The Great Barrier Reef is the largest coral reef in the world. It is located off the shores of northeastern Australia, framing the Queensland coastline for 2300 kilometers from Bamaga to Bundaberg, Queensland. The Great Barrier reef occupies an area of more than 344,000 square kilometers. Its width ranges between 60 and 250 kilometers. The Great Barrier Reef is a collection of more than 2,900 coral reefs, 600 continental islands (many with their own fringing reefs), 300 coral cays and thousands of species making it one of the world's most complex and diverse ecosystems.
The Great Barrier Reef is protected by the Australian Government's Great Barrier Reef Marine Park Authority, established in 1975. In 1981, the Great Barrier Reef was designated as a World Heritage Site and as such is protected by the World Heritage Convention, an international organization whose aims are to protect and conserve designated sites for all time.
The term climate is normally associated with habitats above ground. But reefs, like terrestrial habitats, have climates too and survive within a range of temperatures and water conditions. Around the world, reefs generally occur only where temperatures remain above 64° Fahrenheit most of the time. This means that they are usually located in the tropics, within 30° north and south of the equator. The Great Barrier Reef benefits from warm water in the South-West Pacific Ocean which keeps its temperatures suitable for supporting reef life.
The animals of the Great Barrier Reef include some 1500 species of marine fish, 360 species of hard corals, between 5000 and 8000 species of mollusks, 600 species of echinoderms, 17 species of sea snakes, 30 species of whales and dolphins, 6 species of marine turtles, 22 species of seabirds and 32 species of shorebirds which breed on the reef's many small islands.
The species diversity and complex interactions that characterize the wildlife of the Great Barrier Reef reflect a mature ecosystem. The evolution of the Great Barrier Reef began after Australia broke away from the Gondwana land mass 65 million years ago. Australia drifted northward to warmer tropical waters—waters that could support the formation of coral reefs. By 18 million years ago, it is thought that the northern parts of the Great Barrier Reef started to form, spreading gradually southward.