According to Penn State researchers Vanya I. Miteva, research associate, and Jean E. Brenchley, professor of microbiology and biotechnology, the majority of the microbes they discovered in an ice-core sample taken from the glacier were less than 1 micron in size--smaller than most commonly known bacteria, which range from 1 to 10 microns. In addition, a large portion of the cells appeared to be even smaller and passed through filters with 0.2-micron pores. The scientists are interested in understanding how microbial life can be preserved in polar ice sheets for hundreds of thousands of years under stresses that include subzero temperatures, desiccation, high pressures, and low oxygen and nutrient concentrations. Because the ice was mixed with the ancient permafrost at the bottom of the glacier, the microbes could have been trapped there for perhaps millions of years.
"We are particularly interested in the formation of ultra-small cells as one possible stress-survival mechanism, whether they are starved minute forms of known normal-sized microbes or intrinsically dwarf novel organisms, and also whether these cells are able to carry on metabolic processes while they are so highly stressed," Miteva says. Physiological changes that accompany the reduction of a cell's size may allow it to become dormant or to maintain extremely low activity with minimal energy.
"Many of these ice-core microbes are related to a variety of ultra-small microorganisms from other cold environ
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Contact: Barbara Kennedy
science@psu.edu
814-863-4682
Penn State
26-May-2004