Figure 1. The predicted hydrogen concentration over time at the observation point 0.5 cm from the gas phase over the course of the experiment shown with (A) linear axes and (B) log-linear axes.

The 2.5–23 μM threshold, at which hydrogenotrophic methanogens have been shown to use H₂ in pure culture studies²⁴,²⁵,²⁶,²⁷, is reached at approximately 10 minutes.