Cascading River-Lake Hydrological Regulation Reshapes Carbon Budgets of Floodplain Lakes in the Yangtze River Basin

Floodplain lakes are key components of the global carbon cycle and highly sensitive to human activities like cascade hydrological regulation. Using machine learning coupled with hydrodynamic models, this study evaluates the impacts of the Three Gorges Dam (TGD) and proposed lake-specific hydraulic projects (LHPs) on carbon budgets in the floodplain lakes of the Yangtze River Basin. TGD operations increased CO2and CH4emissions from Dongting Lake, raising its the globalwarming potential (GWP), but reduced emissions from Poyang Lake, lowering its GWP. LHPs operation will increase carbon emissions from both lakes, intensifying the greenhouse effect—especially in Poyang Lake. Overall, cascadeoperation of TGD and LHPswill increase floodplain lakes’carbon emissions. Our findings can support adaptive management and ecological restoration under intensified global change.