Year of Award

2011

Document Type

Thesis

Degree Type

Master of Science (MS)

Other Degree Name/Area of Focus

Microbiology

Department or School/College

Division of Biological Sciences

Committee Chair

Scott R. Miller

Commitee Members

Jim Gannon, Winsor Lowe

Keywords

Chloroflexus, community assembly, hot springs microbiology

Publisher

University of Montana

Abstract

This research aims to achieve a greater understanding of the structure of bacterial communities present in alkaline hot springs in Yellowstone National Park. I focus specifically on White Creek and Rabbit Creek in the Lower Geyser Basin. I show that, overall, the bacterial communities of both creeks are non-randomly assembled. However, at finer taxonomic scales, bacterial groups differ in their community assembly patterns. Specifically, phototrophic groups show the strongest evidence for non-random assembly, most likely due to competition for light. A major exception to this pattern is the genus Chloroflexus, a major member of these communities. Members of this genus primarily grow phototrophically, yet they did not show evidence of non-random assembly, as only one major 16S ribosomal RNA (rRNA) sequence was detected. Therefore, I next explored whether this single 16S rRNA sequence represents a single, broadly-distributed generalist or several cryptic specialist lineages. I isolated eleven strains of Chloroflexus from White Creek and determined that these isolates are members of a group without previously cultured representatives. I show that strains isolated from different temperatures have recently diverged within White Creek, as they can be differentiated genetically by the propionyl Co-A synthase gene, as well as phenotypically by differences in thermotolerance.

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© Copyright 2011 Michael Louis Weltzer