Browsing Department of Biology Graduate Theses by Title
Now showing items 280-299 of 321
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Seasonal Controls on Litter and Soil Carbon and Nutrient Cycling in Arctic Tundra Ecosystems and Potential Impacts of Climate Change
(2016-01-29)Climate change is leading to warmer temperatures and greater snowfall in Arctic regions. Microbial decomposition activities are strongly regulated by temperature, and therefore climate warming is projected to enhance decay ... -
Sedimentary Midges as Paleoindicators of Deep-water Oxygen Conditions Across a Broad Trophic Gradient in Boreal Lakes
Cultural eutrophication, the addition of excess nutrients to an aquatic system, is a significant water quality concern that often promotes excess algal growth and deep-water oxygen depletion. Deep-water oxygen also influences ... -
Sensory exploitation in a sit-and-wait predator: Exploring the functions of stabilimenta in the banded garden spider, Argiope trifasciata
(2009-09-28)Attracting prey by exploiting a visual sensory bias is a common theme in stationary predators across many taxa, particularly for obligate ambush predators, such as orb-weaving spiders, because they construct complex prey ... -
Serine-451 phosphorylation of bacterial-type phosphoenolpyruvate carboxylase by a calcium-dependent protein kinase links calcium signaling with anaplerotic pathway control in developing castor oil seeds
(2013-09-03)Phosphoenolpyruvate (PEP) carboxylase (PEPC) is a tightly controlled enzyme situated at a pivotal branchpoint of plant C-metabolism. Two physically and kinetically distinct oligomeric classes of PEPC exist in the endosperm ... -
Should I Stay or Should I Go? Alternative migratory strategies in partially migratory western bluebirds (Sialia mexicana)
Partial migration, which occurs when only some animals in a population migrate, is ubiquitous. However, despite numerous studies investigating how partially migratory systems are controlled, we know relatively little about ... -
Shrub expansion in the low Arctic: The influence of snow and vegetation feedbacks on nitrogen cycling
(2009-09-19)Climate change has coincided with expansion of deciduous shrub species in the Arctic. Increased deciduous vegetation in the tundra could have profound implications on regional climate, carbon balance, and biogeochemical ... -
Silver Nanoparticles and the Plant-Associating Abilities of Rhizobiaceae Bacteria
(2016-07-04)The use of nanoparticle technology in consumer products has been increasing due to their broad-spectrum antimicrobial properties. Specifically, silver nanoparticles (AgNPs) can demonstrate distinct physiochemical properties ... -
Soil carbon and nitrogen dynamics along replicated chronosequences of abandoned agricultural lands in southeastern Ontario
(2007-12-20)Widespread abandonment of agricultural land has occurred in northeastern North America over the past two centuries. Soil carbon often increases as sites naturally regenerate towards perennial grasslands or forests. ... -
Spatial, temporal and dendrochronological comparisons of mercury in Ontario deciduous trees
(2007-12-20)Mercury (Hg) research in Ontario has centered on aquatic environments since fish can be a significant source of methylmercury for humans. Interactions between terrestrial and aquatic environments in regards to the Hg ... -
Spawning Black Bass and the Invasive Round Goby in Lake Ontario and the St. Lawrence River
This thesis examined the relationships between the invasive Round Goby (Neogobius melanostomus) and the economically important recreational fish species, Smallmouth Bass (Micropterus dolomieu) and Largemouth Bass (Micropterus ... -
Species response to rapid environmental change in a Subarctic pond
(2013-10-02)Unprecedented rates of anthropogenic environmental change have resulted in dramatic decreases in biodiversity worldwide. In order to persist during changes in both the abiotic and biotic environment resulting from anthropogenic ... -
Sperm Production and Variance in Sperm Quality
(2009-09-26)An unusually high level of inter- and intraspecific variability in spermatozoa has been well documented. However, recent evidence indicates that the level of variation within spermatozoa differs markedly across taxa. In ... -
Spike train propagation in the axon of a visual interneuron, the descending contralateral movement detector of Locusta migratoria
(2011-10-07)Neurons perform complex computations, communications and precise transmissions of information in the form of action potentials (APs). The high level of heterogeneity and complexity at all levels of organization within a ... -
Srk1 kinase suppresses mitosis in response to heat stress in fission yeast
(2011-08-10)Fission yeast Srk1 kinase is essential for cellular responses to extracellular stimuli. It is activated downstream of the MAPK Spc1 and participates in controlling mitotic entry by directly phosphorylating and inhibiting ... -
Stress responses in an outbred, wild-derived hamster, Phodopus campbelli: Individuality in the cortisol response to acute restraint stress and the absence of strong association with behavioural responses to acute restraint
(2009-02-11)Glucocorticoid reactivity is often used as a biomarker of emotional stress status in animals and man. Likewise, behavioural responses of individuals to standardized stresses are also widely used to assess the magnitude of ... -
The Synthesis of Elemental Selenium Particles by the Cyanobacterium Synechococcus leopoliensis
(2012-09-18)In the present study the light dependent biosynthesis of spherical red elemental selenium Se(0) granules (average size of 220 nm) by the cyanobacterium Synechococcus leopoliensis when exposed to high selenite concentrations ... -
Targeted over-expression of hsp22 and the maintenance of locomotor activity of third instar larvae of Drosophila melanogaster at high temperatures
(2007-10-02)Hsp22 has been implicated in stress tolerance and longevity in various organisms though its role in Drosophila melanogaster larval thermal tolerance has not yet been investigated. I undertook this project to determine if ... -
TEMPERATURE MODULATION OF THE EFFECTS OF REPETITIVE ANOXIA ON POTASSIUM HOMEOSTASIS IN THE BRAIN OF Drosophila melanogaster
(2012-01-30)Oxygen can be limited at the environmental (e.g. flood-prone burrows) or cellular (e.g. stroke, heart attack) levels. O2 deprivation in nervous tissue depolarizes cell membranes, incrementing extracellular potassium ... -
Testing the role of Baja California generating biodiversity: A test case characterizing the population genetic structure of Cassin's auklet (Ptychoramphus aleuticus)
(2012-09-28)Characterizing the population genetic structure of a species can provide insight into isolating effects of local adaptation and genetic drift, and homogenizing effects of gene flow. The relative interplay between gene flow ... -
Tetrahydrofuran Hydrate Inhibitors: Ice-Associating Bacteria and Proteins
(2009-03-31)Ice-associating proteins (IAPs) are proteins that interact directly with ice crystals, either by offering a site for nucleation, i.e. ice nucleating proteins (INPs), or by binding to nascent crystals to prevent addition ...