Soil organic carbon storage in soil carbon models is highly sensitive to microbial carbon use efficiency (CUE); thus, to reliably predict C storage requires quantifying the response of CUE to warming. By conducting a meta-analysis of 87 observations from field warming experiments worldwide, we found that field warming has no significant effect on CUE, which remains constant at 0.35 ± 0.19 (mean ± SD) on average. The effect of field warming on CUE is independent of climate factors, incubation temperatures, ecosystem types, warming methods, or CUE measurement methods. The field warming effect on CUE was best explained by the response ratios of microbial biomass–specific growth and microbial biomass–specific respiration according to a multi-model selection, and there was a limited effect of warming on microbial biomass–specific growth and microbial biomass–specific respiration. Overall, the effect of field warming on CUE may be attributed to microbial acclimation. Similarly, insignificant effect of laboratory warming on CUE was observed. Our work highlights that current soil carbon models assuming that CUE decreases with warming may underestimate future soil carbon storage, and calls for more research to explore the regulatory role of microbial community attributes on CUE.

中文翻译：

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田间增温对土壤微生物碳利用效率的影响——Meta分析


土壤碳模型中的土壤有机碳储存对微生物碳利用效率（CUE）高度敏感；因此，要可靠地预测碳储存需要量化 CUE 对变暖的响应。通过对全球 87 个野外变暖实验的观测结果进行荟萃分析，我们发现野外变暖对 CUE 没有显着影响，平均保持在 0.35 ± 0.19（平均值 ± 标准差）。田间变暖对 CUE 的影响与气候因素、孵化温度、生态系统类型、变暖方法或 CUE 测量方法无关。根据多模型选择，田间变暖对 CUE 的影响可以通过微生物生物量 - 特定生长和微生物生物量 - 特定呼吸的响应比来最好地解释，并且变暖对微生物生物量 - 特定生长和微生物生物量的影响有限–特定呼吸。总体而言，田间变暖对 CUE 的影响可能归因于微生物的适应。同样，实验室变暖对 CUE 的影响也微不足道。我们的工作强调，目前的土壤碳模型假设 CUE 随着变暖而减少，可能会低估未来的土壤碳储存量，并呼吁进行更多研究来探索微生物群落属性对 CUE 的调节作用。