Corals can help other corals to fight disease

Corals can help other corals to survive, according to a new study by the University of California which revealed how they fight disease.

Corals are crucial to marine ecosystems, providing shelter and breeding grounds for fish and protecting coastlines from storms and erosion, but they are increasingly at threat from pollution and the climate crisis.

But scientists may have uncovered a way to help them fight disease, as the study monitored an outbreak at a coral nursery in the Cayman Islands. They found that a mixture of corals with different genetic makeup were less vulnerable to disease than corals of the same genotype.

‘We saw that some corals were more resistant to disease just by being around other corals that were particularly resistant,’ said lead author Anya Brown, an assistant professor at the UC Davis Bodega Marine Laboratory in the Department of Evolution and Ecology. ‘Proximity to these resistant genotypes helped buffer the susceptible corals from the effects of the disease.’

Researchers say the study reveals how genetic diversity is important in reducing disease, as well as how corals are arranged in nurseries and reef restoration projects.

The ability of resistant coral to protect other corals from disease is similar to how vaccinations work, as vaccinated individuals resist disease creating a barrier blocking the virus from spreading.

Agriculture also reflects the importance for genetic diversity, as monocrops – the same crop planted in the same area each year – are more susceptible to disease than diverse systems.

‘I hope people working with coral nurseries use this as a springboard to see how this influences the spread of disease,’ Brown said. ‘Nurseries that intentionally arrange corals with mixtures of genotypes can help corals vulnerable to disease thrive. This can help build coral resilience by repopulating reefs with a diverse genetic mixture of corals.’

Photo by Francesco Ungaro