For the most part Bioluminescence is also absent in fresh water. In this chemical reaction first luciferin and oxygen bind. Then luciferase acts upon or catalyzes luciferin to produce light, oxyluciferin . Luciferin , which binds to oxygen to began the cycle, is obtained in organisms in one of two ways. Either it is eaten and eventually gets to the organism by the food chain or the organism synthesizes it on their own.
Bioluminescence plays an important role in the ecology of the land and most importantly the ocean.
In the deep oceans Bioluminescence is often the only source of light. There are three main ways the light of bioluminescence is used. They are offense, defense, and communication. Defensively, the light is used by the organisms to startle and divert predators. To do this the organism uses flashes of it's light.