There are times when night surveys on Kuwaiti islands Qaruh and Umm Al-Maradim are filled with anticipation and excitement. There are others, when the heat and humidity in the summer months, while waiting for turtles to emerge from the sea so we can study them, gets to us in ways that sleep is hard to overcome on the soft nesting beaches of these blessed cays. And then, the eyes may begin to play games on us. Out of nowhere, fireflies may appear in the water, on the sand, under our feet as we approach the surf. Another gift from the open seas arrives to wreak havoc on the senses: Our very own, coming to fill the night with wonder, bioluminescent algae.
Charles Darwin noticed bioluminescence in the sea, describing it in his Journal as follows: “While sailing in these latitudes on one very dark night, the sea presented a wonderful and most beautiful spectacle. There was a fresh breeze, and every part of the surface, which during the day is seen as foam, now glowed with a pale light. The vessel drove before her bows two billows of liquid phosphorus, and in her wake she was followed by a milky train. 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 livid flames, was not so utterly obscure, as over the rest of the heavens.”
Bioluminescence is a form of chemiluminescence where light energy is released by a chemical reaction. Fireflies, anglerfish, and other organisms produce the light-emitting pigment luciferin and the enzyme luciferase. Luciferin reacts with oxygen to create light.
Bioluminescence occurs widely among animals, especially in the open sea, including jellyfish, comb jellies, crustaceans, and cephalopod molluscs, in some fungi and bacteria and in various terrestrial invertebrates including insects. Many, perhaps most deep-sea animals produce light. Most marine light-emission is in the blue and green light spectrum. However, some loose-jawed fish emit red and infrared light, and the genus Tomopteris emits yellow light.
The most frequently encountered bioluminescent organisms may be the dinoflagellates present in the surface layers of the sea, which are responsible for the sparkling phosphorescence sometimes seen at night in disturbed water. At least eighteen kinds exhibit luminosity. A different effect is the thousands of square miles of the ocean, which shine with the light produced by bioluminescent bacteria, known as mareel or the milky seas effect.
Non-marine bioluminescence is less widely distributed, the two best-known cases being in fireflies and glowworms. Other invertebrates including insect larvae, annelids and arachnids possess bioluminescent abilities.
It is to wonder why these creatures use bioluminescence. What is the purpose of it? Science teaches us that there is a number of purposes: Counterillumination camouflage, where light in the animal matches its environment and in this way it can hide from predators. Attraction of prey or attraction of mates, as is the case with fireflies. Defense, as the animal distracts its predator with a flash while it escapes to safety. Warning, where the light frightens the adversary to stay away. Communication in some organisms, who need to coordinate their collective movement. Mimicry, which facilitates hunting, or illumination of prey.
Luciferase is also in research for many purposes by modern medicine, even towards potential cancer treatments.
Yet few can describe what this miracle of nature gives to us lucky humans who witness it, right here in Kuwait, on the turtle islands of these magnificent, turquoise, southern territorial waters: The sense of wonder and sheer bliss, this absolute feeling of awe for the honor and the privilege of standing there on the beach, under the starlit sky, feet in green or blue light that the sea has brought, and a million algal fireflies in it headed straight towards us.
Biodiversity East (www.bio-e.org)