Michael Garman and his dive mates can travel back thousands of years in about a half hour.
The underwater journey is not an easy one. The divers battle strong ocean currents and the flow from a freshwater spring to reach their prehistoric destination.
They must wriggle through limestone openings so small they cannot wear their air tanks. Instead, they push the tanks ahead of them.
They rely on training, experience and thousands of dollars worth of equipment to keep them alive in an underwater cave system that opens just off Crystal Beach.
Once the divers have wormed their way into a spacious cavern and donned their gear _ a 30-minute trip _ the cave honors their efforts with a seemingly endless display of spectacular sights.
"We found some really neat stuff _ little side rooms off the main tunnel with orange fungal carpets, stalactites hanging from the ceiling, and there are beautiful iron formations," says Garman, a Dunedin resident. "It's just full of surprises, really dynamic. This cave is really visually stunning."
When Garman and three other Tampa Bay divers began exploring the Crystal Beach Spring cave system three years ago, they became the first divers ever to lay eyes on the prehistoric community.
The spring's presence was no secret: Visitors to Crystal Beach can stand on land and spot the "boil" just off the coast where the freshwater bubbles to the surface of the saltwater.
But the opening of the spring, about 20 feet down at high tide, was so small that most divers did not dare go in.
If the tight squeeze did not keep thrill-seekers out, local lore did. Some say a diver drowned near the mouth of the spring years ago, prompting the Coast Guard or the Army Corps of Engineers to cover the spring's opening with boulders. That rumor is unsubstantiated.
As a teenager growing up in Largo, Pete Jubb explored the mouth of Crystal Beach Spring. Now a cave-diving instructor, Jubb showed the area to diving friend Brett Hemphill in 1995.
Hemphill, a Tampa resident, teamed up with Garman, Garman's wife, Sherry, and Lutz resident Rudy Sturm to see if the site was diveable.
Three years of effort and curiosity have taken the team about 4,000 feet back into the cave, under Lake Chautauqua and Crystal Beach neighborhoods. The deepest rooms of the cave drop down 130 feet so far.
"It was tremendously exciting, when we got going, to find a cave like this," said Sturm. "It's like a mountain climber finding a new mountain no one ever knew about.
It's rare in this age, especially in this area where everything's been scoured over."
"We come out and say, "We cheated life again." '
Exciting or not, exploring this underwater cave was not a decision made lightly.
Divers must pass through three tiny openings, the stuff of a claustrophobe's nightmares, to get to an area big enough to put an air tank on. Not even a ray of sunlight pierces the cave's bowels, which are lit only with flashlights.
Since no one had ever been inside the cave, no guideline or map existed. The divers have reeled a braided nylon line through the cave, knotting it every 10 feet and tying it off on rocks or stakes whenever the cave changes direction.
When silt in the water is kicked up by the divers or the incoming tide, visibility is reduced. Divers then can use the line to find their way out.
The divers communicate with lights and hand signals.
"You always have to be on your toes, aware of your environment and what's going on around you to make sure you're safe," said Sherry Garman. "Your whole life can depend on your ability to find your way out.
"Just being able to go way far back in a cave and you can do it and survive is neat," she said. "Sometimes we come out and say, "We cheated death again.' "
The divers use computer models to figure out how much oxygen and nitrogen to put in their air tanks. The mixture depends on how deep the divers are going and how long they will be under water, which is usually about three hours.
A mistake can cause a diver to have a seizure, which can be a death sentence.
"It's like doing a regular sky dive, and then there's the guys that do the intricate formations _ it's a whole other level of the sport," said Sturm, who has been cave diving seriously for 10 years. "It's taken me years to work up to this point."
The group has experienced minor mishaps like failing lights. One diver who was visiting the cave with the other four broke the regulator off his tank and had to share air with another diver.
For all of the divers, the expedition is a hobby. Michael Garman is an environmental engineer; Sherry Garman is a staff assistant at the Clearwater Police Department who runs a photo album design business. Sturm is a registered psychiatric nurse; Hemphill owns a window-cleaning company.
When they're not at the office, they're exploring the cave, snapping pictures, shooting video, keeping track of animals discovered, taking water samples and recording depth readings.
"They have done an amazing job on this one," says Bruce Ryan, administrative manager for the National Speleological Society Cave Diving Section. "These folks have done all the right things as far as tying together all the components, as far as the science, taking water samples, finding different species, taking video, doing maps, doing all the technical aspects. They're fantastic."
The divers, who formed a company called Hydro-Geo Environmental Research Inc., are supported by occasional grants from the National Association for Cave Diving in Gainesville, and by the generosity of dive shops and equipment makers who provide discounts or free products to test.
Each diver has about $10,000 invested in tanks. The group's dive lights and cameras cost about $20,000, Michael Garman said. Each diver uses about $30 to $40 worth of oxygen on a dive.
"It's pretty much a hobby," Garman said. "Maybe we'll get some deal with National Geographic. That's everybody's dream. Until then, you've got to have a real job."
Their work has generated interest beyond Tampa Bay. The divers escorted a camera crew from PBS into the cave not long ago for a piece about Florida springs.
The end of the show, which will air late this year or early in 1999, is dedicated to the Crystal Beach Spring cave system, said Sturm.
"To have this great thing uncharted right here in our back yard, it's really been a wonder for me," Sturm said. "Right smack off the highway in an urban area we have this cave, and the water's so clean, it's amazing."
"A sense of belonging, a sense of responsibility'
Caves like the one connected to Crystal Beach Spring take at least hundreds of thousands and sometimes millions of years to develop, says Mark Stewart, a geology pro fessor at the University of South Florida.
Slightly acidic rain and groundwater eats through the limestone, turning tiny cracks into large caverns.
About 5,000 years ago, the Crystal Beach cave would have been above sea level. It could have been used by American Indians or other early inhabitants as a home, he said.
A similar expedition into Wakulla Springs in the panhandle turned up American Indian artifacts several hundred feet below the water, he said.
The divers have not found any signs of human life in the Crystal Beach Spring cave. But the marine life has been fascinating: snails the size of pin heads, orange "jellyballs" of bacteria and possibly a new species of albino crawfish.
The entrance to the cave plays host to freshwater and saltwater animals.
"You get a mixed community," Garman said. "They're all hanging out together."
Garman has enlisted the help of scientists as close as the Florida Museum of Natural History in Gainesville and as far away as the Royal Ontario Museum in Canada to identify the organisms found in the cave.
One of the most fascinating discoveries is in a room the divers named the Dragon's Lair, 2,400 feet into the cave system. A razor-thin line separates a layer of saltwater on the bottom of the cavern from freshwater at the top.
Where the two layers meet, a freshwater bacteria feeds off the sulfides in the saltwater, producing a chemical reaction that looks like smoke.
"It's just spectacular, the swirls and eddies in it," said Michael Garman. "It makes you want to sit there and watch it."
Some of these chemical reactions may prove useful to humans, Garman said. That is why the divers are studying the underwater environment so closely.
A flowing spring with such an extensive cave system is rare in Florida, said Ryan of the National Speleological Society Cave Diving Section. The pressure that makes springs pump water from the aquifer has been reduced by development, agricultural practices and diversion tactics, drying many springs up, he said.
Springs in north Florida are less affected because there is less development, he said. It is also easier to find springs there because the limestone is closer to the surface.
"These things used to be everywhere. Now there's fewer and the farther south you go, the harder they are to find," he said. "To even find anything pumping out in the gulf is a challenge."
The four local divers say they will continue to explore the Crystal Beach Spring cave system until it dead ends or becomes too small to swim through.
They plan to chart every nook and cranny of the cave, naming each section as they go: In Thunder Road at the beginning of the cave, divers can hear the motors of boats and other watercraft whirring above them. The R & B Room is named for Rudy Sturm and Brett Hemphill, who discovered it.
"I think of it as our cave, my cave, because we're the first to explore it. We know every inch of it," Sturm said. "When you do something for the first time and you're the first person to do it, there's just such a sense of belonging, a sense of responsibility for it. It just has a special place in your heart."