Fe2+ disproportionation within iron-rich alkaline vent analogues reveals proto-bioenergetic systems

Journal article

International audienceAlkaline hydrothermal vents are plausible environments for the emergence of life on Earth. By means of a simplified analogical reconstruction of the vent-ocean interface of these systems reproducing early Earth conditions, we show that iron (oxy-hydr)oxide minerals may have carried out proto-bioenergetic processes driven by pH and redox gradients. The initial pH gradient precipitates the iron (oxy-hydr)oxide mineral barriers (magnetite, green rust and amakinite) and yields reducing conditions, enabling the production of metallic iron at room temperature via the disproportionation of Fe2+ to Fe3+ and Fe0. The crystallographic association of Fe0 surrounded by magnetite suggests the coupling of Fe3+ / H2 co-production at ambient temperature by amakinite oxidation with the thermodynamically unfavorable reduction of Fe2+ to Fe0. This abiotic disproportionation process coupling exergonic and endergonic reactions may serve as a proto-bioenergetic mechanism increasing the non-equilibrium reduction state of the system and offers an interesting analog of the biological electronic bifurcation reaction, the free energy coupling being a fundamental thermodynamic trait of life-as-we-know-it

Authors: Truong, C; Gaudu, N; Farr, O; Clouet, A; Ferry, D

• Publication status: Published
• Peer review status: Peer reviewed
• Publisher: Nature Research
• Journal: Nature Communications
• Volume: 16
• Issue: 1
• Pages: 10682-10682
• Publication date: 2025-11-27
• DOI: 10.1038/s41467-025-65716-w
• EISSN: 2041-1723
• ISSN: 2041-1723
• Language: English
• Keywords: Hydrothermal circulation; Abiogenesis; Exergonic reaction; Metal; Coupling (piping); Redox; Disproportionation; Magnetite