Appl Environ Microbiol. 1997 Oct;63(10):3872-7. doi: 10.1128/aem.63.10.3872-3877.1997.
Peak emissions of NO and N(inf2)O are often observed after wetting of soil. The reactions to sudden changes in the aeration of cultures of nitrifying and denitrifying bacteria with respect to NO and N(inf2)O emissions were compared to obtain more information about the microbiological aspects of peak emissions. In continuous culture, the nitrifier Nitrosomonas europaea and the denitrifiers Alcaligenes eutrophus and Pseudomonas stutzeri were cultured at different levels of aeration (80 to 0% air saturation) and subjected to changes in aeration. The relative production of NO and N(inf2)O by N. europaea, as a percentage of the ammonium conversion, increased from 0.87 and 0.17%, respectively, at 80% air saturation to 2.32 and 0.78%, respectively, at 1% air saturation. At 0% air saturation, ammonium oxidation and N(inf2)O production ceased but NO production was enhanced. Coculturing of N. europaea with the nitrite oxidizer Nitrobacter winogradskyi strongly reduced the relative levels of NO and N(inf2)O production, probably as an effect of the lowered nitrite concentration. After lowering the aeration, N. europaea produced large short-lasting peaks of NO and N(inf2)O emissions in the presence but not in the absence of nitrite. A. eutrophus and P. stutzeri began to denitrify below 1% air saturation, with the former accumulating nitrite and N(inf2)O and the latter reducing nitrate almost completely to N(inf2). Transition of A. eutrophus and P. stutzeri from 80 to 0% air saturation resulted in transient maxima of denitrification intermediates. Such transient maxima were not observed after transition from 1 to 0%. Reduction of nitrate by A. eutrophus continued 48 h after the onset of the aeration, whereas N(inf2)O emission by P. stutzeri increased for only a short period. It was concluded that only in the presence of nitrite are nitrifiers able to dominate the NO and N(inf2)O emissions of soils shortly after a rainfall event.
NO 和 N(inf2)O 的峰值排放通常发生在土壤润湿之后。为了更深入地了解峰值排放的微生物学方面，我们比较了硝化和反硝化细菌培养物对通气变化的反应，以了解 NO 和 N(inf2)O 排放的相关信息。在连续培养中，硝化菌 Nitrosomonas europaea 和反硝化菌 Alcaligenes eutrophus 和 Pseudomonas stutzeri 在不同的通气水平（80%至 0%空气饱和度）下进行培养，并进行通气变化。N. europaea 的相对 NO 和 N(inf2)O 生成量（占铵转化的百分比）分别从 80%空气饱和度时的 0.87%和 0.17%增加到 1%空气饱和度时的 2.32%和 0.78%。在 0%空气饱和度下，铵氧化和 N(inf2)O 生成停止，但 NO 生成增强。N. europaea 与亚硝酸盐氧化菌 Nitrobacter winogradskyi 共培养强烈降低了相对的 NO 和 N(inf2)O 生成水平，这可能是由于亚硝酸盐浓度降低的影响。降低通气后，N. europaea 在有亚硝酸盐但没有亚硝酸盐的情况下产生大量短暂的 NO 和 N(inf2)O 排放峰值。A. eutrophus 和 P. stutzeri 在空气饱和度低于 1%时开始反硝化，前者积累亚硝酸盐和 N(inf2)O，后者将硝酸盐几乎完全还原为 N(inf2)。A. eutrophus 和 P. stutzeri 从 80%空气饱和度过渡到 0%空气饱和度会导致反硝化中间产物的瞬时最大值。在从 1%过渡到 0%时，没有观察到这种瞬时最大值。A. eutrophus 对硝酸盐的还原持续了通气开始后 48 小时，而 P. stutzeri 对 N(inf2)O 的排放仅在短时间内增加。因此，只有在存在亚硝酸盐的情况下，硝化菌才能在降雨事件后不久主导土壤中 NO 和 N(inf2)O 的排放。
