BIOLUMINESCENCE (scientific definition)

BIOLUMINESCENCE

            Light from fireflies and other living things is called bioluminescence. There are many bioluminescent things in nature; plants, animals, and bacteria.

            The glowing plants include only a few kinds, such as certain toadstools and molds. But animals that light up are more numerous; they range from tiny one-celled sea creatures to sponges, clams, worms, and insects. The most numerous glowing forms of life are found in the salt water of oceans. The most familiar forms are found on the land; fireflies, glowworms, and fox fire fungus.

            Bioluminescence is called “cold” light to distinguish it from incandescence, or heat giving light.

            Bioluminescence can also be used as a tool by researchers to learn more about the ocean and its mysteries. Edie Widder, a scientist who specializes in bioluminescence, was with a group attempting to film the giant squid for the first time. She suspected that the giant squid would be lured to a bioluminescent light attached to a fake squid—not because it wanted to eat the small fake squid, but because it’s flashing light "burglar alarm" could mean that there was larger prey in the vicinity. Her theory proved right. A live giant squid was captured for the first time on film in 2012!

            The substance that gives off light in living things is called luciferin. This “glowing” chemical was named in 1887 by one of the earliest scientists to study living light, Raphael Dubois, of France. Dubois named this chemical substance “luciferin” meaning “light bearer.” Through his experiments using the glowing fluid taken from a clam, Dubois found that the light was caused by a team of chemicals working together. Luciferin would not light up except in the presence of a second chemical, which Dubois called “luciferase.”

            Scientists have since learned that living light is produced when luciferin and oxygen combine in the process of luciferase.

            In some cases, the function of the light seems obvious. Marine fireworms use glowing light as mating signals. During the mating season, the female fireworms come up from deep waters to the surface of the sea and glow. Seeing the, the males join the females. A mating dance follows and then both sexes release their reproductive cells into the water.

            Bulblike organs, called photophores, on the bodies of many deep-sea fish attract mates or prey and illuminate the search for them in the darkness of the ocean depths. Some luminescent fish zigzag through the water with lights flashing to confuse predators and escape being eaten.

            Much remains to be learned about the chemistry of bioluminescence. Perhaps some day enough will be known to produce this cold light for everyday use instead of the energy-wasting electric light we use now.

Sources: The New Book Of Knowledge, Volume 2 & http://ocean.si.edu/bioluminescence