Achieving the overall goal of carbon neutrality in the middle of 21th century requires comprehensive information about anthropogenic and natural emission and uptake of greenhouse gases (GHG) in different biomes of the world. The area of Northern Eurasia is represented by extremely diverse plant communities and soil types situated within various natural zones including tundra, forest-tundra, forest, wetland and grasslands, and their contributions into the global and regional atmospheric GHG budgets are still very poorly investigated. Information about GHG fluxes in this area can be also very important because the largest part of Northern Eurasia is underlined by continuous permafrost. The thawing of permafrost due to global warming may result in sharp increase of GHG emission into the atmosphere that can have a significant impact on the climate. The relevant information on GHG fluxes in those ecosystems could obviously serve as a basis for a reliable prediction of future climate change and mitigation measures.

The main goal of the study was to obtain new experimental data on seasonal variability of carbon dioxide (CO₂) and methane (CH₄) fluxes in a subarctic palsa mire, as well as to assess the sensitivity of these CO₂ and CH₄ fluxes to changes in environmental conditions. Experimental area is situated at the boundary between northern taiga and forest-tundra ecotone at the North of Central Siberia in Turukhansky district of Krasnoyarsk Krai of Russia. Vegetation of the peatland is a mosaic of perennial frost mounds and peat plateau with a height of 1-1.5 m and flat, mostly unfrozen hollows, 150-200 m wide. Lichens and feather mosses in combination with Betula nana L., Ledum palustre L., Rubus chamaemorus L. and bare peat as well, occupy the mounds, while various species of Carex, feather mosses and herbs are common within the hollows. The CO₂ and CH₄ turbulent fluxes at our site were continuously measured using the eddy covariance method. Intensive field campaigns were conducted from the late winter (early May) to fall (early October) since 2016 (from snow to snow).

The results of field measurements of 2017 and 2018 years showed that the mean daily CO₂ uptake rates significantly exceeded CO₂ emissions for the period between mid-June to the end of August for both years, i.e. the palsa mire ecosystem in the growing season served as a sink of CO₂ from the atmosphere. Maximum CO₂ uptake rate (about 4.5 gC m^-2 d^-1) were observed in July mainly due to high incoming photosynthetically active radiation (PAR) and optimal air temperature and soil moisture conditions. In the late August the balance between CO₂ uptake and CO₂ emissions was close to zero. The net CO₂ fluxes in September were positive showing the net efflux of CO₂ into the atmosphere. Temporal variability of CH₄ fluxes was relatively high and varied between -28 to 74 mgC m^-2 d^-1. Such variability was mainly associated with weather conditions, peat aeration, vegetation growth and functioning, nutrient level, peat temperature and microbial processes responsible for net release of CH₄.

The field measurements provided by V.Zyrianov and A. Panov were founded by the joint grant of RFBR and Krasnoyarsk Regional Science Foundation (20-45-242908). Landscape description conducted by A.Prokushkin was supported by the grant of the Russian Science Foundation (20-17-00043). The data analysis supervised by A.Olchev was supported the grant of the Russian Science Foundation (22-17-00073).