Basin‐Scale CO₂ Emissions From the East River in South China: Importance of Small Rivers, Human Impacts and Monsoons

Abstract Riverine carbon dioxide (CO 2 ) emissions are an essential component of the riverine cycle, but accurate assessment CO emission fluxes is still hindered by spatial and temporal variations among river basins caused differences in climate, watershed characteristics, human activity. Here, we evaluate flux from subtropical East River Basin (ERB) south China, a region strongly affected monsoon climate anthropogenic land use changes. Our results suggest small rivers major contributors to emissions, even with relatively low concentrations water surface areas (SAs). They contribute disproportionately 74.4% total due high gas transfer velocity ( k across water‐air interface. Land changes have substantially enhanced networks. Normalized areal urban‐ cropland‐dominated Middle Lower ERB (27.6 39.4 g C m −2 yr −1 were two three times higher than 9.1 forest‐dominated Upper ERB. Due larger SA monsoon‐induced precipitation, acts as stronger source during wet season, emitting 0.67 Tg atmosphere, which about twice that dry season (0.33 ). study illustrated how regulated its emissions. findings also provided valuable insights into role basin‐wide cycle.