Carbon Accumulation in Peat Soils of Floodplain Mires of the North-East of the Middle-Russian Upland

Abstract

The study of the structure of peat deposits of the Bolsheberezovskoye and Podkosmovo inundated mires which were formed during the Atlantic – subboreal periods of the Holocene in the valley of the Nepryadva River, in the north-eastern part of the Middle-Russian Upland. The results of the botanical composition of peat deposits showed that the genesis of mires is represented by eutrophic paleocenoses, which accumulated carbon at a rate of 21.8-95 g/m2 per year. The formed eutrophic peat was characterized by a high degree of decomposition (45-55%) and a low rate of vertical growth (on average, 0.3-0.6 mm/year), which is due to the seasonal dynamics of the level of occurrence of mire waters. The carbon content in peat by peat deposit profiles is 14% for the Podkosmovo mire and 31% for the Bolsheberezovskoye mire. The differences are due to the peculiarities of the water-mineral nutrition of the mires, which is manifested in the high content of carbonates and ash content of the Podkosmovo mire. Carbon reserves in peat soils of inundated mires vary from 51.5 up to 125 kg/m2 for horizons with a capacity of 10 cm. This indicator is determined by the intensity of decomposition of plant residues, which depends on the composition and structure of microbial complexes. On the Bolsheberezovskoye mire the microbial complex is dominated by the fungal component, on the Podkosmovo mire – by the bacterial component. This is the reason for the differences in the microbial biomass of the mires: 222 g/ m2 for the Podkosmovo, 898 g/m2 for the Bolsheberezovskoye mire. The reason for the differences in inundated mires is the range of variation in the level of mire waters during the growing season, due to the reclamation measures carried out in the Bolsheberezovskoye mire. Nevertheless, inundated mires are important “depots” of atmospheric carbon and the intensity of its accumulation is determined by a complex of factors.