Acartia

Acartia is a genus of marine calanoid copepods. They are epipelagic, estuarine, zooplanktonic found throughout the oceans of the world, primarily in temperate regions. Species This genus contains the majority of species in the family Acartiidae: 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 isn't killed off by a momentary warming followed again by colder temperatures. Feeding Arcatia primarily feed on phytoplankton and are also known to consume rotifers, ciliates, and their own eggs and nauplii.