Some species of jellyfish can produce light in their bodies, known as bioluminescence. This process is a chemical reaction that produces a blue-colored light in most species notably Aequorea Victoria. This is how the chemical process of producing bioluminescence works: There are two types of chemicals in the bodies of bioluminescent jellyfish- luciferin and luciferinase. When triggered, the chemical luciferin gets oxidized by the action of the chemical luciferinase . When these two react, the result of the reaction is a photoprotein. This photoprotein is the cause of the bluish glow that the bioluminescent jellyfish acquire.
Aequorea Victoria is one such jellyfish that acquires a blue colored bioluminescence. It is mostly found in the Pacific Ocean off the western coastline of North America. This jellyfish is almost entirely colorless and transparent. Their bell has about 150 tentacles on the margins of its body and they are uneven in length. The tentacles have a large number of nematocysts lining their sides. This is mostly used to capture and ingest food. However, the venom of this jellyfish is so mils that it does not have any noticeable effect on humans. This jellyfish mostly feeds on soft-bodied organisms including, but not limited to, some crustacean zooplankton such as copepods, crab zoŽals, barnacle nauplii & other larval planktonic organisms.
On the other hand, some jellyfish, especially of the hydrozoa class, have an additional protein known as green fluorescent protein, which takes the blue light and shifts it to a green color. Aequorea macrodactyla is one such jellyfish that acquires a green colored bioluminescence. This green bioluminescence is supposed to be brighter than its blue counterpart. The identification of the green fluorescent protein happened only in 1961. Since then, a lot of progress has been made in the study of green fluorescent protein.
Jellyfish are extremely simple creatures and do not have eyes. They do not need eyesight to capture and eat their food. Also, since they cannot see, the bioluminescence cannot be required for the purpose of recognizing each other, like some other species of fish. So, what is the purpose of this bioluminescence in jellyfish? There are two important reasons for the bioluminescence in a jellyfish:
The most important reason is to scare off any potential predator. A bioluminescent jellyfish produces light when it is touched. A touch is considered a sign of threat and an immediate chemical reaction gets triggered which results in the production of the photoprotein which gives out the bioluminescence. This helps to startle the potential predator and gives the jellyfish a chance to escape. On the other hand, the light also puts the potential predator at the risk of being detected by its predator and it quickly slinks away to avoid detection.
The bioluminescence of a jellyfish also plays an important role in the mating procedure of the jellyfish. On reaching sexual maturity, a bioluminescent jellyfish uses its bioluminescence to attract a mate.
It is important to remember that only some parts of a bioluminescent jellyfish have the chemicals required to produce bioluminescence.