Who can forget that childhood experience with fireflies on a warm summer night? Although the illumination they produce conjures up images of magic and fairy tales, this delightful effect is nothing more than a biological process called bioluminescence, created by a chemical reaction taking place within a living organism’s body. It can be used for a number of purposes, including mating, hunting, camouflage, and communication. Though a firefly sighting may not be all that common in some reaches of the globe, marine bioluminescence occurs on a wide scale, and can be even more ethereal than that of its terrestrial counterparts.

Most people don’t realize that the tendency for creatures to emit light is actually more common in the sea than on land. In fact, marine bioluminescence becomes quite common in the depths of the sea where sunlight does not penetrate, with scientists estimating that as much as 90 percent of deep sea creatures use some form of bioluminescence! Marine biologists exploring great depths in submarines have long told tales of the peculiar twinkling lights they encounter in the deep sea, far from any natural light from above. Marine bioluminescence seems to be common across a diverse group of organisms, from alga that floats high in the water column to many species of deep sea fish and invertebrates.

An enchanting experience with marine bioluminescence can be had by paddling through salt lagoons and bays where comb jellies happen to be migrating. Comb jellies are translucent, gelatinous creatures shaped like little footballs lined with eight rows of longitudinal cilia. Although they are similar to cnidarians, or what are commonly referred to as jellyfish, they are actually ctenophores. These odd, graceful creatures often display bioluminescence, creating beautiful blue-green trails in the water at night as small vessels dip their oars into the sea. If a bioluminescent alga is present, you may get to enjoy the rare thrill of watching your footprints glow as you walk down the beach under the inky blackness of the night sky.

One of the more fascinating examples of marine bioluminescence is found in deep sea anglerfish. These amazing fish have an elongated appendage protruding from their heads complete with a bioluminescent tip. When the illuminated tip flashes, it lures the prey closer to its awaiting jaws under the cover of darkness, and before the victim has a chance to realize it’s a trap, the anglerfish swiftly snaps it up. The anglerfish is just one incredible example of life adapting to its environment in the most clever of ways.

Image via rickyqi