What lies beneath?

One doesn’t often think of Antarctica as a hive of activity. However, its isolation provides an opportunity for scientific research uninterrupted by human expansion; this week it was the centre of some ground-breaking research (pun intended!). Lake Vostok is one of the largest freshwater lakes in the world, but what makes it unique is its sheer inaccessibility – it lies 4,000 metres beneath the central ice sheet of Antarctica, untouched by life for more than 15 million years! Russian scientists have been drilling down to the lake’s surface for more than 14 years and last week they finally reached their destination. In case you didn’t know, and before we continue, Antarctica is the home of over 100 research centres from dozens of countries due to its vast opportunities for discovery.

What’s to discover in the ice you ask? Check out this picture: it shows a three-inch long shrimp-like creature, known as a Lyssianasid amphipod, found 600 feet beneath the West Antarctic ice sheet and 12.5 miles from open water. Scientists have argued that the extremely high levels of oxygen and nitrogen found in many of the lakes are toxic for most life forms – the water in Lake Vostok, for example, has a consistency similar to a fizzy drink! Nevertheless, multicellular organisms including the Lyssianasid amphipod call the ice-sheets home. The resilience of such microbial life forms has made scientists hopeful that ancient bacteria could have evolved to cope with the frozen, black conditions under the ice-sheet.

Another on-going research mission is the British expedition to Lake Ellsworth, which lies 3,000 metres under the West Antarctic ice sheet. The continent’s isolated nature, purity, and weather conditions (the coldest temperature ever recorded on Earth was minus 89° Celsius at Vostok) pose specific challenges for recovering samples. The expedition at Lake Ellsworth is therefore using “space-industry standard clean technology” to collect liquid water samples, including sterilised polyurethane bellows. The sterilised technology allows the researchers to enter the lake without danger of contaminating either the lake or the samples. Kevin Saw, who heads the NOC National Oceanography Centre (NOC) design team for the Ellsworth project explained the benefits of using polyurethanes:

“The NOC selected polyurethane as the best candidate material for the bellows, as not only did it meet the temperature and performance requirements, it could also be clear. “This was not 100% necessary but if you are doing something that hasn’t been tried before in an extreme environment it’s good to be able to see what’s going on.””

The 5m long polyurethane bellows remain flexible down to -30° Celsius and can withstand exposure to hydrogen peroxide vapour (which scientists use to keep it sterile). Using the bellows provides a sterile environment to house the water collection tubes, and to allow for effective measures of salinity, temperature, pressure, oxygen levels and pH balance of the ice sheet and lake.

 

Click here for more information and videos on the Lake Ellsworth programme.

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