Methanogenesis and methanogenic pathways in a peat from subarctic permafrost
Tóm tắt
Few studies have dealt so far with methanogenic pathways and populations in subarctic and arctic soils. We studied the effects of temperature on rates and pathways of CH4 production and on the relative abundance and structure of the archaeal community in a mildly acidic peat from a permafrost region in Siberia (67°N). We monitored the production of CH4 and CO2 over time and measured the consumption of Fe(II), ethanol and volatile fatty acids. All experiments were performed with and without specific inhibitors [2‐bromoethanesulfonate (BES) for methanogenesis and CH3F for acetoclastic methanogenesis]. The optimum temperature for methanogenesis was between 26°C and 28°C [4.3 μmol CH4 (g dry weight)−1 day−1], but the activity was high even at 4°C [0.75 μmol CH4 (g dry weight)−1 day−1], constituting 17% of that at 27°C. The population structure of archaea was studied by terminal restriction fragment length polymorphism analysis and remained constant over a wide temperature range. Acetoclastic methanogenesis accounted for about 70% of the total methanogenesis. Most 16S rRNA gene sequences clustered with
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