HR: 08:45h
AN: B41F-04 INVITED     [Abstracts]
TI: Methanogenesis and methanogens in peatlands of the discontinuous permafrost zone of boreal western continental Canada
AU: * Yavitt, J B
EM: jby1@cornell.edu
AF: Cornell University, Department of Natural Resources, Ithaca, NY 14853-3001 United States
AU: Basiliko, N
EM: nathan.basiliko@ubc.ca
AF: University of British Columbia, Department of Forest Sciences, Vancouver, BC V6T 1Z4 Canada
AU: Turetsky, M R
EM: mrt@msu.edu
AF: Michigan State University, Department of Plant Biology, East Lansing, MI 48824-1312 United States
AU: Hay, A G
EM: agh5@cornell.edu
AF: Cornell University, Department of Natural Resources, Ithaca, NY 14853-3001 United States
AB: Frozen ground (permafrost) near its southern limit in western Canada is restricted mostly to ombrotrophic (ombro- = rain fed) peatlands. Methane fluxes into the atmosphere are very low for 1) peatlands over permafrost and 2) peatlands with no evidence of permafrost (continental bogs), whereas 3) peatlands over melted permafrost (internal lawns) support very high methane flux rates. To understand these patterns, we examined the biogeochemistry of methane and molecular characteristics of methanogens in peat soil from representative sites in boreal Alberta and Saskatchewan. Peat soil from the active surface layer of permafrost bogs had very low rates of methane production (ca. 20 nmol/g.day), and we were unable to PCR-amplify 16s rRNA gene sequences using Archaea-specific primers in five of six peat samples. Peat soil from continental bogs supported moderate rates of methane production (20 to 600 nmol/g.day), with maximum rates restricted to soil located close to the mean water table level. In contrast, peat from internal lawns had very high rates of methane production (up to 800 nmol/g.day), located extensively in the soil profile. Attendant rates of anaerobic CO2 production were roughly comparable among peatland types. Phylotypes of methanogenic Archaea were mostly from the Methanosarcinales (known acetate users) in peat soil from the internal lawns, whereas Methanobacteriales and Rice Cluster I (both H2/CO2 users) were the dominant phylotypes in peat soil from the continental bogs. Our results suggest that permafrost melting creates an idiosyncratic environment for methanogens and active rates of methanogenesis.
DE: 0315 Biosphere/atmosphere interactions (0426, 1610)
DE: 0400 BIOGEOSCIENCES
SC: Biogeosciences [B]
MN: Fall Meeting 2005