A new study by researchers at the University of California, Davis, has found that under the right circumstances, disease-resistant corals can rescue corals that are more vulnerable to disease.
The researchers monitored a disease outbreak at a coral nursery in the Cayman Islands. They tracked the presence of disease in 650 coral fragments in various arrangements over a period of five months. They found that some corals are more resistant to disease just by being around other corals that are particularly resistant. In general, when there are only corals of the same genetic makeup, they are more vulnerable to disease than corals that grow among a mixture of genotypes. But beyond that, some vulnerable corals become more resistant to disease just by being around other corals that are particularly resistant. Proximity to the resistant genotypes helped to protect the susceptible corals from the effects of disease.
These findings provide new evidence that genetic diversity can help reduce disease transmission among corals and furthermore, it is important to consider how corals are arranged in coral nurseries or in reef restoration projects.
The ability of resistant coral to help protect vulnerable individuals appears to be similar to how vaccinations work among humans. Vaccinated individuals resist a disease, which effectively erects a barrier that weakens a disease’s ability to move through a population.
The researchers hope that the findings of this study will be integrated into coral nursery and reef restoration projects. By intentionally arranging corals with mixtures of genotypes, it will help rebuild coral resilience and help those corals that are vulnerable to disease to thrive.
Photo, posted December 30, 2014, courtesy of NOAA’s National Ocean Service via Flickr.