Phylogenetic diversity of soda lake alkaliphiles

16S rRNA genes from a range of aerobic chemoorganotrophic, alkaliphilic soda lake Bacteria and Archaea have been sequenced and subjected to phylogenetic analysis. Gram-negative alkaliphiles were found to be confined to the γ3 subdivision of the Proteobacteria, with many isolates related to the Halomonas/Deleya group. Gram-positive alkaliphiles were found in both high % G + C and low % G + C divisions of the Gram-positive lineage, with many isolates being related to the Bacillus group, others to Arthrobacter spp. Alkaliphilic Archaea were relatively closely related to members of the genera Natronococcus and Natronobacterium. An anaerobic, thermophilic isolate has been assigned to a new genus within the Thermotogales.