Lake Ellsworth offers fresh discoveries

To date, scientists have discovered more than 145 sub-glacial lakes below the ice sheet of Antarctica. These lakes present a unique environment, since they have been isolated from the surface for such a long time. Life here has had to adapt to complete darkness, low levels of nutrients, isolation from the atmosphere and high water pressure. This has resulted in a totally unique biological habitat.

Studying, sampling and drilling these lakes without contaminating them or spreading contamination to other lakes represents a considerable technological and physical challenge. In this regard, investigating the lakes does not differ that much from the exploration of planets in the solar system.

One of the sub-glacial lakes, located in West Antarctica, is Lake Ellsworth, named after US explorer Lincoln Ellsworth. It lies under approximately 3.4 km of ice, is some 10 km in length and scientists estimate the depth to be about 150 metres. Ellsworth is a prime candidate for exploration, because it is possible that it harbours unique life forms and also because it is fairly easy to access.

The Natural Environment Research Council funded provisional geophysical exploration of the lake between 2007 and 2009. Small teams of scientists, who were positioned on the ice above Lake Ellsworth, used radar and seismic surveys to measure the depth of the water and map the lake’s outline. They were able to establish that the lake’s floor contain sediments, which might contain a record of ice sheet history.

This geophysical exploration convinced scientists that Lake Ellsworth was the perfect candidate for further investigation. On the basis of the initial findings the Natural Environment Research Council in the UK approved funding for a direct exploration project that will begin later in 2012.

Scientists will use a hot-water drill to ‘melt’ through the ice layer into the water below. They will then insert a sediment corer, which will recover sediment from the floor of the lake and a probe to test if there is any life in the water. The sediment will provide a valuable insight into the glacial history of the West Antarctic Ice Sheet and the evolution of life forms in the lake.

An advance party has already paved the way for the full team, which is due to arrive later in 2012. They have had to transport drilling equipment over a distance of over 250km across terrain covered with deep snow. On the way, the team had to cross the Ellsworth Mountain range. They had to use powerful tractors towing the bulky containers of equipment on skis and sledges and progress was slow, in fact it took them three days to reach the drilling site.

Professor Martin Siegert, the Programme Principal Investigator of the Lake Ellsworth Project said, “We are now one step closer to finding out if new and unique forms of microbial life could have evolved in this environment… extracted sediment samples could give us an important insight in to the ancient history of the West Antarctic Ice Sheet, including past collapses, which would have implications for future sea level rise.”