Methane Emission from Lakes in the North of Western Siberia

This paper presents the results of methane flux field measurements on thermokarst lakes of the Russian north on three key sites: foothills of the Polar Urals, coast of the Kara Sea and the northwestern part of the Yamal Peninsula. 13 lakes were studied and about 500 methane fluxes were measured by the floating closed chamber method. The results showed most of the fluxes does not exceed 8 mgCH4 m–2 h–1. For larger values, a statistically significant correlation with the wind speed was found, determining in high degree the intensity of gas exchange on the water–atmosphere boundary. The exceptions are measurements in zone of lake methane seeps. For most lakes, the greatest scatter of measured fluxes was observed in the shallow part. The diurnal dynamics of methane fluxes was approximated by a sinusoidal function. For the presented lakes, the range of emission assessment is 0.23–775.38 gCH4 h–1. Obtained results are important material for estimating regional methane emission from the surface of thermokarst lakes in the tundra zone.