Advanced search
1 file | 1.80 MB

Atmospheric methane flux from bubbling seeps : spatially extrapolated quantification from a Black Sea shelf area

Author
Organization
Abstract
Bubble transport of methane from shallow seep sites in the Black Sea west of the Crimea Peninsula between 70 and 112 m water depth has been studied by extrapolation of results gained through different hydroacoustic methods and direct sampling. Ship-based hydroacoustic echo sounders can locate bubble releasing seep sites very precisely and facilitate their correlation with geological or other features at the seafloor. Here, the backscatter strength of a multibeam system was integrated with single-beam data to estimate the amount of seeps/m2 for different backscatter intensities, resulting in 2709 vents in total. Direct flux measurements by submersible revealed methane fluxes from individual vents of 0.32–0.85 l/min or 14.5–37.8 mmol/min at ambient pressure and temperature conditions. A conservative estimate of 30 mmol/min per site was used to estimate the flux into the water to be 1219–1355 mmol/s. The flux to the atmosphere was calculated by applying a bubble dissolution model taking release depth, temperature, gas composition, and bubble size spectra into account. The flux into the atmosphere (3930–4533 mol/d) or into the mixed layer (6186–6899 mol/d) from the 21.8 km2 large study area is three times higher than independently measured fluxes of dissolved methane for the same area using geochemical methods (1030–2495 mol/d). The amount of methane dissolving in the mixed layer is 2256–2366 mol/d. This close match shows that the hydroacoustic approach for extrapolating the number of seeps/m2 and the applied bubble dissolution model are suitable to extrapolate methane fluxes over larger areas.
Keywords
SEDIMENTS, GAS SEEPS, MUD VOLCANOS, HYDRATE DEPOSITS, HYDROCARBON SEEPS, DNEPR PALEO-DELTA, GEOLOGIC EMISSIONS, ENVIRONMENT, SURFACE, DYNAMICS

Downloads

  • (...).pdf
    • full text
    • |
    • UGent only
    • |
    • PDF
    • |
    • 1.80 MB

Citation

Please use this url to cite or link to this publication:

Chicago
Greinert, Jens, Daniel F McGinnis, Lieven Naudts, Peter Linke, and Marc De Batist. 2010. “Atmospheric Methane Flux from Bubbling Seeps : Spatially Extrapolated Quantification from a Black Sea Shelf Area.” Journal of Geophysical Research-oceans 115.
APA
Greinert, J., McGinnis, D. F., Naudts, L., Linke, P., & De Batist, M. (2010). Atmospheric methane flux from bubbling seeps : spatially extrapolated quantification from a Black Sea shelf area. JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS, 115.
Vancouver
1.
Greinert J, McGinnis DF, Naudts L, Linke P, De Batist M. Atmospheric methane flux from bubbling seeps : spatially extrapolated quantification from a Black Sea shelf area. JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS. 2010;115.
MLA
Greinert, Jens, Daniel F McGinnis, Lieven Naudts, et al. “Atmospheric Methane Flux from Bubbling Seeps : Spatially Extrapolated Quantification from a Black Sea Shelf Area.” JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS 115 (2010): n. pag. Print.
@article{854354,
  abstract     = {Bubble transport of methane from shallow seep sites in the Black Sea west of the Crimea Peninsula between 70 and 112 m water depth has been studied by extrapolation of results gained through different hydroacoustic methods and direct sampling. Ship-based hydroacoustic echo sounders can locate bubble releasing seep sites very precisely and facilitate their correlation with geological or other features at the seafloor. Here, the backscatter strength of a multibeam system was integrated with single-beam data to estimate the amount of seeps/m2 for different backscatter intensities, resulting in 2709 vents in total. Direct flux measurements by submersible revealed methane fluxes from individual vents of 0.32–0.85 l/min or 14.5–37.8 mmol/min at ambient pressure and temperature conditions. A conservative estimate of 30 mmol/min per site was used to estimate the flux into the water to be 1219–1355 mmol/s. The flux to the atmosphere was calculated by applying a bubble dissolution model taking release depth, temperature, gas composition, and bubble size spectra into account. The flux into the atmosphere (3930–4533 mol/d) or into the mixed layer (6186–6899 mol/d) from the 21.8 km2 large study area is three times higher than independently measured fluxes of dissolved methane for the same area using geochemical methods (1030–2495 mol/d). The amount of methane dissolving in the mixed layer is 2256–2366 mol/d. This close match shows that the hydroacoustic approach for extrapolating the number of seeps/m2 and the applied bubble dissolution model are suitable to extrapolate methane fluxes over larger areas.},
  articleno    = {C01002},
  author       = {Greinert, Jens and McGinnis, Daniel F and Naudts, Lieven and Linke, Peter and De Batist, Marc},
  issn         = {0148-0227},
  journal      = {JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS},
  keywords     = {SEDIMENTS,GAS SEEPS,MUD VOLCANOS,HYDRATE DEPOSITS,HYDROCARBON SEEPS,DNEPR PALEO-DELTA,GEOLOGIC EMISSIONS,ENVIRONMENT,SURFACE,DYNAMICS},
  language     = {eng},
  pages        = {18},
  title        = {Atmospheric methane flux from bubbling seeps : spatially extrapolated quantification from a Black Sea shelf area},
  url          = {http://dx.doi.org/10.1029/2009JC005381},
  volume       = {115},
  year         = {2010},
}

Altmetric
View in Altmetric
Web of Science
Times cited: