Great Barrier Reef

Categories: Great Barrier Reef | World Heritage Sites in Australia | Geography of Australia | Marine ecoregions | Global 200 ecoregions

The Great Barrier Reef is the world's largest coral reef. The reef is located in the Coral Sea off the coast of Queensland in north-east Australia. It stretches over 2000 kilometres in length and can be seen from space. An ancient barrier reef similar to the Great Barrier Reef can be found in The Kimberlies.

The Great Barrier Reef first became known to Europeans when the explorer Captain James Cook ran aground on it in June 11, 1770. The Great Barrier Reef however was known to Indigenous Australians whose occupation of the Australian continent extends back 40,000 to 60,000 years or more. [1] [2]. The oldest parts of the reef also date from about that time.

Due to its vast biodiversity, warm clear waters and its accessibility from the floating guest facilities called 'live aboards', the Reef is a very popular destination for tourists, especially scuba divers. Many cities along the Queensland coast offer boat trips to the reef on a daily basis. Several continental islands have been turned into resorts.

The Great Barrier Reef is sometimes referred to as the single largest organism in the world. In reality it is made up of many millions of tiny organisms, as are all coral formations.

A large part of the reef is protected by the Great Barrier Reef Marine Park.

Environmental threats

The Great Barrier Reef is a large system of about 900 islands and over 3000 coral reefs, which mostly lie some distance from the mainland coastline. The coastline of north eastern Australia has no major rivers, except during tropical flood events caused by cyclones (hurricanes), several major urban centres with Cairns [3], Townsville [4], Mackay [5], Rockhampton [6] and the industrial city of Gladstone [7]. Cairns and Townsville are the largest of these coastal cities with populations of approximately 150,000 each [8]. Unlike most reef environments the Great Barrier Reef is the only one where the catchment area is home to industrialised urban areas and where extensive areas of coastal lands and rangelands have been used for agricultural and pastoral purposes.

Due to the range of human uses made of the catchment adjacent to the Great Barrier Reef some 400 of the 3000 reefs are within a risk zone where water quality has declined owing to sediment and chemical runoff from farming, and to loss of coastal wetlands which are a natural filter. Principal agricultural activity is sugar cane in the wet tropics and cattle grazing in the dry tropics regions. Both are considered significant factors affecting water quality.

The most significant threat to the future of the Great Barrier Reef in its current form and of the planet's other tropical reef ecosystems is global warming. Many of the corals of the Great Barrier Reef are currently living at the upper edge of their temperature tolerance, as demonstrated in the coral bleaching events of the summers of 1998 and 2002. Under the stress of waters that remain too warm for too long, corals expel their photosynthesizing zooxanthellae and turn colourless, revealing their white skeletons, and if the water does not cool within about a month the coral dies.

Global warming has triggered the collapse of reef ecosystems throughout the tropics. Increased global temperatures bring more violent tropical storms, but reef systems are naturally resilient and recover from storm battering. With an upward trend in temperature apparently continuing, much more coral bleaching is expected to occur in the coming decades.

Crown-of-Thorns starfish are natural predators of corals. They have a life cycle with many eggs released annually, that enables this species to boom-and-bust like locusts in a desert. The cycles are thought to be enhanced by declines in water quality such as excess nutrients from farm runoff. Since scientists and other users of the reef have been able to observe crown-of-thorns outbreaks, about 1/3 of the entire system has been affected since the 1960s. The link to an animation of Crown-of-Thorns starfish outbreaks illustrates, using data collected from the Australian Institute of Marine Science Long Term Monitoring Program, the occurrence of Crown-of-Thorns starfish outbreaks [9].

Managing the Great Barrier Reef

There are over 1.9 million visitors to the Great Barrier Reef each year [10]. Although most of these visits are highly regulated, there are some very popular areas near shore, like Green Island that have suffered damage from tourist activity.

The Great Barrier Reef was inscribed as a World Heritage Site in 1981. The Australian Government in partnership with the state of Queensland manages the Great Barrier Reef to ensure it is protected, used wisely, its range of biodiversity is understood and all people are able to enjoy and use in ther resources of the Great Barrier Reef in a sustainable manner. Through the Great Barrier Reef Marine Park Authority, the Australian Government uses a combination of zoning, plans of management,pemitting as well as education and incentives (such as eco-tourism certification) in its effort to conserve the Great Barrier Reef [11]. On July 1, 2004 the Great Barrier Reef Marine Park became the largest marine protected area in the world when the Australian Government increased the areas protected from extractive actvities such as fishing from 4.5% to 33.3%. . Also, scientists think they saw a mermaid due to an unknown species jumping out of the water with human characteristics.

Managing the Great Barrier Reef as a multiple use environment is a challenging ongoing activity that both the Australian and Queensland Governments do in close partnership with the communities and industries that use and enjoy the Great Barrier Reef.

External Links

• Official site of the Great Barrier Reef Marine Park
• Scientific research centre for the Great Barrier Reef
• Photos of the Great Barrier Reef - Terra Galleria
• Australia Underwater - All about diving in Australia - includes photo gallery from all around Australia.
• Great Barrier Reef (World Wildlife Fund)

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