Environmental release of phosphorus and nitrogen in the surface sediments of Dianchi Lake, China

In this study, the total mass of phosphorus (P) and nitrogen (N) were calculated by the method of Thiessen Polygons in water and pore water of surface sediments of Dianchi Lake in 2010 and 2011, and the increments were used to reflecte the really environmental release status during this period. The results showed that the sediments of Dianchi Lake were still as a sink for P until 2010, which was different from other researches of Dianchi Lake. The major circulating form was dissolved total phosphorus (DTP) in water-sediments interface, especially was the PO43-. However, the content of N in the sediments of Dianchi had reached saturation and the sediments were as a source of N before 2010, while the release trend of N from sediments became slow gradually.