Oxidation of methane in the water column of Lake Baikal

The rate of aerobic oxidation of methane was calculated based on average profiles of the tritiumhelium age of the Baikal waters and concentrations of the dissolved methane in the water column. In the deep lake zone (>200 m), the intensity of oxidation vertically decreases and is (2–0.3) × 10−2 nl CH4l−1 days−1 in southern and central Baikal and (2.8–1.0) × 10−2 nl CH4 l−1 days−1 in northern Baikal. The effective coefficient of the oxidation rate in the lake depressions is 3.6 × 10−4, 3.3 × 10−4, and 3.7 × 10−4 days−1, respectively. At current methane concentrations in the water column, about 80 t of methane is oxidized per year. Oxidation of the dissolved methane in the water column was estimated at a possible increase of its concentration.