Compositional differences among planktonic ciliate communities in four subtropical eutrophic lakes in China

Ciliate community composition was investigated in four subtropical eutrophic lakes with cyanobacterial blooms in three seasons during 2009-2010 using the quantitative protargol staining approach. Among the four lakes, Lake Taihu and Chaohu are situated in the mid-lower Yangtze Plain near sea level, and Lake Dianchi and Xingyunhu are located on the Yunnan-Kweichow Plateau. A total of 102 ciliate species, representing 15 orders and 66 genera, were studied. Ciliate communities in Lake Taihu and Chaohu were characterized by abundant algivorous and mixotrophic oligotrichs and prostomatids, while Lake Dianchi and Xingyunhu ciliate communities were primarily characterized by voracious bacterivorous scuticociliates and peritrichids. Cluster analysis based on the transformed square root of ciliate abundance showed that samples from Lake Taihu and Chaohu composed one group whereas samples from Lake Dianchi and Xingyunhu composed another group in each season. Our results indicated that all dominant ciliate species are ubiquitous and that species dominance is regulated by different factors in different subtropical eutrophic lakes.