Abstract

The carbon cycle constitutes one of the major occurring material cycles, with a large influence on human development and global climate change. This paper reviews recent research on dissolved inorganic carbon (DIC) in the Jialing River basin, Wujiang River basin, Chishui River basin, and Xijiang River basin. It provides a comprehensive analysis from a regional perspective on the spatiotemporal distribution, influencing factors, and sources of DIC and carbon isotopes (δ13CDIC) in the water bodies of the southwestern karst region. The conclusions are as follows: (1) There were variations in DIC concentration and δ13CDIC values among the different water systems, with notable spatiotemporal distribution. The Chishui River basin exhibited the highest DIC concentration (2.79 mmol/L) and δ13 CDIC value (-8.15‰), while the Xijiang River basin had the lowest DIC concentration (1.95 mmol/L) and δ13CDIC value (-10.6‰). (2) DIC concentration changes in the region were influenced by a combination of factors, including carbonate rock chemical weathering, climate change, and human activities. (3) DIC in the watershed is primarily derived from carbonate rock weathering and soil CO2. These research results contribute to advancing the study of DIC variations in river basins and provide a theoretical foundation for carbon cycling in water bodies in China.