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Stressful Times

May 8, 2017

When water temperatures get too warm, corals expel their algal symbionts, a process known as coral bleaching. Without symbionts to provide food, corals can starve and die. This computerized tomography (CT) scan of a sample of living coral reveals a bright white stress band across the top of the core. WHOI scientist Anne Cohen and her students have studied these unusual skeletal features and linked them to bleaching-induced starvation. This coral bleached but did not die during the 2009-2010 El Niño, which raised water temperatures on Palau by 1 degree Celsius—enough to cause bleaching across the entire Palau archipelago. (Photo courtesy of the Cohen Laboratory, Woods Hole Oceanographic Institution)