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Coral reefs are among the oldest and most primitive forms of life, dating back at least 500 million years.Today,the Great Barrier Reef is the largest reef system in the world, covering 2000 km from Bundaberg to the tip of Cape York and an area of approximately 350,000 sq kms. Between the outer edges of the reef and the mainland there are more than 2,000 islands and almost 3000 separate reefs, of differing types. On Islands with a fringing reef coral can be viewed at close hand, although the best coral is on the outer reef about 50 km from the mainland.
by JosephRichards
Coral reefs are among the oldest and most primitive forms of life, dating back at least 500 million years.Today,the Great Barrier Reef is the largest reef system in the world, covering 2000 km from Bundaberg to the tip of Cape York and an area of approximately 350,000 sq kms. Between the outer edges of the reef and the mainland there are more than 2,000 islands and almost 3000 separate reefs, of differing types. On Islands with a fringing reef coral can be viewed at close hand, although the best coral is on the outer reef about 50 km from the mainland.
The Great Barrier Reef consists of thousands of separate reefs. It is fairly young since most of it formed after the sea level rose at the end of the last Ice Age. Coral cannot grow above the water line or below 30 metres therefore its growth id dependent on the sea level. When the sea level rises old coral turns to limestone and eventually new coral will build, thus forming a barrier reef. An outer reef system corresponds with Queenslands continental shelf. Reef systems nearer the mainland correspond with submerged hills.
18,000 years ago, during the last Ice Age, the waters were so low they exposed a range of forested hills. Coral began to grow in the shallow waters of the continental shelf. Around 9,000 years ago, the water level began to rise and submerged the hills. Coral then began to grow in new places. Since then, coral has formed walls on the continental shelf causing an array of fringing and platform reefs, coral cays and lagoons to form around the former hills.
More than 2000 species of fish and innumerable species of hard and soft coral are found in the waters of Great Barrier Reef. The diversity of life forms is extraordinary and there is also a huge array of invertebrates such as the graceful sea slug, 12 species of sea grasses and 500 types of algae. Also in the water you can find Manta rays, potato Cod, Great White Sharks, Coral Groupers, Giant Clams, Moray eels and Clown anemone fish.
To safely breed and raise their young, tropical birds tend to gravitate on the reef islands. The island is free of mainland predators which makes it a more friendly environment for these tropical birds. Gulls, gannets, frigate birds, and shearwaters are just some of the wonderfully coloured birds you can find here.
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