Species of phosphorus in surface sediments from the sea area of Hangu in Tianjin

Species,contents and bioavailability of phosphorus in surface sediments from the sea area of Hangu in Tianjin were investigated using a sequential phosphorus extraction method.The results showed that the total phosphorus in the surface sediments were 525.68×10-6～688.39×10-6 and were dominated by inorganic phosphorus which on average accounted for 86.98% of total phosphorus.Among the species of inorganic phosphorus,detrital phosphorus was its dominant form which on average occupied 59.54% of total phosphorus.It was also found that bioavailable phosphorus in sediments mainly included loosely adsorbed phosphorus,Fe-bound phosphorus and organic phosphorus.Bioavailable phosphorus at the study area varied from 465.87 10-6 to 609.79×10-6,accounting for 89.14% of the sedimentary phosphorus pool.This observation reflected that sediments from the sea area of Hangu had a strong ability of release phosphorus into the pelagic water.