n.
Small floating or weakly swimming animals that drift with water currents and, with phytoplankton , make up the planktonic food supply on which almost all oceanic organisms ultimately depend (see plankton ).
Included are many animals, from single-celled radiolarians to the eggs or larvae of herrings, crabs, and lobsters. Permanent plankton (holoplankton), such as protozoans and copepods , spend their lives as plankton. Temporary plankton (meroplankton), such as young starfish, clams, worms, and other bottom-dwelling animals, live and feed as plankton until they become adults.