Hotspots of Diffusive CO ₂ and CH ₄ Emission From Tropical Reservoirs Shift Through Time

The patterns of spatial and temporal variability in CO2 CH4 emission from reservoirs are still poorly studied, especially tropical regions where hydropower is growing. We performed spatially resolved measurements dissolved surface water concentrations their gas-exchange coefficients (k) to compute diffusive carbon flux four contrasting across Brazil during different hydrological seasons. used an online equilibration system measure concentrations; we estimated k floating chamber deployments conjunction with discrete concentration measurements. Diffusive emissions were higher dry season than rainy season, whereas there no consistent seasonal for emissions. Our results reveal that the magnitude within-reservoir varied strongly among River inflow areas often characterized by high seasonality flux. Areas close dam generally showed low but Overall, found reservoir exhibiting highest rates (“hotspots”) shifted substantially Estimates total surfaces differed between seasons a factor up 7 Chapéu D'Úvas, 13 Curuá-Una, 4 Furnas, 1.8 Funil, indicating need be at order constrain annual emission.