Beyond the Pale

We’re in the midst of the third global coral-bleaching event.

October 09, 2015

Photo: XL Catlin Seaview SurveyA before and after image of the bleaching in American Samoa. The first image was taken in December 2014. The second image was taken in February 2015.

The first coral-bleaching event to whiten reefs worldwide happened in 1998, an El Niño year. Some 16 percent of the planet’s reefs died. In 2010, El Niño brought another. Now NOAA says we’re in the midst of the third ever such event that has dire implications for biodiversity, fisheries, and the overall health of our oceans.

This time, the XL Catlin Seaview Survey was ready. The team started taking panoramic photographs of reefs in 2012 to create a visual record of the change over time. Acting on NOAA’s dire predictions for this year, they captured images of the event unfolding.

Ocean warming from climate change, exacerbated by El Niño’s unusually high temperatures, makes the marine invertebrates eject the symbiotic algae living in their tissues, which they depend on for nutrition (and their vibrant color). Corals don’t always after die after bleaching, but the current whiteout started in 2014, and a continuing El Niño could drag the phenomenon out to 2016. That degree of prolonged stress has scientists seriously worried.

Corals just didn’t evolve to live in a hot tub. 

Photo: XL Catlin Seaview SurveyThis coral was photographed in American Samoa. You can clearly see the white skeleton of the coral which exposed when the tissue of the animal loses its color and becomes transparent.

Photo: XL Catlin Seaview SurveyA scientist records a bleached fire coral in Bermuda.

Photo: XL Catlin Seaview SurveyA fire coral in Bermuda. The one on the left is a healthy fire coral, while the one on the right is completely bleached.

Photo: XL Catlin Seaview SurveyA green turtle photographed in Hawaii on a bleached reef in late 2014.

onEarth provides reporting and analysis about environmental science, policy, and culture. All opinions expressed are those of the authors and do not necessarily reflect the policies or positions of NRDC. Learn more or follow us on Facebook and Twitter.

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