MICROBIAL DIVERSITY IN HYPERSALINE SEDIMENTS OF THE GREAT SALT LAKE DESERT

The Great Salt Lake Desert (GSLD) is an extensive evaporite basin west of the Great Salt Lake, Utah. Though it looks like a singular basin, it encompasses multiple enclosed sub-basins full of hyper-saline lacustrine sediments; the largest three are the Bonneville Salt Flats, the Pilot Valley basin, and the Newfoundland basin. The Bonneville Salt Flats and the Newfoundland basin are subject to significant anthropogenic alteration due to the local salt mining industry. The sediments of the Pilot Valley basin, however, have remained relatively untouched and uncharacterized. The upper six meters of sediment in this basin constitute a shallow brine aquifer that is maintained through groundwater recharge from precipitation runoff in the nearby Silver Island Mountain Range. XRD and automated electron microscopy (QEMSCAN) show that the surface sediments are a mix of phyllosilicates, carbonates and gypsum. Though the average precipitation in the GSLD is 13 cm/year, the center of the basin can remain saturated with brine fluids throughout the year. In addition to the tendency for hypersaline environments to yield novel diversity and microorganisms, the nature of the hydrological system at Pilot Valley combined with the intermixed clays, carbonates and salt make-up of the sediments makes this ancient lake basin a compelling Mars analog environment for astrobiological investigations, especially in relation to the current Mars Science Laboratory mission at Gale Crater. Here we present results from an ongoing investigation of the microbial diversity of the previously uncharacterized Pilot Valley System.