摘要：Investigations of protozoa were carried out during four surveys of East Dongting Lake, China. A total of 160 protozoan species belonging to 71 genera was identified, of which 53 were flagellates, 37 sarcodines, and 70 ciliates. Among them, Peritrichida (32.6% of frequency), Arcellinida (16.2%), Volvocales (13.6%), Peridiniales (13.1%), and Chrysomonadales (9.1%) were the main groups and contributed to 84.5% of the overall species. Ciliates were mainly composed of sessile species and small species. The total protozoan abundance varied from 2,400 cells L -1 to 20,250 cells L -1 . The highest protozoan abundance occurred in spring; the lowest number was in autumn. The highest abundance of ciliates occurred in spring and winter, whereas flagellates developed the highest abundance in summer and autumn. Pearson correlation analysis and linear regressions indicated that chlorophyll a and water velocity were the main factors affecting temporal and spatial variations of the protozoan abundance.
