Abstract: To investigate the phosphorus (P) release characteristics and influencing factors of sediments from three different ecological types, black-odor river (BO-S), algal lakes (A-S) and macrophytic lakes (M-S), physical and chemical characterization, as well as release kinetics model were employed. In addition, the effects and mechanisms of anions (CO₃^2-, SO₄^2-, NO₃^-, HCO₃^- and Cl^-) and dissolved organic matter (fulvic acid and humic acid) on the P release characteristics of the three types of sediments were explored. The results show that the three types of sediments exhibited distinct different P release patterns. BO-S and A-S sediments primarily released soluble reactive P (SRP), accounting for 56.00% and 57.14% of the total release contents, respectively, while M-S sediments predominantly released dissolved organic P (DOP), which accounted for as much as 81.40% of the total release contents. Both anions and dissolved organic matter facilitated the release of P from sediments. Anions, particularly CO₃^2-, were the most effective in promoting the release of SRP. Compared to the control group, a concentration of 10 mmol·L^-1 of CO₃^2- led to an average increase of 39.2 times in the maximum release of SRP. Dissolved organic matter, particularly humic acid, mainly promoted the release of DOP. At a concentration of 100 mg·L^-1, humic acid caused an average increase of 56.3 times in the maximum release of DOP from sediments compared with the control group. Furthermore, the changes in the content of metal-bound P in sediments before and after P release indicated that anions and dissolved organic matter primarily promoted P release by competing for P adsorption sites on metal oxides.

Key words: sediment, physicochemical property, phosphorus, release, influencing factor