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Geomicrobiology of methanogens in peatlands of the discontinuous permafrost zone of boreal western continental Canada.
YAVITT, JOSEPH*,1, 1 Cornell University, Ithaca, NY
ABSTRACT- Permafrost near its southern limit in western Canada is restricted mostly to ombrotrophic peatlands. Recent evidence that permafrost has been degrading in this region has focused attention on potential biological and chemical changes in peatland ecosystems. For example, 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, I examined the biogeochemistry of methane and molecular analyses of methanogens in peat cores from three contrasting peatland sites in boreal Alberta. Peat from the active surface layer of permafrost bogs had very low rates methane production, and I was unable to amplify 16s rDNA using Archaea-specific primers in five of six peat samples. Peat from continental bogs supported moderate rates of methane production, but only in peat located close to the mean water table level. In contrast, peat from internal lawns had very high rates of methane production and appeared to have a wider diversity of methanogens adapted to a wider range of substrates compared to methanogens from the continental bogs. I speculate that methanogens in internal lawns survived in a dormant state in the permafrost until it melted.
KEY WORDS: methane, peatland