Graduate Theses & Dissertations

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Fish and invertebrate use of invasive Phragmites in a Great Lakes freshwater delta
Invasive Phragmites australis ssp. australis (herein “Phragmites”) has established and rapidly spread throughout many coastal areas of the Great Lakes. Known to displace native vegetation communities as it forms large, monotypic stands, Phragmites has a bad reputation when it comes to losses of biodiversity and habitat provision for wildlife. However, the extent to which Phragmites provides habitat for fish and invertebrates in coastal freshwater wetlands remains relatively unquantified. Thus, this study assessed whether fish assemblages and invertebrate communities in stands of Phragmites differ from those in stands of two native emergent vegetation communities, Typha spp. and Schoenoplectus spp. The findings showed significant differences in habitat variables among the vegetation communities in terms of water depth, macrophyte species richness, stem density and water quality. While abundance of the functional feeding group filterer-collectors was found to be significantly less in stands of Phragmites when compared to Schoenoplectus, no difference was observed in invertebrate taxa richness among vegetation communities. Lastly, no difference in fish assemblage or invertebrate community was detected when using multivariate analyses, implying that invasive Phragmites provides habitat that appears to be as valuable for fish and invertebrates as other emergent vegetation types in the St. Clair River Delta. The findings of this study will ultimately benefit the literature on invasive Phragmites and its role as fish habitat in freshwater wetlands, and aid management agencies in decisions regarding control of the invasive species. Author Keywords: aquatic invasive species, aquatic macroinvertebrates, freshwater fish, freshwater wetlands, nMDS, Phragmites
Syrphidae (Diptera) of northern Ontario and Akimiski Island, Nunavut
Syrphids, also known as hover flies (Diptera: Syrphidae) are a diverse and widespread family of flies. Here, I report on their distributions from a previously understudied region, the far north of Ontario, as well as Akimiski Island, Nunavut. I used samples collected through a variety of projects to update known range and provincial records for over a hundred species, bringing into clearer focus the distribution of syrphids throughout this region. I also analysed a previously un-tested trap type for collecting syrphids (Nzi trap), and report on results of DNA analysis for a handful of individuals, which yielded a potential new species. Author Keywords: Diptera, Ontario, range extension, Syrphidae
Role of Policy in Arctic Food (In)Security
Hunger is a significant concern in Canada, and even more so in the North, with 52% of Inuit adults in Arctic regions experiencing some level of food insecurity in 2012. Policy deficiencies are argued to, at the least, be partly responsible for this issue. This qualitative exploratory project aimed to answer the question: What is the role of food-related policy(ies) in household food security? A review and analysis of policy documents and academic literature at three jurisdictional levels, using the case of food insecurity in Nunavik, Québec, was conducted. The study identified 281 policies facilitating and 139 policies acting as barriers to food security. The highest proportion (27%) of facilitators related to economic accessibility of food and the highest proportion of barriers (93%) related to political accessibility of food. Only one previously identified factor influencing household food security in the region had a corresponding policy barrier associated with it. The study suggests that what is considered ‘food policy’ differs significantly between jurisdictions. Many of the same policies that act to facilitate some aspects of food security act as barriers to others. Policy barriers tend to be difficult to identify by their very nature. As a result, policy plays a complicated role in Nunavik food security status, representing a positive influence in some regards and a negative one in others. Author Keywords: Arctic, Food, Food security, Inuit, Nunavik, Policy
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:
Contemporary adaptive shifts in the physiology and life history of Pumpkinseed (Lepomis gibbosus) introduced into a warm climate
Contemporary evolution has the potential to help limit the biological impact of rapidly changing climates, however it remains unclear whether wild populations can respond quickly enough for such adaptations to be effective. In this thesis, I used the introduction of native North American Pumpkinseed (Lepomis gibbosus) into the milder climate of Europe over 140 years ago, as a 'natural' experiment to test for contemporary evolution to a change in climate in wild populations. In 2008, four outdoor pond colonies were established in central Ontario using adult Pumpkinseed from two native Canadian populations, and two non-native populations from northeastern Spain. By raising native and non-native Pumpkinseed within a common environment, this design minimized the impact of phenotypic plasticity on differential trait expression, and allowed me to interpret differences in the phenotype among pond-reared Pumpkinseed as evidence of genetic differences among populations. I demonstrated that Canadian and Spanish Pumpkinseed have similar thermal physiology except when acclimated to seasonally warm temperatures; trait differences are consistent with Spanish Pumpkinseed being better adapted to a warmer climate. Populations also had similar overwintering ecology, however some differences, such as higher survival under starvation conditions and greater energetic benefits associated with winter feeding, indicated that Canadian populations are better adapted to harsh winter conditions typical of the native range. Finally, I determined that the relatively fast life history expressed in wild European Pumpkinseed is largely driven by plastic responses to the local environment; however, the higher reproductive investment by European populations has a genetic basis. Most climate change research considers taxa that are expected to be negatively impacted by warming: my research demonstrates that even warm-tolerant taxa that are unlikely to experience strong climatic selective forces can respond to a warming environment through evolutionary changes. The potential for adaptive contemporary evolution in warm-tolerant taxa should be taken into account when predicting future ecosystem effects of climate change, and when planning management strategies for species introduced into novel climates. Author Keywords: climate change, contemporary evolution, fish, non-native species, thermal biology, winter ecology
An Application of Virgilio Enriquez's Indigenization Method on Filipino-Canadian Discourse
In Disturbing Invisibility (Coloma, McElhinny, Tungohan, Catungal, Davidson, 2012), the most comprehensive book on Filipino-Canadian studies to date, issues were identified in the afterword as to how Filipino-Canadian studies relates to indigenous identity. This thesis attempts to address this issue by applying Enriquez’s (1992) Indigenization Method onto Filipino-Canadian discourse. It attempts to do this by: exploring the colonial context and history in the Philippines and its effect on the formation of a Filipino indigenous identity; exploring Filipino indigenous thought as described by Enriquez (1992) in his seminal book From Colonial to Liberation Psychology; understanding Filipinos in Canada with the inclusion of literature from Filipino-American studies and the Filipino Indigenization movement; and how orienting Filipino-Canadian discourse with the indigenous concepts brought forward by Enriquez might look like, with emphasis on how Filipino-Canadian discourse could interact with Indigenous issues relating to Indigenous People in Canada today. It becomes clear that the Filipino Indigenization movement has reached grassroots Filipino organizations in Canada, and that uncritically ignoring their own Filipino indigenous roots would be denying themselves the unique cultural gifts that those roots provide. As being both Filipino and Canadian, Filipino-Canadians who seek to reclaim their indigenous roots would find that the indigenous concept of kapwa (“the self in the other”) would encourage an examination of issues pertaining to Indigenous People in Canada as commonalities exist in their experiences with colonization. Author Keywords: Canada, discourse, Filipino-Canadians, indigenization, indigenous, Philippines
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
Molecular Composition of Dissolved Organic Matter Controls Metal Speciation and Microbial Uptake
Aquatic contaminant mobility and biological availability is strongly governed by the complexation of organic and inorganic ligands. Dissolved organic matter (DOM) is a complex, heterogeneous mixture of organic acids, amino acids, lipids, carbohydrates and polyphenols that vary in composition and can complex to dissolved metals thereby altering their fate in aquatic systems. The research conducted in this doctoral dissertation addresses 1) how DOM composition differs between phytoplankton taxa and 2) how DOM composition affects metal speciation and its subsequent microbial bioavailability in laboratory and field conditions. To accomplish this, a series of analytical methods were developed and applied to quantify thiols, sulphur containing DOM moieties, and the molecular composition of DOM. The works presented in this thesis represents one of the first comprehensive and multipronged analyses of the impact of phytoplankton metabolite exudates on microbial metal bioavailability. This dissertation demonstrated the analytical versatility of high-resolution mass spectrometry as a tool for compound specific information, as well as having the capabilities to obtain speciation information of organometallic complexes. The work presented in this PhD strengthens the understanding compositional differences of both autochthonous and allochthonous DOM and their effects on metal biogeochemistry. Author Keywords: Dissolved Organic Matter, Mercury, Metal Accumulation, Phytoplankton, Spring Melts, Thiol
An Investigation of Rare Earth Element Patterns and an Application of Using Zn and Cd Isotope Ratios in Oysters to Identify Contamination Sources in an Estuary in Southern China
Environmental monitoring and investigation of metal biogeochemical cycling has been carried out in the Pearl River Estuary (PRE), an important and complex system in Southern China. In this study, rare earth element (REE) patterns as well as isotope ratios (i.e., Zn and Cd) were evaluated as tools to identify contamination sources in environmental compartments (i.e., water and suspended particles (SP)) as well as in oysters collected from estuarine sites. Results show elevated concentrations (also called anomalies) of Pr, Nd, Dy and Ho, relative to other REE elements, in water samples, potentially from REE recycling and other industrialized activities in this area. Unlike water samples, no REE anomalies were found in SP or oysters, suggesting that the dominate REE uptake pathway in oysters is from particles. Secondly, site to site variations in Zn isotope ratios were found in water and SP, showing the complexity of the source inputs in this area. Also, in estuarine locations, larger spatially differences in Zn isotope ratios were found in water collected in wet season than those in dry season, which may due to mixing of different source inputs under the water circulations in different seasons. A series of laboratory experiments were conducted during which changes in Zn isotope ratios were measured during uptake under varying salinity and Zn concentrations and during depuration. Neither in vivo Zn transportation among the various tissues within the oysters nor water exposure conditions (i.e., different salinities or Zn concentrations) caused Zn isotopic fractionation in the oysters. Cd and Zn isotope ratios were also determined in oysters obtained from the PRE. Large variations in Cd and Zn isotope ratios suggest that oysters were receiving contaminants from different input sources within the PRE. A consistent difference (approximately 0.67‰) was observed for Zn isotope ratios in oysters collected from the east side of the PRE compared to those from sampling locations on the western side of the PRE, suggesting different Zn sources in these two areas. Ultimately, by combining biogeochemistry with physiology, this study represents a first attempt to assess pollution status, monitor contaminants using oysters and model/identify contamination sources using both REEs and metal isotope ratios. Author Keywords:
Socioloegal Mediation of Rave Sound System Technologies
The central scholarly contribution of this dissertation develops through bringing the theories of Michel Foucault to bear in a sociolegal study of rave culture's criminalization by the United Kingdom's 1994 Criminal Justice and Public Order Act. My methodology develops rave as a cultural keyword. This keyword navigates through a quasi-materialist definition of rave as a cultural codification of sound system technologies. I theorize the way in which sociocultural discourse indexes aestheticized representations and the cultural mythologies that rave sound system's technical mediation generate. These ideas trace the facticity of the legal documentation of rave’s criminalization. I inform this sociolegal history by situating Foucault's work on the genealogy of liberalism as a practical toolkit for associating the legal discourse on rave culture with the genealogy of festival. This opens up a dialogue with the work of Mikhail Bakhtin's theorizing of the festival’s ambivalent political climate. Such ideas are useful in documenting rave as an enduring mimicry of the tension between State and civil society. Pieter Bruegel the Elder’s 1559 painting, “The Fight Between Carnival and Lent”, captures this tension beautifully. The aptness of reading rave's criminalization in relation to Bruegel’s portrayal of landscape is accomplished by returning to Foucault, who defines liberalism's political technologies in relation to Judaeo-Christian precedents. I explore how these political technologies, pastoral power in particular, are helpful in tracing rave's genealogical relation to the festival's sociotechnical cartography. Author Keywords: Bakhtin, Carnival, Christianity, Festival, Liberalism, Materialism
How Abiotic and Biotic Factors Can Alter the Competitive Landscape in an Aggressive Species Complex (Genus
Competition is known to impact population dynamics through both indirect and direct interactions, and direct interactions can often lead to injury in one or both parties. As such, response to injury through tissue regeneration can be important for surviving post-competitive interaction. However, the impacts of outside factors like temperature and genome size (e.g. polyploidy) are not well studied, especially in syntopic systems. We addressed this knowledge gap by comparing regeneration rates of diploid Ambystoma laterale and triploid unisexual Ambystoma at two ecologically-relevant temperatures. Environmental factors appeared to have stronger effects on regeneration than ploidy level, but overall mass was impacted more strongly by ploidy level. Interestingly, there was an interaction between temperature and time within unisexuals that was absent when comparing different ploidy levels, implying temperature has a more complex effect on polyploids. This study supports the hypothesis that polyploid organisms are better equipped to respond to shifts in their environments, which can give them a competitive advantage at the northern range limit of this species complex. Author Keywords: Ambystoma, Genome dosage, Hybrid vigor, Polyploidy, Thermal optimum, Tissue regeneration

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