Extremely halophilic Bacteria in crystallizer ponds from solar salterns

It is generally assumed that hypersaline environments with sodium chloride concentrations close to saturation are dominated by halophilic members of t he domain Archaea, while Bacteria are not considered to be relevant in this kind of environment. Here, we report the high abundance and growth of a ne w group of hitherto-uncultured Bacteria in crystallizer ponds (salinity, fr om 30 to 37%) from multipond solar salterns. In the present study, these Ba cteria constituted from 5 to 25% of the total prokaryotic community and wer e affiliated with the Cytophaga-Flavobacterium-Bacteroides phylum. Growth w as demonstrated in saturated NaCl. A provisional classification of this new bacterial group as "Candidatus Salinibacter gen. nov." is proposed. The pe rception that Archaea are the only ecologically relevant prokaryotes in hyp ersaline aquatic environments should be revised.