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| Titel |
Coupling of fog and marine microbial content in the near-shore coastal environment |
| VerfasserIn |
M. E. Dueker, G. D. O'Mullan, K. C. Weathers, A. R. Juhl, M. Uriarte |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1726-4170
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| Digitales Dokument |
URL |
| Erschienen |
In: Biogeosciences ; 9, no. 2 ; Nr. 9, no. 2 (2012-02-17), S.803-813 |
| Datensatznummer |
250006768
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| Publikation (Nr.) |
 copernicus.org/bg-9-803-2012.pdf |
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| Zusammenfassung |
| Microbes in the atmosphere (microbial aerosols) play an important role in
climate and provide an ecological and biogeochemical connection between
oceanic, atmospheric, and terrestrial environments. However, the sources and
environmental factors controlling the concentration, diversity, transport,
and viability of microbial aerosols are poorly understood. This study
examined culturable microbial aerosols from a coastal environment in Maine
(USA) and determined the effect of onshore wind speed and fog presence on
deposition rate, source, and community composition. During fog events with
low onshore winds (<2 m s−1) the near-shore deposition of microbial
aerosols (microbial fallout) decreased with increasing wind speeds, whereas
microbial fallout rates under clear conditions and comparable low wind
speeds showed no wind speed dependence. Mean aerosol particle size also
increased with onshore wind speed when fog was present, indicating increased
shoreward transport of larger aerosol particles. 16S rRNA sequencing of
culturable ocean surface bacteria and microbial aerosols deposited onshore
resulted in the detection of 31 bacterial genera, with 5 dominant genera
(Vibrio, Bacillus, Pseudoalteromonas, Psychrobacter, Salinibacterium) making up 66 % of all sequences. The sequence library from microbial
aerosol isolates, as with libraries found in other coastal/marine aerosol
studies, was dominated at the phylum level by Proteobacteria, with
additional representation from Firmicutes, Actinobacteria and Bacteroidetes.
Seventy-five percent of the culturable microbial aerosols falling out under
foggy conditions were most similar to GenBank-published sequences detected
in marine environments. Using a 97 % similarity cut-off, sequence
libraries from ocean surface and fog isolates shared eight operational
taxonomic units (OTU's) in total, three of which were the most dominant
OTU's in the library, representing large fractions of the ocean (28 %) and
fog (21 %) libraries. The fog and ocean surface libraries were
significantly more similar in microbial community composition than clear
(non-foggy) and ocean surface libraries, according to both Jaccard and
Sorenson indices. These findings provide the first evidence of a difference
in community composition and microbial culturability of aerosols associated
with fog compared to clear conditions. The data support a dual role for fog
in enhancing the fallout of viable microbial aerosols via increased
gravitational settling rates and decreased aerosolization stress on the
organisms, which may include relief from UV inactivation, desiccation, and
oligotrophic microconditions. This study provides a strong case for ocean to
terrestrial transport of microbes and a potential connection between water
quality and air quality at coastal sites. |
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