Running on Tundra

Each summer a herd of scientists races north, enduring white nights and relentless mosquitoes to study one of the world's harshest ecosystems.

By David Berreby|Saturday, June 01, 1996
RELATED TAGS: ARCTIC & ANTARCTIC
Somebody had a bad day, Neil Bettez calls over his shoulder. Huffing and puffing under my backpack ten paces behind him, I can see what’s at his feet: bleached, broken bones, strewn in a rough circle on the mosses and grasses of the tundra we’ve been crossing. I pick up an L-shaped chalk-colored thing, about the size of a small hammer. Half a caribou jaw. Green swirls eddy along the tops of the big molars. At the snout end, there’s a row of tiny white front teeth, like a toddler’s. The rest of the jaw has been snapped away like a wishbone.

For the past six summers Bettez has hiked over this turf, working as an assistant to the ecologists based at the ramshackle camp a mile or so behind us, across a half mile of rolling hills, on the other side of black Toolik Lake. Piles of bones are everywhere here, left by wolf, bear, eagle, wolverine. Sometimes you see a whole haunch, still covered in blankety hair.

Bettez and Gretchen Gettel, another research assistant, are leading me up a gentle hill swathed in green mosses, sedges, and heathers and sprinkled with crinkly yellow and white lichens. Out of the green background sticks here a tiny yellow poppy, there a stalky purple fireweed, there a bright green horsetail that looks like an eight-inch Christmas tree. It’s a dense miniature forest that comes up only to our ankles. Drop us 20 miles in any direction--or even 200 miles to the east or the west-- and it would look exactly the same. From a helicopter this landscape looks like the ocean, frozen in a moment of swell and surf, rolling up to the mountains of the Brooks Range 20 miles to the south.

I put the jaw in my back pocket and brush 70 or 80 mosquitoes off my right arm. It’s a futile gesture. Every step you take on tundra kicks up a new batch, as thick as a snow flurry. My sweatshirt sleeve is covered again with them, tap-tapping their canelike proboscises, prospecting for blood. Back at camp, the official mosquito measure is the swat test--how many mosquitoes come up dead after you slap a flat palm down on an infested shoulder or thigh. This summer set a new record: 270. Even wearing head nets all the time, we’ve all swallowed a few.

Bettez and Gettel are standing on a hillock, feigning patience as I straggle up. It looks so easy to walk on, Bettez says. He talks like a stand-up comic, in bursts. Like a big green rolling lawn! But the spongy vegetation absorbs our steps and bounces us back like a trampoline, and as we go springing down the slope, we keep bumping our ankles against head- size tussocks. Stepping on a tussock is like stepping on a toothbrush, Toolik scientists like to say. You try to avoid it. So tundra walking is like treading on the jostling shoulders of a million people, trying not to kick anyone in the head. Every few feet the earth is saturated with water, and our feet sink an inch or two or six into a cold, tiny swamp. That’s why we’ve seen moose and caribou and foxes on Dalton Highway, the gravel-paved haul road that parallels the Alaska pipeline from Fairbanks to Prudhoe Bay. They don’t seem to like walking over tundra any more than the rest of us do.

There are roughly 5 million square miles of Arctic tundra, stretching across the brow of the world over Alaska, Canada, Greenland, Scandinavia, and Siberia (the equivalent terrain in Antarctica wears a permanent mantle of ice). Plenty of the world’s tundra has been studied, but one particular patch--100 square miles along the Kuparuk River, stretching from the Brooks Range to the flat plain by the sea--has been studied intensively. It has been carefully monitored since 1975, when John Hobbie of the Marine Biological Laboratories in Woods Hole, Massachusetts, and a few other ecologists took over an abandoned camp that once housed pipeline workers.

For the past 20 years researchers here have been assembling a portrait of an ecosystem, piece by piece, sample by sample. It is the simplicity of the tundra that draws them--the term comes from a Finnish word for barren, rolling plain. Not much can survive here, and what does survive has to withstand the winter’s cold and darkness. Those simple conditions make it the perfect place to elucidate how water and land, plant and animal, interact.

Here we can see the forest for the trees, says Gaius Shaver, a plant biologist from Woods Hole. There are ten species that account for 90 percent of the plant biomass. We can stretch a greenhouse over a small patch and sample the entire system for $200 worth of wood and plastic. We couldn’t stretch a greenhouse over a forest--or if we could, it would cost a fortune.

One of the most obvious constraints for plants and animals living on tundra is the abundance of water. People talk about wetlands--the Arctic is the biggest wetland of all, says George Kling, a water chemist from the University of Michigan. Fourteen percent of the entire land system is covered by water.

Collecting samples in a shallow tundra pond, you literally bump up against the reason for all the standing water: after a few steps over loose brown sediments, you abruptly sink to your hip and feel your foot hit against a smooth, steel-hard surface. You can feel the chill through your waders. This is permafrost--permanently frozen ground, as hard as concrete and more impermeable. The unfrozen ground that sustains all tundra plants and animals is only a half foot to three feet deep. Under that, Kling explains, it’s permafrost for hundreds of feet down. You can slide on it. It feels just like a skating rink.

Once exposed, permafrost will melt like wax, sinking whatever lies on it and occasionally exposing a mammoth tusk or another relic of an ice age. Dalton Highway, in fact, rests on a layer of fiberglass insulation. But when protected by the unfrozen topsoil, permafrost is an absolute barrier, so impenetrable that in summer, meltwater saturates the ground; if the water can’t course on to a stream or lake, it just stays put.

What creates permafrost, of course, are the long, cold winters. Here, 150 miles south of the Arctic Ocean, winter lasts ten months, and for three of those months the sun never rises. Then, from late May to August, the sun doesn’t set at all, moving around the horizon in a low, tilted circle. Around June the snow melts, rivers flood, and lake ice breaks into columns that bump up against one another with a beautiful chiming sound before vanishing to reveal water nearly black with the granulated remains of long-dead plants and animals.

At breakup, says Kling, the gurgling three-yard-wide stream that feeds Toolik Lake roars like a waterfall. It’ll be going by at three meters a second, and it’ll have huge blocks of ice and trees and other things in it. And the lake is all covered with ice, so you see these things go by and then bam, they hit the lake ice and just shoot right under it. The rush of water and sun brings fish up from the unfrozen depths of large lakes, birds from the south, and various land animals, like moose, up from the forests or out of hibernation. The caribou herds, in the hundreds of thousands, give birth all at once, when the new spring shoots are most nutritious. All summer, life races against a clock, gathering strength for the cold that comes in August.

Even for plants, food is hard to come by. The bacteria that break down dead plant matter--and thus free up the nitrogen that living plants need for photosynthesis--work very slowly in the cold. So dead plant matter accumulates on top of the permafrost as a layer of nutrient-poor peat--a crumbly brown cake of acidic organic carbon. Moreover, because cold temperatures slow the chemical reactions in photosynthesis, all plant growth has to occur in high summer, after temperatures have warmed up.

Growth is dicey in summer too. Summer temperatures on Arctic tundra can reach 90 degrees--or it can snow. Given these constraints, tundra plants would be stumpy even if they could get their roots into rich soil. So, during the brief reprieve from the bitter cold, they concentrate on making roots and leaves, not weight-bearing fibers like trunks and branches. It is easy to see why some of the most common species are those that literally feed on air. These organisms--lichens on land, and algae in the lakes--absorb nitrogen from the air and convert it to fertilizing chemicals like nitrates or ammonia.

With food and time so short, there’s little room for bad luck. Just a few more inches of snow, for example, can have a big effect. When the snow is less than 8 inches deep, light will penetrate enough to warm the ground, causing the snow layer to melt at both the top and the bottom. But in 1993, for example, snowfall was 11 inches (nothing unusual; Arctic weather varies a lot). Snow that deep is warmed only at the surface, and thus takes three times as long to melt. The delayed thaw disrupted the breeding of white-crowned sparrows, says John Wingfield, a University of Washington ornithologist who has spent the last seven summers at Toolik Lake.

Since the breeding season is so short, they can’t afford to wait a couple of weeks for the snow to melt, Wingfield says. That’s why many Arctic birds are unterritorial. We’ll band 50 white-crowned sparrows and never see them again. They’re niche opportunists. They’ll go far away, where conditions are right.

Like a good niche opportunist myself, I’ve snagged a seat on a helicopter trip with George Kling to study lake chemistry at 15 sites. John O’Brien, a biologist from the University of Kansas, is coming, too, along with Bettez. The trip will allow them to sample lakes and rivers they could never reach on foot without destroying the fragile tundra. (The vegetation is so delicate that Caterpillar tractor treads over winter snow leave marks on the plants below that can be seen 20 years later.)

As we come roaring and clattering out of the sky, flattening the gray ripples of Lake Itkillik and the green grasses and sedges with our downdraft, we scare the bejesus out of a golden plover with a nest nearby. When we get out and tromp around, she doesn’t flee. She plants herself next to a tussock and pipes a high, shrill, hollow note. One trembling gray, speckled wing droops, half open, away from her black-bellied body over some pale yellow lichens. Her eye, behind a thin, wide-open beak, is fixed on us, looking to see if we believe her act: Here I am with a broken wing, an easy catch. Never mind the chicks. Come after me. On the bright, bare tundra, with nowhere to hide, parents head toward danger.

She’s still piping as Kling, Bettez, O’Brien, and I head for the lake’s gravelly banks. Tom Husted, the pilot, stays behind, wiping the corpses of hundreds of thousands of mosquitoes off his fuselage. The water samples Kling and Bettez are taking will be broken down chemically to yield a precise reading of the carbon content of the water. In a recent series of experiments, Kling has found that tundra lakes near Toolik do a puzzling thing: they give off carbon dioxide. Usually lakes are carbon storehouses; it settles in a lake in the form of sediments--either dead algae or peat from spring runoff.

The reason the lakes breathe carbon dioxide, Kling explains, is that as the weather warms, bacteria break down dead plants, which releases carbon dioxide into the soggy earth. Spring runoff will sweep this carbon dioxide into the lakes, eventually so saturating the water that the carbon dioxide is released into the air. Kling now wants to see if it’s a tundra- wide phenomenon. He suspects, in fact, that it happens in temperate lakes as well but that the effect is masked in more complex ecosystems.

O’Brien is after water fleas, testing a theory about how three species can coexist here. He wades hip deep into the concrete-colored waters carrying a long rope fastened to a funnel made of fine netting, with a metal cup at its narrow end. Reaching back like a discus thrower, he casts his net in an arc over the waves. It lands with a soft plish, and he reels it in, looping the rope around his elbow.

Across the lake, maybe 200 yards away, I can see six white birds gliding in long parabolas over the lake. One flies by, undulating a little with each leisurely wing beat like a wooden duck on a string, its tiny eye on us. It looks like a little seagull with a black skullcap and a swallow’s V for a tail. Now, that’s an Arctic tern, says O’Brien, looking up from the water. They live all their lives at sea near Antarctica. They only come ashore when they come up here in the summer to mate.

After one pass over us, the tern decides to go back to work. Sunlight fills its mother-of-pearl wings as it banks, heading away toward the far side of the lake. Suddenly it stops in midair and shrug-shrug- shrugs its wings to hold position with its back arched toward us, as if it were rowing an imaginary boat our way. Then it plunges like a rock. One surprised fish has just joined the food chain. The terns have only eight weeks to mate and fledge chicks strong enough to fly 11,000 miles south. Time is short. You do what you can.

Cutting across the rolling wilderness, the Alaska pipeline runs from Prudhoe Bay over the tundra, over the Brooks Range, through the forests to the year-round port of Valdez on the state’s southern coast. It is 800 miles of 48-inch-wide steel gray pipe resting on dark orange steel pylons (on most, it rests like an object on a shelf, unattached, so it can play free in earthquakes). The pipeline zigs and zags irregularly over the rolling tundra, occasionally bending upward as if a giant hand were raising it so caribou could pass underneath. In some stretches, where the soil is not frozen, the line dives underground. Above it, there are little yellow signs warning: PETROLEUM PIPELINE. DO NOT DIG.

Mostly, though, the line floats lightly above ground for hundreds of miles through total wilderness. Just as the oil companies that built it would like you to believe, moose, caribou, and bears easily coexist with the pipeline. Even the ecologists here give it grudging respect. They really did it right, says O’Brien.

Toolik Camp has inherited the pipeliner’s claim on the land. The jumble of white tents and gray-green trailers beside Toolik Lake looks like a cross between a fishing-lodge area and a MASH unit. With 70 people sharing tents and trailers, the place gets very cramped. There are no flush toilets and only one shower. The preferred method of bathing begins with a long sit in the sauna the scientists have built by the lake, followed by a rinse with a bucket of water and a jump into the chilly black waters of the lake. Mosquitoes cure you of any hesitation to dive.

Another Toolik Lake visitor is the Arctic ground squirrel. Its scientific name is Spermophilus parryii, but the Inuit people of Alaska have a friendlier name: they call it the siksik, in imitation of its loud alarm call. Richard Smith, a biochemist from the University of Alaska at Fairbanks who runs the water-sample analyzer, got acquainted with one bold siksik when it repeatedly invaded his trailer to steal his office mate’s Snickers bars. By the end of the last field season, he looked like a Vienna sausage with feet, says Smith.

Siksiks gorge themselves in the short summer to prepare for hibernating in the long, bitter winter. Because of permafrost, they can’t dig deep. And digging burrows beneath a thick, insulating blanket of snow can be treacherous--unless the soil is well drained, they will drown during spring runoff. So they’re often forced into exceptionally cold underground burrows.

Brian Barnes, a physiologist from the University of Alaska at Fairbanks, is studying the siksik’s extraordinary knack for resisting cold. Siksiks hibernate alone from September to April, and their body temperature actually drops below freezing. Yet siksiks don’t freeze solid and die. Instead, they chill down gently, reaching a supercool state in which their bodily fluids, though colder than their normal freezing point, remain liquid.

This is common enough for clouds and ice-cube trays in freezers that have cooled gently, but it’s extremely rare among mammals--and surprising, because liquids that have become supercool are highly susceptible to freezing. If supercool water contains a single sliver of ice or a speck of dust, it will instantly crystallize, just as frozen water in a cloud crystallizes into ice around a speck of dust. Somehow, says Barnes, siksiks have developed a defense against such potential nucleators, cleansing them out of their blood before hibernation begins. Understanding how they do so may lead to improved preservation of transplant organs.

At the moment, though, most grant money for tundra research relates to global warming. The Arctic is expected to warm considerably more than the rest of the world, but the effects of that on plant and animal life are far from clear. For example, although Toolik Lake is now about 5 degrees warmer than it was 20 years ago, the increase hasn’t stimulated plant or animal growth in the lake. One possible explanation is that warmer temperatures may cause melt-off from the mountains and tundra to arrive too early, before the lake ice has melted. If that happens, all the peat particles that would normally flow into the lake and supply algae with nutrients like carbon and phosphorus may flow onward, bypassing the still- frozen lake.

Any Toolik researcher can explain with great earnestness why his or her work will bear on global concerns. That’s what brings in the grant money, and helicopters, at $607 an hour, aren’t cheap. But when the longtime Toolikers relax, John Hobbie will talk of looking through a telescope in spring and watching a wolverine tobogganing down a snow slope, zooming teeth-first through a plume of icy crystals, for the fun of it. O’Brien will talk about No-Doz, a curious grizzly that kept the camp up for several long white nights. What really brings these men and women back every summer is love for the place. They’re tundra patriots. I first went up in 1989, in April, says John Wingfield. And it was just astonishingly beautiful. It gets in your blood. I tell my graduate students, ‘Maybe you couldn’t stand the mosquitoes and you think you’ll never want to go back, but you will.’
Comment on this article
ADVERTISEMENT

Discover's Newsletter

Sign up to get the latest science news delivered weekly right to your inbox!

ADVERTISEMENT
ADVERTISEMENT
Collapse bottom bar
DSC-JanFeb15
+

Log in to your account

X
Email address:
Password:
Remember me
Forgot your password?
No problem. Click here to have it emailed to you.

Not registered yet?

Register now for FREE. It takes only a few seconds to complete. Register now »