Unravelling phosphorus adsorption characteristics and release potential in estuarine sediment under runoff regulation

Endogenous phosphorus (P) release and its complex biogeochemical transformation pose ongoing challenges for effective P management in estuarine ecosystems. However, the understanding of how these processes respond to runoff regulations remains rarely constrained. This study investigated the spatiotemporal distribution of P forms in bottom water and sediment of the Liao River Estuary under anthropogenic runoff regulations characterized by low runoff in summer and normal runoff in winter. The sediment P adsorption capacity and release potential were studied through adsorption kinetics and thermodynamic experiments. Soluble reactive P (SRP) and total dissolved P (TDP) concentrations in bottom water were low in summer but increased markedly in winter (p