The discovery of millions of micro-microbes surviving in a 120,000-year-old ice sample taken from 3,000 meters below the surface of the Greenland glacier will be announced by Penn State University scientists on 26 May 2004 at the General Meeting of the American Society for Microbiology in New Orleans, Louisiana. The discovery is significant because it may help to define the limits for life on Earth as well as elsewhere in the universe, such as on cold planets like Mars.
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 environPage: 1 2 3 Related biology news :1
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