Marine heatwaves are a much bigger threat to coral reefs than previously thought, research revealing a previously unrecognized impact of climate change on coral reefs has shown. The research was done by a team of researchers from UNSW Sydney, The University of Newcastle, The University of Technology Sydney, James Cook University and The National Oceanographic and Atmospheric Administration (NOAA), USA and was published on August 8, 2019 in Journal Current Biology. In the study, scientists show for the first time what really happens to corals during marine heatwaves, and they reveal that it's not just coral animals that are affected -- their skeletons start to decay within weeks, too. This means that the 3D coral framework which provides home to many other animals on the reef is also at risk. In 2016 the team's research showed that just a 0.5OC increase in ocean temperature changes the extent of mortality that happens in coral during bleaching.

The research team recently explored that severe marine heatwaves not only trigger bleaching events but in fact can lead to heat-induced mortality of the coral animal itself. They suggested that severe heatwave-induced mortality events should therefore be considered a distinct biological phenomenon, with more direct damage different from coral bleaching. "Across the globe coral reefs are still a source of inspiration and awe of the natural world, as well as being critically important to the communities that rely upon them. Given that the degradation of coral reefs will result in the collapse of ecosystem services that sustain over half a billion people, we urgently need actions both globally and locally that protect and conserve these truly wonderful places."