Study On Correlation Between Phytoplankton Community And Water Environmental Factors In Changshou Lake

Changshou lake was a artificial freshwater lake which was formed after Shizitan Hydropower Station dam was built during the first Five-Year Plan,developing into a water body with multiple functions of drinking,irrigation,tourism,culture and powergeneration A study about temporal and spatial succession of phytoplankton community and water environmental factors,relationship between phytoplankton community and water environmental factors was performed from March,2013 to February,2014 in Changshou Lake.The results of the study are as follows:?1?A total of 7 phylums,55 genera,84 species of phytoplankton were identified during the whole year investigation,Chlorophyta,Bacillariophyta and Cyanophyta were the main phylums.There was no significant difference in time and space.The density of phytoplankton varied in the range of 0.15²1.86×107 cell/L,Spring and summer are much higher than autumn and winter,the northwest of the lake area is much higher than the central and eastern,The phytoplankton community structure was of Cyanophyta-Cryptophyta type in spring,of Cyanophyta type in summer,of Chlorophyta-Cryptophyta type in autumn,and of Bacillariophyta-Cyanophyta in Winter?2?The phytoplankton dominant species during the whole sampling period were Limnothrix sp.,Komma caudate,Cryptomonas erosa,Cryptomonas marssonii,Stephanodiscus hantzschii,Merismopedia sp.,Lyngbya sp.,Raphidiopsis sp.,Ankistrodesmus angustus,and Chlamydomonas incerta.Dominant species had obvious seasonal and spatial succession.?3?The annual variation range of Margalef index?d?,Shannon-Weaver index?H'?and Pielou index?J?were 1.08².00,2.03³.95 and 0.39⁰.76.For seasonal changes,each index showed that autumn and winter was higher than spring and summer.Margalef index?d?in the northwest region was higher than central and eastern region;Shannon-Weaver diversity index?H'?and Pielou index?J?in the northwest and central region were higher than eastern region.?4?During the investigation period,the functional group Y was the representative functional group in the spring,autumn and winter.The functional group S1 is a typical functional group in spring and summer.The dominant functional groups in spring,summer,autumn and winter were S1 and Y,SN and S1,Y and J,and Y and D,for spatial changes,In spring,the dominant functional groups transform from northwest Y to East and middle MP and S1;in summer,northwest change from D and LO into S1 and SN in the middle and east;in autumn,northwest Y change into central J and become the eastern Y;northwest Y and D to S1 and D in central and Eastern Y and X2 in winter.?5?There were significant seasonal differences?P<0.05?of WT,light intensity,ORP,DO,CODMn,SD,TN,TP andNH₄⁺-N,and there was a significant difference?P<0.05?of each sampling site's EC,pH,SD,TN,TP,DOC,turbidity.?6?By the method of comprehensive nutrition index,the nutritional status of Changshou Lake was changed from moderate eutrophication in spring to mild eutrophication in summer and mesotrophy in autumn and winter.?7?SPSS correlation analysis showed that chlorophyll a was significant correlated with DO,pH,SD and WT;the dominant phytoplankton species succession was correlated withNH₄⁺-N,EC,SD and illumination;Margalef index?d?was correlated with NH₄⁺-N,WT,ORP,pH,EC and turbidity,Shannon-Weaver index?H'?was correlated with pH,WT,DO and SD,Pielou index?J?was correlated with pH,WT,DO and SD.?8?The results of RDA analysis showed that the succession of phytoplankton functional groups was significantly correlated with EC,SD,DO,TN,WT and illumination.