Coastal salt marshes are key sites of biogeochemical cycling and ideal systems in which to investigate the community structure of complex microbial communities. Here, we clarify structural-functional relationships among microorganisms and their mineralogical environment, revealing previously undescribed metabolic activity patterns and precise spatial arrangements within salt marsh sediment. Following 3.7-day in situ incubations with a non-canonical amino acid that was incorporated into new biomass, samples were embedded and analyzed by correlative fluorescence and electron microscopy to map the microscale arrangements of anabolically active and inactive organisms alongside mineral grains. Parallel sediment samples were examined by fluorescence-activated cell sorting and 16S rRNA gene sequencing to link anabolic activity to taxonomic identity. Both approaches demonstrated a rapid decline in the proportion of anabolically active cells with depth into salt marsh sediment, from ~60% in the top cm to 10-25% between 2-7 cm. From the top to the bottom, the most prominent active community members shifted from sulfur cycling phototrophic consortia, to sulfate-reducing bacteria likely oxidizing organic compounds, to fermentative lineages. Correlative microscopy revealed more abundant (and more anabolically active) organisms around non-quartz minerals including rutile, orthoclase, and plagioclase. Microbe-mineral relationships appear to be dynamic and context-dependent arbiters of biogeochemical cycling.

中文翻译：

---

空间分辨相关显微镜和微生物鉴定揭示了盐沼沉积物中动态的依赖深度和矿物质的合成代谢活性

沿海盐沼是生物地球化学循环的关键场所，也是研究复杂微生物群落结构的理想系统。在这里，我们阐明了微生物与其矿物环境之间的结构-功能关系，揭示了盐沼沉积物中先前未描述的代谢活动模式和精确的空间排列。用掺入新生物质中的非规范氨基酸原位孵育3.7天后，将样品包埋并通过相关荧光和电子显微镜进行分析，以绘制无代谢活性和无活性生物与矿物质颗粒的微观排列。通过荧光激活细胞分选和16S rRNA基因测序检查平行沉淀物样品，以将合成代谢活性与分类学身份联系起来。两种方法都表明，进入盐沼沉积物的深度，合成代谢活跃细胞的比例迅速下降，从顶厘米的60％降至2-7厘米之间的10-25％。从上到下，最杰出的活跃社区成员从硫循环的光养联盟转移到了硫酸盐还原细菌，可能氧化了有机化合物，再到了发酵谱系。相关显微镜检查显示，在非石英矿物质（包括金红石，正长石和斜长石）周围有更多的生物（具有更多的代谢活性）。微生物-矿物关系似乎是生物地球化学循环的动态和上下文相关的仲裁者。从上到下，最杰出的活跃社区成员从硫循环的光养联盟转移到了硫酸盐还原细菌，可能氧化了有机化合物，再到了发酵谱系。相关显微镜检查显示，在非石英矿物质（包括金红石，正长石和斜长石）周围有更多的生物（具有更多的代谢活性）。微生物-矿物关系似乎是生物地球化学循环的动态和上下文相关的仲裁者。从上到下，最杰出的活跃社区成员从硫循环的光养联盟转移到了硫酸盐还原细菌，可能氧化了有机化合物，再到了发酵谱系。相关显微镜检查显示，在非石英矿物质（包括金红石，正长石和斜长石）周围有更多的生物（具有更多的代谢活性）。微生物-矿物关系似乎是生物地球化学循环的动态和上下文相关的仲裁者。