A reservoir of briny liquid buried deep beneath an Antarctic glacier supports hardy microbes that have lived in isolation for millions of years, researchers report April 17 in the journal Science.
The discovery of life in a place where cold, darkness, and lack of oxygen would previously have led scientists to believe nothing could survive comes from a team led by researchers at Harvard University and Dartmouth College. Their work was funded by the National Science Foundation, NASA, and Harvard’s Microbial Sciences Initiative.
Despite their profound isolation, the microbes are remarkably similar to species found in modern marine environments, suggesting that the organisms now under the glacier are the remnants of a larger population that once occupied an open fjord or sea.
“It’s a bit like finding a forest that nobody has seen for 1.5 million years,” says Ann Pearson, Thomas D. Cabot Associate Professor of Earth and Planetary Sciences in Harvard’s Faculty of Arts and Sciences. “Intriguingly, the species living there are similar to contemporary organisms, and yet quite different — a result, no doubt, of having lived in such an inhospitable environment for so long.”
“This briny pond is a unique sort of time capsule from a period in Earth’s history,” says lead author Jill Mikucki, now a research associate in the Department of Earth Sciences at Dartmouth and visiting fellow at Dartmouth’s Dickey Center for International Understanding and its Institute of Arctic Studies. “I don’t know of any other environment quite like this on Earth.”
Chemical analysis of effluent from the inaccessible subglacial pool suggests that its inhabitants have eked out a living by breathing iron leached from bedrock with the help of a sulfur catalyst. Lacking any light to support photosynthesis, the microbes have presumably survived by feeding on the organic matter trapped with them when the massive Taylor Glacier sealed off their habitat an estimated 1.5 to 2 million years ago.