Influence of regional climate and local hydrological conditions on carbon accumulation process within the Jinchuan peatland (Northeast China) since the middle Holocene

Abstract

Peatlands represent a vital component of the terrestrial carbon pool owing to their high carbon sequestration efficiency. A comprehensive understanding of the carbon accumulation process and its driving factors is essential to assess future carbon reservoir functions. Within a single peatland, carbon accumulation may differ among sites because of local conditions. However, this spatial variability has received little attention. To address this gap, four peat cores from the Jinchuan (JC) peatland in the Changbai Mountains were analyzed to investigate the spatial heterogeneity and consistency of carbon accumulation since the middle Holocene. ¹⁴C Accelerator Mass Spectrometry was used to establish the chronological framework of each core, and the organic carbon content and bulk density were measured to calculate the carbon accumulation rate (CAR). The moisture conditions at each sampling location were reconstructed using the carbon stable isotopes (δ¹³C) values of α-cellulose in Carex spp. residues. The influence of both regional climate and local hydrological conditions on CAR was analyzed. The results indicated that the CAR values for the four cores were 62.9, 53.4, 44.2, and 47.7 g C/m²/yr, respectively. The moisture conditions across the sampling sites generally declined over millennial timescales, which is consistent with the decreasing regional precipitation in the Changbai Mountains. Between 6.5 and 1.5 kyr BP, the spatial heterogeneity in CAR demonstrated that local factors, such as topography and moisture conditions, were the dominant controls. Over the last 1.5 kyr BP, the consistent CAR values across the JC peatland indicated that the regional climate became the primary driver. This study demonstrates that hydrological variation is the key factor driving spatial heterogeneity in CAR and highlights that the dominant controls on CAR may shift over time. These findings can improve our understanding of climate-driven carbon accumulation in peatlands by integrating local environmental influences.