EVALUATION AND DRIVING CHARACTERISTICS OF WATER NUTRIENTS IN POYANG LAKE BASED ON TLI METHOD
As the largest freshwater lake in China,Poyang Lake has important ecological functions and social values.According to the monitoring data of Poyang Lake from 2012 to 2017,six representative monitoring points in the lake were selected in this study.The trophic status of the lake was evaluated by the Trophic level index method(TLI),and the correlation coefficient method was also used to.judge its accuracy based on the bioindicators.The regression equation of Poyang Lake trophic was proposed,and the hydrological characteristics of the lake were included in the calculation,and biological indicators were introduced as reference.The findings were as follows:1)according to the evaluation result of the TLI method,the average value of TLI in Poyang Lake was within the range of 44.00 to 49.00 during the time period of the study,which means that Poyang Lake was mostly in the medium-rich trophic level.Banghu Lake,shaped like a disc,was in the eutrophic state in 30.56％of the study time,and was at a high trophic level.2)compared with the seasonal pattern of higher algal cell density in summer and lower algal cell density in winter,the TLI values in Poyang Lake remained stable,with a standard deviation in a range of 3.00 to 5.00.The TLI value could not match the significant difference in algal cell density in the lake,and the TLI value only changed by about 2％in the case of a 300％difference in algal cell density.The reason is that the water physicochemical indicators(TP,TN,SD,COD)in the lake do not well reflect the algal proliferation status,while the TLI method is highly dependent on these indicators.3)the drivers of algal proliferation in Poyang Lake were highly spatially heterogeneous,among which water temperature had a high positive effect on algal proliferation,and total phosphorus was one of the limiting factors for algal proliferation at monitoring point of Hukou,Banghu,and Kanshan.In contrast,flow volume and water body transparency had different effects at different points due to spatial variability in lake basin morphology.To achieve effective management and protection of lake water,other factors need to be taken into account to achieve a comprehensive master of the mechanisms driving algal proliferation.
Poyang LakeTLI methodeutrophicationbiological indicatorshydrological characteristicsregression model
NETL
NSTL
万方数据
