Table 2.

Results of incubations in the Namibian Upwelling zone.

[O2] μM	N tracers	Incubation time (hours)	Ammonia oxidation rate (nM/day)	δ15N-N2O (‰)	stdev δ15N-N2O (‰)	δ18O-N2O (‰)	stdev δ18O-N2O (‰)	Total N2O (nmoles)	Error total N2O (nmoles)	n
Kill controls	15${\text{NH}}_4^{+}$, NA NO2−	0		7.0	0.9	42.8	0.7			3
220 ± 12	15${\text{NH}}_4^{+}$, NA NO2−	24.0	3.0 ± 0.3	10.8	1.5	43.3	0.5	2.7	0.08	2
50 ± 10	15${\text{NH}}_4^{+}$, NA NO2−	26.0	2.4 ± 0.3	13.8	0.9	44.0	0.2	2.0	0.05	3
20 ± 10	15${\text{NH}}_4^{+}$, NA NO2−	24.1	2.3 ± 0.2	20.8	2.0	46.0	0.5	1.7	0.05	3
Kill controls	NA ${\text{NH}}_4^{+}$, 15NO2−	0		6.8	0.2	45.5	0.5			3
220 ± 12	NA ${\text{NH}}_4^{+}$, 15NO2−	23.9	–	7.3	0.1	45.6	0.1	2.5	0.08	2
50 ± 10	NA ${\text{NH}}_4^{+}$, 15NO2−	25.2	–	8.0	0.5	45.2	0.2	1.9	0.06	3
20 ± 10	NA ${\text{NH}}_4^{+}$, 15NO2−	24.0	–	11.3	1.8	44.5	0.5	1.5	0.04	3