Southern and Central Baikal, 4 - 14 October 2016, RV “G. Titov”

Southern and Central Baikal, 4 - 14 October 2016, RV “G. Titov”

The fieldworks were conducted on board RV “G.Titov” in the southern and central basins of Lake Baikal within the State Projects “Change of abiotic and biotic characteristics of the Lake Baikal ecosystem affected by natural and anthropogenic factors” (headed by T. Khodzher) and “Dynamics of heat-and-mass transfer in Lake Baikal…” (headed by N. Granin). The expedition was aimed at i) testing a new method of measuring concentration of dissolved methane (CH4) using paraphase analysis and vacuum degassing; ii) applying artificial air for the first time as an intermediate gas with standardized methane content; iii) measuring methane concentration in gas using two chromatographs equipped with photoionization detectors, SRI8610 (USA) and ECHO-EW (Russia); and iv) monitoring known gas seepages and searching for new ones in the areas of potential gas discharge that had not been included in the previous acoustic survey. A series of experiments were performed to reduce estimation error of dissolved methane concentration. Bubbling gas seepages registered previously were also monitored. Some gas seepages (Malenky, Novosibirsk, and Khoboy) are currently inactive. This phenomenon is typical of Malenkiy and Novosibirsk bubbling gas seepages demonstrating variable activity, whereas it was the first case registered for the Khoboy seepage. No new deep gas seepages were found during this expedition. However, due to investigations performed in the shallow areas of the Selenga River Delta, it was possible to detect new shallow gas seepages in this region.