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Schroedl P, Silverstein M, DiGregorio D, Blättler CL, Loyd S, Bradbury HJ, Edwards RL, Marlow J. Carbonate chimneys at the highly productive point Dume methane seep: Fine-scale mineralogical, geochemical, and microbiological heterogeneity reflects dynamic and long-lived methane-metabolizing habitats. GEOBIOLOGY 2024; 22:e12608. [PMID: 38946067 DOI: 10.1111/gbi.12608] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/27/2023] [Revised: 05/24/2024] [Accepted: 06/12/2024] [Indexed: 07/02/2024]
Abstract
Methane is a potent greenhouse gas that enters the marine system in large quantities at seafloor methane seeps. At a newly discovered seep site off the coast of Point Dume, CA, ~ meter-scale carbonate chimneys host microbial communities that exhibit the highest methane-oxidizing potential recorded to date. Here, we provide a detailed assessment of chimney geobiology through correlative mineralogical, geochemical, and microbiological studies of seven chimney samples in order to clarify the longevity and heterogeneity of these highly productive systems. U-Th dating indicated that a methane-driven carbonate precipitating system at Point Dume has existed for ~20 Kyr, while millimeter-scale variations in carbon and calcium isotopic values, elemental abundances, and carbonate polymorphs revealed changes in carbon source, precipitation rates, and diagenetic processes throughout the chimneys' lifespan. Microbial community analyses revealed diverse modern communities with prominent anaerobic methanotrophs, sulfate-reducing bacteria, and Anaerolineaceae; communities were more similar within a given chimney wall transect than in similar horizons of distinct structures. The chimneys represent long-lived repositories of methane-oxidizing communities and provide a window into how carbon can be transformed, sequestered, and altered over millennia at the Point Dume methane seep.
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Affiliation(s)
- Peter Schroedl
- Department of Biology, Boston University, Boston, Massachusetts, USA
| | | | - Daisy DiGregorio
- Department of Biology, Boston University, Boston, Massachusetts, USA
| | - Clara L Blättler
- Department of the Geophysical Sciences, University of Chicago, Chicago, Illinois, USA
| | - Sean Loyd
- Department of Geological Sciences, California State University Fullerton, Fullerton, California, USA
| | - Harold J Bradbury
- Department of Earth, Ocean and Atmospheric Sciences, University of British Columbia, Vancouver, British Columbia, Canada
| | - R Lawrence Edwards
- Department of Earth and Environmental Science, University of Minnesota, Minneapolis, Minnesota, USA
| | - Jeffrey Marlow
- Department of Biology, Boston University, Boston, Massachusetts, USA
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2
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Assessing the Benthic Response to Climate-Driven Methane Hydrate Destabilisation: State of the Art and Future Modelling Perspectives. ENERGIES 2022. [DOI: 10.3390/en15093307] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Modern observations and geological records suggest that anthropogenic ocean warming could destabilise marine methane hydrate, resulting in methane release from the seafloor to the ocean-atmosphere, and potentially triggering a positive feedback on global temperature. On the decadal to millennial timescales over which hydrate-sourced methane release is hypothesized to occur, several processes consuming methane below and above the seafloor have the potential to slow, reduce or even prevent such release. Yet, the modulating effect of these processes on seafloor methane emissions remains poorly quantified, and the full impact of benthic methane consumption on ocean carbon chemistry is still to be explored. In this review, we document the dynamic interplay between hydrate thermodynamics, benthic transport and biogeochemical reaction processes, that ultimately determines the impact of hydrate destabilisation on seafloor methane emissions and the ocean carbon cycle. Then, we provide an overview of how state-of-the-art numerical models treat such processes and examine their ability to quantify hydrate-sourced methane emissions from the seafloor, as well as their impact on benthic biogeochemical cycling. We discuss the limitations of current models in coupling the dynamic interplay between hydrate thermodynamics and the different reaction and transport processes that control the efficiency of the benthic sink, and highlight their shortcoming in assessing the full implication of methane release on ocean carbon cycling. Finally, we recommend that current Earth system models explicitly account for hydrate driven benthic-pelagic exchange fluxes to capture potential hydrate-carbon cycle-climate feed-backs.
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3
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Argentino C, Waghorn KA, Vadakkepuliyambatta S, Polteau S, Bünz S, Panieri G. Dynamic and history of methane seepage in the SW Barents Sea: new insights from Leirdjupet Fault Complex. Sci Rep 2021; 11:4373. [PMID: 33623088 PMCID: PMC7902819 DOI: 10.1038/s41598-021-83542-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2020] [Accepted: 02/03/2021] [Indexed: 01/31/2023] Open
Abstract
Methane emissions from Arctic continental margins are increasing due to the negative effect of global warming on ice sheet and permafrost stability, but dynamics and timescales of seafloor seepage still remain poorly constrained. Here, we examine sediment cores collected from an active seepage area located between 295 and 353 m water depth in the SW Barents Sea, at Leirdjupet Fault Complex. The geochemical composition of hydrocarbon gas in the sediment indicates a mixture of microbial and thermogenic gas, the latter being sourced from underlying Mesozoic formations. Sediment and carbonate geochemistry reveal a long history of methane emissions that started during Late Weichselian deglaciation after 14.5 cal ka BP. Methane-derived authigenic carbonates precipitated due to local gas hydrate destabilization, in turn triggered by an increasing influx of warm Atlantic water and isostatic rebound linked to the retreat of the Barents Sea Ice Sheet. This study has implications for a better understanding of the dynamic and future evolution of methane seeps in modern analogue systems in Western Antarctica, where the retreat of marine-based ice sheet induced by global warming may cause the release of large amounts of methane from hydrocarbon reservoirs and gas hydrates.
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Affiliation(s)
- Claudio Argentino
- CAGE - Centre for Arctic Gas Hydrate, Environment and Climate, Department of Geosciences, UiT The Arctic University of Norway, 9037, Tromsø, Norway.
| | - Kate Alyse Waghorn
- CAGE - Centre for Arctic Gas Hydrate, Environment and Climate, Department of Geosciences, UiT The Arctic University of Norway, 9037, Tromsø, Norway
| | - Sunil Vadakkepuliyambatta
- CAGE - Centre for Arctic Gas Hydrate, Environment and Climate, Department of Geosciences, UiT The Arctic University of Norway, 9037, Tromsø, Norway
| | - Stéphane Polteau
- Oslo Innovation Center, VBPR - Volcanic Basin Petroleum Research, 0349, Oslo, Norway
- Institute for Energy Technology, 2007, Kjeller, Norway
- SurfExGeo, 0776, Oslo, Norway
| | - Stefan Bünz
- CAGE - Centre for Arctic Gas Hydrate, Environment and Climate, Department of Geosciences, UiT The Arctic University of Norway, 9037, Tromsø, Norway
| | - Giuliana Panieri
- CAGE - Centre for Arctic Gas Hydrate, Environment and Climate, Department of Geosciences, UiT The Arctic University of Norway, 9037, Tromsø, Norway
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4
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Methane Derived Authigenic Carbonate (MDAC) Aragonite Cemented Quaternary Hardground from a Methane Cold Seep, Rathlin Basin, Northern Ireland: δ13C and δ18O Isotopes, Environment, Porosity and Permeability. GEOSCIENCES 2020. [DOI: 10.3390/geosciences10070255] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
A block of sandstone retrieved by divers from near Rathlin Island, Co. Antrim, Northern Ireland, represents an aragonite cemented sand formed during the Quaternary. Strongly negative δ13C of the aragonite cement (−50 to −60‰ δ13C) indicates that the hardground was formed by the anaerobic oxidation of methane (AOM), resulting in the formation of a methane-derived authigenic carbonate (MDAC) hardground. Such hardgrounds have previously been recorded as forming extensive pavements in deeper waters in the mid Irish Sea (e.g., Croker Carbonate Slabs), although the latter also contains high-magnesium calcite. Sand was initially deposited as part of a storm lag deposit, with a reworked bivalve and gastropod fauna. This sand was then colonised by a probable crustacean fauna, producing horizontal open dwelling burrows (Thalassinoides). After aragonite cementation, the hardground was colonised by boring bivalves, with slightly negatively elevated levels of δ13C. Finally, the hardground was colonised by an encrusting fauna (bryozoans, calcareous algae and serpulids), by then in warmer seas. Continued depleted levels of δ13C present within the encrusting fauna (−1 to −5‰ δ13C) indicate continued methane generation and seepage, which may still be active to the present day, and to the possibility of shallow gas reserves. The δ18O values change between macro-infauna vs. encrusters, indicating a warming in water temperature, reflecting glacial and post-glacial environments. The aragonite cemented sandstone has a highly variable porosity, with large vugs (open burrows and borings), smaller mouldic porosity within gastropods and bivalves and complex micro-porosity associated with acicular aragonite cements. Overall permeability was recorded at the 2.5 to 23 Darcies level, reflecting the highly variable vuggy porosity, although matrix permeability was around 100 mD and controlled by the MDAC fabric. Actual permeability will likely be controlled by the extent to which larger pores are interconnected. The sea around the Rathlin Island area contains a diverse fauna, which is worthy of future study in the context of cold seep and MDAC pavement formation.
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The benthic foraminiferal δ 34S records flux and timing of paleo methane emissions. Sci Rep 2020; 10:1304. [PMID: 31992778 PMCID: PMC6987089 DOI: 10.1038/s41598-020-58353-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2019] [Accepted: 01/13/2020] [Indexed: 11/10/2022] Open
Abstract
In modern environments, pore water geochemistry and modelling simulations allow the study of methane (CH4) sources and sinks at any geographic location. However, reconstructing CH4 dynamics in geological records is challenging. Here, we show that the benthic foraminiferal δ34S can be used to reconstruct the flux (i.e., diffusive vs. advective) and timing of CH4 emissions in fossil records. We measured the δ34S of Cassidulina neoteretis specimens from selected samples collected at Vestnesa Ridge, a methane cold seep site in the Arctic Ocean. Our results show lower benthic foraminiferal δ34S values (∼20‰) in the sample characterized by seawater conditions, whereas higher values (∼25–27‰) were measured in deeper samples as a consequence of the presence of past sulphate-methane transition zones. The correlation between δ34S and the bulk benthic foraminiferal δ13C supports this interpretation, whereas the foraminiferal δ18O-δ34S correlation indicates CH4 advection at the studied site during the Early Holocene and the Younger-Dryas – post-Bølling. This study highlights the potential of the benthic foraminiferal δ34S as a novel tool to reconstruct the flux of CH4 emissions in geological records and to indirectly date fossil seeps.
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Wadham JL, Hawkings JR, Tarasov L, Gregoire LJ, Spencer RGM, Gutjahr M, Ridgwell A, Kohfeld KE. Ice sheets matter for the global carbon cycle. Nat Commun 2019; 10:3567. [PMID: 31417076 PMCID: PMC6695407 DOI: 10.1038/s41467-019-11394-4] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2017] [Accepted: 07/09/2019] [Indexed: 11/09/2022] Open
Abstract
The cycling of carbon on Earth exerts a fundamental influence upon the greenhouse gas content of the atmosphere, and hence global climate over millennia. Until recently, ice sheets were viewed as inert components of this cycle and largely disregarded in global models. Research in the past decade has transformed this view, demonstrating the existence of uniquely adapted microbial communities, high rates of biogeochemical/physical weathering in ice sheets and storage and cycling of organic carbon (>104 Pg C) and nutrients. Here we assess the active role of ice sheets in the global carbon cycle and potential ramifications of enhanced melt and ice discharge in a warming world.
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Affiliation(s)
- J L Wadham
- University of Bristol, Bristol, BS8 1TH, UK.
| | - J R Hawkings
- National High Magnetic Field Lab and Earth, Ocean and Atmospheric Sciences, Florida State University, Tallahassee, FL, 32306, USA
- German Research Centre for Geosciences GFZ, 14473, Potsdam, Germany
| | - L Tarasov
- Memorial University, St. John's, NF, A1B 3X9, Canada
| | | | - R G M Spencer
- National High Magnetic Field Lab and Earth, Ocean and Atmospheric Sciences, Florida State University, Tallahassee, FL, 32306, USA
| | | | - A Ridgwell
- University of California, Riverside, CA, 94720, USA
| | - K E Kohfeld
- Simon Fraser University, Burnaby, BC, 8888, Canada
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7
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Sen A, Chitkara C, Hong WL, Lepland A, Cochrane S, di Primio R, Brunstad H. Image based quantitative comparisons indicate heightened megabenthos diversity and abundance at a site of weak hydrocarbon seepage in the southwestern Barents Sea. PeerJ 2019; 7:e7398. [PMID: 31410307 PMCID: PMC6689391 DOI: 10.7717/peerj.7398] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2019] [Accepted: 07/02/2019] [Indexed: 11/30/2022] Open
Abstract
BACKGROUND High primary productivity in the midst of high toxicity defines hydrocarbon seeps; this feature usually results in significantly higher biomass, but in lower diversity communities at seeps rather than in the surrounding non-seep benthos. Qualitative estimates indicate that this dichotomy does not necessarily hold true in high latitude regions with respect to megafauna. Instead, high latitude seeps appear to function as local hotspots of both megafaunal diversity and abundance, although quantitative studies do not exist. In this study, we tested this hypothesis quantitatively by comparing georeferenced seafloor mosaics of a seep in the southwestern Barents Sea with the adjacent non-seep seafloor. METHODS Seafloor images of the Svanefjell seep site and the adjacent non seep-influenced background seabed in the southwestern Barents Sea were used to construct georeferenced mosaics. All megafauna were enumerated and mapped on these mosaics and comparisons of the communities at the seep site and the non-seep background site were compared. Sediment push cores were taken in order to assess the sediment geochemical environment. RESULTS Taxonomic richness and abundance were both considerably higher at the seep site than the non-seep location. However, taxa were fewer at the seep site compared to other seeps in the Barents Sea or the Arctic, which is likely due to the Svanefjell seep site exhibiting relatively low seepage rates (and correspondingly less chemosynthesis based primary production). Crusts of seep carbonates account for the higher diversity of the seep site compared to the background site, since most animals were either colonizing crust surfaces or using them for shelter or coverage. Our results indicate that seeps in northern latitudes can enhance local benthic diversity and this effect can take place even with weak seepage. Since crusts of seep carbonates account for most of the aggregating effect of sites experiencing moderate/weak seepage such as the study site, this means that the ability of seep sites to attract benthic species extends well beyond the life cycle of the seep itself, which has important implications for the larger marine ecosystem and its management policies.
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Affiliation(s)
- Arunima Sen
- UiT The Arctic University of Norway, Centre for Arctic Gas Hydrate, Environment and Climate (CAGE), Tromsø, Norway
- Current affiliation: Faculty of Biosciences and Aquaculture, Nord University, Bodø, Norway
| | - Cheshtaa Chitkara
- UiT The Arctic University of Norway, Centre for Arctic Gas Hydrate, Environment and Climate (CAGE), Tromsø, Norway
| | - Wei-Li Hong
- Geological Survey of Norway (NGU), Trondheim, Norway
| | - Aivo Lepland
- Geological Survey of Norway (NGU), Trondheim, Norway
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8
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Himmler T, Sahy D, Martma T, Bohrmann G, Plaza-Faverola A, Bünz S, Condon DJ, Knies J, Lepland A. A 160,000-year-old history of tectonically controlled methane seepage in the Arctic. SCIENCE ADVANCES 2019; 5:eaaw1450. [PMID: 31457082 PMCID: PMC6685712 DOI: 10.1126/sciadv.aaw1450] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/21/2018] [Accepted: 06/28/2019] [Indexed: 06/10/2023]
Abstract
The geological factors controlling gas release from Arctic deep-water gas reservoirs through seabed methane seeps are poorly constrained. This is partly due to limited data on the precise chronology of past methane emission episodes. Here, we use uranium-thorium dating of seep carbonates sampled from the seabed and from cores drilled at the Vestnesa Ridge, off West Svalbard (79°N, ~1200 m water depth). The carbonate ages reveal three emission episodes during the Penultimate Glacial Maximum (~160,000 to 133,000 years ago), during an interstadial in the last glacial (~50,000 to 40,000 years ago), and in the aftermath of the Last Glacial Maximum (~20,000 to 5,000 years ago), respectively. This chronology suggests that glacial tectonics induced by ice sheet fluctuations on Svalbard mainly controlled methane release from Vestnesa Ridge. Data corroborate past methane release in response to Northern Hemisphere cryosphere variations and suggest that Arctic deep-water gas reservoirs are sensitive to temperature variations over Quaternary time scales.
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Affiliation(s)
- Tobias Himmler
- Geological Survey of Norway, P.O. Box 6315 Torgarden, 7491 Trondheim, Norway
- Centre for Arctic Gas Hydrate, Environment and Climate, Department of Geosciences, UiT The Arctic University of Norway, Tromsø, Norway
| | - Diana Sahy
- British Geological Survey, Keyworth, Nottingham NG12 5GG, UK
| | - Tõnu Martma
- Department of Geology, Tallinn University of Technology, Tallinn, Estonia
| | - Gerhard Bohrmann
- MARUM–Center for Marine and Environmental Sciences and Department of Geosciences, University of Bremen, 28334 Bremen, Germany
| | - Andreia Plaza-Faverola
- Centre for Arctic Gas Hydrate, Environment and Climate, Department of Geosciences, UiT The Arctic University of Norway, Tromsø, Norway
| | - Stefan Bünz
- Centre for Arctic Gas Hydrate, Environment and Climate, Department of Geosciences, UiT The Arctic University of Norway, Tromsø, Norway
| | | | - Jochen Knies
- Geological Survey of Norway, P.O. Box 6315 Torgarden, 7491 Trondheim, Norway
- Centre for Arctic Gas Hydrate, Environment and Climate, Department of Geosciences, UiT The Arctic University of Norway, Tromsø, Norway
| | - Aivo Lepland
- Geological Survey of Norway, P.O. Box 6315 Torgarden, 7491 Trondheim, Norway
- Centre for Arctic Gas Hydrate, Environment and Climate, Department of Geosciences, UiT The Arctic University of Norway, Tromsø, Norway
- Department of Geology, Tallinn University of Technology, Tallinn, Estonia
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9
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A Quick-Look Method for Initial Evaluation of Gas Hydrate Stability below Subaqueous Permafrost. GEOSCIENCES 2019. [DOI: 10.3390/geosciences9080329] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Many studies demonstrated the coexistence of subaqueous permafrost and gas hydrate. Subaqueous permafrost could be a factor affecting the formation/dissociation of gas hydrate. Here, we propose a simple empirical approach that allows estimating the steady-state conditions for gas hydrate stability in the presence of subaqueous permafrost. This approach was derived for pressure, temperature, and salinity conditions typical of subaqueous permafrost in marine (brine) and lacustrine (freshwater) environments.
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10
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Andreassen K, Hubbard A, Winsborrow M, Patton H, Vadakkepuliyambatta S, Plaza-Faverola A, Gudlaugsson E, Serov P, Deryabin A, Mattingsdal R, Mienert J, Bünz S. Massive blow-out craters formed by hydrate-controlled methane expulsion from the Arctic seafloor. Science 2018; 356:948-953. [PMID: 28572390 DOI: 10.1126/science.aal4500] [Citation(s) in RCA: 134] [Impact Index Per Article: 22.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2016] [Accepted: 05/11/2017] [Indexed: 11/02/2022]
Abstract
Widespread methane release from thawing Arctic gas hydrates is a major concern, yet the processes, sources, and fluxes involved remain unconstrained. We present geophysical data documenting a cluster of kilometer-wide craters and mounds from the Barents Sea floor associated with large-scale methane expulsion. Combined with ice sheet/gas hydrate modeling, our results indicate that during glaciation, natural gas migrated from underlying hydrocarbon reservoirs and was sequestered extensively as subglacial gas hydrates. Upon ice sheet retreat, methane from this hydrate reservoir concentrated in massive mounds before being abruptly released to form craters. We propose that these processes were likely widespread across past glaciated petroleum provinces and that they also provide an analog for the potential future destabilization of subglacial gas hydrate reservoirs beneath contemporary ice sheets.
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Affiliation(s)
- K Andreassen
- Centre for Arctic Gas Hydrate, Environment and Climate (CAGE), Department of Geosciences, UiT The Arctic University of Norway, N-9037 Tromsø, Norway.
| | - A Hubbard
- Centre for Arctic Gas Hydrate, Environment and Climate (CAGE), Department of Geosciences, UiT The Arctic University of Norway, N-9037 Tromsø, Norway
| | - M Winsborrow
- Centre for Arctic Gas Hydrate, Environment and Climate (CAGE), Department of Geosciences, UiT The Arctic University of Norway, N-9037 Tromsø, Norway
| | - H Patton
- Centre for Arctic Gas Hydrate, Environment and Climate (CAGE), Department of Geosciences, UiT The Arctic University of Norway, N-9037 Tromsø, Norway
| | - S Vadakkepuliyambatta
- Centre for Arctic Gas Hydrate, Environment and Climate (CAGE), Department of Geosciences, UiT The Arctic University of Norway, N-9037 Tromsø, Norway
| | - A Plaza-Faverola
- Centre for Arctic Gas Hydrate, Environment and Climate (CAGE), Department of Geosciences, UiT The Arctic University of Norway, N-9037 Tromsø, Norway
| | - E Gudlaugsson
- Centre for Arctic Gas Hydrate, Environment and Climate (CAGE), Department of Geosciences, UiT The Arctic University of Norway, N-9037 Tromsø, Norway
| | - P Serov
- Centre for Arctic Gas Hydrate, Environment and Climate (CAGE), Department of Geosciences, UiT The Arctic University of Norway, N-9037 Tromsø, Norway
| | - A Deryabin
- Norwegian Petroleum Directorate, Harstad, Norway
| | | | - J Mienert
- Centre for Arctic Gas Hydrate, Environment and Climate (CAGE), Department of Geosciences, UiT The Arctic University of Norway, N-9037 Tromsø, Norway
| | - S Bünz
- Centre for Arctic Gas Hydrate, Environment and Climate (CAGE), Department of Geosciences, UiT The Arctic University of Norway, N-9037 Tromsø, Norway
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11
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Riboulot V, Ker S, Sultan N, Thomas Y, Marsset B, Scalabrin C, Ruffine L, Boulart C, Ion G. Freshwater lake to salt-water sea causing widespread hydrate dissociation in the Black Sea. Nat Commun 2018; 9:117. [PMID: 29317616 PMCID: PMC5760725 DOI: 10.1038/s41467-017-02271-z] [Citation(s) in RCA: 43] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2016] [Accepted: 11/16/2017] [Indexed: 11/12/2022] Open
Abstract
Gas hydrates, a solid established by water and gas molecules, are widespread along the continental margins of the world. Their dynamics have mainly been regarded through the lens of temperature-pressure conditions. A fluctuation in one of these parameters may cause destabilization of gas hydrate-bearing sediments below the seafloor with implications in ocean acidification and eventually in global warming. Here we show throughout an example of the Black Sea, the world’s most isolated sea, evidence that extensive gas hydrate dissociation may occur in the future due to recent salinity changes of the sea water. Recent and forthcoming salt diffusion within the sediment will destabilize gas hydrates by reducing the extension and thickness of their thermodynamic stability zone in a region covering at least 2800 square kilometers which focus seepages at the observed sites. We suspect this process to occur in other world regions (e.g., Caspian Sea, Sea of Marmara). Gas hydrates are maintained via a balance of temperature and pressure, if this changes then destabilization may occur. Here, the authors show instead that due to recent changes in the salinity of the sea water of the Black Sea, gas hydrates may become destabilized with widespread methane seepage.
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Affiliation(s)
| | - Stephan Ker
- IFREMER, REM-GM, BP70, 29280, Plouzané, France
| | | | | | | | | | | | | | - Gabriel Ion
- National Institute of Marine Geology and Geo-ecology, RO-024053, Bucharest, Romania
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12
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Wallmann K, Riedel M, Hong WL, Patton H, Hubbard A, Pape T, Hsu CW, Schmidt C, Johnson JE, Torres ME, Andreassen K, Berndt C, Bohrmann G. Gas hydrate dissociation off Svalbard induced by isostatic rebound rather than global warming. Nat Commun 2018; 9:83. [PMID: 29311564 PMCID: PMC5758787 DOI: 10.1038/s41467-017-02550-9] [Citation(s) in RCA: 73] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2017] [Accepted: 12/07/2017] [Indexed: 11/25/2022] Open
Abstract
Methane seepage from the upper continental slopes of Western Svalbard has previously been attributed to gas hydrate dissociation induced by anthropogenic warming of ambient bottom waters. Here we show that sediment cores drilled off Prins Karls Foreland contain freshwater from dissociating hydrates. However, our modeling indicates that the observed pore water freshening began around 8 ka BP when the rate of isostatic uplift outpaced eustatic sea-level rise. The resultant local shallowing and lowering of hydrostatic pressure forced gas hydrate dissociation and dissolved chloride depletions consistent with our geochemical analysis. Hence, we propose that hydrate dissociation was triggered by postglacial isostatic rebound rather than anthropogenic warming. Furthermore, we show that methane fluxes from dissociating hydrates were considerably smaller than present methane seepage rates implying that gas hydrates were not a major source of methane to the oceans, but rather acted as a dynamic seal, regulating methane release from deep geological reservoirs. Methane seepage from continental slopes has been attributed to gas hydrate dissociation induced by anthropogenic bottom water warming. Here, the authors show that hydrates dissociated before the Anthropocene when the isostatic rebound induced by deglaciation of the Arctic ice sheet outpaced eustatic sea-level rise.
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Affiliation(s)
- Klaus Wallmann
- GEOMAR Helmholtz Centre for Ocean Research Kiel, Wischhofstr. 1-3, Kiel, 24148, Germany.
| | - M Riedel
- GEOMAR Helmholtz Centre for Ocean Research Kiel, Wischhofstr. 1-3, Kiel, 24148, Germany
| | - W L Hong
- Geological Survey of Norway, N-7022, Trondheim, Norway.,CAGE Centre for Arctic Gas Hydrate Research, Environment and Climate, Department of Geosciences, UiT-The Arctic University of Norway, Tromsø, N-9037, Norway
| | - H Patton
- CAGE Centre for Arctic Gas Hydrate Research, Environment and Climate, Department of Geosciences, UiT-The Arctic University of Norway, Tromsø, N-9037, Norway
| | - A Hubbard
- CAGE Centre for Arctic Gas Hydrate Research, Environment and Climate, Department of Geosciences, UiT-The Arctic University of Norway, Tromsø, N-9037, Norway.,Department of Geography & Earth Science, Aberystwyth University, Wales, SY23 3DB, UK
| | - T Pape
- MARUM-Center for Marine Environmental Sciences and Department of Geosciences, University of Bremen, Klagenfurter Str., Bremen, 28359, Germany
| | - C W Hsu
- MARUM-Center for Marine Environmental Sciences and Department of Geosciences, University of Bremen, Klagenfurter Str., Bremen, 28359, Germany
| | - C Schmidt
- GEOMAR Helmholtz Centre for Ocean Research Kiel, Wischhofstr. 1-3, Kiel, 24148, Germany
| | - J E Johnson
- Department of Earth Sciences, University of New Hampshire, 56 College Rd., Durham, NH, 03824-3589, USA
| | - M E Torres
- College of Oceanic and Atmospheric Sciences, Oregon State University, 104 Ocean Admin Building, Corvallis, OR, 97331-5503, USA
| | - K Andreassen
- CAGE Centre for Arctic Gas Hydrate Research, Environment and Climate, Department of Geosciences, UiT-The Arctic University of Norway, Tromsø, N-9037, Norway
| | - C Berndt
- GEOMAR Helmholtz Centre for Ocean Research Kiel, Wischhofstr. 1-3, Kiel, 24148, Germany
| | - G Bohrmann
- MARUM-Center for Marine Environmental Sciences and Department of Geosciences, University of Bremen, Klagenfurter Str., Bremen, 28359, Germany
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13
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Hong WL, Torres ME, Carroll J, Crémière A, Panieri G, Yao H, Serov P. Seepage from an arctic shallow marine gas hydrate reservoir is insensitive to momentary ocean warming. Nat Commun 2017; 8:15745. [PMID: 28589962 PMCID: PMC5477557 DOI: 10.1038/ncomms15745] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2016] [Accepted: 04/25/2017] [Indexed: 11/09/2022] Open
Abstract
Arctic gas hydrate reservoirs located in shallow water and proximal to the sediment-water interface are thought to be sensitive to bottom water warming that may trigger gas hydrate dissociation and the release of methane. Here, we evaluate bottom water temperature as a potential driver for hydrate dissociation and methane release from a recently discovered, gas-hydrate-bearing system south of Spitsbergen (Storfjordrenna, ∼380 m water depth). Modelling of the non-steady-state porewater profiles and observations of distinct layers of methane-derived authigenic carbonate nodules in the sediments indicate centurial to millennial methane emissions in the region. Results of temperature modelling suggest limited impact of short-term warming on gas hydrates deeper than a few metres in the sediments. We conclude that the ongoing and past methane emission episodes at the investigated sites are likely due to the episodic ventilation of deep reservoirs rather than warming-induced gas hydrate dissociation in this shallow water seep site.
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Affiliation(s)
- Wei-Li Hong
- CAGE-Centre for Arctic Gas Hydrate, Environment and Climate, Department of Geosciences, UiT The Arctic University of Norway, Tromsø N-9037, Norway
| | - Marta E Torres
- CEOAS, Oregon State University, Corvallis 97331, Oregon, USA
| | - JoLynn Carroll
- CAGE-Centre for Arctic Gas Hydrate, Environment and Climate, Department of Geosciences, UiT The Arctic University of Norway, Tromsø N-9037, Norway.,Akvaplan-niva AS, Fram Centre, Tromsø N-9296, Norway
| | | | - Giuliana Panieri
- CAGE-Centre for Arctic Gas Hydrate, Environment and Climate, Department of Geosciences, UiT The Arctic University of Norway, Tromsø N-9037, Norway
| | - Haoyi Yao
- CAGE-Centre for Arctic Gas Hydrate, Environment and Climate, Department of Geosciences, UiT The Arctic University of Norway, Tromsø N-9037, Norway
| | - Pavel Serov
- CAGE-Centre for Arctic Gas Hydrate, Environment and Climate, Department of Geosciences, UiT The Arctic University of Norway, Tromsø N-9037, Norway
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14
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Postglacial response of Arctic Ocean gas hydrates to climatic amelioration. Proc Natl Acad Sci U S A 2017; 114:6215-6220. [PMID: 28584081 DOI: 10.1073/pnas.1619288114] [Citation(s) in RCA: 65] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Seafloor methane release due to the thermal dissociation of gas hydrates is pervasive across the continental margins of the Arctic Ocean. Furthermore, there is increasing awareness that shallow hydrate-related methane seeps have appeared due to enhanced warming of Arctic Ocean bottom water during the last century. Although it has been argued that a gas hydrate gun could trigger abrupt climate change, the processes and rates of subsurface/atmospheric natural gas exchange remain uncertain. Here we investigate the dynamics between gas hydrate stability and environmental changes from the height of the last glaciation through to the present day. Using geophysical observations from offshore Svalbard to constrain a coupled ice sheet/gas hydrate model, we identify distinct phases of subglacial methane sequestration and subsequent release on ice sheet retreat that led to the formation of a suite of seafloor domes. Reconstructing the evolution of this dome field, we find that incursions of warm Atlantic bottom water forced rapid gas hydrate dissociation and enhanced methane emissions during the penultimate Heinrich event, the Bølling and Allerød interstadials, and the Holocene optimum. Our results highlight the complex interplay between the cryosphere, geosphere, and atmosphere over the last 30,000 y that led to extensive changes in subseafloor carbon storage that forced distinct episodes of methane release due to natural climate variability well before recent anthropogenic warming.
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15
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Himmler T, Bayon G, Wangner D, Enzmann F, Peckmann J, Bohrmann G. Seep-carbonate lamination controlled by cyclic particle flux. Sci Rep 2016; 6:37439. [PMID: 27876764 PMCID: PMC5120270 DOI: 10.1038/srep37439] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2016] [Accepted: 10/28/2016] [Indexed: 11/10/2022] Open
Abstract
Authigenic carbonate build-ups develop at seafloor methane-seeps, where microbially mediated sulphate-dependent anaerobic oxidation of methane facilitates carbonate precipitation. Despite being valuable recorders of past methane seepage events, their role as archives of atmospheric processes has not been examined. Here we show that cyclic sedimentation pulses related to the Indian monsoon in concert with authigenic precipitation of methane-derived aragonite gave rise to a well-laminated carbonate build-up within the oxygen minimum zone off Pakistan (northern Arabian Sea). U-Th dating indicates that the build-up grew during past ~1,130 years, creating an exceptional high-resolution archive of the Indian monsoon system. Monsoon-controlled formation of seep-carbonates extends the known environmental processes recorded by seep-carbonates, revealing a new relationship between atmospheric and seafloor processes.
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Affiliation(s)
- Tobias Himmler
- MARUM - Center for Marine and Environmental Sciences and Department of Geosciences, University of Bremen, 28334 Bremen, Germany.,IFREMER, Marine Geosciences Research Unit, Centre Bretagne, 29280 Plouzané, France
| | - Germain Bayon
- IFREMER, Marine Geosciences Research Unit, Centre Bretagne, 29280 Plouzané, France
| | - David Wangner
- MARUM - Center for Marine and Environmental Sciences and Department of Geosciences, University of Bremen, 28334 Bremen, Germany.,Geological Survey of Denmark and Greenland, DK-1350 Copenhagen K, Denmark
| | - Frieder Enzmann
- Institute of Geosciences, Johannes Gutenberg University Mainz, 55128 Mainz, Germany
| | - Jörn Peckmann
- Institute of Geology, University of Hamburg, 20146 Hamburg, Germany.,Department for Geodynamics and Sedimentology, University of Vienna, 1090 Vienna, Austria
| | - Gerhard Bohrmann
- MARUM - Center for Marine and Environmental Sciences and Department of Geosciences, University of Bremen, 28334 Bremen, Germany
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16
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Rush D, Osborne KA, Birgel D, Kappler A, Hirayama H, Peckmann J, Poulton SW, Nickel JC, Mangelsdorf K, Kalyuzhnaya M, Sidgwick FR, Talbot HM. The Bacteriohopanepolyol Inventory of Novel Aerobic Methane Oxidising Bacteria Reveals New Biomarker Signatures of Aerobic Methanotrophy in Marine Systems. PLoS One 2016; 11:e0165635. [PMID: 27824887 PMCID: PMC5100885 DOI: 10.1371/journal.pone.0165635] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2016] [Accepted: 10/15/2016] [Indexed: 12/24/2022] Open
Abstract
Aerobic methane oxidation (AMO) is one of the primary biologic pathways regulating the amount of methane (CH4) released into the environment. AMO acts as a sink of CH4, converting it into carbon dioxide before it reaches the atmosphere. It is of interest for (paleo)climate and carbon cycling studies to identify lipid biomarkers that can be used to trace AMO events, especially at times when the role of methane in the carbon cycle was more pronounced than today. AMO bacteria are known to synthesise bacteriohopanepolyol (BHP) lipids. Preliminary evidence pointed towards 35-aminobacteriohopane-30,31,32,33,34-pentol (aminopentol) being a characteristic biomarker for Type I methanotrophs. Here, the BHP compositions were examined for species of the recently described novel Type I methanotroph bacterial genera Methylomarinum and Methylomarinovum, as well as for a novel species of a Type I Methylomicrobium. Aminopentol was the most abundant BHP only in Methylomarinovum caldicuralii, while Methylomicrobium did not produce aminopentol at all. In addition to the expected regular aminotriol and aminotetrol BHPs, novel structures tentatively identified as methylcarbamate lipids related to C-35 amino-BHPs (MC-BHPs) were found to be synthesised in significant amounts by some AMO cultures. Subsequently, sediments and authigenic carbonates from methane-influenced marine environments were analysed. Most samples also did not contain significant amounts of aminopentol, indicating that aminopentol is not a useful biomarker for marine aerobic methanotophic bacteria. However, the BHP composition of the marine samples do point toward the novel MC-BHPs components being potential new biomarkers for AMO.
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Affiliation(s)
- Darci Rush
- School of Civil Engineering & Geosciences, Newcastle University, Drummond Building, Newcastle upon Tyne, NE1 7RU, Newcastle-upon-Tyne, United Kingdom
- * E-mail:
| | - Kate A. Osborne
- School of Civil Engineering & Geosciences, Newcastle University, Drummond Building, Newcastle upon Tyne, NE1 7RU, Newcastle-upon-Tyne, United Kingdom
| | - Daniel Birgel
- Institute of Geology, University of Hamburg, Hamburg, Germany
| | - Andreas Kappler
- Center for Applied Geoscience, University of Tübingen, Tübingen, Germany
- Center for Geomicrobiology, Department of Bioscience, Ny Munkegade 116, 8000, Aarhus C, Denmark
| | - Hisako Hirayama
- Department of Subsurface Geobiological Analysis and Research, Japan Agency for Marine-Earth Science & Technology (JAMSTEC), Yokosuka, Japan
| | - Jörn Peckmann
- Institute of Geology, University of Hamburg, Hamburg, Germany
- Department of Geodynamics and Sedimentology, University of Vienna, 1090, Vienna, Austria
| | - Simon W. Poulton
- School of Earth and Environment, University of Leeds, Leeds, LS2 9JT, United Kingdom
| | - Julia C. Nickel
- GFZ German Research Centre for Geosciences, Telegrafenberg, D-14473, Potsdam, Germany
| | - Kai Mangelsdorf
- GFZ German Research Centre for Geosciences, Telegrafenberg, D-14473, Potsdam, Germany
| | - Marina Kalyuzhnaya
- Faculty of Biology, San Diego State University, 5500 Campanile Drive, San Diego, 92182, United States of America
| | - Frances R. Sidgwick
- School of Civil Engineering & Geosciences, Newcastle University, Drummond Building, Newcastle upon Tyne, NE1 7RU, Newcastle-upon-Tyne, United Kingdom
| | - Helen M. Talbot
- School of Civil Engineering & Geosciences, Newcastle University, Drummond Building, Newcastle upon Tyne, NE1 7RU, Newcastle-upon-Tyne, United Kingdom
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