Climate warming alters the relative importance of plant root and microbial community in regulating the accumulation of soil microbial necromass carbon in a Tibetan alpine meadow

• Published in: Global change biology 2023-06, Vol.29 (11), p.3193-3204
• Main Authors: Cai, Mengke, Zhao, Guang, Zhao, Bo, Cong, Nan, Zheng, Zhoutao, Zhu, Juntao, Duan, Xiaoqing, Zhang, Yangjian
• Format: Article
• Language: English
• Subjects: Accumulation; alpine meadow; belowground carbon input; Carbon; Carbon - analysis; Carbon capture and storage; Carbon sequestration; Climate; Climate change; Climate prediction; climate warming; Global warming; Grassland; Mathematical models; Meadows; microbial necromass carbon; Microbiomes; Microbiota; Microorganisms; Multivariate statistical analysis; Organic carbon; Organic soils; Plant roots; Plant Roots - chemistry; Soil; Soil - chemistry; soil C‐climate feedback; Soil layers; Soil Microbiology; Soils; Tibet
• ISSN: 1354-1013; 1365-2486
• DOI: 10.1111/gcb.16660

Climate warming is predicted to considerably affect variations in soil organic carbon (SOC), especially in alpine ecosystems. Microbial necromass carbon (MNC) is an important contributor to stable soil organic carbon pools. However, accumulation and persistence of soil MNC across a gradient of warming are still poorly understood. An 8‐year field experiment with four levels of warming was conducted in a Tibetan meadow. We found that low‐level (+0–1.5°C) warming mostly enhanced bacterial necromass carbon (BNC), fungal necromass carbon (FNC), and total MNC compared with control treatment across soil layers, while no significant effect was caused between high‐level (+1.5–2.5°C) treatments and control treatments. The contributions of both MNC and BNC to soil organic carbon were not significantly affected by warming treatments across depths. Structural equation modeling analysis demonstrated that the effect of plant root traits on MNC persistence strengthened with warming intensity, while the influence of microbial community characteristics waned along strengthened warming. Overall, our study provides novel evidence that the major determinants of MNC production and stabilization may vary with warming magnitude in alpine meadows. This finding is critical for updating our knowledge on soil carbon storage in response to climate warming. High‐level warming weakened the contribution of MNC to soil organic carbon. Plant root carbon input may play a more important role in MNC formation and stabilization than microbial community characteristics do.