Biodiversity in Highly Saline Environments

This chapter explores the world of high salt environments worldwide and the diversity of microorganisms that inhabit these environments. Highly saline environments can be encountered on all continents. Coastal solar salterns, found worldwide in dry tropical and subtropical climates, are man-made, thalassohaline hypersaline environments in which sea-water is evaporated for the production of salt. It is therefore not surprising that these saltern ecosystems have become popular objects for the study of microbial biodiversity and community dynamics at high salt concentrations, and much of one's understanding of the biology of halophilic microorganisms is based on studies of the saltern environment and in-depth studies of microorganisms isolated from such salterns. When soon afterward the organism, a rod-shaped red aerobic bacterium, was brought into culture, the organism appeared to be extremely interesting, and its study has deepened the understanding of phylogenetic as well as physiological and metabolic diversity in the world of halophiles. More extensive molecular ecological studies have been made in the Alicante salterns along the salt gradient, to obtain a more complete picture of the development of the microbial diversity as the salinity increases during the gradual evaporation of seawater.