This article has been reviewed according to Science X's editorial process and policies. Editors have highlighted the following attributes while ensuring the content's credibility: Throughout the first week of August, 12 organizations came together in an unprecedented collaborative effort to protect the future of Florida's Coral Reef during one of nature's most elusive events: coral spawning. Scientists across the organizations worked tirelessly to propagate and conserve the next generation of corals by collecting eggs and sperm (gametes), strategically fertilizing embryos and cryopreserving sperm to safeguard invaluable genetic diversity for generations to come.
Coral spawning is exceedingly rare, occurring once a year within a narrow window dependent on lunar cues and environmental conditions. Just after 10 p.m., corals begin synchronized breeding, releasing millions of egg and sperm bundles simultaneously. The bundles must encounter other bundles of the same species for fertilization to occur.
But after decades of decline, coral colonies have become so sparse and widely dispersed that the bundles often cannot find one another in the water, making natural reproduction increasingly difficult and leaving some species functionally extinct in Florida. Now, fewer than 150 unique elkhorn corals and 300 staghorn corals remain on Florida's Coral Reef—just 1% of their former abundance. But scientists are not giving up.
Dive teams collected millions of gametes from elkhorn and staghorn corals at offshore nurseries operated by Reef Renewal U.S. and Mote Marine Laboratory near Key Largo. The gametes were then rapidly transported to a temporary laboratory at John Pennekamp Coral Reef State Park through a partnership with Mote Marine Laboratory, where experts across organizations determined desirable genetic crosses to create fertilized embryos most likely to prove resilient to environmental stressors. Concurrently, another team worked to cryopreserve additional sperm for future restoration purposes.
"This project aims to incorporate innovative approaches into coral restoration while also bringing together many years of experience with coral spawning that is dispersed across several institutions working on Florida's Coral Reef," said Andrew Baker, principal investigator of the grant and a professor in the Department of Marine Biology and Ecology at the University of Miami Rosenstiel School. "Our reef is in trouble, and we need to take urgent action to scale up efforts to help restore and rebuild one of the state's most valuable environmental and economic resources." Over seven days, scientists observed 25 elkhorn genotypes and 36 staghorn genotypes spawning, resulting in 116 unique directional crosses using assisted fertilization. The scientists ultimately produced more than 1.5 million embryos, resulting in more than 61,000 elkhorn larvae and 47,000 staghorn larvae divided between the University of Miami Rosenstiel School, Mote Marine Laboratory, The Florida Aquarium, The Reef Institute and the Smithsonian Marine Station.
The organizations will continue nurturing and growing the larvae and, within two years, return the new corals to the same nurseries before finding permanent homes on nearby reef sites, including Mission: Iconic Reefs locations in the Florida Keys National Marine Sanctuary and the Kristen Jacobs Coral Aquatic Preserve. "What we have done over a few weeks would never have happened without human intervention," said Celia Leto, senior biologist and manager of the Coral Reproduction Laboratory at Mote Marine Laboratory. Discover the latest in science, tech, and space with over 100,000 subscribers who rely on Phys.org for daily insights. d research that matter—daily or weekly.
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