Australias Great Barrier Reef is experiencing one of the most extensive and serious coral bleaching events in recorded history after a summer of extreme temperatures and oceanic heat effectively cooked the delicate corals that make up the iconic structure.

The Australian Institute of Marine Science recently completed an intensive, large-scale survey of the reef, which is a system of about 3,000 individual reefs that stretches nearly 1,500 miles along the coastline. For the first time, extreme levels of bleaching have been seen along all regions of the Great Barrier and around 75% of the reefs surveyed showed signs of prevalent bleaching.

Aerial photos released Wednesday show the widespread devastation underway after some areas of the reef were hit by record levels of heat .