摘要：Seasonal variations of planktonic ciliates, with reference to environmental variables, and the relationship between ciliates and their prey were examined for one year in a shallow and eutrophic Korean stream. Large-sized ciliates (>50 μm), such as Hypotrichia sp., Phascolodon vorticella, and Codonella cratera co-dominated with solitary phytoplankton like Stephanodiscus sp. and Cryptomonas ovata in winter and spring. Particularly, the abundance of Phascolodon vorticella was correlated with the abundance of Stephanodiscus sp. (r=0.85, p0.318), which are similar in structure but different in size. Small-sized ciliates (<30 μm) mostly comprised Vorticella spp., Rimostrombidium hyalinum, and Halteria spp. and co-occurred with bacteria in warm seasons. These results suggest that the seasonal distribution of freshwater planktonic ciliates is determined by variations in their prey populations.
