Abstract: In 2000-2003,an investigation was made on the dynamics of rotifer and crustacean zooplankton in the Feilaixia Reservoir which was constructed in 1999.Sixty-eight species of rotifera,18 species of cladocera,and 13 species of copepoda were observed.The abundance of rotifera,cladocera and copepoda was 0.2-88.6,01-13 and 0.4-13.8 ind·L^-1，respectively,with the peak occurred in March 2002,the fourth year after filling.When the filling started,rotifera was dominated firstly by Keratella cochlearis,and then by Synchaeta pectinata whose population size increased rapidly in March,2002.Since then,as the population of S.pectinata decreased,K.cochlearis became the dominant species.Diaphanosoma brachyurum and Bosmina longirostris were the alternate dominant cladoceran species at first,while B.longirostris became the predominant one after August 2001.As for copepoda,nauplii and copepodites,their young ones were often much more abundant than the adults.During investigation,the water retention time was less than 14 days,and the high flushing rate made the zooplankton abundance in the reservoir very low.The temporal variation of rotifera,cladocera and copepoda was primarily affected by water retention time.There was little evidence for the regulation of zooplankton’s temporal fluctuation by the changes in food quantity or quality.Only S.pectinata and B.longirostris had a strong positive correlation with chlorophyll a.In 2002,the year with the longest water retention time (14 days) and relatively rich food,the populations of S.pectinata and B.longirostris increased rapidly,and the ‘upsurge’ of zooplankton abundance was observed.

Key words: Soil-plant system, Heavy metal, Organic pollutant, Combined pollution