Copepod 207036 225806081 2008-07-15T14:18:15Z Babbage 29688 briefly explain unfamiliar terms {{Taxobox | name = Copepod | image = copepodkils.jpg | image_width = 250px | regnum = [[Animal]]ia | phylum = [[Arthropod]]a | subphylum = [[Crustacean|Crustacea]] | classis = [[Maxillopoda]] | orderis = '''Copepoda''' | subclassis_authority = [[Henri Milne-Edwards|H. Milne-Edwards]], 1840 | subdivision_ranks = Orders | subdivision = [[Calanoida]]<br /> [[Cyclopoida]]<br /> [[Gelyelloida]]<br /> [[Harpacticoida]]<br /> [[Misophrioida]]<br /> [[Monstrilloida]]<br /> [[Mormonilloida]]<br /> [[Platycopioida]]<br /> [[Poecilostomatoida]]<br /> [[Siphonostomatoida]] }} [[Image:Acanthochondria_cornuta on flounder.jpg|250px|thumb|''Acanthochondria cornuta'', an ectoparasite on [[Flounder]] in the [[North Sea]].]] '''Copepods''' are a group of small [[crustacean]]s found in the sea and nearly every [[fresh water|freshwater]] [[habitat (ecology)|habitat]] and they constitute the biggest source of protein in the oceans.<ref>[http://www.uni-oldenburg.de/zoomorphology/Biology.html Biology of Copepods] at [[Carl von Ossietzky University of Oldenburg]]</ref> Many species are [[plankton]]ic (drifting in sea waters), but more are [[benthos|benthic]] (living on the ocean floor), and some continental species may live in limno-terrestrial habitats and other wet terrestrial places, such as swamps, under leaf fall in wet forests, bogs, springs, ephemeral ponds and puddles, damp moss, or water-filled recesses ([[phytotelmata]]) of plants such as [[bromeliad]]s and [[pitcher plant]]s. Many live underground in marine and freshwater caves, [[sinkhole]]s, or stream beds. Copepods are sometimes used as [[bioindicator]]s (see [[particle (ecology)]]). ==Ecology== Planktonic copepods are important to global [[ecology]] and the [[carbon cycle]]; They are usually the dominant members of the [[zooplankton]], and are major food organisms for small [[fish]], [[whale]]s, [[seabird]]s and other [[crustacean]]s such as [[krill]] in the ocean and in fresh water. Some scientists say they form the largest animal [[biomass]] on earth. They compete for this title with [[Antarctic krill]] (''Euphausia superba''). Because of their smaller size and relatively faster growth rates, however, and because they are more evenly distributed throughout more of the world's oceans, copepods almost certainly contribute far more to the [[secondary productivity]] of the world's oceans, and to the global ocean [[carbon sink]] than [[krill]], and perhaps than all other groups of organisms together. The surface layers of the oceans are currently believed to be the world's largest [[carbon sink]], absorbing about 2 billion tonnes of carbon a year, the equivalent to perhaps a third of [[greenhouse gas|human carbon emissions]], thus reducing their impact. Many [[plankton]]ic copepods feed near the surface at night, then sink into deeper water during the day to avoid visual predators. Their moulted [[exoskeleton]]s, [[feces|faecal]] pellets and [[Respiration (physiology)|respiration]] at depth all bring [[carbon]] to the deep sea.<br> Some copepods are [[parasite|parasitic]]<ref>{{cite journal |quotes=no |author=H. L. Suh, J. D. Shim and S. D. Choi |year=1992 |title=Four Species of Copepoda (Poecilostomatoida) Parasitic on Marine Fishes of Korea |journal=[[Bulletin of the Korean Fisheries Society]] |volume=25 |issue=4 |pages=291–300}} (in Korean with English abstract)</ref><ref>See photograph at {{cite web | url = http://censeam.niwa.co.nz/outreach/blobfish.pdf | title = Blobfish / Psychrolutes microporos | accessdate = 2007-12-09 | format = PDF | work = | publisher = Census of Marine Life / [[National Institute of Water and Atmospheric Research|NIWA]]; photograph © NORFANZ 2003 | doi = }} Photograph taken by Parkinson, Kerryn and McPhee, Robin in June 2003.</ref> and have strongly modified bodies. They attach themselves to fish, sharks, marine mammals, and many kinds of invertebrates such as molluscs, tunicates, or corals. They live as endo- or ectoparasites on fish or invertebrates in fresh water as well as in marine environments. ==Characteristics== Copepods are typically {{convert|1|mm|in|lk=on}} to {{convert|2|mm|in}} long, with a teardrop shaped body and large [[Antenna (biology)|antennae]]. Although like other [[crustacean]]s they have an armoured [[exoskeleton]], they are so small that in most species this armour, and the entire body, is almost totally transparent. Copepods have a single eye, usually bright red and in the centre of the transparent head. Some polar copepods reach {{convert|1|cm|in|lk=in}}. Most of the smaller copepods feed directly on [[phytoplankton]], catching cells singly, but a few of the larger species are predators of their smaller relatives. Herbivorous copepods, particularly those in rich cold seas, store up energy from their food as oil droplets while they feed in the spring and summer [[plankton bloom]]s. These droplets may take up over half of the volume of the body in polar species. [[Image:Haeckel Copepoda.jpg|thumb|left|Copepods from [[Ernst Haeckel]]'s ''[[Kunstformen der Natur]]'']] Many species have neurons surrounded by [[myelin]], which is very rare among [[invertebrate]]s (other examples are some [[annelid]]s and [[malacostraca]]n crustaceans like [[Palaemonidae|palaemonid]] shrimp and [[penaeid]]s). Even rarer, the myelin is highly organized, resembling the well-organized wrapping found in vertebrates ([[Gnathostomata]]). Some copepods are very evasive and can jump with extreme speed over a few millimeters (warning: takes some time to load to the correct speed): [[Image:Cc3s.gif|frame|Slow-motion macrophotography video (50%) of juvenile [[Atlantic herring]] (38 mm) feeding on copepods - the fish approach from below and catch each copepod individually. In the middle of the image a copepod escapes successfully to the left.]]This scene was scanned with the [[ecoSCOPE]], an underwater high speed microscope. Very little is known about the details of these kinds of predator/prey interactions, in spite of their importance for global processes, because copepods are difficult to keep in the laboratory and lose most of their escape capacity, and herring are very fast, alert and evasive organisms and flee from normal camera systems or [[Scuba diving|scuba divers]]. ==Classification== Copepods form a [[Subclass (biology)|subclass]] belonging to the subphylum [[Crustacea]] (crustaceans). Some authors consider the copepods to be a full [[class (biology)|class]]. The group contains ten [[order (biology)|order]]s with some 14,000 described [[species]]. A scientist that studies copepods is a ''copepodologist''. ==Water supply== Copepods are sometimes found in the public mains water supply, especially systems where the water is not filtered, such as [[New York City]] and [[Boston, Massachusetts]]. This is not usually a problem in treated water supplies. In some tropical countries, such as [[Peru]] and [[Bangladesh]], a correlation has been found between copepods and [[cholera]] in untreated water, because the cholera bacteria attach to the surfaces of planktonic animals. The risk of cholera from infected water can be reduced by filtering out the copepods (and other matter), for example with a [[cloth filter]]. Copepods have been used successfully in [[Vietnam]] to control disease-bearing [[mosquitoes]] such as [[Aedes aegypti]] that transmit [[dengue]] fever and other human [[parasitic]] diseases. The copepods can be added to water-storage containers where the mosquitoes breed. Copepods, primarily of the genera ''Mesocyclops'' and ''Macrocyclops'', can survive for periods of months in the containers, if the containers are not completely drained by their users. They will attack, kill, and eat the younger 1st and 2nd [[instar]] larvae of the mosquitoes. This [[biological control]] method is complemented by community trash removal and recycling to eliminate other possible mosquito-breeding sites. Because the water in these containers is drawn from uncontaminated sources such as rainfall, there is little risk of contamination by cholera bacteria, and in fact no cases of cholera have been linked to copepods introduced into water-storage containers. Trials using copepods to control container-breeding mosquitoes are underway in several other countries, including [[Thailand]] and the southern [[U.S.A.]] ==References== {{citation style}} {{reflist}} == External links == * [http://www.tafi.org.au/zooplankton/imagekey/copepoda/index.html Copepod fact sheet - Guide to the marine zooplankton of south eastern Australia] * [http://copepodes.obs-banyuls.fr/en/ Diversity and geographical distribution of pelagic copepoda] * [http://www.uwm.edu/~jrs/COPEPODS%20CENTRAL.htm Rudi Strickler copepod videos] * [http://jaffeweb.ucsd.edu/pages/celeste/copepods.html The virtual copepod page] * [http://www.nmnh.si.edu/iz/copepod/ Copepod World] * [http://www.nsf.gov/news/speeches/colwell/rc01_anatlesson/tsld024.htm Copepods and cholera in untreated water] * [http://www.copepod.de/plankton.html Copepod links, www.copepod.de] * [http://www.kosherwater.com/reprints.htm CNN report: New York Times: The Water's Fine, but Is It Kosher?] * [http://books.google.com/books?id=TgUNAAAAIAAJ&dq=isbn:0871692406 Copepodologist's Cabinet: A Biographical & Bibliographical History] ==See also== *[[World Association of Copepodologists]] [[Category:Maxillopoda]] [[Category:Indicator species]] [[Category:Bioindicators]] [[Category:Copepods| ]] [[ar:مجدافية الأرجل]] [[ca:Copèpode]] [[de:Ruderfußkrebse]] [[et:Aerjalalised]] [[el:Κωπήποδα]] [[es:Copepoda]] [[fa:پاروپایان]] [[fr:Copepoda]] [[gl:Copépoda]] [[id:Copepoda]] [[it:Copepoda]] [[he:שטרגליים]] [[la:Copepoda]] [[lv:Airkājvēži]] [[lt:Irklakojai vėžiagyviai]] [[nl:Eenoogkreeftjes]] [[ja:カイアシ類]] [[no:Hoppekreps]] [[nn:Hoppekreps]] [[pl:Widłonogi]] [[pt:Copépode]] [[fi:Hankajalkaiset]] [[sv:Hoppkräftor]]