Figure 4. ${\mathrm{NO}}_3^{-}$, ${\mathrm{NO}}_2^{-}$ and N₂O dynamics by Methylophaga nitratireducenticrescens JAM1 in NH₄Cl-free cultures.

Strain JAM1 was cultured under anoxic (A) or oxic (B) conditions with ${\mathrm{NO}}_3^{-}$ (22 mg-N vial⁻¹) in NH₄Cl-free 1403 medium. ${\mathrm{NO}}_3^{-}$, ${\mathrm{NO}}_2^{-}$ and N₂O concentrations were measured over different time intervals. N₂ concentration was measured in anoxic cultures that were flushed with argon. The results are derived from triplicate cultures. In (A) asterisks denote the sampling times used for RNA extraction (see Fig. 6). Data represent mean values ± SD (n = 3).