Researchers taking advantage of retreating ice shelves in Antarctica have discovered evidence of life that's been sealed away for nearly 100,000 years. Lake Hodgson on the Antarctic Peninsula, once covered by over 400 meters of ice, is now obscured only by a thin layer three to four meters thick. Scientists carefully drilled through the ice and took samples (abstract) from the layers of mud at the bottom (as much as 93 meters below the lake's surface). "The top few centimetres of the core contained current and recent organisms which inhabit the lake but once the core reached 3.2 m deep the microbes found most likely date back nearly 100,000 years. ... Some of the life discovered was in the form of Fossil DNA showing that many different types of bacteria live there, including a range of extremophiles which are species adapted to the most extreme environments. These use a variety of chemical methods to sustain life both with and without oxygen. One DNA sequence was related to the most ancient organisms known on Earth and parts of the DNA in twenty three percent has not been previously described."