In a bid to protect coral reefs from bleaching due to rising temperatures, scientists in Australia claim to have developed a more 'heat-resistant' coral.
Coral bleaching occurs when corals expel the colourful microalgae which live inside them, and supply them with nutrients, due to rising temperatures amid climate change. This turns the corals white and they starve to death.
However, scientists at Australia's Commonwealth Scientific and Industrial Research Organisation (CSIRO) have now claimed to develop a lab-grown strain of microalgae, which is more tolerant to heat.
"Climate change has reduced coral cover, and surviving corals are under increasing pressure as water temperatures rise and the frequency and severity of coral bleaching events increase," CSIRO Synthetic Biology Future Science Platform (SynBio FSP) science lead Dr Patrick Buerger said in a statement.
"Our novel approach strengthens the heat resistance of coral by manipulating its microalgae, which is a key factor in the coral's heat tolerance," Dr Buerger added.
The researchers isolated the microalgae from coral and cultured them to increasingly warmer temperatures over a period of four years. This helped the algae 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," Dr Buerger said.
"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.
Oppen added that these "exciting findings" indicate that the coral and the microalgae 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.
"This breakthrough provides a promising and novel tool to increase the heat tolerance of corals and is a great win for Australian science," SynBio FSP Director Associate Professor Claudia Vickers said.
The research was conducted by CSIRO in partnership with AIMS and the University of Melbourne.
Earlier this year, Australia's Great Barrier Reef had suffered a mass bleaching event, due to warmer temperatures, especially in February. This was the third event in just five years and caused a huge coral loss. Two-thirds of the reef was damaged by similar events in 2016 and 2017.