Integrated human and natural regulation of carbon concentrations and fluxes dynamics in the Yangtze River mainstream over the past two decades.

Long-term data reveal that the Yangtze River's DOC flux increased while POC and DIC fluxes declined over two decades, driven by climate warming and reservoir construction.

• Why it matters: Understanding the dynamics of different carbon forms in large Asian rivers is crucial for global carbon cycle models and climate change predictions, yet such long-term, comprehensive assessments are scarce.
• What they did: A monthly database of DOC, POC, and DIC concentrations at 10 sites along the Yangtze River from 2000 to 2022 was compiled and analyzed using three machine learning algorithms to reconstruct continuous concentrations and derive fluxes based on discharge data.
• The result: The findings suggest a shift from a system dominated by POC and DIC export toward increased DOC export, impacting carbon burial and greenhouse gas emissions, with implications for regional carbon management strategies.