Change of Organic Carbon Composition in Peat Profiles over the Permafrost Areas of Xinjiang Altai Mountains in China and Its Influence Mechanism
Permafrost peatland is one of the most important terrestrial carbon pools and plays a key role in regulating regional carbon cycle and local climate change.Most previous research concerned about the influence of regional climate change on the composition of peat organic carbon;however,little knowledge of the response of organic carbon stability to local environmental change was made.Permafrost peatlands in Xinjiang Altai Mountains is sensitive to climate change,and is one of the most important distribution areas of alpine peat in northwestern China.In this study,three peat profiles at Hehu,Halasazi and Sandaohaizi,separately located at three typical permafrost areas along Xinjiang Altai Mountains were selected for peatland survey.Fourier transform infrared spectroscopy(FTIR)technology was used to analyze the compositional changes of decomposable carbohydrate compounds as well as stable aromatic compounds in the peat profiles,for revealing the changes of organic carbon composition in the different local geo-environment circumstances.Physical and chemical indicators in the peat profile such as total organic carbon(TOC),humification degree(HD),ash content as well as local environmental conditions were jointly included in comprehensive analysis to describe the process of peat deposition and reveal the influence mechanism of the changes in peat organic carbon composition.(1)There were distinct differences in the organic carbon compositions in the peat profiles at the three survey sites of permafrost along Xinjiang Altai Mountains.At Hehu and Halazi,in the peat profiles it had a content of 26.63％and 26.58％aromatic compounds,separately,which was higher than that of 21.21％at Sandaohaizi.And it had a content of 36.12％carbohydrates compounds in the peat profiles at Sandaohaizi,higher than that of 21.84％at Hehu and 24.21％at Halasazi.(2)As for the ratio of aromatic compounds to carbohydrates compounds,the stability of organic carbon composition in the peat profile at Hehu was 1.33,higher than 1.14 at Halasazi and 0.60 at Sandaohaizi.The stability of organic carbon in the peat profiles at Hehu and Halasazi increased with depth,but at Sandaohaizi it decreased with depth.(3)The differences in vegetation population and microbial activity in permafrost peatlands under different environmental conditions along Xinjiang Altai Mountains were the main factors leading to the change of the stability of organic carbon.This study can provide references for scientific assessment of dynamic changes of organic carbon pool in alpine permafrost areas and its response to environmental changes.
万方数据
维普
