In the study, researchers reviewed some of the ground­breaking and recent coral-bleaching discoveries from an ecological, molecular and physiological viewpoint.

Third option

According to the researchers, some studies claim that global climate change mitigation is the only way to save coral reefs, while others claim that efficient local management can also help coral reefs survive. As a third option for coral reef conservation, the study's authors proposed mesoscale sanctuaries. They stated that there are currently several mesoscale sanctuaries, such as the Micronesia Challenge, although they are uncommon across national borders.

“Global warming is the No. 1 threat to coral reefs right now,“ said Andrea Grottoli, co-author of the study and a professor in earth sciences at Ohio State University. “So, when we think about coral reef conservation, we cannot limit ourselves to arbitrary geographic boundaries.”

Designing large-scale protected areas

To safeguard corals from local and regional disturbances caused by climate change, multinational networks of protected areas could be created and enforced, said the researchers. Localities, where reef corals can persist and potentially expand in the future, should be included in such mesoscale sanctuaries, they added.

Climate proofing reefs

Reefs must be “climate-proofed,” according to the study, by preserving both coral-reef ecosys­tems and genetic variety, which can be used as a source of positive selection.

Although traditional marine reserves are intended to protect local biodiversity and prevent overfishing, the study's authors said that additional mesoscale sanctuaries may be required to preserve both the genetic diversity needed to fuel the evolutionary adaptation of corals (and the many other species living in or around them), and large enough populations to serve as a source of migrants across environmental changes.

In the study, which was published in the journal Global Change Biology and funded by the National Science Foundation, the researchers recommended international meso­scale sanctuaries (i.e., mesoscale networks that span national borders) to safeguard various habitats and genetic variety, which will provide coral populations the best chance of surviving climate change. The scientists added that it is critical to understand which coral species and reefs should be protected first, based on their adaptive potential and natural resilience.

In the study, researchers also assessed which data and processes can help prediction models improve, and offered a conceptual framework that unifies observations across biological scales.