The Great Barrier Reef is in reality made up of approximately 2,100 individual reefs and 800 island or coastal reefs.
Despite its massive size – 2,000kms long and covering a total area of 350,000kms – the reef has actually been formed, over millions of years, from the skeletons of tiny marine organisms called coral polyps.
Related to sea anemones and jellyfish, these polyps secrete a hard, outer skeleton made from calcium as a defense against predators and as a means to anchor them.
When they die their skeletons stay behind. New polyps fix themselves to the old skeleton and the cycle starts again with each new generation building on the remains of the previous one.
Coral reefs have been described as the ‘rainforests of the deep’ because of the incredible variety of life that they support. The Great Barrier Reef is made up of 400 species of coral and over 2,000 species of fish ranging in size from tiny cleaner wrasse to huge sharks.
Literally thousands of other creatures ranging from jellyfish to sea turtles, starfish to whales and shellfish to sea birds rely on the reef to support them.
Sunday, October 4, 2009
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