Divergent Microbial Metabolic Limitations Across Soil Depths After Two Decades of High Nitrogen Inputs in a Primary Tropical Forest

作者：Chaolong Pang, Z. X. Zhang, Xiaomin Zhu, Wentao Wei, Adnan Mustafa, Weibin Chen, Qionggong Mao, Jianming Mo, Shuai Li, X. L. Lu · 发表于：Global Change Biology · 年份：2025 · DOI：10.1111/gcb.70440 · 被引用次数：22 · 研究领域：Soil Carbon and Nitrogen Dynamics、Soil and Water Nutrient Dynamics、Peatlands and Wetlands Ecology

Soil microorganisms play an important role in soil biogeochemical cycles and ecosystem stability. Elevated atmospheric nitrogen (N) deposition has greatly accelerated terrestrial N cycling processes and altered elemental stoichiometry of substrates, leading to changes in soil microbial metabolic limitation. However, it remains unclear how soil microbial metabolic limitation responds to long-term N additions in highly weathered tropical forests. Here, based on a two-decade N addition experiment in an N-rich primary tropical forest, we explored how chronic N additions affected soil microbial metabolic limitation across soil profiles. In contrast to the traditional view, our results demonstrated that long-term N addition had a depth-selective impact on phosphorus (P) limitation, which was enhanced at the surface soils but not at deeper soils. Soil microorganisms can acclimate to P limitation through downregulating microbial community abundance, where the relative abundance of actinomycetes could indicate P limitation status. We further found that chronic N addition alleviated microbial carbon (C) limitation through increasing soil dissolved organic C (DOC) contents at surface soil layers but intensified microbial C limitation at deeper soils. DOC contents could be the predictors of C limitation at surface soils. These findings suggest that long-term N deposition may drive varied biogeochemical consequences across distinct soil horizons, and it is necessary to consider depth-depe...