‘Graveyard of corals’ found after extreme heat and cyclones hit northern Great Barrier Reef

Marine scientists say there have been ‘substantial losses’ of coral cover after extreme weather at the northern Great Great Barrier Reef. Photograph: Australian Institute of Marine Science

Reefs across the north of the Great Barrier Reef have seen “substantial losses” of coral cover after a summer of extreme heat, two cyclones and major flooding, according to the first results of surveys from government marine scientists.

After the most widespread coral bleaching event seen on the world’s biggest reef system, the Australian Institute of Marine Science said one area around Cooktown and Lizard Island had lost more than a third of its live hard coral – the biggest annual drop in 39 years of monitoring.