Stable Carbon composition of Methane in Eurasian Peatlands: CH4 production, transport and oxidation

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Eurasian peatlands are important sources of the greenhouse gas CH4 to the atmosphere. However, it is not clear whether the intensity of CH4 flux within boreal peatlands would alter in a changing climate. Here, we propose to narrow this knowledge gap by investigating mechanisms of the CH4 balance between production within peat profile and consumption in peat oxidative zones as well as CH4 transport mechanisms. The investigation will be conducted along a maritimecontinental transect spanning from Finland to one of largest peatlands areas in North-Western Russia. At each site, we will measure (i) porewater CH4 concentrations and emitted CH4 efflux, (ii) concentrations of acetates as substrates for methanogenesis; (iii) stable C isotopic composition of porewater- and emitted CH4 to assess the sources of methanogenesis, CH4-oxidative potential and possible mechanisms of CH4 transport from peat depth to the atmosphere. Obtained data will improve the knowledge about mechanisms of the CH4 turnover on both spatial (from micro-scale - peatland’s microforms: hummocks, lawns, hollows - to macro-scale along a maritime-continental transect) and temporal (over spring-summer seasons) dimensions. Knowledge of the specific mechanisms of CH4 turnover within boreal peatlands will help in the development of the new- and adjustment of the existing global- and regional models of C balance.