Study On Eutrophication Mechanisms Of Dongting Lake And The Mutlianalysis Between Chlorophyll A And Other Impact Factors Of Water Environment

In recent years, due to the rapid development of industrialization, urbanization,livestock and poultry breeding well as improper use of chemical fertilizer, manylakes water quality deterioration and eutrophication trend is obvious. As one of thefive largest fresh water lake dongting lake, are also facing the same problem.Dongting lake is a bearing na xiang, endowment, yuan and li four HongDao typewater and throughput of the Yangtze river water lakes, communication plays ashipping, breeding aquatic products, and improve the ecological environment, andother functions, in hunan province and the Yangtze river water system of ecologyand economy plays a very important position. To grasp the dongting lake waterquality eutrophication mechanism, analytical dongting lake spatiotemporaldistribution of nitrogen and phosphorus pollution and chlorophyll a, affected by thewater quality factor of multiple effects. This topic in dongting lake of eight sectionsas the research object, between January2012to December, month by month ofdongting lake river hydrology, physical chemistry, and the ecological index of fieldinvestigation and monitoring. At the same time, combined with years of waterquality monitoring data of dongting lake stations offer, dongting lake water qualityeutrophication mechanism are analyzed, and the nutrient such as nitrogen,phosphorus and chlorophyll a space-time change rule are analyzed, and further to thechlorophyll a and the other influence factors of water quality in the multipleregression analysis, to dongting lake environmental protection and management toprovide scientific and reasonable basis. The main research conclusions are as follows:the spatial distribution characteristics of chlorophyll a of east dongting lakeconcentrations of chlorophyll a mean of3.0μ g/L, and west dongting lake and southdongting lake is only1.3μg/L, in between the three lakes there is an obviousphenomenon of east dongting lake is higher than that of west dongting lake andsouth dongting lake chlorophyll a and total nitrogen is very significant positivecorrelation, while chlorophyll a and total phosphorus and nitrogen and phosphorusratio, no obvious correlation between. Dongting lake eutrophication index of averageof42, the lake eutrophication level is relatively stable, nutrient levels in82%of thetime in all the year round. Chlorophyll a and impact factors of the multivariateanalysis results show that the water quality of west dongting lake chlorophyll a andthe water temperature has significantly positive correlation, and show verysignificant positive correlation between total nitrogen; South dongting lake ofchlorophyll a were very significant positive correlation with the water temperature, negatively related with transparency, were very significant positive correlation withtotal nitrogen; East dongting lake of chlorophyll a were very significant positivecorrelation with the water temperature, and were very significant negativecorrelation between transparency, present significantly positive correlation with totalnitrogen. Within the scope of the dongting lake all, chlorophyll a were verysignificant positive correlation with the water temperature, and showed a significantnegative correlation between transparency and present significantly positivecorrelation with total nitrogen. Further the exponential correlation analysis by lg(YChl. a) and lg (XTN) has very significant positive correlation, and lg (XTP) and lg(XTN/TP) no significant correlation; On the basis of linear equation is: the lg (YChl. a)=1.069+0.349lg (XTN), is this equation fitting, more guiding significance in practice.