Organic carbon burial and quasi-periodic environmental changes in the Indian summer monsoon region during the Holocene

Abstract

Abstract Organic carbon (OC) burial in lacustrine sediments represents an important sink in the global carbon cycle. However, limited knowledge is available on the spatial-temporal variation and driving factors in OC burial of lake sediment during the Holocene. Based on the environmental proxies, grain-size end-member modelling analysis (EMMA) and wavelet transform of the Fuxian Lake sediments, the key factors of the organic carbon accumulation rate (OCAR) and the driving mechanism of climate in the Indian summer monsoon (ISM) region have been discussed during the Holocene. The results show that there was significant correlation between the environmental proxies and the OCAR, and 1000-a, 500-a and 100-a quasi-periodic signals were present in the environment proxies. The ISM intensified with an increase in low-latitude solar insolation (LSI) during the early- to mid-Holocene. It brought the warm-humid climate, the increased biological productivity and the OC input of the lake catchment. Therefore, climate change was the primary influencing factor on OCAR at this stage. In the late-Holocene, the weakening LSI and frequent human activities of the Fuxian Lake catchment caused a decrease in vegetation coverage and an increase in soil erosion, and it indicated that the intense human activities and climate change had to work together to affect the OCAR of the lake catchment. The results would provide some references for predicting the carbon sequestration potential of a lake under the influence of climate change and human activities, and it can also provide theory guidance for controlling carbon storage of lake ecosystem under global warming.