Flying microbes—survival in the extreme conditions of the stratosphere during a stratospheric balloon flight experiment

Abstract

Earth's stratosphere is a hostile environment that has challenged microbial survival. We set out to test the effect of stratosphere exposure on survival of single species ( Bacillus subtilis ) and complex microbial communities from soils and sediment. B. subtilis survival was strongly impacted by sun exposure, i.e., ultraviolet (UV) radiation, with only 1% survival at full sun exposure. Complex microbial communities had high survival rates, and the soil or sediment matrix may have provided protection against radiation and desiccation, supporting the survival of environmental microorganisms.