Certain coral species are able to survive warming waters due to climate change because they are able to "remember" how they lived through previous heat waves, according to scientists at Oregon State University.
The study’s findings contained evidence that the memory response is likely connected to tiny microbial communities that live among the corals, and understanding how that works is important for future conservation goals.
Rapid adaptation and memory response
The increase in frequency of heat waves on Earth due to climate change is likely, according to Alex Vompe, the study’s lead author.
So understanding how some corals are able to adapt and survive while others cannot is important because they are vital to how the Earth’s oceans function.
Vompe and his team spent five years studying 200 coral colonies on the north shore of Mo’orea, French Polynesia.
They were able to observe data from 2010 when crown-of-thorns starfish and a cyclone destroyed more than 99% of the corals.
OSU coral researcher Alex Vompe off the north shore of Mo'orea. (Mackenzie Kawahara)
The corals were also hit by several minor and severe heat waves between 2016 and 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 Rebecca Vega Thurber, a doctoral student who works in the lab of microbiology.
Other corals that showed evidence of a memory response to recent heat waves were the cauliflower corals. These corals were initially disturbed due to a heat wave in 2019 but were able to sustain good health through a 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," Vega Thurber said. "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."
OSU coral researcher Alex Vompe working in a biosafety cabinet (Olivia Harmon)
The importance of healthy coral reefs
Coral reefs are found in less than 1% of the world’s oceans but are home to nearly a quarter of all known marine species, according to the study.
They also help regulate the carbon dioxide levels in the ocean and provide crucial intel for scientific research of medicines.
The continued threats of climate change could stress the relationship between coral reefs and the microbial communities that help keep them alive, which can have major consequences for the health of Earth’s oceans.
Not only do coral reefs protect coastlines from storms and erosion, they provide jobs for local communities.
The net economic value of coral reefs is estimated to be in the tens of billions, according to the National Oceanic and Atmospheric Administration, so keeping them alive is not only essential for the wildlife they support, but the economy as well.
This story was reported from Los Angeles.