During marine heat waves, viruses may increase their attacks on the symbiotic algae that give reef-building corals their amazing colors, research finds.

Few studies have examined how heat and other forms of stress affect coral virus outbreaks, and fewer still have looked at the reef-scale dynamics of those outbreaks. The study in ISME Communications does both. It’s also the first to analyze the reefwide prevalence, persistence, triggers, and health impacts of dinoflagellate-infecting RNA viruses (dinoRNAVs), single-stranded RNA viruses that infect the symbiotic algae that live inside the corals.

Lead author Lauren Howe-Kerr says coral and marine disease researchers are paying closer attention to coral viruses in the wake of studies in October 2021 and February 2022 that found evidence suggesting viral infections of symbiotic dinoflagellates might be responsible for stony coral tissue loss disease (SCTLD). One of the deadliest coral diseases ever recorded, SCTLD has been decimating reefs in Florida and the Caribbean since it was first identified in 2014.

“While this study is not focused on SCLTD, it builds our understanding of coral viruses, and particularly RNA viruses that infect coral endosymbionts,” says Howe-Kerr, a postdoctoral researcher at Rice University.

“Our work provides the first empirical evidence that exposure to high temperatures on the reef triggers dinoRNAV infections within coral colonies, and we showed those infections are intensified in unhealthy coral colonies,” Howe-Kerr says.

Read the full article about heat waves and corals by Jade Boyd at Futurity.