Zooplankton

Article By:

Sanders, Robert W. Department of Zoology, University of Georgia, Athens, Georgia.

Last reviewed:August 2020

DOI:https://doi.org/10.1036/1097-8542.756950

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• Zooplankton, published June 2014:Download PDF Get Adobe Acrobat Reader

Animals that live all or part of their life suspended and drifting in large aquatic environments. Zooplankton are animals that inhabit the water column of oceans and large freshwater systems, and they lack the means to counteract transport currents. Often consisting of microscopic organisms, but also including larger species (for example, jellyfish), zooplankton (Fig. 1) inhabit all layers of the aforementioned water bodies to the greatest depths sampled. Significantly, zooplankton constitute a major link between primary production and higher trophic levels in aquatic ecosystems. Typically, zooplankton have limited mobility and depend more on water turbulence to stay afloat. However, some zooplankton are capable of strong swimming movements and may migrate vertically from tens to hundreds of meters. All zooplankton, though, lack the ability to maintain their position against the movement of large water masses. In contrast to zooplankton, passively floating or weakly motile aquatic algae and plants are collectively known as phytoplankton. See also: Ecology; Ecosystem; Freshwater ecosystem; Marine ecology; Phytoplankton; Trophic ecology

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