TAVERNIER, Fla. — About a mile offshore, with only a light west wind, and a blistering sun, the heat of day came on fast, as if to convince the marine researchers to hurry and get in the water.
First overboard, in a full wetsuit and strapped to an old gray scuba-tank, was Ken Nedimyer, who makes his living collecting tropical fish and growing aquarium live-rock, which he sells on the Internet.
On this trip, though, he is chasing his passion, which is much bigger than his job, if not nearly as lucrative. Nedimyer is determined to help save the dying reefs of the Florida Keys, and has given it years of his own free time.
"It makes you feel good," he said. "Making a difference, and making a positive contribution is worth more than a lot of money."
One man's concern
Since childhood, Nedimyer has been diving the colorful reefs off the Florida Keys. Over the years, he became increasingly upset by what he was witnessing — a dramatic decline in the size and number of living underwater coral structures.
"I used to see these corals everywhere, huge thickets that covered acres," he said. "And now I go to some of those patch reefs, and there's just one little spindly colony left."
Scientists say it's a serious problem affecting marine ecosystems around the world.
At the Mote Tropical Research Lab on Summerland Key, Florida, Executive Director Dave Vaughn said that in the last three decades, 25 percent of the world's corals have been lost, primarily because of rising sea temperatures and increased carbon dioxide levels caused by global warming.
The problem, he says, is accelerating at an alarming rate. "In the 50 years of our generation we may lose half the world's corals on our watch."
An inspiring 4-H project
For Nedimyer, a potential solution for some of the problem revealed itself five years ago, when he noticed that tiny staghorn corals were beginning to grow on his underwater aquarium rock collection. It was an interesting discovery, because the elegant staghorns had virtually disappeared in the Keys.
At first, Nedimyer saw this as an economic windfall for his aquarium-supply business. "I thought this is neat. I was initially thinking of it as a way to make more money."
But, after thinking about it some more, and with prodding from his then 14-year-old daughter, Kelly, Nedimyer realized there was a more urgent need elsewhere.
"Kelly and I started thinking, you know, there's just a whole lot better use for that coral right down here in the Keys, and so we haven't sold any of it on the commercial market."
Instead, their first venture was to make it the focus of Kelly's 4-H project. "4-H, you think of growing pigs, cows and chickens," Nedimyer laughs. "We said, we'll grow coral."
From that small beginning, a plan for planting underwater staghorn coral nurseries was devised, and requisite licenses were obtained. The ultimate goal was to replenish a few dying reefs.
Nedimyer and his daughter experimented with different kinds a glue, and by messy trial and error finally figured out how to attach tiny staghorn tips to rock platforms stretched out over the ocean floor.
Because staghorns can grow very quickly — double or triple in size every year — the first five small colonies have now grown to hundreds of much larger staghorn groups nestled in the waters off Tavernier Key. Some of them were planted in an area of Molasses Reef where in 1984 the freighter Wellwood ran hard aground and cut a swath through the delicate coral beds.
Finishing up a recent scuba dive, and grabbing for the ladder of his boat, Nedimyer was asked how everything looked down below on his underwater coral farms.
"They look great," he boasted. "The corals are beautiful, some of them have really grown a lot.
His biggest hope is that others will follow his lead, because he believes coral replanting can work almost anywhere.
"I think it can be replicated up and down the Keys, and really throughout the Caribbean."
Nedimyer is coordinating his efforts with The Nature Conservancy and Florida's Mote Marine Laboratory, where scientists are also studying the effectiveness of coral planting.
In a small, windowless room filled with brightly colored saltwater tanks, marine biologist David Lackland pays close attention to the many different species of corals he is growing. "I'm a proud daddy when I look at that kind of stuff," he jokes.
Lackland is most passionate about coral and its future, and worries about its decline around the world.
"The coral reefs are such a biological hot spot that if we lose those, the food chain above, everything in the ocean is going to suffer," he said.
Speaking of the staghorn and elkhorn corals that used to fill the South Florida reefs, he adds, "It's sort of depressing how fast these animals are going. And for as quick as they grow, it seems like they are disappearing just as fast."
Studying heat-resistant coral
Scientists say planting coral in the ocean can be tricky, because of changing environmental conditions. With rising ocean temperatures currently considered the primary cause for coral bleaching and die-offs, researchers are now studying heat-resistant coral.
"With the water quality and temperature and conditions continually getting worse, it may be harder and harder to replant the same coral that survives today," said Vaughn, at the Mote Lab.
Experts are also trying to understand why some corals of the same species, in the same colony, appear to weather rising temperatures and resist diseases better than others.
Meaghan Johnson, a marine program coordinator for The Nature Conservancy, has been diving with Nedimyer, trying to help unlock the secrets of coral survivability. She spends much of her time with a project known as The Florida Reef Resilience Program.
"It we can do our part here, and try to understand why some of these corals are doing better than others and really focus on those, I think we're ahead of the game," she said.
Nedimyer and other scientists are also taking note of the role spiny sea urchins may play in cleaning and protecting coral reef species.
The small, black sea creatures with long, sharp spines were very common in Florida Keys waters thirty years ago, but then virtually disappeared in the 1980's, because of a disease. Now they are starting to come back, and researchers have noticed they seem to promote the health and growth of corals by eating away algae and seaweed. As scientists contemplate coral planting programs, they are also considering the need to replant sea urchins with them.
"This is all very new," said Johnson. "It's all happening very quickly, and it's things we need to adapt to and try to figure out."
Finishing up another day of photographing and measuring his underwater coral nurseries, Nedimyer agreed with the need for more scientific studies.
"Growing coral is one thing," he said. "Finding the cause of the coral dying is another thing. You have to do both."
To fund some of this research, the State of Florida is now offering a special automobile license plate. Beneath a colorful image of coral, tropical fish and a scuba diver, the message on the plate is simple and to the point — "Protect our Reefs."
© 2013 NBCNews.com Reprints