''Acartia'' is a genus of marine calanoid

copepod Copepods (; meaning "oar-feet") are a group of small crustaceans found in nearly every freshwater and saltwater habitat (ecology), habitat. Some species are planktonic (inhabiting sea waters), some are benthos, benthic (living on the ocean floor) ...

s. They are epipelagic,

estuarine An estuary is a partially enclosed coastal body of brackish water with one or more rivers or streams flowing into it, and with a free connection to the open sea. Estuaries form a transition zone between river environments and maritime environment ...

, zooplanktonic found throughout the oceans of the world, primarily in temperate regions.

Classification

This genus contains the majority of species in the family

Acartiidae Acartiidae is a family of calanoid copepods distinguishable by the rostral margin not being extended. They are epipelagic, plankton Plankton are the diverse collection of organisms found in Hydrosphere, water (or atmosphere, air) that are u ...

: *'' Acartia adriatica'' Steuer, 1910 *'' Acartia amboinensis'' Carl, 1907 *''

Acartia arbruta ''Acartia'' is a genus of marine calanoid copepods. They are epipelagic, estuarine, zooplanktonic found throughout the oceans of the world, primarily in temperate regions. Classification This genus contains the majority of species in the fa ...

'' Smith ''et al''., 2021 *'' Acartia australis'' Farran, 1936 *''

Acartia bacorehuisensis ''Acartia'' is a genus of marine calanoid copepods. They are epipelagic, estuarine, zooplanktonic found throughout the oceans of the world, primarily in temperate regions. Classification This genus contains the majority of species in the fam ...

'' Zamora-Sánchez & Gómez-Aguirre, 1986 *''

Acartia bermudensis ''Acartia'' is a genus of marine calanoid copepods. They are epipelagic, estuarine, zooplanktonic found throughout the oceans of the world, primarily in temperate regions. Classification This genus contains the majority of species in the fa ...

'' Esterly, 1911 *''

Acartia bifilosa ''Acartia'' is a genus of marine calanoid copepods. They are epipelagic, estuarine, zooplanktonic found throughout the oceans of the world, primarily in temperate regions. Classification This genus contains the majority of species in the fa ...

'' (Giesbrecht, 1881) *'' Acartia bilobata'' Abraham, 1970 *'' Acartia bispinosa'' Carl, 1907 *'' Acartia bowmani'' Abraham, 1976 *'' Acartia cagayanensis'' Sakaguchi & Ueda, 2020 *'' Acartia californiensis'' Trinast, 1976 *'' Acartia centrura'' Giesbrecht, 1889 *'' Acartia chilkaensis'' Sewell, 1919 *''

Acartia clausi ''Acartia clausi'' is a species of marine copepod belonging to the family Acartiidae. This species was previously thought to have a worldwide distribution but recent research has restricted its range to coastal regions of the north-eastern Atlan ...

'' Giesbrecht, 1889 *'' Acartia danae'' Giesbrecht, 1889 *'' Acartia denticornis'' Brady, 1883 *'' Acartia discaudata'' (Giesbrecht, 1882) *'' Acartia dweepi'' Haridas & Madhupratap, 1978 *'' Acartia edentata'' Srinui, Ohtsuka & Metillo in Srinui, Ohtsuka, Metillo & Nishibori, 2019 *'' Acartia ensifera'' Brady, 1899 *'' Acartia enzoi'' Crisafi, 1974 *'' Acartia erythraea'' Giesbrecht, 1889 *''

Acartia fancetti ''Acartia'' is a genus of marine calanoid copepods. They are epipelagic, estuarine, zooplanktonic found throughout the oceans of the world, primarily in temperate regions. Classification This genus contains the majority of species in the fa ...

'' McKinnon, Kimmerer & Benzie, 1992 *''

Acartia floridana ''Acartia'' is a genus of marine calanoid copepods. They are epipelagic, estuarine, zooplanktonic found throughout the oceans of the world, primarily in temperate regions. Classification This genus contains the majority of species in the fa ...

'' Davis, 1948 *''

Acartia forcipata ''Acartia'' is a genus of marine calanoid copepods. They are epipelagic, estuarine, zooplanktonic found throughout the oceans of the world, primarily in temperate regions. Classification This genus contains the majority of species in the fa ...

'' I. C. Thompson & A. Scott ''in'' Thompson, Scott & Herdman, 1898 *'' Acartia forticrusa'' Soh, Moon, Park, Bun & Venmathi Maran, 2013 *''

Acartia fossae ''Acartia'' is a genus of marine calanoid copepods. They are epipelagic, estuarine, zooplanktonic found throughout the oceans of the world, primarily in temperate regions. Classification This genus contains the majority of species in the fam ...

'' Gurney, 1927 *'' Acartia hongi'' Soh & Suh, 2000 *'' Acartia hudsonica'' Pinhey, 1926 *''

Acartia italica ''Acartia'' is a genus of marine calanoid copepods. They are epipelagic, estuarine, zooplanktonic found throughout the oceans of the world, primarily in temperate regions. Classification This genus contains the majority of species in the fam ...

'' Steuer, 1910 *'' Acartia japonica'' Mori, 1940 *''

Acartia jilletti ''Acartia jilletti'' is a species of marine copepod belonging to the family Acartiidae. This species has a total length of up to 1 mm. It is very similar to ''Acartia ensifera ''Acartia ensifera'' is a species of marine copepod belonging ...

'' Bradford, 1976 *''

Acartia laxa ''Acartia'' is a genus of marine calanoid copepods. They are epipelagic, estuarine, zooplanktonic found throughout the oceans of the world, primarily in temperate regions. Classification This genus contains the majority of species in the fam ...

'' Dana, 1852 *''

Acartia lefevreae ''Acartia lefevreae'' is a species of copepod belonging to the family Acartiidae. This species was discovered when specimens previously identified as ''Acartia clausi ''Acartia clausi'' is a species of marine copepod belonging to the family Ac ...

'' Bradford, 1976 *''

Acartia levequei ''Acartia'' is a genus of marine calanoid copepods. They are epipelagic, estuarine, zooplanktonic found throughout the oceans of the world, primarily in temperate regions. Classification This genus contains the majority of species in the fa ...

'' Grice, 1964 *'' Acartia lilljeborgii'' Giesbrecht, 1889 *'' Acartia limpida'' Dana, 1849 *''

Acartia longiremis ''Acartia'' is a genus of marine calanoid copepods. They are epipelagic, estuarine, zooplanktonic found throughout the oceans of the world, primarily in temperate regions. Classification This genus contains the majority of species in the fam ...

'' (Lilljeborg, 1853) *'' Acartia longisetosa'' Brady, 1914 *''

Acartia macropus ''Acartia'' is a genus of marine calanoid copepods. They are epipelagic, estuarine, zooplanktonic found throughout the oceans of the world, primarily in temperate regions. Classification This genus contains the majority of species in the f ...

'' Cleve, 1900 *''

Acartia margalefi ''Acartia'' is a genus of marine calanoid copepods. They are epipelagic, estuarine, zooplanktonic found throughout the oceans of the world, primarily in temperate regions. Classification This genus contains the majority of species in the fa ...

'' Alcaraz, 1976 *''

Acartia mediterranea ''Acartia'' is a genus of marine calanoid copepods. They are epipelagic, estuarine, zooplanktonic found throughout the oceans of the world, primarily in temperate regions. Classification This genus contains the majority of species in the fam ...

'' Pesta, 1909 *'' Acartia mollicula'' Pavlova & Shmeleva, 2010 *''

Acartia mossi ''Acartia'' is a genus of marine calanoid copepods. They are epipelagic, estuarine, zooplanktonic found throughout the oceans of the world, primarily in temperate regions. Classification This genus contains the majority of species in the f ...

'' (Norman, 1878) *''

Acartia nadiensis ''Acartia'' is a genus of marine calanoid copepods. They are epipelagic, estuarine, zooplanktonic found throughout the oceans of the world, primarily in temperate regions. Classification This genus contains the majority of species in the fa ...

'' Lee, S, Soh & W. Lee, 2019 *''

Acartia nana ''Acartia'' is a genus of marine calanoid copepods. They are epipelagic, estuarine, zooplanktonic found throughout the oceans of the world, primarily in temperate regions. Classification This genus contains the majority of species in the f ...

'' Brady, 1914 *''

Acartia negligens ''Acartia'' is a genus of marine calanoid copepods. They are epipelagic, estuarine, zooplanktonic found throughout the oceans of the world, primarily in temperate regions. Classification This genus contains the majority of species in the fam ...

'' Dana, 1849 *'' Acartia ohtsukai'' Ueda & Bucklin, 2006 *''

Acartia omorii ''Acartia omorii'' is a species of marine copepod belonging to the family Acartiidae. This species was discovered when specimens previously identified as ''Acartia clausi ''Acartia clausi'' is a species of marine copepod belonging to the famil ...

'' Bradford, 1976 *'' Acartia pacifica'' Steuer, 1915 *''

Acartia pietschmani ''Acartia'' is a genus of marine calanoid copepods. They are epipelagic, estuarine, zooplanktonic found throughout the oceans of the world, primarily in temperate regions. Classification This genus contains the majority of species in the fam ...

'' Pesta, 1912 *'' Acartia plumosa'' T. Scott, 1894 *''

Acartia ponteloides ''Acartia'' is a genus of marine calanoid copepods. They are epipelagic, estuarine, zooplanktonic found throughout the oceans of the world, primarily in temperate regions. Classification This genus contains the majority of species in the f ...

'' (Kritchagin, 1873) *''

Acartia ransoni ''Acartia'' is a genus of marine calanoid copepods. They are epipelagic, estuarine, zooplanktonic found throughout the oceans of the world, primarily in temperate regions. Classification This genus contains the majority of species in the fa ...

'' Vaissière, 1954 *'' Acartia remivagantis'' Oliveira, 1946 *''

Acartia sarojus ''Acartia'' is a genus of marine calanoid copepods. They are epipelagic, estuarine, zooplanktonic found throughout the oceans of the world, primarily in temperate regions. Classification This genus contains the majority of species in the fa ...

'' Madhupratap & Haridas, 1994 *''

Acartia seshaiyai ''Acartia'' is a genus of marine calanoid copepods. They are epipelagic, estuarine, zooplanktonic found throughout the oceans of the world, primarily in temperate regions. Classification This genus contains the majority of species in the f ...

'' Subbaraju, 1968 *''

Acartia simplex ''Acartia simplex'' is a species of marine copepod belonging to the family Acartiidae. It is found in the waters near Australia and New Zealand. This species, just under 1 mm in length, is rather similar to ''Acartia ensifera'' but can be d ...

'' G. O. Sars, 1905 *''

Acartia sinjiensis ''Acartia'' is a genus of marine calanoid copepods. They are epipelagic, estuarine, zooplanktonic found throughout the oceans of the world, primarily in temperate regions. Classification This genus contains the majority of species in the f ...

'' Mori, 1940 *''

Acartia southwelli ''Acartia'' is a genus of marine calanoid copepods. They are epipelagic, estuarine, zooplanktonic found throughout the oceans of the world, primarily in temperate regions. Classification This genus contains the majority of species in the fam ...

'' Sewell, 1914 *''

Acartia spinata ''Acartia'' is a genus of marine calanoid copepods. They are epipelagic, estuarine, zooplanktonic found throughout the oceans of the world, primarily in temperate regions. Classification This genus contains the majority of species in the fa ...

'' Esterly, 1911 *'' Acartia spinicauda'' Giesbrecht, 1889 *'' Acartia steueri'' Smirnov, 1936 *''

Acartia teclae ''Acartia teclae'' is a species of copepod belonging to the family Acartiidae. This species was discovered when specimens previously identified as ''Acartia clausi'' were examined and found to belong to a separate species. This species appears to ...

'' Bradford, 1976 *''

Acartia tonsa ''Acartia tonsa'' is a species of marine copepod in the family Acartiidae. Distribution ''Acartia tonsa'' is a species of calanoid copepod that can be found in a large portion of the world's estuaries and areas of upwelling where food concentrat ...

'' Dana, 1849 *''

Acartia tranteri ''Acartia tranteri'' is a species of marine copepod belonging to the family Acartiidae Acartiidae is a family of calanoid copepods distinguishable by the rostral margin not being extended. They are epipelagic, plankton Plankton are the d ...

'' Bradford, 1976 *''

Acartia tropica ''Acartia'' is a genus of marine calanoid copepods. They are epipelagic, estuarine, zooplanktonic found throughout the oceans of the world, primarily in temperate regions. Classification This genus contains the majority of species in the fa ...

'' Ueda & Hiromi, 1987 *''

Acartia tsuensis ''Acartia'' is a genus of marine calanoid copepods. They are epipelagic, estuarine, zooplanktonic found throughout the oceans of the world, primarily in temperate regions. Classification This genus contains the majority of species in the f ...

'' ItoTak, 1956 *''

Acartia tumida ''Acartia'' is a genus of marine calanoid copepods. They are epipelagic, estuarine, zooplanktonic found throughout the oceans of the world, primarily in temperate regions. Classification This genus contains the majority of species in the fa ...

'' Willey, 1920

Reproductive and life cycle

Female ''Acartia'' release eggs freely in the water. Nauplii hatch and undergo six distinct life stages to become copepodites and then undergo another six life stages to become fully mature copepods. Some species of ''Arcatia'' are known to exhibit a diapause, a resting period when the species is dormant, as a part of their life cycle. These species produce "resting eggs" when environmental conditions are unfavorable for the development and growth of nauplii. Individual females can switch between producing resting eggs and subitaneous eggs (eggs that hatch immediately) as environmental conditions change. Resting eggs accumulate in the sediment and hatch when conditions are optimal. Production of resting eggs is driven by water temperature variations. Some species (''A. hudsonica'') produce resting eggs when water temperatures rise above a certain threshold, while others (''A. tonsa, A. califoriensis'') have been observed to produce resting eggs when water temperatures fall below a certain threshold. Hatching and development of the species occur when the water cools (''A. hudonica'') or warms (''A. tonsa, A. califoriensis''). Additionally, ''A. califoriensis'' is known to be adapted to anomalous water temperature variations. Hatching is only followed by a period of steady water temperatures in the favorable range. This ensures that a generation of the species is not killed off by a momentary warming followed again by colder temperatures.

Diet

''Arcatia'' primarily feed on

phytoplankton Phytoplankton () are the autotrophic (self-feeding) components of the plankton community and a key part of ocean and freshwater ecosystems. The name comes from the Greek words (), meaning 'plant', and (), meaning 'wanderer' or 'drifter'. Ph ...

and are also known to consume

rotifer The rotifers (, from the Latin , "wheel", and , "bearing"), commonly called wheel animals or wheel animalcules, make up a phylum (Rotifera ) of microscopic and near-microscopic pseudocoelomate animals. They were first described by Rev. John H ...

s, ciliates, and their own eggs and nauplii. ''Arcatia'' feeding patterns are asymptotic relative to the abundance of food. When food is widely abundant ''Arcatia'' approach a maximum food intake. When there is less food available, feeding adjusts to rates that correlate with food availability.

Behaviour

In a study of ''A. tonsa'' in the Narragansett Bay the species was found to exhibit a diel feeding pattern, that is, a night feeding pattern. The diel feeding cycle was tested under a variety of light conditions and was found to be

endogenous Endogenous substances and processes are those that originate from within a living system such as an organism, tissue, or cell. In contrast, exogenous substances and processes are those that originate from outside of an organism. For example, es ...

, not related to light availability, but persistent regardless of whether the copepods were subjected to light or dark. This feeding pattern is only known to be disrupted at extremely low food levels, implying that either "food limitation has over-ridden other factors governing diel feeding rhythms and induced continuous feeding, or that a synchronized population-wide feeding rhythm has given way to intermittent, asynchronous feeding among individuals." ''Arcatia'' are also known to exhibit a

diel vertical migration Diel vertical migration (DVM), also known as diurnal vertical migration, is a pattern of movement used by some organisms, such as copepods, living in the ocean and in lakes. The word ''diel'' comes from the Latin ''dies'' day, and means a 24-h ...

pattern, swimming to depths during the day and rising to surface waters at night. The diel vertical migration of ''A. tonsa'' was seen to be effected by light exposure: when exposed to continuous light the copepods did not migrate to the surface. Both diel patterns are thought to be primarily adaptive behavior to avoid visual predators. The mechanism of the diel vertical migration of ''Arcatia'' has been explored further to solve the question of whether the copepods react to chemical signals indicating the presence of predators, physical stimuli resulting from the movement of predator fish in the water, or visual cues based on the changing light modified by a much larger predator. In a study of ''A. hudsonica'', the chemical response was ruled out. Additionally, other studies of ''Arcatia'' (''A. longiremis, A. grani'' and ''A. discandata'') were found to have less chemoreceptors and more

mechanoreceptive A mechanoreceptor, also called mechanoceptor, is a sensory receptor that responds to mechanical pressure or distortion. Mechanoreceptors are innervated by sensory neurons that convert mechanical pressure into electrical signals that, in animals, a ...

sensory hairs than other marine copepods, suggesting that diel feeding and migration patterns in ''Arcatia'' are primarily driven by physical and visual cues.

References

{{Taxonbar, from=Q3808855 Calanoida