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| Titel |
Microbial food web dynamics in response to a Saharan dust event: results from a mesocosm study in the oligotrophic Mediterranean Sea |
| VerfasserIn |
E. Pulido-Villena, A.-C. Baudoux, I. Obernosterer, M. Landa, J. Caparros, P. Catala, C. Georges, J. Harmand, C. Guieu |
| 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 ; 11, no. 19 ; Nr. 11, no. 19 (2014-10-14), S.5607-5619 |
| Datensatznummer |
250117638
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| Publikation (Nr.) |
 copernicus.org/bg-11-5607-2014.pdf |
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| Zusammenfassung |
| The significant impact of dust deposition on heterotrophic bacterial
dynamics in the surface oligotrophic ocean has recently been evidenced.
Considering the central role of bacteria in the microbial loop, it is likely
that dust deposition also affects the structure and the functioning of the
whole microbial food web. In the frame of the DUNE project, aiming to
estimate the impact of dust deposition on the oligotrophic Mediterranean Sea
through mesocosm experiments, the main goal of the present paper was to
assess how two successive dust deposition events affect the dynamics of the
microbial food web. The first dust seeding delivered new P and N to the
amended mesocosms and resulted in a pronounced stimulation of bacterial
respiration. It also induced pronounced, but transient, changes in the
bacterial community composition. No significant effects were observed on the
abundances of viruses and heterotrophic nanoflagellates. The second dust
seeding also delivered new P and N to the amended mesocosms, but the effect
on the microbial food web was very different. Bacterial respiration remained
constant and bacterial abundance decreased. Compositional changes following
the second seeding were minor compared to the first one. The decrease in
bacterial abundance coincided with an increase in virus abundance, resulting
in higher virus:bacteria ratios throughout the second seeding period. Our
study shows that dust deposition to the surface oligotrophic ocean may
involve important modifications of the trophic links among the components of
the microbial food web with presumed consequences on C and nutrient cycling. |
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