Date of Award
1-1-2024
Document Type
Dissertation
Degree Name
Ph.D. in Biological Science
First Advisor
Colin R. Jackson
Second Advisor
Susan Adams
Third Advisor
James Cizdziel
Relational Format
dissertation/thesis
Abstract
Nutrient cycling in freshwater systems is primarily performed by microorganisms, however the interactions between microorganisms and other aquatic organisms such as macroinvertebrates is poorly understood. Interactions between macroinvertebrates and their associated microbial community, their microbiome, are important to understanding ecosystem functioning and guiding conservation efforts for imperiled macroinvertebrate species. In this study, I characterized the microbiomes of various freshwater macroinvertebrates and investigated the influence of sample storage methods and environmental parameters on these microbial communities. I first evaluated the impact of different sample preservation methods on the gut microbiome of two crayfish species, Procambarus vioscai paynei collected in the field and Faxonius virilis maintained in an aquarium, and three species of field-collected dragonfly nymphs. From this, I determined that 95% ethanol is an appropriate storage method to maintain the integrity of the external and gut microbiomes of aquatic invertebrates. In a second study, I investigated the validity of microbiome samples from freshwater mussel species after long-term preservation in ethanol. I determined that ethanol preservation ranging between 2-9 years did not significantly hinder sequencing depth or bacterial species richness of their gut microbiomes, and provided additional insight into the core gut microbiota of freshwater bivalve species. Focusing more on the effects of freshwater invertebrates and their microbiome on biogeochemical processes, a third study examined the influence of bivalves and crayfish on processes, a third study examined the influence of bivalves and crayfish on water column enzyme activity and bacterial community structure, and revealed distinct responses of the aquatic bacterial community to the presence of these macroinvertebrates, likely driven by differences in behavior and mobility. Finally, I investigated the effects of the environment and host development on the gut microbiome of two species of hatchery-raised mussels (Lampsilis ovata and Lampsilis ornata) transplanted into natural rivers. This study demonstrated that the gut microbiome structure in these mussels varied by site and, after transplants, shifted to resemble the gut microbiome of mussels in their new environment. Collectively, these studies enhance our understanding of the complex interactions between macroinvertebrates and microbial communities in freshwater ecosystems and underscore the importance of considering host-microbiome-environment interactions in conservation and management strategies.
Recommended Citation
Vaughn, Stephanie Nicole, "The Microbial Communities of Freshwater Invertebrates and Their Influence on Biogeochemical Cycling" (2024). Electronic Theses and Dissertations. 2891.
https://egrove.olemiss.edu/etd/2891