| Daqing Longfeng Wetland Nature Conservation Area located in the hinterland of Songnen plain, is one of the provincial class conservation in the urban areas in Heilongjiang Province, China. It covers5050.39hm2and lies between125°07’125°15’E and46°28’-46°32’N,8km away from the city, and which was rare in the middle of the city in China.Algae assemblages were investigated at five sampling sites in Longfeng wetland from May to October of2011and May to August2010. Physical and chemical indicators of water were also monitored during the same period at the sampling sites The composition of algal species and cell density in different sampling sites were examined. The diversity of their community structures were analyzed by diversity index. The relationship between environmental factors and algal diversity were analyzed by the CCA analysis and BIOENV analysis. On this basis, the water quality of the wetland was evaluated in Longfeng wetland. The main results are as follows:1. During the survey period, A total of439algae taxa including413species25varieties and1form were identified in Longfeng Wetland belonging to8Phylum,11Class,24Order,51Family,122genus. The greatest percentages of taxa were recorded in the Chlorophyta (209spp.) and Bacillariophta (85spp.) followed by Euglenophyta (73spp.), Cyanophyta(50spp.), Pyrrophyta (8spp.), Cryptophyta (4spp.), Xanthophta (7spp.), Chrysophyta (3spp.). The result of the quantitative analysis revealed that the total average cell density of the algae was17.27×105cells/L. In comparison with other algae, Bacillariophyta was the dominant, followed by Chlorophyta and Cryptophyta also dominant in some sites.2. Most of the dominant species and common species in the study area of Longfeng Wetland was pollution indicator species such as Scenedesmus dimorphus (Turp.) Kutzing、Nitzschia palea (Kiitzing) W. Smith、Cyclotella meneghiniana Kutzing、 Ankistrodesmus angustus B ernard、Euglena viridis Ehrenberg.3. At the same time, the physical and chemical indicators in each sampling site were monitored. The analysis results shows that the water was Weak alkaline that pH was7.18-8.88; the water temperature was12.6-28.4℃; the water conductivity(SpCond) was563-2430μS/CM; the dissolved oxygen (DO) was1.3-7.3mg/L; the chemical oxygen demand (CODcr) was27-107mg/L; Potassium permanganate index(CODmn) was8.31-35.94mg/L; the biological oxygen demand (BOD) was7.07-36.4mg/L; the total phosphorus(TP) was0.92-2.19mg/L; the total nitrogen concentration (TN) was0.75-13.8mg/L. the water nutritional level was mesotrophic. TLI evaluation showed that the water nutrition level of Longfeng wetland was mesosaprobic.4. Margalef index, Shannon-Wieaver index, Pielou index, Simpson index and Diversity threshold index were comprehensively used in the assessment of algae. R values ranged from1.45to6.44; H values ranged from1.49to3.84; J values ranged from0.37to0.870; D values range from0.50to0.97; Dv values range from2.94to4.53. The Comprehensive Evaluation of the results showed that water nutrition in the study area ranges oligotrophic to mesotrophic.5. The algal relative abundance and environment variables were examined by canonical correspondence analysis (CCA). Among sampling stations different physical and chemical indicators impact the algal community structure. The distributions were discussed in different months. The result of CCA indicated that WT and water conductivity were important environmental variables affecting algal community structure of the Longfeng wetland. pH, CODcr, TN were also make affect on algal community structure.6. BIOENV analysis was used between environmental factors and algal community in different sampling sites by PRIMER5.0in order to find out the group of environment factors which make the largest affect on algal. There has some different between two years. The results show that pH、WT and CODcr were important environmental variables affecting algal community structure of the Longfeng wetland... |
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