Particle size selectivity of two marine ciliates - Balanion comatum Wulff and Strombidium sp.

Food selectivity of marine ciliates Balanion comatum Wulff and Strombidium sp. (mean size of cell 19 μm) were studied in situ during incubation with wheat starch particles as a surrogate food. Range of particles ingested by Balanion comatum was 1.25–7.50 μm with preference for 3.75 μm particles (statistically significant result). Strombidium sp. engulfed particles ranging from 1.25 μm to 5.00 μm also with preference for 3.75 μm particles. In the Baltic Sea size range of particles preferred by both ciliates is dominated by nanoflagellates.