Quantification of lake carbon accumulation and sequestration in China since the Last Glacial Maximum

English Abstract:

Understanding the responses of lake systems to past climate change and human activities are critical for assessing and predicting the fate of lake carbon (C) in the future. Here we synthesized the lake C storage from 82 lake sediment records throughout China and analyzed the controlling factors over their long-term mass and carbon accumulation in the last 20 ka (1 ka = 1000 cal yr BP). Our results show that mass accumulation rate (MAR) and carbon accumulation rate (CAR) are highly variable through time and in different regions, as a result of regional climate and environmental histories as well as human activities. The lake CAR (4.05-16.21 g C m^-2 yr^-1) over the last 10 ka was higher than those (CAR: 2.2-13.3 g C m^-2 yr^-1) at 20-11 ka. We estimated the total amount of C burial in lakes of China as about 9.3 Pg, with 2/3 of this being accumulated in the last 10 ka. About 71% of this C stock is stored in lake abundant regions, including the Tibetan Plateau, Southeast China region. Our synthesis suggests that both climate and human activities have significant influence on lake mass and carbon accumulation in China. This first estimation of C dynamics and total storage of lakes in China confirms the importance of lakes in terrestrial C budget in monsoon-influenced regions.