Autonomous methane seep site monitoring offshore Western Svalbard: Hourly to seasonal variability and associated oceanographic parameters
Improved quantification techniques of natural sources is needed to explain variations in atmospheric methane. In polar regions, high uncertainties in current estimates of methane release from the seabed remain. We present two unique 10 and 3 months long time-series of bottom water measurements of ph...
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Copernicus Publications (EGU)
2022
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Online Access: | https://oceanrep.geomar.de/id/eprint/54779/ https://oceanrep.geomar.de/id/eprint/54779/7/os-18-233-2022.pdf https://doi.org/10.5194/os-18-233-2022 |
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ftoceanrep:oai:oceanrep.geomar.de:54779 2024-02-11T10:09:02+01:00 Autonomous methane seep site monitoring offshore Western Svalbard: Hourly to seasonal variability and associated oceanographic parameters Dølven, Knut Ola Ferré, Bénédicte Silyakova, Anna Jansson, Pär Linke, Peter Moser, Manuel 2022-02-18 text https://oceanrep.geomar.de/id/eprint/54779/ https://oceanrep.geomar.de/id/eprint/54779/7/os-18-233-2022.pdf https://doi.org/10.5194/os-18-233-2022 en eng Copernicus Publications (EGU) https://oceanrep.geomar.de/id/eprint/54779/7/os-18-233-2022.pdf Dølven, K. O., Ferré, B., Silyakova, A., Jansson, P., Linke, P. and Moser, M. (2022) Autonomous methane seep site monitoring offshore Western Svalbard: Hourly to seasonal variability and associated oceanographic parameters. Open Access Ocean Science, 18 . pp. 233-254. DOI 10.5194/os-18-233-2022 <https://doi.org/10.5194/os-18-233-2022>. doi:10.5194/os-18-233-2022 cc_by_4.0 info:eu-repo/semantics/openAccess Article PeerReviewed 2022 ftoceanrep https://doi.org/10.5194/os-18-233-2022 2024-01-15T00:24:50Z Improved quantification techniques of natural sources is needed to explain variations in atmospheric methane. In polar regions, high uncertainties in current estimates of methane release from the seabed remain. We present two unique 10 and 3 months long time-series of bottom water measurements of physical and chemical parameters from two autonomous ocean observatories deployed at separate intense seabed methane seep sites (91 and 246 m depth) offshore Western Svalbard from 2015 to 2016. Results show high short term (100–1000 nmol L-1 within hours) and seasonal variation, as well as higher (2–7 times) methane concentrations compared to previous measurements. Rapid variability is explained by uneven distribution of seepage and changing ocean current directions. No overt influence of tidal hydrostatic pressure or water temperature variations on methane concentration was observed, but an observed negative correlation with temperature at the 246 site fits with hypothesized seasonal blocking of lateral methane pathways in the sediments. Negative correlation between bottom water methane concentration/variability and wind forcing, concomitant with signs of weaker water column stratification, indicates increased potential for methane release to the atmosphere in fall/winter. We highlight uncertainties in methane inventory estimates based on discrete water sampling and present new information about short- and long-term methane variability which can help constrain future estimates of seabed methane seepage. Article in Journal/Newspaper Svalbard OceanRep (GEOMAR Helmholtz Centre für Ocean Research Kiel) Svalbard Ocean Science 18 1 233 254 |
institution |
Open Polar |
collection |
OceanRep (GEOMAR Helmholtz Centre für Ocean Research Kiel) |
op_collection_id |
ftoceanrep |
language |
English |
description |
Improved quantification techniques of natural sources is needed to explain variations in atmospheric methane. In polar regions, high uncertainties in current estimates of methane release from the seabed remain. We present two unique 10 and 3 months long time-series of bottom water measurements of physical and chemical parameters from two autonomous ocean observatories deployed at separate intense seabed methane seep sites (91 and 246 m depth) offshore Western Svalbard from 2015 to 2016. Results show high short term (100–1000 nmol L-1 within hours) and seasonal variation, as well as higher (2–7 times) methane concentrations compared to previous measurements. Rapid variability is explained by uneven distribution of seepage and changing ocean current directions. No overt influence of tidal hydrostatic pressure or water temperature variations on methane concentration was observed, but an observed negative correlation with temperature at the 246 site fits with hypothesized seasonal blocking of lateral methane pathways in the sediments. Negative correlation between bottom water methane concentration/variability and wind forcing, concomitant with signs of weaker water column stratification, indicates increased potential for methane release to the atmosphere in fall/winter. We highlight uncertainties in methane inventory estimates based on discrete water sampling and present new information about short- and long-term methane variability which can help constrain future estimates of seabed methane seepage. |
format |
Article in Journal/Newspaper |
author |
Dølven, Knut Ola Ferré, Bénédicte Silyakova, Anna Jansson, Pär Linke, Peter Moser, Manuel |
spellingShingle |
Dølven, Knut Ola Ferré, Bénédicte Silyakova, Anna Jansson, Pär Linke, Peter Moser, Manuel Autonomous methane seep site monitoring offshore Western Svalbard: Hourly to seasonal variability and associated oceanographic parameters |
author_facet |
Dølven, Knut Ola Ferré, Bénédicte Silyakova, Anna Jansson, Pär Linke, Peter Moser, Manuel |
author_sort |
Dølven, Knut Ola |
title |
Autonomous methane seep site monitoring offshore Western Svalbard: Hourly to seasonal variability and associated oceanographic parameters |
title_short |
Autonomous methane seep site monitoring offshore Western Svalbard: Hourly to seasonal variability and associated oceanographic parameters |
title_full |
Autonomous methane seep site monitoring offshore Western Svalbard: Hourly to seasonal variability and associated oceanographic parameters |
title_fullStr |
Autonomous methane seep site monitoring offshore Western Svalbard: Hourly to seasonal variability and associated oceanographic parameters |
title_full_unstemmed |
Autonomous methane seep site monitoring offshore Western Svalbard: Hourly to seasonal variability and associated oceanographic parameters |
title_sort |
autonomous methane seep site monitoring offshore western svalbard: hourly to seasonal variability and associated oceanographic parameters |
publisher |
Copernicus Publications (EGU) |
publishDate |
2022 |
url |
https://oceanrep.geomar.de/id/eprint/54779/ https://oceanrep.geomar.de/id/eprint/54779/7/os-18-233-2022.pdf https://doi.org/10.5194/os-18-233-2022 |
geographic |
Svalbard |
geographic_facet |
Svalbard |
genre |
Svalbard |
genre_facet |
Svalbard |
op_relation |
https://oceanrep.geomar.de/id/eprint/54779/7/os-18-233-2022.pdf Dølven, K. O., Ferré, B., Silyakova, A., Jansson, P., Linke, P. and Moser, M. (2022) Autonomous methane seep site monitoring offshore Western Svalbard: Hourly to seasonal variability and associated oceanographic parameters. Open Access Ocean Science, 18 . pp. 233-254. DOI 10.5194/os-18-233-2022 <https://doi.org/10.5194/os-18-233-2022>. doi:10.5194/os-18-233-2022 |
op_rights |
cc_by_4.0 info:eu-repo/semantics/openAccess |
op_doi |
https://doi.org/10.5194/os-18-233-2022 |
container_title |
Ocean Science |
container_volume |
18 |
container_issue |
1 |
container_start_page |
233 |
op_container_end_page |
254 |
_version_ |
1790608738953986048 |