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Great Barrier Reef

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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.

Satellite image of a part of the Great Barrier Reef. Photo courtesy of NASA.

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. 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.

Age

The Great Barrier Reef first became known to Europeans when the explorer Captain James Cook ran aground there, on June 11, 1770. The Great Barrier Reef however was known to Indigenous Australians whose occupation of the Australian continent is thought to extend back 40,000 to 60,000 years or more. [1]

According to the 2005 fact sheet published by the Marine Park Authority of the Australian Government [2], the current reef structure is believed to have begun growing on an older platform about 18,000 years ago, but the oldest datable coral on the reef now is a species of Porites known as boulder coral, which is only about 1,000 years old (it grows at about 1 centimetre/year).

The research outcomes funded by the CRC Reef Research Centre [3] estimates the present reef structure at 6,000 to 8,000 years old, formed upon coral dating back half a billion years. Reefs fluctuate (grow and recede) as the sea level changes. An ancient barrier reef similar to the Great Barrier Reef can be found in The Kimberleys.

History

The reef has, over the years, brought many ships to grief. James Cook's HM Bark Endeavour hit the reef in 1770 and sustained considerable damage. It was finally saved after lightening the ship as much as possible and re-floating it during an incoming tide. One of the most famous wrecks is that of the HMS Pandora, which sank on August 29, 1791 killing 35. The Queensland Museum has been leading archaeological digs to the Pandora since 1983. [4]

Environmental threats

Runoff and coastal development

[wetland]]s which are a natural filter. Principal agricultural activity is sugar cane farming in the wet tropics and cattle grazing in the dry tropics regions. Both are considered significant factors affecting water quality. [5]

Global warming and coral bleaching

hey brandon

 
Bioerosion (coral damage) such as this may be caused by coral bleaching. [1]

Some people believe that the most significant threat to the status of the Great Barrier Reef 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, 2002 and most recently 2006. [6] As was seen at those times, under the stress of waters that remain too warm for too long, corals expel their photosynthesising zooxanthellae and turn colourless, revealing their white calcium carbonate skeletons, and if the water does not cool within about a month the coral will die. Australia has just experienced its warmest year on record and abnormally high sea temperatures during summer (2006) have caused massive coral bleaching in the Keppel Island group.

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. While some believe that an upward trend in temperature will cause much more coral bleaching [7], others point to data that suggests that the global temperature has never changed by more than a degree for a very long time.

 
Crown-of-Thorns starfish

Crown-of-Thorns starfish

Crown-of-Thorns starfish are thought to be natural predators of corals. The exact origin of this species is unknown, and it is only speculated that they are native to Australia. 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 one third 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 [8]. In addition, the Giant Triton, a natural predator of the Crown-of-Thorns starfish, is often overfished as its shell is prized by collectors.

Fishing

The fishing industry in the GBR is worth $104 million (Australian dollars) annually [9]. It employs approximately 2000 people, and fishing in the Reef is pursued commercially, for recreation, and as a traditional means for feeding one's family.

Effects of Fishing

Disruption to food chains is caused by unsustainable overfishing of key species. The Queensland government announced a Fisheries (Coral Reef Fin Fish Fishery) Management Plan 2003 aimed at reducing the annual commercial catch to 1996 levels, disallowing fishing when the fish are spawning and increasing the minimum legal size of fish. [10]

Up until mid-2004, only 4.6% of the Great Barrier Reef World Heritage area was protected from fishing. (It is now one third.) [11] The main impacts from fishing are

  • Overfishing of key species (eg. Giant Triton)
  • Pollution from boats
  • Bycatch (species that they’re not looking for, e.g. crabs, dolphins, turtles, dugongs)
  • Reef damage (anchors, nets)
  • Habitat destruction from trawling [12]

Shipping and oil

Shipping accidents are a real concern, as several commercial shipping routes pass through the Great Barrier Reef. From 1985-2000, there were 11 collisions and 20 groundings on the inner Great Barrier Reef shipping route. The leading cause of shipping accidents in the Great Barrier Reef is human error. [13]Ships also have been known to discharge waste and foreign species in their ballast water and the antifouling paint on the hulls is toxic.

Also, it is suspected that the Reef is the cap to an oil trap, as it is calcium carbonate. Before it was World Heritage listed, there was some speculation about drilling for oil and gas there. Although there is no oil drilling on the reef, oil spills are still a frequent occurrence there.

Managing the Great Barrier Reef

 

There are approximately two million visitors to the Great Barrier Reef each year.[14] Although most of these visits are managed in partnership with the marine tourism industry, there are some very popular areas near shore (such as Green Island) that have suffered damage due to overfishing and land based run off. Any impacts from tourist activity merely exacerbate the more pronounced effects of land based run-off and overfishing.

The Government of Australia manages the reef through the Great Barrier Reef Marine Park Authority and in partnership with the Government of Queensland, to ensure that it is widely understood and used in a sustainable manner. A combination of zoning, management plans, permits, education and incentives (such as eco-tourism certification) are used in the effort to conserve the Great Barrier Reef.

The Great Barrier Reef was selected as a World Heritage Site in 1981. On July 1, 2004 the Great Barrier Reef Marine Park became the largest protected sea area in the world when the Australian Government increased the areas protected from extractive activities (such as fishing) from 4.6% to 33.3% of the park. [15]

References

  1. ^ ReefED (unknown date). reefED - GBR Traditional Owners [online]. Available: http://www.reefed.edu.au/explorer/traditional_owners/index.html [Access date: 28 May 2006]
  2. ^ Great Barrier Reef Marine Park Authority (2005). Reef Facts 01 [online PDF]. Available: http://www.gbrmpa.gov.au/corp_site/info_services/publications/newsletters/reef_facts/reeffacts-01.pdf [Access date: 28 May 2006]
  3. ^ CRC Reef Research Centre Ltd (unknown date). What is the Great Barrier Reef? [online]. Available: http://www.reef.crc.org.au/discover/coralreefs/coralgbr.html [Access date: 28 May 2006]
  4. ^ Queensland Museum(unknown date). Queensland Museum - HMS Pandora [online]. Available: http://www.qmuseum.qld.gov.au/features/pandora/index.asp [Access date: 28 May 2006]
  5. ^ Australian Government Productivity Commission(2003). Industries, Land Use and Water Quality in the Great Barrier Reef Catchment - Key Points [online]. Available: http://www.pc.gov.au/study/gbr/finalreport/keypoints.html [Access date: 29 May 2006]
  6. ^ Great Barrier Reef Marine Park Authority (unknown date). Coral Bleaching and Mass Bleaching Events [online]. Available: http://www.gbrmpa.gov.au/corp_site/info_services/science/climate_change/coral_bleaching.html[Access date: 30 May 2006]
  7. ^ Greg Roberts (Sydney Morning Herald) (2003). Great barrier grief as warm-water bleaching lingers [online]. Available: http://www.smh.com.au/articles/2003/01/19/1042911270265.html[Access date: 30 May 2006]
  8. ^ Australian Institute of Marine Science (unknown date). AIMS Research - Reef Monitoring [online]. Available: http://www.aims.gov.au/monmap/cotsanimation/cots.htm [Access date: 28 May 2006]
  9. ^ Access Economics Pty Ltd (2005). Measuring the economic and financial value of the Great Barrier Reef Marine Park [online PDF]. Available: http://www.gbrmpa.gov.au/economic_values_report.pdf [Access date: 28 May 2006]
  10. ^ The State of Queensland (Department of Primary Industries and Fisheries) (unknown date). Coral Reef Fin Fish Fishery Management Plan - A summary [online]. Available: http://www2.dpi.qld.gov.au/fishweb/11379.html [Access date: 28 May 2006]
  11. ^ Great Barrier Reef Marine Park Authority (unknown date). Marine Park Zoning [online]. Available: http://www.gbrmpa.gov.au/corp_site/management/zoning/index.html [Access date: 28 May 2006]
  12. ^ CSIRO Marine Research (1998). Environmental Effects of Prawn Trawling [online]. Available: http://www.marine.csiro.au/LeafletsFolder/26trawl/26.html [Access date: 28 May 2006]
  13. ^ Australian Maritime Safety Authority (2002). Great Barrier Reef Review Report - Review of ship safety and pollution prevention measures in the Great Barrier Reef [online]. Available: http://www.amsa.gov.au/Shipping_Safety/Great_Barrier_Reef_and_Torres_Strait/GBR_Review_Report/Shipping_in_the_GBR.asp [Access date: 30 May 2006]
  14. ^ Great Barrier Reef Marine Park Authority (unknown date). Number of Tourists Visiting The Great Barrier Reef Marine Park [online]. Available: http://www.gbrmpa.gov.au/corp_site/key_issues/tourism/gbr_visitation/page_02.html [Access date: 28 May 2006]
  15. ^ Environment News Service - International Daily Newswire (2004). Fish Boats Barred From One-Third of Great Barrier Reef [online]. Available: http://www.ens-newswire.com/ens/jul2004/2004-07-01-06.asp [Access date: 28 May 2006]
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