Marvelous Torchbearers of Land and Sea
BY “AWAKE!” CORRESPONDENT IN THE BRITISH ISLES
IS IT not a humbling thought that, long before intelligent man discovered how to make artificial light, multitudes of unthinking creatures on land and in the sea possessed their own tiny but efficient “lanterns”?
Reflect a moment on a few of such creatures that dwell in the perpetual darkness found in ocean deeps. Imagine yourself down there at a depth of, say, 5,000 feet, peering out of the porthole of a bathysphere. What is this tiny light approaching? As it nears you, no doubt to investigate the light from your porthole, you perceive that it is an odd-looking fish. Doing what? Why—fishing! Its fishing rod is twice as long as it is, and dangles out of its mouth. That light? A light organ at the tip of its rod. This creature is known as the angler fish. Another angler fish at about the same depth has its “lure”—a light organ—inside its mouth immediately behind its teeth.
Then there is the lantern fish, so called because—like a passenger ship showing its lighted portholes at night—it has rows of light along each side. Other hunters of the deep have headlights that enable them to cast a beam of light several feet in front of them.
A Mystifying Phenomenon
How, though, can we describe this mysterious phenomenon by which marine creatures (and other living things) can make their own light? Technically, it is called bioluminescence, which is the ability of living organisms to emit light without heat. This is accomplished through the interaction of a chemical known as luciferin and the enzyme luciferase.
Have you ever heard of the “burning seas”? Odd as this term may seem, it refers to several “bays of fire” in and close to Puerto Rico’s “Bahía Fosforescente” (Phosphorescent Bay). The “fire” is caused by untold numbers of tiny creatures called dinoflagellates, which create the illusion of a burning sea by emitting sparks of chemical light. According to the National Geographic Society, this is one of the few places in the world where this phenomenon is found.
One may wonder how it is that such multitudes of these tiny creatures are able to congregate so closely together, despite the scattering influence of tides and winds. The answer lies in the fact that these sheltered bays have very moderate tides, while the sea links with the Caribbean are narrow. Hence, the calm conditions in these bays, together with their vitamin-rich waters, encourage expansion in the numbers of these microorganisms. So, we have these “bays of fire”—that glow in the dark—made possible by tiny creatures that possess their own lighting systems.
Lanterns of Land Creatures
Land creatures, too, have their own tiny lanterns, in some instances a kind of luminosity. Among these are earthworms, centipedes, glowworms and various insects. The glowworms include the remarkable New Zealand glowworms, the larvae of a small fly. Normally they live on the roofs of damp caves, where they weave webs from which are suspended slender threads beaded with sticky mucus. Then, when all is ready, these glowworms turn on their lights, in ones or twos to start, then in unison, operating like a lighthouse—on-off-on-off. For what purpose? To avoid starvation. Insects fly in to investigate the flickering light, get entangled in glowworms’ fishing lines—and are eaten.
Referring to these glowworms, Life Nature Library writes: “A starry universe underground is created on the ceiling above a subterranean river in New Zealand’s Waitomo Caves by the glow of thousands of luminous larvae which trail silken threads down like fishing lines. Insects attracted by the light of the larvae stick on the threads and are then reeled in. The larvae grow into true fireflies.”
The light that these torchbearers give off is said to be without parallel for its coolness, radiating only one part in 80,000 as much heat as that given off by a candle flame of equal brightness. Truly a “cold” light.
Fireflies are possibly the most fascinating of all torchbearers. On warm summer nights, in many areas, they manifest themselves in a fashion that delights the human eye. But who can explain their uncanny ability to operate their flashing mechanisms ultimately in unison? One wonders if, perhaps, they use some kind of code or signal that, unheard and unseen by man, enables them to act thus in chorus. Science has attempted to supply answers, but without satisfying success!
Among other insects that are luminous are the springtails and beetles that may belong either to the click beetle group or the firefly group. Nor must we overlook the so-called railroad worm, related to the firefly group. It has a row of yellow-green lights on each side of its body, as well as—appropriately—a red light on its head!
Luminous Toadstools
Even certain plants have their own tiny lanterns. Notable among these is a species of luminous toadstools, some of which are found on rotting logs in Asian forests. Looking quite ordinary in daylight, at night they emit a mysterious yet beautiful glow, with colors ranging from blue green to yellow orange. So bright is this light that it is said to be as strong as a small night-light.
People who have walked in a forest at night following a heavy shower may well have been puzzled by seeing both live and dead wood giving off a luminous glow. These lights, too, come from fungi growing on timber.
Many Torchbearers in the Seas
Yet, if we could but glimpse a few of the untold multitudes of fascinating torchbearers that dwell in the seas and oceans, we would note that this mysterious built-in ability to emit some degree of light is not confined to any one order of sea creatures but is found in an amazing variety of moving, and unmoving, living things.
How vast, too, is the range in size, each able to give off some degree of light! On occasion, seagoing travelers have noted with excited wonderment tiny sea creatures swarming in glorious profusion, shining and sparkling like millions of little lanterns, lighting the sea to a considerable depth. Among such creatures are some so tiny as to be invisible to the naked eye when not emitting light.
But larger sea animals, such as jellyfish, comb jellies, crustaceans, worms, brittle stars, mollusks, the giant squid, and so on, also emit light. Then, apart from these free-swimming creatures, there are also the sea pens (a kind of polyp) and the luminous hydroids (also polyp-like) that are attached to rocks and piles.
Some deep-sea fish, as we have noted, carry torches on their bellies and sides. Among some—the squid and the shrimp, for instance—definite luminous organs of considerable complexity are visible, containing groups of photogenic cells as well as lenses, reflectors and screens, all working harmoniously together to transform each luminous organ into a beautiful lantern. Whether these light organs are located on the head, along the sides or bellies, in groups or rows (like pearl buttons) or singly, the fish are apparently able to flash them on and off at will.
Not a Different Light
You may wonder: Is this mysterious luminosity or light that so many kinds of living things emit different from other kinds of light? Apparently not, according to Professor E. Newton Harvey, who writes: “It’s colours may be reddish, yellow, green or blue, and its spectrum a continuous short band in these various regions of visible light. No infrared, ultraviolet, or penetrating radiations are produced.”
And how efficient is this light! Man, despite all his ingenuity and twentieth-century wizardry in many spheres of scientific activity, cannot even approach the efficiency of the light emitted by these torchbearers. How so? Because the light or luminosity of these living things is said to be a “cold” light, meaning that while they can create light within their own bodies at will, they can do so without losing more than an infinitesimally tiny fraction of their own body heat. They utilize the needed energy to produce light with such efficiency that almost none of it is converted into heat.
Why So Equipped?
But, for what purposes have some forty different orders of animal life (in the broadest sense), as well as two groups of plants (fungi and bacteria), been fitted with such a fascinating array of lights of varying, scintillating colors? After much research, scientists still cannot be too sure. However, they believe that a main reason is to illuminate their way.
In support of this theory scientists cite the remarkable firefly fish of the Banda Islands in Indonesia. Under each eye this fish has a pocket packed with luminous bacteria. These shine forth so brilliantly that together they look like the twin headlights of a car. When the fish wants to it switches each headlight off by pulling a black fold, like an eyelid, over each pocket. However, it does not seem reasonable to suppose that the emission of light among some marine life, especially the deep-sea fishes, is necessary to light up their way in dark depths where the sunlight never penetrates.
Possibly, also, these creatures use their light when mating, as a signal to the opposite sex, particularly as males and females of each species on land and in the sea are said to have a characteristic flash that helps them to find those of the opposite sex. Indeed, it is thought that some torchbearers use their lanterns only during mating season.
The fireworms of Bermuda may be cited to support this theory. Most of their lives they spend on the seabed. Then, during certain months and after a full moon, mysteriously triggered by some instinct, they rise in swarms to the surface of the sea and put on a brilliant display of flashing lights. Then they mate. But not at any odd time! No, indeed! The act of swarming and mating has to be carried out about fifty-five minutes after sunset!
Also, deep-sea fish apparently use the glowing lights in or close to their mouths, or those dangling in front of them, to attract smaller creatures for food. Possibly, also, these and other deep-sea torchbearers use their light to frighten or warn off predacious animals that fancy them for dinner!
But, really, there are many things about the light of these living creatures that man has yet to learn. The secrets of their “cold” light are still not fully understood, nor can man produce it as efficiently. Truly, the light of these marvelous living torchbearers of land and sea is evidence of a Wonderful Creator.