Peatland initiation and carbon accumulation in China over the last 50,000 years

Abstract

Peatlands are one of the largest biosphere carbon (C) reservoirs. Understanding the responses of these C-rich ecosystems to past climate change will provide useful insights into projecting the fate of peatland C in the future. Here we present a data synthesis of peatland basal ages and C accumulation rates in China over the last 50ka (1ka=1000calyr BP) and provide a conceptual framework for understanding the dominant controls of wetland dynamics. China's peatlands are distributed throughout the climate domain from −5°C to 18°C in mean annual temperature and from 200 to 1600mm in mean annual precipitation. Peatland basal dates show that subtropical peatlands initiated more frequently during the Marine Isotope Stage 3 (MIS 3) than in the Holocene, while northern peatlands mostly initiated in the early and mid Holocene. Peat-core data from peatlands in northern China show high apparent rates of C accumulation (30–40gCm−2yr−1) during the early and mid Holocene. The peatland initiation and C accumulation histories are closely linked with summer insolation and monsoon intensities, suggesting the possible causal connection between peatland dynamics and Asian summer monsoon. Furthermore, peatland formation and expansion in the subtropical region of China, especially during the MIS 3 and the Bølling–Allerød periods, might have contributed to high atmospheric methane concentrations.