[1] Fluxes of N 2 O, NO, NO 2 , CO 2 , and CH 4 were measured with high temporal resolution for 3 months at a tropical rain forest site in Queensland, Australia, using automated measuring systems. During this period, representing the transition between dry and wet season, huge pulses of NO emissions from the soil exceeding 500 mg N m À2 h À1were observed with the onset of the first rainfalls. . Though a significant amount of the NO emitted from the soil was redeposited to the soil surface after its oxidation to NO 2 (0.7 kg N ha À1 ), the observed magnitude of net NO x release from the soil indicates that NO x emissions from tropical rain forest ecosystems are seriously underestimated. The mean CO 2 emission was 159.0 mg C m À2 h À1 (range: 36.3-284.8 mg C m À2 h À1 ) and thus >2 magnitudes higher than NO emissions. Among the C-and N-trace gases measured, the temporal variability of CH 4 uptake was the lowest. The mean uptake rate for CH 4 was

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The difficulty of measuring gross N2O production and consumption in soil impedes our ability to predict N2O dynamics across the soil-atmosphere interface. Our study aimed to disentangle these processes by comparing measurements from gas-flow soil core (GFSC) and 15N2O pool dilution (15N2OPD) methods. GFSC directly measures soil N2O and N2 fluxes, with their sum as the gross N2O production, whereas 15N2OPD involves addition of 15N2O into a chamber headspace and measuring its isotopic dilution over time. Measurements were conducted on intact soil cores from grassland, cropland, beech and pine forests. Across sites, gross N2O production and consumption measured by 15N2OPD were only 10% and 6%, respectively, of those measured by GFSC. However, 15N2OPD remains the only method that can be used under field conditions to measure atmospheric N2O uptake in soil. We propose to use different terminologies for the gross N2O fluxes that these two methods quantified. For 15N2OPD, we suggest using ‘gross N2O emission and uptake’, which encompass gas exchange within the 15N2O-labelled, soil air-filled pores. For GFSC, ‘gross N2O production and consumption’ can be used, which includes both N2O emitted into the soil air-filled pores and N2O directly consumed, forming N2, in soil anaerobic microsites.