Ecological study on meso-zooplankton and micro-zooplankton in the Pearl River Estuary in summer

Species composition,dominant species,community structure,diversity and abundance of meso-zooplankton and micro-zooplankton were examined based on data obtained from 18 stations in August 2009 in the Pearl River Estuary.A total of 120 species of zooplankton and 5 groups of planktonic larva were collected.The average of zooplankton abundance was 4 131.92 ind/m3 during the survey period.The dominant species were represented by Acartiella sinensis,Evadna tergestina and Penilia avirosstris.The species composition,abundance and dominant species of zooplankton showed distinct spatial heterogeneity in the estuary.The fluctuations in species richness,abundance and community structure were mainly determined by the freshwater inflow and the ecological feature of the zooplankton itself in summer.The cluster analysis classified the samples into two groups.One represented estuarine group and the other was neritic group.,Salinity was the main factor in determining the significant spatial variability of the zooplankton community in the Pearl River estuary according to correlation analysis results.