From Longman Dictionary of Contemporary Englishplanktonplank‧ton /ˈplæŋktən/ noun [uncountable] HBPHBAthe very small forms of plant and animal life that live in water, especially the sea, and are eaten by fish
Examples from the Corpus
plankton• Creatures that float near the surface of the seas are called plankton.• The ocean had so much plankton in it that the sea itself had changed colour.• Against the pale background the plankton which swarmed on the surface were clearly visible.• All creatures that live in the plankton have to devise means of staying afloat.• Cod, for instance, lay about nine million eggs into the plankton.• Because the creatures of the plankton individually are small, they are not always visible to the naked eye.• Through most of the summer, then, the plankton in open ocean is gradually depleted.• The plankton, he said, produce natural chemicals whose effect is similar to that of oil on the water.Origin plankton (1800-1900) German Greek, from planktos “wandering”, from plazesthai “to wander” 