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| Titel |
Suspendable macromolecules are responsible for ice nucleation activity of birch and conifer pollen |
| VerfasserIn |
B. G. Pummer, H. Bauer, J. Bernardi, S. Bleicher, H. Grothe |
| 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. 5 ; Nr. 12, no. 5 (2012-03-07), S.2541-2550 |
| Datensatznummer |
250010861
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| Publikation (Nr.) |
 copernicus.org/acp-12-2541-2012.pdf |
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| Zusammenfassung |
| The ice nucleation of bioaerosols (bacteria, pollen, spores, etc.) is a
topic of growing interest, since their impact on ice cloud formation and
thus on radiative forcing, an important parameter in global climate, is not
yet fully understood. Here we show that pollen of different species strongly
differ in their ice nucleation behaviour. The average freezing temperatures
in laboratory experiments range from 240 to 255 K. As the most efficient
nuclei (silver birch, Scots pine and common juniper pollen) have a
distribution area up to the Northern timberline, their ice nucleation
activity might be a cryoprotective mechanism. Far more intriguingly, it has
turned out that water, which has been in contact with pollen and then been
separated from the bodies, nucleates as good as the pollen grains
themselves. The ice nuclei have to be easily-suspendable macromolecules
located on the pollen. Once extracted, they can be distributed further
through the atmosphere than the heavy pollen grains and so presumably
augment the impact of pollen on ice cloud formation even in the upper
troposphere. Our experiments lead to the conclusion that pollen ice nuclei,
in contrast to bacterial and fungal ice nucleating proteins, are
non-proteinaceous compounds. |
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