Graduate Theses & Dissertations

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Proximal Soil Nutrient Sensing in Croplands through Multispectral Imaging from Unmanned Aerial Vehicles (UAV) for Precision Agriculture Applications
Currently, UAVs are deployed to measure crop health in a timely manner by mapping vegetation indices. A study using two different fields was conducted in order to search for a relationship that may exist between crop health and soil fertility. A UAV equipped with sensor technology was used for mapping of vegetation indices which were then statistically compared to soil nutrient data collected via soil sampling. Elevation data was also collected which was then statistically compared to soil nutrients as well as crop health. Results of this study were unfortunately impacted by variables outside of the researcher’s control. Moisture became the greatest limiting factor in 2016 followed by an excess of rain in 2017. Results did not show any promising correlations as moisture uncontrollably became the defining variable. Further research in a more controlled setting will need to be conducted in order to explore this potential relationship. Author Keywords: Agriculture, Multispectral Imagery, Precision Agriculture, Proximal Soil Sensing, Remote Sensing, Unmanned Aerial Vehicle
Interpretation of forest harvest recovery using field-based and spectral metrics in a Landsat time series in Northwestern Ontario
The forestry sector has a well-developed history of using remote sensing to identify structural characteristics of forests and to detect and attribute changes that occur in forested landscapes. Monitoring the recovery of disturbed forests is an important factor in long term forest management. However, forest that is recovered spectrally may not be recovered when considered in terms of a Free to Grow assessment. A Free to Grow assessment is used in Ontario to determine whether a disturbed site will likely achieve a desired future state, i.e., is recovered according to a forestry perspective. The objective of this research was to determine the relationship between a pixel-based Landsat Time Series of spectral recovery and the results of Free to Grow assessments. Spectral trajectories were generated from representative pixels within known harvested forest areas. Results indicate that while Free to Grow sites often achieve spectral recovery (>90%), many non-Free to Grow sites were classified as spectrally recovered, suggesting that improved methods of spectral recovery monitoring are needed. Author Keywords: forest recovery, Free to Grow, Landsat Time Series, LandTrendr, Pixel-based, spectral recovery
Influence of Nitrogen Deposition on Community Composition in Pinus banksiana Forests Across Northwestern Canada
Anthropogenic atmospheric emissions and subsequent deposition of nitrogen (N) can affect N-sensitive habitats and lead to shifts in plant species community composition. This study assessed the effects of N deposition on plant community composition for Jack pine forests across northwestern Canada and across a smaller subset of sites surrounding the Athabasca Oil Sands Region (AOSR) using ‘gradient forest’ analysis. Predictor influence on community composition varied depending on the scale of the study and relatively distinct thresholds were identified for different plant groups. In the larger scale study, a total deposited nitrogen (TDN) threshold of 1.5 – 3 kg N ha-1yr-1 was well suited to protect predominantly lichen species, consistent with lichen-based critical loads from other studies. Across the smaller scale study, a TDN threshold of 5.6 kg N ha-1yr-1 was primarily associated with vascular species changepoints but did include some important N-indicator lichen and bryophyte species. Author Keywords: critical loads, gradientForest, Jack pine, Nitrogen deposition, species composition
Daphnia pulicaria responses to temperature and nutrients stress
Warming climates have had various consequences on terrestrial and aquatic food webs that are expected to persist. There is evidence suggesting that certain organisms are better equipped to handle changing climates compared to others. Therefore, the purpose of my thesis was to study the adaptability of Daphnia under temperature stress and nutrient limitation. First, to examine the effects of dietary phosphorus limitation and temperature on daphniid life-history and population growth, a series of experiments were conducted in the laboratory. In general, I found that Daphnia body growth rates and life-history traits to food carbon to phosphorus (C:P) ratios change with temperature. Next, I identified a protocol to limit the genomic DNA (gDNA) from ribonucleic acid (RNA) extractions. I found that using a modified phenol-chloroform extraction protocol was the most effective way to remove gDNA from extracted Daphnia RNA samples. Overall, results from this study show that temperature and food quality interactions are more complicated than previously thought. Furthermore, the RNA extraction protocol developed will be useful in future studies examining gene expression responses in Daphnia. Author Keywords: ecological stoichiometry, gene expression, life-history, nutrient limitation, RNA puritiy, temperature
Temporal variation of dissolved organic matter and diffusive gradient in thin films-labile mercury in the Quesnel river, BC, and the Goose Creek tributary of Churchill river, MB
This study examined dissolved organic matter (DOM) and labile Mercury (from diffusive gradient in thin films (DGT)) in the Quesnel river, British and the Goose creek tributary of the Churchill river, Manitoba. DOM properties were measured with optical measurements of absorption coefficient (a254), spectral slopes (S275-295, SR) and fluorescence indices (HIX, BIX, FI). The DOC proxy measurements (a254) were almost 10 times higher at the Churchill site (Mean a254 116.77 cm-1) compared with the Quesnel river site (Mean a254 12.06 cm-1) during the study periods. While DGT labile Hg concentrations at the Quesnel site (2.17 to 98.97ppt) were almost 10 times more than the levels reported at the Churchill site (0.03 to 9.06 ppt). Fluorescence indices and the rise of labile Hg concentrations in spring indicated mostly terrestrial sources of DOM at both the sites. Spectral slopes and fluorescence indices substantiated that Churchill site had high molecular weight, complex and more humic DOM compared with Quesnel. DOM at both the sites was prone to temporal variation and affected by environmental conditions. Correlation between DGT labile-Hg and DOM parameters suggested that DGT collected Hg-organic complexes along with inorganic labile-Hg complexes. Author Keywords: Churchill, Diffusive gradient in thin films, Dissolved organic matter, Labile Hg, Mercury, Quesnel
Solving Differential and Integro-Differential Boundary Value Problems using a Numerical Sinc-Collocation Method Based on Derivative Interpolation
In this thesis, a new sinc-collocation method based upon derivative interpolation is developed for solving linear and nonlinear boundary value problems involving differential as well as integro-differential equations. The sinc-collocation method is chosen for its ease of implementation, exponential convergence of error, and ability to handle to singularities in the BVP. We present a unique method of treating boundary conditions and introduce the concept of the stretch factor into the conformal mappings of domains. The result is a method that achieves great accuracy while reducing computational cost. In most cases, the results from the method greatly exceed the published results of comparable methods in both accuracy and efficiency. The method is tested on the Blasius problem, the Lane-Emden problem and generalised to cover Fredholm-Volterra integro-differential problems. The results show that the sinc-collocation method with derivative interpolation is a viable and preferable method for solving nonlinear BVPs. Author Keywords: Blasius, Boundary Value Problem, Exponential convergence, Integro-differential, Nonlinear, Sinc
Assessing limnological characteristics of subarctic Québec thaw ponds and mercury methylation and methylmercury demethylation within their sediments
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
Predictive Digital Mapping of Soils in Kitimat, British Columbia
Soil is an essential natural resource that supports provisioning services such as agriculture, silviculture, and mining. However, there is limited knowledge on forest soil properties across Canada. Digital soil mapping may be used to fill these data gaps, as it can predict soil properties in areas with limited observations. The focus of this study was to develop predictive maps of select soil physicochemical properties for the Kitimat Valley, British Columbia, and apply these maps to assess the potential impacts of sulphur dioxide emissions from an aluminum smelter, on soil properties in the Valley. Exchangeable [Ex.] magnesium, organic matter, pH, coarse fragment, Ex. potassium, bulk density, Ex. calcium, Ex. acidity, and Ex. sodium were all mapped with acceptable confidence. Time to depletion of base cation pools showed that ~240 km2 of the study area had a depletion time of 50 years or less. However, sources of base cations such as atmospheric deposition and mineral weathering were not considered. Author Keywords: acidification, buffering capacity, Digital soil mapping, predictive mapping, regression kriging, soil properties
Fraud Detection in Financial Businesses Using Data Mining Approaches
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
Breeding Phenology and Migration Habits of Whimbrel (Numenius phaeopus) in the Hudson Bay Lowlands, Canada
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
Passage population size, demography, and timing of migration of Red Knots (Calidris canutus rufa) staging in southwestern James Bay
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
Effects of Recycled Media on Culture Growth and Hormone Profiles in Heterotrophic Euglena gracilis
The rapid expansion of the worldwide population has caused an urgent need for the development of new, more environment-conscious, food sources. In this context, algae, such as Euglena, are of interest thanks to their capacity to naturally produce essential nutrients such as proteins and oils commonly found in animals and plant sources. While these processes are currently being investigated, underlying measures affecting growth of Euglena gracilis like hormonal influences and growth stress like nutrient deprivation are poorly understood. From this vantage point, this thesis seeks to understand the role of phytohormones cytokinin (CKs) and abscisic acid (ABA) in complex mechanisms underlying heterotrophic growth of Euglena gracilis under recycled, organic media conditions with no supplementation. Hormone profiles were quantified by HPLC-ESI-MS/MS and compared to culture growth dynamics of pH, weight accumulation, glucose content, cell count and morphology. It was expected that ABA acted as an inhibitory hormone and this was confirmed by its higher levels when CKs where low and vice versa. Contrastingly, it was expected that CKs stimulated growth, in which this was shown not to be the case. Interestingly, it was revealed that both hormone groups increase with increasing recycling. Other key findings include: E. gracilis synthesizes CKs via the tRNA-degradation pathway and is cZ and iP dominated, recycling E. gracilis medium is viable for growth, however, the percentage (25% or less) is crucial to cell viability and markedly no ABA was detected in E. gracilis pellet fractions from recycled media. Therefore, this data revealed that recycled media has a striking influence on physiological aspects of growth and illustrated unique changes in hormone profiles of which could be manipulated to help the food industry. Author Keywords: cytokinin, endogenous hormones, Euglena gracilis, heterotrophic, large scale microalgae cultivation, recycled medium

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