Forms and distribution of phosphorus in sediments of Dianshan Lake
淀山湖沉积物磷分布特征

Based on filed sampling work conducted in August 2010, phosphorus forms and distribution in the sediments of Dianshan Lake were analyzed. The results showed that the content of total phosphorus and phosphorus fractions varied significantly in different regions. The TP contents ranged from 266 to1146 mg·kg-1 with the maximum values in the north sampling sites. The spatial distribution of TP in surface sediment tended to decrease from the northwest to the southeast region. The rank of phosphorus fractions was HCl-P> NaOH-P >OP>Ex-P in terms of the average concentration. Ex-P existed in minor quantities,accounting for less than 1% of TP. OP changed dramatically in different regions, and the concentrations in deeper layers were higher than those on the surface. HCl-P was the major phosphorus fraction in the east lake region. Similar to TP, the proportions of NaOH-P were higher in the northwest lake region. There was a significant positive correlation between TP and NaOH-P in the sediments of the Dianshan Lake (r=0.820). It was suggested that eutrophication in the north and northwest regions of Dianshan Lake was more serious than other regions, and most proportion of the TP was from anthropogenic sources.