When corals are stressed by changes in their surrounding environment, such as an excessively warming ocean, they expel the symbiotic algae living in their tissues that give them their colour. This causes them to turn completely white. The white is in fact their skeletons revealed through their now-translucent flesh. This phenomenon is called coral bleaching. When corals bleach, they lose their ability to produce food and quite rapidly they starve to death. The Great Barrier Reef (GBR) experienced unprecedented back-to-back bleaching in 2016 and 2017 resulting in mortality across vast areas of the Reef. This haunting expanse of bleached corals was captured on Lizard Island in the far northern section of the GBR in 2016.