Study of Chemical Forms of Phosphorus and Their Distributions in the Surface Sediment in Zhejiang Offshore

Total phosphorus and its related forms in the surface sediment in Zhejiang offshore were studied by SEDEX method.The results showed that the content of total phosphorus(TP) in the surface sediment was 432.2-846.1 mg/kg,and average content was(533.2±90.1) mg/kg,and the average content of weakly absorbed phosphorus(Ads-P),iron phosphorus(Fe-P) calcium phosphorus(Ca-P),detritus phosphorus(De-P) and organic phosphorus(OP) were 6.2,93.2,12.4,295.0 and 66.5 mg/kg,respectively,and the percentage composition of TP were 1.2%,17.7%,2.4%,56.7% and 12.7%,respectively.The content of different forms of phosphorus in different sites was mainly influenced by terrigenous inputs,sediment grain size and hydro-dynamics.There are significant positive correlations between sediment grain size,organic carbon and Ads-P,Ca-P,OP;and negative correlations between sediment grain size,organic carbon and De-P.