Stratospheric microbiology at 20 km over the Pacific Ocean
An aerobiology sampling flight at 20 km was conducted on 28 April 2008 over the Pacific Ocean (36.5° N, 118–149° W), a period of time that coincided with the movement of Asian dust across the ocean. The aim of this study was to confirm the presence of viable bacteria and fungi within a transoceanic, atmospheric bridge and to improve the resolution of flight hardware processing techniques. Isolates of the microbial strains recovered were analyzed with ribosomal ribonucleic acid (rRNA) sequencing to identify bacterial species Bacillus sp., Bacillus subtilis,Bacillus endophyticus, and the fungal genus Penicillium. Satellite imagery and ground-based radiosonde observations were used to measure dust movement and characterize the high-altitude environment at the time of collection. Considering the atmospheric residency time (7–10 days), the extreme temperature regime of the environment (−75°C), and the absence of a mechanism that could sustain particulates at high altitude, it is unlikely that our samples indicate a permanent, stratospheric ecosystem. However, the presence of viable fungi and bacteria in transoceanic stratosphere remains relevant to understanding the distribution and extent of microbial life on Earth.
KeywordsUpper atmosphere Stratosphere Microbiology Pacific Ocean
- Bauman, J. J., Russell, P. B., Geller, M. A., & Hamill, P. (2003). A stratospheric aerosol climatology from SAGE II and CLAES measurements: 2. Results and comparisons, 1984–1999. Journal of Geophysical Research, 108(D 13), 1–30.Google Scholar
- Brasseur, G., & Solomon, S. (1986). Aeronomy of the middle atmosphere (2nd ed.). Dordrecht: D. Reidel Publishing Company.Google Scholar
- Hamilton, W. D., & Lenton, T. M. (1998). Spora and Gaia: How microbes fly with their clouds. Ethology Ecology & Evolution, 10, 1–16.Google Scholar
- Imshenetsky, A. A., Lysenko, S. V., & Kazakov, G. A. (1978). Upper boundary of the biosphere. Applied and Environmental Microbiology, 35(1), 1–5.Google Scholar
- Lysenko, S. V. (1980). Resistance of microorganisms of upper layers of the atmosphere to ultraviolet radiation and a high vacuum. Mikrobiologiia, 49(1), 175–177 (in Russian).Google Scholar
- Lysenko, S. V., & Demina, N. S. (1992). Drying as one of the extreme factors for the microflora of the atmosphere. Journal of the British Interplanetary Society, 45, 39.Google Scholar
- Nadkarni, M. A., Martin, F. E., Jacques, N. A., & Hunter, N. (2002). Determination of bacterial load by real-time PCR using a broad-range (universal) probe and primers set. Microbiology, 148, 257–266.Google Scholar
- National Science Foundation (NSF), NASA Successfully Flight-Test New Balloon Over Antarctica. 26 January 2008. http://www.nsf.gov/news/news_summ.jsp?cntn_id=112956&org=NSF&from=news
- Pratt, K. A., DeMott, P. J., French, J. F., Wang, Z., Westphal, D. L., Heymsfield, A. J., et al. (2009). In-situ detection of biological particles in cloud ice-crystals. Nature Geoscience. doi:10.1038/NGEO521. Published online 17 May 2009.
- Prenni, A. J., Petters, M. D., Kreidenweis, S. M., Heald, C. L., Martin, S. T., Artaxo, P., et al. (2009). Relative roles of biogenic emissions and Saharan dust as ice nuclei in the Amazon basin. Nature Geosciences. doi:10.1038/NGEO517. Published online 3 May 2009.
- Shivaji, S., Chaturvedi, P., Suresh, K., Reddy, G. S. N., Dutt, C. B. S., Wainwright, M., et al. (2006). Bacillus aerius sp. nov., Bacillus aerophilus sp. nov., Bacillus stratosphericus sp. nov. and Bacillus altitudinis sp. nov., isolated from cryogenic tubes used for collecting air samples from high altitudes. International Journal of Systematic and Evolutionary Microbiology, 56, 1465–1473.CrossRefGoogle Scholar
- Wainwright, M., Wickramasinghe, N. C., Narlikar, J. V., & Rajaratnam, P. (2002). Microorganisms culture from stratospheric air samples obtained at 41 km. FEMS Microbiology Letters, 10778, 1–5.Google Scholar
- White, T. J., Bruns, T. D., Lee, S. B., & Taylor, J. W. (1990). Amplification and direct sequencing of fungal ribosomal RNA genes for phylogenetics. In M. A. Innis, D. H. Gelfand, J. J. Sninsky, & T. J. White (Eds.), PCR protocols: A guide to methods and applications (pp. 315–322). London: Academic Press.Google Scholar