The distribution of phosphorus forms and its environmental significance in the marine ranching. demonstration area of Haizhou Bay sediment

The chemical speciation of phosphorus as well as its bioavailability of the marine ranching demonstration area of Haizhou Bay sediment was investigated by the grading methods for inorganic phosphorus in combination with the determination of the overlying water primary productivity. The results showed that the content of TP in summer was significantly higher than the spring and autumn, Inorganic phosphorus(IP) was the most abundant form, which accounted for 45.50% of TP. Content of inorganic phosphorus fractions in the surface sediment followed the order: residual inorganic phosphorus(Re-P)calcium bound phosphorus(Ca-P)Fe and Al-bound phosphorus((Fe+Al)-P)exchangeable phosphorus(Ex-P). Ex-P,(Fe+Al)-P and Ca-P had positive correlation with organic carbon content(P0.01, R0.8). Phosphorus content in surface sediments decreased from inshore to open sea of Haizhou Bay. This trend can be mainly attributed to the effects of terrigenous input and the sediment texture. The potentially biological available phosphorus(BAP) accounted for a large proportion(36.95%) of TP.