The Great Barrier Reef is the world's largest coral reef. The reef is located off the coast of Queensland in northeast Australia. It stretches 1260 miles in length and can be seen from space.
Due to its vast biodiversity, warm clear waters and its accessibilty from the floating guest facilities called 'live aboards', the GBR is a very popular destination for 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.
A large part of the reef is protected by the Great Barrier Reef Marine Park.
One of the severest threats to the future 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 and 2002. Under the stress of waters that remain too warm for too long, corals expel their photosynthesizing zooanthellae, turn colorless, revealing their white skeletons, and soon die. 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. Crown-of-thorns sea stars are predators of corals. When the reef system is out of balance, their populations can explode and they become enemies of the reef.
In recent years, run-off from agriculture, especially sugarcane fields, has had a massive impact on the reef. Increased silting and coral bleaching has killed large areas of the reef.