Dangling from a rope down a deep pit of acid, hot water and poison gas might not be most people’s idea of a good time-but there’s nowhere else caver Michael Ray Taylor would rather be. And for Taylor, the point is not just going where no one has been before. The samples he brings back contain tiny creatures, many new to science, that thrive in extreme conditions. Dark Life is his account of travels in the belly of the Earth. Maggie McDonald spoke to the man who goes where microbiologists fear to tread.
What does the “dark life” in the title of your book refer to?
Dark life is my catch-all term for subterranean extremophiles, microbes that can survive in extreme conditions of heat, pressure, cold, salinity and acidity that would kill off most other microbes. You’ll find such conditions in Mexico’s Cueva de Villa Luz-literally house of lights-a cave festooned with hanging webs of microbes, or snottites. The microbes are part of a food chain for a variety of insects, arachnids, small fish, etc. The only other place I know of with such a bizarre, large food chain is a cave called Mobile in Romania. It’s extraordinary to find an ecosystem like that in a cave full of poisonous gas and dripping with acid. I find this fascinating, because it partly explains how the cave formed. The microbes secrete acid that hollows out new passages.
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What’s the point of going down a cave?
I think everyone likes the idea of setting foot where no one has been before. But cavers can also help scientists by gathering samples.
Don’t scientists like getting their hands dirty then?
Many microbiologists who study extremophiles in the lab cannot stand the idea of crawling through tunnels and using ropes to get in and out of pits. I often send samples to people. Or if I hear about a new discovery in the world of caves, I’ll put a caver in touch with the right specialist. I did this recently with cave divers in Yucatán in Mexico who did a breathtakingly dangerous dive in a freshwater spring that emerges beneath the Gulf of Mexico. They found rooms full of sulphur mats of extremophiles off passageways at a boundary of freshwater and saltwater. I got in touch with the lead explorer. He sampled this stuff and sent it to researchers in New Mexico and at NASA. They think the microbes might be nanobacteria.
Have you ever thought of taking up research yourself?
I don’t have a hard science background. I’ve come back to science after being a writer and an arts major in my youth. If I didn’t have a mortgage and three small children, I might enrol in graduate school, then spend a few years getting a doctorate in microbiology. But I can still make a meaningful contribution to the field of extremophiles. I feel just like one of the amateur archaeologists who discovered the many unexcavated tombs in the Valley of the Kings in 1875.
How did you begin caving?
It all began when I was a student at Florida State University in Tallahassee, in the late 1970s. Most people think Florida is too flat to offer much in the way of geology. But in the western part, there are many small limestone caves. I started poking into those and found this fascinating hidden world I never knew existed. Florida also has many underwater caves. In fact, it’s a world capital for underwater cave exploration. I can’t gallivant off into wild, unexplored caves as much as I used to, but I still try to get on a small expedition that’s mapping new caves at least once or twice a year. This is the big attraction, finding a new area you can carve out for yourself.
Caving clearly isn’t for the faint-hearted. How dangerous can it get?
Safety is taken very seriously. I’ve done some exploring down lava tubes in Hawaii. The caves seemed pretty dangerous, but I don’t think I was putting myself in harm’s way. I think we got about as close as one could get to being inside an active volcano without suddenly finding a river of lava flowing towards you.
Can you ever see a cave actually forming?
Yes. But there’s quite a lot of debate between cave geologists over exactly how caves form. The issue is whether the chemical reactions that produce acid-which forms cave passages-are biological, or geological. In the Villa Luz in Mexico, we know they’re biological. We think that the microbes produce the acid. You can look at the floor and see holes that the individual microbes have created.
You refer in your book to a chamber in a cave that’s called the “Chandelier Ballroom”. Where does it get its name?
The Chandelier Ballroom is in the Lechuguilla caves in the Carlsbad Caverns National Park in New Mexico. It gets its name from the pure white stalactite crystals up to six metres long. I’d been caving for a decade before I saw it and had never seen anything like it. It’s breathtaking. The system’s about 170 kilometres long and still growing from its single entrance. Originally, I went there just for the sheer joy of discovery, but in the early 1990s everyone began to realise that there was something unique about the microbes. The fact it has so many unusual mineral formations might be related to the many unusual microbes living and feeding in its walls. No one actually knows where they get their food from. Clearly not from the outside, because there’s been no influx of organic materials from the surface for millions of years.
Microbes can’t survive without some source of energy. Where do you think this comes from?
The theory is that that all cave bacteria indirectly feed off guano deposits, the excrement brought in by bats and cave birds. Bats fly in and out of the caves all the time. They tend to feed outside, dumping guano on the floor of caves when they return. That becomes the base of the microbial food chain. And for a long time, cave biologists believed they had no other source of food.
In open caves, rainwater brings in dead leaves and other debris, but the Lechuguilla is a sealed system. If you have beetles crawling in a pile of bat guano, they’re indirectly living off photosynthesis, but if you have a group of microbes in a sulphur-rich cave, they may not be using the sulphur themselves, but somewhere at the base of their food chain minerals are being used as an energy source.
Are you likely to find any microbial life that’s new to science in a cave open to the public?
You’re unlikely to find anything of worth in a cave such as the Carlsbad Caverns, which is open to visitors. This is because the environment has been so radically altered by a million tourists walking through. You could never take a sample from anywhere in the chamber called the Big Room at Carlsbad Caverns and know whether the microbe you found was indigenous to the cave or indigenous to New Zealand, carried in on the feet of a tourist.
Your book is bound to attract more people to caving, which could be good for science. But is it good for the caves themselves?
Anyone who is involved in caving becomes part of the eternal struggle between secrecy and publicity. It’s a delicate balance. Cavers are conservation-minded because it’s so easy to destroy that which we love by overuse. Yet if secrecy were absolute, then there would be no public protection for caves, and no understanding of why they’re significant. Some caves must always remain open to the public. Where caves cannot sustain large numbers of visitors, some must be closed. Think of the delicate, prehistoric cave paintings at Lascaux in France-they would fall off the walls if visitors were allowed to visit them daily. Instead, the cave and its paintings have been recreated in a visitor centre.
What do you recommend for first-time cavers? Should they join a caving club, or can they go it alone?
You need to join a caving club. There are caving clubs throughout Europe and the US. I recently gave a talk on dark life to high school students. One of them said he wanted to go into caving and also wanted to study biology at college. I put him in touch with a caving club. Within a month he had found a microbiologist willing to work with him through that cave club, which was collecting samples in wild caves. Someone took the student to a cave that had seen perhaps 20 visitors since its discovery a few years ago. He gathered samples for the scientist, who found new species of microbes. With determination, almost anyone can do it.
What are you doing next?
I’m continuing research at Hot Springs National Park in Arkansas on the role of bacteria in travertine formation. I hope to return to Mexico later this year. There are rumours of a sulphur pit in a mountain above the Villa Luz. No one’s ever been into it but it’s more than 30 metres deep. The only problem is that it takes a three-day jungle trek to get there and it would need to be explored slowly and carefully. In fact the groups may simply lower a video camera and record whatever is in the first room and later work out a plan for exploring it.
I also hope to take part in plans by NASA’s Jet Propulsion Lab to take a robot craft to Lake Vostok, the lake beneath the polar ice cap in Antarctica. I hope to go down as a journalist. The group at JPL are developing a device called the Hydrobot, which will penetrate and collect samples from Lake Vostok without contaminating it. It will serve as a model for future space craft exploring Jupiter’s moon, Europa.