Species and Characteristics of Organic Phosphorus in Surface Sediments of Northwest Region of Taihu Lake, Eastern China

Various organic phosphorus species in surface sediments from the northwest area of Taihu Lake, China, were measured using organic phosphorus fractionation scheme and the relationships among total organic carbon and different phosphorus species including total phosphorus (TP), total inorganic phosphorus, total organic phosphorus (TOP), microbial biomass P (Biomass-Po), fulvic-associated P (FA-Po), humic-associated P (HA-Po), and residual P were also investigated. The results showed that large amounts of phosphorus were associated by organic matter. Organic phosphorus was the important phosphorus species and accounted for 20-50% of TP. TOP, HA-Po, and Biomass-Po concentrations decreased from the northwest to southeast region of the lake on the whole. HA-Po accounting for 34-46% of TOP displayed an unstable trend and was easier to be transformed to other phosphorus species. FA-Po was relatively stable and did not directly contribute to internal loading of phosphorus. Significant and positive correlation between HA-Po and other species indicated that HA-Po and Biomass-Po were easier to transform to inorganic phosphorus which could be ingested by aquatic organism directly and responsible for high primary productivity of northwest of Taihu Lake.