To understand how and to what extent single or multiple perturbations can alter the relationships between the abundances of different nitrifier groups and nitrification, soil microcosms were exposed to six disturbance treatments: a heat shock, cold shock, or control conditions applied to undisturbed soils or to soils that had previously been subjected to a first heat shock. We monitored the recovery of the abundances of four main nitrifier groups (ammonia-oxidizing archaea and bacteria, AOA and AOB, respectively, and Nitrobacter and Nitrospira nitrite oxidizers) as well as nitrification activity for 25 days. AOA were sensitive to cold shocks, whereas AOB were not; the latter were sensitive to heat shock. Despite the variations, both groups were resilient to the first disturbance. In contrast, Nitrobacter was affected by both disturbances, whereas Nitrospira was resistant to both shocks. Prior exposure to a heat shock affected each group’s responses as well as the relationships between them. For example, AOB were more vulnerable to heat shock in pre-exposed soils, whereas under the same circumstances, AOA were resilient. Nitrification activity was resistant to the first disturbances, but a legacy effect was observed, and nitrification was highest in Heat-Heat and lowest in Heat-Cold treatments. Overall, our study shows that within soil nitrifiers, temporal patterns and legacy effects interact to result in complex disturbance responses.

中文翻译：

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极端干扰的历史影响土壤中硝化菌丰度之间的关系

为了了解单个或多个扰动如何以及在多大程度上改变不同硝化基团的丰度与硝化作用之间的关系，土壤微观世界接受了六种扰动处理：热冲击、冷冲击或应用于未受干扰土壤的控制条件或先前经受过第一次热冲击的土壤。我们监测了四个主要硝化菌群（氨氧化古菌和细菌，分别为 AOA 和 AOB，以及硝化细菌和亚硝酸盐氧化剂）的丰度恢复以及硝化活性 25 天。AOA 对冷冲击敏感，而 AOB 则不然；后者对热休克敏感。尽管存在差异，但两组都能够抵御第一次干扰。相比之下，硝化杆菌受到两种干扰的影响，而 Nitrospira 对这两种冲击都有抵抗力。先前暴露于热休克会影响每个组的反应以及它们之间的关系。例如，AOB 在预先暴露的土壤中更容易受到热冲击，而在相同情况下，AOA 具有弹性。硝化活性对第一次干扰具有抵抗力，但观察到遗留效应，硝化作用在热-热处理中最高，在热-冷处理中最低。总的来说，我们的研究表明，在土壤硝化菌中，时间模式和遗留效应相互作用，导致复杂的干扰响应。而在相同情况下，AOA 具有弹性。硝化活性对第一次干扰具有抵抗力，但观察到遗留效应，硝化作用在热-热处理中最高，在热-冷处理中最低。总的来说，我们的研究表明，在土壤硝化菌中，时间模式和遗留效应相互作用，导致复杂的干扰响应。而在相同的情况下，AOA 是有弹性的。硝化活性对第一次干扰具有抵抗力，但观察到遗留效应，硝化作用在热-热处理中最高，在热-冷处理中最低。总的来说，我们的研究表明，在土壤硝化菌中，时间模式和遗留效应相互作用，导致复杂的干扰响应。