title: Enhanced salinities, as a proxy of seawater desalination discharges, impact coastal microbial communities of the eastern Mediterranean Sea.
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.
authors.affiliation: Mina and Everard Goodman Faculty of Life Sciences, Bar-Ilan University, Ramat Gan, 52900, Israel.
authors.forename: Natalia
authors.initials: N
authors.lastname: Belkin
authors.affiliation: Israel Oceanographic and Limnological Research, National Institute of Oceanography, Haifa, 31080, Israel.
authors.forename: Eyal
authors.initials: E
authors.lastname: Rahav
authors.affiliation: Mina and Everard Goodman Faculty of Life Sciences, Bar-Ilan University, Ramat Gan, 52900, Israel.
authors.forename: Hila
authors.initials: H
authors.lastname: Elifantz
authors.affiliation: Israel Oceanographic and Limnological Research, National Institute of Oceanography, Haifa, 31080, Israel.
authors.forename: Nurit
authors.initials: N
authors.lastname: Kress
authors.affiliation: Mina and Everard Goodman Faculty of Life Sciences, Bar-Ilan University, Ramat Gan, 52900, Israel.
authors.forename: Ilana
authors.initials: I
authors.lastname: Berman-Frank
mesh_terms: D001419:Bacteria / Q000235:genetics / Q000378:metabolism*; D001483:Base Sequence; D044822:Biodiversity; D002734:Chlorophyll / Q000235:genetics; D000077194:Chlorophyll A; D004269:DNA, Bacterial / Q000235:genetics; D056890:Eukaryota / Q000502:physiology; D020387:Food Chain; D008522:Mediterranean Sea; D059013:Microbial Consortia; D009994:Osmolar Concentration; D010933:Plankton / Q000378:metabolism* / Q000382:microbiology; D054712:Salinity; D012621:Seasons; D012623:Seawater / Q000737:chemistry* / Q000382:microbiology*; D017422:Sequence Analysis, DNA; D012965:Sodium Chloride / Q000378:metabolism*
chemical_list: D004269:DNA, Bacterial; D002734:Chlorophyll; D012965:Sodium Chloride; D000077194:Chlorophyll A