CARBON SEQUESTRATION IN A KARST MIRE OF THE MORDOVIAN RESERVE DURING THE LATE HOLOCENE

The article presents the results of the study of carbon accumulation over the past 3000 years in the Stol-bovoye karst mire located within the Smidovich Mordovian State Nature Reserve on the southern border of the coniferous-deciduous forests of the East European Plain. Minerothrophic (sedge, wood-sedge, grass) and mesotrophic (Sphagnum, grass-Sphagnum, sedge-Sphagnum, cotton grass) types of peat are present in the peat deposits of the Stolbovoye mire. The mire is at the mesotrophic stage of development. The content of organic carbon varies from 37,2 to 53,4% (49,7% on average). The nitrogen content in peat shows significantly higher variations along the core compared to organic carbon, i. e. from 1,1 to 2,6% (the average value is 1,9%). The total carbon pool in the Stolbovoye mire is about 6,7 kg/m2. The data obtained showed that a fast-growing peatland is capable to sequester large amounts of atmospheric carbon. The carbon accumulation rate in the studied peatland varies from 32,0 to 158,4 g C/m2/yr, with an average of 68,9 g C/m2/yr, which is significantly higher than the average carbon accumulation rates in different types of peatlands during the Holocene. A relationship between carbon accumulation rate and climatic changes over the past 3000 years was not revealed. A significant increase in the rate of carbon accumulation at a depth of 60 cm (480 cal. years BP) could be associated with the high productivity of vascular plants even at higher levels of mineralization/humification of their residues.