A water column study of methane around gas flares located at the West Spitsbergen continental margin
Abstract In the Arctic Seas, the West Spitsbergen continental margin represents a prominent methane seep area. In this area, free gas formation and gas ebullition as a consequence of hydrate dissociation due to global warming are currently under debate. Recent studies revealed shallow gas accumulati...
Published in: | Continental Shelf Research |
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PERGAMON-ELSEVIER SCIENCE LTD
2014
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Online Access: | https://epic.awi.de/id/eprint/33989/ https://epic.awi.de/id/eprint/33989/1/TGentz_et_al_2013.pdf http://www.sciencedirect.com/science/article/pii/S0278434313002604 https://hdl.handle.net/10013/epic.42490 https://hdl.handle.net/10013/epic.42490.d001 |
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ftawi:oai:epic.awi.de:33989 2024-09-09T19:28:31+00:00 A water column study of methane around gas flares located at the West Spitsbergen continental margin Gentz, Torben Damm, Ellen von Deimling, Jens Schneider Mau, Susan McGinnis, Daniel Frank Schlüter, Michael 2014 application/pdf https://epic.awi.de/id/eprint/33989/ https://epic.awi.de/id/eprint/33989/1/TGentz_et_al_2013.pdf http://www.sciencedirect.com/science/article/pii/S0278434313002604 https://hdl.handle.net/10013/epic.42490 https://hdl.handle.net/10013/epic.42490.d001 unknown PERGAMON-ELSEVIER SCIENCE LTD https://epic.awi.de/id/eprint/33989/1/TGentz_et_al_2013.pdf https://hdl.handle.net/10013/epic.42490.d001 Gentz, T. orcid:0000-0001-6739-5359 , Damm, E. orcid:0000-0002-1487-1283 , von Deimling, J. S. , Mau, S. , McGinnis, D. F. and Schlüter, M. orcid:0000-0002-4997-3802 (2014) A water column study of methane around gas flares located at the West Spitsbergen continental margin , Continental Shelf Research, 72 , 107- 118 . doi:10.1016/j.csr.2013.07.013 <https://doi.org/10.1016/j.csr.2013.07.013> , hdl:10013/epic.42490 EPIC3Continental Shelf Research, PERGAMON-ELSEVIER SCIENCE LTD, 72, pp. 107- 118, ISSN: 0278-4343 Article isiRev 2014 ftawi https://doi.org/10.1016/j.csr.2013.07.013 2024-06-24T04:07:26Z Abstract In the Arctic Seas, the West Spitsbergen continental margin represents a prominent methane seep area. In this area, free gas formation and gas ebullition as a consequence of hydrate dissociation due to global warming are currently under debate. Recent studies revealed shallow gas accumulation and ebullition of methane into the water column at more than 250 sites in an area of 665 km2. We conducted a detailed study of a subregion of this area, which covers an active gas ebullition area of 175 km2 characterized by 10 gas flares reaching from the seafloor at~245 m up to 50 m water depth to identify the fate of the released gas due to dissolution of methane from gas bubbles and subsequent mixing, transport and microbial oxidation. The oceanographic data indicated a salinity-controlled pycnocline situated ~20 m above the seafloor. A high resolution sampling program at the pycnocline at the active gas ebullition flare area revealed that the methane concentration gradient is strongly controlled by the pycnocline. While high methane concentrations of up to 524 nmol L−1 were measured below the pycnocline, low methane concentrations of less than 20 nmol L−1 were observed in the water column above. Variations in the δ 13 C CH 4 values point to a 13C depleted methane source (~−60‰ VPDB) being mainly mixed with a background values of the ambient water (~−37.5‰ VPDB). A gas bubble dissolution model indicates that ~80% of the methane released from gas bubbles into the ambient water takes place below the pycnocline. This dissolved methane will be laterally transported with the current northwards and most likely microbially oxidized in between 50 and 100 days, since microbial CH4 oxidation rates of 0.78 nmol d−1 were measured. Above the pycnocline, methane concentrations decrease to local background concentration of ~10 nmol L−1. Our results suggest that the methane dissolved from gas bubbles is efficiently trapped below the pycnocline and thus limits the methane concentration in surface water and the air–sea exchange ... Article in Journal/Newspaper Arctic Global warming Spitsbergen Alfred Wegener Institute for Polar- and Marine Research (AWI): ePIC (electronic Publication Information Center) Arctic Continental Shelf Research 72 107 118 |
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Open Polar |
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Alfred Wegener Institute for Polar- and Marine Research (AWI): ePIC (electronic Publication Information Center) |
op_collection_id |
ftawi |
language |
unknown |
description |
Abstract In the Arctic Seas, the West Spitsbergen continental margin represents a prominent methane seep area. In this area, free gas formation and gas ebullition as a consequence of hydrate dissociation due to global warming are currently under debate. Recent studies revealed shallow gas accumulation and ebullition of methane into the water column at more than 250 sites in an area of 665 km2. We conducted a detailed study of a subregion of this area, which covers an active gas ebullition area of 175 km2 characterized by 10 gas flares reaching from the seafloor at~245 m up to 50 m water depth to identify the fate of the released gas due to dissolution of methane from gas bubbles and subsequent mixing, transport and microbial oxidation. The oceanographic data indicated a salinity-controlled pycnocline situated ~20 m above the seafloor. A high resolution sampling program at the pycnocline at the active gas ebullition flare area revealed that the methane concentration gradient is strongly controlled by the pycnocline. While high methane concentrations of up to 524 nmol L−1 were measured below the pycnocline, low methane concentrations of less than 20 nmol L−1 were observed in the water column above. Variations in the δ 13 C CH 4 values point to a 13C depleted methane source (~−60‰ VPDB) being mainly mixed with a background values of the ambient water (~−37.5‰ VPDB). A gas bubble dissolution model indicates that ~80% of the methane released from gas bubbles into the ambient water takes place below the pycnocline. This dissolved methane will be laterally transported with the current northwards and most likely microbially oxidized in between 50 and 100 days, since microbial CH4 oxidation rates of 0.78 nmol d−1 were measured. Above the pycnocline, methane concentrations decrease to local background concentration of ~10 nmol L−1. Our results suggest that the methane dissolved from gas bubbles is efficiently trapped below the pycnocline and thus limits the methane concentration in surface water and the air–sea exchange ... |
format |
Article in Journal/Newspaper |
author |
Gentz, Torben Damm, Ellen von Deimling, Jens Schneider Mau, Susan McGinnis, Daniel Frank Schlüter, Michael |
spellingShingle |
Gentz, Torben Damm, Ellen von Deimling, Jens Schneider Mau, Susan McGinnis, Daniel Frank Schlüter, Michael A water column study of methane around gas flares located at the West Spitsbergen continental margin |
author_facet |
Gentz, Torben Damm, Ellen von Deimling, Jens Schneider Mau, Susan McGinnis, Daniel Frank Schlüter, Michael |
author_sort |
Gentz, Torben |
title |
A water column study of methane around gas flares located at the West Spitsbergen continental margin |
title_short |
A water column study of methane around gas flares located at the West Spitsbergen continental margin |
title_full |
A water column study of methane around gas flares located at the West Spitsbergen continental margin |
title_fullStr |
A water column study of methane around gas flares located at the West Spitsbergen continental margin |
title_full_unstemmed |
A water column study of methane around gas flares located at the West Spitsbergen continental margin |
title_sort |
water column study of methane around gas flares located at the west spitsbergen continental margin |
publisher |
PERGAMON-ELSEVIER SCIENCE LTD |
publishDate |
2014 |
url |
https://epic.awi.de/id/eprint/33989/ https://epic.awi.de/id/eprint/33989/1/TGentz_et_al_2013.pdf http://www.sciencedirect.com/science/article/pii/S0278434313002604 https://hdl.handle.net/10013/epic.42490 https://hdl.handle.net/10013/epic.42490.d001 |
geographic |
Arctic |
geographic_facet |
Arctic |
genre |
Arctic Global warming Spitsbergen |
genre_facet |
Arctic Global warming Spitsbergen |
op_source |
EPIC3Continental Shelf Research, PERGAMON-ELSEVIER SCIENCE LTD, 72, pp. 107- 118, ISSN: 0278-4343 |
op_relation |
https://epic.awi.de/id/eprint/33989/1/TGentz_et_al_2013.pdf https://hdl.handle.net/10013/epic.42490.d001 Gentz, T. orcid:0000-0001-6739-5359 , Damm, E. orcid:0000-0002-1487-1283 , von Deimling, J. S. , Mau, S. , McGinnis, D. F. and Schlüter, M. orcid:0000-0002-4997-3802 (2014) A water column study of methane around gas flares located at the West Spitsbergen continental margin , Continental Shelf Research, 72 , 107- 118 . doi:10.1016/j.csr.2013.07.013 <https://doi.org/10.1016/j.csr.2013.07.013> , hdl:10013/epic.42490 |
op_doi |
https://doi.org/10.1016/j.csr.2013.07.013 |
container_title |
Continental Shelf Research |
container_volume |
72 |
container_start_page |
107 |
op_container_end_page |
118 |
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1809897842711461888 |