The animal, Eucalanus crassus , was tethered with a dog hair. Algae, Lauderia borealis, which forms chains, were in the water at natural densities.
The flow is generated by the movement of the mouth parts. The inner mouth parts remain motionless until a chain is close-by. Then a fast movement is executed to capture the algal chain. The chain is positioned and the animal starts to feed on one cell at the time.
This clip is from a high-speed movie made in 1978 by Miquel Alcaraz, Gus Paffenhofer, and Rudi Strickler in Strickler’s laboratory. The clip was transferred to digital video. The clip is 37.5 seconds long at 30 frames per second, but was originally made at 500 frames per second. Therefore, the real scene is only 2 1/4 seconds in duration.