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Coastal ecology of Atlantic Tomcod Microgadus tomcod (Walbaum, 1792) in Minas Basin, Nova Scotia: spawning migration, habitat connectivity, and diet
No full textAtlantic Tomcod (Microgadus tomcod) is a gadid fish that lives for an average of three years and occurs along North Atlantic coastlines from Labrador, Canada to Virginia, USA. It is abundant in coastal waters in Nova Scotia and is a valuable food resource for many predators. It is also known as “frostfish” given that it spawns further inshore during the winter months in estuaries and freshwater streams. It has been fished as a minor commercial and recreational species and has traditionally been used as a winter food source by Mi’kmaw First Nations communities throughout its range. Tomcod is known as “punamu” in the Mi’kmaq language. Despite its abundance and local relevance, there has been little research on its ecology and movement. This study, which was a part of a collaborative project entitled Apoqnmatulti’k, used acoustic telemetry to investigate seasonal spawning migrations of 186 tagged tomcod from November – February from adjacent tidal river systems in Minas Basin to potential spawning areas. Findings identified regions of importance to tomcod, as well as patterns of connectivity between areas across the basin. Tomcod were found to exhibit long-range movement to and from Minas Passage, despite being documented as a coastal species with limited home ranges. There were also high rates of inshore activity, which coincided temporally with the reproductive period of tomcod that often takes place in mouths of rivers. This study also incorporated biological sampling, including morphological identification of consumed prey, to determine baseline tomcod dietary preferences and feeding habits in Minas Basin. Tomcod consumed predominantly Corophium amphipods, as well as Crangon shrimp and Gammarus amphipods, and a variety of other taxa. The diversity of prey consumed indicates that tomcod feed opportunistically, likely in proportion to the abundance of the taxa as they are found in the Bay of Fundy. Gonadosomatic index increased significantly over time, which indicates that Atlantic Tomcod were preparing for their winter spawning during the months of October through December. Results of this research will be used to inform management approaches and strategies for Atlantic Tomcod in local regions to enable better stewardship of this resource.</p
Excited state intramolecular proton transfer (ESIPT) efficiency enhancement in phenols due to o-alkyl groups
No full textWidely distributed in nature, phenols are a class of chemical compounds that consist of a hydroxyl group bonded directly to a carbon atom in an aromatic ring. Phenols are weak acids with pKa values around 10, but they become dramatically more acidic after they absorb light and enter their singlet excited state. The increased acidity of excited phenols can result in a reaction called Excited State Intramolecular Proton Transfer (ESIPT), in which an acidic hydrogen atom is transferred to a basic site on the same molecule. Fundamental to the function of human sunscreens, as well as the natural mechanisms used by plants and animals to protect themselves from the damaging effects of UV light, this process is biologically important.Four phenols were prepared with alkyl groups increasing in size at the ortho-position of the phenol OH via bromination, methylation, Suzuki coupling, and demethylation: 6-methyl-2-phenylphenol (22), 6-ethyl-2-phenylphenol (23), 6-isopropyl-2-phenylphenol (24), and 6-tert-butyl-2-phenylphenol (25). All four compounds were characterized using 1H nuclear magnetic resonance (NMR) spectroscopy and investigated using product studies, fluorescence spectroscopy, and mass spectrometry (MS). To determine ESIPT quantum yields, MS was used to track deuterium incorporation. The widely studied 2-phenylphenol (8) which only has a hydrogen at the 6-position was used as a reference standard.Compounds 22-25 successfully underwent ESIPT at the 2’-position followed by reverse proton transfer (RPT) to return to starting material. Quantum yields for 22-25 were 0.20, 0.24, 0.26, and 0.30, respectively, which suggested that the ESIPT reaction became increasingly efficient as the alkyl group added to the 6-position became larger. The addition of the tert-butyl group improved the ESIPT reaction efficiency the most dramatically, by nearly quadrupling the quantum yield of ESIPT compared to 8 from the literature (Φ = 0.082). Fluorescence measurements were also carried out to support the proposed mechanism. These results are consistent with the hypothesis that increasing the size of R groups added at the 6-position can increase ESIPT efficiency by forcing the molecule into a conformation that is ideal for ESIPT, where the phenol OH is pointed toward the phenyl ring.</p
Examining temporal trends in the production and bioaccumulation of methylmercury in a restored wetland habitat on Brier Island, Nova Scotia
No full textMercury (Hg) is a contaminant of global concern due to its ability to undergo long-range transport from distant sources to sensitive ecosystems. In wetlands, Hg is readily methylated to methylmercury (MeHg) by sulfate-reducing bacteria. MeHg, a neurotoxin, then bioaccumulates and biomagnifies through aquatic food webs. Our study site, Big Meadow Bog (BMB) on Brier Island, Nova Scotia, underwent a water table restoration in 2018 which flooded the bog, altering Hg cycling. To determine the effects of this flooding on the biogeochemical cycling of Hg, outflow surface water was collected over five years (2018-2023) and invertebrate samples were taken over three summers (2021, 2022, and 2023). The filtered water samples were analyzed for MeHg, total mercury (THg), dissolved organic carbon (DOC), and nutrients (PO43-, NO3-, and SO42-), while THg and MeHg were quantified from invertebrate samples. MeHg, DOC, PO43-, and NO3- concentrations were significantly higher in the first year post-flooding and decreased through subsequent years. MeHg, DOC, and NO3- concentrations were all strongly correlated and significantly higher in the summer months than the winter months, indicating that biotic MeHg production was considerably affected by these factors. MeHg concentrations in water were correlated with those in invertebrate tissues, suggesting that this environment is conducive to invertebrate MeHg uptake. Further investigations into the composition of DOC and its role in MeHg cycling as well as the role of nutrients in the bioaccumulation of MeHg is warranted to complete our understanding of the biogeochemical cycling of Hg in altered wetlands.</p
Governing of space and the displacement of the unhoused
No full textThis honours thesis examines the criminalization of homelessness in Kentville, Nova Scotia. Through a critical engagement with municipal by-laws and how public spaces are designed and regulated in the downtown core of the community, I explore the politics of the regulation of space and the impacts on unhoused folks who cannot use the space in the way it was intended to be used. Through arts-based participatory methods and semi-structured one on one interviews, this research centers the voices of folks who have at some point in their lives, or who are currently experiencing homelessness. Drawing on the empirical data collected in this study, I found that participants have diverse perspectives about police (and other legal actors), have experienced feeling ‘othered’ due to their unhoused status, sometimes internalize this ‘othering’, and have desires to feel safe, supported, and a sense of belonging in their rural community. This work contributes a rural perspective to a larger body of sociological and socio-legal work that examines the regulation of public spaces and the criminalization of homelessness.</p
Getting prepared to care: understanding the experiences of caregivers in Nova Scotia
No full textThis thesis explores the challenges of caregivers in Nova Scotia and their barriers to accessing respite care and government support. This thesis is guided by social reproduction theory, the political economy of aging, and the life course perspective. These perspectives help to better understand how unpaid care work is valued in the care economy and why this labour has been largely overshadowed and underappreciated due to neoliberalism and capitalism. This research uses a mixed-methods approach including seven semi-structured interviews with caregivers across the province, which are supplemented with secondary data analysis of the 2018 General Social Survey – Caregiving and Care Receiving. The findings highlight the need for better access to home care services, respite care, and government funds to help caregivers and mediate caregiver burden. Helping caregivers in this manner is a necessary step to avoid a crisis of care and to ensure a better quality of life for caregivers and their care recipients.</p
Effects of insect-induced eastern hemlock (Tsuga canadensis) decline on associated macrofungal communities in Kejimkujik National Park and National Historic Site
No full textFungi are vital decomposers and mutualists which are key to maintaining thriving forest ecosystems; however, fungal community responses to host tree insect disturbances remain poorly understood, including in old-growth eastern hemlock (Tsuga canadensis L.) forests. Eastern hemlock is a foundation species of the Acadian forest (Wabanaki), which is threatened by the invasive hemlock woolly adelgid (Adelges tsugae Annand) (HWA) in eastern North America, including in Kejimkujik National Park and National Historic Site, Nova Scotia, Canada (KNPNHS).To understand how host tree insect disturbances affect subsequent hemlock macrofungal communities, macrofungal community composition before and after a palewinged grey moth (Iridopsis ephyraria) (PWG) outbreak in eastern hemlock forests of KNPNHS was investigated using new collections and a unique long-term fungarium specimen dataset. This study tested the following hypotheses: 1) A unique fungal community potentially associating with eastern hemlock will be identified; 2) A spatial assay comparing fungal communities of hemlock plots will reveal differences in macrofungal communities according to historic PWG damage levels, and; 3) A temporal assay comparing the past and present fungal communities of hemlock plots affected by PWG will show greater changes in fungal communities of plots with more severe PWG damage than in plots with less severe PWG damage.Macrofungi from hemlock plots with different levels historic PWG disturbance were collected in July – November 2021 – 2023. These, and historic specimens (E. C. Smith Herbarium, Acadia University (ACAD)) collected from the same plots, were identified using ITS rDNA barcoding, phylogenetic analysis, and macro-/ microscopic characteristics. In total, 312 specimens were sequenced—266 newly collected specimens and 46 herbarium vouchers. The 847 specimens collected in the present (2021 – 2023) comprised 300 species from 84 genera. Cortinarius (19%), Russula (7.3%), and Amanita (6.3%) were the most common collections in this period. The 1249 specimens collected in the past (1990, 1991, & 1995) comprised 384 species from 59 genera, and Mycena (8.2%), Lactarius (7.2%), and Cortinarius (6.5%) were most commonly collected. Indicator Species Analysis revealed 25 potential hemlock indicator species across all years, but also showed a reduction in the number of indicator species from the past to the present for many plots. Most of the indicator species named were generalists. Multiple Correspondence Analysis demonstrated differences between fungal communities of plots with different levels of historic PWG damage across space, and showed the greatest change across time occurred in plots with the most severe PWG damage.Our results suggest that as HWA infestations intensify in KNPNHS, T. canadensis ecosystems may lose hemlock-preferring macrofungal species and may shift toward more generalist macrofungal communities. This change may prevent the establishment of new hemlock seedings, induce the loss of bacterial communities associated with hemlock macrofungi, and threaten food sources for many organisms, which could permanently alter the hemlock ecosystems of KNPNHS.</p
The Cantor-Conway class
No full textJohn Horton Conway discovered a proper class of numbers called surreal numbers. The surreal number field is a totally-ordered field that contains R and all of Cantor's ordinals. Within it we find infinite numbers as well as infinitesimal numbers. The class of all positive surreal numbers can be partitioned into convex subclass called commensurate classes, and these represent the different "sizes" of numbers. This thesis is an attempt to determine if it is possible to construct fractal objects within the surreal number field in a way that reflects their typical construction within the real number field. We give insight into the answer of this question by defining a surreal analogue to the Cantor set that we call a Cantor-Conway class. Our definition generalizes the base-three representation of the classical Cantor set. We also discuss a method of showing that each member of a particular subset of Cantor-Conway classes is equal to the union of the members of an increasing sequence (indexed by every ordinal number) of full sets, thus mimicking one of the standard constructions of the Cantor set. We think of this as starting with a "seed" set and then growing both "upwards into infinity" as well as "downwards" into the "tiny spaces" between previous points.</p
Acknowledging my privilege: redressing the harms
No full textWithin this work I will be using autoethnography as a methodology to discover examples of interest convergence within the process of decolonizing my instructional practices. I use the word decolonize as a process in which “structures and practices [are] deployed in order to replace those of colonialism” (Grafton & Melancon, 2020, p. 135). I argue that after I acknowledged the need to decolonize my practice I went through a process that used Critical Race Theory’s tenet of interest convergence to change aspects of my instructional practices. Interest convergence is “the place where the interests of Whites [sic] and people of color intersect” (Ladson-Billings, 1998, p. 12). I discovered through this autoethnographic process that I was willing to change my instructional practices only if what I was changing fit within the colonial structure I am comfortable working. I use the nine First Peoples Principles of Learning to illustrate how my perceived decolonization perpetuated colonial understandings. This work uses storytelling and song writing to look at sites of epistemic violence I may have caused while using interest convergence to change my instructional practices. I will also outline how using the five steps of the stages of change can facilitate educators moving through their own process of decolonizing their instructional practice. I recognize decolonizing my practice is an ongoing process and that I will never truly decolonize myself.</p
Pollinators in eastern hemlock forests: non-target effects of imidacloprid basal-bark sprays for hemlock woolly adelgid management and efficacy of sampling methods
No full textHemlock woolly adelgid (Adelges tsugae Annand (Hemiptera: Adelgidae); HWA), a small insect originating from East Asia, was inadvertently introduced into the eastern United States in the 1950s. Since its introduction, the invasive insect rapidly spread through the range of eastern hemlock (Tsuga canadensis Carrière (Pinaceae)) and Carolina hemlock (T. caroliniana Engelmann (Pinaceae)), causing high tree mortality. In 2017 HWA was detected in Nova Scotia, Canada, where it is threatening local eastern hemlock stands and ecologically important habitats. Numerous management techniques, including silvicultural approaches, biocontrol, host-resistance research, and chemical control are currently being investigated to help manage the spread of HWA and mitigate damage to and loss of host trees. Treatment of infested trees with the neonicotinoid insecticide imidacloprid has shown high efficacy in the United States and Canada, stopping tree decline and preventing mortality. While effective against HWA, the use of imidacloprid has raised concerns regarding its potential impacts on non-target arthropods inhabiting hemlock forests. Many studies have explored the non-target effects of imidacloprid treatment for HWA management on arthropods, however, its effects on pollinators inhabiting eastern hemlock forests remain unclear. We conducted a two-year study (2021–2022) to explore the non-target impacts and risks associated with imidacloprid basal bark sprays for HWA management on two pollinator groups, bees (Hymenoptera: Apoidea: Anthophila) and flower flies (Diptera: Syrphidae) in eastern hemlock forests of Nova Scotia, Canada. Our objectives were to evaluate changes in the abundance, richness, and community composition of bees and flower flies before and after treatment and between treated and untreated (control) sites, and to assess imidacloprid concentrations in flowers within treated forest plots to determine potential risks to pollinators. Furthermore, we aimed to evaluate the efficacy of three collection methods, targeted sweep netting, colored pan traps, and blue vane traps, to provide tools for future monitoring of pollinators in this habitat. Although we did detect variation among the pollinator communities in the study, our findings indicated no clear evidence of adverse effects on pollinators from imidacloprid basal bark sprays. We did, however, detect imidacloprid in flowers at concentrations potentially harmful to pollinators, especially near treated trees, which underscores the need for further research into potential risks, especially if repeated and large-scale treatments are planned in the future. Additionally, we found that blue vane traps are particularly effective for sampling bees and flower flies in this habitat, though colored pan traps and targeted sweep netting may offer complimentary insights into the present pollinator community. Our findings on sampling method efficacy will equip researchers with the necessary tools to accurately monitor pollinator populations in eastern hemlock forests, aiding to evaluate effects of imidacloprid basal bark sprays on pollinators in the future.</p
An apPEELing view: a phenomic and genomic analysis of apple colour variation
No full textApples (Malus X. domestica Borkh.) are a vital fruit crop grown for fresh eating, alcoholic cider, and juice. Apple fruit colour is a critical trait for consumer acceptance of apples and thus breeders are incentivized to select for desirable apple colour traits (phenotypes). However, breeding new apple cultivars is a time-consuming and expensive process due to a lengthy juvenile period before the tree produces fruit which can be evaluated. Increasingly, genomic tools such as marker-assisted selection are being used to accelerate fruit breeding. Over 12,000 photographs of apples from Canada's Apple Biodiversity Collection were taken and quantified using the ColourQuant pipeline to identify 18 colour phenotypes for 531 unique genetic accessions. These same accessions were also sequenced to identify ~250,000 genetic markers. After analyzing variation in fruit colour, the 18 traits were linked with the genetic data to perform genome-wide association studies to determine how variation in genotype influences phenotype. This demonstrated that apple colour is strongly correlated with a 1505.857kb region on chromosome 9, located near the MYB1 gene, indicating that apple colour variation is likely a monogenic trait primarily controlled by this MYB transcription factor making it a strong candidate for genomics-assisted breeding.</p