WorldWide Drilling Resource

27 WorldWide Drilling Resource ® NOVEMBER 2013 Extreme Discoveries in Lake Hodgson Adapted from a Press Release by the British Antarctic Survey In the December 2011 issue, WWDR began covering the efforts of scientists and engineers attempting to drill into a subglacial lake in Antarctica ( Drilling into the Unknown) . Though the team was excited about the potential of dis- covering previously unknown life-forms, as well as clues about the future of cli- mate change, those first efforts at Lake Ellsworth had a disappointing ending when technical difficulties forced the project to be put on hold, as WWDR reported in March of this year. Scientists from the British Antarctic Survey (BAS), and the Universities of Northumbria and Edinburgh recog- nized the major technological chal- lenges that go along with the direct sampling of lakes in the interior of Antarctica. With these challenges in mind, they have been searching around retreating margins of the ice sheet for subglacial lakes which are now becom- ing exposed for the first time since they were buried more than 100,000 years ago. This is taking place because parts of the ice sheet are melting due to unprecedented rates of temperature rises at the poles. BAS scientists targeted Lake Hodgson on the Antarctic Peninsula which was covered by more than 1300 feet of ice at the end of the last Ice Age, but is now considered to be an emerg- ing subglacial lake, with a thin covering of only 9-13 feet of ice. Drilling through the ice, they used clean coring techniques to delve into the sediments at the bottom of the lake which is 305 feet deep. Though the lake was thought to be a harsh environment for any form of life, layers of mud at the bottom of the lake were a collective time capsule storing the DNA of microbes which have lived there throughout the mil- lenia. The top few inches of the core contained current and recent organ- isms which inhabit the lake. However, once the core reached almost 11 feet deep, the microbes found most likely date back nearly 100,000 years. Some of the discovered life-forms were in fossil DNA showing many dif- ferent types of bacteria living there, including a range of extremophiles, which are species that use a variety of chemical methods to sustain life both with and without oxygen, thereby adapt- ing to the most extreme environments. Lead author David Pearce, who was at BAS and is now at the University of Northumbria said: “This is the first time microbes Drilling operations at Lake Hodgson have been identified living in the sedi- ments of a subglacial Antarctic lake and indicates that life can exist and potentially thrive in environments we would consider too extreme.” One DNA sequence was related to the most ancient organisms known on earth and parts of the DNA in 23% have not been previously described. Many of the species are likely to be new to science, making clean exploration of the remote lakes isolated under deeper parts of the ice sheet even more pressing. Scientists believe organisms living in subglacial lakes could hold clues for how life might survive on other planets.