The carbon dynamic and driving mechanisms of peatland in the Changbaishan volcanic field of China

The Changbaishan volcanic field ranks as one of China's largest active volcanic fields. Numerous peatlands developed in this area, serving as crucial carbon sink within the country. In this well-known volcanic field, climatic changes and volcanic eruptions are likely to have exerted a notable impact on the carbon accumulation processes of peatlands. That said, the specific carbon dynamics in these peatlands and the possible driving mechanisms remain insufficiently understood. To address these unresolved questions, this study chose the Dongfanghongnan peatland as research subject. Findings from the investigations indicate that this particular peatland began to store carbon during the Late Holocene epoch. From 4344 to 1000 cal. yr BP, temperature and precipitation functioned as major factors that regulating carbon dynamics of the Dongfanghongnan peatland. Nevertheless, since 1000 cal. yr BP up to now, tephra deposition has been the major affecting factor for the carbon dynamics of peatlands. Furthermore, two distinct types of high-efficiency carbon sequestration patterns can be distinguished in the Dongfanghongnan peatland. The first pattern is named the climate-nutrient type. In an environment with increased rainfall and intense solar radiation, higher temperature may boost the productivity of Carex . At the same time, moist conditions are beneficial for the conservation of peat, which in turn helps trap carbon. In addition, nutrient phosphorus was transported into peatland with a phosphorus accumulation rate (PAR) of 0.058 g P m −2 yr −1 , raising the net primary productivity of plants growing in the peatland. These combined effects led to a high-efficiency apparent carbon accumulation rate (aCAR), reaching 21.88 g C m −2 yr −1 . The second pattern is referred to as the tephra fertilization type. Tephra released a large amount of phosphorus (with a PAR of 0.071 g P m −2 yr −1 ). Abundant phosphorus supply promoted the net primary productivity of both Carex and mosses. This promotion eventually resulted in a high-efficiency aCAR, which was measured at 24.90 g C m −2 yr −1 . These findings deepen understanding of the relationship between climate variations, volcanic activities, and carbon sequestration of peatlands. They also establish important basis for making forecasts about the future carbon dynamics of peatlands in Northeast Asia. • Tephra deposition influences the carbon sequestration of peatlands. • Carbon dynamics of peatlands was related to climatic changes. • Phosphorus from tephra promoted high carbon sequestration of peatlands. • The influences of temperature on peatlands have a threshold. • The influences of precipitation on peatlands have a threshold.