ИСТИНА

The spatial distribution of CO2 efflux and content of water-extractable organic carbon are strongly correlated with hypsometric levels (r = –0,33, and r = –0,42 respectively, p <0,05) in tundra ecosystems. Despite the wide array of changes in both physical (soil temperature, soil moisture) and biological conditions (vegetation composition, content of labile and microbial soil carbon), our results showed that soil CO2 flux did not vary significantly across the transect (taiga–forest tundra–south tundra). However, the depth of the permafrost table differed significantly. This explains the necessity for adequate assessment of spatial variability of the active layer thickness as a significant factor influencing regional CO2 emission and soil biological activity.