Saturday, September 30, 2006

The Great Barrier Reef

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.

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. Some people believe that the most significant threat to the future of the Great Barrier Reef in its current form 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 and 2002. 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 unfortunately 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, others point to data that demonstrates that the global temperature has never changed by more than a degree for a very long time.