Degree of oligotrophy controls the response of microbial plankton to Saharan dust

Emilio Marañón*, Ana Fernández, Beatriz Mouriño-Carballido, Sandra Martínez-García, Eva Teira, Pedro Cermeño, Paloma Chouciño, María Huete-Ortega, Emilio Fernández, Alejandra Calvo-Díaz, Xosé Anxelu G. Morán, Antonio Bode, Enrique Moreno-Ostos, Marta M. Varela, Matthew D. Patey, Eric P. Achterberg

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

111 Scopus citations


To determine the effects of Saharan dust on the abundance, biomass, community structure, and metabolic activity of oceanic microbial plankton, we conducted eight bioassay experiments between ca. 30°N and 30°S in the central Atlantic Ocean. We found that, although bulk abundance and biomass tended to remain unchanged, different groups of phytoplankton and bacterioplankton responded differently to Saharan dust addition. The predominant type of metabolic response depended on the ecosystem's degree of oligotrophy and was modulated by competition for nutrients between phytoplankton and heterotrophic bacteria. The relative increase in bacterial production, which was the dominant response to dust addition in ultraoligotrophic environments, became larger with increasing oligotrophy. In contrast, primary production, which was stimulated only in the least oligotrophic waters, became less responsive to dust as the ecosystem's degree of oligotrophy increased. Given the divergent consequences of a predominantly bacterial vs. phytoplanktonic response, dust inputs can, depending on the ecosystem's degree of oligotrophy, stimulate or weaken biological CO2 drawdown. Thus, the biogeochemical implications of changing dust fluxes might not be universal, but variable through both space and time.

Original languageEnglish (US)
Pages (from-to)2339-2352
Number of pages14
JournalLimnology and Oceanography
Issue number6
StatePublished - Nov 2010
Externally publishedYes

ASJC Scopus subject areas

  • Oceanography
  • Aquatic Science


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