Neogene

Presentation

The large barrier of coral is largest coral Récif of the world. The reef is located at broad of the Queensland, in Australia. It extends on 2 600 kilometers, of Bundaberg to the point of the York Cape. Of a surface of 350.000 km ², it can be seen space. As comparison, the Germany has a surface of 357.000 km ². The Large coral barrier counts more than 2.000 islands and nearly 3.000 reefs to all kinds. One can see some close to the coasts, but most spectacular are to a few 50 km the broad one. It is registered on the Liste of the world heritage of UNESCO

The reef is regarded as the greatest alive structure on Earth. It is sometimes called the largest live animal of the world . Actually it is made up many colonies of corals. Had with its vast Biodiversity, its water clear and hot and with its great accessibility, the reef is a very popular destination for the plunger submarines. For the Australian ones, the thousands of islands, small islands and atolls composing the Large Barrier of coral constitute the 8th wonder of the world. 350 coral species of sizes, forms and different colors shelter there, in a water luminously blue, more than 1.500 fish species and shellfish.

Many cities along the coast of the Queensland offer departure daily newspapers in boat towards the reef. The town of Cairns, in the North of Queensland, is the most popular starting point to go on some of them. Several continental islands were also transformed into vacation center.

Most of the reef is protected today by the Great Barrier Reef Marine Park . It is in danger because of marine pollution, climate warming and fishing.

The first European explorer to have seen the large barrier was the British captain James Cook, at the time of his voyage from 1768. He discovered the reef by failing above on June 11th 1770.

Formation

The coral cannot live with more 30m of depth. However, one finds reefs on bases much deeper. The first alive colonies of Polype S are formed indeed near the coasts, but while the sea level goes up or that the ocean floor is inserted, of new colonies develop on the skeletons of the dead individuals.

The Large coral barrier is relatively young. The scientists think that 18000 years ago, during the glacial last era, the level of water decreased, letting emerge from the hills. The coral was then formed on the continental shelf, in front of these hills.

At the end of the glacial era, 9000 years ago, the ocean went up and submerged again the hills. The coral colonies could colonize new places, in particular at the top of the old hills. In same time, the oldest colonies followed the rise in water, the new corals developing above the dead corals.

Since, with the wire of the centuries, " murs" corals were formed, the reefs rising. On the old submerged hills appeared coral platures, fringing reefs and cayes .

Platures coral

They are formed out of not very deep water and grow horizontally rather than vertically, taking circular or elliptic forms.

Cayes

The cayes are sand islands made up of remains limestones, in particular of the shells and skeletons of polyps, that the waves reduced out of powder

Fringing reefs

They are formed close to the coasts, surrounding the islands or skirting the litoraux ones.

Environmental threats

The most significant threat for the future of the large barrier of coral and other tropical ecosystems is the Climate warming. Several of the coral species of the large barrier currently live with their limit higher of tolerance than the temperature, as shows it coral whitenings of the summers 1998 and 2002. Under the effect of water which remains too hot during too a long time, the corals expel their Zooxanthelle S persons in charge of the Photosynthèse and lose their colors, indicating their white skeletons, and die shortly after. Climate warming started the collapse of the ecosystems of reefs in the whole of the tropical zones. The increased total temperatures bring tropical storms plus violent one, but the systems of reefs are naturally resistant and recover misdeeds of the storms.

These last years, the scrubbing of the agricultural Input S (plant health manures and products), particularly those coming from the exploitations of cane with sugar, had a significant impact. The increase in silting and the bleaching of the coral destroyed broad sectors of the reef. One does not know yet which effects will have the recent quasi-collapse of the Australian industry of sugar. The starfishes Acanthaster crimson ( Acanthaster planci ) are predatory corals. When the system of the reef is not any more in balance, the starfish populations can increase dangerously. These last decades, several popular sectors of the reef were severely damaged by their attacks.

The corals suffer also beucoup from diseases.

The number of visitors of the reef is itself a problem. The popular sectors as Green Island suffered considerable damage by the tourists.

The process of blanchiement had already occurred in 1998 and 2002, where 60 to 95% of the coral populations had been touched. The situation had been restored at the end of a few weeks, but approximately 10% perished.

Since July 1st 2004, fishing is prohibited in a third of the large coral barrier. Previously, only 4% of the surface were concerned with the prohibition of fishing. The Australian ministry of the environment supports that prohibition will assign mainly the fishermen to the nets and the crab fishermen.

External bond

Plane and sights satellite:
Seen satellite of the large barrier on WikiMapia

Be-X-old: Вялікібар'ернырыф Simple: Great Barrier Reef Zh-classical: 大堡礁

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