Swimming dynamics and vertical distribution of the ciliate Blepharisma persicinum Perty in laboratory cultures

The ciliate Blepharisma persicinum Perty has been found to be positively geotaxic. Statistical analyses suggest that time of day and CO 2 or O 2 stress have a significant influence on the geotaxic behavior of the animals. The swimming rate was also determined experimentally to be 320 μm · s −1 . The force exerted in swimming at this speed by an average animal was calculated to be 4.1 × 10 −5 dynes.