TABLE 1.

Comparison of nitrate uptake rates in various species of algae and cyanobacteria and in different culture systems

Species	Free-living or immobilized	Continuous or batch mode	Continuous light or light-dark	NO3− uptake rate (μM h−1)	Reference
Phormidium laminosum	Free-living	Batch	Light-dark	0.25∼0.5a	14
Chlorella vulgaris	Immobilized	Batch	Continuous	7.4	25
Phormidium laminosum	Immobilized	Continuous	Continuous	14.0	42
Synechococcus sp. strain PCC 7942	Free-living	Batch	Continuous	51.8	Present study

^aThis is an estimated figure based on two assumptions: (i) chlorophyll a constitutes 1.5% of the dry weight of cells and (ii) the cell density for the maximal nitrate uptake rate is 500 to 1,000 mg liter⁻¹ at a light intensity of 100 μmol of photons m⁻² s⁻¹. The actual nitrate uptake rate reported by Garbisu et al. (14) was 33.4 nmol (μg of chlorophyll)⁻¹ h⁻¹.