Biology ETDs

Publication Date

Summer 7-28-2026

Abstract

Long-term studies are the most effective way to understand an ecosystem. However, time series studies often lack a microbial community component, despite the widely recognized importance of microbial community contribution to nutrient cycling and ecosystem function.  This is in large part due to the rapid development of sequencing technology.  The McMurdo Dry Valleys (MDVs), Antarctica have been studied by the Long-Term Ecological Research project since 1993. The MDVs are landmarked by permanently frozen lakes which are disproportionately driven by microbial species.  The LTER has consequentially invested in increased focus on these communities, resulting in one of the longest, highly comparable, and high-fidelity microbial sequencing records. Through this long-term dataset, I have identified an association between community diversity and both lake ice thickness and photosynthetically active radiation (PAR), in which thinning ice and increased PAR lead to a decrease in richness.  These communities are sensitive to subtle changes in light and show distinct community shifts related to seasonality. Despite isolation from external input, diversity in the system is maintained through negative frequency dependent selection, in which rare species have increased fitness. Overall, communities in the lakes are dynamic and controlled by overlaying ice cover.

Project Sponsors

McMurdo Dry Valleys LTER

Language

English

Keywords

Antarctica, microbiology, ecology, sequencing, limnology

Document Type

Dissertation

Degree Name

Biology

Level of Degree

Doctoral

Department Name

UNM Biology Department

First Committee Member (Chair)

Cristina Takacs-Vesbach

Second Committee Member

Rebecca Bixby

Third Committee Member

Tyler Mackey

Fourth Committee Member

Davorka Gulisija

Fifth Committee Member

Mitchell Newberry

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Available for download on Friday, July 28, 2028

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