Clouds were moving across the sun and a 20-knot northeast wind was stirring a 3-foot chop as Meaghan Johnson headed her open boat into the Florida Straits.
Ms. Johnson, a program coordinator for the Nature Conservancy, headed the boat into the swells, to minimize swamping, as her passengers tried in vain to avoid soaking spray.
One of them, Ken Nedimyer, stood next to her at the console, gazing out at the seemingly featureless welter of waves, seeking signs â€” a slight change in water depth here, a barely visible underwater patch of reef there â€” that only he could recognize and triangulate with the rapidly disappearing onshore landmarks of Key Largo.
About two and a half miles out, he told Ms. Johnson to throttle back a bit. â€œOver there,â€ he said, pointing off the starboard bow. â€œAbout 400 yards.â€
The boat pulled up to the site and Philip Kramer, who directs the conservancyâ€™s Caribbean Marine Program, set its anchor. Soon he, Ms. Johnson and Mr. Nedimyer were over the side, peering into the water through their snorkeling masks. Below them was what they had come to see, an array of concrete disks set in the sand. Each one held a tiny piece of coral.
Mr. Nedimyer had led them to a nursery, one of a number he has established since 2000, when chance, coincidence, a government program and a lifelong passion for tropical fish set him on an adventure: a quest to nourish and restore the tattered remains of the Keysâ€™ once glorious reefs.
He is working with assistance from the conservancy, which in turn cooperates with the Florida Keys National Marine Sanctuary and the National Oceanic and Atmospheric Administration, which has its own coral efforts in places like Puerto Rico. Meanwhile, the Environmental Protection Agency is looking at water quality standards for corals in Florida, Hawaii, the Virgin Islands and Puerto Rico, the only American territories where they occur. The Coral Reef Task Force, created in the Clinton administration, regularly assesses coral health. The World Bank, motivated in large part by coralsâ€™ importance for ecosystems and ecotourism, has embarked on a global program to assess restoration efforts and to identify tactics to combat their decline.
And 90 miles south on Highway 1, the traffic-snarled spine of the Keys, biologists at the Mote Marine Laboratory struggle with their own coral nursery efforts. Like Mr. Nedimyer, they are trying to identify strains of coral that grow well in the Keys, and to re-establish them offshore.
Theirs is an uphill battle. Many would say corals globally are already so damaged, and so threatened by further environmental degradation, that there is little chance restoration efforts can turn things around.
Staghorn and elkhorn corals, Mr. Nedimyerâ€™s principal interests, were once abundant in South Florida, the Bahamas and elsewhere in the Caribbean. But since the 1990s they have significantly declined, to the point that last year they were placed on the threatened list, under the Endangered Species Act.
They are suffering the kinds of environmental disruption that afflict corals around the world. â€œWe have lost 25 percent of the worldâ€™s corals in the last 25 years,â€ David E. Vaughan, director of the Center for Coral Reef Research at Mote, said in an interview, adding that 25 percent more are expected to die in the next decade or two. â€œSometimes we sound like doomsday sayers,â€ Dr. Vaughan said, â€œbut those are the facts.â€
Environmental disruption takes many forms. Fishing boats, and even dive boats and divers, can damage reefs. Sea turtles bang into corals, breaking them. Polluted runoff can deprive corals of the clear, oxygen-rich water they need to survive.
And then there is global warming. So far, scientists say, it has had two main effects on coral, both potentially lethal. First, as oceans absorb more carbon dioxide, the chief greenhouse gas, they become more acidic. The acidity makes it more difficult for corals to grow and may even cause them to start to dissolve. And as oceans warm, algae that live in corals, and on which they depend, may be killed.
David Lackland, a biologist at Mote, tells children who visit that corals live with algae as people might live if they liked asparagus, say, but instead of raising it in gardens they grew it inside their bodies, absorbing it directly as energy and fertilizing it with their waste in a symbiotic relationship. Different kinds of corals have different kinds of algae symbionts, but if the algae are threatened, corals are threatened, too.
Another serious disruption is overfishing.
Corals need herbivorous fish to keep unwanted algae under control. When seaweed-eating fish are gone, â€œyou are going to end up with seaweed blooms,â€ said Nancy Knowlton, director of the Center for Marine Biodiversity and Conservation at the Scripps Institution of Oceanography and a leader in the World Bank effort. â€œItâ€™s been shown that seaweeds release a lot of sugars into the water,â€ she said. Because many bacteria need sugars, â€œyou have these bacteria blooms that kill corals.â€
Corals also need predators like groupers, snappers, barracudas and even lobsters to prevent the proliferation of coral-eating snails, worms and other organisms.
Meanwhile, a host of diseases plague coral, many of them poorly understood. For example, staghorn and elkhorn coral are vulnerable to so-called white-band disease, in which coral tissue mysteriously decays. The disease, which struck the Caribbean in the mid-1990s, kills healthy tissue, leaving only white skeletons. It usually progresses quickly, and while it almost never wipes out complete colonies, colonies can be reinfected.
Scientists do not know for sure what causes the condition, and their suspects â€” bacteria, fungi and other microbes â€” are present at healthy corals as well as sickly formations, adding to the mystery.
Corals in South Florida have another big problem, a die-off of sea urchins, which began succumbing wholesale to a mysterious ailment about 20 years ago. Urchins graze on unwanted algae, and without them, corals in many areas have been smothered in overgrowth, making it difficult or impossible for them to grow or propagate.
Mr. Nedimyer focuses most of his efforts on coral, something he got into almost by accident several years ago, through his work as a wholesale dealer in aquarium supplies, a business he has operated for 35 years. One of his products is â€œlive rock,â€ reef rubble that bacteria colonize. In aquariums, the bacteria help break down waste from fish.
He had permission from the government to gather live rock at a particular site and one day about 10 years ago, he noticed that a few bits of rubble had something growing on them. â€œI didnâ€™t know what it was at first,â€ he said. â€œI saw five of these little things. I kept watching them and pretty soon they started to grow out into staghorn coral.â€ He set the rocks aside, underwater, and managed to keep the coral growing in spite of storms and other problems. When he found broken pieces of coral he stuck them in other pieces of rock, and â€œsometimes they would live.â€
In 2000, at an aquarium in Orlando, he heard a presentation on Pacific coral and learned that â€œyou can cut these things into tiny fragments and glue them to things and they will grow.â€ Back in the Keys, he started experimenting. His daughter Kelly helped, turning the work into a 4-H project.
At first it was trial and error. They experimented with growing platforms and especially with how to glue coral fragments to them. â€œWe tried a lot of epoxy,â€ Mr. Nedimyer said. â€œWe found kinds that stick to wetsuits, to hair, to cameras.â€
Eventually, they discovered a two-part epoxy glue used in taxidermy. They can mix it on a boat and it remains workable for about half an hour. And it is white, which looks nice against the sandy bottom.
For a brief heady moment, he recalled, he thought about the fact that he has government permission to sell coral and considered turning it into a lucrative sideline for his business. But then, he said, he started thinking about what had happened to the Keysâ€™ reefs since he first encountered them in the 1970s, â€œwhen there would be thickets three, four, five feet high and just vast.â€
Those kinds of underwater landscapes have just about vanished, he said. â€œSo I thought, well, these corals are in trouble. And we can make a difference rather than make money.â€ Today he has several nurseries, each with a variety of coral strains, at varying depth, water quality and distance from shore. The goal of the project is to identify which coral strains are most robust and in what conditions. Dr. Kramer, Ms. Johnson and Mr. Nedimyer were pleased by the corals they saw at the nursery. After climbing back into the boat, Mr. Nedimyer said: â€œThey were a few inches, now they are two or three times the size. Thatâ€™s a lot of growth in six months.â€
Dr. Knowlton, the coral expert at Scripps, said staghorn coral was among the fastest growing â€” up to four inches or so from branch tips in a year, whereas most corals grow only about half an inch a year. But, she said, corals that grow quickly are often unusually sensitive to their environment. â€œThey can slip from growing really fast to dying really fast,â€ she said.
At Mote, Mr. Lackland maintains and propagates a variety of coral species in tanks, and hopes to emulate Mr. Nedimyer with offshore nurseries between Looe Key and American Shoals.
Like Mr. Nedimyer, Mr. Lackland, who is 40, parlayed a youthful fascination with marine creatures â€” he had corals in tanks in his bedroom as a teenager in Watchung, N.J. â€” into his lifeâ€™s work. After earning a bachelorâ€™s degree in biology, he worked at an aquarium in Point Pleasant Beach, N.J., where his one-bedroom apartment had six tank systems filled with coral. Friends told him he had â€œa blue thumb.â€
Eventually, he said, he decided to go to the Florida Keys, â€œwhere they have the most hurting ocean, an ocean thatâ€™s slipping away as far as its coral cover.â€ He presented himself at the National Marine Sanctuary, where he learned there might be an opening for a biologist at Mote. When he got the job, â€œI was thrilled,â€ he said.
Today, he presides over several rooms full of tanks where many species of coral grow on networks of iron pipes. Mr. Lackland has devised elaborate systems to mimic the flow of ocean currents, the varying pressure of waves and even the coming and going of daylight. He feeds his coral oyster larvae and other plankton, which he buys from an aquarium supplier, and he has devised formulas to maintain the proper mineral balance in the water.
Some of his corals are doing so well they have even spawned in the tanks.
Like Mr. Nedimyer, he is starting corals on concrete disks and establishing them in the water, in his case between Looe Key and American Shoals, near the laboratory.
Dr. Kramer noted that, over all, â€œcorals have managed to deal with many swift changes in the last million and half years.â€ He added, â€œOver these geological time scales, in the long term, corals may be able to handle these climate changes.â€ Meanwhile, though, he said, â€œI think these types of strategies have a real role to play.â€
For scientists like Dr. Knowlton, the major question is not whether some coral strains might do better than others. That is almost a given, she said. â€œThe biggest problem is making a difference on a regional scale or even on a large local scale.â€
She said people interested in corals should focus on â€œfixing the things we can fix â€” climate action or water quality action or stopping overfishing.â€
In interviews, Mr. Lackland and Mr. Nedimyer separately acknowledged that viewed from any reasonable perspective, the problem is huge and their efforts are small.
â€œI am not an ostrich,â€ Mr. Lackland said. â€œThe facts are really bad.â€ But, he added, â€œIf the ocean is really in that bad condition, letâ€™s gear up!â€
Mr. Nedimyer shares this view even though, as he put it, every day he spends on the project â€œis one day I canâ€™t make a living.â€ But one of its major rewards, he said, was its lesson for his daughter Kelly, now 19 and a student at the University of Central Florida, and the Coral Shores students working with him. â€œWe have turned five corals into five to seven hundred,â€ he said. â€œIn another year or two weâ€™ll have several thousand corals. Thatâ€™s mostly one person making a difference.â€