Correlation Analysis of Water Quality and Aquatic Communities in Dawangtan Reservoir, China

With Dawangtan (DWT) Reservoir as the object, this paper explores the composition and diversity of the fish, phytoplankton and zooplankton communities, the current state of water quality in the reservoir with signal indices, and the trophic level index (TLI) method and the correlation between water quality and aquatic communities in the reservoir discussed using Spearman's rank correlation coefficient. The research results show that the 2,625 fish samples observed belong to 34 species, 26 genera, nine families and four orders. Phytoplankton samples taken belong to 43 genera, 25 families and seven phyla. Chlorophyta, Bacillariophyta and Cyanophyta had more genera than the other phyla. The Shannon Wiener diversity index (H') of phytoplankton was 2.24. Zooplankton samples belong to 23 genera, 16 families and four classes, most of which are small zooplanktons like Protozoa and Rotifera. The H' value of zooplankton was averaged at 2.29. Carlson's TLI indicates that the water in DWT Reservoir is mesotrophic, but the water quality is close to being slightly polluted. The water quality conforms to the Grade III standard in GB3838- 2002. The correlation analysis shows that in DWT Reservoir, the number of fish species and that of fish individuals are both positively correlated with the biomasses of phytoplankton and zooplankton, which, in turn, have significant correlations with water quality indices.