Physical oceanography during POLARSTERN cruise ANT-XXIX/4
Recent studies have suggested that the marine contribution of methane from shallow regions and melting marine terminating glaciers may have been underestimated. Here we report on methane sources and potential sinks associated with methane seeps in Cumberland Bay, South Georgia's largest fjord s...
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Format: | Dataset |
Language: | English |
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PANGAEA
2016
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Online Access: | https://doi.pangaea.de/10.1594/PANGAEA.857302 https://doi.org/10.1594/PANGAEA.857302 |
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ftpangaea:oai:pangaea.de:doi:10.1594/PANGAEA.857302 |
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record_format |
openpolar |
institution |
Open Polar |
collection |
PANGAEA - Data Publisher for Earth & Environmental Science |
op_collection_id |
ftpangaea |
language |
English |
topic |
Altimeter ANT-XXIX/4 Attenuation optical beam transmission Calculated Computed Conductivity CTD SEA-BIRD SBE 911plus CTD/Rosette CTD-RO Date/Time of event Density sigma-theta (0) DEPTH water Elevation of event Event label Fluorescence chlorophyll Fluorometer WET Labs ECO AFL/FL Height above sea floor/altitude Latitude of event Longitude of event Oxygen Oxygen sensor SBE 43 Polarstern Pressure PS81 PS81/281-1 PS81/282-1 PS81/284-3 PS81/286-1 Salinity Sample ID South Atlantic Ocean Temperature potential Transmissiometer WET Labs C-Star |
spellingShingle |
Altimeter ANT-XXIX/4 Attenuation optical beam transmission Calculated Computed Conductivity CTD SEA-BIRD SBE 911plus CTD/Rosette CTD-RO Date/Time of event Density sigma-theta (0) DEPTH water Elevation of event Event label Fluorescence chlorophyll Fluorometer WET Labs ECO AFL/FL Height above sea floor/altitude Latitude of event Longitude of event Oxygen Oxygen sensor SBE 43 Polarstern Pressure PS81 PS81/281-1 PS81/282-1 PS81/284-3 PS81/286-1 Salinity Sample ID South Atlantic Ocean Temperature potential Transmissiometer WET Labs C-Star Geprägs, Patrizia Torres, Marta E Mau, Susan Kasten, Sabine Römer, Miriam Bohrmann, Gerhard Physical oceanography during POLARSTERN cruise ANT-XXIX/4 |
topic_facet |
Altimeter ANT-XXIX/4 Attenuation optical beam transmission Calculated Computed Conductivity CTD SEA-BIRD SBE 911plus CTD/Rosette CTD-RO Date/Time of event Density sigma-theta (0) DEPTH water Elevation of event Event label Fluorescence chlorophyll Fluorometer WET Labs ECO AFL/FL Height above sea floor/altitude Latitude of event Longitude of event Oxygen Oxygen sensor SBE 43 Polarstern Pressure PS81 PS81/281-1 PS81/282-1 PS81/284-3 PS81/286-1 Salinity Sample ID South Atlantic Ocean Temperature potential Transmissiometer WET Labs C-Star |
description |
Recent studies have suggested that the marine contribution of methane from shallow regions and melting marine terminating glaciers may have been underestimated. Here we report on methane sources and potential sinks associated with methane seeps in Cumberland Bay, South Georgia's largest fjord system. The average organic carbon content in the upper 8 meters of the sediment is around 0.65 wt.%; this observation combined with Parasound data suggest that the methane gas accumulations probably originate from peat-bearing sediments currently located several tens of meters below the seafloor. Only one of our cores indicates upward advection; instead most of the methane is transported via diffusion. Sulfate and methane flux estimates indicate that a large fraction of methane is consumed by anaerobic oxidation of methane (AOM). Carbon cycling at the sulfate-methane transition (SMT) results in a marked fractionation of the d13C-CH4 from an estimated source value of -65 per mil to a value as low as -96 per mil just below the SMT. Methane concentrations in sediments are high, especially close to the seepage sites (~40 mM); however, concentrations in the water column are relatively low (max. 58 nM) and can be observed only close to the seafloor. Methane is trapped in the lowermost water mass, however, measured microbial oxidation rates reveal very low activity with an average turnover of 3.1 years. We therefore infer that methane must be transported out of the bay in the bottom water layer. A mean sea-air flux of only 0.005 nM/m²s confirms that almost no methane reaches the atmosphere. |
format |
Dataset |
author |
Geprägs, Patrizia Torres, Marta E Mau, Susan Kasten, Sabine Römer, Miriam Bohrmann, Gerhard |
author_facet |
Geprägs, Patrizia Torres, Marta E Mau, Susan Kasten, Sabine Römer, Miriam Bohrmann, Gerhard |
author_sort |
Geprägs, Patrizia |
title |
Physical oceanography during POLARSTERN cruise ANT-XXIX/4 |
title_short |
Physical oceanography during POLARSTERN cruise ANT-XXIX/4 |
title_full |
Physical oceanography during POLARSTERN cruise ANT-XXIX/4 |
title_fullStr |
Physical oceanography during POLARSTERN cruise ANT-XXIX/4 |
title_full_unstemmed |
Physical oceanography during POLARSTERN cruise ANT-XXIX/4 |
title_sort |
physical oceanography during polarstern cruise ant-xxix/4 |
publisher |
PANGAEA |
publishDate |
2016 |
url |
https://doi.pangaea.de/10.1594/PANGAEA.857302 https://doi.org/10.1594/PANGAEA.857302 |
op_coverage |
MEDIAN LATITUDE: -54.245875 * MEDIAN LONGITUDE: -36.407500 * SOUTH-BOUND LATITUDE: -54.365330 * WEST-BOUND LONGITUDE: -36.453830 * NORTH-BOUND LATITUDE: -54.150500 * EAST-BOUND LONGITUDE: -36.365830 * DATE/TIME START: 2013-04-11T00:09:00 * DATE/TIME END: 2013-04-12T19:18:00 * MINIMUM DEPTH, water: 2.97 m * MAXIMUM DEPTH, water: 263.45 m |
long_lat |
ENVELOPE(69.052,69.052,-48.781,-48.781) ENVELOPE(-36.453830,-36.365830,-54.150500,-54.365330) |
geographic |
Cumberland Bay |
geographic_facet |
Cumberland Bay |
genre |
South Atlantic Ocean |
genre_facet |
South Atlantic Ocean |
op_relation |
https://doi.org/10.1594/PANGAEA.858963 Geprägs, Patrizia; Torres, Marta E; Mau, Susan; Kasten, Sabine; Römer, Miriam; Bohrmann, Gerhard (2016): Carbon cycling fed by methane seepage at the shallow Cumberland Bay, South Georgia, sub-Antarctic. Geochemistry, Geophysics, Geosystems, 17(4), 1401-1418, https://doi.org/10.1002/2016GC006276 Römer, Miriam; Torres, Marta E; Kasten, Sabine; Kuhn, Gerhard; Graham, Alastair G C; Mau, Susan; Little, Crispin T S; Linse, Katrin; Pape, Thomas; Geprägs, Patrizia; Fischer, David; Wintersteller, Paul; Marcon, Yann; Rethemeyer, Janet; Bohrmann, Gerhard; Shipboard scientific party ANT-XXIX/4 (2014): First evidence of widespread active methane seepage in the Southern Ocean, off the sub-Antarctic island of South Georgia. Earth and Planetary Science Letters, 403, 166-177, https://doi.org/10.1016/j.epsl.2014.06.036 https://doi.pangaea.de/10.1594/PANGAEA.857302 https://doi.org/10.1594/PANGAEA.857302 |
op_rights |
CC-BY-3.0: Creative Commons Attribution 3.0 Unported Access constraints: unrestricted info:eu-repo/semantics/openAccess |
op_rightsnorm |
CC-BY |
op_doi |
https://doi.org/10.1594/PANGAEA.857302 https://doi.org/10.1594/PANGAEA.858963 https://doi.org/10.1002/2016GC006276 https://doi.org/10.1016/j.epsl.2014.06.036 |
_version_ |
1766200577614675968 |
spelling |
ftpangaea:oai:pangaea.de:doi:10.1594/PANGAEA.857302 2023-05-15T18:21:21+02:00 Physical oceanography during POLARSTERN cruise ANT-XXIX/4 Geprägs, Patrizia Torres, Marta E Mau, Susan Kasten, Sabine Römer, Miriam Bohrmann, Gerhard MEDIAN LATITUDE: -54.245875 * MEDIAN LONGITUDE: -36.407500 * SOUTH-BOUND LATITUDE: -54.365330 * WEST-BOUND LONGITUDE: -36.453830 * NORTH-BOUND LATITUDE: -54.150500 * EAST-BOUND LONGITUDE: -36.365830 * DATE/TIME START: 2013-04-11T00:09:00 * DATE/TIME END: 2013-04-12T19:18:00 * MINIMUM DEPTH, water: 2.97 m * MAXIMUM DEPTH, water: 263.45 m 2016-01-25 text/tab-separated-values, 8881 data points https://doi.pangaea.de/10.1594/PANGAEA.857302 https://doi.org/10.1594/PANGAEA.857302 en eng PANGAEA https://doi.org/10.1594/PANGAEA.858963 Geprägs, Patrizia; Torres, Marta E; Mau, Susan; Kasten, Sabine; Römer, Miriam; Bohrmann, Gerhard (2016): Carbon cycling fed by methane seepage at the shallow Cumberland Bay, South Georgia, sub-Antarctic. Geochemistry, Geophysics, Geosystems, 17(4), 1401-1418, https://doi.org/10.1002/2016GC006276 Römer, Miriam; Torres, Marta E; Kasten, Sabine; Kuhn, Gerhard; Graham, Alastair G C; Mau, Susan; Little, Crispin T S; Linse, Katrin; Pape, Thomas; Geprägs, Patrizia; Fischer, David; Wintersteller, Paul; Marcon, Yann; Rethemeyer, Janet; Bohrmann, Gerhard; Shipboard scientific party ANT-XXIX/4 (2014): First evidence of widespread active methane seepage in the Southern Ocean, off the sub-Antarctic island of South Georgia. Earth and Planetary Science Letters, 403, 166-177, https://doi.org/10.1016/j.epsl.2014.06.036 https://doi.pangaea.de/10.1594/PANGAEA.857302 https://doi.org/10.1594/PANGAEA.857302 CC-BY-3.0: Creative Commons Attribution 3.0 Unported Access constraints: unrestricted info:eu-repo/semantics/openAccess CC-BY Altimeter ANT-XXIX/4 Attenuation optical beam transmission Calculated Computed Conductivity CTD SEA-BIRD SBE 911plus CTD/Rosette CTD-RO Date/Time of event Density sigma-theta (0) DEPTH water Elevation of event Event label Fluorescence chlorophyll Fluorometer WET Labs ECO AFL/FL Height above sea floor/altitude Latitude of event Longitude of event Oxygen Oxygen sensor SBE 43 Polarstern Pressure PS81 PS81/281-1 PS81/282-1 PS81/284-3 PS81/286-1 Salinity Sample ID South Atlantic Ocean Temperature potential Transmissiometer WET Labs C-Star Dataset 2016 ftpangaea https://doi.org/10.1594/PANGAEA.857302 https://doi.org/10.1594/PANGAEA.858963 https://doi.org/10.1002/2016GC006276 https://doi.org/10.1016/j.epsl.2014.06.036 2023-01-20T09:53:16Z Recent studies have suggested that the marine contribution of methane from shallow regions and melting marine terminating glaciers may have been underestimated. Here we report on methane sources and potential sinks associated with methane seeps in Cumberland Bay, South Georgia's largest fjord system. The average organic carbon content in the upper 8 meters of the sediment is around 0.65 wt.%; this observation combined with Parasound data suggest that the methane gas accumulations probably originate from peat-bearing sediments currently located several tens of meters below the seafloor. Only one of our cores indicates upward advection; instead most of the methane is transported via diffusion. Sulfate and methane flux estimates indicate that a large fraction of methane is consumed by anaerobic oxidation of methane (AOM). Carbon cycling at the sulfate-methane transition (SMT) results in a marked fractionation of the d13C-CH4 from an estimated source value of -65 per mil to a value as low as -96 per mil just below the SMT. Methane concentrations in sediments are high, especially close to the seepage sites (~40 mM); however, concentrations in the water column are relatively low (max. 58 nM) and can be observed only close to the seafloor. Methane is trapped in the lowermost water mass, however, measured microbial oxidation rates reveal very low activity with an average turnover of 3.1 years. We therefore infer that methane must be transported out of the bay in the bottom water layer. A mean sea-air flux of only 0.005 nM/m²s confirms that almost no methane reaches the atmosphere. Dataset South Atlantic Ocean PANGAEA - Data Publisher for Earth & Environmental Science Cumberland Bay ENVELOPE(69.052,69.052,-48.781,-48.781) ENVELOPE(-36.453830,-36.365830,-54.150500,-54.365330) |