Graduation Date

Fall 2023

Document Type



Master of Science degree with a major in Biology

Committee Chair Name

Catalina Cuellar-Gempeler

Committee Chair Affiliation

HSU Faculty or Staff

Second Committee Member Name

Paul Bourdeau

Second Committee Member Affiliation

HSU Faculty or Staff

Third Committee Member Name

Karen Kiemnec-Tyburczy

Third Committee Member Affiliation

HSU Faculty or Staff

Fourth Committee Member Name

Jianmin Zhong

Fourth Committee Member Affiliation

HSU Faculty or Staff

Subject Categories



In the context of multispecies microbial assemblages, disruptions can occur when there are alterations in host conditions, such as the onset of a disease. Notably, viruses have the potential to reshape a host's microbial community. However, the role of the host's habitat and environment, which could be pivotal in communities with shifting niche space and habitat filters, is often overlooked in host-microbe-pathogen interactions. Recognizing the importance of these factors, I employed a field-based approach to understand microbial community dynamics in the presence of disease. To address the influence of geographical location, I conducted an analysis involving healthy and infected oysters at two distinct sites (Tomales Bay, CA and Humboldt Bay, CA) using hypotheses based upon previous laboratory research on Ostreid herpesvirus (OsHV-1) effects on oyster microbial community. Using 16S rRNA sequencing data and qPCR data, I shed light on the significant impacts of host location and habitat in disease systems, emphasizing their importance in disease research. I found that, 1) microbial community dynamics were impacted by OsHV-1 and geographical location of sample collection. However, the presence of OsHV-1 did not result in decreased richness, diversity, or evenness in the microbial community, contrary to previous research. 2) OsHV-1 infection did not inhibit the oyster microbial community’s ability to filter its environment. 3) Contrary to expectations, Vibrio abundance did not exhibit a significant increase with OsHV-1 load. 4) The microbial community in infected samples did not exhibit dominance by Vibrio, again, contrary to previous laboratory-based results. These findings shed light on the significant impacts of host location and habitat in disease systems, emphasizing their importance and underscoring the critical need to integrate community ecology studies into disease research. By understanding how host location, habitat, and the broader environment shape microbial communities, we can gain valuable insights into disease dynamics, ultimately advancing our ability to manage and mitigate disease impacts effectively.

Citation Style



Thesis/Project Location


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