It’s a historic step forward, and they hope it could help revitalize Caribbean ecosystems and give back to people by offering extra protection from the fury of hurricanes. Elkhorn corals once dominated the Caribbean. But just as other vital coral ecosystems are being degraded around the world, the elkhorn is rarely seen alive in the wild anymore. This species – so important because it provides the building blocks for reefs to thrive – has until now been very difficult to grow in aquariums. That’s why the scientists were thrilled to see that their breeding experiment was successful. “When it finally happened, the first feeling was pure relief.” said Keri O’Neil, the senior scientist who oversees the Tampa Aquarium’s spawning laboratory. “This is a critical step in preventing the extinction of elkhorn corals in the state of Florida.” O’Neil’s colleagues call her the “coral whisperer” because she has been able to breed so many varieties of coral. Elkhorn marks the 14th aquarium species born inside the Apollo Beach lab, but the team ranks it as its most important. O’Neil estimates there are only about 300 elkhorn corals left in the Florida Keys reef area — but the spawning experiment produced thousands of corals. He expects as many as 100 of them could survive to adulthood. Named for its resemblance to deer antlers, the coral thrives on top of reefs, usually growing in water depths less than 20 feet. This makes their colonies critical for breaking large waves. During peak hurricane season, reefs are a silent but powerful ally that protects Florida’s coast from storm surges, which grow larger as sea levels rise. “As these reefs die, they start to erode and we lose that coastal protection as well as all the habitat that these reefs provide for fish and other species,” O’Neil said. “Now there are so few left, there are only a few scattered colonies. But we’re really focusing on restoring the elkhorn coral population for coastal protection.” The news about the Florida Aquarium comes after scientists reported in early August that the Great Barrier Reef had the largest extent of coral cover in 36 years. But the outlook for corals around the world is bleak – studies have shown that the climate crisis could kill all of Earth’s coral reefs by the end of the century. The Elkhorn coral was listed as federally threatened under the US Endangered Species Act in 2006 after scientists found that disease has reduced the population by 97% since the 1980s. And ocean warming is the biggest threat . As the ocean temperature rises, the coral expels the symbiotic algae that live within it and produces nutrients. This is the process of coral bleaching and usually results in the death of the coral. “They’re dying all over the world,” O’Neil told CNN. “We’re at a point now where it may never be the same. You can’t have ocean fever every summer and not expect there to be an impact.”
“YOU KNOW IT’S IMPOSSIBLE”
Elkhorn corals seem to have something akin to a fertility problem. Its reproduction is sporadic in the wild, making it difficult to sustain a much-needed population increase. Due to their low reproductive rate, genetic diversity can also be very low, making them more susceptible to disease. “You could say they are successfully having sex, but they are not successfully making babies [in the wild]O’Neil said. “Land animals do this all the time. “When you have an endangered panda or chimpanzee, the first thing you do is start a breeding program, but coral breeding is extremely strange.” The hardest part for O’Neil’s team was doing the unprecedented – getting the coral to be born in a lab. O’Neil said other researchers doubted they could pull it off. “We faced a lot of criticism from people,” he said. They would say “”you can’t keep them in an aquarium. You know it’s impossible!” They were right. At first. Elkhorn coral only reproduces once a year. In the lab’s 2021 experiment, the environment was tightly controlled to mimic natural conditions. Using LED lights, they accurately mimicked the sunrise, sunset and moon cycles. But the coral was not born. “We realized the moonrise was off by about three hours,” O’Neil said. After this disappointing setback, aquarium scientists knew they had a much better shot this year. And, with the support of the National Oceanic and Atmospheric Administration Restoration Center and the National Fish and Wildlife Foundation, the Florida Aquarium in August did what some peers thought was impossible. The spawning could be a game-changer, according to Thomas Frazer, dean of the College of Marine Sciences at the University of South Florida, and could lead to a future where corals are more resilient to the dramatic changes brought about by the climate crisis. “This kind of work really matters,” Frazer told CNN. “Corals selected for restoration may, for example, be more resistant to warmer ocean temperatures and bleaching, exhibit skeletal properties that are able to withstand more intense wave energy, or traits that may make them more resistant to disease or other environmental stressors’. Margeret W. Miller is a coral ecologist who has focused on restoration research for more than two decades. Miller co-authored a 2020 study that found the rate of reproduction of elkhorn in the Upper Florida Keys was so low, it would indicate the species was already “functionally extinct” and could be wiped out in six to 12 years. Miller said the Florida Aquarium’s discovery will open new doors to tackle the larger restoration effort. “Because this species is an important recovery target, the ability to spawn under human care opens up many research opportunities to develop interventions that could make recovery efforts more resilient to climate change and other environmental threats,” Miller told CNN. Miller said more research needs to be done to ensure lab-bred elkhorn corals are safe and effective enough to be used in the conservation of the species. “This type of captive spawning is not a tool that directly addresses widespread global coral restoration that will meet the scale of the need. Indeed, no current coral restoration efforts meet this scale, and none will truly succeed unless we can take serious action to ensure that coral reef habitats can remain in a sustainable state where corals can thrive,” Miller told CNN. The climate crisis is the ultimate problem to be solved, Miller said. Rapid ocean warming must be addressed, along with threats to water quality. Still, he said, the ability to grow acorns in a lab is an important tool in the recovery effort. “Coral propagation research and the interventions that can be enabled by captive spawning efforts can, however, buy time to make such changes effectively before corals disappear completely from our reefs,” Miller said.
BUY TIME
Elkhorn branches can grow up to five inches a year, making it one of the fastest growing coral species, according to NOAA. And based on observations from Florida Aquarium scientists, their new baby elkhorn corals will take three to five years to reach sexual maturity. Within a year or two, scientists plan to replant these lab-grown corals in the Florida Keys National Marine Sanctuary. In the fight to restore reefs, scientists agree that this discovery is only a first step. “We’re really buying time,” O’Neil said. “We’re buying time for the reef. We’re buying time for the coral.” The ultimate goal is a breeding program where scientists could select for genetic diversity and breed more resilient corals capable of withstanding threats such as pollution, warming ocean waters and disease. Then nature can take the wheel. “There is hope for coral reefs,” O’Neil said. “Don’t give up hope. All is not lost. However, we must make serious changes in our behavior to save this planet.”
