An ecosystem-oriented framework reveals coupled climate and human controls on river water quality

River water quality, governed by complex natural and anthropogenic drivers and further intensified by global climate change, poses growing threat to aquatic ecosystems and human water use. To systematically disentangle drivers in controlling river water quality, an ecosystem-oriented framework that bridged and included diverse catchment attributes  (e.g., climate, topography, lithology, land cover, and human influence) was proposed and tested against monthly data from 149 catchments in the Yellow River Basin (YRB). The framework addressing the vegetation and soil mediated mechanisms achieved satisfactory performance and reiterated the dominant role of human influence as primary source controlling water quality. Legacy effects of topographical and lithological controls, which shaped present-day soil, vegetation, and geomorphological characteristics by regulating long-term energy and material fluxes, led to great positive effect of aspect and a negative effect of pb (basic plutonics rocks) proportion on concentrations of water quality metrics represented by organic pollution indicators (BOD5, COD, and permanganate index) and nitrogen and phosphorus loads (ammonia nitrogen, total nitrogen, and total phosphorus). Within the ecosystem-oriented framework, vegetation and soil exerted opposite mediating effects on climate-water quality relationships, partially offsetting each other. Moreover, direct effects of warming-wetting climate positively influenced the concentrations of organic pollution indicators, while negatively affected nitrogen and phosphorus loads. The proposed framework clarifies the relative roles of diverse catchment attributes and offers a transferable basis for anticipating future water quality trajectories under ongoing climate change, supporting tailored river water quality management.