The importance of predators in influencing community structure is a well-studied area of ecology. However, few studies apply ecological hypotheses of predation when studying multi-predator systems, and even fewer apply these theories to microbial communities. The phytotelma community found within the leaves of the purple pitcher plant, Sarrecenia purpurea, exhibits a simple trophic structure that includes the micro-scale interactions of protozoan predators and microbial prey, making this microcosm ideal for studying how predator diversity and composition affects microbial community structure. Replicate inquiline microbial communities were maintained for seven days with five protozoan species (four ciliates and one flagellate) in a factorial design. We sought to determine how predator diversity (up to four species) affects prey community diversity, whether different predators target distinct microorganisms, and how interactions among protozoans affect resource (microorganism) use. In so doing, we sought to determine if predators followed ecological patterns of keystone predation or generalist predation. Microbial community structure was analyzed by 16S rRNA gene sequencing (iTag). The data revealed that Archaea were rare, with Proteobacteria and Bacteriodetes dominating regardless of treatment. Of the different protozoan species, two ciliates and one flagellate distinctly altered their communities as compared to one another (p<0.05). The ciliates followed patterns of keystone predation by increasing microbial evenness, while the flagellate left a community statistically similar to the control and followed generalist patterns. When in pairwise treatments, remaining prey communities more closely resembled those of the respective ciliate than that of the flagellate (as compared to these communities in monoculture). The relative abundance of one bacterial Operational Taxonomic Unit (OTU) classified as an Aquitalea sp. decreased from the control when in the presence these two ciliates. This OTU is 98% similar to an Aquitalea sp. associated with chitin degradation, an important function for this plant's fitness. Associated predicted metabolic functions revealed a positive correlation with the relative abundance of this OTU and chitinase, as well as an inverse correlation with community evenness. Taken together, the data demonstrated that specific predator behaviors may have a greater affect on prey diversity and relative abundances than overall predator diversity. Based on metabolic predictions, these trends could have an affect on microbial community function with consequences that reverberate throughout the trophic structure. / A Thesis submitted to the Department of Earth, Ocean, and Atmospheric Sciences in partial fulfillment of the requirements for the degree of Master of Science. / Spring Semester 2017. / April 14, 2017. / Includes bibliographical references. / Olivia U. Mason, Professor Directing Thesis; Thomas E. Miller, Committee Member; Sven Kranz, Committee Member.
| Identifer | oai:union.ndltd.org:fsu.edu/oai:fsu.digital.flvc.org:fsu_507637 |
| Contributors | Canter, Erin J. (Erin Josephine) (authoraut), Mason, Olivia Underwood (professor directing thesis), Miller, Thomas E. (committee member), Kranz, Sven Alexander (committee member), Florida State University (degree granting institution), College of Arts and Sciences (degree granting college), Department of Earth, Ocean, and Atmospheric Sciences (degree granting departmentdgg) |
| Publisher | Florida State University, Florida State University |
| Source Sets | Florida State University |
| Language | English, English |
| Detected Language | English |
| Type | Text, text, master thesis |
| Format | 1 online resource (32 pages), computer, application/pdf |
| Rights | This Item is protected by copyright and/or related rights. You are free to use this Item in any way that is permitted by the copyright and related rights legislation that applies to your use. For other uses you need to obtain permission from the rights-holder(s). The copyright in theses and dissertations completed at Florida State University is held by the students who author them. |
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