Microbial food web dynamics in response to a Saharan dust event: Results from a mesocosm study in the oligotrophic Mediterranean Sea

E. Pulido-Villena, A. C. Baudoux, I. Obernosterer, M. Landa, J. Caparros, P. Catala, C. Georges, J. Harmand, Cecile Guieu

Research output: Contribution to journalArticle

Abstract

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.

Original languageEnglish (US)
Pages (from-to)5607-5619
Number of pages13
JournalBiogeosciences
Volume11
Issue number19
DOIs
StatePublished - Oct 14 2014

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mesocosm
Mediterranean Sea
dust
food webs
food web
seeding
sowing
virus
viruses
respiration
oceans
microbial loop
bacterium
bacteria
ocean
nutrient cycling
bacterial communities
biogeochemical cycles
community composition

ASJC Scopus subject areas

  • Ecology, Evolution, Behavior and Systematics
  • Earth-Surface Processes

Cite this

Microbial food web dynamics in response to a Saharan dust event : Results from a mesocosm study in the oligotrophic Mediterranean Sea. / Pulido-Villena, E.; Baudoux, A. C.; Obernosterer, I.; Landa, M.; Caparros, J.; Catala, P.; Georges, C.; Harmand, J.; Guieu, Cecile.

In: Biogeosciences, Vol. 11, No. 19, 14.10.2014, p. 5607-5619.

Research output: Contribution to journalArticle

Pulido-Villena, E, Baudoux, AC, Obernosterer, I, Landa, M, Caparros, J, Catala, P, Georges, C, Harmand, J & Guieu, C 2014, 'Microbial food web dynamics in response to a Saharan dust event: Results from a mesocosm study in the oligotrophic Mediterranean Sea', Biogeosciences, vol. 11, no. 19, pp. 5607-5619. https://doi.org/10.5194/bg-11-5607-2014
Pulido-Villena, E. ; Baudoux, A. C. ; Obernosterer, I. ; Landa, M. ; Caparros, J. ; Catala, P. ; Georges, C. ; Harmand, J. ; Guieu, Cecile. / Microbial food web dynamics in response to a Saharan dust event : Results from a mesocosm study in the oligotrophic Mediterranean Sea. In: Biogeosciences. 2014 ; Vol. 11, No. 19. pp. 5607-5619.
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