Tuesday, October 9, 2007

Microbes can survive for 100,000 years

Microbes can survive trapped inside ice crystals, under 3 kilometres of snow, for more than 100,000 years, a new study suggests.

The study bolsters the case that life may exist on distant, icy worlds in our own solar system. Living bacteria have been found in ice cores sampled at depths of 4 kilometres in Antarctica, though some scientists have argued that those microbes were contaminants from the drilling and testing of the samples in labs.

And in 2005, researchers revived a bacterium that sat dormant in a frozen pond in Alaska for 32,000 years.

Now, physicist Buford Price and graduate student Robert Rohde, both at University of California in Berkeley, US, have found a mechanism to explain how microbes could survive such extreme conditions. They say a tiny film of liquid water forms spontaneously around the microbe. Oxygen, hydrogen, methane and many other gases will then diffuse to this film from air bubbles nearby, providing the microbe with sufficient food to survive.

Thus, virtually any microbe can remain alive in solid ice, resisting temperatures down to -55° Celsius and pressures of 300 atmospheres.

Under such harsh conditions, the microbes would not be able to grow and reproduce, but they would still be able to repair any molecular damage, keeping themselves viable for more than a thousand centuries, the team says. "It is not life as we generally think about it," says Rohde. "[They] are just sitting there surviving, hoping that the ice will melt." To test their hypothesis, the researchers studied ice samples taken at various depths in the Antarctic and Greenland ice sheets. They detected isolated microbes that they say must be trapped inside ice crystals.

Additionally

Just as microbes have been found to survive in a dormant state for thousands of years, mold also has been found in like states. Mold found in the Egyptian pyramids has been successfully cultured thousands of years after the tombs were sealed.

How does this apply to the average home owner? Well, sometimes when the weather is humid, people often complain of a musty smell in their homes. Once the humidity levels drop, the smell tends to go away or lessen. This is because mold needs water to flourish, so when it is humid, the mold thrives, when it is not humid, the mold can go into somewhat of a dormant state and the smell goes away.

So, unless you kill the mold, it will always be there just waiting for moisture (water) to spring back to life.


Thank you NewScientist.com for the article /Daniele Fanelli and Maggie McKee

Boston Biosafety cares about your health

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