Bioluminescence Basic Organisms

Bioluminescence

Bioluminescence is a form of chemiluminescence, which is the production of visible light by a chemical reaction. When this kind of reaction occurs in living organisms, the process is called bioluminescence.

 It is familiar to most of us as the process that causes fireflies to glow. Some of us may also have seen “foxfire,” which is caused by bioluminescence in fungi growing on wood.

Bioluminescence is relatively rare in terrestrial ecosystems, but is much more common in the marine environment. Marine organisms producing bioluminescence include bacteria, algae, cnidaria, annelids, crustaceans, and fishes.

The production of light in bioluminescent organisms results from the conversion of chemical energy to light energy. The energy for bioluminescent reactions is typically provided by an exothermic chemical reaction. Bioluminescence typically requires at least three components: a light-emitting organic molecule known as a luciferin; a source of oxygen (may be O2 , but could also be hydrogen peroxide or a similar compound); and a protein catalyst known as a luciferase. In some organisms, these three components are bound together in a complex called a photoprotein.

Light production may be triggered by the presence of ions (often calcium) or other chemicals. Some bioluminescent systems also contain a fluorescent protein that absorbs the light energy produced by the photoprotein, and reemits this energy as light at a longer wavelength. Several different luciferins have been found in marine organisms, suggesting that bioluminescence may have evolved many times in the sea among different taxonomic groups. Despite these differences, most marine bioluminescence is green to blue in color. These colors travel farther through seawater than warmer colors. In fact, most marine organisms are sensitive only to blue light.

BIOLUMINESCENT ORGANISMS

 

KILLUMINATION

 

Hundreds of meters down in deep, pitch-black ocean waters, monstrous-looking ANGLERFISH wave about bioluminescent lures, called esca, to temp prey into swimming within striking distance. Like fireflies, these common deepwater fish may use the lighting effects in mate selection, as well.

The anglerfish is unusual among bioluminescent creatures in that it does not make its own light chemically; rather, it hosts colonies of symbiotic, light-producing bacteria in its fleshy lure.

 

 

FLYING WITH FIRE

 

The power to make its own light distinguishes the life—and death—of the familiar firefly. Also commonly called lightning bugs, these species have developed unique call-and-response patterns of flashes between courting, airborne males and the females that watch from leafy perches. But danger lurks in this bioluminescent Morse code: Female fireflies in the Photuris genus, for example, mimic the flash responses of females in the Photinus genus, tricking love-seeking, smaller Photinus males into becoming a light meal.

The firefly enzyme Luciferase catalyzes the formation of a Luciferin and ATP complex known as Luciferyl adenylate. This complex is oxidized by oxygen, leading to the production of a cycle peroxide that eventually becomes high-energy Oxyluciferin. The oxyluciferin is initially in an excited state; by relaxing back to the ground state, energy is released and light is emitted.

luciferin + ATP → luciferyl adenylate + PPi
luciferyl adenylate + O2 → oxyluciferin + AMP + Light.

 

GELATINOUS GLOW

 

Comb jellies, technically known as ctenophores, are a phylum of seafaring organism characterized by their use of small hairs, or cilia, for aquatic locomotion. Almost all of these blobby beings also bioluminesce, and they provide yet another example of defensive lighting with so-called "sacrificial tags". Chunks of ctenophores bitten off by predators will keep glowing in the predator's translucent guts, highlighting the gobbler in the ocean's gloom. 

 

EFFULGENT FUNGI

 

Mushrooms gleam in forests all over the world, from the Mycena lucentipes species seen here, described in Brazil last year, to the honey and jack o' lantern mushrooms that emit a greenish "fox fire" glow in woodlands. Researchers have now documented more than 70 species of bioluminescent fungi, although the exact purpose of the 'shrooms' bioluminescence remains mysterious. For species in which just the spore-containing cap shines, the glow may help get the attention of nocturnal bugs that then aid in spore dispersal, similar to brightly colored fruit that draws in frugivores to spread pollen and seeds. Other species with radiant mycelia, or threadlike, vegetative parts, may deploy bioluminescence defensively to attract the predators of the insects that dine on the mushrooms

 

BLUE TIDE

 

Much of the brightness that is observed on the surface of the oceans is due to the bioluminescence of certain species of dinoflagellates, or unicellular algae, and this bioluminescence accounts for many of the recorded observations that have described the apparent "phosphorescence" of the sea. Dinoflagellates are very sensitive to motion induced by ships or fish, and respond with rapid and brilliant flashes, thus causing the glow that is sometimes seen in the wake of a ship. The luciferin in these instances is a tetrapyrrole containing four five-member rings of one nitrogen and four carbons, and its oxidation , catalyzed by dinoflagellate luciferase, results in blue-green light centered at about 470 nanometers (1.85 × 10 ⁻⁵ inches)

PHOTONIC CAMOUFLAGE 

Even in ocean depths where sunlight barely penetrates, the faint silhouette that a fish throws to predators beneath it in the water column can make it an easy target. Accordingly, many fish, crustaceans and squid have developed bioluminescent "counterillumination" abilities. Light-emitting organs called photophores line their undersides. These creatures can adjust the light output of these organs to match the light their eyes receive from above to help eliminate their shadows. The hatchetfish, shown here, is one such species equipped with an underbody that lights up to camouflage it from hungry eyes below.

 

SPARKLING SLIME

 

Dozens of earthworm species from all over the world can secrete a glowing slime, thought to startle predators. This particular worm, Diplocardia longa, is found in sandy soils in southern Georgia in the U.S. and can stretch to over half a meter in length.