Life in the Deep Freeze: But for How Long?
This month, quests for clues concerning the origins of life continue as experts start exploring the possibility of life forms surviving in an extreme location – Antarctica. Expeditions like these are vital for not only scientific advancement, they also demonstrate the tolerance and fragility of the natural world – and our place within it. These are valuable lessons that are worthy of a reminder, especially as we anticipate an age of unknown environmental changes, which have the potential to affect all of us.
Encompassing the South Pole, modern-day Antarctica is encased in ice and experiences temperatures as low as -89oC. In spite of this, up until the Jurassic period, some 170 million years ago, Antarctica was part of the super continent Gondwana, which spanned what is now South America, Africa, Arabia, India, New Guinea, and Australia. During the heyday of the dinosaurs, this immense landmass started dismantling, and by around 25 million years ago, tectonic motions heaved Antarctica to its current position at the base of the earth.
Even with its current climate, Antarctic fossil finds indicate ecosystems that once supported trees, amphibians, and reptiles. As the continent edged south, though, ice soon encroached across the land, freezing any indigenous flora and fauna. Today, Antarctic seas support seasonal plankton blooms, invertebrates, fish, and whales, while penguins and seals colonize the coast. Inland Antarctica is mostly devoid of life, although polar algae and lichens encrust exposed rocks. New studies, however, indicate that ancient lakes, entombed in ice, may support primeval microbe communities, isolated from the rest of the world in their own microcosm. Even so, these communities may soon struggle to survive even here if the chemistry of the atmosphere continues to change.
It is counter-intuitive to think lakes exist under deep pack ice. This was the prevailing thought until scientists in the 1950s and 1970s used seismic waves and radar to examine the terrain deep below the ice. Remarkably, the results revealed that lakes do exist; the immense thickness of the ice acts as an insulator from the frigid atmosphere, while geothermal activity below heats lower aquatic layers, preventing freezing. It is not yet known whether these unique conditions – occurring in 387 sub-glacial lakes – harbor life, which is why pioneering expeditions are now being conducted by the British to reveal the limits of life and its origins.
Concealed by the West Antarctic Ice Sheet, Lake Ellsworth now provides the site for deep-field research. Using hot-water drilling, scientists are preparing to bore a 3-kilometre hole into the ice, through which a titanium probe will descend to sample water and sediment. The outcomes of this operation could revolutionize our knowledge of how life developed over geological time, how organisms tolerate extreme conditions, and even how life on other planets could exist.
Scientists expect to find an assemblage of microorganisms, including viruses, bacteria, and more advanced eukaryotes, which possess a nucleus. Inhabiting a lake, which was sealed off from the rest of the world many thousands of years ago, these organisms would have undoubtedly adapted and evolved to suit their environment. Developing in isolation, the genetic and physiological traits of these life forms and their lineages could shed light on their evolutionary progression. Even if no organisms are discovered, the results will be of equal importance, for they will demonstrate a limit to the extremes that life of earth can endure.
With today's technology, it is vital that scientific advancements continue and that we support and fund expeditions to hostile regions and learn about our most distant pasts. With a cost of $11 million, this is not a cheap venture, and there are concerns that penetrating the lake may contaminate this pristine environment. Even so, the popularity of documentaries such as the BBC’s Life in the Freezer and this year's Frozen Planet demonstrate a fascination in polar research among the public.
Today, it is necessary to study the poles – areas prone to change due to predicted shifts in global climate. If we fail to further this understanding now, it might not be possible in the near future. It is also important for humanity that we explore these last unknown geographies, for discoveries of organisms in such extremes demonstrates not only the zeal and zest of life, but also indicates life’s vulnerability in a rapidly changing world. Exposing the ice lake to the atmosphere may be lethal to the microbes within, just as polluting the sea and air is lethal to more familiar species, including ourselves. If life is found, surely it will be an eye-opener for all of us in this finely balanced, ever changing world.
Photo Credit: John E. Lester