'Zooplankton' are the
heterotrophic (or
detritivorous) component of the
plankton that drift in the
water column of
oceans,
seas, and bodies of
fresh water. The name is derived from the
Greek terms, ("zoon") meaning "
animal", and πλαγκτος ("planktos") meaning "wanderer" or "drifter"
[1]. Many zooplankton are too small to be individually seen with the
unaided eye.
Zooplankton is a broad categorisation spanning a range of
organism sizes that includes both small
protozoans and large
metazoans. It includes
holoplanktonic organisms whose complete
life cycle lies within the plankton, and
meroplanktonic organisms that spend part of their life cycle in the plankton before graduating to either the
nekton or a
sessile,
benthic existence.
Ecologically important protozoan zooplankton groups include the
foraminiferans,
radiolarians and
dinoflagellates (the latter are often
mixotrophic). Important metazoan zooplankton include
cnidarians such as
jellyfish and the
Portuguese Man o' War,
crustaceans such as
copepods and
krill,
molluscs such as
pteropods and
chordates such as
salps and juvenile
fish. This wide
phylogenetic range includes a similarly wide range in
feeding behaviour: passive
filter feeding, active
predation and even
symbiosis with
autotrophic phytoplankton. Zooplankton feed on
bacterioplankton, phytoplankton, other zooplankton (sometimes
cannibalistically),
detritus (or
marine snow) and even nektonic organisms.
Through their consumption and processing of phytoplankton (and other food sources), zooplankton play an important role in aquatic
food webs, both as a resource for consumers on higher
trophic levels and as a conduit for packaging the organic material in the
biological pump.
References
1. Introductory Oceanography, , H. V., Thurman, Prentice Hall College, 1997,
See also
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Bacterioplankton
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Biological pump
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Diel vertical migration
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Iron fertilization
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Ocean acidification
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Phytoplankton
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Plankton
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Primary production
External links
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Plankton
★ Net, images of planktonic species