Moon Jelly
Aurelia aurita
Summary 2
Aurelia aurita (also called the moon jelly, moon jellyfish, common jellyfish, or saucer jelly) is a widely studied species of the genus Aurelia. All species in the genus are closely related, and it is difficult to identify Aurelia medusae without genetic sampling; most of what follows applies equally to all species of the genus.
Body system 3
Aurelia does not have respiratory parts such as gills, lungs or trachea; it respires by diffusing 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 ciliated action, thus increasing the diffusion of oxygen through cell. The large surface area membrane to volume ratio helps Aurelia to diffuse more oxygen and nutrients into the cells.
The basic body plan of Aurelia consists of several parts. The animal lacks respiratory, excretory, 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. It has four bright gonads that are under the stomach. Food travels through the muscular manubrium while the radial canals help disperse the food. There is a middle layer of mesoglea, gastrodervascular cavity with gastrodermis, and epidermis. There is a nerve net that is responsible for contractions in swimming muscles and feeding responses. Adult medusae can have diameters up to 40 cm (16 in).
The medusae are either male or female. The young larval stage, a planula, has small ciliated cells and after swimming freely in the plankton for a day or more, settles on an appropriate substrate, where it changes into a special type of polyp called a "scyphistoma", which divides by strobilation into small ephyrae that swim off to grow up as medusae. There is an increasing size from starting stage planula to ephyra, from less than 1 mm in the planula stage, up to about 1 cm in ephyra stage, and then to several cm in diameter in the medusa stage.
A recent study has found that A. aurita are capable of lifecycle reversal where individuals grow younger instead of older, akin to the "immortal jellyfish" Turritopsis dohrnii.
There has been a study presenting that Aurelia's body system isn't significantly affected by artificial materials like microbeads, which can be found in cosmetic and personal care products. Aurelia aurita was able to recognize that microbeads were not food so there wasn't any physiological or histological harm.
Feeding 3
Aurelia aurita and other Aurelia species feed on plankton that includes organisms such as mollusks, crustaceans, tunicate larvae, rotifers, young polychaetes, protozoans, diatoms, eggs, fish eggs, and other small organisms. Occasionally, they are also seen feeding on gelatinous zooplankton such as hydromedusae and ctenophores. Both the adult medusae and larvae of Aurelia have nematocysts to capture prey and also to protect themselves from predators.
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, digestive enzymes from serous cell break down the food. Little is known about the requirements for particular vitamins and minerals, but due to the presence of some digestive enzymes, we can deduce in general that A. aurita can process carbohydrates, proteins and lipids.
Sources and Credits
- (c) Brian Honohan, some rights reserved (CC BY-NC-SA), http://www.flickr.com/photos/brian-honohan/5126424738/
- Adapted by North Carolina Aquarium at Fort Fisher from a work by (c) Wikipedia, some rights reserved (CC BY-SA), http://en.wikipedia.org/wiki/Aurelia_aurita
- (c) Wikipedia, some rights reserved (CC BY-SA), https://en.wikipedia.org/wiki/Aurelia_aurita
