Air-dried soils for microbial biogeography

The potential of archived air-dried soil samples to enhance our understanding of long-term microbial community dynamics remains largely untapped due to concerns about their reliability for molecular analyses. While previous studies have investigated air-drying effects on soil microbial analysis, few have examined these effects across diverse environmental gradients, limiting our understanding of archived soil samples in microbial biogeography at large spatial scales. Through a comprehensive regional survey of 244 arable sites in eastern China, we evaluated the impact of air-drying on microbial biogeographical analysis. Our results demonstrate that while air-drying significantly altered community composition and diversity metrics, it preserved broad ecological patterns and environmental relationships. Air-dried samples maintained similar community dissimilarity patterns and environmental drivers as fresh samples, despite showing reduced diversity and shifted taxonomic compositions. Co-occurrence network analysis revealed altered correlation patterns, likely due to differential responses to desiccation stress. These findings establish a framework for leveraging air-dried samples in microbial ecology, particularly for large-scale studies focused on microbial biogeography and environmental relationships, while providing practical guidelines for results interpretation.

由于担忧存档风干土壤样品（archived air-dried soil samples）用于分子分析（molecular analyses）的可靠性，其在加深我们对长期微生物群落动态理解方面的潜力迄今仍未得到充分发掘。尽管已有前人研究探讨了风干处理对土壤微生物分析的影响，但极少有研究在多样环境梯度下开展此类探索，这限制了我们在大空间尺度上对存档土壤样品在微生物生物地理学（microbial biogeography）中应用的认知。本研究针对中国东部244个耕地样点开展了全面的区域调查，以此评估风干处理对微生物生物地理学分析的影响。研究结果表明，尽管风干处理显著改变了群落组成与多样性指标，但它仍保留了宏观生态格局与环境关联的整体特征。尽管风干样品的多样性有所降低、类群组成发生偏移，但其群落相异模式与环境驱动因子与新鲜样品保持一致。共现网络分析（co-occurrence network analysis）揭示了群落关联模式的改变，这可能源于不同类群对干燥胁迫（desiccation stress）的响应差异。本研究的发现为利用风干样品开展微生物生态学研究搭建了理论框架，尤其适用于聚焦微生物生物地理学与环境关联的大尺度研究，同时也为研究结果的解读提供了实用指导。