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Intra-Population Variation Of Hair And Fingernail Stable Hydrogen, Oxygen, Carbon And Nitrogen Isotopes In London, Ontario, Canada Residents During The Covid-19 Pandemic, Sawyer C E Rowe

Electronic Thesis and Dissertation Repository

Lockdowns and travel restrictions during the COVID-19 pandemic forced a significant fraction of London, Ontario, Canada residents to remain in one location for long enough to reach isotopic equilibrium with their primary drinking water source(s). This situation created ideal natural conditions for measuring the isotopic fractionation between the stable hydrogen and oxygen isotopes of drinking water and hair or nail tissues, and for determining the magnitude of intra-population variation in tissue δ²H and δ¹⁸O. Hair and nail of participants who reported exclusively drinking London municipal tap water spanned much larger δ²H and δ^{18 …}

Using Stable Isotopes To Understand Survival Versus Extinction Of Late Pleistocene Muskoxen, Stephanie Mabee

Electronic Thesis and Dissertation Repository

This thesis uses stable isotopes to investigate the adaptive advantages of Ovibos moschatus, a muskox, relative to now-extinct Pleistocene megafauna in eastern Beringia (Yukon Territory and Alaska), including another muskox Bootherium bombifrons. Ecological niches were defined for Ovibos and Bootherium using stable carbon and nitrogen isotope compositions of bone collagen. Plant remains trapped in modern Ovibos molars were used to determine the carbon and nitrogen isotope collagen-diet discrimination factors, which were then applied to ancient specimens. Ovibos possessed larger isotopic – and hence ecological – niches than Bootherium across eastern Beringian sites. The larger niche suggests that Ovibos …

Origins Of Stable Isotopic Variations In Late Pleistocene Horse Enamel And Bone From Alberta, Nicolle S. Bellissimo

Electronic Thesis and Dissertation Repository

Oxygen and carbon isotopic measurements of coevally formed bone and tooth enamel bioapatite from a modern equid show that these tissues record drinking water and diet isotopic signals in an identical fashion. Hence, data for both tissues can be combined to track movement, dietary changes, and seasonal variability over the animal’s lifetime, and climatic variability over longer time periods. This tool was tested for horses using ten paired tooth and bone samples to reconstruct conditions in Alberta during the Late Pleistocene. While post-mortem isotopic alteration confounded interpretation of the results, two key findings emerged: (i) pre- and post-Last Glacial Maximum …

Late Pleistocene Climate And Proboscidean Paleoecology In North America: Insights From Stable Isotope Compositions Of Skeletal Remains, Jessica Z. Metcalfe

Electronic Thesis and Dissertation Repository

This thesis uses the carbon, nitrogen, and oxygen isotope compositions of mammoth (Mammuthus) and mastodon (Mammut) skeletal remains to reconstruct paleoclimate and paleoecology in Late Pleistocene North America. Analytical methods, sampling strategies, environmental adaptations and seasonal behaviors of proboscideans were investigated.

Reliable and reproducible results are crucial for a study of this nature. A persistent methodological problem in the isotope analysis of structural carbonate in bioapatite was solved by reacting bioapatite under “sealed vessel” conditions.

Growth rate determinations are critical for designing sampling strategies and interpreting results. Histological and isotopic measurements demonstrated variations in enamel growth …