Award Date
5-15-2026
Degree Type
Dissertation
Degree Name
Doctor of Philosophy (PhD)
Department
Life Sciences
First Committee Member
Brian Hedlund
Second Committee Member
Duane Moser
Third Committee Member
Nicole Pietrasiak
Fourth Committee Member
Diana Northup
Fifth Committee Member
Elisabeth Hausrath
Number of Pages
225
Abstract
In this dissertation, our main goal was to characterize life associated with air- and water-filled voids in the subsurface. This included a broad range of environments, including lava caves and two different access points into the Death Valley Regional Flow System (DVRFS). Chapter 1 provides an introduction to the deep subsurface biome and core concepts. In Chapter 2, the relation between lava cave features and microbial and eukaryotic organisms found in Lava Bed National Monument, CA, was explored. This is the most comprehensive study to date on life in/on mineral and ooze features in lava caves. Chapters 3 and 4 focused on microbial communities in different environments associated with the DVRFS. In Chapter 3, we tracked variation in chemistry, physicochemical parameters, and microbial composition during a detailed sampling of BLM-1, a 750 m well in the discharge region of the DVRFS, with the goal of identifying the volume of purging needed for an uncontaminated formation water sample to be collected. This chapter identified potential well artifacts and challenges associated with the collection of high-quality deep subsurface samples. In Chapter 4, we studied the microbiome associated with the endangered Devils Hole Pupfish (Cyprinodon diabolis). These fish are endemic to Devils Hole, a skylight cave atop a limnocrene spring that accesses water from the DVRFS. We compared the pupfish microbiomes of captive fish residing at the Ash Meadows Fish Conservation Facility (AMFCF), a facility that aims to maintain a backup population of Devils Hole pupfish for repopulation of Devils Hole in the event the native population hits a critical low. Chapter 5 summarizes the conclusions of each chapter, presents ideas for further work in these subsurface environments, and discusses unifying themes.
Controlled Subject
Microorganisms; Ecology; Microbiomes
Disciplines
Biology | Life Sciences | Microbiology
File Format
File Size
5000 KB
Degree Grantor
University of Nevada, Las Vegas
Language
English
DevlinM_Supplemental_Data_3-1.xlsx (17 kB)
DevlinM_Supplemental_Data_3-2.xlsx (53 kB)
Repository Citation
Devlin, Molly G., "Culture-Independent Investigations of Microbial Communities Associated With Air- and Water-Filled Voids in the Subsurface" (2026). UNLV Theses, Dissertations, Professional Papers, and Capstones. 5529.
https://oasis.library.unlv.edu/thesesdissertations/5529
Rights
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