N-180. Microbial Diversity and Functional Ecology of the Great Salt Lake
The Great Salt Lake (GLS) in Utah is the second most saline lake and the fourth largest terminal lake in the world. Because of its high salinity, the GSL represents a unique environment, and has limited biological diversity in the main (hypersaline) portions of the lake. The study of the lake environment is complicated by the arid climate in the region and the variable yearly precipitation that has an impact on the lake size and salinity. In recent years increased interest in microorganisms from hypersaline environments has led to the discovery in the GSL of new bacterial and archaeal genera. Despite those findings the microbial ecology of the GSL remains poorly understood due to cultivability limitations. To determine the structure and ecosystem function of microbial communities in hypersaline environments we have started an extensive analysis of the phylogenetic and physiological diversity of the halophilic microbial communities existing in the GSL. The microbial diversity in the GSL was assessed using a 16S Phylogenetic Array (Phylochip) containing probes for 8,741 bacterial and archaeal taxa. The physiological diversity in the GSL was measured using a comprehensive functional gene array (GeoChip) containing over 24,000 probes for genes involved in various biogeochemical, ecological and environmental processes. We used compounds and metabolites detected by mass spectroscopy of GSL water to complement the functional genes detected with the GeoChip and determine the metabolic pathways that are functioning in the GSL. The Phylochip indicated 150 to 450 different bacterial genera dominated by gamma and alphaproteobacteria. The greatest difference in diversity occurred between the hypersaline North Arm and moderately saline South Arm and Farmington Bay. The GeoChip results showed the presence of 4,560 different genes, favoring biodegradation genes. This result was partially confirmed by metabolite analysis. To our knowledge this is the first attempt to assemble a global phylogenetic and functional biodiversity within the GSL. Our data reveals a predominance of genes involved in sulfur cycling and heavy metal toxicity within the GSL.