A team of Australian scientists has successfully developed a coral more resistant to increased seawater temperatures in a laboratory setting in a bid to fight deadly coral bleaching due to global warming.
The development was first reported by the scientists in a peer-reviewed article in the Science Advances journal on Thursday.
Coral reefs' decline has accelerated across the world in recent years due to climate change-related bleaching and other natural phenomena, as well as manmade problems. Coral bleaching occurs when a natural phenomenon, like a rise in sea temperature or acidification, damages microscopic algae – living organisms inside the corals that provide them energy and give them their vibrant colors.
Scientists say if corals have increased heat tolerance, they have the potential to reduce the impact of reef bleaching from marine heat waves, which are becoming more common under climate change.
The researchers were able to make the coral more tolerant of temperature-induced bleaching by bolstering the heat tolerance of its microalgal symbionts – tiny cells of algae that live inside the tissue of the coral.
The team isolated the microalgae from coral and cultured them in the specialist symbiont lab at the Australian Institute of Marine Sciences (AIMS). They then exposed the cultured microalgae, using a technique called "directed evolution," to increasingly warmer temperatures over a period of four years, which assisted the corals 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," said Patrick Buerger, lead science researcher at the Commonwealth Scientific and Industrial Research Organisation (CSIRO), an Australian government agency.