A team of researchers recently announced that they’ve made a breakthrough with a futuristic solution for saving coral reefs from disappearing from our oceans. Deep freezing pieces of coral and then bringing them back to life.
In a study recently published in the journal Nature Communications, the team of scientists describes how they successfully revived fragments of adult Hawaiian coral after deep freezing it.
The researchers placed the pieces of coral in a rigid aluminium container filled with a solution. They rapidly cooled the container with liquid nitrogen to -196 degrees Celsius. The quick cooling meant that ice crystals were less likely to form, which helped avoid tissue damage. This allowed scientists to successfully thaw the mature coral fragments. Once the container was warmed again, the coral fragments were put into seawater and allowed to recover from their deep freeze. For 24 hours after being thawed, researchers observed that the previously frozen coral consumed oxygen at a comparable rate compared to coral that was never cooled.
The ability to freeze parts of adult coral is especially exciting to the researchers because scientists have previously preserved younger coral cells, like coral larvae and coral sperm. But corals spawn only a few days a year, so collecting that genetic material is challenging. Having the option to deep freeze living adult coral would support larger conservation efforts.
“If we can scale this up and refine the post-thaw husbandry [care and cultivation of coral], we will be able to work year-round rather than just a few days during spawning seasons,” Mary Hagedorn, a study author and research biologist at the University of Hawaiʻi at Mānoa, said in a press release. “If we can do that, this will be a really viable process that changes how we see the security of corals going forward.”
The climate crisis is making it harder for coral reefs to thrive, worrying conservationists worldwide. Coral reefs are often in warmer parts of the planet including off the coast of Australia, in the Caribbean, and near Hawaii. But as the climate crisis makes the planet hotter, ambient air and ocean temperatures have climbed. And this year has seen record heat, especially this July and August. And when seawater temperatures rise too much, corals expel the algae responsible for their colour. Bleached coral is weaker which makes it more susceptible to disease.
Some coral reefs do not recover from large bleaching events. Two that occurred in 2014 and 2015 near Hawaii had high mortality rates, according to a report from the National Oceanic and Atmospheric Administration (NOAA). Coral reefs have taken thousands of years to build up and are home to a wealth of marine biodiversity. Though they only make up about 1% of the ocean, around a quarter of marine life make their homes in and around coral reefs, according to NOAA.
And despite global efforts to protect corals, they’re still declining. A 2021 analysis from the Global Coral Reef Monitoring Network found that warming oceans contributed to mass bleaching events that killed 14% of its coral between 2009 and 2018. But with the recent breakthrough in freezing and reviving adult coral pieces, there is some hope that coral reefs won’t disappear. The team of scientists is now assessing if this freezing method can be used to achieve long-term survival of the adult coral fragments. They also want to reduce the stress placed on the coral cells.
Matthew Powell-Palm, a professor at Texas A&M University and lead author of the study, said that this process is simple. And it allows the freezing method to be replicated by conservation teams around the world. “It requires no moving parts or electronics,” he told Texas A&M Today. “This is essential to the practicality of any conservation technique because when this is deployed in real marine field stations, the high-tech lab infrastructure common to many laboratories will not be available.”
There are other efforts underway to protect coral reefs, including in the Florida Keys. Scientists at the Keys Marine Laboratory at the Florida Institute of Oceanography have moved over 1,000 pieces of coral into lab nurseries to protect critical marine environments.