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| Titel |
Ice nucleation by fungal spores from the classes Agaricomycetes, Ustilaginomycetes, and Eurotiomycetes, and the effect on the atmospheric transport of these spores |
| VerfasserIn |
D. I. Haga, S. M. Burrows, R. Iannone, M. J. Wheeler, R. H. Mason, J. Chen, E. A. Polishchuk, U. Pöschl, A. K. Bertram |
| 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 ; 14, no. 16 ; Nr. 14, no. 16 (2014-08-26), S.8611-8630 |
| Datensatznummer |
250118974
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| Publikation (Nr.) |
 copernicus.org/acp-14-8611-2014.pdf |
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| Zusammenfassung |
| We studied the ice nucleation properties of 12 different species of fungal
spores chosen from three classes: Agaricomycetes,
Ustilaginomycetes, and Eurotiomycetes.
Agaricomycetes include many types of mushroom species and are widely
distributed over the globe. Ustilaginomycetes are agricultural
pathogens and have caused widespread damage to crops. Eurotiomycetes
are found on all types of decaying material and include important human
allergens. We focused on these classes because they are thought to be
abundant in the atmosphere and because there is very little information on
the ice nucleation ability of these classes of spores in the literature. All
of the fungal spores investigated contained some fraction of spores that
serve as ice nuclei at temperatures warmer than homogeneous freezing. The
cumulative number of ice nuclei per spore was 0.001 at temperatures between
−19 °C and −29 °C, 0.01 between −25.5 °C and
−31 °C, and 0.1 between −26 °C and −31.5 °C.
On average, the order of ice nucleating ability for these spores is
Ustilaginomycetes
> Agaricomycetes ≃ Eurotiomycetes. The
freezing data also suggests that, at temperatures ranging from
−20 °C to −25 °C, all of the fungal spores studied here
are less efficient ice nuclei compared to Asian mineral dust on a per surface
area basis. We used our new freezing results together with data in the
literature to compare the freezing temperatures of spores from the phyla
Basidiomycota and Ascomycota, which together make up
98% of known fungal species found on Earth. The data show that within
both phyla (Ascomycota and Basidiomycota), there is a wide
range of freezing properties, and also that the variation within a phylum is
greater than the variation between the average freezing properties of the
phyla. Using a global chemistry–climate transport model, we investigated
whether ice nucleation on the studied spores, followed by precipitation, can
influence the transport and global distributions of these spores in the
atmosphere. Simulations suggest that inclusion of ice nucleation scavenging
of these fungal spores in mixed-phase clouds can decrease the annual mean
concentrations of fungal spores in near-surface air over the oceans and polar
regions, and decrease annual mean concentrations in the upper troposphere. |
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