ORLANDO, Florida – With simulated moonlight, ideal temperatures, and the soothing sound of bubbling saltwater.

A group of marine biologists prepared everything to create a romantic atmosphere for the corals in a tank. As the moment approached at the Florida Coral Rescue Center, the team was eager to see if their hard work would lead to coral spawning.

And their hopes were fulfilled. Over several nights, more than 75% of the center’s brain coral colonies reproduced, producing nearly half a million larvae.

In the wild, these fertilized larvae would drift for days or weeks before settling down on the ocean floor to grow into stone-forming corals. The larvae collected from the center are on their way to other restoration and research facilities, symbolizing a brighter future for coral reefs across Florida and the Caribbean.

“Our work here is critical to preventing extinction,” said Justin Zimmerman, a marine biologist at SeaWorld Orlando who manages both the rescue center and a newly established coral center in the theme park that mimics conditions found underwater in the Florida Keys.

Zimmerman is part of a dedicated group of marine biologists and scientists across various organizations striving to safeguard corals, which are facing unprecedented threats like damaging marine heat waves and a severe disease. These groups focus on growing corals, protecting at-risk species, and establishing gene banks.

Coral reefs in Florida and the Caribbean have faced severe challenges over the years due to pollution and increasing temperatures. The situation worsened with the introduction of stony coral tissue loss disease in 2014, which severely impacted corals along Florida’s reefs. Recently, significant losses were witnessed in these reefs and Australia’s Great Barrier Reef due to a global bleaching event caused by record-breaking marine heat waves.

The corals cared for at the rescue center, saved from the advancing disease near the Florida Keys, now carry the potential for future restoration.

Located within an unremarkable industrial area, the center features large fiberglass aquariums housing diverse coral ecosystems, including small fish that provide essential nutrients, along with urchins and other marine life to replicate underwater environments. This initiative is a collaboration between SeaWorld, Disney, the Florida Wildlife Foundation, and additional partners, supporting 18 species of corals with a total of 524 individuals. Weekly teleconferences overseen by the Association of Zoos and Aquariums facilitate ongoing discussions about coral care.

These organizations are part of a larger collaboration with the Florida Fish and Wildlife Conservation Commission and the National Oceanic and Atmospheric Administration, working together to protect the reefs that stretch over 300 miles from north of Miami to the Dry Tortugas. Some groups focus on growing corals, while others transplant them into ocean nurseries or explore complex topics related to genetics, cryopreservation, and chemistry.

The collective goal is to one day generate a sufficient supply of healthy, genetically diverse corals that can rejuvenate the reefs, contingent upon halting the increase in ocean temperatures.

Understanding the Complexities of Corals

Globally, researchers are delving into the intricate characteristics of these organisms, which are essential to one of the planet’s most abundant ecosystems. Corals may cover about 1% of the world’s seabeds, yet they are home to over 25% of marine life in the oceans.

Andy Stamper, manager of Disney Conservation Science, has spent years as a veterinarian at Disney’s Animal Kingdom and Living Seas at Epcot. Amidst the corals at the rescue center, Stamper remarked on their complexity: “They are the most complicated animals I’ve ever encountered.”

“They encompass animal, vegetable, and mineral elements, and they rely on bacteria, fungi, and protozoa,” he explained. “All these organisms must work in harmony for a healthy coral polyp to thrive.”

He sees a connection between the cooperative efforts needed to sustain coral communities and the collaborative approach necessary for their preservation.

The center’s staff have mastered technologies to replicate natural sunlight and moonlight using multi-colored LED lighting, making the spawning cycles “very predictable,” according to Zimmerman.

During spawning, corals release bundles of eggs akin to Dippin’ Dots ice cream. Encased in a mucus shell filled with sperm, these pink bundles are as tiny as a piece of quinoa. The shell dissolves as they rise to the surface, allowing the sperm to swim and fertilize eggs from different colonies, leading to the development of larvae.

By early September, several other coral species had successfully spawned, including boulder coral, boulder star coral, and mountainous star coral. “It’s tremendously rewarding to witness the culmination of years of effort as these corals thrive,” Zimmerman expressed.

Cultivating and Replanting Corals

Coral research has progressed significantly since Ken Nedimyer, often referred to as the pioneer of coral restoration, learned to cultivate corals in the Florida Keys over twenty years ago, according to Stamper.

Projects vary from advanced high-tech methods to simple, volunteer-friendly techniques. Jessica Levy, director of restoration strategy at the Coral Restoration Foundation, emphasizes the importance of community involvement in these efforts.

The Foundation recruits volunteers from Florida and the Caribbean to help connect coral pieces to specially designed underwater “coral trees” and set them up in coral nurseries along the reefs.

They focus on over 20 coral species, aiming for “cost-effective, impactful projects” that engage local communities. “Incorporating more diversity enhances resilience in restoration projects since different corals, even within the same species, react uniquely to various stressors,” Levy explained.

Hybridization and Cryopreservation Techniques

Between 2015 and 2024, wild Atlantic pillar corals experienced a staggering 97% decline in Florida, primarily due to stony coral disease. Currently, only about 24 live pillar coral colonies exist in the Keys.

The Florida Aquarium, which also participates in coral breeding, is home to 170 endangered pillar coral colonies. A collaborative team of international experts is exploring cryopreservation methods to keep coral larvae alive in liquid nitrogen for extended periods.

If successful in raising frozen and thawed larvae, it would mark a historic milestone as the first instance of scientists successfully cryogenically preserving coral larvae followed by their cultivation, the aquarium shared. This would allow for larvae to be revived decades or even centuries later.

The Florida Aquarium, along with the University of Miami’s Rosenstiel School and Mote Marine Laboratory, is working to crossbreed corals, specifically the federally threatened elkhorn and staghorn varieties, to create genetically enhanced corals that are more robust against heat and disease.

NOAA, the aquarium, and numerous other organizations collaborate with Secore International, a nonprofit focused on reef restoration that provides training for sexual coral propagation techniques.

After producing coral larvae, the next hurdle is encouraging them to settle. Amy Wagoner Johnson, a professor at the University of Illinois’ Grainger College of Engineering, leads a global research effort to discover materials that create optimal surfaces for attracting and aiding the settling of coral larvae. She and her team are experimenting with these materials at Curaçao’s CARMABI research station.

The specialized surface material resembles mortar, enhanced with specific additives and then pressure-treated to carbonate and strengthen it. When submerged, these substrates release ions that seem to attract coral larvae.

The Importance of Corals

Coral reefs are vital components of the ocean’s food chain, providing habitat for various organisms like worms and shrimp. They serve as homes for fish that are essential for human consumption, bolster local tourism economies significantly, and offer critical protection against storm waves for coastal areas.

Corals are essential for sustaining the livelihoods of millions worldwide, according to Alice Grainger, who is the senior director of creative development at the restoration foundation. She stated, “Even after setbacks like we experienced last year, we must not abandon the communities that depend on these ecosystems for their survival and way of life.” “Losing these ecosystems could lead to the decline of coastal communities,” she cautioned.

Understanding Coral Bleaching

Corals appear vibrant on the ocean floor due to their relationship with symbiotic algae called zooxanthellae, which reside within the coral polyps. These algae provide corals with their array of colors, using sunlight to create sugars and proteins, while also assisting in waste removal.

When water temperatures surpass 90 degrees for extended periods, it stresses the algae, prompting them to release harmful byproducts. As a result, coral polyps expel the stressed algae, causing the corals to lose their color and vitality, leaving behind only the transparent polyps.

The white limestone buildings they have constructed still stand, creating a “bleaching” effect.

What lies ahead for coral restoration?

According to Wagoner Johnson, safeguarding and rejuvenating coral reefs is “a very complex challenge.” However, he believes that it’s premature to lose hope.

Bill Precht, a scientist based in Miami who penned the first book on coral restoration in 2006, emphasized that the ongoing critical projects are invaluable for advancing scientific knowledge, which is crucial for giving corals more time to recover.

“We have made incredible strides in our efforts,” remarked Precht. “With advancements in microbiology and genetics in the future, we’ll accomplish tasks we can’t even envision right now.”

Precht, along with others, questions whether trying to transplant corals onto reefs is a lost cause while climate change and greenhouse gas emissions continue to cause significant increases in ocean temperatures. Even if humanity manages to mitigate global climate change, he worries it may take 50 to 100 years for ocean temperatures to decrease enough for corals to thrive once more.

Stamper pointed out that similar to the collaborative environments where corals flourish, it will require humans and various organizations “joining forces to restore these corals.” He stated, “If any species can recover, it’s the corals.”

Dinah Voyles Pulver, a national correspondent for YSL News, has reported on climate change, wildlife, and the environment for many years. You can follow her on Twitter @dinahvp.