1. Stable carbon isotope fractionation during methanogenesis in three boreal peatland ecosystems
- Author
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Pierre E. Galand, Kim Yrjälä, Ralfi Conrad, General Microbiology, and Forest Ecology and Management
- Subjects
metanogeneesi ,Peat ,010504 meteorology & atmospheric sciences ,Methanogenesis ,lcsh:Life ,Ombrotrophic ,01 natural sciences ,isotooppinen fraktiointi ,03 medical and health sciences ,Isotope fractionation ,lcsh:QH540-549.5 ,Ecosystem ,Organic matter ,Biogeokemia ,Ecology, Evolution, Behavior and Systematics ,0105 earth and related environmental sciences ,Earth-Surface Processes ,2. Zero hunger ,chemistry.chemical_classification ,0303 health sciences ,030306 microbiology ,Stable isotope ratio ,Ecology ,lcsh:QE1-996.5 ,15. Life on land ,lcsh:Geology ,lcsh:QH501-531 ,chemistry ,13. Climate action ,Isotopes of carbon ,lcsh:Ecology ,118 Biological sciences - Abstract
The degradation of organic matter to CH4 and CO2 was investigated in three different boreal peatland systems in Finland, a mesotrophic fen (MES), an oligotrophic fen (OLI), and an ombrotrophic peat (OMB). MES had similar production rates of CO2 and CH4, but the two nutrient-poor peatlands (OLI and OMB) produced in general more CO2 than CH4. δ13C analysis of CH4 and CO2 in the presence and absence methyl fluoride (CH3F), an inhibitor of acetoclastic methanogenesis, showed that CH4 was predominantly produced by hydrogenotrophic methanogenesis and that acetoclastic methanogenesis only played an important role in MES. These results, together with our observations concerning the collective inhibition of CH4 and CO2 production rates by CH3F, indicate that organic matter was degraded through different paths in the mesotrophic and the nutrient-poor peatlands. In the mesotrophic fen, the major process is canonical fermentation followed by acetoclastic and hydrogenotrophic methanogenesis, while in the nutrient-poor peat, organic matter was apparently degraded to a large extent by a different path which finally involved hydrogenotrophic methanogenesis. Our data suggest that degradation of organic substances in the oligotrophic environments was incomplete and involved the use of organic compounds as oxidants.
- Published
- 2010