The Great Barrier Reef is the world’s largest coral reef system, stretching for about 2,300 kilometres along Australia’s northeastern coast.
It lies in the Coral Sea off Queensland and includes thousands of individual reefs and hundreds of islands. The system is built by billions of tiny coral polyps, whose hard limestone skeletons accumulate over long periods. Despite its name, the Great Barrier Reef is not one continuous reef.
The reef supports exceptional biodiversity, including corals, fish, sea turtles, seabirds, molluscs, and marine mammals. It is also culturally important to Aboriginal and Torres Strait Islander peoples, whose connections with the sea and reef extend over many thousands of years.
Coral bleaching occurs when unusually warm water causes corals to expel the algae living in their tissues. Bleached coral is stressed but is not automatically dead. The Great Barrier Reef Marine Park was established in 1975, and the reef was added to the UNESCO World Heritage List in 1981.