HR: 1340h
AN: B43B-0147    [Abstracts]
TI: Methane Driven Microbial Ecosystems At Mud Volcanoes And Other Types Of Cold Seeps
AU: * Boetius, A
EM: aboetius@mpi-bremen.de
AF: Max Planck Institute for Marine Microbiology, Celsiusstr. 1, Bremen, 28203 Germany
AU: Niemann, H
EM: hniemann@mpi-bremen.de
AF: Max Planck Institute for Marine Microbiology, Celsiusstr. 1, Bremen, 28203 Germany
AU: Tina, L
EM: tloeseka@mpi-bremen.de
AF: Max Planck Institute for Marine Microbiology, Celsiusstr. 1, Bremen, 28203 Germany
AU: DeBeer, D
EM: dbeer@mpi-bremen.de
AF: Max Planck Institute for Marine Microbiology, Celsiusstr. 1, Bremen, 28203 Germany
AU: Sauter, E
EM: esauter@awi-bremerhaven.de
AF: Alfred Wegener Institute for Polar and Marine Research, Am Handelshafen 12, Bremerhaven, 27515 Germany
AU: Schlueter, M
EM: mschlueter@awi-bremerhaven.de
AF: Alfred Wegener Institute for Polar and Marine Research, Am Handelshafen 12, Bremerhaven, 27515 Germany
AU: Foucher, J
EM: jean.paul.foucher@ifremer.fr
AF: IFREMER, Technopole de Brest-Iroise, Plouzane, Brest, 29289 France
AB: Ocean margin research of the last decade has provided evidence for distinct microbial habitats fueled by methane, which harbor high biomasses but low diversities of bacteria and archaea. Such microbial ecosystems are found above gas hydrates and at mud volcanoes, pockmarks and other methane-driven cold seep systems. A key process in the emission of methane and sulfide at such seeps, in the turnover of elements and in the formation of carbonate is the anaerobic oxidation of methane (AOM). AOM is the major biological sink of methane in the ocean and crucial in balancing the emission of this important greenhouse gas into the atmosphere. The microbial oxidation of methane with sulfate as electron acceptor provides sulfide as an energy source to chemosynthetic communities of similar biomass and diversity as those of hydrothermal vents. We are just beginning to understand microbial methane cycling in anoxic habitats and its regulation of gas emission, its link to the sulfur cycle, and its relevance in transforming subsurface energy to support benthic communities at the seafloor. A priority of future research is to investigate and visualize the interaction between geological structures forming habitats for anoxic life and microbial communities which shape these structures through their activities such as gas production and consumption, petroleum degradation, microbial calcification. Systems like the Haakon Mosby mud volcano of the Barents Sea and the newly discovered mud volcanoes of the E. Mediterranean Nile fan represent distinct geological structures on continental margins, and are excellent natural laboratories for investigation of microbial ecosystems and cold seep communities. Mud volcanoes represent a window to the deep biosphere because they expel subsurface sediments together with fluids and gases from great depth to the surface of the seafloor. As a consequence, a natural gradient develops from the center of the volcano to its outer rim, representing a succession from the freshly emitted subsurface sediments devoid of surface communities, to pioneer microbial communities and finally to high biomasses of cold seep chemosynthetic populations, and associated fauna immigrating from the surrounding slope environment. Based on observational, experimental and theoretical data, this presentation will discuss the questions: Which are the key microorganisms and biogeochemical pathways depending on methane flux? On which timescales do methane-driven microbial ecosystems develop, change and leave imprints in the geosystem? In which ways do geological structures shape the evolution of microbial and cold seep ecosystems?
UR: http://www.mpi-bremen.de/deutsch/biogeo/mumm2.html
DE: 4804 Benthic processes/benthos
DE: 4840 Microbiology
DE: 1050 Marine geochemistry (4835, 4850)
DE: 0330 Geochemical cycles
DE: 0400 Biogeosciences
SC: Biogeosciences [B]
MN: 2004 AGU Fall Meeting