Cover image for Dark life : Martian nanobacteria, rock-eating cave bugs, and other extreme organisms of inner Earth and outer space
Dark life : Martian nanobacteria, rock-eating cave bugs, and other extreme organisms of inner Earth and outer space
Taylor, Michael Ray, 1959-
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Publication Information:
New York : Scribner, [1999]

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287 pages ; 22 cm
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QR100.9 .T38 1999 Adult Non-Fiction Non-Fiction Area
QR100.9 .T38 1999 Adult Non-Fiction Central Closed Stacks

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In a narrative that combines cutting-edge science with intense physical adventure, "Dark Life" tells the fascinating story of the quest to find life far underground and deep in space.

Able to thrive without sunlight or oxygen, dark life is a mass of subterranean bacteria that would likely tip the scale if weighed against all other living matter combined. Journalist Michael Ray Taylor takes us from Antarctic lakes to Hawaiian volcanoes to the satellites of Jupiter in search of these mysterious underground creatures that are redefining our understanding of evolution.

Taylor serves as a field assistant on several key scientific expeditions. He descends deep into New Mexico's tortuous Lechuguilla Cave and focuses powerful NASA microscopes on never-before-seen life-forms. He accompanies a young NASA intern who unknowingly kicks off a raging international scientific debate when she uncovers traces of dark life in a rock extracted from nearly two miles below Washington State -- traces that appear identical to the "micro-fossils" found in a Martian meteorite. He meets another scientist who has staked his reputation on using dark life

Reviews 4

Booklist Review

Extremophilic life so challenges notions of life's requirements that it has started the latest gold rush in popular science writing: Taylor's work follows Life on the Edge by Michael Gross and The Fifth Miracle by Paul Davies . Gross and Davies are certified scientists; Taylor is an amateur science enthusiast--so enthusiastic he talked himself into some science teams descending deep into caves to collect microbes. When not acting a Plimptonian part, Taylor detaches himself to describe big recent discoveries, such as a submarine volcanic eruption that spewed out millions of tons of microbes or a Lake Ontario-sized lake beneath the Antarctic ice cap whose environment could be a test run for searching for life on Europa. Absorbed by the subject, Taylor dwells longest on the research behind the most famous extremophiles to date, the possibly fossilized microbes found in that Martian rock. A lively account with the encouraging subtext that some areas of science can still welcome participation by the nondegreed. (Reviewed March 15, 1999)0684841916Gilbert Taylor

Publisher's Weekly Review

The dark life of the title is made up of the masses of bacteria that live deep within the bowels of earth. Taylor (Cave Passages), a veteran caver and professor of communication and theater arts at Henderson State University in Arkansas, explains that these tiny organisms are so abundant that collectively they are thought to weigh more than all the aboveground biomass. Species as yet undiscovered by scientists are thought to abound and to be likely to shed insight into the origin of life. While of interest, none of this is particularly controversial. What is hotly debated is the size of the smallest of these life forms. Taylor argues in favor of the existence of nanobacteria, life so small that many scientists refuse to believe they are possible, contending instead that the patterns observed are due to chemical rather than biological processes. The debate is crucial because the fossils attributed to a rock from Mars are of this sortÄif nanobacteria don't exist, traces of life have not been found on the red planet. Mixing science and adventure writing, Taylor describes fact-finding and collecting expeditions into uncharted caves. While he does a commendable job of vivifying the beauty of these strange environments and the passions of the scientists who study them, he is much less evenhanded when discussing the scientific controversy swirling around the nanobacteria themselves. Agent, Esther Newberg. (Apr.) (c) Copyright PWxyz, LLC. All rights reserved

Library Journal Review

Taylor, an experienced caver and author of Cave Passages (LJ 5/1/96), demonstrates a knowledge and respect for this environment as he presents the ten-year odyssey that introduced him to the biology of extreme environments: caves, deep drills into the earth, volcanoes, even the surface of Mars. Taylor focuses primarily on caves, but the parallels with possible life in extreme and extraterrestrial environments are interesting. Taylor maintains that the microbes found deep in the earth are a form of life, a "dark life" that possibly demonstrates the very origin of life, but he includes the opposite view and the option that there just isn't enough information yet for proof. His prose style is easy to read and episodic, like a series of articles. Taylor is not a biologist, but he makes the biology understandable. He includes both suggested readings and web sites for further information. Recommended for larger public libraries or specialized natural history collections.ÄJean E. Crampon, Science & Engineering Lib., Univ. of Southern California, Los Angeles (c) Copyright 2010. Library Journals LLC, a wholly owned subsidiary of Media Source, Inc. No redistribution permitted.

School Library Journal Review

YA-Taylor first heard of "dark life" from scientists searching for it in the pristine environment of a newly discovered cave system. Nanobacteria had been unknown until very recently, when advances in electron microscopy finally revealed them to astonished human eyes; now, many of the hidden places of the earth, previously thought to be "sterile," were seen to be teeming with strange and diverse creatures. Taylor crossed the line from journalist-observer to participant-advocate, joining the quest for these new "bugs" and the secrets they might reveal about the nature of life. The story is compelling not just for the fascinating nature of the discoveries made, but also for the insider's view it offers of science as a working community. One likable young scientist, Anne Taunton, stands out among the many colorful players in this drama and makes the story particularly accessible to teens, as Taylor follows her career from high school graduation and on through college. As an undergraduate NASA intern, Taunton found herself at the center of the "Mars life" controversy. She gained new friends and mentors, faced strong personal and professional challenges with grace, and joined Taylor in making a significant discovery. At heart, a celebration of life-human, as well as theoretical-this book will appeal strongly to teens.-Christine C. Menefee, Fairfax County Public Library, VA (c) Copyright 2010. Library Journals LLC, a wholly owned subsidiary of Media Source, Inc. No redistribution permitted.



Chapter One Plimpton (as a word, not the man) has a meaning beyond being a man's name, because George Plimpton became a Walter Mitty for the second half of the 20th Century, dabbling in American sports and entertainment. Writers now speak of "doing a Plimpton." It means not only becoming part of the means that your experience becomes the story. William McKeen in Good Stories, Well Told August 8, 1997 After several wrong turns, I pull into what I take to be the proper drive. The sprawling Johnson Space Center near Clear Lake, Texas, just south of Houston off Interstate 45, resembles nothing so much as the campus of a midwestern state college magically transported from 1966. Ugly, nondescript buildings of painted block and textured aluminum squat over a confusing grid of roads, parking lots, and well-tended lawns. Professorial-looking men and women bustle about, frowning at their watches in white J. C. Penney shirts. Here and there, longhaired young people sit cross-legged in the grass, conversing on weighty subjects. Building 13 is a cavernous affair, indistinguishable from the center's other beige crypts save for its large black identifying numerals affixed to one wall. A white tower topped with a tank labeled "Liquid N" stands beside the parking lot. As night falls, floodlights give it a vaguely ominous look, like the guard tower in a prison movie. Over half of Building 13 is devoted to an open hangar, crowded with cranes and hoists. Gleaming devices slated for future Space Shuttle missions, according to public relations posters propped in front of them, sit half assembled and draped in plastic. Signs attached to gigantic machines warn: "Hard Hats Must Be Worn!" and "Caution: Poison Gas." At nine o'clock on a Friday evening, the footsteps of a young chemist -- a paid intern not yet graduated from college -- echo hollowly through the deserted space. When Anne Taunton arrived for work at six this morning, Building 13 was a hive of activity. Engineers pored over diagrams at their desks, shirt-sleeves rolled. Workers in pale blue coveralls eased hand trucks beneath gas canisters, ferrying them to points unknown. But now she and I seem to be the only people here. The long shadow of an articulated manipulator arm lies still upon the floor. I follow her toward the heart of the building, to a tool with which we hope to glimpse a new form of life. Taunton is dressed in jeans, sandals, and an embroidered cotton blouse the same beige color as the walls. Twenty-two years old, she is blond, her face not unlike that of the actress Jenna Elfman except for her wire granny glasses that seem to impart a perpetual squint. She is a well-adjusted, straight-A student from the small town of El Dorado, Arkansas. In mild protest against this fact (and also to pay off a bet made during a charity fund-raiser), last year she had her navel pierced. In it she wears a small ring depicting an Arkansas razorback, the emblem of the university to which she will return in the fall to complete an honors thesis in chemistry. We pass through the assembly area into a long corridor of offices and small laboratories. Taunton turns left, leading me into a darkened room about the size of a classroom at the state university where I teach journalism. The only light comes from two computer monitors connected to a piece of equipment dominating one wall: a $500,000 Philips field emission scanning electron microscope (FESEM). It can magnify images to over 100,000 times their actual size with unprecedented clarity. It captures objects that would be invisible to the most powerful light microscopes. NASA obtained the state-of-the-art machine in 1994 for materials science. Its primary purpose in Building 13 is to analyze structural stress on rocket valves, space shuttle door hinges, and other hardware on which human life in space depends. But by signing up for time during off-hours, any JSC scientist can use the FESEM to look for other things, including extraterrestrial life. Taunton has spent many late nights and early mornings at JSC doing exactly that. She removes four stubs of coated metal from a Tupperware sandwich box. Each holds a tiny pebble. At the center of the electron microscope, a chamber the size of a small microwave oven rests on a table cushioned against movement by a square air bag. Taunton turns a handle and the door slides silently open, supported at each corner by gleaming pistons. A tray holding a stainless-steel disc emerges. She carefully places the stubs into drilled holes on the disc, which already hold three other pebbles. She pushes the assembly closed, seals an air lock, and switches on a noisy vacuum pump. We sit before the two lit monitors. The three pebbles already on the disc come from Mars. They are newly sliced chunks of ALH 84001, the Martian meteorite that captured world headlines exactly one year earlier, when a JSC team led by David S. McKay -- Taunton's boss -- announced the discovery of what appeared to be fossilized bacteria trapped within carbonates in the rock. The other four pebbles are travertine, a carbonate mineral deposited by thermal hot springs. I have collected these over the past month in a series of trips into a mile-long, hundred-year-old drainage tunnel that winds beneath Hot Springs National Park in Arkansas, thirty miles north of my home. Although park literature describes the slightly radioactive water as emerging from great depths "naturally sterile," I have learned enough about hot springs to believe it might be otherwise. With the help of a few dedicated scientists, I have spent much of the previous year looking inside our world, and I have found it to be alive. A vastly diverse class of previously unknown microbes inhabits the deep subsurface of our Earth. These organisms, which I choose to call "dark life," have been found in eaves, mid-ocean volcanic vents, salt domes, Antarctic ice cores, mines, and the deepest holes ever drilled. They form complex ecosystems and food chains wholly independent of sunlight, photosynthesis, oxygen, and other standard requirements for life "as we know it." They draw energy from chemicals (sulfur, iron, manganese, elemental hydrogen), or from the natural radioactivity that abounds within the planet's crust, or from the scant light produced by deep-sea volcanoes. Much of what is known about them has been learned Since 1990. New discoveries occur almost daily. Because the few species studied can endure extremes of heat, pressure, cold, salinity, acidity, and other conditions hazardous to humans, microbiologists have lumped them together under the category "extremophiles" -- but this name is misleading, in that it implies such life is a rare curiosity. In fact, nearly every researcher who goes looking for it finds it, often in great abundance. A few theorists have gone so far as to speculate that these dark ecosystems represent the greatest mass of life on Earth. Placed on one side of a scale, they argue, the deep organisms would weigh more than all five billion humans, all animals, all plants and trees, all fish and plankton and algae, all the far more familiar microbes of our bodies and bathrooms -- more than all of these put together, more than the sum of everything we used to call biology. Dark life is by far Earth's oldest, both in terms of when certain genes evolved and in the life span of particular individuals. Some organisms appear to be, for want of a better word, immortal, remaining dormant for long periods of time, yet continually capable of resurrection. When all available water freezes or evaporates, they hunker in Stasis until it returns. How long is a matter of vigorous debate, but at the low, most conservative end, the number is tens of thousands of years. Some research suggests that the high end is hundreds of millions of years. Shrunken, dried microbes have been revived from ancient salt domes, from sub-Antarctic ice cores, and from NASA gear exposed to the cold vacuum of space. So much living stuff is underground, and so little is known about it, that I was able to enter the Hot Springs tunnel feeling quite optimistic about the chances of an amateur scientist actually finding undiscovered life. July 4, 1997 The summer heat shimmered in waves above the soft, sweltering asphalt. Three friends and I stood in a municipal parking lot a few blocks off the main drag of Hot Springs. We sorted through cardboard boxes in the trunks of our cars, gathering helmets, lamps, thermometers, and pH meters for the expedition ahead. I checked my watch: At that moment, the main chute of the Pathfinder mission to Mars should have been deployed; the spacecraft's air bags should have been inflated. It seemed a good omen in my own search for alien life. My friends adjusted their borrowed helmets. While not exactly renaissance naturalists, we were nonetheless an overeducated bunch, college professors in the fields of communication, theater, computer art, and journalism. Not a biologist among us. But I had recently taken an undergraduate course in microbial collection technique at my university, after assisting in several underground microbial studies. In addition, I possessed the proper gear, twenty years of caving experience, and a biological collection permit from the U.S. National Park Service. And I knew the path to several sites where we were likely to find unknown extremophilic microbes, not quite a mile into the darkness. We descended a steep grassy bank bordering the parking lot, watching for the copperheads that often lounged there, and stepped into a knee-deep rocky stream, its bottom slick and mossy. As Pathfinder bounced over the frozen surface of Mars, we walked upstream to a yawning concrete arch and switched on our headlamps. On September 16, 1541, Hernando de Soto and his dwindling band, ragged from months of wandering through the American wilderness, rode into the village of the Tunicas in what would later be called Arkansas. Tribes from distant lands had gathered there to bathe in the village's sacred springs: Quapaw, Pawnee, Natchez, Choctaw, Osage, and even a few Cherokee who had come from far mountains to partake of the healing waters and to trade. De Soto hoped to barter for corn and other supplies, and, as always, to question the native travelers as to where he might find the gold that had always eluded him. When news of the approaching strangers reached the village, several visiting chiefs had already gathered to prepare a celebration in honor of a recently returned trading party. According to the report of Garcilaso de la Vega, "the young men were for war, but the medicine men claimed that the Great Spirit had revealed to them that the strangers would come in peace." Thus de Soto was allowed to spend a restful month at the springs before marching south. A century later, French trappers stumbled upon the narrow canyon by following a cool mountain stream into which dozens of steaming springs flowed. Natural dams of the mineral tufa, or travertine, circled pools of differing temperatures. These allowed bathers to move gradually from cooler to warmer baths, according to their personal tastes. Unlike the hot springs of Europe, those in the "valley of vapors" did not produce a sulfurous smell, and the water was quite tasty. News of the site spread. By the early nineteenth century, the town of Hot Springs had become a fashionable resort, the "curative" powers of its water touted by the world's leading physicians. Yet both the central stream -- which often flooded as torrents of rainwater poured down the steep canyon -- and the massive tufa dams perched above it stood in the way of the town they had spawned. The nineteenth century had a method for dealing with such inconveniences: paving them over. "The main street was once the bed of a mountain stream....The dispossessed river now flows through a tunnel," Stephen Crane observed when visiting Hot Springs on March 1, 1895. "Electric cars with whirring and clanging noises bowl along with modern indifference upon this grave of a torrent of the hills." The springs had been capped and piped into a central collection reservoir. Hot water was distributed through pipes to a dozen public buildings Crane compared to the mansions of "peculiarly subdued and home-loving millionaires." These glamorous bathhouses stood in a tight row atop the ruins of the ancient pools and dams. Although many of the bathhouses have now fallen into disrepair, they remain, historically preserved as part of Hot Springs National Park. The wild stream still flows, covered by its masonry roof. Few of the tourists who amble down Central Avenue realize what's beneath their feet. Below Bathhouse Row, several natural springs still pour into the stream without benefit of municipal plumbing, coating the walls with yellow and red mounds of travertine. The word "travertine" comes from the Italian travertino, a corruption of tiburtino, meaning "the stone from the city of Tibur." Tibur was the ancient name for Tivoli, a city located west of the Sabine Mountains on the banks of the river Teverone, near Rome. As it ages and hardens, Italian travertine forms a multihued, easily quarried stone that has been used to decorate the Coliseum, St. Peter's Basilica, and bank lobbies around the world. Although the most famous architectural travertines come from Italy, the mineral is quite common elsewhere as well. It is found in many sedimentary, granitic, and volcanic terrains; in and near fault zones; and close to every known natural hot spring, whether active or extinct. Travertine is composed primarily of precipitated calcite and aragonite. The whitish (or occasionally yellowish or reddish) ingredient of most cave formations, such as stalactites and stalagmites, is calcite. Both calcite and aragonite are crystallized forms of calcium carbonate, or CaCO3, the main component of blackboard chalk and antacid tablets. The difference between calcite and aragonite is that the latter is characterized by an orthorhombic crystalline structure, meaning aragonite crystals grow in three dimensions along three mutually perpendicular axes. If you look into a child's bag of jacks, you will see a variety of orthorhombic shapes thrown together like aragonite crystals in travertine. I was looking for travertine in Hot Springs because of a chance conversation I had had with NASA's Carlton Allen, a planetary geologist and lunar expert on David McKay's team. The original NASA paper on the Martian meteorite had put forth four separate lines of reasoning to suggest that microbial remains were trapped inside the rock. To me, and I suspect to most other laypeople, the most striking of the four was the visual one: tiny, rodlike structures that might be the fossils of ancient Martian bacteria. This claim was controversial not only because the structures came from Mars but also because they were so small, of an order of magnitude smaller than any known bacteria. Virtually all biologists felt that nothing so tiny could hold the necessary molecules for the existence of "life as we know it." But Robert Folk, a prominent sedimentary geologist based at the University of Texas and one of the world's leading experts on travertine, insisted that he had photographed many such organisms in sedimentary rocks right here on Earth. He was convinced that these "nanobacteria," as he named them, were, among other things, agents of the chemical reaction that deposits travertine at natural hot springs. (Folk preferred the spelling "nannobacteria," after "nannocrystal" and similar geological terms. McKay had ultimately decided that the prefix nano-, with a single "n," was more widespread in scientific literature. Two other researchers had independently discovered the cryptic spheres and rods at about the same time as Folk; they had independently hit upon the same term, spelling it "nanobacteria." Both prefixes came from the Greek nannos, meaning a small, mischievous old man. By any spelling, many who knew him would consider this an apt description of Bob Folk.) Allen, Taunton, and other members of the McKay team had begun studying travertine from Yellowstone National Park and other locations in an effort to identify living nanobacteria. If they succeeded in extracting DNA, cell walls, or other evidence of life's chemistry in nano-sized objects, such proof would go a long way toward supporting the theory that similar organisms had lived in the meteorite ALH 84001. Not incidentally, this would also prove that a new class of life existed on Earth, one that might have important implications for biology and medicine. I've spent much of my adult life poking into caves and tunnels. Caves provide not only an opportunity for geographic discovery but also an intensely physical awareness of the vastness of geologic time. In much the same way, tunnels -- old aqueducts, sewers, railroad tunnels, mines -- allow explorers to make tactile connection to the geologic eye blink that humanity calls "history." Not long after moving to Arkansas, I began roaming the Hot Springs tunnels, and I'd seen some fine travertine in them. Allen and Taunton had told me they'd be delighted to have a sample of actively depositing travertine from an unsampled area, especially one removed from sunlight. If I collected it, they'd let me drive it down to Houston to watch them prepare and photograph it on the same scanning electron microscope that had given the world the tantalizing images of ALH 84001. So here I was, slogging over slippery rocks where the Osage and the Choctaw once gathered in peace. Above our group hung a two-foot-thick layer of fog. It gradually descended as we moved forward. The air temperature shot up several degrees, and I could hear splashing somewhere ahead. Water, heated geothermally during its 3,000-year course through radioactive rock a mile below, shot from a massive iron pipe with about half the strength of an open city hydrant. Hot trickles and spurts issued in from a dozen cracks, where small springs had jumped the channels laid for them by the tunnel's builders. I stuck a long thermometer into the main flow. The water was well below the boiling point, but, at 146° Fahrenheit, still hot enough to scald. I checked the pH and considered which of the assortment of sampling tools and containers my friends and I had carried would work best for removing tiny chunks of fresh travertine. I noticed an outlet of water high in the ceiling splashing onto a pitch-covered wooden distribution pipe along the wall, its volume that of a shower nozzle turned wide open. The flow had deposited a few centimeters of travertine skin, coating the thick pipe as well as a number of iron bolts and straps that held it in place. I pulled a cold chisel from my pack, dipped the blade in ethanol, and flamed it with a butane lighter. I climbed up onto shaky pipe, holding the sterilized tool out with one arm, taking care not to touch it against anything en route to the closest bolt. Trying to ignore the hot spray that quickly soaked my clothes, I laid the chisel against the tip of a travertine-coated bolt about as big as the end of my thumb. I pulled a short sledge from my pack and gave the chisel a sharp rap. The piece cracked off cleanly. I balanced it on the blade as I eased my way back down to place the sample inside a sterile collection bag held open by one of my colleagues. With a permanent marker I labeled the bag "Iron Nub, Tunnel Spring #1." In the center of the nub, closest to the rusted metal, were alternating bands of color that I hoped might correspond to iron-eating microbes. My friends and I worked our way north, collecting additional stone chips and selecting springs to which I would return later to place glass slides in order to grow fresh accumulations of travertine. We were soon heated to the point where we had to lie down in the cool mountain water just to catch our breath. I dipped my head back into the flow, thinking of de Soto. By now Pathfinder's dish antenna had locked on to a tiny blue speck in the Martian sky. Advances in science, like those of human exploration, rely on ever-shifting combinations of curiosity, technology, and chance. As I lay in the stygian wash, I recalled another subterranean pool I had entered a thousand miles away, nearly a decade earlier, reaching what was then a raw frontier of cave exploration and technology. If caves and tunnels offered me visions of geologic and historic time, they also provided a gateway to my personal past. As with many human explorers who had come before me, my present quest had begun when I entered a new world without recognizing it for what it was Copyright © 1999 Michael Ray Taylor. All rights reserved.