Suchergebnisse

The paper presents the results of field measurements of methane fluxes into the atmosphere from thermokarst lakes located on the Russian Federation territory on the three key sites: foothills of the Polar Urals, coast of the Kara Sea and the northwestern part of the Yamal Peninsula. A total of 13 lakes were studied and about 500 methane fluxes were measured by the floating chamber method. The results showed most of the fluxes does not exceed 8 mg CH4 m–2 h–1. For more significant values, a statistically significant correlation with the wind speed was revealed, which largely determines 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 lakes presented in the work, the range of emission assessment is 0.23–775.38 g CH4 h–1. Obtained results are important material for estimating regional methane emission from the surface of thermokarst lakes in the tundra zone.

The article presents the results of long-term field studies of methane in the upper part of permafrost for the different geomorphological levels of Central Yakutia. Patterns of spatial distribution of methane content across different landscapes were found. The highest concentrations of methane are found in alas deposits, the major role of methane in the conservation there goes to the moment of freezing the thermokarst lake draining. The difference in methane content in the sediments of the Late Pleistocene Ice Complex on the left and the right bank of the river Lena was identified. That is likely caused by the conditions of ice complex formation.