Carbon Accumulation in Peatlands of the Mordovian Nature Reserve During the Holocene

The results of the study of the Holocene carbon accumulation in four peatlands of different genesis and landscape position in the area of Smidovich Mordovian State Nature Reserve, located on the southern border of the coniferous-broadleaved forests of the East European Plain, are presented. The analysis of the carbon content in the peat deposits showed that in the mineratrophic peat dominated by remains of peat-forming vascular plants, the Corg content is 46.9‒60.9% (the average is 54.6%) and these values are generally higher than the Corg content in transitional woody-Eriophorum-Sphagnum and Eriophorum-Sphagnum peats, 43.6‒50.1% (the average is 47.8%). Low values of Corg (39.2%) are found for grass and woody-grass highly inundated and weakly decomposed peat in a karst bog. The carbon accumulation rate in the peatlands ranges from 5.2 to 84.9 g C/m2 per year, with an average value for the entire Holocene of 22.5 g C/m2 per year. The analysis of the distribution of carbon accumulation rate (CAR) in the peat deposits by depth and age has shown similar patterns of carbon deposition in the four peatlands studied: an increase in CAR during the period of 10 500‒7500 cal. yr BP (calendar years before present) and a decrease in the intensity of carbon accumulation during the period of 7500‒3500 cal. yr BP, which partly coincides with the Holocene Thermal Maximum, when the climate was warmer and drier than at present. The formation of the upper horizons of the peat deposits of the bogs and the carbon accumulation during the late Holocene showed individual specific features in different peatlands, with a general trend of CAR growth.