Conditioning Corals to Survive Stress

Since the 1980s, coral reefs have been declining globally due to a combination of stressors, including increasing water temperatures and nutrient pollution. In addition to reducing sources of stress through local and global management actions, coral restoration has recently gained popularity as a conservation strategy. While coral restoration has shown promising results, the survival of planted corals often declines after the first few years, likely due to the same sources of stress that threaten wild populations. Coral restoration must therefore be combined with increases in coral stress tolerance to ensure long-term success.

A new hope for coral conservation may be found through the role of epigenetic mechanisms - heritable modifications to gene function that are responsive to environmental conditions. Studies have shown that exposure to environmental stressors can leave an "environmental memory" in corals, preconditioning corals and increasing coral stress tolerance. Epigenetic modifications can promote rapid acclimatization and likely play a major role in preconditioning and environmental memory. Epigenetic research can therefore be applied to coral restoration in hopes of conveying stress tolerance and increasing the long-term survival of restored corals.

Serena Hackerott, a doctoral student with the NSF CREST Center for Aquatic Chemistry and Environment, is applying epigenetic research to coral restoration efforts. In collaboration with Reef Renewal Bonaire, Hackerott's team is monitoring two endangered coral species: Acropora cervicornis and A. palmata, or staghorn and elkhorn corals, at coral nursery sites in Bonaire, Caribbean Netherlands. Environmental conditions, especially water temperature and nutrient concentrations, are predicted to vary seasonally and across coral nursery sites with different proximities to sources of coastal runoff. Results from this research have the potential to greatly increase the long-term success of coral restoration efforts by identifying factors that best prepare corals to tolerate exposure to stressful conditions.

The NSF CREST Center for Aquatic Chemistry and Environment is housed within the Institute of Environment, a Preeminent Program at Florida International University.