Often whales and seals and otters are the hottest things around. A Weddell seal, a thousand pounds of fur and blubber and heart and lung and rete mirabile, might lie on the Antarctic ice, open the shunts that let warm blood flow through its blubber, and create above it a cloud of steam. After a time, bored or hungry or spooked by a nosy human, it might flop from the ice into the water. It might leave behind the marine mammal equivalent of a snow angel, an outline of itself melted into the ice, a negative image of belly and fins and head in three dimensions. The Weddell seal thumbs its nose at the cold, leaving in the ice an image that is often called a seal shadow.
It is December sixteenth, and the mercury hovers around zero near Lynx Lake, ninety miles north of Anchorage. Wind from the north has broken the heat wave, sending the El Niño warmth scurrying south. We ski across one frozen lake after another: Ardaw, Jacknife, Bald, Frazier, Little Frazier, Lynx. There are three of us: myself, my son, and a companion, the same woman who joined me on Ben Nevis in September, the woman with Raynaud’s disease. Between the lakes, we ski across spits of snow-covered land, what would be canoe portages during the summer. The snow is thin. In places, we ski on patches of exposed ice. We pass a place where my son and I camped in August, huddled in a tent in the rain next to our canoe. Some of the lakes are joined by frozen creeks that run through frosted peat bogs and iced-over marshes. Marsh plants sticking above the snow have sprouted ice flowers — blossoms of white ice poking through dry brown stems. The stems, just before they freeze, hold liquid water. As the water freezes, it expands, bursting out of the stems, forming these blossoms. The freezing water draws liquid water behind it, and the blossoms grow. The blossoms here are the size of Ping-Pong balls, but I have heard of ice flowers as large as baseballs.
We cross a set of moose tracks, a beaver lodge, fox tracks. I watch and listen for birds but see and hear none. The air is still. If we stop, the world seems muffled. Sound is nothing more than changes in pressure. Pound a drum, and the air beneath the drum is compressed and released. Speak, and the vocal cords compress air in the larynx. The compressed air moves outward in a wave. As sound waves travel past snow, they momentarily increase the air pressure, forcing air into pores between snowflakes and ice crystals. As the pressure of the sound waves drops, the air moves out of the pores. The air is moving in and out a hundred times per second at a low pitch, five thousand times a second at a medium pitch, and eighteen thousand times a second at a high pitch, near the edge of human hearing. With each movement in and out of the snow, energy is lost. The snow has swallowed the sound. When we move, our skis drag across the snow, torturing it, making it scream with every gliding motion. At warmer temperatures, it is more of a crunching sound, but near zero the pitch increases. It becomes more akin to the sound of fingernails on a chalkboard. The crystal structure is stronger. What we hear is the sound of ice crystals being crushed and torn. This screeching is the sound of hydrogen bonds unbonding under the weight and movement of our skis.
Between two lakes, we ski on a creek. The ice sounds hollow. In places, the snow has blown away, and I can see that we are skiing on three inches of ice, under which there is six inches of air, and under the air, more ice. When the creek was freezing, the water level was dropping. The space between is more than big enough for muskrats.
I worry as we move toward an unseen cabin. Earlier, I had trouble with the car. I had forgotten certain gear. I had expected warmer temperatures. And I had hoped for more snow. If a breeze comes up, these cold temperatures will turn brutal. There will be windchill, but also blowing snow, the thin layers of it lifted off the ice, sand-blasting exposed skin. I worry about chilblains, the nasty blistering and sores that can erupt when fine blood vessels constrict in the cold and leak blood beneath the skin. I worry about frostnip and frostbite. I worry about hypothermia and death by exposure. It was not far from here that Andrew Piekarski died under his lawn mower, pinned to the ground while he slowly froze to death, way back in September.
And I have in my mind something J. Michael Yates, a poet and playwright, wrote of a man who “has been moving north always…. On his back he carries pack, snowshoes, and rifle.” The man dies:
A man, warmly dressed, in perfect health, mushing his dogs a short distance between two villages, never arrives. He has forgotten to reach down, catch a little snow in his mitten, and allow it to melt in his mouth.
For a reason neither he nor his dogs understand, he steps from the runners of his sled, wanders dreamily — perhaps warmly, pleasantly — through the wide winter, then sits to contemplate his vision, then sleeps.
The dogs tow an empty sled on to the place at one of the two villages where they’re usually fed.
While those who find the frozen man suspect the circumstances of his death, always they marvel that one so close to bed, warmth, food, perhaps family, could stray so easily into danger.
My son, ten years old, is not worried at all. I make him stop to drink water and eat chocolate. I remind him to let me know at the first hint of a chill, of cold toes, of stiff fingers. I want to know right away, before he becomes really cold. Later, he complains of cold cheeks, and we stop. I check his face for patches of white, then rub my fingers across his skin looking for hard patches, for any sign of stiffness. There is nothing.
“You told me to tell you right away,” he says. “But I’m not that cold.”
We ski on.
In 1911, Robert Falcon Scott was in Antarctica, waiting for summer so that he could start what would prove to be his fatal walk to the South Pole. Scott sent Apsley Cherry-Garrard, Edward “Bill” Wilson, and Birdie Bowers to Cape Crozier in July, the height of the Antarctic winter. Their mission: to bring back eggs from an emperor penguin colony. “They are extraordinarily like children,” Cherry-Garrard later wrote, “these little people of the Antarctic world, either like children, or like old men, full of their own importance and late for dinner, in their black tail-coats and white shirt-fronts — and rather portly withal.” The men hauled a sled sixty miles in the dark at temperatures of seventy below. Their tent blew away in a storm, and for a time the men lay in a snowdrift singing hymns and waiting to die. But in the end, they survived. They observed the birds at the nesting colony. Cherry-Garrard felt compelled to mention the tenacity these birds showed in caring for their eggs and young. “Now we found that these birds were so anxious to sit on something,” he wrote, “that some of those which had no eggs were sitting on ice! Several times Bill and Birdie picked up eggs to find them lumps of ice, rounded and about the right size, dirty and hard.”
The men carried three eggs back to Scott’s base, and the eggs now sit in London’s Natural History Museum. Emperor penguins may look ridiculous, standing in the cold, mistakenly sitting on rounded blocks of ice, but Cherry-Garrard and his companions must have looked more ridiculous still, pulling their sled through the dark, resting in frozen sleeping bags, very quickly reaching a point at which they wished for the comfort of their own deaths. The penguins, meanwhile — without bags, without parkas, without kerosene or a stove to burn it in — maintained a body temperature of ninety-nine degrees. They did this despite the fact that emperor penguins go without feeding for as much as four months during the winter. They stand with their feet tipped up so that only their heels touch the cold ice. A heat-exchange system in their nostrils, a variation of the rete mirabile seen in the blubber of a whale, captures eighty percent of the heat that would otherwise be lost with each exhalation. As many as six thousand of them huddle through the winter in single groups, conserving heat, each bird leaning slightly forward, maintaining pressure on the one in front of it, creating in the end a circulating mass of penguins so that no one animal is stuck on the outside long enough to freeze. Eventually, under the care of the males, chicks hatch. A penguin chick is naked, unfeathered from the neck down, so it spends its first days standing on its father’s feet, tucked into a brood pouch at the base of the father’s rather portly belly. Although a sixty-mile hike almost killed Cherry-Ga
rrard and his companions, and likely would have killed almost any other humans who had attempted it with the equipment available to these men, the penguins stand around incubating eggs and raising their young without feeding for months on end before marching fifty or sixty miles back to the sea, where they will end their four-month fast by plunging into ice-cold water and chasing down crustaceans and fish.
Nearly two hundred thousand emperor penguins live in Antarctica. They are, arguably, the most remarkable of the winter-active birds, but they are hardly the only winter-active birds. Redpolls, ravens, chickadees, ptarmigans, and a host of others prefer the risks of cold to the risks of migration. Of birds that overwinter in the cold, only the poorwill is known to enter into a state of long-term hibernation. The others have various tricks to survive the cold. The ptarmigan, best described as a snow chicken, a near cousin of the prairie grouse, has feathers that cover its feet and toes. In winter, when it has to digest fibrous twigs and bark, its gut lengthens. It hunkers down in the snow, only to flush out suddenly, flying low, landing not too far away, white feathers disappearing into white background. It goes beyond hunkering, knowing how to avoid wind by tunneling into snow, forming a cave near the top of a curving passage that traps its body heat. It hides out with the lemmings and voles and bugs beneath the snow, but unlike these subniveans, it uses its tunnels intermittently. It comes out to feed or, like the raven, to take a snow bath, throwing snow into the air and rubbing it across its body.
A naturalist writing in 1900 described insulation found in a cross-bill’s nest, saying that the nest was lined with “long black tendrils resembling horse hair.” Another, writing nine years later, described the insulation as “wool and moss” and “rabbit fur.”
Other birds shiver through the winter. Shivering, though, requires calories. A chickadee’s feeding rate increases twentyfold in winter. A crossbill needs to find a spruce seed every seven seconds. An emperor penguin might start the winter at eighty pounds and end it at a lean fifty, emaciated under its feathers.
It is the feathers that allow all of these birds to remain active through the winter. Without feathers, none of them would have a chance. Pennaceous feathers — feathers that can become quill pens — cover these birds. Feathery barbs extend from the central shaft of pennaceous feathers, and along these barbs are microscopic barbules and tiny hooks called barbicels. The barbicels lock one feather to the next, encasing it, superior to shingles covering a house. Dry beneath the pennaceous feathers, down feathers — fluffy feathers with no barbules, the kind of soft, tiny feathers that are used to stuff jackets and expensive sleeping bags — hold air and warmth. Even when the bird dives, the down, beneath the interlocking pennaceous feathers, remains dry.
If the pennaceous feathers leak, the down becomes wet and useless. A bird with leaking pennaceous feathers cools quickly. In oil spills, thousands of birds have found themselves swimming in crude. The oil makes their pennaceous feathers leak. They try for a time to maintain body heat by shivering, first in their pectoral muscles, where the wings attach, and then later in their leg muscles. Shivering burns stored calories. While they shiver, they preen, trying to scrape away the oil. When the stored calories are gone and they can shiver no more, they die of hypothermia. Or is it starvation?
It has been said that feathers evolved first to protect birds from the cold, and later the birds realized or learned or somehow found out that feathers, managed in just the right way, would allow the convenience of flight.
JANUARY
It is January fifth and twenty below at the edge of this frozen North Slope lake. I call it a lake, but really it is a flooded gravel pit dug into an oxbow, a long-abandoned river channel, to provide gravel for the more than four hundred miles of roads that crisscross the Alaskan oil fields. It is eleven in the morning, and what passes for dawn is upon us, which, at this latitude and this time of year, means the sky is subtly lightening in the east. An almost full moon shines through ice fog, along with the bright lights of industrial facilities in the distance and the headlights of an idling truck. The truck’s lights send beams out onto the lake, bisecting wind-sculpted snow on top of ice and capturing tiny suspended crystals of ice fog. Everywhere, the snow on the ground and the fog above it reflect the lights, snuffing out shadows and muffling any sense of contrast, the end effect disorienting.
We are lucky. Yesterday it was forty below and the day before even colder, the temperature as brutal as a physical assault, making one gasp for air but then forcing a stop mid-gasp as cold air batters warm lungs. The difference between forty below and twenty below is striking. Today, at twenty below zero, it is cold enough only to ice up one’s eyelids and freeze the inside of one’s nose.
We walk out onto the lake. The snow screeches under our boots, as if we are walking on Styrofoam while wearing Styrofoam boots. It is so cold and dry that our boots kick up little clouds of snow that the breeze carries along the surface of the lake, like dust clouds one might kick up on a desert sand flat. Fox tracks cover the lake, zigzagging from one side to the other, looping around on themselves. There are rabid foxes in the area. Just a week ago, a fox ran repeatedly out onto a gravel road, attacking anything that moved, including trucks. When the fox attacked a front-end loader, it lost, and its crushed carcass, sent to a state laboratory, tested positive for rabies.
I am with a team of hydrologists. They want to understand how water chemistry changes through the year, and especially in winter, when lakes are hidden by snow-covered ice. They want me to understand what they are doing and the difficulties they face. They drag two sleds onto the lake. A woman carries shovels and a gasoline-powered drill, and another woman holds a tent of the kind used by whiskey-sipping ice fishermen in Minnesota. The hydrologists shovel snow from the lake’s surface, pull-start the drill motor, and bore down into the ice. Though the snow dampens it, the noise of the two-cycle engine fills the cold air. In less than a minute, the drill cuts in a foot, two feet, three feet, and then water gushes up and spills out across the surface of the ice, turning immediately to slush and within seconds forming clear ripples of new ice across the older translucent ice of the lake’s surface. The hydrologists erect the tent over the hole. Inside, they light a small heater. The heater’s immediate impact on the warmth of the tent is comparable to what one would expect from a birthday candle. It is so cold in the tent that slush forms continuously in the hole. They scoop the slush from the top of the hole and lower an instrument thirty feet into the water. They measure temperature, pH, conductivity, and dissolved oxygen. The heater glows in the corner of the tent, but it is pathetically underpowered and effectively heatless, providing only a soft red glow and offering nothing more than ambiance as one hydrologist reads off data and the other sits on a box taking notes.
It is oxygen that interests the team most. There are fish in this lake, grayling that swam in from the adjacent river during high water. They overwinter in these deep lakes, these flooded gravel pits, where they find water that will not freeze solid by spring. This lake will not freeze solid. In all likelihood, the ice will grow six feet thick — somewhat thicker than most hydrologists are tall. Below the ice is fifty feet of liquid habitat. But the ice seals the surface. Whatever oxygen was in this lake when it froze is all the oxygen these fish will share until spring. At the bottom of the lake, oxygen-hungry bacteria work the sediments, decomposing anything that has fallen down from above. The bacteria compete with the fish for oxygen, sucking it out of the depths.
“These lakes,” the hydrologist tells me, “provide water for industry.” The water in these gravel pit lakes is used for drilling and for washing trucks. It is used for building temporary roads of ice that reach out across the tundra to winter construction projects. It is even used for drinking and bathing. The fish are kind enough to give up millions of gallons each year, to share it with the oil industry. The water level of this lake will drop five feet before spring, those five feet hauled away ten thousand gallons at a time by big red tanker trucks. Even n
ow, as we talk, a truck sucks water from the lake. The driver sits in the cab, bored but warm, with a black hose running to a white pump house next to the lake and steamy exhaust from the truck blowing sideways, out over the lake, toward our little tent with its glowing, insignificant heater and its scientists armed with instruments and data sheets and thick gloves. Under all of this ice, the fish tread water, waiting for spring, their chilled brains probably incapable of even wondering what that funny pumping sound is that they hear now and again as these humans come and suck out five feet of swimming headroom.
Later, in the warmth of a dining hall, a man tells me that a worker has been attacked by a fox. It happened ten miles from our gravel pit lake. The fox ran out of the darkness and bit the man in the leg. The man tried to shake it off, as one might shake off a pit viper, but the fox hung on to the cuff of his snow pants. He kicked it. It lay in the snow as if dead but later got up and staggered off into the Arctic winter. Its rabid teeth, slowed down by the worker’s snow pants and stopped by his boots, never penetrated the man’s skin.
The world’s liquid freshwater resides in rivers and lakes, in underground aquifers, and in the sky. Eight-tenths of the world’s freshwater is frozen. Another three thousand trillion gallons drifts in the atmosphere. But to say that it drifts does not do it justice. The water cycles through, riding thermals, now as a vapor, now as a droplet, now as a speck of ice coalesced around a particle of dust nine miles high in the troposphere. It is now in the air as mist, now as rain within a cloud, now in the Pacific, now as a downpour falling on hot pavement in south Georgia, now on the northern pack ice. It might rise up from the equator, sink down as a driving rain in the horse latitudes, drift for a while in the Gulf Stream. Rising again to travel farther north, it eventually makes its way poleward and falls as snow, then melts, running off into the North Atlantic to follow currents carrying it downward, finding its way to an upwelling, then drifting on the surface until it evaporates once more, only to wind up God knows where. In geological time, water molecules have been grand travelers, each finding its way everywhere, touching down everyplace, like irrepressible tourists on a four-and-a-half-billion-year junket.
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