We assessed the response of soil microbial nitrogen (N) cycling and associated functional genes to elevated temperature at the global scale. A meta‐analysis of 1,270 observations from 134 publications indicated that elevated temperature decreased soil microbial biomass N and increased N mineralization rates, both in the presence and absence of plants. These findings infer that elevated temperature drives microbially mediated N cycling processes from dominance by anabolic to catabolic reaction processes. Elevated temperature increased soil nitrification and denitrification rates, leading to an increase in N₂O emissions of up to 227%, whether plants were present or not. Rates of N mineralization, denitrification and N₂O emission demonstrated significant positive relationships with rates of CO₂ emissions under elevated temperatures, suggesting that microbial N cycling processes were associated with enhanced microbial carbon (C) metabolism due to soil warming. The response in the abundance of relevant genes to elevated temperature was not always consistent with changes in N cycling processes. While elevated temperature increased the abundances of the nirS gene with plants and nosZ genes without plants, there was no effect on the abundances of the ammonia‐oxidizing archaea amoA gene, ammonia‐oxidizing bacteria amoA and nirK genes. This study provides the first global‐scale assessment demonstrating that elevated temperature shifts N cycling from microbial immobilization to enhanced mineralization, nitrification and denitrification in terrestrial ecosystems. These findings infer that elevated temperatures have a profound impact on global N cycling processes with implications of a positive feedback to global climate and emphasize the close linkage between soil microbial C and N cycling.

中文翻译：

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温度升高会使全球陆地生态系统中的土壤氮循环从固定微生物转变为增强矿化，硝化和反硝化作用。

我们评估了全球范围内土壤微生物氮（N）循环和相关功能基因对高温的响应。对来自134个出版物的1,270个观测值进行的荟萃分析表明，无论有无植物，升高的温度都会降低土壤微生物生物量氮并增加氮矿化率。这些发现表明，升高的温度驱动了微生物介导的N循环过程，从合成代谢的主导作用转变为分解代谢的反应过程。升高的温度增加了土壤硝化和反硝化率，导致无论是否存在植物，N ₂ O排放量最多增加227％。N矿化，反硝化和N _2的速率在高温下，O的排放与CO _2的排放速率具有显着的正相关关系，这表明由于土壤变暖，微生物的N循环过程与微生物碳（C）代谢增强有关。大量相关基因对高温的反应并不总是与N个循环过程的变化一致。高温会增加有植物的nirS基因和无植物的nosZ基因的丰度，但对氨氧化古细菌amoA基因，氨氧化细菌amoA和nirK的丰度没有影响。基因。这项研究提供了第一个全球规模的评估，表明在陆地生态系统中，温度升高使氮循环从固定微生物转变为增强矿化，硝化和反硝化。这些发现表明，高温对全球氮循环过程产生了深远的影响，对全球气候产生了积极反馈，并强调了土壤微生物碳氮循环之间的紧密联系。