Study On The Biological Mechanism Of Phosphorus Release From Sediments In The Shallow Lakes

Shallow lake eutrophication is a serious problem in our country. Furthermore, the study on phosphorus action in the interface of sediment-water is one of the key elements, which helps find the mechanism of eutrophication. Due to shallow water, nutrient matters transport and processes were frequent and complex. The mechanisms of shallow lakes eutrophication were also complex. Biological process between water-sediment interfaces ploy a very important role in the all kinds of transport and processes of nutrient matters, so the three-dimension model based on the two-dimension between water-sediment were put forward. Overlying water, sediment and biological dimension become the future emphasis of research subjects. This paper was supported by nation basic research program "Studies on the Process of Eutrophication of Lakes and the Mechanism of the Blooming of Blue Green Alga" (2002CB412304). The mechanism of phosphorus release and transform were study on biochemical viewpoint adopting local observation and the laboratory simulation. Biology and related enzymological methods were applied to the research of the circulation and metabolism of phosphorus in water-sediment. Without external contamination, the influences of the behavior of phosphorus in sediment for biological dimension were discussed under different environmental condition. The main findings are as following:(1) Concentrations of total phosphorus (TP), their fractions and the bio-available phosphorus (BAP) in the surface sediments from three different regions of Taihu Lake are investigated. In addition, the potential release capacity of P from the surface sediment and their sources were discussed. The concentrations of TP, P fractions and BAP are coincided very well with their trophic states. The concentrations of organic P in the sediments have a good relationship with organic matter and moisture content. BAP is mainly from Fe bound P (Fe-P) and Ca bound P (Ca-P), which show the highest potential risk of release.(2) Effects of algal to phosphorus exchange on water-sediment decide the quantity of available phosphorus in overlying. This influence algal growth reversely. Microcystis aeruginosa can evidently improve the quantity of phosphorus release from sterilized sediments, and increase the concentration of dissoluble inorganic phosphate (DIP) in overlying. But Selenastram bibrainum Reinsch restrains phosphorus release from sterilized sediments. The concentrations of DIP were kept in a low level all through which result in the quantity of Selenastram bibrainum Reinsch decrease because of nutriment restriction. Therefore the ability of using nutriment for algal may be the...