Microbes in 500,000-year-old permafrost breathe, although at a very slow pace, and show other signs of life, according to a new report. If confirmed, the findings would be the first evidence of metabolism remaining active over geologic time scales.
Previously, researchers had extracted bacteria from 250 million-year-old minerals and coaxed them to grow in the lab. Such bacteria probably survived in a dormant, sporelike state (SN: 6/12/99, p. 373).
The new report hints that some types of bacteria instead remain metabolically active over hundreds of thousands of years. "Our evidence suggests there are some living bacteria [in the permafrost]," say