Bioluminescence

BIOLUMINESCENCE is when LIVING ORGANISMS produce their own LIGHT. From fireflies on land to glowing plankton in the ocean. Especially common in the OCEAN — where about 75% of mid-water animals can produce light. The deep sea, with no sunlight, is filled with living lights. Each species uses bioluminescence for different purposes: hunting, defense, mating, communication, camouflage.

How it works. A chemical called LUCIFERIN reacts with oxygen, catalyzed by an enzyme called LUCIFERASE. The reaction produces light with very little heat (cold light — much more efficient than incandescent bulbs). Some animals make their own luciferin; others get it from prey. Many organisms control their lights — turning them on and off, sometimes flashing in patterns.

Examples. FIREFLIES on land flash to attract mates. JELLYFISH glow to startle predators. ANGLER FISH lure prey. DEEP SEA SQUID can squirt glowing ink to confuse attackers. FISH on the bottom of squid's lit body counter-illuminate to match the dim light from above (camouflage). Some BACTERIA glow when concentrated. SCIENCE applications: green fluorescent protein (GFP) from jellyfish is used in research labs worldwide to tag genes and track cells.

Bioluminescence shows life's extraordinary creativity. In darkness, animals invented their own light. The ocean glows in ways we are still discovering.