The effect of geocryological conditions and soil properties on the spatial variation in the CO2 emission from flat-topped peat mounds in the isolated permafrost zone of Western Siberia

The active layer thickness, CO2 emission, and contents of organic substances (including the total organic carbon, labile carbon, and the carbon of microbial biomass) in the soils of flat-topped peat mounds in the area of the Nadym Experimental Station in the north of Western Siberia (experimental site CALM R1) are characterized by considerable spatial variability. The low values of the CО2 emission are confined to the microelevations on the peatland surface. The high values of the emission (>200 mg CO2/(m2 h)) are typical of the soils with the highest content of the carbon of microbial biomass and the lowest content of the labile organic carbon. The soils of elevated flat-topped peat mounds statistically differ from the soils of waterlogged mires in the contents of total, labile, and microbial carbon and in the CO2 emission values. Though the soils of elevated flat-topped peat mounds are characterized by the high content of the carbon of microbial biomass (4260 ± 880 mg С/kg soil), the CO2 emission from them is low (158 ± 23 mg CO2/(m2 h)), which is explained by the structure of microbial communities in the cryogenic soils and by the effect of specific hydrothermic conditions.