The study of marine plankton has traditionally focused on those or ganisms that appeared to have obvious ecological significance in un derstanding the major patterns of biological productivity, trophic relations, community structure, and the dynamic interaction of living things with the physical environment. Not infrequently, this thrust has centered on the apparently most abundant and/or larger members of the plankton community, including significant primary producers such as the diatoms, nonthecate algae, and flagellates, or the major con sumers--copepods, gelatinous metazoa, and other...

The protozoa are an eclectic assemblage of organisms encompassing a wide range of single-celled and multiple-celled colonial organisms lacking tissue organiza tion, but exhibiting remarkably refined biological behavior. In some modern classifications, they are classified as a subkingdom among the Protista (eukary otic single-celled organisms). Although they are not considered a formal cate gory by some taxonomists and some biologists consider the name inappropriate (inferring that they are the first unicellular animals, although some photosynthe size), it is still convenient to consider this...