Next week a British engineering team heads off to Antarctica for the first stage of an ambitious scientific mission to collect water and sediment samples from a lake buried beneath three kilometers of solid ice. This extraordinary research project, at the frontier of exploration, will yield new knowledge about the evolution of life on Earth and other planets, and will provide vital clues about the Earth’s past climate. This is one of the most remote and hostile environments on Earth with —25°C temperatures. Their task is to prepare the way for the deep-field research mission that will take place one year later. In October 2012 a team of 10 scientists and engineers, which includes academics from the University of Bristol, will use state of the art hot-water drilling technology to make a three kilometer bore hole through the ice. They will then lower a titanium probe to measure and sample the water followed by a corer to extract sediment from the lake. Lake Ellsworth is likely to be the first of Antarctica’s 387 known subglacial lakes to be measured and sampled directly through the design and manufacture of space-industry standard clean technology.
Lake Ellsworth is a subglacial lake located in West Antarctica under approximately 3.4 km of ice. It is approximately 10 km long and is estimated to be tens of meters in depth. It is strongly considered as a site for direct exploration due to the possibility that it may harbor unique life forms as well as its relatively easy accessibility. The lake is named for the American explorer Lincoln Ellsworth.
There are many other buried lakes such as Lake Vostok (the largest), Lake Sovetskaya, and Lake Concordia.
This particular lake, which is about six miles long and thirty feet deep, has been chosen because it's one of the easiest subglacial lakes to access - relatively speaking, of course - and scientists believe it's one of the best candidates to harbor unique forms of microbial life that have evolved in the half a million years of isolation and darkness.
Dr David Pearce, Science Coordinator at British Antarctic Survey, is part of the team leading the search for life in the lake water. He says: "Finding life in a lake that could have been isolated from the rest of the biosphere for up to half a million years will tell us so much about the potential origin of and constraints for life on Earth, and may provide clues to the evolution of life on other extraterrestrial environments. If we find nothing this will be even more significant because it will define limits at which life can no longer exist on the planet."
The unique five meter long water sampling probe was designed and built by engineers at the National Oceanography Centre in Southampton. Made of the highest grade of titanium to ensure maximum sterility and strength, it will collect 24 water samples at different lake depths. It will also capture the top layer of sediments at the lake-floor / water interface.
Professor Tranter said: "We already know what the chemical composition of ice melting into the lake is, and so we hope to infer the types of chemical processes that are occurring in the lake by comparison of the lake water with the ice melt. We are confident that some of the chemical differences will be as a consequence of microbial processes, and so we can help prove that microbial life is active biogeochemically beneath Antarctica. We also hope to conduct some simple experiments on the mud on the lake floor, in collaboration with Professor Mike Bentley, to see how chemically reactive it is, and how much solute it can provide to the lake over time. We can then work out how quickly water flows through the lake on the basis of how much salt is contained in the lake water, relative to the melting ice and the solute in the mud pore waters."
Scientists at British Antarctic Survey and Durham University, working in partnership with Austrian business UWITEC, have designed and built a sediment corer, which can extract a core up to three meters long. The unique percussion-driven piston corer is strong enough to penetrate even the most compacted glacial sediments to extract a core sample.
For further information: http://www.bristol.ac.uk/news/2011/7953.html