"Bioluminescence is a specific form of chemiluminescence, which is a phenomenon in which the chemical energy that is produced in a chemical reaction is converted into radiant energy. In bioluminescence, the reaction is a natural function that originates in a living organism. It should not be confused with fluorescence or phosphorescence, neither of which involves a chemical reaction. Instead, fluorescence and phosphorescence are both products of spontaneous emission, in which photons are absorbed and then later reemitted.
"Bioluminescence also involves the emission of photons, but this is caused by the oxidation of a light-emitting compound called luciferin. When the oxidized luciferin, or oxyluciferin, returns to its ground state, its excess energy is released as a photon. Unlike the light bulb, in which electrical energy is converted into light and some of the energy is lost in the form of heat, a bioluminescent reaction is 100 percent efficient, converting all of the emitted energy into light. Because there is no heat released, bioluminescence is also known as 'cold light.'”
from Ghayourmanesh S. 2013. Bioluminescence. Ebsco discovery research starters. [accessed 2018 Oct 25]. https://search.ebscohost.com/login.aspx?direct=true&db=ers&AN=89551619&site=eds-live&scope=site.
Luciferin
Oxyluciferin
Luciferase
Annelids
Arthropods
Ctenophores
Dinoflagellates