SEMINAR: GEOTOPICS: MONDAY (02/22) 3.15PM - Dr. Rick Colwell "Biogeochemical Exhalations: Microbial Methane in Marine Sediments"

[Marco Bagnardi <mbagnardi@rsmas.miami.edu>]

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3:15 PM, Monday, February 22nd, 2010
SLAB Seminar Room, S/A 103

Refreshments 3:00 PM

Dr. Frederick (Rick) Colwell

College of Oceanic and Atmospheric Sciences, Oregon State University

 

"Biogeochemical Exhalations: Microbial Methane in Marine Sediments"

Hydrates in marine sediments of continental shelves contain huge quantities of biogenic methane held in place by high pressures and low temperatures. This methane is important as a potential greenhouse gas (if it were to escape to the atmosphere), a source of energy, or as a factor in seafloor stability. However, knowledge of the microbial communities that generate this methane is limited. Our microbiological studies of hydrate bearing sediments focus on determining: 1) the in situ activities of the methanogens and 2) the environmental controls on the distribution of these cells in the sediments. By linking accurate estimates of methanogen numbers at specific depths in hydrate-bearing and adjoining strata with the rates of methanogenesis when these cells are starved – a typical condition for many subsurface cells – we derive realistic in situ methane production rates for these communities. Such rates along with the recognition of the environmental constraints that permit microbial life to exist are required for models that describe the rate of hydrate formation or the amount of methane in the sediments. 

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Marco Bagnardi

mbagnardi@rsmas.miami.edu