Exploring the potential of synthetic and natural chelators to enhance phytoextraction by Indian mustard in metal(loid) (As, Cd, Cu, Ni, Pb, Zn and V)-contaminated soils

Soil contamination with metal(loid)s poses significant environmental and human health risks due to their non-biodegradable and highly persistent nature. Phytoextraction is an eco-friendly phytoremediation method that uses plants to extract and accumulate metal(loid)s in harvestable tissues. Chelators can enhance this process by increasing metal(loid) bioavailability through the formation of metal-chelate complexes. Despite the proven effectiveness of synthetic chelators like EDTA, its associated drawbacks, such as excessive metal solubilization, slow degradation rate, phytotoxicity, and the metal leaching risk, have limited its field application. As an alternative, natural chelators such as citric acid (CA) and oxalic acid (OA) offer lower phytotoxicity and greater biodegradability. However, the effectiveness of CA and OA compared to EDTA is poorly investigated under different soil conditions, and a knowledge gap exists in the combined application of these chelators for phytoextraction of acidic multi-metal (loid) contaminated and alkaline V-contaminated soils. Therefore, this thesis examined the effectiveness of chelators alone and in combination for phytoextraction of (i) mining-impacted acidic (pH 5.6) multi-metal (loid) contaminated (As, Cd, Cu, Ni, Pb, Zn) boreal forest soil (first study) and (ii) alkaline soil (pH 7.6) contaminated with V at two different levels (200 and 400 mg/kg V) (second study), using Indian mustard. Separate greenhouse experiments were conducted for 10 weeks (first study) and 13 weeks (second study). Six treatments were applied with triplicates in the first study (control, EDTA, CA, OA at 3 mmol/kg each; EDTA + CA, EDTA + OA at 1.5:3 mmol/kg each) and five (all treatments in study 1 except EDTA) in the second study for each contamination level. Chelators were applied twice at monthly intervals, and soil pore water was collected thrice; before chelator application, after the first application, and after the second application. At the end of the experiment, aboveground biomass (dry weight) and metal(loid) concentrations in pore water, soil, and plant tissues were analyzed using ICP-AES. Results of the first study demonstrated that while EDTA alone or combined with CA and OA was the most effective chelator in increasing the metal(loid) bioavailability in multi-metal(loid)-contaminated soil, it induced severe phytotoxicity in Indian mustard, leading to plant death. Conversely, CA and OA alone had minimal impact on metal(loid) bioavailability and plant uptake but did not induce phytotoxicity. These results suggest that Indian mustard, when used with optimized concentrations of natural chelators alone or in combination with EDTA, could be effective for remediating multi-metal(loid)-contaminated boreal forest soils. In the second study also, EDTA combined applications with CA and OA significantly enhanced the V in pore water, soil, and plant tissues at the 200 mg/kg V-contaminated soils, without inducing phytotoxicity. However, at the 400 mg/kg V-contaminated soils, these treatments were ineffective in increasing V bioavailability and plant uptake. At both V concentrations, natural chelators alone had no significant effect on V phytoextraction. These findings suggest that Indian mustard is suitable for phytoremediation of both acidic multi-metal(loid) (As, Cd, Cu, Ni, Pb, Zn) and alkaline V-contaminated soils. Additionally, the findings highlighted that chelate-assisted phytoextraction is an effective approach to remediate multi-metal(loid) and moderate V-contaminated soils (~ 200 mg/kg). Further investigations are beneficial on optimizing natural chelator concentrations to enhance the phytoextraction efficiency.Master of Science in Bioscience, Technology, and Public Polic

Use of Single and Blended Soil Chemical Amendments to Reduce Phosphorus Loss from Soil

Excessive phosphorus (P) from agricultural soils poses a significant environmental threat due to its contribution to eutrophication in water bodies. Soil amendments have been proposed to reduce soil P solubility and decrease losses in runoff, but their effectiveness, especially as blended amendments, and underlying mechanisms remain underexplored. This thesis investigated the effects of single and blended applications of alum (AlK(SO4)2·12H₂O), ferric chloride (FeCl3), gypsum (CaSO4·2H2O), and magnesium sulphate (MgSO4) on soil P dynamics and transformations in six agricultural soils from Manitoba, and separately examined the effects of single and blended gypsum and ferric chloride in a simplified model soil (artificial soil) system composed of sand, silt, clay, humic acid, and 1000 mg kg⁻¹ total P. In both experiments, soils were incubated for up to 84 days at 22 ±1°C with periodic measurements of water-extractable P (WEP) concentrations and Olsen P concentrations to evaluate potential P loss and available P. Sequential P fractionation was used in both studies after 84 days to identify shifts in P pools. Scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM-EDX) was conducted only in the natural soil study to identify elemental co-localization. In the natural soil study, all amendments significantly reduced WEP concentrations relative to unamended controls except in soil 1. In soil 1, only a few treatments were effective in significantly reduced the WEP concentrations on one or more sampling days. The blended treatments, particularly gypsum or magnesium sulphate combined with ferric chloride, produced the greatest reductions (up to 85%). Decreases in Olsen P were comparatively modest (average of 9.5%), indicating that treatments reduced labile P without substantially lowering agronomically available P. Sequential fractionation revealed that amendments increased recalcitrant P forms and decreased NaHCO3-extracted P and NH4Ac-extracted P. In the controlled model soil experiment, all amendments significantly reduced WEP concentrations compared to the unamended control, with the gypsum + ferric chloride blend showing the most substantial decrease (47.6–58.9%). Olsen P concentrations initially increased in all amended treatments, but by 84 days, only soils amended with ferric chloride or its blend maintained higher Olsen P than the control. Sequential P fractionation revealed a shift from labile to more stable P pools, indicating increased P retention in the soil matrix. Collectively, these findings demonstrate that blended amendments, especially combinations with ferric chloride, enhance P retention by promoting P stabilization in agricultural and model soils.Master of Science in Environmental and Social Chang

Climate envelope models for three endangered skipper butterflies at their northern range margins in Manitoba, Canada

Climate change is accelerating biodiversity loss worldwide, intensifying pressure on already imperiled species. In Canada, several butterfly species are federally listed as endangered due in part to their narrow ranges, small and isolated populations, and dependence on rare or declining habitats, traits that heighten their vulnerability to climate change. Yet, the effects of future climate shifts on their persistence remain poorly understood. This study attempts to model the potential effects of climate change on the future extent of climatically suitable habitat for three at-risk species occurring at their northern range margins in Manitoba, Canada: the Dakota skipper (Hesperia dacotae), Poweshiek skipperling (Oarisma poweshiek), and Mottled duskywing (Erynnis martialis). Endangered species with few occurrences and restricted distributions pose unique modeling challenges, but understanding how climate change may alter their climatically suitable habitat is vital for guiding conservation efforts. To achieve these aims, ensemble climate envelope models (CEMs) were developed using six commonly used algorithms. These models were projected to future conditions using an ensemble of eight high-resolution CMIP6 climate projections for mid- (2041–2070) and late-century (2071–2100) periods, representing two shared socioeconomic pathways (SSP2-4.5 and SSP3-7.0). All ensemble models achieved strong predictive performance based on commonly used evaluation metrics. The Dakota skipper model performed best overall, likely due to more numerous and geographically spread occurrence records. Projections for all species revealed significant declines in climatic suitability across currently occupied areas under all scenarios. Only the Dakota skipper model showed newly suitable regions under future conditions, some within protected areas, offering opportunities for assisted colonisation or targeted habitat assessments. In contrast, no newly suitable areas were identified for the Poweshiek skipperling or Mottled duskywing, likely due to sparse and clustered occurrence data, which limited model generalizability. A key finding is that limited and highly localized species occurrence data can substantially influence model outputs, underscoring the need to interpret CEM results within the context of the quality and quantity of input data. The reliability of ensemble projections depends heavily on input data quality; overlooking this can distort estimates of species’ future suitability even when evaluation metrics indicate strong model performance.Master of Science in Environmental and Social Chang

Haptic Reading: Verse and Prose Inscriptions on Jumping Weights and Discuses

This article examines inscriptions in prose and verse on dedications of athletic equipment from pentathlon competitions, specifically jumping weights and discuses from the Archaic and Early Classical periods. By paying close attention to the layout of inscriptions and contextualizing these sorts of dedications in light of literary evocations of athletic objects, this article argues that handling and moving an athletic dedication added significantly to the meaning and potency of the inscription.https://muse.jhu.edu/article/95469

Plasma microRNA Profiles of Myotis lucifugus from a White-Nose Syndrome-affected Population

White-nose syndrome (WNS), caused by the fungus Pseudogymnoascus destructans (Pd), has devastated bat populations across North America by disrupting torpor, accelerating fat depletion, and causing severe winter mortality. Surviving populations of little brown bats (Myotis lucifugus) exhibit altered fat storage and adaptive physiological responses, suggesting potential mechanisms for WNS resistance or tolerance. MicroRNAs (miRNAs) are small, non-coding RNA molecules regulating gene expression that play critical roles in metabolic and immune pathways essential for hibernation physiology and pathogen defense. My thesis integrates insilico analyses and experimental validation to evaluate the role of miRNAs in hibernation physiology to establish a novel, non-lethal method for monitoring bat health. Using DIANA miRPath and a targeted literature review, I identified four miRNAs (miR-543, miR-27a, miR-92b, and miR-328) implicated in metabolic and immune pathways relevant to WNS, including lipogenesis, insulin signaling, and FOXO-mediated stress response. I quantified the presence and seasonal expression patterns of selected miRNAs using reverse transcription quantitative real-time PCR in plasma samples collected from WNS-affected bats during fall pre-hibernation and spring emergence. miR-27a-5p and miR-92b-5p showed increased expression in spring compared to fall, and miR-27a-5p correlated positively with Pd fungal load, suggesting its potential as a biomarker for WNS severity. miR-26a-5p was consistently stable across seasons and conditions and was used as a robust endogenous control for plasma-based miRNA studies. This study is the first to demonstrate stable detection and seasonal variation of circulating miRNAs in plasma from free-ranging little brown bats, and one of only a handful to quantify plasma miRNA levels in any of the nearly 1500 bat species, establishing a novel, non-lethal method for monitoring bat health. Future studies should validate gene targets and assess how miRNA expression varies with host physiological state and hibernation conditions. Importantly, this approach could guide targeted management interventions by enabling early identification of vulnerable populations or individuals. Ultimately, the ability to monitor bat health non-lethally, using plasma miRNAs, offers significant potential to enhance wildlife disease surveillance, guide conservation strategies, and contribute to the broader effort of mitigating WNS impacts across North America.Natural Sciences and Engineering Research Council (NSERC, Canada) Discovery Grant to Dr. Craig Willis; Research Manitoba MSc Studentship; University of Winnipeg Graduate Studies ScholarshipMaster of Science in Bioscience, Technology, and Public Polic

Researcher Perspectives of Power and Empowerment in Indigenous Community-Based Research

Community-based research (CBR), a methodology which aims to shift power dynamics and empower research participants for social justice ends, has gained significant credibility and popularity in recent decades for research involving Indigenous peoples and communities. However, the concepts of power and empowerment are not well-explained in existing CBR literature, with limited description of what power hierarchies in research are, what it means to challenge them, and what it means to empower participants. This is the first study to explore these concepts in-depth through interviews with researchers. As well as contributing a pragmatic overview of many of the understandings and strategies that researchers use in empowerment-focused CBR projects, this research also questions some assumptions underlying researchers’ perspectives to contribute to ongoing critical discussion. As an exploratory case study, rather than defending a particular hypothesis, this research will serve as a foundation for future investigation into power and empowerment in research.This research was supported by the Social Sciences and Humanities Research Council of Canada, Mitacs, and The University of Winnipeg.Master of Arts in Environmental and Social Chang

The Blameless and Blameworthy: Missing White and Indigenous Women and Girls' Social Construction on Winnipeg Police Service's Facebook Page

Recently, police agencies have harnessed social media platforms, like Facebook, to communicate with the public regarding missing persons cases. I argue that the Winnipeg Police Service (WPS) is mostly absent from the social construction dynamics of missing women and girls. Instead, missing women and girls are socially constructed primarily through the comments and claims of Facebook users who draw on racialized stereotypes to imply these females’ responsibility and blame. Applying Valverde’s (2006) social semiotic template, I analyzed a purposive sample of 20 WPS Facebook posts about missing women and girls from 2019 to 2023 focusing on the selection of images, descriptive text, user comments and reactions. Results revealed that missing Indigenous women were constructed as most blameworthy for their disappearances, while missing Indigenous girls were constructed as less blameworthy, but not without some level of responsibility for their situation. In contrast, missing White women and girls were socially constructed as blameless ideal missing persons worthy of rescue. I conclude by reflecting on the theoretical and methodological implications of my study and offering directions for WPS social media policies to prevent the continued promotion of racial stereotyping and victim blaming.Master of Arts in Criminal JusticeMaster of Arts in Criminal Justic

Bagheri Torbehbar, Arshiya. Summer Roosting and Foraging Habitat of Endangered Little Brown Bats (Myotis lucifugus) in Central Canada

Little brown bats (Myotis lucifugus) are listed as endangered in Canada and by the International Union for the Conservation of Nature (IUCN) due to population declines caused by the fungal disease white-nose syndrome (WNS). Under the Species at Risk Act, conservation efforts must focus on identifying and protecting critical habitats essential for the survival and recovery of listed species. While current efforts for little brown bats emphasize hibernation sites, designating maternity roosts as critical habitats are equally important. Despite some existing data, maternity roosts are not yet designated as critical habitats, but it is crucial as maternity roosts support bats’ recovery from WNS in the spring and successful reproduction and juvenile development in the summer. Understanding both roosting and foraging habitat selection, as well as drivers of foraging behaviour, is important for developing recovery plans, as these habitats are often spatially associated (Balzer et al. 2023). The broad objectives of my thesis are to characterize summer maternity roosts, better quantify roost switching and foraging habitat selection, and better quantify environmental variables that influence bats’ nightly activities. To achieve this, I tagged 30 lactating little brown bats in the summers of 2021 and 2022 (n=15 bats/year) in Ontario, Canada, and tracked them to roosts to identify their roosting habitat selection and quantify roost-switching behaviours. I used data from 2021 (n=15 bats) to understand foraging habitat selection and the influence of factors such as minimum nightly temperatures, maximum wind speed, and air quality on nightly activities and home-range sizes. My Chapter 2 results show that bats predominantly preferred buildings and bat houses over trees, with the largest groups found in buildings, while bats in trees were always solitary. Regardless of roost types, bats preferred structures close to water with southern exposure, possibly to reduce commuting costs to food and drinking areas and to maximize heat gain. These findings should help identify geophysical attributes important for the designation of maternity roosts as critical habitats. Bats in buildings switched roosts significantly less than when they roosted in bat houses or trees, but still switched more than expected, suggesting that management strategies should focus on networks of suitable roosts, rather than individual structures, to meet bats’ roosting requirements. My Chapter 3 results show that bats preferred foraging over wetlands, open water, anthropogenic areas, and forest edges, with bats having larger home-range sizes than observed in comparable studies of this species. Taking advantage of variation in air quality due to wildfire near my study area, I found that bat nightly activities and home-range sizes were significantly affected by air quality, with bats being less active and having smaller home ranges on nights with poor air quality. I found no effect of minimum nightly temperatures or maximum wind speeds on foraging behaviour. These findings underscore the importance of protecting both roosting and foraging habitats to support the recovery of endangered little brown bats.Natural Sciences and Engineering Research Council (Canada); Environment and Climate Change CanadaMaster of Science in Bioscience, Technology, and Public Polic

Signal-to-Noise Ratio and Contrast-to-Noise Ratio Comparisons Between a Wireless Volume Radiofrequency Coil and a Commercially Available Wired Radiofrequency Coil

The design of magnetic resonance imaging (MRI) radiofrequency (RF) coils plays a critical role in determining image quality, with signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) serving as key metrics for evaluation. This study systematically compares the imaging performance of a novel wireless RF coil against a conventional wired coil across three experimental conditions: phantom imaging, fruit imaging, and human brain imaging. Using a phantom, results revealed that the wireless coil exhibited higher SNR, lower CNR, and the images had better quality both in terms of high signal and uniformity. In fruit imaging (watermelon, banana, and pineapple), SNR differences varied by fruit type and imaging protocol, with the wired and wireless coils performing similarly and in more cases, the wireless coil significantly outperforming the wired coil than underperforming. For human brain imaging, the two coils once again performed similarly under most conditions with the wireless coil significantly improving the SNR, particularly in T2-weighted imaging. The wireless coil eliminates bulky structures, reduces costs, and simultaneously produces similar SNR or enhances SNR quality compared to wired coils which provides motivation for our industry partner to continue the development of wireless coils. Future work should further explore the wireless coil’s performance in clinical imaging scenarios, including diffusion-weighted imaging and functional MRI, to better assess its diagnostic potential.Master of Science in Bioscience, Technology and Public Polic

Assessing the Precision of Magnetic Resonance Imaging Axon Diameter Inferences using Oscillating Gradient Spin Echo Pulse Sequences in a 15 T System

Previous research has linked numerous neurological disorders post-mortem to abnormalities in axon distribution and integrity within white matter tracts. Therefore, it is of high interest to investigate methods that will eventually be able to measure axon diameters in white matter tracts in vivo. Diffusion Magnetic Resonance Imaging is a method with the potential to infer microstructure in vivo using temporal diffusion spectroscopy. Temporal diffusion spectroscopy, when used with certain pulse sequences, such as Oscillating Gradient Spin Echo, can be used to infer micron-scale axon diameters. The most common geometric model used to fit the diffusion signals assumes that axons are long, parallel, straight, cylinders, where only the transverse intra-axonal diffusion coefficient is sensitive to the cylinder’s inner diameter. However, previous research has demonstrated that this geometric model tends to overestimate the intra-axonal diameter of axonal fibers. Due to recent advances in hardware, high-gradient strengths can be used to achieve shorter diffusion times and probe smaller restriction sizes than previously possible. To calibrate temporal diffusion spectroscopy with Oscillating Gradient Spin Echo pulse sequences in this project ex vivo mouse brains were imaged, and the genu substructure of the corpus callosum was analyzed. The images were collected using a 15.2 T Bruker NMR system located at the Vanderbilt University of Institute of Imaging Science. Data were collected in two experiments; first an initial calibration experiment was performed to test the proposed parameters. Then a second experiment was conducted to validate the inferred magnetic resonance axon diameters using transmission electron microscopy in a sample of 6 mice (3 male, 3 female)."I would like to acknowledge the financial support provided by the Natural Sciences and Engineering Research Council of Canada (NSERC) and Research Manitoba."Master of Science in Bioscience, Technology and Public Polic