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.