Remote sensing retrieval and driving factors of dissolved organic carbon concentration in typical lakes of the middle Yangtze River in China from 2000 to 2023

Dissolved organic carbon (DOC) is the largest organic carbon (C) pool in aquatic systems and closely related to lake C emissions. However, long-term monitoring of DOC dynamics and their driving factors remains limited. This study analyzed DOC concentration evolution in five typical lakes of the middle Yangtze River from 2000 to 2023 using remote sensing retrievals, Mann-Kendall trend test, Pearson correlation, and multiple general linear model (GLM). The results showed that (1) The retrieval models performed well, with R 2 values of 0.76, 0.74, 0.80, 0.84, and 0.76 for Daye, Bao'an, Wanghu, Xiandao, and Cihu lakes, respectively. (2) From 2000 to 2023, the DOC concentrations increased by 1.16 and 3.57 mg/L per decade in Daye and Bao'an lakes, respectively; decreased by 1.38 and 4.00 mg/L per decade in Xiandao and Cihu lakes, respectively; but remained relatively stable in Wanghu Lake. (3) The DOC concentration was highest in summer for most lakes, although the decomposition of submerged vegetation litter led to relatively higher DOC concentrations in spring in some years in Bao'an and Xiandao. (4) GLM analysis identified cultivated land, the normalized difference vegetation index, and population as the most significant watershed-scale drivers. These findings underscore the need for non-point source pollution control in this basin. The results of this study provide a new strategy for the large-scale monitoring of DOC concentrations in lake water, which is helpful for providing a deeper understanding of the lake C cycle and aiding lake ecological restoration and management.