| Hulan River wetland is located at the nothshore of Songhua River, Hulan District, Harbin, China.N45°5′4″-45°51′48″,E126°38′29″-127°14′22″. As one of the key restoration wetlands in Harbin. Hulanhe wetland has an excellent natural wetland ecosystems with rich fauna and flora.Algae assemblages were investigated at eight sampling sites in Hulanhe wetland from May to October of 2009 and 2010. 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 cluster analysis. On this basis, the water quality of the wetland was evaluated and the basic information was provided to assist in the restoration and protection of Hulanhe wetland.The main results are as follows:1. During the survey period , a total of 216 algae were found in the study area of Hulanhe wetland,belonging to 7 phyla, 8 classes, 14 orders, 23 families and 50 genera. These include, Bacillariophyta with 23 genera, 92 species and 6 varieties and Chlorophyta with 15 genera, 52 species and 5 varieties. Others include, Euglenophyta with 5 genera and 39 species; Cyanophyta with 5 genera and 17species; Dinophyta with just 1 genus and 2 species, Xanthophyta also has 1 genus and 1 species while Cryptophyta has 1 genus as well and 2 species. The result of the quantitative analysis revealed that the total average cell density of the algae was 2.35×107ind/L. In comparison with other algae, Bacillariophyta was the dominant, followed by Chlorophyta and then Euglenophyta.2. In comparison with the community structure of algae in different sampling sites, the character of the algae distribution from the sites in Hulanhe wetland was provided with more taxa and more abundance. The dominant species in the study area are Cyclotella meneghiniana, Melosira granulate, Navicula cryptotenella and Euglena acus. Euglena viridis, Oscillatoria tenuis wre found to be responsible for eutrophication.3. At the same time, the physical and chemical indicators in each sampling site were monitored. The analysis results shows that the pH was more stable, the dissolved oxygen (DO) was 4.15-16.38mg/L, the chemical oxygen demand (COD) was 17.6-20.88mg/L, the biological oxygen demand (BOD) was 1.93-2.6mg/L, the total phosphorus(TP) was 0.06-0.14mg/L, the total nitrogen concentration (TN) was 2.86-4.18mg/L, the water conductivity(SpCond) was 175-509μS/CM and the water nutritional level was mesotrophic.4. Margalef index, Shannon-Wieaver index, Pielou index, Simpson index and Diversity threshold index were comprehensively used in the assessment of algae. H 'values ranged from 1.504 to 3.390; H values ranged from 1.876 to 2.460; J values ranged from 0.537 to 0.640; D values range from 0.904 to 0.914; DV values average was 3.31. The Comprehensive Evaluation of the results showed that water nutrition in the study area ranges oligotrophic to mesotrophic.5. The algal individual 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 seasons. The result of CCA indicated that DO, WT, TN and TP were important environmental variables affecting algal community structure of the Hulanhe wetland.6. Environmental factors in different sampling sites were cluster analysis and multi-dimensional analysis of MDS by PRIMER5.0. The results show that there were certain similarities among samplingⅡ,ⅣandⅥ. The community structure and the physical and chemical indicators were similar in samplingⅢandⅦ. Due to the geographical location, there were great similarities between samplingⅠandⅠ. But samplingⅧdid not show remarkable similarities with others. This result was obtained with the standard determination of physical and chemical indicators of water and the algal distribution.7. The quality of water was evaluated by biological index and trophic state index assessment. The result showed that the great majority of algae belong toα- mesosaprobic zone andβ-mesosaprobic zone indicators while a few belong to oligosaprobic zone indicators. TSI evaluation showed that the water nutrition level of Hulanhe wetland was mesosaprobic. |
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