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Background and aims <p>Nitrogen (N) deposition significantly alters litter decomposition rates, carbon (C) cycling, and nutrient release, modifying soil C—N transformation efficiency. This study investigates the microbial regulation of decomposition, elucidating how N deposition drives decomposition through microbial functional groups and enzyme activities. The findings provide critical insights for predicting forest ecosystem biogeochemical cycles and functional stability under global change.</p> Methods <p>To address global N deposition impacts, we combined in leaf and twig decomposition with N deposition treatments. Through stoichiometric analysis of C, N, phosphorus (P), and potassium (K) dynamics, enzymatic assays (cellulase and polyphenol oxidase) to evaluate decomposition pathways, and 16S rRNA amplicon sequencing to characterize microbial communities, offering a multidimensional perspective on how N deposition reshapes litter decomposition through microbial—enzyme—substrate interactions and revealing novel insights into ecosystem responses to anthropogenic N inputs.</p> Results <p>High N deposition suppressed C, N and P release from decomposing litter and enhanced K release in twigs but inhibited it in leaves, highlighting litter—type—specific responses. High N levels decreased soil cellulase and polyphenol oxidase activities, likely due to N—induced enzyme suppression or substrate competition, slowing organic matter breakdown. Dominant decomposers (Acidobacteria bacteria and Ascomycota fungi) decreased under high N, impairing their ability to drive decomposition. Reduced soil enzyme activity under the influence of N deposition, coupled with restructuring of microbial communities, led to inefficient organic matter turnover.</p> Conclusions <p>High N deposition may limit plant growth by reducing nutrient release, which can decrease future litter inputs and change ecosystem C storage, and it controls decomposition via stoichiometric changes and microbial—enzyme interactions, while the decline of lignin/cellulose—degrading microbes and enzymes under high N indicates a long—term slowdown in decomposition that impacts forest nutrient cycling and C sequestration.</p> Graphical Abstract <p></p>

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N deposition affects litter decomposition in evergreen broad-leaf forests by reducing soil enzyme activities and altering the structure of microbial communities

  • 期刊论文

  • 发表日期：

    2025年6月18日

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  • Jinmei Xing,
  • Wen Chen,
  • Chenggong Song,
  • Xiaodong Li,
  • Qian Wang,
  • Yali Song

摘要

Background and aims

Nitrogen (N) deposition significantly alters litter decomposition rates, carbon (C) cycling, and nutrient release, modifying soil C—N transformation efficiency. This study investigates the microbial regulation of decomposition, elucidating how N deposition drives decomposition through microbial functional groups and enzyme activities. The findings provide critical insights for predicting forest ecosystem biogeochemical cycles and functional stability under global change.

Methods

To address global N deposition impacts, we combined in leaf and twig decomposition with N deposition treatments. Through stoichiometric analysis of C, N, phosphorus (P), and potassium (K) dynamics, enzymatic assays (cellulase and polyphenol oxidase) to evaluate decomposition pathways, and 16S rRNA amplicon sequencing to characterize microbial communities, offering a multidimensional perspective on how N deposition reshapes litter decomposition through microbial—enzyme—substrate interactions and revealing novel insights into ecosystem responses to anthropogenic N inputs.

Results

High N deposition suppressed C, N and P release from decomposing litter and enhanced K release in twigs but inhibited it in leaves, highlighting litter—type—specific responses. High N levels decreased soil cellulase and polyphenol oxidase activities, likely due to N—induced enzyme suppression or substrate competition, slowing organic matter breakdown. Dominant decomposers (Acidobacteria bacteria and Ascomycota fungi) decreased under high N, impairing their ability to drive decomposition. Reduced soil enzyme activity under the influence of N deposition, coupled with restructuring of microbial communities, led to inefficient organic matter turnover.

Conclusions

High N deposition may limit plant growth by reducing nutrient release, which can decrease future litter inputs and change ecosystem C storage, and it controls decomposition via stoichiometric changes and microbial—enzyme interactions, while the decline of lignin/cellulose—degrading microbes and enzymes under high N indicates a long—term slowdown in decomposition that impacts forest nutrient cycling and C sequestration.

Graphical Abstract