Figure 5.

Rates of alkaline phosphatase activity (APA, fmole MUF cell⁻¹ h⁻¹) in Halothece sp. PCC 7418 under ${\mathrm{NO}}_3^{-}$ starvation conditions compared with the optimal ${\mathrm{NO}}_3^{-}$ treatments under (A) treatment conditions: [Low ${\mathrm{P}\mathrm{O}}_4^{3-}$–Low Fe], [Low ${\mathrm{P}\mathrm{O}}_4^{3-}$–High Fe], and [High ${\mathrm{P}\mathrm{O}}_4^{3-}$–High Fe] and (B) under re-inoculum of nutrients in treatment conditions: [Low ${\mathrm{P}\mathrm{O}}_4^{3-}$–Low Fe, + ${\mathrm{P}\mathrm{O}}_4^{3-}$ + Fe + ${\mathrm{NO}}_3^{-}$] and [Low ${\mathrm{P}\mathrm{O}}_4^{3-}$–Low Fe + ${\mathrm{P}\mathrm{O}}_4^{3-}$ + Fe]. ${\mathrm{P}\mathrm{O}}_4^{3-}$ is represented as Pi. Values are the mean, and the error bar is the spanning range between the duplicate measurements.