A new study has found that the Great Barrier Reef corals will lose its tolerance from bleaching events. The study says that the Great Barrier Reef corals were able to survive past bleaching events because they were exposed to a pattern of waters getting gradually warmer, before a big bleaching event. But due to recent climate change this pattern is likely not to occur anymore because of the drastic changes in temperature.
In a paper published in Science today, researchers from ARC centre of Excellence for Coral Reef Studies as well as the U.S. National Oceanic and Atmospheric Administration investigated what this warming pattern means for Great Barrier Reef coral bleaching events that are to occur in the future. It is explained that when a bleaching event occurs it is like a marathon for corals, and that when corals are predisposed to a pre-stress period before bleaching they have a lot easier time tolerating the warmer waters and are able to survive the heat shocks.
These types of “pre-stress” conditions are expected to disappear when the seawater temperatures rise by as little as half a degree, which has been predicted to occur soon. So because they will not have these “pre-stress” conditions they will be directly exposed to heat shock events. According to NOAA future summers will bring more bleaching events and they will be more severe and the coral will be at greater risk for dying.
The way they can predict this is through 27 years worth of data that looked at sea surface temperatures, past bleaching events, and studied how corals responded to warming conditions. Other predictions are that different reefs on the Great Barrier Reef will lose their protective mechanism (pre-stress/practice run) at different rates. It is also predicted that if they lose their protection they will bleach faster as well as stay in this state longer.
According to Bill Leggat, he says that knowing what temperature patterns are present in different reefs these allows them to know the impact and capacity bleaching events will have as well as survival. Knowing these different aspects of bleaching and survival can help increase the likelihood of coral survival through these events by helping reduce stressors, like pollution. There results show the importance of global action against green house gasses and reduce emissions.