Buffer gases and redox balance for an oxygenated Martian atmosphere

Determine the required partial pressures and plausible sources of chemically inert buffer gases needed to prevent uncontrolled combustion in a future oxygenated Martian atmosphere, and ascertain whether Mars hosts sufficient accessible electron acceptors (e.g., Fe3+, SO42−, CO32−) to take up H2 associated with photosynthetic O2 production.

Background

If warming enables photosynthesis, O2 could accumulate over centuries. Safe, stable oxygenation likely requires inert buffer gases to control flammability and adequate redox partners to balance biogenic hydrogen.

The authors identify both the buffer gas budget and available electron acceptors as unresolved constraints on long-term atmospheric evolution and biosphere function.

References

However, currently unanswered questions include the needed amount of chemically inert “buffer” gas (and from where this could be sourced) in order to prevent uncontrolled combustion, and whether Mars has sufficient accessible electron acceptors (such as Fe3+, SO42-, and CO32-) to take up the H2 corresponding to O2 build-up from photosynthetic water-splitting.

— A research roadmap for assessing the feasibility of warming Mars  (2604.02242 - Kite et al., 2 Apr 2026) in Section 4.3 (Surface warming and atmospheric thickening together)