All ETDs from UAB

Advisory Committee Chair

Robert Thacker

Advisory Committee Members

James Coker

Daniel Warner

Document Type

Thesis

Date of Award

2015

Degree Name by School

Master of Science (MS) College of Arts and Sciences

Abstract

Hypersaline environments (salt concentrations greater than two molar) are found on all continents and represent a woefully understudied ecosystem. To date, most of the hypersaline environments studied have been either lakes (e.g. The Great Salt Lake, Utah) or deep ocean/sea brine pools (e.g. Red Sea), both of which have an abundance of accessible water for the organisms living there. However, more extreme hypersaline environments have not been characterized as thoroughly. One of these environments is the Bonneville Salt Flats (BSF) in Western Utah. The BSF is 80 square miles in size and consists of a salt crust of varying thickness (0.5 inches to 5 feet) situated on top of a shallow brine aquifer. It experiences intense radiation and its only sources of water are meteorological events and upwelling from a shallow brine aquifer. The combination of high salt, water scarcity, and intense radiation provides an interesting mix of selection pressures and were the common reasons given as to why the BSF was thought to have no extant life. My work, presented here, was the first to report that there is extant life in the BSF and helps provide a better understanding of the structure and dynamics of the microbial population contained within this extreme type of saline environment. I began by growing isolates on various types of media containing four molar salt to replicate the environment and maximize the possibility of isolating true microbial inhabitants of the environment. During this process I observed a variety of colony morphologies, cell shapes, pigments, and other external features. I then selected a subset of the organisms and began determining the temperature growth range/kinetics for each organism. The genus/species of each organism was also determined through PCR amplification and sequencing of the 16S rRNA gene. Finally, I performed analyses to link the phylogenetics of each organism to its native niche in the BSF in an attempt to determine how the microenvironments select for different genera. My analysis of the isolates will help elucidate and further characterize the microorganisms thriving in this polyextremophilic ecosystem and the effects of the selection pressures present in this environment.

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