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Title: Widespread methane seepage along the continental margin off Svalbard - from Bjørnøya to Kongsfjorden

Abstract

Numerous articles have recently reported on gas seepage offshore Svalbard, because the gas emission from these Arctic sediments was thought to result from gas hydrate dissociation, possibly triggered by anthropogenic ocean warming. We report on findings of a much broader seepage area, extending from 74° to 79°, where more than a thousand gas discharge sites were imaged as acoustic flares. The gas discharge occurs in water depths at and shallower than the upper edge of the gas hydrate stability zone and generates a dissolved methane plume that is hundreds of kilometer in length. Data collected in the summer of 2015 revealed that 0.02–7.7% of the dissolved methane was aerobically oxidized by microbes and a minor fraction (0.07%) was transferred to the atmosphere during periods of low wind speeds. Most flares were detected in the vicinity of the Hornsund Fracture Zone, leading us to postulate that the gas ascends along this fracture zone. The methane discharges on bathymetric highs characterized by sonic hard grounds, whereas glaciomarine and Holocene sediments in the troughs apparently limit seepage. The large scale seepage reported here is not caused by anthropogenic warming.

Authors:
 [1];  [1];  [2];  [3];  [1];  [3];  [1];  [1];  [1];  [1];  [1]
  1. Univ. of Bremen (Germany). Dept. of Geosciences. Center for Marine Environmental Sciences
  2. Oregon State Univ., Corvallis, OR (United States). College of Oceanic and Atmospheric Sciences
  3. Alfred Wegener Inst. Helmholtz Centre for Polar and Marine Research, Bremerhaven (Germany)
Publication Date:
Research Org.:
Oregon State Univ., Corvallis, OR (United States); Univ. of Bremen (Germany)
Sponsoring Org.:
USDOE Office of Fossil Energy (FE); German Research Foundation (DFG); Hanse-Wissenschaftskolleg (HWK) Foundation (Germany); Federal Ministry for Economic Affairs and Energy (BMWi) (Germany)
Contributing Org.:
Alfred Wegener Inst. Helmholtz Centre for Polar and Marine Research, Bremerhaven (Germany)
OSTI Identifier:
1361682
Grant/Contract Number:
FE0013531; MA 3961/2-1; 03SX346B
Resource Type:
Journal Article: Accepted Manuscript
Journal Name:
Scientific Reports
Additional Journal Information:
Journal Volume: 7; Journal ID: ISSN 2045-2322
Publisher:
Nature Publishing Group
Country of Publication:
United States
Language:
English
Subject:
54 ENVIRONMENTAL SCIENCES; Carbon cycle; Environmental impact; Marine chemistry

Citation Formats

Mau, S., Romer, M., Torres, M. E., Bussmann, I., Pape, T., Damm, E., Geprags, P., Wintersteller, P., Hsu, C. -W., Loher, M., and Bohrmann, G. Widespread methane seepage along the continental margin off Svalbard - from Bjørnøya to Kongsfjorden. United States: N. p., 2017. Web. doi:10.1038/srep42997.
Mau, S., Romer, M., Torres, M. E., Bussmann, I., Pape, T., Damm, E., Geprags, P., Wintersteller, P., Hsu, C. -W., Loher, M., & Bohrmann, G. Widespread methane seepage along the continental margin off Svalbard - from Bjørnøya to Kongsfjorden. United States. doi:10.1038/srep42997.
Mau, S., Romer, M., Torres, M. E., Bussmann, I., Pape, T., Damm, E., Geprags, P., Wintersteller, P., Hsu, C. -W., Loher, M., and Bohrmann, G. Thu . "Widespread methane seepage along the continental margin off Svalbard - from Bjørnøya to Kongsfjorden". United States. doi:10.1038/srep42997. https://www.osti.gov/servlets/purl/1361682.
@article{osti_1361682,
title = {Widespread methane seepage along the continental margin off Svalbard - from Bjørnøya to Kongsfjorden},
author = {Mau, S. and Romer, M. and Torres, M. E. and Bussmann, I. and Pape, T. and Damm, E. and Geprags, P. and Wintersteller, P. and Hsu, C. -W. and Loher, M. and Bohrmann, G.},
abstractNote = {Numerous articles have recently reported on gas seepage offshore Svalbard, because the gas emission from these Arctic sediments was thought to result from gas hydrate dissociation, possibly triggered by anthropogenic ocean warming. We report on findings of a much broader seepage area, extending from 74° to 79°, where more than a thousand gas discharge sites were imaged as acoustic flares. The gas discharge occurs in water depths at and shallower than the upper edge of the gas hydrate stability zone and generates a dissolved methane plume that is hundreds of kilometer in length. Data collected in the summer of 2015 revealed that 0.02–7.7% of the dissolved methane was aerobically oxidized by microbes and a minor fraction (0.07%) was transferred to the atmosphere during periods of low wind speeds. Most flares were detected in the vicinity of the Hornsund Fracture Zone, leading us to postulate that the gas ascends along this fracture zone. The methane discharges on bathymetric highs characterized by sonic hard grounds, whereas glaciomarine and Holocene sediments in the troughs apparently limit seepage. The large scale seepage reported here is not caused by anthropogenic warming.},
doi = {10.1038/srep42997},
journal = {Scientific Reports},
number = ,
volume = 7,
place = {United States},
year = {Thu Feb 23 00:00:00 EST 2017},
month = {Thu Feb 23 00:00:00 EST 2017}
}

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