Life Sciences Commons^™

The Effect Of Dietary Thiaminase On Cardiac Function And Morphology In Lake Trout (Salvelinus Namaycush), Peter Baker

Electronic Thesis and Dissertation Repository

Thiamine deficiency from the consumption of invasive, high-thiaminase prey fishes is considered to be a major barrier for lake trout restoration in the Great Lakes. In fishes, an understudied aspect of thiamine deficiency is its effect on cardiac function. I examined the effects of dietary thiaminase on cardiac function and morphology in lake trout, specifically as they relate to thermal tolerance. Two hatchery strains of lake trout (Seneca and Slate) were raised on a control or thiaminase diet for nine months. The thiaminase diet was associated with significant ventricle enlargement, impaired cardiac function, and reduced thermal tolerance; these effects were …

Temperature-Dependent Developmental Plasticity In The Cardiorespiratory System Of Atlantic Salmon, Carlie A. Muir

Electronic Thesis and Dissertation Repository

Anthropogenic climate change is expected to have pervasive impacts on the performance and viability of fishes, as increasing temperatures create aerobically constrained environments for many species. Given the rapid rates of projected temperature increases, it is critical to evaluate the capacity for fish to respond to a changing thermal environment through phenotypic plasticity. In this thesis, I examined the capacity for developmental plasticity in the thermal performance of juvenile Atlantic salmon (Salmo salar) reared under two thermal regimes from fertilization, and investigated potential mechanistic underpinnings within the cardiorespiratory system. Cardiac performance was examined using a noninvasive Doppler echocardiograph …

Patterns And Mechanisms Of Intraspecific Trait Variation Across Thermal Gradients In A Marine Gastropod, Andrew R. Villeneuve

Masters Theses

As the earth’s climate changes due to anthropogenic emissions, it has increasingly become an imperative within the ecological community to understand existing species adaptations to climate change. Much focus has been paid to how a species might react to climate change, but the role of locally adapted traits and responsible environmental mechanisms have received less attention. Quantifying how sublethal (e.g. growth rates) and lethal (e.g. thermal tolerance) trait performance vary between populations can thus improve our understanding of how populations, and the entire species, will react to climate change. Here, I quantified the spatial patterns of performance of several traits …

Living On The Edge: Thermophysiology Of The Southern Flying Squirrel At Its Northern Range Margin, Vanessa R. Hensley

Electronic Theses and Dissertations

Climate change has the potential to upset entire ecological systems, making predictive models of the utmost importance. The incorporation of physiological parameters into predictive models not only bolsters their accuracy but also provides a mechanistic explanation for ecological changes already observed and those yet to come. North American flying squirrels, for example, have already experienced dramatic range shifts northward over recent decades, with climate change being the suspected driver. While other studies have focused on warming winter temperatures, I explored the hypothesis that rising summer temperatures were driving the observed range shifts. Unable to find a reliable population of the …

Comparative Thermal Ecology Of Coastal And Inland Pacific Rattlesnakes (Crotalus Oreganus), Hayley Layne Crowell

Master's Theses

Global biodiversity is declining as a direct result of anthropogenic climate change. Ectothermic species have become focal organisms for studying the ecological effects of altered climates due to the clear relationship between environmental temperatures and ectotherms’ basic physiological functions. Historically, examinations of these effects have focused heavily on heliothermic lizards, and most others have tended to focus on single populations or sympatric species within a single community. Addressing the longterm energetic implications of environmental temperature variation will provide valuable insight into the cascading physiological effects that certain populations or species may experience as a result of altered climates.

In this …

Thermal Performance Covaries With Environmental Temperature Across Populations Of Atlantic Salmon (Salmo Salar), Kayla J. Harding Gradil

Electronic Thesis and Dissertation Repository

Global climate change is projected to have widespread effects that could threaten the viability of natural populations. Physiological processes of aquatic ectotherms critically depend on their thermal environment, such that the optima for performance often correspond to environmental temperatures. Given predicted changes in aquatic thermal environments, it is increasingly important to understand organism’s underlying physiological mechanisms utilized to cope with these changes. Here, I show that three populations of Atlantic salmon (Salmo salar) are narrowly adapted to their native summer temperatures, such that thermal tolerance is optimized near average temperatures and collapses near peak temperatures. Further, I found …