Geography - Theses, Dissertations, and other Required Graduate Degree Essays

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Arctic deltas as biogeochemical hotspots affecting the delivery of nutrients and dissolved organic matter to the Arctic Ocean

Author: 
Date created: 
2018-12-04
Abstract: 

The Mackenzie River and Delta were sampled during hydrologically-defined seasons in four consecutive years to assess 1) the importance of sampling during the rising limb of the flood hydrograph (rising freshet) for accurately characterizing constituent fluxes and quality, and 2) how floodplain processes affect discharge to the Arctic Ocean. Including rising freshet samples had a modest effect on annual sediment and nutrient flux estimates for the Mackenzie River (-9 to +26% difference). Nutrient quality was very different during the rising freshet, however, with relatively high concentrations of carbon-rich dissolved organic matter (DOM), phosphorus-rich particles, and nitrogen-rich inorganic nutrients. Mackenzie River DOM quality was relatively fresher, more terrigenous, and younger (radiocarbon values suggesting ages < 15 years) during the rising freshet, indicating a high proportion of recently-fixed vascular plant material. The Mackenzie was also a net absorber of carbon dioxide during the rising freshet (-112 to -258 mg-C m-2 d-1), switching to net emission after peak flood. Open water (freshet through summer) fluxes of dissolved organic carbon (1.4 Tg) and lignin (7.1 Gg) in the Mackenzie River were greater than previously reported total annual fluxes, likely due to the inclusion of rising freshet data herein. Optical parameters, and statistical relations between fluorescence components derived from Parallel Factor Analysis (PARAFAC; six in delta channels, five in delta lakes) and chemical biomarkers (e.g. lignin phenols), suggest substantial modification of DOM in delta lakes and on the floodplain during downstream transport. When incubated (14 days) under solar conditions similar to those on the floodplain, Mackenzie River DOM (isolated during peak flood) experienced photochemical changes on par with those observed in delta lakes over the entire open water period. Photodegraded DOM significantly reduced abundances but fueled per-cell growth in bacterial populations from delta habitats, indicating rapid shifts in community composition. Gradients in chemical biomarkers were related to the delta-wide gradient of lake hydrological connectivity. These results emphasize the importance of the rising freshet in accurately characterizing Mackenzie River DOM quality and carbon fluxes, and the need to sample downstream sites in lake-rich circumpolar deltas to constrain flux estimates and characterize discharge to the Arctic Ocean.

Document type: 
Thesis
File(s): 
Senior supervisor: 
Lance Lesack
Department: 
Environment: Department of Geography
Thesis type: 
(Thesis) Ph.D.

Composition of aquatic microbial communities and their relation to water-column methane cycling among Mackenzie Delta lakes, western Canadian Arctic

Date created: 
2018-11-29
Abstract: 

Seasonal dynamics of water-column microbial communities and methanotrophs were monitored in six lakes of the Mackenzie River Delta using gene sequencing of 16S rRNA gene and qPCR of the 16S rRNA and methane monooxygenase (pmoA) genes. Selected lakes varied in biogeochemistry based on annual river-to-lake connection times, which we hypothesized would impact bacterial community composition and methanotroph relative abundance. River-to-lake and seasonal influences on carbon bioavailability and quantity, nutrients, temperature and flooding correlated with seasonal changes in microbial composition. Methanotroph groups including Methylobacter and methylotrophs Candidatus Methylopumilus and Candidatus Methylophilaceae were detected in all lakes but at higher relative abundance in the winter and spring when lake-water methane concentrations were highest. Open-water methanotroph abundance was highest in spring. In experimental enclosures, methanogenesis was detected in oxygenated lake-water and rates varied by lake type. Nutrient enhancements altered microbial composition and increased rates of methane oxidation with increasing lake isolation.

Document type: 
Thesis
Senior supervisor: 
Lance Lesack
Department: 
Environment: Department of Geography
Thesis type: 
(Thesis) M.Sc.

Streamflow characteristics of intermittent streams in the Okanagan, British Columbia, Canada

Author: 
Date created: 
2018-08-24
Abstract: 

Even though intermittent streams are prevalent in every hydrologic region of the world, there has been relatively little research on the flow regime of intermittent streams. Intermittent stream flows affect aquatic biota, water quality, and quantity in downstream perennial streams. This study focused on (1) the differences in the streamflow regime characteristics of perennial and intermittent streams and (2) the spatial and temporal variation in streamflow along one intermittent stream (Long Joe Creek) in the Okanagan Basin. Differences between intermittent and perennial streamflow regimes included rates of recession, steepness of flow duration curves, start of freshet, and fall discharge variability. Lack of streamflow data for truly intermittent streams made it difficult to assess the reasons for these differences. The observations along Long Joe creek highlighted the very large spatial and temporal variability in streamflow in intermittent streams and the need to focus monitoring on multiple locations.

Document type: 
Thesis
File(s): 
Senior supervisor: 
Dr. Lance Lesack
Department: 
Environment: Department of Geography
Thesis type: 
(Thesis) M.Sc.

"It's yours": Tenant experiences of home and care in women's non-profit housing

Author: 
Date created: 
2018-08-16
Abstract: 

Contemporary discussions among politicians, media, and the public about housing tend to focus on housing’s value as a commodity, rather than the potential social value of housing as home. Yet, social scientists argue that it is housing’s value as home, its use value, that is crucial to our everyday lives. This disconnect raises a question of how home relates to housing, particularly as policymakers seek ways to provide adequate housing to growing urban populations, further exacerbated within the context of ongoing housing crises in the global North. Moreover, women face unique barriers when accessing housing, including issues related to structural social and economic inequalities. Drawing on feminist methodologies to examine a case study of non-profit housing for women in Vancouver, Canada, this thesis explores the relationship between gender, care work, the production of home, and tenants’ experiences of their housing. Connecting literatures of home, care work, and a feminist ethic of care, results indicate that tenants’ experiences of home are co-produced through the built environment and organizational practices of these non-profits, and the relationships of care that tenants have with their neighbours. Further, relationships of care in these spaces are multifaceted: staff provide care to tenants, and tenants also provide care to each other. I argue that home in this housing can be a collective experience, centred around tenants’ feelings of care and community for each other, but these experiences are also situated within complex relationships of power that exist throughout the non-profit organizations. I conclude with recommendations to improve the provision of housing for women on low- or fixed-incomes, where the social value of housing, as home, is emphasized.

Document type: 
Thesis
File(s): 
Senior supervisor: 
Eugene McCann
Department: 
Environment: Department of Geography
Thesis type: 
(Thesis) M.A.

Bark beetles and wildfire: influence of overlapping disturbances on wood and light in a sub-boreal headwater system

Author: 
Date created: 
2018-08-21
Abstract: 

Forest disturbances provide an important link between terrestrial and freshwater ecosystems. In this study I ask 1) how the recruitment of wood to streams varies depending on whether trees were dead or alive prior to a wildfire; and 2) what is the quantitative contribution of fallen wood spanning small streams to stream light. I found that wood recruitment is affected by overlapping, short-interval disturbances of insect outbreak followed by wildfire since being killed prior to fire makes a tree twice as likely to topple immediately post-fire. Additionally, the toppled wood lying above-stream provided a detectable buffer to incoming light in a post-fire landscape. The effects of disturbance history on stream communities and microclimate via wood warrants further study to improve our understanding of how landscape scale terrestrial processes are drivers of localized and watershed-scale changes to aquatic primary productivity and thermal variability.

Document type: 
Thesis
File(s): 
Senior supervisor: 
Lance Lesack
Department: 
Environment: Department of Geography
Thesis type: 
(Thesis) M.Sc.

The international health landscape of Cozumel Island, Mexico

Author: 
Date created: 
2018-02-09
Abstract: 

Cozumel Island is the largest of Mexico’s eastern islands. It is the Western Caribbean’s most popular cruise destination, and is well-known for its crystalline waters and mosaic reefs that attract dive enthusiasts from around the globe. Joining the millions of international tourists that set foot upon the island each year, Cozumel is also home to a significant community of lifestyle and retirement migrants. Recognising this conglomeration of global bodies, and that some will inevitably require medical assistance, this dissertation presents an exploratory case study of Cozumel Island’s health landscape as an international phenomenon. It is driven by three primary objectives that seek to unpack the aesthetic nature of Cozumel Island’s international care settings, determine the intersecting mobilities at play within the island’s international health landscape, and understand both the provision and reception of care for international patients on Cozumel Island. Analysing field experiences, photographs, and semi-structed interviews with international lifestyle and retirement migrants, as well as health care providers working within the island’s private hospitals and medical clinics, three discrete analyses provide insight into Cozumel Island’s international health landscape. First, the aesthetics of pharmaceutical signage are explored and unpacked within the sociolinguistic framework of the linguistic landscape to consider how tourists visiting Cozumel Island might interpret such markers of medicinal merchandise, revealing imagery that positions pharmaceuticals as both souvenirs and suggestions of personal health autonomy. Second, international lifestyle and retirement migrants’ perceptions and beliefs about Cozumel’s pharmacy sector are analysed, revealing a number of concerns that exist in relation to participants’ spatial mobilities. Finally, health care workers’ experiences of treating international tourists are unpacked and found to entail multiple challenges that can preclude effective and safe treatment. When taken together, and as products of this dissertation’s objectives, these analyses situate Cozumel Island’s international health landscape as component within a complex archipelago of tourism, health and other mobilities, that produce it as connected, dynamic, and a continuously emergent setting of transnational health processes.

Document type: 
Thesis
File(s): 
Senior supervisor: 
Valorie Crooks
Department: 
Environment: Department of Geography
Thesis type: 
(Thesis) Ph.D.

Spatial Narratives of Property Loss: Social memory and the dispossession of Japanese Canadian-owned property in British Columbia

Author: 
Date created: 
2018-01-25
Abstract: 

This project informs an emergent literature on memory and property. More specifically, it uses a geographical perspective to analyze memories of property loss. The case study – a sample of thirty-one oral histories related to the dispossession of Japanese-Canadian-owned property during the 1940s – comes from the Landscapes of Injustice (LoI) SSHRC-funded project. LoI addresses haunting across the social memory of Canada; by sharing spatially-grounded life stories, interview participants unsettle under-recognized meaning attached to property loss. To embrace the centrality of space and place to this reckoning, I frame these “spatial narratives” around the processes of hauntology in les lieux de mémoire (sites of memory) (Derrida, 1994 & Nora, 1989). I focus on three distinct themes across the narratives and to analyze them, draw from the work of three contemporary property theorists. Citizenship explores the political undertones of “Canadian” property ownership and loss (Singer, 2000); Investment identifies the monetary and non-monetary values put into property (Becher, 2014); and Belonging details important networks that structure property and create unique experiences of belonging (Keenan, 2015). As I recognize the complex nature of social memory, I also illustrate the ways in which these themes interconnect. Finally, I argue that spatial narratives from LoI gesture at a deeper and wider story of property; at the intersection of social memory and property, there is a window into the layered history of remembering and forgetting dispossession in colonized British Columbia.

Document type: 
Thesis
File(s): 
Senior supervisor: 
Nicholas Blomley
Department: 
Environment: Department of Geography
Thesis type: 
(Thesis) M.A.

Scour pool incision in bedrock canyons

Author: 
Date created: 
2018-04-30
Abstract: 

A flume experiment was conducted to investigate the effect of lateral constrictions on the initiation and evolution of scour pools in bedrock canyons. Results show that lateral constriction can initiate the formation of a scour pool. Deceleration of the flow upstream of the constricted canyon promotes alluviation, while flow acceleration through the canyon prevents a permanent sediment cover from developing. The elevation difference upstream and through the canyon causes flow and sediment to plunge towards the bed, enhancing scouring. The erosion rate was controlled by sediment size and presence of alluvial cover. Scour pools reach equilibrium morphology for a given constant discharge and sediment supply by cutting a slot, which then gets deep enough to maintain a permanent alluvial cover, protecting the bed from further vertical erosion and promoting lateral erosion. Shear stress calculated from the near-bed velocity gradient and Reynolds shear stresses are counterintuitively large in alluviated areas and low in places where the bed is clear of sediment. This highlights a general problem with using shear stress as a predictor of alluviation and rock erosion patterns in highly non-uniform flows. However, changes in near-bed velocity had strong correlations with alluviation patterns and erosion rate, suggesting near-bed velocity may be a more practical way to calculate rock erosion rates in non-uniform flows.

Document type: 
Thesis
File(s): 
Senior supervisor: 
Jeremy Venditti
Department: 
Environment: Department of Geography
Thesis type: 
(Thesis) M.Sc.

The modern coarse-grained fan deltas of south-western British Columbia, Canada: a geomorphologic study

Author: 
Date created: 
2018-03-29
Abstract: 

The geomorphology, sedimentology, and depositional architecture of six modern coarse-grained fan deltas in south-western British Columbia, Canada are examined. Methods included geomorphologic mapping, morphometric analyses, section logging, sedimentary facies mapping, and ground-penetrating radar (GPR) surveying. The fan deltas exhibit Gilbert-type depositional architectures; major depositional sub-environments include: (i) subaerial fan-delta plains formed by alluvial processes and mass-wasting processes (debris flows and sheetfloods); (ii) beach environments that exhibit complex geomorphologic and sedimentologic characteristics, having been supplied sediments by terrestrial processes and being (re-)shaped by coastal sediment-reworking processes; and (iii) steep-gradient (≤~35º) fan-delta front environments that are characterized by decameter-scale foreset beds. Depositional models and a suite of diagnostic geophysical characteristics are proposed for the fan deltas and the fan-delta beach environments.

Document type: 
Thesis
Senior supervisor: 
Jeremy Venditti
Department: 
Environment: Department of Geography
Thesis type: 
(Thesis) M.Sc.

Walkability and connectivity: unpacking measures of the built environment

Date created: 
2017-12-07
Abstract: 

The creation and replication of walkability indices uses geographic information systems (GIS) and warrants exploration of assumptions made implicit by different research disciplines. Most methods of measuring walkability variables – residential density, street connectivity, and land-use mix – lack contextual rationale for inclusion in walkability indices. Furthermore, walkability indices used in contemporary literature themselves are in conflict not only with each other, but also with human spatial behavior. This thesis first compares three walkability indices to make explicit the various ontologies that result as a consequence of choices and calculation of walkability variables. The second article then explores ontological distinctions between connectivity measures and their subsequent effects on methodology and interpretation. Given non-linear patterns of human mobility in activity spaces, this last part explores granular scales of connectivity measures that can better represent the built environment.

Document type: 
Thesis
File(s): 
Senior supervisor: 
Nadine Schuurman
Meghan Winters
Department: 
Environment: Department of Geography
Thesis type: 
(Thesis) M.Sc.