Saving Florida’s Barrier Reef

VIRGINIA KEY, Fla. (June 5, 2019) – Marine biologist Andrew Baker plunges his right hand into the massive saltwater-filled tank and picks up of a softball-sized chunk of grooved brain coral, holding it at eye level to show what a healthy specimen of this particular species looks like.

Chiseled from a reef in the Marquesas Keys, the sample is among 340 other corals that are thriving in three 20-foot-long outdoor tanks at the University of Miami’s Experimental Hatchery on Virginia Key.

Their watery refuge is only temporary, though. These corals are harbingers of hope—robust specimens that are part of an ambitious rescue mission to save the Florida Reef Tract, as a mysterious disease continues to ravage what is the only barrier reef in the continental United States.

Since early May, scientists from UM’s Rosenstiel School of Marine and Atmospheric Science and other agencies have collected hundreds of corals from outside the disease zone, bringing them to the UM hatchery, where they are cared for to preserve their genetic diversity for future transplantation and potential breeding.

The rescue effort is the first of its kind.

“This is usually the last thing that any conservation management agency wants to do—the direct removal of corals from the reefs,” said Baker, an associate professor and coral reef expert at the Rosenstiel School, who is leading UM’s component of what is called the Florida Reef Tract Rescue Project. “Everything is usually about conserving, growing, leaving intact, and protecting the reef—a generally hands-off approach. But the situation has become so dire that for the first time ever, management agencies have agreed to coordinate a rescue effort to collect up to 3,000 colonies of 15 different species and put them into land-based coral facilities with the overall goal of eventually restoring them, or their offspring, back to the reefs.”

The project is being spearheaded by the Florida Fish and Wildlife Conservation Commission and the National Oceanic and Atmospheric Administration (NOAA).

The epizootic, known as stony coral tissue loss disease, has affected up to 23 different species of coral along the Florida Reef.

“In Florida, we have only about 50 or 60 coral species,” said Baker. “So we have almost half the species on the reef being affected by this disease, including some of the really important ones.”

By some estimates, it has killed tens of millions of corals, making it one of the most lethal coral diseases on record anywhere in the world, according to Baker.

And what’s worse, the disease, unlike other coral diseases, hasn’t cleared up during the winter season, enduring even when cooler temperatures set in. “Coral diseases tend to occur in the summer months, when warmer temperatures increase the growth rates of bacteria and other pathogens,” said Baker. “You get this short spike of a few months where the disease is prevalent, and then it usually burns itself out. But this disease has been continuously affecting Florida’s reefs for almost five years now.”

And that’s even more bad news for corals, which are already under assault from bleaching and ocean acidification caused by climate change.

Scientists have yet to pinpoint what’s causing the disease. Bacteria that can be transmitted to other corals through direct contact and water circulation may be responsible, NOAA reports on its website.

“It does seem to respond to antibiotics, suggesting that it’s bacterial,” said Baker. “But we don’t yet have a causative agent, a pathological smoking gun.”

The disease started in 2014 off Virginia Key, and since then has spread south, past Key West, heading towards the Marquesas in the direction of the Dry Tortugas. It has reached as far north as Martin County, north of Jupiter. And late last year, it was documented in places as far away as Mexico, the Dominican Republic, the U.S. Virgin Islands, and Jamaica. “So it seems that it’s spreading out of this area,” said Baker.

For now, the coral rescue mission, in which UM is playing a key role, seems to be the best hope at stopping the disease in its tracks.

On a recent Wednesday morning at UM’s Experimental Hatchery, Baker showed up to check on the health of the corals, meeting with two of his graduate students who are involved in the project.

“We’re exceptionally lucky,” he explained. “We have running tropical seawater, while most of the other facilities to which we will be shipping these corals have closed systems and are using artificial seawater that’s re-circulated around the tank.”

But along with the benefit of providing a saltwater sanctuary for the specimens comes the challenges of being located in the disease zone. So Baker and his team have instituted an added layer of protection, filtering and sterilizing the seawater that’s piped in.

“So far, so good,” said Baker, noting that they haven’t lost any of the 340 corals at the hatchery.

The specimens will eventually be transferred to a network of public zoos and aquariums around the nation, where they’ll become part of a series of public exhibits and educational outreach efforts—all the while being conserved for future transplantation.

Another collection of corals will arrive at the hatchery in early July, when a chartered liveaboard vessel with scientists from NOAA, UM, and the Florida Fish and Wildlife Conservation Commission returns from the Dry Tortugas carrying specimens free of the disease.

It will be the third such expedition. A second voyage delivered samples to Nova Southeastern University, which is also partnering in the project.

Carly Dennison, a new Rosenstiel School doctoral student who was on the previous two research cruises, will be a diver on the third trip, diving as deep as 60 feet to retrieve healthy corals.

She and a team of dive buddies will gather corals between ten and 30 centimeters in diameter. “What’s really important is choosing the best and the brightest, those corals that will likely survive and be reproductive,” said Dennison.

Once at the hatchery, they’ll be dipped in a special solution to remove any foreign bacteria or parasites. David Ehrens, a master’s of professional science student in tropical marine ecosystem management, will be their primary caretaker. “It’s pretty much a seven-day-a-week job,” he said. “But I love doing it.”

Marine biologist Baker calls coral reefs “warehouses of diversity.”

“People think of them as the rainforests of the sea,” said Baker, noting that corals also help protect coastlines from the damaging effects of storm surge. “There are more species found in these ecosystems than in any other marine ecosystem on the planet. By some estimates, somewhere between a quarter and a third of all the world’s marine fish species depend on coral reefs at some part of their lifecycle. So they’re important for biodiversity conservation. And if we lose them, we lose all of the attendant species that use these corals as their habitat.”

Photos/Video: T.J. Lievonen/University of Miami, and Diana Udel/Rosenstiel School of Marine and Atmospheric Science