A stalagmite was collected in the Salón de la Permencia of the Majaguas Cave, that is a part of the Majaguas-Cantera Cave System in Cuba. The use of this stalagmite as a natural climate archive is advantageous not only because stalagmites can record continuous episodes of growth that are thousands of years in duration but also because they are easily and reliably dated, using U/Th dating methods. With this method, the stalagmite was reliably dated to 100 ka and was still active when removed from the cave for analysis. The stable isotopes of oxygen and carbon from this stalagmite from Western Cuba presents information of significant influencing factors on Caribbean precipitation records, and past climatic events during the Pleistocene. Due to the lack of high- resolution records for Western Cuba, this study verifies and adds to our knowledge of past climate variability for the Cuban region and the Caribbean as a whole. The δ18O data in MCS-01 shows a pattern that is very similar to the D-O and Heinrich events clearly recorded in the NGRIP ice core, especially at ~82ka and between 78-70ka. This study provides a continuous precipitation record for the area during the Pleistocene, allowing a greater understanding of the climate drivers that have had an impact on past precipitation patterns in this region.

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No description available.

Through stable isotope analysis of human tooth dentine, this thesis investigates breastfeeding and weaning patterns in relation to rickets in a sample of sub-adults (n=12) interred in the nineteenth century sub-adult cemetery located at the Church of the Trinitarias in Madrid, Spain. The main objectives of this research are to create early life feeding histories for each individual using dentine serial sectioning techniques and apply these histories to investigate the relationship between breastfeeding, weaning, and vitamin D deficiency. The early life feeding histories allows for the determination of the onset and complete age of weaning at an individual level. These stable isotope data are then used to estimate general trends in breastfeeding and weaning practices in nineteenth century Spain. The results of this study indicate that the onset age of weaning for most of the individuals in this sample was between 10 and 14 months of age. The age at which breastmilk consumption stopped entirely was more difficult to estimate, however, in individuals that did show evidence of completed weaning, it was estimated to occur around the age of three. These ages are slightly higher than those discussed in historical sources for nineteenth century Spain. When these results are compared to contemporaneous, more industrialized, European countries the comparison shows that the initialization of weaning occurred slightly later and was a more gradual process in this Spanish sample. The results also demonstrate that there is no direct relationship between weaning patterns and the occurrence of skeletal vitamin D deficiency. It may be that the high prevalence of vitamin D deficiency is linked with the nuances of breastfeeding and other biocultural variables, such as a lack of sun exposure, an inadequate weaning diet, or childcare practices. / Thesis / Master of Arts (MA)

Yes / Here we present a novel method which allows the measurement of the stable isotope ratios of carbon (δ13C) and nitrogen (δ15N) from much smaller samples of dentine than previously possible without affecting the quality parameters. The reconstruction of the diet of past populations using isotopic analysis of bone collagen is a well-established tool. However, because of remodelling of bone throughout life, this gives a blurred picture of the diet. The analysis of δ13C and δ15N from tiny increments of dentine utilizes tissue that does not remodel and permits comparison, at the same age, of those who survived infancy with those who did not at high temporal resolution. This new method has been tested on archaeological teeth from two sites: three molar teeth from the 19th Century Kilkenny Union Workhouse Famine cemetery, Ireland; and three from the Anglian (5-7th centuries AD) cemetery at West Heslerton, Yorkshire, England, selected on the basis of their varied preservation. The methods of incremental dentine sectioning described in Beaumont et al (2013)[1] were carried out and a sub-section removed prior to denaturing and lyophilisation. The two sample sets, dentine and collagen from each section, were measured by isotope ratio mass spectrometry. The profiles produced from each of the six teeth studied show close correlation in isotope ratios indicating that demineralized dentine which has not been denatured and lyophilised produces isotope ratios comparable with dentine collagen. This finding allows analysis of extremely small samples of dentine which could previously not be measured using current instruments and methods.

Lizard ecology through time is largely unknown. Understanding ecology is important because of today’s drastic climate change, but this is not a unique event. Early Cenozoic hyperthermals were comparable to the perturbations currently experienced by living species. Understanding ecology through time must acknowledge the dynamic relationship between an organism and its environment on multiple scales. Ecological inferences can be based on form equaling function, correlating certain features (e.g. leaf-shaped dentition) with certain behaviors (e.g. herbivorous diet). Though this applies to specific taxa, there are confounding examples. Ecology can also be inferred through indirect means, but these are disconnected from the taxon of interest. Stable isotope geochemistry, however, provides an independent test. I analyzed stable isotope ratios (δ¹⁸O, δ¹³C) from enamel, providing new data on the connection between morphology, diet, and environment. I find a trophic separation in δ¹³C, and indications of aridity through δ¹⁸O. I applied this framework to extinct lizards from an Early Eocene (Wa4) assemblage, a key time between two major global warming events (Paleocene-Eocene Thermal Maximum and Early Eocene Climatic Optimum). I identify xenosaurid and glyptosaurine squamates and alethinophidian snakes. The xenosaurid is one of the youngest representatives of Restes rugosus, and I provide the first testable hypothesis of its ecology. These δ¹⁸O values corroborate hypotheses of a wet, tropical environment, and the δ¹³C values indicate an insectivorous or carnivorous diet for both taxa. My study provides an independent test of ecology of both extant and fossil lizards, with implications for differing survivorship throughout the early Cenozoic. / MS / We know little about the diet and habitat of lizards. We have a limited knowledge of these characteristics in living species, but these represents a fraction of the total number of all lizard species that have ever lived. There are several ways to try to understand the ecology of an animal. We can observe it directly, we can infer things about it from comparisons to other living species, or we can make inferences through indirect proxies. All of these methods have their limitations, however. I am interested in how lizard ecology changes through geologic time as preserved in the fossil record. This requires understanding the ecology of extinct lizards. For my thesis, I quantified ecology using stable isotope ratios in both living and extinct lizard species. Through my analyses, I was able to differentiate their diets and habitats. My examination of lizard fossils from ~54 million years ago identifies two lizards and one snake, and analyses of the fossil lizards indicate they were carnivorous or insectivorous and lived in a tropical climate. These stable isotope analyses not only have the potential to infer diet and habitat, but also track illegal pet trade and determine if an organism is warm or cold blooded.

Call number: LD2668 .T4 1979 A36 / Master of Science

Floodplains are among the most productive and biologically diverse freshwater ecosystems on earth. The exchange of nutrients and biota that occurs within these systems during seasonal inundation is essential in maintaining floodplain and river health. Anthropogenic structures, such as weirs, channels, and dams, have altered the natural flood hydrology of floodplain systems minimizing the frequency, strength and duration of flood events. This reduction ultimately leads to the isolation of important floodplain habitat, such as off-channel lakes, from the main channel, decreasing connectivity. Although some studies have examined the productivity of off-channel floodplain lakes in relation to connectivity, most are limited to tropical or highly degraded systems. Northern floodplains are not as well understood, with most of the research limited to the spring, summer, and fall seasons, when waterbodies are free of ice. With research limited to ice free seasons, there is not a full understanding of the year-round processes that occur within these off-channel lake habitats. This knowledge is crucial as the winter season is often when conditions within these habitats are at their most extreme. Such conditions prevent many fish species from permanent settlement; however, no research has been attempted to understand fish presence within these habitats during the winter season. In tropical systems, hypoxia-tolerant species and juveniles utilize these habitats as refuge from intolerant predators, so such habitat may be used similarly in more northern systems. The purpose of this research was to understand the connectivity, limnology and suitability as fish habitat of off-channel floodplain lakes in the Saskatchewan River Delta (SRD), SK, during winter months. I determined the degree of connectivity to the main channel for 26 individual lakes within the SRD by two modern methods: remote sensing imagery, and stable isotopes (δ18O, δ2H). Both of these techniques proved effective at determining connectivity of individual lakes and showed good agreement, with lakes arranged into five connectivity categories using remote sensing imagery. Winter limnological conditions within these lakes were significantly influenced by their degree of connectivity, with lakes that were more connected having characteristics similar to that of the river, with higher levels of dissolved oxygen (DO), nitrates (NO3-NO2), pH, and lower levels of nutrients (TN,TP). Lakes that were less connected were characterized by low levels of DO and nutrients, and high levels of ammonia/ammonium (NH3-NH4), conditions that are not favourable for the survival of many fish species. Some of the more hypoxia-tolerant species found within the SRD appear, however, to use these habitats in the winter. This was supported by detection of fish presence using environmental DNA; five fish species were detected in many of the 26 lakes sampled, but only in lakes with NH3-NH4 levels below 1.77 mg/L and volumes greater than 178000 m3. Together, these analyses suggest the influence of a spring/summer flood pulse on limnology is not limited to the months following a flood event, but rather extends well into the ice-cover season. This knowledge is critical as it points to controls on key processes (e.g. nutrient cycling, provision of fish habitat) during the period when lake conditions are most severe. As a result of human induced climate change, and from increased water demands for agriculture and hydropower, the natural flood pulse is expected to further decrease in size and frequency in large river-wetlands such as the SRD. This will reduce the connection between the floodplain and the main channel, with profound impacts on the SRD ecosystem as a whole. Lakes that currently experience frequent inundation will likely have conditions characteristic of infrequently flooded lakes, with low DO and nutrients and high NH3-NH4. Lakes which currently experience infrequent inundation will likely dry up completely due to decreased water renewal.

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No description available.