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Grades 4-6

Can We Rescue the Reefs?

By Ritu Upadhyay

Under the clear blue sea, bustling communities of ocean creatures live together in brightly colored, wildly stacked structures called coral reefs. These silent, majestic underwater cities are home to 4,000 different species of fish and thousands of plants and animals. For millions of years, marine creatures have lived together in reefs, going about their business in their own little water worlds.

The Great Barrier Reef runs along the east coast of Australia. Scientists come from all over the world to study its exotic plant and animal life.

But danger looms. At an international meeting on coral reefs last month, scientists issued a harsh warning. More than a quarter of the world's reefs have been destroyed by pollution and careless human behavior. Unless drastic measures are taken, the remaining reefs may be dead in 20 years. "We are about to lose them," says Clive Wilkinson of the Coral Reef Monitoring Network.

Precious Underwater Habitats
The destruction of coral reefs, some of which are 21/2 million years old, would have a very serious impact on our oceans. Though coral reefs take up less than 1% of the ocean floor, they are home to 25% of all underwater species. Wiping them out would put thousands of creatures at risk of extinction. It would also destroy one of our planet's most beautiful living treasures.

Not all coral are reef builders. This tubastraea coral is common in shaded areas, under ledges or even under large boulders.

Though it's often mistaken for rock because of its stony texture, coral is actually made up of tiny clear animals called coral polyps. Millions stick together in colonies and form a hard outer shell. The colonies eventually grow together, creating large reefs. When coral die, their skeletons are left behind, and new coral build on top. Reefs grow into complex, mazelike structures with different rooms, hallways, holes and crevices for their inhabitants to live in. Over the years, the ancient Great Barrier Reef off Australia's coast has grown to 1,240 miles long!

This carnation coral resembles a delicate underwater flower in the Red Sea.

Sucking the Life Out of the Reefs
Coral may look and feel tough, but it is extremely sensitive to environmental changes. A major cause of recent reef destruction is the gradual warming of the oceans. The El Niño climate shift in 1998, in particular, heated the seas and did terrible damage to coral reefs.

Warm water causes a deadly situation called coral bleaching. Coral contains tiny algae, or water plants, that give coral its vibrant color. Coral also uses the algae to create its food. This mutually helpful relationship between two beings is called symbiosis (sim-by-oh-sis). At high temperatures, though, coral releases the algae. Without it, not only does coral lose its beautiful color-it dies.

Global warming is believed to be caused by certain polluting gases that trap heat close to the earth's surface. Unless something is done, warns scientist Ove Hoegh-Guldberg, the oceans will grow so warm over the next 20 years that the reefs will be cooking in a "hot soup."

This spotted grouper lives in shallow, clear, warm salt water near coral reefs.

Not Such A Dynamite Idea
While warming may be the biggest threat to coral reefs, it is not the only one. Fishermen do enormous damage. The fish that live in reefs are very valuable as pets and food. To trap these fish, some fishermen employ "blast fishing"-shattering reefs with dynamite. Others drop cyanide poison into the water to stun fish so they are easier to catch. Most of the reefs in the Philippines have been destroyed by such fishing techniques. Pollution from oil slicks, garbage and pesticides has also taken a toll. It messes up the delicate balance among algae, coral and other reef species.

The outlook for reefs is not hopeless, however. Scientists believe reefs can be rescued if governments control pollution and ban practices like blast fishing. Says Wilkinson: "The world's attitude must change."

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