Race to Adaptation

Many online sites warn of coral reefs completely dying off within a generation and support that prediction with the fact that a large number of corals have either already died off or are facing severe bleaching.

“Coral bleaching is occurring in tropical areas, mostly because corals prefer a very specific temperature range which favors lower latitudes. Unfortunately, coral bleaching is affecting almost all corals around the world, including the Great Barrier Reef in Australia, the Mesoamerican reef and the Caribbean, and the Coral Triangle in Southeast Asia,” Rowan said.

Corals face a variety of stressors that lead to bleaching. Scientists ultimately separate these stressors into two types: local and global stressors.

“So pollution, overfishing, and destruction or sedimentation from coastal development are all local stressors. When it comes to global stressors, we’re talking about climate change, which drives both coral bleaching and ocean acidification, and diseases, like the Stony Coral Tissue Loss Disease,” Sturm said.

However, new findings give scientists hope that some corals will survive if they are given time to adapt and adjust to new ocean conditions.

“The projections that we’re going to lose all our coral reefs were exaggerated. We now know that some corals have the ability to acclimate and adapt to a warming, acidifying ocean. The key thing to keep in mind is that there will be winners and losers as the oceans warm and acidify, but we will probably not lose coral reefs entirely,” Hixon said.

Scientists have discovered that not all corals respond the same way to changes in climate. Researchers compared staghorn coral with mountainous star coral in a study led by the University of Miami (UM) Rosenstiel School of Marine and Atmospheric Science. They discovered that staghorn coral was more sensitive to heat stress than mountainous star coral.

Given time, some reefs will be able to adjust to the warming ocean temperatures and rising acidity levels.

“Our scientific research tells us that coral reefs can adapt to the effects of climate change. If we keep corals healthy in strategic, ecologically connected networks around the world, we can create the conditions under which evolution can help rescue reefs,” Rowan said.