The Great Barrier Reef is a site of remarkable variety and beauty on the north-east coast of Australia. It the world's most extensive stretch of coral reef and is probably the richest area in terms of faunal diversity in the world. Its great diversity reflects the maturity of an ecosystem which has evolved over millions of years on the north-east continental shelf of Australia. The site contains a huge diversity of species including over 1,500 species of fish, about 360 species of hard coral, 5,000 species of mollusc, and more than 175 species of bird, plus a great diversity of sponges, anemones, marine worms and crustaceans, among others.
The reef system, extending to Papua New Guinea, the reef comprises some 2900 individual reefs of all sizes and shapes covering more than 20,000 km2, including 760 fringing reefs, which range in size from under 1ha to over 10,000 ha and vary in shape to provide the most spectacular marine scenery on Earth. There are approximately 600 continental islands including many with towering forests and freshwater streams, and some 300 coral cays and unvegetated sand cays. A rich variety of landscapes and seascapes, including rugged mountains with dense and diverse vegetation and adjacent fringing reefs, provide spectacular scenery.
The form and structure of the individual reefs show great variety. Two main classes may be defined: platform or patch reefs, resulting from radial growth; and wall reefs, resulting from elongated growth, often in areas of strong water currents. There are also many fringing reefs where the reef growth is established on subtidal rock of the mainland coast or continental islands.
The site includes major feeding grounds for the endangered dugong and nesting grounds of world significance for two endangered species of marine turtle, the green and the loggerhead, as well as habitat for four other species of marine turtle; given the severe pressures being placed on these species elsewhere, the Great Barrier Reef may be their last secure stronghold. It is also an important breeding area for humpback and other whale species.
A wide range of fleshy algae occurs, many of which are small and inconspicuous but which are highly productive and are heavily grazed by turtles, fish, molluscs and sea urchins. In addition, algae are an important component of reef building processes. 15 species of seagrass grow throughout the reef area forming over 3,000 km2 of seagrass meadows and providing an important food source for grazing animals, such as dugongs.
The Great Barrier Reef, and in particular the northern sector, is important in the historic and contemporary culture of the Aboriginal and Torres Strait Islander groups of the coastal areas of north-east Australia. This contemporary use of and association with the Marine Park plays an important role in the maintenance of their cultures and there is a strong spiritual connection with the ocean and its inhabitants.
9. Great Barrier Reef, Australia
"..The Great Barrier Reef is an icon, and we want to know what we can do to save it" - Dr Scarla Weeks