生态系统
土壤学
生物量(生态学)
微生物种群生物学
环境科学
陆地生态系统
氮气
氮气循环
全球变化
生态学
环境化学
微生物生态学
土壤微生物学
沉积(地质)
土壤生物学
生态系统服务
营养物
微生物
营养循环
生物
气候变化
土壤生态学
生物地球化学循环
硝化作用
交替稳态
草原
生物地球化学
作者
Kejie Li,Jinyang Wang,Zhenghu Zhou,Jie Wu,Xiaomeng Bo,Mengxue Shen,Jianwen Zou
摘要
Soil microbial communities are key regulators of terrestrial ecosystem functions, yet their long-term responses to atmospheric nitrogen (N) enrichment remain poorly understood. Here, we synthesized a global dataset of 6255 paired observations from 308 field-based N addition experiments to evaluate how ecosystem functionality and microbial attributes respond to N enrichment across varying addition rates and durations. Multivariate linear mixed-effects models revealed that N enrichment enhanced ecosystem functionality by 17.6%, while reducing microbial biomass by 4.2%, with both effects intensifying under higher N addition rates and longer experimental durations. Meta-forest modelling generated high-resolution global maps that further demonstrated stronger ecosystem and microbial responses under long-term N enrichment. At the grid scale, spatial variation in these responses was primarily governed by edaphic factors, particularly soil pH, sand content, and bulk density, rather than by N deposition rates. Notably, we identified a temporal reversal in the relationship between microbial biomass and ecosystem functionality, which was positive in the short term but became increasingly negative in the long term. This transition likely reflects a shift in microbial life-history strategies, where oligotrophic taxa (K-strategists) are progressively replaced by copiotrophic taxa (r-strategists), with consequences for resource-use efficiency and microbial biomass. Together, our findings highlight microbial biomass as a pivotal determinant of long-term ecosystem functionality and underscore the importance of microbial life-history strategy shifts and soil constraints in shaping ecological responses to sustained N enrichment.
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