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Get PDFCanada First Research Excellence FundNon-Peer ReviewedOutline of Global Water Futures program work carried out by Knowledge Mobilization, Communcations, and program management teams to capture stories of research engagement
More than Cold Dirt : Discovering the human face of climate change research in northern Canada
Get PDFCanada First Research Excellence FundNon-Peer ReviewedPersonal account of a researcher's experience learning from local people while investigating groundwater contamination related to thawing permafrost in Canada's Yukon Territory
GRASSLAND BIOPHYSICAL PARAMETERS ESTIMATION USING REMOTE SENSING PRODUCTS TO SUPPORT PASTURE INSURANCE
No full textAs a source of food and employment, livestock farming is an important activity for many societies around the world. In a global context, livestock farming has significant differences due to cultural and environmental aspects. A common goal of livestock producers is for the herd to gain weight and to do so it is necessary to have food available for the animals throughout the year. Unfortunately, pasture growth is susceptible to risks such as overgrazing and climate variation, which makes productivity highly variable over time, affecting ecosystem sustainability and bringing economic losses to producers. To mitigate economic losses, one of the alternatives for producers is to resort to agricultural insurance programs. Within the agricultural insurance market, the index-based approach, which considers remotely obtained variables such as precipitation data and vegetation indices, has gained notoriety for having greater geographical coverage, lower operating costs, and faster premium payments. In this context, the main objective of this research is to investigate and identify inputs that can increase the accuracy of remote monitoring of pastures. The inputs/products derived from remote sensing addressed in this research can contribute to characterizing the canopy of a given area of interest, validate gridded precipitation data that can replace weather stations, and estimate biomass production. The results of this research show that remote sensing is effective for estimating biophysical parameters of native grasslands and identifying differences between vegetation conditions in different ecoregions of the Canadian Prairies. Despite having identified indices such as the normalized difference vegetation index (NDVI) and the normalized difference moisture index (NDMI) as indicators of vegetative growth, and the plant senescence reflectance index (PSRI) as an indicator of senescence, the leaf area index (LAI) proved to be an interesting parameter to be used for monitoring native grasslands because it presented significant correlation with other biophysical parameters. Good results were obtained for differentiating grassland/forage types at a more detailed level, especially in the Moist-Mixed and in the Mixed Ecoregions. Evidence was also gathered that gridded data can be important to estimate precipitation and identify atmospheric events that may affect plant development, especially in regions with few meteorological stations or with gaps in the time series. It was concluded that the dry matter productivity model (DMP), despite the short data history, is a better biomass production estimator than the NDVI and the enhanced vegetation index (EVI2), especially when combined with other parameters such as annual average NDVI and the annual average temperature. The results obtained in this research showed solid evidence that remote sensing can improve the accuracy of pasture monitoring and be a valuable support tool for the agricultural insurance market, especially for the index-based approach, making the relationship between insurance companies and rural producers clearer and fairer
The Chapel Island Formation of Newfoundland (Canada) revisited: integrating ichnologic and sedimentologic datasets to unravel early metazoan evolution
Get PDFThe Chapel Island Formation (CIF) is a 1000+ m-thick, mainly siliciclastic succession that is well exposed along the coastline of Burin Peninsula, southeastern Newfoundland, eastern Canada. The CIF contains an outstanding record of latest Ediacaran-early Cambrian trace fossils with some intervals rich in small shelly fossils, and in 1992 the Fortune Head section was ratified by the International Commission on Stratigraphy (ICS) and the International Union of Geological Sciences (IUGS) as the Global Stratotype Section and Point (GSSP) for the Cambrian System. This was the first system-level GSSP defined primarily on the basis of trace fossils, a decision that evoked considerable discussion among the geological community. This thesis represents the first modern study of the sedimentology and the first taxonomic appraisal of the trace fossils since the original studies that proposed the GSSP in the 1980’s. More than 1700 m of CIF strata were logged in the sea cliffs of Burin Peninsula at Fortune Head, Fortune North, Grand Bank Head, Lewin’s Cove, Little Dantzic Cove, and Point May. A revision of the sedimentology permitted the description and interpretation of fourteen sedimentary facies composing five facies association (FA), which are interpreted to be deposited in: (1) mud-flat, mixed-flat, sand-flat, and tide-dominated or -influenced embayments (FA-A); (2) middle and lower shoreface (FA-B); (3) offshore transition, upper offshore, and lower offshore (FA-C); (4) shelf (stricto sensu) (FA-D); and (5) carbonate subtidal and intertidal environments (FA-E). An extensive trace-fossil dataset was built from careful field observations and provided a comprehensive record of bioturbation intensity (1596 data points on vertical bioturbation, 1481 data points on bedding plane bioturbation) and of trace-fossil metrics (3162 data points on burrow width, 1473 data points on burrow depth). In addition, a comprehensive revision of the trace-fossil composition (3508 trace fossils identified) allowed the description of twenty-eight ichnogenera and fifty-one ichnospecies, which correspond to cf. Allocotichnus dyeri, Archaeonassa fossulata, Arenicolites aff. carbonaria, Arenicolites isp., Bergaueria perata, B. cf. radiata, Circulichnis ligusticus, C. montanus, Cochlichnus anguineus, C. luguanensis, Conichnus conicus, Cruziana problematica, Curvolithus multiplex, C. simplex, Curvolithus isp., Dendroidichnites aff. irregulare, Didymaulichnus miettensis, Dimorphichnus isp. A, Dimorphichnus isp. B, cf. Dimorphichnus isp., ?Diplocraterion isp., Gordia marina, Gyrolithes gyratus, G. scintillus, Halopoa imbricata, Helminthoidichnites tenuis, Helminthopsis abeli, H. hieroglyphica, H. tenuis, Monomorphichnus bilinearis, M. lineatus, M. needleiunm, Monomorphichnus isp., Palaeophycus annulatus, P. tubularis, Palaeophycus isp., Psammichnites gigas circularis, P. cf. saltensis, Rosselia socialis, Rusophycus avalonensis, Rusophycus isp. A, Rusophycus isp. B, Saerichnites kutscheri comb. nov., Teichichnus rectus, Torrowangea rosei, Treptichnus bifurcus, T. coronatum, T. pedum, T. pollardi, Trichichnus linearis, and Trichichnus isp. Sectioning and polishing of 47 lithic samples from throughout the CIF showed that the sediment mixed layer that characterizes modern oceans developed through a series of steps that took place in the early Cambrian rather than in the Silurian as previously advocated. The main evolutionary innovations took place in the offshore environment with three paleoecologic stages that comprised: (1) an Ediacaran matground ecology, with surficial and very shallow infaunal grazing organisms living on and within microbially bound seafloors; (2) a Fortunian matground/firmground ecology, with a burst in behavioural and anatomical innovations and the first evidence of colonization of the shallow-tier; and (3) a late Fortunian/Cambrian Age 2 mixground ecology, with the development of a shallow mixed layer and deeper discrete burrows of the transition layer. Evaluation of outcrop quality based on accessibility, lateral and vertical continuity of beds, stratigraphic completeness, and type of exposure, demonstrated that Fortune Head, Fortune North, Grand Bank Head, and Little Dantzic Cove represented the best suited section to perform trace-fossil analyses, whereas Lewin’s Cove and Point May suffered from exposure biases affecting their trace-fossil records. The Ediacaran-Cambrian boundary interval was also studied in detail at Fortune Head, Grand Bank Head, Lewin’s Cove, and Point May, and the base of the Cambrian was placed confidently at the first appearance of trace fossils of the Treptichnus pedum Ichno-Assemblage Zone. This study demonstrates that only through detailed, comprehensive, and integrative approaches, can research provide new empirical evidence that further unfold our understanding of the history of animal life on Earth
Bias-Corrected RADARSAT-2 Soil Moisture Dynamics Reveal Discharge Hysteresis at An Agricultural Watershed
No full text© 2023 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https:// creativecommons.org/licenses/by/ 4.0/).Global Water Futures program at the University of Saskatchewan (419204-1323-8000-23476 Integrated Modelling Program for Canada)Peer ReviewedSatellites are designed to monitor geospatial data over large areas at a catchment scale. However, most of satellite validation works are conducted at local point scales with a lack of spatial representativeness. Although upscaling them with a spatial average of several point data collected in the field, it is almost impossible to reorganize backscattering responses at pixel scales. Considering the influence of soil storage on watershed streamflow, we thus suggested watershed-scale hydrological validation. In addition, to overcome the limitations of backscattering models that are widely used for C-band Synthetic Aperture Radar (SAR) soil moisture but applied to bare soils only, in this study, RADARSAT-2 soil moisture was stochastically retrieved to correct vegetation effects arising from agricultural lands. Roughness-corrected soil moisture retrievals were assessed at various spatial scales over the Brightwater Creek basin (land cover: crop lands, gross drainage area: 1540 km2) in Saskatchewan, Canada. At the point scale, local station data showed that the Root Mean Square Errors (RMSEs), Unbiased RMSEs (ubRMSEs) and biases of Radarsat-2 were 0.06~0.09 m3/m3, 0.04~0.08 m3/m3 and 0.01~0.05 m3/m3, respectively, while 1 km Soil Moisture Active Passive (SMAP) showed underestimation at RMSEs of 0.1~0.22 m3/m3 and biases of 0.036~0.2080 m3/m3. Although SMAP soil moisture better distinguished the contributing area at the catchment scale, Radarsat-2 soil moisture showed a better discharge hysteresis. A reliable estimation of the soil storage dynamics is more important for discharge forecasting than a static classification of contributing and noncontributing areas
Effect of sub-inhibitory antibiotic exposure on antimicrobial resistance of river biofilm microbial communities
No full textBiofilms are ubiquitous throughout aquatic environments and can be influenced by myriad
factors including antimicrobial run-off from anthropogenic sources. The South Saskatchewan
River is an oligotrophic system that receives discharge from urban wastewater treatment plants
(WWTP) and agricultural effluents which can carry antimicrobial residues. Antibiotic
concentrations in environmental systems generally occur at low or sub-minimum inhibitory
concentrations (sub-MICs). Most of our current understanding of antibiotic resistance comes from
clinically relevant monoculture studies. Thus, there is a need for experimental data that explores
the response of naturally occurring multispecies microbial communities.
This thesis employs a “structure-function” approach by using microscopic and metagenomic
methods to characterize the effects of sub-MIC antibiotics in riverine biofilm communities. I aimed
to determine whether exposure induced a selective pressure for antibiotic resistance resulting in
variations of overall community composition. For this purpose, riverine biofilm communities were
developed in a microcosm system under various sub-MIC exposure treatments including constant
sub-MIC exposure (1/10, 1/50 and 1/100 MIC) to a mix of common antibiotics (ciprofloxacin,
streptomycin, and oxytetracycline), and residual antibiotic concentrations present in WWTP
effluent and swine-manure (SM). This research was divided into two microcosm experiments: a
pilot experiment and a full-scale experiment. Microscopic methods were used to characterize the
structural composition of biofilms, and different metagenomic tools were evaluated and compared
seeking to elucidate comprehensive microbiome and resistome profiles in biofilm communities.
Results of this thesis research demonstrated shifts in biofilm architecture, microbiome and
resistome composition. Biofilm formation and accumulation of extracellular polymeric substances
(EPS) were inversely proportional to the concentration of antibiotics. Microbial diversity wasiv
reduced after sub-MIC antibiotic exposure, selecting for Pseudomonadota (synonym
Proteobacteria) species, particularly at the sub-MIC 1/10 condition. The biofilm resistome
consisted of antibiotic resistance genes (ARGs) that conferred resistance to aminoglycosides,
tetracyclines, β-lactams, macrolides, phenicols and sulfonamides and trimethoprim. Resistome
relative abundance and diversity was consistently higher in biofilms grown under sub-MIC
antibiotic exposure. Nonetheless, ARGs and virulence genes were observed across all samples
including biofilms grown under non-antibiotic conditions. Correlation between the microbiome
and resistome showed that aminoglycoside ARGs were associated with several bacterial genera,
and co-occurrence between virulence factors and ARGs was also significant.
Functional prediction analysis indicated that abundance of metabolic pathways involved in
cell-wall metabolism increased under the presence of sub-MIC antibiotics, thus supporting the
notion that low concentrations of antimicrobials exert selective pressure. Overall, results from our
whole-community approach demonstrated that the presence of sub-MICs antibiotics increased the
abundance of ARGs and resistome-related functions. These responses indicate that riverine biofilm
communities promote the prevalence and facilitate the transmission of antimicrobial resistance
Motivations and Narratives of Canadian Immigrant Influencers
Get PDFThis research study uncovers the phenomena of social media influence within the Canadian legal immigration context. Aligning with an interpretative phenomenological approach, twenty-one personal semi-structured in-depth interviews were conducted with Canada-based Latin American social media influencers (SMIs) to access their lived experiences and perspectives. This study revealed how the immigration landscape and acculturation process encouraged Latino immigrants to undertake a role as opinion leaders and follow a professional journey in which the level of expertise defines the types of motivations and goals that drive them to perform this social media practice within the immigration approach. The findings present evidence of an intangible consumption context that is being digitally promoted as a lifestyle value proposition collectively co-created and communicated before, during, and after the immigration consumption process. Furthermore, this research explains how SMI’s content is structured with stories about their own experiences and cultural resources which are also developed as localized and customized narratives. Theoretical implications associated with the findings are offered, as well as future research, and managerial and public policy connotations
Biological Activity, Analytical Detection, and Degradation Assessment of the S-epimers of Ergot Alkaloids
Get PDFErgotism has an extensive history dating back centuries. The fungus Claviceps purpurea produces ergot sclerotia that contain secondary metabolites called ergot alkaloids. Ergot alkaloids cause toxic effects after consumption of ergot contaminated food and feed. Ergot contaminated food and feed currently poses a health risk to humans and animals. There are six common ergot alkaloids produced by the fungus that exist in two configurations. The two configurations are the C-8-R-isomer (R-epimer) and the C-8-S-isomer (S-epimer), the latter of which has been studied to a lesser extent. The S-epimers have been considered inactive in terms of biological activity compared to the R-epimers. The R-epimers can elicit their toxic effects by binding to receptors in vascular smooth muscle cells. In this dissertation, the aim was to further understand the S-epimers of the six ergot alkaloids common to Claviceps purpurea through biological, analytical, and degradation assessments. An arterial tissue bath technique was used to assess the bioactivity of selected S-epimers. Following the exposure of arteries to the S-epimers, vascular constriction was observed. Exposure of increasing concentrations of the S-epimers to the arteries resulted in an increase in the contractile response. In a following study, arterial contraction due to the S-epimers over time was assessed and a sustained vascular contraction was observed. The sustained vascular contraction of the S-epimer was different than the corresponding R-epimer, which may be due to differences in vascular contraction mechanisms. This is the first time that the S-epimers of ergot alkaloids have demonstrated bioactivity, contrary to historical belief. To support the vasoconstriction observed in the previous studies, a novel approach using an in silico method to assess ergot structure activity relationships was used, specifically to observe the S-epimer-vascular receptor relationship. The S-epimers bound to vascular receptors with relatively high affinity and strong molecular interactions, which has not been documented previously. Since the S-epimers demonstrated bioactivity and can bind to vascular receptors, it was important to assess the concentrations of the S-epimers in natural ergot contaminated samples. A newly validated analytical method to detect and quantify R and S-epimer concentrations using high-performance liquid chromatography tandem mass spectrometry (HPLC-MS/MS) was used. This new analytical method can be implemented in laboratories worldwide for the sensitive and accurate detection and quantification of ergot epimers. It was observed that the S-epimers of the six common ergot alkaloids constitute approximately 35% of the total ergot alkaloid concentration in the samples assessed. When the natural ergot contaminated samples were exposed to various temperatures over time, the R and S-epimer concentrations varied. Therefore, ergot contaminated samples should be analyzed prior to their use for food or feed to obtain the most accurate concentration results. The high concentration of the S-epimers and the lack of concentration stability warranted an investigation into the degradation of the S-epimers associated with their potential bioactivity which can lead to toxic effects. Some studies assessing degradation methods of ergot alkaloids only quantify or focus on the R-epimers and not the S-epimers. Through using degradation methods of ammonia and ultra-violet (UV) light, based on practicality, we observed that the R and S-epimer concentrations behave differently, following the degradation methods. Ammonia significantly reduced the concentration of total ergot alkaloids, while demonstrated varied effects on the concentrations of the R and S-epimers. The use of ammonia for the degradation of ergot alkaloids may be a practical means for livestock to consume ergot contaminated feed without any adverse effects. The use of UV light did not significantly alter the concentrations of the total ergot alkaloids; however, it decreased the concentration of the S-epimer, ergotaminine. Since the effects of the degradation methods on the R and S-epimer concentrations may vary, it is important to assess both configurations following degradation assessments. Overall, this research has furthered our understanding of the S-epimers of ergot alkaloids. Continuous research on the S-epimers of ergot alkaloids is needed to further understand the S-epimers in terms of their bioactivity, stability, and degradation. It was important to investigate the S-epimers since they were historically deemed as non-bioactive and have not been thoroughly researched, compared to the R-epimers. The results of this dissertation have demonstrated, for the first time, the bioactivity of the S-epimers and the use of a novel in silico method to assess how the S-epimers may contribute to the adverse effects associated with ergot alkaloids. In addition, high concentrations of S-epimers were observed within ergot contaminated samples and the use of ammonia as a method to degrade ergot epimers may be practical within the agriculture industry. Guidelines for the concentrations of ergot alkaloids in food and feed have been set worldwide; however, some guidelines only include the R-epimers and not the S-epimers. The results of this dissertation encourage the inclusion of the S-epimers into guidelines globally for both food and feed for the protection of human and animal health. The observation that the S-epimers are bioactive, have high concentrations in contaminated matrices, and may contribute to the toxic effects following ergot alkaloid consumption, will ultimately improve food and feed safety guidelines for both human and livestock populations
EFFECT OF CATALYST SUPPORT ON THE PERFORMANCE OF α-MNO2 IN CATALYTIC OZONATION OF VOCS
Get PDFThis thesis aims to give a new insight into the selection of supports from two groups (inert and semiconductor) for α-MnO2 in VOC oxidation in catalytic ozonation of VOCs. The study focuses on two types of VOCs, toluene and acetone, representing nonpolar and polar compounds, respectively, at room temperature. Four supports were evaluated, including two semiconductors (TiO2, SiO2) and two inert materials (Al2O3, zeolite (ZSM-5- 20% SiO2 and 80% Al2O3)), chosen for their commercial availability, environmentally friendly nature, and widespread industrial use.
The study found that TiO2 as a support material exhibited the highest performance in the removal of both polar (acetone (around 95.5%)) and nonpolar (toluene (around 98%)) VOCs. This finding is particularly significant given that TiO2 has a lower surface area compared to zeolite and Al2O3. Furthermore, the study revealed that TiO2 as a support material led to the formation of lower oxidation states in MnO2, enhancing the catalytic activity of α-MnO2 for VOC removal. Additionally, TiO2 exhibited a higher oxygen vacancy, further enhancing the catalytic activity of α-MnO2. The effect of environmental factors (humidity and temperature) was also evaluated and proved that supports could enhance the stability and performance of catalysts in the presence of humidity. α-MnO2/TiO2 showed high stability and experienced minimum reduction in activity over time in the presence of humidity. Overall, this study demonstrates the potential of TiO2 as a promising support material (semiconductor) for efficient removal of VOCs at room temperature, with particular advantage in removing nonpolar VOCs such as toluene