Coprecipitation of Organic Matter, Phosphate With Iron: Implications for Internal Loadings of Phosphorus in Algae-Dominated and Macrophyte-Dominated Lakes

Coprecipitation with iron (Fe) plays an essential role in the biogeochemical cycles of organic carbon (OC) and phosphorus (P) lakes. The sources composition matter (OM) mediate its association iron, which could thus influence immobilization phosphorus. In this study, water-soluble from sediments two typical states shallow lakes, macrophyte-dominated zones (M-WSOM) algae-dominated (A-WSOM), was extracted, ternary coprecipitation WSOM, phosphate Fe(III), investigated. process enhanced increasing Fe(III) or decreasing pH value. It found that 6.5 more favorable for than a 7.5 8.5. At 6.5, complexation between WSOM occurred at low inputs, while phosphate, took place when inputs reached 40 μM. presence A-WSOM showed stronger inhibition on by M-WSOM. formed coprecipitates had lower C/Fe ratios (0.13–2.78) those M-WSOM (1.28–4.05), because aromaticity addition, functional groups complex resulting less OC P during A-WSOM, Fe(III). Our results demonstrated zones, remained soluble coprecipitation, perform positive feedback growth phytoplankton provide novel explanation difficulty restoring eutrophic