Facing global changes, substantial modifications in soil microbes and their functions have been widely evidenced and connected. However, the response of soil microbial respiration (MR) to increasing nitrogen (N) deposition and the role of microbial characteristics in controlling this response remain elusive. In this study, we quantified the intensity of the soil MR in terrestrial ecosystems that suffered elevated N deposition. High‐throughput quantitative sequencing and phospholipid fatty acids were employed to analyse microbial community properties and biomass, whilst microbial necromass was quantified using biomarker amino sugars. Our results revealed that soil MR kept stable under N deposition. Microorganisms maintained their respiration rates by modifying the characteristics of enzymes rather than altering microbial community properties or biomass. Notably, soil MR increased with latitude across study sites, which was attributed to the restriction of microbial activity by bacterial necromass. Supporting this observation, the recalcitrance of the soil carbon (C) pool to microbial degradation was evidenced to be the stability mechanism underlying the spatial variations in MR. Overall, we propose that MR is resistant to short‐term N deposition, whilst it exhibits a pronounced latitude dependence as shaped by the recalcitrant C pool. Our findings provide crucial insights into the microbial mechanisms of soil C dynamics under global change, contributing to the advancement of soil C models.

中文翻译：

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土壤微生物呼吸对氮沉降没有反应，但随着纬度的增加而增加


面对全球变化，土壤微生物及其功能的重大改变已被广泛证明和联系。然而，土壤微生物呼吸（MR）对氮（N）沉降增加的响应以及微生物特征在控制这种响应中的作用仍然难以捉摸。在这项研究中，我们量化了氮沉降升高的陆地生态系统中土壤MR的强度。采用高通量定量测序和磷脂脂肪酸来分析微生物群落特性和生物量，同时使用生物标志物氨基糖对微生物坏死物进行定量。我们的结果表明，土壤 MR 在氮沉降下保持稳定。微生物通过改变酶的特性而不是改变微生物群落特性或生物量来维持其呼吸速率。值得注意的是，不同研究地点的土壤MR随着纬度的增加而增加，这归因于细菌坏死物对微生物活动的限制。支持这一观察结果的是，土壤碳（C）库对微生物降解的抵抗被证明是 MR 空间变化的稳定机制。总的来说，我们认为磁流能抵抗短期氮沉积，同时它表现出明显的纬度依赖性，如顽固的碳库所形成的。我们的研究结果为全球变化下土壤碳动态的微生物机制提供了重要的见解，有助于土壤碳模型的进步。