• • Temporal dynamics: Nutrient and Chl-a concentrations exhibited three phases: stable (Jan–Apr), fluctuating (May–Aug), and stabilizing (Sep–Dec), with peak timings varying by parameter, indicating seasonal biological and hydrological drivers.
• • Spatial heterogeneity: Overall south-high/north-low gradient, but NH4-N, TP, and Chl-a showed north-high/south-low reversals during specific periods, highlighting localized hydrodynamic and ecological influences.
• • External loading dominance: Dawen River inputs primarily controlled the overall distribution, while water temperature, dissolved oxygen, and hydrodynamics refined internal patterns; northern lake areas were particularly sensitive to hydrodynamic changes.
• • Nutrient fate divergence: Nitrogen was permanently removed via denitrification and anammox, whereas phosphorus remained in the lake through particulate transformation, leading to long-term retention and potential internal loading.