Global Warming

Corals Adapting to Global Warming

Some coral populations already have genetic variants necessary to tolerate warm ocean waters, and humans can help to spread these genes, a team of scientists from The University of Texas at Austin, the Australian Institute of Marine Science and Oregon State University have found. The discovery has implications for many reefs now threatened by global warming and shows for the first time that mixing and matching corals from different latitudes may boost reef survival.

The researchers crossed corals from naturally warmer areas of the Great Barrier Reef in Australia with corals from a cooler latitude nearly 300 miles to the south. The scientists found that coral larvae with parents from the north, where waters were about 2 degrees Celsius warmer, were up to 10 times as likely to survive heat stress, compared with those with parents from the south. Using genomic tools, the researchers identified the biological processes responsible for heat tolerance and demonstrated that heat tolerance could evolve rapidly based on existing genetic variation.

Worldwide, coral reefs have been badly damaged by rising sea surface temperatures. Bleaching—a process that can cause widespread coral death due to loss of the symbiotic algae that corals depend on for food—has been linked to warming waters. Some corals, however, have higher tolerance for elevated temperatures, though until now no one understood why some adapted differently than others.