Gas exchange between Baikal and the atmosphere during under-ice period

In the under-ice period, gas exchange between Baikal and the atmosphere is taking place through a system of coastal and perennial fractures and airholes in the ice, as well as through the surface of the ice-free part of the lake at the Angara source [24]. The total area of the open water never exceeds 0.03% of lake water area. The emission of CO2 in the course of ice sublimation over the entire period is ≤0.02 g CO2 from 1 m2. The transport of dissolved gases from under-ice water into the atmosphere is limited by molecular diffusion in microfractions of ice cover. The narrow daily variations of CO2 in the air in lake coastal zone is due to the effect of populated localities on its coast and large coniferous forests, which serve as diffuse sources of CO2, as well as diurnal variations of the direction and velocity of air mass transport by local winds.