The origin of methane in the East Siberian Arctic Shelf unraveled with triple isotope analysis
The Arctic Ocean, especially the East Siberian Arctic Shelf (ESAS), has been proposed as a significant source of methane that might play an increasingly important role in the future. However, the underlying processes of formation, removal and transport associated with such emissions are to date stro...
Published in: | Biogeosciences |
---|---|
Main Authors: | , , , , , , , , , , , , , |
Format: | Text |
Language: | English |
Published: |
2018
|
Subjects: | |
Online Access: | https://doi.org/10.5194/bg-14-2283-2017 https://www.biogeosciences.net/14/2283/2017/ |
id |
ftcopernicus:oai:publications.copernicus.org:bg54537 |
---|---|
record_format |
openpolar |
spelling |
ftcopernicus:oai:publications.copernicus.org:bg54537 2023-05-15T14:53:34+02:00 The origin of methane in the East Siberian Arctic Shelf unraveled with triple isotope analysis Sapart, Célia J. Shakhova, Natalia Semiletov, Igor Jansen, Joachim Szidat, Sönke Kosmach, Denis Dudarev, Oleg Veen, Carina Egger, Matthias Sergienko, Valentine Salyuk, Anatoly Tumskoy, Vladimir Tison, Jean-Louis Röckmann, Thomas 2018-09-27 application/pdf https://doi.org/10.5194/bg-14-2283-2017 https://www.biogeosciences.net/14/2283/2017/ eng eng doi:10.5194/bg-14-2283-2017 https://www.biogeosciences.net/14/2283/2017/ eISSN: 1726-4189 Text 2018 ftcopernicus https://doi.org/10.5194/bg-14-2283-2017 2019-12-24T09:51:28Z The Arctic Ocean, especially the East Siberian Arctic Shelf (ESAS), has been proposed as a significant source of methane that might play an increasingly important role in the future. However, the underlying processes of formation, removal and transport associated with such emissions are to date strongly debated. CH 4 concentration and triple isotope composition were analyzed on gas extracted from sediment and water sampled at numerous locations on the shallow ESAS from 2007 to 2013. We find high concentrations (up to 500 µM) of CH 4 in the pore water of the partially thawed subsea permafrost of this region. For all sediment cores, both hydrogen and carbon isotope data reveal the predominant occurrence of CH 4 that is not of thermogenic origin as it has long been thought, but resultant from microbial CH 4 formation. At some locations, meltwater from buried meteoric ice and/or old organic matter preserved in the subsea permafrost were used as substrates. Radiocarbon data demonstrate that the CH 4 present in the ESAS sediment is of Pleistocene age or older, but a small contribution of highly 14 C-enriched CH 4 , from unknown origin, prohibits precise age determination for one sediment core and in the water column. Our sediment data suggest that at locations where bubble plumes have been observed, CH 4 can escape anaerobic oxidation in the surface sediment. Text Arctic Arctic Ocean Ice permafrost Copernicus Publications: E-Journals Arctic Arctic Ocean Biogeosciences 14 9 2283 2292 |
institution |
Open Polar |
collection |
Copernicus Publications: E-Journals |
op_collection_id |
ftcopernicus |
language |
English |
description |
The Arctic Ocean, especially the East Siberian Arctic Shelf (ESAS), has been proposed as a significant source of methane that might play an increasingly important role in the future. However, the underlying processes of formation, removal and transport associated with such emissions are to date strongly debated. CH 4 concentration and triple isotope composition were analyzed on gas extracted from sediment and water sampled at numerous locations on the shallow ESAS from 2007 to 2013. We find high concentrations (up to 500 µM) of CH 4 in the pore water of the partially thawed subsea permafrost of this region. For all sediment cores, both hydrogen and carbon isotope data reveal the predominant occurrence of CH 4 that is not of thermogenic origin as it has long been thought, but resultant from microbial CH 4 formation. At some locations, meltwater from buried meteoric ice and/or old organic matter preserved in the subsea permafrost were used as substrates. Radiocarbon data demonstrate that the CH 4 present in the ESAS sediment is of Pleistocene age or older, but a small contribution of highly 14 C-enriched CH 4 , from unknown origin, prohibits precise age determination for one sediment core and in the water column. Our sediment data suggest that at locations where bubble plumes have been observed, CH 4 can escape anaerobic oxidation in the surface sediment. |
format |
Text |
author |
Sapart, Célia J. Shakhova, Natalia Semiletov, Igor Jansen, Joachim Szidat, Sönke Kosmach, Denis Dudarev, Oleg Veen, Carina Egger, Matthias Sergienko, Valentine Salyuk, Anatoly Tumskoy, Vladimir Tison, Jean-Louis Röckmann, Thomas |
spellingShingle |
Sapart, Célia J. Shakhova, Natalia Semiletov, Igor Jansen, Joachim Szidat, Sönke Kosmach, Denis Dudarev, Oleg Veen, Carina Egger, Matthias Sergienko, Valentine Salyuk, Anatoly Tumskoy, Vladimir Tison, Jean-Louis Röckmann, Thomas The origin of methane in the East Siberian Arctic Shelf unraveled with triple isotope analysis |
author_facet |
Sapart, Célia J. Shakhova, Natalia Semiletov, Igor Jansen, Joachim Szidat, Sönke Kosmach, Denis Dudarev, Oleg Veen, Carina Egger, Matthias Sergienko, Valentine Salyuk, Anatoly Tumskoy, Vladimir Tison, Jean-Louis Röckmann, Thomas |
author_sort |
Sapart, Célia J. |
title |
The origin of methane in the East Siberian Arctic Shelf unraveled with triple isotope analysis |
title_short |
The origin of methane in the East Siberian Arctic Shelf unraveled with triple isotope analysis |
title_full |
The origin of methane in the East Siberian Arctic Shelf unraveled with triple isotope analysis |
title_fullStr |
The origin of methane in the East Siberian Arctic Shelf unraveled with triple isotope analysis |
title_full_unstemmed |
The origin of methane in the East Siberian Arctic Shelf unraveled with triple isotope analysis |
title_sort |
origin of methane in the east siberian arctic shelf unraveled with triple isotope analysis |
publishDate |
2018 |
url |
https://doi.org/10.5194/bg-14-2283-2017 https://www.biogeosciences.net/14/2283/2017/ |
geographic |
Arctic Arctic Ocean |
geographic_facet |
Arctic Arctic Ocean |
genre |
Arctic Arctic Ocean Ice permafrost |
genre_facet |
Arctic Arctic Ocean Ice permafrost |
op_source |
eISSN: 1726-4189 |
op_relation |
doi:10.5194/bg-14-2283-2017 https://www.biogeosciences.net/14/2283/2017/ |
op_doi |
https://doi.org/10.5194/bg-14-2283-2017 |
container_title |
Biogeosciences |
container_volume |
14 |
container_issue |
9 |
container_start_page |
2283 |
op_container_end_page |
2292 |
_version_ |
1766325174728130560 |