Soil–water interfaces (SWI) are biogeochemical hotspots characterized by millimeter-scale redox gradients, indicating that parallel changes are also present in microbial community structure and activity. However, soil-based analyses of microbial community structure typically examine bulk samples and seldom consider variation at a scale relevant to changes in environmental conditions. Here we presented a study that aimed to describe millimeter-scale variance in both microbial community structure and physicochemical properties in a lab flooded soil. At this fine-scale resolution, the stratification of biogeochemical properties (e.g., redox potential, nitrate concentration) was consistent with the structure of the active microbial community with clear shifts in the relative abundance of transcriptionally active populations associated with changing redox conditions. Our results demonstrate that spatial scale should be carefully considered when investigating ecological mechanisms that influence soil microbial community structures.

土壤-水界面（SWI）是以毫米级氧化还原梯度为特征的生物地球化学热点，表明微生物群落结构和活动也存在平行变化。然而，基于土壤的微生物群落结构分析通常检查大量样品，很少考虑与环境条件变化相关的规模变化。在这里，我们提出了一项研究，旨在描述实验室淹没土壤中微生物群落结构和理化性质的毫米级变化。在这种精细分辨率下，生物地球化学特性（例如氧化还原电位、硝酸盐浓度）的分层与活性微生物群落的结构一致，与氧化还原条件变化相关的转录活性群体的相对丰度发生明显变化。我们的结果表明，在研究影响土壤微生物群落结构的生态机制时，应仔细考虑空间尺度。