Oxygen-Loaded Porous Materials Inhibit Phosphorus Release at the Sediment-Water Interface in Eutrophic Waters

• • OLPM coverage reduced overlying water TP by 93.79% and reversed the SWI TP flux from +0.0068 to -0.014 mg/(m2·d), converting the sediment from a P source to a P sink, which is critical for achieving water quality targets in eutrophic lakes. • • Surface sediment DO increased 6.58-fold and penetration depth extended by 16.8 mm (1.33-fold), demonstrating effective oxygenation without sediment disturbance, a key advantage over mechanical aeration. • • Sediment P fractionation shifted towards stability: Res-P increased by 5.22% while labile NaHCO3-P decreased by 4.48%, indicating long-term P burial potential and reduced bioavailability. • • Fe2+ decreased by 59.62% and S2- distribution became uniformly low, confirming enhanced Fe oxidation and suppressed sulfate reduction, which are the dominant mechanisms for P immobilization at the SWI.