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Variability of acoustically evidenced methane bubble emissions offshore western Svalbard
Veloso‐Alarcón, M.E.; Janson, P.; De Batist, M.; Minshull, T.A.; Westbrook, G.K.; Pälike, H.; Bünz, S.; Wright, I.; Greinert, J. (2019). Variability of acoustically evidenced methane bubble emissions offshore western Svalbard. Geophys. Res. Lett. 46(15): 9072-9081. https://dx.doi.org/10.1029/2019GL082750
In: Geophysical Research Letters. American Geophysical Union: Washington. ISSN 0094-8276; e-ISSN 1944-8007
Peer reviewed article  
Available in  Authors 
    Vlaams Instituut voor de Zee: Non-open access 344033 [ request ]
Keyword
    Marine/Coastal
Authors  Top 
  • Veloso-Alarcón, M.E.
  • Janson, P.
  • De Batist, M.
  • Minshull, T.A.
  • Westbrook, G.K.
  • Pälike, H.
  • Bünz, S.
  • Wright, I.
  • Greinert, J.
Abstract
    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.
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