Taxonomical Study Of Diatoms From Sanjiang Plain Wetland,China

The Sanjiang Plain(N 43o49'-48o27 ',E 129o11'-135o05')located in the northeast of Heilongjiang Province,China.It belongs to temperate humid and semi-humid continental monsoon climate.The ecosystem of this region is diverse and has abundant algae resources.Samples were collect from the Anxing Wetland Nature Reserve(June 2010,October 2010,May and July 2011),Sanjiang Plain Wetland(Mumble River,Songhua River,Lianhua River,Qindeli,Linjiang,Bacha,Fuyuan,Hancongou,Naolihe Nature Reserve,Raohe County,Dongfanghong,Wulindong)(May 2011),Tongjiang,Fuyuan area(2012 June),Qixinghe Wetland and Fujin Wetland(August 2019).Totally,358 samples were collected and 716 perminent slides were made.Collection habitats include rivers,blisters,streams,lakes,swamps and reservoirs.Observations were carried out by using light microscope,the species biodiversity and distribution pattern of diatoms were studied.The results are as follows:1.According to the classification system of Round et al.(1990),230 taxa were identified,belonging to 3 classes,13 orders,28 families,58 genera,202 species and 28 varieties.For each taxon,detail taxonomical description,distribution habitats and LM pictures were provided.2.Three newly recorded taxa were observed in Sanjiang Plain wetlands.They are Ulnaria ulna var.aequalis(Kützing)Aboal,Craticula buderi(Hustedt)Lange-Bertalot and Neidium longiceps(Gregory)Ross.3.Among the diatom observed in this research.Coscinodiscophyceae has the fewest species,only 6 genera,9 species,2 varieties,a total of 11 taxa,accounting for 4.8% of the total number of species;Fragilariophyceae with 9 genera,29 species and 5 varieties,accounting for 14.5% of the total number of species;Bacillariophyceae has the most species,with 43 genera,164 species and 21 varieties,accounting for 80.4% of the total number of species.4.The number of common species of Sanjiang Plain wetlands is relatively rare.A total of 11 taxonomic units of dominant species were found,including Aulacoserira granulata var.angustissima O.Müller ? Aulacoserira granulata var.angustissima f.spiralis Hustedt?Fragilaria capucina var.amphicephala(Grunow)Lange-Bertalot?Cymbella cymbiformis Agardh?Cymbella excisa var.procera Krammer?Gomphonema sphaerophorum Ehrenberg ? Fallacia pygmaea(Kützing)Stickle & D.G.Mann ?Frustulia crassinervia Lange-Bertalot & Krammer ? Navicula rhynchotella LangeBertalot?Stauroneis amphicephala Kützing?Nitzschia reversa W.Smith.5.We compared the composition and distribution of diatoms at different sampling points and habitats.Diatom are abundant in Sanjiang Plain wetlands and the diversity is high at the genus level.A total of 58 genera have been observed.Pinnularia has the most species with 29 taxa,accounting for 12.6% of the total species.Gomphonema has 21 taxa,accounting for 9.13% of the total number of species;Eunotia has 16 taxa,accounting for 6.96% of the total number of types.Among all the sampling points,Naolihe Nature Reserve and Qixinghe Wetland has the most abudant diatom biodiversity,120 taxa and 103 taxa were observed respectively.Songhua River,Lianhua River,Bacha and Fujin Wetlands have very few taxa.Among the 6 habitats,most species are distributed in swamps and blisters with 199 taxa and 139 taxa respectively.Streams and rivers are next,with 86 taxa and 68 taxa respectively.Only 33 taxa were found from reservoirs.