It is the coral polyp skeleton that forms the reef. Long after the coral polyp dies, the corallite remains attached to the reef. Billions of these coral skeletons, many as ancient as the Pyramids, make up some of the oldest, largest and most beautiful structures on Earth. There are many different kinds of corals. These are what gives the coral reef its colourful appearance. Corals feed mostly on plankton. Coral grows in warm climates where there is clear salt water and sunlight. They don't like pollution.

A coral reef is a natural barrier made of the bodies of living and dead coral. It is normally just below the surface of the water.

A coral reef will only flourish where there is:
• clear, fairly shallow water so that the zooxanthellae can get sunlight.
• waves or currents to deliver food and oxygen to the coral polyp
• warm temperatures, ideally 75-85 degrees F.
• salty sea water.

THE GREAT BARRIER REEF
The Great Barrier Reef stretches along the east coast of Queensland in Australia. It is the world's largest coral reef . It is over 2000km (1250 miles) long! It is not a single reef at all. It is made up of over 2900 individual reefs very close to each other.

THE BLUE HOLE

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