| In order to learn the phosphorus(P) species distribution in sediments of Lake Nansihu, 0-25 cm sediments from Weishanhu district in Lake Nansihu were analyzed with a sequential extraction method．The results show that: the average values of Ex-P, Al-P, Fe-P, Oc-P, Ca-P, De-P, Org-P in Weishanhu district sediments are 5.62 mg/kg, 4.08 mg/kg, 12.25 mg/kg, 13.34 mg/kg, 116.67 mg/kg, 232.36 mg/kg and 396.79 mg/kg respectively, and the rank order of P-fractionation for Lake Nansihu is Al-P＜Ex-P＜Fe-P＜Oc-P＜Ca-P＜De-P＜Org-P. The vertical phosphorous species distribution exhibits the obvious rule that exchangeable P(Ex-P), Fe-bound P(Fe-P), occluded P(Oc-P), organic P(Org-P) value decrease with depth, while the values of Al-bound P(Al-P), authigenic calcium bound P (ACa-P), detrital apatite P(De-P) increase. The Sum1 content (the sum of Ex-P, Al-P and Fe-P) in surficial sediments is remarkably positively correlated with the PO3-4 concentration of overlaying water, to which Fe-P content contributes the most with the correlation index 0.72. In spatial phosphorous species distribution, the discrepancy of potential active species(Ex-P, Al-P and Fe-P) is greater than those inert ones(Oc-P, Ca-P and De-P), and Org-P is only second to those potential active species. |
