The heat-tolerant algae that live symbiotically within some corals may enable their hosts to adapt to the warmer water temperatures projected to accompany long-term climate change, field studies suggest.
Many coral polyps that make up shallow reefs draw much of their nourishment from algae that live within the polyps. Those algae, all from the genus Symbiodinium, capture the energy of sunlight and pass along some stored energy to their hosts, says marine biologist Andrew C. Baker of the Wildlife Conservation Society in New York City.
Many species of the genus die off if the water temperature suddenly spikes by even a few degrees. That happened during an El Niño that began in 1997. Warmer-than-normal water temperatures bathed reefs off the Pacific coast of Panama, and many coral colonies died or temporarily lost their algal symbionts.
In 1995, 43 percent of the colonies hosted more heat-tolerant species of Symbiodinium, a grouping known as