Major Global Coral Reef Bleaching Events Predicted For 2015

coral-bleaching-american-samoaWarm ocean temperatures in the tropical Indian and Pacific Oceans could be bringing major coral bleaching events to reefs around the world in 2015, according to the National Oceanic & Atmospheric Administration’s (NOAA) latest forecast. Coming fresh on the heels of 2014’s severe coral bleaching events, this prediction doesn’t bode well for one of the most important, and imperiled, ecosystems on the planet.

We’ve covered coral bleaching quite extensively here on Planetsave, but if you missed any of our previous articles, it’s important to know that not only are coral reefs similar to rainforests in the amount of diversity they support, and that they serve as home to about 25% of marine life, though they only take up a relatively small amount of space in the ocean.

It’s currently estimated that 20% of the Earth’s coral reefs are “damaged beyond recovery” and that half of the surviving coral reefs “are under risk of collapse,” so the news that the potential for more major coral bleaching events this year is a sobering thought.

“The outlook shows a pattern over the next four months that is similar to what we saw during global coral bleaching events in 1998 and 2010. We’re really concerned that 2015 may bring the third global coral bleaching event.” – Mark Eakin, NOAA Coral Reef Watch Coordinator

According to the most recent outlook on coral reefs from the NOAA’s Coral Reef Watch, the greatest coral bleaching threat (through May 2015) is expected to be in the Indian and western South Pacific oceans, and that scientists in American Samoa are already seeing the start of coral bleaching in their shallow reefs:

“In the Pacific, thermal stress has already reached levels that cause bleaching in the nations of Nauru, Kiribati, and the Solomon Islands, and is expected to spread to Tuvalu, Samoa, and American Samoa in the next few months. In the Indian Ocean, thermal stress may reach levels that cause bleaching around Madagascar, Mauritius, Seychelles, and parts of Indonesia and western Australia.”

Coral bleaching, which happens because of stress to the corals from variations in temperatures, nutrients, or light, causes the corals to expel the algae which live within their tissues, after which the corals become pale or white. The symbiotic algae (zooxanthellae) are a major source of food for the corals, and while corals may survive a bleaching event, they are at risk for increased mortality due to their weakened state, and if the algae loss continues for a prolonged period, the corals will die.

coral bleachingAlong with the dire warning of the potential for major global coral bleaching events, the Coral Reef Watch had some good news as well, in that their satellite observational capacity, which serves “near real-time” data on coral reefs, can now focus on areas of reefs as small as 5 square kilometers, boosting the amount of data handled by the program by up to 50 times. This additional resolution is said to be able to help scientists and managers of coral reefs “accurately pinpoint bleaching thermal stress levels at coral reef scales” so as to be able to take appropriate actions for reef protection.

Source: NOAA | Images: NOAA

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