ARNOLD AIR FORCE BASE, Tenn. --
Brian Roebuck is in a tight spot - only his upper body, arms and head sticking out of a narrow, slippery stone passageway. It isn't the first time and it won't be the last.
Minutes later, he's worked himself free and stands in total darkness for a few seconds in a silent world totally devoid of any natural light. Seconds later, his wife Lynn and a friend set off camera flashes to capture a digital image of Brian standing next to a tall column of limestone in a large chamber in Cedar Ridge Crystal Cave near South Pittsburg, Tenn.
An Aerospace Testing Alliance test engineer at the U.S. Air Force's Arnold Engineering Development Center's (AEDC) Hypervelocity Impact Range, Roebucks' interest in caving began 25 years ago, when a coworker casually invited him along for a behind-the-scenes tour of Cumberland Caverns.
What he discovered was another world.
"It was amazing - I couldn't believe it," he recalled. "We went a couple of hours back into the cave and into all these big rooms and saw these formations and things that nobody normally sees - I didn't think anything like that existed around here. I'd been to a few commercial caves, and I had enjoyed those, but this was something else because you got to clamber all over the rocks. It was all wild and untamed."
Much of Tennessee is karstland, a three-dimensional landscape consisting of layers of rock under the soil that are easily hollowed out by ground water through a slow dissolving process. Middle Tennessee's karst is particularly rich in sinkholes and caves.
Over the next few years, Roebuck's interest in caving was strictly recreational. Along the way, he bought an old construction helmet and his first carbide lamp.
"I thought, 'I'm a real caver now," he said, with a laugh. "Of course, I couldn't find any carbide for the lamp. Apparently by that time it had become hard to come by for the average person. It wasn't until a couple of years later when I met some other cavers that I was able to find where I could actually buy the stuff and try it out."
In 1987, he got married to another outdoor enthusiast.
"My wife Lynn and I went on a couple of cave trips - Cumberland Caverns was one of them," he said. But it wasn't until 1991 that they got into caving in a serious way.
"One of my coworkers, Don Lance, on a project in G-Range came in one Monday morning just complaining about how sore and worn out he was from caving all weekend," Roebuck explained. "So, we started talking about it and he kind of got my wife and me into organized caving - and eventually we joined the National Speleological Society."
They started by mapping and surveying caves near their home in Normandy, Tenn.
Using a compass, inclinometer and survey tape, precise measurements are made to make an accurate map of a cave to determine the relationship of the cavern to surface landforms, other cave passages or other caves. Cave passage outlines and features are sketched showing the survey point locations. Together these data are used to create cave maps.
Before long, the couple found themselves drawn deeper into virtually every aspect of caving, including the biology, geology, archaeology and historical significance of caves.
While exploring a cave in Bedford County prior to a mapping and survey project,
Roebuck and his fellow cavers discovered a sizable colony of bats. It turned out to be a large maternity colony of federally endangered Gray bats, a significant find that was later well documented by AEDC Conservation Biologist John Lamb and scientists with the Tennessee Division of Natural Heritage.
"These were some pretty large bats, larger than the small ones we usually saw," Roebuck said. "Once we verified what kind they were, it ended our survey trips into the cave for the rest of the summer because they were raising their young. We had to stay out of the cave until they left in the winter.
"John Lamb and the others came out there to tag some of the bats," Roebuck said. "We helped them catch some of the bats - we used a mist net. Then they tagged them and later used a tracking device to locate them. They actually found some of those same bats in Mammoth Cave, Ky. In the winter time - that's where they hibernate."
Along the way, Roebuck and his wife met and made friends with a number of interesting people, including Dr. Thomas Barr, a zoologist who wrote a book called 'The Caves of Tennessee.'
"My wife and I started collecting these tiny cave beetles for Dr. Barr who is an expert on these insects," he said.
Cave beetles are rare insects typically 3 to 7 millimeters long that live exclusively in caves, some species so rare they are found in only one or two caves in the world.
Roebuck said caves are living, fragile ecosystems that need protection, whether from vandalism or unintentional pollution and destruction. Home to rare and endangered species, the caves are also windows into the past.
"We found caves where the walls were covered with spray-painted graffiti," he said. "But underneath it was Civil War-era graffiti and beneath that was charcoal - possibly prehistoric drawings and symbols."
He and his wife have also helped other volunteers clean hundreds; even thousands of pounds of trash - old appliances, car parts and tires - from caves, sinkholes and watersheds leading to cave systems.
"In the karst areas of Tennessee, water quickly travels underground without being cleaned or filtered as it joins the ground water already there," he explained. "Polluted water introduced into karst features such as caves or sinkholes generally spreads far and wide in the ground water.
"As cavers we try to keep the location of some caves secret or make sure they're gated to protect the formations, endangered wildlife and historical aspects. Developers who build homes or businesses over cave networks aren't being responsible - this can introduce serious contaminants into the groundwater and carry it for miles."
He distances himself from taking environmentalism to extremes, but jokes that "you've heard of tree huggers, well, I'm a limestone hugger."
A few years ago, he and his wife traveled to France on a trip that led to something they never dreamed possible - a behind-the-scenes tour of Lascaux, the famous cave in France known for its prehistoric art. They were working with University of Tennessee- Knoxville and French archaeologists and students on excavating a cave in the Dordogne region of France when the French archaeologist invited them to see the famous cave.
"The paintings were just amazing," Roebuck recalled. "They almost seemed to move - they were more like a mural - the paintings formed a theme."
The trip to France was a high point in a life he considers rich in discovery and unforgettable experiences, but Roebuck still finds plenty of adventure at home.
"There are over 9,000 known caves in Tennessee," he said. "I've probably been in about 500. There is still so much to see - to experience and learn."