Florida’s coral reefs are critical to the state’s economy. They protect beaches and play a vital role in supporting thriving fisheries. However, time may be running out to witness some types of live coral in the Florida Keys. A severe heat wave in the summer of 2023 killed many species, and stony coral tissue loss disease has been particularly devastating to Atlantic pillar coral.
The pillar coral population has decreased by 97% in Florida’s Coral Reef over the past decade, leaving only 24 living colonies. Keri O’Neil, director and scientist of the Florida Aquarium’s coral conservation program, noted that pillar coral is the most threatened coral species in the state.
"Between disease and bleaching, we've experienced significant coral mortality over the past 10 to 15 years," she said.
O’Neil is collaborating with researchers from Mexico, Australia, Hawaii, and a scientist from the University of South Florida to cryopreserve pillar coral larvae using liquid nitrogen, in hopes of preventing the species' extinction.
"If we freeze tens of thousands of larvae, that potentially represents tens of thousands of corals that could be thawed and grown in the future," O’Neil said.
"We can plant corals back on the reefs now, but we don’t know what will happen in the next five, 10, or 20 years. Many of the corals replanted on the reefs might not survive. By freezing these larvae, we can preserve them for hundreds of years."
O’Neil is optimistic that, generations from now, these preserved larvae can be thawed, grown in labs, and replanted on reefs. The ultimate goal is to create a frozen gene bank for coral.
This freezing method has previously been used on coral sperm or small tissue samples, but cryopreservation for coral larvae is still in its early stages.
The team is working to prevent ice crystals from forming inside the larvae, which would ruin the preservation process. They are using chemicals called cryoprotectants and transferring larvae into petri dishes using pipettes. The larvae are then placed on a stainless-steel mesh that allows for rapid warming after freezing.
Afterward, the larvae are dipped into liquid nitrogen, creating a visible plume. The scientists then warm them up and observe if they are still swimming.
"It’s been a team effort, with about eight or nine of us huddled around a massive table, pipetting larvae, testing different chemicals, and taking notes,” O’Neil said.
The next step for this project is scaling up the process, as the international coral problem is immense. The team plans to publish their recent findings and continue experiments over the next few years, supported by a grant from the Coral Research and Development Accelerator Program.
Image: A scientist using liquid nitrogen to freeze coral larvae. Credit: Florida Aquarium
Source: WLRN
