Variability of Acoustically Evidenced Methane Bubble Emissions Offshore Western Svalbard
Large reservoirs of methane present in Arctic marine sediments are susceptible to rapid warming, promoting increasing methane emissions. Gas bubbles in the water column can be detected, and flow rates can be quantified using hydroacoustic survey methods, making it possible to monitor spatiotemporal...
Published in: | Geophysical Research Letters |
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Language: | English |
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Wiley
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Online Access: | https://oceanrep.geomar.de/id/eprint/47780/ https://oceanrep.geomar.de/id/eprint/47780/1/Veloso-Alarc-n_et_al-2019-Geophysical_Research_Letters.pdf https://oceanrep.geomar.de/id/eprint/47780/2/grl59359-sup-0001-2019gl082750-si%281%29.pdf https://oceanrep.geomar.de/id/eprint/47780/3/grl59359-sup-0002-2019gl082750-ds01.xlsx https://doi.org/10.1029/2019GL082750 |
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ftoceanrep:oai:oceanrep.geomar.de:47780 2023-05-15T15:01:51+02:00 Variability of Acoustically Evidenced Methane Bubble Emissions Offshore Western Svalbard Veloso‐Alarcon, Mario E. Jansson, Pär De Batist, Marc Minshull, Timothy A. Westbrook, Graham K. Pälike, Heiko Bünz, Stefan Wright, Ian Greinert, Jens 2019-08-16 text other https://oceanrep.geomar.de/id/eprint/47780/ https://oceanrep.geomar.de/id/eprint/47780/1/Veloso-Alarc-n_et_al-2019-Geophysical_Research_Letters.pdf https://oceanrep.geomar.de/id/eprint/47780/2/grl59359-sup-0001-2019gl082750-si%281%29.pdf https://oceanrep.geomar.de/id/eprint/47780/3/grl59359-sup-0002-2019gl082750-ds01.xlsx https://doi.org/10.1029/2019GL082750 en eng Wiley AGU (American Geophysical Union) https://oceanrep.geomar.de/id/eprint/47780/1/Veloso-Alarc-n_et_al-2019-Geophysical_Research_Letters.pdf https://oceanrep.geomar.de/id/eprint/47780/2/grl59359-sup-0001-2019gl082750-si%281%29.pdf https://oceanrep.geomar.de/id/eprint/47780/3/grl59359-sup-0002-2019gl082750-ds01.xlsx Veloso‐Alarcon, M. E. , Jansson, P. , De Batist, M. , Minshull, T. A. , Westbrook, G. K. , Pälike, H., Bünz, S. , Wright, I. and Greinert, J. (2019) Variability of Acoustically Evidenced Methane Bubble Emissions Offshore Western Svalbard. Open Access Geophysical Research Letters, 46 (15). pp. 9072-9081. DOI 10.1029/2019GL082750 <https://doi.org/10.1029/2019GL082750>. doi:10.1029/2019GL082750 info:eu-repo/semantics/openAccess Article PeerReviewed 2019 ftoceanrep https://doi.org/10.1029/2019GL082750 2023-04-07T15:47:19Z Large reservoirs of methane present in Arctic marine sediments are susceptible to rapid warming, promoting increasing methane emissions. Gas bubbles in the water column can be detected, and flow rates can be quantified using hydroacoustic survey methods, making it possible to monitor spatiotemporal variability. We present methane (CH4) bubble flow rates derived from hydroacoustic data sets acquired during 11 research expeditions to the western Svalbard continental margin (2008-2014). Three seepage areas emit in total 725-1,125 t CH4/year, and bubble fluxes are up to 2 kg.m(-2).year (-1). Bubble fluxes vary between different surveys, but no clear trend can be identified. Flux variability analyses suggest that two areas are geologically interconnected, displaying alternating flow changes. Spatial migration of bubble seepage was observed to follow seasonal changes in the theoretical landward limit of the hydrate stability zone, suggesting that formation/dissociation of shallow hydrates, modulated by bottom water temperatures, influences seafloor bubble release. Plain Language Summary It has been speculated that the release of methane (a potent greenhouse gas) from the seafloor in some Arctic Ocean regions is triggered by warming seawater. Emissions of gas bubbles from the seafloor can be detected by ship-mounted sonars. In 2008, a methane seepage area west of Svalbard was hydroacoustically detected for the first time. This seepage was hypothesized to be caused by dissociation of hydrates (ice-like crystals consisting of methane and water) due to ocean warming. We present an analysis of sonar data from 11 surveys conducted between 2008 and 2014. This study is the first comparison of methane seepage-related hydroacoustic data over such a long period. The hydroacoustic mapping and quantification method allowed us to assess the locations and intensity of gas bubble release, and how these parameters change over time, providing necessary data for numerical flux and climate models. No trend of increasing gas flow was ... Article in Journal/Newspaper Arctic Arctic Ocean Svalbard OceanRep (GEOMAR Helmholtz Centre für Ocean Research Kiel) Arctic Arctic Ocean Svalbard Geophysical Research Letters 46 15 9072 9081 |
institution |
Open Polar |
collection |
OceanRep (GEOMAR Helmholtz Centre für Ocean Research Kiel) |
op_collection_id |
ftoceanrep |
language |
English |
description |
Large reservoirs of methane present in Arctic marine sediments are susceptible to rapid warming, promoting increasing methane emissions. Gas bubbles in the water column can be detected, and flow rates can be quantified using hydroacoustic survey methods, making it possible to monitor spatiotemporal variability. We present methane (CH4) bubble flow rates derived from hydroacoustic data sets acquired during 11 research expeditions to the western Svalbard continental margin (2008-2014). Three seepage areas emit in total 725-1,125 t CH4/year, and bubble fluxes are up to 2 kg.m(-2).year (-1). Bubble fluxes vary between different surveys, but no clear trend can be identified. Flux variability analyses suggest that two areas are geologically interconnected, displaying alternating flow changes. Spatial migration of bubble seepage was observed to follow seasonal changes in the theoretical landward limit of the hydrate stability zone, suggesting that formation/dissociation of shallow hydrates, modulated by bottom water temperatures, influences seafloor bubble release. Plain Language Summary It has been speculated that the release of methane (a potent greenhouse gas) from the seafloor in some Arctic Ocean regions is triggered by warming seawater. Emissions of gas bubbles from the seafloor can be detected by ship-mounted sonars. In 2008, a methane seepage area west of Svalbard was hydroacoustically detected for the first time. This seepage was hypothesized to be caused by dissociation of hydrates (ice-like crystals consisting of methane and water) due to ocean warming. We present an analysis of sonar data from 11 surveys conducted between 2008 and 2014. This study is the first comparison of methane seepage-related hydroacoustic data over such a long period. The hydroacoustic mapping and quantification method allowed us to assess the locations and intensity of gas bubble release, and how these parameters change over time, providing necessary data for numerical flux and climate models. No trend of increasing gas flow was ... |
format |
Article in Journal/Newspaper |
author |
Veloso‐Alarcon, Mario E. Jansson, Pär De Batist, Marc Minshull, Timothy A. Westbrook, Graham K. Pälike, Heiko Bünz, Stefan Wright, Ian Greinert, Jens |
spellingShingle |
Veloso‐Alarcon, Mario E. Jansson, Pär De Batist, Marc Minshull, Timothy A. Westbrook, Graham K. Pälike, Heiko Bünz, Stefan Wright, Ian Greinert, Jens Variability of Acoustically Evidenced Methane Bubble Emissions Offshore Western Svalbard |
author_facet |
Veloso‐Alarcon, Mario E. Jansson, Pär De Batist, Marc Minshull, Timothy A. Westbrook, Graham K. Pälike, Heiko Bünz, Stefan Wright, Ian Greinert, Jens |
author_sort |
Veloso‐Alarcon, Mario E. |
title |
Variability of Acoustically Evidenced Methane Bubble Emissions Offshore Western Svalbard |
title_short |
Variability of Acoustically Evidenced Methane Bubble Emissions Offshore Western Svalbard |
title_full |
Variability of Acoustically Evidenced Methane Bubble Emissions Offshore Western Svalbard |
title_fullStr |
Variability of Acoustically Evidenced Methane Bubble Emissions Offshore Western Svalbard |
title_full_unstemmed |
Variability of Acoustically Evidenced Methane Bubble Emissions Offshore Western Svalbard |
title_sort |
variability of acoustically evidenced methane bubble emissions offshore western svalbard |
publisher |
Wiley |
publishDate |
2019 |
url |
https://oceanrep.geomar.de/id/eprint/47780/ https://oceanrep.geomar.de/id/eprint/47780/1/Veloso-Alarc-n_et_al-2019-Geophysical_Research_Letters.pdf https://oceanrep.geomar.de/id/eprint/47780/2/grl59359-sup-0001-2019gl082750-si%281%29.pdf https://oceanrep.geomar.de/id/eprint/47780/3/grl59359-sup-0002-2019gl082750-ds01.xlsx https://doi.org/10.1029/2019GL082750 |
geographic |
Arctic Arctic Ocean Svalbard |
geographic_facet |
Arctic Arctic Ocean Svalbard |
genre |
Arctic Arctic Ocean Svalbard |
genre_facet |
Arctic Arctic Ocean Svalbard |
op_relation |
https://oceanrep.geomar.de/id/eprint/47780/1/Veloso-Alarc-n_et_al-2019-Geophysical_Research_Letters.pdf https://oceanrep.geomar.de/id/eprint/47780/2/grl59359-sup-0001-2019gl082750-si%281%29.pdf https://oceanrep.geomar.de/id/eprint/47780/3/grl59359-sup-0002-2019gl082750-ds01.xlsx Veloso‐Alarcon, M. E. , Jansson, P. , De Batist, M. , Minshull, T. A. , Westbrook, G. K. , Pälike, H., Bünz, S. , Wright, I. and Greinert, J. (2019) Variability of Acoustically Evidenced Methane Bubble Emissions Offshore Western Svalbard. Open Access Geophysical Research Letters, 46 (15). pp. 9072-9081. DOI 10.1029/2019GL082750 <https://doi.org/10.1029/2019GL082750>. doi:10.1029/2019GL082750 |
op_rights |
info:eu-repo/semantics/openAccess |
op_doi |
https://doi.org/10.1029/2019GL082750 |
container_title |
Geophysical Research Letters |
container_volume |
46 |
container_issue |
15 |
container_start_page |
9072 |
op_container_end_page |
9081 |
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1766333864612986880 |