Table 1.

O₂ concentration in PFD used in the experiments

	Composition of PFD mixture (per ml)	Concentration of O2 (μM O2 ml−1 PFD)
		From air	From pure O2	Total
PFD(air)	1 ml PFD(air)	4	0	4
${\text{PFD}}_{(+20\%{\text{O}}_2)}$	0.8 ml PFD(air) + 0.2 ml ${\text{PFD}}_{({\text{O}}_2)}$	3	4	7
${\text{PFD}}_{(+40\%{\text{O}}_2)}$	0.6 ml PFD(air) + 0.4 ml ${\text{PFD}}_{({\text{O}}_2)}$	2	8	10
${\text{PFD}}_{(+60\%{\text{O}}_2)}$	0.4 ml PFD(air) + 0.6 ml ${\text{PFD}}_{({\text{O}}_2)}$	2	12	14
${\text{PFD}}_{(+80\%{\text{O}}_2)}$	0.2 ml PFD(air) + 0.8 ml ${\text{PFD}}_{({\text{O}}_2)}$	1	15	16
${\text{PFD}}_{({\text{O}}_2)}$	1 ml ${\text{PFD}}_{({\text{O}}_2)}$	0	19	19

PFD _(air) PFD saturated by atmospheric air, ${\mathit{PFD}}_{(O_2)}$ PFD saturated by pure O₂

PFD_(air) and ${\text{PFD}}_{({\text{O}}_2)}$ were mixed to obtain O₂-enriched PFD