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Source apportionmen...
Source apportionment of methane escaping the subsea permafrost system in the outer Eurasian Arctic Shelf
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- Steinbach, Julia (author)
- Stockholms universitet,Institutionen för miljövetenskap,Institutionen för geologiska vetenskaper
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- Holmstrand, Henry (author)
- Stockholms universitet,Institutionen för miljövetenskap
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Shcherbakova, Kseniia (author)
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Kosmach, Denis (author)
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- Brüchert, Volker (author)
- Stockholms universitet,Institutionen för geologiska vetenskaper
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Shakhova, Natalia (author)
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Salyuk, Anatoly (author)
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Sapart, Celia J. (author)
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Chernykh, Denis (author)
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Noormets, Riko (author)
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Semiletov, Igor (author)
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- Gustafsson, Örjan (author)
- Stockholms universitet,Institutionen för miljövetenskap
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(creator_code:org_t)
- 2021-03
- 2021
- English.
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In: Proceedings of the National Academy of Sciences of the United States of America. - : Proceedings of the National Academy of Sciences. - 0027-8424 .- 1091-6490. ; 118:10
- Related links:
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https://doi.org/10.1...
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https://www.pnas.org...
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https://urn.kb.se/re...
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https://doi.org/10.1...
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Abstract
Subject headings
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- The East Siberian Arctic Shelf holds large amounts of inundated carbon and methane (CH4). Holocene warming by overlying seawater, recently fortified by anthropogenic warming, has caused thawing of the underlying subsea permafrost. Despite extensive observations of elevated seawater CH4 in the past decades, relative contributions from different subsea compartments such as early diagenesis, subsea permafrost, methane hydrates, and underlying thermogenic/ free gas to these methane releases remain elusive. Dissolved methane concentrations observed in the Laptev Sea ranged from 3 to 1,500 nM (median 151 nM; oversaturation by similar to 3,800%). Methane stable isotopic composition showed strong vertical and horizontal gradients with source signatures for two seepage areas of delta C-13-CH4 = (-42.6 +/- 0.5)/(-55.0 +/- 0.5) % and delta D-CH4 = (-136.8 +/- 8.0)/(-158.1 +/- 5.5) %, suggesting a thermogenic/ natural gas source. Increasingly enriched delta C-13-CH4 and delta D-CH4 at distance from the seeps indicated methane oxidation. The Delta C-14-CH4 signal was strongly depleted (i.e., old) near the seeps (-993 +/- 19/-1050 +/- 89%). Hence, all three isotope systems are consistent with methane release from an old, deep, and likely thermogenic pool to the outer Laptev Sea. This knowledge of what subsea sources are contributing to the observed methane release is a prerequisite to predictions on how these emissions will increase over coming decades and centuries.
Subject headings
- NATURVETENSKAP -- Geovetenskap och miljövetenskap (hsv//swe)
- NATURAL SCIENCES -- Earth and Related Environmental Sciences (hsv//eng)
- NATURVETENSKAP -- Biologi (hsv//swe)
- NATURAL SCIENCES -- Biological Sciences (hsv//eng)
Keyword
- methane
- isotopes/radiocarbon
- Arctic
- carbon cycle/climate change
- subsea permafrost
Publication and Content Type
- ref (subject category)
- art (subject category)
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- By the author/editor
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Steinbach, Julia
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Holmstrand, Henr ...
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Shcherbakova, Ks ...
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Kosmach, Denis
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Brüchert, Volker
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Shakhova, Natali ...
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show more...
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Salyuk, Anatoly
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Sapart, Celia J.
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Chernykh, Denis
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Noormets, Riko
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Semiletov, Igor
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Gustafsson, Örja ...
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show less...
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- NATURAL SCIENCES
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NATURAL SCIENCES
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and Earth and Relate ...
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- NATURAL SCIENCES
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NATURAL SCIENCES
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and Biological Scien ...
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Proceedings of t ...
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Stockholm University