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TitleAnalysis of microbial communities in natural halite springs reveals a domain-dependent relationship of species diversity to osmotic stress
AuthorRuhl, I A; Grasby, S E; Haupt, E S; Dunfield, P F
SourceEnvironmental Microbiology Reports vol. 10, no. 6, 2018 p. 695-703,
Alt SeriesNatural Resources Canada, Contribution Series 20180256
Mediaon-line; digital
File formatpdf (Adobe® Reader®); docx (Microsoft® Word®)
Subjectsenvironmental geology; Nature and Environment; microorganisms; biological communities; mineral springs; salt springs; halite; osmosis; pH patterns; temperature; salinity; environmental analysis; statistical analyses; Bacteria; Eukarya; Archaea; Halobacteriaceae; microbiology; biological diversity; habitats; osmotic stress; genetics; plants; animals
Illustrationsplots; Venn diagrams
ProgramGeoscience for New Energy Supply (GNES), Geothermal Energy
Released2018 09 24
AbstractMicrobial species diversity may peak at certain optimal environmental conditions and decrease toward more extreme conditions. Indeed, bell-shaped relationships of species diversity against pH and temperature have been demonstrated, but diversity patterns across other environmental conditions are less well reported. In this study, we investigated the impact of salinity on the diversity of microorganisms from all three domains in a large set of natural springs with salinities ranging from freshwater to halite saturated. Habitat salinity was found to be linearly and inversely related to diversity of all three domains. The relationship was strongest in the bacteria, where salinity explained up to 44% of the variation in different diversity metrics (OTUs, Shannon index, and Phylogenetic Diversity). However, the relationship was weaker for Eukarya and Archaea. The known salt-in strategist Archaea of the Halobacteriaceae even showed the opposite trend, with increasing diversity at higher salinity. We propose that high energetic requirements constrain species diversity at high salinity but that the diversity of taxa with energetically less expensive osmotolerance strategies is less affected. Declining diversity with increasing osmotic stress may be a general rule for microbes as well as plants and animals, but the strength of this relationship varies greatly across microbial taxa.
Summary(Plain Language Summary, not published)
Microbes have significant impact on natural systems, including the generation and degradation of methane. While long suspected, this work provides the first direct evidence that salinity of water controls the microbial diversity of life in that water. A large sample set was collected from springs in northern Canada with salinity from fresh to salt saturated waters and show declining microbial diversity with increasing salinity, largely due to the greater energy required keep salt outside the cell walls. This work provides fundamental insight into controls on microbial life and helps our predicative ability on how microbial ecosystems may affect natural environments.