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| Titel |
Bacteria in the global atmosphere – Part 2: Modeling of emissions and transport between different ecosystems |
| VerfasserIn |
S. M. Burrows, T. Butler, P. Jöckel, H. Tost, A. Kerkweg, U. Pöschl, M. G. Lawrence |
| 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 ; 9, no. 23 ; Nr. 9, no. 23 (2009-12-10), S.9281-9297 |
| Datensatznummer |
250007792
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| Publikation (Nr.) |
 copernicus.org/acp-9-9281-2009.pdf |
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| Zusammenfassung |
| Bacteria are constantly being transported through the atmosphere,
which may have implications for human health, agriculture, cloud
formation, and the dispersal of bacterial species. We simulate the
global transport of bacteria, represented as 1 μm and 3 μm
diameter spherical solid particle tracers in a general circulation
model. We investigate factors influencing residence time and
distribution of the particles, including emission region, cloud
condensation nucleus activity and removal by ice-phase
precipitation. The global distribution depends strongly on the
assumptions made about uptake into cloud droplets and ice. The
transport is also affected, to a lesser extent, by the emission
region, particulate diameter, and season. We find that the seasonal
variation in atmospheric residence time is insufficient to explain
by itself the observed seasonal variation in concentrations of
particulate airborne culturable bacteria, indicating that this
variability is mainly driven by seasonal variations in culturability
and/or emission strength. We examine the potential for exchange of
bacteria between ecosystems and obtain rough estimates of the flux
from each ecosystem by using a maximum likelihood estimation
technique, together with a new compilation of available observations
described in a companion paper. Globally, we estimate the total
emissions of bacteria-containing particles to the atmosphere to be 7.6×1023–3.5×1024 a−1,
originating mainly from
grasslands, shrubs and crops. We estimate the mass of emitted
bacteria- to be 40–1800 Gg a−1, depending on the mass
fraction of bacterial cells in the particles. In order to improve
understanding of this topic, more measurements of the bacterial
content of the air and of the rate of surface-atmosphere exchange of
bacteria will be necessary. Future observations in wetlands, hot
deserts, tundra, remote glacial and coastal regions and over oceans
will be of particular interest. |
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