I FIRST WENT TO ANTARCTICA in August of 1968 as a member of a research team led by Dr. Robert Benoit of Virginia Polytechnic Institute and State University. Benoit had been awarded a grant by the National Science Foundation to study the microbiology of a strange group of permanently ice-covered lakes located in the rugged coastal valleys (now called the McMurdo Dry Valleys) near the Ross Sea. The lakes had been discovered by the first expedition of the great Antarctic explorer Robert Falcon Scott (1901-4), but only a few scientists had visited them in the intervening years and little had been written about them in the scientific literature. In 1968, I was a graduate student at work on a project in physical chemistry and nearly a year away from completing my doctoral program. When I heard that Benoit and his graduate assistant, Roger Hatcher, needed a chemist, I quickly volunteered, thinking that this would be a wonderful way to learn something about limnology, the science of lakes, and to explore a part of the world that I would most likely never see again.

      From the outset, I found the science, and indeed, everything about the Antarctic continent, fascinating. It was the most austere and beautiful land I had ever seen, and I was drawn to it immediately, in ways and for reasons I did not understand. When I was not analyzing the unimaginably clear waters of Lake Vanda or Lake Bonney, two of the ice-covered lakes we had come to study, I was walking and thinking and writing page after page of notes in my journal, trying to describe what I was seeing and feeling in this improbable Eden of ice and stone. My words seemed always to fall short, and seem to do so to this day.

      The years passed after that first encounter, but the lakes and the valleys of Antarctica remained vivid memories, a daydream away. Gradually my professional interests turned from the pure laboratory chemistry in which I had been trained to the science of geochemistry. From the courses that I was teaching and from the Midwestern lakes that I was studying, new questions began to arise. I began to think that the answers might lie in the distant waters of the Dry Valleys that I had once visited with Hatcher and Benoit.

      In 1980 the National Science Foundation funded my proposal to study the behavior of nutrients (compounds of nitrogen and phosphorus that control the biological productivity of a lake) and heavy metals (elements such as manganese, iron, cobalt, nickel, cadmium, and lead) in Lake Vanda and its inflow, the Onyx River. This turned out to be the beginning of a ten-year investigation that gradually encompassed more lakes and more subtle and vexing questions. How and when had these odd water bodies evolved? Why were they so different in their chemical compositions? How were they sustained biologically in such a harsh environment? How were the chemical elements transported to them, and how were those elements removed? Because they were so biologically uncomplex, might these lakes not serve as beautifully simple models for other bodies of water on the Earth? Perhaps even the oceans? Because they seemed to cleanse themselves of the metals brought into their waters, might they not tell us something about the way the Earth regenerates itself? These were some of the questions that brought me back to Antarctica five more times during the 1980s and, most recently, from October to December of 1994.

      Thus the present book draws on more than fourteen months of journal notes collected over seven field seasons. It arose, I think, from the need to talk about the Antarctic work in a more reflective and personal way—in a way that could not easily be accommodated within the pages of professional journals. From the outset, the continent raised questions for me that went beyond the purview of science. These were questions about the ways we experience the world and respond to its physical settings; how we decide, as individuals, to do with our lives what we do with them; the sources of our wonder; the nature of science itself. If the book appears to have a spiritual dimension, that seems only fitting, given the place in which it was written. For Antarctica is the most sublime of continents, a land of light and darkness, of scrawls and traces and hints of eternity.

      The language and ideas of chemistry, geochemistry, and limnology figure prominently in these pages. I hope they will not prove distracting to the reader. I believe there is a certain beauty to the sound of the names of the chemical elements and to the names of common field equipment and laboratory objects—the “trim and tackle” of the work. And of course the ideas themselves, pure creations of the human mind, are things of uncommon beauty. But this is not meant to be a book about those specific sciences. Nor, despite its reminiscences of family and childhood in Pennsylvania, is it meant to be a memoir. Though somehow, through the detours of writing and the strange ways of the heart, science and memory—indeed, science and life—have tangled themselves together in its pages.

      In nature, the great geochemical cycles rarely turn exactly back upon themselves. So it seems with life. In the end, we are home but not in the same place. If this book is in some sense a travelogue, the journey it describes is very much a “heraclitean” one. The stream we had hoped to step in is no longer there.

      I should note that our work occurs within a very small and atypical region of the Antarctic continent. The McMurdo Dry Valleys—located about seventy miles west of Ross Island and the major U.S. base, McMurdo Station—occupy only a tiny niche (1,500 square miles in a continental area of 5.5 million square miles) at the edge of the great ice sheet that covers most of Antarctica. The valleys were carved by the advance and retreat of glaciers that moved down from the Polar Plateau, but they have been ice-free for some four million years. In these cold, arid, ferociously windswept, and virtually lifeless valleys lie the lakes and the few ephemeral streams that feed them: Lakes Miers, Fryxell, Hoare, and Vanda are the settings for much of what occurs in the book.

      Two limnological terms appear early on, and it may be helpful to define them here. In the temperate zone, deeper lakes tend to stratify in summer. The warmer, less dense, and, typically, oxygen-rich waters that lie near the surface are referred to collectively as the epilimnion. The cooler, denser, and often stagnant lower waters are called the hypolimnion. This usual stratification pattern—warm waters at the surface, cool waters below—is reversed in the lakes of the McMurdo Dry Valleys.

      water,

      ice and

      stone

      ONE

      Ohio: West and South

       Ohio has had its autumn glory. The leaves of the burning bush beyond the sun room had hung like blades of fire for more than two weeks. At Hueston Woods, from the stream-carved valley of Little Four Mile Creek, you could look up walls of late Ordavician shale and limestone into the canopies of orange maples and plum-colored beech, into a crisp expanse of sky that lay as cloudless as a blue canvas behind the brilliant trees. This morning, though, out over

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