The great barrier reef is experiencing a massive coral bleaching event brought on by a sustained temperature increase in the ocean surface water, with some regions of the reef 90-100 percent bleaching.
In northern Australia the seawater saw a maintained temperature about 1 degree centigrade above the normal since February. When coupled with this year’s El Nino it has resulted in extremely volatile conditions for the reef and ultimately the massive bleaching event that is underway.
On a global scale, roughly 12 percent of the world’s coral has been affected by this year’s bleaching, half of it may never recover from the damage. In 1997/98 roughly 16 percent of the world’s coral reefs experienced a similar event.
Bleaching occurs when the coral ejects Zooxanthellae Algae, which gives the coral its colour, from its skeleton due to a sustained increased in the water temperature. While this does not immediately result in the corals death, it will eventually as it relays on the Algae for most of its food.
Reefs have an economic impact of about $375 billion a year, with an estimated 500 million people worldwide who rely on them for their livelihoods.The current trend that is causing the bleaching is projected to last until early 2017 and will end up affecting the Indian Ocean, along with other regions in the Pacific.