[Forms and distributions of particulate phosphorus in the surface sediments of North Yellow Sea]

Surface sediments were collected from the North Yellow Sea in October 2007. The sediments were analyzed with modified SEDEX to obtain six forms of phosphorus. The results indicate that among the total phosphorus the detrital phosphorus and authigenic phosphorus are the main forms and the content varies from 25.7 to 122.5 microg x g(-1) and from 5.7 to 176.2 microg x g(-1), respectively, which taking up 17.0% -56.9% and 10.2% -49.8% of the total phosphorus. The content of exchangeable phosphorus, extractable organic phosphorus, iron-bound phosphorus and refractory phosphorus ranges from 5.5 to 43.9, from 4.1 to 41.4, from 2.3 to 26.7, from 6.0 to 33.6 microg x g(-1), respectively. Detrital and authigenic phosphorus are the major forms of the total phosphorus, indicating that the natural input is the major source of particle phosphorus in the study area. The content of iron-bound phosphorus is low, indicating that human input is minor in the area; mass fraction of the extractable organic phosphorus and refractory organic phosphorus is low, indicating that there is a low organic content while the main form of the total phosphorus is inorganic in the surface sediments of this area. Bioavailable phosphorus as exchangeable phosphorus, extractable organic phosphorus and iron-bound phosphorus account for 6.7% - 33.2% of the total particle phosphorus, indicating that bioavailability of phosphorus in the surface sediments is low.