Found in an intermittent stream draining from the glacier, the evidence includes traces of dissolved organic material and high levels of nitrates, said Mark Williams, a fellow at CU-Boulder's Institute of Arctic and Alpine Research. The high nitrate levels are believed to be a result of microbes metabolizing nitrogen within the glacier, said CU-Boulder graduate student Meredith Knauf.
Rock glaciers are large masses of rock debris interspersed with ice in the high mountains of temperate areas. Moving at speeds of just inches or a few feet a year, they require an extremely cold environment, large amounts of rock debris and enough of a slope to allow them to slide.
"This is a very surprising finding, something we did not expect," said Williams. "The upshot is that we have shown that rock glaciers are not biological deserts as had been previously thought by scientists. This is one more example that microbes can live in the most extreme of environments."
Williams said the microbial "signature" discovered by the team in the rock glacier in the Green Lakes Valley watershed roughly 30 miles west of Boulder, Colo., is similar to that found recently in semi-frozen lakes in the Dry Valleys of Antarctica. The unexpected discovery of microbes in that hostile Antarctica region has enthused scientists hunting for life in inhospitable environments, he said.
Both the amount of dissolved organic matter and nitrate levels from microbial activity in the rock glacier rose dramatically from the late spring to the early fall in 2003, said Knauf of CU-Boulder's geography department. "This increase indicates that the biological signal is coming from meltwater inside the rock glacier, rather than from terrestrial micr