Award Date

May 2023

Degree Type


Degree Name

Doctor of Philosophy (PhD)


Life Sciences

First Committee Member

Brian Hedlund

Second Committee Member

Jef Jaeger

Third Committee Member

Helen Wing

Fourth Committee Member

Duane Moser

Fifth Committee Member

Laura Rademacher

Sixth Committee Member

Elisabeth Hausrath

Number of Pages



Desert springs are aquatic oases, being considered among the most diverse and imperiled ecosystems on Earth. Despite the ecological significance and threatened status of desert springs, few studies have surveyed the microorganisms in these systems or their interactions with other community members. The primary goal of this dissertation was to describe the major controls influencing the community ecology of prokaryotic and BMI communities in cold- and moderate-temperature desert springs of the southern hydrographic Great Basin. Chapter 1 provides a broad overview of spring ecosystems and of each chapter included in this dissertation. Chapter 2 documents the first-ever, regional-scale survey of the desert spring microbiome and describes the differences in diversity, composition, and functional profiles between the major spring recharge groups. This chapter also contains an extended analysis placing the desert spring microbiome within the context of the Earth Microbiome Project database to assess the uniqueness of desert springs as a biome and identify potential prokaryotic crenophiles and/or endemics. Chapters 3 and 4 discuss geological and ecological controls on the community ecology of benthic prokaryotes and BMIs within a detailed ecohydrogeological framework at a local (Chapter 4) and regional (Chapter 3) scale. These chapters also speculate about possible metabolic interactions occurring between these two communities in the spring benthos food web. Further, Chapter 3 presents a conceptual model of desert spring benthic communities characterizing the dominant physicochemical and biological differences between spring recharge groups. Although a deviation from the primary goal of this dissertation, Chapter 5 describes the first cultivation-independent survey of the Atlantic horseshoe crab (Limulus polyphemus) microbiome in wild and captive populations. Chapter 6 briefly summarizes the major conclusions of each chapter and discusses possible directions for future research on spring ecosystems.


desert springs; Earth Microbiome Project; ecohydrogeology; endemism; synecology


Biology | Environmental Sciences | Microbiology

Degree Grantor

University of Nevada, Las Vegas




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