Electronic Theses and Dissertations



Document Type


Degree Name

Doctor of Philosophy



Committee Chair

Shawn Brown

Committee Member

Jennifer Mandel

Committee Member

Emily Puckett

Committee Member

Bernie Diagle

Committee Member

Keith Bowers


Snow algae blooms and associated microbial communities play large roles in snow ecosystem processes. Patterns and mechanisms underpinning snow algae bloom spatial distribution and associated microbial community assembly dynamics are poorly understood. To bridge these gaps in knowledge, this dissertation focused on two broad areas: (1) mapping associations of microbial communities and environmental measures between/within snow algae blooms across diverse substrate categories and identifying significant associations between them; (2) metagenome sequencing, offering the first partial genome of Sanguina nivaloides, along with identification of putative functional pathways. Although snow algae are an enigmatic domain in microbial community research, due to the difficulty in culturing these microbes, the findings from this body of research shed new light on the ecological structure of these communities. Through metagenomic methods, field sampling, and novel experimental designs, this research worked to develop an integrated approach to understanding microbial dynamics in the face of diminishing habitat worldwide for cryophilic microbiota due to anthropogenic climate change. Findings from Chapter 1 include: Snows from the Cascade Mountains and the Rocky Mountains (USA) were collected from medial (M), peripheral (P), and adjacent (A) zones of red snow algae blooms. Medial snow shows increased levels of pollen, lower oxidation–reduction potential, decreased algal and increased bacterial richness, and increased levels of potassium when compared to A and P within the same bloom. Between the Cascade and Rocky Mountains, fungal communities are distinct but bacterial and algal communities show little differentiation. A weighted OTU co-expression analysis (WOCNA) explores OTU modules and their differential correlation with environmental features, suggesting certain subcommunities may be altered by ecological patterns. Findings from Chapter 2 include: developed an analytical framework to investigate uncultured taxa using a novel metagenomic Pool-Seq approach, which was used to generate draft genomes of S. nivaloides; provided; identified several putative functional pathways (folate, methane, retinol, and vitamin B6) that were not previously known; and demonstrated distinct population patterns between sampling locations by mapping ORFs. Findings from Chapter 3 include: examines the associations between microbial communities across snow-soil interfaces at the Glacier Lakes Ecosystems Experiment Site (GLEES), finding that S. nivaloides has limited signal in the soils adjacent to snowpack and that the subsurface and surface snows appear house distinct microbial communities.


Data is provided by the student

Library Comment

Dissertation or thesis originally submitted to ProQuest.


Open Access