Scientists have successfully developed heat-resistant coral. Corals with increased heat tolerance have the potential to reduce the impact of reef bleaching from marine heat waves, which are becoming more common under climate change.
The research team made the coral more tolerant to temperature-induced bleaching by bolstering the heat tolerance of its microalgal symbionts – tiny cells of algae that live inside the coral tissue.
“Our novel approach strengthens the heat resistance of coral by manipulating its microalgae, which is a key factor in the coral’s heat tolerance,” explained science lead Dr Patrick Buerger in a statement.
The team isolated the microalgae from coral and cultured them. Using a technique called “directed evolution”, they then exposed the cultured microalgae to increasingly warmer temperatures over a period of four years. This assisted them to adapt and survive hotter conditions.
“Once the microalgae were reintroduced into coral larvae, the newly established coral-algal symbiosis was more heat tolerant compared to the original one,” explained Dr Buerger.
The microalgae were exposed to temperatures that are comparable to the ocean temperatures during current summer marine heat waves causing coral bleaching on the Great Barrier Reef.
The researchers then unveiled some of the mechanisms responsible for the enhanced coral bleaching tolerance.
“We found that the heat tolerant microalgae are better at photosynthesis and improve the heat response of the coral animal,” Professor Madeleine van Oppen, of AIMS and the University of Melbourne, said in the statement. “These exciting findings show that the microalgae and the coral are in direct communication with each other.”
The next step is to further test the algal strains in adult colonies across a range of coral species.
Image credit: Sarah Depper, flickr/Creative Commons