Macrobenthos Community Structure And Biological Evaluational Research Of Water Quality In Songhua River Along Harbin City

The wetland is one of most important and multi-functional ecosystems on the earth, known as "kidney of the earth". The ecological study of zoobenthos was conducted on seven typical sampling sections selected in Songhua River along Harbin city, in spring, summer, and autumn in 2008. Zoobenthos communities and biodiversity were examined with multivariate statistic analysis. The gray association analysis was used to detect the correlation between zoobenthos and environmental factors. The water quality in Songhua River along Harbin city was assessed by physical and chemical indicators and biological diversity index. The purpose of this paper was to provide a guideline of management and a foundation for the future study in Songhua River wetland.Total of 60 species were identified, among which, the majority are aquatic insects (39), accounting for 65 percent; followed by molluscs,13 species, accounting for 21.67%; seven kinds of annelid, accounting for 11.67%; one crustacean species, accounting for 1.67%.The total mean abundance and biomass were 1277.286ind./m2 and 102.2346g./m2. There was big change in species number, abundance and biomass between season and sampling stations by ANOVA. The temporal and spatial distribution of abundance and biomass were spring> autumn> summer, the spatial variation for the upstream and downstream is higher than the middle reaches, such differences associated with environmental factors in the distribution.There were different ranges in different diversity index, Shannon-Wiener index throughout the year between 0.227-1.461, the highest in spring, to 1.461, the lowest in autumn, to 0.227;Margalef index throughout the year between 1.18-1.81, the maximum value appears in the summer, to 1.44, the minimum value appears in the spring, to 1.18; Simpson Biology index throughout the year between 1.375-2.539, the maximum value appears in the summer, to 1.375, the lowest in the fall, to 0.61;Goodnight-whitely amendment index throughout the year between 0.293-0.512, the maximum value appears in the spring, as 0.512, the lowest value appears in the summer, for the 0.293. Shannon-Wiener index trends are spring> summer> autumn; Margalef index is the summer> autumn> spring; Simpson Biology Index summer> spring> autumn; Goodnight-whitely amended index is spring> autumn> summer.The hierarchical cluster analysis revealed that the zoobenthos community structure in Songhua River along Harbin city was classed three groups, the comparability is high within groups and the great change between groups. The results of nor-matric multi-dimentional scaling (MDS) was basically the same of the hierarchical cluster analysis, was classed four groups, and showed the change was for the change of hydrographic factor and vegetation.The correlation between density and biomass in spring, summer and autumn with various environmental factors is different, the results showing the impact of the various environmental factors on zoobenthos communities.The result of grey relational analysis suggested that the greatest impact on the density for the total nitrogen, the greatest impact on biomass for ammonia in Spring; the greatest impact on the density of chemical oxygen demand, the greatest impact on biomass for biochemical oxygen demand in summer; the greatest impact on the density for the ammonia nitrogen, the greatest impact on biomass for total phosphorus in fall. The factor which seriously influenced zoobenthos was nutrient factor. The results of the physical and chemical evaluation and biological evaluation are in agreement, evaluation results show that water quality in the Songhua River in Harbin in the moderate to severe polluted state.