兰州大学凌宁教授团队最新的研究结果显示，在高山土壤中，不对称的冬季增温比对称的全年增温更能降低微生物的碳利用效率和生长。相关论文于2024年10月14日发表在《美国科学院院刊》上。

据介绍，不对称的季节性增温趋势在陆地生态系统中非常明显，冬季气温上升幅度大于夏季。然而，人们对这种不对称的季节变暖对土壤微生物碳代谢和生长的影响仍然知之甚少。

利用¹⁸O同位素标记，该团队人员进行了长达十年的，实验性季节变暖对高山草地生态系统微生物碳利用效率（CUE）和生长的影响的研究。此外，研究还采用¹⁸O-H₂O定量稳定同位素探测方法，对这些生态系统中分类群特异性细菌的生长进行了评价。结果表明，全年对称增温使微生物生长速率降低了31%，CUE降低了22%。与全年对称增温相比，不对称冬季增温导致微生物生长率进一步下降27%，微生物CUE进一步下降59%。长期变暖增加了微生物碳限制，特别是在不对称冬季变暖下。

长期增温抑制了大多数细菌属的生长速率，与全年增温相比，非对称冬季增温对特定属（如Gp10、Actinomarinicola、Bosea、Acidibacter和Gemmata）的生长速率，具有更强的抑制作用。

细菌生长在系统发育上是保守的，但在变暖条件下，这种保守性减弱，主要是由于细菌生理状态的变化，而不是细菌种类和群落组成的数量的变化。总体而言，长期变暖加剧了微生物碳限制，降低了微生物生长和CUE，其中不对称冬季变暖的影响更为明显。研究结果强调，了解这些影响对于预测全球变暖进程中的土壤碳循环至关重要。

附：英文原文

Title: Asymmetric winter warming reduces microbial carbon use efficiency and growth more than symmetric year-round warming in alpine soils

Author: Li, Ling, Xu, Qicheng, Jiang, Shengjing, Jing, Xin, Shen, Qirong, He, Jin-Sheng, Yang, Yunfeng, Ling, Ning

Issue&Volume: 2024-10-14

Abstract: Asymmetric seasonal warming trends are evident across terrestrial ecosystems, with winter temperatures rising more than summer ones. Yet, the impact of such asymmetric seasonal warming on soil microbial carbon metabolism and growth remains poorly understood. Using ¹⁸O isotope labeling, we examined the effects of a decade-long experimental seasonal warming on microbial carbon use efficiency (CUE) and growth in alpine grassland ecosystems. Moreover, the quantitative stable isotope probing with ¹⁸O-H₂O was employed to evaluate taxon-specific bacterial growth in these ecosystems. Results show that symmetric year-round warming decreased microbial growth rate by 31% and CUE by 22%. Asymmetric winter warming resulted in a further decrease in microbial growth rate of 27% and microbial CUE of 59% compared to symmetric year-round warming. Long-term warming increased microbial carbon limitations, especially under asymmetric winter warming. Long-term warming suppressed the growth rates of most bacterial genera, with asymmetric winter warming having a stronger inhibition on the growth rates of specific genera (e.g., Gp10, Actinomarinicola, Bosea, Acidibacter, and Gemmata) compared to symmetric year-round warming. Bacterial growth was phylogenetically conserved, but this conservation diminished under warming conditions, primarily due to shifts in bacterial physiological states rather than the number of bacterial species and community composition. Overall, long-term warming escalated microbial carbon limitations, decreased microbial growth and CUE, with asymmetric winter warming having a more pronounced effect. Understanding these impacts is crucial for predicting soil carbon cycling as global warming progresses.

DOI: 10.1073/pnas.2401523121

Source: https://www.pnas.org/doi/abs/10.1073/pnas.2401523121