Carbon dynamics of peatlands in China during the Holocene

Abstract

Understanding the responses of the carbon-rich peatland ecosystems to past climate change is crucial for predicting peat carbon fate in the future. Here we presented a data synthesis of peatland initiation ages, area changes, and peat carbon (C) accumulation rate variations in China since the Holocene, along with total C pool estimates. The data showed different controls of peatland expansion and C accumulation in different regions. The peat C accumulation rates were 32.3 (ranging from 20.7 to 50.2) g C m−2 yr−1 in the Qinghai-Tibetan Plateau (QTP) and 14.7 (ranging from 7.4 to 36.5) g C m−2 yr−1 in the Northeast China (NEC). The peaks of peatland expansion and C accumulation in the QTP occurred in the early Holocene in response to high summer insolation and strong summer-winter climate seasonality. The rapid peatland expansion and maximum C accumulation rate in the NEC occurred in the middle-late Holocene. Peatlands scattered in the coastal and lakeside regions of China expanded rapidly at the onset of the Holocene due to large transgression, consistent with the stronger summer insolation and monsoon, and during the middle and late Holocene, as a response to the high and stable sea level and the strong summer monsoon. The carbon storage of peatlands in China was estimated as 2.17 (ranging from 1.16 to 3.18) Pg, among which 1.49 (ranging from 0.58 to 2.40) Pg was contributed by peatlands in the QTP, 0.21 (ranging from 0.11 to 0.31) Pg by those in the NEC, and 0.47 Pg by those scattered in other regions of China. Our comparison of peatlands dynamics among regions in China showed that climate and monsoon are the essential factors in determining the expansion and carbon accumulation patterns of peatlands, although their effects on peatland formation and C accumulation is complex owing to land availability in peatland basins and regional moisture conditions.