Status of the Great Barrier Reef

Historical State of the Great Barrier Reef

[http://www.greatbarrierreef.org/history.php]

The Great Barrier Reef was largely unknown to man until British explorer James Cook and his ship collided with Endeavour Reef near what is now modern Cooktown in June 1770. Though Cook and his crew gathered little scientific data regarding the Reef, his mishap was of great importance because it promoted awareness of the Reef on a global scale. 


While the Reef may have appeared to Cook and company to have been relatively pristine at this time, the history of the reef is one of disaster, yet the Reef has proven to be quite resilient in wake of these disasters. For centuries, the movement of tectonic plates, mass extinctions, ice ages, and fluctuations of atmospheric and ocean conditions have been responsible for the expansion and erosion of the Reef. However, today the Reef faces new anthropogenic threats that are endangering its health and chances for future recovery.


Current Threats to the Reef

Today, the reefs that make up the Great Barrier Reef are being greatly harmed by the relatively quick change in the planet's climate. As water temperature rises, coral bleaching takes place, the coral often becomes "stressed" and will expel the unicellular organisms (the zooxanthellae) which keep the coral healthy and pigmented from within their tissue. Coral bleaching has also been tied to other  sediment runoff, salinity changes, and herbicides.

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The use of herbicide, pesticide, and fertilizers eventually runs off into the Coral Sea, degrading the quality of the water therein and threatening the viability of the Reef. A massive episode of runoff off the coast of Queensland occurred due earlier this year following the mass flooding of Australia. In 1997, a severe instance of El Niño that was responsible for the rise in water temperatures by several degrees fahrenheit in some areas caused mass amounts of coral bleaching. Changes in ocean levels, both up and down also influence the well being of the Reef, as declining water exposes the coral to the ultraviolet light of the sun and rising water can drive coral deeper obstructing them from receiving their need for light. Humans are also overfishing keystone species, thereby harming the natural food chains and balance of the reef ecosystems. 

Not all threats to the Great Barrier Reef are anthropogenic, however, as some fauna are proving difficult for the Reef to handle. Namely, the crown-of-thorns starfish has been a considerable threat to reef life as they feed on coral polyps, which can decimate reefs. Their population density explodes in periods of overfishing of their predators, and this exacerbates the damage to the reefs.  

[http://media.treehugger.com/assets/images/2011/10/Crown_of_Thorns.jpg]

In 2010, the Great Barrier Reef Oil Spill, caused by a Chinese cargo ship that struck the Reef. As the ship dragged across the reef, it began spilling nearly 5 tonnes of oil into the Coral Sea, the effects of which are still being felt today.