The microbiomes of corals — which comprise bacteria, fungi and viruses — play an important role in the ability of corals to tolerate rising ocean temperatures, according to new research led by Penn State. The team also identified several genes within certain corals and the symbiotic photosynthetic algae that live inside their tissues that may play a role in their response to heat stress. The findings could inform current coral reef conservation efforts, for example, by highlighting the potential benefits of amending coral reefs with microbes found to bolster corals’ heat-stress responses.
“Prolonged exposure to heat can cause ‘bleaching’ in which photosymbionts (symbiotic algae) are jettisoned from the coral animal, causing the animal to die,” said Monica Medina, professor of biology, Penn State. “We found that when some corals become heat stressed, their microbiomes can protect them from bleaching. In addition, we can now pinpoint specific genes in coral animals and their photosymbionts that may be involved in this thermal stress response.”
Viridiana Avila-Magaña, former student at Penn State and currently a postdoctoral fellow at Colorado University Boulder, noted, “Previous studies on the molecular mechanisms underlying corals’ heat-stress tolerance have tended to focus on just the animal or the photosymbiont, but we now know that the entire holobiont — the coral animal, photosymbiont and microbiome — is involved in the stress response.”
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The study site in Puerto Morelos, Mexico (Caribbean Sea), where the researchers collected Siderastrea radians, the shallow water starlet coral. (Photo Credit:: SERGIO GUENDULAIN-GARCÍA)