Distribution of Phosphorus and Nitrogen in the Sediments of the North Bay in Dianchi Lake

Phosphorus and nitrogen fractions of four core sediment samples collected from the north bay of Dianchi Lake in China were analyzed. The condition of various forms of phosphorus and nitrogen varied with sediment depth among different sites, and characters of vertical distribution are discussed. Large amounts of phosphorus and nitrogen were accumulated in sediments of the shallow and estuary. The contents of phosphorus in the sediments were relatively stable over a period of time, and the variation trend of reductant soluble phosphorus showed high vertical and spatial variations, which were related to the redox state of sediments. Vertical distribution of nitrogen and fractions presented complex change tendency and there were no obvious similarities of the variation trend among all sites. Average concentrations of phosphorus decreased with the distance of the estuary in the whole profile. Results reflected that the phosphorus and nitrogen load was aggravated with time of estuary of Panlong River in recent years. Mineralization and sedimentary rates of organic matter in all sediment sites were multiple in different periods and the complicated variability of sedimentary environment exerted influence on the formation process in different sites.