Yang Yang, Gunina Anna, Chen Ji, Wang Baorong, Cheng Huan, Wang Yunqiang, Liang Chao, An Shaoshan, Chang Scott X
State Key Laboratory of Loess Science, Institute of Earth Environment, Chinese Academy of Sciences, Xi'an, China.
National Observation and Research Station of Earth Critical Zone on the Loess Plateau, Xi'an, Shaanxi, China.
Glob Chang Biol. 2025 Jun;31(6):e70292. doi: 10.1111/gcb.70292.
Microorganisms are the main drivers of soil organic carbon (SOC) formation, especially through the accumulation of microbial necromass C. It is unclear, however, how microorganisms mediate the accumulation of necromass in soil because microbial communities are prohibitively diverse. To bridge this knowledge gap, biomarkers of microbial cell walls (amino sugars) were combined with high-throughput sequencing, spanning a 900 km climatic gradient through the Loess Plateau. The cropland and three restoration types (grassland, shrubland, and forestland) were included, and 291 samples were collected. Necromass C, microbial diversity, and enzyme activities showed the same trend after vegetation restoration (from cropland to forestland). Soil pH, clay, microbial biomass C, and α-1,4-glucosidase were the strong predictors for both bacterial and fungal necromass C. There was a strong positive linear relationship that existed between bacterial necromass C and diversity and also between fungal necromass C and diversity (p < 0.01), pointing to the strong links between microbial diversities and residues. Specifically, necromass C was strongly correlated with dominant microbial taxa, suggesting that these taxa might control the variation of necromass and other metabolic residues. The relative abundances of Actinobacteria, Proteobacteria, and Bacteroidetes gradually increased after vegetation restoration, and changed from oligotrophic to copiotrophic groups. It means that vegetation restoration promoted opportunistic and resilient microbial taxa that may have copiotrophic or fast-response characteristics to increase the accumulation of necromass C and potentially contribute to soil C sequestration in these systems. In this regard, vegetation restoration governs SOC storage by shaping the unique dominant microbial communities, facilitating the accumulation of necromass C. This research enhances our understanding of the survival strategies of microbial life and suggests greater contribution to necromass than previously recognized for soil microbiomes.
微生物是土壤有机碳（SOC）形成的主要驱动因素，特别是通过微生物残体碳的积累。然而，目前尚不清楚微生物如何介导土壤中残体的积累，因为微生物群落的多样性极高。为了填补这一知识空白，将微生物细胞壁的生物标志物（氨基糖）与高通量测序相结合，跨越黄土高原900公里的气候梯度。研究涵盖了农田和三种恢复类型（草地、灌丛地和林地），共采集了291个样本。植被恢复后（从农田到林地），残体碳、微生物多样性和酶活性呈现相同的趋势。土壤pH值、黏土、微生物生物量碳和α-1,4-葡萄糖苷酶是细菌和真菌残体碳的有力预测指标。细菌残体碳与多样性之间以及真菌残体碳与多样性之间存在很强的正线性关系（p < 0.01），这表明微生物多样性与残体之间存在紧密联系。具体而言，残体碳与优势微生物类群密切相关，这表明这些类群可能控制着残体和其他代谢产物的变化。植被恢复后，放线菌、变形菌和拟杆菌的相对丰度逐渐增加，并从贫营养型转变为富营养型。这意味着植被恢复促进了具有机会主义和适应性的微生物类群，这些类群可能具有富营养或快速响应的特性，从而增加了残体碳的积累，并可能有助于这些系统中的土壤碳固存。在这方面，植被恢复通过塑造独特的优势微生物群落来控制土壤有机碳的储存，促进残体碳的积累。这项研究增进了我们对微生物生存策略的理解，并表明土壤微生物群对残体的贡献比之前认识到的更大。
