The Colorful World of Coral Reefs
BY AWAKE! CORRESPONDENT IN PAPUA NEW GUINEA
CORAL reefs line virtually the entire coast of Papua New Guinea. In bygone days sailors viewed them as little more than a hazard. But to those who have explored the waters surrounding them, coral reefs are the gateway to a world of great beauty, color, and tranquillity—an underwater kaleidoscope!
Attempting to capture this underwater world on film is a real challenge. For one thing, objects under water appear to be located at about three quarters of their actual distance; focusing is therefore difficult. Water absorbs, scatters, and refracts light. Colors can also vary greatly according to the weather, the sun’s angle, the presence of algae and plankton, the water’s depth, and the type and color of the sea bottom. To top it all off, the water, the subject being photographed, and the photographer himself are in constant motion!
Even so, some photographers have had a measure of success in this regard. The pictures you see here have been taken during underwater excursions. Let us introduce you to four of the fascinating creatures shot on film beneath the waves.
Photo 1 shows a beautiful denizen of the deep called the tiger cowry (Cypraea tigris). This name is unusual in view of the fact that its exquisitely patterned shell is spotted, not striped. The tiger cowry is at home here, since it feeds on coral and sponges. The ancient Chinese were so impressed by it that they used its shell as a form of currency. Here in Papua New Guinea, cowry shells are still used as small change in some native markets. For the most part, though, local residents collect them simply for their polished beauty.
Photo 2 is the beautifully colored tube worm (Spirobranchus giganteus). It may live on dead coral or may burrow into living coral. At rest, it looks like a flower. But when hungry, it twirls its tentacles to form a “net” to snag passing morsels of food quickly. With its feathery tentacles in motion, it looks like a row of miniature dancers waving their fans. This specimen was only three eighths of an inch [10 mm] wide. But the photographer must be careful not to make any sudden movement. At the first indication of danger, in the blink of an eye, these dainty miniatures snap back into their skeleton home.
Photo 3 is the sponge. It bears little resemblance to the synthetic type that floats in your bathtub. A sponge is actually a living animal, not a plant. It is a porous mass of cells that function together in a most peculiar way. The book The Undersea says that the cells of sponges “are neither closely organized nor interdependent. Thus, if a living sponge is torn into pieces, each part eventually forms a new sponge. Even if the individual cells are separated, they wriggle along like amoebas until they come together and build up into whole sponges again.”
Unlike a plant, which manufactures its own food, the sponge “hunts” for its food. It draws in surrounding water and filters it for organic material. Like any other animal, it digests its food and expels its wastes. You will find sponges attached to rocks or to shells on the seabed.
Finally, in photo 4 there is the lowly clam. It is sedentary and can easily be found in coral rocks or simply lying on the seabed. Most feed by filtering plankton out of the water. The clam is called a bivalve mollusk because it has two shells, or valves. These are held together by a ligament and are opened and closed by two powerful muscles. When a clam needs to move, it opens up and its fleshy foot emerges a bit. But should an enemy approach, it retreats into its shell and ‘clams up’!
These pictures give but a glimpse of the glorious sights that can be seen in the coral seas—yet another place where Jehovah’s creative wisdom is on display.—Romans 1:20.
[Pictures on page 16, 17]
1. The tiger cowry is still used as money
2. These “flowers” are really tube worms
3. The sponge is an animal, not a plant
4. The clam feeds on plankton (mouth shown)