Spatial differences in Holocene peat and carbon accumulation rates in three peatlands in the permafrost region of Altai Mountains, Northwestern China

Abstract

Peatlands in northern permafrost regions contain large carbon pools that are sensitive to regional and global factors. Considerable uncertainty remains about the potential impacts of global climate change on the processes important to peat C accumulation, especially in permafrost regions. In this study, peat cores from three different peatlands in the permafrost region in Xinjiang Altai Mountains of northwestern China were investigated to explore their peat properties and carbon accumulation histories. The results show that peat initiation ages, peat properties and carbon accumulation rates differed in the three different localities, caused by differences in topography, local climate, and permafrost changes. Moreover, we find that unlike the variations of Holocene C accumulations in non-permafrost peatlands, Holocene mean peat carbon accumulation rate (CAR, mean 35.5 ± 10.7 (SD) g C/m²/yr) in the permafrost region is higher than Holocene CAR values (mean 25.4 ± 7.7 (SD) g C/m²/yr) in non-permafrost peatlands, and had higher CARs before 6.5 cal. Kyr BP with continuous decreases from 6.5 to 2.0 cal. Kyr BP, and higher values during the late Holocene. Although these variations are like other northern peatlands, they share different driving mechanisms in long-term peat carbon accumulation. We postulate that under the background of continuous warming related to increasing 50°N winter solar radiation, changes in vegetation type associated with permafrost thawing have had a central role in determining long-term peat and carbon accumulation rates in the permafrost regions in the Altai Mountains.