You won’t find many roads in Antarctica and those you do find don’t go far. If you need to get someplace on land, you’ll be going by air and if where you’re going doesn’t have a runway, you’ll need a helicopter. McMurdo Station keeps a fleet of helicopters operating almost full time during the summer months. They are particularly useful here because scientists are the kind of folks who want to go places that are hard to get to and where hardly anyone else would want to go, such as the Dry Valleys of Antarctica or far out on the ice. The scientists typically set up a camp at remote sites consisting of a few tents and sometimes a lab module—a small prefabricated structure that can be flown in by helicopter—if you can prove you warrant one.
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Helicopters deliver the scientific teams to their sites and provide them with supplies that will last for the period of the work, often weeks or a month or two. Field work of necessity is intense, focused on an all-out effort to get as much done as possible in the short summer, record the data and take specimens for subsequent analysis in the more substantial labs found at McMurdo. It takes a special kind of person to make this kind of effort given that the “pay” for the work is essentially only the excitement of discovery.
Today we have the opportunity to visit field sites in one of the McMurdo helicopters, and we have another beautiful day for this trip. There is hardly a cloud in the sky and the temperatures hover around freezing, positively balmy for this clime. You can see forever in these conditions and the view never fails to inspire awe.
At 8 a.m., we arrive at the heliport where helicopters are already taking off for different locations. We are briefed on helicopter safety and given a helmet with a cord to plug into the helicopter’s voice system. We are weighed with all of our gear to make sure our cumulative weight will not create an overload. Fortunately, we pass the test and we board our helicopter. Because there are only five of us (not including the pilot and co-pilot)—Kristina Johnson, Steve Koonin, Tom Peterson, me and Dr. Alex Isern, an National Science Foundation employee program officer in the office of polar programs—we all get window views. Alex proves be adept in helping us understand the ways of the helicopter as well as being knowledgeable about all of the science we will see.
This morning our trip will focus on the famous Dry Valleys of the Antarctic, the driest places on earth. The only other places comparable to them are thought to exist on other planets, such as Mars. The Dry Valleys of Antarctica receive only the barest precipitation, and as best as can be determined, have seen no measurable precipitation for more than 2 million years. That’s a right pert dry spell by anybody’s calculation.
That is not to say that there is no water or moisture in the Dry Valleys because they do have massive valley floor glaciers as well as alpine glaciers that spill down the valley walls attempting to reach the valley floor. The valley glaciers move at a “glacial pace” of truly epic slowness toward the sea, not by virtue of snowfall in the valleys themselves, but because of small annual snowfalls up in the mountain peaks that are the glaciers’ source.
The “hanging glaciers” on the valley walls more often than not cannot ever reach the floor of the valley because the annual snow falls in the mountains that drive them are so small the glacial front reaches an equilibrium point where its ice front sublimates, or passes from solid directly to water vapor, as fast as the front tries to advance. Still, on a few rare warm summer days some of the ice of the valley glaciers and hanging glaciers does melt. Scientists call this melting a “pulse” because it occurs infrequently and for a short period of time. The pulse water flows into lakes that form in the valleys between the fronts of the valley glaciers. The flow into the lakes is so small and so much of the water evaporates during the summer that it gradually creates a salt lake, much like those you would find in a desert area.
As scientists learn more about these lakes they have found that the salinity is stratified with some depths more saline than others. The lakes range in depth from 25 to 40 feet, and are of great interest not only to biologists but also those who expect to find such features on the dry surfaces of planets that do not have as rich an atmosphere as the earth. NASA has even sent a submersible to these lakes to explore them at depth because it is believed if there are extraterrestrial lakes they might look just like those found in the Dry Valleys of Antarctica. Our helicopter lifts off around 9 a.m. and we take a flight path to the northwest across the sea ice of McMurdo Sound with sweeping views of Mount Erebus to the east and the snow-covered mountain ranges that contain the Dry Valleys. As if to emphasize that we are in the Antarctic, a group of large surprisingly rectilinear icebergs lounge at the boundary of sea and sea ice.
Our first stop takes us up Taylor Valley to Lake Hoare where a research team working with Diana Wall of Colorado State University is studying interactions between climate and other global changes on the abundance, diversity and distribution of soil biota. Looming like a massive white curtain wall across the east side of the valley floor is the 50-foot front of a glacier that has intruded itself just downstream of Lake Hoare after travelling down from a higher valley and making a sharp right turn into Lake Hoare where it appears like an uninvited guest. As we take a moment to look around, we are surprised to come upon the bodies of a penguin and a seal lying at the foot of the glacial front. Amazingly, these creatures had apparently made their way across the vast expanse of the glacier lying in the entrance to Taylor Valley only to fall over the precipice of the front. We are told these animals likely lost their way due to some failure of their natural navigation system and just kept going until their fate was sealed. In this arid and cold climate without the presence of scavengers, bodies mummify and remain for years. The Antarctic does not give mercy to those who make mistakes.
Lake Hoare lies in a valley surrounded by steep walls with exposed, bare rock showing sculpted scars created by the valley glaciers during the last period of glacial advance around 20,000 years ago. The valley walls exhibit faults and magmatic dikes that cut across the beds. These rocks are much older than the Antarctic continent itself, having been part of the ancient supercontinent Gondwana before it separated into today’s many parts. Standing in this spot you can see direct evidence for the power of nature and sense its patient processes: Tectonic plate movements that move continents and make mountains where none existed, winds that scour rocks and pulverize them, glaciers that silently move and strip bare rock walls, gravity that brings down big boulders so that the bounce like toys into the glaciers below, and freezing water that expands and cracks even the hardest rock. Humans have a difficult time appreciating all of this even though it is massive and constant because nature works on such a long time scale. We live on average 75 years and our species only goes back about 200,000 years, a blink in the eye of nature. Yet we are beginning to become something of a geologic force ourselves, because the cumulative impact of 7 billion of us on the planet is having an effect.