[Cycling characteristics of phosphorus in an urban lake and its eutrophication potentiality].

Input and output pathway, fluxes, characteristics and temperature-increasing responses of phosphorus cycling in the East Lake located at the centre of Linhai City, Zhejiang Province, China were analyzed. On the basis of the annual field observation on the lake, it was indicated that chlorophyll a in water was being increased at the average rate of 0.14-0.56 microg/L, the transparence in water was being decreased at the average rate of 0.38-0.49 m, and dissolved oxygen in water was being reduced at the average rate of 0.21-0.71 mg/L. Relationships between the representative measurable parameters which can reflect the eutrophication potentiality of a lake and total phosphorus (TP) in water were set up, thus revealing that a change of phosphorus in lake water can be used to comprehensively judge the nutrition situation of a lake through forecasting changes in other factors and their relationships. This work can thus provide a scientific basis for decreasing eutrophication and improving water quality of lakes.