, Wong FL, Dartnell P and Sliter RW (2014), "Greenhouse gases generated from the anaerobic biodegradation of natural offshore asphalt seepages in southern California", GEO-MARINE LETTERS., jun, 2014. Vol. 34(2-3), pp. 281-295.
Abstract: Significant offshore asphaltic deposits with active seepage occur in the
Santa Barbara Channel offshore southern California. The composition and
isotopic signatures of gases sampled from the oil and gas seeps reveal
that the coexisting oil in the shallow subsurface is anaerobically
biodegraded, generating CO2 with secondary CH4 production.
Biomineralization can result in the consumption of as much as 60% by
weight of the original oil, with C-13 enrichment of CO2. Analyses of gas
emitted from asphaltic accumulations or seeps on the seafloor indicate
up to 11% CO2 with C-13 enrichment reaching +24.8aEuro degrees. Methane
concentrations range from less than 30% up to 98% with isotopic
compositions of -34.9 to -66.1aEuro degrees. Higher molecular weight
hydrocarbon gases are present in strongly varying concentrations
reflecting both oil-associated gas and biodegradation; propane is
preferentially biodegraded, resulting in an enriched C-13 isotopic
composition as enriched as -19.5aEuro degrees. Assuming the 132 million
barrels of asphaltic residues on the seafloor represent similar to 40%
of the original oil volume and mass, the estimated gas generated is
5.0x10(10) kg (similar to 76x10(9) m(3)) CH4 and/or 1.4x10(11) kg CO2
over the lifetime of seepage needed to produce the volume of these
deposits. Geologic relationships and oil weathering inferences suggest
the deposits are of early Holocene age or even younger. Assuming an age
of similar to 1,000 years, annual fluxes are on the order of 5.0x10(7)
kg (similar to 76x10(6) m(3)) and/or 1.4x10(8) kg for CH4 and CO2,
respectively. The daily volumetric emission rate (2.1x10(5) m(3)) is
comparable to current CH4 emission from Coal Oil Point seeps (1.5x10(5)
m(3)/day), and may be a significant source of both CH4 and CO2 to the
atmosphere provided that the gas can be transported through the water
column.
BibTeX:
@article{ISI:000336392800014,
  author = {Lorenson, Thomas D and Wong, Florence L and Dartnell, Peter and Sliter, Ray W},
  title = {Greenhouse gases generated from the anaerobic biodegradation of natural offshore asphalt seepages in southern California},
  journal = {GEO-MARINE LETTERS},
  year = {2014},
  volume = {34},
  number = {2-3},
  pages = {281--295},
  doi = {10.1007/s00367-014-0359-1}
}
Winkel M, de Beer D, Lavik G, Peplies J and Mussmann MI (2014), "Close association of active nitrifiers with Beggiatoa mats covering deep-sea hydrothermal sediments", ENVIRONMENTAL MICROBIOLOGY., jun, 2014. Vol. 16(6, SI), pp. 1612-1626.
Abstract: Hydrothermal sediments in the Guaymas Basin are covered by microbial
mats that are dominated by nitrate-respiring and sulphide-oxidizing
Beggiatoa. The presence of these mats strongly correlates with sulphide-
and ammonium-rich fluids venting from the subsurface. Because ammonium
and oxygen form opposed gradients at the sediment surface, we
hypothesized that nitrification is an active process in these Beggiatoa
mats. Using biogeochemical and molecular methods, we measured
nitrification and determined the diversity and abundance of nitrifiers.
Nitrification rates ranged from 74 to 605molNl-1matday-1, which exceeded
those previously measured in hydrothermal plumes and other deep-sea
habitats. Diversity and abundance analyses of archaeal and bacterial
ammonia monooxygenase subunit A genes, archaeal 16S ribosomal RNA
pyrotags and fluorescence in situ hybridization confirmed that ammonia-
and nitrite-oxidizing microorganisms were associated with Beggiatoa
mats. Intriguingly, we observed cells of bacterial and potential
thaumarchaeotal ammonia oxidizers attached to narrow, Beggiatoa-like
filaments. Such a close spatial coupling of nitrification and nitrate
respiration in mats of large sulphur bacteria is novel and may
facilitate mat-internal cycling of nitrogen, thereby reducing loss of
bioavailable nitrogen in deep-sea sediments.
BibTeX:
@article{ISI:000337512000014,
  author = {Winkel, Matthias and de Beer, Dirk and Lavik, Gaute and Peplies, Joerg and Mussmann, Marc I},
  title = {Close association of active nitrifiers with Beggiatoa mats covering deep-sea hydrothermal sediments},
  journal = {ENVIRONMENTAL MICROBIOLOGY},
  year = {2014},
  volume = {16},
  number = {6, SI},
  pages = {1612--1626},
  doi = {10.1111/1462-2920.12316}
}
Cowart DA, Halanych KM, Schaeffer SW and Fisher CR (2014), "Depth-dependent gene flow in Gulf of Mexico cold seep Lamellibrachia tubeworms (Annelida, Siboglinidae)", HYDROBIOLOGIA., sep, 2014. Vol. 736(1), pp. 139-154.
Abstract: Lamellibrachia vestimentiferan tubeworms form aggregations at hydrocarbon cold seeps in the deep Gulf of Mexico (GoM), creating structures that provide living space for other fauna. In the GoM, three Lamellibrachia taxa vary in morphology and depth ranges: Lamellibrachia luymesi (300-950 m), Lamellibrachia sp. 1 (950-2,604 m), and Lamellibrachia sp. 2 (1,175-3,304 m). While Lamellibrachia sp. 2 is consistently identified as a separate species, L. luymesi and sp. 1 cannot be discriminated using barcoding markers cytochrome oxidase subunit 1 (COI) and large ribosomal subunit rDNA (16S). To determine if limited gene flow was a factor in the formation of these taxa, we employed more quickly evolving markers, including mitochondrial cytochrome B (CYTB), hemoglobin subunit B2 intron (HbB2i), and six polymorphic microsatellites; microsatellites were amplified across 45 L. luymesi and sp. 1 individuals. Additionally, we used microsatellites to ask whether populations of Lamellibrachia sp. 1 and sp. 2 show evidence of significant structure. Despite a lack of resolution seen with CYTB and HbB2i, L. luymesi and sp. 1 form genetically differentiated clusters at the cross-amplified microsatellites. Furthermore, we find no evidence for population structure for either Lamellibrachia sp. 1 or sp. 2 across the GoM.
BibTeX:
@article{ISI:000338027700011,
  author = {Cowart, Dominique A and Halanych, Kenneth M and Schaeffer, Stephen W and Fisher, Charles R},
  title = {Depth-dependent gene flow in Gulf of Mexico cold seep Lamellibrachia tubeworms (Annelida, Siboglinidae)},
  journal = {HYDROBIOLOGIA},
  year = {2014},
  volume = {736},
  number = {1},
  pages = {139--154},
  doi = {10.1007/s10750-014-1900-y}
}
Georgian SE, Shedd W and Cordes EE (2014), "High-resolution ecological niche modelling of the cold-water coral Lophelia pertusa in the Gulf of Mexico", MARINE ECOLOGY PROGRESS SERIES. Vol. 506, pp. 145-U454.
Abstract: The niche of many deep-sea species remains poorly resolved despite decades of seafloor exploration. Without better information on the distribution and habitat preference of key species, a complete understanding of the ecology of deep-sea communities will remain unattainable. It is increasingly apparent that cold-water corals are among the dominant foundation species in the deep sea, providing both structurally complex habitat and significant ecosystem services. In this study, the niche and distribution of the cold-water coral Lophelia pertusa in the Gulf of Mexico was evaluated using the maximum entropy (Maxent) approach. Ecological niche models were constructed for a broad region of the northern Gulf of Mexico using data gridded at a spatial resolution of 25 m, including bathymetry, substrate type, export productivity, and aragonite saturation state at depth. Fine-scale models were constructed at a resolution of 5 m using only remotely sensed bathymetric and surface reflectivity data. The broad-scale model performed well, with an area under the curve (AUC) of 0.981. All fine-scale models performed well when verified using training data (average AUC of 0.963) and when validated using independent occurrence data from a new geographic region (average AUC of 0.937). The distribution of L. pertusa in the Gulf of Mexico was found to be controlled primarily by depth, local topography, and availability of hard substrate. While these factors have long been associated with the success of cold-water corals, their relative importance has never been quantified in the Gulf of Mexico, making it historically difficult to precisely delineate L. pertusa's niche and predict its distribution in unexplored regions. Given these results, we suggest that future expeditions combine remotely sensed data with niche modelling techniques to increase the efficiency of deep-sea exploration.
BibTeX:
@article{ISI:000338120000010,
  author = {Georgian, Samuel E and Shedd, William and Cordes, Erik E},
  title = {High-resolution ecological niche modelling of the cold-water coral Lophelia pertusa in the Gulf of Mexico},
  journal = {MARINE ECOLOGY PROGRESS SERIES},
  year = {2014},
  volume = {506},
  pages = {145--U454},
  doi = {10.3354/meps10816}
}
Vetriani C, Voordeckers JW, Crespo-Medina M, O'Brien CE, Giovannelli D and Lutz RA (2014), "Deep-sea hydrothermal vent Epsilonproteobacteria encode a conserved and widespread nitrate reduction pathway (Nap)", ISME JOURNAL., jul, 2014. Vol. 8(7), pp. 1510-1521.
Abstract: Despite the frequent isolation of nitrate-respiring
Epsilonproteobacteria from deep-sea hydrothermal vents, the genes coding
for the nitrate reduction pathway in these organisms have not been
investigated in depth. In this study we have shown that the gene cluster
coding for the periplasmic nitrate reductase complex (nap) is highly
conserved in chemolithoautotrophic, nitrate-reducing
Epsilonproteobacteria from deep-sea hydrothermal vents. Furthermore, we
have shown that the napA gene is expressed in pure cultures of vent
Epsilonproteobacteria and it is highly conserved in microbial
communities collected from deep-sea vents characterized by different
temperature and redox regimes. The diversity of nitrate-reducing
Epsilonproteobacteria was found to be higher in moderate temperature,
diffuse flow vents than in high temperature black smokers or in low
temperatures, substrate-associated communities. As NapA has a high
affinity for nitrate compared with the membrane-bound enzyme, its
occurrence in vent Epsilonproteobacteria may represent an adaptation of
these organisms to the low nitrate concentrations typically found in
vent fluids. Taken together, our findings indicate that nitrate
reduction is widespread in vent Epsilonproteobacteria and provide
insight on alternative energy metabolism in vent microorganisms. The
occurrence of the nap cluster in vent, commensal and pathogenic
Epsilonproteobacteria suggests that the ability of these bacteria to
respire nitrate is important in habitats as different as the deep-sea
vents and the human body.
BibTeX:
@article{ISI:000338213900015,
  author = {Vetriani, Costantino and Voordeckers, James W and Crespo-Medina, Melitza and O'Brien, Charles E and Giovannelli, Donato and Lutz, Richard A},
  title = {Deep-sea hydrothermal vent Epsilonproteobacteria encode a conserved and widespread nitrate reduction pathway (Nap)},
  journal = {ISME JOURNAL},
  year = {2014},
  volume = {8},
  number = {7},
  pages = {1510--1521},
  doi = {10.1038/ismej.2013.246}
}
Toomey DR, Allen RM, Barclay AH, Bell SW, Bromirski PD, Carlson RL, Chen X, Collins JA, Dziak RP, Evers B, Forsyth DW, Gerstoft P, Hooft EEE, Livelybrooks D, Lodewyk JA, Luther DS, McGuire JJ, Schwartz SY, Tolstoy M, Trehu AM, Weirathmueller M and Wilcock WSD (2014), "THE CASCADIA INITIATIVE A Sea Change In Seismological Studies of Subduction Zones", OCEANOGRAPHY., jun, 2014. Vol. 27(2, SI), pp. 138-150.
Abstract: Increasing public awareness that the Cascadia subduction zone in the
Pacific Northwest is capable of great earthquakes (magnitude 9 and
greater) motivates the Cascadia Initiative, an ambitious
onshore/offshore seismic and geodetic experiment that takes advantage of
an amphibious array to study questions ranging from megathrust
earthquakes, to volcanic arc structure, to the formation, deformation
and hydration of the Juan De Fuca and Gorda Plates. Here, we provide an
overview of the Cascadia Initiative, including its primary science
objectives, its experimental design and implementation, and a preview of
how the resulting data are being used by a diverse and growing
scientific community. The Cascadia Initiative also exemplifies how new
technology and community-based experiments are opening up frontiers for
marine science. The new technology shielded ocean bottom seismometers is
allowing more routine investigation of the source zone of megathrust
earthquakes, which almost exclusively lies offshore and in shallow
water. The Cascadia Initiative offers opportunities and accompanying
challenges to a rapidly expanding community of those who use ocean
bottom seismic data.
BibTeX:
@article{ISI:000338758400018,
  author = {Toomey, Douglas R and Allen, Richard M and Barclay, Andrew H and Bell, Samuel W and Bromirski, Peter D and Carlson, Richard L and Chen, Xiaowei and Collins, John A and Dziak, Robert P and Evers, Brent and Forsyth, Donald W and Gerstoft, Peter and Hooft, Emilie E E and Livelybrooks, Dean and Lodewyk, Jessica A and Luther, Douglas S and McGuire, Jeffrey J and Schwartz, Susan Y and Tolstoy, Maya and Trehu, Anne M and Weirathmueller, Michelle and Wilcock, William S D},
  title = {THE CASCADIA INITIATIVE A Sea Change In Seismological Studies of Subduction Zones},
  journal = {OCEANOGRAPHY},
  year = {2014},
  volume = {27},
  number = {2, SI},
  pages = {138--150}
}
Eichinger I, Schmitz-Esser S, Schmid M, Fisher CR and Bright M (2014), "Symbiont-driven sulfur crystal formation in a thiotrophic symbiosis from deep-sea hydrocarbon seeps", ENVIRONMENTAL MICROBIOLOGY REPORTS., aug, 2014. Vol. 6(4, SI), pp. 364-372.
Abstract: The siboglinid tubeworm Sclerolinum contortum symbiosis inhabits
sulfidic sediments at deep-sea hydrocarbon seeps in the Gulf of Mexico.
A single symbiont phylotype in the symbiont-housing organ is inferred
from phylogenetic analyses of the 16S ribosomal ribonucleic acid (16S
rRNA) gene and fluorescent in situ hybridization. The phylotype we
studied here, and a previous study from an arctic hydrocarbon seep
population, reveal identical 16S rRNA symbiont gene sequences. While
sulfide is apparently the energy source for the symbionts (and
ultimately the gutless host), both partners also have to cope with its
toxicity. This study demonstrates abundant large sulfur crystals
restricted to the trophosome area. Based on Raman microspectroscopy and
energy dispersive X-ray analysis, these crystals have the same S8 sulfur
configuration as the recently described small sulfur vesicles formed in
the symbionts. The crystals reside adjacent to the symbionts in the
trophosome. This suggests that their formation is either extra-or
intracellular in symbionts. We propose that formation of these crystals
provides both energy-storage compounds for the symbionts and serves the
symbiosis by removing excess toxic sulfide from host tissues. This
symbiont-mediated sulfide detoxification may have been crucial for the
establishment of thiotrophic symbiosis and continues to remain an
important function of the symbionts.
BibTeX:
@article{ISI:000339334700007,
  author = {Eichinger, Irmgard and Schmitz-Esser, Stephan and Schmid, Markus and Fisher, Charles R and Bright, Monika},
  title = {Symbiont-driven sulfur crystal formation in a thiotrophic symbiosis from deep-sea hydrocarbon seeps},
  journal = {ENVIRONMENTAL MICROBIOLOGY REPORTS},
  year = {2014},
  volume = {6},
  number = {4, SI},
  pages = {364--372},
  doi = {10.1111/1758-2229.12149}
}
Bowles JA, Colman A, McClinton JT, Sinton JM, White SM and Rubin KH (2014), "Eruptive timing and 200 year episodicity at 92 degrees W on the hot spot-influenced Galapagos Spreading Center derived from geomagnetic paleointensity", GEOCHEMISTRY GEOPHYSICS GEOSYSTEMS., jun, 2014. Vol. 15(6), pp. 2211-2224.
Abstract: Eruptive timing in mid-ocean ridge systems is relatively poorly
constrained, despite being an important variable in our understanding of
many mid-ocean ridge processes, including volcanic construction; magma
recharge, flux, and storage; and the stability of hydrothermal systems
and biological communities. Only a handful of absolute eruption
chronologies exist, yet they are essential in understanding how eruptive
timing varies with important controlling variables. To construct an
eruptive history at one location on the Galapagos Spreading Center, we
present age determinations derived from geomagnetic paleointensity. To
aid interpretation of the paleointensity data, we also present results
from on-bottom magnetic anomaly measurements and forward modeling of
topographic-induced magnetic anomalies. Anomalies may lead to a 1-2 mu T
bias in flow-mean paleointensities, which does not significantly affect
the overall interpretation. Paleointensity results for the three
youngest sampled units are indistinguishable, consistent with the flows
being emplaced in relatively rapid succession. Comparisons with models
of geomagnetic field behavior suggest these flows were erupted sometime
in the past 100-200 years. The fourth sampled unit has a significantly
higher paleointensity, consistent with an age of roughly 400 years. The
possible bias in paleointensity data allows for ages as young as similar
to 50 years for the youngest three flows and 200-400 years for the
oldest flow. This age distribution demonstrates an episodicity in the
emplacement of the largest flows at this location, with a 200-300 year
period of relative quiescence between emplacement of the oldest unit and
the three youngest units.
BibTeX:
@article{ISI:000340362500008,
  author = {Bowles, Julie A and Colman, Alice and McClinton, J Timothy and Sinton, John M and White, Scott M and Rubin, Kenneth H},
  title = {Eruptive timing and 200 year episodicity at 92 degrees W on the hot spot-influenced Galapagos Spreading Center derived from geomagnetic paleointensity},
  journal = {GEOCHEMISTRY GEOPHYSICS GEOSYSTEMS},
  year = {2014},
  volume = {15},
  number = {6},
  pages = {2211--2224},
  doi = {10.1002/2014GC005315}
}
Li J, Zhou H, Fang J, Sun Y and Dasgupta S (2014), "Microbial distribution in different spatial positions within the walls of a black sulfide hydrothermal chimney", MARINE ECOLOGY PROGRESS SERIES., aug, 2014. Vol. 508, pp. 67-85.
Abstract: Deep-sea hydrothermal chimneys encompass diverse niches for different
microbial communities with steep environmental gradients. An active
sulfide hydrothermal structure was recovered from the Dudley site of the
Main Endeavour Field in the Juan de Fuca Ridge. Subsamples were taken
from different spatial positions within the chimney wall and analyzed
for mineral composition and microbial biomass and community structure to
illustrate the characteristics of microbial distribution and
environmental constraints. Mineral analysis showed that the chimney was
mainly composed of various Fe-, Zn-, and Cu-rich sulfides, with mineral
composition and abundance varying with spatial position. Microbial
populations in the chimney predominantly consisted of archaeal members
affiliated with the deep-sea hydrothermal vent Euryarchaeota group,
Thermococcales, and Desulfurococcales, as well as bacterial members of
the Gamma-, Epsilon-, and Deltaproteobacteria. Microbial biomass and
composition shifted dramatically and formed different microbial zones
within the chimney walls, from predominantly mesophilic,
sulfur-oxidizing bacterial communities at the outer surfaces to
thermophilic or hyperthermophilic, archaeal sulfur-reducers in the inner
layers of the chimney. Based on microbial physiological characteristics
and their distribution profiles, we inferred that temperature, fluid
geochemistry, and organic compounds probably play an important role in
selecting for and sustaining microbial communities. Furthermore, in situ
temperature regimes within the chimney walls were roughly estimated
based on the temperatures supporting the growth of the dominant
microbial groups.
BibTeX:
@article{ISI:000341168300005,
  author = {Li, Jiangtao and Zhou, Huaiyang and Fang, Jiasong and Sun, Yannan and Dasgupta, Shamik},
  title = {Microbial distribution in different spatial positions within the walls of a black sulfide hydrothermal chimney},
  journal = {MARINE ECOLOGY PROGRESS SERIES},
  year = {2014},
  volume = {508},
  pages = {67--85},
  doi = {10.3354/meps10841}
}
Ferrera I, Banta AB and Reysenbach A-L (2014), "Spatial patterns of Aquificales in deep-sea vents along the Eastern Lau Spreading Center (SW Pacific)", SYSTEMATIC AND APPLIED MICROBIOLOGY., sep, 2014. Vol. 37(6), pp. 442-448.
Abstract: The microbial diversity associated with actively venting deep-sea
hydrothermal deposits is tightly connected to the geochemistry of the
hydrothermal fluids. Although the dominant members of these deposits
drive the structure of the microbial communities, it is less well
understood whether the lower abundance groups are as closely connected
to the geochemical milieu, or driven perhaps by biotic factors such as
microbial community interactions. We used the natural geochemical
gradients that exist in the back-arc basin, Eastern Lau Spreading Center
and Valu-Fa Ridge (ELSC/VFR) in the Southwestern Pacific, to explore
whether the chemolithotrophic Aquificales are influenced by geographical
location, host-rock of the vent field or deposit type. Using a
combination of cloning, DNA fingerprinting (DGGE) and enrichment
culturing approaches, all genera of this order previously described at
marine vents were detected, i.e., Desulfurobacterium,
Thermovibrio,Aquilex, Hydrogenivirga, Persephonella and
Hydrogenothermus. The comparison between clone libraries and DGGE showed
similar patterns of distribution of different Aquificales whereas
results differed for the enrichment cultures that were retrieved.
However, the use of cultivation-based and -independent methods did
provide complementary phylogenetic diversity overview of the Aquificales
in these systems. Together, this survey revealed that the ELSC/VFR
contains some of the largest diversity of Aquificales ever reported at a
deep-sea vent area, that the diversity patterns are tied to the
geography and geochemistry of the system, and that this geochemical
diverse back-arc basin may harbor new members of the Aquificales. (C)
2014 Elsevier GmbH. All rights reserved.
BibTeX:
@article{ISI:000341616500008,
  author = {Ferrera, Isabel and Banta, Amy B and Reysenbach, Anna-Louise},
  title = {Spatial patterns of Aquificales in deep-sea vents along the Eastern Lau Spreading Center (SW Pacific)},
  journal = {SYSTEMATIC AND APPLIED MICROBIOLOGY},
  year = {2014},
  volume = {37},
  number = {6},
  pages = {442--448},
  doi = {10.1016/j.syapm.2014.04.002}
}
Findlay AJ, Gartman A, MacDonald DJ, Hanson TE, Shaw TJ and Luther III GW (2014), "Distribution and size fractionation of elemental sulfur in aqueous environments: The Chesapeake Bay and Mid-Atlantic Ridge", GEOCHIMICA ET COSMOCHIMICA ACTA., oct, 2014. Vol. 142, pp. 334-348.
Abstract: Elemental sulfur is an important intermediate of sulfide oxidation and
may be produced via abiotic and biotic pathways. In this study the
concentration and size fractionation of elemental sulfur were measured
in two different sulfidic marine environments: the Chesapeake Bay and
buoyant hydrothermal vent plumes along the Mid-Atlantic Ridge.
Nanoparticulate sulfur (textless0.2 mu m) was found to comprise up to 90% of
the total elemental sulfur in anoxic deep waters of the Chesapeake Bay.
These data were compared with previous studies of elemental sulfur, and
represent one of the few reports of nanoparticulate elemental sulfur in
the environment. Additionally, a strain of phototrophic sulfide
oxidizing bacteria isolated from the Chesapeake Bay was shown to produce
elemental sulfur as a product of sulfide oxidation. Elemental sulfur
concentrations are also presented from buoyant hydrothermal vent plumes
located along the Mid-Atlantic Ridge. In the Mid-Atlantic Ridge plume,
S-0 concentrations up to 33 mu M were measured in the first meter of
rising plumes at three different vent sites, and nanoparticulate S-0 was
up to 44% of total elemental sulfur present. (C) 2014 Elsevier Ltd. All
rights reserved.
BibTeX:
@article{ISI:000342622400022,
  author = {Findlay, Alyssa J and Gartman, Amy and MacDonald, Daniel J and Hanson, Thomas E and Shaw, Timothy J and Luther III, George W},
  title = {Distribution and size fractionation of elemental sulfur in aqueous environments: The Chesapeake Bay and Mid-Atlantic Ridge},
  journal = {GEOCHIMICA ET COSMOCHIMICA ACTA},
  year = {2014},
  volume = {142},
  pages = {334--348},
  doi = {10.1016/j.gca.2014.07.032}
}
Chadwick J, Keller R, Kamenov G, Yogodzinski G and Lupton J (2014), "The Cobb hot spot: HIMU-DMM mixing and melting controlled by a progressively thinning lithospheric lid", GEOCHEMISTRY GEOPHYSICS GEOSYSTEMS., aug, 2014. Vol. 15(8), pp. 3107-3122.
Abstract: The Cobb Seamount Chain in the northeast Pacific basin records the
composition of the Cobb hot spot for the past 33 Myr, as the migrating
Juan de Fuca Ridge approached and ultimately overran it ca. 0.5 Myr ago.
In this first comprehensive geochemical study of the Cobb chain, major
and trace element compositions and Sr, Nd, Pb, and Hf isotopic ratios
were measured for whole-rock samples from throughout the chain, and He
isotopes were acquired for olivine phenocrysts from one seamount. Trace
element modeling indicates increased melting along the chain over time,
with progressively more depleted lavas as the ridge approached the hot
spot. The isotopic data reveal the first evidence of the high mu
(mu=U-238/Pb-204) (HIMU) mantle component in the north Pacific basin and
are consistent with a progressively decreasing mixing proportion of HIMU
melts relative to those from depleted mid-ocean ridge basalt mantle
(DMM) in the chain over time. Decreasing lithospheric thickness over the
Cobb hot spot due to the approach of the migrating Juan de Fuca ridge
allowed adiabatic melting to continue to shallower depths, leading to
increased melt fractions of the refractory DMM component in the hot spot
and more depleted and MORB-like lavas in the younger Cobb seamounts.
BibTeX:
@article{ISI:000342693400001,
  author = {Chadwick, John and Keller, Randall and Kamenov, George and Yogodzinski, Gene and Lupton, John},
  title = {The Cobb hot spot: HIMU-DMM mixing and melting controlled by a progressively thinning lithospheric lid},
  journal = {GEOCHEMISTRY GEOPHYSICS GEOSYSTEMS},
  year = {2014},
  volume = {15},
  number = {8},
  pages = {3107--3122},
  doi = {10.1002/2014GC005334}
}
Lin H-T, Cowen JP, Olson EJ, Lilley MD, Jungbluth SP, Wilson ST and Rappe MS (2014), "Dissolved hydrogen and methane in the oceanic basaltic biosphere", EARTH AND PLANETARY SCIENCE LETTERS., nov, 2014. Vol. 405, pp. 62-73.
Abstract: The oceanic basaltic crust is the largest aquifer on Earth and has the
potential to harbor substantial subsurface microbial ecosystems, which
hitherto remains largely uncharacterized and is analogous to
extraterrestrial subsurface habitats. Within the sediment-buried 3.5 Myr
old basaltic crust of the eastern Juan de Fuca Ridge flank, the
circulating basement fluids have moderate temperature (similar to 65
degrees C) and low to undetectable dissolved oxygen and nitrate
concentrations. Sulfate, present in high concentrations, is therefore
expected to serve as the major electron acceptor in this subsurface
environment. This study focused on the availability and potential
sources of two important electron donors, methane (CH4) and hydrogen
(H-2), for the subseafloor biosphere. High integrity basement fluids
were collected via fluid delivery lines associated with Integrated Ocean
Drilling Program (IODP) Circulation Obviation Retrofit Kits (CORKs) that
extend from basement depths to outlet ports at the seafloor. Two new
CORKs installed during IODP 327 in 2010, 1362A and 1362B, were sampled
in 2011 and 2013. The two CORKs are superior than earlier style CORKs in
that they are equipped with coated casing and polytetrafluoroethylene
fluid delivery lines, reducing the interaction between casing materials
with the environment. Additional samples were collected from an earlier
style CORK at Borehole 1301A.
The basement fluids are enriched in H-2 (0.05-1.8 mu mol/kg), suggesting
that the ocean basaltic aquifer can support H-2-driven metabolism. The
basement fluids also contain significant amount of CH4 (5-32 mu mol/kg),
revealing CH4 as an available substrate for subseafloor basaltic
habitats. The delta C-13 values of CH4 from the three boreholes ranged
from -22.5 to -58 parts per thousand, while the delta H-2 values ranged
from 316 to 57 parts per thousand. The isotopic compositions of CH4 and
the molecular compositions of hydrocarbons suggest that CH4 in the
basement fluids is of both biogenic and abiotic origins, varying among
sites and sampling times. The delta H-2 values of CH4 in CORK 1301A
fluid samples are much more positive than found in all other marine
environments investigated to date and are best explained by the partial
microbial oxidation of biogenic CH4. In conclusion, our study shows that
CH4 and H-2 are persistently available to fuel the deep biosphere and
that CH4 is both produced and potentially consumed by microorganisms in
the oceanic basement. (C) 2014 Elsevier B.V. All rights reserved.
BibTeX:
@article{ISI:000343625500006,
  author = {Lin, Huei-Ting and Cowen, James P and Olson, Eric J and Lilley, Marvin D and Jungbluth, Sean P and Wilson, Samuel T and Rappe, Michael S},
  title = {Dissolved hydrogen and methane in the oceanic basaltic biosphere},
  journal = {EARTH AND PLANETARY SCIENCE LETTERS},
  year = {2014},
  volume = {405},
  pages = {62--73},
  doi = {10.1016/j.epsl.2014.07.037}
}
Voight JR (2014), "Molluscan species diversity at North Pacific hydrothermal vents: What we know and what it may mean", AMERICAN MALACOLOGICAL BULLETIN., sep, 2014. Vol. 32(2), pp. 267-277.
Abstract: Hydrothermal vents in the deep sea are harsh, temporally unpredictable habitats with what appears to be a distinct fauna. Decades of subsea research with crewed and remote vehicles have generated a list of known species; is the species list complete? Evidence derived from mollusks sampled at hydrothermal vents on the East Pacific Rise (EPR), and Gorda and Juan de Fuca ridges suggests that the answer is yes. A 2006 compilation of hydrothermal vent species based on decades of research is updated and compared to specimens from these three active ridges in collections of the Field Museum of Natural History (FMNH) that resulted from limited collecting activity. Only three dives at each of the two Gorda Ridge vents collected all named species; 90% of the 20 species known from Juan de Fuca Ridge were collected in nine cruises. At the EPR, only 81% of the 43 known species were collected, but differences among the ridges were not significant. The limited FMNH collections increased the known ranges of six species from Juan de Fuca to Gorda Ridge and of nine species on the EPR. In addition, the EPR appears to host more rare species, potentially due to the frequent temporal changes at these vents. Mollusks currently known from each ridge, with their expanded ranges, are listed; the implications of these results for recent discoveries of slow-spreading vent fields are discussed.
BibTeX:
@article{ISI:000343852900015,
  author = {Voight, Janet R},
  title = {Molluscan species diversity at North Pacific hydrothermal vents: What we know and what it may mean},
  journal = {AMERICAN MALACOLOGICAL BULLETIN},
  year = {2014},
  volume = {32},
  number = {2},
  pages = {267--277}
}
Bourbonnais A, Juniper SK, Butterfield DA, Anderson RE and Lehmann MF (2014), "Diversity and abundance of Bacteria and nirS-encoding denitrifiers associated with the Juan de Fuca Ridge hydrothermal system", ANNALS OF MICROBIOLOGY., dec, 2014. Vol. 64(4), pp. 1691-1705.
Abstract: Denitrification, which results in the loss of bioavailable nitrogen-an essential macronutrient for all living organisms-may potentially affect chemosynthetic primary production in hydrothermal vent ecosystems where sub-oxic conditions favorable to denitrification are common. Here we describe the diversity and abundance of denitrifying bacteria in the subsurface biosphere at Axial Volcano and the Endeavour Segment on the Juan de Fuca Ridge using a combination of quantitative polymerase chain reaction assays, and small subunit ribosomal RNA (SSU or 16S rRNA) pyrotag and nitrite reductase (nirS) clone library sequencing methods. Bacterial communities were diverse and dominated by members of the epsilon- and gamma-proteobacteria, including taxonomic groups containing known denitrifiers. Assemblages of denitrifiers that could be evaluated by nirS gene sequence comparisons showed low diversity. The single nirS sequence shared by the two locations, affiliated with a gamma-proteobacteria isolated from estuarine sediments (Pseudomonas sp. BA2), represented more than half of all sequences recovered when clustered at 97 % identity. All other nirS sequences clustered into different taxonomic groups, indicating important differences in denitrifier community membership between the two sites. Total nirS gene abundance was at least two orders of magnitude lower than 16S rRNA abundance. Overall, our results demonstrate that the diversity and abundance of the nirS gene-containing bacterial community are rather low, as might be expected under the extreme conditions encountered in the subsurface biosphere of hydrothermal vent systems, and do not correlate clearly with any environmental variables investigated (i.e., pH, temperature, and H2S, NO3-, NH4+ concentrations).
BibTeX:
@article{ISI:000345292900023,
  author = {Bourbonnais, Annie and Juniper, S Kim and Butterfield, David A and Anderson, Rika E and Lehmann, Moritz F},
  title = {Diversity and abundance of Bacteria and nirS-encoding denitrifiers associated with the Juan de Fuca Ridge hydrothermal system},
  journal = {ANNALS OF MICROBIOLOGY},
  year = {2014},
  volume = {64},
  number = {4},
  pages = {1691--1705},
  doi = {10.1007/s13213-014-0813-3}
}
de Ronde CEJ, Walker SL, Ditchburn RG, Tontini FC, Hannington MD, Merle SG, Timm C, Handler MR, Wysoczanski RJ, Dekov VM, Kamenov GD, Baker ET, Embley RW, Lupton JE and Stoffers P (2014), "The Anatomy of a Buried Submarine Hydrothermal System, Clark Volcano, Kermadec Arc, New Zealand", ECONOMIC GEOLOGY., dec, 2014. Vol. 109(8), pp. 2261-2292.
Abstract: Clark volcano of the Kermadec arc, northeast of New Zealand, is a large stratovolcano comprised of two coalescing volcanic cones; an apparently younger, more coherent, twin-peaked edifice to the northwest and a relatively older, more degraded and tectonized cone to the southeast. High-resolution water column surveys show an active hydrothermal system at the summit of the NW cone largely along a ridge spur connecting the two peaks, with activity also noted at the head of scarps related to sector collapse. Clark is the only known cone volcano along the Kermadec arc to host sulfide mineralization. Volcano-scale gravity and magnetic surveys over Clark show that it is highly magnetized, and that a strong gravity gradient exists between the two edifices. Modeling suggests that a crustal-scale fault lies between these two edifices, with thinner crust beneath the NW cone. Locations of regional earthquake epicenters show a southwest-northeast trend bisecting the two Clark cones, striking northeastward into Tangaroa volcano. Detailed mapping of magnetics above the NW cone summit shows a highly magnetized ring structure 350 m below the summit that is not apparent in the bathymetry; we believe this structure represents the top of a caldera. Oblate zones of low (weak) magnetization caused by hydrothermal fluid upflow, here termed burn holes, form a pattern in the regional magnetization resembling Swiss cheese. Presumably older burn holes occupy the inner margin of the ring structure and show no signs of hydrothermal activity, while younger burn holes are coincident with active venting on the summit. A combination of mineralogy, geochemistry, and seafloor mapping of the NW cone shows that hydrothermal activity today is largely manifest by widespread diffuse venting, with temperatures ranging between 56 degrees and 106 degrees C. Numerous, small (textless= 30 cm high) chimneys populate the summit area, with one site host to the similar to 7-m-tall ``Twin Towers'' chimneys with maximum vent fluid temperatures of 221 degrees C (pH 4.9), consistent with delta S-34(anhydrite-pyrite) values indicating formation temperatures of similar to 228 degrees to 249 degrees C. Mineralization is dominated by pyrite-marcasite-barite-anhydrite. Radiometric dating using the Ra-228/Ra-226 and Ra-226/Ba methods shows active chimneys to be textless20 with most textless2 years old. However, the chimneys at Clark show evidence for mixing with, and remobilizing of, barite as old as 19,000 years. This is consistent with Nd and Sr isotope compositions of Clark chimney and sulfate crust samples that indicate mixing of similar to 40% seawater with a vent fluid derived from low K lavas. Similarly, REE data show the hydrothermal fluids have interacted with a plagioclase-rich source rock. A holistic approach to the study of the Clark hydrothermal system has revealed a two-stage process whereby a caldera-forming volcanic event preceded a later cone-building event. This ensured a protracted (at least 20 ka yrs) history of hydrothermal activity and associated mineral deposition. If we assume at least 200-m-high walls for the postulated (buried) caldera, then hydrothermal fluids would have exited the seafloor 20 ka years ago at least 550 m deeper than they do today, with fluid discharge temperatures potentially much hotter (similar to 350 degrees C). Subsequent to caldera infilling, relatively porous volcaniclastic and other units making up the cone acted as largescale filters, enabling ascending hydrothermal fluids to boil and mix with seawater subseafloor, effectively removing the metals (including remobilized Cu) in solution before they reached the seafloor. This has implications for estimates for the metal inventory of seafloor hydrothermal systems pertaining to arc hydrothermal systems.
BibTeX:
@article{ISI:000345545100011,
  author = {de Ronde, C E J and Walker, S L and Ditchburn, R G and Tontini, F Caratori and Hannington, M D and Merle, S G and Timm, C and Handler, M R and Wysoczanski, R J and Dekov, V M and Kamenov, G D and Baker, E T and Embley, R W and Lupton, J E and Stoffers, P},
  title = {The Anatomy of a Buried Submarine Hydrothermal System, Clark Volcano, Kermadec Arc, New Zealand},
  journal = {ECONOMIC GEOLOGY},
  year = {2014},
  volume = {109},
  number = {8},
  pages = {2261--2292}
}
Pjevac P, Kamyshny Jr. A, Dyksma S and Mussmann M (2014), "Microbial consumption of zero-valence sulfur in marine benthic habitats", ENVIRONMENTAL MICROBIOLOGY., nov, 2014. Vol. 16(11, SI), pp. 3416-3430.
Abstract: Zero-valence sulfur (S-0) is a central intermediate in the marine sulfur
cycle and forms conspicuous accumulations at sediment surfaces,
hydrothermal vents and in oxygen minimum zones. Diverse microorganisms
can utilize S-0, but those consuming S-0 in the environment are largely
unknown. We identified possible key players in S-0 turnover on native or
introduced S-0 in benthic coastal and deep-sea habitats using the 16S
ribosomal RNA approach, (in situ) growth experiments and activity
measurements. In all habitats, the epsilonproteobacterial
Sulfurimonas/Sulfurovum group accounted for a substantial fraction of
the microbial community. Deltaproteobacterial Desulfobulbaceae and
Desulfuromonadales were also frequently detected, indicating S-0
disproportionation and S-0 respiration under anoxic conditions. Sulfate
production from S-0 particles colonized in situ with
Sulfurimonas/Sulfurovum suggested that this group oxidized S-0. We also
show that the type strain Sulfurimonas denitrificans is able to access
cyclooctasulfur (S-8), a metabolic feature not yet demonstrated for
sulfur oxidizers. The ability to oxidize S-0, in particular S-8, likely
facilitates niche partitioning among sulfur oxidizers in habitats with
intense microbial sulfur cycling such as sulfidic sediment surfaces. Our
results underscore the previously overlooked but central role of
Sulfurimonas/Sulfurovum group for conversion of free S-0 at the seafloor
surface.
BibTeX:
@article{ISI:000345631900005,
  author = {Pjevac, Petra and Kamyshny Jr., Alexey and Dyksma, Stefan and Mussmann, Marc},
  title = {Microbial consumption of zero-valence sulfur in marine benthic habitats},
  journal = {ENVIRONMENTAL MICROBIOLOGY},
  year = {2014},
  volume = {16},
  number = {11, SI},
  pages = {3416--3430},
  doi = {10.1111/1462-2920.12410}
}
Beinart RA, Nyholm SV, Dubilier N and Girguis PR (2014), "Intracellular Oceanospirillales inhabit the gills of the hydrothermal vent snail Alviniconcha with chemosynthetic, gamma-Proteobacterial symbionts", ENVIRONMENTAL MICROBIOLOGY REPORTS., dec, 2014. Vol. 6(6), pp. 656-664.
Abstract: Associations between bacteria from the -Proteobacterial order
Oceanospirillales and marine invertebrates are quite common. Members of
the Oceanospirillales exhibit a diversity of interactions with their
various hosts, ranging from the catabolism of complex compounds that
benefit host growth to attacking and bursting host nuclei. Here, we
describe the association between a novel Oceanospirillales phylotype and
the hydrothermal vent snail Alviniconcha. Alviniconcha typically harbour
chemoautotrophic - or epsilon-Proteobacterial symbionts inside their
gill cells. Via fluorescence in situ hybridization and transmission
electron microscopy, we observed an Oceanospirillales phylotype (named
AOP for AlviniconchaOceanospirillales phylotype') in membrane-bound
vacuoles that were separate from the known - or epsilon-Proteobacterial
symbionts. Using quantitative polymerase chain reaction, we surveyed 181
Alviniconcha hosting -Proteobacterial symbionts and 102 hosting
epsilon-Proteobacterial symbionts, and found that the population size of
AOP was always minor relative to the canonical symbionts (median 0.53%
of the total quantified 16S rRNA genes). Additionally, we detected AOP
more frequently in Alviniconcha hosting -Proteobacterial symbionts than
in those hosting epsilon-Proteobacterial symbionts (96% and 5% of
individuals respectively). The high incidence of AOP in -Proteobacteria
hosting Alviniconcha implies that it could play a significant ecological
role either as a host parasite or as an additional symbiont with unknown
physiological capacities.
BibTeX:
@article{ISI:000345702700014,
  author = {Beinart, R A and Nyholm, S V and Dubilier, N and Girguis, P R},
  title = {Intracellular Oceanospirillales inhabit the gills of the hydrothermal vent snail Alviniconcha with chemosynthetic, gamma-Proteobacterial symbionts},
  journal = {ENVIRONMENTAL MICROBIOLOGY REPORTS},
  year = {2014},
  volume = {6},
  number = {6},
  pages = {656--664},
  doi = {10.1111/1758-2229.12183}
}
Smith CR, Bernardino AF, Baco A, Hannides A and Altamira I (2014), "Seven-year enrichment: macrofaunal succession in deep-sea sediments around a 30 tonne whale fall in the Northeast Pacific", MARINE ECOLOGY PROGRESS SERIES. Vol. 515, pp. 133-149.
Abstract: Whale falls cause massive organic and sulfide enrichment of underlying
sediments, yielding energy-rich conditions in oligotrophic deep-sea
ecosystems. While the fauna colonizing whale skeletons has received
substantial study, sediment macrofaunal community response to the
geochemical impacts of deep-sea whale falls remains poorly evaluated. We
present a 7 yr case study of geochemical impacts, macrofaunal community
succession, and chemoautotrophic community persistence in sediments
around a 30 t gray-whale carcass implanted at 1675 m in the
well-oxygenated Santa Cruz Basin on the California margin. The whale
fall yielded intense, patchy organic-carbon enrichment (textgreater15% organic
carbon) and pore-water sulfide enhancement (textgreater5 mM) in nearby sediments
for 6 to 7 yr, supporting a dense assemblage of enrichment opportunists
and chemosymbiotic vesicomyid clams. Faunal succession in the whale-fall
sediments resembled the scavenger-opportunist-sulfophile sequence
previously described for epifaunal communities on sunken whale
skeletons. The intense response of enrichment opportunists functionally
resembles responses to organic loading in shallow-water ecosystems, such
as at sewer outfalls and fish farms. Of 100 macrofaunal species in the
whale-fall sediments, 10 abundant species were unique to whale falls; 6
species were shared with cold seeps, 5 with hydrothermal vents, and 12
with nearby kelp and wood falls. Thus, whale-fall sediments may provide
dispersal stepping stones for some generalized reducing-habitat species
but also support distinct macrofaunal assemblages and contribute
significantly to beta diversity in deep-sea ecosystems.
BibTeX:
@article{ISI:000345703500011,
  author = {Smith, Craig R and Bernardino, Angelo F and Baco, Amy and Hannides, Angelos and Altamira, Iris},
  title = {Seven-year enrichment: macrofaunal succession in deep-sea sediments around a 30 tonne whale fall in the Northeast Pacific},
  journal = {MARINE ECOLOGY PROGRESS SERIES},
  year = {2014},
  volume = {515},
  pages = {133--149},
  doi = {10.3354/meps10955}
}
Breier JA, Sheik CS, Gomez-Ibanez D, Sayre-McCord RT, Sanger R, Rauch C, Coleman M, Bennett SA, Cron BR, Li M, German CR, Toner BM and Dick GJ (2014), "A large volume particulate and water multi-sampler with in situ preservation for microbial and biogeochemical studies", DEEP-SEA RESEARCH PART I-OCEANOGRAPHIC RESEARCH PAPERS., dec, 2014. Vol. 94, pp. 195-206.
Abstract: A new tool was developed for large volume sampling to facilitate marine
microbiology and biogeochemical studies. It was developed for remotely
operated vehicle and hydrocast deployments, and allows for rapid
collection of multiple sample types from the water column and dynamic,
variable environments such as rising hydrothermal plumes. It was used
successfully during a cruise to the hydrothermal vent systems of the
Mid-Cayman Rise. The Suspended Particulate Rosette V2 large volume
multi-sampling system allows for the collection of 14 sample sets per
deployment. Each sample set can include filtered material, whole
(unfiltered) water, and filtrate. Suspended particulate can be collected
on filters up to 142 mm in diameter and pore sizes down to 0.2 mu m.
Filtration is typically at flowrates of 2 L min(-1) For particulate
material, filtered volume is constrained only by sampling time and
filter capacity, with all sample volumes recorded by digital flowmeter.
The suspended particulate filter holders can be filled with preservative
and sealed immediately after sample collection. Up to 2 L of whole
water, filtrate, or a combination of the two, can be collected as part
of each sample set. The system is constructed of plastics with titanium
fasteners and nickel alloy spring loaded seals. There are no ferrous
alloys in the sampling system. Individual sample lines are prefilled
with filtered, deionized water prior to deployment and remain sealed
unless a sample is actively being collected. This system is intended to
facilitate studies concerning the relationship between marine
microbiology and ocean biogeochemistry. (C) 2014 Elsevier Ltd. All
rights reserved.
BibTeX:
@article{ISI:000345820100015,
  author = {Breier, J A and Sheik, C S and Gomez-Ibanez, D and Sayre-McCord, R T and Sanger, R and Rauch, C and Coleman, M and Bennett, S A and Cron, B R and Li, M and German, C R and Toner, B M and Dick, G J},
  title = {A large volume particulate and water multi-sampler with in situ preservation for microbial and biogeochemical studies},
  journal = {DEEP-SEA RESEARCH PART I-OCEANOGRAPHIC RESEARCH PAPERS},
  year = {2014},
  volume = {94},
  pages = {195--206},
  doi = {10.1016/j.dsr.2014.08.008}
}
Horst AJ, Varga RJ, Gee JS and Karson JA (2014), "Diverse magma flow directions during construction of sheeted dike complexes at fast- to superfast-spreading centers", EARTH AND PLANETARY SCIENCE LETTERS., dec, 2014. Vol. 408, pp. 119-131.
Abstract: Dike intrusion is a fundamental process during upper oceanic crustal accretion at fast- to superfast-spreading ridges. Based on the distribution of magma along fast-spreading centers inferred from marine geophysical data, models predict systematic steep flow at magmatically robust segment centers and shallow magma flow toward distal segment ends. Anisotropy of magnetic susceptibility (AMS) fabrics from 48 fully-oriented block samples of dikes from upper oceanic crust exposed at Hess Deep Rift and Pito Deep Rift reveal a wide range of magma flow directions that are not consistent with such simple magma supply models. The AMS is interpreted to arise from distribution anisotropy of titanomagnetite crystals based on weak shape-preferred orientation of opaque oxide and plagioclase crystals generally parallel to AMS maximum eigenvectors. Most dike samples show normal AMS fabrics with maximum eigenvector directions ranging from subvertical to subhorizontal. The distributions of inferred magma flow lineations from maximum eigenvectors show no preferred flow pattern, even after structural correction. We use a Kolmogorov Smirnov test (KS-test) to show that the distribution of bootstrapped flow lineation rakes from Pito Deep are not statistically distinct from Hess Deep, and neither are distinguishable from Oman and Troodos Ophiolite AMS data. Magma flow directions in sheeted dikes from these two seafloor escarpments also do not correlate with available geochemistry in any systematic way as previously predicted. These results indicate distinct compositional sources feed melt that is injected into dikes at fast- to superfast-spreading ridges with no preference for subhorizontal or subvertical magma flow. Collectively, results imply ephemeral melt lenses at different along-axis locations within the continuous axial magma chamber and either direct injection or intermingling of melt from other deeper ridge-centered or off-axis sources. (C) 2014 Elsevier B.V. All rights reserved.
BibTeX:
@article{ISI:000346944000013,
  author = {Horst, A J and Varga, R J and Gee, J S and Karson, J A},
  title = {Diverse magma flow directions during construction of sheeted dike complexes at fast- to superfast-spreading centers},
  journal = {EARTH AND PLANETARY SCIENCE LETTERS},
  year = {2014},
  volume = {408},
  pages = {119--131},
  doi = {10.1016/j.epsl.2014.09.022}
}
Chadwick Jr. WW, Merle SG, Buck NJ, Lavelle JW, Resing JA and Ferrini V (2014), "Imaging of CO2 bubble plumes above an erupting submarine volcano, NW Rota-1, Mariana Arc", GEOCHEMISTRY GEOPHYSICS GEOSYSTEMS., nov, 2014. Vol. 15(11), pp. 4325-4342.
Abstract: NW Rota-1 is a submarine volcano in the Mariana volcanic arc located
similar to 100 km north of Guam. Underwater explosive eruptions driven
by magmatic gases were first witnessed there in 2004 and continued until
at least 2010. During a March 2010 expedition, visual observations
documented continuous but variable eruptive activity at multiple vents
at similar to 560 m depth. Some vents released CO2 bubbles passively and
continuously, while others released CO2 during stronger but intermittent
explosive bursts. Plumes of CO2 bubbles in the water column over the
volcano were imaged by an EM122 (12 kHz) multibeam sonar system.
Throughout the 2010 expedition numerous passes were made over the
eruptive vents with the ship to document the temporal variability of the
bubble plumes and relate them to the eruptive activity on the seafloor,
as recorded by an in situ hydrophone and visual observations. Analysis
of the EM122 midwater data set shows: (1) bubble plumes were present on
every pass over the summit and they rose 200-400 m above the vents but
dissolved before they reached the ocean surface, (2) bubble plume
deflection direction and distance correlate well with ocean current
direction and velocity determined from the ship's acoustic doppler
current profiler, (3) bubble plume heights and volumes were variable
over time and correlate with eruptive intensity as measured by the in
situ hydrophone. This study shows that midwater multibeam sonar data can
be used to characterize the level of eruptive activity and its temporal
variability at a shallow submarine volcano with robust CO2 output.
BibTeX:
@article{ISI:000348060800012,
  author = {Chadwick Jr., William W and Merle, Susan G and Buck, Nathaniel J and Lavelle, J William and Resing, Joseph A and Ferrini, Vicki},
  title = {Imaging of CO2 bubble plumes above an erupting submarine volcano, NW Rota-1, Mariana Arc},
  journal = {GEOCHEMISTRY GEOPHYSICS GEOSYSTEMS},
  year = {2014},
  volume = {15},
  number = {11},
  pages = {4325--4342},
  doi = {10.1002/2014GC005543}
}
Wentrup C, Wendeberg A, Schimak M, Borowski C and Dubilier N (2014), "Forever competent: deep-sea bivalves are colonized by their chemosynthetic symbionts throughout their lifetime", ENVIRONMENTAL MICROBIOLOGY., dec, 2014. Vol. 16(12, SI), pp. 3699-3713.
Abstract: Symbiotic bivalves at hydrothermal vents and cold seeps host
chemosynthetic bacteria intracellularly in gill cells. In bivalves, the
gills grow continuously throughout their lifetime by forming new
filaments. We examined how newly developed gill tissues are colonized in
bivalves with horizontal and vertical symbiont transmission
(Bathymodiolus mussels versus a vesicoymid clam) using fluorescence in
situ hybridization and transmission electron microscopy. Symbiont
colonization was similar in mussels and clams and was independent of the
transmission modes. Symbionts were absent in the growth zones of the
gills, indicating that symbionts colonize newly formed gill filaments de
novo after they are formed and that gill colonization is a continuous
process throughout the host's lifetime. Symbiont abundance and
distribution suggested that colonization is shaped by the developmental
stage of host cells. Self-infection, in which new gill cells are
colonized by symbionts from ontogenetically older gill tissues, may also
play a role. In mussels, symbiont infection led to changes in gill cell
structure similar to those described from other epithelial cells
infected by intracellular pathogens, such as the loss of microvilli. A
better understanding of the factors that affect symbiont colonization of
bivalve gills could provide new insights into interactions between
intracellular bacteria and epithelial tissues.
BibTeX:
@article{ISI:000348463100008,
  author = {Wentrup, Cecilia and Wendeberg, Annelie and Schimak, Mario and Borowski, Christian and Dubilier, Nicole},
  title = {Forever competent: deep-sea bivalves are colonized by their chemosynthetic symbionts throughout their lifetime},
  journal = {ENVIRONMENTAL MICROBIOLOGY},
  year = {2014},
  volume = {16},
  number = {12, SI},
  pages = {3699--3713},
  doi = {10.1111/1462-2920.12597}
}
Jamieson JW, Clague DA and Hannington MD (2014), "Hydrothermal sulfide accumulation along the Endeavour Segment, Juan de Fuca Ridge", Earth and Planetary Science Letters., jan, 2014. Vol. 395(0), pp. 136-148.
Abstract: Hydrothermal sulfide deposits that form on the seafloor are often located by the detection of hydrothermal plumes in the water column, followed by exploration with deep-towed cameras, side-scan sonar imaging, and finally by visual surveys using remotely-operated vehicle or occupied submersible. Hydrothermal plume detection, however, is ineffective for finding hydrothermally-inactive sulfide deposits, which may represent a significant amount of the total sulfide accumulation on the seafloor, even in hydrothermally active settings. Here, we present results from recent high-resolution, autonomous underwater vehicle-based mapping of the hydrothermally-active Endeavour Segment of the Juan de Fuca Ridge, in the Northeast Pacific Ocean. Analysis of the ridge bathymetry resulted in the location of 581 individual sulfide deposits along 24 km of ridge length. Hydrothermal deposits were distinguished from volcanic and tectonic features based on the characteristics of their surface morphology, such as shape and slope angles. Volume calculations for each deposit results in a total volume of 372,500 m3 of hydrothermal sulfide–sulfate–silica material, for an equivalent mass of ∼1.2 Mt of hydrothermal material on the seafloor within the ridge's axial valley, assuming a density of 3.1 g/cm3. Much of this total volume is from previously undocumented inactive deposits outside the main active vent fields. Based on minimum ages of sulfide deposition, the deposits accumulated at a maximum rate of ∼400 t/yr, with a depositional efficiency (proportion of hydrothermal material that accumulates on the seafloor to the total amount hydrothermally mobilized and transported to the seafloor) of ∼5%. The calculated sulfide tonnage represents a four-fold increase over previous sulfide estimates for the Endeavour Segment that were based largely on accumulations from within the active fields. These results suggest that recent global seafloor sulfide resource estimates, which were based mostly on the sizes and distribution of hydrothermally-active deposits, may be similarly underestimating the amount of sulfide along the global submarine neovolcanic zones.
BibTeX:
@article{Jamieson2014,
  author = {Jamieson, J W and Clague, D A and Hannington, M D},
  title = {Hydrothermal sulfide accumulation along the Endeavour Segment, Juan de Fuca Ridge},
  journal = {Earth and Planetary Science Letters},
  year = {2014},
  volume = {395},
  number = {0},
  pages = {136--148},
  url = {http://www.sciencedirect.com/science/article/pii/S0012821X14001873},
  doi = {10.1016/j.epsl.2014.03.035}
}
Kimball JB, Dunbar RB and Guilderson TP (2014), "Oxygen and carbon isotope fractionation in calcitic deep-sea corals: Implications for paleotemperature reconstruction", Chemical Geology. Vol. 381(0), pp. 223-233.
Abstract: Inhabiting areas of the ocean where paleoenvironmental records are sparse, deep-sea corals represent valuable yet largely untapped Holocene records of intermediate and deep ocean variability. δ18O and δ13C were analyzed in nine live-collected deep-sea gorgonian corals (Isididae and Coralliidae) in order to further develop the “lines” paleotemperature method. Least squares linear regression analysis for full lifespan δ18O vs. δ13C (corrected for δ18Owater and δ13CDIC) was utilized to yield equations of the form y = mx + b. δ18O and intercept values were found to be a function of temperature, and to approximate calcite δ18O equilibrium. The corals in this study extend the previously reported calibration (Hill et al., 2011) over a broader range of temperatures from 5 °C to 11.2 °C. When combined with the data from Hill et al. (2011), a new expression for the relationship between the δ18Ointercept value and temperature is proposed: T (°C) = -4.12 ± 0.38 (δ18Ointercept) + 12.32 ± 0.75(R2 = 0.90, p value textless 0.0001) Error estimates are ± 0.7 °C for corals living at cold temperatures (2 °C), ± 1.4 °C in warmer waters (11 °C), and ± 0.5 °C at the mean water temperature of the data set (4.6 °C). The first multi-specimen verification of the “lines” method was performed on three co-located bamboo (Isididae) corals and found to give nearly coincident δ18O intercepts. Detailed intraspecimen sampling reveals δ18O and δ13C isotopic variability within coeval portions of the skeleton. In one specimen, “lines” method analysis was utilized on multiple samples taken from the same temporal increment of the skeleton, yielding multiple δ18O intercepts. Calculated temperatures using the calibration proposed here describe a temperature range of 7.9 to 10.3 °C, which approaches the temperature range of 11.1 ± 0.7 °C at the coral collection location.
BibTeX:
@article{Kimball2014,
  author = {Kimball, J B and Dunbar, R B and Guilderson, T P},
  title = {Oxygen and carbon isotope fractionation in calcitic deep-sea corals: Implications for paleotemperature reconstruction},
  journal = {Chemical Geology},
  year = {2014},
  volume = {381},
  number = {0},
  pages = {223--233},
  url = {http://www.sciencedirect.com/science/article/pii/S0009254114002460},
  doi = {10.1016/j.chemgeo.2014.05.008}
}
Koschinsky A, Kausch M and Borowski C (2014), "Metal concentrations in the tissues of the hydrothermal vent mussel Bathymodiolus: Reflection of different metal sources", Marine Environmental Research. Vol. 95(0), pp. 62-73.
Abstract: Hydrothermal vent mussels of the genus Bathymodiolus are ideally positioned for the use of recording hydrothermal fluxes at the hydrothermal vent sites they inhabit. Barium, Ca, Cd, Co, Cr, Cu, Fe, K, Mg, Mn, Mo, Pb, Sr, and U concentrations in tissue sections of Bathymodiolus mussels from several hydrothermal fields between 15°N and 9°S at the Mid-Atlantic Ridge were determined and compared to the surrounding fluids and solid substrates in the habitats. Elements generally enriched in hydrothermal fluids, such as Fe, Cu, Zn, Pb and Cd, were significantly enriched in the gills and digestive glands of the hydrothermal mussels. The rather small variability of Zn (and Mn) and positive correlation with K and earth alkaline metals may indicate a biological regulation of accumulation. Enrichments of Mo and U in many tissue samples indicate that particulate matter such as hydrothermal mineral particles from the plumes can play a more important role as a metal source than dissolved metals. Highest enrichments of Cu in mussels from the Golden Valley site indicate a relation to the ≥400 °C hot heavy-metal rich fluids emanating in the vicinity. In contrast, mussels from the low-temperature Lilliput field are affected by the Fe oxyhydroxide sediment of their habitat. In a comparison of two different sites within the Logatchev field metal distributions in the tissues reflected small-scale local variations in the metal content of the fluids and the particulate material.
BibTeX:
@article{Koschinsky2014,
  author = {Koschinsky, A and Kausch, M and Borowski, C},
  title = {Metal concentrations in the tissues of the hydrothermal vent mussel Bathymodiolus: Reflection of different metal sources},
  journal = {Marine Environmental Research},
  year = {2014},
  volume = {95},
  number = {0},
  pages = {62--73},
  url = {http://www.sciencedirect.com/science/article/pii/S0141113613002249},
  doi = {10.1016/j.marenvres.2013.12.012}
}
Madin K (2014), "Alvin's animals: scientists in the sub have discovered hundreds of previously unknown species", Oceanus. Vol. 51(1)
BibTeX:
@article{Madin2014,
  author = {Madin, K},
  title = {Alvin's animals: scientists in the sub have discovered hundreds of previously unknown species},
  journal = {Oceanus},
  year = {2014},
  volume = {51},
  number = {1}
}
Moore A, Coogan LA, Costa F and Perfit MR (2014), "Primitive melt replenishment and crystal-mush disaggregation in the weeks preceding the 2005–2006 eruption 9°50′N9°50′N, EPR", Earth and Planetary Science Letters. Vol. 403, pp. 15-26.
Abstract: The 2005–2006 eruption at ∼9°50′N, East Pacific Rise provides an exceptional opportunity to investigate the magma plumbing system beneath a well-studied ridge system. The eruption was preceded by two years of increasingly intense seismicity and occurred from the same location as a previous and well-characterized eruption in 1991–1992. Here we use the crystal cargo of samples from this eruption to investigate magma reservoir processes in the lead-up to the eruption, as well as their temporal relationship to the seismicity that preceded it. Compositional zoning in some plagioclase crystals indicates primitive melt replenishment occurred roughly six weeks or less before the eruption. This replenishing event is seen only in the crystals from the central region of the eruption (9°50′–9°52′N). This is also the area where the most primitive lava compositions are observed and together these observations support models of replenishment being spatially focused. The short time between the input of a more primitive melt and eruption onto the seafloor suggests replenishment likely contributed to triggering the eruption. Rare resorbed plagioclase crystals, and glomerocrysts of plagioclase and olivine, some of which have rims far from equilibrium with their host melt, suggest that disaggregation of a crystal mush occurred within a few days prior to eruption. Interstitial melt from within this mush zone must have been mixed back into the erupted lava—a form of in situ crystallization. Thus, the erupted magmas evolved in a replenished-tapped magma reservoir in which at least a part of the crystallization occurred in situ.
BibTeX:
@article{Moore2014,
  author = {Moore, A and Coogan, L A and Costa, F and Perfit, M R},
  title = {Primitive melt replenishment and crystal-mush disaggregation in the weeks preceding the 2005–2006 eruption 9°50′N9°50′N, EPR},
  journal = {Earth and Planetary Science Letters},
  year = {2014},
  volume = {403},
  pages = {15--26},
  doi = {10.1016/j.epsl.2014.06.015}
}
Nooner SL, Webb SC, Buck WR and Cormier MH (2014), "Post Eruption inflation of the East Pacific Rise at 9 degrees 50 ' N", Geochemistry, Geophysics, Geosystems. Vol. 15(6), pp. 2676-2688.
Abstract: In June 2008, we installed a geodetic network at 9 degrees 50' N on the East Pacific Rise to track the long-term movement of magma following the 2005/6 eruption. This network consists of 10 concrete benchmarks stretching from the ridge to 9 km off-axis. During three campaign-style surveys, measurements of vertical seafloor motions were made at each of these benchmarks by precisely recording ambient seawater pressure as a proxy for seafloor depth with a mobile pressure recorder (MPR). The MPR was deployed using the manned submersible Alvin in 2008 and 2009 and the remotely operated vehicle Jason in 2011. The MPR observations are supplemented with data from a multiyear deployment of continuously recording bottom pressure recorders (BPRs) extending along this segment of the ridge that can record rapid changes in seafloor depth from seafloor eruptions and/or dike intrusions. These measurements show no diking events and up to 12 cm of volcanic inflation that occurred from December 2009 to October 2011 in the area of the 2005/6 eruption. These observations are fit with an inflating point source at a depth of 2.7 km and volume change of 2.3 x 10(6) m(3)/yr located on the ridge axis at approximately 9 degrees 51.166' N, 407 m from our northernmost benchmark, suggesting that the magma chamber underlying this segment of the ridge is being recharged from a deeper source at a rate that is about half the long-term inflation rate observed at Axial Seamount on the Juan de Fuca Ridge. These data represent the second location that active volcanic uplift has been measured on a mid-ocean ridge segment, and the first on a nonhotspot influenced segment.
BibTeX:
@article{Nooner2014,
  author = {Nooner, S L and Webb, S C and Buck, W R and Cormier, M H},
  title = {Post Eruption inflation of the East Pacific Rise at 9 degrees 50 ' N},
  journal = {Geochemistry, Geophysics, Geosystems},
  year = {2014},
  volume = {15},
  number = {6},
  pages = {2676--2688},
  doi = {10.1002/2014GC005389}
}
Panieri G, Aharon P, Sen Gupta BK, Camerlenghi A, Ferrer FP and Cacho I (2014), "Late Holocene Foraminifera of Blake Ridge Diapir: Assemblage Variation and Stable-Isotope Record in gas-hydrate bearing sediments", Marine Geology. Vol. 353(0), pp. 99-107.
Abstract: The presence of gas hydrates on the Blake Ridge diapir, northeastern Atlantic Ocean, offers an opportunity to study the impact of methane seepage on the ecology and geochemistry of benthic foraminifera in the late Holocene. Three push cores, covering a time span of ˜ 1000 yrs, were retrieved from three distinct microhabitats at the top of the diapir at a water depth of ˜ 2150 m: (i) sediments away from seepage (control core), (ii) sediments overlain by clusters of methanotrophic and thiotrophic bivalves, and (iii) chemoautotrophic microbial mats. The foraminiferal assemblages at the two seep sites are marked by a reduction in benthic foraminiferal species diversity, coupled with a near-absence of agglutinated species. However, an opportunistic population rise in CH4- or H2S-tolerant calcareous species (e.g., Globocassidulina subglobosa and Cassidulina laevigata) that utilize the abundant trophic resources at the seeps has led to an increase in the overall assemblage density there. The δ18O and δ13C values of three species of benthic foraminifera - Gyroidinoides laevigatus, Globocassidulina subglobosa, and Uvigerina peregrina - and the planktonic species Globorotalia menardii were acquired from all three cores. The benthic species from methane seeps yield δ13C values of 0.1 to –4.2 (‰VPDB), that are distinctly more 13C-depleted relative to the δ13C of 0.4 to –1.0 (‰VPDB) at the control (off seep) site. The species from a mussel-bed site exhibit more negative δ13C values than those from microbial mats, possibly reflecting different food sources and higher rate of anaerobic oxidation of methane. The positive δ13C values in the paired planktonic species suggest that authigenic carbonate precipitation did not overprint the observed 13C depletions. Hence the probable cause of negative δ13C of benthic foraminifera is primary calcification from Dissolved Inorganic Carbon (DIC) containing mixed carbon fractions from (a) highly 13C-depleted, microbially-oxidized methane and (b) a seawater source.
BibTeX:
@article{Panieri2014,
  author = {Panieri, G and Aharon, Paul and Sen Gupta, B K and Camerlenghi, A and Ferrer, F P and Cacho, I},
  title = {Late Holocene Foraminifera of Blake Ridge Diapir: Assemblage Variation and Stable-Isotope Record in gas-hydrate bearing sediments},
  journal = {Marine Geology},
  year = {2014},
  volume = {353},
  number = {0},
  pages = {99--107},
  url = {http://www.sciencedirect.com/science/article/pii/S0025322714000826},
  doi = {10.1016/j.margeo.2014.03.020}
}
Parnell-Turner R, Cann JR, Smith DK, Schouten H, Yoerger DR, Palmiotto C, Zheleznov A and Bai H (2014), "Sedimentation rates test models of oceanic detachment faulting", Geophysical Research Letters. Vol. 41(20), pp. 7080-7088.
Abstract: Long-lived detachment faults play an important role in the construction of new oceanic crust at slow-spreading mid-oceanic ridges. Although the corrugated surfaces of exposed low-angle faults demonstrate past slip, it is difficult to determine whether a given fault is currently active. If inactive, it is unclear when slip ceased. This judgment is crucial for tectonic reconstructions where detachment faults are present, and for models of plate spreading. We quantify variation in sediment thickness over two corrugated surfaces near 16.5°N at the Mid-Atlantic Ridge using near-bottom Compressed High Intensity Radar Pulse (CHIRP) data. We show that the distribution of sediment and tectonic features at one detachment fault is consistent with slip occurring today. In contrast, another corrugated surface 20 km to the south shows a sediment distribution suggesting that slip ceased ˜150,000 years ago. Data presented here provide new evidence for active detachment faulting, and suggest along-axis variations in fault activity occur over tens of kilometers.
BibTeX:
@article{Parnell-Turner2014,
  author = {Parnell-Turner, R and Cann, J R and Smith, D K and Schouten, H and Yoerger, D R and Palmiotto, C and Zheleznov, A and Bai, H},
  title = {Sedimentation rates test models of oceanic detachment faulting},
  journal = {Geophysical Research Letters},
  year = {2014},
  volume = {41},
  number = {20},
  pages = {7080--7088},
  doi = {10.1002/2014GL061555}
}
Quattrini AM, Etnoyer PJ, Doughty C, English L, Falco R, Remon N, Rittinghouse M and Cordes EE (2014), "A phylogenetic approach to octocoral community structure in the deep Gulf of Mexico", Biology and Geology of Deep-Sea Coral Ecosystems: Proceedings of the Fifth International Symposium on Deep Sea Corals. Vol. 99(0), pp. 92-102.
Abstract: Deep-sea communities are becoming increasingly vulnerable to anthropogenic disturbances, as fishing, hydrocarbon exploration and extraction, and mining activities extend into deeper water. Negative impacts from such activities were recently documented in the Gulf of Mexico (GoM), where the Deepwater Horizon oil spill caused substantial damage to a deep-water octocoral community. Although a faunal checklist and numerous museum records are currently available for the entire GoM, local-scale diversity and assemblage structure of octocoral communities remains unknown, particularly in deep water. On a series of recent cruises (2008–2011) using remotely operated vehicles, 435 octocorals were collected from 33 deep-water sites (250–2500 m) in the northern GoM. To elucidate species boundaries, the extended mitochondrial barcode (COI+igr1+msh) was successfully amplified and sequenced for 422 of these specimens, yielding a total of 64 haplotypes representing at least 52 species. Further, at least 29% of the species collected were either previously not known to occur in the GoM (12 species) or represent new species (at least three species). Overall, species richness at each site was fairly low (1–12 spp.). The greatest species richness occurred at the shallowest () was successfully amplified and sequenced for 422 of these specimens, yielding a total of 64 haplotypes representing at least 52 species. Further, at least 29% of the species collected were either previously not known to occur in the GoM (12 species) or represent new species (at least three species). Overall, species richness at each site was fairly low (1–12 spp.). The greatest species richness occurred at the shallowest (n=8 spp.) and the deepest (2100–2500 m: DC673, n=12 spp., DC583, n=10 spp.) sites, and minimum taxonomic and phylogenetic (Faith's Index) diversity was evident at 600–950 m. This pattern is the opposite of the typical pattern of deep-sea diversity in the GoM, which normally peaks at mid-slope depths. Sorensen's Index of taxonomic β-diversity indicated that six distinct (65–95% dissimilarity) species assemblages corresponded with five depth breaks at ˜325, 425, 600, 1100, and 2100 m. Further assemblage structure was observed within certain depth zones. Of note, within the 425–600 m depth range, species assemblages at the West Florida Slope differed from the other sites, corresponding to an established biogeographic barrier. The phylogenetic approach used in this study provided important insights into the species boundaries of many taxa while demonstrating that evolutionary history plays a critical role in community structure of deep-sea octocorals.
BibTeX:
@article{Quattrini2014,
  author = {Quattrini, A M and Etnoyer, P J and Doughty, C and English, Lisa and Falco, R and Remon, N and Rittinghouse, M and Cordes, E E},
  title = {A phylogenetic approach to octocoral community structure in the deep Gulf of Mexico},
  journal = {Biology and Geology of Deep-Sea Coral Ecosystems: Proceedings of the Fifth International Symposium on Deep Sea Corals},
  year = {2014},
  volume = {99},
  number = {0},
  pages = {92--102},
  url = {http://www.sciencedirect.com/science/article/pii/S096706451300218X},
  doi = {10.1016/j.dsr2.2013.05.027}
}
Salmi MS, Johnson HP, Tivey MA and Hutnak M (2014), "Quantitative estimate of heat flow from a mid-ocean ridge axial valley, Raven field, Juan de Fuca Ridge: Observations and inferences", Journal of Geophysical Research: Solid Earth. Vol. 119(9), pp. 6841-6854.
Abstract: A systematic heat flow survey using thermal blankets within the Endeavour segment of the Juan de Fuca Ridge axial valley provides quantitative estimates of the magnitude and distribution of conductive heat flow at a mid-ocean ridge, with the goal of testing current models of hydrothermal circulation present within newly formed oceanic crust. Thermal blankets were deployed covering an area of 700 by 450 m in the Raven Hydrothermal vent field area located 400 m north of the Main Endeavour hydrothermal field. A total of 176 successful blanket deployment sites measured heat flow values that ranged from 0 to 31 W m−2. Approximately 53% of the sites recorded values lower than 100 mW m−2, suggesting large areas of seawater recharge and advective extraction of lithospheric heat. High heat flow values were concentrated around relatively small “hot spots.” Integration of heat flow values over the Raven survey area gives an estimate of conductive heat output of 0.3 MW, an average of 0.95 W m−2, over the survey area. Fluid circulation cell dimensions and scaling equations allow calculation of a Rayleigh number of approximately 700 in Layer 2A. The close proximity of high and low heat flow areas, coupled with previous estimates of surficial seafloor permeability, argues for the presence of small-scale hydrothermal fluid circulation cells within the high-porosity uppermost crustal layer of the axial seafloor.
BibTeX:
@article{Salmi2014,
  author = {Salmi, M S and Johnson, H P and Tivey, M A and Hutnak, M},
  title = {Quantitative estimate of heat flow from a mid-ocean ridge axial valley, Raven field, Juan de Fuca Ridge: Observations and inferences},
  journal = {Journal of Geophysical Research: Solid Earth},
  year = {2014},
  volume = {119},
  number = {9},
  pages = {6841--6854},
  doi = {10.1002/2014JB011086}
}
Smith DK, Schouten H, Dick HJB, Cann JR, Salters V, Marschall HR, Ji F, Yoerger DR, Sanfilippo A, Parnell-Turner R, Palmiotto C, Zheleznov A, Bai H, Junkin W, Urann B, Dick S, Sulanowska M, Lemmond P and Curry S (2014), "Development and evolution of detachment faulting along 50 km of the Mid-Atlantic Ridge near 16.5°N", Geochemistry, Geophysics, Geosystems. Vol. 15(12), pp. 4692-4711.
Abstract: A multifaceted study of the slow spreading Mid-Atlantic Ridge (MAR) at 16.5°N provides new insights into detachment faulting and its evolution through time. The survey included regional multibeam bathymetry mapping, high-resolution mapping using AUV Sentry, seafloor imaging using the TowCam system, and an extensive rock-dredging program. At different times, detachment faulting was active along ∼50 km of the western flank of the study area, and may have dominated spreading on that flank for the last 5 Ma. Detachment morphologies vary and include a classic corrugated massif, noncorrugated massifs, and back-tilted ridges marking detachment breakaways. High-resolution Sentry data reveal a new detachment morphology; a low-angle, irregular surface in the regional bathymetry is shown to be a finely corrugated detachment surface (corrugation wavelength of only tens of meters and relief of just a few meters). Multiscale corrugations are observed 2–3 km from the detachment breakaway suggesting that they formed in the brittle layer, perhaps by anastomosing faults. The thin wedge of hanging wall lavas that covers a low-angle (6°) detachment footwall near its termination are intensely faulted and fissured; this deformation may be enhanced by the low angle of the emerging footwall. Active detachment faulting currently is limited to the western side of the rift valley. Nonetheless, detachment fault morphologies also are present over a large portion of the eastern flank on crust textgreater2 Ma, indicating that within the last 5 Ma parts of the ridge axis have experienced periods of two-sided detachment faulting.
BibTeX:
@article{Smith2014,
  author = {Smith, D K and Schouten, H and Dick, H J B and Cann, J R and Salters, V and Marschall, H R and Ji, F and Yoerger, D R and Sanfilippo, A and Parnell-Turner, R and Palmiotto, C and Zheleznov, A and Bai, H and Junkin, W and Urann, B and Dick, S and Sulanowska, M and Lemmond, P and Curry, S},
  title = {Development and evolution of detachment faulting along 50 km of the Mid-Atlantic Ridge near 16.5°N},
  journal = {Geochemistry, Geophysics, Geosystems},
  year = {2014},
  volume = {15},
  number = {12},
  pages = {4692--4711},
  doi = {10.1002/2014GC005563}
}
Thal J, Tivey M, Yoerger D, Joens N and Bach W (2014), "Geologic setting of PACManus hydrothermal area - High resolution mapping and in situ observations", Marine Geology. Vol. 355, pp. 98-114.
Abstract: This study presents a systematic analysis and interpretation of autonomous underwater vehicle-based microbathymetry combined with remotely operated vehicle (ROV) video recordings, rock analyses and temperature measurements within the PACManus hydrothermal area located on Pual Ridge in the Bismarck Sea of eastern Manus Basin. The data obtained during research cruise Magellan-06 and So-216 provides a framework for understanding the relationship between the volcanism, tectonism and hydrothermal activity. PACManus is a submarine felsic vocanically-hosted hydrothermal area that hosts multiple vent fields located within several hundred meters of one another but with different fluid chemistries, vent temperatures and morphologies. The total area of hydrothermal activity is estimated to be 20,279 m(2). The microbathymetry maps combined with the ROV video observations allow for precise high-resolution mapping estimates of the areal extents of hydrothermal activity. We find the distribution of hydrothermal fields in the PACManus area is primarily controlled by volcanic features that include lava domes, thick and massive blocky lava flows, breccias and feeder dykes. Spatial variation in the permeability of local volcanic facies appears to control the distribution of venting within a field. We define a three-stage chronological sequence for the volcanic evolution of the PACManus based on lava flow morphology, sediment cover and lava SiO2 concentration. In Stage-1, sparsely to moderately porphyritic dacite lavas (68-69.8 wt.% SiO2) erupted to form domes or cryptodomes. In Stage-2, aphyric lava with slightly lower SiO2 concentrations (67.2-67.9 wt.% SiO2) formed jumbled and pillowed lava flows. In the most recent phase Stage-3, massive blocky lavas with 69 to 72.5 wt% SiO2 were erupted through multiple vents constructing a volcanic ridge identified as the PACManus neovolcanic zone. The transition between these stages may be gradual and related to progressive heating of a silicic magma following a recharge event of hot, mantle-derived melts.
BibTeX:
@article{Thal2014,
  author = {Thal, Janis and Tivey, Maurice and Yoerger, Dana and Joens, Niels and Bach, Wolfgang},
  title = {Geologic setting of PACManus hydrothermal area - High resolution mapping and in situ observations},
  journal = {Marine Geology},
  year = {2014},
  volume = {355},
  pages = {98--114},
  doi = {10.1016/j.margeo.2014.05.011}
}
Thresher R, Althaus F, Adkins J, Gowlett-Holmes K, Alderslade P, Dowdney J, Cho W, Gagnon A, Staples D and McEnnulty F (2014), "Strong Depth-Related Zonation of Megabenthos on a Rocky Continental Margin ( similar to 700-4000 m) off Southern Tasmania, Australia: e85872", PLoS ONE. United Kingdom Vol. 9(1) BioMed Central Ltd..
Abstract: Assemblages of megabenthos are structured in seven depth-related zones between ˜700 and 4000 m on the rocky and topographically complex continental margin south of Tasmania, southeastern Australia. These patterns emerge from analysis of imagery and specimen collections taken from a suite of surveys using photographic and in situ sampling by epibenthic sleds, towed video cameras, an autonomous underwater vehicle and a remotely operated vehicle (ROV). Seamount peaks in shallow zones had relatively low biomass and low diversity assemblages, which may be in part natural and in part due to effects of bottom trawl fishing. Species richness was highest at intermediate depths (1000-1300 m) as a result of an extensive coral reef community based on the bioherm-forming scleractinian Solenosmilia variabilis. However, megabenthos abundance peaked in a deeper, low diversity assemblage at 2000-2500 m. The S. variabilis reef and the deep biomass zone were separated by an extensive dead, sub-fossil S. variabilis reef and a relatively low biomass stratum on volcanic rock roughly coincident with the oxygen minimum layer. Below 2400 m, megabenthos was increasingly sparse, though punctuated by occasional small pockets of relatively high diversity and biomass. Nonetheless, megabenthic organisms were observed in the vast majority of photographs on all seabed habitats and to the maximum depths observed - a sandy plain below 3950 m. Taxonomic studies in progress suggest that the observed depth zonation is based in part on changing species mixes with depth, but also an underlying commonality to much of the seamount and rocky substrate biota across all depths. Although the mechanisms supporting the extraordinarily high biomass in 2000-2500 m depths remains obscure, plausible explanations include equatorwards lateral transport of polar production and/or a response to depth-stratified oxygen availability.
BibTeX:
@article{Thresher2014,
  author = {Thresher, R and Althaus, F and Adkins, J and Gowlett-Holmes, K and Alderslade, Phil and Dowdney, Jo and Cho, W and Gagnon, A and Staples, D and McEnnulty, F},
  title = {Strong Depth-Related Zonation of Megabenthos on a Rocky Continental Margin ( similar to 700-4000 m) off Southern Tasmania, Australia: e85872},
  journal = {PLoS ONE},
  publisher = {BioMed Central Ltd.},
  year = {2014},
  volume = {9},
  number = {1},
  url = {http://norton.whoi.edu/sfxlocal?urlver=Z39.88-2004&rftvalfmt=info:ofi/fmt:kev:mtx:journal&genre=article&sid=ProQ:ProQ%253Apqdibs&atitle=Strong+Depth-Related+Zonation+of+Megabenthos+on+a+Rocky+Continental+Margin+%2528+similar+to+700-4000+m%2529+off+Sou},
  doi = {10.1371/journal.pone.0085872}
}
Tivey MA, Johnson HP, Salmi MS and Hutnak M (2014), "High-resolution near-bottom vector magnetic anomalies over Raven Hydrothermal Field, Endeavour Segment, Juan de Fuca Ridge", Journal of Geophysical Research: Solid Earth. Vol. 119(10), pp. 7389-7403.
Abstract: High-resolution, near-bottom vector magnetic data were collected by remotely operated vehicle Jason over the Raven hydrothermal vent field (47°57.3′N 129°5.75′W) located north of Main Endeavour vent field on the Endeavour segment of the Juan de Fuca Ridge. The survey was part of a comprehensive heat flow study of the Raven site using innovative thermal blanket technology to map the heat flux and crustal fluid pathways around a solitary hydrothermal vent field. Raven hydrothermal activity is presently located along the western axial valley wall, while additional inactive hydrothermal deposits are found to the NW on the upper rift valley wall. Magnetic inversion results show discrete areas of reduced magnetization associated with both active and inactive hydrothermal vent deposits that also show high conductive heat flow. Higher spatial variability in the heat flow patterns compared to the magnetization is consistent with the heat flow reflecting the currently active but ephemeral thermal environment of fluid flow, while crustal magnetization is representative of the static time-averaged effect of hydrothermal alteration. A general NW to SE trend in reduced magnetization across the Raven area correlates closely with the distribution of hydrothermal deposits and heat flux patterns and suggests that the fluid circulation system at depth is likely controlled by local crustal structure and magma chamber geometry. Magnetic gradient tensor components computed from vector magnetic data improve the resolution of the magnetic anomaly source and indicate that the hydrothermally altered zone directly beneath the Raven site is approximately 15 × 106 m3 in volume.
BibTeX:
@article{Tivey2014,
  author = {Tivey, M A and Johnson, H P and Salmi, M S and Hutnak, M},
  title = {High-resolution near-bottom vector magnetic anomalies over Raven Hydrothermal Field, Endeavour Segment, Juan de Fuca Ridge},
  journal = {Journal of Geophysical Research: Solid Earth},
  year = {2014},
  volume = {119},
  number = {10},
  pages = {7389--7403},
  doi = {10.1002/2014JB011223}
}
Walsh JB and Rainnie WD (2014), "Alvin: Ocean Research Submarine", Mechanical Engineering. Vol. 136(8), pp. 28.
BibTeX:
@article{Walsh2014,
  author = {Walsh, Joseph B. and Rainnie, William D.},
  title = {Alvin: Ocean Research Submarine},
  journal = {Mechanical Engineering},
  year = {2014},
  volume = {136},
  number = {8},
  pages = {28}
}
Winner C and Lippsett L (2014), "Bringing Alvin back on board: 'swimmers' are key links between sub and ship", Oceanus. Vol. 51(1)
BibTeX:
@article{Winner2014,
  author = {Winner, C and Lippsett, L},
  title = {Bringing Alvin back on board: 'swimmers' are key links between sub and ship},
  journal = {Oceanus},
  year = {2014},
  volume = {51},
  number = {1}
}
(2014), "Alvin Cleared to Return to Service", Ocean News & Technology. Vol. 20(3), pp. 13.
Abstract: After a 3-year overhaul and major upgrade, the US' deepest-diving research submersible, Alvin, has been cleared to return to work exploring the ocean's depths. The sub has been out of service since December 2010, undergoing a major upgrade that included the replacement of its personnel sphere with a newly fabricated, larger, more capable hull. The Woods Hole Oceanographic Institution operates the Navy-owned sub for the National Deep Submergence Facility on behalf of a consortium of universities and research organizations conducting deep ocean research. The Navy certified Alvin using its Deep Submergence Scope of Certification process, reviewing the design, construction, and materials used to ensure the vehicle performs as expected.
BibTeX:
@article{,,
  title = {Alvin Cleared to Return to Service},
  journal = {Ocean News & Technology},
  year = {2014},
  volume = {20},
  number = {3},
  pages = {13}
}
(2014), "Alvin takes first science dive since overhaul", Ocean News & Technology. Vol. 20(4), pp. 28.
Abstract: Alvin, the nation's only deep-sea research submarine, took its first scientific dive Mar 15, 2014 after a 39- month hiatus and a major overhaul that dramatically upgraded the sub. Because the first dive site was only 320 m deep, the sub was on the bottom about 12 mm later, and Woods Hole Oceanographic Institution scientist Susan Humphris, Alvin pilot Bob Waters, and pilot-in-training Nathan Brown spent the next 5 hrs doing the undersea equivalent of a road test. Humphris described the tests of the Alvin's new command-and-control features that automatically maintain the sub's position, attitude, or heading.
BibTeX:
@article{,,
  title = {Alvin takes first science dive since overhaul},
  journal = {Ocean News & Technology},
  year = {2014},
  volume = {20},
  number = {4},
  pages = {28}
}
Bennett SA, Coleman M, Huber JA, Reddington E, Kinsey JC, McIntyre C, Seewald JS and German CR (2013), "Trophic regions of a hydrothermal plume dispersing away from an ultramafic-hosted vent-system: Von Damm vent-site, Mid-Cayman Rise", Geochemistry, Geophysics, Geosystems. Vol. 14(2), pp. 317-327.
Abstract: Deep-sea ultramafic-hosted vent systems have the potential to provide large amounts of metabolic energy to both autotrophic and heterotrophic microorganisms in their dispersing hydrothermal plumes. Such vent-systems release large quantities of hydrogen and methane to the water column, both of which can be exploited by autotrophic microorganisms. Carbon cycling in these hydrothermal plumes may, therefore, have an important influence on open-ocean biogeochemistry. In this study, we investigated an ultramafic-hosted system on the Mid-Cayman Rise, emitting metal-poor and hydrogen sulfide-, methane-, and hydrogen-rich hydrothermal fluids. Total organic carbon concentrations in the plume ranged between 42.1 and 51.1 μM (background = 43.2 ± 0.7 μM (n = 5)) and near-field plume samples with elevated methane concentrations imply the presence of chemoautotrophic primary production and in particular methanotrophy. In parts of the plume characterized by persistent potential temperature anomalies but lacking elevated methane concentrations, we found elevated organic carbon concentrations of up to 51.1 μM, most likely resulting from the presence of heterotrophic communities, their extracellular products and vent larvae. Elevated carbon concentrations up to 47.4 μM were detected even in far-field plume samples. Within the Von Damm hydrothermal plume, we have used our data to hypothesize a microbial food web in which chemoautotrophy supports a heterotrophic community of microorganisms. Such an active microbial food web would provide a source of labile organic carbon to the deep ocean that should be considered in any future studies evaluating sources and sinks of carbon from hydrothermal venting to the deep ocean.
BibTeX:
@article{Bennett2013,
  author = {Bennett, S A and Coleman, Max and Huber, J A and Reddington, E and Kinsey, J C and McIntyre, C and Seewald, J S and German, C R},
  title = {Trophic regions of a hydrothermal plume dispersing away from an ultramafic-hosted vent-system: Von Damm vent-site, Mid-Cayman Rise},
  journal = {Geochemistry, Geophysics, Geosystems},
  year = {2013},
  volume = {14},
  number = {2},
  pages = {317--327},
  url = {http://dx.doi.org/10.1002/ggge.20063},
  doi = {10.1002/ggge.20063}
}
Brothers LL, Van Dover CL, German CR, Kaiser CL, Yoerger DR, Ruppel CD, Lobecker E, Skarke AD and Wagner JKS (2013), "Evidence for extensive methane venting on the southeastern U.S. Atlantic margin", Geology., jul, 2013. Vol. 41(7), pp. 807-810.
Abstract: We present the first evidence for widespread seabed methane venting along the southeastern United States Atlantic margin beyond the well-known Blake Ridge diapir seep. Recent ship- and autonomous underwater vehicle (AUV)-collected data resolve multiple water-column anomalies (textgreater1000 m height) and extensive new chemosynthetic seep communities at the Blake Ridge and Cape Fear diapirs. These results indicate that multiple, highly localized fluid conduits punctuate the areally extensive Blake Ridge gas hydrate province, and enable the delivery of significant amounts of methane to the water column. Thus, there appears to be an abundance of seabed fluid flux not previously ascribed to the Atlantic margin of the United States.
BibTeX:
@article{Brothers2013,
  author = {Brothers, L L and Van Dover, C L and German, C R and Kaiser, C L and Yoerger, D R and Ruppel, C D and Lobecker, E and Skarke, A D and Wagner, J K S},
  title = {Evidence for extensive methane venting on the southeastern U.S. Atlantic margin},
  journal = {Geology},
  year = {2013},
  volume = {41},
  number = {7},
  pages = {807--810},
  doi = {10.1130/G34217.1}
}
Deschamps A, Tivey MA, Chadwick WW and Embley RW (2013), "Waning magmatic activity along the Southern Explorer Ridge revealed through fault restoration of rift topography", Geochemistry, Geophysics, Geosystems. Vol. 14(5), pp. 1609-1625.
Abstract: We combine high-resolution bathymetry acquired using the Autonomous Underwater Vehicle ABE with digital seafloor imagery collected using the remotely operated vehicle ROPOS across the axial valley of the Southern Explorer Ridge (SER) to infer the recent volcanic and tectonic processes. The SER is an intermediate spreading ridge located in the northeast Pacific. It hosts the Magic Mountain hydrothermal vent. We reconstruct the unfaulted seafloor terrain at SER based on calculations of the vertical displacement field and fault parameters. The vertical changes between the initial and the restored topographies reflect the integrated effects of volcanism and tectonism on relief-forming processes over the last 11,000–14,000 years. The restored topography indicates that the axial morphology evolved from a smooth constructional dome textgreater500 m in diameter, to a fault-bounded graben, ˜500 m wide and 30–70 m deep. This evolution has been accompanied by changes in eruptive rate, with deposition of voluminous lobate and sheet flows when the SER had a domed morphology, and limited-extent low-effusion rate pillow eruptions during graben development. Most of the faults shaping the present axial valley postdate the construction of the dome. Our study supports a model of cyclic volcanism at the SER with periods of effusive eruptions flooding the axial rift, centered on the broad plateau at the summit of the ridge, followed by a decrease in eruptive activity and a subsequent dominance of tectonic processes, with minor low-effusion rate eruptions confined to the axial graben. The asymmetric shape of the axial graben supports an increasing role of extensional processes, with a component of simple shear in the spreading processes.
BibTeX:
@article{Deschamps2013,
  author = {Deschamps, A and Tivey, M A and Chadwick, W W and Embley, R W},
  title = {Waning magmatic activity along the Southern Explorer Ridge revealed through fault restoration of rift topography},
  journal = {Geochemistry, Geophysics, Geosystems},
  year = {2013},
  volume = {14},
  number = {5},
  pages = {1609--1625},
  url = {http://dx.doi.org/10.1002/ggge.20110},
  doi = {10.1002/ggge.20110}
}
Feng D, Cordes EE, Roberts HH and Fisher CR (2013), "A comparative study of authigenic carbonates from mussel and tubeworm environments: Implications for discriminating the effects of tubeworms", Deep-Sea Research. Part I: Oceanographic Research Papers. Vol. 75(0), pp. 110-118.
Abstract: The Gulf of Mexico hydrocarbon seeps are often populated by dense mussel beds and tubeworm aggregations, as well as exposed authigenic carbonate outcrops. Previous studies suggest the activity of mussels and tubeworms could influence the sediment geochemistry of their habitats, resulting in variations in the stable carbon isotopes of the associated carbonates. However, this conclusion was based on the analyses of samples from a single site. To better understand whether there are consistent differences in the geochemical environments of mussels and tubeworms, mineralogical and stable isotopic compositions of authigenic carbonates from mussel and tubeworm environments from four seep sites were analyzed. The studied sites span a depth range of 1200 m to 2800 m on the northern Gulf of Mexico continental slope. We found that carbonate samples from tubeworm environments were more prone to contain aragonite whereas carbonates from mussel environments were more likely to have calcite. This finding supports the hypothesis that vestimentiferans release sulfate across their roots into the pore waters of the surrounding sediments, a process that could generate a locally sulfate-enriched environment that favors the precipitation of aragonite instead of calcite. Moreover, the δ13C values of tubeworm carbonates are generally lighter than that of mussel carbonates from the same site, which is consistent with the fact that tubeworms are fueling extra subsurface methane oxidation through the release of sulfate into the sediment. Such a process, consequently, enriches the subsurface dissolved inorganic carbon pool with light carbon derived from the seeping hydrocarbons. Taken together, our data suggest that tubeworms could produce a carbon isotope shift that is sufficient to influence the sediment geochemistry of their immediate area, and that this impact is reflected in the associated authigenic carbonates.
BibTeX:
@article{Feng2013,
  author = {Feng, D and Cordes, E E and Roberts, H H and Fisher, C R},
  title = {A comparative study of authigenic carbonates from mussel and tubeworm environments: Implications for discriminating the effects of tubeworms},
  journal = {Deep-Sea Research. Part I: Oceanographic Research Papers},
  year = {2013},
  volume = {75},
  number = {0},
  pages = {110--118},
  url = {http://www.sciencedirect.com/science/article/pii/S0967063713000435},
  doi = {10.1016/j.dsr.2013.02.002}
}
Hansen LN, Cheadle MJ, John BE, Swapp SM, Dick HJB, Tucholke BE and Tivey MA (2013), "Mylonitic deformation at the Kane oceanic core complex: Implications for the rheological behavior of oceanic detachment faults", Geochemistry, Geophysics, Geosystems. Vol. 14, pp. 3085-3108.
Abstract: The depth extent, strength, and composition of oceanic detachment faults remain poorly understood because the grade of deformation-related fabrics varies widely among sampled oceanic core complexes (OCCs). We address this issue by analyzing fault rocks collected from the Kane oceanic core complex at 23°30′N on the Mid-Atlantic Ridge. A portion of the sample suite was collected from a younger fault scarp that cuts the detachment surface and exposes the interior of the most prominent dome. The style of deformation was assessed as a function of proximity to the detachment surface, revealing a ∼450 m thick zone of high-temperature mylonitization overprinted by a ∼200 m thick zone of brittle deformation. Geothermometry of deformed gabbros demonstrates that crystal-plastic deformation occurred at temperatures textgreater700°C. Analysis of the morphology of the complex in conjunction with recent thermochronology suggests that deformation initiated at depths of ∼7 km. Thus we suggest the detachment system extended into or below the brittle-plastic transition (BPT). Microstructural evidence suggests that gabbros and peridotites with high-temperature fabrics were dominantly deforming by dislocation-accommodated processes and diffusion creep. Recrystallized grain size piezometry yields differential stresses consistent with those predicted by dry-plagioclase flow laws. The temperature and stress at the BPT determined from laboratory-derived constitutive models agree well with the lowest temperatures and highest stresses estimated from gabbro mylonites. We suggest that the variation in abundance of mylonites among oceanic core complexes can be explained by variation in the depth of the BPT, which depends to a first order on the thermal structure and water content of newly forming oceanic lithosphere.
BibTeX:
@article{Hansen2013,
  author = {Hansen, L N and Cheadle, M J and John, B E and Swapp, S M and Dick, H J B and Tucholke, B E and Tivey, M A},
  title = {Mylonitic deformation at the Kane oceanic core complex: Implications for the rheological behavior of oceanic detachment faults},
  journal = {Geochemistry, Geophysics, Geosystems},
  year = {2013},
  volume = {14},
  pages = {3085--3108},
  doi = {10.1002/ggge.20184}
}
Jungbluth SP, Grote J, Lin H-T, Cowen JP and Rappe MS (2013), "Microbial diversity within basement fluids of the sediment-buried Juan de Fuca Ridge flank", ISME JOURNAL., jan, 2013. Vol. 7(1), pp. 161-172.
Abstract: Despite its immense size, logistical and methodological constraints have largely limited microbiological investigations of the subseafloor basement biosphere. In this study, a unique sampling system was used to collect fluids from the subseafloor basaltic crust via a Circulation Obviation Retrofit Kit (CORK) observatory at Integrated Ocean Drilling Program borehole 1301A, located at a depth of 2667 m in the Pacific Ocean on the eastern flank of the Juan de Fuca Ridge. Here, a fluid delivery line directly accesses a 3.5 million years old basalt-hosted basement aquifer, overlaid by 262 m of sediment, which serves as a barrier to direct exchange with bottom seawater. At an average of 1.2 x 10(4) cells ml(-1), microorganisms in borehole fluids were nearly an order of magnitude less abundant than in surrounding bottom seawater. Ribosomal RNA genes were characterized from basement fluids, providing the first snapshots of microbial community structure using a high-integrity fluid delivery line. Interestingly, microbial communities retrieved from different CORKs (1026B and 1301A) nearly a decade apart shared major community members, consistent with hydrogeological connectivity. However, over three sampling years, the dominant gene clone lineage changed from relatives of Candidatus Desulforudis audaxviator within the bacterial phylum Firmicutes in 2008 to the Miscellaneous Crenarchaeotic Group in 2009 and a lineage within the JTB35 group of Gammaproteobacteria in 2010, and statistically significant variation in microbial community structure was observed. The enumeration of different phylogenetic groups of cells within borehole 1301A fluids supported our observation that the deep subsurface microbial community was temporally dynamic. The ISME Journal (2013) 7, 161-172; doi:10.1038/ismej.2012.73; published online 12 July 2012
BibTeX:
@article{ISI:000313236000014,
  author = {Jungbluth, Sean P and Grote, Jana and Lin, Huei-Ting and Cowen, James P and Rappe, Michael S},
  title = {Microbial diversity within basement fluids of the sediment-buried Juan de Fuca Ridge flank},
  journal = {ISME JOURNAL},
  year = {2013},
  volume = {7},
  number = {1},
  pages = {161--172},
  doi = {10.1038/ismej.2012.73}
}
MacGregor BJ, Biddle JF, Siebert JR, Staunton E, Hegg EL, Matthysse AG and Teske A (2013), "Why Orange Guaymas Basin Beggiatoa spp. Are Orange: Single-Filament-Genome-Enabled Identification of an Abundant Octaheme Cytochrome with Hydroxylamine Oxidase, Hydrazine Oxidase, and Nitrite Reductase Activities", APPLIED AND ENVIRONMENTAL MICROBIOLOGY., feb, 2013. Vol. 79(4), pp. 1183-1190.
Abstract: Orange, white, and yellow vacuolated Beggiatoaceae filaments are
visually dominant members of microbial mats found near sea floor
hydrothermal vents and cold seeps, with orange filaments typically
concentrated toward the mat centers. No marine vacuolate Beggiatoaceae
are yet in pure culture, but evidence to date suggests they are
nitrate-reducing, sulfide-oxidizing bacteria. The nearly complete genome
sequence of a single orange Beggiatoa (''Candidatus Maribeggiatoa'')
filament from a microbial mat sample collected in 2008 at a hydrothermal
site in Guaymas Basin (Gulf of California, Mexico) was recently
obtained. From this sequence, the gene encoding an abundant soluble
orange-pigmented protein in Guaymas Basin mat samples (collected in
2009) was identified by microcapillary reverse-phase high-performance
liquid chromatography (HPLC) nano-electrospray tandem mass spectrometry
(mu LC-MS-MS) of a pigmented band excised from a denaturing
polyacrylamide gel. The predicted protein sequence is related to a large
group of octaheme cytochromes whose few characterized representatives
are hydroxylamine or hydrazine oxidases. The protein was partially
purified and shown by in vitro assays to have hydroxylamine oxidase,
hydrazine oxidase, and nitrite reductase activities. From what is known
of Beggiatoaceae physiology, nitrite reduction is the most likely in
vivo role of the octaheme protein, but future experiments are required
to confirm this tentative conclusion. Thus, while present-day genomic
and proteomic techniques have allowed precise identification of an
abundant mat protein, and its potential activities could be assayed,
proof of its physiological role remains elusive in the absence of a pure
culture that can be genetically manipulated.
BibTeX:
@article{ISI:000314891500014,
  author = {MacGregor, Barbara J and Biddle, Jennifer F and Siebert, Jason R and Staunton, Eric and Hegg, Eric L and Matthysse, Ann G and Teske, Andreas},
  title = {Why Orange Guaymas Basin Beggiatoa spp. Are Orange: Single-Filament-Genome-Enabled Identification of an Abundant Octaheme Cytochrome with Hydroxylamine Oxidase, Hydrazine Oxidase, and Nitrite Reductase Activities},
  journal = {APPLIED AND ENVIRONMENTAL MICROBIOLOGY},
  year = {2013},
  volume = {79},
  number = {4},
  pages = {1183--1190},
  doi = {10.1128/AEM.02538-12}
}
Frank KL, Rogers DR, Olins HC, Vidoudez C and Girguis PR (2013), "Characterizing the distribution and rates of microbial sulfate reduction at Middle Valley hydrothermal vents", ISME JOURNAL., jul, 2013. Vol. 7(7), pp. 1391-1401.
Abstract: Few studies have directly measured sulfate reduction at hydrothermal
vents, and relatively little is known about how environmental or
ecological factors influence rates of sulfate reduction in vent
environments. A better understanding of microbially mediated sulfate
reduction in hydrothermal vent ecosystems may be achieved by integrating
ecological and geochemical data with metabolic rate measurements. Here
we present rates of microbially mediated sulfate reduction from three
distinct hydrothermal vents in the Middle Valley vent field along the
Juan de Fuca Ridge, as well as assessments of bacterial and archaeal
diversity, estimates of total biomass and the abundance of functional
genes related to sulfate reduction, and in situ geochemistry. Maximum
rates of sulfate reduction occurred at 90 degrees C in all three
deposits. Pyrosequencing and functional gene abundance data revealed
differences in both biomass and community composition among sites,
including differences in the abundance of known sulfate-reducing
bacteria. The abundance of sequences for Thermodesulfovibro-like
organisms and higher sulfate reduction rates at elevated temperatures
suggests that Thermodesulfovibro-like organisms may have a role in
sulfate reduction in warmer environments. The rates of sulfate reduction
presented here suggest that-within anaerobic niches of hydrothermal
deposits-heterotrophic sulfate reduction may be quite common and might
contribute substantially to secondary productivity, underscoring the
potential role of this process in both sulfur and carbon cycling at
vents.
BibTeX:
@article{ISI:000320852100014,
  author = {Frank, Kiana L and Rogers, Daniel R and Olins, Heather C and Vidoudez, Charles and Girguis, Peter R},
  title = {Characterizing the distribution and rates of microbial sulfate reduction at Middle Valley hydrothermal vents},
  journal = {ISME JOURNAL},
  year = {2013},
  volume = {7},
  number = {7},
  pages = {1391--1401},
  doi = {10.1038/ismej.2013.17}
}
Lincoln SA, Bradley AS, Newman SA and Summons RE (2013), "Archaeal and bacterial glycerol dialkyl glycerol tetraether lipids in chimneys of the Lost City Hydrothermal Field", ORGANIC GEOCHEMISTRY., jul, 2013. Vol. 60, pp. 45-53.
Abstract: We detected archaeal and bacterial glycerol dialkyl glycerol tetraether
(GDGT) lipids in carbonate chimneys of the Lost City Hydrothermal Field,
an alkaline system near the mid-Atlantic Ridge. Isoprenoidal, archaeal
tetraethers from this site include ``H-shaped'' GDGTs, crenarchaeol and
GDGTs with 0-3 cyclopentane moieties (here referred to as GDGTs 0-3).
Concentrations of GDGT-3 do not track those of GDGTs 0-2 across the
sample set, suggesting that its biosynthesis may be subject to different
controls. Two branched, bacterial GDGTs (brGDGTs) common in terrigenous
environments were also detected. Consulting previously published surveys
of microbial diversity at Lost City and literature on known
precursor-product relationships, we investigated the provenance of these
GDGTs. The principal source of GDGTs 0-3 is likely ANME-1 archaea,
abundant at Lost City. H-shaped GDGTs are likely derived from
thermophilic Methanobacteria and Thermoprotei. Marine Group I
Thaumarchaea detected in Lost City chimneys are a potential source of
crenarchaeol, but it is unclear whether they are autotrophic nitrifiers
or representatives of a hydrothermal ecotype with different physiology.
The detection of branched GDGTs, possibly synthesized by Acidobacteria
at Lost City, adds to a growing body of evidence that the capacity for
their biosynthesis is not restricted to acidophilic soil bacteria and
that they cannot strictly be considered indicators of terrigenous
contributions to marine sediments. Input of hydrothermally derived
lipids has the potential to complicate paleoproxy applications based on
GDGTs. We propose that H-GDGTs be viewed as indicators of hydrothermal
input and that their detection in sediments warrants caution in proxy
application when a hydrothermal origin for co-occurring isoprenoidal and
brGDGTs cannot be excluded. (C) 2013 Elsevier Ltd. All rights reserved.
BibTeX:
@article{ISI:000321109400006,
  author = {Lincoln, Sara A and Bradley, Alexander S and Newman, Sharon A and Summons, Roger E},
  title = {Archaeal and bacterial glycerol dialkyl glycerol tetraether lipids in chimneys of the Lost City Hydrothermal Field},
  journal = {ORGANIC GEOCHEMISTRY},
  year = {2013},
  volume = {60},
  pages = {45--53},
  doi = {10.1016/j.orggeochem.2013.04.010}
}
Mullineaux LS, McGillicuddy Jr. DJ, Mills SW, Kosnyrev VK, Thurnherr AM, Ledwell JR and Lavelle JW (2013), "Active positioning of vent larvae at a mid-ocean ridge", DEEP-SEA RESEARCH PART II-TOPICAL STUDIES IN OCEANOGRAPHY., aug, 2013. Vol. 92(SI), pp. 46-57.
Abstract: The vertical position of larvae of vent species above a mid-ocean ridge
potentially has a strong effect on their dispersal. Larvae may be
advected upward in the buoyant vent plume, or move as a consequence of
their buoyancy or by active swimming. Alternatively, they may be
retained near the bottom by the topography of the axial trough, or by
downward swimming. At vents near 9 degrees 50'N on the axis of the East
Pacific Rise, evidence for active larval positioning was detected in a
comparison between field observations of larvae in the plankton in 2006
and 2007 and distributions of non-swimming larvae in a two-dimensional
bio-physical model. In the field, few vent larvae were collected at the
level of the neutrally buoyant plume (similar to 75 m above the bottom);
their relative abundances at that height were much lower than those of
simulated larvae from a near-bottom release in the model. This
discrepancy was observed for many vent species, particularly gastropods,
suggesting that they may actively remain near the bottom by sinking or
swimming downward. Near the seafloor, larval abundance decreased from
the ridge axis to 1000 m off axis much more strongly in the observations
than in the simulations, again pointing to behavior as a potential
regulator of larval transport. We suspect that transport off axis was
reduced by downward-moving behavior, which positioned larvae into
locations where they were isolated from cross-ridge currents by seafloor
topography, such as the walls of the axial valley which are not resolved
in the model. Cross-ridge gradients in larval abundance varied between
gastropods and polychaetes, indicating that behavior may vary between
taxonomic groups, and possibly between species. These results suggest
that behaviorally mediated retention of vent larvae may be common, even
for species that have a long planktonic larval duration and are capable
of long-distance dispersal. (C) 2013 Elsevier Ltd. All rights reserved.
BibTeX:
@article{ISI:000321177000006,
  author = {Mullineaux, L S and McGillicuddy Jr., D J and Mills, S W and Kosnyrev, V K and Thurnherr, A M and Ledwell, J R and Lavelle, J W},
  title = {Active positioning of vent larvae at a mid-ocean ridge},
  journal = {DEEP-SEA RESEARCH PART II-TOPICAL STUDIES IN OCEANOGRAPHY},
  year = {2013},
  volume = {92},
  number = {SI},
  pages = {46--57},
  doi = {10.1016/j.dsr2.2013.03.032}
}
Sanders JG, Beinart RA, Stewart FJ, Delong EF and Girguis PR (2013), "Metatranscriptomics reveal differences in in situ energy and nitrogen metabolism among hydrothermal vent snail symbionts", ISME JOURNAL., aug, 2013. Vol. 7(8), pp. 1556-1567.
Abstract: Despite the ubiquity of chemoautotrophic symbioses at hydrothermal
vents, our understanding of the influence of environmental chemistry on
symbiont metabolism is limited. Transcriptomic analyses are useful for
linking physiological poise to environmental conditions, but recovering
samples from the deep sea is challenging, as the long recovery times can
change expression profiles before preservation. Here, we present a
novel, in situ RNA sampling and preservation device, which we used to
compare the symbiont metatranscriptomes associated with Alviniconcha, a
genus of vent snail, in which specific host-symbiont combinations are
predictably distributed across a regional geochemical gradient.
Metatranscriptomes of these symbionts reveal key differences in energy
and nitrogen metabolism relating to both environmental chemistry (that
is, the relative expression of genes) and symbiont phylogeny (that is,
the specific pathways employed). Unexpectedly, dramatic differences in
expression of transposases and flagellar genes suggest that different
symbiont types may also have distinct life histories. These data further
our understanding of these symbionts' metabolic capabilities and their
expression in situ, and suggest an important role for symbionts in
mediating their hosts' interaction with regional-scale differences in
geochemistry.
BibTeX:
@article{ISI:000322119600009,
  author = {Sanders, J G and Beinart, R A and Stewart, F J and Delong, E F and Girguis, P R},
  title = {Metatranscriptomics reveal differences in in situ energy and nitrogen metabolism among hydrothermal vent snail symbionts},
  journal = {ISME JOURNAL},
  year = {2013},
  volume = {7},
  number = {8},
  pages = {1556--1567},
  doi = {10.1038/ismej.2013.45}
}
Quattrini AM, Georgian SE, Byrnes L, Stevens A, Falco R and Cordes EE (2013), "Niche divergence by deep-sea octocorals in the genus Callogorgia across the continental slope of the Gulf of Mexico", MOLECULAR ECOLOGY., aug, 2013. Vol. 22(15), pp. 4123-4140.
Abstract: Environmental variables that are correlated with depth have been
suggested to be among the major forces underlying speciation in the deep
sea. This study incorporated phylogenetics and ecological niche models
(ENM) to examine whether congeneric species of Callogorgia
(Octocorallia: Primnoidae) occupy different ecological niches across the
continental slope of the Gulf of Mexico (GoM) and whether this niche
divergence could be important in the evolution of these closely related
species. Callogorgia americana americana, Callogorgia americana delta
and Callogorgia gracilis were documented at 13 sites in the GoM
(250-1000 m) from specimen collections and extensive video observations.
On a first order, these species were separated by depth, with C.
gracilis occurring at the shallowest sites, C. a. americana at
mid-depths and C. a. delta at the deepest sites. Callogorgia a. delta
was associated with areas of increased seep activity, whereas C.
gracilis and C. a. americana were associated with narrow, yet warmer,
temperature ranges and did not occur near cold seeps. ENM background and
identity tests revealed little to no overlap in ecological niches
between species. Temporal calibration of the phylogeny revealed the
formation of the Isthmus of Panama was a vicariance event that may
explain some of the patterns of speciation within this genus. These
results elucidate the potential mechanisms for speciation in the deep
sea, emphasizing both bathymetric speciation and vicariance events in
the evolution of a genus across multiple regions.
BibTeX:
@article{ISI:000322229800020,
  author = {Quattrini, Andrea M and Georgian, Samuel E and Byrnes, Luke and Stevens, Alex and Falco, Rosalia and Cordes, Erik E},
  title = {Niche divergence by deep-sea octocorals in the genus Callogorgia across the continental slope of the Gulf of Mexico},
  journal = {MOLECULAR ECOLOGY},
  year = {2013},
  volume = {22},
  number = {15},
  pages = {4123--4140},
  doi = {10.1111/mec.12370}
}
Eichinger I, Hourdez S and Bright M (2013), "Morphology, microanatomy and sequence data of Sclerolinum contortum (Siboglindae, Annelida) of the Gulf of Mexico", ORGANISMS DIVERSITY & EVOLUTION., sep, 2013. Vol. 13(3), pp. 311-329.
Abstract: Sclerolinum is a small genus of Siboglinidae (Annelida) living in an
obligate mutualistic association with thiotrophic bacteria as adults.
Its taxonomic position, based on morphology, has been controversial;
however, molecular data point to a sister taxa relationship with
vestimentiferans. 16S rRNA gene sequencing and comparative morphology
revealed that the studied population from deep-sea hydrocarbon seeps of
the Gulf of Mexico belongs to Sclerolinum contortum known from the
Arctic Sea. Since no anatomical and microanatomical studies have been
published yet, we conducted such a study on S. contortum using serial
sectioning and light and transmission electron microscopy. We show that
the Sclerolinum body, divided into a head, trunk, and opisthosoma, is
very similar to that of the vestimentiferans, and therefore we propose
that the body regions are homologous in both taxa.
BibTeX:
@article{ISI:000323108100003,
  author = {Eichinger, Irmgard and Hourdez, Stephane and Bright, Monika},
  title = {Morphology, microanatomy and sequence data of Sclerolinum contortum (Siboglindae, Annelida) of the Gulf of Mexico},
  journal = {ORGANISMS DIVERSITY & EVOLUTION},
  year = {2013},
  volume = {13},
  number = {3},
  pages = {311--329},
  doi = {10.1007/s13127-012-0121-3}
}
Ito G, Garcia MO, Smith JR, Taylor B, Flinders A, Jicha B, Yamasaki S, Weis D, Swinnard L and Blay C (2013), "A low-relief shield volcano origin for the South Kaua''i Swell", GEOCHEMISTRY GEOPHYSICS GEOSYSTEMS., jul, 2013. Vol. 14(7), pp. 2328-2348.
Abstract: The South Kauai Swell (SKS) is a 110 km x 80 km ovoid bathymetric
feature that stands textgreater2 km high and abuts the southern flank of the
island of Kauai. The origin of the SKS was investigated using multibeam
bathymetry and acoustic backscatter, gravity data, radiometric ages, and
geochemistry of rock samples. Most of the SKS rock samples are
tholeiitic in composition with ages of 3.9-5.4 Ma indicating they were
derived from shield volcanism. The ages and compositions of the SKS
rocks partially overlap with those of the nearby Niihau, Kauai and West
Kaena volcano complexes. The SKS was originally described as a
landslide; however, this interpretation is problematic given the ovoid
shape of SKS, its relatively smooth, flat-to-convex surface, and the
lack of an obvious source region that could accommodate what would be
one of Earth's most voluminous (6 x 10(3) km(3)) landslides. The
morphology, size, and the surrounding gravity anomaly are more
consistent with the SKS being a low-relief shield volcano, which was
partially covered with a small volume of landside debris from south
Kauai and later with some secondary volcanic seamounts. A shield origin
would imply that Hawaiian and possibly other hotspot shield volcanoes
can take on a wider variety of forms than is commonly thought, ranging
from tall island-building shields, to smaller edifices such as Kaena
Ridge and Mahukona, to even lower-relief volcanoes represented by the
SKS and possibly the South West Oahu Volcanic Field.
BibTeX:
@article{ISI:000323828800015,
  author = {Ito, Garrett and Garcia, Michael O and Smith, John R and Taylor, Brian and Flinders, Ashton and Jicha, Brian and Yamasaki, Seiko and Weis, Dominique and Swinnard, Lisa and Blay, Chuck},
  title = {A low-relief shield volcano origin for the South Kaua''i Swell},
  journal = {GEOCHEMISTRY GEOPHYSICS GEOSYSTEMS},
  year = {2013},
  volume = {14},
  number = {7},
  pages = {2328--2348},
  doi = {10.1002/ggge.20159}
}
Coyne KJ, Countway PD, Pilditch CA, Lee CK, Caron DA and Cary SC (2013), "Diversity and Distributional Patterns of Ciliates in Guaymas Basin Hydrothermal Vent Sediments", JOURNAL OF EUKARYOTIC MICROBIOLOGY., sep, 2013. Vol. 60(5), pp. 433-447.
Abstract: Little is known about protists at deep-sea hydrothermal vents. The vent
sites at Guaymas Basin in the Gulf of California are characterized by
dense mats of filamentous pigmented or nonpigmented Beggiatoa that serve
as markers of subsurface thermochemical gradients. We constructed 18S
rRNA libraries to investigate ciliate assemblages in Beggiatoa mats and
from bare sediments at the Guaymas vent site. Results indicated a high
diversity of ciliates, with 156 operational taxonomic units identified
in 548 sequences. Comparison between mat environments demonstrated that
ciliate and bacterial assemblages from pigmented mats, nonpigmented
mats, and bare sediments were significantly different and highly
correlated with bacterial assemblages. Neither bacterial nor ciliate
assemblages were correlated with environmental factors. The most
abundant ciliates at Guaymas were more likely to be represented in clone
libraries from other hydrothermal, deep-sea, and/or anoxic or
microaerophilic environments, supporting the hypothesis that these
ciliate species are broadly distributed. The orange mat environment
included a higher proportion of ciliate sequences that were more similar
to those from other environmental studies than to cultured ciliate
species, whereas clone libraries from bare sediments included sequences
that were the most highly divergent from all other sequences and may
represent species that are endemic to Guaymas.
BibTeX:
@article{ISI:000324094600001,
  author = {Coyne, Kathryn J and Countway, Peter D and Pilditch, Conrad A and Lee, Charles K and Caron, David A and Cary, Stephen C},
  title = {Diversity and Distributional Patterns of Ciliates in Guaymas Basin Hydrothermal Vent Sediments},
  journal = {JOURNAL OF EUKARYOTIC MICROBIOLOGY},
  year = {2013},
  volume = {60},
  number = {5},
  pages = {433--447},
  doi = {10.1111/jeu.12051}
}
Himmler T, Haley BA, Torres ME, Klinkhammer GP, Bohrmann G and Peckmann J (2013), "Rare earth element geochemistry in cold-seep pore waters of Hydrate Ridge, northeast Pacific Ocean", GEO-MARINE LETTERS., oct, 2013. Vol. 33(5), pp. 369-379.
Abstract: The concentrations of rare earth elements (REEs), sulphate, hydrogen
sulphide, total alkalinity, calcium, magnesium and phosphate were
measured in shallow (textless 12 cm below seafloor) pore waters from cold-seep
sediments on the northern and southern summits of Hydrate Ridge,
offshore Oregon. Downward-decreasing sulphate and coevally increasing
sulphide concentrations reveal sulphate reduction as dominant early
diagenetic process from similar to 2 cm depth downwards. A strong
increase of total dissolved REE (aREE) concentrations is evident
immediately below the sediment-water interface, which can be related to
early diagenetic release of REEs into pore water resulting from the
re-mineralization of particulate organic matter. The highest pore water
aREE concentrations were measured close to the sediment-water interface
at similar to 2 cm depth. Distinct shale-normalized REE patterns point
to particulate organic matter and iron oxides as main REE sources in the
upper similar to 2-cm depth interval. In general, the pore waters have
shale-normalized patterns reflecting heavy REE (HREE) enrichment, which
suggests preferential complexation of HREEs with carbonate ions. Below
similar to 2 cm depth, a downward decrease in aREE correlates with a
decrease in pore water calcium concentrations. At this depth, the
anaerobic oxidation of methane (AOM) coupled to sulphate reduction
increases carbonate alkalinity through the production of bicarbonate,
which results in the precipitation of carbonate minerals. It seems
therefore likely that the REEs and calcium are consumed during vast
AOM-induced precipitation of carbonate in shallow Hydrate Ridge
sediments. The analysis of pore waters from Hydrate Ridge shed new light
on early diagenetic processes at cold seeps, corroborating the great
potential of REEs to identify geochemical processes and to constrain
environmental conditions.
BibTeX:
@article{ISI:000324619100004,
  author = {Himmler, Tobias and Haley, Brian A and Torres, Marta E and Klinkhammer, Gary P and Bohrmann, Gerhard and Peckmann, Joern},
  title = {Rare earth element geochemistry in cold-seep pore waters of Hydrate Ridge, northeast Pacific Ocean},
  journal = {GEO-MARINE LETTERS},
  year = {2013},
  volume = {33},
  number = {5},
  pages = {369--379},
  doi = {10.1007/s00367-013-0334-2}
}
Eecke HCV, Akerman NH, Huber JA, Butterfield DA and Holden JF (2013), "Growth kinetics and energetics of a deep-sea hyperthermophilic methanogen under varying environmental conditions", ENVIRONMENTAL MICROBIOLOGY REPORTS., oct, 2013. Vol. 5(5), pp. 665-671.
Abstract: A hyperthermophilic deep-sea methanogen, Methanocaldococcus strain
JH146, was isolated from 26 degrees C hydrothermal fluid at Axial
Volcano to model high temperature methanogenesis in the subseafloor.
Emphasis was placed on defining growth kinetics, cell yields and growth
energy demand (GE) across a range of conditions. The organism uses H-2
and CO2 as its sole carbon and energy sources. At various temperatures,
pHs, and chlorinities, its growth rates and cell yields co-varied while
GE remained uniform at 1.69x10(-11) J cell(-1)s(-1)+/- 0.68x10(-11) J
cell(-1)s(-1) (s.d., n=23). An exception was at superoptimal growth
temperatures where GE increased to 7.25x10(-11) J cell(-1)s(-1)
presumably due to heat shock. GE also increased from 5.1x10(-12) J
cell(-1)s(-1) to 7.61x10(-11) J cell(-1)s(-1) as NH4+ concentrations
decreased from 9.4mM to 0.14mM. JH146 did not fix N-2 or assimilate
NO3-, lacked the N-2-fixing (cluster II) nifH gene, and became nitrogen
limited below 0.14mM NH4Cl. Nitrogen availability may impact growth in
situ since ammonia concentrations at Axial Volcano are textless18M. Our
approach contributes to refining bioenergetic and carbon flux models for
methanogens and other organisms in hydrothermal vents and other
environments.
BibTeX:
@article{ISI:000325142700005,
  author = {Eecke, Helene C Ver and Akerman, Nancy H and Huber, Julie A and Butterfield, David A and Holden, James F},
  title = {Growth kinetics and energetics of a deep-sea hyperthermophilic methanogen under varying environmental conditions},
  journal = {ENVIRONMENTAL MICROBIOLOGY REPORTS},
  year = {2013},
  volume = {5},
  number = {5},
  pages = {665--671},
  doi = {10.1111/1758-2229.12065}
}
Perez-Rodriguez I, Bohnert KA, Cuebas M, Keddis R and Vetriani C (2013), "Detection and phylogenetic analysis of the membrane-bound nitrate reductase (Nar) in pure cultures and microbial communities from deep-sea hydrothermal vents", FEMS MICROBIOLOGY ECOLOGY., nov, 2013. Vol. 86(2), pp. 256-267.
Abstract: Over the past few years the relevance of nitrate respiration in
microorganisms from deep-sea hydrothermal vents has become evident. In
this study, we surveyed the membrane-bound nitrate reductase (Nar)
encoding gene in three different deep-sea vent microbial communities
from the East Pacific Rise and the Mid-Atlantic Ridge. Additionally, we
tested pure cultures of vent strains for their ability to reduce nitrate
and for the presence of the NarG-encoding gene in their genomes. By
using the narG gene as a diagnostic marker for nitrate-reducing
bacteria, we showed that nitrate reductases related to
Gammaproteobacteria of the genus Marinobacter were numerically prevalent
in the clone libraries derived from a black smoker and a diffuse flow
vent. In contrast, NarG sequences retrieved from a community of
filamentous bacteria located about 50cm above a diffuse flow vent
revealed the presence of a yet to be identified group of enzymes. 16S
rRNA gene-inferred community compositions, in accordance with previous
studies, showed a shift from Alpha- and Gammaproteobacteria to
Epsilonproteobacteria as the vent fluids become warmer and more
reducing. Based on these findings, we argue that Nar-catalyzed nitrate
reduction is likely relevant in temperate and less reducing environments
where Alpha- and Gammaproteobacteria are more abundant and where nitrate
concentrations reflect that of background deep seawater.
BibTeX:
@article{ISI:000325986500008,
  author = {Perez-Rodriguez, Ileana and Bohnert, Kenneth A and Cuebas, Mariola and Keddis, Ramaydalis and Vetriani, Costantino},
  title = {Detection and phylogenetic analysis of the membrane-bound nitrate reductase (Nar) in pure cultures and microbial communities from deep-sea hydrothermal vents},
  journal = {FEMS MICROBIOLOGY ECOLOGY},
  year = {2013},
  volume = {86},
  number = {2},
  pages = {256--267},
  doi = {10.1111/1574-6941.12158}
}
McClinton T, White SM, Colman A and Sinton JM (2013), "Reconstructing lava flow emplacement processes at the hot spot-affected Galapagos Spreading Center, 95 degrees W and 92 degrees W", GEOCHEMISTRY GEOPHYSICS GEOSYSTEMS., aug, 2013. Vol. 14(8), pp. 2731-2756.
Abstract: Volcanic eruptions at mid-ocean ridges (MORs) control the permeability,
internal structure, and architecture of oceanic crust, thus establishing
the foundation for the evolution of the ocean basins. To better
understand the emplacement of submarine lava flows at MORs, we have
integrated submersible-based geologic mapping with remote sensing
techniques to characterize the lava flow morphology within previously
mapped lava flow fields produced during single eruptive episodes at the
Galapagos Spreading Center (GSC). Detailed attributes describing the
surface geometry and texture of the lava flows have been extracted from
high-resolution sonar data and combined with georeferenced visual
observations from submersible dives and camera tows; based on signatures
contained in these data, a fuzzy logic-based classification algorithm
categorized lava flow morphology as pillows, lobates, or sheets. The
resulting digital thematic maps offer an unprecedented view of GSC lava
morphology, collectively covering 77 km(2) of ridge axis terrain at a
resolution of 2 m x 2 m. Error assessments with independent visual
reference data indicate approximately 90% agreement, comparable to
subaerial classification studies. The digital lava morphology maps
enable quantitative, spatially comprehensive measurements of the
abundance and distribution of lava morphologies over large areas of
seafloor and within individual eruptive units. A comparison of lava flow
fields mapped at lower- and higher-magma-supply settings (95 degrees and
92 degrees W, respectively) indicates that effusion rates increase along
with magma supply and independent of spreading rate at the GSC, although
a complete range of eruptive behavior exists at each setting.
BibTeX:
@article{ISI:000326242700011,
  author = {McClinton, Tim and White, Scott M and Colman, Alice and Sinton, John M},
  title = {Reconstructing lava flow emplacement processes at the hot spot-affected Galapagos Spreading Center, 95 degrees W and 92 degrees W},
  journal = {GEOCHEMISTRY GEOPHYSICS GEOSYSTEMS},
  year = {2013},
  volume = {14},
  number = {8},
  pages = {2731--2756},
  doi = {10.1002/ggge.20157}
}
Hearn CK, Homola KL and Johnson HP (2013), "Surficial permeability of the axial valley seafloor: Endeavour Segment, Juan de Fuca Ridge", GEOCHEMISTRY GEOPHYSICS GEOSYSTEMS., sep, 2013. Vol. 14(9), pp. 3409-3424.
Abstract: Hydrothermal systems at mid-ocean spreading centers play a fundamental
role in Earth's geothermal budget. One underexamined facet of marine
hydrothermal systems is the role that permeability of the uppermost
seafloor veneer plays in the distribution of hydrothermal fluid. As both
the initial and final vertical gateway for subsurface fluid circulation,
uppermost seafloor permeability may influence the local spatial
distribution of hydrothermal flow. A method of deriving a photomosaic
from seafloor video was developed and utilized to estimate relative
surface permeability in an active hydrothermal area on the Endeavour
Segment of the Juan de Fuca Ridge. The mosaic resolves seafloor geology
of the axial valley seafloor at submeter resolution over an area greater
than 1 km(2). Results indicate that the valley walls and basal talus
slope are topographically rugged and unsedimented, providing minimal
resistance to fluid transmission. Elsewhere, the axial valley floor is
capped by an unbroken blanket of low-permeability sediment, resisting
fluid exchange with the subsurface reservoir. Active fluid emission
sites were restricted to the high-permeability zone at the base of the
western wall. A series of inactive fossil hydrothermal structures form a
linear trend along the western bounding wall, oriented orthogonal to the
spreading axis. High-temperature vent locations appear to have migrated
over 100 m along-ridge-strike over the decade between surveys. While
initially an expression of subsurface faulting, this spatial pattern
suggests that increases in seafloor permeability from sedimentation may
be at least a secondary contributing factor in regulating fluid flow
across the seafloor interface.
BibTeX:
@article{ISI:000326247700007,
  author = {Hearn, Casey K and Homola, Kira L and Johnson, H Paul},
  title = {Surficial permeability of the axial valley seafloor: Endeavour Segment, Juan de Fuca Ridge},
  journal = {GEOCHEMISTRY GEOPHYSICS GEOSYSTEMS},
  year = {2013},
  volume = {14},
  number = {9},
  pages = {3409--3424},
  doi = {10.1002/ggge.20209}
}
Bates AE, Bird TJ, Robert K, Onthank KL, Quinn GP, Juniper SK and Lee RW (2013), "Activity and positioning of eurythermal hydrothermal vent sulphide worms in a variable thermal environment", JOURNAL OF EXPERIMENTAL MARINE BIOLOGY AND ECOLOGY., oct, 2013. Vol. 448, pp. 149-155.
Abstract: Here we investigate behavioral responses to fine-scale spatial and
temporal temperature gradients in a heat tolerant hydrothermal vent worm
(Paralvinella sulfincola). While this species has been a model organism
for understanding physiological adaptations to extreme environments,
lacking are corroborative in situ experiments and characterization of
temperature-related behaviors representing the lower thermal tolerance
range of this species. To address this knowledge gap, we first
quantified the upper thermal limit for this species using a rapid
heating protocol executed remotely on the seafloor. Second, we used a
combination of in situ observations and shipboard experiments to test
for temperature-dependent patterns in activity and behavior. We confirm
that P. sulfincola is remarkably eurythermal and demonstrates a thermal
niche breadth exceeding 45 degrees C. We further show that the activity
and positioning of worms relate to temperatures within its lower
preferred range (i.e., between 4 and 20 degrees C). Worms tended to
remain closer to their tube openings and held their branchial crown in a
consistent location when fluids were relatively warm. By contrast, when
fluids were cooler, both the distance worms were observed from their
tubes and positioning of their branchial crown were more variable. A
Bayesian hidden Markov model classified each worm at each time interval
as being in a high or low activity state according to the magnitude of
change in their orientation and how far they moved between successive
time lapse images. We found that the transition between active and
inactive states at any time period is related to fluid temperature. Our
observations indicate that the behavior of the worms is
temperature-dependent, which may in turn reflect temperature-related
variables such as the delivery of food particles, dissolved oxygen
concentration, or relative environmental variability. Our findings
demonstrate that this species can respond behaviorally to very
fine-scale environmental variability in a manner not simply predicted by
models of increasing activity with temperature. (C) 2013 Elsevier B.V.
All rights reserved.
BibTeX:
@article{ISI:000326430500019,
  author = {Bates, Amanda E and Bird, Tomas J and Robert, Katleen and Onthank, Kirt L and Quinn, Gerry P and Juniper, S Kim and Lee, Raymond W},
  title = {Activity and positioning of eurythermal hydrothermal vent sulphide worms in a variable thermal environment},
  journal = {JOURNAL OF EXPERIMENTAL MARINE BIOLOGY AND ECOLOGY},
  year = {2013},
  volume = {448},
  pages = {149--155},
  doi = {10.1016/j.jembe.2013.06.015}
}
MacGregor BJ, Biddle JF, Harbort C, Matthysse AG and Teske A (2013), "Sulfide oxidation, nitrate respiration, carbon acquisition, and electron transport pathways suggested by the draft genome of a single orange Guaymas Basin Beggiatoa (Cand. Maribeggiatoa) sp filament", MARINE GENOMICS., sep, 2013. Vol. 11, pp. 53-65.
Abstract: A near-complete draft genome has been obtained for a single vacuolated
orange Beggiatoa (Cand. Maribeggiatoa) filament from a Guaymas Basin
seafloor microbial mat, the third relatively complete sequence for the
Beggiatoaceae. Possible pathways for sulfide oxidation; nitrate
respiration; inorganic carbon fixation by both Type II RuBisCO and the
reductive tricarboxylic add cycle; acetate and possibly formate uptake;
and energy-generating electron transport via both oxidative
phosphorylation and the Rnf complex are discussed here. A role in
nitrite reduction is suggested for an abundant orange cytochrome
produced by the Guaymas strain; this has a possible homolog in Beggiatoa
(Cand. Isobeggiatoa) sp. PS, isolated from marine harbor sediment, but
not Beggiatoa alba B18LD, isolated from a freshwater rice field ditch.
Inferred phylogenies for the Calvin-Benson-Bassham (CBB) cycle and the
reductive (rTCA) and oxidative (TCA) tricarboxylic acid cycles suggest
that genes encoding succinate dehydrogenase and enzymes for
carboxylation and/or decarboxylation steps (including RuBisCO) may have
been introduced to (or exported from) one or more of the three genomes
by horizontal transfer, sometimes by different routes. Sequences from
the two marine strains are generally more similar to each other than to
sequences from the freshwater strain, except in the case of RuBisCO:
only the Guaymas strain encodes a Type H enzyme, which (where studied)
discriminates less against oxygen than do Type I RuBisCOs. Genes subject
to horizontal transfer may represent key steps for adaptation to factors
such as oxygen and carbon dioxide concentration, organic carbon
availability, and environmental variability. (C) 2013 Elsevier B.V. All
rights reserved.
BibTeX:
@article{ISI:000326614000008,
  author = {MacGregor, Barbara J and Biddle, Jennifer F and Harbort, Christopher and Matthysse, Ann G and Teske, Andreas},
  title = {Sulfide oxidation, nitrate respiration, carbon acquisition, and electron transport pathways suggested by the draft genome of a single orange Guaymas Basin Beggiatoa (Cand. Maribeggiatoa) sp filament},
  journal = {MARINE GENOMICS},
  year = {2013},
  volume = {11},
  pages = {53--65},
  doi = {10.1016/j.margen2013.08.001}
}
Sylvan JB, Sia TY, Haddad AG, Briscoe LJ, Toner BM, Girguis PR and Edwards KJ (2013), "Low temperature geomicrobiology follows host rock composition along a geochemical gradient in Lau Basin", FRONTIERS IN MICROBIOLOGY., mar, 2013. Vol. 4
Abstract: The East Lau Spreading Center (ELSC) and Valu Fa Ridge (VFR) comprise a
ridge segment in the southwest Pacific Ocean where rapid transitions in
the underlying mantle chemistry manifest themselves as gradients in
seafloor rock geochemistry. We studied the geology and microbial
diversity of three silicate rock samples and three inactive sulfide
chimney samples collected, from north to south, at the vent fields Kilo
Moana, ABE, Tui Malila, and Mariner. This is the first study of
microbial populations on basaltic andesite, which was sampled at Mariner
vent field. Silicate rock geochemistry exhibits clear latitudinal trends
that are mirrored by changes in bacterial community composition.
alpha-proteobacteria, epsilon-proteobacteria, and Bacteroidetes are most
common on a silicate collected from Kilo Moana and their proportions
decrease linearly on silicates collected further south. Conversely, a
silicate from Mariner vent field hosts high proportions of a unique
lineage of Chloroflexi unrelated (textless90% sequence similarity) to
previously recovered environmental clones or isolates, which decrease at
ABE and are absent at Kilo Moana. The exteriors of inactive sulfide
structures are dominated by lineages of sulfur oxidizing
alpha-proteobacteria, gamma-proteobacteria, and epsilon-proteobacteria,
while the interior of one chimney is dominated by putative
sulfur-reducing delta-proteobacteria. A comparison of bacterial
communities on inactive sulfides from this and previous studies reveals
the presence of a clade of uncultured Bacteroidetes exclusive to
sulfidic environments, and a high degree of heterogeneity in bacterial
community composition from one sulfide structure to another. In light of
the heterogeneous nature of bacterial communities observed here and in
previous studies of both active and inactive hydrothermal sulfide
structures, the presence of numerous niches may be detected on these
structures in the future by finer scale sampling and analysis.
BibTeX:
@article{ISI:000331005900001,
  author = {Sylvan, Jason B and Sia, Tiffany Y and Haddad, Amanda G and Briscoe, Lindsey J and Toner, Brandy M and Girguis, Peter R and Edwards, Katrina J},
  title = {Low temperature geomicrobiology follows host rock composition along a geochemical gradient in Lau Basin},
  journal = {FRONTIERS IN MICROBIOLOGY},
  year = {2013},
  volume = {4},
  doi = {10.3389/fmicb.2013.00061}
}
Adams MM, Hoarfrost AL, Bose A, Joye SB and Girguis PR (2013), "Anaerobic oxidation of short-chain alkanes in hydrothermal sediments: potential influences on sulfur cycling and microbial diversity", FRONTIERS IN MICROBIOLOGY., may, 2013. Vol. 4
Abstract: Short-chain alkanes play a substantial role in carbon and sulfur cycling
at hydrocarbon-rich environments globally, yet few studies have examined
the metabolism of ethane (C-2), propane (C-3), and butane (C-4) in
anoxic sediments in contrast to methane (C-1). In hydrothermal vent
systems, short-chain alkanes are formed over relatively short geological
time scales via thermogenic processes and often exist at high
concentrations. The sediment-covered hydrothermal vent systems at Middle
Valley (MV Juan de Fuca Ridge) are an ideal site for investigating the
anaerobic oxidation of C-1-C-4 alkanes, given the elevated temperatures
and dissolved hydrocarbon species characteristic of these metalliferous
sediments. We examined whether MV microbial communities oxidized C-1-C-4
alkanes under mesophilic to thermophilic sulfate-reducing conditions.
Here we present data from discrete temperature (25, 55, and 75 degrees
C) anaerobic batch reactor incubations of MV sediments supplemented with
individual alkanes. Co-registered alkane consumption and sulfate
reduction (SR) measurements provide clear evidence for C-1-C-4 alkane
oxidation linked to SR over time and across temperatures. In these
anaerobic batch reactor sediments, 16S ribosomal RNA pyrosequencing
revealed that Deltaproteobacteria, particularly a novel sulfate-reducing
lineage, were the likely phylotypes mediating the oxidation of C-2-C-4
alkanes. Maximum C-1-C-4 alkane oxidation rates occurred at 55 degrees
C, which reflects the mid-core sediment temperature profile and
corroborates previous studies of rate maxima for the anaerobic oxidation
of methane (AOM). Of the alkanes investigated, C-3 was oxidized at the
highest rate over time, then C-4, C-2, and C-1, respectively. The
implications of these results are discussed with respect to the
potential competition between the anaerobic oxidation of C-2-C(4)alkanes
with AOM for available oxidants and the influence on the fate of C-1
derived from these hydrothermal systems.
BibTeX:
@article{ISI:000331111400001,
  author = {Adams, Melissa M and Hoarfrost, Adrienne L and Bose, Arpita and Joye, Samantha B and Girguis, Peter R},
  title = {Anaerobic oxidation of short-chain alkanes in hydrothermal sediments: potential influences on sulfur cycling and microbial diversity},
  journal = {FRONTIERS IN MICROBIOLOGY},
  year = {2013},
  volume = {4},
  doi = {10.3389/fmicb.2013.00110}
}
He Y, Xiao X and Wang F (2013), "Metagenome reveals potential microbial degradation of hydrocarbon coupled with sulfate reduction in an oil-immersed chimney from Guaymas Basin", FRONTIERS IN MICROBIOLOGY., jun, 2013. Vol. 4
Abstract: Deep-sea hydrothermal vent chimneys contain a high diversity of
microorganisms, yet the metabolic activity and the ecological functions
of the microbial communities remain largely unexplored. In this study, a
metagenomic approach was applied to characterize the metabolic potential
in a Guaymas hydrothermal vent chimney and to conduct comparative
genomic analysis among a variety of environments with sequenced
metagenomes. Complete clustering of functional gene categories with a
comparative metagenomic approach showed that this Guaymas chimney
metagenome was clustered most closely with a chimney metagenome from
Juan de Fuca. All chimney samples were enriched with genes involved in
recombination and repair, chemotaxis and flagellar assembly,
highlighting their roles in coping with the fluctuating extreme deep-sea
environments. A high proportion of transposases was observed in all the
metagenomes from deep-sea chimneys, supporting the previous hypothesis
that horizontal gene transfer may be common in the deep-sea vent chimney
biosphere. In the Guaymas chimney metagenome, thermophilic sulfate
reducing microorganisms including bacteria and archaea were found
predominant, and genes coding for the degradation of refractory organic
compounds such as cellulose, lipid, pullullan, as well as a few
hydrocarbons including toluene, ethylbenzene and o-xylene were
identified. Therefore, this oil-immersed chimney supported a
thermophilic microbial community capable of oxidizing a range of
hydrocarbons that served as electron donors for sulphate reduction under
anaerobic conditions.
BibTeX:
@article{ISI:000331170400001,
  author = {He, Ying and Xiao, Xiang and Wang, Fengping},
  title = {Metagenome reveals potential microbial degradation of hydrocarbon coupled with sulfate reduction in an oil-immersed chimney from Guaymas Basin},
  journal = {FRONTIERS IN MICROBIOLOGY},
  year = {2013},
  volume = {4},
  doi = {10.3389/fmicb.2013.00148}
}
Akerman NH, Butterfield DA and Huber JA (2013), "Phylogenetic diversity and functional gene patterns of sulfur-oxidizing subseafloor Epsilonproteobacteria in diffuse hydrothermal vent fluids", FRONTIERS IN MICROBIOLOGY., jul, 2013. Vol. 4
Abstract: Microorganisms throughout the dark ocean use reduced sulfur compounds
for chemolithoautotrophy. In many deep-sea hydrothermal vents, sulfide
oxidation is quantitatively the most important chemical energy source
for microbial metabolism both at and beneath the seafloor. In this
study, the presence and activity of vent endemic Epsilonproteobacteria
was examined in six low-temperature diffuse vents over a range of
geochemical gradients from Axial Seamount, a deep-sea volcano in the
Northeast Pacific. PCR primers were developed and applied to target the
sulfur oxidation soxB gene of Epsilonproteobacteria. soxB genes
belonging to the genera Sulfurimonas and Sulfurovum are both present and
expressed at most diffuse vent sites, but not in background seawater.
Although Sulfurovum-like sox8 genes were detected in all fluid samples,
the RNA profiles were nearly identical among the vents and suggest that
Sulfurirnonas-like species are the primary Epsilonproteobacteria
responsible for actively oxidizing sulfur via the Sox pathway at each
vent. Community patterns of subseafloor Epsdonproteobactena 16S rRNA
genes were best matched to methane concentrations in vent fluids, as
well as individual vent locations, indicating that both geochemistry and
geographical isolation play a role in structuring subseafloor microbial
populations. The data show that in the subseafloor at Axial Seamount,
Epsilonproteobacteria are expressing the soxB gene and that microbial
patterns in community distribution are linked to both vent location and
chemistry.
BibTeX:
@article{ISI:000331246100002,
  author = {Akerman, Nancy H and Butterfield, David A and Huber, Julie A},
  title = {Phylogenetic diversity and functional gene patterns of sulfur-oxidizing subseafloor Epsilonproteobacteria in diffuse hydrothermal vent fluids},
  journal = {FRONTIERS IN MICROBIOLOGY},
  year = {2013},
  volume = {4},
  doi = {10.3389/fmicb.2013.00185}
}
Campbell BJ, Polson SW, Allen LZ, Williamson SJ, Lee CK, Wommack KE and Cary SC (2013), "Diffuse flow environments within basalt- and sediment-based hydrothermal vent ecosystems harbor specialized microbial communities", FRONTIERS IN MICROBIOLOGY., jul, 2013. Vol. 4
Abstract: Hydrothermal vents differ both in surface input and subsurface
geochemistry. The effects of these differences on their microbial
communities are not clear. Here, we investigated both alpha and beta
diversity of diffuse flow-associated microbial communities emanating
from vents at a basalt-based hydrothermal system along the East Pacific
Rise (EPR) and a sediment-based hydrothermal system, Guaymas Basin. Both
Bacteria and Archaea were targeted using high throughput 16S rRNA gene
pyrosequencing analyses. A unique aspect of this study was the use of a
universal set of 16S rRNA gene primers to characterize total and diffuse
flow-specific microbial communities from varied deep-sea hydrothermal
environments. Both surrounding seawater and diffuse flow water samples
contained large numbers of Marine Group I (MGI) Thaumarchaea and
Gammaproteobacteria taxa previously observed in deep-sea systems.
However, these taxa were geographically distinct and segregated
according to type of spreading center. Diffuse flow microbial community
profiles were highly differentiated. In particular, EPR dominant diffuse
flow taxa were most closely associated with chemolithoautotrophs, and
off axis water was dominated by heterotrophic-related taxa, whereas the
opposite was true for Guaymas Basin. The diversity and richness of
diffuse flow-specific microbial communities were strongly correlated to
the relative abundance of Epsilonproteobacteria, proximity to
macrofauna, and hydrothermal system type. Archaeal diversity was higher
than or equivalent to bacterial diversity in about one third of the
samples. Most diffuse flow-specific communities were dominated by OTUs
associated with Epsilonproteobacteria, but many of the Guaymas Basin
diffuse flow samples were dominated by either OTUs within the
Planctomycetes or hyperthermophilic Archaea. This study emphasizes the
unique microbial communities associated with geochemically and
geographically distinct hydrothermal diffuse flow environments.
BibTeX:
@article{ISI:000331366100001,
  author = {Campbell, Barbara J and Polson, Shawn W and Allen, Lisa Zeigler and Williamson, Shannon J and Lee, Charles K and Wommack, K Eric and Cary, S Craig},
  title = {Diffuse flow environments within basalt- and sediment-based hydrothermal vent ecosystems harbor specialized microbial communities},
  journal = {FRONTIERS IN MICROBIOLOGY},
  year = {2013},
  volume = {4},
  doi = {10.3389/fmicb.2013.00182}
}
Meyer S, Wegener G, Lloyd KG, Teske A, Boetius A and Ramette A (2013), "Microbial habitat connec ivity across spatial scales and hydrothermal temperature gradients at Guaymas Basin", FRONTIERS IN MICROBIOLOGY., jul, 2013. Vol. 4
Abstract: The Guaymas Basin (Gulf of California) hydrothermal vent area is known
as a dynamic and hydrothermally vented sedimentary system, where the
advection and production of a variety of different metabolic substrates
support a high microbial diversity and activity in the seafloor. The
main objective of our study was to explore the role of temperature and
other environmental factors on community diversity, such as the presence
of microbial mats and seafloor bathymetry within one hydrothermally
vented field of 200 x 250 m dimension. In this field, temperature
increased strongly with sediment depth reaching the known limit of life
within a few decimeters. Potential sulfate reduction rate as a key
community activity parameter was strongly affected by in situ
temperature and sediment depth, declining from high rates of 1-5 jimol
m1-1 d-1 at the surface to the detection limit below 5 cm sediment
depth, despite the presence of sulfate and hydrocarbons. Automated
Ribosomal lntergenic Spacer Analysis yielded a high-resolution
fingerprint of the dominant members of the bacterial community. Our
analyses showed strong temperature and sediment depth effects on
bacterial cell abundance and Operational Taxonomic Units (OTUs) number,
both declining by more than one order of magnitude below the top 5 cm of
the sediment surface. Another fraction of the variation in diversity and
community structure was explained by differences in the local bathymetry
and spatial position within the vent field. Nevertheless, more than 80%
of all detected OTUs were shared among the different temperature realms
and sediment depths, after being classified as cold (T textless 10 C), medium
(10 C textless T textless 40 C) or hot (T textgreater 40 C) temperature conditions, with
significant OTU overlap with the richer surface communities. Overall,
this indicates a high connectivity of benthic bacterial habitats in this
dynamic and heterogeneous marine ecosystem influenced by strong
hydrothermalism.
BibTeX:
@article{ISI:000331366700001,
  author = {Meyer, Stefanie and Wegener, Gunter and Lloyd, Karen G and Teske, Andreas and Boetius, Antje and Ramette, Alban},
  title = {Microbial habitat connec ivity across spatial scales and hydrothermal temperature gradients at Guaymas Basin},
  journal = {FRONTIERS IN MICROBIOLOGY},
  year = {2013},
  volume = {4},
  doi = {10.3389/fmicb.2013.00207}
}
Bose A, Rogers DR, Adams MM, Joye SB and Girguis PR (2013), "Geomicrobiological linkages between short-chain alkane consumption and sulfate reduction rates in seep sediments", FRONTIERS IN MICROBIOLOGY., dec, 2013. Vol. 4
Abstract: Marine hydrocarbon seeps are ecosystems that are rich in methane, and,
in some cases, short-chain (C-2-C-5) and longer alkanes. C-2-C-4 alkanes
such as ethane, propane, and butane can be significant components of
seeping fluids. Some sulfate-reducing microbes oxidize short-chain
alkanes anaerobically, and may play an important role in both the
competition for sulfate and the local carbon budget. To better
understand the anaerobic oxidation of short-chain n-alkanes coupled with
sulfate-reduction, hydrocarbon-rich sediments from the Gulf of Mexico
(GoM) were amended with artificial, sulfate-replete seawater and one of
four n-alkanes (C-1-C-4) then incubated under strict anaerobic
conditions. Measured rates of alkane oxidation and sulfate reduction
closely follow stoichiometric predictions that assume the complete
oxidation of alkanes to CO2 (though other sinks for alkane carbon likely
exist). Changes in the delta C-13 of all the alkanes in the reactors
show enrichment over the course of the incubation, with the C-3 and C-4
incubations showing the greatest enrichment (4.4 and 4.5 parts per
thousand, respectively). The concurrent depletion in the delta C-13 of
dissolved inorganic carbon (DIC) implies a transfer of carbon from the
alkane to the DIC pool (-3.5 and -6.7 parts per thousand for C-3 and C-4
incubations, respectively). Microbial community analyses reveal that
certain members of the class Deltaproteobacteria are selectively
enriched as the incubations degrade C-1-C-4 alkanes. Phylogenetic
analyses indicate that distinct phylotypes are enriched in the ethane
reactors, while phylotypes in the propane and butane reactors align with
previously identified C-3-C-4 alkane-oxidizing sulfate-reducers. These
data further constrain the potential influence of alkane oxidation on
sulfate reduction rates (SRRs) in cold hydrocarbon-rich sediments,
provide insight into their contribution to local carbon cycling, and
illustrate the extent to which short-chain alkanes can serve as electron
donors and govern microbial community composition and density.
BibTeX:
@article{ISI:000331550900001,
  author = {Bose, Arpita and Rogers, Daniel R and Adams, Melissa M and Joye, Samantha B and Girguis, Peter R},
  title = {Geomicrobiological linkages between short-chain alkane consumption and sulfate reduction rates in seep sediments},
  journal = {FRONTIERS IN MICROBIOLOGY},
  year = {2013},
  volume = {4},
  doi = {10.3389/fmicb.2013.00386}
}
Jacobson A, Plouviez S, Thaler AD and Van Dover CL (2013), "Characterization of 9 polymorphic microsatellite loci in Lamellibrachia sp 2, a tubeworm found at deep-sea hydrothermal vents and cold seeps", Conservation Genetics Resources., dec, 2013. Vol. 5(4), pp. 1005-1007.
Abstract: Lamellibrachia sp. 2 is a deep-sea vestimentiferan tubeworm found at hydrothermal vents on the Mid-Cayman Spreading Center and at hydrocarbon seeps in the Gulf of Mexico and off the coast of Barbados. Nine selectively neutral and unlinked polymorphic microsatellite loci were developed for this species. Eight of these loci conformed to Hardy-Weinberg expectations. Average observed heterozygosity ranged from 0.14 to 0.92. Microsatellites developed for Lamellibrachia sp. 2 are being deployed to study connectivity and gene flow among populations of this species.
BibTeX:
@article{Jacobson2013,
  author = {Jacobson, A and Plouviez, S and Thaler, A D and Van Dover, C L},
  title = {Characterization of 9 polymorphic microsatellite loci in Lamellibrachia sp 2, a tubeworm found at deep-sea hydrothermal vents and cold seeps},
  journal = {Conservation Genetics Resources},
  year = {2013},
  volume = {5},
  number = {4},
  pages = {1005--1007},
  doi = {10.1007/s12686-013-9955-z}
}
Jacobson A, Plouviez S, Thaler AD and Van Dover CL (2013), "Characterization of 13 polymorphic microsatellite loci in Rimicaris hybisae, a shrimp from deep-sea hydrothermal vents", Conservation Genetics Resources., jun, 2013. Vol. 5(2), pp. 449-451.
Abstract: Rimicaris hybisae is a deep-sea alvinocaridid shrimp found at hydrothermal vents along the Mid-Cayman Spreading Center. Eleven selectively neutral and unlinked polymorphic microsatellite loci were developed for this species and two additional loci were found to cross-amplify from a related species. Nine loci conformed to Hardy-Weinberg expectations. Seven loci cross-amplified with Chorocaris sp. 2, an alvinocaridid shrimp found at vents in the Southwestern Pacific. Microsatellite loci developed for R. hybisae are being deployed to study connectivity and genetic variability of populations along the Mid-Cayman Spreading Center.
BibTeX:
@article{Jacobson2013a,
  author = {Jacobson, A and Plouviez, S and Thaler, A D and Van Dover, C L},
  title = {Characterization of 13 polymorphic microsatellite loci in Rimicaris hybisae, a shrimp from deep-sea hydrothermal vents},
  journal = {Conservation Genetics Resources},
  year = {2013},
  volume = {5},
  number = {2},
  pages = {449--451},
  doi = {10.1007/s12686-012-9825-0}
}
Jamieson JW, Hannington MD, Clague DA, Kelley DS, Delaney JR, Holden JF, Tivey MK and Kimpe LE (2013), "Sulfide geochronology along the Endeavour Segment of the Juan de Fuca Ridge", Geochemistry, Geophysics, Geosystems. Vol. 14(7), pp. 2084-2099.
Abstract: Forty-nine hydrothermal sulfide-sulfate rock samples from the Endeavour Segment of the Juan de Fuca Ridge, northeastern Pacific Ocean, were dated by measuring the decay of 226Ra (half-life of 1600 years) in hydrothermal barite to provide a history of hydrothermal venting at the site over the past 6000 years. This dating method is effective for samples ranging in age from ∼200 to 20,000 years old and effectively bridges an age gap between shorter- and longer-lived U-series dating techniques for hydrothermal deposits. Results show that hydrothermal venting at the active High Rise, Sasquatch, and Main Endeavour fields began at least 850, 1450, and 2300 years ago, respectively. Barite ages of other inactive deposits on the axial valley floor are between ∼1200 and ∼2200 years old, indicating past widespread hydrothermal venting outside of the currently active vent fields. Samples from the half-graben on the eastern slope of the axial valley range in age from ∼1700 to ∼2925 years, and a single sample from outside the axial valley, near the westernmost valley fault scarp is ∼5850 ± 205 years old. The spatial relationship between hydrothermal venting and normal faulting suggests a temporal relationship, with progressive younging of sulfide deposits from the edges of the axial valley toward the center of the rift. These relationships are consistent with the inward migration of normal faulting toward the center of the valley over time and a minimum age of onset of hydrothermal activity in this region of 5850 years.
BibTeX:
@article{Jamieson2013,
  author = {Jamieson, J W and Hannington, M D and Clague, D A and Kelley, D S and Delaney, J R and Holden, J F and Tivey, M K and Kimpe, L E},
  title = {Sulfide geochronology along the Endeavour Segment of the Juan de Fuca Ridge},
  journal = {Geochemistry, Geophysics, Geosystems},
  year = {2013},
  volume = {14},
  number = {7},
  pages = {2084--2099},
  doi = {10.1002/ggge.20133}
}
Joseph C, Campbell KA, Torres ME, Martin RA, Pohlman JW, Riedel M and Rose K (2013), "Methane-derived authigenic carbonates from modern and paleoseeps on the Cascadia margin: Mechanisms of formation and diagenetic signals", Tracing Phanerozoic hydrocarbon seepage from local basins to the global Earth system. Vol. 390(0), pp. 52-67.
Abstract: Authigenic carbonate precipitation occurs within marine sediments where sulfate-dependent anaerobic methane oxidation occurs. Geochemical and isotopic analyses of authigenic carbonates are commonly used as indicators of carbon sources and environmental conditions present during carbonate formation, but burial diagenesis and recrystallization can overprint these signals. Plane polarized light (PPL) and cathodoluminescent (CL) petrography allows for detailed characterization of carbonate phases and their subsequent alteration. Petrographic, isotopic, and geochemical characteristics of modern offshore authigenic carbonates from central and northern Cascadia are compared with Oligocene–Pliocene fossil seep carbonates uplifted on the Olympic Peninsula. Coupled analyses show the value and complexity of separating primary vs. secondary signals with relevance to understanding fluid-burial history in methane seep provinces on tectonically active convergent margins. The modern, offshore, near-seafloor diagenetic environment (S. Hydrate Ridge and Barkley Canyon) is dominated by acicular and microcrystalline aragonite and high-Mg calcite (HMC, textgreater 12 mol % Mg). PPL and CL data illustrate that aragonite and HMC phases recrystallize to intermediate-Mg calcite (IMC, 5–12 mol% Mg) during burial and diagenesis and eventually to low-Mg calcite (LMC, 18O attributable to elevated fluid temperatures during recrystallization.
BibTeX:
@article{Joseph2013,
  author = {Joseph, C and Campbell, K A and Torres, M E and Martin, R A and Pohlman, J W and Riedel, M and Rose, K},
  title = {Methane-derived authigenic carbonates from modern and paleoseeps on the Cascadia margin: Mechanisms of formation and diagenetic signals},
  journal = {Tracing Phanerozoic hydrocarbon seepage from local basins to the global Earth system},
  year = {2013},
  volume = {390},
  number = {0},
  pages = {52--67},
  url = {http://www.sciencedirect.com/science/article/pii/S0031018213000333},
  doi = {10.1016/j.palaeo.2013.01.012}
}
Kinsey JC and German CR (2013), "Sustained volcanically-hosted venting at ultraslow ridges: Piccard Hydrothermal Field, Mid-Cayman Rise", Earth and Planetary Science Letters. Vol. 380(0), pp. 162-168.
Abstract: At slow spreading mid-ocean ridges sustained submarine venting and the deposition of large seafloor massive sulfide deposits have previously been ascribed to tectonically-controlled hydrothermal circulation unrelated to young volcanic activity. Here, by contrast, we show that the Piccard Hydrothermal Field (PHF), on the ultraslow spreading Mid-Cayman Rise, represents a site of sustained fluid flow and sulfide formation hosted in a neovolcanic setting. The lateral extent and apparent longevity associated with the PHF are comparable to some of the largest tectonically-hosted vent sites known along the slow-spreading Mid-Atlantic Ridge. If such systems recur along all ultraslow ridges, which comprise ∼20% of the ∼55,000 km global ridge crest, potential implications would include (i) a higher probability of locating large, economically valuable, mineral deposits along ultraslow ridges together with (ii) larger fluxes than previously anticipated of chemicals released from high-temperature venting entering the oceans along the Atlantic–Indian Ocean sectors of the deep-ocean thermohaline conveyor.
BibTeX:
@article{Kinsey2013,
  author = {Kinsey, J C and German, C R},
  title = {Sustained volcanically-hosted venting at ultraslow ridges: Piccard Hydrothermal Field, Mid-Cayman Rise},
  journal = {Earth and Planetary Science Letters},
  year = {2013},
  volume = {380},
  number = {0},
  pages = {162--168},
  url = {http://www.sciencedirect.com/science/article/pii/S0012821X13004214},
  doi = {10.1016/j.epsl.2013.08.001}
}
Levin LA, Ziebis W, Mendoza G, Bertics VJ, Washington T, Gonzalez J, Thurber AR, Ebbe B and Lee RW (2013), "Ecological release and niche partitioning under stress:lessons from dorvilleid polychaetes in sulfidic sediments at methane seeps", Deep-Sea Research. Part II: Topical Studies in Oceanography. Vol. 92, pp. 214-233.
Abstract: Organisms inhabiting methane seep sediments are exposed to stress in the form of high levels of hydrogen sulfide, which result mainly from sulfate reduction coupled to anaerobic methane oxidation. Dorvilleidae (Polychaeta) have successfully invaded this ecosystem, and multiple species in divergent genetic clades co-occur at high densities. At methane seeps in the NE Pacific off California and Oregon, the genera Ophryotrocha, Parougia and Exallopus are especially well represented. To test the hypothesis that dorvilleid coexistence is facilitated by niche partitioning through sulfide tolerance and trophic patterns, we examined dorvilleid species-specific patterns of occurrence and nutrition at methane seeps off Eel R. [ER] on the Californian continental slope and at Hydrate Ridge [HR] on the Oregon continental slope, and in two habitats (clam bed and microbial mat) characterized by lower and higher hydrogen sulfide levels, respectively. Microelectrode measurements of hydrogen sulfide enabled characterization of environmental sulfide levels for species sampled in background sediment cores and in colonization trays. Dorvilleids tolerated H2S levels from 10 μM to over 2.6 mM, with the majority of species inhabiting sediments with similar environmental H2S concentrations (median 85–100 μM). Dorvilleid species richness was greater at HR than ER, but did not differ between clam bed and microbial mat habitats. Species distribution patterns reflected preferences for ER clam bed (lower sulfide levels), ER mat and HR clam bed (moderate sulfide levels), or HR mat (very high sulfide levels). Nutritional patterns, including trophic diversity and functional similarity, were examined using community stable isotope metrics based on δ15N and δ13C. Within each region, dorvilleid species exhibited multiple trophic strategies. Co-existing congeners typically exhibited distinct isotope signatures, suggesting trophic partitioning. Trophic diversity and δ15N range for whole assemblages (measured by Total Hull Area and Standard Elliptical Area using species averages) and functional redundancy or species packing (measured as distance to nearest neighbor) among species and individuals were generally higher at ER, where sulfide levels were lower than at HR. In contrast, average trophic diversity among individuals within a species was greater at HR than ER. In colonization experiments involving agar-based manipulations of sulfide in tray sediments that mimicked clam bed and mat conditions, dorvilleids comprised 68% and 48% of colonists at ER and HR, respectively. Dorvilleid species richness was higher in trays that were initially more sulfidic. However, habitat exerted stronger influence on the composition of colonizing dorvilleids than did sulfide additions. In the NE Pacific, regional, habitat and vertical (down-core) variation in hydrogen sulfide creates complex environmental heterogeneity at methane seeps, promoting high diversity of stress-tolerant taxa such as dorvilleid polychaetes.
BibTeX:
@article{Levin2013,
  author = {Levin, L A and Ziebis, W and Mendoza, G and Bertics, V J and Washington, T and Gonzalez, J and Thurber, A R and Ebbe, B and Lee, R W},
  title = {Ecological release and niche partitioning under stress:lessons from dorvilleid polychaetes in sulfidic sediments at methane seeps},
  journal = {Deep-Sea Research. Part II: Topical Studies in Oceanography},
  year = {2013},
  volume = {92},
  pages = {214--233},
  url = {http://www.sciencedirect.com/science/article/pii/S0967064513000635},
  doi = {10.1016/j.dsr2.2013.02.006}
}
Meyer JL, Akerman NH, Proskurowski G and Huber JA (2013), "Microbiological characterization of post-eruption “snowblower” vents at Axial Seamount, Juan de Fuca Ridge", Frontiers in Microbiology. Vol. 4, pp. 153.
Abstract: Microbial processes within the subseafloor can be examined during the ephemeral and uncommonly observed phenomena known as snowblower venting. Snowblowers are characterized by the large quantity of white floc that is expelled from the seafloor following mid-ocean ridge eruptions. During these eruptions, rapidly cooling lava entrains seawater and hydrothermal fluids enriched in geochemical reactants, creating a natural bioreactor that supports a subseafloor microbial “bloom.” Previous studies hypothesized that the eruption-associated floc was made by sulfide-oxidizing bacteria; however, the microbes involved were never identified. Here we present the first molecular analysis combined with microscopy of microbial communities in snowblower vents from samples collected shortly after the 2011 eruption at Axial Seamount, an active volcano on the Juan de Fuca Ridge. We obtained fluid samples and white flocculent material from active snowblower vents as well as orange flocculent material found on top of newly formed lava flows. Both flocculent types revealed diverse cell types and particulates when examined by phase contrast and scanning electron microscopy (SEM). Distinct archaeal and bacterial communities were detected in each sample type through Illumina tag sequencing of 16S rRNA genes and through sequencing of the sulfide oxidation gene, soxB. In fluids and white floc, the dominant bacteria were sulfur-oxidizing Epsilonproteobacteria and the dominant archaea were thermophilic Methanococcales. In contrast, the dominant organisms in the orange floc were Gammaproteobacteria and Thaumarchaeota Marine Group I. In all samples, bacteria greatly outnumbered archaea. The presence of anaerobic methanogens and microaerobic Epsilonproteobacteria in snowblower communities provides evidence that these blooms are seeded by subseafloor microbes, rather than from microbes in bottom seawater. These eruptive events thus provide a unique opportunity to observe subseafloor microbial communities.
BibTeX:
@article{Meyer2013,
  author = {Meyer, J L and Akerman, N H and Proskurowski, G and Huber, J A},
  title = {Microbiological characterization of post-eruption “snowblower” vents at Axial Seamount, Juan de Fuca Ridge},
  journal = {Frontiers in Microbiology},
  year = {2013},
  volume = {4},
  pages = {153},
  doi = {10.3389/fmicb.2013.00153}
}
Mills SW, Mullineaux LS, Beaulieu SE and Adams DK (2013), "Persistent effects of disturbance on larval patterns in the plankton after an eruption on the East Pacific Rise", Marine Ecology Progress Series. Vol. 491, pp. 67-76.
Abstract: To predict how benthic communities will respond to disturbance, it is necessary to understand how disturbance affects the planktonic larval supply available to recolonize the area. Deep-sea hydrothermal vent fauna along the East Pacific Rise (EPR) experience frequent local extinctions due to tectonic and magmatic events, but the effects on regional larval abundance and diversity are unknown. We had been monitoring larvae at 9°50'N on the EPR prior to the 2006 eruption and were able to resume collections shortly afterward. We found that many species that were common before the eruption became significantly less so afterward, whereas a few other species experienced a transient spike in abundance. Surprisingly, overall species richness in the plankton was high 9 mo after the eruption, but then decreased sharply after 1 yr and had not returned to pre-eruption levels after 2 yr. These results suggest that recovery from disturbance may continue to be affected by limited larval supply even several years after a disturbance event. This delay in recovery means that larvae of pioneer species may dominate potential colonists, even after benthic habitats have transitioned to conditions that favor later-successional species. Moreover, the combined effects of natural and anthropogenic disturbance (e.g. mining) would be likely to cause more profound and long-lasting changes than either event alone. Our results indicate that we do not have sufficient data to predict the timing of recovery after disturbance in the deep sea, even in a well-studied vent system.
BibTeX:
@article{Mills2013,
  author = {Mills, S W and Mullineaux, L S and Beaulieu, S E and Adams, D K},
  title = {Persistent effects of disturbance on larval patterns in the plankton after an eruption on the East Pacific Rise},
  journal = {Marine Ecology Progress Series},
  year = {2013},
  volume = {491},
  pages = {67--76},
  doi = {10.3354/meps10463}
}
Nye V, Copley J, Plouviez S and Van Dover CL (2013), "A new species of Lebbeus (Crustacea: Decapoda: Caridea: Hippolytidae) from the Von Damm Vent Field, Caribbean Sea", Journal of the Marine Biological Association of the United Kingdom., may, 2013. Vol. 93(3), pp. 741-751.
Abstract: A new species of the hippolytid shrimp genus Lebbeus White, 1847 is described from the Von Damm Vent Field (VDVF) on the Mid-Cayman Spreading Centre, Caribbean Sea, at 2294 m water depth. Lebbeus virentova sp. nov. is defined and illustrated from seven specimens, with brief notes on its distribution and habitat. Molecular phylogenetic data from the COI mDNA region are used to analyse the species' phylogenetic position, and its morphology is compared with previously described species. This new species represents the second family of caridean shrimp to be reported from the VDVF. Lebbeus virentova sp. nov. is the eighth member of the genus to be described from hydrothermal vents and appears to be the first hippolytid shrimp at a vent field known from outside the Pacific Ocean.
BibTeX:
@article{Nye2013,
  author = {Nye, Verity and Copley, J and Plouviez, S and Van Dover, C L},
  title = {A new species of Lebbeus (Crustacea: Decapoda: Caridea: Hippolytidae) from the Von Damm Vent Field, Caribbean Sea},
  journal = {Journal of the Marine Biological Association of the United Kingdom},
  year = {2013},
  volume = {93},
  number = {3},
  pages = {741--751},
  doi = {10.1017/S0025315412000884}
}
Peterson RN, Viso RF, MacDonald IR and Joye SB (2013), "On the utility of radium isotopes as tracers of hydrocarbon discharge", Marine Chemistry. Vol. 156(SI), pp. 98-107.
Abstract: Natural seepage of hydrocarbons commonly occurs in the Gulf of Mexico and numerous other locations around the world's oceans. In-situ quantification of discharge and transport of these hydrocarbons through the water column is somewhat limited by a lack of available tracers. Here, we consider the utility of using radium isotopes, which are commonly enriched in formation fluids contained within hydrocarbon reservoirs, as tracers of hydrocarbons discharged into the deep ocean. During a cruise in November/December 2010 through the Gulf of Mexico, radium isotopes (224Ra and 226Ra) revealed anomalous concentrations in near-bottom samples associated with the presence of hydrocarbons at several sites where hydrocarbon seepage was known to occur and observed real-time via the human-occupied vehicle Alvin. These tracers also indicated the presence of near-bottom hydrocarbons in the vicinity of the Macondo wellhead where the Deepwater Horizon blowout occurred months earlier. These hydrocarbons are presumed to originate from nearby gas seeps later identified by water column sonar returns. The short half-life of 224Ra (3.66 days) suggests that anomalously high unsupported activities of this isotope must be derived from recent (days to weeks) discharge. Sampling at the sediment–water interface confirmed that the source of the water column radium isotope anomalies is likely benthic sources. These results suggest that radium isotopes may serve as useful tracers of hydrocarbons in such an environment, and we outline steps required to quantify discharge rates and transport time scales with these tracers.
BibTeX:
@article{Peterson2013,
  author = {Peterson, R N and Viso, R F and MacDonald, I R and Joye, S B},
  title = {On the utility of radium isotopes as tracers of hydrocarbon discharge},
  journal = {Marine Chemistry},
  year = {2013},
  volume = {156},
  number = {SI},
  pages = {98--107},
  doi = {10.1016/j.marchem.2013.02.008}
}
Reiswig HM and Stone RP (2013), "New glass sponges (Porifera: Hexactinellida) from deep waters of the central Aleutian Islands, Alaska", Zootaxa. Vol. 3628, pp. 1-64.
Abstract: Hexactinellida from deep-water communities of the central Aleutian Islands, Alaska, are described. They were mostly collected by the remotely operated vehicle 'Jason II' from 494–2311 m depths during a 2004 RV 'Roger Revelle' expedition, but one shallow-water species collected with a shrimp trawl from 155 m in the same area is included. The excellent condition of the ROV-collected specimens enabled valuable redescription of some species previously known only from badly damaged specimens. New taxa include one new genus and eight new species in five families. Farreidae consist of two new species, Farrea aleutiana and F. aspondyla. Euretidae consists of only Pinulasma fistulosum n. gen., n. sp. Tretodictyidae include only Tretodictyum amchitkensis n. sp. Euplectellidae consists of only the widespread species Regadrella okinoseana Ijima, reported here over 3,700 km from its closest previously known occurrence. The most diverse family, Rossellidae, consists of Aulosaccus ijimai (Schulze), Aulosaccus schulzei Ijima, Bathydorus sp. (young stage not determinable to species), Caulophacus (Caulophacus) adakensis n. sp., Acanthascus koltuni n. sp., Staurocalyptus psilosus n. sp., Staurocalyptus tylotus n. sp. and Rhabdocalyptus mirabilis Schulze. We present argument for reinstatement of the abolished rossellid subfamily Acanthascinae and return of the subgenera Staurocalyptus Ijima and Rhabdocalyptus Schulze to their previous generic status. These fauna provides important complexity to the hard substrate communities that likely serve as nursery areas for the young stages of commercially important fish and crab species, refuge from predation for both young and adult stages, and also as a focal source of prey for juvenile and adult stages of those same species.
BibTeX:
@article{Reiswig2013,
  author = {Reiswig, H M and Stone, R P},
  title = {New glass sponges (Porifera: Hexactinellida) from deep waters of the central Aleutian Islands, Alaska},
  journal = {Zootaxa},
  year = {2013},
  volume = {3628},
  pages = {1--64},
  doi = {10.11646/zootaxa.3628.1.1}
}
Sen A, Becker EL, Podowski EL, Wickes LN, Ma S, Mullaugh KM, Hourdez S, Luther GW and Fisher CR (2013), "Distribution of mega fauna on sulfide edifices on the Eastern Lau Spreading Center and Valu Fa Ridge", Deep-Sea Research. Part I: Oceanographic Research Papers. Vol. 72(0), pp. 48-60.
Abstract: Hydrothermal vent sulfide edifices contain some of the most extreme thermal and chemical conditions in which animals are able to live. As a result, sulfide edifices in the East Pacific Rise, Juan de Fuca Ridge, and Mid Atlantic Ridge vent systems often contain distinct faunal assemblages. In this study, we used high-resolution imagery and in-situ physico-chemical measurements within the context of a Geographic Information System (GIS) to examine community structure and niche differentiation of dominant fauna on sulfide edifices in the Eastern Lau Spreading Center (ELSC) and Valu Fa Ridge (VFR) in the Western Pacific Ocean. Our results show that ELSC and VFR sulfide edifices host two distinct types of communities. One type, that covers the majority of sulfide edifice faces, is overall very similar to nearby lava communities and biomass is dominated by the same chemoautotrophic symbiont-containing molluscs that dominate lava communities, namely the provannid gastropods Alviniconcha spp. and Ifremeria nautilei and the mytilid bivalve Bathymodiolus brevior. The spatial distribution of the dominant molluscs is often a variation of the pattern of concentric rings observed on lavas, with Alviniconcha spp. at the tops of edifices where exposure to vent flow is the highest, and I. nautilei and B. brevior below. Our physico-chemical measurements indicate that because of rapid dispersion of vent fluid, habitable area for symbiont-containing fauna is quite limited on sulfide edifices, and the realized niches of the mollusc groups are narrower on sulfide edifices than on lavas. We suggest that competition plays an important role in determining the realized distributions of the mollusc groups on edifices. The other habitat, present in small patches of presumably hot, new anhydrite, is avoided by the dominant symbiont-containing molluscs and inhabited by crabs, shrimp and polynoids that are likely more heat tolerant. The ratio of sulfide concentration to temperature anomaly of vent fluids was significantly different between sulfide edifice sites and lava sites in the southern vent fields but not in the northern vent fields. We suggest that this is due to increased sulfide consumption by a large microbial consortium associated with the more friable andesitic lava substrates in the south.
BibTeX:
@article{Sen2013,
  author = {Sen, A and Becker, E L and Podowski, E L and Wickes, L N and Ma, S and Mullaugh, K M and Hourdez, S and Luther, G W and Fisher, C R},
  title = {Distribution of mega fauna on sulfide edifices on the Eastern Lau Spreading Center and Valu Fa Ridge},
  journal = {Deep-Sea Research. Part I: Oceanographic Research Papers},
  year = {2013},
  volume = {72},
  number = {0},
  pages = {48--60},
  url = {http://www.sciencedirect.com/science/article/pii/S0967063712002233},
  doi = {10.1016/j.dsr.2012.11.003}
}
Tontini FC, de Ronde CEJ, Kinsey JC, Soule A, Yoerger D and Cocchi L (2013), "Geophysical modeling of collapse-prone zones at Rumble III seamount, southern Pacific Ocean, New Zealand", Geochemistry, Geophysics, Geosystems. Vol. 14(10), pp. 4667-4680.
Abstract: Catastrophic collapses of submarine volcanoes have the potential to generate major tsunami, threatening many coastal populations. Recognizing the difficulties surrounding anticipations of these events, quantitative assessment of collapse-prone regions based on detailed morphological, geological, and geophysical mapping can still provide important information about the hazards associated with these collapses. Rumble III is one of the shallowest, and largest, submarine volcanoes found along the Kermadec arc, and is both volcanically and hydrothermally active. Previous surveys have delineated major collapse features at Rumble III; based on time-lapse bathymetry, dramatic changes in the volcano morphology have been shown to have occurred over the interval 2007–2009. Furthermore, this volcano is located just ∼300 km from the east coast of the North Island of New Zealand. Here, we present a geophysical model for Rumble III that provides the locations and sizes of potential weak regions of this volcano. Shipborne and near-seafloor geological and geophysical data collected by the AUV Sentry are used to determine the subsurface distribution of weak and unstable volcanic rocks. The resulting model provides evidence for potentially unstable areas located in the Southeastern flank of this volcano which should be included in future hazard predictions.
BibTeX:
@article{Tontini2013,
  author = {Tontini, F C and de Ronde, C E J and Kinsey, J C and Soule, A and Yoerger, D and Cocchi, L},
  title = {Geophysical modeling of collapse-prone zones at Rumble III seamount, southern Pacific Ocean, New Zealand},
  journal = {Geochemistry, Geophysics, Geosystems},
  year = {2013},
  volume = {14},
  number = {10},
  pages = {4667--4680},
  url = {http://dx.doi.org/10.1002/ggge.20278},
  doi = {10.1002/ggge.20278}
}
Tucholke BE, Humphris SE and Dick HJB (2013), "Cemented mounds and hydrothermal sediments on the detachment surface at Kane Megamullion: A new manifestation of hydrothermal venting", Geochemistry, Geophysics, Geosystems. Vol. 14, pp. 3352-3378.
Abstract: Long-lived detachment faults are now known to be important in tectonic evolution of slow-spreading mid-ocean ridges, and there is increasing evidence that fluid flow plays a critical role in development of detachment systems. Here we document a new manifestation of low-temperature hydrothermal venting associated with the detachment fault that formed Kane Megamullion ∼3.3–2.1 m.y. ago in the western rift-valley wall of the Mid-Atlantic Ridge. Hydrothermal effects on the detachment surface include (1) cemented mounds of igneous rock and chalk debris containing hydrothermal Mn oxides and Fe oxyhydroxides, and (2) layered deposits of similar Fe-Mn minerals ± interbedded chalks. Mounds are roughly conical, ∼1–10 m high, and contain primarily basalts with lesser gabbro, serpentinite, and polymict breccia. The layered Fe-Mn-rich sediments are flat-bedded to contorted and locally are buckled into low-relief linear or polygonal ridges. We propose that the mounds formed where hydrothermal fluids discharged through the detachment hanging wall near the active fault trace. Hydrothermal precipitates cemented hanging-wall debris and welded it to the footwall, and this debris persisted as mounds as the footwall was exhumed and surrounding unconsolidated material sloughed off the sloping detachment surface. Some of the layered Fe-Mn-rich deposits may have precipitated from fluids discharging from the hanging-wall vents, but they also precipitated from low-temperature fluids venting from the exposed footwall through overlying chalks. Observed natural disturbance and abnormally thin hydrogenous Fe-Mn crusts on some contorted, hydrothermal Fe-Mn-rich chalks on ∼2.7 Ma crust suggest diffuse venting that is geologically recent. Results of this study imply that there are significant fluid pathways through all parts of detachment systems and that low-temperature venting through fractured detachment footwalls may continue for several million years off-axis.
BibTeX:
@article{Tucholke2013,
  author = {Tucholke, B E and Humphris, S E and Dick, H J B},
  title = {Cemented mounds and hydrothermal sediments on the detachment surface at Kane Megamullion: A new manifestation of hydrothermal venting},
  journal = {Geochemistry, Geophysics, Geosystems},
  year = {2013},
  volume = {14},
  pages = {3352--3378},
  doi = {10.1002/ggge.20186}
}
Tunnicliffe V, Tyler J and Dower JF (2013), "Population ecology of the tonguefish Symphurus thermophilus (Pisces; Pleuronectiformes; Cynoglossidae) at sulphur-rich hydrothermal vents on volcanoes of the northern Mariana Arc", Deep-Sea Research. Part II: Topical Studies in Oceanography. Vol. 92, pp. 172-182.
Abstract: Flatfish are a major component of the hydrothermal vent community on three seamounts of the northern Mariana Volcanic Arc in the northwest Pacific. Nikko, Kasuga-2 and Daikoku seamounts host vent fields between 375 and 480 m depth where high temperature vents release molten sulphur. The small cynoglossid tonguefish, Symphurus thermophilus Munroe and Hashimoto, is ubiquitous in all vent habitats observed on these seamounts: among extensive fields of tubeworms and mussels and on solid sulphur surfaces on Nikko; on sulphur-rich sediments and barnacle-covered boulders on Kasuga-2; and on recent sulphur flows and on broad areas of loose and semi-consolidated sediments on Daikoku. We recorded repeated forays by individuals onto flows of molten sulphur as these surfaces cooled. Based on observations using ROVs, the mean density is 90 fish/m2 with maximum counts over 200 fish/m2 on Daikoku sediments. Compared to collected tonguefish from Daikoku and Kasuga-2, those from Nikko have significantly greater lengths and, on average, six times the mass. Otolith data indicate upper ages of 13 years with Nikko tonguefish growing significantly faster. Diets of tonguefish on the three seamounts reflect the different habitats and prey availability; in Daikoku specimens, small crustaceans and polychaetes are most common while on Nikko, gut contents are predominantly larger shrimp. We made the unusual observation of stunned midwater fish falling to the seafloor near the vents where S. thermophilus immediately attacked them. This tonguefish has a wide diet range and foraging behaviour that likely influence the differing growth rates and sizes of fish inhabiting the different vent sites. Limited genetic data suggest that larval exchange probably occurs among sites where the common habitat factor is high levels of elemental sulphur forming hard and partly unconsolidated substrata. Here, in the northern range of the Mariana Trench Marine National Monument, S. thermophilus, despite having an unusually broad habitat association, may be restricted in its overall range to this region of isolated volcanoes with active hydrothermalism.
BibTeX:
@article{Tunnicliffe2013,
  author = {Tunnicliffe, V and Tyler, J and Dower, J F},
  title = {Population ecology of the tonguefish Symphurus thermophilus (Pisces; Pleuronectiformes; Cynoglossidae) at sulphur-rich hydrothermal vents on volcanoes of the northern Mariana Arc},
  journal = {Deep-Sea Research. Part II: Topical Studies in Oceanography},
  year = {2013},
  volume = {92},
  pages = {172--182},
  url = {http://www.sciencedirect.com/science/article/pii/S0967064513000465},
  doi = {10.1016/j.dsr2.2013.01.026}
}
Wagner JKS, McEntee MH, Brothers LL, German CR, Kaiser CL, Yoerger DR and Van Dover CL (2013), "Cold-seep habitat mapping: High-resolution spatial characterization of the Blake Ridge Diapir seep field", Deep-Sea Research. Part II: Topical Studies in Oceanography. Vol. 92(SI), pp. 183-188.
Abstract: Relationships among seep community biomass, diversity, and physiographic controls such as underlying geology are not well understood. Previous efforts to constrain these relationships at the Blake Ridge Diapir were limited to observations from piloted deep-submergence vehicles. In August 2012, the autonomous underwater vehicle (AUV) Sentry collected geophysical and photographic data over a 0.131 km2 area at the Blake Ridge Diapir seeps. A nested survey approach was used that began with a regional or reconnaissance-style survey using sub-bottom mapping systems to locate and identify seeps and underlying conduits. This survey was followed by AUV-mounted sidescan sonar and multibeam echosounder systems mapping on a mesoscale to characterize the seabed physiography. At the most detailed survey level, digital photographic imaging was used to resolve sub-meter characteristics of the biology. Four pockmarks (25–70 m diameter) were documented, each supporting chemosynthetic communities. Concentric zonation of mussels and clams suggests the influence of chemical gradients on megafaunal distribution. Data collection and analytical techniques used here yield high-resolution habitat maps that can serve as baselines to constrain temporal evolution of seafloor seeps, and to inform ecological niche modeling and resource management.
BibTeX:
@article{Wagner2013,
  author = {Wagner, J K S and McEntee, M H and Brothers, L L and German, C R and Kaiser, C L and Yoerger, D R and Van Dover, C L},
  title = {Cold-seep habitat mapping: High-resolution spatial characterization of the Blake Ridge Diapir seep field},
  journal = {Deep-Sea Research. Part II: Topical Studies in Oceanography},
  year = {2013},
  volume = {92},
  number = {SI},
  pages = {183--188},
  doi = {10.1016/j.dsr2.2013.02.008}
}
Waters CL, Sims KWW, Klein EM, White SM, Reagan MK and Girard G (2013), "Sill to surface: Linking young off-axis volcanism with subsurface melt at the overlapping spreading center at 9°03′N East Pacific Rise", Earth and Planetary Science Letters. Vol. 369–370(0), pp. 59-70.
Abstract: No young, off-axis, mid-ocean ridge lavas have yet been directly linked to underlying off-axis melt bodies. In this study, we present new measurements of 238U–230Th–226Ra–210Pb isotope compositions for a suite of lavas from the overlapping spreading center (OSC) at 9°03′N on the East Pacific Rise (EPR). These lavas span a large range of compositions, from basalt to dacite, and include both axial and off-axis samples recovered from a prominent, axis-parallel pillow ridge and a flat-topped seamount that overlie the westernmost extent of a 4-km-wide melt lens (Kent et al., 2000). We report 210Pb excesses in axial basalts and basaltic andesites, which we suggest results from gas-magma fractionation of 222Rn from 226Ra beneath dacite magmas. In addition, our U-series ages agree with visual observations, indicating that while most recent volcanic activity occurs at the spreading axis, active volcanism also occurs away from the axis. Specifically, the off-axis pillow ridge and seamount samples overlying the off-axis subsurface melt body have eruption ages of less than 8 ka, and likely as young as 1 ka, despite being located on crust that has a spreading age of ˜75 ka. The young ages of these lavas, combined with existing geological, geochemical and geophysical constraints, provide evidence for a genetic link between the pillow ridge and seamount lavas and the seismically imaged, underlying off-axis melt lens. This link demonstrates that off-axis volcanism does not necessarily come from a sub-axial magma body and can be sourced directly from off-axis magma bodies.
BibTeX:
@article{Waters2013,
  author = {Waters, C L and Sims, K W W and Klein, E M and White, S M and Reagan, M K and Girard, G},
  title = {Sill to surface: Linking young off-axis volcanism with subsurface melt at the overlapping spreading center at 9°03′N East Pacific Rise},
  journal = {Earth and Planetary Science Letters},
  year = {2013},
  volume = {369–370},
  number = {0},
  pages = {59--70},
  url = {http://www.sciencedirect.com/science/article/pii/S0012821X13001209},
  doi = {10.1016/j.epsl.2013.03.006}
}
Yuecel M and Luther GW (2013), "Temporal trends in vent fluid iron and sulfide chemistry following the 2005/2006 eruption at East Pacific Rise, 9 degrees 50 ' N", Geochemistry, Geophysics, Geosystems. Vol. 14(4), pp. 759-765.
Abstract: The chemistry of vent fluids that emanate to the seafloor undergoes dramatic changes after volcanic eruptions. Data on these changes are still limited, but the best studied example is the East Pacific Rise (EPR) at 9°50′N, where the temporal evolution of the vent fluid chemistry after the 1991/1992 eruption was documented. The area underwent another eruption sequence during late 2005/early 2006, and here we show that a similar evolution is recurring in the iron and sulfide contents of the high-temperature fluids sampled in June 2006, January 2007, and June 2008. The vents have had increasing dissolved iron and decreasing acid-volatile sulfide (free sulfide plus FeS) concentrations with 1 order of magnitude variation. In addition, chromium reducible sulfide (mainly pyrite) also had fivefold decreasing concentrations over the 3 years. Our results confirm a pattern that was noted only once before for 9°50′N EPR and emphasize the dramatic yearly variability in the concentrations of iron-sulfur species emanating from vents.
BibTeX:
@article{Yuecel2013,
  author = {Yuecel, M and Luther, G W},
  title = {Temporal trends in vent fluid iron and sulfide chemistry following the 2005/2006 eruption at East Pacific Rise, 9 degrees 50 ' N},
  journal = {Geochemistry, Geophysics, Geosystems},
  year = {2013},
  volume = {14},
  number = {4},
  pages = {759--765},
  doi = {10.1002/ggge.20088}
}
Baker ET, Chadwick WW, Cowen JP, Dziak RP, Rubin KH and Fornari DJ (2012), "Hydrothermal Discharge During Submarine Eruptions THE IMPORTANCE OF DETECTION, RESPONSE, AND NEW TECHNOLOGY", Oceanography. ROCKVILLE; P.O. BOX 1931, ROCKVILLE, MD USA, mar, 2012. Vol. 25(1), pp. 128-141. OCEANOGRAPHY SOC.
Abstract: Submarine volcanic eruptions and intrusions construct new oceanic crust and build long chains of volcanic islands and vast submarine plateaus. Magmatic events are a primary agent for the transfer of heat, chemicals, and even microbes from the crust to the ocean, but the processes that control these transfers are poorly understood. The 1980s discovery that mid-ocean ridge eruptions are often associated with brief releases of immense volumes of hot fluids ("event plumes") spurred interest in methods for detecting the onset of eruptions or intrusions and for rapidly organizing seagoing response efforts. Since then, some 35 magmatic events have been recognized and responded to on mid-ocean ridges and at seamounts in both volcanic arc and intraplate settings. Field responses at mid-ocean ridges have found that event plumes occur over a wide range of eruption styles and sizes, and thus may be a common consequence of ridge eruptions. The source(s) of event plume fluids are still debated. Eruptions detected at ridges generally have high effusion rates and short durations (hours to days), whereas field responses at arc volcanic cones have found eruptions with very low effusion rates and durations on the scale of years. New approaches to the study of submarine magmatic events include the development of autonomous vehicles for detection and response, and the establishment of permanent seafloor observatories at likely future eruption sites.
BibTeX:
@article{Baker2012,
  author = {Baker, E T and Chadwick, W W and Cowen, J P and Dziak, R P and Rubin, K H and Fornari, D J},
  title = {Hydrothermal Discharge During Submarine Eruptions THE IMPORTANCE OF DETECTION, RESPONSE, AND NEW TECHNOLOGY},
  journal = {Oceanography},
  publisher = {OCEANOGRAPHY SOC},
  year = {2012},
  volume = {25},
  number = {1},
  pages = {128--141},
  doi = {10.5670/oceanog.2012.11}
}
Beinart RA, Sanders JG, Faure B, Sylva SP, Lee RW, Becker EL, Gartman A, Luther GW, Seewald JS, Fisher CR and Girguis PR (2012), "Evidence for the role of endosymbionts in regional-scale habitat partitioning by hydrothermal vent symbioses", Proceedings of the National Academy of Sciences of the United States of America., nov, 2012. Vol. 109(47), pp. E3241-E3250.
Abstract: Deep-sea hydrothermal vents are populated by dense communities of animals that form symbiotic associations with chemolithoautotrophic bacteria. To date, our understanding of which factors govern the distribution of host/symbiont associations (or holobionts) in nature is limited, although host physiology often is invoked. In general, the role that symbionts play in habitat utilization by vent holobionts has not been thoroughly addressed. Here we present evidence for symbiont-influenced, regional-scale niche partitioning among symbiotic gastropods (genus Alviniconcha) in the Lau Basin. We extensively surveyed Alviniconcha holobionts from four vent fields using quantitative molecular approaches, coupled to characterization of high-temperature and diffuse vent-fluid composition using gastight samplers and in situ electrochemical analyses, respectively. Phylogenetic analyses exposed cryptic host and symbiont diversity, revealing three distinct host types and three different symbiont phylotypes (one ε-proteobacteria and two γ-proteobacteria) that formed specific associations with one another. Strikingly, we observed that holobionts with ε-proteobacterial symbionts were dominant at the northern fields, whereas holobionts with γ-proteobacterial symbionts were dominant in the southern fields. This pattern of distribution corresponds to differences in the vent geochemistry that result from deep subsurface geological and geothermal processes. We posit that the symbionts, likely through differences in chemolithoautotrophic metabolism, influence niche utilization among these holobionts. The data presented here represent evidence linking symbiont type to habitat partitioning among the chemosynthetic symbioses at hydrothermal vents and illustrate the coupling between subsurface geothermal processes and niche availability.
BibTeX:
@article{Beinart2012,
  author = {Beinart, R A and Sanders, J G and Faure, B and Sylva, S P and Lee, R W and Becker, E L and Gartman, A and Luther, G W and Seewald, J S and Fisher, C R and Girguis, P R},
  title = {Evidence for the role of endosymbionts in regional-scale habitat partitioning by hydrothermal vent symbioses},
  journal = {Proceedings of the National Academy of Sciences of the United States of America},
  year = {2012},
  volume = {109},
  number = {47},
  pages = {E3241--E3250},
  doi = {10.1073/pnas.1202690109}
}
Bernardino AF, Levin LA, Thurber AR and Smith CR (2012), "Comparative Composition, Diversity and Trophic Ecology of Sediment Macrofauna at Vents, Seeps and Organic Falls", PLoS ONE., apr, 2012. Vol. 7(4), pp. e33515. Public Library of Science.
Abstract: Sediments associated with hydrothermal venting, methane seepage and large organic falls such as whale, wood and plant detritus create deep-sea networks of soft-sediment habitats fueled, at least in part, by the oxidation of reduced chemicals. Biological studies at deep-sea vents, seeps and organic falls have looked at macrofaunal taxa, but there has yet to be a systematic comparison of the community-level attributes of sediment macrobenthos in various reducing ecosystems. Here we review key similarities and differences in the sediment-dwelling assemblages of each system with the goals of (1) generating a predictive framework for the exploration and study of newly identified reducing habitats, and (2) identifying taxa and communities that overlap across ecosystems. We show that deep-sea seep, vent and organic-fall sediments are highly heterogeneous. They sustain different geochemical and microbial processes that are reflected in a complex mosaic of habitats inhabited by a mixture of specialist (heterotrophic and symbiont-associated) and background fauna. Community-level comparisons reveal that vent, seep and organic-fall macrofauna are very distinct in terms of composition at the family level, although they share many dominant taxa among these highly sulphidic habitats. Stress gradients are good predictors of macrofaunal diversity at some sites, but habitat heterogeneity and facilitation often modify community structure. The biogeochemical differences across ecosystems and within habitats result in wide differences in organic utilization (i.e., food sources) and in the prevalence of chemosynthesis-derived nutrition. In the Pacific, vents, seeps and organic-falls exhibit distinct macrofaunal assemblages at broad-scales contributing to ß diversity. This has important implications for the conservation of reducing ecosystems, which face growing threats from human activities.
BibTeX:
@article{Bernardino2012,
  author = {Bernardino, A F and Levin, L A and Thurber, A R and Smith, C R},
  title = {Comparative Composition, Diversity and Trophic Ecology of Sediment Macrofauna at Vents, Seeps and Organic Falls},
  journal = {PLoS ONE},
  publisher = {Public Library of Science},
  year = {2012},
  volume = {7},
  number = {4},
  pages = {e33515},
  url = {http://dx.doi.org/10.1371/journal.pone.0033515},
  doi = {10.1371/journal.pone.0033515}
}
Brandl PA, Beier C, Regelous M, Abouchami W, Haase KM, Garbe-Schonberg D and Galer SJG (2012), "Volcanism on the flanks of the East Pacific Rise: Quantitative constraints on mantle heterogeneity and melting processes", Chemical Geology., feb, 2012. Vol. 298–299(0), pp. 41-56.
Abstract: We present major and trace element and Sr, Nd and triple-spike Pb isotope data for 17 fresh volcanic glasses from Seamount 6, a 10-km diameter seamount located 140 km east of the East Pacific Rise at 12°45′N. Geological and geochronological evidence show that magma compositions evolved from tholeiitic basalts to alkalic basalts and basaltic trachyandesites during the 1–2 Ma active lifetime of the seamount. Major and trace element compositions in Seamount 6 lavas vary systematically with isotope ratios; the youngest lavas with the highest incompatible trace element concentrations have the highest La/Yb, Nb/Zr, K2O/TiO2, 87Sr/86Sr, 206Pb/204Pb and the lowest 143Nd/144Nd, MgO and CaO. The range in element concentrations, incompatible element ratios, and isotope compositions in Seamount 6 lavas exceeds that observed in lavas erupted at the adjacent ridge axis, and is comparable to the range in lava compositions reported from all near-ridge seamounts studied to date. The observed range in lava compositions is consistent with mixing between enriched and depleted melts at shallow levels in the crust. The inferred difference in composition between these mixing endmembers cannot be explained by variable degrees of melting of a single source composition, and requires that the upper mantle is extremely heterogeneous on the scale of the melting region beneath a single seamount. We can show that the range in composition of EPR seamount lavas cannot be generated by melting of variably heterogeneous mantle in which enriched and depleted materials contribute equally to melting (source mixing). Instead, the trace element and isotope compositions of seamount lavas can be reproduced by melting models in which more enriched, fertile mantle lithologies are preferentially melted during mantle upwelling. At progressively lower degrees of melting, erupted lavas are thus more enriched in incompatible trace elements, have higher La/Yb, K/Ti, 87Sr/86Sr ratios and lower 143Nd/144Nd. If this is a common process, then mantle-derived magmas are unlikely to inherit the average incompatible trace element and isotope composition of their mantle source, which is likely to be significantly more depleted, nor will they display the full range of compositions present in the mantle melting region. These results have implications for the way in which oceanic basalts can be used to infer the composition of the upper mantle.
BibTeX:
@article{Brandl2012,
  author = {Brandl, P A and Beier, C and Regelous, M and Abouchami, W and Haase, K M and Garbe-Schonberg, D and Galer, S J G},
  title = {Volcanism on the flanks of the East Pacific Rise: Quantitative constraints on mantle heterogeneity and melting processes},
  journal = {Chemical Geology},
  year = {2012},
  volume = {298–299},
  number = {0},
  pages = {41--56},
  url = {http://dx.doi.org/10.1016/j.chemgeo.2011.12.015},
  doi = {10.1016/j.chemgeo.2011.12.015}
}
Caress DW, Clague DA, Paduan JB, Martin JF, Dreyer BM, Chadwick WW, Denny A and Kelley DS (2012), "Repeat bathymetric surveys at 1-metre resolution of lava flows erupted at Axial Seamount in April 2011", Nature Geoscience. NEW YORK; 75 VARICK ST, 9TH FLR, NEW YORK, NY 10013-1917 USA, jul, 2012. Vol. 5(7), pp. 483-488. NATURE PUBLISHING GROUP.
Abstract: At sites with frequent submarine volcanic activity, it is difficult to discern between new and pre-existing lava flows. In particular, the distribution of the fissures from which lava erupts, the routes taken by lava flows and the relationship between the new flows and the pre-existing seafloor bathymetry are often unclear. The volcanic and hydrothermal systems of Axial Seamount submarine volcano in the Pacific Ocean have been studied intensively since eruptions were detected in 1998 (refs 1, 2) and 2011 (ref. 3). Here we combine pre- and post-eruption bathymetric surveys3, 4, 5, 6, 7, 8, with 1-m lateral resolution and 0.2-m vertical precision, to precisely map the extent and thickness of the lava flows, calculate the volume of lava and unambiguously identify eruptive fissures from the April 2011 eruption. Where the new lava flows extend beyond the boundaries of the repeated surveys, we use shipboard multibeam surveys to map the flows with lower resolution. We show that the eruption produced both sheet and lobate flows associated with high eruption rates and low-eruption-rate pillow mounds. We find that lava flows erupted from new as well as existing fissures and tended to reoccupy existing flow channels. This reoccupation makes it difficult to map submarine flows produced during one eruption without before-and-after bathymetric surveys.
BibTeX:
@article{Caress2012,
  author = {Caress, D W and Clague, D A and Paduan, J B and Martin, J F and Dreyer, B M and Chadwick, W W and Denny, Alden and Kelley, D S},
  title = {Repeat bathymetric surveys at 1-metre resolution of lava flows erupted at Axial Seamount in April 2011},
  journal = {Nature Geoscience},
  publisher = {NATURE PUBLISHING GROUP},
  year = {2012},
  volume = {5},
  number = {7},
  pages = {483--488},
  doi = {10.1038/ngeo1496}
}
Chadwick WW, Nooner SL, Butterfield DA and Lilley MD (2012), "Seafloor deformation and forecasts of the April 2011 eruption at Axial Seamount", Nature Geoscience. NEW YORK; 75 VARICK ST, 9TH FLR, NEW YORK, NY 10013-1917 USA, jul, 2012. Vol. 5(7), pp. 474-477. NATURE PUBLISHING GROUP.
Abstract: Axial Seamount is an active submarine volcano located at the intersection between the Cobb hotspot and the Juan de Fuca spreading centre in the northeast Pacific Ocean1, 2. The volcano has been closely monitored since it erupted in 1998 (refs 3, 4). Since then, Axial Seamount seemed to exhibit a similar inflation–deflation cycle to basaltic volcanoes on land and, on that basis, was expected to erupt again sometime before 2014 or 2020 (refs 5, 6). In April 2011 Axial Seamount erupted. Here we report continuous measurements of ocean bottom pressure that document the deflation–inflation cycle of Axial Seamount between 1998 and 2011. We find that the volcano inflation rate, caused by the intrusion of magma, gradually increased in the months leading up to the 2011 eruption. Sudden uplift occurred 40–55 min before the eruption onset, which we interpret as a precursor event. Based on our measurements of ground deformation through the entire eruption cycle at Axial Seamount, we suggest that another eruption could occur as early as 2018. We propose that the long-term eruptive cycle of Axial Seamount could be more predictable compared with its subaerial counterparts because the volcano receives a relatively steady supply of magma through the Cobb hotspot and because it is located on thin oceanic crust at a spreading plate boundary.
BibTeX:
@article{Chadwick2012,
  author = {Chadwick, W W and Nooner, S L and Butterfield, D A and Lilley, M D},
  title = {Seafloor deformation and forecasts of the April 2011 eruption at Axial Seamount},
  journal = {Nature Geoscience},
  publisher = {NATURE PUBLISHING GROUP},
  year = {2012},
  volume = {5},
  number = {7},
  pages = {474--477},
  doi = {10.1038/ngeo1464}
}
Chadwick WW, Dziak RP, Haxel JH, Embley RW and Matsumoto H (2012), "Submarine landslide triggered by volcanic eruption recorded by in situ hydrophone", Geology. BOULDER; PO BOX 9140, BOULDER, CO 80301-9140 USA, jan, 2012. Vol. 40(1), pp. 51-54. GEOLOGICAL SOC AMER, INC.
Abstract: NW Rota-1 is a submarine volcano in the Mariana volcanic arc that is notable as the site where underwater explosive eruptions were first witnessed in A.D. 2004. After years of continuous low-level eruptive activity, a major landslide occurred at NW Rota-1 in August 2009, triggered by an unusually large eruption that produced 10 times the acoustic energy of the background level of activity. An anomalous earthquake swarm preceded the eruption, suggesting that the sequence started with a magmatic intrusion and associated faulting beneath the volcano. We quantify the size and extent of the landslide using bathymetric resurveys and interpret the timing of events using data from an in situ hydrophone. This is the first instrumental documentation of an earthquake-eruption-landslide sequence at a submarine volcano, and illustrates the close interaction between magmatic activity and mass wasting events in the growth of undersea arc volcanoes.
BibTeX:
@article{Chadwick2012a,
  author = {Chadwick, W W and Dziak, R P and Haxel, J H and Embley, R W and Matsumoto, H},
  title = {Submarine landslide triggered by volcanic eruption recorded by in situ hydrophone},
  journal = {Geology},
  publisher = {GEOLOGICAL SOC AMER, INC},
  year = {2012},
  volume = {40},
  number = {1},
  pages = {51--54},
  doi = {10.1130/G32495.1}
}
Colman A, Sinton JM, White SM, McClinton JT, Bowles JA, Rubin KH, Behn MD, Cushman B, Eason DE, Gregg TKP, Grönvold K, Hidalgo S, Howell J, Neill O and Russo C (2012), "Effects of variable magma supply on mid-ocean ridge eruptions: Constraints from mapped lava flow fields along the Galápagos Spreading Center", Geochemistry, Geophysics, Geosystems. Vol. 13(8), pp. Q08014.
Abstract: Mapping and sampling of 18 eruptive units in two study areas along the Galápagos Spreading Center (GSC) provide insight into how magma supply affects mid-ocean ridge (MOR) volcanic eruptions. The two study areas have similar spreading rates (53 versus 55 mm/yr), but differ by 30% in the time-averaged rate of magma supply (0.3 × 106 versus 0.4 × 106 m3/yr/km). Detailed geologic maps of each study area incorporate observations of flow contacts and sediment thickness, in addition to sample petrology, geomagnetic paleointensity, and inferences from high-resolution bathymetry data. At the lower-magma-supply study area, eruptions typically produce irregularly shaped clusters of pillow mounds with total eruptive volumes ranging from 0.09 to 1.3 km3. At the higher-magma-supply study area, lava morphologies characteristic of higher effusion rates are more common, eruptions typically occur along elongated fissures, and eruptive volumes are an order of magnitude smaller (0.002–0.13 km3). At this site, glass MgO contents (2.7–8.4 wt. %) and corresponding liquidus temperatures are lower on average, and more variable, than those at the lower-magma-supply study area (6.2–9.1 wt. % MgO). The differences in eruptive volume, lava temperature, morphology, and inferred eruption rates observed between the two areas along the GSC are similar to those that have previously been related to variable spreading rates on the global MOR system. Importantly, the documentation of multiple sequences of eruptions at each study area, representing hundreds to thousands of years, provides constraints on the variability in eruptive style at a given magma supply and spreading rate.
BibTeX:
@article{Colman2012,
  author = {Colman, A and Sinton, J M and White, S M and McClinton, J T and Bowles, J A and Rubin, K H and Behn, M D and Cushman, B and Eason, D E and Gregg, T K P and Grönvold, Karl and Hidalgo, S and Howell, J and Neill, O and Russo, Chris},
  title = {Effects of variable magma supply on mid-ocean ridge eruptions: Constraints from mapped lava flow fields along the Galápagos Spreading Center},
  journal = {Geochemistry, Geophysics, Geosystems},
  year = {2012},
  volume = {13},
  number = {8},
  pages = {Q08014},
  url = {http://dx.doi.org/10.1029/2012GC004163},
  doi = {10.1029/2012GC004163}
}
Connelly DP, Copley JT, Murton BJ, Stansfield K, Tyler PA, German CR, Van Dover CL, Amon D, Furlong M, Grindlay N, Hayman N, Huehnerbach V, Judge M, Le Bas T, McPhail S, Meier A, Nakamura KI, Nye V, Pebody M, Pedersen RB, Plouviez S, Sands C, Searle RC, Stevenson P, Taws S and Wilcox S (2012), "Hydrothermal vent fields and chemosynthetic biota on the world's deepest seafloor spreading centre", Nature Communications., jan, 2012. Vol. 3, pp. 620.
Abstract: The Mid-Cayman spreading centre is an ultraslow-spreading ridge in the Caribbean Sea. Its extreme depth and geographic isolation from other mid-ocean ridges offer insights into the effects of pressure on hydrothermal venting, and the biogeography of vent fauna. Here we report the discovery of two hydrothermal vent fields on the Mid-Cayman spreading centre. The Von Damm Vent Field is located on the upper slopes of an oceanic core complex at a depth of 2,300 m. High-temperature venting in this off-axis setting suggests that the global incidence of vent fields may be underestimated. At a depth of 4,960 m on the Mid-Cayman spreading centre axis, the Beebe Vent Field emits copper-enriched fluids and a buoyant plume that rises 1,100 m, consistent with textgreater400 degrees C venting from the world's deepest known hydrothermal system. At both sites, a new morphospecies of alvinocaridid shrimp dominates faunal assemblages, which exhibit similarities to those of Mid-Atlantic vents.
BibTeX:
@article{Connelly2012,
  author = {Connelly, D P and Copley, J T and Murton, B J and Stansfield, K and Tyler, P A and German, C R and Van Dover, C L and Amon, D and Furlong, M and Grindlay, N and Hayman, N and Huehnerbach, V and Judge, M and Le Bas, Tim and McPhail, S and Meier, A and Nakamura, K I and Nye, Verity and Pebody, M and Pedersen, R B and Plouviez, S and Sands, Carla and Searle, R C and Stevenson, P and Taws, Sarah and Wilcox, S},
  title = {Hydrothermal vent fields and chemosynthetic biota on the world's deepest seafloor spreading centre},
  journal = {Nature Communications},
  year = {2012},
  volume = {3},
  pages = {620},
  doi = {10.1038/ncomms1636}
}
Corbari L, Durand L, Cambon-Bonavita MA, Gaill F and Compère P (2012), "New digestive symbiosis in the hydrothermal vent amphipoda Ventiella sulfuris", Comptes Rendus Biologies. Vol. 335(2), pp. 142-154.
Abstract: Ventiella sulfuris Barnard and Ingram, 1990 is the most abundant amphipod species inhabiting the Eastern Pacific Rise (EPR 9°N) vent fields. This vent-endemic species is frequently encountered near colonies of Pompeii worms Alvinella pompejana. V. sulfuris specimens were collected during the oceanographic cruise LADDER II at the Bio9 (9°50.3′ N, 2508 m depth) hydrothermal vent site. Main objectives were to highlight the occurrence of bacterial symbiosis in V. sulfuris and to hypothesise their implications in nutrition. Observations in light and electron microscopy (SEM, TEM) showed that the outer body surface and appendages are free of microorganisms. In contrast, the digestive system revealed two major microbial communities settled in the midgut and in the hindgut. Gut contents showed bacterial traces together with abundant fragments of Alvinellid cuticle and setae, from A. pompejana, suggesting that V. sulfuris could directly feed on Alvinellids and/or on their bacterial epibionts. Molecular analyses based on the 16S rRNA genes revealed the diversity of bacterial communities in the digestive system, of which, the Epsilonproteobacteria phylum, could be considered as one of the major bacterial group. Hypotheses were proposed on their symbiotic features and their implications in V. sulfuris nutrition.
BibTeX:
@article{Corbari2012,
  author = {Corbari, L and Durand, L and Cambon-Bonavita, M -A and Gaill, F and Compère, P},
  title = {New digestive symbiosis in the hydrothermal vent amphipoda Ventiella sulfuris},
  journal = {Comptes Rendus Biologies},
  year = {2012},
  volume = {335},
  number = {2},
  pages = {142--154},
  url = {http://dx.doi.org/10.1016/j.crvi.2011.12.005},
  doi = {10.1016/j.crvi.2011.12.005}
}
Cowen JP, Copson DA, Jolly J, Hsieh CC, Lin HT, Glazer BT and Wheat CG (2012), "Advanced instrument system for real-time and time-series microbial geochemical sampling of the deep (basaltic) crustal biosphere", Deep-Sea Research. Part I: Oceanographic Research Papers. Vol. 61(0), pp. 43-56.
Abstract: Integrated Ocean Drilling Program borehole CORK (Circulation Obviation Retrofit Kit) observatories provide long-term access to hydrothermal fluids circulating within the basaltic crust (basement), providing invaluable opportunities to study the deep biosphere. We describe the design and application parameters of the GeoMICROBE instrumented sled, an autonomous sensor and fluid sampling system. The GeoMICROBE system couples with CORK fluid delivery lines to draw large volumes of fluids from crustal aquifers to the seafloor. These fluids pass a series of in-line sensors and an in situ filtration and collection system. GeoMICROBE's major components include a primary valve manifold system, a positive displacement primary pump, sensors (e.g., fluid flow rate, temperature, dissolved O2, electrochemistry-voltammetry analyzer), a 48-port in situ filtration and fluid collection system, computerized controller, seven 24 V–40 A batteries and wet-mateable (ODI) communications with submersibles. This constantly evolving system has been successfully connected to IODP Hole 1301A on the eastern flank of the Juan de Fuca Ridge. Also described here is a mobile pumping system (MPS), which possesses many of the same components as the GeoMICROBE (e.g., pump, sensors, controller), but is directly powered and controlled in real time via submersible operations; the MPS has been employed repeatedly to collect pristine basement fluids for a variety of geochemical and microbial studies.
BibTeX:
@article{Cowen2012,
  author = {Cowen, J P and Copson, D A and Jolly, J and Hsieh, C -C and Lin, H -T and Glazer, B T and Wheat, C G},
  title = {Advanced instrument system for real-time and time-series microbial geochemical sampling of the deep (basaltic) crustal biosphere},
  journal = {Deep-Sea Research. Part I: Oceanographic Research Papers},
  year = {2012},
  volume = {61},
  number = {0},
  pages = {43--56},
  url = {http://dx.doi.org/10.1016/j.dsr.2011.11.004},
  doi = {10.1016/j.dsr.2011.11.004}
}
Dziak RP, Haxel JH, Bohnenstiehl DR, Chadwick WW, Nooner SL, Fowler MJ, Matsumoto H and Butterfield DA (2012), "Seismic precursors and magma ascent before the April 2011 eruption at Axial Seamount", Nature Geoscience. NEW YORK; 75 VARICK ST, 9TH FLR, NEW YORK, NY 10013-1917 USA, jul, 2012. Vol. 5(7), pp. 478-482. NATURE PUBLISHING GROUP.
Abstract: Volcanoes at spreading centres on land often exhibit seismicity and ground inflation months to years before an eruption, caused by a gradual influx of magma to the source reservoir1, 2, 3, 4. Deflation and seismicity can occur on time scales of hours to days, and result from the injection of magma into adjacent rift zones5, 6, 7, 8. Volcanoes at submarine rift zones, such as Axial Seamount in the northeast Pacific Ocean, have exhibited similar behaviour9, 10, 11, 12, but a direct link between seismicity, seafloor deformation and magma intrusion has never been demonstrated. Here we present recordings from ocean-bottom hydrophones and an established array of bottom-pressure recorders that reveal patterns of both microearthquakes and seafloor deformation at Axial Seamount on the Juan de Fuca Ridge, before it erupted in April 2011. Our observations show that the rate of seismicity increased steadily during a period of several years, leading up to an intrusion and eruption of magma that began on 6 April 2011. We also detected a sudden increase in seismo-acoustic energy about 2.6 h before the eruption began. Our data indicate that access to real-time seismic data, projected to be available in the near future, might facilitate short-term forecasting and provide sufficient lead-time to prepare in situ instrumentation before future intrusion and eruption events.
BibTeX:
@article{Dziak2012,
  author = {Dziak, R P and Haxel, J H and Bohnenstiehl, D R and Chadwick, W W and Nooner, S L and Fowler, M J and Matsumoto, H and Butterfield, D A},
  title = {Seismic precursors and magma ascent before the April 2011 eruption at Axial Seamount},
  journal = {Nature Geoscience},
  publisher = {NATURE PUBLISHING GROUP},
  year = {2012},
  volume = {5},
  number = {7},
  pages = {478--482},
  doi = {10.1038/ngeo1490}
}
Dziak RP, Baker ET, Shaw AM, Bohnenstiehl DR, Chadwick WW, Haxel JH, Matsumoto H and Walker SL (2012), "Flux measurements of explosive degassing using a yearlong hydroacoustic record at an erupting submarine volcano", Geochemistry, Geophysics, Geosystems., nov, 2012. Vol. 13(11), pp. Q0AF07.
Abstract: The output of gas and tephra from volcanoes is an inherently disorganized process that makes reliable flux estimates challenging to obtain. Continuous monitoring of gas flux has been achieved in only a few instances at subaerial volcanoes, but never for submarine volcanoes. Here we use the first sustained (yearlong) hydroacoustic monitoring of an erupting submarine volcano (NW Rota-1, Mariana arc) to make calculations of explosive gas flux from a volcano into the ocean. Bursts of Strombolian explosive degassing at the volcano summit (520 m deep) occurred at 1–2 min intervals during the entire 12-month hydrophone record and commonly exhibited cyclic step-function changes between high and low intensity. Total gas flux calculated from the hydroacoustic record is 5.4 ± 0.6 Tg a−1, where the magmatic gases driving eruptions at NW Rota-1 are primarily H2O, SO2, and CO2. Instantaneous fluxes varied by a factor of ∼100 over the deployment. Using melt inclusion information to estimate the concentration of CO2 in the explosive gases as 6.9 ± 0.7 wt %, we calculate an annual CO2 eruption flux of 0.4 ± 0.1 Tg a−1. This result is within the range of measured CO2 fluxes at continuously erupting subaerial volcanoes, and represents ∼0.2–0.6% of the annual estimated output of CO2from all subaerial arc volcanoes, and ∼0.4–0.6% of the mid-ocean ridge flux. The multiyear eruptive history of NW Rota-1 demonstrates that submarine volcanoes can be significant and sustained sources of CO2 to the shallow ocean.
BibTeX:
@article{Dziak2012a,
  author = {Dziak, R P and Baker, E T and Shaw, A M and Bohnenstiehl, D R and Chadwick, W W and Haxel, J H and Matsumoto, H and Walker, S L},
  title = {Flux measurements of explosive degassing using a yearlong hydroacoustic record at an erupting submarine volcano},
  journal = {Geochemistry, Geophysics, Geosystems},
  year = {2012},
  volume = {13},
  number = {11},
  pages = {Q0AF07},
  doi = {10.1029/2012GC004211}
}
Fornari DJ, Von Damm KL, Bryce JG, Cowen JP, Ferrini V, Fundis A, Lilley MD, Luther GW, Mullineaux LS, Perfit MR, Meana-Prado MF, Rubin KH, Seyfried WE, Shank TM, Soule SA, Tolstoy M and White SM (2012), "The East Pacific Rise Between 9 degrees N and 10 degrees N: Twenty-Five Years of Integrated, Multidisciplinary Oceanic Spreading Center Studies", Oceanography. ROCKVILLE; P.O. BOX 1931, ROCKVILLE, MD USA, mar, 2012. Vol. 25(1), pp. 18-43. OCEANOGRAPHY SOC.
Abstract: The East Pacific Rise from ˜ 9–10°N is an archetype for a fast-spreading mid-ocean ridge. In particular, the segment near 9°50'N has been the focus of multidisciplinary research for over two decades, making it one of the best-studied areas of the global ridge system. It is also one of only two sites along the global ridge where two historical volcanic eruptions have been observed. This volcanically active segment has thus offered unparalleled opportunities to investigate a range of complex interactions among magmatic, volcanic, hydrothermal, and biological processes associated with crustal accretion over a full magmatic cycle. At this 9°50'N site, comprehensive physical oceanographic measurements and modeling have also shed light on linkages between hydrodynamic transport of larvae and other materials and biological dynamics influenced by magmatic processes. Integrated results of high-resolution mapping, and both in situ and laboratory-based geophysical, oceanographic, geochemical, and biological observations and sampling, reveal how magmatic events perturb the hydrothermal system and the biological communities it hosts.
BibTeX:
@article{Fornari2012,
  author = {Fornari, D J and Von Damm, K L and Bryce, Julia G and Cowen, J P and Ferrini, Vicki and Fundis, A and Lilley, M D and Luther, G W and Mullineaux, L S and Perfit, M R and Meana-Prado, M F and Rubin, K H and Seyfried, W E and Shank, T M and Soule, S A and Tolstoy, M and White, S M},
  title = {The East Pacific Rise Between 9 degrees N and 10 degrees N: Twenty-Five Years of Integrated, Multidisciplinary Oceanic Spreading Center Studies},
  journal = {Oceanography},
  publisher = {OCEANOGRAPHY SOC},
  year = {2012},
  volume = {25},
  number = {1},
  pages = {18--43},
  doi = {10.5670/oceanog.2012.02}
}
Gaudron SM, Lefebvre S, Jorge AN, Gaill F and Pradillon F (2012), "Spatial And Temporal Variations In Food Web Structure From Newly-Opened Habitat At Hydrothermal Vents", Marine Environmental Research. Vol. 77, pp. 129-140.
Abstract: To highlight the spatio-temporal variability of the food web structure of hydrothermal vent fauna from newly-opened habitat, a series of Titanium Ring for Alvinellid Colonization devices (TRACs) was deployed at TICA site on the East Pacific Rise in 2006. This experiment was conducted for periods of 4 days, 13 days and one month and deployments were aligned along a gradient from the basaltic bottom to the vent openings. δ13C values of colonists revealed a narrower range of carbon sources in proximity to vent openings in Alvinella pompejana habitat than in Tevnia jerichonana habitat, separated by a distance of four meters. This was possibly due to a spatial change in available food sources with a possible higher contribution of particulate organic matter (POM) to the siboglinid habitat compared to a higher contribution of microbial primary producers such as Epsilonproteobacteria in the alvinellid habitat. Temporal variability was also observed during experimentation in the form of a shift in either δ13C and/or δ15N values for A. pompejana, Lepetodrilus elevatus, dirivultid copepods and polynoid polychaetes within a one-month window showing first of all, fast tissues turnover and secondly, a possible switch in feeding strategy or food sources. Lepidonotopodium riftense and Branchinotogluma sandersi may have to alternate between detritivorous and predatory feeding strategies. In addition, through the analysis of stable isotope composition of A. pompejana and its episymbionts, we provided evidence that these attached bacteria formed part of the worms' diet during the course of these colonization experiments.
BibTeX:
@article{Gaudron2012,
  author = {Gaudron, S M and Lefebvre, S and Jorge, A N and Gaill, F and Pradillon, F},
  title = {Spatial And Temporal Variations In Food Web Structure From Newly-Opened Habitat At Hydrothermal Vents},
  journal = {Marine Environmental Research},
  year = {2012},
  volume = {77},
  pages = {129--140},
  url = {http://dx.doi.org/10.1016/j.marenvres.2012.03.005},
  doi = {10.1016/j.marenvres.2012.03.005}
}
Guilini K, Levin LA and Vanreusel A (2012), "Cold seep and oxygen minimum zone associated sources of margin heterogeneity affect benthic assemblages, diversity and nutrition at the Cascadian margin (NE Pacific Ocean)", Progress in Oceanography. Vol. 96(0), pp. 77-92.
Abstract: Hydrate Ridge (HR), located on the northeastern Pacific margin off Oregon, is characterized by the presence of outcropping hydrates and active methane seepage. Additionally, permanent low oxygen conditions overlay the benthic realm. This study evaluated the relative influence of both seepage and oxygen minima as sources of habitat heterogeneity and potential stress-inducing features on the bathyal metazoan benthos (primarily nematodes) at three different seep and non-seep HR locations, exposed to decreasing bottom-water oxygen concentrations with increasing water depth. The nematode seep communities at HR exhibited low diversity with dominance of only one or two genera (Daptonema and Metadesmolaimus), elevated average individual biomass and δ13C evidence for strong dependance on chemosynthesis-derived carbon, resembling deep-sea seeps worldwide. Although the HR seep habitats harbored a distinct nematode community like in other known seep communities, they differed from deep-sea seeps in well-oxygenated waters based on that they shared the dominant genera with the surrounding non-seep sediments overlain by oxygen-deficient bottom water. The homogenizing effect of the oxygen minimum zone on the seep nematode assemblages and surrounding sediments was constant with increasing water depth and concomitant greater oxygen-deficiency, resulting in a loss of habitat heterogeneity.
BibTeX:
@article{Guilini2012,
  author = {Guilini, K and Levin, L A and Vanreusel, A},
  title = {Cold seep and oxygen minimum zone associated sources of margin heterogeneity affect benthic assemblages, diversity and nutrition at the Cascadian margin (NE Pacific Ocean)},
  journal = {Progress in Oceanography},
  year = {2012},
  volume = {96},
  number = {0},
  pages = {77--92},
  url = {http://dx.doi.org/10.1016/j.pocean.2011.10.003},
  doi = {10.1016/j.pocean.2011.10.003}
}
Flores GE, Wagner ID, Liu Y and Reysenbach A-L (2012), "Distribution, abundance, and diversity patterns of the thermoacidophilic ``deep-sea hydrothermal vent euryarchaeota 2''", FRONTIERS IN MICROBIOLOGY. Vol. 3
Abstract: Cultivation-independent studies have shown that taxa belonging to the ``deep-sea hydrothermal vent euryarchaeota 2'' (DHVE2) lineage are widespread at deep-sea hydrothermal vents. While this lineage appears to be a common and important member of the microbial community at vent environments, relatively little is known about their overall distribution and phylogenetic diversity. In this study, we examined the distribution, relative abundance, co-occurrence patterns, and phylogenetic diversity of cultivable thermoacidophilic DHVE2 in deposits from globally distributed vent fields. Results of quantitative polymerase chain reaction assays with primers specific for the DHVE2 and Archaea demonstrate the ubiquity of the DHVE2 at deep-sea vents and suggest that they are significant members of the archaeal communities of established vent deposit communities. Local similarity analysis of pyrosequencing data revealed that the distribution of the DHVE2 was positively correlated with 10 other Euryarchaeota phylotypes and negatively correlated with mostly Crenarchaeota phylotypes. Targeted cultivation efforts resulted in the isolation of 12 axenic strains from six different vent fields, expanding the cultivable diversity of this lineage to vents along the East Pacific Rise and Mid-Atlantic Ridge. Eleven of these isolates shared greater than 97% 16S rRNA gene sequence similarity with one another and the only described isolate of the DHVE2, Aciduliprofundum boonei T469(T). Sequencing and phylogenetic analysis of five protein-coding loci, atpA, EF-2, radA, rpoB, and secY, revealed clustering of isolates according to geographic region of isolation. Overall, this study increases our understanding of the distribution, abundance, and phylogenetic diversity of the DHVE2.
BibTeX:
@article{ISI:000208863600101,
  author = {Flores, Gilberto E and Wagner, Isaac D and Liu, Yitai and Reysenbach, Anna-Louise},
  title = {Distribution, abundance, and diversity patterns of the thermoacidophilic ``deep-sea hydrothermal vent euryarchaeota 2''},
  journal = {FRONTIERS IN MICROBIOLOGY},
  year = {2012},
  volume = {3},
  doi = {10.3389/fmicb.2012.00047}
}
Nigro LM, Harris K, Orcutt BN, Hyde A, Clayton-Luce S, Becker K and Teske A (2012), "Microbial communities at the borehole observatory on the Costa Rica Rift flank (Ocean Drilling Program Hole 896A)", FRONTIERS IN MICROBIOLOGY. Vol. 3
Abstract: The microbiology of subsurface, hydrothermally influenced basaltic crust
flanking midocean ridges has remained understudied, due to the
difficulty in accessing the subsurface environment. The instrumented
boreholes resulting from scientific ocean drilling offer access to
samples of the formation fluids circulating through oceanic crust. We
analyzed the phylogenetic diversity of bacterial communities of fluid
and microbial mat samples collected in situ from the observatory at
Ocean Drilling Program Hole 896A, drilled into similar to 6.5
million-year-old basaltic crust on the flank of the Costa Rica Rift in
the equatorial Pacific Ocean. Bacterial 16S rRNA gene sequences
recovered from borehole fluid and from a microbial mat coating the outer
surface of the fluid port revealed both unique and shared phylotypes.
The dominant bacterial clones from both samples were related to the
autotrophic, sulfur-oxidizing genus Thiomicrospira. Both samples yielded
diverse gamma- and alphaproteobacterial phylotypes, as well as members
of the Bacteroidetes, Planctomycetes, and Verrucomicrobia. Analysis of
ribulose-1,5-bisphosphate carboxylase/oxygenase (RuBisCO) genes (cbbL
and cbbM) from the sampling port mat and from the borehole fluid
demonstrated autotrophic carbon assimilation potential for in situ
microbial communities; most cbbL genes were related to those of the
sulfur-oxidizing genera Thioalkalivibrio and Thiomicrospira, and cbbM
genes were affiliated with uncultured phylotypes from hydrothermal vent
plumes and marine sediments. Several 16S rRNA gene phylotypes from the
896A observatory grouped with phylotypes recovered from seawater-exposed
basalts and sulfide deposits at inactive hydrothermal vents, but there
is little overlap with hydrothermally influenced basaltic boreholes
1026B and U1301A on the Juan de Fuca Ridge flank, suggesting that
site-specific characteristics of Hole 896A (i.e., seawater mixing into
borehole fluids) affect the microbial community composition.
BibTeX:
@article{ISI:000208863600280,
  author = {Nigro, Lisa M and Harris, Kate and Orcutt, Beth N and Hyde, Andrew and Clayton-Luce, Samuel and Becker, Keir and Teske, Andreas},
  title = {Microbial communities at the borehole observatory on the Costa Rica Rift flank (Ocean Drilling Program Hole 896A)},
  journal = {FRONTIERS IN MICROBIOLOGY},
  year = {2012},
  volume = {3},
  doi = {10.3389/fmicb.2012.00232}
}
Bowles MW, Nigro LM, Teske AP and Joye SB (2012), "Denitrification and environmental factors influencing nitrate removal in Guaymas Basin hydrothermally altered sediments", FRONTIERS IN MICROBIOLOGY. Vol. 3
Abstract: We measured potential nitrate removal and denitrification rates in
hydrothermally altered sediments inhabited by Beggiatoa mats and
adjacent brown oil stained sediments from the Guaymas Basin, Gulf of
California. Sediments with Beggiatoa maintained slightly higher rates of
potential denitrification than did brown sediments at 31.2 +/- 12.1
versus 21.9 +/- 1.4 mu M N day-1, respectively. In contrast, the nitrate
removal rates in brown sediments were higher than those observed in
mat-hosting sediments at 418 +/- 145 versus 174 +/- 74 mu M N day-1,
respectively. Additional experiments were conducted to assess the
responses of denitrifying communities to environmental factors [i.e.,
nitrate, sulfide, and dissolved organic carbon (DOC) concentration)].
The denitrifying community had a high affinity for nitrate (Km = 137 +/-
91 mu M N day-1), in comparison to other environmental communities of
denitrifiers, and was capable of high maximum rates of denitrification
(Vmax = 1164 +/- 153 mu M N day-1). The presence of sulfide resulted in
significantly lower denitrification rates. Microorganisms with the
potential to perform denitrification were assessed in these sediments
using the bacterial 16S rRNA gene and nitrous oxide reductase (nosZ)
functional gene libraries. The bacterial 16S rRNA gene clone library was
dominated by Epsilonproteobacteria (38%), some of which (e.g.,
Sulfurimonas sp.) have a potential for sulfide-dependent
denitrification. The nosZ clone library did not contain clones similar
to pure culture denitrifiers; these clones were most closely associated
with environmental clones.
BibTeX:
@article{ISI:000208863600378,
  author = {Bowles, Marshall W and Nigro, Lisa M and Teske, Andreas P and Joye, Samantha B},
  title = {Denitrification and environmental factors influencing nitrate removal in Guaymas Basin hydrothermally altered sediments},
  journal = {FRONTIERS IN MICROBIOLOGY},
  year = {2012},
  volume = {3},
  doi = {10.3389/fmicb.2012.00377}
}
Scott KM, Boller AJ, Dobrinski KP and Le Bris N (2012), "Response of hydrothermal vent vestimentiferan Riftia pachyptila to differences in habitat chemistry", MARINE BIOLOGY., feb, 2012. Vol. 159(2), pp. 435-442.
Abstract: Vestimentiferan tubeworms, which rely on intracellular sulfide-oxidizing
autotrophic bacteria for organic carbon, flourish at deep-sea
hydrothermal vents despite the erratic nature of their habitat. To
assess the degree to which differences in habitat chemistry (sulfide,
pH/CO(2)) might impact host and symbiont metabolic activity, Riftia
pachyptila tubeworms were collected from habitats with low (H(2)S textless
0.0001 mM) and high (up to 0.7 mM) sulfide concentrations. The elemental
sulfur content of the symbiont-containing trophosome organ was lower in
specimens collected from the low-sulfide site. Symbiont abundance,
RubisCO activity, and trophosome carbon fixation rates were not
significantly different for individuals collected from low- versus
high-sulfide habitats. Carbonic anhydrase activities were higher in the
anterior gas exchange organs of R. pachyptila from the low-sulfide
habitat. Despite large differences in habitat chemistry, symbiont
abundance and autotrophic potential were consistent, while the host
appears to tailor carbonic anhydrase activity to environmental CO(2)
availability.
BibTeX:
@article{ISI:000299199000017,
  author = {Scott, Kathleen M and Boller, Amanda J and Dobrinski, Kimberly P and Le Bris, Nadine},
  title = {Response of hydrothermal vent vestimentiferan Riftia pachyptila to differences in habitat chemistry},
  journal = {MARINE BIOLOGY},
  year = {2012},
  volume = {159},
  number = {2},
  pages = {435--442},
  doi = {10.1007/s00227-011-1821-5}
}
Voight JR (2012), "Meristic variation in males of the hydrothermal vent octopus, Muusoctopus hydrothermalis (Cephalopoda: Octopodidae)", JOURNAL OF THE MARINE BIOLOGICAL ASSOCIATION OF THE UNITED KINGDOM., mar, 2012. Vol. 92(2), pp. 361-366.
Abstract: Intraspecific variation in characters such as arm sucker and gill
lamellae counts in octopodids is yet to be thoroughly investigated,
potentially hampering our ability to recognize species. In this study,
data from 13 specimens of Muusoctopus hydrothermalis collected at four
hydrothermal vents on the East Pacific Rise between 8 degrees 38'N and
12 degrees 48'N are considered. Although the northern and southern
octopuses differ minimally in size, mean sucker count by arm in the
northern group is 11.7 to 22.8% higher than it is in the southern
group; in addition these octopuses typically have an additional gill
lamella and bulkier funnel organs. The arms of each individual carry a
different number of suckers. The difference is significant on
nonadjacent arms, a pattern that merits examination in a broader
taxonomic context. Why these differences exist among conspecifics
remains unknown, the incidence of parasitic copepods is not different
between the groups and the between-group variation in arm suckers seen
here compares well with a previous report of variation among 18
specimens from the type locality. Increases in meristic characters
(counts) in fish are attributed to lower temperatures during embryonic
development following Jordan's rule. Northern and southern vents offer
the octopuses a wide temperature range, but vent fluid chemistry
differs. Northern vent fluids may be more toxic; if so, developing
octopus embryos may survive only minimal vent fluid exposure and
therefore develop at low temperatures. At the less toxic southern vents,
eggs may survive greater exposure to vent fluids and thus develop at
higher temperatures.
BibTeX:
@article{ISI:000299931800014,
  author = {Voight, Janet R},
  title = {Meristic variation in males of the hydrothermal vent octopus, Muusoctopus hydrothermalis (Cephalopoda: Octopodidae)},
  journal = {JOURNAL OF THE MARINE BIOLOGICAL ASSOCIATION OF THE UNITED KINGDOM},
  year = {2012},
  volume = {92},
  number = {2},
  pages = {361--366},
  doi = {10.1017/S0025315411000993}
}
Bourbonnais A, Lehmann MF, Butterfield DA and Juniper SK (2012), "Subseafloor nitrogen transformations in diffuse hydrothermal vent fluids of the Juan de Fuca Ridge evidenced by the isotopic composition of nitrate and ammonium", GEOCHEMISTRY GEOPHYSICS GEOSYSTEMS., feb, 2012. Vol. 13
Abstract: Little is known about dissolved inorganic nitrogen (DIN) transformations in hydrothermal vent (HV) fluids. Here, we present the first isotopic measurements of nitrate (delta N-15 and delta O-18) and ammonium (delta N-15) from three HV fields on the Juan de Fuca ridge (NE-Pacific). The dominant process that drives DIN concentration variations in low-T diffuse fluids is water mass mixing below the seafloor, with no effect on the DIN isotope ratios. Strong inter-site variations in the concentration and delta N-15 of NH4+ in high-T fluids suggest different subsurface nitrogen (N) sources (deep-sea nitrate versus organic sediments) for hydrothermally discharged ammonium. Low NH4+ community N isotope effects (textless3 parts per thousand) for net NH4+ consumption suggest an important contribution from gross ammonium regeneration in low-T fluids. Elevation of HV nitrate N-15/N-14 and O-18/O-16 over deep-sea mean isotope values at some sites, concomitant with decreased nitrate concentrations, indicate assimilatory or dissimilatory nitrate consumption by bacteria in the subsurface, with relatively low community N isotope effects ((15)epsilon(k) textless 3 parts per thousand). The low N isotope effects suggest that nitrate assimilation or denitrification occur in bacterial mats, and/or in situ production of low delta N-15 nitrate. A significantly stronger relative increase for nitrate delta O-18 than for delta N-15 was observed at many sites, resulting in marked deviations from the 1:1 relationship for nitrate delta N-15 versus delta O-18 that is expected for nitrate reduction in marine settings. Simple box-model calculation show that the observed un-coupling of N and O nitrate isotope ratios is consistent with nitrate regeneration by either nitrite reoxidation and/or partial nitrification of hydrothermal ammonium (possibly originating from N-2 fixation). Our isotope data confirm the role of subsurface microbial communities in modulating hydrothermal fluxes to the deep ocean.
BibTeX:
@article{ISI:000299990700001,
  author = {Bourbonnais, Annie and Lehmann, Moritz F and Butterfield, David A and Juniper, S Kim},
  title = {Subseafloor nitrogen transformations in diffuse hydrothermal vent fluids of the Juan de Fuca Ridge evidenced by the isotopic composition of nitrate and ammonium},
  journal = {GEOCHEMISTRY GEOPHYSICS GEOSYSTEMS},
  year = {2012},
  volume = {13},
  doi = {10.1029/2011GC003863}
}
Hautala S, Johnson HP, Pruis M, Garcia-Berdeal I and Bjorklund T (2012), "Low-Temperature Hydrothermal Plumes in the Near-Bottom Boundary Layer at Endeavour Segment, Juan de Fuca Ridge", OCEANOGRAPHY., mar, 2012. Vol. 25(1, SI), pp. 192-195.
BibTeX:
@article{ISI:000301095200020,
  author = {Hautala, Susan and Johnson, H Paul and Pruis, Matthew and Garcia-Berdeal, Irene and Bjorklund, Tor},
  title = {Low-Temperature Hydrothermal Plumes in the Near-Bottom Boundary Layer at Endeavour Segment, Juan de Fuca Ridge},
  journal = {OCEANOGRAPHY},
  year = {2012},
  volume = {25},
  number = {1, SI},
  pages = {192--195}
}
Girguis PR and Holden JF (2012), "On the Potential for Bioenergy and Biofuels from Hydrothermal Vent Microbes", OCEANOGRAPHY., mar, 2012. Vol. 25(1, SI), pp. 213-217.
BibTeX:
@article{ISI:000301095200023,
  author = {Girguis, Peter R and Holden, James F},
  title = {On the Potential for Bioenergy and Biofuels from Hydrothermal Vent Microbes},
  journal = {OCEANOGRAPHY},
  year = {2012},
  volume = {25},
  number = {1, SI},
  pages = {213--217}
}
Gardebrecht A, Markert S, Sievert SM, Felbeck H, Thuermer A, Albrecht D, Wollherr A, Kabisch J, Le Bris N, Lehmann R, Daniel R, Liesegang H, Hecker M and Schweder T (2012), "Physiological homogeneity among the endosymbionts of Riftia pachyptila and Tevnia jerichonana revealed by proteogenomics", ISME JOURNAL., apr, 2012. Vol. 6(4), pp. 766-776.
Abstract: The two closely related deep-sea tubeworms Riftia pachyptila and Tevnia
jerichonana both rely exclusively on a single species of
sulfide-oxidizing endosymbiotic bacteria for their nutrition. They do,
however, thrive in markedly different geochemical conditions. A detailed
proteogenomic comparison of the endosymbionts coupled with an in situ
characterization of the geochemical environment was performed to
investigate their roles and expression profiles in the two respective
hosts. The metagenomes indicated that the endosymbionts are
genotypically highly homogeneous. Gene sequences coding for enzymes of
selected key metabolic functions were found to be 99.9% identical. On
the proteomic level, the symbionts showed very consistent metabolic
profiles, despite distinctly different geochemical conditions at the
plume level of the respective hosts. Only a few minor variations were
observed in the expression of symbiont enzymes involved in sulfur
metabolism, carbon fixation and in the response to oxidative stress.
Although these changes correspond to the prevailing environmental
situation experienced by each host, our data strongly suggest that the
two tubeworm species are able to effectively attenuate differences in
habitat conditions, and thus to provide their symbionts with similar
micro-environments. The ISME Journal (2012) 6, 766-776; doi:
10.1038/ismej.2011.137; published online 20 October 2011
BibTeX:
@article{ISI:000301945500007,
  author = {Gardebrecht, Antje and Markert, Stephanie and Sievert, Stefan M and Felbeck, Horst and Thuermer, Andrea and Albrecht, Dirk and Wollherr, Antje and Kabisch, Johannes and Le Bris, Nadine and Lehmann, Ruediger and Daniel, Rolf and Liesegang, Heiko and Hecker, Michael and Schweder, Thomas},
  title = {Physiological homogeneity among the endosymbionts of Riftia pachyptila and Tevnia jerichonana revealed by proteogenomics},
  journal = {ISME JOURNAL},
  year = {2012},
  volume = {6},
  number = {4},
  pages = {766--776},
  doi = {10.1038/ismej.2011.137}
}
Biddle JF, Cardman Z, Mendlovitz H, Albert DB, Lloyd KG, Boetius A and Teske A (2012), "Anaerobic oxidation of methane at different temperature regimes in Guaymas Basin hydrothermal sediments", ISME JOURNAL., may, 2012. Vol. 6(5), pp. 1018-1031.
Abstract: Anaerobic oxidation of methane (AOM) was investigated in hydrothermal
sediments of Guaymas Basin based on delta C-13 signatures of CH4,
dissolved inorganic carbon and porewater concentration profiles of CH4
and sulfate. Cool, warm and hot in-situ temperature regimes (15-20
degrees C, 30-35 degrees C and 70-95 degrees C) were selected from
hydrothermal locations in Guaymas Basin to compare AOM geochemistry and
16S ribosomal RNA (rRNA), mcrA and dsrAB genes of the microbial
communities. 16S rRNA gene clone libraries from the cool and hot AOM
cores yielded similar archaeal types such as Miscellaneous
Crenarchaeotal Group, Thermoproteales and anaerobic methane-oxidizing
archaea (ANME)-1; some of the ANME-1 archaea formed a separate 16S rRNA
lineage that at present seems to be limited to Guaymas Basin. Congruent
results were obtained by mcrA gene analysis. The warm AOM core,
chemically distinct by lower porewater sulfide concentrations, hosted a
different archaeal community dominated by the two deep subsurface
archaeal lineages Marine Benthic Group D and Marine Benthic Group B, and
by members of the Methanosarcinales including ANME-2 archaea. This
distinct composition of the methane-cycling archaeal community in the
warm AOM core was confirmed by mcrA gene analysis. Functional genes of
sulfate-reducing bacteria and archaea, dsrAB, showed more overlap
between all cores, regardless of the core temperature. 16S rRNA gene
clone libraries with Euryarchaeota-specific primers detected members of
the Archaeoglobus clade in the cool and hot cores. A V6-tag
high-throughput sequencing survey generally supported the clone library
results while providing high-resolution detail on archaeal and bacterial
community structure. These results indicate that AOM and the responsible
archaeal communities persist over a wide temperature range. The ISME
Journal (2012) 6, 1018-1031; doi:10.1038/ismej.2011.164; published
online 17 November 2011
BibTeX:
@article{ISI:000302950700011,
  author = {Biddle, Jennifer F and Cardman, Zena and Mendlovitz, Howard and Albert, Daniel B and Lloyd, Karen G and Boetius, Antje and Teske, Andreas},
  title = {Anaerobic oxidation of methane at different temperature regimes in Guaymas Basin hydrothermal sediments},
  journal = {ISME JOURNAL},
  year = {2012},
  volume = {6},
  number = {5},
  pages = {1018--1031},
  doi = {10.1038/ismej.2011.164}
}
Kirchner TM and Gillis KM (2012), "Mineralogical and strontium isotopic record of hydrothermal processes in the lower ocean crust at and near the East Pacific Rise", CONTRIBUTIONS TO MINERALOGY AND PETROLOGY., jul, 2012. Vol. 164(1), pp. 123-141.
Abstract: Tectonic exposures of upper plutonics (textgreater 800 m) that are part of a
contiguous section of young East Pacific Rise (EPR) crust at the Hess
Deep Rift provide the first regional-scale constraints on hydrothermal
processes in the upper plutonic crust formed at a fast-spreading ridge.
Submersible-collected samples recovered over a 4-km-wide region show
that the sheeted dike complex is largely underlain by a 150- to
200-m-thick gabbro unit, followed by a more primitive gabbronorite unit.
Gabbroic samples are variably altered by pervasive fluid flow along
fracture networks to amphibole-dominated assemblages. The gabbroic rocks
are significantly less altered (average 11% hydrous phases) than the
overlying sheeted dike complex (average 24%), and the percentage of
hydrous alteration diminishes with depth. Incipient, pervasive fluid
flow occurred at amphibolite facies conditions (average 720A degrees C),
with slightly higher temperatures in the lower 500 m of the section. The
extent of subsequent lower-temperature alteration is generally low and
regionally variable. The gabbroic samples are slightly elevated in
Sr-87/Sr-86 relative to fresh rock values (0.7024) and less enriched
than the overlying sheeted dike complex. Sr-87/Sr-86 for the pervasively
altered gabbroic samples ranges from 0.70244 to 0.70273 (mean 0.70257),
tonalites is 0.7038, and pyroxene hornfels ranges from 0.70259 to
0.70271. Sr-87/Sr-86 does not vary with depth, and there is a strong
positive correlation with the percentage of hydrous phases. Strontium
contents of igneous and hydrothermal minerals, combined with bulk rock
Sr-87/Sr-86, indicate that Sr-isotopic exchange is largely controlled by
the uptake of fluid Sr-87/Sr-86 in hydrous minerals and does not require
Sr gain or loss. The minimum, time-integrated fluid-rock ratio for the
sheeted dike complex and upper plutonics is 0.55-0.66, and the fluid
flux calculated by mass balance is similar to 2.1 to 2.5 x 10(6) kg
m(-2), 30-60% higher than fluid fluxes calculated in the same manner
for sheeted dike complexes on their own at Hess and Pito Deeps, and
Ocean Drilling Program Hole 504B. Alteration patterns within the upper
plutonics evolved in response to axial magma chamber (AMC) dynamics at
the EPR, such that magma replenishment led to assimilation and thermal
metamorphism of the country rock, and the position of the hydrothermal
root-zone tracked the vertical migration of the AMC. The freshness of
the lowermost gabbroic rocks suggests that pervasive fluid flow does not
lead to significant fluid and heat fluxes at and near fast-spreading
ridges.
BibTeX:
@article{ISI:000305233800008,
  author = {Kirchner, Timo M and Gillis, Kathryn M},
  title = {Mineralogical and strontium isotopic record of hydrothermal processes in the lower ocean crust at and near the East Pacific Rise},
  journal = {CONTRIBUTIONS TO MINERALOGY AND PETROLOGY},
  year = {2012},
  volume = {164},
  number = {1},
  pages = {123--141},
  doi = {10.1007/s00410-012-0729-5}
}
Flores GE, Hunter RC, Liu Y, Mets A, Schouten S and Reysenbach A-L (2012), "Hippea jasoniae sp nov and Hippea alviniae sp nov., thermoacidophilic members of the class Deltaproteobacteria isolated from deep-sea hydrothermal vent deposits", INTERNATIONAL JOURNAL OF SYSTEMATIC AND EVOLUTIONARY MICROBIOLOGY., jun, 2012. Vol. 62(6), pp. 1252-1258.
Abstract: Thirteen novel, obligately anaerobic, thermoacidophilic bacteria were isolated from deep-sea hydrothermal vent sites. Four of the strains, designated EP5-r(T), KM1, Mar08-272r(T) and Mar08-368r, were selected for metabolic and physiological characterization. With the exception of strain EP5-r(T), all strains were short rods that grew between 40 and 72 degrees C, with optimal growth at 60-65 degrees C. Strain EP5-r(T) was more ovoid in shape and grew between 45 and 75 degrees C, with optimum growth at 60 degrees C. The pH range for growth of all the isolates was between pH 3.5 and 5.5 (optimum pH 4.5 to 5.0). Strain Mar08-272r(T) could only grow up to pH 5.0. Elemental sulfur was required for heterotrophic growth on acetate, succinate, Casamino acids and yeast extract. Strains EP5-r(T), Mar08-272r(T) and Mar08-368r could also use fumarate, while strains EP5-r(T), KM1 and Mar08-272r(T) could also use propionate. All isolates were able to grow chemolithotrophically on H-2, CO2, sulfur and vitamins. Phylogenetic analysis of 16S rRNA gene sequences placed all isolates within the family Desulfurellaceae of the class Deltaproteobacteria, with the closest cultured relative being Hippea maritima MH2T (similar to 95-98% gene sequence similarity). Phylogenetic analysis also identified several isolates with at least one intervening sequence within the 16S rRNA gene. The genomic DNA G+C contents of strains EP5-r(T), KM1, Mar08-272r(T) and Mar08-368r were 37.1, 42.0, 35.6 and 37.9 mol%, respectively. The new isolates differed most significantly from H. maritima MH2T in their phylogenetic placement and in that they were obligate thermoacidophiles. Based on these phylogenetic and phenotypic properties, the following two novel species are proposed: Hippea jasoniae sp. nov. (type strain Mar08-272r(T)=DSM 24585(T)=OCM 985(T)) and Hippea alviniae sp. nov. (type strain EP5-r(T)=DSM 24586(T)=OCM 986(T)).
BibTeX:
@article{ISI:000306502100006,
  author = {Flores, Gilberto E and Hunter, Ryan C and Liu, Yitai and Mets, Anchelique and Schouten, Stefan and Reysenbach, Anna-Louise},
  title = {Hippea jasoniae sp nov and Hippea alviniae sp nov., thermoacidophilic members of the class Deltaproteobacteria isolated from deep-sea hydrothermal vent deposits},
  journal = {INTERNATIONAL JOURNAL OF SYSTEMATIC AND EVOLUTIONARY MICROBIOLOGY},
  year = {2012},
  volume = {62},
  number = {6},
  pages = {1252--1258},
  doi = {10.1099/ijs.0.033001-0}
}
Pante E and Watling L (2012), "Chrysogorgia from the New England and Corner Seamounts: Atlantic-Pacific connections", JOURNAL OF THE MARINE BIOLOGICAL ASSOCIATION OF THE UNITED KINGDOM., aug, 2012. Vol. 92(5), pp. 911-927.
Abstract: Recent exploration of the New England and Corner Seamounts revealed four
new species of Chrysogorgia, described here using a combination of
molecular and morphological data. These four species are characterized
by a sinistral spiral, a character that, with one known exception, has
only been reported for Pacific species. In addition, two species have a
sclerite composition typical of the Pacific ('squamosae typicae'). This
faunal connection between the Atlantic and the Pacific is confirmed by
analysis of the mitochondrial msh1 gene. The exceptional preservation of
specimens collected with remotely operated vehicles allows us to discuss
the effect of growth on some morphological characters.
BibTeX:
@article{ISI:000307173100006,
  author = {Pante, Eric and Watling, Les},
  title = {Chrysogorgia from the New England and Corner Seamounts: Atlantic-Pacific connections},
  journal = {JOURNAL OF THE MARINE BIOLOGICAL ASSOCIATION OF THE UNITED KINGDOM},
  year = {2012},
  volume = {92},
  number = {5},
  pages = {911--927},
  doi = {10.1017/S0025315411001354}
}
Martin AM and Goffredi SK (2012), "`Pliocardia' krylovata, a new species of vesicomyid clam from cold seeps along the Costa Rica Margin", JOURNAL OF THE MARINE BIOLOGICAL ASSOCIATION OF THE UNITED KINGDOM., aug, 2012. Vol. 92(5), pp. 1127-1137.
Abstract: `Pliocardia' krylovata, sp. nov. (Bivalvia: Vesicomyidae: Pliocardiinae)
is described from cold seeps off the coast of the Nicoya Peninsula,
Costa Rica (700-1000 m depth). The phylogenetic position of `P.'
krylovata was assessed by both morphological comparisons as well as
nucleotide data from the cytochrome c oxidase I gene. Within the
vesicomyids, `P.' krylovata belongs to the Pliocardiinae and its closest
relative is `Calyptogena' ponderosa, which also bears some morphological
resemblance to the genus Pliocardia, perhaps suggesting a need for
reanalysis of not only its generic designation, but also the entire
Pliocardiinae subfamily. `P.' krylovata has morphological similarities
to `Pliocardia' bowdeniana and `Vesicomya' crenulomarginata, recently
reassigned to the genus Pliocardia, including a thick shell, obvious
rostrum, pointed posterior end, and a sculptured shell with concentric
ribs on the outer surface, to name a few. It is morphologically
distinguished, however, by having a complex pallial sinus and remarkably
deep escutcheon.
BibTeX:
@article{ISI:000307173100024,
  author = {Martin, Alanna M and Goffredi, Shana K},
  title = {`Pliocardia' krylovata, a new species of vesicomyid clam from cold seeps along the Costa Rica Margin},
  journal = {JOURNAL OF THE MARINE BIOLOGICAL ASSOCIATION OF THE UNITED KINGDOM},
  year = {2012},
  volume = {92},
  number = {5},
  pages = {1127--1137},
  doi = {10.1017/S0025315411000713}
}
Hendrickx ME (2012), "Squat lobsters (Crustacea: Decapoda: Galatheoidea and Chirostyloidea) collected during the TALUD XIV cruise in the Gulf of California, Mexico, and rediscovery of Gastroptychus perarmatus (Haig, 1968) in the eastern Pacific", ZOOTAXA., aug, 2012. (3418), pp. 28-40.
Abstract: Seven species of squat lobsters were collected during the TALUD XIV
cruise in the Gulf of California, Mexico. Gastroptychus perarmatus
(Haig, 1968) was collected for the second time since it was described
and represents a first record of the genus in the tropical eastern
Pacific. Its association with gorgonians is also noted from color
pictures taken during a deep-water dive in another cruise in the area.
Janetogalathea californiensis (Benedict, 1902) was captured in four
sampling stations, in the same area where it has been previously
reported. Three species of Munida Leach, 1820 were collected (M.
bapensis Hendrickx, 2000, M. mexicana Benedict, 1902, and M. tenella
Benedict, 1902). Records of M. bapensis of this cruise combined with
additional captures of this species in 2007 in the same area indicate
that it is the most abundant deep-water species of squat lobster in the
northern part of the central Gulf of California. Among the species of
Munida, M. tenella was second in abundance and included specimens much
larger than previously known. The single record for M. mexicana fits
within the currently known depth and geographical ranges. Only one
species of Munidopsis Whiteaves, 1874 (M. depressa Faxon, 1892) was
collected, in one of the deeper sampling stations visited during the
cruise and its northernmost distribution limit within the Gulf of
California is increased by ca two degrees of latitude. The seventh
species collected during this survey, Pleuroncodes planipes Stimpson,
1860, is a common inhabitant of the California Current and the Gulf of
California.
BibTeX:
@article{ISI:000307406000002,
  author = {Hendrickx, Michel E},
  title = {Squat lobsters (Crustacea: Decapoda: Galatheoidea and Chirostyloidea) collected during the TALUD XIV cruise in the Gulf of California, Mexico, and rediscovery of Gastroptychus perarmatus (Haig, 1968) in the eastern Pacific},
  journal = {ZOOTAXA},
  year = {2012},
  number = {3418},
  pages = {28--40}
}
Egas C, Pinheiro M, Gomes P, Barroso C and Bettencourt R (2012), "The Transcriptome of Bathymodiolus azoricus Gill Reveals Expression of Genes from Endosymbionts and Free-Living Deep-Sea Bacteria", MARINE DRUGS., aug, 2012. Vol. 10(8), pp. 1765-1783.
Abstract: Deep-sea environments are largely unexplored habitats where a surprising
number of species may be found in large communities, thriving regardless
of the darkness, extreme cold, and high pressure. Their unique
geochemical features result in reducing environments rich in methane and
sulfides, sustaining complex chemosynthetic ecosystems that represent
one of the most surprising findings in oceans in the last 40 years. The
deep-sea Lucky Strike hydrothermal vent field, located in the Mid
Atlantic Ridge, is home to large vent mussel communities where
Bathymodiolus azoricus represents the dominant faunal biomass, owing its
survival to symbiotic associations with methylotrophic or methanotrophic
and thiotrophic bacteria. The recent transcriptome sequencing and
analysis of gill tissues from B. azoricus revealed a number of genes of
bacterial origin, hereby analyzed to provide a functional insight into
the gill microbial community. The transcripts supported a metabolically
active microbiome and a variety of mechanisms and pathways, evidencing
also the sulfur and methane metabolisms. Taxonomic affiliation of
transcripts and 16S rRNA community profiling revealed a microbial
community dominated by thiotrophic and methanotrophic endosymbionts of
B. azoricus and the presence of a Sulfurovum-like epsilonbacterium.
BibTeX:
@article{ISI:000308207400009,
  author = {Egas, Conceicao and Pinheiro, Miguel and Gomes, Paula and Barroso, Cristina and Bettencourt, Raul},
  title = {The Transcriptome of Bathymodiolus azoricus Gill Reveals Expression of Genes from Endosymbionts and Free-Living Deep-Sea Bacteria},
  journal = {MARINE DRUGS},
  year = {2012},
  volume = {10},
  number = {8},
  pages = {1765--1783},
  doi = {10.3390/md10081765}
}
Xu G and Di Iorio D (2012), "Deep sea hydrothermal plumes and their interaction with oscillatory flows", GEOCHEMISTRY GEOPHYSICS GEOSYSTEMS., sep, 2012. Vol. 13
Abstract: The acoustic scintillation method is applied to the investigation and
monitoring of a vigorous hydrothermal plume from Dante within the Main
Endeavour vent field (MEF) in the Endeavour Ridge segment. A 40 day time
series of the plume's vertical velocity and temperature fluctuations
provides a unique opportunity to study deep sea plume dynamics in a
tidally varying horizontal cross flow. An integral plume model that
takes into account ambient stratification and horizontal cross flows is
established from the conservation equations of mass, momentum and
density deficit. Using a linear additive entrainment velocity in the
model ( E = alpha U-m + beta U-perpendicular to) that is a function of
both the plume relative axial velocity (U-m) and the relative ambient
flow perpendicular to the plume (U-perpendicular to) gives consistent
results to the experimental data, suggesting entrainment coefficients
alpha = 0.1 and beta = 0.6. Also from the integral model, the plume
height in a horizontal cross flow ( U-a) is shown to scale as
1.8B(1/3)U(a)(-1/3)N(-2/3) for 0.01 textless= U-a textless= 0.1 m/s where B is the
initial buoyancy transport and N is the ambient stratification, both of
which are assumed constant.
BibTeX:
@article{ISI:000308889800003,
  author = {Xu, Guangyu and Di Iorio, Daniela},
  title = {Deep sea hydrothermal plumes and their interaction with oscillatory flows},
  journal = {GEOCHEMISTRY GEOPHYSICS GEOSYSTEMS},
  year = {2012},
  volume = {13},
  doi = {10.1029/2012GC004188}
}
Wankel SD, Adams MM, Johnston DT, Hansel CM, Joye SB and Girguis PR (2012), "Anaerobic methane oxidation in metalliferous hydrothermal sediments: influence on carbon flux and decoupling from sulfate reduction", ENVIRONMENTAL MICROBIOLOGY., oct, 2012. Vol. 14(10, SI), pp. 2726-2740.
Abstract: The anaerobic oxidation of methane (AOM) is a globally significant sink
that regulates methane flux from sediments into the oceans and
atmosphere. Here we examine mesophilic to thermophilic AOM in
hydrothermal sediments recovered from the Middle Valley vent field, on
the Juan de Fuca Ridge. Using continuous-flow sediment bioreactors and
batch incubations, we characterized (i) the degree to which AOM
contributes to net dissolved inorganic carbon flux, (ii) AOM and sulfate
reduction (SR) rates as a function of temperature and (iii) the
distribution and density of known anaerobic methanotrophs (ANMEs). In
sediment bioreactors, inorganic carbon stable isotope mass balances
results indicated that AOM accounted for between 16% and 86% of the
inorganic carbon produced, underscoring the role of AOM in governing
inorganic carbon flux from these sediments. At 90 degrees C, AOM
occurred in the absence of SR, demonstrating a striking decoupling of
AOM from SR. An abundance of Fe(III)-bearing minerals resembling mixed
valent Fe oxides, such as green rust, suggests the potential for a
coupling of AOM to Fe(III) reduction in these metalliferous sediments.
While SR bacteria were only observed in cooler temperature sediments,
ANMEs allied to ANME-1 ribotypes, including a putative ANME-1c group,
were found across all temperature regimes and represented a substantial
proportion of the archaeal community. In concert, these results extend
and reshape our understanding of the nature of high temperature methane
biogeochemistry, providing insight into the physiology and ecology of
thermophilic anaerobic methanotrophy and suggesting that AOM may play a
central role in regulating biological dissolved inorganic carbon fluxes
to the deep ocean from the organic-poor, metalliferous sediments of the
global mid-ocean ridge hydrothermal vent system.
BibTeX:
@article{ISI:000309446000009,
  author = {Wankel, Scott D and Adams, Melissa M and Johnston, David T and Hansel, Colleen M and Joye, Samantha B and Girguis, Peter R},
  title = {Anaerobic methane oxidation in metalliferous hydrothermal sediments: influence on carbon flux and decoupling from sulfate reduction},
  journal = {ENVIRONMENTAL MICROBIOLOGY},
  year = {2012},
  volume = {14},
  number = {10, SI},
  pages = {2726--2740},
  doi = {10.1111/j.1462-2920.2012.02825.x}
}
Degen R, Riavitz L, Gollner S, Vanreusel A, Plum C and Bright M (2012), "Community study of tubeworm-associated epizooic meiobenthos from deep-sea cold seeps and hot vents", MARINE ECOLOGY PROGRESS SERIES. Vol. 468, pp. 135-148.
Abstract: The permanent metazoan meiofauna associated with vestimentiferan
tubeworm aggregations from hydrocarbon seeps of the upper Louisiana
slope in the Green Canyon (similar to 550 m) and the lower slope in
Atwater Valley (similar to 2200 m) of the Gulf of Mexico was
characterized. Meiofauna abundance, diversity, and community composition
at genus level were compared between these seep sites, and with those of
tubeworms from hydrothermal vents of the East Pacific Rise (Gollner et
al. 2007; Mar Ecol Prog Ser 337: 39-49). The abundance was not
significantly different between the 2 seep sites, and was also similar
to those found at vents. A total of 150 meiobenthic genera were
identified from the cold seep sites. While no significant difference in
univariate measurements of diversity was detected, a shift in community
composition between the shallow and the deep seep site was found. The
hot vent communities included a total of only 17 genera and the
diversity measurements were significantly lower at vents than at seeps.
Also, Bray-Curtis dissimilarity was 97% between the meiobenthic
communities from seeps and vents. The genera richness was negatively
correlated with maximum temperature and maximum sulfide concentration,
and positively correlated with minimum pH value. We conclude that the
harsh conditions tubeworms experience at vents compared to the moderate
conditions at cold seeps, as well as the longevity of cold seeps
surrounded by sedimented deep-sea plains but short-lived vents on
basaltic mid-ocean ridges, might explain the contrasting diversity
patterns.
BibTeX:
@article{ISI:000311041900011,
  author = {Degen, Renate and Riavitz, Laura and Gollner, Sabine and Vanreusel, Ann and Plum, Christoph and Bright, Monika},
  title = {Community study of tubeworm-associated epizooic meiobenthos from deep-sea cold seeps and hot vents},
  journal = {MARINE ECOLOGY PROGRESS SERIES},
  year = {2012},
  volume = {468},
  pages = {135--148},
  doi = {10.3354/meps09889}
}
Sammarco PW, Atchison AD, Boland GS, Sinclair J and Lirette A (2012), "Geographic expansion of hermatypic and ahermatypic corals in the Gulf of Mexico, and implications for dispersal and recruitment", JOURNAL OF EXPERIMENTAL MARINE BIOLOGY AND ECOLOGY., dec, 2012. Vol. 436, pp. 36-49.
Abstract: The textgreater3000 oil/gas platforms in the northern Gulf of Mexico (GOM) provide
shallow hard-substratum in a soft-bottom dominated ecosystem. Excepting
the Flower Garden Banks (FGB) and deeper mesophotic banks, no shallow
hard substrate has been available offshore since the Holocene. Platforms
have facilitated coral geographic expansion in this region. We
determined the distribution, abundance, and species diversity patterns
on 42 platforms in this region, at textless= 37 m depth, along four cross-shelf
transects: 1) S-SE from Corpus Christi, Texas; 2) S from Lake Sabine,
Texas; 3) S from Terrebonne Bay, Louisiana; and 4) S-SW from Mobile,
Alabama. Nine hermatypic, two ahermatypic, and one hydrozoan coral were
found: hermatypes-Madracis decactis. Diploria strigosa, Montastraea
cavernosa, Porites astreoides, Madracis formosa, Colpophyllia natans,
Stephanocoenia intercepta, Stephanocoenia michelinii, and Millepora
alcicornis (Hydrozoa); ahermatypes-Tubastraea cocci flea. Oculina
diffusa, and Phyllangia americana. Pattern-seeking analyses identified
four community types: one with no hermatypic corals (inner and
mid-shelf); one high diversity set of platforms, dominated by abundant
Madracis decactis, occurring with four other species per platform (outer
shelf); and a third dominated by Madracis decactis, in low abundance,
co-dominated by D. strigosa and Millepora alcicornis (outer shelf).
Species diversity was highest around the Flower Garden Banks. Hermatypic
density and D. strigosa (broadcaster) in particular, was maximum around
the FGB, extending northwards. Madracis decactis (brooder) densities
peaked at the shelf edge, off Terrebonne Bay, Louisiana. Montastraea
cavernosa densities were bimodal, peaking near the FGB and east of the
Mississippi River. The FGB appear to be the source of hermatypic corals
for most platform populations. Differences between the distribution
patterns of Madracis decactis and D. strigosa, Montastraea cavernosa,
and O. diffusa suggest that the brooder effects longer recruitment
distances by averaging larval dispersal over a broad range of
hydrographic conditions throughout the year, while the broadcaster
utilizes only one set of conditions over the same period. Averaging
respective dispersal strategies over decades may have produced the
observed disparate distribution patterns. Ahermatypic coral density
exceeded hermatypic density by 10,000 fold, peaking south of Terrebonne
Bay, Louisiana and Mobile, Alabama, due to T. coccinea. Ahermatypic
diversity was highest off Matagorda Island, Texas, decreasing from west
to east. Multi-variate pattern-seeking analysis (PATN) identified four
ahermatypic community types: one dominated by O. diffusa and T. coccinea
in low abundances (shelf-wide distribution); one characterized by the
absence of ahermatypic corals (generally near-shore); one heavily
dominated by T. coccinea, and also by O. diffusa in low abundances
(mid-shelf to shelf edge); and one dominated by T. coccinea,
co-dominated by both P. americana and O. diffusa in low abundances
(shelf-edge). T. coccinea and P. americana appear to be derived from the
southern GOM off Mexico or the Caribbean. Unlike shrinking coral
populations in other parts of the world, corals have expanded their
range substantially in the northern Gulf of Mexico, in areas previously
devoid or near devoid of corals, facilitated by thousands of oil/gas
platforms deployed for decades throughout the region.
It is also possible that coral populations on these platforms may act as
potential larval sources for the FGB in the event of a mass coral
mortality there. (C) 2012 Elsevier B.V. All rights reserved.
BibTeX:
@article{ISI:000311470800005,
  author = {Sammarco, Paul W and Atchison, Amy D and Boland, Gregory S and Sinclair, James and Lirette, Angela},
  title = {Geographic expansion of hermatypic and ahermatypic corals in the Gulf of Mexico, and implications for dispersal and recruitment},
  journal = {JOURNAL OF EXPERIMENTAL MARINE BIOLOGY AND ECOLOGY},
  year = {2012},
  volume = {436},
  pages = {36--49},
  doi = {10.1016/j.jembe.2012.08.009}
}
Perez-Rodriguez I, Grosche A, Massenburg L, Starovoytov V, Lutz RA and Vetriani C (2012), "Phorcysia thermohydrogeniphila gen. nov., sp nov., a thermophilic, chemolithoautotrophic, nitrate-ammonifying bacterium from a deep-sea hydrothermal vent", INTERNATIONAL JOURNAL OF SYSTEMATIC AND EVOLUTIONARY MICROBIOLOGY., oct, 2012. Vol. 62(10), pp. 2388-2394.
Abstract: A novel hyperthermophilic, anaerobic, chemolithoautotrophic bacterium,
designated strain HB-8(T), was isolated from the tube of Alvinella
pompejana tubeworms collected from the wall of an actively venting
sulfide structure on the East Pacific Rise at 13 degrees N. The cells
were Gram-negative rods, approximately 1.0-1.5 mu m long and 0.5 mu m
wide. Strain HB-8(T) grew between 65 and 80 degrees C (optimum 75
degrees C), 15 and 35 g NaCl l(-1) (optimum 30 gl(-1)) and pH 4.5 and
8.5 (optimum pH 6.0). Generation time under optimal conditions was 26
min. Growth occurred under chemolithoautotrophic conditions with H-2 as
the energy source and CO2 as the carbon source. Nitrate and sulfur were
used as electron acceptors, with concomitant formation of ammonium or
hydrogen sulfide, respectively. The presence of lactate, formate,
acetate or tryptone in the culture medium inhibited growth. The G+C
content of the genomic DNA was 47.8 mol%. Phylogenetic analysis of the
16S rRNA gene and of the alpha subunit of the ATP citrate lyase of
strain HB-8(T) indicated that this organism formed a novel lineage
within the class Aquificae, equally distant from the type strains of the
type species of the three genera that represent the family
Desulfurobacteriaceae: Thermovibrio ruber ED11/3LLK8(T), Balnearium
lithotrophicum 17S(T) and Desulfurobacterium thermolithotrophum BSA(T).
The polar lipids of strain HB-8(T) differed substantially from those of
other members of the Desulfurobacteriaceae, and this bacterium produced
novel quinones. On the basis of phylogenetic, physiological and
chemotaxonomic characteristics, it is proposed that the organism
represents a novel genus and species within the family
Desulfurobacteriaceae, Phorcysia thermohydrogeniphila gen. nov., sp.
nov. The type strain of Phorcysia thermohydrogeniphila is HB-8(T) (=DSM
24425(T) =JCM 17384(T)).
BibTeX:
@article{ISI:000311587800012,
  author = {Perez-Rodriguez, Ileana and Grosche, Ashley and Massenburg, Lynnicia and Starovoytov, Valentin and Lutz, Richard A and Vetriani, Costantino},
  title = {Phorcysia thermohydrogeniphila gen. nov., sp nov., a thermophilic, chemolithoautotrophic, nitrate-ammonifying bacterium from a deep-sea hydrothermal vent},
  journal = {INTERNATIONAL JOURNAL OF SYSTEMATIC AND EVOLUTIONARY MICROBIOLOGY},
  year = {2012},
  volume = {62},
  number = {10},
  pages = {2388--2394},
  doi = {10.1099/ijs.0.035642-0}
}
Slobodkin AI, Reysenbach AL, Slobodkina GB, Baslerov RV, Kostrikina NA, Wagner ID and Bonch-Osmolovskaya EA (2012), "Thermosulfurimonas dismutans gen. nov., sp nov., an extremely thermophilic sulfur-disproportionating bacterium from a deep-sea hydrothermal vent", INTERNATIONAL JOURNAL OF SYSTEMATIC AND EVOLUTIONARY MICROBIOLOGY., nov, 2012. Vol. 62(11), pp. 2565-2571.
Abstract: An extremely thermophilic, anaerobic, chemolithoautotrophic bacterium
(strain S95(T)) was isolated from a deep-sea hydrothermal vent chimney
located on the Eastern Lau Spreading Center, Pacific Ocean, at a depth
of 1910 m. Cells of strain S95(T) were oval to short Gram-negative rods,
0.5-0.6 mu m in diameter and 1.0-1.5 mu m in length, growing singly or
in pairs. Cells were motile with a single polar flagellum. The
temperature range for growth was 50-92 degrees C, with an optimum at 74
degrees C. The pH range for growth was 5.5-8.0, with an optimum at pH
7.0. Growth of strain S95(T) was observed at NaCl concentrations ranging
from 1.5 to 3.50/o (w/v). Strain S95(T) grew anaerobically with
elemental sulfur as an energy source and bicarbonate/CO2 as a carbon
source. Elemental sulfur was disproportionated to sulfide and sulfate.
Growth was enhanced in the presence of poorly crystalline iron(III)
oxide (ferrihydrite) as a sulfide-scavenging agent. Strain S95(T) was
also able to grow by disproportionation of thiosulfate and sulfite.
Sulfate was not used as an electron acceptor. Analysis of the 16S rRNA
gene sequence revealed that the isolate belongs to the phylum
Thermodesulfobacteria. On the basis of its physiological properties and
results of phylogenetic analyses, it is proposed that the isolate
represents the sole species of a new genus, Thermosulfurimonas dismutans
gen. nov., sp. nov.; S95(T) (=DSM 24515(T)=VKM B-2683(T)) is the type
strain of the type species. This is the first description of a
thermophilic microorganism that disproportionates elemental sulfur.
BibTeX:
@article{ISI:000312516200003,
  author = {Slobodkin, A I and Reysenbach, A -L. and Slobodkina, G B and Baslerov, R V and Kostrikina, N A and Wagner, I D and Bonch-Osmolovskaya, E A},
  title = {Thermosulfurimonas dismutans gen. nov., sp nov., an extremely thermophilic sulfur-disproportionating bacterium from a deep-sea hydrothermal vent},
  journal = {INTERNATIONAL JOURNAL OF SYSTEMATIC AND EVOLUTIONARY MICROBIOLOGY},
  year = {2012},
  volume = {62},
  number = {11},
  pages = {2565--2571},
  doi = {10.1099/ijs.0.034397-0}
}
Rosario-Passapera R, Keddis R, Wong R, Lutz RA, Staroyoytov V and Vetriani C (2012), "Parvibaculum hydrocarboniclasticum sp. nov., a mesophilic, alkane-oxidizing alphaproteobacterium isolated from a deep-sea hydrothermal vent on the East Pacific Rise", INTERNATIONAL JOURNAL OF SYSTEMATIC AND EVOLUTIONARY MICROBIOLOGY., dec, 2012. Vol. 62(12), pp. 2921-2926.
Abstract: An aerobic, alkane-oxidizing bacterium, designated strain EPR92(T), was
isolated from hydrothermal fluids that had been collected from a
deep-sea vent on the East Pacific Rise (at 9 degrees 50' N 104 degrees
17' W). The cells of the novel strain were Gram-staining-negative rods
that measured approximately 1.4 mu m in length and 0.4 mu m in width.
Strain EPR92T grew at 20-40 degrees C (optimum 35 degrees C), with
1.0-5.0% (w/v) NaCl (optimum 2.5%), and at pH 4.0-8.5 (optimum pH
7.5). The generation time under optimal conditions was 63 min. Strain
EPR92(T) grew aerobically in artificial seawater minimal medium with
n-alkanes as sole carbon and energy sources, and also in artificial
seawater medium supplemented with peptone and yeast extract. The
predominant fatty acids were C-18:1 omega 7c, C-19:0 cyclo omega 8c,
11-methyl C-18:1 omega 7c and a putative C-12:0 aldehyde. The major
polar lipids were phosphatidylglycerol, diphosphatidylglycerol,
phosphatidylethanolamine, phosphatidylcholine and four unidentified
aminolipids. The major respiratory quinone was Q-10 and the genomic DNA
G+C content was 60.7 mol%. Phylogenetic analyses of the 16S rRNA gene
showed that strain EPR92(T) belongs in the class Alphaproteobacteria and
the recognized species that were most closely related to the novel
strain were identified as Parvibaculum indicum P-31(T) (98.7% sequence
similarity) and Parvibaculum lavamentivorans DS-1(T) (95.8%). In
DNA-DNA hybridizations, the level of DNA-DNA relatedness observed
between strain EPR92(T) and P. indicum P-31(T) was 47.7%, indicating
that the two strains do not belong to the same species. Based on the
phylogenetic, physiological, chemotaxonomic and genetic evidence, strain
EPR92(T) represents a novel species within the genus Parvibaculum, for
which the name Parvibaculum hydrocarboniclasticum sp. nov. is proposed.
The type strain is EPR92(T) (=DSM 23209=JCM 16666(T)).
BibTeX:
@article{ISI:000315070000017,
  author = {Rosario-Passapera, Richard and Keddis, Ramaydalis and Wong, Ronald and Lutz, Richard A and Staroyoytov, Valentin and Vetriani, Costantino},
  title = {Parvibaculum hydrocarboniclasticum sp. nov., a mesophilic, alkane-oxidizing alphaproteobacterium isolated from a deep-sea hydrothermal vent on the East Pacific Rise},
  journal = {INTERNATIONAL JOURNAL OF SYSTEMATIC AND EVOLUTIONARY MICROBIOLOGY},
  year = {2012},
  volume = {62},
  number = {12},
  pages = {2921--2926},
  doi = {10.1099/ijs.0.039594-0}
}
Kaiser CL, Kinsey JC, Pinner W, Yoerger DR, German CR and Van Dover CL (2012), "Satellite based remote management and operation of a 6000m AUV", In Oceans, 2012. Vol. Hampton Ro
Abstract: During a July, 2012 expedition to the Hatteras Transverse Canyon, Blake Ridge, and Cape Fear Diapir, the AUV Sentry, aboard the NOAA Ship Okeanos, conducted experiments into remote operation of an AUV via satellite link. Remote launch, remote engineering, remote data processing and remote watch standing were all explored with varying degrees of success. Remote engineering and troubleshooting was found to be exceptionally promising and worthy of further effort. Remote data processing was a valuable addition for a telepresence enabled cruise where a substantial component of the science team was on shore. Remore watch standing and remote launch were both found to be viable though requiring improvement. Technology infrastructure is discussed along with successes, difficulties, and recommendations for future improvement.
BibTeX:
@inproceedings{Kaiser2012,
  author = {Kaiser, C L and Kinsey, J C and Pinner, W and Yoerger, D R and German, C R and Van Dover, C L},
  title = {Satellite based remote management and operation of a 6000m AUV},
  booktitle = {Oceans, 2012},
  year = {2012},
  volume = {Hampton Ro},
  doi = {10.1109/OCEANS.2012.6404900}
}
Kellermann MY, Schubotz F, Elvert M, Lipp JS, Birgel D, Prieto-Mollar X, Dubilier N and Hinrichs KU (2012), "Symbiont–host relationships in chemosynthetic mussels: A comprehensive lipid biomarker study", Organic Geochemistry. Vol. 43(0), pp. 112-124.
Abstract: Symbiosis with chemosynthetic microorganisms allows invertebrates from hydrothermal vents and cold seeps, such as mussels, snails and tubeworms, to gain nutrition independently of organic input from photosynthetic communities. Lipid biomarkers and their compound specific stable carbon isotopes (δ13C) have greatly aided the elucidation of chemosynthetic symbiosis. Due to recent methodological advances in liquid chromatography it is now possible to obtain a more holistic view of lipid biomarkers, including the analysis of intact polar membrane lipids (IPLs) and bacteriohopanepolyols (BHPs). This study provides an extensive examination of polar and apolar lipids in combination with stable carbon isotope analysis of three Bathymodiolus mussels (Bathymodiolus childressi, Bathymodiolus cf. thermophilus, Bathymodiolus brooksi) hosting different types of bacterial symbiont (methane-oxidizing, sulfur-oxidizing and a dual symbiosis with methane- and sulfur-oxidizing symbionts, respectively). We propose that IPLs with C16:1 acyl side chains, and phosphatidylglycerol (PG), diphosphatidylglycerol (DPG) and phosphatidylethanolamine (PE) head groups, which were only detected in the gill tissue, can be used as symbiont-characteristic biomarkers. These putative symbiont-specific IPLs provide the opportunity to detect and quantify the methanotrophic and thiotrophic symbionts within the gill tissue. Additional characteristic markers for methanotrophic symbionts were found in B. childressi and B. brooksi, including the BHP derivatives aminotriol and aminotetrol, 4-methyl sterols and diagnostic fatty acids (FAs), such as C16:1ω9, C16:1ω8, and C18:1ω8. In general, the δ13C values of FAs, alcohols and BHP-derived hopanols were in accordance with carbon assimilation pathways of the respective methanotrophic or thiotrophic symbionts in all three Bathymodiolus mussels. Differences in BHP distribution as well as δ13C values in the two mussels hosting a methanotrophic symbiont may indicate the presence of different methanotrophic symbionts and/or changes in the nutritional status. In all three mussel species the δ13C values of lipid biomarkers assigned to the symbionts were similar to those of the hosts, indicating the importance of the bacterial symbionts as the main carbon source for the mussel tissue.
BibTeX:
@article{Kellermann2012,
  author = {Kellermann, M Y and Schubotz, F and Elvert, M and Lipp, J S and Birgel, D and Prieto-Mollar, X and Dubilier, N and Hinrichs, K -U},
  title = {Symbiont–host relationships in chemosynthetic mussels: A comprehensive lipid biomarker study},
  journal = {Organic Geochemistry},
  year = {2012},
  volume = {43},
  number = {0},
  pages = {112--124},
  url = {http://dx.doi.org/10.1016/j.orggeochem.2011.10.005},
  doi = {10.1016/j.orggeochem.2011.10.005}
}
Kim S and Hammerstrom K (2012), "Hydrothermal vent community zonation along environmental gradients at the Lau back-arc spreading center", Deep-Sea Research. Part I: Oceanographic Research Papers. Vol. 62(0), pp. 10-19.
Abstract: The Lau back-arc spreading center exhibits gradients in hydrothermal vent habitat characteristics from north to south. Biological zonation within a few meters of vents has been described as temperature driven. We constructed georeferenced photomosaics of the seafloor out to tens of meters beyond vents to describe peripheral zonation and explore correlations between environmental conditions and the biological community. Cluster analysis separated northern sites from southern sites, corresponding to a break in substrate from basalt in the north to andesite in the south. Northern sites were dominated by anemones, and southern by sponges. A previous suggestion that dominants may be dependent on friability of the substrate was not supported; when visually distinguishable, individual species within taxa showed different patterns. Northern sites hosted proportionally more suspension feeding species. Sulfide that can support microbial food sources is at higher concentrations at these sites, though bathymetry that may enhance bottom currents is less rugged. Northern sites had higher diversity that may result from the overall northwards flow, which would generally permit easier dispersal downcurrent, though we observed no difference in dispersal strategies at different sites.
BibTeX:
@article{Kim2012,
  author = {Kim, S and Hammerstrom, K},
  title = {Hydrothermal vent community zonation along environmental gradients at the Lau back-arc spreading center},
  journal = {Deep-Sea Research. Part I: Oceanographic Research Papers},
  year = {2012},
  volume = {62},
  number = {0},
  pages = {10--19},
  url = {http://dx.doi.org/10.1016/j.dsr.2011.12.010},
  doi = {10.1016/j.dsr.2011.12.010}
}
Lang SQ, Fruh-Green GL, Bernasconi SM, Lilley MD, Proskurowski G, Mehay S and Butterfield DA (2012), "Microbial utilization of abiogenic carbon and hydrogen in a serpentinite-hosted system", Geochimica et Cosmochimica Acta. Vol. 92, pp. 82-99.
Abstract: Mantle rocks exposed on the seafloor constitute a highly reactive chemical and thermal system, in which interaction with seawater to produce serpentinite has major consequences for lithospheric cooling, global geochemical cycles, and microbial activity. Serpentinite-hosted hydrothermal activity is exemplified by the Lost City Hydrothermal Field (30°N, Mid-Atlantic Ridge) where fluid–rock reactions in the underlying ultramafic rocks result in high concentrations of abiotic hydrogen, methane, C2+ alkanes, and formate. Such systems have been proposed as possible analogs to the Early Earth environments that gave rise to the first biochemical pathways. Thus, characterizing the local microbial communities and their potential link with abiogenic compounds is of particular significance. Here we demonstrate that in active carbonate chimneys where microbial sulfate reduction is important, up to 50% of the microbial biomass is synthesized from mantle carbon. Conversely, mantle carbon contributes only ∼10% of the biomass in areas with minimal sulfate reduction. We attribute this difference to greater incorporation of formate or methane by the dominant microbial species, the Lost City Methanosarcinales, in locations where sulfate reducers are able to facilitate this assimilation. The ability of autotrophic communities at Lost City to capitalize on the steady stream of chemical products resulting from serpentinization reactions and to utilize abiogenic mantle carbon lend credence to the hypothesis that early biosynthetic pathways could have developed in similar environments.
BibTeX:
@article{Lang2012,
  author = {Lang, S Q and Fruh-Green, G L and Bernasconi, S M and Lilley, M D and Proskurowski, G and Mehay, S and Butterfield, D A},
  title = {Microbial utilization of abiogenic carbon and hydrogen in a serpentinite-hosted system},
  journal = {Geochimica et Cosmochimica Acta},
  year = {2012},
  volume = {92},
  pages = {82--99},
  url = {http://dx.doi.org/10.1016/j.gca.2012.06.006},
  doi = {10.1016/j.gca.2012.06.006}
}
Lemkau KL (2012), "Comprehensive study of a heavy fuel oil spill : modeling and analytical approaches to understanding environmental weathering" Cambridge, MA and Woods Hole, MA Vol. Ph.D. Massachusetts Institute of Technology and the Woods Hole Oceanographic Institution.
Abstract: Driven by increasingly heavy oil reserves and more efficient refining technologies, use of heavy fuel oils for power generation is rising. Unlike other refined products and crude oils, a large portion of these heavy oils is undetectable using the traditional gas chromatography-based techniques on which oil spill science has been based. In the current study, samples collected after the 2007 M/V Cosco Busan heavy fuel oil spill (San Francisco, CA) were analyzed using gas chromatography (GC)-based techniques, numerical modeling and Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) to examine natural weathering of the oil over a one and a half year period. Traditional GC techniques detected variable evidence of evaporation/ dissolution, biodegradation and photodegradation. Petroleum hydrocarbon compounds smaller than ˜n-C16 were rapidly lost due to evaporation and dissolution. Significant biodegradation was not detected until one month post spill while photodegradation was only observed at one field site. To further examine the processes of evaporation and dissolution, samples were analyzed with comprehensive two-dimensional GC (GC×GC) and a physiochemical model developed to approximate quantitative apportionment of compounds lost to the atmosphere and water. Model results suggest temperature is the primary control of evaporation. Finally, to examine the prominent non-GC amenable component of the oil, samples were analyzed with FT-ICR MS. Results showed expected clustering of samples, with those samples collected sooner after the spill having the most compositional similarity to the unweathered oil. Analysis of dominant heteroatom classes within the oil showed losses of high molecular weight species and the formation of stable core structures with time. These results highlight the susceptibility to weathering of these higher molecular weight components, previously believed to be recalcitrant in the environment. Research findings indicate that environmental weathering results in removal or alteration of larger alkylated compounds as well as loss of lower molecular weight species through evaporation/dissolution, biodegradation and photodegradation, with a resultant fraction of stable compounds likely to remain in the environment years after the spill. This research demonstrates the advantages of combining multiple analytical and modeling approaches for a fuller understanding of oil spill chemistry.
BibTeX:
@phdthesis{Lemkau2012,
  author = {Lemkau, K L},
  title = {Comprehensive study of a heavy fuel oil spill : modeling and analytical approaches to understanding environmental weathering},
  publisher = {Massachusetts Institute of Technology and the Woods Hole Oceanographic Institution},
  year = {2012},
  volume = {Ph.D.},
  doi = {10.1575/1912/5278}
}
Levin LA, Orphan VJ, Rouse GW, Rathburn AE, Ussler W, Cook GS, Goffredi SK, Perez EM, Waren A, Grupe BM, Chadwick G and Strickrott B (2012), "A hydrothermal seep on the Costa Rica margin: middle ground in a continuum of reducing ecosystems".
Abstract: Upon their initial discovery, hydrothermal vents and methane seeps were considered to be related but distinct ecosystems, with different distributions, geomorphology, temperatures, geochemical properties and mostly different species. However, subsequently discovered vents and seep systems have blurred this distinction. Here, we report on a composite, hydrothermal seep ecosystem at a subducting seamount on the convergent Costa Rica margin that represents an intermediate between vent and seep ecosystems. Diffuse flow of shimmering, warm fluids with high methane concentrations supports a mixture of microbes, animal species, assemblages and trophic pathways with vent and seep affinities. Their coexistence reinforces the continuity of reducing environments and exemplifies a setting conducive to interactive evolution of vent and seep biota.
BibTeX:
@misc{Levin2012,
  author = {Levin, L A and Orphan, V J and Rouse, G W and Rathburn, A E and Ussler, W and Cook, G S and Goffredi, S K and Perez, Elena M and Waren, A and Grupe, B M and Chadwick, G and Strickrott, B},
  title = {A hydrothermal seep on the Costa Rica margin: middle ground in a continuum of reducing ecosystems},
  booktitle = {Proceedings of the Royal Society B: Biological Sciences},
  year = {2012},
  volume = {279},
  number = {1738},
  pages = {2580--2588},
  url = {http://rspb.royalsocietypublishing.org/content/279/1738/2580.abstract},
  doi = {10.1098/rspb.2012.0205}
}
Lin HT, Cowen JP, Olson EJ, Amend JP and Lilley MD (2012), "Inorganic chemistry, gas compositions and dissolved organic carbon in fluids from sedimented young basaltic crust on the Juan de Fuca Ridge flanks", Geochimica et Cosmochimica Acta. Vol. 85, pp. 213-227.
Abstract: The permeable upper oceanic basement serves as a plausible habitat for a variety of microbial communities. There is growing evidence suggesting a substantial subseafloor biosphere. Here new time series data are presented on key inorganic species, methane, hydrogen and dissolved organic carbon (DOC) in ridge flank fluids obtained from subseafloor observatory CORKs (Circulation Obviation Retrofit Kits) at Integrated Ocean Drilling Program (IODP) boreholes 1301A and 1026B. These data show that the new sampling methods (Cowen et al., 2012) employed at 1301A result in lower contamination than earlier studies. Furthermore, sample collection methods permitted most chemical analyses to be performed from aliquots of single large volume samples, thereby allowing more direct comparison of the data. The low phosphate concentrations (0.06–0.2 μM) suggest that relative to carbon and nitrogen, phosphorus could be a limiting nutrient in the basement biosphere. Coexisting sulfate (17–18 mM), hydrogen sulfide (∼0.1 μM), hydrogen (0.3–0.7 μM) and methane (1.5–2 μM) indicates that the basement aquifer at 1301A either draws fluids from multiple flow paths with different redox histories or is a complex environment that is not thermodynamically controlled and may allow co-occurring metabolic pathways including sulfate reduction and methanogenesis. The low DOC concentrations (11–18 μM) confirm that ridge flank basement is a net DOC sink and ultimately a net carbon sink. Based on the net amounts of DOC, oxygen, nitrate and sulfate removed (∼30 μM, ∼80 μM, ∼40 μM and ∼10 mM, respectively) from entrained bottom seawater, organic carbon may be aerobically or anaerobically oxidized in biotic and/or abiotic processes.
BibTeX:
@article{Lin2012,
  author = {Lin, H -T and Cowen, J P and Olson, E J and Amend, J P and Lilley, M D},
  title = {Inorganic chemistry, gas compositions and dissolved organic carbon in fluids from sedimented young basaltic crust on the Juan de Fuca Ridge flanks},
  journal = {Geochimica et Cosmochimica Acta},
  year = {2012},
  volume = {85},
  pages = {213--227},
  url = {http://dx.doi.org/10.1016/j.gca.2012.02.017},
  doi = {10.1016/j.gca.2012.02.017}
}
Luther GW, Gartman A, Yuecel M, Madison AS, Moore TS, Nees HA, Nuzzio DB, Sen A, Lutz RA, Shank TM and Fisher CR (2012), "Chemistry, Temperature, and Faunal Distributions at Diffuse-Flow Hydrothermal Vents Comparison of Two Geologically Distinct Ridge Systems", Oceanography., mar, 2012. Vol. 25(1), pp. 234-245.
Abstract: Diffuse-flow, low-temperature areas near hydrothermal vents support life via chemosynthesis: hydrogen sulfide (and other reduced chemical compounds) emanating from the subsurface is oxidized with bottom-water oxygen through bacterial mediation to fix carbon dioxide and produce biomass. This article reviews the in situ diffuse-flow chemistry (mainly H2S and O2) and temperature data collected in 2006 and 2009 along the Eastern Lau Spreading Center (ELSC), and from 2004 to 2008 at 9°N along the East Pacific Rise (9 N EPR), predominantly around macrofauna that contain endosymbionts at these two hydrothermal vent regions. More than 48,000 and 20,000 distinct chemical and temperature data points were collected with a multi-analyte electrochemical analyzer in the diffuse-flow waters at 9 N EPR and the ELSC, respectively. Despite their different geological settings and different macrofauna (two different species of snails and mussels at the ELSC versus two different species of tubeworms and mussels at 9 N EPR), there are similarities in the temperature and chemistry data, as well as in the distributions of organisms. The pattern of water chemistry preferred by the provannid snails (Alviniconcha spp., Ifremeria nautilei) and Bathymodiolus brevior at the ELSC is similar to the water chemistry pattern found for the siboglinid tubeworms (Tevnia jerichonana, Riftia pachyptila) and the Bathymodiolus thermophilus mussels at 9 N EPR. The eruptions at 9 N EPR in 2005 and 2006 resulted in increased H2S concentrations, increased H2S/T ratios, and an initial change in the dominant tubeworm species from Riftia pachyptila to Tevnia jerichonana after the eruption created new vent habitats. In 2005, two sites at 9 N EPR showed major increases in the H2S/T ratio from 2004, which suggested a probable eruption in this basalt-dominated system. At the ELSC, there was a decrease in the H2S/T ratio from northern to southern sites, which reflects the change in geological setting from basalt to andesite and the shallower water depths at the southern sites.
BibTeX:
@article{Luther2012,
  author = {Luther, G W and Gartman, A and Yuecel, M and Madison, A S and Moore, T S and Nees, H A and Nuzzio, D B and Sen, A and Lutz, R A and Shank, T M and Fisher, C R},
  title = {Chemistry, Temperature, and Faunal Distributions at Diffuse-Flow Hydrothermal Vents Comparison of Two Geologically Distinct Ridge Systems},
  journal = {Oceanography},
  year = {2012},
  volume = {25},
  number = {1},
  pages = {234--245},
  doi = {10.5670/oceanog.2012.22}
}
McCulloch M, Trotter J, Montagna P, Falter J, Dunbar R, Freiwald A, Försterra G, Correa ML, Maier C, Rüggeberg A and Taviani M (2012), "Resilience of Cold-Water Scleractinian Corals to Ocean Acidification: Boron Isotopic Systematics of pH and Saturation State Up-Regulation", Geochimica et Cosmochimica Acta. Vol. 87, pp. 21-34.
Abstract: The boron isotope systematics has been determined for azooxanthellate scleractinian corals from a wide range of both deep-sea and shallow-water environments. The aragonitic coral species, Caryophyllia smithii, Desmophyllum dianthus, Enallopsammia rostrata, Lophelia pertusa, and Madrepora oculata, are all found to have relatively high δ11B compositions ranging from 23.2‰ to 28.7‰. These values lie substantially above the pH-dependent inorganic seawater borate equilibrium curve, indicative of strong up-regulation of pH of the internal calcifying fluid (pHcf), being elevated by ∼0.6–0.8 units (ΔpH) relative to ambient seawater. In contrast, the deep-sea calcitic coral Corallium sp. has a significantly lower δ11B composition of 15.5‰, with a corresponding lower ΔpH value of ∼0.3 units, reflecting the importance of mineralogical control on biological pH up-regulation. The solitary coral D. dianthus was sampled over a wide range of seawater pHT and shows an approximate linear correlation with ΔpHDesmo = 6.43 − 0.71pHT (r2 = 0.79). An improved correlation is however found with the closely related parameter of seawater aragonite saturation state, where ΔpHDesmo = 1.09 − 0.14Ωarag (r2 = 0.95), indicating the important control that carbonate saturation state has on calcification. The ability to up-regulate internal pHcf, and consequently Ωcf, of the calcifying fluid is therefore a process present in both azooxanthellate and zooxanthellate aragonitic corals, and is attributed to the action of Ca2+-ATPase in modulating the proton gradient between seawater and the site of calcification. These findings also show that the boron isotopic compositions (δ11Bcarb) of aragonitic corals are highly systematic and consistent with direct uptake of the borate species within the biologically controlled extracellular calcifying medium. We also show that the relatively strong up-regulation of pH and consequent elevation of the internal carbonate saturation state (Ωcf ∼8.5 to ∼13) at the site of calcification by cold-water corals, facilitates calcification at or in some cases below the aragonite saturation horizon, providing a greater ability to adapt to the already low and now decreasing carbonate ion concentrations. Although providing greater resilience to the effects of ocean acidification and enhancing rates of calcification with increasing temperature, the process of internal pHcf up-regulation has an associated energetic cost, and therefore growth-rate cost, of ∼10% per 0.1 pH unit decrease in seawater pHT. Furthermore, as the aragonite saturation horizon shoals with rapidly increasing pCO2 and Ωarag  
BibTeX:
@article{McCulloch2012,
  author = {McCulloch, M and Trotter, J and Montagna, P and Falter, J and Dunbar, R and Freiwald, A and Försterra, G and Correa, M L and Maier, C and Rüggeberg, A and Taviani, M},
  title = {Resilience of Cold-Water Scleractinian Corals to Ocean Acidification: Boron Isotopic Systematics of pH and Saturation State Up-Regulation},
  journal = {Geochimica et Cosmochimica Acta},
  year = {2012},
  volume = {87},
  pages = {21--34},
  url = {http://dx.doi.org/10.1016/j.gca.2012.03.027},
  doi = {10.1016/j.gca.2012.03.027}
}
McKay LJ, MacGregor BJ, Biddle JF, Albert DB, Mendlovitz HP, Hoer DR, Lipp JS, Lloyd KG and Teske AP (2012), "Spatial heterogeneity and underlying geochemistry of phylogenetically diverse orange and white Beggiatoa mats in Guaymas Basin hydrothermal sediments", Deep-Sea Research. Part I: Oceanographic Research Papers. Vol. 67, pp. 21-31.
Abstract: Sulfide-oxidizing bacteria of the genus Beggiatoa are found in conspicuous, colorful mats on the seafloor above active hydrothermal seeps at Guaymas Basin. Guaymas Beggiatoa filaments fall into discrete size classes representing at least five separate 16S rRNA phylotypes, and appear either white, yellow, or orange. During two R/V Atlantis cruises to Guaymas Basin, 78 temperature profiles were taken near and within 15 different orange and white Beggiatoa mats by the Alvin submersible to investigate spatial relationships between mat color and hydrothermal fluid seeps, as indicated by elevated temperatures. The surface temperatures from 78 profiles are similar to each other (on average 8–12 °C, warmer than bare sediments at 3–4 °C), indicating that Guaymas Basin Beggiatoa spp., although relying on the hydrothermal system for energy and carbon sources, live within a relatively cool temperature range. Temperatures from 40 cm below orange Beggiatoa versus white Beggiatoa are the same, at 84 °C averaged across all mat systems. However, within a single mat system, temperatures are higher beneath the predominantly orange center of the mat than beneath the white mat periphery. Push core transects across the orange-to-white color change of three Beggiatoa mats showed stronger upward compression of isotherms and metabolic zones beneath the orange mat center than beneath white mat periphery. Hydrothermal temperature gradients push the microbial processes generating carbon and energy sources for Beggiatoa mats towards the sediment surface. The resulting steep gradients of hydrothermal electron donors and carbon sources to the sediment surface, rather than the in situ temperature by itself, control the relative positioning of orange and white filaments within a Guaymas Basin Beggiatoa mat. Given the wide spectrum of temperature and hydrothermal flux regimes between different mats, the orange/white pattern represents a relative preference or even a competitive balance among different Beggiatoa types that establishes itself within each hydrothermal hot spot.
BibTeX:
@article{McKay2012,
  author = {McKay, L J and MacGregor, B J and Biddle, J F and Albert, D B and Mendlovitz, H P and Hoer, D R and Lipp, J S and Lloyd, K G and Teske, A P},
  title = {Spatial heterogeneity and underlying geochemistry of phylogenetically diverse orange and white Beggiatoa mats in Guaymas Basin hydrothermal sediments},
  journal = {Deep-Sea Research. Part I: Oceanographic Research Papers},
  year = {2012},
  volume = {67},
  pages = {21--31},
  url = {http://dx.doi.org/10.1016/j.dsr.2012.04.011},
  doi = {10.1016/j.dsr.2012.04.011}
}
Pester NJ, Reeves EP, Rough ME, Ding K, Seewald JS and Seyfried WE (2012), "Subseafloor phase equilibria in high-temperature hydrothermal fluids of the Lucky Strike Seamount (Mid-Atlantic Ridge, 37°17'N)", Geochimica et Cosmochimica Acta. Vol. 90, pp. 303-322.
Abstract: As part of an integrated study conducted at the Lucky Strike Seamount (Mid-Atlantic Ridge, 37°17′N) in 2008, gas-tight sampling devices were used to collect high-temperature (∼300 °C) hydrothermal fluids issuing from sulfide structures distributed throughout the vent field located in the summit depression. Compared with previous observations from 1993 to 1997, the most substantial changes in vent fluid compositions are dramatically increased CO2 concentrations (∼5×, up to 133 mmol/L) and the observation of vent fluids enriched in dissolved chloride relative to seawater. Combined with an increase in δ13CCO2δ13CCO2 values by ∼4‰ in 2008, the elevated CO2 indicates replenishment of the magmatic heat source and may be indicative of a recent magmatic event. The additional supporting fluid chemistry is, however, similar to that of the previous sampling intervals, necessitating a reassessment of the subseafloor controls on vent fluid chemistry at Lucky Strike in the context of recently obtained geophysical data that provides the depth/extent of a steady-state magma chamber. Two-phase behavior is indicated by the chloride variability in the vent fluids; and comparison with experimental data for the associated chloride-dependent partitioning of minor/trace elements suggests the possibility of a similar source fluid for all the vent structures, while limiting the likelihood of shallow phase separation and subseafloor mixing for the hydrothermal end-members. A recently calibrated Fe/Mn geothermometer indicates minimum subseafloor equilibration temperatures of 350–385 °C. However, constraints imposed by dissolved Si/Cl in conjunction with geophysical observations are consistent with peak reaction conditions at temperatures of 430–475 °C and pressures near the top of the axial magma chamber (∼410–480 bars), where magmatic CO2 becomes entrained in the circulating fluids. The distance between the magma chamber and the seafloor at Lucky Strike is substantially greater than at most faster spreading ridges; and we propose the resulting increased residence time in the up-flow zone leads to the re-equilibration of temperature sensitive transition metals at conditions less extreme than those associated with peak reaction. Agreement between experimental data, thermodynamic model calculations, and dissolved concentrations of Fe, Cu, Zn, H2, and H2S in the Lucky Strike fluids reinforce the hypothesis of pH-redox equilibria for transition metals at relatively oxidizing conditions and temperatures predicted by the empirical Fe/Mn geothermometer. In-situ pH measurements of the high-temperature fluids exiting the seafloor are also consistent with the model calculations.
BibTeX:
@article{Pester2012,
  author = {Pester, N J and Reeves, E P and Rough, M E and Ding, K and Seewald, J S and Seyfried, W E},
  title = {Subseafloor phase equilibria in high-temperature hydrothermal fluids of the Lucky Strike Seamount (Mid-Atlantic Ridge, 37°17'N)},
  journal = {Geochimica et Cosmochimica Acta},
  year = {2012},
  volume = {90},
  pages = {303--322},
  url = {http://dx.doi.org/10.1016/j.gca.2012.05.018},
  doi = {10.1016/j.gca.2012.05.018}
}
Robert K, Onthank KL, Juniper SK and Lee RW (2012), "Small-scale thermal responses of hydrothermal vent polynoid polychaetes: Preliminary in situ experiments and methodological development", Journal of Experimental Marine Biology and Ecology. Vol. 420-421, pp. 69-76.
Abstract: Hydrothermal vent systems represent a unique marine environment where high spatial variability allows the study of habitat selection with respect to small-scale temperature gradients. An autonomous time-lapse camera with a temperature logger array was deployed on four occasions to examine the thermal responses of two vent endemic polynoid polychaete taxa: Branchinotogluma sp. and Lepidonotopodium piscesae. Over a total deployment time of 52 h, we collected over 3,400 frames, in which 1,700 individuals were observed and monitored. Automated image processing and particle tracking routines were used to quickly process the imagery acquired in situ. Kriging interpolation was employed to create temperature maps (2.5–67 °C) of the field of view within which individual polynoids were tracked over time. Using the individual trajectories, we examined whether organisms selected for a narrower range of temperature than available in the environment and whether past information regarding the temperature encountered influenced subsequent movement decisions. A two state hidden Markov model was applied to predict behaviour based on movement patterns and examine whether areas characterized by different movement patterns differed in temperature. We found polynoids to be active over a wide range of temperatures and areas where different movement patterns were observed did not differ in temperature. Within their tolerated range of temperature, polynoids appear to thermoconform to the highly spatially variable thermal environment. Based on these preliminary deployments, we make suggestions for future studies over broader thermal regimes and longer time scales.
BibTeX:
@article{Robert2012,
  author = {Robert, K and Onthank, K L and Juniper, S K and Lee, R W},
  title = {Small-scale thermal responses of hydrothermal vent polynoid polychaetes: Preliminary in situ experiments and methodological development},
  journal = {Journal of Experimental Marine Biology and Ecology},
  year = {2012},
  volume = {420-421},
  pages = {69--76},
  url = {http://dx.doi.org/10.1016/j.jembe.2012.03.019},
  doi = {10.1016/j.jembe.2012.03.019}
}
Rubin KH, Soule SA, Chadwick WW, Fornari DJ, Clague DA, Embley RW, Baker ET, Perfit MR, Caress DW and Dziak RP (2012), "Volcanic Eruptions in the Deep Sea", Oceanography. ROCKVILLE; P.O. BOX 1931, ROCKVILLE, MD USA, mar, 2012. Vol. 25(1), pp. 142-157. OCEANOGRAPHY SOC.
Abstract: Volcanic eruptions are important events in Earth's cycle of magma generation and crustal construction. Over durations of hours to years, eruptions produce new deposits of lava and/or fragmentary ejecta, transfer heat and magmatic volatiles from Earth's interior to the overlying air or seawater, and significantly modify the landscape and perturb local ecosystems. Today and through most of geological history, the greatest number and volume of volcanic eruptions on Earth have occurred in the deep ocean along mid-ocean ridges, near subduction zones, on oceanic plateaus, and on thousands of mid-plate seamounts. However, deep-sea eruptions (textgreater 500 m depth) are much more difficult to detect and observe than subaerial eruptions, so comparatively little is known about them. Great strides have been made in eruption detection, response speed, and observational detail since the first recognition of a deep submarine eruption at a mid-ocean ridge 25 years ago. Studies of ongoing or recent deep submarine eruptions reveal information about their sizes, durations, frequencies, styles, and environmental impacts. Ultimately, magma formation and accumulation in the upper mantle and crust, plus local tectonic stress fields, dictate when, where, and how often submarine eruptions occur, whereas eruption depth, magma composition, conditions of volatile segregation, and tectonic setting determine submarine eruption style.
BibTeX:
@article{Rubin2012,
  author = {Rubin, K H and Soule, S A and Chadwick, W W and Fornari, D J and Clague, D A and Embley, R W and Baker, E T and Perfit, M R and Caress, D W and Dziak, R P},
  title = {Volcanic Eruptions in the Deep Sea},
  journal = {Oceanography},
  publisher = {OCEANOGRAPHY SOC},
  year = {2012},
  volume = {25},
  number = {1},
  pages = {142--157},
  doi = {10.5670/oceanog.2012.12}
}
Schimak MP, Toenshoff ER and Bright M (2012), "Simultaneous 16S and 18S rRNA fluorescence in situ hybridization (FISH) on LR White sections demonstrated in Vestimentifera (Siboglinidae) tubeworms", Acta Histochemica. Vol. 114(2), pp. 122-130.
Abstract: Traditional morphological identification of invertebrate marine species is limited in early life history stages for many taxa. In this study, we demonstrate, by example of Vestimentiferan tubeworms (Siboglinidae, Polychaeta), that the simultaneous fluorescence in situ hybridization (FISH) of both eukaryotic host and bacterial symbiont cells is possible on a single semi-thin (1 μm) section. This allows the identification of host specimens to species level as well as offering visualization of bacteria distributed within the host tissue. Previously published 18S rRNA host-specific oligonucleotide probes for Riftia pachyptila, Tevnia jerichonana and a newly designed Oasisia alvinae probe, as well as a 16S rRNA probe targeting symbionts found in all host species, were applied. A number of standard fixation and hybridization parameters were tested and optimized for the best possible signal intensity and cellular resolution. Ethanol conserved samples embedded in LR White low viscosity resin yielded the best results with regard to both signal intensity and resolution. We show that extended storage times of specimens does not affect the quality of signals attained by FISH and use our protocol to identify morphologically unidentifiable tubeworm individuals from a small data set, conforming to previous findings in succession studies of the Siboglinidae family.
BibTeX:
@article{Schimak2012,
  author = {Schimak, M P and Toenshoff, E R and Bright, M},
  title = {Simultaneous 16S and 18S rRNA fluorescence in situ hybridization (FISH) on LR White sections demonstrated in Vestimentifera (Siboglinidae) tubeworms},
  journal = {Acta Histochemica},
  year = {2012},
  volume = {114},
  number = {2},
  pages = {122--130},
  url = {http://dx.doi.org/10.1016/j.acthis.2011.03.008},
  doi = {10.1016/j.acthis.2011.03.008}
}
Soule SA, Nakata DS, Fornari DJ, Fundis AT, Perfit MR and Kurz MD (2012), "CO2 variability in mid-ocean ridge basalts from syn-emplacement degassing: Constraints on eruption dynamics", Earth and Planetary Science Letters. Vol. 327–328(0), pp. 39-49.
Abstract: Basaltic glasses produced during mid-ocean ridge (MOR) eruptions display a wide range of dissolved CO2 concentrations with respect to equilibrium saturation at their eruption depth. This variability is thought to reflect the dynamics of magma ascent and emplacement, with rapid ascent and depressurization leading to supersaturated conditions and slower ascent resulting in equilibrium saturation. In this study we examine a suite of samples from the 2005–06 eruption of the East Pacific Rise (EPR), collected at ˜ 200 m intervals along two well-defined flow pathways within a single seafloor eruption to examine syn-emplacement degassing, using measurements of vesicularity, crystallinity, volatile contents, and helium. This new data set is unique because flow pathways of individual MOR lava flows have rarely been mapped and have never been systematically sampled. Here we show that a large range in dissolved CO2 concentrations exists within this single eruption that nearly spans that observed in tens of flows measured along this portion of the EPR crest. This lava flow experienced equilibrium degassing of dissolved CO2 from supersaturated conditions at the vent (and persisting over the first 750 m of flow) toward equilibrium with seafloor pressures along a ˜ 2.5 km-long flow path. This was accompanied by an increase in vesicularity and characteristic bubble radius along the flow, indicating the importance of bubble growth by diffusion for degassing. Nearly constant total helium concentrations (melt + vesicles) indicate that no bubbles were lost during emplacement. With a model of diffusion-controlled bubble growth constrained by observations from the samples along the largest flow lobe of the eruption, we calculate minimum ascent rates of 0.15 m/s, and – for this portion of the eruption – an eruption duration of ˜ 30 h and flow rates from 0.02 to 0.12 m/s. This study represents the first quantitative assessment of eruption dynamics using volatiles in a mid-ocean ridge lava flow.
BibTeX:
@article{Soule2012,
  author = {Soule, S A and Nakata, D S and Fornari, D J and Fundis, A T and Perfit, M R and Kurz, M D},
  title = {CO2 variability in mid-ocean ridge basalts from syn-emplacement degassing: Constraints on eruption dynamics},
  journal = {Earth and Planetary Science Letters},
  year = {2012},
  volume = {327–328},
  number = {0},
  pages = {39--49},
  url = {http://dx.doi.org/10.1016/j.epsl.2012.01.034},
  doi = {10.1016/j.epsl.2012.01.034}
}
Stanway MJ (2012), "Contributions to automated realtime underwater navigation" Cambridge, MA and Woods Hole, MA Vol. Ph.D. Massachusetts Institute of Technology and the Woods Hole Oceanographic Institution.
Abstract: This dissertation presents three separate–but related–contributions to the art of underwater navigation. These methods may be used in postprocessing with a human in the loop, but the overarching goal is to enhance vehicle autonomy, so the emphasis is on automated approaches that can be used in realtime. The three research threads are: i) in situ navigation sensor alignment, ii) dead reckoning through the water column, and iii) model-driven delayed measurement fusion. Contributions to each of these areas have been demonstrated in simulation, with laboratory data, or in the field–some have been demonstrated in all three arenas. The solution to the in situ navigation sensor alignment problem is an asymptotically stable adaptive identifier formulated using rotors in Geometric Algebra. This identifier is applied to precisely estimate the unknown alignment between a gyrocompass and Doppler velocity log, with the goal of improving realtime dead reckoning navigation. Laboratory and field results show the identifier performs comparably to previously reported methods using rotation matrices, providing an alignment estimate that reduces the position residuals between dead reckoning and an external acoustic positioning system. The Geometric Algebra formulation also encourages a straightforward interpretation of the identifier as a proportional feedback regulator on the observable output error. Future applications of the identifier may include alignment between inertial, visual, and acoustic sensors. The ability to link the Global Positioning System at the surface to precision dead reckoning near the seafloor might enable new kinds of missions for autonomous underwater vehicles. This research introduces a method for dead reckoning through the water column using water current profile data collected by an onboard acoustic Doppler current profiler. Overlapping relative current profiles provide information to simultaneously estimate the vehicle velocity and local ocean current–the vehicle velocity is then integrated to estimate position. The method is applied to field data using online bin average, weighted least squares, and recursive least squares implementations. This demonstrates an autonomous navigation link between the surface and the seafloor without any dependence on a ship or external acoustic tracking systems. Finally, in many state estimation applications, delayed measurements present an interesting challenge. Underwater navigation is a particularly compelling case because of the relatively long delays inherent in all available position measurements. This research develops a flexible, model-driven approach to delayed measurement fusion in realtime Kalman filters. Using a priori estimates of delayed measurements as augmented states minimizes the computational cost of the delay treatment. Managing the augmented states with time-varying conditional process and measurement models ensures the approach works within the proven Kalman filter framework–without altering the filter structure or requiring any ad-hoc adjustments. The end result is a mathematically principled treatment of the delay that leads to more consistent estimates with lower error and uncertainty. Field results from dead reckoning aided by acoustic positioning systems demonstrate the applicability of this approach to real-world problems in underwater navigation.
BibTeX:
@phdthesis{Stanway2012,
  author = {Stanway, M J},
  title = {Contributions to automated realtime underwater navigation},
  publisher = {Massachusetts Institute of Technology and the Woods Hole Oceanographic Institution},
  year = {2012},
  volume = {Ph.D.},
  doi = {10.1575/1912/5095}
}
Thaler AD, Van Dover CL and Vilgalys R (2012), "Ascomycete phylotypes recovered from a Gulf of Mexico methane seep are identical to an uncultured deep-sea fungal clade from the Pacific", Fungal Ecology., apr, 2012. Vol. 5(2), pp. 270-273.
Abstract: Deep-sea endemic fungi are one component of an under-sampled invisible biosphere whose contribution to benthic ecosystems is not yet understood. In the last decade, molecular techniques have facilitated the discovery of several new deep-sea fungal groups, especially in habitats such as hydrothermal vents and methane seeps. We assessed fungal diversity at a methane seep in the Gulf of Mexico by sequencing partial ITS and LSU gene regions from environmental DNA recovered from microoxic and anoxic sediment. While most phylotypes were closely allied with common fungal species, the dominant phylotype did not match any known terrestrial species and aligned with an uncultured deep-sea fungus found in oxygen-depleted sediment at multiple sites in the Pacific Ocean. Despite its apparently broad distribution and frequent occurrence in oxygen-depleted sediment, the ecological role of this phylotype is not yet known. (C) 2011 Elsevier Ltd and The British Mycological Society. All rights reserved.
BibTeX:
@article{Thaler2012,
  author = {Thaler, A D and Van Dover, C L and Vilgalys, R},
  title = {Ascomycete phylotypes recovered from a Gulf of Mexico methane seep are identical to an uncultured deep-sea fungal clade from the Pacific},
  journal = {Fungal Ecology},
  year = {2012},
  volume = {5},
  number = {2},
  pages = {270--273},
  doi = {10.1016/j.funeco.2011.07.002}
}
Thiel V, Hugler M, Blümel M, Baumann HI, Gärtner A, Schmaljohann R, Strauss H, Garbe-Schonberg D, Petersen S, Cowart DA, Fisher CR and Imhoff JF (2012), "Widespread occurrence of two carbon fixation pathways in tubeworm endosymbionts: lessons from hydrothermal vent associated tubeworms from the Mediterranean Sea", Frontiers in Microbiology. Vol. 2, pp. 423.
Abstract: Vestimentiferan tubeworms (siboglinid polychetes) of the genus Lamellibrachia are common members of cold seep faunal communities and have also been found at sedimented hydrothermal vent sites in the Pacific. As they lack a digestive system, they are nourished by chemoautotrophic bacterial endosymbionts growing in a specialized tissue called the trophosome. Here we present the results of investigations of tubeworms and endosymbionts from a shallow hydrothermal vent field in the Western Mediterranean Sea. The tubeworms, which are the first reported vent-associated tubeworms outside the Pacific, are identified as Lamellibrachia anaximandri using mitochondrial ribosomal and cytochrome oxidase I (COI) gene sequences. They harbor a single gammaproteobacterial endosymbiont. Carbon isotopic data, as well as the analysis of genes involved in carbon and sulfur metabolism indicate a sulfide-oxidizing chemoautotrophic endosymbiont. The detection of a hydrogenase gene fragment suggests the potential for hydrogen oxidation as alternative energy source. Surprisingly, the endosymbiont harbors genes for two different carbon fixation pathways, the Calvin-Benson-Bassham (CBB) cycle as well as the reductive tricarboxylic acid (rTCA) cycle, as has been reported for the endosymbiont of the vent tubeworm Riftia pachyptila. In addition to RubisCO genes we detected ATP citrate lyase (ACL – the key enzyme of the rTCA cycle) type II gene sequences using newly designed primer sets. Comparative investigations with additional tubeworm species (Lamellibrachia luymesi, Lamellibrachia sp. 1, Lamellibrachia sp. 2, Escarpia laminata, Seepiophila jonesi) from multiple cold seep sites in the Gulf of Mexico revealed the presence of acl genes in these species as well. Thus, our study suggests that the presence of two different carbon fixation pathways, the CBB cycle and the rTCA cycle, is not restricted to the Riftia endosymbiont, but rather might be common in vestimentiferan tubeworm endosymbionts, regardless of the habitat.
BibTeX:
@article{Thiel2012,
  author = {Thiel, Vera and Hugler, M and Blümel, M and Baumann, H I and Gärtner, A and Schmaljohann, R and Strauss, H and Garbe-Schonberg, D and Petersen, S and Cowart, D A and Fisher, C R and Imhoff, J F},
  title = {Widespread occurrence of two carbon fixation pathways in tubeworm endosymbionts: lessons from hydrothermal vent associated tubeworms from the Mediterranean Sea},
  journal = {Frontiers in Microbiology},
  year = {2012},
  volume = {2},
  pages = {423},
  doi = {10.3389/fmicb.2012.00423}
}
Thornhill DJ, Struck TH, Ebbe B, Lee RW, Mendoza GF, Levin LA and Halanych KM (2012), "Adaptive radiation in extremophilic Dorvilleidae (Annelida): diversification of a single colonizer or multiple independent lineages?", Ecology and Evolution. Vol. 2(8), pp. 1958-1970.
Abstract: Metazoan inhabitants of extreme environments typically evolved from forms found in less extreme habitats. Understanding the prevalence with which animals move into and ultimately thrive in extreme environments is critical to elucidating how complex life adapts to extreme conditions. Methane seep sediments along the Oregon and California margins have low oxygen and very high hydrogen sulfide levels, rendering them inhospitable to many life forms. Nonetheless, several closely related lineages of dorvilleid annelids, including members of Ophryotrocha, Parougia, and Exallopus, thrive at these sites in association with bacterial mats and vesicomyid clam beds. These organisms are ideal for examining adaptive radiations in extreme environments. Did dorvilleid annelids invade these extreme environments once and then diversify? Alternatively, did multiple independent lineages adapt to seep conditions? To address these questions, we examined the evolutionary history of methane-seep dorvilleids using 16S and Cyt b genes in an ecological context. Our results indicate that dorvilleids invaded these extreme habitats at least four times, implying preadaptation to life at seeps. Additionally, we recovered considerably more dorvilleid diversity than is currently recognized. A total of 3 major clades (designated “ Ophryotrocha,” “Mixed Genera” and “ Parougia”) and 12 terminal lineages or species were encountered. Two of these lineages represented a known species, Parougia oregonensis, whereas the remaining 10 lineages were newly discovered species. Certain lineages exhibited affinity to geography, habitat, sediment depth, and/or diet, suggesting that dorvilleids at methane seeps radiated via specialization and resource partitioning.
BibTeX:
@article{Thornhill2012,
  author = {Thornhill, D J and Struck, T H and Ebbe, B and Lee, R W and Mendoza, G F and Levin, L A and Halanych, K M},
  title = {Adaptive radiation in extremophilic Dorvilleidae (Annelida): diversification of a single colonizer or multiple independent lineages?},
  journal = {Ecology and Evolution},
  year = {2012},
  volume = {2},
  number = {8},
  pages = {1958--1970},
  url = {http://dx.doi.org/10.1002/ece3.314},
  doi = {10.1002/ece3.314}
}
Thurber AR, Levin LA, Orphan VJ and Marlow JJ (2012), "Archaea in metazoan diets: implications for food webs and biogeochemical cycling", ISME Journal. Vol. 6(8), pp. 1602-1612. International Society for Microbial Ecology.
Abstract: Although the importance of trophic linkages, including ‘top-down forcing', on energy flow and ecosystem productivity is recognized, the influence of metazoan grazing on Archaea and the biogeochemical processes that they mediate is unknown. Here, we test if: (1) Archaea provide a food source sufficient to allow metazoan fauna to complete their life cycle; (2) neutral lipid biomarkers (including crocetane) can be used to identify Archaea consumers; and (3) archaeal aggregates are a dietary source for methane seep metazoans. In the laboratory, we demonstrated that a dorvilleid polychaete, Ophryotrocha labronica, can complete its life cycle on two strains of Euryarchaeota with the same growth rate as when fed bacterial and eukaryotic food. Archaea were therefore confirmed as a digestible and nutritious food source sufficient to sustain metazoan populations. Both strains of Euryarchaeota used as food sources had unique lipids that were not incorporated into O. labronica tissues. At methane seeps, sulfate-reducing bacteria that form aggregations and live syntrophically with anaerobic-methane oxidizing Archaea contain isotopically and structurally unique fatty acids (FAs). These biomarkers were incorporated into tissues of an endolithofaunal dorvilleid polychaete species from Costa Rica (mean bulk δ13C=−92±4‰; polar lipids −116‰) documenting consumption of archaeal-bacterial aggregates. FA composition of additional soft-sediment methane seep species from Oregon and California provided evidence that consumption of archaeal-bacterial aggregates is widespread at methane seeps. This work is the first to show that Archaea are consumed by heterotrophic metazoans, a trophic process we coin as ‘archivory'.
BibTeX:
@article{Thurber2012,
  author = {Thurber, A R and Levin, L A and Orphan, V J and Marlow, J J},
  title = {Archaea in metazoan diets: implications for food webs and biogeochemical cycling},
  journal = {ISME Journal},
  publisher = {International Society for Microbial Ecology},
  year = {2012},
  volume = {6},
  number = {8},
  pages = {1602--1612},
  url = {http://www.nature.com/ismej/journal/v6/n8/suppinfo/ismej201216s1.html},
  doi = {10.1038/ismej.2012.16}
}
Tivey MK, Becker E, Beinart R, Fisher CR, Girguis PR, Langmuir CH, Michael PJ and Reysenbach AL (2012), "Links from Mantle to Microbe at the Lau Integrated Study Site:Insights from a Back-Arc Spreading Center", Oceanography., mar, 2012. Vol. 25(1), pp. 62-77.
Abstract: The Lau Integrated Study Site (ISS) has provided unique opportunities for study of ridge processes because of its back-arc setting in the southwestern Pacific. Its location allows study of a biogeographical province distinct from those of eastern Pacific and mid-Atlantic ridges, and crustal compositions along the ridge lie outside the range of mid-ocean ridge crustal compositions. The Lau ISS is located above a subduction zone, at an oblique angle. The underlying mantle receives water and other elements derived from the downgoing lithospheric slab, with an increase in slab influence from north to south. Water lowers the mantle melting temperature and leads to greater melt production where the water flux is greater, and to distinctive regional-scale gradients along the ridge. There are deeper faulted axial valleys with basaltic volcanism in the north and inflated axial highs with andesites in the south. Differences in igneous rock composition and release of magmatic volatiles affect compositions of vent fluids and deposits. Differences in vent fluid compositions and small-scale diffuse-flow regimes correlate with regional-scale patterns in microbial and megafaunal distributions. The interdisciplinary research effort at the Lau ISS has successfully identified linkages between subsurface processes and deep-sea biological communities, from mantle to microbe to megafauna.
BibTeX:
@article{Tivey2012,
  author = {Tivey, M K and Becker, E and Beinart, R and Fisher, C R and Girguis, P R and Langmuir, C H and Michael, P J and Reysenbach, A -L},
  title = {Links from Mantle to Microbe at the Lau Integrated Study Site:Insights from a Back-Arc Spreading Center},
  journal = {Oceanography},
  year = {2012},
  volume = {25},
  number = {1},
  pages = {62--77},
  doi = {10.5670/oceanog.2012.04}
}
Ventura GT, Simoneit BRT, Nelson RK and Reddy CM (2012), "The composition, origin and fate of complex mixtures in the maltene fractions of hydrothermal petroleum assessed by comprehensive two-dimensional gas chromatography", Organic Geochemistry. Vol. 45(0), pp. 48-65.
Abstract: Sedimentary organic matter in hydrothermal systems can be altered by high temperature fluids to generate petroleum. The saturated and aromatic fractions of these hydrothermal oils are compositionally similar to conventional oil with the exception that they often contain higher concentrations of polycyclic aromatic hydrocarbons (PAH) as well as substantial mixtures of coeluting organic compounds that produce dramatically rising signal on the baseline of gas chromatograms termed unresolved complex mixtures (UCMs). Little is known about the compounds that compose UCMs and why or how they form. This is in part due to an inability to discriminate between in situ and migrated components that characterize the petroleum generated in hydrothermal systems. However, UCMs are also a product of the limitations imbedded in analytical separation techniques. With the advent of comprehensive two-dimensional gas chromatography (GC × GC), a revision of what should constitute molecular complexity needs to be considered. We address these problems by comparing the molecular compositions of the maltene fractions of three previously published hydrothermal petroleum samples using time of flight-mass spectrometry (GC × GC–ToF-MS) and 12 hydrothermal petroleum samples in cores from three locales using comprehensive two-dimensional gas chromatography with flame ionization detection (GC × GC–FID). The sediment cores were collected from Middle Valley, located off the axis of the Juan de Fuca Ridge, and the Escanaba Trough, along the Gorda Ridge, both in the NE Pacific Ocean, as well as from the Guaymas Basin in the Gulf of California. We define a UCM in GC × GC data to be a condition in which ⩾25% of the detected peaks within a chromatographic area coelute in either the first or second dimension. In turn, complex (CM) and simple mixtures (SM) are defined as having 5–24% and and migrated components that characterize the petroleum generated in hydrothermal systems. However, UCMs are also a product of the limitations imbedded in analytical separation techniques. With the advent of comprehensive two-dimensional gas chromatography (GC × GC), a revision of what should constitute molecular complexity needs to be considered. We address these problems by comparing the molecular compositions of the maltene fractions of three previously published hydrothermal petroleum samples using time of flight-mass spectrometry (GC × GC–ToF-MS) and 12 hydrothermal petroleum samples in cores from three locales using comprehensive two-dimensional gas chromatography with flame ionization detection (GC × GC–FID). The sediment cores were collected from Middle Valley, located off the axis of the Juan de Fuca Ridge, and the Escanaba Trough, along the Gorda Ridge, both in the NE Pacific Ocean, as well as from the Guaymas Basin in the Gulf of California. We define a UCM in GC × GC data to be a condition in which ⩾25% of the detected peaks within a chromatographic area coelute in either the first or second dimension. In turn, complex (CM) and simple mixtures (SM) are defined as having 5–24% and
BibTeX:
@article{Ventura2012,
  author = {Ventura, G T and Simoneit, B R T and Nelson, R K and Reddy, C M},
  title = {The composition, origin and fate of complex mixtures in the maltene fractions of hydrothermal petroleum assessed by comprehensive two-dimensional gas chromatography},
  journal = {Organic Geochemistry},
  year = {2012},
  volume = {45},
  number = {0},
  pages = {48--65},
  url = {http://dx.doi.org/10.1016/j.orggeochem.2012.01.002},
  doi = {10.1016/j.orggeochem.2012.01.002}
}
Voight JR, Lee RW, Reft AJ and Bates AE (2012), "Scientific Gear as a Vector for Non-Native Species at Deep-Sea Hydrothermal Vents", Conservation Biology., oct, 2012. Vol. 26(5), pp. 938-942.
Abstract: The fauna of deep-sea hydrothermal vents are among the most isolated and inaccessible biological communities on Earth. Most vent sites can only be visited by subsea vehicles, which can and do move freely among these communities. Researchers assume individuals of the regionally homogeneous vent fauna are killed by the change in hydrostatic pressure the animals experience when the subsea vehicles, which collected them, rise to the surface. After an Alvin dive, we found 38 apparently healthy individuals of a vent limpet in a sample from a hydrothermally inactive area. Prompted by our identification of these specimens as Lepetodrilus gordensis, a species restricted to vents 635 km to the south of our dive site, we tested whether they were from a novel population or were contaminants from the dive made 36 h earlier. The 16S gene sequences, morphology, sex ratio, bacterial colonies, and stable isotopes uniformly indicated the specimens came from the previous dive. We cleaned the sampler, but assumed pressure changes would kill any organisms we did not remove and that the faunas of the 2 areas were nearly identical and disease-free. Our failure to completely clean the gear on the subsea vehicle meant we could have introduced the species and any diseases it carried to a novel location. Our findings suggest that the nearly inaccessible biological communities at deep-sea vents may be vulnerable to anthropogenic alteration, despite their extreme physical conditions.
BibTeX:
@article{Voight2012,
  author = {Voight, J R and Lee, R W and Reft, A J and Bates, A E},
  title = {Scientific Gear as a Vector for Non-Native Species at Deep-Sea Hydrothermal Vents},
  journal = {Conservation Biology},
  year = {2012},
  volume = {26},
  number = {5},
  pages = {938--942},
  doi = {10.1111/j.1523-1739.2012.01864.x}
}
Wang XM, Shang JH, Luo Z, Tang L, Zhang X and Li J (2012), "Reviews of power systems and environmental energy conversion for unmanned underwater vehicles", Renewable and Sustainable Energy Reviews. Vol. 16(4), pp. 1958-1970.
Abstract: The power supply for unmanned underwater vehicles has been an important research point since the vehicles were invented. The power systems and environmental energy conversions for the vehicles are reviewed in the paper. Several topics are represented: problems and general solutions for unmanned underwater vehicles power supplies; the mechanisms and structures of tether power system; characteristics of several batteries; the characterization of potential environmental energy, and energy conversion for unmanned underwater vehicles. Docking stations for underwater vehicles continuation are also represented in the paper. Some typical vehicles powered by the power systems and their performances are listed and analyzed.
BibTeX:
@article{Wang2012,
  author = {Wang, X -M and Shang, J -H and Luo, Zirong and Tang, Li and Zhang, X and Li, J},
  title = {Reviews of power systems and environmental energy conversion for unmanned underwater vehicles},
  journal = {Renewable and Sustainable Energy Reviews},
  year = {2012},
  volume = {16},
  number = {4},
  pages = {1958--1970},
  url = {http://dx.doi.org/10.1016/j.rser.2011.12.016},
  doi = {10.1016/j.rser.2011.12.016}
}
White HK, Hsing P-Y, Cho W, Shank TM, Cordes EE, Quattrini AM, Nelson RK, Camilli R, Demopoulos AWJ, German CR, Brooks JM, Roberts HH, Shedd W, Reddy CM and Fisher CR (2012), "Impact of the Deepwater Horizon oil spill on a deep-water coral community in the Gulf of Mexico", Proceedings of the National Academy of Sciences of the United States of America., dec, 2012. Vol. 109(50), pp. 20303-20308.
Abstract: To assess the potential impact of the Deepwater Horizon oil spill on offshore ecosystems, 11 sites hosting deep-water coral communities were examined 3 to 4 mo after the well was capped. Healthy coral communities were observed at all sites textgreater20 km from the Macondo well, including seven sites previously visited in September 2009, where the corals and communities appeared unchanged. However, at one site 11 km southwest of the Macondo well, coral colonies presented widespread signs of stress, including varying degrees of tissue loss, sclerite enlargement, excess mucous production, bleached commensal ophiuroids, and covering by brown flocculent material (floc). On the basis of these criteria the level of impact to individual colonies was ranked from 0 (least impact) to 4 (greatest impact). Of the 43 corals imaged at that site, 46% exhibited evidence of impact on more than half of the colony, whereas nearly a quarter of all of the corals showed impact to textgreater90% of the colony. Additionally, 53% of these corals' ophiuroid associates displayed abnormal color and/or attachment posture. Analysis of hopanoid petroleum biomarkers isolated from the floc provides strong evidence that this material contained oil from the Macondo well. The presence of recently damaged and deceased corals beneath the path of a previously documented plume emanating from the Macondo well provides compelling evidence that the oil impacted deep-water ecosystems. Our findings underscore the unprecedented nature of the spill in terms of its magnitude, release at depth, and impact to deep-water ecosystems.
BibTeX:
@article{White2012,
  author = {White, H K and Hsing, P-Y and Cho, W and Shank, T M and Cordes, E E and Quattrini, A M and Nelson, R K and Camilli, R and Demopoulos, A W J and German, C R and Brooks, J M and Roberts, H H and Shedd, W and Reddy, C M and Fisher, C R},
  title = {Impact of the Deepwater Horizon oil spill on a deep-water coral community in the Gulf of Mexico},
  journal = {Proceedings of the National Academy of Sciences of the United States of America},
  year = {2012},
  volume = {109},
  number = {50},
  pages = {20303--20308},
  doi = {10.1073/pnas.1118029109}
}
White HK, Hsing P-Y, Cho W, Shank TM, Cordes EE, Quattrini AM, Nelson RK, Camilli R, Demopoulos AWJ, German CR, Brooks JM, Roberts HH, Shedd W, Reddy CM and Fisher CR (2012), "Reply to Boehm and Carragher: Multiple lines of evidence link deep-water coral damage to Deepwater Horizon oil spill", Proceedings of the National Academy of Sciences of the United States of America., oct, 2012. Vol. 109(40), pp. E2648-E2648.
Abstract: Our original study (1) used visual inspection as well as biological and geochemical analyses of corals and the surrounding sediment to provide complementary and compelling evidence linking the Deepwater Horizon (DWH) oil spill to the presence of damaged deep-water corals and brittle stars 11 km from the site of the leaking oil.
BibTeX:
@article{White2012a,
  author = {White, H K and Hsing, P-Y and Cho, W and Shank, T M and Cordes, E E and Quattrini, A M and Nelson, R K and Camilli, R and Demopoulos, A W J and German, C R and Brooks, J M and Roberts, H H and Shedd, W and Reddy, C M and Fisher, C R},
  title = {Reply to Boehm and Carragher: Multiple lines of evidence link deep-water coral damage to Deepwater Horizon oil spill},
  journal = {Proceedings of the National Academy of Sciences of the United States of America},
  year = {2012},
  volume = {109},
  number = {40},
  pages = {E2648--E2648},
  doi = {10.1073/pnas.1210413109}
}
(2012), "Alvin Submersible's New Sphere Passes Pressure Tests", Sea Technology. Vol. 53(8), pp. 65.
BibTeX:
@article{,,
  title = {Alvin Submersible's New Sphere Passes Pressure Tests},
  journal = {Sea Technology},
  year = {2012},
  volume = {53},
  number = {8},
  pages = {65}
}
Adams DK, McGillicuddy DJ, Zamudio L, Thurnherr AM, Liang X, Rouxel OJ, German CR and Mullineaux LS (2011), "Surface-generated mesoscale eddies transport deep-sea products from hydrothermal vents", Science. Vol. 332(6029), pp. 580-583.
Abstract: Atmospheric forcing, which is known to have a strong influence on surface ocean dynamics and production, is typically not considered in studies of the deep sea. Our observations and models demonstrate an unexpected influence of surface-generated mesoscale eddies in the transport of hydrothermal vent efflux and of vent larvae away from the northern East Pacific Rise. Transport by these deep-reaching eddies provides a mechanism for spreading the hydrothermal chemical and heat flux into the deep-ocean interior and for dispersing propagules hundreds of kilometers between isolated and ephemeral communities. Because the eddies interacting with the East Pacific Rise are formed seasonally and are sensitive to phenomena such as El Niño, they have the potential to introduce seasonal to interannual atmospheric variations into the deep sea.
BibTeX:
@article{Adams2011,
  author = {Adams, D K and McGillicuddy, D J and Zamudio, L and Thurnherr, A M and Liang, X and Rouxel, O J and German, C R and Mullineaux, L S},
  title = {Surface-generated mesoscale eddies transport deep-sea products from hydrothermal vents},
  journal = {Science},
  year = {2011},
  volume = {332},
  number = {6029},
  pages = {580--583},
  url = {http://dx.doi.org/10.1126/science.1201066},
  doi = {10.1126/science.1201066}
}
Bailey JV, Salman V, Rouse GW, Schulz-Vogt H, Levin LA and Orphan VJ (2011), "Dimorphism in methane seep-dwelling ecotypes of the largest known bacteria", ISME Journal. Vol. 5(12), pp. 1926-1935. International Society for Microbial Ecology.
Abstract: We present evidence for a dimorphic life cycle in the vacuolate sulfide-oxidizing bacteria that appears to involve the attachment of a spherical Thiomargarita-like cell to the exteriors of invertebrate integuments and other benthic substrates at methane seeps. The attached cell elongates to produce a stalk-like form before budding off spherical daughter cells resembling free-living Thiomargarita that are abundant in surrounding sulfidic seep sediments. The relationship between the attached parent cell and free-living daughter cell is reminiscent of the dimorphic life modes of the prosthecate Alphaproteobacteria, but on a grand scale, with individual elongate cells reaching nearly a millimeter in length. Abundant growth of attached Thiomargarita-like bacteria on the integuments of gastropods and other seep fauna provides not only a novel ecological niche for these giant bacteria, but also for animals that may benefit from epibiont colonization.
BibTeX:
@article{Bailey2011,
  author = {Bailey, J V and Salman, V and Rouse, G W and Schulz-Vogt, H and Levin, L A and Orphan, V J},
  title = {Dimorphism in methane seep-dwelling ecotypes of the largest known bacteria},
  journal = {ISME Journal},
  publisher = {International Society for Microbial Ecology},
  year = {2011},
  volume = {5},
  number = {12},
  pages = {1926--1935},
  url = {http://www.nature.com/ismej/journal/v5/n12/suppinfo/ismej201166s1.html 10.1038/ismej.2011.66},
  doi = {10.1038/ismej.2011.66}
}
Barr SM, Mortensen JK, Thompson MD, Hermes OD and White CE (2011), "Early to Middle Devonian granitic and volcanic rocks from the central Gulf of Maine", Lithos. Vol. 126(3-4), pp. 455-465.
Abstract: Cashes Ledge igneous suite in the central Gulf of Maine is represented by 10 granitic and two felsic tuff samples collected from bedrock outcrops using the submersible Alvin in 1971–1972 and archived at the Woods Hole Oceanographic Institute. Laser ablation ICP-MS analyses of zircon grains yielded crystallization ages of 414.9 ± 1.1 Ma and 399.7 ± 1.5 Ma for two alkali feldspar granite samples, 407.0 ± 1.9 Ma for a syenogranite sample, and 384.4 ± 2.3 Ma and 383.9 ± 1.6 Ma for two felsic tuff samples. The samples contain iron-rich mafic minerals, including aegirine-augite, grunerite/ferroedenite, and annite. Most of the samples are alkaline to slightly peralkaline, with high concentrations of SiO2, Y, Zr, Nb, and REE, strong negative Eu anomalies, and positive epsilon Nd values (1.8 to 3.7). The suite resembles part of a belt of similar Silurian–Devonian rocks with ages between 426 and 370 Ma now recognized in the central part of Avalonia in southeastern New England. They formed in a long-lived, likely extensional regime linked to subduction and subsequent complex transcurrent motions among Ganderia, Avalonia, and Meguma, culminating in the closure of the Rheic Ocean.
BibTeX:
@article{Barr2011,
  author = {Barr, S M and Mortensen, J K and Thompson, M D and Hermes, O D and White, C E},
  title = {Early to Middle Devonian granitic and volcanic rocks from the central Gulf of Maine},
  journal = {Lithos},
  year = {2011},
  volume = {126},
  number = {3-4},
  pages = {455--465},
  url = {http://dx.doi.org/10.1016/j.lithos.2011.06.009},
  doi = {10.1016/j.lithos.2011.06.009}
}
Bayer S (2011), "Reproductive traits of pioneer gastropod species colonizing deepsea hydrothermal vents after an eruption" Cambridge, MA and Woods Hole, MA Vol. M.S., pp. 49. Massachusetts Institute of Technology and Woods Hole Oceanographic Institution.
Abstract: The colonization dynamics and life histories of pioneer species are vital components in understanding the early succession of nascent hydrothermal vents. The reproductive ecology of pioneer species at deep-sea hydrothermal vents may provide insight into their dispersal, population connectivity, and ability to colonize after disturbance. An opportunity to study the reproductive traits of two pioneer gastropod species, Ctenopelta porifera and Lepetodrilus tevnianus, presented itself in 2006 after an eruption on the East Pacific Rise (EPR) eliminated vent communities near 9°50ʹ′N. Standard histological techniques were used to determine whether reproductive characteristics, such as timing of gamete release, fecundity, or time to maturation, differed from other vent gastropods in ways that might explain arrival of these two species as early colonizers. Both species exhibited two-component oocyte size frequency distributions that indicated they were quasi-continuous reproducers with high fecundity. In C. porifera, the oocyte size distributions differed slightly between two collection dates, suggesting that environmental cues may introduce some variability in gamete release. In samples collected within one year of the estimated eruption date, individuals in populations of both C. porifera and L. tevnianus were reproductively mature. The smallest reproducing C. porifera were 4.2 mm (males) and 5.4 mm (females) in shell length, whereas reproductive L. tevnianus were smaller (2.3 and 2.4 mm in males and females respectively). Most C porifera in the population were large (textgreater 6.0 mm) compared to their settlement size and reproductively mature. In contrast, most L tevnianus were small (
BibTeX:
@phdthesis{Bayer2011,
  author = {Bayer, S},
  title = {Reproductive traits of pioneer gastropod species colonizing deepsea hydrothermal vents after an eruption},
  publisher = {Massachusetts Institute of Technology and Woods Hole Oceanographic Institution},
  year = {2011},
  volume = {M.S.},
  pages = {49},
  url = {http://hdl.handle.net/1912/4733},
  doi = {10.1575/1912/4733}
}
Becker EL, Macko SA, Lee RW and Fisher CR (2011), "Stable isotopes provide new insights into vestimentiferan physiological ecology at Gulf of Mexico cold seeps", Naturwissenschaften., feb, 2011. Vol. 98(2), pp. 169-174.
Abstract: On the otherwise low-biomass seafloor of the Gulf of Mexico (GoM) continental slope, natural oil and gas seeps are oases of local primary production that support lush animal communities. Hundreds of seep communities have been documented on the continental slope, and nutrition derived from seeps could be an important link in the overall GoM food web. Here, we present a uniquely large and cohesive data set of δ13C, δ15N, and δ34S compositions of the vestimentiferan tubeworms Escarpia laminata and Lamellibrachia sp. 1, which dominate biomass at GoM seeps and provide habitat for hundreds of other species. Our sampling design encompassed an entire region of the GoM lower slope, allowing us for the first time to assess spatial variability in isotope compositions and to robustly address long-standing hypotheses about how vestimentiferans acquire and cycle nutrients over their long lifespan (200+ years). Tissue δ13C values provided strong evidence that larger adult vestimentiferans use their buried roots to take up dissolved inorganic carbon from sediment pore water, while very small individuals use their plume to take up carbon dioxide from the seawater. δ34S values were extremely variable among individuals of the same species within one location (S values were extremely variable among individuals of the same species within one location (2 area), indicating high variability in the inorganic sulfur pools on a very small spatial scale. This finding supports the hypothesis that vestimentiferans use their roots to cycle sulfate and sulfide between their symbionts and free-living consortia of sulfate-reducing archaea in the sediment. Finally, consistent differences in δ15N between two cooccurring vestimentiferan species provided the first strong evidence for partitioning of inorganic resources, which has significant implications for the ecology and evolution of this taxonomic group.
BibTeX:
@article{Becker2011,
  author = {Becker, E L and Macko, S A and Lee, R W and Fisher, C R},
  title = {Stable isotopes provide new insights into vestimentiferan physiological ecology at Gulf of Mexico cold seeps},
  journal = {Naturwissenschaften},
  year = {2011},
  volume = {98},
  number = {2},
  pages = {169--174},
  doi = {10.1007/s00114-010-0754-z}
}
Bennett SA, Statham PJ, Green DRH, Le Bris N, McDermott JM, Prado F, Rouxel OJ, Von Damm KL and German CR (2011), "Dissolved and particulate organic carbon in hydrothermal plumes from the East Pacific Rise, 9 degrees 50′N", Deep-Sea Research. Part I: Oceanographic Research Papers. Vol. 58(9), pp. 922-931.
Abstract: Chemoautotrophic production in seafloor hydrothermal systems has the potential to provide an important source of organic carbon that is exported to the surrounding deep-ocean. While hydrothermal plumes may export carbon, entrained from chimney walls and biologically rich diffuse flow areas, away from sites of venting they also have the potential to provide an environment for in-situ carbon fixation. In this study, we have followed the fate of dissolved and particulate organic carbon (DOC and POC) as it is dispersed through and settles beneath a hydrothermal plume system at 9°50′N on the East Pacific Rise. Concentrations of both DOC and POC are elevated in buoyant plume samples that were collected directly above sites of active venting using both DSV Alvin and a CTD-rosette. Similar levels of POC enrichment are also observed in the dispersing non-buoyant plume, ∼500 m downstream from the vent-site. Further, sediment-trap samples collected beneath the same dispersing plume system, show evidence for a close coupling between organic carbon and Fe oxyhydroxide fluxes. We propose, therefore, a process that concentrates POC into hydrothermal plumes as they disperse through the deep-ocean. This is most probably the result of some combination of preferential adsorption of organic carbon onto Fe-oxyhydroxides and/or microbial activity that preferentially concentrates organic carbon in association with Fe-oxyhydroxides (e.g. through the microbial oxidation of Fe(II) and Fe sulfides). This potential for biological production and consumption within hydrothermal plumes highlights the importance of a multidisciplinary approach to understanding the role of the carbon cycle in deep-sea hydrothermal systems as well as the role that hydrothermal systems may play in regulating global deep-ocean carbon budgets.
BibTeX:
@article{Bennett2011,
  author = {Bennett, S A and Statham, P J and Green, D R H and Le Bris, N and McDermott, J M and Prado, F and Rouxel, O J and Von Damm, K L and German, C R},
  title = {Dissolved and particulate organic carbon in hydrothermal plumes from the East Pacific Rise, 9 degrees 50′N},
  journal = {Deep-Sea Research. Part I: Oceanographic Research Papers},
  year = {2011},
  volume = {58},
  number = {9},
  pages = {922--931},
  url = {http://dx.doi.org/10.1016/j.dsr.2011.06.010},
  doi = {10.1016/j.dsr.2011.06.010}
}
Bennett SA, Hansman RL, Sessions AL, Nakamura K and Edwards KJ (2011), "Tracing iron-fueled microbial carbon production within the hydrothermal plume at the Loihi Seamount", Geochimica et Cosmochimica Acta. Vol. 75(19), pp. 5526-5539.
Abstract: The Loihi hydrothermal plume provides an opportunity to investigate iron (Fe) oxidation and microbial processes in a system that is truly Fe dominated and distinct from mid-ocean ridge spreading centers. The lack of hydrogen sulfide within the Loihi hydrothermal fluids and the presence of an oxygen minimum zone at this submarine volcano's summit, results in a prolonged presence of reduced Fe within the dispersing non-buoyant plume. In this study, we have investigated the potential for microbial carbon fixation within the Loihi plume. We sampled for both particulate and dissolved organic carbon in hydrothermal fluids, microbial mats growing around vents, and the dispersing plume, and carried out stable carbon isotope analysis on the particulate fraction. The δ13C values of the microbial mats ranged from −23‰ to −28‰, and are distinct from those of deep-ocean particulate organic carbon (POC). The mats and hydrothermal fluids were also elevated in dissolved organic carbon (DOC) compared to background seawater. Within the hydrothermal plume, DOC and POC concentrations were elevated and the isotopic composition of POC within the plume suggests mixing between background seawater POC and a 13C-depleted hydrothermal component. The combination of both DOC and POC increasing in the dispersing plume that cannot solely be the result of entrainment and DOC adsorption, provides strong evidence for in-situ microbial productivity by chemolithoautotrophs, including a likelihood for iron-oxidizing microorganisms.
BibTeX:
@article{Bennett2011a,
  author = {Bennett, S A and Hansman, R L and Sessions, A L and Nakamura, K and Edwards, K J},
  title = {Tracing iron-fueled microbial carbon production within the hydrothermal plume at the Loihi Seamount},
  journal = {Geochimica et Cosmochimica Acta},
  year = {2011},
  volume = {75},
  number = {19},
  pages = {5526--5539},
  url = {http://dx.doi.org/10.1016/j.gca.2011.06.039},
  doi = {10.1016/j.gca.2011.06.039}
}
Birgel D, Feng D, Roberts HH and Peckmann J (2011), "Changing redox conditions at cold seeps as revealed by authigenic carbonates from Alaminos Canyon, northern Gulf of Mexico", Chemical Geology. Vol. 285(1-4), pp. 82-96.
Abstract: Anaerobic oxidation of methane in anoxic sediments at cold seeps often leads to formation of authigenic carbonates close to the seafloor along continental margins. Recent work, however, indicated that the redox conditions in sediments may vary to some degree during seepage activity. In order to shed new light on the extent of this variability, authigenic carbonates from Alaminos Canyon lease block 645 of the northern Gulf of Mexico have been characterized by means of inorganic and organic geochemistry. The carbonates were collected from seep deposits representing various seafloor morphologies, including extensive pavements, mounds, fractured carbonate slabs surrounded by dense bivalve shells, and vestimentiferan tubeworm colonies. The deposits almost entirely consist of aragonite. The δ18O values of aragonite vary from + 2.6 to + 5.8‰ V-PDB, suggesting precipitation in slight disequilibrium with the surrounding pore fluids. The δ13C values of aragonite between − 33.9 and − 20.4‰ V-PDB agree with variable amounts of carbonate derived from oxidation of thermogenic methane and crude oil. Methane was primarily oxidized in an anaerobic process as revealed by the presence of 13C-depleted molecular fossils of methane-oxidizing archaea (δ13C values as negative as − 118‰) and sulfate-reducing bacteria (δ13C values as negative as − 97‰), the syntrophic partners in the anaerobic oxidation of methane. The observed inventories of molecular fossils in the authigenic carbonates mirror those of known consortia of anaerobic methane oxidizing archaea (ANME) and sulfate-reducing bacteria, namely the ANME-2/Desulfosarcina/Desulfococcus (DSS) and ANME-3/Desulfobulbus (DBB) consortia. In contrast, the same carbonates exhibit shale-normalized rare earth elements patterns that all display real negative Ce anomalies (Ce/Ce*  In contrast, the same carbonates exhibit shale-normalized rare earth elements patterns that all display real negative Ce anomalies (Ce/Ce* 13C values of the biomarkers of aerobic methanotrophs are as negative as − 58‰ and are consequently less 13C-depleted than the molecular fossils of the prokaryotes performing anaerobic oxidation of methane, a pattern in accord with culture experiments. Overall, our results suggest that redox conditions at cold seeps are variable. This variability probably reflects changes in seepage flux. The combination of an inorganic and an organic geochemical approach used here is promising to better assess the variability and diversity of past fluid and gas expulsion at seeps.
BibTeX:
@article{Birgel2011,
  author = {Birgel, D and Feng, D and Roberts, H H and Peckmann, J},
  title = {Changing redox conditions at cold seeps as revealed by authigenic carbonates from Alaminos Canyon, northern Gulf of Mexico},
  journal = {Chemical Geology},
  year = {2011},
  volume = {285},
  number = {1-4},
  pages = {82--96},
  url = {http://dx.doi.org/10.1016/j.chemgeo.2011.03.004},
  doi = {10.1016/j.chemgeo.2011.03.004}
}
Blackman DK, Ildefonse B, John BE, Ohara Y, Miller DJ, Abe N, Abratis M, Andal ES, Andreani M, Awaji S, Beard JS, Brunelli D, Charney AB, Christie DM, Collins J, Delacour AG, Delius H, Drouin M, Einaudi F, Escartin J, Frost BR, Frueh-Green G, Fryer PB, Gee JS, Godard M, Grimes CB, Halfpenny A, Hansen HE, Harris AC, Tamura A, Hayman NW, Hellebrand E, Hirose T, Hirth JG, Ishimaru S, Johnson KTM, Karner GD, Linek M, MacLeod CJ, Maeda J, Mason OU, McCaig AM, Michibayashi K, Morris A, Nakagawa T, Nozaka T, Rosner M, Searle RC, Suhr G, Tominaga M, von der Handt A, Yamasaki T and Zhao X (2011), "Drilling constraints on lithospheric accretion and evolution at Atlantis Massif, Mid-Atlantic Ridge 30 degrees N", Journal of Geophysical Research: Solid Earth. WASHINGTON; 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA, jul, 2011. Vol. 116, pp. B07103-B07103. AMER GEOPHYSICAL UNION.
Abstract: Expeditions 304 and 305 of the Integrated Ocean Drilling Program cored and logged a 1.4 km section of the domal core of Atlantis Massif. Postdrilling research results summarized here constrain the structure and lithology of the Central Dome of this oceanic core complex. The dominantly gabbroic sequence recovered contrasts with predrilling predictions; application of the ground truth in subsequent geophysical processing has produced self-consistent models for the Central Dome. The presence of many thin interfingered petrologic units indicates that the intrusions forming the domal core were emplaced over a minimum of 100-220 kyr, and not as a single magma pulse. Isotopic and mineralogical alteration is intense in the upper 100 m but decreases in intensity with depth. Below 800 m, alteration is restricted to narrow zones surrounding faults, veins, igneous contacts, and to an interval of locally intense serpentinization in olivine-rich troctolite. Hydration of the lithosphere occurred over the complete range of temperature conditions from granulite to zeolite facies, but was predominantly in the amphibolite and greenschist range. Deformation of the sequence was remarkably localized, despite paleomagnetic indications that the dome has undergone at least 45 degrees rotation, presumably during unroofing via detachment faulting. Both the deformation pattern and the lithology contrast with what is known from seafloor studies on the adjacent Southern Ridge of the massif. There, the detachment capping the domal core deformed a 100 m thick zone and serpentinized peridotite comprises similar to 70% of recovered samples. We develop a working model of the evolution of Atlantis Massif over the past 2 Myr, outlining several stages that could explain the observed similarities and differences between the Central Dome and the Southern Ridge.
BibTeX:
@article{Blackman2011,
  author = {Blackman, D K and Ildefonse, B and John, B E and Ohara, Y and Miller, D J and Abe, N and Abratis, M and Andal, E S and Andreani, M and Awaji, S and Beard, J S and Brunelli, D and Charney, A B and Christie, D M and Collins, J and Delacour, A G and Delius, H and Drouin, M and Einaudi, F and Escartin, J and Frost, B R and Frueh-Green, G and Fryer, P B and Gee, J S and Godard, M and Grimes, C B and Halfpenny, A and Hansen, H -E and Harris, A C and Tamura, A and Hayman, N W and Hellebrand, E and Hirose, T and Hirth, J G and Ishimaru, S and Johnson, K T M and Karner, G D and Linek, M and MacLeod, C J and Maeda, J and Mason, O U and McCaig, A M and Michibayashi, K and Morris, A and Nakagawa, T and Nozaka, T and Rosner, M and Searle, R C and Suhr, G and Tominaga, M and von der Handt, A and Yamasaki, T and Zhao, X},
  title = {Drilling constraints on lithospheric accretion and evolution at Atlantis Massif, Mid-Atlantic Ridge 30 degrees N},
  journal = {Journal of Geophysical Research: Solid Earth},
  publisher = {AMER GEOPHYSICAL UNION},
  year = {2011},
  volume = {116},
  pages = {B07103--B07103},
  doi = {10.1029/2010JB007931}
}
Clague DA, Paduan JB, Caress DW, Thomas H, Chadwick WW and Merle SG (2011), "Volcanic morphology of West Mata Volcano, NE Lau Basin, based on high-resolution bathymetry and depth changes", Geochemistry, Geophysics, Geosystems. WASHINGTON; 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA, nov, 2011. Vol. 12, pp. QOAF03-QOAF03. AMER GEOPHYSICAL UNION.
Abstract: High-resolution (1.5 m) mapping from the autonomous underwater vehicle (AUV) D. Allan B. of West Mata Volcano in the northern Lau Basin is used to identify the processes that construct and modify the volcano. The surface consists largely of volcaniclastic debris that forms smooth slopes to the NW and SE, with smaller lava flows forming gently sloping plateaus concentrated along the ENE and WSW rift zones, and more elongate flows radiating from the summit. Two active volcanic vents, Prometheus and Hades, are located ∼50 and ∼150 m WSW of the 1159 m summit, respectively, and are slightly NW of the ridgeline so the most abundant clastic deposits are emplaced on the NW flank. This eruptive activity and the location of vents appears to have been persistent for more than a decade, based on comparison of ship-based bathymetric surveys in 1996 and 2008–2010, which show positive depth changes up to 96 m on the summit and north flank of the volcano. The widespread distribution of clastic deposits downslope from the rift zones, as well as from the current vents, suggests that pyroclastic activity occurs at least as deep as 2200 m. The similar morphology of additional nearby volcanoes suggests that they too have abundant pyroclastic deposits.
BibTeX:
@article{Clague2011,
  author = {Clague, D A and Paduan, J B and Caress, D W and Thomas, Hans and Chadwick, W W and Merle, S G},
  title = {Volcanic morphology of West Mata Volcano, NE Lau Basin, based on high-resolution bathymetry and depth changes},
  journal = {Geochemistry, Geophysics, Geosystems},
  publisher = {AMER GEOPHYSICAL UNION},
  year = {2011},
  volume = {12},
  pages = {QOAF03--QOAF03},
  doi = {10.1029/2011GC003791}
}
Davis E, Heesemann M and Wang K (2011), "Evidence for episodic aseismic slip across the subduction seismogenic zone off Costa Rica: CORK borehole pressure observations at the subduction prism toe", Earth and Planetary Science Letters. Vol. 306(3-4), pp. 299-305.
Abstract: Slow slip events, or “silent” earthquakes, may relieve a significant amount of stress at many subduction plate boundaries, both downdip of the limit of seismogenesis, and within the seismogenic zone itself in cases where seismic energy release accounts for only a fraction of the plate tectonic displacement rate (Schwartz and Rokosky, 2007). Slow slip has been identified in several instances downdip of the landward limit of the seismogenic zone and is often accompanied by seismic tremor or low-frequency earthquake activity along and above the plate interface (referred to as “episodic tremor and slip”, or ETS). Little is known, however, about the spatial distribution and history of slip between great earthquakes along the seismogenic thrust interface itself which lies mostly offshore. In this article we present formation pressure transients observed in two deep-sea boreholes near the toe of the subduction prism off Nicoya Peninsula, Costa Rica, which followed ETS events observed on shore by 1–2 weeks. The signatures of the transients are consistent with local slip on the shallow part of the thrust interface, with the underthrusting plate experiencing relaxation and the outer prism experiencing contraction. The delay between the tremor activity and the pressure transients observed c. 100 km seaward at the prism toe suggests either slow propagation across the seismogenic zone or delayed deformation at the outer part of the prism triggered by the slip beneath Nicoya. Such slip may serve generally to relieve stress at subduction zones, but also to increase stress in parts of the plate boundary where interseismic slip does not occur.
BibTeX:
@article{Davis2011,
  author = {Davis, E and Heesemann, M and Wang, K},
  title = {Evidence for episodic aseismic slip across the subduction seismogenic zone off Costa Rica: CORK borehole pressure observations at the subduction prism toe},
  journal = {Earth and Planetary Science Letters},
  year = {2011},
  volume = {306},
  number = {3-4},
  pages = {299--305},
  url = {http://dx.doi.org/10.1016/j.epsl.2011.04.017},
  doi = {10.1016/j.epsl.2011.04.017}
}
Deardorff ND, Cashman KV and Chadwick WW (2011), "Observations of eruptive plume dynamics and pyroclastic deposits from submarine explosive eruptions at NW Rota-1, Mariana arc", Journal of Volcanology and Geothermal Research. Vol. 202(1-2), pp. 47-59.
Abstract: Observations at the submarine volcano NW Rota-1, Mariana arc, have provided a unique opportunity to study basaltic explosive eruptions at ˜ 550 m below sea level. In particular, during one week of observations in 2006, the active vent evolved from a region of diffuse gas venting and slow lava effusion to a focused vent that emitted a nearly continuous stream of gas with entrained juvenile pyroclasts. The eruptions were small, strombolian bursts that ejected bomb-sized pyroclasts meters above the vent and produced buoyant plumes that rose tens of meters above the vent and contained variable amounts of ash. Sampled pyroclasts are dominantly coarse ash and lapilli with fluidal textures that provide evidence of magmatic fragmentation. However, the blocky morphologies of some clasts, combined with visual evidence of secondary fragmentation, suggest that quench granulation due to rapid cooling was also important in pyroclast formation. Rapid cooling is also suggested by the slow rise of buoyant plumes (which indicates a low heat content and small density contrast with surrounding seawater). Rapid plume deceleration in seawater limited deposition of coarse ash, lapilli, and bombs to within a few meters of the vent, and allowed recycling of ≤˜15% of the ejected clasts. Petrologic evidence for pyroclast recycling is provided by numerous microcrystalline inclusions incorporated within microlite-poor matrix glass. The matrix glass within these inclusions is strongly enriched in chlorine (
BibTeX:
@article{Deardorff2011,
  author = {Deardorff, N D and Cashman, K V and Chadwick, W W},
  title = {Observations of eruptive plume dynamics and pyroclastic deposits from submarine explosive eruptions at NW Rota-1, Mariana arc},
  journal = {Journal of Volcanology and Geothermal Research},
  year = {2011},
  volume = {202},
  number = {1-2},
  pages = {47--59},
  url = {http://dx.doi.org/10.1016/j.jvolgeores.2011.01.003},
  doi = {10.1016/j.jvolgeores.2011.01.003}
}
Gartman A, Yucel M, Madison AS, Chu DW, Ma S, Janzen CP, Becker EL, Beinart RA, Girguis PR and Luther GW (2011), "Sulfide Oxidation across Diffuse Flow Zones of Hydrothermal Vents", Aquatic Geochemistry. NEW YORK; 233 SPRING ST, NEW YORK, NY 10013 USA, sep, 2011. Vol. 17(4-5), pp. 583-601. SPRINGER.
Abstract: The sulfide (H(2)S/HS(-)) that is emitted from hydrothermal vents begins to oxidize abiotically with oxygen upon contact with ambient bottom water, but the reaction kinetics are slow. Here, using in situ voltammetry, we report detection of the intermediate sulfur oxidation products polysulfides [S(x)(2-)] and thiosulfate [S(2)O(3)(2-)], along with contextual data on sulfide, oxygen, and temperature. At Lau Basin in 2006, thiosulfate was identified in less than one percent of approximately 10,500 scans and no polysulfides were detected. Only five percent of 11,000 voltammetric scans taken at four vent sites at Lau Basin in May 2009 show either thiosulfate or polysulfides. These in situ data indicate that abiotic sulfide oxidation does not readily occur as H(2)S contacts oxic bottom waters. Calculated abiotic potential sulfide oxidation rates are
BibTeX:
@article{Gartman2011,
  author = {Gartman, A and Yucel, M and Madison, A S and Chu, D W and Ma, S and Janzen, C P and Becker, E L and Beinart, R A and Girguis, P R and Luther, G W},
  title = {Sulfide Oxidation across Diffuse Flow Zones of Hydrothermal Vents},
  journal = {Aquatic Geochemistry},
  publisher = {SPRINGER},
  year = {2011},
  volume = {17},
  number = {4-5},
  pages = {583--601},
  doi = {10.1007/s10498-011-9136-1}
}
Gieskes JM, Rathburn AE, Martin JB, Perez ME, Mahn C, Bernhard JM and Day S (2011), "Cold seeps in Monterey Bay, California: Geochemistry of pore waters and relationship to benthic foraminiferal calcite", Applied Geochemistry. Vol. 26(5), pp. 738-746.
Abstract: An extensive geochemical and biogeochemical examination of CH4 seeps in the Clam Flats area of Monterey Bay provides insight into the character of relationships between seep geochemistry and benthic foraminiferal geochemistry. The area is characterized by sulfide-rich fluids. Sulfide increases are associated with large increases in alkalinity, as well as small decreases in dissolved Ca and Mg. In addition, only small increases in NH4 are observed, but values of δ13C of dissolved inorganic C are as low as −60‰ at shallow depths (C of dissolved inorganic C are as low as −60‰ at shallow depths (4, which is transported upward by slow seepage of pore fluids. The geochemistry of the pore fluids should be relevant to the geochemistry of the carbonate tests of living and dead foraminifera. However, a profound disequilibrium of approximately an order of magnitude occurs between the δ13C values of stained (cytoplasm-containing) foraminiferal carbonate and the C isotope values of ambient pore water dissolved inorganic C. Reasons are unclear for this isotopic disequilibrium, but have important implications for interpretations of foraminiferal carbonate as a paleoenvironmental proxy. Much fine scale work is needed to fully understand the relationships between the biogeochemistry of benthic foraminifera and the geochemistry of the pore waters where they live.
BibTeX:
@article{Gieskes2011,
  author = {Gieskes, J M and Rathburn, A E and Martin, J B and Perez, M E and Mahn, C and Bernhard, J M and Day, S},
  title = {Cold seeps in Monterey Bay, California: Geochemistry of pore waters and relationship to benthic foraminiferal calcite},
  journal = {Applied Geochemistry},
  year = {2011},
  volume = {26},
  number = {5},
  pages = {738--746},
  url = {http://dx.doi.org/10.1016/j.apgeochem.2011.01.032},
  doi = {10.1016/j.apgeochem.2011.01.032}
}
Grinar M (2011), "A characterization of a hydrothermal vent community from a diffuse flow vertical wall of "The tower" sulfide edifice at the Juan de Fuca Ridge" Vol. M.S., pp. 48. Temple University.
Abstract: The Juan de Fuca Ridge, located 400 km off the coast of Washington State, is home to unstable and unpredictable hydrothermal vent sites where chemosynthetic communities flourish. In 2007 the manned submersible ALVIN retrieved a Ridgeia piscesae tubeworm community in its entirety from the side of the Tower sulfide edifice from the Endeavor segment of the Juan de Fuca Ridge (47 55.416720 N, 129 6.487020 W, at a depth of 2269 m) using the Bushmaster Jr. collection device. The collection was analyzed for community structure and the data collected were compared to that from several other hydrothermal vent communities. It was determined that substrate composition is a factor that heavily influences community structure. The data were then compared to the community succession model developed by Sarrazin et. al. in 1997 and 1999 (Sarrazin et. al. 1997, Sarrazin and Juniper 1999). The Tower community was found to expand the model as a new community succession classification; that of community iii low flow. The Tower community was then analyzed for diversity, structure and tubeworm morphology in conjunction with two other communities from differing substrata. The Ridgeia piscesae tubeworms were found to be of the "long skinny" morphotype, one that was previously thought to only reside on basaltic substrate. The Tower community has similar species richness and higher species evenness than those from basaltic substrate, but similar richness and lower evenness that those from sulfide. This community type combines the characteristics of those from both substrata, resulting in a community with diversity and structure that is an intermediary between sulfide and basaltic substrates.
BibTeX:
@phdthesis{Grinar2011,
  author = {Grinar, M},
  title = {A characterization of a hydrothermal vent community from a diffuse flow vertical wall of "The tower" sulfide edifice at the Juan de Fuca Ridge},
  publisher = {Temple University},
  year = {2011},
  volume = {M.S.},
  pages = {48},
  url = {http://digital.library.temple.edu/cdm/ref/collection/p245801coll10/id/204453}
}
Gross MG (2011), "Seabed search boost", Current Biology. Vol. 21(3), pp. R94-R95.
Abstract: Oceanography's newest deep-sea research submersible is also its oldest.
BibTeX:
@article{Gross2011,
  author = {Gross, M G},
  title = {Seabed search boost},
  journal = {Current Biology},
  year = {2011},
  volume = {21},
  number = {3},
  pages = {R94--R95},
  url = {http://dx.doi.org/10.1016/j.cub.2011.01.021},
  doi = {10.1016/j.cub.2011.01.021}
}
Luther III GW, Findlay AJ, MacDonald DJ, Owings SM, Hanson TE, Beinart RA and Girguis PR (2011), "Thermodynamics and kinetics of sulfide oxidation by oxygen: a look at inorganically controlled reactions and biologically mediated processes in the environment", FRONTIERS IN MICROBIOLOGY. Vol. 2
Abstract: The thermodynamics for the first electron transfer step for sulfide and
oxygen indicates that the reaction is unfavorable as unstable superoxide
and bisulfide radical ions would need to be produced. However, a
two-electron transfer is favorable as stable S(0) and peroxide would be
formed, but the partially filled orbitals in oxygen that accept
electrons prevent rapid kinetics. Abiotic sulfide oxidation kinetics
improve when reduced iron and/or manganese are oxidized by oxygen to
form oxidized metals which in turn oxidize sulfide. Biological sulfur
oxidation relies on enzymes that have evolved to overcome these kinetic
constraints to affect rapid sulfide oxidation. Here we review the
available thermodynamic and kinetic data for H2S and HS center dot as
well as O-2, reactive oxygen species, nitrate, nitrite, and NOx species.
We also present new kinetic data for abiotic sulfide oxidation with
oxygen in trace metal clean solutions that constrain abiotic rates of
sulfide oxidation in metal free solution and agree with the kinetic and
thermodynamic calculations. Moreover, we present experimental data that
give insight on rates of chemolithotrophic and photolithotrophic sulfide
oxidation in the environment. We demonstrate that both anaerobic
photolithotrophic and aerobic chemolithotrophic sulfide oxidation rates
are three or more orders of magnitude higher than abiotic rates
suggesting that in most environments biotic sulfide oxidation rates will
far exceed abiotic rates due to the thermodynamic and kinetic
constraints discussed in the first section of the paper. Such data
reshape our thinking about the biotic and abiotic contributions to
sulfide oxidation in the environment.
BibTeX:
@article{ISI:000208863500072,
  author = {Luther III, George W and Findlay, Alyssa J and MacDonald, Daniel J and Owings, Shannon M and Hanson, Thomas E and Beinart, Roxanne A and Girguis, Peter R},
  title = {Thermodynamics and kinetics of sulfide oxidation by oxygen: a look at inorganically controlled reactions and biologically mediated processes in the environment},
  journal = {FRONTIERS IN MICROBIOLOGY},
  year = {2011},
  volume = {2},
  doi = {10.3389/fmicb.2011.00062}
}
Simpson A and Watling L (2011), "Precious corals (Coralliidae) from north-western Atlantic Seamounts", JOURNAL OF THE MARINE BIOLOGICAL ASSOCIATION OF THE UNITED KINGDOM., mar, 2011. Vol. 91(2, SI), pp. 369-382.
Abstract: Two new species belonging to the precious coral genus Corallium were
collected during a series of exploratory cruises to the New England and
Corner Rise Seamounts in 2003-2005. One red species, Corallium
bathyrubrum sp. nov., and one white species, C. bayeri sp. nov., are
described. Corallium bathyrubrum is the first red Corallium to be
reported from the western Atlantic. An additional species, C. niobe
Bayer, 1964 originally described from the Straits of Florida, was also
collected and its description augmented.
BibTeX:
@article{ISI:000287940400009,
  author = {Simpson, Anne and Watling, Les},
  title = {Precious corals (Coralliidae) from north-western Atlantic Seamounts},
  journal = {JOURNAL OF THE MARINE BIOLOGICAL ASSOCIATION OF THE UNITED KINGDOM},
  year = {2011},
  volume = {91},
  number = {2, SI},
  pages = {369--382},
  doi = {10.1017/S002531541000086X}
}
Xie W, Wang F, Guo L, Chen Z, Sievert SM, Meng J, Huang G, Li Y, Yan Q, Wu S, Wang X, Chen S, He G, Xiao X and Xu A (2011), "Comparative metagenomics of microbial communities inhabiting deep-sea hydrothermal vent chimneys with contrasting chemistries", ISME JOURNAL., mar, 2011. Vol. 5(3), pp. 414-426.
Abstract: Deep-sea hydrothermal vent chimneys harbor a high diversity of largely
unknown microorganisms. Although the phylogenetic diversity of these
microorganisms has been described previously, the adaptation and
metabolic potential of the microbial communities is only beginning to be
revealed. A pyrosequencing approach was used to directly obtain
sequences from a fosmid library constructed from a black smoker chimney
4143-1 in the Mothra hydrothermal vent field at the Juan de Fuca Ridge.
A total of 308 034 reads with an average sequence length of 227 bp were
generated. Comparative genomic analyses of metagenomes from a variety of
environments by two-way clustering of samples and functional gene
categories demonstrated that the 4143-1 metagenome clustered most
closely with that from a carbonate chimney from Lost City. Both are
highly enriched in genes for mismatch repair and homologous
recombination, suggesting that the microbial communities have evolved
extensive DNA repair systems to cope with the extreme conditions that
have potential deleterious effects on the genomes. As previously
reported for the Lost City microbiome, the metagenome of chimney 4143-1
exhibited a high proportion of transposases, implying that horizontal
gene transfer may be a common occurrence in the deep-sea vent chimney
biosphere. In addition, genes for chemotaxis and flagellar assembly were
highly enriched in the chimney metagenomes, reflecting the adaptation of
the organisms to the highly dynamic conditions present within the
chimney walls. Reconstruction of the metabolic pathways revealed that
the microbial community in the wall of chimney 4143-1 was mainly fueled
by sulfur oxidation, putatively coupled to nitrate reduction to perform
inorganic carbon fixation through the Calvin-Benson-Bassham cycle. On
the basis of the genomic organization of the key genes of the carbon
fixation and sulfur oxidation pathways contained in the large genomic
fragments, both obligate and facultative autotrophs appear to be present
and contribute to biomass production. The ISME Journal (2011) 5,
414-426; doi: 10.1038/ismej.2010.144; published online 7 October 2010
BibTeX:
@article{ISI:000290021000005,
  author = {Xie, Wei and Wang, Fengping and Guo, Lei and Chen, Zeling and Sievert, Stefan M and Meng, Jun and Huang, Guangrui and Li, Yuxin and Yan, Qingyu and Wu, Shan and Wang, Xin and Chen, Shangwu and He, Guangyuan and Xiao, Xiang and Xu, Anlong},
  title = {Comparative metagenomics of microbial communities inhabiting deep-sea hydrothermal vent chimneys with contrasting chemistries},
  journal = {ISME JOURNAL},
  year = {2011},
  volume = {5},
  number = {3},
  pages = {414--426},
  doi = {10.1038/ismej.2010.144}
}
Eichinger I, Klepal W, Schmid M and Bright M (2011), "Organization and Microanatomy of the Sclerolinum contortum Trophosome (Polychaeta, Siboglinidae)", BIOLOGICAL BULLETIN., apr, 2011. Vol. 220(2), pp. 140-153.
Abstract: The trophosome-an organ especially evolved to accommodate symbiotic
bacteria-is a key character of the polychaete family Siboglinidae.
Astonishingly, the trophosomes vary in organization and origin between
the different siboglinid taxa. The trophosome of the small genus
Sclerolinum was nearly unknown until now. Here we investigated the
trophosome of S. contortum from the Gulf of Mexico, using light and
electron microscopy. We show that this organ derives from the visceral
mesoderm and propose that the trophosome of the sister clade
Vestimentifera and Sclerolinum is a homologous character. Like that of
juvenile vestimentiferans, the trophosome of Sclerolinum trophosome is
simply organized. This study reveals that the Sclerolinum trophosome
exhibits two regions that differ in the organization of host tissue and
the size and shape of the symbionts. We suggest that a specific cell
cycle within the symbiont-housing organ is directed along the
longitudinal body axis, with a region of proliferation anteriorly and a
region of degradation posteriorly. Using Raman microspectroscopy we
demonstrate that the endosymbionts of S. contortum from the Gulf of
Mexico contain sulfur vesicles, and we argue for a chemoautotrophic
sulfur-oxidizing metabolism.
BibTeX:
@article{ISI:000290596200008,
  author = {Eichinger, Irmgard and Klepal, Waltraud and Schmid, Markus and Bright, Monika},
  title = {Organization and Microanatomy of the Sclerolinum contortum Trophosome (Polychaeta, Siboglinidae)},
  journal = {BIOLOGICAL BULLETIN},
  year = {2011},
  volume = {220},
  number = {2},
  pages = {140--153}
}
Anderson RE, Brazelton WJ and Baross JA (2011), "Using CRISPRs as a metagenomic tool to identify microbial hosts of a diffuse flow hydrothermal vent viral assemblage", FEMS MICROBIOLOGY ECOLOGY., jul, 2011. Vol. 77(1), pp. 120-133.
Abstract: Metagenomic analyses of viruses have revealed widespread diversity in
the viriosphere, but it remains a challenge to identify specific hosts
for a viral assemblage. To address this problem, we analyze the viral
metagenome of a northeast Pacific hydrothermal vent with a comprehensive
database of spacers derived from the clustered regularly interspaced
short palindromic repeat (CRISPR) putative immune system. CRISPR spacer
matches to the marine vent virome suggest that viruses infecting hosts
from diverse taxonomic groups are present in this vent environment.
Comparative virome analyses show that CRISPR spacers from vent isolates
and from thermophiles in general have a higher percentage of matches to
the vent virome than to other marine or terrestrial hot spring viromes.
However, a high percentage of hits to spacers from mesophilic hosts,
combined with a moderately high modeled alpha diversity, suggest that
the marine vent virome is comprised of viruses that have the potential
to infect diverse taxonomic groups of multiple thermal regimes in both
the bacterial and the archaeal domains.
BibTeX:
@article{ISI:000291312500011,
  author = {Anderson, Rika E and Brazelton, William J and Baross, John A},
  title = {Using CRISPRs as a metagenomic tool to identify microbial hosts of a diffuse flow hydrothermal vent viral assemblage},
  journal = {FEMS MICROBIOLOGY ECOLOGY},
  year = {2011},
  volume = {77},
  number = {1},
  pages = {120--133},
  doi = {10.1111/j.1574-6941.2011.01090.x}
}
Gennerich H-H and Villinger H (2011), "Deciphering the ocean bottom pressure variation in the Logatchev hydrothermal field at the eastern flank of the Mid-Atlantic Ridge", GEOCHEMISTRY GEOPHYSICS GEOSYSTEMS., jul, 2011. Vol. 12
Abstract: Ocean bottom pressure data from the Logatchev hydrothermal field (LHF)
are presented and analyzed. The data were collected with two ocean
bottom pressure meters (OBPs), constructed at the University of Bremen,
that are capable of recording signals with frequencies up to 0.25 Hz.
Over the long-term, a nearly 2.5 kPa (25 cm water column equivalent)
pressure variation over 3.7 years is observed, which is consistent with
uplift followed by subsidence, but cannot unequivocally be discerned
from instrumental drift. Medium-term pressure variations are compared
with satellite surface topography, satellite gravity, ocean modeling,
and in situ data from an OBP 700 km away. It is shown that fluctuations
in the oceanic mass distribution dominate the variations in this
frequency range and that oceanic modeling and data from a 700 km distant
OBP are positively correlated with the LHF bottom pressure time series.
The short-term variations are dominated by microseisms originating from
sea surface waves and pressure waves from earthquakes as can be shown by
comparison with weather buoy and teleseismic data.
BibTeX:
@article{ISI:000292610200001,
  author = {Gennerich, Hans-Hermann and Villinger, Heinrich},
  title = {Deciphering the ocean bottom pressure variation in the Logatchev hydrothermal field at the eastern flank of the Mid-Atlantic Ridge},
  journal = {GEOCHEMISTRY GEOPHYSICS GEOSYSTEMS},
  year = {2011},
  volume = {12},
  doi = {10.1029/2010GC003441}
}
Williams GC and Alderslade P (2011), "Three new species of pennatulacean octocorals with the ability to attach to rocky substrata (Cnidaria: Anthozoa: Pennatulacea)", ZOOTAXA., aug, 2011. (3001), pp. 33-48.
Abstract: All sea pens have been thought to anchor in soft sediment using a basal,
sausage-shaped, muscular peduncle. Based on underwater images and
examination of specimens, we report an adaptation of the proximal
portion of the peduncle for attachment to solid surfaces. We document
four species with this adaptation, three new, Anthoptilum lithophilum
sp. nov. (California, 669-700 m), A. gowlettholmesae sp. nov. (Tasmania,
729-1803 m), and Calibelemnon francei sp. nov. (the Bahamas, 1969 m),
and one known, A. decipiens Thomson & Henderson, 1906 (Sri Lanka, 925
m). The peduncle of a colony with this adaptation is greatly expanded by
an outgrowth of the coenenchyme that forms a sucker-like structure,
beneath which a conical mass of tough tissue surrounds the proximal end
of the internal axis. We infer this structure affects suction,
increasing or decreasing the strength of adhesion to the substratum, and
discuss the systematics and functional morphology of this new ecological
phenomenon-pennatulaceans fastened to hard substrata. We alter the
definition of the genus Anthoptilum to accommodate this morphology,
reporting on specimens of the type species, A. grandiflorum; compare the
two sea pen families-Anthoptilidae and Scleroptilidae- and the two
genera; and present a key to the known rock-inhabiting species.
BibTeX:
@article{ISI:000294119400002,
  author = {Williams, Gary C and Alderslade, Philip},
  title = {Three new species of pennatulacean octocorals with the ability to attach to rocky substrata (Cnidaria: Anthozoa: Pennatulacea)},
  journal = {ZOOTAXA},
  year = {2011},
  number = {3001},
  pages = {33--48}
}
Zielinski FU, Gennerich H-H, Borowski C, Wenzhoefer F and Dubilier N (2011), "In situ measurements of hydrogen sulfide, oxygen, and temperature in diffuse fluids of an ultramafic-hosted hydrothermal vent field (Logatchev, 14 degrees 45 ` N, Mid-Atlantic Ridge): Implications for chemosymbiotic bathymodiolin mussels", GEOCHEMISTRY GEOPHYSICS GEOSYSTEMS., sep, 2011. Vol. 12
Abstract: The Logatchev hydrothermal vent field (14 degrees 45'N, Mid-Atlantic
Ridge) is located in a ridge segment characterized by mantle-derived
ultramafic outcrops. Compared to basalt-hosted vents, Logatchev
high-temperature fluids are relatively low in sulfide indicating that
the diffuse, low-temperature fluids of this vent field may not contain
sufficient sulfide concentrations to support a chemosymbiotic
invertebrate community. However, the high abundances of bathymodiolin
mussels with bacterial symbionts related to free-living sulfur-oxidizing
bacteria suggested that bioavailable sulfide is present at Logatchev. To
clarify, if diffuse fluids above mussel beds of Bathymodiolus
puteoserpentis provide the reductants and oxidants needed by their
symbionts for aerobic sulfide oxidation, in situ microsensor
measurements of dissolved hydrogen sulfide and oxygen were combined with
simultaneous temperature measurements. High temporal fluctuations of all
three parameters were measured above the mussel beds. H2S and O-2
coexisted with mean concentrations between 9 and 31 mu M (H2S) and 216
and 228 mu M (O-2). Temperature maxima (textless= 7.4 degrees C) were generally
concurrent with H2S maxima (textless= 156 mu M) and O-2 minima (textgreater= 142 mu M).
Long-term measurements for 250 days using temperature as a proxy for
oxygen and sulfide concentrations indicated that the mussels were
neither oxygen limited nor sulfide limited. Our in situ measurements at
Logatchev indicate that sulfide may also be bioavailable in diffuse
fluids from other ultramafic-hosted vents along slow and ultraslow
spreading ridges.
Components: 12,100 words, 9 figures, 4 tables.
BibTeX:
@article{ISI:000295134600001,
  author = {Zielinski, Frank U and Gennerich, Hans-Hermann and Borowski, Christian and Wenzhoefer, Frank and Dubilier, Nicole},
  title = {In situ measurements of hydrogen sulfide, oxygen, and temperature in diffuse fluids of an ultramafic-hosted hydrothermal vent field (Logatchev, 14 degrees 45 ` N, Mid-Atlantic Ridge): Implications for chemosymbiotic bathymodiolin mussels},
  journal = {GEOCHEMISTRY GEOPHYSICS GEOSYSTEMS},
  year = {2011},
  volume = {12},
  doi = {10.1029/2011GC003632}
}
Xu G and Di Iorio D (2011), "The relative effects of particles and turbulence on acoustic scattering from deep-sea hydrothermal vent plumes", JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA., oct, 2011. Vol. 130(4, 1), pp. 1856-1867.
Abstract: Acoustic methods are applied to the investigation and monitoring of a
vigorous hydrothermal plume within the Main Endeavor vent field at the
Endeavor segment of the Juan de Fuca Ridge. Forward propagation and
scattering from suspended particulates using Rayleigh scattering theory
is shown to be negligible (log-amplitude variance sigma(2)(chi) similar
to 10(-7)) compared to turbulence induced by temperature fluctuations
(sigma(2)(chi) similar to 0.1). The backscattering from turbulence is
then quantified using the forward scattering derived turbulence level,
which gives a volume backscattering strength of s(V) = 6.5 x 10(-8)
m(-1). The volume backscattering cross section from particulates can
range from s(V) = 3.3 x 10(-6) to 7.2 x 10(-10) m(-1) depending on the
particle size. These results show that forward scatter acoustic methods
in hydrothermal vent applications can be used to quantify turbulence and
its effect on backscatter measurements, which can be a dominant factor
depending on the particle size and its location within the plume. (C)
2011 Acoustical Society of America. [DOI: 10.1121/1.3624816]
BibTeX:
@article{ISI:000295799400034,
  author = {Xu, Guangyu and Di Iorio, Daniela},
  title = {The relative effects of particles and turbulence on acoustic scattering from deep-sea hydrothermal vent plumes},
  journal = {JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA},
  year = {2011},
  volume = {130},
  number = {4, 1},
  pages = {1856--1867},
  doi = {10.1121/1.3624816}
}
Schauer R, Roy H, Augustin N, Gennerich H-H, Peters M, Wenzhoefer F, Amann R and Meyerdierks A (2011), "Bacterial sulfur cycling shapes microbial communities in surface sediments of an ultramafic hydrothermal vent field", ENVIRONMENTAL MICROBIOLOGY., oct, 2011. Vol. 13(10), pp. 2633-2648.
Abstract: The ultramafic-hosted Logatchev hydrothermal field (LHF) is
characterized by vent fluids, which are enriched in dissolved hydrogen
and methane compared with fluids from basalt-hosted systems. Thick
sediment layers in LHF are partly covered by characteristic white mats.
In this study, these sediments were investigated in order to determine
biogeochemical processes and key organisms relevant for primary
production. Temperature profiling at two mat-covered sites showed a
conductive heating of the sediments. Elemental sulfur was detected in
the overlying mat and metal-sulfides in the upper sediment layer.
Micro-profiles revealed an intensive hydrogen sulfide flux from deeper
sediment layers. Fluorescence in situ hybridization showed that
filamentous and vibrioid, Arcobacter-related Epsilonproteobacteria
dominated the overlying mats. This is in contrast to sulfidic sediments
in basalt-hosted fields where mats of similar appearance are composed of
large sulfur-oxidizing Gammaproteobacteria. Epsilonproteobacteria
(7-21%) and Deltaproteobacteria (20-21%) were highly abundant in the
surface sediment layer. The physiology of the closest cultivated
relatives, revealed by comparative 16S rRNA sequence analysis, was
characterized by the capability to metabolize sulfur components. High
sulfate reduction rates as well as sulfide depleted in (34)S further
confirmed the importance of the biogeochemical sulfur cycle. In
contrast, methane was found to be of minor relevance for microbial life
in mat-covered surface sediments. Our data indicate that in conductively
heated surface sediments microbial sulfur cycling is the driving force
for bacterial biomass production although ultramafichosted systems are
characterized by fluids with high levels of dissolved methane and
hydrogen.
BibTeX:
@article{ISI:000295971300003,
  author = {Schauer, Regina and Roy, Hans and Augustin, Nico and Gennerich, Hans-Hermann and Peters, Marc and Wenzhoefer, Frank and Amann, Rudolf and Meyerdierks, Anke},
  title = {Bacterial sulfur cycling shapes microbial communities in surface sediments of an ultramafic hydrothermal vent field},
  journal = {ENVIRONMENTAL MICROBIOLOGY},
  year = {2011},
  volume = {13},
  number = {10},
  pages = {2633--2648},
  doi = {10.1111/j.1462-2920.2011.02530.x}
}
Thresher RE, Adkins J, Fallon SJ, Gowlett-Holmes K, Althaus F and Williams A (2011), "Extraordinarily high biomass benthic community on Southern Ocean seamounts", SCIENTIFIC REPORTS., oct, 2011. Vol. 1
Abstract: We describe a previously unknown assemblage of seamount-associated megabenthos that has by far the highest peak biomass reported in the deep-sea outside of vent communities. The assemblage was found at depths of 2-2.5 km on rocky geomorphic features off the southeast coast of Australia, in an area near the Sub-Antarctic Zone characterised by high rates of surface productivity and carbon export to the deep-ocean. These conditions, and the taxa in the assemblage, are widely distributed around the Southern mid-latitudes, suggesting the high-biomass assemblage is also likely to be widespread. The role of this assemblage in regional ecosystem and carbon dynamics and its sensitivities to anthropogenic impacts are unknown. The discovery highlights the lack of information on deep-sea biota worldwide and the potential for unanticipated impacts of deep-sea exploitation.
BibTeX:
@article{ISI:000296056300001,
  author = {Thresher, R E and Adkins, J and Fallon, S J and Gowlett-Holmes, K and Althaus, F and Williams, A},
  title = {Extraordinarily high biomass benthic community on Southern Ocean seamounts},
  journal = {SCIENTIFIC REPORTS},
  year = {2011},
  volume = {1},
  doi = {10.1038/srep00119}
}
Thresher RE, Adkins J and Thiagarajan N (2011), "Modal analysis of the deep-water solitary scleractinian, Desmophyllum dianthus, on SW Pacific seamounts: inferred recruitment periodicity, growth, and mortality rates", CORAL REEFS., dec, 2011. Vol. 30(4), pp. 1063-1070.
Abstract: Little is known about the demography of corals inhabiting deep-sea features due to the logistical difficulties of working at the extreme depths they inhabit. To obtain basic information about growth, mortality, and recruitment dynamics for such a coral, we applied modal analysis to the size frequency distributions of live-caught and sub-fossil specimens of the widely distributed solitary cup coral, Desmophyllum dianthus, collected on SW Pacific seamounts. Comparison of live-caught material collected in 1997 and 2007-2009 indicated modal progression over time and an implied maximum age of approximately 190 years, which is similar to ages determined previously for D. dianthus using radiometric techniques. A log-linear decline in the number of individuals with increasing size further implies a constant adult mortality rate, of 15.1% per annum in 1997 and 9.2% per annum in 2007-2009. The spacing of size modes in the 2007-2009 samples suggests regularly episodic recruitment events, at 22- to 32-year intervals, which may relate to periodic variability in large-scale Southern Ocean circulation. Preliminary analyses of size frequency distributions of the sub-fossil material suggest that the trophodynamics, growth, and adult mortality schedules of D. dianthus in the SW Pacific have remained basically similar throughout the Holocene.
BibTeX:
@article{ISI:000296085300022,
  author = {Thresher, R E and Adkins, J and Thiagarajan, N},
  title = {Modal analysis of the deep-water solitary scleractinian, Desmophyllum dianthus, on SW Pacific seamounts: inferred recruitment periodicity, growth, and mortality rates},
  journal = {CORAL REEFS},
  year = {2011},
  volume = {30},
  number = {4},
  pages = {1063--1070},
  doi = {10.1007/s00338-011-0806-7}
}
Thresher RE, Tilbrook B, Fallon S, Wilson NC and Adkins J (2011), "Effects of chronic low carbonate saturation levels on the distribution, growth and skeletal chemistry of deep-sea corals and other seamount megabenthos", MARINE ECOLOGY PROGRESS SERIES. Vol. 442, pp. 87-99.
Abstract: Ocean acidification has been predicted to reduce the ability of marine organisms to produce carbonate skeletons, threatening their long-term viability and severely impacting marine ecosystems. Corals, as ecosystem engineers, have been identified as particularly vulnerable and important. To determine the sensitivity of corals and allied taxa to long-term exposure to very low carbonate concentrations, we examined the distribution and skeletal characteristics of coral taxa along a natural deep-sea concentration gradient on seamounts of SW Australia. Carbonate under-saturation had little evident effect on the depth distribution, growth or skeletal composition of live scleractinians or gorgonians, with corals growing, often abundantly, in waters as much as 20 to 30% under-saturated. Developmental anomalies in the deepest skeleton-forming anthozoan collected (an isidid gorgonian, at nearly 4 km depth) suggest an absolute low tolerance limit of about 40% under-saturation. Evidence for an effect of acidification on the accumulation of reef structure is ambiguous, with clear indications of dissolution of high-magnesium calcite (HMC) gorgonian skeletons at depths below 2300 m, but also abundant, old scleractinian skeletons well below the aragonite saturation horizon. The latter might be the result of ferromanganese deposition on exposed skeletons, which, however, may render them inhospitable for benthic organisms.
BibTeX:
@article{ISI:000298301200007,
  author = {Thresher, Ronald E and Tilbrook, Bronte and Fallon, Stewart and Wilson, Nick C and Adkins, Jess},
  title = {Effects of chronic low carbonate saturation levels on the distribution, growth and skeletal chemistry of deep-sea corals and other seamount megabenthos},
  journal = {MARINE ECOLOGY PROGRESS SERIES},
  year = {2011},
  volume = {442},
  pages = {87--99},
  doi = {10.3354/meps09400}
}
Holler T, Widdel F, Knittel K, Amann R, Kellermann MY, Hinrichs K-U, Teske A, Boetius A and Wegener G (2011), "Thermophilic anaerobic oxidation of methane by marine microbial consortia", ISME JOURNAL., dec, 2011. Vol. 5(12), pp. 1946-1956.
Abstract: The anaerobic oxidation of methane (AOM) with sulfate controls the
emission of the greenhouse gas methane from the ocean floor. AOM is
performed by microbial consortia of archaea (ANME) associated with
partners related to sulfate-reducing bacteria. In vitro enrichments of
AOM were so far only successful at temperatures textless= 25 degrees C;
however, energy gain for growth by AOM with sulfate is in principle also
possible at higher temperatures. Sequences of 16S rRNA genes and core
lipids characteristic for ANME as well as hints of in situ AOM activity
were indeed reported for geothermally heated marine environments, yet no
direct evidence for thermophilic growth of marine ANME consortia was
obtained to date. To study possible thermophilic AOM, we investigated
hydrothermally influenced sediment from the Guaymas Basin. In vitro
incubations showed activity of sulfate-dependent methane oxidation
between 5 and 70 degrees C with an apparent optimum between 45 and 60
degrees C. AOM was absent at temperatures textgreater= 75 degrees C. Long-term
enrichment of AOM was fastest at 50 degrees C, yielding a 13-fold
increase of methane-dependent sulfate reduction within 250 days,
equivalent to an apparent doubling time of 68 days. The enrichments were
dominated by novel ANME-1 consortia, mostly associated with bacterial
partners of the deltaproteobacterial HotSeep-1 cluster, a deeply
branching phylogenetic group previously found in a butane-amended 60
degrees C-enrichment culture of Guaymas sediments. The closest relatives
(Desulfurella spp.; Hippea maritima) are moderately thermophilic sulfur
reducers. Results indicate that AOM and ANME archaea could be of
biogeochemical relevance not only in cold to moderate but also in hot
marine habitats. The ISME Journal (2011) 5, 1946-1956; doi:
10.1038/ismej.2011.77; published online 23 June 2011
BibTeX:
@article{ISI:000299052400011,
  author = {Holler, Thomas and Widdel, Friedrich and Knittel, Katrin and Amann, Rudolf and Kellermann, Matthias Y and Hinrichs, Kai-Uwe and Teske, Andreas and Boetius, Antje and Wegener, Gunter},
  title = {Thermophilic anaerobic oxidation of methane by marine microbial consortia},
  journal = {ISME JOURNAL},
  year = {2011},
  volume = {5},
  number = {12},
  pages = {1946--1956},
  doi = {10.1038/ismej.2011.77}
}
Teresa Aguado M and Rouse GW (2011), "Nautiliniellidae (Annelida) from Costa Rican cold seeps and a western Pacific hydrothermal vent, with description of four new species", SYSTEMATICS AND BIODIVERSITY. Vol. 9(2), pp. 109-131.
Abstract: Four genera and five species of Nautiliniellidae (Phyllodocida;
Annelida), representing four new species and one new record, were found
in association with bivalves belonging to Mytilidae (Bathymodiolus
spp.), Solemyidae (Acharax sp.) and Vesicomyidae (Calyptogena and
Vesicomya) from hydrothermal vents of the western Pacific (Lau back-arc
basin) and cold seeps of the eastern Pacific (Costa Rica).
Iheyomytilidicola lauensis n. sp. is characterized by the presence of
unidentate hooks; Laubierus alvini n. sp. has long dorsal cirri and
notoacicula not protruding in any segment; Natsushima sashai n. sp has
bifurcate chaetae with distal teeth markedly different in length and
width between each other; and Shinkai fontefridae n. sp. differs in
having posterior hooks with subdistal spines. Sexual dimorphism is
described for Shinkai and Natsushima species and confirmed by DNA
sequencing (Cytochrome c oxidase subunit I sequences). In addition, one
specimen of N. bifurcata Miura & Laubier, 1990 from the Gulf of Cadiz
has been studied to compare it morphologically and genetically with N.
sashai n. sp. Scanning electron and optical microscopy images are
provided for each species, as well as pictures of live animals.
Morphological features described and documented for the first time
include the presence of internal longitudinal chambers within chaetae
and possible evidence that the simple chaetae, characteristic of
nautiliniellids, may be derived from compound chaetae.
BibTeX:
@article{ISI:000299425400001,
  author = {Teresa Aguado, M and Rouse, Greg W},
  title = {Nautiliniellidae (Annelida) from Costa Rican cold seeps and a western Pacific hydrothermal vent, with description of four new species},
  journal = {SYSTEMATICS AND BIODIVERSITY},
  year = {2011},
  volume = {9},
  number = {2},
  pages = {109--131},
  doi = {10.1080/14772000.2011.569033}
}
Kinsey JC, Yoerger DR, Jakuba MV, Camilli R, Fisher CR and German CR (2011), "Assessing the Deepwater Horizon oil spill with the Sentry autonomous underwater vehicle", 2011 IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS). , pp. 261-267.
Abstract: This paper reports the Sentry autonomous underwater vehicle and its deployment on two cruises in response to the Deepwater Horizon oil spill. The first cruise, in June 2010, coupled Sentry with the TETHYS mass spectrometer to track and localize a subsea hydrocarbon plume at a depth of approximately 1100m going at least 30km from the oil spill site. In December 2010, Sentry mapped and photographed deep-sea biological communities for follow-up observations and sampling with the Alvin manned submersible. These cruises demonstrate how robots and novel sensing technologies contributed to the oil spill assessment and the broader impact of technologies developed for basic research.
BibTeX:
@article{Kinsey2011,
  author = {Kinsey, J C and Yoerger, D R and Jakuba, M V and Camilli, Rich and Fisher, C R and German, C R},
  title = {Assessing the Deepwater Horizon oil spill with the Sentry autonomous underwater vehicle},
  journal = {2011 IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS)},
  year = {2011},
  pages = {261--267},
  doi = {10.1109/IROS.2011.6095008}
}
Li J, Zhou HY, Peng XT, Fu M, Chen ZQ and Yao HQ (2011), "Abundance and distribution of fatty acids within the walls of an active deep-sea sulfide chimney", Journal of Sea Research. Vol. 65(3), pp. 333-339.
Abstract: Abundance and distribution of total fatty acids (TFAs) were examined along the physicochemical gradient within an active hydrothermal chimney collected from the Main Endeavour segment of Juan de Fuca Ridge. Approximately 27 fatty acids are identified with a chain-length ranging from C12 to C22. From the exterior to the interior of the chimney walls, the total concentrations of TFAs (∑ TFAs) show a trend of evident decrease. The observed compositions of TFAs are rich in bacterial biomarkers especially monounsaturated fatty acids (MUFAs) and minor branched and cyclopropyl FAs. On the basis of the species-specific FAs and bacterial 16SrRNA gene analysis (Li et al., unpublished data), sulfur-based metabolism appears to be the essential metabolic process in the chimney. Furthermore, the sulfur oxidizing bacteria (SOB) are identified as a basic component of microbial communities at the exterior of the hydrothermal chimney, and its proportion shows an inward decrease while the sulfate reducing bacteria (SRB) have an inverse distribution.
BibTeX:
@article{Li2011,
  author = {Li, J and Zhou, H Y and Peng, X T and Fu, M and Chen, Z Q and Yao, H Q},
  title = {Abundance and distribution of fatty acids within the walls of an active deep-sea sulfide chimney},
  journal = {Journal of Sea Research},
  year = {2011},
  volume = {65},
  number = {3},
  pages = {333--339},
  url = {http://dx.doi.org/10.1016/j.seares.2011.01.005},
  doi = {10.1016/j.seares.2011.01.005}
}
Ludwig KA, Shen CC, Kelley DS, Cheng H and Edwards RL (2011), "U-Th systematics and ages of carbonate chimneys at the Lost City Hydrothermal Field", Geochimica et Cosmochimica Acta. Vol. 75(7), pp. 1869-1888.
Abstract: The Lost City Hydrothermal Field (LCHF) is a serpentinite-hosted vent field located 15 km west of the spreading axis of the Mid-Atlantic Ridge. In this study, uranium–thorium (U–Th) geochronological techniques have been used to examine the U–Th systematics of hydrothermal fluids and the 230Th ages of hydrothermally-precipitated carbonate chimneys at the LCHF. Fluid sample analyses indicate that endmember fluids likely contain only 0.0073 ng/g U or less compared to 3.28 ± 0.03 ng/g of U in ambient seawater. For fluid samples containing only 2–21% ambient seawater (1.1–11 mmol/kg Mg), Th concentration is 0.11–0.13 pg/g and surrounding seawater concentrations average 0.133 ± 0.016 pg/g. The 230Th/232Th atomic ratios of the vent fluids range from 1 (±10) × 10−6 to 11 (±5) × 10−6, are less than those of seawater, and indicate that the vent fluids may contribute a minor amount of non-radiogenic 230Th to the LCHF carbonate chimney deposits. Chimney 238U concentrations range from 1 to 10 μg/g and the average chimney corrected initial δ234U is 147.2 ± 0.8, which is not significantly different from the ambient seawater value of 146.5 ± 0.6. Carbonate 232Th concentrations range broadly from 0.0038 ± 0.0003 to 125 ± 16 ng/g and 230Th/232Th atomic ratios vary from near seawater values of 43 (±8) × 10−6 up to 530 (±25) × 10−3. Chimney ages, corrected for initial 230Th, range from 17 ± 6 yrs to 120 ± 13 kyrs. The youngest chimneys are at the intersection of two active, steeply-dipping normal faults that cut the Atlantis Massif; the oldest chimneys are located in the southwest portion of the field. Vent deposits on a steep, fault-bounded wall on the east side of the field are all Th, range from 17 ± 6 yrs to 120 ± 13 kyrs. The youngest chimneys are at the intersection of two active, steeply-dipping normal faults that cut the Atlantis Massif; the oldest chimneys are located in the southwest portion of the field. Vent deposits on a steep, fault-bounded wall on the east side of the field are all
BibTeX:
@article{Ludwig2011,
  author = {Ludwig, K A and Shen, C C and Kelley, D S and Cheng, H and Edwards, R L},
  title = {U-Th systematics and ages of carbonate chimneys at the Lost City Hydrothermal Field},
  journal = {Geochimica et Cosmochimica Acta},
  year = {2011},
  volume = {75},
  number = {7},
  pages = {1869--1888},
  url = {http://dx.doi.org/10.1016/j.gca.2011.01.008},
  doi = {10.1016/j.gca.2011.01.008}
}
Luther GW, Findlay AJ, MacDonald DJ, Owings SM, Hanson TE, Beinart RA and Girguis PR (2011), "Thermodynamics and kinetics of sulfide oxidation by oxygen: a look at inorganically controlled reactions and biologically mediated processes in the environment", Frontiers in Microbiology. LAUSANNE; PO BOX 110, LAUSANNE, 1015, SWITZERLAND Vol. 2, pp. 62. FRONTIERS RESEARCH FOUNDATION.
Abstract: The thermodynamics for the first electron transfer step for sulfide and oxygen indicates that the reaction is unfavorable as unstable superoxide and bisulfide radical ions would need to be produced. However, a two-electron transfer is favorable as stable S(0) and peroxide would be formed, but the partially filled orbitals in oxygen that accept electrons prevent rapid kinetics. Abiotic sulfide oxidation kinetics improve when reduced iron and/or manganese are oxidized by oxygen to form oxidized metals which in turn oxidize sulfide. Biological sulfur oxidation relies on enzymes that have evolved to overcome these kinetic constraints to affect rapid sulfide oxidation. Here we review the available thermodynamic and kinetic data for H2S and HS center dot as well as O-2, reactive oxygen species, nitrate, nitrite, and NOx species. We also present new kinetic data for abiotic sulfide oxidation with oxygen in trace metal clean solutions that constrain abiotic rates of sulfide oxidation in metal free solution and agree with the kinetic and thermodynamic calculations. Moreover, we present experimental data that give insight on rates of chemolithotrophic and photolithotrophic sulfide oxidation in the environment. We demonstrate that both anaerobic photolithotrophic and aerobic chemolithotrophic sulfide oxidation rates are three or more orders of magnitude higher than abiotic rates suggesting that in most environments biotic sulfide oxidation rates will far exceed abiotic rates due to the thermodynamic and kinetic constraints discussed in the first section of the paper. Such data reshape our thinking about the biotic and abiotic contributions to sulfide oxidation in the environment.
BibTeX:
@article{Luther2011,
  author = {Luther, G W and Findlay, A J and MacDonald, D J and Owings, S M and Hanson, T E and Beinart, R A and Girguis, P R},
  title = {Thermodynamics and kinetics of sulfide oxidation by oxygen: a look at inorganically controlled reactions and biologically mediated processes in the environment},
  journal = {Frontiers in Microbiology},
  publisher = {FRONTIERS RESEARCH FOUNDATION},
  year = {2011},
  volume = {2},
  pages = {62},
  doi = {10.3389/fmicb.2011.00062}
}
Mansour AS and Sassen R (2011), "Mineralogical and stable isotopic characterization of authigenic carbonate from a hydrocarbon seep site, Gulf of Mexico slope: Possible relation to crude oil degradation", Marine Geology. Vol. 281(1-4), pp. 59-69.
Abstract: One of the characteristic features on the cold deep seafloor on Atwater Valley (AT) Block 425 (1930 m water depth) in the Gulf of Mexico is the occurrence of seepage of crude oil and hydrocarbon gases associated with thermogenic gas hydrate and authigenic carbonate deposits. Mineralogical, petrographic and isotopic analyses revealed that the precipitation of these carbonates was related to the microbial oxidation of hydrocarbons. Carbonate deposits are composed of heavily oil-stained, small nodules to large cobbles of dense limestones of fine-grained textures. Other carbonate fragments are composed of small intraclasts, pellets and some bivalve shell fragments cemented together by aragonite cement. XRD analysis and petrographic investigations revealed that the authigenic carbonate is predominantly composed of aragonite that occurs as microcrystalline matrix and cement. Microcrystalline, sparitic and botryoidal acicular aragonite crystals are observed as void-filling cement. The δ18O values of the authigenic carbonate (3.80 to 4.16‰ V-PDB) suggest that the precipitating fluid has equilibrated with the cold bottom seawater. The calculated δ18O values (0.18 to 0.54‰ SMOW) of the precipitating fluid show subtle deviation from the values reported for the present bottom seawater. This is attributed possibly to the precipitation from pore water with temperature ranged from 3.3 to 1.7 °C, which is less than the measured bottom seawater (4 °C). However, the mixing of the marine pore water with some deep hydrocarbon-rich brines or hydrate-water would provide a source of 18O-enrichment fluid for the precipitation of the authigenic carbonates. Based on the predominance of aragonite with botryoidal and clotted fabric, the occurrence of pyrite and from the oxygen isotopic data, it is plausible that the authigenic carbonates may have formed near the sediment/water interface in an oxygen-depleted environment with low temperature. The narrow range of the δ13C values of the authigenic carbonate (− 23.88 to − 28.62‰ V-PDB) suggests that a single source of carbon is predominant. Based on the moderately low δ13C values and the occurrence of spots of crude oil coatings of the carbonate samples, in addition to the application of a carbon isotope mass balance model, the carbon involving in the formation of the carbonates of the AT 425 seep site could be mainly derived from microbial degradation of crude oil. Microbial oxidation of non-methane thermogenic hydrocarbon gases such as ethane, propane and isobutane would play some role as a source of carbonate-carbon.
BibTeX:
@article{Mansour2011,
  author = {Mansour, A S and Sassen, R},
  title = {Mineralogical and stable isotopic characterization of authigenic carbonate from a hydrocarbon seep site, Gulf of Mexico slope: Possible relation to crude oil degradation},
  journal = {Marine Geology},
  year = {2011},
  volume = {281},
  number = {1-4},
  pages = {59--69},
  url = {http://dx.doi.org/10.1016/j.margeo.2011.02.004},
  doi = {10.1016/j.margeo.2011.02.004}
}
Mottl MJ, Seewald JS, Wheat CG, Tivey MK, Michael PJ, Proskurowski G, McCollom TM, Reeves E, Sharkey J, You CF, Chan LH and Pichler T (2011), "Chemistry of hot springs along the Eastern Lau Spreading Center", Geochimica et Cosmochimica Acta. Vol. 75(4), pp. 1013-1038.
Abstract: The Eastern Lau Spreading Center (ELSC) is the southernmost part of the back-arc spreading axis in the Lau Basin, west of the Tonga trench and the active Tofua volcanic arc. Over its 397-km length it exhibits large and systematic changes in spreading rate, magmatic/tectonic processes, and proximity to the volcanic arc. In 2005, we collected 81 samples of vent water from six hydrothermal fields along the ELSC. The chemistry of these waters varies both within and between vent fields, in response to changes in substrate composition, temperature and pressure, pH, water/rock ratio, and input from magmatic gases and subducted sediment. Hot-spring temperatures range from 229° to 363 °C at the five northernmost fields, with a general decrease to the south that is reversed at the Mariner field. The southernmost field, Vai Lili, emitted water at up to 334 °C in 1989 but had a maximum venting temperature of only 121 °C in 2005, due to waning activity and admixture of bottom seawater into the subseafloor plumbing system. Chloride varies both within fields and from one field to another, from a low of 528 mmol/kg to a high of 656 mmol/kg, and may be enriched by phase separation and/or leaching of Cl from the rock. Concentrations of the soluble elements K, Rb, Cs, and B likewise increase southward as the volcanic substrate becomes more silica-rich, especially on the Valu Fa Ridge. Iodine and δ7Li increase southward, and δ11B decreases as B increases, apparently in response to increased input from subducted sediment as the arc is approached. Species that decrease southward as temperature falls are Si, H2S, Li, Na/Cl, Fe, Mn, and 87Sr/86Sr, whereas pH, alkalinity, Ca, and Sr increase. Oxygen isotopes indicate a higher water/rock ratio in the three systems on Valu Fa Ridge, consistent with higher porosity in more felsic volcanic rocks. Vent waters at the Mariner vent field on the Valu Fa Ridge are significantly hotter, more acid and metal-rich, less saline, and richer in dissolved gases and other volatiles, including H2S, CO2, and F, than the other vent fields, consistent with input of magmatic gases. The large variations in geologic and geophysical parameters produced by back-arc spreading along the ELSC, which exceed those along mid-ocean ridge spreading axes, produce similar large variations in the composition of vent waters, and thus provide new insights into the processes that control the chemistry of submarine hot springs.
BibTeX:
@article{Mottl2011,
  author = {Mottl, M J and Seewald, J S and Wheat, C G and Tivey, M K and Michael, P J and Proskurowski, G and McCollom, T M and Reeves, E and Sharkey, J and You, C F and Chan, L H and Pichler, T},
  title = {Chemistry of hot springs along the Eastern Lau Spreading Center},
  journal = {Geochimica et Cosmochimica Acta},
  year = {2011},
  volume = {75},
  number = {4},
  pages = {1013--1038},
  url = {http://dx.doi.org/10.1016/j.gca.2010.12.008},
  doi = {10.1016/j.gca.2010.12.008}
}
Orcutt BN, Sylvan JB, Knab NJ and Edwards KJ (2011), "Microbial Ecology of the Dark Ocean above, at, and below the Seafloor ", Microbiology and Molecular Biology Reviews. Vol. 75(2), pp. 361-422.
Abstract: The majority of life on Earth—notably, microbial life—occurs in places that do not receive sunlight, with the habitats of the oceans being the largest of these reservoirs. Sunlight penetrates only a few tens to hundreds of meters into the ocean, resulting in large-scale microbial ecosystems that function in the dark. Our knowledge of microbial processes in the dark ocean—the aphotic pelagic ocean, sediments, oceanic crust, hydrothermal vents, etc.—has increased substantially in recent decades. Studies that try to decipher the activity of microorganisms in the dark ocean, where we cannot easily observe them, are yielding paradigm-shifting discoveries that are fundamentally changing our understanding of the role of the dark ocean in the global Earth system and its biogeochemical cycles. New generations of researchers and experimental tools have emerged, in the last decade in particular, owing to dedicated research programs to explore the dark ocean biosphere. This review focuses on our current understanding of microbiology in the dark ocean, outlining salient features of various habitats and discussing known and still unexplored types of microbial metabolism and their consequences in global biogeochemical cycling. We also focus on patterns of microbial diversity in the dark ocean and on processes and communities that are characteristic of the different habitats.
BibTeX:
@article{Orcutt2011,
  author = {Orcutt, B N and Sylvan, J B and Knab, N J and Edwards, K J},
  title = {Microbial Ecology of the Dark Ocean above, at, and below the Seafloor },
  journal = {Microbiology and Molecular Biology Reviews},
  year = {2011},
  volume = {75},
  number = {2},
  pages = {361--422},
  url = {http://dx.doi.org/10.1128/​MMBR.00039-10},
  doi = {10.1128/MMBR.00039-10}
}
Pester NJ, Rough M, Ding K and Seyfried WE (2011), "A new Fe/Mn geothermometer for hydrothermal systems: Implications for high-salinity fluids at 13°N on the East Pacific Rise", Geochimica et Cosmochimica Acta. Vol. 75(24), pp. 7881-7892.
Abstract: Field and experimental investigations demonstrate the chemistry of mid-ocean ridge hydrothermal vent fluids reflects fluid–mineral reaction at higher temperatures than those typically measured at the seafloor. To account for this and, in turn, be able to better constrain sub-seafloor hydrothermal processes, we have developed an empirical geothermometer based on the dissolved Fe/Mn ratio in high-temperature fluids. Using data from basalt alteration experiments, the relationship; T (°C) = 331.24 + 112.41*log[Fe/Mn] has been calibrated between 350 and 450 °C. The apparent Fe–Mn equilibrium demonstrated by the experimental data is in good agreement with natural vent fluids, suggesting broad applicability. When used in conjunction with constraints imposed by quartz solubility, associated sub-seafloor pressures can be estimated for basalt-hosted systems. As an example, this methodology is used to interpret new data from 13°N on the East Pacific Rise, where high-temperature fluids both enriched and depleted in chloride (339–646 mmol/kg), relative to seawater, are actively venting within a close proximity. Accounting for these variable salinities, active phase separation is clearly taking place at 13°N, yet the fluid Fe/Mn ratios and the silica concentrations suggest equilibration at temperatures less than those coinciding with the two-phase region. These data show the chloride-enriched fluid reflects the highest temperature and pressure (∼432 °C, 400 bars) of equilibration, consistent with circulation near the top of the inferred magma chamber. This is in agreement with the elevated CO2 concentration relative to the chloride-depleted fluids. The noted temperature derived from the Fe/Mn geothermometer is higher than the critical temperature for a fluid of equivalent salinity. This carries the important implication that, despite being chloride-enriched relative to seawater, these fluids evolved as the vapor component of even higher salinity brine.
BibTeX:
@article{Pester2011,
  author = {Pester, N J and Rough, M and Ding, K and Seyfried, W E},
  title = {A new Fe/Mn geothermometer for hydrothermal systems: Implications for high-salinity fluids at 13°N on the East Pacific Rise},
  journal = {Geochimica et Cosmochimica Acta},
  year = {2011},
  volume = {75},
  number = {24},
  pages = {7881--7892},
  url = {http://dx.doi.org/10.1016/j.gca.2011.08.043},
  doi = {10.1016/j.gca.2011.08.043}
}
Pietruszka AJ, Keyes MJ, Duncan JA, Hauri EH, Carlson RW and Garcia MO (2011), "Excesses of seawater-derived 234U in volcanic glasses from Loihi Seamount due to crustal contamination", Earth and Planetary Science Letters. Vol. 304(1-2), pp. 280-289.
Abstract: The effects of crustal contamination on the chemistry of oceanic basalts are commonly assumed to be negligible due to the compositional similarity between the erupted basalt and the underlying oceanic crust or volcanic edifice. Here we evaluate this assumption with high-precision measurements of the 234U–238U and 230Th–238U disequilibria, Cl/K2O ratios, and 87Sr/86Sr ratios of volcanic glasses from Loihi Seamount, a submarine Hawaiian volcano with an active hydrothermal system. The samples, including one from the volcano's 1996 eruption, have small to moderate amounts of excess 234U (˜ 0.2–1.0%) and variable, elevated Cl/K2O ratios. These excesses of 234U and enrichments in Cl are thought to result from contamination with seawater-derived U and Cl, but neither of these signatures can be explained by syn- or post-eruptive interaction between lava and seawater. Instead, mantle-derived magmas at Loihi appear to be variably contaminated with two distinct crustal materials: hydrothermal brines (which create enrichments in Cl) and U-enriched hydrothermally altered rocks (which create excesses of 234U). Both of these materials are expected to be found within the volcanic edifice as complementary parts of the volcano's hydrothermal system. The Loihi glasses display a wide measured range in the amount of excess 230Th from ˜1 to 7% (due to the addition of seawater-derived U) that overlaps with lavas from Kilauea Volcano (˜ 2% excess 230Th). We correct the 230Th–238U disequilibria of the Loihi glasses back to their original pre-contamination values using their 234U–238U disequilibria and a simple mass-balance calculation. This correction suggests that mantle-derived magmas at Loihi have a narrow range of ˜ 6–9% excess 230Th, which is significantly larger than observed for lavas from the neighboring volcano, Kilauea. This difference is consistent with the idea that Loihi is tapping mantle that is upwelling slowly (˜ 5–6 cm/yr) on the margin of the Hawaiian plume.
BibTeX:
@article{Pietruszka2011,
  author = {Pietruszka, A J and Keyes, M J and Duncan, J A and Hauri, E H and Carlson, R W and Garcia, M O},
  title = {Excesses of seawater-derived 234U in volcanic glasses from Loihi Seamount due to crustal contamination},
  journal = {Earth and Planetary Science Letters},
  year = {2011},
  volume = {304},
  number = {1-2},
  pages = {280--289},
  url = {http://dx.doi.org/10.1016/j.epsl.2011.02.018},
  doi = {10.1016/j.epsl.2011.02.018}
}
Quistad SD and Valentine DL (2011), "Anaerobic propane oxidation in marine hydrocarbon seep sediments", Geochimica et Cosmochimica Acta. Vol. 75(8), pp. 2159-2169.
Abstract: Propane (C3H8) is an abundant hydrocarbon in subsurface reservoirs with significance to atmospheric chemistry and to marine biogeochemistry. The anaerobic oxidation of propane coupled to sulfate reduction may prevent sub-seafloor accumulations of propane from entering the ocean and atmosphere. Anaerobic oxidation of propane has recently been demonstrated in cultures of novel sulfate-reducing bacteria, but has not been directly demonstrated or quantified in nature. In this work we describe a method involving incubation with 13C-propane to quantify rates of anaerobic oxidation of propane in anoxic sediment, and we conclusively demonstrate the oxidation of propane under sulfidic conditions in fresh sediments of a marine hydrocarbon seep. Observed rates of anaerobic oxidation of propane adhere to first-order kinetic behavior, enabling the modification of this method for whole core rate determinations. Whole core rates in nine cores from two hydrocarbon seeps measured 0.04–2100 nmoles C3H8 cm−3 day−1 by this method. The seep persistently supplied with more propane displayed substantially higher rates of anaerobic oxidation of propane, by 1–2 orders of magnitude when averaged over the top 10-cm, suggesting the development of the microbial community is strongly modulated by the availability of propane. This work is the first to estimate rates for anaerobic oxidation of propane in any environment, and demonstrates the potential importance of the process as a filter for preventing propane from entering the ocean and atmosphere.
BibTeX:
@article{Quistad2011,
  author = {Quistad, S D and Valentine, D L},
  title = {Anaerobic propane oxidation in marine hydrocarbon seep sediments},
  journal = {Geochimica et Cosmochimica Acta},
  year = {2011},
  volume = {75},
  number = {8},
  pages = {2159--2169},
  url = {http://dx.doi.org/10.1016/j.gca.2011.02.001},
  doi = {10.1016/j.gca.2011.02.001}
}
Reeves E, Seewald JS, Saccocia PJ, Walsh E, Bach W, Craddock PR, Shanks WC, Sylva SP, Pichler T and Rosner M (2011), "Geochemistry of hydrothermal fluids from the PACMANUS, Northeast Pual and Vienna Woods hydrothermal fields, Manus Basin, Papua New Guinea", Geochimica et Cosmochimica Acta. Vol. 75(4), pp. 1088-1123.
Abstract: Processes controlling the composition of seafloor hydrothermal fluids in silicic back-arc or near-arc crustal settings remain poorly constrained despite growing evidence for extensive magmatic–hydrothermal activity in such environments. We conducted a survey of vent fluid compositions from two contrasting sites in the Manus back-arc basin, Papua New Guinea, to examine the influence of variations in host rock composition and magmatic inputs (both a function of arc proximity) on hydrothermal fluid chemistry. Fluid samples were collected from felsic-hosted hydrothermal vent fields located on Pual Ridge (PACMANUS and Northeast (NE) Pual) near the active New Britain Arc and a basalt-hosted vent field (Vienna Woods) located farther from the arc on the Manus Spreading Center. Vienna Woods fluids were characterized by relatively uniform endmember temperatures (273–285 °C) and major element compositions, low dissolved CO2 concentrations (4.4 mmol/kg) and high measured pH (4.2–4.9 at 25 °C). Temperatures and compositions were highly variable at PACMANUS/NE Pual and a large, newly discovered vent area (Fenway) was observed to be vigorously venting boiling (358 °C) fluid. All PACMANUS fluids are characterized by negative δDH2OδDH2O values, in contrast to positive values at Vienna Woods, suggesting substantial magmatic water input to circulating fluids at Pual Ridge. Low measured pH (25 °C) values (∼2.6–2.7), high endmember CO2 (up to 274 mmol/kg) and negative δ34SH2Sδ34SH2S values (down to −2.7‰) in some vent fluids are also consistent with degassing of acid-volatile species from evolved magma. Dissolved CO2 at PACMANUS is more enriched in 13C (−4.1‰ to −2.3‰) than Vienna Woods (−5.2‰ to −5.7‰), suggesting a contribution of slab-derived carbon. The mobile elements (e.g. Li, K, Rb, Cs and B) are also greatly enriched in PACMANUS fluids reflecting increased abundances in the crust there relative to the Manus Spreading Center. Variations in alkali and dissolved gas abundances with Cl at PACMANUS and NE Pual suggest that phase separation has affected fluid chemistry despite the low temperatures of many vents. In further contrast to Vienna Woods, substantial modification of PACMANUS/NE Pual fluids has taken place as a result of seawater ingress into the upflow zone. Consistently high measured Mg concentrations as well as trends of increasingly non-conservative SO4 behavior, decreasing endmember Ca/Cl and Sr/Cl ratios with increased Mg indicate extensive subsurface anhydrite deposition is occurring as a result of subsurface seawater entrainment. Decreased pH and endmember Fe/Mn ratios in higher Mg fluids indicate that the associated mixing/cooling gives rise to sulfide deposition and secondary acidity production. Several low temperature (⩽80 °C) fluids at PACMANUS/NE Pual also show evidence for anhydrite dissolution and water–rock interaction (fixation of B) subsequent to seawater entrainment. Hence, the evolution of fluid compositions at Pual Ridge reflects the cumulative effects of water/rock interaction, admixing and reaction of fluids exsolved from silicic magma, phase separation/segregation and seawater ingress into upflow zones.
BibTeX:
@article{Reeves2011,
  author = {Reeves, E and Seewald, J S and Saccocia, P J and Walsh, E and Bach, W and Craddock, P R and Shanks, W C and Sylva, S P and Pichler, T and Rosner, M},
  title = {Geochemistry of hydrothermal fluids from the PACMANUS, Northeast Pual and Vienna Woods hydrothermal fields, Manus Basin, Papua New Guinea},
  journal = {Geochimica et Cosmochimica Acta},
  year = {2011},
  volume = {75},
  number = {4},
  pages = {1088--1123},
  url = {http://dx.doi.org/10.1016/j.gca.2010.11.008},
  doi = {10.1016/j.gca.2010.11.008}
}
Schmidt K, Garbe-Schonberg D, Koschinsky A, Strauss H, Jost CL, Klevenz V and Koniger P (2011), "Fluid elemental and stable isotope composition of the Nibelungen hydrothermal field (8 degrees18'S, Mid-Atlantic Ridge): Constraints on fluid-rock interaction in heterogeneous lithosphere", Chemical Geology. Vol. 280(1-2), pp. 1-18.
Abstract: Depending on the geological setting, the interaction of submarine hydrothermal fluids with the host rock leads to distinct energy and mass transfers between the lithosphere and the hydrosphere. The Nibelungen hydrothermal field is located at 8°18′S, about 9 km off-axis of the Mid-Atlantic Ridge (MAR). At 3000 m water depth, 372 °C hot, acidic fluids emanate directly from the bottom, without visible sulfide chimney formation. Hydrothermal fluids obtained in 2009 are characterized by low H2S concentrations (1.1 mM), a depletion of B (192 μM) relative to seawater, lower Si (13.7 mM) and Li (391 μM) concentrations relative to basaltic-hosted hydrothermal systems and a large positive Eu anomaly, and display a distinct stable isotope signature of hydrogen (∆2HH2O = 7.6–8.7‰) and of oxygen (∆18OH2O = 2.2–2.4‰). The heavy hydrogen isotopic signature of the Nibelungen fluids is a specific feature of ultramafic-hosted hydrothermal systems and is mainly controlled by the formation of OH-bearing alteration minerals like serpentine, brucite, and tremolite during pervasive serpentinization. New isotopic data obtained for the ultramafic-hosted Logatchev I field at 14°45′N, MAR (∆2HH2O = 3.8–4.2‰) display a similar trend, being clearly distinguished from other, mafic-hosted hydrothermal systems at the MAR. The fluid geochemistry at Nibelungen kept stable since the first sampling campaign in 2006 and is evident for a hybrid alteration of mafic and ultramafic rocks in the subseafloor. Whereas the ultramafic-fingerprint parameters Si, Li, B, Eu anomaly and ∆2HH2O distinguish the Nibelungen field from other hydrothermal systems venting in basaltic settings at similar physico-chemical conditions and are related to the interaction with mantle rocks, the relatively high concentrations of trace alkali elements, Pb, and Tl can only be attributed to the alteration of melt-derived gabbroic rocks. The elemental and isotopic composition of the fluid suggest a multi-step alteration sequence: (1) low- to medium-temperature alteration of gabbroic rocks, (2) pervasive serpentinization at moderate to high temperatures, and (3) limited high-temperature interaction with basaltic rocks during final ascent of the fluid. The integrated water/rock ratio for the Nibelungen hydrothermal system is about 0.5. The fluid compositional fingerprint at Nibelungen is similar to the ultramafic-hosted Logatchev I fluids with respect to key parameters. Some compositional differences can be ascribed to different alteration temperatures and other fluid pathways involving a variety of source rocks, higher water/rock ratios, and sulfide precipitation in the sub-seafloor at Logatchev I.
BibTeX:
@article{Schmidt2011,
  author = {Schmidt, K and Garbe-Schonberg, D and Koschinsky, A and Strauss, H and Jost, C L and Klevenz, V and Koniger, P},
  title = {Fluid elemental and stable isotope composition of the Nibelungen hydrothermal field (8 degrees18'S, Mid-Atlantic Ridge): Constraints on fluid-rock interaction in heterogeneous lithosphere},
  journal = {Chemical Geology},
  year = {2011},
  volume = {280},
  number = {1-2},
  pages = {1--18},
  url = {http://dx.doi.org/10.1016/j.chemgeo.2010.07.008},
  doi = {10.1016/j.chemgeo.2010.07.008}
}
Seyfried WE, Pester NJ, Ding K and Rough M (2011), "Vent fluid chemistry of the Rainbow Hydrothermal System (36 degrees N, MAR): Phase equilibria and in-situ pH controls on subseafloor alteration processes", Geochimica et Cosmochimica Acta. Vol. 75(6), pp. 1574-1593.
Abstract: The Rainbow hydrothermal field is located at 36°13.8′N–33°54.15′W at 2300 m depth on the western flank of a non-volcanic ridge between the South AMAR and AMAR segments of the Mid-Atlantic Ridge. The hydrothermal field consists of 10–15 active chimneys that emit high-temperature (∼365 °C) fluid. In July 2008, vent fluids were sampled during cruise KNOX18RR, providing a rich dataset that extends in time information on subseafloor chemical and physical processes controlling vent fluid chemistry at Rainbow. Data suggest that the Mg concentration of the hydrothermal end-member is not zero, but rather 1.5–2 mmol/kg. This surprising result may be caused by a combination of factors including moderately low dissolved silica, low pH, and elevated chloride of the hydrothermal fluid. Combining end-member Mg data with analogous data for dissolved Fe, Si, Al, Ca, and H2, permits calculation of mineral saturation states for minerals thought appropriate for ultramafic-hosted hydrothermal systems at temperatures and pressures in keeping with constraints imposed by field observations. These data indicate that chlorite solid solution, talc, and magnetite achieve saturation in Rainbow vent fluid at a similar pH(T,P) (400 °C, 500 bar) of approximately 4.95, while higher pH values are indicated for serpentine, suggesting that serpentine may not coexist with the former assemblage at depth at Rainbow. The high Fe/Mg ratio of the Rainbow vent fluid notwithstanding, the mole fraction of clinochlore and chamosite components of chlorite solid solution at depth are predicted to be 0.78 and 0.22, respectively. In situ pH measurements made at Rainbow vents are in good agreement with pH(T,P) values estimated from mineral solubility calculations, when the in situ pH data are adjusted for temperature and pressure. Calculations further indicate that pH(T,P) and dissolved H2 are extremely sensitive to changes in dissolved silica owing to constraints imposed by chlorite solid solution-fluid equilibria. Indeed, the predicted correlation between dissolved silica and H2 defines a trend that is in good agreement with vent fluid data from Rainbow and other high-temperature ultramafic-hosted hydrothermal systems. We speculate that the moderate concentrations of dissolved silica in vent fluids from these systems result from hydrothermal alteration of plagioclase and olivine in the form of subsurface gabbroic intrusions, which, in turn are variably replaced by chlorite + magnetite + talc ± tremolite, with important implications for pH lowering, dissolved sulfide concentrations, and metal mobility.
BibTeX:
@article{Seyfried2011,
  author = {Seyfried, W E and Pester, N J and Ding, K and Rough, M},
  title = {Vent fluid chemistry of the Rainbow Hydrothermal System (36 degrees N, MAR): Phase equilibria and in-situ pH controls on subseafloor alteration processes},
  journal = {Geochimica et Cosmochimica Acta},
  year = {2011},
  volume = {75},
  number = {6},
  pages = {1574--1593},
  url = {http://dx.doi.org/10.1016/j.gca.2011.01.001},
  doi = {10.1016/j.gca.2011.01.001}
}
Smith A, Popa R, Fisk M, Nielsen M, Wheat CG, Jannasch HW, Fisher AT, Becker K, Sievert SM and Flores G (2011), "In situ enrichment of ocean crust microbes on igneous minerals and glasses using an osmotic flow-through device", Geochemistry, Geophysics, Geosystems. Vol. 12, pp. Q06007.
Abstract: The Integrated Ocean Drilling Program (IODP) Hole 1301A on the eastern flank of Juan de Fuca Ridge was used in the first long-term deployment of microbial enrichment flow cells using osmotically driven pumps in a subseafloor borehole. Three novel osmotically driven colonization systems with unidirectional flow were deployed in the borehole and incubated for 4 years to determine the microbial colonization preferences for 12 minerals and glasses present in igneous rocks. Following recovery of the colonization systems, we measured cell density on the minerals and glasses by fluorescent staining and direct counting and found some significant differences between mineral samples. We also determined the abundance of mesophilic and thermophilic culturable organotrophs grown on marine R2A medium and identified isolates by partial 16S or 18S rDNA sequencing. We found that nine distinct phylotypes of culturable mesophilic oligotrophs were present on the minerals and glasses and that eight of the nine can reduce nitrate and oxidize iron. Fe(II)-rich olivine minerals had the highest density of total countable cells and culturable organotrophic mesophiles, as well as the only culturable organotrophic thermophiles. These results suggest that olivine (a common igneous mineral) in seawater-recharged ocean crust is capable of supporting microbial communities, that iron oxidation and nitrate reduction may be important physiological characteristics of ocean crust microbes, and that heterogeneously distributed minerals in marine igneous rocks likely influence the distribution of microbial communities in the ocean crust.
BibTeX:
@article{Smith2011,
  author = {Smith, A and Popa, R and Fisk, M and Nielsen, M and Wheat, C G and Jannasch, H W and Fisher, A T and Becker, K and Sievert, S M and Flores, G},
  title = {In situ enrichment of ocean crust microbes on igneous minerals and glasses using an osmotic flow-through device},
  journal = {Geochemistry, Geophysics, Geosystems},
  year = {2011},
  volume = {12},
  pages = {Q06007},
  url = {http://dx.doi.org/10.1029/2010GC003424},
  doi = {10.1029/2010GC003424}
}
Wanless VD, Perfit MR, Ridley WI, Wallace PJ, Grimes CB and Klein EM (2011), "Volatile abundances and oxygen isotopes in basaltic to dacitic lavas on mid-ocean ridges: The role of assimilation at spreading centers", Chemical Geology. Vol. 287(1-2), pp. 54-65.
Abstract: Most geochemical variability in MOR basalts is consistent with low- to moderate-pressure fractional crystallization of various mantle-derived parental melts. However, our geochemical data from MOR high-silica glasses, including new volatile and oxygen isotope data, suggest that assimilation of altered crustal material plays a significant role in the petrogenesis of dacites and may be important in the formation of basaltic lavas at MOR in general. MOR high-silica andesites and dacites from diverse areas show remarkably similar major element trends, incompatible trace element enrichments, and isotopic signatures suggesting similar processes control their chemistry. In particular, very high Cl and elevated H2O concentrations and relatively light oxygen isotope ratios (˜ 5.8‰ vs. expected values of ˜ 6.8‰) in fresh dacite glasses can be explained by contamination of magmas from a component of ocean crust altered by hydrothermal fluids. Crystallization of silicate phases and Fe-oxides causes an increase in δ18O in residual magma, but assimilation of material initially altered at high temperatures results in lower δ18O values. The observed geochemical signatures can be explained by extreme fractional crystallization of a MOR basalt parent combined with partial melting and assimilation (AFC) of amphibole-bearing altered oceanic crust. The MOR dacitic lavas do not appear to be simply the extrusive equivalent of oceanic plagiogranites. The combination of partial melting and assimilation produces a distinct geochemical signature that includes higher incompatible trace element abundances and distinct trace element ratios relative to those observed in plagiogranites.
BibTeX:
@article{Wanless2011,
  author = {Wanless, V D and Perfit, M R and Ridley, W I and Wallace, P J and Grimes, C B and Klein, E M},
  title = {Volatile abundances and oxygen isotopes in basaltic to dacitic lavas on mid-ocean ridges: The role of assimilation at spreading centers},
  journal = {Chemical Geology},
  year = {2011},
  volume = {287},
  number = {1-2},
  pages = {54--65},
  url = {http://dx.doi.org/10.1016/j.chemgeo.2011.05.017},
  doi = {10.1016/j.chemgeo.2011.05.017}
}
Yucel M, Gartman A, Chan CS and Luther GW (2011), "Hydrothermal vents as a kinetically stable source of iron-sulphide-bearing nanoparticles to the ocean", Nature Geoscience. NEW YORK; 75 VARICK ST, 9TH FLR, NEW YORK, NY 10013-1917 USA, jun, 2011. Vol. 4(6), pp. 367-371. NATURE PUBLISHING GROUP.
Abstract: Hydrothermal vents emit sulphur and metals to the ocean(1). Particular attention has been paid to hydrothermal fluxes of iron(2-4), a limiting micronutrient of marine primary production(5). Vent-derived iron was previously thought to rapidly oxidize and precipitate around vents(6). However, organic matter can bind to and stabilize dissolved and particulate iron in hydrothermal plumes(7-9), facilitating its dispersion into the open ocean(10). Here, we report measurements of the chemical speciation of sulphide and iron in high-temperature fluids emanating from vents in the East Pacific Rise and the Eastern Lau Spreading Center. We show that pyrite nanoparticles-composed of iron and sulphur-account for up to 10% of the filterable iron (less than 200nm in size) in these fluids. We suggest that these particles form before the discharge of the vent fluid. We estimate that pyrite nanoparticles sink more slowly than larger plume particles, and are more resistant to oxidation than dissolved Fe(II) and FeS. We suggest that the discharge of iron in the form of pyrite nanoparticles increases the probability that vent-derived iron will be transported over long distances in the deep ocean.
BibTeX:
@article{Yucel2011,
  author = {Yucel, M and Gartman, A and Chan, Clara S and Luther, G W},
  title = {Hydrothermal vents as a kinetically stable source of iron-sulphide-bearing nanoparticles to the ocean},
  journal = {Nature Geoscience},
  publisher = {NATURE PUBLISHING GROUP},
  year = {2011},
  volume = {4},
  number = {6},
  pages = {367--371},
  doi = {10.1038/NGEO1148}
}
Bailey JV, Raub TD, Meckler AN, Harrison BK, Raub TMD, Green AM and Orphan VJ (2010), "Pseudofossils in relict methane seep carbonates resemble endemic microbial consortia", Palaeogeography, Palaeoclimatology, Palaeoecology. Vol. 285(1-2), pp. 131-142.
Abstract: Pleistocene-age methane seep carbonates from the Eel River Basin, California contain aggregate-like structures composed of tightly-packed hollow spheres that morphologically resemble syntrophic archaeal–bacterial consortia known to catalyze the anaerobic oxidation of methane (AOM). Tetragonal microstructures also present in the carbonates resemble seep-endemic Methanosarcinales cell clusters. Despite morphological similarities to the seep-endemic microbes that likely mediated the authigenesis of Eel River Basin carbonates and sulfides, detailed petrographic, SEM, and magnetic microscopic imaging, remanence rock magnetism, laser Raman, and energy dispersive X-ray spectroscopy, suggest that these microstructures are not microfossils, but rather mineral structures that result from the diagenetic alteration of euhedral Fe-sulfide framboids. Electron microscopy shows that during diagenesis, reaction rims composed of Fe oxide form around framboid microcrystalites. Subsequent dissolution of greigite or pyrite crystals leaves behind hollow cell-like casings (external molds) — a transformation that occurs on timescales of ∼100 kyr or less. Despite their superficial resemblance to morphologically-distinctive extant microbes in local sediments, the presence of acellular precursor grains, as well as of partially-altered transitional forms, complicate the interpretation of these and other framboidal microstructures that have been reported from the rock record.
BibTeX:
@article{Bailey2010,
  author = {Bailey, J V and Raub, T D and Meckler, A N and Harrison, B K and Raub, T M D and Green, A M and Orphan, V J},
  title = {Pseudofossils in relict methane seep carbonates resemble endemic microbial consortia},
  journal = {Palaeogeography, Palaeoclimatology, Palaeoecology},
  year = {2010},
  volume = {285},
  number = {1-2},
  pages = {131--142},
  url = {http://dx.doi.org/10.1016/j.palaeo.2009.11.002},
  doi = {10.1016/j.palaeo.2009.11.002}
}
Baker MC, Ramirez-Llodra E, Tyler PA, German CR, Boetius A, Cordes EE, Dubilier N, Fisher CR, Levin LA, Metaxas A, Rowden R, Santos RS, Shank R, Van Dover CL, Young C and Waren A (2010), "Biogeography, Ecology and Vulnerability of Chemosynthetic Ecosystems in the Deep Sea", In Life in the World's Oceans: Diversity, Distribution, and Abundance. , pp. 161-182. Wiley-Blackwell.
BibTeX:
@incollection{Baker2010,
  author = {Baker, M C and Ramirez-Llodra, E and Tyler, P A and German, C R and Boetius, A and Cordes, E E and Dubilier, N and Fisher, C R and Levin, L A and Metaxas, A and Rowden, R and Santos, R S and Shank, R and Van Dover, C L and Young, C and Waren, A},
  title = {Biogeography, Ecology and Vulnerability of Chemosynthetic Ecosystems in the Deep Sea},
  booktitle = {Life in the World's Oceans: Diversity, Distribution, and Abundance},
  publisher = {Wiley-Blackwell},
  year = {2010},
  pages = {161--182}
}
Barker AK, Coogan LA and Gillis KM (2010), "Insights into the behaviour of sulphur in mid-ocean ridge axial hydrothermal systems from the composition of the sheeted dyke complex at Pito Deep", Chemical Geology. Vol. 275(1-2), pp. 105-115.
Abstract: The behaviour of seawater sulphate in hydrothermal systems at intermediate- to fast-spreading ridges is investigated using new analyses of the δ34S, sulphur concentration and Fe2O3/Fe2O3total, combined with existing 87Sr/86Sr, of sheeted dykes from the Pito Deep tectonic window. The Pito Deep sheeted dyke complex has a similar composition to the sheeted dykes drilled at ODP Hole 504B suggesting that the measured compositions are representative of sheeted dyke complexes at intermediate- to fast-spreading ridges. The dykes show only small increases in δ34S which, combined with the rock dominated δ34S of vent fluids, requires the majority of seawater sulphate to be precipitated as anhydrite before the fluid reacts with the sheeted dyke complex. This loss of sulphate from the fluid means that a much higher Fe2O3 in the sheeted dyke complex than in fresh MORB glasses cannot be explained by oxidation due to seawater sulphate reduction during fluid–rock reaction. Instead, oxidation probably occurs due to degassing of reduced species, largely H2, during dyke emplacement and solidification. A mass balance model that accounts for anhydrite precipitation and Sr partitioning into the anhydrite, as well as fitting the concentration and isotopic ratios of S and Sr in the sheeted dykes and vent fluids, suggests water/rock ratios of ∼ 1. For a 1 km thick sheeted dyke complex this is equivalent to a fluid flux of ∼ 3 × 106 kg m− 2, sufficient to remove ∼ 60% of the latent heat of crystallization from the lower crust.
BibTeX:
@article{Barker2010,
  author = {Barker, A K and Coogan, L A and Gillis, K M},
  title = {Insights into the behaviour of sulphur in mid-ocean ridge axial hydrothermal systems from the composition of the sheeted dyke complex at Pito Deep},
  journal = {Chemical Geology},
  year = {2010},
  volume = {275},
  number = {1-2},
  pages = {105--115},
  url = {http://dx.doi.org/10.1016/j.chemgeo.2010.05.003},
  doi = {10.1016/j.chemgeo.2010.05.003}
}
Becker EL, Lee RW, Macko SA, Faure BM and Fisher CR (2010), "Stable carbon and nitrogen isotope compositions of hydrocarbon-seep bivalves on the Gulf of Mexico lower continental slope", Deep-Sea Research. Part II: Topical Studies in Oceanography. Vol. 57(21-23), pp. 1957-1964.
Abstract: Stable isotope compositions of cold-seep bivalves can illuminate processes that affect the chemical and isotopic compositions of seeping fluids along the continental slope of the Gulf of Mexico as well as provide insight into the physiological ecology of these species. Carbon and nitrogen isotope compositions were analyzed in mussels and clams from 14 seep sites spanning a depth range of 1000 to 2800 m along the lower Louisiana slope of the Gulf of Mexico. Mussels of three species found on the lower slope, Bathymodiolus childressi, B. brooksi, and B. heckerae, showed site-specific differences in tissue δ13C, reflecting differences in the local methane pool. Mussels from sites on the lower slope sitting atop the contiguous salt sheet generally had tissue δ13C values that reflected a stronger biogenic methane signal (−70.8 to −58.8‰) than mussels on the upper slope or seaward of the Sigsbee Escarpment (−67.3 to −40.4‰). Clams (Calyptogena ponderosa and Calyptogena sp. nov.) had a narrow range of δ13C values between −37.0 and −34.4‰, indicating that their thiotrophic symbionts are fixing primarily seawater-dissolved organic carbon. The most depleted tissue δ15N values yet published for both mussels and clams are reported in this study at −23.7 and −9.2‰, respectively. These depleted values have implications for the assimilation of inorganic nitrogen by these symbioses and the concentrations of particular inorganic nitrogen sources in the local environment.
BibTeX:
@article{Becker2010,
  author = {Becker, E L and Lee, R W and Macko, S A and Faure, B M and Fisher, C R},
  title = {Stable carbon and nitrogen isotope compositions of hydrocarbon-seep bivalves on the Gulf of Mexico lower continental slope},
  journal = {Deep-Sea Research. Part II: Topical Studies in Oceanography},
  year = {2010},
  volume = {57},
  number = {21-23},
  pages = {1957--1964},
  url = {http://dx.doi.org/10.1016/j.dsr2.2010.05.002},
  doi = {10.1016/j.dsr2.2010.05.002}
}
Bernardino AF and Smith CR (2010), "Community structure of infaunal macrobenthos around vestimentiferan thickets at the San Clemente cold seep, NE Pacific", Marine Ecology. Vol. 31(4), pp. 608-621.
Abstract: The San Clemente cold seep lies within 100–200 km of other reducing habitats in the NE Pacific, offering an opportunity to compare diversity and species overlap among reducing habitats (i.e. whale-, kelp-, and wood-falls) at similar depths within a single region. Video observations from the research submersible Alvin at the San Clemente seep (1800 m depth) indicated clumps (‘thickets') of vestimentiferans distributed as meter-scale patches interspersed with vesicomyid clam beds and black sediments. Sediment-core samples were collected at distances of 0 to 80–200 m along randomly oriented transects radiating outward from vestimentiferan thickets to evaluate changes in macrofaunal community structure from thickets into the background community. Macrofaunal abundance was elevated at distances of 0–1 m compared to 80–200 m (i.e. the ‘background' community). The tube-building frenulate worms Siboglinum spp., along with peracarid crustaceans, dominated sediments within 1 m of vestimentiferan thickets. Species diversity was depressed within 1 m of thickets but with high rates of species accumulation, suggesting that seep sites greatly increase sediment heterogeneity and facilitate colonization by non-background macrofaunal species. Stable isotope data indicate chemosynthetic nutrition for some dominant macrofaunal species within 1 m of tubeworm thickets. The macrofaunal community near vestimentiferan thickets in San Clemente seep contains intermediate levels of species richness and diversity compared to other deep-sea seep areas in the northeast Pacific. There was low species overlap between the San Clemente seep macrofauna and communities in reducing habitats near wood-, whale-, and kelp-falls at similar depths within the region, suggesting that seeps harbor a distinct infaunal community.
BibTeX:
@article{Bernardino2010,
  author = {Bernardino, A F and Smith, C R},
  title = {Community structure of infaunal macrobenthos around vestimentiferan thickets at the San Clemente cold seep, NE Pacific},
  journal = {Marine Ecology},
  year = {2010},
  volume = {31},
  number = {4},
  pages = {608--621},
  url = {http://dx.doi.org/10.1111/j.1439-0485.2010.00389.x},
  doi = {10.1111/j.1439-0485.2010.00389.x}
}
Bernhard JM, Martin JB and Rathburn AE (2010), "Combined carbonate carbon isotopic and cellular ultrastructural studies of individual benthic foraminifera : 2. Toward an understanding of apparent disequilibrium in hydrocarbon seeps", Paleoceanography. Vol. 25, pp. PA4206.
Abstract: Numerous previous studies show disequilibrium between stable carbon isotope ratios of foraminiferal calcite and pore water dissolved inorganic carbon in hydrocarbon seeps, calling into question the utility of this widely used paleoceanographic tracer as a proxy. We use a recently developed method to compare stable carbon isotope ratios of foraminiferal carbonate with cell ultrastructural observations from individual benthic foraminifera from seep (under chemosynthetic bivalves) and nonseep habitats in Monterey Bay, California, to better understand control(s) of benthic foraminiferal carbon isotope ratios. Two attributes previously proposed to cause the isotopic offsets are diet and symbionts. Ultrastructural analysis shows that positive staining with Rose Bengal indicates presence of foraminiferal cytoplasm, bacterial biomass, or a combination of both and, thus, is not an unequivocal indicator of viability. We also show for the first time that some living seep foraminifera have endobionts. Results from our unique, yet limited, data set are consistent with suggestions that, in our sites, several foraminiferal species collected from seep clam beds may not survive there, diet and symbiont presence do not appear to be major contributors to disequilibrium, little calcification of seep-tolerant foraminiferal species occurs while seep conditions prevail, and microscale variability in habitats could influence δ13C of benthic foraminiferal carbonate. Results further suggest that our knowledge of benthic foraminiferal ecology and biomineralization, especially in extreme habitats such as seeps, must be bolstered before we fully understand the fidelity of paleoenvironmental records derived from benthic foraminiferal test δ13C data.
BibTeX:
@article{Bernhard2010,
  author = {Bernhard, J M and Martin, J B and Rathburn, A E},
  title = {Combined carbonate carbon isotopic and cellular ultrastructural studies of individual benthic foraminifera : 2. Toward an understanding of apparent disequilibrium in hydrocarbon seeps},
  journal = {Paleoceanography},
  year = {2010},
  volume = {25},
  pages = {PA4206},
  url = {http://dx.doi.org/10.1029/2010PA001930},
  doi = {10.1029/2010PA001930}
}
Brazelton WJ, Sogin ML and Baross JA (2010), "Multiple scales of diversification within natural populations of archaea in hydrothermal chimney biofilms", Environmental Microbiology Reports. Vol. 2(2), pp. 236-242.
Abstract: Corroborative data collected from 16S rRNA clone libraries, intergenic transcribed spacer (ITS) region clone libraries, and 16S rRNA hypervariable region tag pyrosequencing demonstrate microdiversity within single-species archaeal biofilms of the Lost City Hydrothermal Field. Both 16S rRNA clone libraries and pyrosequencing of the V6 hypervariable region show that Lost City Methanosarcinales (LCMS) biofilms are dominated by a single sequence, but the pyrosequencing data set also reveals the presence of an additional 1654 rare sequences. Clone libraries constructed with DNA spanning the V6 hypervariable region and ITS show that multiple ITS sequences are associated with the same dominant V6 sequence. Furthermore, ITS variability differed among three chimney samples, and the sample with the highest ITS diversity also contained the highest V6 diversity as measured by clone libraries as well as tag pyrosequencing. These results indicate that the extensive microdiversity detected in V6 tag sequences is an underestimate of genetic diversity within the archaeal biofilms.
BibTeX:
@article{Brazelton2010,
  author = {Brazelton, W J and Sogin, M L and Baross, J A},
  title = {Multiple scales of diversification within natural populations of archaea in hydrothermal chimney biofilms},
  journal = {Environmental Microbiology Reports},
  year = {2010},
  volume = {2},
  number = {2},
  pages = {236--242},
  url = {http://dx.doi.org/10.1111/j.1758-2229.2009.00097.x},
  doi = {10.1111/j.1758-2229.2009.00097.x}
}
Brazelton WJ, Ludwig KA, Sogin ML, Andreishcheva EN, Kelley DS, Shen CC, Edwards RL and Baross JA (2010), "Archaea and bacteria with surprising microdiversity show shifts in dominance over 1,000-year time scales in hydrothermal chimneys", Proceedings of the National Academy of Sciences of the United States of America. Vol. 107(4), pp. 1612-1617.
Abstract: The Lost City Hydrothermal Field, an ultramafic-hosted system located 15 km west of the Mid-Atlantic Ridge, has experienced at least 30,000 years of hydrothermal activity. Previous studies have shown that its carbonate chimneys form by mixing of ∼90 °C, pH 9–11 hydrothermal fluids and cold seawater. Flow of methane and hydrogen-rich hydrothermal fluids in the porous interior chimney walls supports archaeal biofilm communities dominated by a single phylotype of Methanosarcinales. In this study, we have extensively sampled the carbonate-hosted archaeal and bacterial communities by obtaining sequences of textgreater200,000 amplicons of the 16S rRNA V6 region and correlated the results with isotopic (230Th) ages of the chimneys over a 1,200-year period. Rare sequences in young chimneys were commonly more abundant in older chimneys, indicating that members of the rare biosphere can become dominant members of the ecosystem when environmental conditions change. These results suggest that a long history of selection over many cycles of chimney growth has resulted in numerous closely related species at Lost City, each of which is preadapted to a particular set of reoccurring environmental conditions. Because of the unique characteristics of the Lost City Hydrothermal Field, these data offer an unprecedented opportunity to study the dynamics of a microbial ecosystem's rare biosphere over a thousand-year time scale.
BibTeX:
@article{Brazelton2010a,
  author = {Brazelton, W J and Ludwig, K A and Sogin, M L and Andreishcheva, E N and Kelley, D S and Shen, C C and Edwards, R L and Baross, J A},
  title = {Archaea and bacteria with surprising microdiversity show shifts in dominance over 1,000-year time scales in hydrothermal chimneys},
  journal = {Proceedings of the National Academy of Sciences of the United States of America},
  year = {2010},
  volume = {107},
  number = {4},
  pages = {1612--1617},
  url = {http://dx.doi.org/10.1073/pnas.0905369107},
  doi = {10.1073/pnas.0905369107}
}
Bright M, Plum C, Riavitz LA, Arbizu PM, Cordes EE and Gollner S (2010), "Epizooic metazoan meiobenthos associated with tubeworm and mussel aggregations from cold seeps of the northern Gulf of Mexico", Deep-Sea Research. Part II: Topical Studies in Oceanography. Vol. 57(21-23), pp. 1982-1989.
Abstract: The abundance and higher taxonomic composition of epizooic metazoan meiobenthic communities associated with mussel and tubeworm aggregations of hydrocarbon seeps at Green Canyon, Atwater Valley, and Alaminos Canyon in depths between 1400 and 2800 m were studied and compared to the infaunal community of non-seep sediments nearby. Epizooic meiofaunal abundances of associated meiobenthos living in tubeworm bushes and mussel beds at seeps were extremely low (usually textless100 ind. 10 cm−2), similar to epizooic meiofauna at deep-sea hydrothermal vents, and the communities were composed primarily of nematodes, copepods, ostracods, and halacarids. In contrast, epizooic meiobenthic abundance is lower than previous studies have reported for infauna from seep sediments. Interestingly, non-seep sediments contained higher abundances and higher taxonomic diversity than epizooic seep communities, although in situ primary production is restricted to seeps.
BibTeX:
@article{Bright2010,
  author = {Bright, M and Plum, C and Riavitz, L A and Arbizu, P M and Cordes, E E and Gollner, S},
  title = {Epizooic metazoan meiobenthos associated with tubeworm and mussel aggregations from cold seeps of the northern Gulf of Mexico},
  journal = {Deep-Sea Research. Part II: Topical Studies in Oceanography},
  year = {2010},
  volume = {57},
  number = {21-23},
  pages = {1982--1989},
  url = {http://dx.doi.org/10.1016/j.dsr2.2010.05.003},
  doi = {10.1016/j.dsr2.2010.05.003}
}
Carney RS (2010), "Stable isotope trophic patterns in echinoderm megafauna in close proximity to and remote from Gulf of Mexico lower slope hydrocarbon seeps", Deep-Sea Research. Part II: Topical Studies in Oceanography. Vol. 57(21-23), pp. 1965-1971.
Abstract: Hydrocarbon-seep communities in the Gulf of Mexico have a high biomass that is exploited as a food source to varying degrees by the photosynthesis-dependent fauna inhabiting the surrounding mud bottom. A decline concurrent with ocean depth in detritus influx to that background habitat results in a much lower background biomass. The biomass contrast between population-rich seeps and depauperate mud bottom leads to the prediction that seep utilization by the background fauna should be extensive at all depths and should increase with depth. Species depth zonation makes like-species comparisons over the full depth of the Gulf of Mexico impossible. Seeps and normal bottom above 1000 m have different fauna from those below 1000 m. Lower slope seeps are surrounded by a fauna rich in echinoderm species, especially asteroids, ophiuroids, and holothuroids. All three taxa have species that are abundant within seeps and are probably endemic to them. They also contain species found only in mud background or within mud and seeps backgrounds. Tissue analyses of δ13C and δ15N of echinoderms collected by ROV within seeps and trawling away from seeps indicate a pattern of utilization similar to that found in upper slope seeps exploited by different taxa. Seastar and ophiuroid species abundant in or endemic to seeps have tissue isotope values reflecting seep chemosynthetic input via a free-living microbial detritus or predation. A single seep-endemic deposit-feeding holothuroid showed distinct seep tissue values. Background deposit-feeding holothuroids collected within seeps showed either no or only minor incorporation of seep carbon, indicating either a lack of access to seep detritus or short feeding times within the seep. A predicted extensive utilization of seep productivity at the deeper seeps was not found. Seeps may be relatively closed systems that require special adaptations of species in order for them to enter, exploit, and survive. Alternately, the surrounding deep benthos may not be as food-poor as assumed from biomass measurements and flux estimates.
BibTeX:
@article{Carney2010,
  author = {Carney, R S},
  title = {Stable isotope trophic patterns in echinoderm megafauna in close proximity to and remote from Gulf of Mexico lower slope hydrocarbon seeps},
  journal = {Deep-Sea Research. Part II: Topical Studies in Oceanography},
  year = {2010},
  volume = {57},
  number = {21-23},
  pages = {1965--1971},
  url = {http://dx.doi.org/10.1016/j.dsr2.2010.09.027},
  doi = {10.1016/j.dsr2.2010.09.027}
}
Chadwick WW, Embley RW, Baker ET, Resing JA, Lupton JE, Cashman KV, Dziak RP, Tunnicliffe V, Butterfield DA and Tamura Y (2010), "Northwest Rota-1 Seamount", Oceanography., mar, 2010. Vol. 23(1), pp. 182-183.
Abstract: Northwest Rota-1 Seamount is the first place on Earth where a submarine volcanic eruption was witnessed in 2004, and, remarkably, it appears that the volcano has been erupting continuously ever since. NW Rota-1 is located ˜ 100 km north of Guam in the western Pacific, within the newly designated Mariana Trench Marine National Monument (http://www.fws.gov/marianastrenchmarinemonument). With a summit depth of 520 m, it is a symmetrical cone of basaltic andesite composition (Figure 1) formed in the subduction zone setting of the Mariana volcanic arc. It was identified as a site of particular interest in 2003 when sampling of its overlying hydrothermal plume showed very high magmatic volatile input (Resing et al., 2007). Consequently, it was one of several seamounts targeted for dives with a remotely operated vehicle the following year. During these dives, an actively erupting vent was discovered at a depth of 550 m; lava, fluid, and gas samples were collected; and colonies of shrimp, limpets, and crabs (some of them new species) were found living in the volcano summit's harsh conditions (Embley et al., 2006; Limén et al., 2006).
BibTeX:
@article{Chadwick2010,
  author = {Chadwick, W W and Embley, R W and Baker, E T and Resing, J A and Lupton, J E and Cashman, K V and Dziak, R P and Tunnicliffe, V and Butterfield, D A and Tamura, Y},
  title = {Northwest Rota-1 Seamount},
  journal = {Oceanography},
  year = {2010},
  volume = {23},
  number = {1},
  pages = {182--183},
  doi = {10.5670/oceanog.2010.82}
}
Chadwick WW, Butterfield DA, Embley RW, Tunnicliffe V, Huber JA, Nooner SL and Clague DA (2010), "Axial Seamount", Oceanography., mar, 2010. Vol. 23(1), pp. 38-39.
Abstract: Axial Seamount is a hotspot volcano superimposed on the Juan de Fuca Ridge (JdFR) in the Northeast Pacific Ocean. Due to its robust magma supply, it rises ˜ 800 m above the rest of JdFR and has a large elongate summit caldera with two rift zones that parallel and overlap with adjacent segments of the spreading center (Figure 1). Submersible dives at Axial in 1983–1984 discovered the first active black smoker vents in the Northeast Pacific (Chase et al., 1985). The New Millennium Observatory (NeMO; http://www.pmel.noaa.gov/vents/nemo) was established at Axial in 1996 to study volcanic events and the perturbations they cause to hydrothermal and biological systems. As if on cue, Axial erupted in January 1998 and was the first seafloor eruption detected remotely and monitored by in situ instruments (Embley et al., 1999). In fact, one instrument caught in a 1998 lava flow was later recovered with data intact, providing new insight into the emplacement of submarine lavas (Chadwick, 2003). Initially, research focused on mapping, sampling, and documenting the impact of the eruption on the hydrothermal vents and biological communities (Figure 2). The emphasis has gradually shifted to long-term geophysical, geochemical, and biological monitoring of the volcano in anticipation of its next eruption.
BibTeX:
@article{Chadwick2010a,
  author = {Chadwick, W W and Butterfield, D A and Embley, R W and Tunnicliffe, V and Huber, J A and Nooner, S L and Clague, D A},
  title = {Axial Seamount},
  journal = {Oceanography},
  year = {2010},
  volume = {23},
  number = {1},
  pages = {38--39},
  doi = {10.5670/oceanog.2010.73}
}
Cho WW and Shank TM (2010), "Incongruent patterns of genetic connectivity among four ophiuroid species with differing coral host specificity on North Atlantic seamounts", Marine Ecology. Vol. 31(S1), pp. 121-143.
Abstract: Seamounts are considered to play a defining role in the evolution and diversity of marine fauna, acting as ‘stepping-stones' for dispersal, regional centers of genetic isolation and speciation, and refugia for deep-sea populations. This study focused on the patterns of dispersal and genetic connectivity of four seamount ophiuroid species (Asteroschema clavigera, Ophiocreas oedipus, Ophioplinthaca abyssalis, and Ophioplinthaca chelys) displaying differing levels of associative (epifaunal) specificity to cold-water coral hosts inhabiting the New England and Corner Rise Seamount chains, and Muir Seamount in the Northwestern Atlantic. Analyses of mt16S and mtCOI revealed evidence for recent population expansion and high gene flow for all four species. However, species-specific genetic differentiation was significant based on seamount region and depth. Significant differences were found among regional seamount groups for A. clavigera, within seamount regions and seamounts for O. chelys, among 250-m depth intervals for A. clavigera, among 100-m depth intervals for O. oedipus, and there were indications of isolation by distance for A. clavigera and O. oedipus. In addition, A. clavigera and O. oedipus, broadcast spawners with high fidelity to specific coral hosts, displayed predominantly westward historical migration, whereas the ophioplinthacids, with lower host-specificity, displayed predominantly eastward migration. No congruent patterns of historical migration were evident among species and seamounts, yet these patterns can be correlated with species-specific host specificity, specific depth strata, and dispersal strategies. Conservation efforts to protect seamount ecosystems should promote multi-species approaches to genetic connectivity, and consider the impact of the ‘dependence' of biodiversity on host fauna in these vulnerable marine ecosystems.
BibTeX:
@article{Cho2010,
  author = {Cho, W W and Shank, T M},
  title = {Incongruent patterns of genetic connectivity among four ophiuroid species with differing coral host specificity on North Atlantic seamounts},
  journal = {Marine Ecology},
  year = {2010},
  volume = {31},
  number = {S1},
  pages = {121--143},
  url = {http://dx.doi.org/10.1111/j.1439-0485.2010.00395.x},
  doi = {10.1111/j.1439-0485.2010.00395.x}
}
Cordes EE, Becker EL, Hourdez S and Fisher CR (2010), "Influence of foundation species, depth, and location on diversity and community composition at Gulf of Mexico lower-slope cold seeps", Deep-Sea Research. Part II: Topical Studies in Oceanography. Vol. 57(21-23), pp. 1870-1881.
Abstract: Efforts to understand and preserve the seep communities of the deep Gulf of Mexico (GOM) begin with a comprehensive survey of the biodiversity of these communities. Previous studies have provided a conceptual model of the physiology, population, and community ecology of upper continental slope seeps. However, seeps at water depths below 1000 m in the Gulf of Mexico remain relatively unknown. In this study, data from 47 samples of tubeworm- and mussel-associated communities at depths of 1005–2750 m are examined. Other than tubeworms and mussels, 66 taxa of macro- and megafauna were collected, 43 of which appear to be restricted to water depths of over 1000 m, and 39 that have not been reported previously from the Gulf of Mexico. Diversity in mussel beds was highest at mid-slope depths, but tubeworm-associated communities did not show clear bathymetric trends in diversity. Diversity was higher in tubeworm aggregations at the alpha level (per sample), but higher in mussel beds at the beta level (species turnover among collections). Although both community types were often numerically dominated by the endemic shrimp Alvinocaris muricola, broad differences in the communities hosted by tubeworm aggregations and mussel beds were apparent. The most important factors explaining community similarity within community type were the depth, relative abundance of different mussel species in a bed, and the average size of tubeworms in an aggregation. The high proportion of deep-seep species that were found for the first time in the Gulf of Mexico emphasizes the importance of conservation efforts for these patchy communities.
BibTeX:
@article{Cordes2010,
  author = {Cordes, E E and Becker, E L and Hourdez, S and Fisher, C R},
  title = {Influence of foundation species, depth, and location on diversity and community composition at Gulf of Mexico lower-slope cold seeps},
  journal = {Deep-Sea Research. Part II: Topical Studies in Oceanography},
  year = {2010},
  volume = {57},
  number = {21-23},
  pages = {1870--1881},
  url = {http://dx.doi.org/10.1016/j.dsr2.2010.05.010},
  doi = {10.1016/j.dsr2.2010.05.010}
}
Craddock PR, Bach W, Seewald JS, Rouxel OJ, Reeves E and Tivey MK (2010), "Rare earth element abundances in hydrothermal fluids from the Manus Basin, Papua New Guinea: indicators of sub-seafloor hydrothermal processes in back-arc basins", Geochimica et Cosmochimica Acta. Vol. 74(19), pp. 5494-5513.
Abstract: Rare earth element (REE) concentrations are reported for a large suite of seafloor vent fluids from four hydrothermal systems in the Manus back-arc basin (Vienna Woods, PACMANUS, DESMOS and SuSu Knolls vent areas). Sampled vent fluids show a wide range of absolute REE concentrations and chondrite-normalized (REEN) distribution patterns (LaN /SmN ∼ 0.6–11; LaN /YbN ∼ 0.6 – 71; View the MathML sourceEuN/EuN∗∼1–55). REEN distribution patterns in different vent fluids range from light-REE enriched, to mid- and heavy-REE enriched, to flat, and have a range of positive Eu-anomalies. This heterogeneity contrasts markedly with relatively uniform REEN distribution patterns of mid-ocean ridge hydrothermal fluids. In Manus Basin fluids, aqueous REE compositions do not inherit directly or show a clear relationship with the REE compositions of primary crustal rocks with which hydrothermal fluids interact. These results suggest that the REEs are less sensitive indicators of primary crustal rock composition despite crustal rocks being the dominant source of REEs in submarine hydrothermal fluids. In contrast, differences in aqueous REE compositions are consistently correlated with differences in fluid pH and ligand (chloride, fluoride and sulfate) concentrations. Our results suggest that the REEs can be used as an indicator of the type of magmatic acid volatile (i.e., presence of HF, SO2) degassing in submarine hydrothermal systems. Additional fluid data suggest that near-seafloor mixing between high-temperature hydrothermal fluid and locally entrained seawater at many vent areas in the Manus Basin causes anhydrite precipitation. Anhydrite effectively incorporates REE and likely affects measured fluid REE concentrations, but does not affect their relative distributions.
BibTeX:
@article{Craddock2010,
  author = {Craddock, P R and Bach, W and Seewald, J S and Rouxel, O J and Reeves, E and Tivey, M K},
  title = {Rare earth element abundances in hydrothermal fluids from the Manus Basin, Papua New Guinea: indicators of sub-seafloor hydrothermal processes in back-arc basins},
  journal = {Geochimica et Cosmochimica Acta},
  year = {2010},
  volume = {74},
  number = {19},
  pages = {5494--5513},
  url = {http://dx.doi.org/10.1016/j.gca.2010.07.003},
  doi = {10.1016/j.gca.2010.07.003}
}
Craddock PR and Bach W (2010), "Insights to magmatic–hydrothermal processes in the Manus back–arc Basin as recorded by anhydrite", Geochimica et Cosmochimica Acta. Vol. 74(19), pp. 5514-5536.
Abstract: Microchemical analyses of rare earth element (REE) concentrations and Sr and S isotope ratios of anhydrite are used to identify sub-seafloor processes governing the formation of hydrothermal fluids in the convergent margin Manus Basin, Papua New Guinea. Samples comprise drill-core vein anhydrite and seafloor massive anhydrite from the PACMANUS (Roman Ruins, Snowcap and Fenway) and SuSu Knolls (North Su) active hydrothermal fields. Chondrite-normalized REE patterns in anhydrite show remarkable heterogeneity on the scale of individual grains, different from the near uniform REEN patterns measured in anhydrite from mid-ocean ridge deposits. The REEN patterns in anhydrite are correlated with REE distributions measured in hydrothermal fluids venting at the seafloor at these vent fields and are interpreted to record episodes of hydrothermal fluid formation affected by magmatic volatile degassing. 87Sr/86Sr ratios vary dramatically within individual grains between that of contemporary seawater and that of endmember hydrothermal fluid. Anhydrite was precipitated from a highly variable mixture of the two. The intra-grain heterogeneity implies that anhydrite preserves periods of contrasting hydrothermal versus seawater dominant near-seafloor fluid circulation. Most sulfate δ34S values of anhydrite cluster around that of contemporary seawater, consistent with anhydrite precipitating from hydrothermal fluid mixed with locally entrained seawater. Sulfate δ34S isotope ratios in some anhydrites are, however, lighter than that of seawater, which are interpreted as recording a source of sulfate derived from magmatic SO2 degassed from underlying felsic magmas in the Manus Basin. The range of elemental and isotopic signatures observed in anhydrite records a range of sub-seafloor processes including high-temperature hydrothermal fluid circulation, varying extents of magmatic volatile degassing, seawater entrainment and fluid mixing. The chemical and isotopic heterogeneity recorded in anhydrite at the inter- and intra-grain scale captures the dynamics of hydrothermal fluid formation and sub-seafloor circulation that is highly variable both spatially and temporally on timescales over which hydrothermal deposits are formed. Microchemical analysis of hydrothermal minerals can provide information about the temporal history of submarine hydrothermal systems that are variable over time and cannot necessarily be inferred only from the study of vent fluids.
BibTeX:
@article{Craddock2010a,
  author = {Craddock, P R and Bach, W},
  title = {Insights to magmatic–hydrothermal processes in the Manus back–arc Basin as recorded by anhydrite},
  journal = {Geochimica et Cosmochimica Acta},
  year = {2010},
  volume = {74},
  number = {19},
  pages = {5514--5536},
  url = {http://dx.doi.org/10.1016/j.gca.2010.07.004},
  doi = {10.1016/j.gca.2010.07.004}
}
Cruse AM and Seewald JS (2010), "Low-molecular weight hydrocarbons in vent fluids from the Main Endeavour Field, northern Juan de Fuca Ridge", Geochimica et Cosmochimica Acta. Vol. 74(21), pp. 6126-6140.
Abstract: Despite its location on sediment-free basalt, vent fluids from the Main Endeavour Field (MEF) contain chemical species that indicate fluids have interacted with sediments during circulation. We report on the distribution and isotopic abundances of organic compounds (C1–C3 alkanes and alkenes, benzene and toluene) in fluids collected from the Main Endeavour Field (MEF) in July, 2000, to understand the processes that regulate their abundances and characterize fluid sources. Aqueous organic compounds are derived from the thermal alteration of sedimentary organic matter and subsequently undergo further oxidation reactions during fluid flow. Fluid:sediment mass ratios calculated using ΣNH4 concentrations indicate that the sediments are distal to the MEF, resulting in a common reservoir of fluids for all of the vents. Following the generation from sediment alteration, aqueous organic compounds undergo secondary alteration reactions via a stepwise oxidation reaction mechanism. Alkane distributions and isotopic compositions indicate that organic compounds in MEF fluids have undergone a greater extent of alteration as compared to Middle Valley fluids, either due to differences in subsurface redox conditions or the residence time of fluids at subsurface conditions. The distributions of the aromatic compounds benzene and toluene are qualitatively consistent with the subsurface conditions indicated by equilibration of aqueous alkanes and alkanes. However, benzene and toluene do not achieve chemical equilibrium in the subsurface. Methane and CO2 also do not equilibrate chemically or isotopically at reaction zone temperatures, a likely result of an insufficient reaction time after addition of CO2 from magmatic sources during upflow. The organic geochemistry supports the assumption that the sediments with which MEF fluids interact has the same composition as sediments present in Middle Valley itself, and highlight differences in subsurface reaction zone conditions and fluid flow pathways at these two sites.
BibTeX:
@article{Cruse2010,
  author = {Cruse, A M and Seewald, J S},
  title = {Low-molecular weight hydrocarbons in vent fluids from the Main Endeavour Field, northern Juan de Fuca Ridge},
  journal = {Geochimica et Cosmochimica Acta},
  year = {2010},
  volume = {74},
  number = {21},
  pages = {6126--6140},
  url = {http://dx.doi.org/10.1016/j.gca.2010.07.013},
  doi = {10.1016/j.gca.2010.07.013}
}
Dick HJB, Lissenberg CJ and Warren JM (2010), "Mantle melting, melt transport, and delivery beneath a slow-spreading ridge: the paleo-MAR from 23 degrees15′N to 23 degrees 45′N", Journal of Petrology. Vol. 51(1-2), pp. 425-467.
Abstract: Kane Megamullion, an oceanic core complex near the Mid-Atlantic Ridge (MAR) abutting the Kane Transform, exposes nearly the full plutonic foundation of the MARK paleo-ridge segment. This provides the first opportunity for a detailed look at the patterns of mantle melting, melt transport and delivery at a slow-spreading ridge. The Kane lower crust and mantle section is heterogeneous, as a result of focused mantle melt flow to different points beneath the ridge segment in time and space, over an ∼300–400 kyr time scale. The association of residual mantle peridotite, dunite and troctolite with a large ∼1 km+ thick gabbro section at the Adam Dome Magmatic Center in the southern third of the complex probably represents the crust–mantle transition. This provides direct evidence for local melt accumulation in the shallow mantle near the base of the crust as a result of dilation accompanying corner flow beneath the ridge. Dunite and troctolite with high-Mg Cpx represent melt–rock reaction with the mantle, and suggest that this should be taken into account in modeling the evolution of mid-ocean ridge basalt (MORB). Despite early precipitation of high-Mg Cpx, wehrlites similar to those in many ophiolites were not found. Peridotite modes from the main core complex and transform wall define a depletion trend coincident with that for the SW Indian Ridge projecting toward East Pacific Rise mantle exposed at Hess Deep. The average Kane transform peridotite is a lherzolite with 5textperiodcentered2% Cpx, whereas that from the main core complex is a harzburgite with only 3textperiodcentered5% Cpx. As the area corresponds to a regional bathymetric low, and the crust is apparently thin, it is likely that most residual mantle along the MAR is significantly more depleted. Thus, harzburgitic and lherzolitic ophiolite subtypes cannot be simply interpreted as slow- and fast-spreading ridges respectively. The mantle peridotites are consistent with a transform edge effect caused by juxtaposition of old cold lithosphere against upwelling mantle at the ridge–transform intersection. This effect is far more local, confined to within 10 km of the transform slip zone, and far smaller than previously thought, corresponding to ∼8% as opposed to 12textperiodcentered5% melting of a pyrolitic mantle away from the transform. Excluding the transform, the overall degree of melting over 3 Myr indicated by the peridotites is uniform, ranging from ∼11textperiodcentered3 to 13textperiodcentered8%. Large variations in composition for a single dredge or ROV dive, however, reflect local melt transport through the shallow mantle. This produced variable extents of melt–rock reaction, dunite formation, and melt impregnation. At least three styles of late mantle metasomatism are present. Small amounts of plagioclase with elevated sodium and titanium and alumina-depletion in pyroxene relative to residual spinel peridotites represent impregnation by a MORB-like melt. Highly variable alumina depletion in pyroxene rims in spinel peridotite probably represents cryptic metasomatism by small volumes of late transient silica-rich melts meandering through the shallow mantle. Direct evidence for such melts is seen in orthopyroxenite veins. Finally, a late hydrous fluid may be required to explain anomalous pyroxene sodium enrichment in spinel peridotites. The discontinuous thin lower crust exposed at Kane Megamullion contrasts with the textgreater700 km2 1textperiodcentered5 km+ thick Atlantis Bank gabbro massif at the SW Indian Ridge (SWIR), clearly showing more robust magmatism at the latter. However, the SWIR spreading rate is 54% of the MAR rate, the offset of the Atlantis II Fracture Zone is 46% greater and Na8 of the spatially associated basalts 16% greater—all of which predict precisely the opposite. At the same time, the average compositions of Kane and Atlantis II transform peridotites are nearly identical. This is best explained by a more fertile parent mantle beneath the SWIR and demonstrates that crustal thickness predicted by simply inverting MORB compositions can be significantly in error.
BibTeX:
@article{Dick2010,
  author = {Dick, H J B and Lissenberg, C J and Warren, J M},
  title = {Mantle melting, melt transport, and delivery beneath a slow-spreading ridge: the paleo-MAR from 23 degrees15′N to 23 degrees 45′N},
  journal = {Journal of Petrology},
  year = {2010},
  volume = {51},
  number = {1-2},
  pages = {425--467},
  url = {http://dx.doi.org/10.1093/petrology/egp088},
  doi = {10.1093/petrology/egp088}
}
Feng D and Roberts HH (2010), "Initial results of comparing cold-seep carbonates from mussel- and tubeworm-associated environments at Atwater Valley 340, northern Gulf of Mexico", Deep-Sea Research. Part II: Topical Studies in Oceanography. Vol. 57(21-23), pp. 2030-2039.
Abstract: Chemosymbiotic macrofauna (such as mussels and tubeworms) and authigenic carbonates are typical of many hydrocarbon seeps. To address whether mussels and tubeworms could impact the sediment geochemistry of their habitat where authigenic carbonates are precipitated, a comparative study of petrographic and geochemical features of the authigenic carbonates from mussel- and tubeworm-associated environments at hydrocarbon seeps in Atwater Valley lease area block 340 (AT340) of the Gulf of Mexico was undertaken. Both mussel- and tubeworm-associated carbonates are dominated by high-magnesium calcite (HMC) and aragonite, and two tubeworm-associated carbonate samples have minor amounts of dolomite. The δ13C values of all carbonates are low, ranging from −60.8‰ to −35.5‰ PDB. Although there is much overlap, surprisingly the δ13C values of mussel-associated carbonates are generally higher than those of tubeworm-associated carbonates (−51.8‰ vs. −54.8‰ for an average of over 60 subsamples). It is suggested that (1) carbon isotopic vital effect of seep mussels and tubeworms, (2) fluid physical pumping of mussels, and (3) release of sulfate by tubeworm roots may be responsible for the relatively lower δ13C values of tubeworm-associated carbonates. It has been suggested that the heterogeneities in mineralogy and stable carbon isotope geochemistry of the seep carbonates may be attributed to the activity of macrofauna (mussels and tubeworms) and associated microbes. Our observations also suggest that at AT340 the geochemical evolution of seep macrofauna is from a mussel-dominated environment to a mixed mussel-tubeworm environment, and finally to a mostly tubeworm-dominated environment. This evolution is controlled mainly by the habitat, e.g., hydrocarbon seep flux.
BibTeX:
@article{Feng2010,
  author = {Feng, D and Roberts, H H},
  title = {Initial results of comparing cold-seep carbonates from mussel- and tubeworm-associated environments at Atwater Valley 340, northern Gulf of Mexico},
  journal = {Deep-Sea Research. Part II: Topical Studies in Oceanography},
  year = {2010},
  volume = {57},
  number = {21-23},
  pages = {2030--2039},
  url = {http://dx.doi.org/10.1016/j.dsr2.2010.05.004},
  doi = {10.1016/j.dsr2.2010.05.004}
}
Ferri G, Jakuba MV and Yoerger DR (2010), "A novel trigger-based method for hydrothermal vents prospecting using an autonomous underwater robot", Autonomous Robots. Vol. 29(1), pp. 67-83.
Abstract: In this paper we address the problem of localizing active hydrothermal vents on the seafloor using an Autonomous Underwater Vehicle (AUV). The plumes emitted by hydrothermal vents are the result of thermal and chemical inputs from submarine hot spring systems into the overlying ocean. The Woods Hole Oceanographic Institution's Autonomous Benthic Explorer (ABE) AUV has successfully localized previously undiscovered hydrothermal vent fields in several recent vent prospecting expeditions. These expeditions utilized the AUV for a three-stage, nested survey strategy approach (German et al. in Deep Sea Res. I 55:203–219, 2008). Each stage consists of a survey flown at successively deeper depths through easier to detect but spatially more constrained vent fluids. Ideally this sequence of surveys culminates in photographic evidence of the vent fields themselves. In this work we introduce a new adaptive strategy for an AUV's movement during the first, highest-altitude survey: the AUV initially moves along pre-designed tracklines but certain conditions can trigger an adaptive movement that is likely to acquire additional high value data for vent localization. The trigger threshold is changed during the mission, adapting the method to the different survey profiles the robot may find. The proposed algorithm is vetted on data from previous ABE missions and measures of efficiency presented.
BibTeX:
@article{Ferri2010,
  author = {Ferri, G and Jakuba, M V and Yoerger, D R},
  title = {A novel trigger-based method for hydrothermal vents prospecting using an autonomous underwater robot},
  journal = {Autonomous Robots},
  year = {2010},
  volume = {29},
  number = {1},
  pages = {67--83},
  url = {http://dx.doi.org/10.1007/s10514-010-9187-y},
  doi = {10.1007/s10514-010-9187-y}
}
Fueri E, Hilton DR, Tryon MD, Brown KM, McMurtry GM, Brueckmann W and Wheat CG (2010), "Carbon release from submarine seeps at the Costa Rica fore arc: Implications for the volatile cycle at the Central America convergent margin", Geochemistry, Geophysics, Geosystems. Vol. 11, pp. Q04S21.
Abstract: We report total dissolved inorganic carbon (DIC) abundances and isotope ratios, as well as helium isotope ratios (3He/4He), of cold seep fluids sampled at the Costa Rica fore arc in order to evaluate the extent of carbon loss from the submarine segment of the Central America convergent margin. Seep fluids were collected over a 12 month period at Mound 11, Mound 12, and Jaco Scar using copper tubing attached to submarine flux meters operating in continuous pumping mode. The fluids show minimum 3He/4He ratios of 1.3 RA (where RA is air 3He/4He), consistent with a small but discernable contribution of mantle-derived helium. At Mound 11, δ13C∑CO2 values between −23.9‰ and −11.6‰ indicate that DIC is predominantly derived from deep methanogenesis and is carried to the surface by fluids derived from sediments of the subducting slab. In contrast, at Mound 12, most of the ascending dissolved methane is oxidized due to lower flow rates, giving extremely low δ13C∑CO2 values ranging from −68.2‰ to −60.3‰. We estimate that the carbon flux (CO2 plus methane) through submarine fluid venting at the outer fore arc is 8.0 × 105 g C km−1 yr−1, which is virtually negligible compared to the total sedimentary carbon input to the margin and the output at the volcanic front. Unless there is a significant but hitherto unidentified carbon flux at the inner fore arc, the implication is that most of the carbon being subducted in Costa Rica must be transferred to the (deeper) mantle, i.e., beyond the depth of arc magma generation.
BibTeX:
@article{Fueri2010,
  author = {Fueri, E and Hilton, D R and Tryon, M D and Brown, K M and McMurtry, G M and Brueckmann, W and Wheat, C G},
  title = {Carbon release from submarine seeps at the Costa Rica fore arc: Implications for the volatile cycle at the Central America convergent margin},
  journal = {Geochemistry, Geophysics, Geosystems},
  year = {2010},
  volume = {11},
  pages = {Q04S21},
  url = {http://dx.doi.org/10.1029/2009GC002810},
  doi = {10.1029/2009GC002810}
}
Garcia-Pineda O, MacDonald IR, Zimmer B, Shedd B and Roberts H (2010), "Remote-sensing evaluation of geophysical anomaly sites in the outer continental slope, northern Gulf of Mexico", Deep-Sea Research. Part II: Topical Studies in Oceanography. Vol. 57(21-23), pp. 1859-1869.
Abstract: Synthetic Aperture Radar (SAR) images obtained from satellites are a reliable tool for localizing natural hydrocarbon seeps. For this study, we used the Texture Classifier Neural Network Algorithm (TCNNA) to interpret SAR data from the RADARSAT satellite and a geostatistical clustering analysis to compare seeps detected in 579 SAR images covering the northern Gulf of Mexico (GOM). Geostatistical analysis results indicate that, in a typical active seep formation, oil vents would be found within a seep formation ∼2.5 km in diameter. Repeated observations of slicks at a given seep formation indicate that advection of rising oil in the water column causes an offset from the vent depending on water depth. At 500 m, the radial offset is up to 1400 m; at 2000 m, it is up to 3270 m. Observations with submersibles showed that, in 100% of the cases, the calculated seep formations that are matched with active oil seeps correspond to anomalies interpreted from surface amplitude maps and migration pathways in the seismic data. However, episodically, larger releases from persistent seeps occurred, and also some other seep formations showed intermittent releases. Our analysis indicates that active oil seeps detected with SAR represent a subset of the total array of geophysical features generated by hydrocarbon migration on the northern continental slope of the Gulf of Mexico.
BibTeX:
@article{Garcia-Pineda2010,
  author = {Garcia-Pineda, O and MacDonald, I R and Zimmer, B and Shedd, B and Roberts, H},
  title = {Remote-sensing evaluation of geophysical anomaly sites in the outer continental slope, northern Gulf of Mexico},
  journal = {Deep-Sea Research. Part II: Topical Studies in Oceanography},
  year = {2010},
  volume = {57},
  number = {21-23},
  pages = {1859--1869},
  url = {http://dx.doi.org/10.1016/j.dsr2.2010.05.005},
  doi = {10.1016/j.dsr2.2010.05.005}
}
German CR, Bowen A, Coleman ML, Honig DL, Huber JA, Jakuba MV, Kinsey JC, Kurz MD, Leroy S, McDermott JM, de Lepinay BM, Nakamura K, Seewald JS, Smith JL, Sylva SP, Van Dover CL, Whitcomb LL and Yoerger DR (2010), "Diverse styles of submarine venting on the ultraslow spreading Mid-Cayman Rise", Proceedings of the National Academy of Sciences of the United States of America., aug, 2010. Vol. 107(32), pp. 14020-14025.
Abstract: Thirty years after the first discovery of high-temperature submarine venting, the vast majority of the global mid-ocean ridge remains unexplored for hydrothermal activity. Of particular interest are the world's ultraslow spreading ridges that were the last to be demonstrated to host high-temperature venting but may host systems particularly relevant to prebiotic chemistry and the origins of life. Here we report evidence for previously unknown, diverse, and very deep hydrothermal vents along the similar to 110 km long, ultraslow spreading Mid-Cayman Rise (MCR). Our data indicate that the MCR hosts at least three discrete hydrothermal sites, each representing a different type of water-rock interaction, including both mafic and ultramafic systems and, at similar to 5,000 m, the deepest known hydrothermal vent. Although submarine hydrothermal circulation, in which seawater percolates through and reacts with host lithologies, occurs on all mid-ocean ridges, the diversity of vent types identified here and their relative geographic isolation make the MCR unique in the oceans. These new sites offer prospects for an expanded range of vent-fluid compositions, varieties of abiotic organic chemical synthesis and extremophile microorganisms, and unparalleled faunal biodiversity-all in close proximity.
BibTeX:
@article{German2010,
  author = {German, C R and Bowen, A and Coleman, M L and Honig, D L and Huber, J A and Jakuba, M V and Kinsey, J C and Kurz, M D and Leroy, S and McDermott, J M and de Lepinay, B M and Nakamura, K and Seewald, J S and Smith, J L and Sylva, S P and Van Dover, C L and Whitcomb, L L and Yoerger, D R},
  title = {Diverse styles of submarine venting on the ultraslow spreading Mid-Cayman Rise},
  journal = {Proceedings of the National Academy of Sciences of the United States of America},
  year = {2010},
  volume = {107},
  number = {32},
  pages = {14020--14025},
  doi = {10.1073/pnas.1009205107}
}
Goss AR, Perfit MR, Ridley WI, Rubin KH, Kamenov GD, Soule SA, Fundis A and Fornari DJ (2010), "Geochemistry of lavas from the 2005-2006 eruption at the East Pacific Rise, 9 degrees 46'N-9 degrees 56'N: Implications for ridge crest plumbing and decadal changes in magma chamber compositions", Geochemistry, Geophysics, Geosystems. Vol. 11, pp. Q05T09.
Abstract: Detailed mapping, sampling, and geochemical analyses of lava flows erupted from an ∼18 km long section of the northern East Pacific Rise (EPR) from 9°46′N to 9°56′N during 2005–2006 provide unique data pertaining to the short-term thermochemical changes in a mid-ocean ridge magmatic system. The 2005–2006 lavas are typical normal mid-oceanic ridge basalt with strongly depleted incompatible trace element patterns with marked negative Sr and Eu/Eu* anomalies and are slightly more evolved than lavas erupted in 1991–1992 at the same location on the EPR. Spatial geochemical differences show that lavas from the northern and southern limits of the 2005–2006 eruption are more evolved than those erupted in the central portion of the fissure system. Similar spatial patterns observed in 1991–1992 lavas suggest geochemical gradients are preserved over decadal time scales. Products of northern axial and off-axis fissure eruptions are consistent with the eruption of cooler, more fractionated lavas that also record a parental melt component not observed in the main suite of 2005–2006 lavas. Radiogenic isotopic ratios for 2005–2006 lavas fall within larger isotopic fields defined for young axial lavas from 9°N to 10°N EPR, including those from the 1991–1992 eruption. Geochemical data from the 2005–2006 eruption are consistent with an invariable mantle source over the spatial extent of the eruption and petrogenetic processes (e.g., fractional crystallization and magma mixing) operating within the crystal mush zone and axial magma chamber (AMC) before and during the 13 year repose period. Geochemical modeling suggests that the 2005–2006 lavas represent differentiated residual liquids from the 1991–1992 eruption that were modified by melts added from deeper within the crust and that the eruption was not initiated by the injection of hotter, more primitive basalt directly into the AMC. Rather, the eruption was driven by AMC pressurization from persistent or episodic addition of more evolved magma from the crystal mush zone into the overlying subridge AMC during the period between the two eruptions. Heat balance calculations of a hydrothermally cooled AMC support this model and show that continual addition of melt from the mush zone was required to m