OSU coral researcher Alex Vompe off the north shore of Mo'orea. Credit: Mackenzie Kawahara
Key points:
- Researchers studying 200 coral colonies in the French Polynesia found that some species can be resilient to marine heat waves by “remembering” how they lived through previous ones.
- The study shows ecological memory response is likely linked to the microbial communities that dwell among the corals.
- Coral reefs help regulate the sea’s carbon dioxide levels and are a crucial source for scientists searching for new medicines.
New research by Oregon State University scientists suggests some coral species can be resilient to marine heat waves by “remembering” how they lived through previous ones.
Researchers spent five years studying 200 coral colonies at a reef on the north shore of Mo’orea, French Polynesia, which had a tumultuous recent history of heat waves.
In 2010, crown-of-thorns starfish and a cyclone destroyed more than 99% of the corals, effectively hitting the reset button on the reef. Corals reestablished and went through comparatively minor heat wave events in 2016 and 2017 before experiencing the area’s most severe marine heat wave in recorded history between December 2018 and July 2019. The second-most severe heat wave soon followed, between February and July of 2020.
“We observed that some species of coral seem to remember exposure to past marine heat waves and maintain a higher level of health in subsequent heat waves,” said microbiology professor Rebecca Vega Thurber. “And Acropora retusa’s memory response was strongly linked to changes in its microbiome, supporting the idea that the microbial community has a part in this process.”
Cauliflower corals in the genus Pocillopora stayed in good health through the heat events, and their microbiomes also showed an ecological memory response. They were perturbed by the initial 2019 heat wave, but recovered to their pre-disturbance state despite the second heat wave in 2020.
“Members of coral microbial communities have unique biological features that make them more adaptable and responsive to environmental change – short generation cycles, large population sizes and diverse metabolic potential,” said Vega Thurber. “In two of the three coral species we focused on, we identified initial microbiome resilience, host and microbiome acclimatization, or developed microbiome resistance to repeated heat stress. The latter two patterns are consistent with the concept of ecological memory.”