Developing and Testing of Bioreactors for Methane Hydrate Biogeochemical Studies in the Laboratory

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This technology development project addresses methane hydrates, which represent the most abundant hydrocarbon source on Earth. Decades of geochemical studies have established the importance of anaerobic methane oxidation (AMO) in methane hydrate containing marine sediments, but the organisms responsible for this major process in the Carbon cycle have never been isolated; and no pure cultures of microbes capable of net AMO have yet been obtained. The project entails an interdisciplinary integrated experimental and field program to determine the mechanism of AMO by following AMO under controlled variable-defined laboratory conditions that provide a thermodynamically favorable environment for microbial methane consumption over methane production. In order to create conditions which support AMO, newly designed anaerobic high pressure/low temperature bioreactors will be constructed and tested. The source of microorganisms inoculated into the bioreactors will come from sediment samples with AMO activity. These sediments will be recovered under in situ conditions from the Cascadia Margin off the Oregon coast. A variety of geochemical assays on the culture medium and the resulting methane hydrate will be performed during enrichments in the bioreactor, and the biogeochemistry of the environment will be continuously monitored and characterized. The bioreactors will provide an experimental platform for future analyses of isotopically labeled biogeochemical equilibrium and kinetic experiments under well defined controlled conditions.