The “Perfect Storm” caused the maxi coral bleaching

The “perfect storm” caused by “unprecedented climatic conditions“. This is how a group of researchers defined what caused the big bleaching of the Great Barrier Reef.

El Nino and higher temperatures have always been known to be the main causes of coral bleaching. To these two facts, now researchers added that warmer water temperatures can result in coral bleaching. Why? Well, when water is too warm, corals expel the algae living in their tissues causing the coral to turn completely white. This is called coral bleaching. When a coral bleaches, it is not dead. Corals can survive a bleaching event, but they are under more stress and are subject to mortality.

Coral bleaching on the Great Barrier Reef from GBRMPA on Vimeo.

The 2016 El Nino warmed the water near the  Gulf of Carpentaria: here water was 34°C! That’s very warm, too warm! This extremely hot water, moved towards the northern part of the Great Barrier Reef where it stopped. Warmer than usual water then stayed in this area, putting corals under a lot of stress. The majority ( 70%) of the corals died north to Port Douglas: that’s the 29% of the corals in the Great Barrier Reef.

So global warming is rapidly emerging as a universal threat to ecological integrity and function, highlighting the urgent need for a better understanding of the impact of heat exposure on the resilience of ecosystems and the people who depend on them.