CH4 and CO2 Fluxes from the Surface of Boreal Lakes in the Arkhangelsk Region in Spring and Summer

The paper presents the estimates of spatial and seasonal variability of the greenhouse gases (CH4 and CO2) fluxes into the atmosphere from the boreal lake surface and the volume of these emissions in the spring and summer of 2022. The lakes of the Arkhangelsk region with different morphometric, hydrological, and hydrochemical characteristics were chosen as the objects of the study. The results showed that the CH4 fluxes from the lake surface varied in the ranges of 0.39–3.7 mg/m2 per day (spring) and 2.7–12.4 mg/m2 per day (summer), while the CO2 fluxes varied within 0.48–16.8 g/m2 per day (spring) and –0.47…14.1 g/m2 per day (summer). Specific CH4 fluxes were smaller in the spring, while CO2 fluxes were smaller in the summer, when several humic lakes became a sink for CO2. Depending on a season, the spatial variability of CH4 and CO2 fluxes reached 72 and 188%, respectively. It has been shown that spatial variability can introduce significant uncertainty into the estimated values of emissions: by 2.7 times for CH4 and by 3–6 times for CO2.