Airborne Bacterial Communities: Diversity, Survival Strategies and Functional Roles in the Atmosphere

The atmosphere is increasingly recognised as a dynamic microbial habitat, yet the mechanisms that enable bacterial survival in air remain underexplored. This mini-review synthesises current knowledge on airborne bacterial diversity, the selective pressures they face and the traits that support survival. Drawing from environmental surveys, laboratory studies and emerging omics data, we highlight how airborne bacteria survive despite extreme conditions including UV radiation, low water activity, oxidative conditions and limited nutrients. Common traits such as DNA repair, pigmentation, antioxidant systems and spore formation are discussed in relation to atmospheric stress. We also review recent evidence of microbial activity and function in air. By integrating ecological patterns with physiological adaptations, this review outlines how specific traits may contribute to survival in the atmosphere and suggests future directions for functional studies in diverse atmospheric environments.