Overview
- A Caltech-led team headed by postdoctoral geobiologist Tristan Caro revived microbes from roughly 40,000-year-old Alaskan permafrost sampled in a tunnel north of Fairbanks.
- Permafrost material incubated for six months at 4°C and 12°C transitioned from minimal activity to membrane repair, community reorganization, and biofilm formation.
- Tracer use and lipid analyses indicated cold-survival strategies during reactivation, including increased synthesis of glycolipids.
- Initial gas releases were traced to ancient bubbles in the ice before later emissions were confirmed as microbially produced CO2 and methane.
- Researchers warn of a warming feedback because permafrost holds about twice the carbon now in the atmosphere, and they report no current evidence of direct human health risk.