The world is experiencing its third mass coral bleaching event. Due to elevated temperatures at tropical locations over the whole planet, large populations of corals are starting to turn white. This is bad, as bleaching can lead to large-scale decreases in coral health and ultimately their death. Coral reefs provide shorelines with protection from storms, are foundational to tropical tourism and provide critical habitat to thousands of species. Large-scale coral death following mass bleaching leads to reef erosion, loss of shoreline protection, loss of tourism income and the livelihoods that depend on them, and loss of critical habitat.
Following the last mass bleaching event in 1997–98, 16 percent of the world’s corals died. This current mass bleaching is projected to be just as disastrous as the last. On top of that, this year’s event follows on the heels of bleaching that occurred in some parts of the world last year. In Hawaii, for example, researchers documented coral bleaching in both 2014 and 2015, potentially setting up these reefs for severe declines now.
While many corals die following bleaching events, there are always survivors. Over the past decade, I’ve focused on trying to figure out why some corals make it. By identifying why some corals survive, we gain a deeper understanding of their biology and can better predict coral diversity and persistence. Ultimately we can make better coral reef management decisions.
Why Corals Bleach
Corals are symbiotic organisms. They’re animals made up of polyps that harbor millions of microscopic plant cells (called algae) within their tissues, which gives corals their color.
