Glossary of "Ecology (6th ed.)" by Krebs (2009)
- animal portion of the plankton; the animal community in marine and freshwater environments that floats free in the water, independent of the shore and the bottom, moving passively with the currents.
Glossary of "Biogeography (9th ed.)" by Cox et al. (2016)
Glossary of "Environmental Science: Earth as a Living Planet (7th ed.)" by Botkin & Keller (2010)
- Small aquatic invertebrates that live in the sunlit waters of streams, lakes, and oceans and feed on algae and other invertebrate animals.
- Botkin, D. B. & Keller, E. A. 2010. Environmental Science: Earth as a Living Planet, 7th ed. -xxviii + 665 pp. John Wiley & Sons, Inc., New York.
- Cox, C. B., Moore, P. D. & Ladle, R. J. 2016. Biogeography: An Ecological and Evolutionary Approach, 9th ed. - xiii + 482 pp. Wiley Blackwell, Chichester.
- Krebs, C. J. 2009. Ecology, 6th ed. -xvi + 655 pp. Pearson Benjamin Cummings, San Francisco.