Exploring the impacts of climate change and permafrost thaw on microlandscapes, plant species, and carbon cycling of West Siberian peatlands

Abstract:

Methane emissions from northern peatlands depend strongly on environmental conditions, wetland plant species assemblages (via root zone oxidation and plant-aided transport), and soil microbial behavior (via metabolic pathways). Potential future changes in high-latitude climate are expected to include permafrost thaw and thermokarst formation, which may change the distribution of microlandscapes such as hummocks and hollows (and plant species therein) within peatlands. While the responses of wetland methane emissions to potential future climate change have been extensively explored, the effects of future changes in plant species and soil microbial metabolism are not as well studied. We ran the Variable Infiltration Capacity (VIC) land surface model over the West Siberian Lowland (WSL), with methane emissions parameters that vary spatially as a function of microlandscape and the dominant plant species therein, and forced with outputs from 32 CMIP5 models for the RCP4.5 scenario. Here we compare the effects of changes in climate, microlandscapes, and vegetation on predicted wetland CH₄ emissions for the period 2071-2100, relative to the period 1981-2010, in terms of both total annual emissions and the spatial distribution of emissions. We also explore possible acclimatization of soil microbial communities to these changes. Our work indicates the importance of better constraining the responses of wetland plants and soil microbial communities to changes in climate as they are critical determinants of the region’s future methane emissions.