Rahul SomvanshiEight leading marine research institutions have joined forces in the Florida Keys to test cutting-edge methods that might help corals survive in warming oceans. The research happens during the ongoing Fourth Global Bleaching Event, which has already exposed 84% of the world’s reefs to bleaching-level heat stress.
Coral Race Against Time
The partnership combines Coral Restoration Foundation™ (CRF™) with its extensive coral stock and field infrastructure, and Shedd Aquarium with its mobile research vessel, the Coral Reef II.
“This collaboration is where all that groundwork meets the most innovative science in our field,” said Phanor Montoya-Maya, Restoration Program Manager at Coral Restoration Foundation™. “In the face of the greatest threat reefs have ever known, this work is not just about protecting biodiversity — it’s about proving that we still have time to turn the tide.”
Nursery-to-Lab Pipeline
The experiments centered on CRF™’s Tavernier Nursery, the world’s largest open-ocean nursery. Within a dedicated “spawning alley,” researchers monitored 28 staghorn and 5 elkhorn coral genotypes. Of these, 27 staghorn and one elkhorn released gametes during the spawning event.
Scientists collected reproductive cells from 16 staghorn corals over three nights and transferred them to the Coral Reef II for immediate experimentation.
Four Key Experiments
- Direct Sea Fertilization: Teams from CRF™, University of Miami Rosenstiel School, University of Hawai’i Mānoa, and Shedd conducted assisted fertilization using fresh gametes. Success came when embryos appeared on August 13th and 14th, developing into tens of thousands of larvae. Half were moved back to the CRF™ nursery to settle on specially designed substrates from Capital Corals, Rebuilding with Nature, and Reef Arches.
- Heat-Resistant Algae Introduction: Coral bleaching occurs when heat stress forces corals to expel their symbiotic algae. Researchers introduced heat-tolerant algae species (not typically found in parent colonies but observed at the juvenile stage) to coral larvae under both normal and elevated temperatures to test whether this partnership improves survival during marine heatwaves.
- Temperature Tolerance Testing: Researchers exposed some larvae to controlled high-temperature treatments to identify individuals with naturally higher heat tolerance, allowing for more informed selection of coral genotypes for future restoration work.
- Stem Cell Transfers: Scientists transplanted stem cells from coral larvae into adult fragments to test whether this can enhance heat stress tolerance. This applies regenerative biology concepts to coral conservation.
Reef Restoration Progress
The approach helps overcome bottlenecks in land-based systems by shortening the time from gamete release to fertilization and eliminating transport stress on early life stages.
Following the severe 2023 bleaching event, which saw less than 22% of outplanted staghorn and 5% of elkhorn corals survive, restoration groups urgently pivoted strategies. There is now a greater focus on outplanting massive, slower-growing species like brain, boulder, and star corals, which demonstrated higher thermal resilience compared to branching species.
CRF™ continues to assist Shedd Aquarium and the Rosenstiel School in collecting wild spawn from Orbicella faveolata colonies at Horseshoe Reef, where CRF™ has outplanted more than 8,000 corals across seven species since 2015.
“Coral extinction and climate change are some of the most pressing issues facing our planet today, and we need to rapidly explore solutions from all sides if we want to save our oceans,” said Dr. Shayle Matsuda, research biologist at Shedd Aquarium.The work builds on a partnership between CRF™ and SEZARC that began in 2017 to safeguard coral genetic material.
