Master of Science, The Ohio State University, 2008, Graduate School

Committee: Not Provided (Other) Subjects:

Doctor of Philosophy, The Ohio State University, 2019, Microbiology

The Arctic system has been undergoing a rampant change during the Anthropocene. This anthropogenic change has allowed for additional physical and biological positive feedback processes that in turn accelerate warming in the arctic and subarctic systems. Microbial community/functional dynamics are both (i) dramatically impacted by these rapid changes and (ii) key players in the biological positive feedback process that accelerates the change. Recent technological, analytical, and computational advances have allowed us to ask systems-level questions that encompass microbial and viral community dynamics (along with their potential functional dynamics) and high-resolution environmental measurements. This research took a systems-level approach to look for the first time at (i) the characteristics of Arctic marine viruses in a global context, and (ii) microbial community gene expression in a rapidly changing permafrost thaw gradient. Additionally, novel viral sequences recovered from the marine and terrestrial ecosystems studied here were used to build new resources and tools that accelerate viral discovery in nature. First, studying marine viral macro- and microdiversity from the Arctic Ocean to the Southern Ocean, enabled by the Tara Oceans Expedition, revealed the Arctic Ocean as a hotspot of viral diversity, with ~42% of the recovered viral populations originating from the Arctic Ocean viromes. In total 195,728 viral populations >10 kb were recovered from the global ocean to constitute the Global Ocean Viromes 2.0 (GOV2.0) dataset. Viral communities assorted into five distinct global ecological zones and the arctic viral communities formed their own distinct ecological zone. Additionally, this work revealed unexpected patterns and ecological drivers of viral diversity (at the community, inter-, and intrapopulation levels), within the Arctic Ocean, across latitudes, and across the depth of the global ocean. Second, genome-resolved metaproteomic study of microbial gene (open full item for complete abstract)

Committee: Matthew Sullivan (Advisor); Virginia Rich (Advisor); Kelly Wrighton (Committee Member); Alvaro Montenegro (Committee Member) Subjects: Biogeochemistry; Bioinformatics; Biological Oceanography; Biology; Climate Change; Ecology; Environmental Science; Geobiology; Microbiology; Oceanography; Soil Sciences; Statistics; Virology

Doctor of Philosophy (PhD), Ohio University, 2018, Biological Sciences (Arts and Sciences)

My study presents information on summer use of terrestrial habitat by IUCN “endangered” North American Wood Turtles (Glyptemys insculpta), sampled over four years at two forested montane sites on the southern periphery of the species' range in the central Appalachians of Virginia (VA) and West Virginia (WV) USA. The two sites differ in topography, stream size, elevation, and forest composition and structure. I obtained location points for individual turtles during the summer, the period of their most extensive terrestrial roaming. Structural, compositional, and topographical habitat features were measured, counted, or characterized on the ground (e.g., number of canopy trees and identification of herbaceous taxa present) at Wood Turtle locations as well as at paired random points located 23-300m away from each particular turtle location. First, I report and discuss basic morphometric and activity area data of the VA and WV turtles. Chapter two uses a nine-year dataset of adult WV Wood Turtles to estimate population size, population growth rate (lambda), and survivorship with open population Cormack-Jolly-Seber and Pradel models in program MARK. My third chapter assess Wood Turtle thermal ecology by examining three data sets of environmental and turtle temperatures: 1) temperatures in three different microhabitat types (unshaded by ground cover [exposed], under vegetation [UV], under litter [UL]) recorded by iButtons at arrays throughout the two study sites; 2) ground temperatures at the locations of radio-tracked individuals and their paired random points measured within 300 meters and 30 minutes of each other; 3) body temperatures estimated with iButtons attached to the shell bridges of adult Wood Turtles. In the fourth chapter, I examine highly localized conditions resulting from short-term weather patterns and fine-scale microhabitat characteristics by comparing ground-level relative humidity at the locations of radio-tracked Wood Turtles to those at paired ra (open full item for complete abstract)

Committee: Willem Roosenburg Professor (Advisor) Subjects: Animals; Ecology; Environmental Science; Forestry; Wildlife Conservation; Wildlife Management; Zoology

Master of Science (MS), Bowling Green State University, 2017, Biological Sciences

This study took place within the Oak Openings Region, a biodiversity hotspot in northwestern Ohio. The Oak Openings was created during the Cenozoic period, a time where glaciers continuously moved across Ohio, creating valleys and riverbeds. When the Wisconsin glaciers melted back from Ohio around 14,000 years ago, waters were released into multiple lakes with sandy beaches. Overtime, these sandy beaches started to became dunes inundated by rainwater that could not drain past the clayey till and bedrock ground layer. Water that would stand between the clay layer and sandy dunes provided moisture to eventually support oak savanna habitat. Between the sand ridges, rainwater would saturate the land, which created open areas of wet prairie (Higgins, 2003; Grigore, 2004). The combination of oak savanna habitat and open wet prairie gave this region the name of “Oak Openings” (Grigore, 2004). Today, the Oak Openings looks quite different as a result of the economic development and agricultural pursuits along the Toledo-Detroit corridor. This area is highly fragmented by roads, agricultural fields and urban/residential development. Roughly 45% of the Oak Openings Region contains urban and suburban development and roughly a quarter of the region has been converted to areas of agricultural production (Schetter and Root, 2011). However, there are still remnants of wild lands that exist west and south of the city of Toledo. This area is Ohio's largest single surficial sand covering which is 1-12 meters thick and consists of wet lowland and sand ridge terrain with elevations up to 210 meters above sea level. This region is approximately 8 kilometers wide and 32 kilometers long (Higgins, 2003; Figure 1) and contains oak savanna, oak woodland and wet prairie habitats on post glacial beach ridges and swales and covers 478 km2 (The Nature Conservancy, 2001; Grigore, 2004; Schetter and Root, 2011). The Oak Openings Region contains one third of all of Ohio's endangered plant commu (open full item for complete abstract)

Committee: Karen Root (Advisor); Raymond Larsen (Committee Member); Andrew Gregory (Committee Member) Subjects: Animal Sciences; Animals; Biology; Conservation; Ecology; Environmental Studies; Statistics; Wildlife Conservation; Wildlife Management; Zoology

Master of Sciences, Case Western Reserve University, 2017, Biology

This thesis addresses the threats to two closely related species of sea lion, the Galapagos sea lion (Zalophus wollebaeki) and the California sea lion (Zalophus californianus) using mathematical modeling and statistical methods. We address the potential for a novel disease outbreak in the endangered Galapagos sea lion using a simulation model, which predicts the combined effect of El Nino and disease and how this influences the efficacy of options for management practices. We then characterize how El Nino influences life history traits, including birthweight and survival, in the California sea lion, and examine the characteristics that shape dispersal. We test these effects using statistical methods and identify how and at which life stages sea lions are susceptible to stressors. The broader implications for this work are to make recommendations for management and highlight the importance of understanding the threats facing these species.

Committee: Karen Abbott (Advisor); Robin Snyder (Committee Member); Sarah Diamond (Committee Member) Subjects: Ecology

Master of Science (MS), Wright State University, 2016, Biological Sciences

Sex chromosomes are thought to be an important component of the genome associated with speciation and the buildup of reproductive isolation. Recent advances in sequencing technologies and improvements in population genetics and modeling techniques have made it possible to better assess genomic signatures of selection, genetic drift and gene flow in diverging lineages. Recent studies have shown elevated differentiation on the Z sex-chromosome between the Australian grey teal (Anas gracilis) and chestnut teal (Anas castanea). Here, we used next generation sequencing to scan ~3,400 autosomal loci and ~190 Z loci to examine genomic differentiation and signatures of selection and gene flow between grey and chestnut teals. We also inferred demographic history to assess gene flow and signatures of selection. We found weak differentiation in autosomal loci (mean FST = 0.008), but ~ 28-times higher differentiation on the Z-chromosome (mean FST =0.23). We also found that this higher differentiation was localized on the q-arm of the Z chromosome between 15-million and 40-million base pairs. Whereas we could not reject a strict isolation model on the Z chromosome, models that incorporated gene flow provided a significantly better fit for autosomal loci, which is consistent with reduced local gene flow as expected under a speciation with gene flow model. However, nucleotide diversity within chestnut teal was reduced within the region of elevated differentiation on the Z chromosome, which is more consistent with a selective sweep rather than reduced effective gene flow. Furthermore, linkage disequilibrium within this region was elevated with respects to other regions on the Z chromosome as well as more significantly elevated in chestnut teal than in grey teal. Although we cannot fully reject a model of speciation with gene flow, recent speciation seems a more plausible explanation of the nearly absent divergence of mitochondrial and autosomal DNA. Rather, these data suggest that (open full item for complete abstract)

Committee: Jeffrey Peters Ph.D. (Advisor); Scott Baird Ph.D. (Committee Member); John Stireman Ph.D. (Committee Member) Subjects: Biology

Doctor of Philosophy, Miami University, 2015, Biology

Species conservation is an enormously complex task, which includes identification of phenomena that affect the loss, maintenance, and restoration of biodiversity and advocate for sustaining evolutionary processes that promote all levels of biological organization. Endangered species conservation requires a comprehensive approach to evaluate the conservation status of a given species, develop optimal recovery plans, and establish quantitative recovery criteria, in order to remove the necessity of protection. In my dissertation, I demonstrate such a comprehensive approach for evaluating the conservation status of two imperiled freshwater mussel species: Cumberlandia monodonta and Popenaias popeii, and providing guidance for development of species recovery plans. I characterized novel microsatellite markers for the species in order to assess population genetic diversity and structure (Chapter 1 and 3). I assessed fine-scale population structure of C. monodonta and used ecological and genetic simulations to investigate the effects of future climate change on distributional shifts in suitable habitats and population genetic connectivity (Chapter 2). I also investigated evolutionary history and genetic structure of P. popeii and used long-term mark-and-recapture monitoring to determine population dynamics (Chapter 4 and 5). I used demographic and population genetic information acquired from the previous chapters to develop recovery strategies for these species (Chapter 6). Using a large number of polymorphic microsatellite markers for both species, I revealed that climate change during the mid-to-late-Pleistocene likely shaped current distribution and genetic structure in both species. Current genetic structure of C. monodonta is likely a consequence of connectivity of suitable habitat; however, future climate change will likely reduce connectivity across populations. Climate change during the mid-to-late Pleistocene caused regional and local population structures of P. p (open full item for complete abstract)

Committee: David Berg (Advisor); Bruce Cochrane (Committee Member); Thomas Crist (Committee Member); Brian Keane (Committee Member); Richard Moore (Committee Member) Subjects: Biology; Conservation; Ecology; Freshwater Ecology; Genetics

Doctor of Philosophy, The Ohio State University, 2005, Horticulture and Crop Science

Studies were conducted at the plant, population, and community level to address questions concerning (1) seed germination in Alliaria petiolata (2) weed community composition and structure in response to tillage, rotation and herbicide, and (3) variation in Abutilon theophrasti. Alliaria petiolata seeds are dormant at maturity, requiring approximately 90 to 105 days cold-moist stratification at 4 to 5 °C for germination to occur. Mechanically scarified, and H2O2 and H2SO4 treated seeds germinated within 35 days when GA3 was applied exogenously. The composition of the weed-seedbank community was characterized 35 years after the implementation of a long-term study involving cropping sequence (continuous corn, corn-soybean, corn-oat-hay) and tillage system (conventional-, minimum-, and no-tillage). Values of S, J, and H' recorded for all combinations of the three-crop sequence were typically greater than the values of S, J, and H' reported for either the one and two-crop rotations. As the intensity of soil disturbance decreased, values for S increased. Mean germinable weed seed density was greatest in the no-tillage treatments across rotations and years. Results suggest that the weed seed community in a corn-oat-hay rotational system differs in structure and composition from communities associated with continuous corn and corn-soybean systems. There is concern that the widespread use of genetically-modified glyphosate-tolerant crops (GTCs) will alter agricultural weed community dynamics with respect to glyphosate-tolerance and emergence phenology. Species associated with individual tillage and rotation treatments were not different from species recorded in the same plots prior to the exclusive use of GTCs and glyphosate, suggesting that significant changes in weed community composition and structure have not occurred. Abutilon theophrasti is a noxious weed in modern row-crop agriculture. This study characterized the morphological, phonological, and genetic variation ve (open full item for complete abstract)

Committee: John Cardina (Advisor) Subjects: Agriculture, Agronomy

Doctor of Philosophy (PhD), Ohio University, 2012, Curriculum and Instruction Science Education (Education)

The purpose of this study was to explore student changes in conceptual development, epistemology, and motivations when evolution concepts are embedded and explicit reflective discourse is used in a unit for population ecology. The two research problems were: 1) What changes are observed in student's conceptual development, epistemology, and motivations when there is explicit reflective discourse within a population ecology unit with embedded evolution?, and 2) In what ways does explicit reflection influence students' mental models within a population ecology unit with embedded evolution? This mixed-method, quasi-experimental study assessed two regular high school biology classes in a small, urban, Midwestern high school. Students in this study had not studied evolution within any formal chapters, but had been immersed in a curriculum with embedded evolution. The study was conducted over a four-week period in a population ecology unit near the beginning of second semester. Instruction emphasized basic conceptions in population ecology. Five key intervention activities included evolutionary concepts as part of an embedded curriculum. The independent variable was explicit reflective discourse with one or two intervention questions after completion of these activities. Data included pre- and posttest surveys measuring (a) evolutionary understanding of natural selection, (b) science beliefs, and (c) science motivations. Written artifacts included (a) explanations to scenarios, (b) pre- and post-argument reflections revealing student's science beliefs and science motivations resultant from two argumentations, and (c) three, pre-, post-, and 6-week final concept maps constructed from 12 concepts. All data sources provided descriptive data. Conceptual change was interpreted from an ontological, epistemological, and motivational perspective. The experimental class receiving explicit reflective discourse showed greater overall increases in conceptual development. Students in (open full item for complete abstract)

Committee: Ralph Martin PhD (Committee Chair); Teresa Franklin PhD (Committee Member); John Henning PhD (Committee Member); Jerry Johnson EdD (Committee Member) Subjects: Behavioral Psychology; Biology; Cognitive Psychology; Curricula; Curriculum Development; Education; Educational Psychology; Epistemology; Pedagogy; Science Education; Secondary Education; Teaching