Study On The Distribution And Source Of Colloidal Material And CDOM Of Lake Taihu

As the third largest freshwater lake in China,Taihu lake is an important source of drinking water in the middle and lower reaches of the Yangtze River.Currently,eutrophication is a serious ecological environment problems in the taihu lake.In the process of algae blooms management,in-depth study on the bio-chemical cycle of biogenic elements is the basis for further work.According to previous studies,the structure of colloidal particles determines that the colloid has greater surface exchange adsorption capacity,so colloid plays an unique and indispensable role in the process of material circulation in the water ecosystem.In addition,CDOM is not only an important part of the warehouse of dissolved organic carbon,but also an important absorbing material of light and effective radiation in water,which can significantly change the structure of the underwater photic field and affect the water biochemical processes,carbon cycles,and eutrophication process of lakes.This paper takes Taihu Lake’s water as the research object,investigating and studying the colloidal substances and the distribution and source of CDOM in it.The conclusions are as follows: 1.The concentration of colloidal nutrients,DOC and CDOM in in-flowing rivers and lakes in the western region(Dapu river)is relatively high,and the concentration in eastern Xukou Bay and the middle of the lake is relatively low,appearing time and space distribution features with high concentrations of nutrients in summer and low in autumn and winter.And these types of colloidal substances are mainly imported into Taihu Lake through rivers.2.The contents of Cr,Cu and Zn,the colloid heavy metal elements,are higher in the channel,and the contents of Cd and Pb in the Taihu lake area are higher.Cr and Cu,the common heavy metal elements,are mainly imported from Chenqiao Brook to Taihu Lake,and Zn is mainly from Dapu River to Taihu Lake area.3.Overall CDOM concentration: Western Taihu Lake Area> Zhushan Bay> Meiliang Bay> Gonghu Bay> middle of the Lake> Eastern Taihu Lake area.The fluorescence intensity in the west of Taihu Lake differs greatly,and it’s relatively small in the east of Taihu lake.The CDOM in the lake’s bay tend to decrease towards the outside of the bay.The Lake’s water showed strong peak of protein-like.Except for the strong peak of humic-like in the northwestern area of lakes including Zhushan Bay and Dapu Estuary,the peak of humic-like in other areas was weak,indicating that most water in the Taihu Lake was composed of protein components CDOM.4.Indoor degradation experiments proved that the degradation of phytoplankton and submerged plants could release a large amount of organic matter and inorganic nutrients.Bio-degradation input large amounts of CDOM in the water in the first two weeks,indicating that biodegradation is one of the important sources of CDOM in lake.