Scientists are one step closer to perfecting a method that could save hundreds of coral species from extinction.
Researchers at the Hawai‘i Institute of Marine Biology have successfully cryopreserved and revived entire fragments of coral.
They employed a technique called isochoric vitrification, which preserves coral samples in a "glassy state." This method prevents the formation of ice crystals that could otherwise damage the corals' cells.
Trials showed that the corals were still alive when thawed 24 hours later. It's the first time coral polyps in their calcium carbonate skeleton have survived cryopreservation.
Mary Hagedorn is the senior research scientist at the Hawaiʻi Institute of Marine Biology. She's been working to develop this technique since 2019.
She said the process has tremendous potential, but there are still some kinks to work out. Right now, it's very stressful for the coral.
"It's like a patient that goes through open heart surgery," said Hagedorn. "It's successful, but you can't walk home after that. You've got to stay in the ICU."
Cryopreservation is already a common tool in coral preservation. But all the current cryopreservation protocols are dependent on reproductive cycles, said Hagedorn, as scientists had previously only been able to freeze simpler cells like sperm and larvae.
That meant that scientists had a limited window to collect specimens, as corals spawn once a year. And those cycles are becoming more erratic as ocean temperatures rise and stress reefs.
"We wanted another method that would allow us to go out almost every day," Hagedorn said.
The breakthrough with isochoric vitrification will accelerate efforts to bank samples of coral species at risk of extinction, and thus preserve the genetic diversity of reef ecosystems.
"Is it a reef? No," said Hagedorn. "But it is enormous amount of security to have those individuals and those species put away for now."
Hagedorn expects scientists will be able to employ this method broadly in the next two years.
