Controlled near-space exposure induces community restructuring in an ocean water microbiome

Abstract

Marine microbiomes may experience extreme environmental stress during atmospheric transport, yet how near-space conditions reshape natural microbial communities remains poorly understood. Here, we investigated the effects of controlled near-space exposure on a seawater microbiome using high-altitude balloon experiments and 16S rRNA amplicon sequencing. While alpha diversity remained relatively stable across exposure conditions, weighted UniFrac and PERMANOVA analyses revealed reproducible shifts in microbial community composition associated with flight exposure. Taxonomic profiling demonstrated coordinated restructuring across multiple microbial lineages rather than dominance of a single taxon-specific response. Comparable beta-dispersion among groups supported the robustness of these compositional differences. Together, these findings demonstrate that near-space exposure was associated with reproducible restructuring of microbial community composition without substantial loss of overall diversity. Raw sequencing data have been deposited in the NCBI Sequence Read Archive under BioProject accession PRJNA1479017.