The Great Barrier Reef http://www.gbrmpa.gov.au/, off the east coast of Australia, is one of the wonders of the natural world – it is the world’s largest coral reef ecosystem and the only living organic collective visible from Earth’s orbit.
Starting just south of the Tropic of Capricorn between Gladstone and Bundaberg, the Great Barrier Reef goes all the way up to the Torres Strait near the coast of Papua New Guinea. The outer reef lies along the edge of the Australian continental shelf. It is the most extensive reef system in the world, stretching 2,300 kilometres along the east coast of Queensland in the Pacific Ocean.
Named as a World Heritage Area in 1981, the Great Barrier Reef was listed for being an outstanding example of a reef system, representing the major stages in the earth’s evolutionary history; significant ongoing ecological and biological processes; superlative natural phenomena; and important and significant habitats for in situ conservation of biological diversity.
At 344,400km2, the reef is bigger than New Zealand, larger than the total area of the United Kingdom and Ireland combined, and roughly equal to the size of Japan.
The Reef includes a range of fascinating geographic forms ranging from fringing coastal reefs and lagoons, outer reefs and the open ocean, islands, estuaries and coastal beaches.
There are about 2,900 separate reefs and 918 islands to explore. Of these islands, 618 are continental islands and 300 are coral cays, 230 of which have permanent vegetation. The remainder are beautiful small sand cays that shift in response to winds, waves and currents.
The coral rock that forms the base for the modern reef is between 20m and 500m thick in places, and mostly about two million years old – although in some northern parts, the reef’s foundations date back more than 18 million years.
Corals make up the various reefs and cays and are the basis for the great variety of sea and animal life in the Reef. Coral consists of individual coral polyps – tiny live creatures which join together to form colonies. Each polyp lives inside a shell of aragonite, a type of calcium carbonate which is the hard shell we recognise as coral. The polyps join together to create forests of coloured coral in interesting fan, antler, brain and plate shapes.
The ideal environment for coral is shallow warm water where there is a lot of water movement, plenty of light, where the water is salty and low in nutrients. There are many different types of coral, some are slow growing and live to be hundreds of years old, others are faster growing. The colours of coral are created by algae - live coral is coloured whilst dead coral is white.
The coral has, over the years, brought many ships to grief including Captain James Cook’s ship Endeavour. One of the most famous wrecks is that of the HMS Pandora, which foundered in 1791. The Queensland Museum has been leading archaeological digs to the Pandora since 1983 and its most recent was completed in February 1999. There are 30 shipwreck sites known in the marine park.
The islands and coral cays support around 215 bird species, many of which have breeding colonies there. Reef herons, osprey, pelicans, frigate birds, sea eagles and shearwaters are among the numerous sea birds that have been recorded. Various reef islands are inhabited by koalas, echidnas, possums and fruit bats. The island reptiles and amphibians are represented by seven frog species, nine snakes and 31 lizard species.
The reef also contains nesting grounds of world significance for six of the world’s seven species of marine turtles. All are regarded as endangered. During nesting season (from November to February) these fascinating animals lay their eggs on many reef islands and some parts of the coast.
The extensive seagrass beds are an important feeding ground for the dugong or ‘seacow’, a fascinating mammal species internationally listed as endangered.
The warm waters of the reef are also a whale breeding area. Between August and November every year Humpback whales make their way up the coast from the Antarctic to give birth to their young. Visitors can join one of the whale watching cruises for an experience of a lifetime. Both Antarctic and Dwarf Minke whales are also found in Great Barrier Reef waters.
The many diving and snorkelling opportunities provide visitors with the best way of getting close to the reef’s many wonders. Tour operators offer accredited dive courses, introductory reef dives and for the experienced, extended dive charters incorporating night or guided ecology dives.
The Great Barrier Reef is one of 28 nominees in the New 7 Wonders of Nature campaign – a global search to recognise the seven most important natural sites in the world as voted by the public. To cast your vote for the Great Barrier Reef go to www.n7w.com.