Abstract: Chenqiao East Lake is one of the perennial catchments in the middle experimental zone of Xinxiang Yellow River Wetland Bird National Nature Reserve, which is a breeding and habitat for many rare birds with important values for biodiversity conservation and potential scientific research and ecological tourism. To understand the plankton community structure and the water quality state in Chenqiao East Lake, we collected plankton samples in the studied lake in January (winter), April (spring), July (summer) and October (autumn) of 2017, and at the same time evaluated the water quality status by analyzing plankton diversity index. Results revealed a total of 118 species of phytoplankton belonging to 67 genera and 8 phylum, dominated by Chlorophyta (47 species) accounting for 39.83% of the total species, followed by diatoms (35 species), and Dinoflagellate of only two species. The abundance of phytoplankton varied from 2.52×10⁶ to 39.7×10⁶ cells/L. The main dominant species were Bacillariophyta, Chlorophyta and Cyanophyta. Moreover, we identified a total of 34 species of zooplankton, with primary dominance by Rotifer (21 species) taking up 61.76% of the total species. The abundance of zooplankton varied from 68 to 1 342 cells/L. The main dominant species was rotifer, while rotifers filter feeders (RF) was the main zooplankton functional group. The results of plankton diversity index showed that the water bodies in Chenqiao East Lake were moderately polluted, worst in summer and relatively good in winter, which was consistent with the investigation results of physical and chemical indexes of water bodies.

Key words: plankton, community structure, water quality evaluation, Xinxiang Yellow River Wetland, Chenqiao East Lake