Electronic Thesis or Dissertation

Due to their effective antibacterial and antifungal properties, silver nanoparticles (AgNPs) have quickly become the most commonly used nanomaterial, with applications in industry, medicine and consumer products. This increased use of AgNPs over the past decade will inevitably result in an elevated release of nanoparticles into the environment, highlighting the importance of assessing the environmental impacts of these nanomaterials on aquatic ecosystems. Although numerous laboratory studies have already reported on the negative effects of AgNPs to freshwater organisms, only a handful of studies have investigated the impacts of environmentally relevant levels of AgNPs on whole communities under natural conditions. This thesis examines the effects of chronic AgNP exposure on natural freshwater littoral microcrustacean, benthic macroinvertebrate and pelagic zooplankton communities. To assess the responses of these communities to AgNPs, I focused on a solely field-based approach, combining a six-week mesocosm study with a three-year whole lake experiment at the IISD – Experimental Lakes Area (Ontario, Canada). Our mesocosm study tested the effects of AgNP concentration (low, medium and high dose), surface coating (citrate- and polyvinylpyrrolidone [PVP]-coated AgNPs), and type of exposure (chronic and pulsed addition) on benthic macroinvertebrates in fine and stony sediments. Relative abundances of metal-tolerant Chironomidae in fine sediments were highest in high dose PVP-AgNP treatments; however, no negative effects of AgNP exposure were seen on biodiversity metrics or overall community structure throughout the study. I observed similar results within the whole lake study that incorporated a long-term addition of low levels of AgNPs to an experimental lake. Mixed-effects models and multivariate methods revealed a decline in all species of the littoral microcrustacean family Chydoridae in the final year of the study within our experimental lake, suggesting that this taxon may be sensitive to AgNP exposure; however, these effects were fairly subtle and were not reflected in the overall composition of littoral communities. No other negative effects of AgNPs were observed on the pelagic zooplankton or benthic macroinvertebrate communities. My results demonstrate that environmentally relevant levels of AgNPs have little impact on natural freshwater microcrustacean and benthic macroinvertebrate communities. Instead, biodiversity metrics and community structure are primarily influenced by seasonal dynamics and nutrient concentrations across both lakes. This thesis highlights the importance of incorporating environmental conditions and the natural variability of communities when examining the potential risks posed by the release of AgNPs into the environment, as simplistic laboratory bioassays may not provide an adequate assessment of the long-term impacts of AgNPs on freshwater systems.

Author Keywords: Benthic macroinvertebrates, IISD - Experimental Lakes Area, Littoral microcrustaceans, Silver nanoparticles, Whole lake experiment, Zooplankton

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

The Kawartha Lakes region of south-central Ontario is dominated by water bodies and rivers, where humans are known to have lived since at least 10,500 years ago, only shortly after the retreat of glaciers from the region. Since this time, water levels within the region have changed dramatically as a result of various geophysical, climatological, and human-induced-phenomenon, leaving modern water levels at a maximum high-stand. While it is acknowledged within the local archaeological community that these hydrological dynamics have resulted in the inundation of much of the region's past terrestrial and culturally active landscapes, cultural research into the region's lakes and waterbodies have to date been very few and limited in scale. The subject of this thesis concerns a cultural assessment of the inundated landscapes around an island within Pigeon Lake of the Kawartha Lakes region, known as Jacob Island. Using a series of integrated methods including bathymetric modeling, shoreline and ecological reconstruction, and in-water-visual artefact survey, the goals of this research relate to illuminating the nature of the Kawartha Lakes region's underwater archaeological record and associating specific cultural occupations and land-use strategies with Jacob island's inundated landscapes.

Author Keywords: inundated landscapes, landscape archaeology, Ontario Archaeology, underwater archaeology

Species ranges are changing and the rate at which the climate is warming is faster than anything previously seen in the past, consequently species will need to adapt quickly, track the climate or perish. Cold adapted terrestrial species are the most vulnerable, because they are limited by the availability of land at the cold edge of their range. This means that many alpine, boreal and polar species essentially have nowhere to go as the climate warms. Habitat generalists are widely distributed across the globe and are highly adaptable to anthropogenic change. Our future biodiversity may only consist of several habitat generalists. The Canada lynx (Lynx canadensis) is a boreal species that has limited range expansion potential at the cold end of its range and its range has already contracted by 40%. The lynx has nowhere to go as climate warming progresses in this current century. Therefore, understanding the causes of its range contraction could enlighten us on conservation and management strategies that we might undertake as climate warms. My analyses indicated that the Canada lynx seems to have tracked the habitat that it is adapted to in more northern homogenous boreal forests and the bobcat (Lynx rufus), a habitat generalist, has simply replaced it in the south.

Author Keywords: Anthropogenic Change, Competition, Connectivity, Lynx canadensis, Lynx rufus, Range change

Temporal lobe epilepsy increases risk for developing major depression, and conversely, depression increases risk for development of epilepsy. The mechanisms responsible for the widely observed bi-directional relationship between epilepsy and depression are currently poorly understood. One reason why our understanding of shared etiology has had little improvement is due to the lack of availability of a reliable animal model for inducing depression in epileptic animals. The development of a reliable model of epilepsy-depression comorbidity would greatly improve the ability to mechanistically evaluate shared pathophysiology between the conditions. Recently there has been evidence that rapid kindling of the basolateral amygdala can evoke a behavioural phenotype that is comparable to the symptoms of anxiety and depression observed in depressed epileptic patients. However, this work has yet to be replicated, leaving question as to whether or not the behavioural phenotype can be reliably evoked. In the following series of experiments we assessed rapid amygdala kindling as a potential model of epilepsy-depression comorbidity and sought to improve the model with inclusion of the glucocorticoid corticosterone. Our findings may improve our understanding of the unique relationships between epilepsy and depression.

Author Keywords: animal models, depression, hippocampus, kindling, stress, temporal lobe epilepsy

Thawing permafrost due to increasingly warm temperatures in northern subarctic regions is releasing mercury. The consequent formation of thaw ponds in the peatland palsa valley of the Sasapimakwananisikw (SAS) river in Whapmagoostui-Kuujjuarapik, Québec may provide a pool for MMHg formation and a potential risk to aquatic and human life, if these ponds facilitate MMHg export through hydrological connections to nearby waterways. Hg methylation and MMHg demethylation activities were examined in thaw pond sediments using a Hg tracer isotope incubation experiment. Analysis by coupling gas chromatography cold-vapor atomic fluorescence spectrophotometry (GC-CVAFS) with inductively coupled mass spectrometry (ICP-MS) techniques showed that MMHg was produced at a higher rate and within the first 2 h of incubation for both summer and winter seasons. For thaw ponds SAS1A, SAS1B and SAS2A, MMHg was formed at 0.0048 % h-1, 0.0012 % h-1, and 0.0008 % h-1, respectively during winter and at 0.0001 % h-1, 0.0016 % h-1, and 0.0010 % h-1, respectively during summer. Detection of MMHg losses were not as expected likely due to limitations of the combined tracer spike and overestimation of the in situ ambient mercury levels. Physical and chemical properties vary within ponds, among ponds and between winter and summer. SAS1B's location nearby an organic carbon rich palsa may be ideal to study DOC – Hg interactions. Variability in pond characteristics including depth, surface area, age, pH, temperature, colour, oxygen concentration, total dissolved and suspended solids, conductivity, carbon, mercury, ammonium, calcium, magnesium, sulfate, total phosphorous, potassium, and sodium between seasons indicate the challenge of predicting future environmental impacts of climate change related thaw pond creation in the north.

Author Keywords: demethylation, mercury, methylation, methylmercury, SAS, thaw ponds

The purpose of this research is to apply four methods on two data sets, a Synthetic

dataset and a Real-World dataset, and compare the results to each other with the

intention of arriving at methods to prevent fraud. Methods used include Logistic Regression,

Isolation Forest, Ensemble Method and Generative Adversarial Networks.

Results show that all four models achieve accuracies between 91% and 99% except

Isolation Forest gave 69% accuracy for the Synthetic dataset.

The four models detect fraud well when built on a training set and tested with

a test set. Logistic Regression achieves good results with less computational eorts.

Isolation Forest achieve lower results accuracies when the data is sparse and not preprocessed

correctly. Ensemble Models achieve the highest accuracy for both datasets.

GAN achieves good results but overts if a big number of epochs was used. Future

work could incorporate other classiers.

Author Keywords: Ensemble Method, GAN, Isolation forest, Logistic Regression, Outliers

This thesis investigated the role of the neuronal ceroid lipofuscinosis protein, Cln5, during autophagy. This was accomplished by performing well-established assays in a Dictyostelium cln5 knockout model (cln5-). In this study, cln5- cells displayed a reduced maximum cell density during growth and impaired cell proliferation in autophagy-stimulating media. cln5- cells had an increased number of autophagic puncta (autophagosomes and lysosomes), suggesting that autophagy is induced when cln5 is absent. cln5- cells displayed increased amounts of ubiquitin-positive proteins but had no change in proteasome protein abundance. During the development of cln5- cells, fruiting bodies developed precociously and cln5- slug size was reduced. Lastly, when cln5- cells were developed on water agar containing ammonium chloride (NH4Cl), a lysosomotropic agent, the formation of multicellular structures was impaired, and the small slug phenotype was exaggerated. In summary, these results indicate that Cln5 plays a role in autophagy in Dictyostelium. The cellular processes that regulate autophagy in Dictyostelium are similar to those that regulate the process in mammalian cells. Thus, this research provides insight into the undefined pathological mechanism of CLN5 disease and could identify cellular pathways for targeted therapeutics.

Author Keywords: Autophagy, Batten disease, Cln5, Dictyostelium discoideum, NCL

Understanding breeding and migration habits of Whimbrel (Numenius phaeopus) in the Hudson Bay Lowlands is important for the conservation of this population. I monitored Whimbrel at two breeding sites: the Churchill region of Manitoba and Burntpoint, Ontario. Annual average nest initiation timing was highly variable and successful nests were initiated significantly earlier than those that failed. Although nests were initiated significantly earlier at Burntpoint than Churchill, annual nest success quantified in program R MARK was similar across sites. Observed nest success rates were lower than historical records and most failure was due to predation. Annual nest survival varied widely and I used a generalized linear model to relate annual nest survival to annual average weather conditions. I observed weak relationships between annual nest survival and weather conditions in the northbound staging grounds. I tracked post-breeding migratory movements using the MOTUS radio telemetry system and observed consistent use of the mid-Atlantic coast of the United States during migration, especially among birds emerging from Churchill. In Burntpoint, I observed more variability in post-breeding migratory trajectories and significantly earlier post-breeding departure as compared to Churchill. The results of my study suggest differences in breeding and migration habits exist across nearby breeding populations, indicating that there is a need for population-specific conservation approaches for this declining species.

Author Keywords: Migration, Movement Ecology, Nesting Ecology, Nest Success, Shorebird conservation, Whimbrel

Many shorebirds rely on small numbers of staging sites during long annual migrations. Numerous species are declining and understanding the importance of staging sites is critical to successful conservation. We surveyed endangered rufa Red Knots staging in James Bay, Ontario during southbound migration from 2009 to 2018. We used an integrated population model to estimate passage population size in 2017 and 2018 and found that up to 27% of the total rufa population staged in James Bay. We also extended the model to incorporate age composition of the passage population. In future applications, this method could improve our understanding of the role of breeding success in population declines. We then estimated annual apparent survival from 2009 to 2018. Survival remained near constant, though lower than estimated elsewhere in the Red Knot range, which may reflect higher permanent emigration rates rather than truly lower survival. This work demonstrates that this northern region is a key staging site for endangered Red Knots and should be included in conservation planning.

Author Keywords: integrated population model, mark-recapture, migratory stopover, shorebirds, species at risk, survival