Methane in Water and Bottom Sediments of Lake Baikal

Resumo

The distribution of methane concentration measured in 2014 and 2015 in different parts of Lake Baikal has been analyzed. In the period of expedition studies, methane concentration in lake water and bottom sediments varied from <0.1 to 13.9 µL/dm³ (on the average, 0.7 µL/dm³) and from <0.01 to 3.69 µg/g dry residue (on the average, 0.34 µg/g). The maximal concentrations of methane in water and bottom sediments of the lake were typical of the northern area, which receives waters of the Upper Angara and Kichera, and at some stations on a profile running along the mouth area of the Selenga R., as well as stations in the zone of underwater discharge of wastewater from Baikal’sk City and the Baikal Pulp and Paper Plant (BPPP), which was closed down in 2013. The presence of higher or lower methane concentrations in the examined upper horizons of Lake Baikal deposits is due to the differences in the level of anthropogenic impact; variations in sedimentation conditions, which determine the grain-size distribution and the concentration of organic matter, and, as a consequence, the rate of methanogenesis.