Arctic Dreams Read online

  To grasp the movement of the sun in the Arctic is no simple task. Imagine standing precisely at the North Pole on June 21, the summer solstice. Your feet rest on a crust of snow and windblown ice. If you chip the snow away you find the sea ice, grayish white and opaque. Six or seven feet underneath is the Arctic Ocean, dark, about 29°F and about 13,000 feet deep. You are standing 440 miles from the nearest piece of land, the tiny island of Oodaaq off the coast of northern Greenland. You stand in each of the world’s twenty-four time zones and north of every point on earth. On this day the sun is making a flat 360° orbit exactly 23½° above the horizon.

  If we could stay within the limits of this twenty-four-hour day and if you could walk down the 100th meridian, toward Mexico City, you would notice at first very little change in the sun’s path around the sky. Soon, however, you would begin to sense that the sun’s orbit was tilted, its arc higher in the southern sky and lower in the northern sky. The tilt of the sun’s arc would become more and more pronounced as you walked south. When you reached the vicinity of Garry Lake in the Northwest Territories, where the 100th meridian crosses a line of latitude at 66°33’N (the Arctic Circle), the sun would have dropped low enough to touch the northern horizon behind you for the first time. You would be far enough into a time zone now for it to make a difference, and that moment when the sun touched the horizon would be “midnight.” At the same spot twelve hours later, the sun would stand 47° above the southern horizon; it would be “noon,” local time. You would say, now, that the sun seemed more to move across the sky than around in it. It has begun to slip below the northern horizon; from here, still walking south on June 21, you would start to experience “night.” Short nights, only prolonged periods of twilight really, at first. But slowly the twilight would start to deepen during the evening hours and to wax in the morning hours. Somewhere on the plains of Manitoba you would finally sense “the middle of the night”—enough of real darkness so you couldn’t continue walking without fear of stumbling.

  If you carried on, as you could if we held June 21 in suspension like this, you would begin to notice three things: the nights would get noticeably longer; the sun would stand higher and higher in the southern sky at noon (and more clearly seem to “rise in the east” and “set in the west”); and periods of twilight at dawn and dusk would shorten, until twilight would be only a passing phenomenon. The sun rises and sets sharply in Mexico City. Sunshine is a daily, not a seasonal, phenomenon, as it is in the North.

  If you stood at the North Pole six months later, on December 21, the winter solstice, the middle of the polar night, you would not see a single star set—they would all pass before you from left to right. If they left behind the light-streak traces they do on time-exposed film, you would see the varicolored rings stacked one atop another, parallel to the horizon, shrinking in diameter, until the last ring, less than 2° across and traced by Polaris, circled the dark spot of empty space that lies over the North Pole.

  If you walked south from the Pole on December 21, you would find the phenomena of six months earlier reversed. It would be utterly dark at the Pole on that day. On the plains of Manitoba the balance of day and night would feel right to you if you were familiar with the short days of winter in the Temperate Zone. In the tropics there would again be days and nights of equal length, with very little twilight.4

  You would have to walk a very long way south on December 21, 1611 statute miles, all the way to the Arctic Circle, to actually set eyes on the sun. The winter darkness, however, would not be complete. Prolonged periods of twilight penetrate the long arctic night, and the strength of even scant illumination from the stars is enhanced all winter by the reflective surfaces of ice and snow. Too, there is no forest canopy to dim the land and, save in a few places, no night shadow of a mountain range to contend with. The Arctic is like the desert in this way—open, unobstructed country, lit well enough by a full moon to permit travel at night.

  It makes little sense in more southerly latitudes to dwell on a consideration of twilight, but it is meaningful in the Arctic, where this soft light lingers for such long periods of time that astronomers distinguish several types.5 In the Temperate Zone, periods of twilight are a daily phenomenon, morning and evening. In the Far North they are (also) a seasonal phenomenon, continuous through a day, day after day, as the sun wanes in the fall and waxes in the spring. In the Temperate Zone each day is noticeably shorter in winter and longer in summer but, still, each day has a discernible dawn, a protracted “first light” that suggests new beginnings. In the Far North the day does not start over again every day.

  In 1597 the icebound and shipwrecked Dutch explorer Willem Barents was forced to overwinter with his crew in wretched circumstances at the northern tip of Novaya Zemlya. They awaited the return of the sun in a state of deep anxiety. More than the cold they hated the darkness; no amount of prolonged twilight could make up for the unobstructed view of that beaming star. They quoted Solomon to each other: “The light is sweet; and it is delightful for the eyes to see the sun.” When the sun finally did appear it came twelve days earlier than they expected. They acknowledged a divine intervention. They gestured toward it with joy and disbelief, and took courage against their difficulties from its appearance.

  What they saw that January day, we now know, was not the sun but only a solar mirage—the sun was still 5° below the horizon, its rays bent toward them by a refractive condition in the atmosphere. Such images, now called Novaya Zemlya images, are common in the Arctic. They serve as a caution against precise description and expectation, a reminder that the universe is oddly hinged.

  If, at the termination of this imaginary southward journey through the realms of winter and summer light, you were to turn around and come back, you would notice many changes in the biological life around you. The total number of species of animals and plants (biological diversity) would diminish—strikingly so by the time you reached the arctic regions. Overall biological productivity (annual number of offspring per species) would also fall off. And the timing of the birth of young would be related increasingly to the cycle of the seasons. The various strategies animals use to survive, to procreate, feed, and protect themselves from the climate, would also change. The long-term biological stability of the ecosystems would decrease. You would travel from a land in which the four seasons are phantoms; from jungles of towering hardwood species where water is always a liquid, trickling somewhere; and where the list of animals is voluminous but unfinished. You would arrive, finally, in a land of seasonal hibernation, of periodically frozen water and low, ground-hugging trees, where the list of mammalian denizens is short enough to memorize in a few moments.

  The overall impression, coming from the South, would be of movement from a very complex world to a quite simplified one—there would come a moment when you passed from the mixed forests of the South, where no one kind of tree stood out, into the coniferous forests where trees of only one or two kinds existed, imparting a single shade of green to a hillside. But this sensation of simplicity would be something of an illusion. Arctic ecosystems have the same elegant and Byzantine complexities, the same wild grace, as tropical ecosystems; there are simply fewer moving parts—and on the flat, open tundra the parts are much more visible, accessible, and countable. The complexities in arctic ecosystems lie not with, say, esoteric dietary preferences among 100 different kinds of ground beetle making a living on the same tropical acre, but with an intricacy of rhythmic response to extreme ranges of light and temperature. With the seasonal movement of large numbers of migratory animals. And with their adaptation to violent, but natural, fluctuations in their population levels.

  In traveling north from the tropics, however, we would still find that broad-scale changes apparent to our eyes suggested an undeveloped country. To the unscientific eye the land would seem to have run out of the stuff of life—running water, light, warmth—to have reached absolute limits. It would seem to offer few niches for animals to occupy. As for the human animal, there would seem to be no such nurturing recesses at all. But there are niches here; and they are filled by animals completely and comfortably at home in them. (The awe one feels in an encounter with a polar bear is, in part, simple admiration for the mechanisms of survival it routinely employs to go on living in an environment that would defeat us in a few days. It is also what impresses someone on an arctic journey with Eskimos. Their resourcefulness, as well as their economy of action, bespeak an intense familiarity with the environment. Of course, they are the people there.)

  On our journey north we would notice significant changes in the soil under our feet. Soil is a living system, a combination of dirt (particles of sand, clay, and silt) and decaying and processed organic matter. It is created by erosion, fracture, and the secretion of organic acids; by animals and plants like beetles (saprophages) and mushrooms (saprophytes) that break down dead matter; and by the excretions of earthworms. It draws in oxygen like an animal, through myriad tunnels built by ants, rodents, and worms. And it is inhabited throughout by hundreds of creatures—nematodes, mites, springtails, and soil bacteria and fungi.

  In the tropics, saprophages and saprophytes break down organic matter quickly. The recycling of nutrients (phosphorus, sodium, and potassium) is so swift that little soil remains behind. In the Temperate Zone, the turnover in organic matter and the recycling of nutrients are much slower, especially in winter, when cold-blooded soil organisms are lethargic or inactive. As a result, rich, deep layers of humus build up over a reddish, sterile clay base familiar from the tropics. To the north these fertile layers of humus give way to firmer, less fertile brown soils, because of a reduction both in the numbers and kinds of saprophages and saprophytes and in aerating and soil-building organisms that can adapt to the loss of solar energy. These acidic podzols of the boreal forests and prairies reach their northern limit at the tree line, where one first encounters the inhospitable soils of the tundra.

  Almost everywhere you wander on the open tundra you find whole dead leaves, preserved flower parts, and bits of twig, years of undisturbed organic accumulation. Decomposition in the Arctic is exceedingly slow, work that must be accomplished by even fewer organisms operating for even shorter periods of time—but since overall biological production is not nearly what it is in the Temperate Zone, little humus builds up. Arctic soils are thin, acidic, poorly drained, and poorly aerated. They are rich in neither the nitrogen nor the phosphorus essential for plant growth. (The soil at fox dens and at the slight rises on the tundra that snowy owls and jaegers routinely use as perches while eating their prey is an exception. The concentration of nutrients at these “organic dumps” accounts for the sometimes luxuriant growth of grasses and the bright display of summer wildflowers at these spots.)

  So: the soils would change in depth and quality beneath our feet as we came north. And the different kinds of animals and plants living within and upon the soil, less and less able to adapt to the reduction of solar energy, would dwindle. And the ones that remained would work slowly or not at all in the dark and cold. If we kept walking, we would eventually stand in a country without the earthworm or the carrion beetle, a place where earth and decay are almost unknown, on the lifeless gravels of the polar desert.

  Traveling north from the equator you could not help but notice, too, the emergence of recognizable seasons, periods of time characterized by conditions of rising, falling, or relatively stable light, in association with certain ranges of temperature. By the time you entered the Temperate Zone you would find a set of seasons distinct enough to be named and easily separated. Farther north, “spring” and “fall” would seem increasingly transitory, until each became a matter of only a few weeks. Winter, you would eventually find, lasted appreciably longer than summer. And together the two would define the final landscape.

  The seasons are associated in our minds with the growth of vegetation. Outside of the four primary seasons (a constant referent with us, a ready and seemingly natural way to organize our ideas), we speak of a growing season and of a fallow season, when we picture the earth lying dormant. In the middle of an arctic winter, however, there is such a feeling of a stone crushed beneath iron that it is hard to imagine any organism, even a seed, living, let alone lying fallow. In summer, in the sometimes extravagant light of a July day, one’s thoughts are not of growth, of heading wheat and yellowing peaches, but of suspension, as if life had escaped the bounds of earth. In this country, which lacks the prolonged moderations between winter and summer that we anticipate as balmy April mornings and dry Indian summer afternoons, in this two-season country, things grow and die as they do elsewhere, but they are, more deeply than living things anywhere else, seasonal creatures.

  The trees are no exception. The northern limit of the continental forests in North America seems anomalous if you try to make sense of the tree line. The boundary sweeps southwest from Labrador to pass beneath James Bay, then turns northwest, crossing Canada’s Precambrian Shield and paralleling the Mackenzie River Valley nearly to the Arctic Ocean before zigzagging west through the valleys of the Brooks Range and the Kobuk River to Norton Sound. The explanation for the irregularity of the line lies with the seasonal climate—it marks the average southward extension of arctic air masses in summer.

  The far northern trees, like the animals, constitute a very few species—willows growing in valleys where they are protected from the wind and a dwarf form of birch. Along the tree line itself, the only successful strategists are species in the pine and birch families. Their numbers thin out over a span of several miles, with trees persisting farther north in isolated patches where there is a fortuitous conjunction of perennially calm air, moisture, and soil nutrients. Islands of trees in the tundra ocean.

  The growth of trees in the Arctic is constrained by several factors. Lack of light for photosynthesis of course is one; but warmth is another. A tree, like an animal, needs heat to carry on its life processes. Solar radiation provides this warmth, but in the Arctic there is a strong correlation between this warmth and closeness to the ground. In summer there may be a difference of as much as 15°F in the first foot or so of air, because of the cooling effect of the wind above and the ability of dark soils to intensify solar radiation. To balance their heat budgets for growth and survival, trees must hug the ground—so they are short. Willows, a resourceful family to begin with, sometimes grow tall, but it is only where some feature of the land stills the drying and cooling wind.

  Lack of water is another factor constraining the development of trees. No more moisture falls on the arctic tundra in a year than falls on the Mojave Desert; and it is available to arctic plants in the single form in which they can use it—liquid water—only during the summer.

  Permafrost, the permanently frozen soil that underlies the tundra, presents arctic trees with still other difficulties. Though they can penetrate this rocklike substance with their roots, deep roots, which let trees stand tall in a windy landscape, and which can draw water from deep aquifers, serve no purpose in the Arctic. It’s too cold to stand tall, and liquid water is to be found only in the first few inches of soil, for only this upper layer of the ground melts in the summer. (Ironically, since the permafrost beneath remains impervious, in those few weeks when water is available to them, arctic trees must sometimes cope with boglike conditions.)

  Trees in the Arctic have an aura of implacable endurance about them. A cross-section of the bole of a Richardson willow no thicker than your finger may reveal 200 annual growth rings beneath the magnifying glass. Much of the tundra, of course, appears to be treeless when, in many places, it is actually covered with trees—a thick matting of short, ancient willows and birches. You realize suddenly that you are wandering around on top of a forest.

  Virtually all of the earth’s biological systems are driven by solar radiation. As the light falls, so must the animals and plants arrange their growth and daily activities. The Arctic receives, strangely, the same amount of sunshine in a year as the tropics, but it comes all at once, and at a low angle of incidence—without critical vigor. The regular rhythm of light-fall in the tropics, that predictable daily infusion of energy, together with its high angle of incidence, are the primary reasons for the natural stability of these ecosystems. The rainy season aside, temperature and humidity on a day in May are not so different from temperature and humidity on a day in December. The animals and plants have evolved breeding and feeding strategies, of course, that depend on this almost uninterrupted flow of light.

  In the Temperate Zone, periods of daily light-fall are not equal during the year. The animals and plants must adjust to a seasonal way of life. In the Arctic this situation becomes much more extreme. Periods of light-fall can’t readily be divided into days. The average temperature fluctuates over a period of 365 days, not twenty-four hours; sources of water are frozen; and the dim light puts a special burden on animals that must use their eyes to search. The very rhythm of light itself creates a difficulty. Most animals live lives in biological keeping with the earth’s twenty-four-hour period of rotation. They have neither the stamina nor the flexibility, apparently, to adapt to the variable periods of light they encounter in the Arctic’s nightless summer and dayless winter.6