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The Great Barrier Reef is the world's largest coral reef system, [1] [2] composed of over 2,900 individual reefs [3] 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). [4] [5] The reef is located in the Coral Sea, off the coast of Queensland, Australia ...
- 34,870,000 ha (86,200,000 acres)
- 1981 (5th Session)
- Natural: vii, viii, ix, x
- Off the east coast of the Queensland mainland, Australia
Oct 19, 2023 · Learn about the biodiversity, threats, and conservation of the Great Barrier Reef, the world's largest coral reef system. Find out how climate change, pollution, and other factors affect its health and how people are working to protect it.
- Overview
- Geography
Great Barrier Reef, complex of coral reefs, shoals, and islets in the Pacific Ocean off the northeastern coast of Australia that is the longest and largest reef complex in the world. The Great Barrier Reef extends in roughly a northwest-southeast direction for more than 1,250 miles (2,000 km), at an offshore distance ranging from 10 to 100 miles (1...
The reef actually consists of some 2,100 individual reefs and some 800 fringing reefs (formed around islands or bordering coastlines). Many are dry or barely awash at low tide; some have islands of coral sand, or cays; and others fringe high islands or the mainland coast. In spite of this variety, the reefs share a common origin: each has been formed, over millions of years, from the skeletons and skeletal waste of a mass of living marine organisms. The “bricks” in the reef framework are formed by the calcareous remains of the tiny creatures known as coral polyps and hydrocorals, while the “cement” that binds these remains together is formed in large part by coralline algae and bryozoans. The interstices of this framework have been filled in by vast quantities of skeletal waste produced by the pounding of the waves and the depredations of boring organisms.
European exploration of the reef began in 1770, when the British explorer Capt. James Cook ran his ship aground on it. The work of charting channels and passages through the maze of reefs, begun by Cook, continued during the 19th century. The Great Barrier Reef Expedition of 1928–29 contributed important knowledge about coral physiology and the ecology of coral reefs. A modern laboratory on Heron Island continues scientific investigations, and several studies have been undertaken in other areas.
The reef has risen on the shallow shelf fringing the Australian continent, in warm waters that have enabled the corals to flourish (they cannot exist where average temperatures fall below 70 °F [21 °C]). Borings have established that reefs were growing on the continental shelf as early as the Miocene Epoch (23.0 million to 5.3 million years ago). Subsidence of the continental shelf has proceeded, with some reversals, since the early Miocene.
Britannica Quiz
Wonders of the World Quiz
The water environment of the Great Barrier Reef is formed by the surface water layer of the southwestern Pacific Ocean. The reef waters show little seasonal variation: surface-water temperature is high, ranging from 70 to 100 °F (21 to 38 °C). The waters are generally crystal-clear, with submarine features clearly visible at depths of 100 feet (30 metres).
- The Editors of Encyclopaedia Britannica
Learn about the remarkable variety and beauty of the Great Barrier Reef, the world's largest coral reef ecosystem with 400 types of coral and 1,500 species of fish. Discover its outstanding universal value, superlative natural beauty, and evolutionary history as a World Heritage site.
3 days ago · Discover the best time, places and ways to visit the Great Barrier Reef, one of the world's natural wonders. Find tours, accommodation, attractions and tips to protect and enjoy this aquatic wonderland.
Jun 20, 2018 · Learn about the Great Barrier Reef, the largest coral reef system on Earth, and its diverse marine life. Find out how to get there, when to go, and how to explore this natural wonder by boat, plane, or helicopter.
Learn about the Great Barrier Reef, a unique ecosystem with thousands of species of marine life, including fish, whales, dolphins, and turtles. Find out its size, location, history, and status as a World Heritage Site and a natural wonder of the world.
