Table 2.

pH tolerance, pH optimum (pH_opt), body size (from Lugol-fixed cells), and maximum growth rate (μ_max) of Oxytricha acidotolerans sp. nov. and Urosomoida sp.

Parameter	Oxytricha acidotolerans	Urosomoida sp.
pH tolerance	2.5 to >7.1	2.5 to ∼5.6
pHopt a	5.2	3.5
Cell length at pHopt (μm)	71.0 ± 9.0	48.9 ± 7.2
Cell width at pHopt (μm)	34.5 ± 5.9	22.4 ± 3.2
Cell length:width ratio at pHopt	2.1	2.2
μmax (d−1)	0.51b (0.53)c	0.37b (0.51)c

^apH at μ_max.

^bAverage of three replicates.

^cHighest individual growth rate.