Drop-size soda lakes: Transient microbial habitats on a salt-secreting desert tree

We describe a hitherto unrecognized bacterial community, inhabiting the leaf surfaces of the salt-excreting desert tree Tamarix. High temperatures, strong radiation, and very low humidity dictate a daytime existence in complete desiccation, but clamp nights allow the microbial population to proliferate in a sugar-rich, alkaline, and hypersaline solution, before drying tip again after sunrise. The exclusively bacterial population contains many undescribed species and genera, hilt nevertheless appears to be characterized by relatively limited species diversity. Sequences of 16S rRNA genes from either isolates or total community DNA place the identified members of the community in fee bacterial groups (Actinobacteria, Bacteroidetes, Firmicutes, alpha-, and gamma-Proteobacteria); in each of these, they concentrate in a very narrow branch that in most cases harbors organisms isolated from unrelated halophilic environments.