Aurelia aurita (also called the common jellyfish, moon jellyfish, moon jelly or saucer jelly) is a species of the family Ulmaridae.
The jellyfish is almost entirely translucent, usually about in diameter, and can be recognized by its four horseshoe-shaped , easily seen through the top of the bell. It feeds by collecting medusae, plankton, and with its tentacles, and bringing them into its body for digestion. It is capable of only limited motion, and drifts with the current, even when swimming.
The moon jelly differs from many jellyfish in that they lack long, potent stinging tentacles. Instead they have hundreds of short, fine tentacles that line the bell margin. The sting has no effect on humans.
Distribution
The species Aurelia aurita is considered to be an ecological generalist and inhabits worldwide habitats.
Aurelia aurita lives in ocean water temperatures ranging from ; with optimum temperatures of . It prefers temperate seas with consistent currents. It has been found in waters with salinity as low as 6 parts per thousand.
Feeding
Aurelia aurita and other Aurelia species feed on plankton that includes organisms such as mollusks, crustaceans, tunicate larvae, , young , , , eggs, fish eggs, and other small organisms. Occasionally, they are also seen feeding on gelatinous zooplankton such as hydromedusae and ctenophores.
The food is caught with its nematocyst-laden tentacles, tied with mucus, brought to the gastrovascular cavity, and passed into the cavity by ciliated action. There, digestion enzymes from break down the food. Little is known about the requirements for particular vitamins and minerals, but due to the presence of some , we can deduce in general that A. aurita can process , , and .
Body system
Aurelia does not have respiratory parts such as , , or trachea; it respires by diffusion oxygen from water through the thin membrane covering its body. Within the gastrovascular cavity, low oxygenated water can be expelled and high oxygenated water can come in by Cilium action, thus increasing the diffusion of oxygen through the cell.
The basic body plan of Aurelia consists of several parts. The animal lacks respiratory, excretion, and circulatory systems. The adult medusa of Aurelia, with a transparent look, has an umbrella margin membrane and tentacles that are attached to the bottom.
The medusae are either male or female.[ Tree of Life – NJ Jellyfish – Aurelia aurita]
A 2015 study has found that A. aurita are capable of life cycle reversal where individuals grow younger instead of older, akin to the "immortal jellyfish" Turritopsis dohrnii.
There has been a study presenting that Aurelias body system is not significantly affected by artificial materials like , which can be found in cosmetic and personal care products. Aurelia aurita was able to recognize that microbeads were not food so there was not any physiological or histological harm.
Predators
Aurelia aurita have high proportions of polyunsaturated fatty acids compared to other prey types and are a source of vital nutrients for predators.
Aurelia jellyfish naturally die after living and reproducing for several months. It is probably rare for these moon jellies to live more than about six months in the wild, although specimens cared for in public aquarium exhibits typically live several to many years. In the wild, the warm water at the end of summer combines with exhaustive daily reproduction and lower natural levels of food for tissue repair, leaving these jellyfish more susceptible to and other disease problems that likely lead to the demise of most individuals. Such problems are responsible for the demise of many smaller species of jellyfish.
Some parasites attack Aurelia aurita, as well as most other species of jellyfish.
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Further reading
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