Bacteria discovered 2.8km underground
23 October 2006
by Carina Lee
An isolated community of bacteria living 2.8km underground derives all of their energy from the decay of radioactive rocks rather than from sunlight according to studies conducted by a group of scientists. The Princeton University-led group of collaborators dug a 2.8km-deep hole underground near a South African gold mine to unveil these million-year-old bacterial organisms. They found that these unusual microbes were quite comfortable living in nutrient-rich groundwater and sulfidic conditions. Analysis of the water chemistry and how they obtain energy demonstrates these organisms are in a complete class of their own. When samples were analysed, it was clear that their only source of water was from groundwater, and the hydrogen acquired for respiration came from the radioactive decay of rocks containing elements like thorium, uranium, and potassium. Professor in geosciences from Princeton University, Tullis Onstott, explains “These bacteria have been cut off from the surface of the Earth for many millions of years, but have thrived in conditions most organisms would consider to be inhospitable to life. Could these bacterial communities sustain themselves no matter what happened on the surface? If so, it raises the possibility that organisms could survive even on planets whose surfaces have long since become lifeless.” These findings have a big impact for palaeobiologists trying to reconstruct what the environment was like on Earth before it was oxygenated by cyanobacteria. The existence of these bacteria has potential for speculation of life on planets other than our own, namely Mars. |
An electron micrograph of the bacteria that live underground. image:.princeton.edu |
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Original press release from Princeton
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