The Great Barrier Reef, located off the coast of Queensland, Australia, is the largest coral reef system in the world. It is composed of over 3,000 reefs and stretches over 344,400 square kilometers.
The Great Barrier Reef supports many species, including many that are considered vulnerable or endangered. Apart from the many reef species, this reef system also contains 700 species of coral, 1,600 fish species, 134 shark and ray species, 30 dolphin and whale species, 6 of the 7 turtle species, 15 sea snake species, and 3,000 mollusk species. There are also thousands of plant species in the waters, and hundreds of birds that visit or nest on the island. Being the largest single structure made by living organisms, the Great Barrier Reef is so large that it can be seen from space!
The Great Barrier Reef Marine Park Authority considers the greatest threat to the Great Barrier Reef to be climate change. Increasing temperatures have caused the ocean to heat up, causing mass coral bleaching events to happen.
Coral bleaching occurs when coral polyps try to expel algae that get inside their tissues. They normally have a good relationship with the algae, with the algae providing them with up to 90% of their energy. With the ocean temperature increasing, algae populations increase. The corals overcompensate their expulsion of the algae and become more susceptible to disease and lose their main energy source.
Mass coral bleaching events happened in the summers of 1998, 2002, and 2006. It is expected that these events become an annual occurrence.