Macrofaunal community structure and sulfide flux at gas hydrate deposits from the Cascadia convergent margin, NE Pacific

Sahling, Heiko; Rickert, Dirk; Lee, Raymond W.; Линке, Петер; Suess, Erwin

doi:10.3354/meps231121

Cited by 298 publications

(424 citation statements)

References 37 publications

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“…2 and Table S1). These forms are metazoan extremophiles and are characteristic of the most sulfiderich, methane-rich, and oxygen-poor environments of modern continental margins (35)(36)(37). Many of these extremophiles are opportunistic, weedy species and appear in high-density (∼900 individuals/m 2 ) zonations on modern continental margins (22,(38)(39)(40).…”

Section: Mv0811-15jc Biotic Recordmentioning

confidence: 99%

Response of seafloor ecosystems to abrupt global climate change

Moffitt

Hill

Roopnarine

et al. 2015

Proc. Natl. Acad. Sci. U.S.A.

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Anthropogenic climate change is predicted to decrease oceanic oxygen (O 2 ) concentrations, with potentially significant effects on marine ecosystems. Geologically recent episodes of abrupt climatic warming provide opportunities to assess the effects of changing oxygenation on marine communities. Thus far, this knowledge has been largely restricted to investigations using Foraminifera, with little being known about ecosystem-scale responses to abrupt, climate-forced deoxygenation. We here present high-resolution records based on the first comprehensive quantitative analysis, to our knowledge, of changes in marine metazoans (Mollusca, Echinodermata, Arthropoda, and Annelida; >5,400 fossils and trace fossils) in response to the global warming associated with the last glacial to interglacial episode. The molluscan archive is dominated by extremophile taxa, including those containing endosymbiotic sulfur-oxidizing bacteria (Lucinoma aequizonatum) and those that graze on filamentous sulfur-oxidizing benthic bacterial mats (Alia permodesta). This record, from 16,100 to 3,400 y ago, demonstrates that seafloor invertebrate communities are subject to major turnover in response to relatively minor inferred changes in oxygenation (>1.5 to <0.5 mL·L −1 [O 2 ]) associated with abrupt (<100 y) warming of the eastern Pacific. The biotic turnover and recovery events within the record expand known rates of marine biological recovery by an order of magnitude, from <100 to >1,000 y, and illustrate the crucial role of climate and oceanographic change in driving long-term successional changes in ocean ecosystems.seafloor ecosystems | abrupt climate change | deglaciation | oxygen minimum zone | metazoans O ceanic deoxygenation is a predictable, fundamental, and long-lasting property of anthropogenic climate change (1). The global ocean inventory of oxygen is predicted to decline between 1% and 7% by the year 2100, and modeling predictions reveal extensive oceanic deoxygenation, on thousand-year timescales, under "business-as-usual" carbon emission scenarios (2). Modern oceanographic time series already document rapid loss of [O 2 ] in interior ocean waters over the last 4 decades (3, 4), although this trend is complicated in regions where [O 2 ] demand is decreased through the slackening of trade winds (5). As oxygen levels in the ocean decrease and the already extensive oxygen minimum zones (OMZs) expand, the volumetric habitat for aerobic respiration is reduced, presumably resulting in a fundamental reorganization of marine communities. Past events of climate warming and OMZ expansion, including the recent deglaciation from 18 to 11 ka, provide a case study for understanding the effects on marine ecosystems of abrupt temperature and oxygenation changes.Paleoceanographic records clearly demonstrate that OMZ strength changed in response to

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Section: Mv0811-15jc Biotic Recordmentioning

confidence: 99%

Response of seafloor ecosystems to abrupt global climate change

Moffitt

Hill

Roopnarine

et al. 2015

Proc. Natl. Acad. Sci. U.S.A.

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“…Gas seeps are defined by the source and composition of the gas feeding the seep, with biologically generated gas consisting almost entirely of methane, and thermally generated gas often consisting of methane with moderate levels of carbon dioxide, ethane, propane, and butane. Hydrocarbon seeps have been the subject of intense recent study, particularly on account of their interesting ecology, and their role in the marine methane and carbon cycle (Orphan et al 2002;Sahling et al 2002;Boetius and Suess 2004;Levin 2005;Reeburgh 2007). The amount of fossil, radiocarbon-free methane in the atmosphere suggests that natural emission from geological sources (seeps) is significant and possibly underestimated (Etiope et al 2008).…”

Section: Introductionmentioning

confidence: 99%

Gas flux and carbonate occurrence at a shallow seep of thermogenic natural gas

et al. 2010

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The Coal Oil Point seep field located offshore Santa Barbara, CA, consists of dozens of named seeps, including a peripheral ∼200 m 2 area known as Brian Seep, located in 10 m water depth. A single comprehensive survey of gas flux at Brian Seep yielded a methane release rate of ∼450 moles of CH 4 per day, originating from 68 persistent gas vents and 23 intermittent vents, with gas flux among persistent vents displaying a log normal frequency distribution. A subsequent series of 33 repeat surveys conducted over a period of 6 months tracked eight persistent vents, and revealed substantial temporal variability in gas venting, with flux from each individual vent varying by more than a factor of 4. During wintertime surveys sediment was largely absent from the site, and carbonate concretions were exposed at the seafloor. The presence of the carbonates was unexpected, as the thermogenic seep gas contains 6.7% CO 2 , which should act to dissolve carbonates. The average δ 13 C of the carbonates was −29.2±2.8‰ VPDB, compared to a range of −1.0 to +7.8‰ for CO 2 in the seep gas, indicating that CO 2 from the seep gas is quantitatively not as important as 13 Cdepleted bicarbonate derived from methane oxidation. Methane, with a δ 13 C of approximately −43‰, is oxidized and the resulting inorganic carbon precipitates as highmagnesium calcite and other carbonate minerals. This finding is supported by 13 C-depleted biomarkers typically associated with anaerobic methanotrophic archaea and their bacterial syntrophic partners in the carbonates (lipid biomarker δ 13 C ranged from −84 to −25‰). The inconsistency in δ 13 C between the carbonates and the seeping CO 2 was resolved by discovering pockets of gas trapped near the base of the sediment column with δ 13 C-CO 2 values ranging from −26.9 to −11.6‰. A mechanism of carbonate formation is proposed in which carbonates form near the sediment-bedrock interface during times of sufficient sediment coverage, in which anaerobic oxidation of methane is favored. Precipitation occurs at a sufficient distance from active venting for the molecular and isotopic composition of seep gas to be masked by the generation of carbonate alkalinity from anaerobic methane oxidation.

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“…These chemosynthetic communities demonstrate the presence of hydrocarbon gas seeps that are often associated with gas hydrate deposits 38,39 . No evidence has been found for the presence of volcanic hydrothermal systems in the Hota group because this area was far away from the volcanic front at the time of sedimentation.…”

Section: Discussionmentioning

confidence: 99%

“…Therefore, mud volcanoes are situated in active areas of plate boundaries and in zones of young orogenic structures. Thermogenic gas hydrate deposits are abundantly distributed in these active areas in association with faults and mud volcanoes 36 ; for example, the Gulf of Mexico 16,17,39 , the Cascadia margin 12,38 , the Black Sea 42 , the Barbados accretionary prism 34 , the Costa Rica forearc 48 , the Gulf of Cadiz 35 and the Mediterranean Sea 49 . Accordingly, hydrocarbons contained in thermogenic gas hydrates and those contained in chibaite and DOH-type mineral are of the common origin, which is the thermal decomposition of organic matter in deep sediments.…”

Section: Discussionmentioning

confidence: 99%

New silica clathrate minerals that are isostructural with natural gas hydrates

Momma

Ikeda

Nishikubo³

et al. 2011

Nat Commun

128

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silica clathrate compounds (clathrasils) and clathrate hydrates are structurally analogous because both materials have framework structures with cage-like voids occupied by guest species. The following three structural types of clathrate hydrates are recognized in nature: cubic structure I (sI); cubic structure II (sII); and hexagonal structure H (sH). In contrast, only one naturally occurring silica clathrate mineral, melanophlogite (sI-type framework), has been found to date. Here, we report the discovery of two new silica clathrate minerals that are isostructural with sII and sH hydrates and contain hydrocarbon gases. Geological and mineralogical observations show that these silica clathrate minerals are traces of lowtemperature hydrothermal systems at convergent plate margins, which are the sources of thermogenic natural gas hydrates. Given the widespread occurrence of submarine hydrocarbon seeps, silica clathrate minerals are likely to be found in a wide range of marine sediments.

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Macrofaunal community structure and sulfide flux at gas hydrate deposits from the Cascadia convergent margin, NE Pacific

Cited by 298 publications

References 37 publications

Response of seafloor ecosystems to abrupt global climate change

Response of seafloor ecosystems to abrupt global climate change

Gas flux and carbonate occurrence at a shallow seep of thermogenic natural gas

New silica clathrate minerals that are isostructural with natural gas hydrates

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