Studied On The Community Structure Of Alage In Harbin Section Of Songhua River

Songhua river is a very important water system in Heilongjiang Province, this river originate from Tianchi lake, Changbai Mountain e. The upstream is called ”second white river” and the downstream is called “Nenjiang river”.It inflows in Heilongjiang river near the Tongjiang river. The watershed of Songhua river is nearly 53.33 hm2.Both sides ofthis river is low-lying plains.Harbin is the biggest city of Songhua watershed, the winter here is long and cold, the freezing time here is 5 to 6 months. Because of the high rainfall, flood disaster happenedfrom middle of July to August 2013. The algae communities must be disturbed by the flood strongly, but until now, few reports were published about the algae in Songhua river.Algae assemblages were investigated in Harbin section of Songhua River and five sampling sites were selected, samples were collected from July to October of 2013 and June to October of 2014. Physical and chemical parameters were also measured during the same periodThe algae community, cell density and dominant taxa were investigated. Diversity index was also used to analysis the algae diversity structure in the area. The Cluster analysis and MDS analysis were used in grouping sampling sites for studying the similarity between algae community composition in different sampling sites. EDDI was used to validation the physical and chemical factors is right or wrong.CCA was used to analysis the relationship between the algae community structure and the environmental factors. The results are as follows:1.During the survey period, 150 taxa were identified which were belonging to 7 divisions, 9 calsses, 19 orders, 30 families and 63 genera in Harbin section of Songhua river. Species of Chlorophyta were most abundant with 58 taxa, Bacilllariophta with45 taxa, Euglenophya and Cyanophyta, 14 taxa were observed respectively,, 14 Pyrrophyta and Xanthophta,only 2 taxa were identified separately and Chrysophyta only 1 taxa were found.2. The distribution of the dominant algae in different time and space were compared. The dominant species were Chlorella vulgaris Beijerinck?Kitchneriella obesa(W.West) Schmidle?Melosira granulata(Ehr.) Ralfs?Cyclotella meneghiniana Kützing and Synedra ulna(Nitzsch) Ehr. The water is clean and human activities are less between site 1 and site 2.The dominant species were Synedra acus Kützing?Dinobryon sp.?Micractinium pusillum Frasenius. Site 3 and 3 ??had serious pollution, the dominant species were Trachelomonas spinulosa(Skv.) Defl. and Euglena acus Ehrenberg. The water in site 5 is very clean and the dominant species are Dinobryon sp.?Stephanodiscus minutulus and Stephanodiscus neoastraea H?kansson et Hickel.3.With determination of the physical and chemical factors in Harbin section of Songhua River, algae of there were giving priority to tobasophilic and a large number of algae were like phosphorus and nitrogen and medium-strong electrolyte. Because of the study area has a certain water pollution and the water nutrition level was mesosaprobic.4.Margalef index(H), Pielou index(J), Simpon index(D), Shannon-Wiener index(H') and Threshold value of diversity(Dv) were used to analyse the distribution of algae in time and space, EDDI was used to prove the accuracy of the numerical of pH and TP. H values were ranged from 0.73 to 2.27, J values were ranged from 0.21 to 0.80, D values were ranged from 0.66 to 0.94, H' values were ranged from 1.8 to 3.05, Dv values were ranged from 4.14 to 7.94. TP and p H real values were ranged from 7.21 to 7.996 and TP values were ranged from 0.1 to 0.21(mg/L). But these values were calculated from 6.35 to 8.01 and 0.05 to 0.27 respectively. The water nutrition level was mesosaprobic in the study area.5.To explore the relationship between the dominant species and environmental parameters, the CCA index analysis was operated. The relationship between algae and physical and chemical parameters in different months, seasons and years were analyzes th In 2013, WT(P=0.004),SpCond.(P=0.038) and TP(P=0.026) are the most motivate factors. In 2014, WT(P=0.008) and pH(P=0.029) were the most motivate factors.6. PREMER 5.0 were used to cluster and do MDS analysis of algae from all sampling sites. The results showed, the algae communities were similar in S1 and S2,. In the picture of MDS, the location of S3 and S4 are closer, But S5 was isolated from others. MDS stress is less than 0.2 means cluster analysis and MDS analysis are matched to each other and explain the relationship of algae communities among different sites.