Bioluminescence is defined as the generation of light by living organisms. While there are animals on land that depend on this process, lightening bugs for instance, the vast majority of bioluminescent creatures are found in the ocean.
This article from the good folks at Wired gives us a glimpse of the beauty found in these glowing animals that tend to inhabit the deepest parts of the seas. From the article:
Researchers estimate that between 80 and 90 percent of deep-dwelling animals are bioluminous, creating light by mixing the pigment luciferin with luciferase, the enzyme that makes it glow. The light tends to green and blue, colors that travel far in seawater. Glowing helps attract mates, lure prey or confound predators.
There are actually two types of bioluminescence which both work on the principle of mixing pigment. The most predominant, particularly in the ocean, is intracellular. The animal in question generates the light itself in special cells known as photophores. The other type of bioluminescence is extracellular and is made by symbiotic bacteria within the body of the host.
Scientists believe that the primary reason for the evolution of photophores in sea creatures is camouflage. A fish or squid that can mask its silhouette by matching the background of its environment is counterilluminated and will therefore blend in. The fact that most bioluminescent fish have photophores located on their ventral surface lends credence to this theory.
As noted in the article, ocean dwellers also attract prey with glowing lures. A good example of this is the deep sea angler fish with its horrific teeth and glowing lantern. Although the theory of using bioluminescence to attract a mate or mates seems reasonable on the surface, some scientists argue that the same sexy glow that got the girl could also easily attract predators, and get you eaten. Most fascinating of all, at least to me, are the mobile sea creatures that use bioluminescence as a kind of flashlight to illuminate their environment. Notable among these is Histioteuthius, a type of squid with photophores around one eye.
Click over and spend a minute or two marveling at, and learning a little bit about, just a few of these fascinating and beautiful fellow sons and daughters of Neptune. We’re all sailors, after all, but only these guys can light their own way in the dark.
Header: Deiopea Jellyfish via Wired.com