Fig. 3: N2O yield during ammonia (NH3) oxidation and nitrate (NO3-) reduction, and Pearson’s correlation between the measured rates and the environmental parameters.
From: Particle-associated denitrification is the primary source of N2O in oxic coastal waters
(a–c) N2O yield in the Pearl River Estuary (PRE), Jiulong Estuary (JLE) and Changjiang Estuary (CJE), respectively. The black and white dots denote N2O yield during NO3- reduction and NH3 oxidation, respectively. Data are presented as mean rates ± standard deviation. Errors bars in panels (a–c) are standard deviation on the rates derived from triplicate incubations (n = 3 biologically independent samples). The numbers in the box plots show the median value, and the minima and maxima values, respectively; whiskers and boxes show the 10% and 90% percentile and 25–75% quartile of the measurements, respectively (n = 20, 9, 19 stations in the PRE, JLE, and CJE, respectively). (d) The Pearson’s correlation analysis for samples from all investigated areas (n = 48 biologically independent samples). Color gradient denotes the Pearson correlation coefficients. Only the significant correlations (p < 0.05, two sided) are colored, and the white squares indicate p > 0.05. AO, NO, NR, N2O-NH4+, N2O-NO2-, N2O-NO3- denote the rates of ammonia oxidation, nitrite oxidation, nitrate reduction to nitrite, N2O production from NH4+, N2O from NO2- and N2O from NO3-, respectively. N2O total, N2O yield-oxi, and N2O yield-red mean the total N2O production rate from NH4+, NO2- and NO3-, N2O yield from ammonia oxidation, and N2O yield during NO3- reduction, respectively.
