- Collections Home
- Alumni House Collection
- Arthur Virtual Archive
- Faculty Research Collection
- Journal GenObs
- Margaret Laurence Collection
- Stories of Resistance, Resurgence, and Resilience in Nogojiwanong / Peterborough
- Trent Community Research Centre Project Collection
- Trent University Academic Calendar Collection
- Trent University Archives
- Trent University Graduate Thesis Collection
- University Heritage Collection
Graduate Theses & Dissertations
Pages
-
- Temporo-spatial patterns of occupation and density by an invasive fish in streams
- Since its introduction to North America in the 1990s, the Round Goby has spread throughout the Great Lakes, inland through rivers and is now moving into small tributary streams, a new environment for this species in both its native and invaded ranges. I explored density and temporal occupation of Round Gobies in four small streams in two systems in south-central Ontario, Canada in order to determine what habitat variables are the best predictors of goby density. Two streams are tributaries of Lake Ontario and two are tributaries of the Otonabee River, and all of these streams have barriers preventing upstream migration. I found that occupation and density differed between the systems. In the Otonabee River system, Round Gobies occupy the streams year round and the most important factor determining adult density is distance from a barrier to upstream movement, with the entire stream occupied but density highest next to the barriers. In the Lake Ontario system, density is highest at mid-stream and Round Gobies appear to occupy these streams mainly from spring to fall. Adult density in Lake Ontario tributaries is highest in sites with a high percentage of cobble/boulder and low percentage of gravel substrate, while substrate is less important in Otonabee River tributaries. Occupation and density patterns may differ due to contrasting environmental conditions in the source environments and distance to the first barrier preventing upstream movement. This study shows diversity in invasion strategies, and provides insight into the occurrence and movement patterns of this species in small, tributary streams. Author Keywords: biological invasion, Generalised Additive Mixed Model, habitat, Neogobius melanostomus, Round Goby, stream
-
- Influence of Canopy Water Partitioning on the Isotopic Signature of Plant Water in a Mixed Northern Forest
- This study seeks to clarify the way in which the differing canopy characteristics among tree species influence the partitioning of precipitation, and therefore the source of water available for plant water uptake, in the Plastic Lake catchment near Dorset, ON. Three dominant tree species were compared: red oak (Quercus rubra), eastern white pine (Pinus strobus), and eastern hemlock (Tsuga canadensis). Above-canopy precipitation, throughfall, stemflow, and soil water content were monitored weekly from June 2016 until October 2016 and the 18O and 2H isotopic signatures of each were analyzed. Plant water and bulk soil water samples were also collected from five trees of each species at five stages of the growing season to compare the isotopic signature of xylem water to that of their surrounding soils. Both plant water and bulk soil water displayed evidence of isotopic fractionation; however, plant water was more depleted in δ2H and δ18O than bulk soil water. Water interacting with the tree canopies as throughfall and stemflow did not display significant evidence of isotopic fractionation. This suggests that the vegetation could have accessed an isotopically distinct source of water stored within the soil or that an unknown isotopic fractionation process occurred throughout this study. Author Keywords:
-
- Sextual Consent
- The purpose of the current study was to explore the relationships between sexting, perceptions of sexual consent, and nonconsensual sexual experiences (NSEs). Participants consisted of 100 community members and 851 undergraduate students enrolled at Trent University. It was found that males were more likely than females to interpret ambiguous sexual scenarios as consensual, but consent perceptions were not influenced by sexting. When examining past personal experiences, males interpreted received sext messages as an indicator of consent significantly more than females, while females were more likely to interpret received messages as more harassing. NSEs were significantly related to sexting behaviours: those who engage in sexting were more likely to also have experienced a NSE, and 20.5% of participants in the current study reported having experienced a NSE with a consensual sexting partner. The current study has important implications for the future of sexting research, practice, and policy. Author Keywords: nonconsensual sexual experiences, sexting, sexual assault, sexual consent, sexual harassment
-
- Eco-evolutionary Dynamics in a Commercially Exploited Freshwater Fishery
- Fisheries assessment and management approaches have historically focused on individual species over relatively short timeframes. These approaches are being improved upon by considering the potential effects of both broader ecological and evolutionary processes. However, only recently has the question been raised of how ecological and evolutionary processes might interact to further influence fisheries yield and sustainability. My dissertation addresses this gap in our knowledge by investigating the role of eco-evolutionary dynamics in a commercially important lake whitefish fishery in the Laurentian Great Lakes, a system that has undergone substantial ecosystem change. First, I link the timing of large-scale ecological change associated with a species invasion with shifts in key density-dependent relationships that likely reflect declines in the population carrying capacity using a model selection approach. Then, using an individual-based model developed for lake whitefish in the southern main basin of Lake Huron, I demonstrate how ecosystem changes that lower growth and recruitment potential are predicted to reduce population productivity and sustainable harvest rates through demographic and plastic mechanisms. By further incorporating an evolutionary component within an eco-genetic model, I show that ecological conditions also affect evolutionary responses in maturation to harvest by altering selective pressures. Finally, using the same eco-genetic model, I provide a much-needed validation of the robustness of the probabilistic maturation reaction norm (PMRN) approach, an approach that is widely used to assess maturation and infer its evolution, to ecological and evolutionary processes experienced by exploited stocks in the wild. These findings together highlight the important role that ecological conditions play, not only in determining fishery yield and sustainability, but also in shaping evolutionary responses to harvest. Future studies evaluating the relative effects of ecological and evolutionary change and how these processes interact in harvested populations, especially with respect to freshwater versus marine ecosystems, could be especially valuable. Author Keywords: Coregonus clupeaformis, density-dependent growth, fisheries-induced evolution, individual-based eco-genetic model, Lake Huron, stock-recruitment
-
- Politics of Feasting
- The goal of this thesis is to explore the role that civic (i.e. state-sponsored) feasting and drinking played in early polis (pl. poleis), or city-state formation on Crete in the Early Iron Age to Archaic transition, ca. 700-500 BCE. Using the two recently excavated civic feasting structures at the site of Azoria as a model for both “inclusive” and “exclusive” forms of civic feasting, this project compares and contrasts the role that it played at a number of other sites in central and east Crete. In order to categorize the structures as either inclusive or exclusive, all forms of published evidence were examined including the buildings’ architecture and the socially valued goods and ceramics found within the structures. Ultimately, this project demonstrates that in the 8th century BCE, inclusive feasting rituals and association with the past were used as means of creating and maintaining a strong group identity, which paved the way for the use of more exclusive practices in the 7th century BCE, where sub-group identities and alliances were formed amongst members of the larger group. However, at the sites where there was evidence for multiple civic feasting venues it appears that by the 7th century BCE, the interplay of both inclusive and exclusive forms of feasting was crucial to the process of identity formation for the citizens of these proto-poleis. Author Keywords: Archaic Crete, Commensality, Feasting, Identity Formation, Polis formation
-
- Effect of Nitrosative Stress on Heme Protein Expression and Localization in Giardia Intestinalis
- The parasitic protist Giardia intestinalis has five heme proteins: a flavohemoglobin and several isotypes of cytochrome b5. While the flavohemoglobin has a role in counteracting nitric oxide, the functions of the cytochromes (gCYTb5s) are unknown. In this study, the protein level and cellular localization of three gCYTB5 isotypes (gCYTb5-I, II and III) and flavohemoglobin were examined in Giardia trophozoites exposed to three nitrosative stressors at two different concentrations: nitrite (20 mM, 0.5 mM); GSNO (2 mM, 0.25 mM) and DETA-NONOate (2 mM, 0.05 mM). An increase in protein levels was observed for gCYTb5-II with all stressors at both concentrations. However, the effects of these nitrosative stressors on gCYTb5-I and III were inconclusive due to the variation among the replicates and the poor detection of gCYTb5- III on western blots. The protein level of the flavohemoglobin also increased in response to the three stressors at the low concentrations of stressors that were tested. Only the cellular localization of gCYTb5-I changed in response to nitrosative stress, where it moved from the nucleolus to the nucleus and cytoplasm. This response was extremely sensitive and occurred at the lower doses of the three stressors, suggesting that gCYTb5-I may be involved in a nucleolar- based stress response. Author Keywords:
-
- Trace Metal Geochemistry in Peatlands
- Peatlands can be found widely across all latitudes and play a significant role in global cycles within the earth’s biosphere. The anoxic conditions in peatlands promotes the accumulation of organic matter through decreased rates of decomposition and the storage of certain elements, which have received contaminant loading over the course of human existence, with significant increases occurring during the period of industrialization. We assessed global patterns of metal enrichment in peatlands in 439 cores distributed across 5 continents and 21 countries and measured 35 elements by depth increments and by peatland type. Global patterns in enrichment factors (EF’s) were determined for all metals with the majority of metals being found to have a median EF < 2 indicating relatively minor enrichment. Principal component analysis indicated EF’s of 6 metals (Cd, Co, Cu, Ni, Pb, and Zn), 2 metalloids (As and Sb) and Se in the upper peat horizon had similar spatial patterns among peatlands and these elements had generally the highest EF’s with many cores exceeding EF >10 and some having EF values >100. Significant differences in EF’s were found for these 9 “pollution” elements by peatland type and to a greater extent by geographic region, with higher EF values typically occurring in Europe and North America. Enrichment factors for most elements exhibited weak but significant positive correlations with modelled [1850 – present] S deposition. Estimated pools for the “pollution metals” within the 0 - 40 cm depth varied considerably, with median global pools in peat ranging from 12.9 mg m-2 (Sb) to 439 mg m-2 (Zn) for these 9 metals. Climate changes presents a significant risk to global peatland geochemistry due to expected changes in hydrologic regimes, resulting in potentially increased metal mobility though drought-induced peatland acidification, with historic areas previously impacted by industrial activities presenting the greatest risk of metal release to downstream receiving environments. Using a case study, we examined the impact of simulated 30-day drought on pore water chemistry at six sites in a peatland complex in Elliot Lake Ontario that were historically impacted by uranium (U) mining activities. All sites responded similarly to simulated drought with pore water pH significantly declining. The decline in pore water pH was likely due to increasing sulphate (SO42-) concentrations, which accompanied large increases in Al, Ni, Cu, Pb, Zn, and U. Dissolved organic carbon (DOC) increased, which may further enhance Al, Cu, and U mobility as these metals are strongly complexed by organic acids. Metal partitioning (Kd) values could be significantly predicted by pH and DOC although the strength of the relationship varied considerably among sites. Multiple linear regression and the inclusion of SO4-2 improved predictions, indicating that declines in pH as a result of SO4-2 and H+ production primarily governs metals and U partitioning in peatland soils. The results from both studies show that metal enrichment in global peatlands is highly variable, with northern peatlands in industrialized areas presenting the greatest risk of metal release to downstream surface waters based on expected hydrologic impacts from climate change due to historical and on-going metal and S deposition. Author Keywords: Acidification, Climate Change, Drought, Enrichment Factors, Global, Peatlands
-
- Biosynthesis and impact of cytokinins on growth of the oyster mushroom, Pleurotus ostreatus
- The oyster mushroom, Pleurotus ostreatus, is one of the most widely cultivated edible basidiomycetes. It has gained increased attention for its economic, environmental, and medicinal properties. While a lot is known about cytokinins (CKs) and their actions at the molecular and cellular levels in plants, much less is known about the function of CKs in other kingdoms. Cytokinins, which have been detected in several fungal species, play a role in pathogenic attack against plants or during plant growth promotion by plant beneficial microbes; however, the role of CKs in fungal physiology, separate from plant associations remains largely unknown. This thesis focuses on the occurrence of fungal-derived CKs in P. ostreatus when grown in vitro as submerged or aerial mycelium. Cytokinin profiling by UHPLC-HRMS/MS revealed that P. ostreatus produces CKs and that the tRNA degradation pathway is the main source of these molecules. CK dynamics within fungal growth supported previous evidence, which suggested that tRNA degradation products have a role in the physiological development of fungi for which CKs act as fungal growth regulators. A second component of the thesis demonstrated that P. ostreatus responds to exogenous applications of aromatic and isoprenoid CKs and their effects were dependent on the dose and CK type. N6-Benzyladenine (BAP), Kinetin (KIN), N6-isopentenyladenine (iP), and trans-zeatin (tZ) bioassays revealed hormone-type responses (hormesis: biphasic response). At low doses, mycelium growth could be stimulated, whereas, at high doses only inhibitory effects were observed. This stimulation/inhibition was observed whether the measured response was an increase/decrease of aerial mycelium colony diameter, biomass accumulation or a change in mycelium morphology as compared to the controls. Results indicated there is potential to alter mycelium growth and development of P. ostreatus; thus, CKs may play the role of a “mycohormone” and may be specifically helpful for medicinal fungi by increasing growth and efficiency to produce many biologically active substances with valuable medical and environmental applications. Author Keywords: cytokinins, fungal-derived CKs, hormesis, mycelium, mycohormone, Pleurotus ostreatus
-
- Biogeography of Carabidae (Coleoptera) in the Boreal forest
- Basic biogeographic information is lacking for many species, such as where species are found, and how they dispersed there. Using ground beetles collected during 2008-2015 from across northern Ontario and Akimiski Island, Nunavut, I present new information on ground beetle distribution in this eastern Nearctic boreal forest, including 2 first Canadian records, 9 first provincial and 48 first territorial records, as well as 74 new records that extend the known range of many large and common ground beetles several hundred kilometres. I used these distributions to redress the knowledge gap that includes fundamental distribution data, i.e. the Wallacean shortfall, and to inform later chapters in my thesis.In Chapter 3, I examine the range expansion pattern of Carabus granulatus, a non-native species, as it spread across northeastern North America and I provide a new range record. Northern Ontario is already under threat from non-native species entering the region and it is important to conduct studies in the region before more disturbance associated with development occurs. In Chapter 4, I examine the hypothesis that northern Ontario effectively acts as a climate plateau for poikilotherms, using the predictions from Bergmann's rule as my metric. The body length of ground beetles does not appear to change over the small temperature gradient that exists across northern Ontario latitudes, supporting the climate plateau hypothesis. In Chapter 5, I test hypotheses about dispersal mechanisms that contributed to post glacial re-establishment of ground beetles using predictions of geographic distribution patterns as metrics. I found that ground beetles were likely carried downstream by rivers which aided their dispersal northward from southern refugia. I infer from the current geographic distributions that flightless ground beetle species are still expanding their range in this boreal region. Finally, I argue that there is an urgent need for more basic research on species distributions while it is still possible in regions like northern Ontario, before increased industrial and agricultural development, and expanding resource extraction projects obliterate evidence of historic ecological processes. Author Keywords: Boreal forest, Carabidae, Coleoptera, Passive dispersal, Post-glacial distribution, Range extension
-
- Electrochemical versus Chemical Oxidation of Bulky Phenols
- Phenolic compounds are used in industry, such as agriculture and biotechnology, and inevitably end up in our environment. These compounds may serve as a phenolic precursor to produce raw materials for a wide range of applications. Chemical oxidation has been the common synthetic pathway to oxidize phenols and related compounds. However, traditional chemical approaches suffer from use of harsh chemicals, waste generation, and lack of reaction selectivity. Electrochemical synthesis has emerged as an alternative method to mitigate common challenges associated with organic synthesis. Herein, electrochemical oxidation of 2,6-diphenylphenol (DPP) and 2,2-dihydroxybiphenol (DHBP) was carried out and compared to traditional chemical oxidation. Contrasted with chemical oxidation, cyclic voltammetry of DPP resulted in a range of products based on the specific potential ranges used, whereas chemical oxidation of DHBP yield a dark-coloured polymeric product. The electrooxidation and chemical oxidation of DPP and DHBP resulted in a solution colour change, indicative of the formation of new, but different products monitored by UV-vis, and characterized by nuclear magnetic spectroscopy (NMR), X-ray single crystal diffraction, IR spectroscopy, transmission electron microscopy (TEM), and gas chromatography-mass spectrometry (GC-MS). The data indicate that the synthetic outcomes are dependent on the synthetic methodology employed, and that electrooxidation and chemical oxidation can form products unique to the pathway utilized. Author Keywords: chemoselectivity, electrochemistry, phenols, radical, synthesis
-
- From Cultural Barriers to Educational Breakthroughs
- This study examines critical pedagogy as a novel approach to diversity, equity and inclusion (DEI) education at Peterborough Police Service (PPS). To begin, the present study examines hypermasculinity and isolationism as cultural traits in policing that serve as barriers to DEI education. Later, results of focus groups with PPS members that investigated negative and positive experiences with DEI training, barriers to meeting DEI education outcomes and, perceived goals of future DEI education at PPS are discussed. Drawing from findings from the literature review and focus groups, this thesis argues that critical pedagogy offers a useful framework to explore divisive subjects like systemic racism, power and privilege, colonialization, etc. and contributions of police in maintenance of the status quo. Raising the critical consciousness of PPS members by unveiling systems of domination may provide a starting point for enhancing police service to groups that are racialized and minoritized. Education of this kind may also involve a reconceptualization of the role of police as allies to marginalized communities. Author Keywords: Community, Critical Pedagogy, Diversity, Education, Police, Police Culture
-
- Beyond Beads
- Burials at the Early Bronze Age IA (c. 3700-3400) cemetery of Fifa, Jordan included a variety of grave goods including beads. These were made of glazed steatite or carnelian. This thesis utilizes use-wear analysis, SEM-EDS, XRD, and a database of 5th and 4th millennium BCE beads in order to build life-histories for Fifa’s beads. Beyond focusing on how the beads were manufactured, where they were produced, how they travelled to the Fifa cemetery, and how they were used at the cemetery, the symbolic and contextual meanings of both types of beads are also explored. I argue that Fifa’s glazed steatite beads were manufactured in Upper Egypt while its carnelian beads were produced in Northwest Arabia. Their exchange facilitated economic and social connections. Both types of beads were likely used for their protective qualities with glazed steatite also potentially assisting in the successful reincarnation of deceased subadults. Author Keywords: Beads, Carnelian, Glazed Steatite, Levantine Archaeology, Mortuary Archaeology, Use-wear Analysis