Table I.

Photosynthetic oxygen evolution in relation to extracellular CA activity in P. micans grown at 2.0 mm DIC, pH 8.3, and resuspended under the conditions indicated at a PFD of 500 μmol m⁻² s⁻¹ at 15°C

Condition	Photosynthetic Oxygen Evolution	External CA
	nmol 106 cells−1 h−1	EU (106 cells−1)
pH 8.3
2.0 mm total DIC	20.47  ± 0.92	0.25  ± 0.01
2.0 mm total DIC plus DBS	2.31  ± 0.20	0.03  ± 0.00
pH 9.0
2.0 mm total DIC	19.78  ± 0.53	0.41  ± 0.03
2.0 mm total DIC plus DBS	2.11  ± 0.13	0.05  ± 0.00

Values are ±se; n = 4.