[plangk-tuh
n] 
| the aggregate of passively floating, drifting, or somewhat motile organisms occurring in a body of water, primarily comprising microscopic algae and protozoa. |
[plangk-ton-ik] , adjective | plank·ton (plāngk'tən) n. The collection of small or microscopic organisms, including algae and protozoans, that float or drift in great numbers in fresh or salt water, especially at or near the surface, and serve as food for fish and other larger organisms. [German, from Greek, neuter of planktos, wandering, from plazein, to turn aside; see plāk-2 in Indo-European roots.] plank·ton'ic (-tŏn'ĭk) adj. |