Evaluation of the dynamics of the carbon balance for peatlands of the southern-taiga subzone of West Siberia (Tomsk region)

The aim of the study was to assess carbon reserves and balance in oligotrophic and eutrophic bogs of the souther- taiga subzone of West Siberia. Location and time of the study. The study was carried out at the field station "Vasyuganye" (56° 57′ N, 82° 30′ E) of the Institute for Monitoring Climatic and Ecological Systems of the Siberian Branch of the Russian Academy of Sciences in oligotrophic and eutrophic undisturbed native. Field work was carried out during the growing seasons (May-September) from 1999 to 2012. Methods. The estimation of biological productivity (phytomass stocks and net primary production) was carried out by the cutting method, underground production was determined by the method of monoliths. The rate of transformation of plant residues of peat-forming plants was assessed using the method of partially isolated samples. The rate of decomposition and loss of carbon was calculated as a percentage of the original mass and the original carbon content. CO2 emissions were measured by the chamber method. The annual CO2 flux from the surface of the peat deposit was modeled on the basis of the data obtained as a result of field measurements of CO2 emission. Additional carbon losses, such as methane emissions, winter emissions of CO2 and methane, and carbon removal with bog waters, were estimated based on published data. The annual carbon balance for the studied mire ecosystems was calculated as the difference between the carbon fluxes and NPP of bog ecosystems. Results. The main carbon pools in mire ecosystems are concentrated in peat deposits. On average, for the study area, they are 74 kg/m2 for the oligotrophic bog, and 161 kg/m2 for the eutrophic one. Carbon reserves in the form of plant organic matter are much lower (50 times on average). As a result of many years of research, it was revealed that with a high interannual variability of the carbon balance in the period from 1999 to 2012, there are no significant trends in temporal changes of the carbon balance for the studied ecosystems. The annual absorption of carbon by the peatland ecosystems of the key site "Bakcharsky" with an area of 212 thousand hectares is about 3 × 105 tons. Conclusion. Peatland ecosystems of the southern-taiga subzone of West Siberia are currently a constant sink of carbon and, as such, being sustainable natural formations, contribute to climate change mitigation.