For Love of Lakes

Limnos I—Walden Pond, Massachusetts

· · 16 · · Limnos I—Walden Pond, Massachusetts Alakeisthelandscape’smostbeautifulandexpressivefeature.Itis earth’seye;lookingintowhichthebeholdermeasuresthedepthof hisownnature. HENRY DAVID THOREAU, 1854 I first learned of Henry David Thoreau in high school English class. He seemed an odd sort, squirreling himself away in a tiny cabin by a lake, refusing to pay taxes to support a war against Mexico he opposed, an act of civil disobedience that cost him a night in jail, a writer who refused to hold a steady job, a social misfit who loved nature, particularly that small lake, Walden Pond. I rediscovered him while searching for a pithy quote to use in a talk I was preparing decades ago on the lakes of Minnesota’s Boundary Waters Canoe Area. I found my quote; it tops this page. I also discovered a Thoreau I never knew, an endearing bundle of contradiction, and our first and foremost lake watcher. He describes his famous pond as “a gem of the first water which Concord wears in her coronet. . . . It is like molten glass cooled but not congealed, and the few motes in it are pure and beautiful like the imperfections of glass. . . . Not a fish can leap or an insect fall on the pond but it is thus reported in circling dimples, in lines of beauty, as it were the constant · · 17 · · upwelling of its fountain, the gentle pulsing of its life, the heaving of its breast.” He sees the lake through the lens of emotion expressed in the language of the poet. Thoreau, despite his romantic expressions and protestations to the contrary, also saw lake through the window of reason, of science. He is not usually thought of as a man of science. Academic credentials notwithstanding , that is oversight. Intensely curious and an acute observer, he had the mind-set of science. Particularly in his later years, Thoreau tended toward increasingly objective observations of local natural history. In addition to significant original writings on forest succession, dispersal of seeds, and other aspects of terrestrial ecology, Thoreau also developed insights into limnology, the study of lakes. (Limnos means “lake” in Greek.) Walden contains some of the earliest objective observations on the nature of lakes. When town folk concluded Walden to be bottomless, Thoreau rejected such nonsense, tied a rock to a rope, and discovered its maximum depth to be 102 feet. A part-time surveyor, Thoreau calculated Walden’s surface area at 61.7 acres. Limnologist Edward Deevey, in 1939, with more sophisticated equipment, measured 61.3. Thoreau discovered that lake temperatures change with depth. He linked the increase in water temperature that occurs over sand bars beneath ice to sunlight reflecting off the bottom. He was the first to record the phenomenon of streaks of foam formed on a lake by a strong wind, now known as Langmuir spirals. Thoreau noted the differences between lakes rich in nutrients and those nutrient-poor, known today as eutrophic and oligotrophic lakes, respectively. His descriptions helped my students visualize these two principle lake types. Coupled with his many observations of fish, aquatic plants, and other creatures in Walden and other lakes, Thoreau’s scientific accomplishments are impressive. Deevey wrote, “It has been shown that Thoreau’s curiosity was unusually fruitful when directed toward lakes . . . so that the Concord individualist may with justice be called America’s first limnologist.” Thoreau’sobservations,however,likethoseofcredentialednaturalhistory professors of his day, were purely descriptive. Thoreau, like the others, limnos i—walden pond, massachusetts landscapes· · 18 · · saw lake as a body of water and a catalog of individual living things, not as functional relationships. • • • Ironically, as a self-professed mystic, transcendentalist, and natural philosopher , Thoreau railed against the growing insistence of science in his day that the cold hand of objectivity, devoid of human feeling, was the exclusive path to truth. “The inhumanity of science concerns me, as when I am tempted to kill a rare snake that I may ascertain its species,” he wrote. Nature, according to Thoreau, was not detached from self. “The point of interest is somewhere between me and them,” he wrote. My training in science demands fealty to the standards of reason as the legitimate path to the hard bottom of truth. Instinctively, I distrust the claptrap of emotion. My mind sees the pitfalls of romanticism, of blindly following innate inclinations, in the mucous trails left by slugs on a bike trail a few blocks from my house. Why so many of these wayward mollusks forsake the vegetated sanctuary on one side of...