Hu Junxi, Cui Yongxing, Manzoni Stefano, Zhou Shixing, Cornelissen J Hans C, Huang Congde, Schimel Joshua, Kuzyakov Yakov
College of Forestry, Sichuan Agricultural University, Chengdu, China.
Amsterdam Institute for Life and Environment (A-LIFE), Systems Ecology Section, Vrije Universiteit, Amsterdam, The Netherlands.
Glob Chang Biol. 2025 Jan;31(1):e70036. doi: 10.1111/gcb.70036.
Carbon use efficiency (CUE) of microbial communities in soil quantifies the proportion of organic carbon (C) taken up by microorganisms that is allocated to growing microbial biomass as well as used for reparation of cell components. This C amount in microbial biomass is subsequently involved in microbial turnover, partly leading to microbial necromass formation, which can be further stabilized in soil. To unravel the underlying regulatory factors and spatial patterns of CUE on a large scale and across biomes (forests, grasslands, croplands), we evaluated 670 individual CUE data obtained by three commonly used approaches: (i) tracing of a substrate C by C (or C) incorporation into microbial biomass and respired CO (hereafter C-substrate), (ii) incorporation of O from water into DNA (O-water), and (iii) stoichiometric modelling based on the activities of enzymes responsible for C and nitrogen (N) cycles. The global mean of microbial CUE in soil depends on the approach: 0.59 for the C-substrate approach, and 0.34 for the stoichiometric modelling and for the O-water approaches. Across biomes, microbial CUE was highest in grassland soils, followed by cropland and forest soils. A power-law relationship was identified between microbial CUE and growth rates, indicating that faster C utilization for growth corresponds to reduced C losses for maintenance and associated with mortality. Microbial growth rate increased with the content of soil organic C, total N, total phosphorus, and fungi/bacteria ratio. Our results contribute to understanding the linkage between microbial growth rates and CUE, thereby offering insights into the impacts of climate change and ecosystem disturbances on microbial physiology with consequences for C cycling.
土壤中微生物群落的碳利用效率（CUE）量化了微生物吸收的有机碳（C）中分配到生长的微生物生物量以及用于修复细胞成分的比例。微生物生物量中的这部分碳随后参与微生物周转，部分导致微生物坏死物质的形成，而这些坏死物质可以在土壤中进一步稳定下来。为了大规模且跨生物群落（森林、草原、农田）揭示CUE的潜在调控因素和空间格局，我们评估了通过三种常用方法获得的670个个体CUE数据：（i）通过将底物碳（或碳）掺入微生物生物量和呼吸的二氧化碳（以下简称碳底物）来追踪底物碳，（ii）将水中的氧掺入DNA（氧水），以及（iii）基于负责碳和氮（N）循环的酶的活性进行化学计量建模。土壤中微生物CUE的全球平均值取决于方法：碳底物法为0.59，化学计量建模法和氧水法为0.34。在不同生物群落中，微生物CUE在草地土壤中最高，其次是农田和森林土壤。我们发现微生物CUE与生长速率之间存在幂律关系，这表明更快的碳用于生长对应于维持过程中碳损失的减少以及与死亡率相关。微生物生长速率随土壤有机碳、总氮、总磷含量以及真菌/细菌比率的增加而增加。我们的研究结果有助于理解微生物生长速率与CUE之间的联系，从而深入了解气候变化和生态系统干扰对微生物生理学的影响及其对碳循环的后果。
