## 3 Results and Discussion  
The results of CO\({}_{2}\) flux measurements in 2017 and 2018 showed that the mean daily gross primary production (GPP) significantly exceeded ecosystem respiration (ER) for the period between mid-June to the end of August for both years, i.e., the palsa mine during the growing season served as a sink of CO\({}_{2}\) from the atmosphere. Maximum daily CO\({}_{2}\) uptake rates in 2017 were observed at the beginning of July (about 4.5 gC m\({}^{-2}\) d\({}^{-1}\)), mainly due to high incoming solar radiation, optimal air temperature and sufficient soil moisture conditions after a 2-week rainy period (Figure 2). A high temperature and low precipitation have no significant effect on net CO\({}_{2}\) fluxes despite of the highest rates of ER in the period. From the end of July to the end of August, the difference between CO\({}_{2}\) uptake and CO\({}_{2}\) release is steadily reduced and it was close to zero at end of summer period. The net CO\({}_{2}\) fluxes were positive in September, showing the net efflux of CO\({}_{2}\) into the atmosphere. The temporal variability of CO\({}_{2}\) fluxes since mid-July of 2018 showed a trend quite similar to 2017, mainly due to similar meteorological conditions (Figure 3). Figure 2: Seasonal variability of the mean daily air temperature, precipitation, CO\({}_{2}\) and CH\({}_{4}\) fluxes in the palsa mine in 2017. A close dependence of net CO\({}_{2}\) fluxes on incoming solar radiation and the air temperature is a key feature of CO\({}_{2}\) exchanges in subarctic palsa mite under sufficient moisture conditions. In particular, the similar seasonal variability and maximum CO\({}_{2}\) flux rates in July were detected in subarctic palsa mite in Sweden [7]. The possible effect of permafrost degradation is also a very important topic in GHG flux studies in permafrost areas. It can be expected that the small increase in CO\({}_{2}\) fluxes in the second part of July under high air temperatures can be associated with permafrost thawing. However, as it was shown by [PERSON] et al. [11] from measurements in northern Sweden, the net carbon accumulation of a high-latitude permafrost palsa mite can be similar to permafrost-free peatlands. The temporal variability of CH\({}_{4}\) fluxes was relatively high varying between \(-8.3\) to \(13.6\) mgC m\({}^{-2}\) per day in 2017 and between \(-4.5\) to \(21.8\) mgC m\({}^{-2}\) per day in 2018 (Figures 2 and 3). Such variability was mainly associated with weather conditions, peat aeration, vegetation growth and functioning, nutrient level, peat temperature, permafrost melting and microbial processes responsible for net release of CH\({}_{4}\). The maximum of CH\({}_{4}\) release in 2017 is obtained at the middle of May, at the beginning of June and at the beginning and in the second half of July. Whereas the maximum CH\({}_{4}\) release in May and June is well correlated with time of snow cover melting and soil thawing, other maximums are mainly associated with soil temperature oscillations. Similar close relationships between CH\({}_{4}\) release rate and soil temperature can be found in the July and August of 2018. The periods of methane uptake were detected in early and mid-June 2017, as well as in September 2018. They may be associated with long periods of warm and mostly rainless weather, under decreased soil moisture and ground water level and, as a result of the increased oxidation rate of methane, by soil bacteria. Comparison of the obtained results with previously published data indicates their good correlation with CH\({}_{4}\) flux measurements in other subarctic regions. In particular, similar results were obtained by [PERSON] et al. [12] from soil chamber measurements in a subarctic palsa mite in Finland and by [PERSON] et al. [8] from measurements in the forest-tundra ecotone in northern Siberia. Figure 3: Seasonal variability of the mean daily air temperature, precipitation, CO\({}_{2}\) and CH\({}_{4}\) fluxes in the palsa mite in 2018.