Microbial traits drive soil priming effect in response to nitrogen addition along an alpine forest elevation gradient

• Published in: The Science of the total environment 2024-01, Vol.907, p.167970-167970, Article 167970
• Main Authors: Ma, Tiantian, Zhan, Yabin, Chen, Wenjie, Hou, Zhuonan, Chai, Shengyang, Zhang, Junling, Zhang, Xinjun, Wang, Ruihong, Liu, Rui, Wei, Yuquan
• Format: Article
• Language: English
• Subjects: altitude; bioinformatics; China; climate; ecosystems; Elevational patterns; Enzyme activities; equations; forests; fungi; global change; glucose; Microbial co-occurrence network; microbial communities; mineralization; nitrogen; Nitrogen availability; Priming effect; soil; soil organic carbon; Tibetan Plateau; total nitrogen
• ISSN: 0048-9697; 1879-1026
• DOI: 10.1016/j.scitotenv.2023.167970

Priming effect is a critical process affecting soil organic carbon (SOC) cycle, however, its drivers and patterns responding to nutrient addition are still unclear in alpine forests. Here, we conducted a 28-day incubation experiment based on the collected soils along an elevational gradient (3500–4300 m) on the southeastern Tibetan Plateau with adding carbon and nitrogen sources. The priming effect and microbial traits were analyzed based on 13C-stable glucose and bioinformatics methods. Results revealed that the carbon priming effect (PEC) ranged from 0.45 to 1.63 mg C g−1 SOC along the altitude, which was significantly associated with both soil organic carbon and total nitrogen. The addition of nitrogen inhibited the PEC and showed a positive correlation with the activities of β-1,4-glucosidase, β-1,4-N-acetyl-glucosaminnidase, β-cellobiosidase and β-xylosidase, while microbial community network became more complex and stable in respond to nitrogen addition. Structural equation modeling indicated that microbial communities, especially fungal communities in alpine regions drove PEC in response to nitrogen addition. Soil enzymes were the important intermediaries which drove the mineralization of soil carbon by microorganisms after adding nitrogen. Microorganisms were more sensitive to nitrogen rather than carbon due to the specific climate of alpine regions. Collectively, our works revealed the response pattern of soil carbon decomposition to nutrient addition in alpine ecosystem, clarifying the contribution of soil microorganisms in regulating carbon decomposition and nutrient cycle along high-elevation gradients in the context of global environmental change. [Display omitted] •Carbon PE increased along an alpine forest elevation gradient (3500–4300 m).•The intensity of carbon PE varied along the altitude mainly affected by SOC and TN.•N addition inhibited the carbon PE and caused more complex microbial community.•Microbial especially fungal communities drove carbon PE in response to N addition.•Soil microbes at Mount Segrila were more sensitive to N availability rather than C.