French biochemist Sébastien Fontaine spent fifteen years sterilizing soil with gamma radiation to measure its carbon release in the absence of microbes. Sealed jars continued emitting carbon dioxide for weeks, then months, defying expectations that respiration would cease. The surprising persistence prompted a series of repeat experiments to rule out contamination.

In a 2025 Science Advances paper, Fontaine’s team reported that the inert soil consumed oxygen and produced CO₂ for six years. Adding yeast enzymes sparked a spike in emissions, suggesting non‑biological catalysts amplified a reaction resembling sugar metabolism. Electron‑flow measurements showed currents several times higher than a salt‑water control, hinting at a Krebs‑cycle‑like electron transfer.

If sterile earth can support such chemistry, the findings blur the line between geology and biology and lend weight to theories that metabolic pathways predate living cells. Researchers note that iron and aluminum oxides in soils could act as natural catalysts, offering a plausible route for pre‑life chemistry on early Earth.