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| Titel |
Survival and ice nucleation activity of bacteria as aerosols in a cloud simulation chamber |
| VerfasserIn |
P. Amato, M. Joly, C. Schaupp, E. Attard, O. Möhler, C. E. Morris, Y. Brunet, A.-M. Delort |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1680-7316
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| Digitales Dokument |
URL |
| Erschienen |
In: Atmospheric Chemistry and Physics ; 15, no. 11 ; Nr. 15, no. 11 (2015-06-12), S.6455-6465 |
| Datensatznummer |
250119809
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| Publikation (Nr.) |
 copernicus.org/acp-15-6455-2015.pdf |
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| Zusammenfassung |
| The residence time of bacterial cells in the atmosphere is predictable by
numerical models. However, estimations of their aerial dispersion as living
entities are limited by a lack of information concerning survival rates and
behavior in relation to atmospheric water. Here we investigate the viability
and ice nucleation (IN) activity of typical atmospheric ice nucleation
active bacteria (Pseudomonas syringae and P. fluorescens) when airborne in a cloud simulation chamber (AIDA,
Karlsruhe, Germany). Cell suspensions were sprayed into the chamber and
aerosol samples were collected by impingement at designated times over a
total duration of up to 18 h, and at some occasions after dissipation of
a cloud formed by depressurization. Aerosol concentration was monitored
simultaneously by online instruments. The cultivability of airborne cells
decreased exponentially over time with a half-life time of 250 ± 30 min (about 3.5 to 4.5 h). In contrast, IN activity remained unchanged
for several hours after aerosolization, demonstrating that IN activity was
maintained after cell death. Interestingly, the relative abundance of IN
active cells still airborne in the chamber was strongly decreased after
cloud formation and dissipation. This illustrates the preferential
precipitation of IN active cells by wet processes. Our results indicate that
from 106 cells aerosolized from a surface, one would survive the
average duration of its atmospheric journey estimated at 3.4 days.
Statistically, this corresponds to the emission of 1 cell that achieves
dissemination every ~ 33 min m−2 of
cultivated crops fields, a strong source of airborne bacteria. Based on the
observed survival rates, depending on wind speed, the trajectory endpoint
could be situated several hundreds to thousands of kilometers from the
emission source. These results should improve the representation of the
aerial dissemination of bacteria in numeric models. |
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