Earth’s Cryosphere, 2024, Vol. XXVIII, No. 1, p. 43-52.

GASES AND GAS HYDRATES IN THE EARTH’S CRYOSPHERE

POCKMARKS AND METHANE CONTENT IN LAKE SEDIMENTS OF THE YAMAL PENINSULA

G.E. Oblogov1,*, A.A. Vasiliev1, P.T. Orekhov1,2, A.S. Savvichev3, I.D. Streletskaya4

1 Institute of the Earth’s Cryosphere, Tyumen Scientific Center, Siberian Branch of the Russian Academy of Sciences, Malygina St. 86, Tyumen, 625000 Russia
2 Arctic Research Station of the Institute of Plant and Animal Ecology, Ural Branch of the Russian Academy of Sciences, Zelenaya Gorka St. 21, Labytnangi, 629400 Russia
3 Winogradsky Institute of Microbiology, Federal Research Center of Biotechnology, Russian Academy of Sciences, Leninsky pr. 33, build. 2, Moscow, 119071 Russia
4 Lomonosov Moscow State University, Leninskie Gory 1, Moscow, 119991 Russia
*Corresponding author; e-mail: oblogov@mail.ru

The paper presents the results of studying the appearance and sizes of pockmarks in lakes of three bioclimatic zones of Yamal: northern (arctic), typical, and southern tundra. The diameter of pockmarks in the lakes increases from 1.9 m in the northern tundra to 7.7 m in the southern shrub tundra. Pockmarks occupy from 0.5 to 4.3% of the shallow-water lake area. The content of methane in lake sediments is two or more times higher than in the sediments of the active and transient layers of dominant landscapes. In the typical tundra zone, the methane content in lake sediments is usually about 7 mL/kg, but in some cases it can reach 18 mL/kg and more. Probably, the lakes with the high methane content in bottom sediments are the lakes, where gas emissions can occur and pockmarks can form. After drainage (drying) of the lakes, lake basins (khasyreys) are subjected to freezing, and the cryogenic structure of lake sediments is formed. Eight–ten years after drying, succession changes in the former lake bottoms continue, and the formation of the transient layer is not yet completed.

Keywords: permafrost, pockmarks, lakes, Yamal, methane content in sediments.

Recommended citation: Oblogov G.E., Vasiliev A.A., Orekhov P.T., Savvichev A.S., Streletskaya I.D., 2024. Pockmarks and methane content in lake sediments of the Yamal Peninsula. Earth’s Cryosphere XXVIII (1), 43–52.