Bacterial growth in cloud droplets

Updated 2003-07-21

It is well known that the atmosphere is a conveyor of microorganisms, and that bacteria can act as ice or cloud condensation nuclei, but clouds have not been considered as a site where organisms can live and reproduce. We could show that bacteria in cloud droplets collected at high altitudes are actively growing and reproducing at temperatures at or below 0°C. Since ~60% of the earth surface is covered by clouds, cloud water should be considered as a microbial habitat.

Time frame

Project time span
1997 - 1998
Data collection
1997 - 1998
Data processing
1998 - 2000
Data reporting
2000 - 2002

Contact information

Contact person
B. Sattler
University of Innsbruck Institute of Zoology and Limnology Technikerstrasse 25 6020 Innsbruck Austria
Other project contacts
Roland Psenner, University of Innsbruck, Institute of Zoology and Limnology Hans Puxbaum, Vienna University of Technology, Institute of Analytical Chemistry, Getreidemarkt 9/151, 1060 Vienna, Austria

Parameters and Media

Parameter groups measured/observed/modelled
Biological effects
Media sampled/studied/modelled
Additional information or further specification of types of data / information collected, species / tissues / organs sampled, etc.



Regions studied
Biological effects
Biological effects

Data availability

References to key publications (or planned publications) and data reports
Sattler, B., Puxbaum, H., and Psenner, R. 2001. Bacterial growth in supercooled cloud droplets. Geophysical Research Letters 28(2):239-242 (published as highlight) Psenner, R., A. Wille, J. Priscu, M. Felip, D. Wagenbach, and B. Sattler. 2002. Low Temperature Environments and Biodiversity. Contribution to UNESCO-Extremophiles. Sattler B., H. Puxbaum, and R. Psenner. Bakterien der Lüfte. Vom Winde verweht. Biologie in unserer Zeit 32: 42-49, 2002. Titelstory Sattler, B., H. Puxbaum, A. Limbeck, and R. Psenner. Clouds as habitat and seeders of bacteria. The International Society For Optical Engineering. Proceedings. Instruments, Methods, and Missions for Astrobiology IV. SPIE 4495:211-222, 2002.
Samples/specimens archived in specimen banks?

Methods & Procedures

Procedures and methodology used for, e.g., sampling and sample storage, sample pretreatment, extraction and analysis, including which laboratories are involved, references to methods employed, etc.

sampling conducted by Vienna University of Technology cryotransport to University of Innsbruck main methods: epifluorescence microscopy radiochemical uptake of radioactive labelled tracers (3H-thymidine and 14C-leucine incorporation to measure bacterial activity)

Additional Information

Is this a bi- AND multi-lateral project (i.e. a project involving cooperation between different countries)?
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