Autonomous methane seep site monitoring offshore western Svalbard: hourly to seasonal variability and associated oceanographic parameters
Improved quantification techniques of natural sources are needed to explain variations in atmospheric methane. In polar regions, high uncertainties in current estimates of methane release from the seabed remain. We present unique 10- and 3-month time series of bottom water measurements of physical a...
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2022
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Online Access: | https://doi.org/10.5194/os-18-233-2022 https://doaj.org/article/ab15a43c387648e1bbfa4a92ff693d8f |
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ftdoajarticles:oai:doaj.org/article:ab15a43c387648e1bbfa4a92ff693d8f 2023-05-15T18:29:44+02:00 Autonomous methane seep site monitoring offshore western Svalbard: hourly to seasonal variability and associated oceanographic parameters K. O. Dølven B. Ferré A. Silyakova P. Jansson P. Linke M. Moser 2022-02-01T00:00:00Z https://doi.org/10.5194/os-18-233-2022 https://doaj.org/article/ab15a43c387648e1bbfa4a92ff693d8f EN eng Copernicus Publications https://os.copernicus.org/articles/18/233/2022/os-18-233-2022.pdf https://doaj.org/toc/1812-0784 https://doaj.org/toc/1812-0792 doi:10.5194/os-18-233-2022 1812-0784 1812-0792 https://doaj.org/article/ab15a43c387648e1bbfa4a92ff693d8f Ocean Science, Vol 18, Pp 233-254 (2022) Geography. Anthropology. Recreation G Environmental sciences GE1-350 article 2022 ftdoajarticles https://doi.org/10.5194/os-18-233-2022 2022-12-31T07:13:09Z Improved quantification techniques of natural sources are needed to explain variations in atmospheric methane. In polar regions, high uncertainties in current estimates of methane release from the seabed remain. We present unique 10- and 3-month 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 m site fits with hypothesized seasonal blocking of lateral methane pathways in the sediments. Negative correlation between bottom water methane concentration (and variability) and wind forcing, concomitant with signs of weaker water column stratification, indicates increased potential for methane release to the atmosphere in fall and winter. We present new information about short- and long-term methane variability and provide a preliminary constraint on the uncertainties that arise in methane inventory estimates from this variability. Article in Journal/Newspaper Svalbard Directory of Open Access Journals: DOAJ Articles Svalbard Ocean Science 18 1 233 254 |
institution |
Open Polar |
collection |
Directory of Open Access Journals: DOAJ Articles |
op_collection_id |
ftdoajarticles |
language |
English |
topic |
Geography. Anthropology. Recreation G Environmental sciences GE1-350 |
spellingShingle |
Geography. Anthropology. Recreation G Environmental sciences GE1-350 K. O. Dølven B. Ferré A. Silyakova P. Jansson P. Linke M. Moser Autonomous methane seep site monitoring offshore western Svalbard: hourly to seasonal variability and associated oceanographic parameters |
topic_facet |
Geography. Anthropology. Recreation G Environmental sciences GE1-350 |
description |
Improved quantification techniques of natural sources are needed to explain variations in atmospheric methane. In polar regions, high uncertainties in current estimates of methane release from the seabed remain. We present unique 10- and 3-month 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 m site fits with hypothesized seasonal blocking of lateral methane pathways in the sediments. Negative correlation between bottom water methane concentration (and variability) and wind forcing, concomitant with signs of weaker water column stratification, indicates increased potential for methane release to the atmosphere in fall and winter. We present new information about short- and long-term methane variability and provide a preliminary constraint on the uncertainties that arise in methane inventory estimates from this variability. |
format |
Article in Journal/Newspaper |
author |
K. O. Dølven B. Ferré A. Silyakova P. Jansson P. Linke M. Moser |
author_facet |
K. O. Dølven B. Ferré A. Silyakova P. Jansson P. Linke M. Moser |
author_sort |
K. O. Dølven |
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 |
publishDate |
2022 |
url |
https://doi.org/10.5194/os-18-233-2022 https://doaj.org/article/ab15a43c387648e1bbfa4a92ff693d8f |
geographic |
Svalbard |
geographic_facet |
Svalbard |
genre |
Svalbard |
genre_facet |
Svalbard |
op_source |
Ocean Science, Vol 18, Pp 233-254 (2022) |
op_relation |
https://os.copernicus.org/articles/18/233/2022/os-18-233-2022.pdf https://doaj.org/toc/1812-0784 https://doaj.org/toc/1812-0792 doi:10.5194/os-18-233-2022 1812-0784 1812-0792 https://doaj.org/article/ab15a43c387648e1bbfa4a92ff693d8f |
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_ |
1766213066717921280 |