Climate change-induced water quality alterations in Poyang Lake: implications for the Yangtze finless porpoise

Climate change and anthropogenic activities are intricately linked, significantly impacting water quality in freshwater ecosystems like Poyang Lake, which is crucial for the survival of the critically endangered Yangtze finless porpoise (Neophocaena asiaeorientalis). This study examines the synergistic impacts of these stressors on water quality dynamics and their implications for porpoise conservation from 2012 to 2020 which reveal significant seasonal hydrological fluctuations, with summer precipitation peaking at 288.67 mm and evaporation rates reaching 406.3 mm in 2020, intensifying ecological instability. Nutrient pollution emerged as a critical threat, with total nitrogen (TN) and total phosphorus (TP) concentrations escalating to 4.95 mg/L and 0.106 mg/L, respectively, indicating heightened eutrophication risks driven by agricultural runoff and urbanization. Strong correlations between TN and TP (r = 0.289–0.472) highlight interconnected pollution pathways, while trace element bioaccumulation in porpoise tissues notably arsenic in blubber (0.8 mg/kg) and cadmium in kidneys (1.0 mg/kg) exceeded marine mammal toxicity thresholds, posing significant health risks. These findings underscore how climate-altered hydrology exacerbates contaminant mobilization, creating compound stressors for this endangered cetacean. We propose integrated strategies for nutrient reduction creating thermal refuge and pollution controls to support Sustainable Development Goals (SDGs). This multidisciplinary framework advances freshwater ecosystem resilience in an era of concurrent climatic and anthropogenic pressures, offering actionable insights for global biodiversity conservation.