Biogeochemistry of a low-activity cold seep in the Larsen B area, western Weddell Sea, Antarctica
First videographic indication of an Antarctic cold seep ecosystem was recently obtained from the collapsed Larsen B ice shelf, western Weddell Sea (Domack et al., 2005). Within the framework of the R/V Polarstern expedition ANTXXIII-8, we revisited this area for geochemical, microbiological and furt...
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ftcopernicus:oai:publications.copernicus.org:bg1065 2023-05-15T13:45:55+02:00 Biogeochemistry of a low-activity cold seep in the Larsen B area, western Weddell Sea, Antarctica Niemann, H. Fischer, D. Graffe, D. Knittel, K. Montiel, A. Heilmayer, O. Nöthen, K. Pape, T. Kasten, S. Bohrmann, G. Boetius, A. Gutt, J. 2018-09-27 application/pdf https://doi.org/10.5194/bg-6-2383-2009 https://www.biogeosciences.net/6/2383/2009/ eng eng doi:10.5194/bg-6-2383-2009 https://www.biogeosciences.net/6/2383/2009/ eISSN: 1726-4189 Text 2018 ftcopernicus https://doi.org/10.5194/bg-6-2383-2009 2019-12-24T09:57:39Z First videographic indication of an Antarctic cold seep ecosystem was recently obtained from the collapsed Larsen B ice shelf, western Weddell Sea (Domack et al., 2005). Within the framework of the R/V Polarstern expedition ANTXXIII-8, we revisited this area for geochemical, microbiological and further videographical examinations. During two dives with ROV Cherokee (MARUM, Bremen), several bivalve shell agglomerations of the seep-associated, chemosynthetic clam Calyptogena sp. were found in the trough of the Crane and Evans glacier. The absence of living clam specimens indicates that the flux of sulphide and hence the seepage activity is diminished at present. This impression was further substantiated by our geochemical observations. Concentrations of thermogenic methane were moderately elevated with 2 μM in surface sediments of a clam patch, increasing up to 9 μM at a sediment depth of about 1 m in the bottom sections of the sediment cores. This correlated with a moderate decrease in sulphate from about 28 mM at the surface down to 23.4 mM, an increase in sulphide to up to 1.43 mM and elevated rates of the anaerobic oxidation of methane (AOM) of up to 600 pmol cm −3 d −1 at about 1 m below the seafloor. Molecular analyses indicate that methanotrophic archaea related to ANME-3 are the most likely candidates mediating AOM in sediments of the Larsen B seep. Text Antarc* Antarctic Antarctica Ice Shelf Weddell Sea Copernicus Publications: E-Journals Antarctic Weddell Weddell Sea Biogeosciences 6 11 2383 2395 |
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Open Polar |
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Copernicus Publications: E-Journals |
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ftcopernicus |
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English |
description |
First videographic indication of an Antarctic cold seep ecosystem was recently obtained from the collapsed Larsen B ice shelf, western Weddell Sea (Domack et al., 2005). Within the framework of the R/V Polarstern expedition ANTXXIII-8, we revisited this area for geochemical, microbiological and further videographical examinations. During two dives with ROV Cherokee (MARUM, Bremen), several bivalve shell agglomerations of the seep-associated, chemosynthetic clam Calyptogena sp. were found in the trough of the Crane and Evans glacier. The absence of living clam specimens indicates that the flux of sulphide and hence the seepage activity is diminished at present. This impression was further substantiated by our geochemical observations. Concentrations of thermogenic methane were moderately elevated with 2 μM in surface sediments of a clam patch, increasing up to 9 μM at a sediment depth of about 1 m in the bottom sections of the sediment cores. This correlated with a moderate decrease in sulphate from about 28 mM at the surface down to 23.4 mM, an increase in sulphide to up to 1.43 mM and elevated rates of the anaerobic oxidation of methane (AOM) of up to 600 pmol cm −3 d −1 at about 1 m below the seafloor. Molecular analyses indicate that methanotrophic archaea related to ANME-3 are the most likely candidates mediating AOM in sediments of the Larsen B seep. |
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Text |
author |
Niemann, H. Fischer, D. Graffe, D. Knittel, K. Montiel, A. Heilmayer, O. Nöthen, K. Pape, T. Kasten, S. Bohrmann, G. Boetius, A. Gutt, J. |
spellingShingle |
Niemann, H. Fischer, D. Graffe, D. Knittel, K. Montiel, A. Heilmayer, O. Nöthen, K. Pape, T. Kasten, S. Bohrmann, G. Boetius, A. Gutt, J. Biogeochemistry of a low-activity cold seep in the Larsen B area, western Weddell Sea, Antarctica |
author_facet |
Niemann, H. Fischer, D. Graffe, D. Knittel, K. Montiel, A. Heilmayer, O. Nöthen, K. Pape, T. Kasten, S. Bohrmann, G. Boetius, A. Gutt, J. |
author_sort |
Niemann, H. |
title |
Biogeochemistry of a low-activity cold seep in the Larsen B area, western Weddell Sea, Antarctica |
title_short |
Biogeochemistry of a low-activity cold seep in the Larsen B area, western Weddell Sea, Antarctica |
title_full |
Biogeochemistry of a low-activity cold seep in the Larsen B area, western Weddell Sea, Antarctica |
title_fullStr |
Biogeochemistry of a low-activity cold seep in the Larsen B area, western Weddell Sea, Antarctica |
title_full_unstemmed |
Biogeochemistry of a low-activity cold seep in the Larsen B area, western Weddell Sea, Antarctica |
title_sort |
biogeochemistry of a low-activity cold seep in the larsen b area, western weddell sea, antarctica |
publishDate |
2018 |
url |
https://doi.org/10.5194/bg-6-2383-2009 https://www.biogeosciences.net/6/2383/2009/ |
geographic |
Antarctic Weddell Weddell Sea |
geographic_facet |
Antarctic Weddell Weddell Sea |
genre |
Antarc* Antarctic Antarctica Ice Shelf Weddell Sea |
genre_facet |
Antarc* Antarctic Antarctica Ice Shelf Weddell Sea |
op_source |
eISSN: 1726-4189 |
op_relation |
doi:10.5194/bg-6-2383-2009 https://www.biogeosciences.net/6/2383/2009/ |
op_doi |
https://doi.org/10.5194/bg-6-2383-2009 |
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Biogeosciences |
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6 |
container_issue |
11 |
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2383 |
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2395 |
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1766232625903566848 |