Sufficiency of Martian electron acceptors for atmospheric O2 buildup

Determine whether Mars contains a sufficient inventory of electron acceptors—specifically carbon, ferric iron, and sulfate—to sequester hydrogen derived from water so that oxygen can accumulate to form the oxygen-rich atmosphere envisioned for a terraformed Mars.

Background

In the proposed terraforming pathway, a long-term oxygen-rich atmosphere would be produced by photosynthesis and sustained only if the corresponding hydrogen from water is effectively sequestered. On Earth, analogous sinks include burial of reduced carbon and reactions with oxidized minerals.

The document flags this as a Potential Showstopper because if Mars lacks adequate electron acceptors, produced oxygen would not accumulate as intended, fundamentally challenging the feasibility of achieving the envisioned oxygen atmosphere.