Regrowing Florida’s Coral Reefs



Climate change and disease have decimated the Keys’ coral reefs. But a lab has pioneered a process to accelerate their regrowth … and prioritize climate-resilient corals.

After feral lab monkeys had been confined for years to an uninhabited island in the Florida Keys and had eaten the leaves off all the island’s mangroves, a judge ordered the voracious primates removed in 1998. Researchers tasked with restoring the mangroves set up a facility and learned how to grow the trees quickly and on a large scale. 

Why wouldn’t this work for corals? one of the researchers reportedly asked. Today, inside the Elizabeth Moore International Center for Coral Reef Research and Restoration on Summerland Key (the first category five hurricane-proof building in the Florida Keys), scientists at the non-profit Mote Marine Lab are learning to grow indigenous corals at lightning speed. Their goal is to repopulate depleted coastal reefs as quickly as possible. 

Florida Keys coral reef.
The Florida Keys coral reefs are considered functionally extinct.

By the 2010s, the Florida Keys region had lost at least fifty percent of its reefs. Then, in 2018, a coral disease showed up in the Keys, reducing living coral to barely one percent of its original levels. This rendered it functionally extinct, meaning that it would be unable to recover naturally. Human intervention was necessary. 

Taking me through Mote Labs, Allison Delashmit, Director of Regional Operations, hands me a disk of coral the size of a quarter. In a room filled with aquariums and shallow tabletop pools called raceways, a surprisingly young scientist shows me how to use a bandsaw to cut the disk into four pieces. 

“Mote pioneered a process called micro-fragmentation,” Delashmit explains. “Cut coral acts similar to what happens when we cut ourselves. Our skin will go into overdrive and [rapidly] create brand new skin. Cut coral grows fifty to sixty times faster than it would naturally. It will grow in six months what would take five to twenty-five years [to grow] in the wild.”

Delashmit leads us outside, where rows of raceways are filled with corals in various stages of growth. My little pieces of cut coral will grow here until they are the size of pepperoni slices. Then they’ll be ready for planting in the wild.

“We find a dead coral head, scrub it down, drill holes in a pepperoni pizza pattern, and stick these plugs in the holes,” Delashmit says. The corals grow quickly, spreading from the plugs across the dead coral. When two pieces of new growth touch each other, they fuse to create a solid mass. 

“We’re aiming for dinner plate size,” Delashmit says. “That’s the size it takes corals to become sexually reproductive. We can do that in about two years, when it would normally take twenty-five to a hundred years.”

Allison Delashmit, Director of Regional Operations, at the Mote Marine Laboratory's outdoor coral raceways.
Allison Delashmit, Director of Regional Operations, tours the Mote Marine Laboratory's outdoor coral raceways.

Here’s where Mote’s second significant advance comes in. Scientists can outplant all the corals they want, but those corals will be just as vulnerable to the stressors that killed their predecessors, even if they do reach reproductive size. Mote scientists knew they had to propagate strains that would be resilient in the face of climate change. As Delashmit says, “Genetic diversity is essential to our success.” 

Back inside, Delashmit takes us through the process of speeding up evolution, beginning in a special lab. “You’ve just entered my favorite room in the whole facility,” she says: “the coral baby nursery. Let’s talk coral sex.” 

“Corals spawn at the same time once a year, usually in August around the full moon,” she says. During a seven-day window, Mote scientists don red headlamps (bright light interferes with the reproduction cycle) and wait for the moment when captive corals release bundles of polyps that rise to the water’s surface. 

“It looks like reverse snow in the water,” Delashmit says. “As soon as they hit air, they break open to reveal eggs and sperm, which have twenty minutes to an hour to find another egg or sperm.” Mote scientists already know which corals they want as parents, because they’ve tested them in their Climate and Acidification Ocean Simulator (CAOS), or selected them from earlier outplanted parents that have survived hurricanes, disease, and bleaching. When the corals spawn, eggs and sperm from the selected parents are placed in the same tank. 

A staff member analyzes photos and data at Mote Marine Laboratory.
A staff member analyzes photos and coral data at Mote Marine Laboratory.

When the larvae hatch, Delaschmit explains, “We sprinkle them with what I call pixie dust, a coral friendly algae vital to growth.” She says the success of this breeding process has made Mote a beacon of hope for the reef. Last year, Mote outplanted 40,000 climate-change-resilient corals — bringing the total to about 200,000 with a survival rate of over ninety percent — and they’re expanding to two other locations in the Keys. 

“We continue to scale up,” she explains. “The reef doesn’t have enough time, so we’ve got to go as fast as we can.” Of Florida’s seventeen coral species, Mote currently works mainly with six, but they hope to learn how to propagate all of them. 

As the tour wraps up, Delashmit concludes: “I hope the takeaway is that our reef is in trouble, and it’s going to take everyone working together to save it, but we can save it. I don’t know if you’ve noticed, but every scientist here is young. They come here every day in the belief that they’re going to make a difference not in their lifetimes, but for their grandchildren in their lifetimes.” 

Read more dispatches from around our pale blue dot:

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Darcy Rhyno
Darcy Rhyno
Darcy Rhyno has penned hundreds of articles on everything from white water rafting in Costa Rica to the wild horses of Sable island. He's published two collections of short stories, two novels, stage and radio plays, and two non-fiction books, including his most recent, Not Like the Stars At All, a memoir about life in the former Czechoslovakia.
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