A Preliminary Study On Algae(Except Bacillariophyta) In Harbin Section Of Songhua River

Songhua River is the third largest river in China,located in the north central part of Northeast China,Songhua River is the largest tributary of Heilongjiang in China.Harbin section of Songhua River is located in the middle reaches of Songhua River and flows through Harbin city,with a total length of 70 km.The main tributaries are Lalin River,Ashi River,Hulan River,etc.The region has a north temperate monsoon climate with various ecological types and abundant algae resources.In this study,samples were collected from 6 sampling areas of main stream,Hulan River of Songhua River,Larin River,Ashi River,Majiagou and Hejiagou in Harbin section of Songhua River in Harbin section of Songhua River from April to October in 2019 according to the sampling time of spring,summer and autumn.A total of 363 algae samples were collected.A taxonomic study of the algae(except Bacillariophyta)was carried out by using a light microscope(ZEISS Imager.A2),The main results are as follows:1.In this study,296 taxa of algae(except Bacillariophyta)are observed,belonging to 271 species,23 varieties and 2 forms of 89 genera,33 families,17 orders,9 classes,7phylum were identified.Among them,21 species belonging to 20 genera of Cyanophyta,1 species belonging to 1 genus of Chrysophyta,4 species belonging to 3 genera of Xanthophyta,2 species belonging to 1 genus of Cryptophyta,6 species belonging to 3genera of Pyrrophyta,53 species belonging to 8 genera of Euglenophyta,10 varieties and2 forms,149 species and 13 forms belonging to 53 genera of Chlorophyta.The morphological description of each taxon is given in detail.The distribution and habitat information of each taxon are given,and the clear light microscope photos are attached.A total of 105 photos are attached.2.Snowella litoralis(H?yrén)Komárek & Hindák was named as a new record in China.It belongs to Chroococcaceae,Chroococcales,Cyanophyta.3.The species composition and ecological distribution characteristics of algae(except Bacillariophyta)in Harbin section of Songhua River are analyzed.The results are as follows:(1)The algae(except Bacillariophyta)in Harbin section of Songhua River are rich in biodiversity,with many species but few in quantity.The main species are freshwater common species.(2)Among the seven phylum,Chlorophyta has the most species,and Chlorellaceae and scenedesmaceae are the main species,while Chrysophyta has the least species.(3)Among the 296 taxa,there are more rare species,and the dominant species are few,obvious,and most of them are common species.In the observed specimens,only 6species become more obvious dominant species.At the same time,there are typical light pollution medium pollution indicator species.(4)In this study,the main habitat is river,and there are few samples of wetland and lake,so the number of river species accounts for the majority,and most of them are planktonic species,and the species in each habitat accounts for about 13% of the total species.The main stream of Songhua River has the highest diversity of algae species.Ashi River,Majiagou River and Hejiagou River are seriously polluted and have more pollution tolerant species.Majiagou River and Hejiagou River have the lowest diversity of algae species,accounting for about 12% of the total species.(5)In the three seasons of 2019,autumn is the most abundant with 258 taxa,followed by summer with 214 taxa and spring with 99 taxa.Species appearing in all three seasons accounts for 31% of all the taxa.