Phosphorus distribution in lake sediments and interstitial water in different ecological function zones

For shallow lakes, phosphorus released from sediments becomes a major reason for eutrophication. To learn about the distribution characteristics of sedimentary phosphorous in Nansi Lake, China, the vertical distributions of sedimentary phosphorus at 5 representative sites were analyzed. The results showed that the sedimentary total phosphorus (TP) concentrations varied greatly, ranging from 313.50 to 963.48 mg·kg-1. As a typical macrophyte-dominated lake, organic phosphorus (Org-P) in Nansi Lake was the major phosphorus accounting for 41.56-52.60% of TP in sediment. Detrital apatite phosphorus (De-P) and authigenic calciumbound phosphorus (ACa-P) also represented a large proportion of TP in sediments, accounting for 14.77- 35.24% and 1.4-32.09% of TP, respectively. The vertical phosphorus distribution demonstrated a trend that Ex- P, Fe-P, Oc-P Org-P, and TP values decreased gradually with depth, Al-P and ACa-P decreased first and then increased with depth, and De-P had no obvious trend with depth. The results also indicated that the concentrations of PO43--P in interstitial water and the concentrations of Ex-P in sediments had a remarkable positive correlation.