Methane Content and Emission in the Permafrost Landscapes of Western Yamal, Russian Arctic

Abstract

We present the results of studies of the methane content in soils of the active layer and underlying permafrost, as well as data on the emission of methane into the atmosphere in the dominant landscapes of typical tundra of the western coast of the Yamal Peninsula. A detailed landscape map of the study area was compiled, the dominant types of landscapes were determined, and vegetation cover was described. We determined that a high methane content is characteristic of the wet landscapes: peat bogs within the floodplains, water tracks, and lake basins. Average values of the methane content in the active layer for such landscapes varied from 2.4 to 3.5 mL (CH4)/kg, with a maximum of 9.0 mL (CH4)/kg. The distribution of methane in studied sections is characterized by an increase in its concentration with depth. This confirms the diffuse mechanism of methane transport in the active layer and emission of methane into the atmosphere. The transition zone of the upper permafrost contains 2.5–5-times more methane than the active layer and may become a significant source of methane during the anticipated permafrost degradation. Significant fluxes of methane into the atmosphere of 2.6 mg (CH4) * m−2 * h−1 are characteristic of the flooded landscapes of peat bogs, water tracks, and lake basins, which occupy approximately 45% of the typical tundra area.