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Bioluminescence is the production of light by an organism as the result of a chemiluminescence reaction.

It occurs in a wide variety of organisms, including marine vertebrates and invertebrates, terrestrial arthropods such as fireflies, some fungi, and microorganisms such as some bacteria and dinoflagellates. In some animals, the light is bacteriogenic, produced by symbiotic bacteria such as those from the genus Vibrio; in others, it is autogenic, produced by the animals themselves. Bioluminescence has evolved independently at least 94 times, first emerging in octocorals some 540 million years ago. In most cases, the principal chemical reaction in bioluminescence involves the reaction of a substrate called luciferin and an enzyme, called luciferase. Because these are generic names, luciferins and luciferases are often distinguished by the species or group, e.g. firefly luciferin or cypridina luciferin. In all characterized cases, the enzyme catalyzes the oxidation of the luciferin resulting in excited state oxyluciferin, which is the light emitter of the reaction. Upon their decay to the ground state they emit visible light. In some species, the luciferase requires other cofactors, such as calcium or magnesium ions, and sometimes also the energy-carrying molecule adenosine triphosphate (ATP). In evolution, luciferins vary little: one in particular, coelenterazine, is found in 11 different animal phyla, though in some of these, the animals obtain it through their diet. Bioluminescence has arisen over 40 times in evolutionary history. Both Aristotle and Pliny the Elder mention that damp wood sometimes gives off a glow. Many centuries later Robert Boyle showed that oxygen was involved in the process, in wood, fish, and glowworms. It was not until the late nineteenth century that bioluminescence was properly investigated. The phenomenon is widely distributed among animal groups, especially in marine environments. On land it occurs in fungi, bacteria and some groups of invertebrates, including insects. The uses of bioluminescence by animals include counterillumination camouflage, mimicry of other animals, for example to lure prey, and signaling to other individuals of the same species, such as to attract mates.

Newton Harvey published a monograph, The Nature of Animal Light, summarizing early work on bioluminescence. Bioluminescence attracted the attention of the United States Navy in the Cold War, since submarines in some waters can create a bright enough wake to be detected; a German submarine was sunk in the First World War, having been detected in this way. His research aimed to demonstrate that luciferin, and the enzymes that act on it to produce light, were interchangeable between species, showing that all bioluminescent organisms had a common ancestor.

Bioluminescence is a form of chemiluminescence where light energy is released by a chemical reaction.

Bioluminescence is widely studied amongst species located in the mesopelagic zone, but the benthic zone at mesopelagic depths has remained widely unknown. Unlike the pelagic zone where the emission of light is undisturbed in the open sea, the occurrence of bioluminescence in the benthic zone is less common.

In many animals of the deep sea, including several squid species, bacterial bioluminescence is used for camouflage by counterillumination, in which the animal matches the overhead environmental light as seen from below.

Other possibilities include using bioluminescence to disorient predators or as an aposematic signal to warn of possible toxicity.Grazing copepods release any phytoplankton cells that flash, unharmed; if they were eaten they would make the copepods glow, attracting predators, so the phytoplankton's bioluminescence is defensive.

Bioluminescence is used by a variety of animals to mimic other species.

While most marine bioluminescence is green to blue, some deep sea barbeled dragonfishes in the genera Aristostomias, Pachystomias and Malacosteus emit a red glow.

Luciferase systems are widely used in genetic engineering as reporter genes, and for biomedical research using bioluminescence imaging. Vibrio bacteria symbiose with marine invertebrates such as the Hawaiian bobtail squid (Euprymna scolopes), are key experimental models for bioluminescence.

Quick Facts

• The uses of bioluminescence by animals include counterillumination camouflage, mimicry of other animals, for example to lure prey, and signaling to other individuals of the same species, such as to attract mates.
• In most cases, the principal chemical reaction in bioluminescence involves the reaction of a substrate called luciferin and an enzyme, called luciferase.
• Bioluminescence has evolved independently at least 94 times, first emerging in octocorals some 540 million years ago.
• In evolution, luciferins vary little: one in particular, coelenterazine, is found in 11 different animal phyla, though in some of these, the animals obtain it through their diet.
• In some animals, the light is bacteriogenic, produced by symbiotic bacteria such as those from the genus Vibrio; in others, it is autogenic, produced by the animals themselves.

Source material: Wikipedia - "Bioluminescence". Adapted and summarized for DiscoverScroll. Original contributors are credited through the linked Wikipedia article. Read original on Wikipedia. CC BY-SA 4.0. Changes were made from the original.