Saturday, October 21, 2006

Newfound Bacteria Fueled by Radiation

A team of scientists has found bacteria living nearly two miles below ground, dining on sulfur in a world of steaming water and radioactive rock. What is unusual is that their underground home contains no nutrients traceable to photosynthesis.

The microbes from the South African mine appear to exist outside this food chain. The underground chemistry appears to go like this:

First, water molecules -- H2O -- are split by radioactive particles. The result is hydrogen, oxygen and hydrogen peroxide. The latter two substances then attack the mineral pyrite (also known as iron sulfide or "fool's gold"), making sulfate through a process called oxidation.

The bacteria then uses the hydrogen to turn the sulfate back to sulfide, a process known as reduction. In doing so, it captures some of the energy in the sulfate's chemical bonds, which it uses to make ATP, the molecule that is the universal coin of energy exchange in living things.

They live 45 to 300 years between cell divisions; in comparison, some strains of E. coli bacteria can divide every 20 minutes under ideal conditions.
Good to know that whatever happens above the surface, these little guys will continue to live on for millions of years fueled by radiation.

via Washington Post

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