Bioluminescence is light produced by a chemical reaction within a living organism.
Bioluminescence is a type of chemi-luminescence, which is simply chemical reaction where light is produced.
Chemistry: The chemical reaction that results in bioluminescence requires two unique chemicals: luciferin, photo protein. Luciferin is the compound that actually produces light. In a chemical reaction, luciferin is called the substrate. The bioluminescent color (yellow in fireflies, greenish in lantern fish) is a result of the arrangement of luciferin molecules.
Some bioluminescent organisms do not synthesize luciferin. Instead, they absorb it through other organisms, either as food or in a symbiotic-relationship .Luciferase is an enzyme, which means a chemical (called a catalyst) that interacts with a substrate to affect the rate of a chemical reaction. The interaction of the luciferase with oxidized (oxygen-added) luciferin creates a byproduct, called oxyluciferin. More importantly, the chemical reaction creates light.
The appearance of bioluminescent light varies greatly, depending on the habitat and organism in which it is found. Most marine bioluminescence, for instance, is expressed in the blue-green part of the visible light spectrum. Also, most marine organisms are sensitive only to blue-green colors. They are physically unable to process yellow, red, or violet colors. Most land organisms also exhibit blue-green bioluminescence.
Few organisms can glow in more than one color. The so-called railroad worm may be the most familiar. The head of the railroad worm glows red, while its body glows green.
Some organisms emit light continuously. Some species of fungi present in decaying wood, for instance, emit a fairly consistent glow, called foxfire.
Green fluorescent protein (GFP) is a valuable “reporter gene.” Reporter genes are chemicals (genes) that biologists attach to other genes they are studying. GFP reporter genes are easily identified and measured, usually by their fluorescence. This allows scientists to trace and monitor the activity of the studied gene its expression in a cell, or its interaction with other chemicals.
Bioluminescence is of great interest to the Navy. When objects move through the ocean, they can cause bioluminescent organisms to flash. This can put projects and people at risk by revealing the presence of submarines.
The reason behind the Dark Freshwater, as their evolution is a slow process and they do not yet have the biodiversity of oceans. Freshwater habitats are often murkier, and deep-water species use other adaptations (such as a catfish’s sensitive “whiskers”) to hunt and defend in the environment.