BOOKS· nase, which converts N 2 gas into ammonium ion (NH 4 + ). The nitrogen-fixing organisms in the soil have a symbiotic relationship with many plants, growing on their roots and providing a fertilizing effect. Wolfe recounts how in the early 1900s, as nitrogen was gaining in economic imporquantities near deep-sea hydrothermal tance both as a fertilizer for crops and as TALES FROM THE UNDERGROUND, by vents and deep within Earth's crust, adding an essential component of trinitrotoluene David W.Wolfe, Perseus, 2001,221 pages,to the idea that thefirstsparks of life may (TNT), German chemist Fritz Haber came to the rescue with a catalytic route—still have appeared in such environments. $26 (ISBN 0-7382-0128-6) At some point after the individual build- used today—for fixing nitrogen via a proing blocks of life were assembled, they ori- cess that required very high temperature REVIEWED BY JULIE GRISHAM and pressure (C&EN, Aug. 20, ented themselves into patterns. page 61). But today, after Free-floating amino acids are éé ^ ^ NE DOESN'T HAVE TO VENalmost 100 years of trying to ture far into the under- just the start: They must string develop alternatives, Wolfe ground for new discover- themselves together in order writes, "we humans still have to make proteins. Wolfe disies," begins David W. not come up with a way to fix Wolfe in his book "Tales cusses the theory, proposed by nitrogen at room temperature from the Underground: ANatural History Graham Cairns-Smith of the as the microbes do with their of Subterranean Life." Apinch of soil from chemistry department at the amazing nitrogenase enzyme." the average backyard contains close to 1 University of Glasgow in ScotAlthough some subterranebillion individual living organisms, as many land, that clay played a crucial an organisms, such as those role in the origin of life. In as 10,000 distinct species of microbes— that make nitrogenase, have many of those not yet named, cataloged, this proposal, electrostatically been well studied, there are or understood. Current data suggest that charged clay surfaces provided the total biomass of life underground is catalytic sites for primitive nucleic and thousands of others that have not been amino acids, and the organized structure characterized at all. One argument often much greater than that above. In Wolfe's educational and engaging of clay crystals served as a template for made by environmentalists in favor ofprebook, he covers a range of topics related to sequencing simple proteins and genes. serving the biodiversity of rain forests is underground ecology,frommicrobes that Wolfe acknowledges that Cairns-Smith's that there are potentially tens of thoucould yield new drugs and other products hypothesis is controversial, but says data sands of life forms still to be classified and studied, and any one of them may yield to fungi that help plants obtain water and to support it are beginning to trickle in. nutrients to prairie dogs and other burA key player in the origin and mainte- drugs or other products capable of prorowing vertebrates that play an important nance of life is nitrogen, and a chapter in longing and improving human life. Wolfe role in grassland ecosystems, yet are threat- Wolfe's book focuses on nitrogen fixation, makes essentially the same argument ened because of a decades-long poisoning the process by which inert N 2 gas is con- about soil. campaign by ranchers. Wolfe, an associate verted into a form that organisms can use In fact, the soil already has yielded many professor of plant ecology in the depart- to build amino acids and other nitrogen- products that have been extremely benement of horticulture and a member of the containing molecules essential to life. Only ficial to humankind. "Few people realize biogeochemistry program at Cornell Uni- a few soil and marine microbial species are that most of the natural antibiotics in use versity, begins with the origins of life capable of fixing nitrogen, all of them today are produced by soil bacteria," he and ends with an overview of current through use of the same enzyme, nitroge- writes. SelmanWaksman, who discovered threats to the environment. He covers all of these subjects in a lively manner that should be appealing to scientists and nonscientists alike. In Earth's infancy, it was a pretty inhospitable place. How life as we now know it first evolved in an atmosphere of hot gases, meteor bombardment, and intense ultraviolet radiation is difficult to fathom, and Wolfe puts forward the theory that quite possibly the only safe place to be was underground. "The underground was also the place where the essential ingredients for primitive biochemistry were to be found, and where today we find bizarre microbes believed to be the direct descendants of Earth's first life forms," he writes. Hydrogen, methane, ammonia, and other compounds that are needed to create the basic BILLIONS AND BILLIONS Every pinch of backyard soil contains nearly a building blocks of life are found in large billion microorganisms, many not yet named or cataloged.
DISCOVERIES BENEATH OUR FEET
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BOOKS· streptomycin and several other drugs and Illinois, Urbana-Champaign, microbiology who coined the word "antibiotic" in the professor Carl R. Woese, whose study of 1940s, was a soil biologist. He discovered methanogens—microorganisms that pro that soil microbes produce both growth- duce methane as a by-product of their promoting substances and growth-inhibit metabolism—led to a re ing ones, and that those growth-inhibiting classification of the tree substances (which he called antibiotics) of life. Woese replaced were effective against microorganisms that the long-held five-king were closely related to pathogens that cause dom tree (bacteria, pro human disease. tozoa, plants, fungi, and In addition, many components of soil animals) with three do are capable of suppressing plant disease mains, or superkingdoms: and preventing damage by pests. One of bacteria, archaea, and the most well known is the toxin made by eukarya. His scheme is the beLCtenumBacillustburingiensis, whichgenerally accepted by has been used for years as a natural pesti microbiologists, although cide and more recently has been geneti there are some skeptics. cally engineered into several types of Wolfe'sfinalchapter dis crops. cusses soil erosion, con Wolfe devotes chapters to several other servation and land management, and the topics, including extremophiles (organisms pollution that threatens all ecosystems, found in harsh or extreme environments, including those underground. many of which are the target of "bioSome 500 years ago, Leonardo Da Vinci prospecting" by biotechnology firms in said, "We know more about the movement search ofnew enzymes); earthworms; fungi; of celestial bodies than about the soil and larger creatures such as prairie dogs, underfoot," and Wolfe believes that is still black-footed ferrets, and burrowing owls. true today. More recently, Wolfe says, He also allocates a chapter to University of before Jacques Cousteau invented the
Aqua-Lung underwater breathing appara tus, we had little information about life under the oceans. Nearly 60 years after that invention, oceanography continues to be a growing field, and the ocean is yielding diverse commodities such as beauty products, new foodstuffs, and even po tential drugs to treat can cer. Certainly no one would consider the ocean lifeless. Wolfe foresees a time in the future when people who are now, per haps, "surface chauvin ists" will look at the earth as they do the ocean. Then, hewrites, "Gazing out over a barren plain becomes an experi ence similar to that of gazing out at a wide expanse of turquoise sea." For every per son who reads his book, Wblfe goes a long way toward reaching that goal. •
"Gazing out over a barren plain becomes an experience similar to that of gazing out at a wide expanse of turquoise sea."
J u lie G risha m, a science writer based in New York City, writes frequently about biological and medical research.
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