title: Archaeal diversity along a soil salinity gradient prone to disturbance.
abstract: We employed a cultivation-independent approach to examine archaeal diversity along a transient soil salinity gradient at Salt Spring in British Columbia, Canada that is routinely eroded due to heavy, recurrent rainfall. Archaeal 16S rRNA gene libraries were created using DNA extracted from three soil samples collected along this gradient. Statistical comparisons indicated similar archaeal richness across sites but, a significant shift in archaeal community composition along the salinity gradient. Seven distinct phylogenetic groups were represented in soil libraries. Haloarchaea were the most commonly sampled group. Other 16S rRNA sequences were related to uncultured Euryarchaeota and Crenarchaeota or halophilic methanogens. Haloarchaeal diversity was remarkably high in soil of elevated salinity compared with previously characterized haloarchaeal communities. Salt Spring haloarchaea were not closely related to known low-salt adapted/tolerant species, suggesting they may be frequently faced with local mortality as a result of frequent declines in soil salinity. We speculate that ecosystem disturbance -- in the form of salinity fluctuations -- is one mechanism for maintaining a diverse community of haloarchaea at Salt Spring.
authors.affiliation: Canadian Institute for Advanced Research Program in Evolutionary Biology and Genome Atlantic, Department of Biochemistry and Molecular Biology, Dalhousie University, 5850 College Street, Halifax, Nova Scotia B3H1X5, Canada. dawalsh@dal.ca
authors.forename: David A
authors.initials: DA
authors.lastname: Walsh
authors.forename: R Thane
authors.initials: RT
authors.lastname: Papke
authors.forename: W Ford
authors.initials: WF
authors.lastname: Doolittle
mesh_terms: D019615:Crenarchaeota / Q000145:classification* / Q000235:genetics / Q000302:isolation & purification; D019641:DNA, Archaeal / Q000032:analysis / Q000302:isolation & purification; D004275:DNA, Ribosomal / Q000032:analysis; D017753:Ecosystem; D019605:Euryarchaeota / Q000145:classification* / Q000235:genetics / Q000302:isolation & purification; D015723:Gene Library; D020459:Genes, rRNA; D014644:Genetic Variation; D008969:Molecular Sequence Data; D010802:Phylogeny; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D011891:Rain; D017422:Sequence Analysis, DNA; D012965:Sodium Chloride; D012987:Soil / Q000032:analysis; D012988:Soil Microbiology
chemical_list: D019641:DNA, Archaeal; D004275:DNA, Ribosomal; D012336:RNA, Ribosomal, 16S; D012987:Soil; D012965:Sodium Chloride