Lake ecoregions and nutrient criteria development in China

China has numerous lakes that have suffered water quality deterioration and decreasing area. Based on climatic, geographic, and ecosystem differences, this study scientifically proposes that national lake ecoregions provide a spatial basis for nutrient criteria development in China. Moreover, ecoregional nutrient criteria were established to support policies for national eutrophication control. China was divided into eight separate lake ecoregions, and the differences in nutrient effects for different lake ecoregions were analyzed. National nutrient criteria were developed for seven lake ecoregions using the stressors-responses models. Due to local variations in water chemistry and lake depth, the range of nutrient criteria exhibited significant differences within certain nutrient ecoregions. The establishment of ecoregional nutrient criteria will provide technical support and implement water quality standards, thereby avoiding the under-protection of lakes in China. To reduce future lake eutrophication, China needs an ecoregional control strategy that integrates measures to comply with regional water quality standards.