Microbes Found Living in Glacier

A Harvard lab recently discovered single-celled microbes living in isolation for millions of years beneath an Antarctic glacier once believed inhospitable to all life.

The findings below the Taylor Glacier contradicts the long-held belief that subglacial environments, which lack light, oxygen, or food, cannot support life.

The team of researchers, including Ann Pearson of Harvard and Jill Mikucki of Dartmouth, was sponsored by the National Science Foundation, NASA, and Harvard’s Microbial Sciences Initiative.

According to Pearson, an associate professor of earth and planetary sciences, the team based the research on samples collected from Antarctica’s McMurdo Dry Valleys. This region is considered to be one of the world’s most extreme deserts and contains an iron-rich subglacial outflow, Blood Falls, which trickles from the Taylor Glacier.

Pearson said Mikucki would camp out by the falls for weeks at a time for a number of years, waiting for the sporadic melting events during the summer when it would be just warm enough for the glacier to melt and for brine to flow out.

Within this brine, the research team discovered roughly a dozen species of prokaryotic microbes about the size of bacteria buried deep beneath the glacier.

“What’s truly amazing about this discovery is microbial continuity, how microbial communities can survive intense stresses and very dramatic cold stages. These microbes have been living in isolation for millions of years and yet they still bear great resemblance to modern marine species,” Pearson said.

At Harvard’s Hoffman Laboratory, Pearson and her colleagues discovered that these anaerobic microorganisms survive on iron that leaks out from the bedrock with the help of a sulfur catalyst. The microbes have adapted to the hostile subglacial environment by developing a new life cycle in which they breathe iron through sulfur.

Without any light for photosynthesis, the microbes have presumably survived by feeding on the organic matter trapped within their habitat when the massive Taylor Glacier sealed them off an estimated 1.5 million to 2 million years ago.

According to Pearson, there could be a rich and diverse ecosystem that thrives beneath the glaciers. She even suggested that there could perhaps be life on other icy planets in the solar system; below the Martian ice caps or in the ice-covered oceans of Europa, a moon of Jupiter.

Further research on these microbes is being conducted by Jill Mikucki, a research associate in the Department of Earth Sciences at Dartmouth.

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