Bioluminescence is a light produced by a living organism as a result of a chemical reaction. This reaction almost always occurs within the organism itself, although there are some exceptions. For example, there is a species of shrimp that, when threatened, emits an ink-like cloud of bioluminescence. Certain organisms, like the anglerfish, actually contain other organisms, usually bacteria, that create bioluminescent light for them.
There are two main types of compounds involved in every bioluminescence reaction: a luciferin and a luciferase. The luciferase, from the latin “light-bearer”, acts as a catalyst, making it possible for the reaction to occur at all. The luciferin, from the latin “light-bringer”, is what actually produces the light. When oxidized, the luciferin creates photons, which are particles that we perceive as light. Many different compounds can act as a luciferin or a luciferase in these types of reactions, since luciferin and luciferase are not specific substances. ATP (adenosine triphosphate), the compound that stores chemical energy in cells, is also sometimes required to create bioluminescence.
Bioluminescence is a subtype of luminescent light called chemiluminescence. Chemiluminescence is light that occurs as a result of a chemical reaction. Luminescent light is light that, unlike incandescent light, does not produce heat. For this reason, it is also sometimes called “cold light”.
Bioluminescence can occur in many different types of organisms, although it is especially common in ocean-dwelling ones. In fact, it is so common that Dr. Edith Widder, a respected marine biologist and oceanographer, claims that, in the ocean, “bioluminescence is the rule, not the exception”. Scientists believe that 80 to 90% of deep sea organisms could be bioluminescent. Take a look at the slideshow below to see some examples of bioluminescent organisms.
Bioluminescence is an extremely useful ability. Some organisms, like the anglerfish, use bioluminescence to lure prey, while others may use it to avoid becoming prey. Potential prey can use bioluminescence to blend into their environment or attract other organisms to fend off their attacker, among other things. Bioluminescence can also be used a form of communication between organisms; for example, certain types of crustaceans have been found to use bioluminescence to attract mates.
Examples of Bioluminescence
A Brief History
"Some things, though they are not in their nature fire, nor any species of fire, yet seem to produce light" Aristotle, 4th century BCE
"As far as the eye reached, the crest of every wave was bright, and the sky above the horizon, from the reflected glare of these vivid flames, was not so utterly obscure, as over the rest of the heavens." Charles Darwin, 1833
Bioluminescence has long been a part of human history. Many ancient civilizations were aware of it, and it has even made appearances in the legends and folklore of various cultures.
While the earliest mentions of bioluminescence come from ancient Eastern civilizations, the first known detailed description of bioluminescence came from the Greek philosopher Aristotle in the 4th century BCE, in his treatise De Anima (On the Soul). Although Aristotle was not right about everything, he did correctly recognize bioluminescence as a “cold light”. Later descriptions came from the Romans Pliny the Elder and Pliny the Younger in the first century CE.
The Dark Ages weren’t a great time for science, and so there aren’t many observations of bioluminescence from that time period. However, as explorers began crossing the oceans, descriptions of bioluminescence began to pop up again. Christopher Columbus and Sir Francis Drake both took note of luminescence in the ocean, as well as in some other creatures they encountered in their journeys. A mention of bioluminescence even found its way into Shakespeare’s Hamlet.
By 1667, scientist Robert Boyle had noted that air (specifically oxygen, as scientists would later discover) is required for bioluminescence to occur. In the 1900’s, pharmacologist Raphaël Dubois extracted and named the two main components of a bioluminescence reaction: the luciferin and luciferase.
In the 18th and 19th century, some of the first bioluminescence experiments on various organisms were taking place. In the 1830s, Charles Darwin observed and pondered the mysteries of bioluminescence (which he called phosphorescence) during his voyage on the Beagle.
In the early 20th century, the zoologist and inventor E. Newton Harvey did a great deal of research on bioluminescence. In 1922, Harvey actually invented a heat-less reading lamp using the luciferins of dead crustaceans.