Michael Becker, a doctoral student at McGill University, was a scientific diver on an expedition to Lake Untersee in Antarctica.
The hills around here are quiet. On windless evenings nothing seems to stir, and indeed there is not much to do besides listen. Aside from the occasional crack and rumble of a shifting glacier, the echoing snap of the frozen lake, there is a distinct lifelessness to the place.
Surrounded by looming peaks and ice around us, you would get the impression that this place is stationary in time ? or at least vastly slowed. Time creeps by as if ticking in centuries instead of seconds. There are no sounds of machines, no sounds of swaying trees, no crickets. It feels empty.
In the seemingly lifeless surroundings of Lake Untersee, there is still life to be found if you know where to look for it.
It is in these silent hills that a member of our team, Dr. Alfonso Davila, goes in search of hidden organisms that make their home under the rocks. Photosynthetic cyanobacteria survive this hostile environment by using the rocks around the lake as shelter. These are known as either hypoliths or endoliths, depending on whether they?re found under or inside of rocks.
But the rocks around Lake Untersee are relatively nonporous ? and so the area seems to favor the hypolithic life strategy as we have found cyanobacteria living primarily under clear translucent rocks such as quartz. The rocks also create small, bowl-shaped depressions in the sand. These depressions allow moisture to collect under the rock, providing vital water to the hypolithic microbial communities in a polar desert.
Dr. Davila is studying these microbes to describe possible survival strategies for life on other planets, a science known as astrobiology. The work here, and in other harsh environments, clues us in on possible, less obvious places where life might persist in the face of adversity. The information gleaned will go on to inform the search for life on other planets, and help us choose where to look for life on places like Mars.
But it?s not only the microscopic that manages to hang on here. Some larger creatures also even prefer it for the protection from predators that the seclusion that the polar desert offers. On one of my few days off I went in search of one area?s most enigmatic residents: the snow petrel.
The reclusive birds nest high in the hills around us. They are tricky to get to, and take a fair amount of commitment to approach.
I decided to walk toward one of the cliffs around camp to catch a glimpse of these birds up close. A walk that appears to take 10 minutes takes closer to an hour as there are no buildings or trees for visual scale to accurately judge distance. What looked like gravel slopes from afar turned out to be a field of boulders the size of cars. On my approach to the slope, those small white dots slowly grew bigger until it was clear that snow petrels were pouring out of the hills.
One of the most incredible things about these birds is that they never seem to land. They seem to have no need for their legs as they flit about constantly in the air ? diving, swishing and swooping right against the rock face with near total disregard to their longevity. As I approached the hills they got curious and started circling overhead, not much farther than 50 feet away. Ghosts of a bird, they are pure white and never seem to make any sounds other than the startling ?swoosh? as they speed past. I?ve sat around their colony for hours, with only the rarest cackle emanating from deep within the boulder field. For a colony of thousands this is extraordinarily quiet.
Snow Petrels are an entirely Antarctic bird, being one of only three bird species in the world to breed exclusively in Antarctic areas. This lifestyle has required them to evolve unique adaptations to cope with the environment?s harshness. They are one of the few types of birds to have tubenoses ? a hard, hollow structure above their bill.? Because it?s generally frozen, fresh water is a scarce commodity in the Antarctic and so petrels must be able to drink salty seawater without harm. A specialized gland at the base of the bill helps regulate blood salt content by concentrating excess salt into a liquid that then drips out the tubenose.
During the winter months snow petrels fly north to the edge of the sea ice and while away their time next to the open ocean. During the summer months they fly south inland to these few rocky oases to breed. They have been following this pattern for millenniums, and their mark on the landscape is tangible. The land around here is littered with the twisted and disfigured bodies of dead snow petrels that have expired after breeding. Push over a 100-pound boulder and you?re likely to find feathers underneath. Look between cracks in the rock and you?re likely to find any odd assortment of legs, beaks, skulls, wings, rib cages.
As you approach the cliffs where they breed, the bodies become more numerous until it becomes such a critical bulk that I would dub some areas? ?mass graves.? Interestingly, there seem to be two types of these: the first (lower on the hill slope) are neatly ordered rings of bodies and petrel parts, a clear patch of sand with bird remains strewn about. These are skua kill sites. Skuas are the only other bird in the area, and they are predatory. These large, aggressive, dark brown, gull-shaped birds are the vultures of the Antarctic, as they?re known to go after live birds, carrion, and even garbage.
The food chain is a simple one: skuas eat snow petrels. Skuas will prey on young or weaker birds, pick apart the body and toss the bones. These meter-wide kill sites have a predictable pattern of destruction about them.
The other type of mass grave is like nothing I?ve ever seen before. They can be found in protected areas of the cliffs where the petrels breed. But instead of the tattered remains of skua attacks, these dead birds are nearly whole. It seems as if the adult birds raised their offspring, and because of age or exhaustion, succumbed and died on the spot. These nesting sites are used year after year. As it?s too cold here for their bodies to rot, and too narrow for the skuas to get to, the years go on and the bodies pile up. Looking down these cracks I?ve seen stacks of bodies nearly three feet deep.
It?s hard to estimate how large the colony here is. Aside from the neurotic frequency of flying, it?s also impossible to access most of the prime nesting areas. The cliffs here are steep and the scree slopes unstable. At over 60 degree inclines, these hills are landslides waiting to happen, making it near impossible to even safely reach the base of most rocky outcroppings around. As a hiker with that ever-incessant urge for that higher view, this is torturous. Indeed, I?ve never been more jealous of a bird?s ability to fly. The cliffs here are all but inaccessible to me and I gaze wistfully at ridges I?d like to walk, hanging valleys thousands of feet above, cliffs hiding other cliffs ? a whole world out of my reach.
Follow Michael Becker on Twitter: @Michael__Becker or on his blog, ?The Dry Valleys.?
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