Chairperson, Graduate Committee: Mark J. YoungSnyder, Jamie Christine2013-06-252013-06-252005https://scholarworks.montana.edu/handle/1/2317Few viruses from Archaea have been described and only a limited number have been characterized in molecular detail. Most hyperthermophilic viruses isolated from the archaeal sub-domain Crenarchaeota belong to the Sulfolobales family. We have focused on the isolation and analysis of viruses replicating in Sulfolobus. Sulfolobus is an acidophilic hyperthermophile that lives optimally at 80°C and pH 3. The SSVs (Sulfolobus spindle-shaped viruses) are the viruses most commonly isolated from thermal acidic areas around the world. SSVs are dsDNA spindle-shaped viruses with genomes of approximately 15kb. They are also the predominant virus isolated from samples collected in Yellowstone National Park (YNP). The SIRVs (Sulfolobus islandicus rodshaped viruses) are also commonly isolated from YNP. These viruses have linear dsDNA genomes of approximately 33kb. I have used these two viruses to investigate the interaction of time and viral population dynamics. For a comparison between geographically isolated acidic hot springs, we chose to study three sites in YNP.These three sites were monitored continuously for changes in virus populations, archaeal host populations, and water chemistry. Each monitor site was chemically unique, but the water chemistry did not significantly change over time. The archaeal population in each of the three hot springs was unique and was found to slowly change over time. We have discovered that although there can be a substantial change in viral population structures in between the collection of samples, it does not seem to be correlated with a changing environmental parameter. There also appears to be a strong culturing bias present in the SSVs when we compare the virus population monitored directly from the environment to the viruses isolated from an enrichment culture established from a particular hot spring. A long term goal is to contribute to the understanding of the relationships between time and resident viral populations within hot spring environments. We hope this work will contribute a further understanding of life in extreme environments.enMicrobial ecologyHot spring ecologyWaterMicrobiologyArchaebacteriaDissertationCopyright 2005 by Jamie Christine Snyder