McMurdo Dry Valleys are located within Victoria Land on the western coast of McMurdo Sound, Antarctica. These are the largest ice-free row of valleys that have extremely low humidity and lack of snow. These frigid valleys are an arid expanse of mostly dirt, small rocks, and big boulders. It is spread over an area of approximately 4,800 square kilometres. McMurdo Dry Valleys were first discovered by Captain Robert Scott in 1903, while he was on an expedition along with two companions. He and his crew considered that these valleys are void of any life and called it ‘a valley of death’.
Dry Valleys of Antarctica are unique with their frozen lakes and extensive areas of exposed soil. This is the region of the Earth that hardly has anything to support human life. However, a large variety of aquatic ecosystems thrive even in such harsh climatic conditions due to glacier melt-streams that flow into the ice-covered lakes. According to the researchers, Dry Valleys are home to different organisms that live in extreme environments, such as lichen and mosses, various kinds of microbes including cyanobacteria, microscopic worms, and nematodes.
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Cyanobacteria have the ability to kick-start the photosynthesis process within 48 hours of receiving liquid water, despite being in a virtually freeze-dried state.
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Research on the survival of these organisms and their adaptations under such harsh environment is still on.
Salty Water Aquifer
Researchers have recently discovered a salty aquifer beneath these valleys that could potentially support previously unknown microbial ecosystems. The study says that brines or salty water form aquifers below the Dry Valley glaciers and lakes, within its frozen soil.
The region of Dry Valleys is different from the rest of Antarctica because it lies in the mile-high Transantarctic Mountains (TAM). As these valleys lie in between the mountains which serve as a barrier from the East Antarctic Ice Sheet, they have their own brand of fierce weather, with temperatures dropping to as low as 90 °F or –68 °C. The air is extremely dry with Katabatic winds blowing at speeds as high as 200 miles (about 322 km) per hour. These winds mix with the gritty groundcover to sculpt rocks into smooth, odd-shaped formations called ventifacts.
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Katabatic winds, also known as drainage winds, carry high-density air from high elevations, like icesheets of Antarctica and Greenland, down the slopes under the gravitational pull.
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The McMurdo Dry Valleys Long-Term Ecological Research (LTER) project is an interdisciplinary study of the Dry Valleys’ aquatic and terrestrial ecosystems. As these valleys are located in a region, where ‘life approaches its environmental limits,’ they were selected, in 1992, for the National Science Foundation’s LTER Programme. Research has shown that the Dry Valleys offer scientists more than a laboratory for studying the Earth. These valleys are the Earth’s closest equivalent to Mars as they both have polar caps, valleys, rivers, lakes, and the coldest temperatures.
As per the LTER research data, Dry Valleys are very sensitive and have small variations in solar radiation and temperature. Unlike the Antarctica ice sheets that take many years to respond to any climatic change, the streams and ice-covered lakes of these valleys are very vulnerable and respond to any type of climate change almost immediately. This makes them the ideal place to study the first effects of climate change in Antarctica, due to human activities or otherwise.
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