Fig. 3: Stable isotope signatures of tropical forest soil N2O fluxes.
From: Low N2O and variable CH4 fluxes from tropical forest soils of the Congo Basin
Isotope map of δ18O vs. δ15N adapted from Koba et al. (2009)33 of tropical forest soil N2O fluxes35,79,80,81 and riverine N2O82 derived from literature and this study with overall site medians given in ‰. Note, values from Koehler et al. (2012) and Pérez et al. (2000) are fully or partly from soil pore air measurements. Arrow indicates empirical reduction vector with the ratio of 2.4 (ε18O/ε15N)33. Rectangles depict literature ranges of δ18O vs. δ15N for the N2O production from nitrification and denitrification. Asterisk (*) represents isotope composition of tropospheric air as reference44. Error bars indicate standard deviation.
