Temporal And Spatial Distribution Characteristics And Analysis On Influence Factor Of Phytoplankton In The Way Of Route System Of Cascade Reservoirs

According to the water environment monitoring data from May 2013 to June 2014 at three Series of reservoirs(A,B,C)on the routes in southern china,determine the composition of planktonic algae species,the advantage of algae in different seasons,t-he typical pollution indicating algae,and freshwater potentially harmful algae.Through investigation the physical and chemical factors of water(Water depth,tra-nsparency,water temperature,pH,turbidity,dissolved oxygen,total nitrogen, total phosphorus) in the way of route system of cascade reservoirs and combined with the monitoring data of planktonic algae,to explore the temporal and spatial distribution characteristics of phytoplankton cell density and the community structure from the perspective of biological and environmental,identification of sensitive season,sensitive algae,s-ensitive layer,sensitive area and the key influencer.At the same time to explore the vertical distribution characteristics of phytoplankton in the surface(A layer),the depth of the euphotic layer(B layer) and the bottom o-f the water layer(C layer).To explore the differences of reservoir water quality through the analysis the difference of phytoplankton biodiversity index.Analysis on corelationship between phytoplankton cell density and environmental influence factors by correlation analysis.The research results show that:(1)7 plyla,105 genera of planktonic were identified from the cascade reservoirs,including cyanophyta,chlorophyta,bacillariophyta,other phytoplankton:23,48,25,9 genera.Chlorophyta is the most abundant planktonic algae species composition o-f c-ascade reservoirs groups,the following is bacillariophyta,cyanophyta,other phytoplankton species is less.Cascade reservoirs were detected the 38 pollution indicator species and classified as 5 types of nutrient and 14 species of freshwater potentially harm-ful algae.(2)Blue-diatoms are dominant species phytoplankton of cascade reservoirs.It is obvious of dominant species in seasonal variation.Cyanobacteria are advantage alage i-n addition to the winter(In december and January) diatom became the dominant alage.The characteristics of the chlorophyta are many types and the less number.(3)The cascade reservoir on the layers of phytoplankton follow the same variation trend.In the summer of July is sensitive season of cyanobacteria bloom,Sensitive algae as pseudoanabaena,lyngbya,raphidiopsis.in the winter of January is sensitive season of bacillariophyta,Sensitive algae as melosira,skeletonema.(4)There are three types of distribution in vertical direction of the phytoplankton cell density:1)A layer>B layer>Clayer 2) B layer>A layer>C layer 3) C layer>A/B layer.the A layer is sensitive layer of phytoplankton.(5)In the way of route system of cascade reservoirs,the phytoplankton cell density along a straight line up.The average diversity index decreased,and the water q-uality gradual deterioration.intake of C reservoir(S7#) is sensitiveregion of planktonic algae.(6)The key factors affecting the growth of cyanobacteria is the water temperature, pH,turbidity,total phosphorus, nitrogen/phosphorus ratio(TN:TP),the key factor t-o affect the growth of diatoms is the temperature,the key factor growth of Chlorophyta is pH,nitrogen/phosphorus ratio(TN:TP).