Zooplankton Community Structure Characteristics in Longtan Reservoir of Hongshuihe River
红水河龙滩水库浮游动物群落结构特征

In summer and winter of 2009, 137 species of 73 genera zooplanktons have been observed in Longtan Reservoir. It is 100 species in summer with 10 dominant species and 108 species in winter with 11 dominant species; and 6 dominant species are observed both in summer and winter. The mean density of zooplanktons is 5800ind./L, protozoa dominating; average biomass is 1.2366mg/L with rotifers amounting to the most part. Zooplankton standing crop in summer and winter is with no significant difference, while the horizontal distributions both in summer and winter are with significant differences. From the density-based clustering analysis on them, zooplanktons in sections of Longtan Reservoir are classified into 3 groups. Since the reservoir was constructed, zooplankton standing crop in the flowing sections at the tail of the reservoir has changed slightly, while significant increases have taken place in the head and middle of the reservoir. According to ecological indicators for zooplankton, the water quality of Logntan Reservoir belongs to mesotrophic-oligotrophic type.