Subsurface microorganisms make up the majority of Earth's microbial biomass, but ecological processes governing surface communities may not explain community patterns at depth because of burial. Depth constrains dispersal and energy availability, and when combined with geographic isolation across landscapes, may influence community assembly. We sequenced the 16S rRNA gene of bacteria and archaea from 48 sediment cores across 36 lakes in four disconnected mountain ranges in Wyoming, USA and used null models to infer assembly processes across depth, spatial isolation, and varying environments. Although we expected strong dispersal limitations across these isolated settings, community composition was primarily shaped by environmental selection. Communities consistently shifted from domination by organisms that degrade organic matter at the surface to methanogenic, low‐energy adapted taxa in deeper zones. Stochastic processes—like dispersal limitation—contributed to differences among lakes, but because these effects weakened with depth, selection processes ultimately governed subsurface microbial biogeography.

中文翻译：

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环境过滤控制着不相连的高山湖泊沉积微生物群落的一致垂直分区

地下微生物构成了地球微生物生物量的大部分，但由于埋藏，控制地表群落的生态过程可能无法解释深层群落模式。深度限制了分散和能源可用性，当与跨景观的地理隔离相结合时，可能会影响群落的聚集。我们对美国怀俄明州四个不相连的山脉中 36 个湖泊的 48 个沉积物核心中的细菌和古细菌的 16S rRNA 基因进行了测序，并使用零模型来推断跨深度、空间隔离和不同环境的组装过程。尽管我们预计这些孤立环境中的传播会受到很大的限制，但群落组成主要是由环境选择决定的。群落不断从降解地表有机物的生物体占主导地位转向更深区域的产甲烷、低能量适应类群。随机过程（如扩散限制）导致了湖泊之间的差异，但由于这些影响随着深度而减弱，选择过程最终控制了地下微生物的生物地理学。