Enhanced salinities, as a proxy of seawater desalination discharges, impact coastal microbial communities of the eastern Mediterranean Sea

Natalia Belkin, Eyal Rahav, Hila Elifantz, Nurit Kress, Ilana Berman-Frank

Research output: Contribution to journalArticlepeer-review

Abstract

Seawater desalination plants increase local coastal salinities by discharging concentrated brine back to the sea with ∼50% higher than ambient salinities. The impacts of high salinities on microbial coastal populations of the eastern Mediterranean Sea (EMS) were examined in two mesocosm experiments; first, during the mixed-spring and second, during the stratified-summer periods with average salinity of ∼39. Ambient salinities were increased by 5% and 15%. Higher salinity (15%) mesocosms induced rapid (within 2 h) declines in both primary productivity (PP) and algal biomass parallel to an increase in bacterial productivity. Subsequently, for the duration of the experiments (11–12 days), both Chlorophyll a and PP rates increased (2 to 5 and 1.5 to 2.5–fold, respectively) relative to unamended controls. The initial assemblages of the ambient microbial populations and intensity of salinity enrichments influenced the community responses. During the mixed-spring experiment, the composition of prokaryotic and eukaryotic populations shifted only slightly, suggesting high functional plasticity of the initial populations. While during the stratified-summer experiment, high salinity changed the composition and reduced the biodiversity of the microbial communities. In an ultra-oligotrophic environment such as the EMS, salinity induced declines in microbial diversity may provide a tipping point destabilizing the local aquatic food web.

Original languageEnglish
Pages (from-to)4105-4120
Number of pages16
JournalEnvironmental Microbiology
Volume17
Issue number10
DOIs
StatePublished - 1 Oct 2015
Externally publishedYes

Bibliographical note

Publisher Copyright:
© 2015 Society for Applied Microbiology and John Wiley & Sons Ltd

ASJC Scopus subject areas

  • Ecology, Evolution, Behavior and Systematics
  • Microbiology

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