where RNitrbulk (x) is nitrification rate at given oxygen concentration in bulk water (g m3 d1), CO2 ðxÞ is oxygen concentration at a given depth x (g m3), KO2 = 0.4 g m3, Rmax is maximum nitrification rates measured at 5 cm depth (g m3 d1).
The calculated nitrification rates were plotted against their respective depths and curves fitted. Equations of best fit obtained were integrated using Eq. (5).