Methane Content and Emission in the Typical Tundra and the Southern Tundra of the Western Russian Arctic

The results of studying the emission, content, and isotopic composition of methane in soils of the active layer in the zones of typical and southern shrubby tundra of the western Russian Arctic are presented. Methane in the soils of the active layer is of biogenic origin. The maximum methane contents have been recorded in the bogs and the catchment depressions amounting to 1.11 ± 0.95 mg CH 4 /kg with a maximum value of 4.6 mg CH 4 /kg. In the well-drained landscapes, the methane content is significantly lower. For the bog landscapes, a strong correlation between methane contents in the soils and sums of positive air temperatures has been determined. Climate warming causes an increase in the methane content in the soils of the active layer and higher methane emission. The gradient distribution of the methane content and its isotopic composition in water-saturated and drained soils indicates a significant contribution of the diffusion mechanism to the methane transport to the surface.