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| Titel |
Effects of atmospheric conditions on ice nucleation activity of Pseudomonas |
| VerfasserIn |
E. Attard, H. Yang, A.-M. Delort, P. Amato, U. Pöschl, C. Glaux, T. Koop, C. E. Morris |
| 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 ; 12, no. 22 ; Nr. 12, no. 22 (2012-11-16), S.10667-10677 |
| Datensatznummer |
250011590
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| Publikation (Nr.) |
 copernicus.org/acp-12-10667-2012.pdf |
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| Zusammenfassung |
| Although ice nuclei from bacterial origin are known to be efficient at the
highest temperatures known for ice catalysts, quantitative data are still
needed to assess their role in cloud processes. Here we studied the effects
of three typical cloud conditions (i) acidic pH (ii) NO2 and O3
exposure and (iii) UV-A exposure on the ice nucleation activity (INA) of four
Pseudomonas strains. Three of the Pseudomonas syringae
strains were isolated from cloud water and the phyllosphere
and Pseudomonas fluorescens strain CGina-01 was isolated from
Antarctic glacier ice melt. Among the three conditions tested, acidic pH
caused the most significant effects on INA likely due to denaturation of the
ice nucleation protein complex. Exposure to NO2 and O3 gases had no
significant or only weak effects on the INA of two P. syringae
strains whereas the INA of P. fluorescens CGina-01 was significantly
affected. The INA of the third P. syringae strain showed variable
responses to NO2 and O3 exposure. These differences in the INA of
different Pseudomonas suggest that the response to atmospheric
conditions could be strain-specific. After UV-A exposure, a substantial loss
of viability of all four strains was observed whereas their INA decreased
only slightly. This corroborates the notion that under certain conditions
dead bacterial cells can maintain their INA. Overall, the negative effects of
the three environmental factors on INA were more significant at the warmer
temperatures. Our results suggest that in clouds where temperatures are near
0 °C, the importance of bacterial ice nucleation in precipitation
processes could be reduced by some environmental factors. |
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