Table 1.

Measured and Calculated Limits on Respiration and O₂/H₂O₂ Availability

Limit	[O2] nM*	pO2 (bar)
Observed lower growth limit	3	2 × 10−6
Extrapolated lower growth limit†	0.05	4 × 10−8
Average surface O2 (2-bar CO2 model)	8 × 10−6	6 × 10−12
Transient surface O2 (equinox model)	7 × 10−4	5 × 10−10
Transient surface O2 (winter solstice model)	3 × 10−3	2 × 10−9
Maximum transient surface O2	4	3 × 10−6

Limit	[H2O2] nM	pH2O2 (bar)
Average surface H2O2 (2-bar CO2 model)	0.16	2 × 10−15

Henry's Law constants at 25^°C:

O₂: 1.3 × 10⁻³ mol/L/bar

H₂O₂: 8.2 × 10⁴ mol/L/bar

^*1 nM = 10⁻⁹ mol/L.

^†For 0.5 μm diameter cells (Stolper et al., 2010).