NOEL KING, HOST:
The federal government just launched an ambitious effort to try and preserve one of Florida's endangered coral reefs. It aims to restore 3 million square feet after decades of decline. Here's NPR's Greg Allen.
GREG ALLEN, BYLINE: Coral reefs around the world are hurting. For decades, warming and acidifying oceans, overfishing, declining water quality and disease have taken a toll. Nowhere is that more apparent than in the Florida Keys. Sarah Fangman is superintendent of the Florida Keys National Marine Sanctuary.
SARAH FANGMAN: People who have just been diving for a few years can see the changes that are happening on our reefs before our very eyes.
ALLEN: Working with marine science groups, NOAA has begun a long-term effort to bring the reefs back to something approaching their former glory. Work has now begun on a coral reef tract just off Key West. Divers have removed debris and invasive species and begun planting coral raised in land-based nurseries. Some of the work is being done by researchers and divers with the Mote Marine Laboratory. Mote CEO Michael Crosby says people who study coral reefs realized they had to act before it's too late.
MICHAEL CROSBY: That means is the coral reef itself, the corals, have dropped below the density levels that are required to continue to reproduce and maintain a healthy reef. They are sliding into functional extinction right before our eyes.
ALLEN: Mote now has two land-based nurseries in the Florida Keys where coral are bred and raised in shallow tanks where saltwater constantly circulates.
ALLISON DELASHMIT: This is a wet lab. I call this the nursery, though.
ALLEN: Allison Delashmit is with Mote Marine's Coral Reef Research Station on Summerland Key. Coral spawn just once a year. And when that happens, divers have to be on hand to collect the fertilized eggs and bring them back to the lab.
DELASHMIT: And it starts a very tenuous process where scientists are caring for these fertilized eggs, trying to get them to create larvae and then eventually settle.
ALLEN: Settling is the crucial phase when corals find a place to land and begin growing into individual genotypes. Mote Coral Lab science director Erinn Muller says as they mature, they're transplanted back onto reefs.
ERINN MULLER: Every year, we have thousands of new genotypes that we can put in the production line to get to the point where they're ready to go back out onto the reef. So not only are we increasing coral cover, we're increasing genetic diversity simultaneously.
ALLEN: The NOAA effort is targeting seven of the most important coral reefs in the Florida Keys. Researchers hope to restore 3 million square feet over the next decade. In the meantime, the stresses that have taken a toll on reefs aren't going away. They include a devastating problem that's affecting species throughout the Caribbean - stony coral tissue loss disease. Mote CEO Michael Crosby says researchers have developed disease-resistant genotypes that, once planted onto reefs, are thriving.
CROSBY: We have outplanted resilient genotypes five years ago of a very slow-growing coral that survived two coral bleaching events, a hurricane and stony tissue loss disease.
ALLEN: It's now grown to adult size and can reproduce on its own. Scientists hope to replicate that success one coral at a time as they begin restoring one of Florida's most endangered and valuable resources.
Greg Allen, NPR News, Miami.
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