Coral reefs cover less than one percent of the Earth's surface but are some of the most diverse and important habitats on Earth. They are living animals and not plants as sometimes assumed and form part of a complex marine ecosystem.
Reefs are made up of many millions of tiny organisms, known as coral polyps. A unique partnership between the coral which is an animal and microscopic plant cells called zooxanthellae that give the reef it colours. The plants feed off the animal waste and in turn create food for the coral through photosynthesis. Both animal and plant are mutually dependent on each other for survival, a relationship known as symbiosis.
An estimated 10 percent of the world's coral reefs have already been destroyed, and another 60 percent are dying. At the present rate of change they may be completely gone by 2050.
No single factor has caused the reefs to deteriorate in size and health. Coral reefs around the world are being killed and degraded by a combination of:
Coral reefs exist in many tropical and sub-tropical oceans and seas. Some of these include: The Red Sea coast of Saudi Arabia, Yemen and Egypt; The Persian Gulf and Gulf of Oman coast of Bahrain, Oman, Iran, Saudi Arabia and United Arab Emirates; The Arabian Seas coast of Pakistan and India; Caribbean Sea coast of Central American countries and around the islands of the West Indies; Western Pacific around the Hawaiian islands and the island nations of the Fiji, Federated States of Micronesia, French Polynesia, Johnston Atoll, Palau, Papua New Guinea, Western Samoa; Eastern Pacific Ocean coasts of Colombia, Mexico, Panama and the Galapagos islands; Atlantic Ocean coast of Florida, Bermuda, Brazil; Bay of Bengal coast of India and Sri Lanka; Indian ocean coast of Somalia, Kenya Tanzania, Maldives, Mauritius Seychelles, Madagascar Indonesia and Western Australia; Andaman Sea coast of Burma and the Andaman islands; South and East China Sea coast of China, Vietnam, Japan, Taiwan and the Philippines; Gulf of Thailand coast of Cambodia Thailand, Malaysia; and the Java and Timor Sea Reefs.
The Great Barrier Reef of Australia is by far the largest of the world's coral reefs. It extends from New Guinea down the coast of Queensland to a point about level with the town of Rockhampton, a total distance of 1250 nautical miles. But unlike its name suggests it is not a continuous, single reef but a collection of many small islands and coral reefs. It is made up of three distinct regions: the Northern, Central and Southern. The Northern region it is less than three metres deep, uniformly dispersed and forms a continuous line along the edge of the continental shelf. In the Central region the reef is between 30 and 60 metres deep and there are few shelf edge reefs. In the Southern region depths exceed 60 metres, the reefs are well distributed and it possesses very strong shelf edge reefs.
Contained within the inner part of the continental shelf are the inner reefs. Some are fully formed horseshoe-shaped coral reefs while others are in various stages of resorption. Mangroves partially cover some of the reefs and some are even capped with small islands or cays that are made of fine sand from the erosion of the coral by wave action. Over time, some of the islands become covered with vegetation. The outer reefs contain the most actively growing corals. They are characterised by an almost continuous line of breakers along the edge of the continental shelf. It is these reefs that prompted Matthew Flinders to name the area the 'Great Barrier Reef'.
Coastal areas adjacent to the Great Barrier Reef have been modified since European settlement by deforestation, urbanisation, agriculture, particularly sugar cane cultivation and beef grazing. Sediment and nutrient flow from rivers into coastal areas are four times higher than at the time of the first European settlement.
As a result of the new zoning plan implemented by the Australian Government in July 2004 there has been an increase of “green” or highly protected areas within the Great Barrier Reef from 4.6% to 33.3%. The amount of general use zones available for commercial and recreational fishing, as well as tourism has also been decreased from 78% to 33.8 % significantly reducing the pressure placed on certain areas within the Great Barrier Reef Marine Park. While pressures from fishing, industry and tourism have diminished, the greatest threat to reef is now global warming.
Coral reefs are beautiful natural wonders of the world, an underwater diversity of shapes and colours. Solely, from an aesthetic perspective, coral reefs should be protected.
But it has been calculated that coral reefs worldwide generate hundreds of billion of dollars a year from tourism recreational fishing and commercial fishing. They are important for the economic stability of many local communities and support millions of jobs. A broad range of stakeholders are dependent on the survival of coral reefs.
In the United States alone, over US$100 million is made each year from commercial fishing and a further US$100 million from recreational fishing from coral reefs. A report by the director of Sydney University's Coral Reef Research Institute, Ove Hoegh-Guldberg, stated that AU$1.5 billion was generated annually by tourism at the Great Barrier Reef. In developing countries about a quarter of the total fish catch comes from coral reefs.
Furthermore coral reefs are repositories of biochemicals, which may be developed into new materials or pharmaceuticals and possible cures for cancer, arthritis, and other diseases.
They act as spawning ground for fish and support a large range of other species. Coral reefs play a key role in maintaining ecological integrity.
What you can do
Don’t visit ecologically sensitive coral reefs. Support tourist activities and solutions which help conserve coral reefs.
If you own or rent a boat ensure that it does not damage the coral. Anchor the boat well away from the reef.
Report anyone who actively damages areas of coral to the appropriate authorities.
Do not purchase jewellery or other products made from coral.
Write a letter or email to the editor of your local newspaper; urge him or her to publish your concerns about destruction of your countries coral reefs.
Write a letter or email to the politicians listed under the heading for your country on our automated lobbying service on the Information for Action website and ask for more to be done to protect our coral reefs. If you live in a country that does not have any coral, write to the Queensland government in Australia and ask them to do more to protect the Great Barrier Reef.
Ring talk back radio expressing concern that your coral reefs are no longer protected by your governments.