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Public Radio's Environmental News Magazine (follow us on Google News)

Hot Springs Microphiles

Air Date: Week of

Producer Sam Hendren and science journalism professor Michael Ray Taylor go on an expedition to Hot Springs National Park in Arkansas. There they discover a frontier of unknown life forms.


CURWOOD: It's Living on Earth. I'm Steve Curwood. During this summer season of travel and exploration, tourists flock to Hot Springs National Park in Arkansas to enjoy the waters. They may not know it, but they're also coming to a frontier chock full of unknown life forms. Producer Sam Hendren went on an expedition there with the help of science journalism professor Michael Ray Taylor.

(Bird songs, voices calling)

HENDREN: It's 10:30 in the morning on a bright summer day in the resort city of Hot Springs. Tourists stroll along the historic Grand Promenade, cooled by breezes that carry the fragrance of magnolia blossoms. But we're about to leave all that behind for a trek into the dark, damp underground with veteran cave explorer Michael Ray Taylor. He's putting on a caving helmet knotted a head lamp at the opening to a tunnel.

(Flowing water)

TAYLOR: This is a man-made structure. It's not a cave, but as we go through you'll see it's very cave-like. Most of the tunnel was built of local rock in 1880.

HENDREN: That rock is smoothly cemented into place in the walls and ceiling. The floor is actually a fast-running rocky stream, which according to Taylor won't get much deeper than our knees. The magnolia fragrance is gone, replaced by a faint sewer odor. Taylor convinces me that any seismic activity along the New Madrid Fault 100 miles to the northeast couldn't possibly reach Hot Springs. But he isn't as reassuring about water moccasins and tarantulas.

TAYLOR: Oh yeah, we got them. But they won't bother you.

HENDREN: This tunnel was built to counter flash flooding and to channel the Hot Springs runoff, which was turning the lawns of the proliferating 19th century bath houses into swamps. A hundred years ago Hot Springs was America's health spa. People came from around the country to bathe in the thermal waters here, which they believed were therapeutic. Taylor and I are about to do another kind of bathing.

(Splashes through water)

TAYLOR: As we hike down and enter the part of the valley where the hot springs emerge, you'll notice a fog beginning to descend in the tunnel. It will start feeling steamy like a sauna, and that means we're getting close.

HENDREN: Close to the hot springs that gush from beneath the earth at 146 degrees Fahrenheit. Eight hundred fifty thousand gallons pour forth every day, more than was enough to meet the demands of the elegant bath houses even at the height of their popularity. Today, visitors are more interested in drinking the water. Many carry it away by the gallon. Rather than taking us to one of the many steaming public fountains, Taylor is taking us straight to the source.

(Echoing voices amidst steam)

HENDREN: You feel at home down here?

TAYLOR: Oh, yeah. Hey, while we're stopped here, look ahead. You can see a level in the air that there's steam down below about four feet or so, but it's clear at the top. And that steam should begin to rise as we walk further down toward the bath houses.


HENDREN: This mile-long trek might have been nothing more than a hike through a city sewer system if it weren't for the fact that Taylor is a rare participant in frontier science. In spite of his love for the occasional underground echo --

(Taylor's echoing maniacal laugh)

HENDREN: -- and an even more poorly-timed question --

TAYLOR: You don't suffer from claustrophobia, do you?

HENDREN: -- Taylor is working with NASA in an investigation of newly-discovered microscopic forms of life. His interest was sparked in 1996 when he accompanied a scientific team into the cave Lechugiuilla in New Mexico. That cave is tightly sealed from all familiar forms of life, without so much as a bat or a blind fish. But it was there, he explained, that he was awakened to another world.

TAYLOR: What I discovered on that trip was that I had been missing the fact that in Lechugiuilla and many other caves I had been going through an inhabited world. It turns out the cave's life is microbial. And there was a whole universe, a whole Amazon rain forest full of microbes that were existing off the chemicals in the rocks. And the more I looked into it, the more I realized that there was a major shift going on in biology.

HENDREN: A paradigm shift, according to Taylor, who says these newly-discovered microbes are completely independent from the food chain humans belong to. A chain sustained by sunlight and photosynthesis.

TAYLOR: One of the most interesting things about this other food chain is you don't really need a nice, comfy, good-distance-from-the-sun planet like earth to support it. In fact, there are several planets in our solar system where this sort of chemical-based food chain could be quite happy, down in the caves of Mars, down below the icy moons of Jupiter.

HENDREN: Even in the perpetually steaming waters below Hot Springs Mountain, which is why these organisms are sometimes called extremophiles - because they live in extreme conditions. They sustain themselves, Taylor speculates, by ingesting minerals in the rock. But it wasn't until Taylor sent samples of the Hot Springs mineral travertine to the Johnson Space Center in Houston that the presence of microbes was confirmed.

TAYLOR: We got them down to NASA and put them on the very fine electron microscope that they have there. And sure enough, these mineral deposits were loaded with bugs, all kinds of bugs.

HENDREN: Previously unidentified microbes had been found in other hot springs, for instance, in Mammoth Hot Springs in Yellowstone National Park. What surprised NASA was the seeming resemblance between the Arkansas microbes and those reportedly found in the famous Martian meteorite that made headlines around the world in 1996.

(Steaming water)

TAYLOR: We're getting closer! (Voice lost in echo)

HENDREN: After an hour maneuvering the slippery stream bed, we reach two hot springs that are side by side. The waters that pour forth have taken millennia to make the journey here, falling as rainwater 6,000 years ago, traveling a mile or so underground where it's heated, and then rising through the earth to arrive here in the tunnel. As the strong beams of our lamps cut through the steam, it's hard to believe that living things survive in these waters.

TAYLOR: Well, it's hot to us, but it's not hot to them. We're hot standing a few feet away from this. If you put your hand in that water, you'd have a third-degree burn in a very short period of time. But to the bacteria it's home. Nature has found a way to protect them, and that's what makes this world so alien and so interesting to explore.

HENDREN: Beneath the spray of the two springs are two beautiful travertine deposits. The one of the left is a deep bluish-black outlined in orange. The one on the right is a dull tan. Taylor says the differences are due to different mineral compositions, slightly different water temperatures, and, he believes, different organisms in the two springs. At the point where the deposits come together, there is a darkened band.

TAYLOR: To a microbiologist, what this darker band would represent is a war zone. And these Hot Spring bacteria are competing for that area where they come together, and in competition what microbes do is produce poisonous chemicals to throw at each other. And of course, drug researchers and others, industrial researchers, who use microbial products, would be very interested in this little war zone, because that's where you're likely to find unusual chemicals being produced, that, if you could figure out how to manufacture them, might represent a new class of antibiotics or might represent a new material to take the paint off of ships.

HENDREN: Because of that, Hot Springs, Arkansas might well be the next field of exploration for bio-prospectors. And because of Taylor's findings, the Park Service has had to delete its reference to the "sterile waters" from its visitor's guide.

TAYLOR: I can catch some in my hand. It's got a very sweet taste, like mountain spring water. You've just got to watch out not to burn your tongue as you drink it. Delicious.

HENDREN: Hot Springs water is extremely popular. In fact, some people drink nothing else. They drive hundreds of miles to collect hundreds of gallons in a single trip.

(Traffic; honking)

HENDREN: On a street corner above, not far from our position in the tunnel, Kathryn Purpur and her husband are filling gallon jug after gallon jug.

(Pouring water)

PURPUR: This is wonderful. Ever since we were coming here, we would gather the water because it tastes so good. Never heavy on your tummy. (Laughs)

HENDREN: Mike Taylor suggests the Hot Springs microbes might even be user-friendly. Kathryn Purpur didn't know about the microbes, but she says Hot Springs water has been helpful for her husband.

PURPUR: I think this is cleansing and of value. My husband has Parkinson's, and to look at him, he's had it for 26 years. And I think that it helps.

(Flowing water)

HENDREN: With the prospect of a grueling hike back through the pitch black tunnel, Taylor suggests using one of the emergency escape routes that have been added in recent years. Climbing up plastic rungs, we press through a manhole cover and emerge, once again, into bright sunlight.

(Manhole cover clangs)

TAYLOR: (Sighs) Daylight! Hoo! Boy, it's hot down there. Aah, fresh air.

HENDREN: The journey has been a brief one, but we've traversed an entire universe where these extremophiles are concerned. Michael Ray Taylor says those entities may lead to unimagined medical treatments in the future. They may even help unlock the mysteries of life on earth, and beyond. For Living on Earth, I'm Samuel Hendren in Hot Springs, Arkansas.



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