The great Barrier Reef, Australia

The Great Barrier Reef is the only living organic collective visible from Earth's orbit. The Great Barrier Reef, off the east coast of Australia, is one of the wonders of the natural world - it is the world's largest coral reef ecosystem. It was declared a World Heritage area in 1981 and added to the National Heritage List in 2007.
The reef is scattered with beautiful islands and idyllic coral cays and covers more than 300,000 square kilometres. The Great Barrier Reef system consists of more than 3000 reefs which range in size from 1 hectare to over 10,000 hectares in area. Dunk Island is one of more than 600 islands of the Great Barrier Reef.
Human activity in the Reef areas has led to increased pollutants and the reef has suffered damage. Protecting the Reef is the responsibility of the Marine Park Authority. In 2003, the previous Australian Government and Queensland Governments, in partnership with a wide range of industry and community groups, developed the Reef Water Quality Protection Reef Plan (the Reef Plan) as a combined effort to protect the Reef.
Of particular concern is wetlands - which have decreased by over 50 per cent since European settlement. The Great Barrier Reef Coastal Wetlands Protection Program is developing measures for the long term conservation and management of priority wetlands.

The coral

Corals make up the various reefs and cays. These 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. Only live coral is coloured. Dead coral is white.
One of the greatest dangers to the habitat is the Crown of Thorns starfish. Since the 1960s the Crown of Thorns has been destroying the corals which make up the reef. Crown of Thorns outbreaks go through a series of stages which can take from 1 to 15 years. The impact of a Crown of Thorns infestation on sea and bird life can be significant as the corals die.
Another scourge of the reef is bleaching, where corals have died in large numbers. This phenomenon is not exclusive to Queensland's Great Barrier Reef, but has been observed on reefs throughout the world. It is thought the bleaching has been caused by rises in water temperature related to the El Nino effect, although the evidence is not conclusive.
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

The habitat

The World Heritage Area hosts many habitats or native environments where animals and plants naturally live.
Different degrees of protection are provided for different habitats in the World Heritage Area. One of the main aims of the Reef Plan is to maintain biodiversity within the larger ecosystem of the Reef as well as different habitats to help sustain the biodiversity of species and population levels.
The Great Barrier Reef area abounds with wildlife, including dugong and green turtles, varieties of dolphins and whales, more than 1500 species of fish, 4000 types of mollusc and more than 200 species of bird life.
However, in 2006 it was reported that over the last 40 years, 'numbers of nesting loggerhead turtles have declined by between 50 percent and 80 percent; and 'estimates of dugong populations ... indicate that they are currently only about 3 percent of what they were in the early 1960s'.
Since 2004, rezoning different areas of the reef was introduced to try and recognise important habitats as well as identify different species of fish as key targets of protection.

Tourism

More than two million people visit the reef each year generating more than $AU2 billion in tourism dollars, making tourism a major earner for the north-eastern Australian economy. Tourists are carried to the reef system by more than 500 commercial vessels, and tourism is permitted through nearly all the Park.
Most of the Reef is part of the Great Barrier Reef Marine Park and various parts of it are protected in certain ways. For example, fishing is restricted in some areas and particular animals - like whales, dolphins, green turtles and dugong - are protected.
Tourism may also have a negative impact, with fragile corals broken by reef walking, dropped anchors or by boats dropping fuel and other sorts of pollution. Even the number of people in the water with the associated run-off of sweat and suntan lotions may well have a negative impact on the fragile reef environment.
Before visiting the Great Barrier Reef Marine Park, it is important you study the zoning map for the area you are visiting to be sure of the activities that you can do and where you can do them.
The Marine Park Authority also recognises the need to protect the cultural and heritage values held by traditional owners. Since 2004, Indigenous traditional owners and government agencies are working together in relation to the traditional use of marine resources.