Bacterial communities in cascade reservoirs along a large river

Dam construction is widespread, changing the hydrological and biogeochemical conditions thereby bacterial communities in rivers of earth. To date, knowledge lacking about cascade reservoirs. Here, we investigated potential functions nine hydropower reservoirs 1290 km upper Mekong River (Lancang China). Along reservoir cascade, water temperature, rather than presence dams, was main cause for geographical patterns community composition. Within a reservoir, significant spatial differences sediment were observed between tail, middle, head reservoir. The properties resulted by flow velocity-sieved sedimentation from tail to caused variation bacteria communities, forming hotspots cycling middle In contrast, unlike deep lakes single reservoirs, bacterioplankton composition had no distinctly layered features because density-induced underwater currents convection resulting production reduced vertical hydro-environmental gradients. This study provides novel perspective on processes affecting distribution function river-reservoir cascades, first step toward forecasting consequences microbially mediated existing future worldwide.