The Research Of The Phosphorus Forms In The Sediment And Exchange Of Nutrients Between The Sediment-water Interface In Bohai Bay

This paper applied JENSEN etc (1998), A six- steps sequential chemical extraction methods to analyze the samples which were collected from Bohai in November 2003 and May 2004,at the same time, A laboratory incubation experiments was used to study the exchange of nutrients between the sediment and water interface at A21 station sample colleted in MAY 2004, the result show:1. Physical chemical property of sediments, the level of nutrients of sediments and environment of geography were correlated. The total situation is the more fine of sediments the more high level of nutrients; the more near the shore the more seriously polluted; the more far the shore the more lightly polluted. The grain size distribution in Bohai sediment was that fine sand and arenaceous powder sand dominated tideland to clayey powder sand dominated Bohai Bay.2. The phosphorus of Bohai Bay surface sediments presented enlarging situation from the tidesand to Bohai Bay, the inorganic phosphorus (IP) was the major phosphorus species of total phosphorus (TP) in the sediment, organic phosphorus (OP) has highly positive correlation with TP, it showed close relation between them.3. Through analysis of phosphorus forms, the contents of various phosphorus (P) was positively correlated with the different environment, with the different environment the contents of phosphorus forms was different. Detrital apatite (FAP) and refractory organic phosphorus (Ref) were main components among the six phosphorus forms in Bohai Bay sediments .FAP accounted for 43 percent among six phosphorus forms, the average content was 56 percent, Ref accounted for 24 percent ,the average content was 37 percent, followed leachable organic phosphorus by the average content accounted for 5 percent, then iron- bound inorganic phosphorus(Fe-P) , authigenic apatite (CFAP), loosely adsorbed inorganic phosphorus, the contents of these three kinds of phosphorus forms all accounted for under 10 percent. It showed that the main sources of phosphorus in Bohai sediments were land input and sewage drainage.4. From the third conclusion it could know that there was more than half ofsedimentary phosphorus pool in the Bohai Bay was not used by biology.5. At the A21 station of Bohai Bay, the exchange of NO3-N was the main part among those of total inorganic nitrogen, under the without any added condition, the exchange of NO3- N accounted for 99% among the exchange of TIN; under the aerated air condition the exchange of NO3- N accounted for 64% ;under the aerated nitrogen condition, the exchange of NO3- N accounted for 84%; under the added mercury chloride(HgCl2)three condition, the exchange of NO3- N all accounted for over 50%.6. The biological activity had a great influence on the exchange of nutrients at the sediment-water interface. Biological activity made the flux of PO43"- P and NO3-N decrease at A21 station in Bohai Bay; the flux of NO2-N a little increase; compared with contrast situation, changed the exchange direction of NH4- N , the flux of NH4- N also increased.7. Under situation of aerated air the exchange of NO3- N and NO2- N at sediment- water interface was benefit, the poor oxygen repressed their exchange. Poor oxygen benefited to the exchange of NH4- N, under situation of aerated air it disadvantaged the exchange of NH4- N.