Where Is the World’s Largest Reef?
The largest reef in the world is the Great Barrier Reef, located in the Coral Sea off the north east corner of Australia. From Anchor Cay (or island) above the northern tip of Queensland, the reef runs parallel to the mainland at a distance of about 60 miles, to Lady Elliot Island, 1250 miles away to the south. The Great Barrier Reef can be seen from outer space and is the world’s biggest single structure made by living organisms.
The Great Barrier Reef is the world’s largest coral reef system composed of over 2,900 individual reefs and 900 islands stretching for over 2,300 kilometres (1,400 mi) over an area of approximately 344,400 square kilometres (133,000 sq mi). This reef was discovered in 1770 by Captain Cook. He called one of the many navigable passages Providential Channel after he had edged his ship through it to the coast. He named Endeavor Reef, where he ran aground, after the ship itself.
The fantastic coral forms give shelter to a collection of other living creatures, such as fish, crustaceans, worms, molluscs and starfish, of greater variety than can be found anywhere else. Ninety percent of the reef is under water and the remainder is composed of some 900 islands dotted along its length. A few of these islands remain permanently dry and swarm with bird life. They are used also by turtles that come ashore to lay their eggs.
This reef structure is composed of and built by billions of tiny organisms, known as coral polyps. It supports a wide diversity of life and was selected as a World Heritage Site in 1981. CNN labelled it one of the seven natural wonders of the world. The Queensland National Trust named it a state icon of Queensland.
A large part of the reef is protected by the Great Barrier Reef Marine Park, which helps to limit the impact of human use, such as fishing and tourism. Other environmental pressures on the reef and its ecosystem include runoff, climate change accompanied by mass coral bleaching, and cyclic population outbreaks of the crown-of-thorns starfish.
The Great Barrier Reef is a delicately balanced system suffering, from time to time, an upset in its regular routine. Such an upset began in the 1960s with the invasion of the large poison-spined starfish, which is still going on.
Appropriately called “crown-of-thorns”, this starfish has infested some parts of the reef and by feeding on the polyps has ravaged vast areas of living coral. Even so, the reef remains one of the most colorful regions of the world. According to a study published in October 2012 by the Proceedings of the National Academy of Sciences, the reef has lost more than half its coral cover since 1985.
The Great Barrier Reef has long been known to and used by the Aboriginal Australian and Torres Strait Islander peoples, and is an important part of local groups’ cultures and spirituality. The reef is a very popular destination for tourists, especially in the Whitsunday Islands and Cairns regions. Tourism is an important economic activity for the region, generating over AUD$3 billion per year.
A March 2016 report stated that coral bleaching was more widespread than previously thought, seriously affecting the northern parts of the reef as a result of warming ocean temperatures. In March 2017, the journal Nature published a paper showing that huge sections of a 800-kilometre (500 mi) stretch in the northern part of the reef had died in the course of 2016 due to high water temperatures, an event that the authors put down to the effects of global climate change.