image: China’s lake dissolved carbon storage spatial patterns during the 1990s (a), 2000s (d), and 2010s (g) and the change rate between 1990 and 2020 (j); China’s spatial reservoir dissolved carbon storage patterns during the 1990s (b), 2000s (e), and 2010s (h) and the change rate between 2006 and 2020 (j); China’s spatial river dissolved carbon flux patterns during the 1990s (c), 2000s (f), and 2010s (i) and the change rate between 1991 and 2018 (l).
Credit: ©Science China Press
This study was led by Professor Yang Gao and PhD candidate Shuoyue Wang from the Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences (CAS), Collaborators include Professor Gaboury Benoit and Professor Peter A. Raymond (Yale University, USA), Academician Guirui Yu (Institute of Geographic Sciences and Natural Resources Research, CAS), Professor Feng Zhou (Peking University), Associate Professor Shaoda Liu and Professor Chiyuan Miao (Beijing Normal University), among others. The researchers quantified changes in dissolved carbon storage in China's lakes and reservoirs and dissolved carbon fluxes in rivers over the past 30 years by integrating multi-source data including long-term field observation data from the research group, literature-collected data, and national water quality monitoring site data, combined with methods such as machine learning models and empirical models. It systematically revealed that climate change, anthropogenic disturbances, and water chemistry factors collectively drive the dynamics of dissolved carbon in inland waters.
The team found that dissolved carbon storage in China's lake water bodies increased from 84 Tg C to 115 Tg C over the past 30 years, with significant regional differences. Among them, the Northwest Rivers Basin and the Southeast Rivers Basin had the highest dissolved inorganic carbon (DIC) storage in lake water bodies, while the Northwest Rivers Basin, Songliao River Basin, and Yangtze River Basin had relatively higher dissolved organic carbon (DOC) storage in lake water bodies. Reservoir dissolved carbon storage doubled due to reservoir capacity expansion. The Yangtze River Basin and Pearl River Basin had the highest reservoir DIC storage, while the Southwest Rivers Basin had the highest reservoir DOC storage. The total dissolved carbon flux in China's natural rivers increased by only about 7% over the past 30 years, with significant spatial heterogeneity. The Yangtze River Basin, Southwest Rivers Basin, and Northwest Rivers Basin had the highest river DIC fluxes, while the Yangtze River Basin had the highest river DOC flux.
The researchers also found that carbon dynamics in China's inland waters over the past 30 years were synergistically driven by climatic factors (temperature and precipitation), anthropogenic factors (agricultural and urban land use), and water chemistry factors (water temperature, electrical conductivity, pH, total phosphorus, etc.). Among them, climate and anthropogenic disturbances mainly influenced river dissolved carbon flux changes by affecting hydrological connectivity and terrestrial carbon export, while water chemistry factors directly regulated dissolved carbon storage in lake and reservoir water bodies.
The research findings emphasize the critical role of inland waters in the global carbon balance and point out that under the background of global change, there is an urgent need to strengthen the accurate assessment of inland water carbon budgets to scientifically support carbon emission reduction policies and water quality management practices.
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See the article:
Dissolved carbon storage and flux dynamics in China’s inland waters over the past 30 years
https://doi.org/10.1093/nsr/nwaf229
Journal
National Science Review