Bioluminescence

Bioluminesence, common in the submerged caverns and the abyssal depths, is the capability of a creature to be able to naturally emit light. There are a few methods with which this is performed biologically.

Biological Bioluminescence

While this is somewhat of a misnomer, as both methods of bioluminescence can be considered "biological", the form of bioluminescence known as biological bioluminescence is caused by a chemical reaction within the creature's body, caused by naturally-produced chemicals and proteins interacting with one another. This causes the signature glow of many species, and provides sources of light in the darkness of the deep.

Arcane Bioluminescence

Arcane bioluminescence is a version of bioluminescence involving the emission of magical energy. In this form of bioluminescence, it is caused when the creature involved uses magic for some other bodily function. This can be for functions such powering of the digestive system, movement, vision, or many other things. The bioluminescence in these organisms is a byproduct of magical energy given off in the form of light so as to be safely disappated.

Origins

The primary theory as to the source of biological bioluminescence is as a form of anti-toxin on predator species in the ocean. As prey were gaining toxins, predators needed ways to resist these toxins, and these anti-toxins soon became light sources. However, this does not explain bioluminescence in prey species. Others theorise that the origins of bioluminescence comes from digestive enzymes. There is no clear answer as to what the true source of this trait is.

Uses

In the earlier days of civilisation, for those living underwater, creatures with bioluminescence were used as precursory flashlights and lanterns, unhindered by water. These were quickly phased out in favour of newer technology as it became available, however, as qualms arose about the trapping and use of living creatures for the purpose of lights.