A Natural Wonder of the World

Reef

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Approximately 500 million years ago the world's first coral reefs occurred. The Great Barrier Reef is 500,000 years old. The reefs structure is approximately 8,000 years old. Most reefs form on hard surfaces such as on the base of an old reef that had died due to low waters or possibly the edge of a rocky island. Reefs change as they grow and can become an atoll, a platform reef, a fringing reef, or a barrier reef.

• Atoll- A reef grows in a pyramid shape, like a volcano and a lagoon forms in the center of the surrounding reef. Smaller reefs grow within the lagoon.

• Platform Reef- The coral reaches the surface of the sea, branches out, and grows horizontally. Flat structures form right below the water surface.

• Fringing Reef- The coral grows away from, but very close to the mainland or island coast.

• Barrier Reef- The coral grows farther out from the mainland in an upward direction. The area between the coral and land will sometimes create a lagoon.