, Volume 27, Issue 4, pp 319–332

Microbial survival in the stratosphere and implications for global dispersal


    • Department of Biology and Graduate Program in AstrobiologyUniversity of Washington
  • Dale W. Griffin
    • U.S. Geological Survey
  • Richard D. McPeters
    • NASA Goddard Space Flight Center, Laboratory for Atmospheres
  • Peter D. Ward
    • Department of Biology and Graduate Program in AstrobiologyUniversity of Washington
  • Andrew C. Schuerger
    • Department of Plant Pathology, Space Life Sciences Laboratory, Kennedy Space CenterUniversity of Florida
Original Paper

DOI: 10.1007/s10453-011-9203-5

Cite this article as:
Smith, D.J., Griffin, D.W., McPeters, R.D. et al. Aerobiologia (2011) 27: 319. doi:10.1007/s10453-011-9203-5


Spores of Bacillus subtilis were exposed to a series of stratosphere simulations. In total, five distinct treatments measured the effect of reduced pressure, low temperature, high desiccation, and intense ultraviolet (UV) irradiation on stratosphere-isolated and ground-isolated B. subtilis strains. Environmental conditions were based on springtime data from a mid-latitude region of the lower stratosphere (20 km). Experimentally, each treatment consisted of the following independent or combined conditions: −70°C, 56 mb, 10–12% relative humidity and 0.00421, 5.11, and 54.64 W/m2 of UVC (200–280 nm), UVB (280–315 nm), UVA (315–400 nm), respectively. Bacteria were deposited on metal coupon surfaces in monolayers of ~1 × 106 spores and prepared with palagonite (particle size < 20 μm). After 6 h of exposure to the stratosphere environment, 99.9% of B. subtilis spores were killed due to UV irradiation. In contrast, temperature, desiccation, and pressure simulations without UV had no effect on spore viability up through 96 h. There were no differences in survival between the stratosphere-isolated versus ground-isolated B. subtilis strains. Inactivation of most bacteria in our simulation indicates that the stratosphere can be a critical barrier to long-distance microbial dispersal and that survival in the upper atmosphere may be constrained by UV irradiation.


Stratosphere Natural selection Dispersal Spores Aerobiology

Copyright information

© Springer Science+Business Media B.V. 2011