The vast majority of theses in this collection are open access and freely available. There are a small number of theses that have access restricted to the WWU campus. For off-campus access to a thesis labeled "Campus Only Access," please log in here with your WWU universal ID, or talk to your librarian about requesting the restricted thesis through interlibrary loan.

Date Permissions Signed


Date of Award

Summer 2019

Document Type

Masters Thesis

Department or Program Affiliation

Biology Department

Degree Name

Master of Science (MS)



First Advisor

Moyer, Craig L.

Second Advisor

Fullerton, Heather

Third Advisor

Zinkgraf, Matthew

Fourth Advisor

Young, Jeff C. (Jeffery C.)


The primary production by Zetaproteobacteria at iron-rich vents of the Mariana Arc and back-arc supports high microbial diversity. In microaerophilic circumneutral pH, Zetaproteobacteria are able to produce energy by oxidizing ferrous iron (Fe2+) from the vent effluent with the presence of a key gene involved in their iron-oxidation, Cyc2, a fused cytochrome-porin. These genes are found in all Zetaproteobacteria known to date. This study combines molecular quantitative techniques with metagenomic analyses to enhance our confidence in gene quantification from environmental samples. The occurrence of cyc2 was quantified from microbial mat communities at NW Eifuku, NW Rota-1, Snail and Urashima Vents using primers designed from a composite metagenome to better understand the potential impact of Zetaproteobacteria metabolism on these iron-rich microbial communities. Based on a multiple sequence alignment and phylogenetic analysis, two distinct groups of the Zetaproteobacteria cyc2 were identified and termed Cluster 1 cyc2 and Cluster 3 cyc2 based on the nomenclature provided by Chan et al. (2018). Multidimensional scaling of Zetaproteobacteria SSU rRNA and cyc2 gene abundances showed that the presence of the two cyc2 sequence variants are strongly driven by an array of different vent fluid chemicals. We also report on the phylogenetic relationship between the two cyc2 variants and other representative FeOB, as well as the distribution of cyc2 gene abundances across the Mariana hydrothermal vent sites along the Arc and back-arc. Overall, this provides insight on the ecological and evolutionary implications of Zetaproteobacteria iron-oxidation represented at the community-level across a wide-range of geochemical parameters.




Functional genes, Microbial communities, Quantitative polymerase chain reaction


Western Washington University

OCLC Number


Subject – LCSH

Proteobacteria--Philippine Sea--Genetics; Metagenomics--Philippine Sea; Hydrothermal vents--Microbiology--Philippine Sea

Geographic Coverage

Philippine Sea




masters theses




Copying of this document in whole or in part is allowable only for scholarly purposes. It is understood, however, that any copying or publication of this document for commercial purposes, or for financial gain, shall not be allowed without the author’s written permission.

Included in

Biology Commons