Electronic Thesis or Dissertation

The effects of parasitism on consumer-driven nutrient recycling

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Creator (cre): Narr, Charlotte, Thesis advisor (ths): Frost, Paul C, Degree committee member (dgc): Burness, Gary, Degree committee member (dgc): Sutcliffe, Jim, Degree granting institution (dgg): Trent University
Abstract:

Daphnia are keystone consumers in many pelagic ecosystems because of their central role in nutrient cycling. Daphnia are also frequently infected, and the parasites causing these infections may rival their hosts in their ability to regulate ecosystem processes. Therefore, parasitic exploitation of Daphnia may alter nutrient cycling in pelagic systems. This thesis integrates existing knowledge regarding the exploitation of Daphnia magna by 2 endoparasites to predict parasite-induced changes in the nutrient cycling of infected hosts and ecosystems. In chapter 1, I I contextualizing the integration of these themes by reviewing the development of the fields of elemental stoichiometry and parasitology. In chapter 2, we show how the bacterial parasite, Pasteuria ramosa, increased the nitrogen (N) and phosphorus (P) release rates of D. magna fed P-poor diets. We used a mass-balance nutrient release model to show that parasite-induced changes in host nutrient accumulation rates and diet-specific changes in host ingestion rates were responsible for the accelerated nutrient release rates that we observed. In chapter 3, we extended our examination of the nutrient mass balance of infected D. magna to include another parasite, the microsporidian H. tvaerminnensis. We found differences in the effects of these two parasites on host nutrient use as well as support for the hypothesis that parasite-induced changes in Daphnia N release are caused by the effects of infection on Daphnia fecundity. In chapter 4, we examined the relationship between P concentrations and the presence and prevalence of H. tvaerminnensis in rock pools along the Baltic Sea. We found that particulate P concentrations were negatively associated with the prevalence of this parasite, a result that is consistent with the increase in P sequestration of H. tvaerminnensis-infected Daphnia that we observed in chapter 3. I discuss the potential implications of the work presented in chapters 2-4 for other parasite-host systems and ecosystems in chapter 5. Overall, the research presented here suggests that parasite-induced changes in host nutrient use may affect the availability of nutrients in the surrounding environment, and the magnitude of this effect may be linked to parasite-induced reductions in fecundity for many invertebrate hosts.

Author Keywords: consumer, ingestion rates, mass-balance, nutrient-recycling, parasitism, phosphorus

2016

Testing for Interspecific Hybridization and a Latitudinal Cline Within the Clock Gene Per1 of the Deer Mouse (Peromyscus maniculatus) and the White-Footed Mouse (Peromyscus leucopus)

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Creator (cre): McKay, Michelle Meredith, Thesis advisor (ths): Wilson, Paul J, Thesis advisor (ths): Bowman, Jeff, Degree committee member (dgc): Freeland, Joanna R, Degree granting institution (dgg): Trent University
Abstract:

The recent northward expansion of the white-footed mouse (Peromyscus leucopus) in response to climatic changes provides a natural experiment to explore potential adaptive genetic variation within the clock gene Per1 in Peromyscus undergoing latitudinal shifts, as well as, the possibility of hybridization and introgression related to novel secondary contact with its sister species the deer mouse (Peromyscus maniculatus). Because clock genes influence the timing of behaviors critical for survival, variations in genotype may reflect an organism's ability to persist in different environments. Hybridization followed by introgression may increase the adaptive potential of a species by quickly generating adaptive variation through novel genetic recombination or by the transfer of species-specific alleles that have evolved in response to certain environments. In chapter 2, I used microsatellite and mtDNA markers to test for hybridization and introgression between P. maniculatus and P. leucopus and found that interbreeding is occurring at a low frequency (<1%). In chapter 3, I tested for a latitudinal cline in a polyglycine repeat located within the Per1 gene of Peromyscus and discovered a putative cline in the Per1-142 and Per1-157 allele of P. leucopus and P. maniculatus, respectively. Chapter 4, further expands upon these findings, limitations, and the lack of evidence supporting introgression at the Per1 locus. Despite this lack of evidence, it is possible that novel hybridization has or could lead to adaptive introgression of other genes, allowing for the exchange of adaptive alleles or traits that could be advantageous for range expansion and adaption to future environmental changes.

Author Keywords: Clock genes, Hybridization, Latitudinal gradient, Per1, Peromyscus, Range Expansion

2016

In situ measurements of trace metal species in the Athabasca and Mackenzie Rivers using diffusive gradient in thin films (DGT) devices

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Creator (cre): Zhu, Yu, Thesis advisor (ths): Gueguen, Celine, Degree committee member (dgc): Koprivnjak, Jean-François, Degree committee member (dgc): Aherne, Julian, Degree granting institution (dgg): Trent University
Abstract:

This study assesses the bioavailable metal (Cu, Ni, Zn, Pb) species in the Athabasca-Mackenzie watersheds using diffusive gradient in thin films (DGT) devices. Metal toxicity is not only based on the concentration of metal in natural waters, but also on the nature of metal species. Four main forms in aquatic systems are: free ion, inorganic species, DOM bound (humic) species and metal colloidal species. The free ion and inorganic species and very small humic species are known as DGT-labile species and, are considered to be more bioavailable to micro-organisms due to the size and thus may be toxic to microorganisms. In this study, DGT devices were applied to (1) monitor the DGT-labile metal species in the lower Athabasca River and the Mackenzie River watershed and (2) assess the DGT-labile metal concentrations on temporal and spatial scales. In the lower Athabasca River, comparison between the DGT results and the Windermere Humic Acid Model (WHAM) calculation indicated good agreements for all metals when the precipitated iron(III) hydroxide was assumed as an active binding surface. No significant variations in labile species were found over 2003-2012 (RAMP database) despite the development of oil sands. In the Mackenzie River, no significant difference in DGT-labile metal concentrations and DOC concentrations was found in yearly basis 2012-2014. Only DOC was lower in August (6.98 and 3.85 ppm, respectively; p< 0.05) due to dilution from heavy rain events. Spatially, DGT-labile Cu and Ni in the downstream Mackenzie River were higher than upstream (1.79 and 0.58 ppb for Cu, 1.68 and 0.77 ppb for Ni, 4.06 and 6.91 ppm for DOC; p < 0.05). Overall the in situ measurements of metals constitute a benchmark for future studies in water quality and be helpful in environmental management in Alberta and the Northwest Territories in Canada.

Author Keywords: Athabasca River, DGT, Mackenzie River, Speciation, Trace Metal, WHAM

2016

Practicing and Rewarding Task-Relevant Motor Variability to Optimize Motor Performance

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Creator (cre): Coltman, Susan Kelly, Thesis advisor (ths): Brown, Liana E, Degree committee member (dgc): Lehmann, Hugo, Degree granting institution (dgg): Trent University
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It is universally accepted that human motor performance is variable in both its timing and spatial qualities. However, it is unclear to what extent motor variability impedes performance when learning a new skill and to what extent it enables our ability to learn. The first experiment examined whether performance during a test task depended on whether participants practiced to constrain or vary the task-relevant parameter. Participants used their right hand to make simple point-to-point movements. Results demonstrated the importance of paying attention to test task demands to evaluate which form of practice is most beneficial. The second experiment examined whether levels of variability could be manipulated using a reward-based paradigm to enhance learning when adapting to a perturbation of a simple visually-guided reaching movement. A reward-based feedback task was designed to encourage exploration along the task-relevant dimension, specifically movement direction variability. Overall, I did not find any significant results.

Author Keywords: Adaptation, Motor Control, Motor Learning, Reaching

2016

Long-Term Population Dynamics of an Unexploited Lacustrine Brook Trout (Salvelinus fontinalis) Population

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Creator (cre): Brown, Erin Nicole Danielle Pallette, Thesis advisor (ths): Ridgway, Mark S, Thesis advisor (ths): Wilson, Chris C, Degree granting institution (dgg): Trent University
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Long-term studies of demographic processes such as survival and abundance conducted in unexploited systems provide unique insight into the natural population ecology of fish, but are rarely available. I used historical tagging records of a sanctuary population of brook trout (Salvelinus fontinalis) in Algonquin Park, Ontario to investigate long-term population dynamics in an unexploited population. Adult brook trout in Mykiss Lake (23.5ha) were surveyed and tagged biannually (May and October) between 1990 and 2004. Open-population capture-mark-recapture models were used to test the importance of time, size, sex and season on estimates of apparent survival and abundance. Seasonal population growth and recruitment were estimated and compared with large-scale climate indices. Time-dependent survival and abundance estimates fluctuated, with distinct periods of increase. Population growth and recruitment were positively correlated with summer NAO and ENSO values, whereas survival was negatively correlated. Seasonally, larger individuals experienced higher apparent survival during winter and decreased survival during summer. These findings provide valuable insights into the natural demography of unexploited brook trout populations, and should help inform sustainable management of inland fisheries.

Author Keywords: capture-mark-recapture, long-term, population dynamics, Salvelinus fontinalis, seasonal variation, survival

2016

Robert Bringhurst and Polyphonic Poetry: Literature as Participation in Being

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Creator (cre): Cecchin, Scott Richard, Thesis advisor (ths): Steffler, Margaret, Degree committee member (dgc): Popham, Elizabeth, Degree granting institution (dgg): Trent University
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Robert Bringhurst states that polyphonic art is a faithful, artistic reflection of the multiplicity of the world's ecosystems. This ecocritical perspective recognizes that human art informs our understandings of the world, and therefore artists have a moral obligation towards that world. In Chapter One I argue that mimesis should be reclaimed as a useful literary category since all art, regardless of intentions, has an effect on both culture and the natural world. In Chapter Two I argue that by reconnecting publishing craft and philosophy, our books can serve to bring us more in tune with the structures of the natural world. I conclude in Chapter Three by asking how a counterpublic consciousness can be cultivated, and how Bringhurst's mission of transforming culture might be fully realized. Altogether, this view of literature offers an antidote to Western culture's destructive tendencies towards the natural world.

Author Keywords: Bringhurst, ecocriticism, mimesis, poetry, polyphony, typography

2016

Phylogeography and Genetic Structuring of Moose (Alces alces) Populations in Ontario, Canada

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Creator (cre): Price, Glynis Nicola Rose, Thesis advisor (ths): Saville, Barry, Degree committee member (dgc): Murray, Dennis, Degree committee member (dgc): Bowman, Jeff, Degree granting institution (dgg): Trent University
Abstract:

Moose are an iconic species, known for their large size and impressive antlers. Eight subspecies are classified in circumpolar regions of the planet - four in North America. Two subspecies are similar in shape and size, the north-western moose (Alces alces andersoni) and the eastern moose (Alces alces americana). It was previously believed that these two subspecies meet in northern Ontario. Earlier genetic population studies used a small number of samples from Ontario, primarily in broad studies covering all of North America.

A comprehensive genetic study of moose populations in Ontario has not previously been conducted. We examined the genetic diversity and population structure at 10 polymorphic loci using 776 samples from Ontario, as well as outgroups from representative populations – Manitoba/Cape Breton, representing A. a. andersoni, and New Brunswick/Nova Scotia, representing A. a. americana. Results indicated three genetic populations in the province, in north-western Ontario, north-eastern Ontario and south-central Ontario. RST values, compared against both FST and Jost's D values for phylogenetic analyses, indicated no phylogenetic pattern which suggests no subspeciation present in the province.

Population movement patterns in Ontario were studied. Gene flow was estimated using genetic and spatial data. Isolation by distance was only seen within the first distance class of 100 kilometres and then not seen again at further distances, indicating that moose display philopatry. There were very few migrants travelling across the province, with a greater number moving gradually north and west, towards better habitat and food sources.

A forensic database in the form of an allele frequency table was created. Three loci showed very low levels of heterozygosity across all three populations. Probability of identity was calculated for the three populations and quantified. Samples with known geographic origins were run against the database to test for sensitivity, with identification of origin occurring at an accuracy level between 87 and 100%.

Within Ontario, there are not two different subspecies, as previously believed, but two different populations of the same subspecies meeting in northern Ontario. The genetic data does not support previous research performed in Ontario. The sample sizes in our research also provide a more comprehensive view of the entire province not seen in any previous studies. The comprehensive research enabled the building of a reliable forensic database that can be used for both management and forensic purposes for the entire province.

Author Keywords: Alces alces, Genetic Diversity, Moose, Ontario, Phylogeography, Subspecies

2016

Eros noir: Transgression in the Aesthetic Anthropology of Georges Bataille, Hans Bellmer, and Pierre Klossowski

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Creator (cre): Bell, Jeremy Owen, Thesis advisor (ths): Bordo, Jonathan, Thesis advisor (ths): Thomas, Yves, Degree committee member (dgc): Junyk, Ihor, Degree committee member (dgc): Wernick, Andrew, Degree granting institution (dgg): Trent University
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The dissertation explores the aesthetic anthropology of Georges Bataille and his collaborators in the Collège de Sociologie, a distinguished group of intellectuals including Roger Caillois, Michel Leiris, Pierre Klossowski, and Walter Benjamin among others. At the dissertation's outset the role, influence, discovery and indeed invention of the Marquis de Sade as the almost mythic prefiguring for so much French aesthetic thought in the period beginning after World War One and up until even the present day is advanced. Before Freud in Vienna, Sade in Paris: the central thematic axis of the following addresses Eros noir, a term for reflecting on the danger and violence of sexuality that Freud theorizes with the "death drive." The deconstruction of the nude as an object and form in particular in the artwork of Hans Bellmer and the writing and art of Pierre Klossowski comprises the latter two chapters of the dissertation, which provides examples of perversion through the study of simulacra and phantasms. The thwarted pursuit of community in the vacated space of Nietzsche's death of a God is a persistent leitmotif of the following in the account it offers of the thought of Georges Bataille and other members of the Collège de Sociologie. Eros noir, at the fatal cusp between ascendant manifest sex and a latent diminished Christianity, underwrites much of the French intellectual contribution to the symbology of cultural modernism.

Author Keywords: Bataille, Georges, 1897-1962, Collège de Sociologie, Eroticism, Sade, marquis de, 1740-1814, Surrealism, The Uncanny

2015

Assessing the Potential for Contamination of Lakes from Upwelling of Arsenic-Laden Groundwater Through Sediments

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Creator (cre): Lock, Alan S., Thesis advisor (ths): Wallschläger, Dirk, Thesis advisor (ths): Belzile, Nelson, Degree committee member (dgc): Belzile, Nelson, Degree committee member (dgc): Gueguen, Celine, Degree granting institution (dgg): Trent University
Abstract:

A bedrock fracture hosting arsenic (As) contaminated groundwater was suspected to be transported to Ramsey Lake, a drinking water resource for more than 50,000 residents of Sudbury, Ontario. A high resolution, spatial, water quality mapping technique using an underwater towed vehicle (UTV) was used to identify sources of upwelling groundwater into lake water and localize the upwelling As contaminated groundwater vent site. The top 7 cm of lake sediments (in-situ) at this vent site were observed to adsorb 93 % of the dissolved As, thus inhibiting lake water quality degradation from this contaminant source. Sediment samples from this location were used in laboratory experiments to assess the potential for this system to become a source of As contamination to Ramsey Lake water quality and elucidate As(III) fractionation, transformation and redistribution rates and processes during aging. Arsenic speciation is important because As(III) has been shown to be more toxic than As(V). To accomplish this a sequential extraction procedure (SEP) that maintains As(III) and As(V) speciation in (sub)oxic sediments and soils was validated for the operationally defined fractions: easily exchangeable, strongly sorbed, amorphous Fe oxide bound, crystalline Fe oxide bound, and the residual fraction for total As because the characteristics of the reagents required to extract the final fraction do not maintain As species.

Batch reaction experiments using sediment spiked with As(III) or As(V) and aged for up to 32 d were sequentially extracted and analysed for As(III) and As(V). Consecutive reaction models illustrate As(III) is first adsorbed to the sediment then oxidized to As(V). Fractionation analyses show As(III) most rapidly adsorbs to the easily exchangeable fraction where it is oxidized and redistributes to the strongly sorbed and amorphous Fe oxide bound fractions. Oxidation of As(III) adsorbed to the amorphous and crystalline Fe oxide bound fractions is less efficient and possibly inhibited. Select samples amended with goethite provide evidence supporting Mn(II) oxidation is catalyzed by the goethite surface, thus increasing As(III) oxidation by Mn(III/IV) complexed with the strongly sorbed fraction. Although As immobilization through groundwater sediment interactions may be inhibited by increased ion activity, particularly phosphate or lake eutrophication, this threat in Ramsey Lake is likely low.

Author Keywords: arsenic, fractionation, modelling, redistribution, speciation, water quality mapping

2017

Workplace Bullying in Ontario Healthcare Settings: Examining the Relationship Between Bullying, Gender, and Policy

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Creator (cre): Jessup, Sarah, Thesis advisor (ths): Sangster, Joan, Degree committee member (dgc): Hobbs, Margaret, Degree granting institution (dgg): Trent University
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This thesis builds on scholarship that highlights how expected gender roles serve to both normalize and obscure forms of violence and hostility in health care workplaces. An analysis of 25 labour arbitrations involving cases of bullying reveals how gender relations is a factor in these grievances and relevant policies in Ontario health care facilities. Reinforced by underlying expectations around women as nurturing and men as aggressive, responses to bullying are found to reflect and reproduce embedded gendered power inequalities in labour. While bullying in the workplace is often treated in policy discussions as an individual and identity-neutral phenomenon, this research provides evidence to the contrary. As a consequence, we must interrogate existing legislation and policies, asking how we can develop approaches that account for, respond to, and mitigate the causes of bullying rooted in unequal power relations, including gendered ones.

Author Keywords: gender, health care, labour arbitration, policy, workplace bullying, workplace harassment

2017