HR: 1340h
AN: B43B-0145    [Abstracts]
TI: Large Methane Plumes Formed by Hydrate Coated Gas Bubbles from a Deep-Sea Submarine Mud Volcano
AU: * Sauter, E J
EM: esauter@awi-bremerhaven.de
AF: Alfred Wegener Institute for Polar and Marine Research, Am Handelshafen 12, Bremerhaven, 27570 Germany
AU: Muyakshin, S I
EM: smun@appl.sci-nnov.ru
AF: Institute of Applied Physics of the Russian Academy of Sciences, 46 Uljanov Str., Nizhnii Novgorod, 603950 Russian Federation
AU: Charlou, J
EM: Jean.Luc.Charlou@ifremer.fr
AF: Dept. of Marine Geosciences, IFREMER Centre de Brest, DRO/GM, BP 70, Plouzane Cedex, 29280 France
AU: Schlueter, M
EM: mschlueter@awi-bremerhaven.de
AF: Alfred Wegener Institute for Polar and Marine Research, Am Handelshafen 12, Bremerhaven, 27570 Germany
AU: Boetius, A
EM: aboetius@mpi-bremen.de
AF: Max Planck Institute for Marine Microbiology, Celsiusstraáe 1, Bremen, 28359 Germany
AU: Damm, E
EM: edamm@awi-bremerhaven.de
AF: Alfred Wegener Institute for Polar and Marine Research, Am Handelshafen 12, Bremerhaven, 27570 Germany
AU: Foucher, J
EM: Jean.Paul.Foucher@ifremer.fr
AF: Dept. of Marine Geosciences, IFREMER Centre de Brest, DRO/GM, BP 70, Plouzane Cedex, 29280 France
AU: Klages, M
EM: mklages@awi-bremerhaven.de
AF: Alfred Wegener Institute for Polar and Marine Research, Am Handelshafen 12, Bremerhaven, 27570 Germany
AB: Submarine mud volcanoes (SMVs) are major methane sources in the marine environment. Worldwide 10$^{3}$-10$^{5}$ SMVs are believed to release in total about 27 Mt CH$_{4}$ yr$^{-1}$. Results of the last decade $\'{ }$ s research suggest, that most of this methane, primarily released diffusively from deep-sea SMVs is immediately oxidised and, thus, has only little climatic impact. Recent hydroacoustic, visual and geochemical observations performed at Haakon Mosby Mud Volcano (HMMV, 1250 meters water depth) reveal that a considerable amount of methane is released by discharge of bubbles and gas hydrate flakes. Gas bubbles withstand dissolution due to the formation of a gas hydrate skin and, thus, are able to ascend several hundred meters through the water column until leaving the temperature-pressure field of gas hydrate stability. Besides, microbial water column methane oxidation was found to be extremely slow, so that methane potentially escapes to the atmosphere, especially during deep winter mixing. We thus propose a much higher environmental relevance of SMVs than previously assumed.
DE: 4805 Biogeochemical cycles (1615)
DE: 4820 Gases
DE: 3339 Ocean/atmosphere interactions (0312, 4504)
DE: 4259 Ocean acoustics
DE: 1600 GLOBAL CHANGE (New category)
SC: Biogeosciences [B]
MN: 2004 AGU Fall Meeting