To see the other types of publications on this topic, follow the link: Stable and clumped isotope.
Dissertations / Theses on the topic 'Stable and clumped isotope'
Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles
Consult the top 50 dissertations / theses for your research on the topic 'Stable and clumped isotope.'
Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.
You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.
Browse dissertations / theses on a wide variety of disciplines and organise your bibliography correctly.
1
Methner, Katharina [Verfasser], Andreas [Gutachter] Mulch, and C. Page [Gutachter] Chamberlain. "Recovering Eocene paleotopography and paleoclimate of the North American Cordillera through integrated stable isotope and clumped isotope analyses / Katharina Methner ; Gutachter: Andreas Mulch, C. Page Chamberlain." Frankfurt am Main : Universitätsbibliothek Johann Christian Senckenberg, 2016. http://d-nb.info/1115250353/34.
Full text
2
Li, Shanying. "Petrological and stable isotopic study of lacustrine and paleosol carbonates: Implications for paleoelevation and tectonic evolution of the Tibetan Plateau." Miami University / OhioLINK, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=miami1461562459.
Full text
3
Peral, Marion. "Calibration of the clumped-isotope thermometer in foraminifera and its application to paleoclimatic reconstructions of the mid-Pleistocene in the Gulf of Taranto." Thesis, Université Paris-Saclay (ComUE), 2018. http://www.theses.fr/2018SACLS382/document.
Full textAbstract:
Quantifier les variations de température océanique du passé est nécessaire pour comprendre les mécanismes qui régissent l’évolution climatique. Les méthodes de paléo-thermométrie classiques peuvent souffrir de limitation inhérente à l’écologie des organismes et/ou à cause de l’influence d'effets physico-chimiques (salinité, acidité de l’eau de mer…). Ce travail se focalise sur la technique de paléothermométrie Δ47, qui repose sur la mesure du « clumping isotopique » dans les carbonates. Il vise d’abord à établir une calibration appliquée aux foraminifères et ensuite à mettre en œuvre cette calibration pour l’étude des variations climatiques au cours de la transition du Pléistocène moyen (MPT). Notre calibration Δ47-température des foraminifères planctoniques et benthiques, prélevés dans des sédiments modernes, couvre une gamme de température de -2 à 25°C. Les valeurs de Δ47 sur 9 espèces de foraminifères présentent une excellente corrélation avec la température de calcification des organismes, estimée à partir des mesures isotopiques de l’oxygène. Les résultats obtenus confirment l’absence d’effets liés à l’écologie des foraminifères (effets vitaux et de taille des organismes) et démontrent que la salinité n’affecte pas les mesures de Δ47. Cette étude constitue une avancée méthodologique importante pour les futures études paléocéanographiques sur les foraminifères. La MPT correspond à une transition climatique marquée par un changement de fréquence des cycles glaciaires-interglaciaires (de 41 000 à 100 000 ans). La compréhension de cette période est un enjeu scientifique majeur pour appréhender la mise en place du climat actuel. Notre calibration Δ47-température a permis de quantifier les variations de températures au cours de la MPT en mer méditerranée (Section de Montalbano Jonico, sud de l’Italie) et particulièrement des stades isotopiques marins 31 et 19, considérés comme des analogues à l’Holocène. Les résultats indiquent que (i) les températures (Δ47) obtenues sont en adéquation avec les températures obtenues par d’autres paléothermomètres, (2) les températures permettent de retracer les changements de régime océanographique et hydrologique, et (3) la mesure du Δ47 est complément prometteur pour les études multi-méthodes en paléocéanographieThe quantification of past oceanic temperature changes is a critical requirement for understanding the mechanisms which regulate climate variations. Classical methods of paleothermometry could suffer from well-known limitations related to ecology and/or to physico-chemical biases (sea water salinity, acidity…). This work focuses on clumped-isotope carbonate thermometry (Δ47). It aims to establish a calibration of Δ47 foraminifera and use it to study past climatic variations through the Mid-Pleistocene Transition (MPT). Our Δ47 calibration in planktonic and benthic foraminifera collected from modern marine sediment covers a temperature range of -2 to 25 °C. The clumped-isotope compositions of 9 species of foraminifera show a robust correlation with the calcification temperature, estimated from the measurements of oxygen-18. These results confirm the absence of bias linked to foraminifer ecology (species-specific and foraminifer size effects) and provide evidence that salinity does not affect the Δ47 thermometer. This study constitutes significant methodological progress for future paleoceanographic applications in foraminifera.The MPT is a climatic transition characterized by a shift in the frequencies of glacial-interglacial cycles (from 41 000 to 100 000 years). Understanding the MPT is a major scientific objective, which underlies our effort to study the establishment of our present climate. Our Δ47 calibration was used to quantify temperature changes through the MPT in the Mediterranea Sea (Montalbano Jonico section, south of Italy), and in particular the marine isotopic stages 31 and 19, which may be described as Holocene analogues. We find that (1) Δ47 temperatures are in good agreement with temperatures reconstructed from other paleothermometers, (2) these results allow reconstructing changes in past oceanographic and hydrologic regime, and (3) Δ47 measurement are a promising component of multi-proxy paleoceanographic studies
4
Guo, Weifu Blake Geoffrey A. Eiler John. "Carbonate clumped isotope thermometry : application to carbonaceous chondrites and effects of kinetic isotope fractionation /." Diss., Pasadena, Calif. : California Institute of Technology, 2009. http://resolver.caltech.edu/CaltechETD:etd-12182008-115035.
Full text
5
Kirk, Ruth. "Development of clumped isotope techniques and their application to palaeoclimate studies." Thesis, University of East Anglia, 2017. https://ueaeprints.uea.ac.uk/63690/.
Full textAbstract:
The aims of this research were to firstly help development of clumped isotope measurements of carbonate samples at UEA, and to then explore whether the technique could be used to retrieve robust environmental signals from geological material. This specifically looks at the Hirnantian glaciation at the boundary between the Ordovician and Silurian periods. Using the MIRA instrument, it is possible to make high precision measurements to enable the assessment of Earth surface temperatures. Long term precision of standard material is comparable to existing studies. MIRA is also absent of any non-linearity issues. Removal of contaminants and the identification of samples displaying contamination is stringent, as we find contamination has a serious effect on the Δ47 signal. Using modern biogenic carbonates and controlled temperature precipitates, the relationship between the clumped isotope signatures represented by the Δ47 value and temperature is: Δ47(ARF) = 3.5 x 10⁴/ T² + 0.2416. The relationship lies within measurement error of the theoretical estimate of temperature sensitivity. Applying this temperature calibration to fossil material collected from across the Ordovician/Silurian boundary found that the clumped isotope signal had been overprinted during diagenesis, and it has not been possible to extract an original Earth Surface temperature. However, the isotopic signal does show how the basin has developed during diagenesis under closed system conditions. As a result, the bulk δ¹⁸O and δ¹³C values have not been altered and record an original environmental signal.
6
Laycock, Adam John. "Stable isotope tracing of engineered nanoparticles." Thesis, Imperial College London, 2014. http://hdl.handle.net/10044/1/43853.
Full textAbstract:
Engineered nanoparticles (NPs) are increasingly being used in consumer products due to their novel properties. Consequently, concerns have been raised over the potential hazards that these materials may present as a result of their release into the natural environment. This has prompted numerous investigations into the environmental behavior, transport and fate of engineered NPs. Importantly the predicted environmental concentrations of these materials is often x10 to x100 lower than the natural background levels of the element. Many studies overcome this problem with the use of high dosing concentrations, however this raises concerns regarding environmental relevance. The work presented in this thesis demonstrates how stable isotope tracing enables the accurate detection and quantification of engineered NPs in complex biological samples even when exposures are performed at low and environmentally relevant concentrations. This thesis focuses on three of the most prominent commercially available NPs; ZnO, CeO2 and Ag, and covers all aspects of the application of stable isotope labeling and tracing for these materials. This includes; (i) an assessment and evaluation of the technique for application with CeO2 NPs, including the development of chemical separation and mass spectrometric methods for an environmental tracer study, (ii) the assessment of a synthesis protocol for the production of isotopically labeled Ag NPs, and (iii) two environmental tracer studies to assess the uptake and loss of Zn from ZnO NPs by an estuarine snail and earthworm.
7
Nelson, Michael Eric. "Nonactin biosynthesis : stable isotope precursor studies /." The Ohio State University, 2001. http://rave.ohiolink.edu/etdc/view?acc_num=osu1486399451962492.
Full text
8
FRANZOI, ALESSANDRO. "ANIMAL ECOLOGY THROUGH STABLE ISOTOPE ANALYSIS." Doctoral thesis, Università degli studi di Pavia, 2016. http://hdl.handle.net/11571/1203350.
Full textAbstract:
Stable Isotope Ratios techniques raised in the last thirty years as a novel approach very useful for researchers and ecologists that intend to deepen into manifold aspects of animal ecology. In particular, isotopic ratios in animal tissues ultimately reflect diet, and the isotopic composition of diet reflects biogeochemical attributes of environments that may, in turn, show spatial structure and pattern, both at local and continental scale.
Here, SIRs techniques were applied to birds, and, in particular, the stable isotope ratios of hydrogen, carbon, nitrogen, oxygen and sulfur were determined in bird feathers.
The study was articulated in three different case studies.
In the first two studies, SIRs technique was applied to migratory birds, sampled during post-breeding migration on Italian Alps. In particular, feathers were sampled on juvenile Passerines captured in some ringing stations of ‘Progetto Alpi’ long-term monitoring project. The focus was put both on commonly and less commonly observed species (more than 800 individuals of 48 species). The first study aimed to determine the geographical breeding origin of migrants using the stable isotope ratios of hydrogen and oxygen. The study allowed 1) to perform an analyses on the relationship between hydrogen and oxygen isotope ratios of several species, 2) to verify whether migratory populations have distinct geographical origins, different timing of passage and a comparison between species. To achieve the aims, a recovery data set was also used.
The second study focused on the application of stable isotope ratios of carbon, nitrogen and sulfur to infer the trophic attitudes of different passerine species during the breeding season. In this study more species were analyzed, aiming to understand if isotopic variability of carbon, nitrogen and sulfur were able to distinguish trophic relationships between species which have similar diets. It was found that species are isotopically different grouping them for migratory phenology.
These first two studies want to be a start point to better understand migrant trends across the Alps and Europe, and to improve knowledge in using stable isotopes in European continent.
The third case study focused on lesser kestrel breeding ecology in the Gela Plain, in Sicily. In particular the stable isotope ratios of hydrogen, carbon, nitrogen, oxygen and sulfur were measured in feathers of nestlings. The aim of this study was to delineate the isotopic fingerprint of the hunting areas of their parents, making possible to distinguish different spatial uses of adults within and between colonies, and verifying if different habitat selected may be translated into distinct isotopic composition in keratinous tissues. Findings underlined the potential that a multi-isotope approach has in studying animal ecology, especially in detecting trophic partitioning and habitat selection at local and regional scale.Stable Isotope Ratios techniques raised in the last thirty years as a novel approach very useful for researchers and ecologists that intend to deepen into manifold aspects of animal ecology. In particular, isotopic ratios in animal tissues ultimately reflect diet, and the isotopic composition of diet reflects biogeochemical attributes of environments that may, in turn, show spatial structure and pattern, both at local and continental scale. Here, SIRs techniques were applied to birds, and, in particular, the stable isotope ratios of hydrogen, carbon, nitrogen, oxygen and sulfur were determined in bird feathers. The study was articulated in three different case studies. In the first two studies, SIRs technique was applied to migratory birds, sampled during post-breeding migration on Italian Alps. In particular, feathers were sampled on juvenile Passerines captured in some ringing stations of ‘Progetto Alpi’ long-term monitoring project. The focus was put both on commonly and less commonly observed species (more than 800 individuals of 48 species). The first study aimed to determine the geographical breeding origin of migrants using the stable isotope ratios of hydrogen and oxygen. The study allowed 1) to perform an analyses on the relationship between hydrogen and oxygen isotope ratios of several species, 2) to verify whether migratory populations have distinct geographical origins, different timing of passage and a comparison between species. To achieve the aims, a recovery data set was also used. The second study focused on the application of stable isotope ratios of carbon, nitrogen and sulfur to infer the trophic attitudes of different passerine species during the breeding season. In this study more species were analyzed, aiming to understand if isotopic variability of carbon, nitrogen and sulfur were able to distinguish trophic relationships between species which have similar diets. It was found that species are isotopically different grouping them for migratory phenology. These first two studies want to be a start point to better understand migrant trends across the Alps and Europe, and to improve knowledge in using stable isotopes in European continent. The third case study focused on lesser kestrel breeding ecology in the Gela Plain, in Sicily. In particular the stable isotope ratios of hydrogen, carbon, nitrogen, oxygen and sulfur were measured in feathers of nestlings. The aim of this study was to delineate the isotopic fingerprint of the hunting areas of their parents, making possible to distinguish different spatial uses of adults within and between colonies, and verifying if different habitat selected may be translated into distinct isotopic composition in keratinous tissues. Findings underlined the potential that a multi-isotope approach has in studying animal ecology, especially in detecting trophic partitioning and habitat selection at local and regional scale.
9
Howland, Mark Roger. "Compound-specific stable isotope investigations of the influence of diet on the stable isotope composition of body tissues." Thesis, University of Bristol, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.274604.
Full text
10
Kaiser, Jan. "Stable isotope investigations of atmospheric nitrous oxide." [S.l. : s.n.], 2002. http://ArchiMeD.uni-mainz.de/pub/2003/0004/diss.pdf.
Full text
11
Morante, Richard. "Permian-Triassic stable isotope stratigraphy of Australia." Phd thesis, Australia : Macquarie University, 1996. http://hdl.handle.net/1959.14/47568.
Full textAbstract:
"September, 1995"Thesis (Ph.D.) -- Macquarie University, School of Earth Sciences, 1996.
Bibliography: leaves 171-183.
Introduction -- Australian ð¹³Corg-isotope profiles about the Permian-Triassic (P/TR) boundary -- Strontium isotope seawater curve in the late Permian of Australia -- ð¹³Cco₃ AND ð¹⁸Oco₃ seawater profiles through the Permian-Triassic of Australasia -- Paleomagnetic stratigraphy about the Permian/Triassic boundary in Australia -- Synthesis.
The Permian-Triassic boundary mass extinction is the largest in the Phanerozoic and therefore is the major event in the Phanerozoic. The mass extinction cause is problematical but studying global geochemical and geophysical signatures about the Permian-Triassic boundary can provide insights into the cause of the mass extinction. Global events about the Permian-Triassic boundary are marked by changes in: ð¹³C values of carbon ; ⁸⁷Sr/⁸⁶Sr in unaltered marine calcite ; magnetic polarity. -- This study aims to identify these features in the sedimentary record and to test the ca libration of the Australian biostratigraphical schemes to the global geological timescale. The following features are found in the Permian-Triassic sediments of Australia: a ð¹³Corg in Total Organic Carbon excursion in 12 marine and nonmarine sections from Northwest to Eastern Australia ; a ⁸⁷Sr/⁸⁶Sr minimum in a composite section mainly from the Bowen Basin ; a magnetic polarity reversal in the Cooper Basin, central Australia. The Australian sections are thus time correlated, as follows: The negative ð¹³Corg excursion indicates the Permian-Triassic boundary and occurs: 1) in Eastern and Central Australia at the change from coal measures to barren measures with red beds at the beginning of the Early Triassic coal gap; 2) in Northwest Australia about the boundary between the Hyland Bay Formation and the Mount Goodwin Formation in the Bonaparte Basin and at the boundary between the Hardman Formation and the Blina Shale in the Canning Basin. The base of the negative ð¹³Corg excursion lies at or near the base of the Protohaploxypinus microcorpuspalynological zone. The ⁸⁷Sr/⁸⁶Sr minimum determined about the Guadalupian/Ochoan stage boundary in North America is found in the Bowen Basin about the boundary between the Ingelara and Peawaddy Formations. The ð¹³Corg excursion in the Cooper Basin is near a magnetic reversal within the Permo-Triassic mixed superchron. The implications of these findings include: confirmation of the traditional placement of the Permian-Triassic boundary at the coal measures/barren measures with redbeds boundary in Eastern Australia ; the linking of the the Permian-Triassic boundary to a mass extinction of plant species on land and the beginning of the Triassic coal gap indicated by the Falcisporites Superzone base that is coincident with the negative ð¹³Corg excursion ; a mass extinction causal model that links the ⁸⁷Sr/⁸⁶Sr minimum determined about the Guadalupian/Ochoan stage boundary to a fall in sealevel that led to changing global environmental conditions. The model invokes greenhouse warming as a contributing cause of the mass extinction.
Mode of access: World Wide Web.
xii, 183 leaves ill., maps
12
Broadmeadow, Mark. "Stable carbon isotope discrimination in forest canopies." Thesis, University of Newcastle Upon Tyne, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.386693.
Full text
13
Volpe, Christopher Michael. "Stable chlorine isotope variations in the atmosphere /." Diss., Connect to a 24 p. preview or request complete full text in PDF format. Access restricted to UC campuses, 1998. http://wwwlib.umi.com/cr/ucsd/fullcit?p3035919.
Full text
14
Cooney, Katherine Suzanne. "A stable isotope investigation of precipitation nitrate." College Park, Md. : University of Maryland, 2005. http://hdl.handle.net/1903/3000.
Full textAbstract:
Thesis (M.S.) -- University of Maryland, College Park, 2005.Thesis research directed by: Dept. of Geology. Title from t.p. of PDF. Includes bibliographical references. Published by UMI Dissertation Services, Ann Arbor, Mich. Also available in paper.
15
Wombacher, Frank. "The stable isotope geochemistry and cosmochemistry of cadmium." [S.l. : s.n.], 2003. http://deposit.ddb.de/cgi-bin/dokserv?idn=967287685.
Full text
16
Martin, G. M. "Globigerina bulloides : Preservation state and stable isotope variation." Thesis, University of Canterbury. Geology, 2001. http://hdl.handle.net/10092/6806.
Full textAbstract:
A 'preservation index' has been developed that enables selective population sampling of the planktic foraminiferal species Globigerina bulloides for geochemical and isotopic analyses. Specimens from deep-sea core horizons were separated into 5 grades, based on the degree of transparency exhibited under the transmitted light microscope (grade 1 = thick-walled, non-transparent tests, to grade 5 = thin-walled, entirely transparent tests). 'Preservation indices' were then derived for a down-hole sequence of 23 samples from deep-sea core SO 136-005 (Eastern Tasman Sea, 958m). These indices indicate a general increase in dissolution downhole and significant variation in preservation between alternate sampled horizons. Fragmentation counts were made using the same samples and indicate increased fragmentation with depth. Analysis of δ18O showed a significant difference in concentration of that isotope (0.2 to 1.2‰) between grade 1 and grade 5 specimens (where usually, a divergence of >0.3‰ is considered significant).
The fact that it is possible to derive contrasting δ18O results from specimens of one foraminiferal species extracted from the same sample has far reaching implications for paleoceanography in general, and oxygen isotopic studies in particular. These results show that significant variation in δ18O signal can be entirely owing to preservation level. Collection of samples exhibiting the same preservation state, or systematic selection of the same number of specimens from different grades for all horizons in a sediment pile, should lead to increased accuracy with respect to the resultant oxygen isotope data for paleoceanography studies. In many cases, foram tests used in this study also exhibited a secondary calcite layer on the external surface. The fact that the remains of nannofossils were occasionally found submerged in the same layer is interpreted as a potential source of contamination of the primary oxygen isotope signal. The ease with which this secondary layer of calcite, on the exterior surfaces of foram tests, could be removed through acid etching was also examined. Foram tests were exposed to acetic acid solutions of pH 5.5-6.5 for differing exposure times and the effects of the acid on tests examined under the Scanning Electron Microscope. An optimum exposure time of 2 days at pH 5.5 was derived for total removal of the surface layer. A number of recommendations are made with regard to areas of future research resulting from the present study.
17
Reidy, Lisa Jayne. "Stable isotope analysis : a new forensic science tool." Thesis, Queen's University Belfast, 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.479310.
Full text
18
Ek, Caroline. "Towards understanding stable isotope signatures in stressed systems." Doctoral thesis, Stockholms universitet, Institutionen för miljövetenskap och analytisk kemi, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-134967.
Full textAbstract:
Stable isotope analysis (SIA) is a valuable tool in ecotoxicology because δ13C and δ15N may provide insights into the trophic transfer of contaminants in a food web. The relationship between a species’ trophic position (TP, determined from δ15N) and internal concentration of biomagnifying contaminants can be established and used for regulatory purposes. However, the exposure of organisms to xenobiotics incurs physiological costs, and the stable isotope signature of a consumer reflects not only diet but also a physiological state. The latter raises questions regarding the interpretation of stable isotope signatures in contaminated areas. Therefore, the aim of this Thesis was to evaluate the behaviour of consumers’ stable isotope signatures in stressed systems, with a primary focus on the effects of environmental contaminants. In paper I, the physiological costs of chemical exposure were found to alter incorporation rates of dietary nitrogen and carbon in a consumer by influencing both growth and metabolic turnover, with resulting changes in isotope signatures relative to a control system. In paper II, the diet-consumer discrimination factors for 15N and 13C were confirmed to increase under chemical exposure mediated via increased metabolic costs. However, the physiological response was low and translated into only minor shifts in the δ13C and δ15N. The predictability of exposure effects on the stable isotope signature was demonstrated in paper III, in which animals exposed to a chemical with a known mode of action presented expected effects on elemental composition, body size, biomarkers of oxidative stress and the stable isotope signatures. Moreover, consumers’ oxidative balance was found to be related to their δ15N values, thus providing evidence of the kinetic isotope effect on the oxidative status. However, despite the alterations in stable isotope signatures observed in laboratory settings (papers I-III), the effect of xenobiotics on the TP estimates was nil or minor in the field-collected animals. Moreover, the TP values were not significantly different between the animals in the contaminated and the reference habitats because of the high overall uncertainties in the TP estimates (paper IV). Also, the TP estimates based on δ15N in bulk material were more similar between the contaminated and the reference systems than TP estimates based on δ15N values in amino acids. Therefore, the latter method appears more sensitive towards xenobiotics (and, possibly, other environmental stressors) and thus less suitable for TP assessment in contaminated areas. This Thesis improved the overall understanding of the applicability of SIA in stressed systems by establishing relationships between various exposure regimes, physiological responses and the stable isotope signatures in consumers. In model species at low trophic levels, the exposure to xenobiotics was found to significantly affect δ13C and δ15N values, which can be expected whenever physiological responses are detected. However, because of the overall high uncertainty in TP estimates, no significant differences between contaminated and control systems were detected, although the estimated TP were consistently higher in the contaminated systems. Future research should focus on higher trophic levels, in which effects of a greater magnitude can be expected. Moreover, the effects in entire food webs should be addressed rather than single prey–consumer relationships as well as other environmental variables that may contribute to the stable isotope variability in and among systems under various environmental pressures.At the time of the doctoral defense, the following papers were unpublished and had a status as follows: Paper 3: Manuscript. Paper 4: Manuscript.
19
Diamond, Roger Edward. "Stable isotope hydrology of the Table Mountain group." Doctoral thesis, University of Cape Town, 2014. http://hdl.handle.net/11427/21190.
Full textAbstract:
Rain was collected from 2010 to 2012 at 15 locations around the Cape Fold Belt, at the same time as samples from rivers, springs, seeps and boreholes, totalling 435 samples. Precipitation ranged from -75 ‰ to +40 ‰ for δD and -12 ‰ to +8 ‰ for δ¹⁸O , showing seasonal patterns, with lower δ values in winter and higher in summer. Certain anomalous δ values can be attributed to individual weather events, such as thunderstorms. Using weighted data, the meteoric water line is δD = 6.15 δ¹⁸O + 8.21, which is similar to previous equations. The best fit line for groundwater δ values is δD = 7.09 δ¹⁸O + 10.08, the steeper gradient and higher intercept reflecting the predominance of heavy rainfall events with lower δ values in recharge, known as selection. The range of -47 ‰ to 0 ‰ for δD and -8 ‰ to -1 ‰ for δ¹⁸O values for all groundwater data is about half that of the rain values, due to the averaging effect from mixing during groundwater flow. Rainfall isotope composition is negatively correlated with continentality, as defined by the product of distance to the Atlantic and the closest coast. Isotope composition of rainfall is also strongly negatively correlated with altitude. Sites that are elevated within the landscape have a reduced altitude effect, such as tall peaks, whereas mountain valleys display enhanced altitude effects. Temporal and spatial variations in the strength of the amount effect reveal meteorological variability and emphasise the need for long term monitoring.
20
Dyer, David Clifford. "Stable isotope ecology of South African kelp forests." Doctoral thesis, University of Cape Town, 2018. http://hdl.handle.net/11427/29601.
Full textAbstract:
Kelp forests are some of the most productive coastal ecosystems in the world and provide numerous ecosystem goods and services. Where they occur, they play a key role in coastal ecology and local fisheries. In South Africa, Ecklonia maxima and Laminaria pallida form kelp forests which support diverse ecological communities. The species composition of these communities has been shown to be spatially variable along the South African coast, controlled by abiotic processes and species interactions. Despite their importance in the southern Benguela Current Large Marine Ecosystem (BCLME), large-scale research directed towards these habitats has largely waned over the past 30–40 years, prompting a renewed focus on these systems. Stable Isotope Analysis (SIA) is an indispensable tool for investigating food web characteristics, with particular focus on trophic structure and functioning. SIA can be used to understand the basal isotope variability in producers, determine the primary carbon sources of food webs, and investigate the spatial and temporal patterns in consumer isotope values and trophic niches. Unlike in other global kelp ecosystems, this methodology has not yet been applied to the kelp forests in South Africa. A study among eight geographically separate sites and two seasons highlights the natural variability of stable isotope values (δ13C and δ15N), at different spatial and temporal scales, within the two dominant kelp species. Additionally, stable isotope variability was investigated within and among different tissues within both kelp species. Within a kelp plant, δ13C values had a range of 1.65‰ for E. maxima and 1.52‰ for L. pallida. The δ15N values had a range of 3.75‰ for E. maxima and 4.21‰ for L. pallida. There were also consistent variability patterns along the length of a single frond in both species, for both isotopes. Among the localities, E. maxima and L. pallida were highly variable with ranges in δ13C (9.37‰ and 11.22‰) and δ15N (3.44‰ and 4.51‰) for the two species respectively. The δ13C values of L. pallida and E. maxima displayed a clear pattern coinciding with depth, particularly for L. pallida. Within-site variability was a major contributor to the overall spatial variability for both species. This provides further evidence for the importance of understanding basal variability of stable isotope values when determining the carbon sources of bottom-up controlled ecosystems. Variability in particulate organic matter (POM) composition is hypothesized to be related to upwelling processes in, and around, a typical west coast kelp forest. Various variables were used to characterise the composition, and determine the dynamics, of the POM along two transects (alongshore and off-shore) originating within a kelp forest. SIA was employed to estimate the contribution of kelp-derived detritus (KDD) to the POM present in the water column, using a unique approach for isolating phytoplankton and kelp end-member values. Under upwelling conditions, stable isotope analyses confirmed the dominance (>70%) of kelp detritus in POM samples, even at distances of 7.5 km off-shore. Under downwelling conditions, however, phytoplankton was dominant (>60%) along both transects. This study therefore highlights the importance of coastal processes such as upwelling for controlling the composition of POM in kelp forests, as well as illustrating how the natural variability in POM composition created by upwelling processes can be used to gather POM endmember isotope values. Three ecologically distinct kelp forest communities were investigated using a combination of SIA and community-wide niche metrics ('Layman metrics’ and Bayesian inferences). Three kelp forests, with differing community composition were selected, including a west coast kelp forest, a False Bay kelp forest and a lobster-invaded kelp forest located east of Cape Hangklip at Betty’s Bay. Temporal and spatial variability in stable isotope values was identified in producer and consumer stable isotope values, but was variable among species. Community-wide metrics showed clear seasonal patterns, but despite large differences in community structure, metrics were not vastly different among sites. Seasonal variability was the largest observable trend in metrics at all sites. Community niche areas showed a high degree of overlap (80–95%) further illustrating the similarity among sites and seasons. These findings are largely contrary to expected patterns from community composition data. Trophic position and isotope niche of the West Coast Rock Lobster (Jasus lalandii) was determined at three ecologically different kelp forest habitats, located in Marine Protected Areas in south-western South Africa. Temporal and spatial variability in trophic position and niche size were detected. The stable isotope niche and trophic position of lobsters at Betty’s Bay were markedly different from those at Oudekraal and Bordjiesrif, with the summer niche being distinct (0% overlap). Trophic position was lowest at the lobster-invaded Betty’s Bay (2.52) and highest at Bordjiesrif (3.16). Similarly, the isotope niche of Jasus lalandii was significantly constricted at Betty’s Bay compared to the other two study sites. Primarily, these results show that in the region where these lobsters have invaded, the trophic niche is considerably constricted. This likely to be a consequence of the higher densities of lobsters in this area. These findings highlight the influence of the lobster invasion on Jasus lalandii itself, adding to the already published ecological effects on the kelp forest ecosystem as a whole. These findings also highlight the differences in trophic niche of this species, despite the overall community niche showing little difference among sites. The findings of this thesis provide estimates of the variability in stable isotope values of kelp forest seaweeds and consumers, as well as addressing the importance of ocean processes such as upwelling in controlling POM composition in kelp forests. Additionally, the trophic niche of a key kelp forest predator was characterised in ecologically different kelp forests, providing evidence of the effect of community structure on the niche of this species. This is the first concerted research effort into the stable isotope ecology of South African kelp forests, providing an updated look at the ecology of these important ecosystems, and serves as a foundation for future studies of this type.
21
Young, Giles Hugh Findlay. "Stable isotope dendroclimatology at Forfjorddalen in northwestern Norway." Thesis, Swansea University, 2008. https://cronfa.swan.ac.uk/Record/cronfa42414.
Full textAbstract:
Climate change has become a key issue for the 21st century and producing future climatic scenarios has become a priority. However, to model future climate scenarios successfully and to understand their implications it is important to have a clear picture of past climate. Stable isotopes from tree rings may have the potential to reconstruct past climate at all temporal frequencies. This thesis presents a reconstruction of temperature (AD 1394- 2001) and precipitation (AD 1765-2001) from Forfjorddalen in northwest Norway based on and delta13C and delta18O, respectively. Tree cores were dated and the annual growth rings cut and extracted to alpha-cellulose, measurements of delta13C and delta18O and were then made. Corrected delta13C[pin] was calibrated with temperature (r = 0.71) and delta18O with precipitation (r = 0.57). A conceptual model of the relationship between delta13C and delta18O and temperature and precipitation is presented to explain a period of non-linearity in the relationship between delta13C and temperature. The delta13C temperature reconstruction suggests periods with warmer summer temperatures than the late twentieth century during the mid 18th and early 17th centuries; the coldest periods occur in the early 15th and late 19th centuries. This reconstruction compares favorably with long Scandinavian temperature records form Tornedalen (AD 1802) and Uppsala (AD 1722) and a recent tree-ring density based reconstruction from Tornetrask. It also exhibits much greater multi-decadal variability than the previous, ring-width based, Forfjorddalen temperature reconstruction. A precipitation reconstruction (AD 1765 to 2001) shows wet conditions during the late 18th and early 19th centuries followed by a dry period in the late 19th century, becoming wetter again through the 20th century. Spatial field correlations demonstrate the potential for proxy data from Forfjorddalen to reconstruct climate on a regional scale; combination with data from Tornetrask yields correlations > r=0.70 with much of northwestern Scandinavian temperature.
22
Kim, Moon Koo. "Stable carbon isotope ratio of polycyclic aromatic hydrocarbons (PAHs) in the environment: validation of isolation and stable carbon isotope analysis methods." Diss., Texas A&M University, 2004. http://hdl.handle.net/1969.1/1099.
Full textAbstract:
Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous, toxic contaminants that are released to the environment from various petrogenic and pyrogenic sources. In an effort to more clearly identify and trace sources of PAHs in the environment, purification and compound specific isotope analysis methods were developed to accurately measure the stable carbon isotope ratio of individual PAHs. Development of the method included improving accuracy and precision of the isotopic measurement by producing highly pure extracts using various chromatographic techniques. The method was refined by improving compound separations using purification techniques and high resolution chromatographic columns. The purification method consists of alumina/silica gel column chromatography, gel permeation chromatography and thin layer chromatography. The mean recovery of PAHs after the purification procedure was approximately 80 %. Sample purities after purification were verified by GC/FID and full scan mass spectrometry. To better resolve peaks and provide more accurate stable carbon isotope measurements, various gas chromatographic conditions were evaluated. The precision of the method ranged between 0.08 and 0.43 . The analytical protocols were evaluated to confirm compositional and stable isotopic integrity during purification and stable isotopic analysis. To confirm the utility of the purification and isotope analysis methods, various environmental samples from marine, land and lacustrine environments were analyzed. The isolates were analyzed for the composition and the stable carbon isotope ratios of PAHs. The stable carbon isotope ratio was measured by GC/IRMS and the results, along with quantitative compound compositions, were used to characterize and identify the contaminant sources. The sources of the PAHs in the study areas were differentiated by PAH molecular ratios and confirmed by stable carbon isotope ratios. This study confirms that compound specific isotope analysis of pollutants by GC/IRMS can be used to identify PAH sources in environmental samples. The study also confirms that the purification and stable carbon isotope analysis methods that were developed can be used to accurately measure the stable carbon isotope ratios of PAHs in environmental samples for the purpose of source identification. GC/IRMS measurement of stable isotopic compositions can be an effective fingerprinting method when used in conjunction with traditional molecular composition methods.
23
Strand, Sarah Elise. "Stable Isotope Biogeochemistry of South Florida Coastal Marine Ecosystems." FIU Digital Commons, 2014. http://digitalcommons.fiu.edu/etd/1737.
Full textAbstract:
Southeast Florida’s continual urban expansion will potentially increase anthropogenic pollution in adjacent coastal marine systems. Furthermore, increased nutrient loads could have detrimental effects on the already threatened Florida Reef Tract. The present study uses a stable isotopic approach to determine the sources and the impact of nutrients on the Florida Reef Tract. δ13C and δ15N analysis of macroalgae, sponges, and sediment were analyzed in order to determine nutrient inputs in this region. While δ13C data did not display any significant trends spatially, δ15N values of the majority of biota exhibited a strong East to West gradient with more enriched values close to shore. Relative enrichment in δ15N values were measured for sediments sampled along the Florida Reef Tract in comparison to a pristine Marquesas Keys sediment core. The δ15N data also implies that shoreline anthropogenic nutrients have more nutrient loading implications on reefs than major point sources.
24
Addison, Sarah Louise. "15N stable isotope probing of pulp and paper wastewaters." The University of Waikato, 2008. http://hdl.handle.net/10289/2399.
Full textAbstract:
Stable isotope probing (SIP) is an established technique that can be applied to identify the metabolically active micro-organisms within a microbial population. The SIP method utilises an isotopically-labelled substrate and PCR techniques to discern the members of a microbial community that incorporate the isotope into their DNA or RNA. The current literature gap around using 15N isotopes with RNA-SIP offers real potential and advantages for targeting and identifying active members from mixed communities involved in global biogeochemical nitrogen cycling. This study specifically investigated whether nitrogen based compounds can be used as substrates in RNA-SIP methodologies and whether they can in turn be used to probe mixed community environments known to be actively fixing nitrogen. The nitrogen-limited systems targeted represented an ideal opportunity to assess the suitability of 15N-RNA-SIP approaches due to their known high nitrogen fixation rates. Identifying these nitrogen-fixing bacteria could provide a better representation analysis of the community, leading to an improved prediction on how to manage and optimise the treatment performance of target waste systems and to exploit the unique bioconversion properties of these types of organisms. Initially, the project undertook methodological proof of concept by using a soluble nitrogen source, 15NH4Cl, to label the RNA of Novosphingobium nitrogenifigens and a mixed microbial community. Successful separation of the 14N- (control) and 15N-RNA was achieved for both pure and mixed communities using isopycnic caesium trifluoroacetate (CsTFA) gradients in an ultracentrifuge. The usefulness of this technique to identify active diazotrophs in real environmental samples was tested using a nitrogen-fixing community from a pulp and paper wastewater treatment system. After growing the mixed culture with 15N2 as the sole nitrogen source, the labelled RNA was extracted and fractionated using isopycnic centrifugation in CsTFA gradients. The community composition of the active nitrogen-fixing community in the 15N2 enriched fraction was analysed by establishing a 16S rRNA gene clone library containing over 200 members. These were analysed by comparison with published sequences and by phylogenetic analysis. It was found that the more isotopic label substrate incorporated, the further the buoyant density (BD) separation between 15N- and 14N-RNA. Novosphingobium nitrogenifigens gave an average BD shift of 0.03 + 0.004 g ml-1 (95.0 atom % 15N) with 15NH4Cl. For mixed communities the average BD shift was 0.02 + 0.004 g ml-1 (80.0 atom % 15N) with 15NH4Cl and 0.013 + 0.002 g ml-1 (32.6 atom % 15N) when using 15N2. Clone library analysis of 16S rRNA genes present in the enriched 15N-RNA fraction of the mixed community was shown to consist of a diverse population of bacteria as indicated by a Shannon Weaver index value of gt;2.8. Three dominant genera (Aeromonas, Pseudomonas and Bacillus) were identified by comparison with published sequences and phylogenetic analysis. Many other groups not known as archetypal nitrogen-fixing bacteria were also identified, demonstrating that 15N2-RNA-SIP provides a useful tool for the identification of important and previously unknown contributors to nitrogen fixation in a range of environments. Overall, this project has established that nitrogen based RNA-SIP is a powerful tool that can be used successfully and reproducibly with both pure and complex mixed microbial communities to study active diazotrophs in environmental samples.
25
Lock, C. M. "Stable isotope profiling of energetic materials and their precursors." Thesis, Queen's University Belfast, 2010. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.517100.
Full text
26
Izzard, A. "Studies of vitamin C economy by stable isotope probes." Thesis, University of Cambridge, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.604981.
Full textAbstract:
The aim of the work described in this thesis was to evaluate the potential for using stable isotope 13C labelled tracer, 1-13C -AA, in studies of AA kinetics in humans. To this end a method of measuring AA isotope enrichment in plasma samples using gas chromatography and mass spectrometry, (GC/MS), was developed. Derivatisation of AA was required for gas chromatographic separation, and the trimethylsilyl, (TMS), ether derivative, AA-tetra-TMS, was found to be the most compatible with subsequent mass spectrometric quantitation of isotope enrichment. A method was developed to prepare lyophilized plasma samples for TMS derivatisation. Two studies of AA kinetics in human volunteers were than carried out in which a dose of stable isotope labelled 1-13C-AA was administered orally. The enrichment of AA was measured in plasma samples collected for 24 and 48 hours after dosing. In the second study, investigation of isoascorbic acid, (IAA), kinetics was also undertaken. IAA concentration in plasma samples was measured by high performance liquid chromatography, HPLC. Compartment models of AA and IAA handling in man were constructed and described as a series of mathematical expressions containing kinetic parameters. Kinetic analysis was achieved by fitting theoretical values calculated from the mathematical expressions describing the models to the observed (time course) data. This produced estimates of kinetic parameters, (flow constants and pool sizes), describing AA and IAA handing in man. These were compared with those obtained in other studies. The method is now being applied to further studies into the bioavailability, metabolism and utilization of AA in humans and has the potential to be a useful non-invasive technique which may provide an invaluable insight into the vitamin C status of individuals in a variety of populations.
27
Hall, James Andrew. "Stable isotope methods for monitoring bioremediation of contaminated land." Thesis, Queen's University Belfast, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.322955.
Full text
28
Vohra, Jyotsna. "Stable isotope probing : a tool in molecular microbial ecology." Thesis, University of Warwick, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.443622.
Full text
29
MacDonald, Joanne. "Microstructure, crystallography and stable isotope composition of Crassostrea gigas." Thesis, University of Glasgow, 2011. http://theses.gla.ac.uk/2939/.
Full textAbstract:
Many marine molluscs produce complex shells of calcium carbonate. These shells are formed under strict biological control to provide a range of functions to ensure the survival of the living organism. These inspiring biomineral structures can also provide an archive of environmental change via proxies such as δ18O and δ13C within the shell carbonate. However, the intimate relationship between the biological and environmental controls influencing biomineral production can often obscure the environmental signal, making it difficult to interpret environmental information from shell proxies. Understanding the design of biomineral structures will further our knowledge of biomineralisation as a whole, while understanding the controls that influence shell production will ensure that shell proxies applied to palaeoenvironmental studies are accurate. Oysters are sessile bivalve molluscs that have evolved since the Triassic and expanded to occupy a range of habitats with almost global distribution, providing an example of a highly successful biomineral system. This study investigates the ultrastructure, crystallography and stable isotope composition of the Pacific oyster, Crassostrea gigas from estuarine and marine environments. The method by which oysters adhere to hard substrates is also investigated. Both valves of the oyster shell are composed predominantly of low Mg calcite in three forms; an outer prismatic region, an inner foliated structure and chalk lenses which appear sporadically throughout the valves. Aragonite is restricted to the myostracum and parts of the hinge structure. Crystallographic analysis shows that, despite variations in structural morphology, the superimposed layers of the oyster shell maintain a single crystallographic orientation with the crystallographic c-axis orientated perpendicular to the outer shell surface. Varying crystal morphology, while maintaining crystallographic unity, may be a deliberate design to provide the oyster shell with both strength and flexibility. In general, there is no difference in the overall ultrastructure or microstructural arrangement of estuarine and marine oysters. Estuarine oysters contain significantly more chalk than marine equivalents suggesting that the appearance of chalk lenses is, to some degree, triggered by an external environmental stimulus. Stable carbon and oxygen isotope analysis of folia and chalk provides further insights into the appearance of chalk in the oyster shell structure. There is no significant difference in the isotope composition of folia or chalky layers, although patterns of δ13C and δ18O of folia and chalk reveal key differences between the two structures. Folia display a narrower range of δ18O values compared with chalk and exhibit significant interspecimen variation with respect to δ13C. Interspecimen variation, with respect to either δ18O or δ13C is absent in chalk samples. These patterns suggest that secretion of folia requires a more specific environmental stimulus and a greater input of metabolic carbon than chalk. Chalk is apparently secreted across a greater range of environmental conditions, with less metabolic regulation. Deviation from optimal environmental conditions, for example during periods of reduced salinity and/or cold or warm temperatures, may reduce metabolism causing the oyster to deliberately default from folia to chalk secretion. In general, folia and chalk in both estuarine and marine oysters is secreted in oxygen isotope equilibrium with the ambient environment. Another aspect of the oyster biomineral system is their ability to adhere tightly, and usually permanently, to a range of hard substrates by cementation of the left valve. Investigation of the contact zone between oyster shells and biological (other oyster shells) and inorganic (rock) substrates reveals the influence of both biogenic and non-biogenic processes in oyster cementation. Original adhesion is brought about by secretion of an organic adhesive which acts as a nucleating surface onto which crystals precipitate which have random orientation and are composed of high Mg calcite. The lack of orientation and elevated Mg content suggests that these crystals are nucleating outwith the biological control experienced by the shell biomineralisation process and are formed from inorganic precipitation from seawater. It is proposed that oysters do not control, or secrete, the crystalline cement but instead they secrete an organic film onto which crystals precipitate from seawater. Oysters thus provide excellent examples of both biologically induced and biologically controlled mineralisation.
30
Stevenson, Emily Isabel. "Stable strontium isotope fractionation in marine and terrestrial environments." Thesis, University of Oxford, 2012. http://ora.ox.ac.uk/objects/uuid:a2d97fc7-3e9d-484a-8026-11c118fcc3fd.
Full textAbstract:
The work reported in this thesis applies a new isotope tracer, stable strontium isotopes (δ88/86Sr), to address questions concerning changes in global climate that occur in response to continental weathering processes, and to constrain the modern marine geochemical Sr cycle. Stable Sr isotopes are a relatively new geochemical proxy, and as such their behavior needs to be understood in differing forms of marine calcium carbonate, the archives from which records of past stable Sr variability in the oceans can be constructed. Foraminifera, coccoliths and corals (both aragonite and high Mg calcite) acquire δ88/86Sr values lighter than that of modern day seawater, (approximately 0.11, 0.05, 0.2 and 0.19 ‰ lighter than seawater at ~25°C respectively) providing a measureable offset which can be used to constrain the modern Sr outputs from the ocean and provide a better understanding of the modern Sr cycle. Using foraminifera as a sedimentary archive the first marine δ88/86Sr record of seawater over the last two glacial cycles has been constructed, and used to investigate changing carbonate input and output over this 145 kyr period. Modelling of the large excursion of δ88/86Sr to heavier values during Marine Isotope Stage (MIS) 3, reveals that this is more likely to be due to local changes in seawater or post-depositional alteration, rather then whole ocean changes. In the terrestrial environment δδ88/86Sr has been measured in the dissolved load of rivers from the Himalaya. It is found that, in general, rivers draining carbonate catchments possess lighter isotopic δ88/86Sr values than those from rivers draining silicates. Covariations of either δ88/86Sr vs. δ30Si or δ88/86Sr vs. 1/[Sr] can be used to distinguish between rivers draining different catchment areas.
31
Oskam, Charlotte. "Ancient DNA & stable isotope profiling of fossil eggshell." Thesis, Oskam, Charlotte (2012) Ancient DNA & stable isotope profiling of fossil eggshell. PhD thesis, Murdoch University, 2012. https://researchrepository.murdoch.edu.au/id/eprint/12744/.
Full textAbstract:
Eggshell is frequently encountered within palaeontological and archaeological deposits and due to various chemical and physical properties, it is highly valued as a substrate for geochronology, palaeodietary and palaeoecological applications. Despite the wellrecognised preservation of biomolecules in fossil eggshell, the substrate had never been evaluated for ancient DNA (aDNA) preservation. Herein, this thesis describes the first exploration involving the recovery and characterisation of aDNA from fossil eggshell. The primary aim of this thesis research is to explore eggshell aDNA and how genetic data, when combined with stable isotope profiles, provides new insights into hunting practices, zooarchaeology, palaeodiets, palaeobiology and extinction processes.
The visualisation of fluorescently-stained DNA in fossil eggshell by confocal microscopy revealed that genetic material was present in the eggshell of the extinct New Zealand moa (Aves: Dinornithiformes) and Madagascan elephant bird (Aves: Aepyornithiformes). The immediate task was to determine how to go about characterising the aDNA encapsulated in this previously unrecognised substrate. Quantitative PCR assays were employed to thoroughly evaluate different methods to maximise the recovery and amplification of aDNA from powdered eggshell. This study resulted in the successful characterisation of both mitochondrial and nuclear DNA isolated from 19,000 year-old emu eggshell and the first ever DNA sequence from the elephant bird, Aepyornis. All data pointed toward fossil eggshell as a reliable source of relatively pure aDNA. This work culminated in a formal description of the methodology that should be employed to maximise recovery of aDNA from eggshell.
Next, this thesis investigates whether eggshell aDNA could be applied to ‘first-contact’ archaeological sites in New Zealand, to gain new insights into the Moa-hunter period of prehistory. The abundance of moa eggshell within the ‘first-contact’ Polynesian archaeological sites is well recognised from previous excavations. With nine species of moa contained within the New Zealand archipelago however, the scientific value of these remains has been limited by the lack of definitive species assignments. Genetic species assignments of moa eggshell combined with morphological identification of bone (literature and museum catalogued specimens) has enabled the most comprehensive audit of zooarchaeology assemblages from several significant 13th-15th century AD deposits. In total, mitochondrial DNA (mtDNA) was amplified from 251 of 323 (78 %) eggshell fragments and 22 of 27 (88 %) bone samples, and the analyses revealed the presence of four moa species: Anomalopteryx didiformis; Dinornis robustus; Emeus crassus; and Euryapteryx curtus. The mtDNA, together with highly polymorphic microsatellite markers, were used in combination to individualise eggshell fragments. These data revealed over 50 individual eggs from Wairau Bar – a number that likely represents a considerable proportion of the total reproductive output of moa in the area. This emphasises that human predation of all life stages of moa was intense. In addition, an excess of male bones at the Wairau Bar site (determined by molecular sexing) suggests that males might have been preferential targets, perhaps while incubating eggs.
Lastly, moa eggshell genetics and stable isotope profiles were combined to examine the palaeodiets, palaeobiology, palaeoecology and the human mediated extinction of the moa. Organic (δ13Corg and δ15N) and carbonate (δ13Ccarb and δ18O) stable isotope profiles were analysed from 247 genetically identified eggshell fragments. The combination of ancient DNA and stable isotope profiles revealed moa consumed a diet consisting exclusively of C3 vegetation and occupied the varied landscape that surrounded the archaeological deposits. Given that moa were foraging in such diverse landscapes suggests that the first colonisers hunted these moa away from the homogenous landscapes immediately surrounding these archaeological sites and thus engaged in ‘central point foraging’. Discriminant functional analyses indicate moa eggshells can be assigned with good precision to their parent species based purely on their stable isotope profiles.
In conclusion, this thesis research has revealed a ‘new’ aDNA substrate that has a number of useful applications in archaeology, palaeogenomics and palaeoecology. The research on New Zealand moa eggshell demonstrated, first-hand, how this substrate can provide valuable insights into the biology, ecology and extinction of a megafaunal species. It is hoped the research will have a lasting influence on eggshell discovered across the globe.
32
Anchukaitis, Kevin John. "A Stable Isotope Approach to Neotropical Cloud Forest Paleoclimatology." Diss., The University of Arizona, 2007. http://hdl.handle.net/10150/195637.
Full textAbstract:
Many tropical trees do not form reliable annual growth rings, making it a challenge to develop tree-ring width chronologies for application to paleoclimatology in these regions. Here, I seek to establish high-resolution proxy climate records from trees without rings from the Monteverde Cloud Forest in Costa Rica using stable isotope dendroclimatology. Neotropical cloud forest ecosystems are associated with a relatively narrow range of geographic and hydroclimatic conditions, and are potentially sensitive to climate variability and change at time scales from annual to centennial and longer. My approach takes advantage of seasonal changes in the d18O of water sources used by trees over a year, a signature that is imparted to the radial growth and provides the necessary chronological control. A rapid wood extraction technique is evaluated and found to produce cellulose with d18O values indistinguishable from conventional approaches, although its application to radiocarbon requires a statistical correction. Analyses of plantation-grown Ocotea tenera reveal coherent annual d18O cycles up to 9 permil. The width of these cycles corresponds to observed basal growth increments. Interannual variability in d18O at this site is correlated with wet season precipitation anomalies. At higher elevations within the orographic cloud bank, year-to-year changes in the amplitude of oxygen isotope cycles show a relationship with dry season climate. Longer d18O chronologies from mature Pouteria (Sapotacae) reveal that dry season hydroclimatology is controlled at interannual time scales by variability in the eastern equatorial Pacific (ENSO) and the Western Hemisphere Warm Pool (WHWP), which are correlated with trade wind strength and local air temperature. A change in the late 1960s toward enhanced annual d18O amplitude may reflect low frequency changes in the Atlantic and Pacific ocean-atmosphere system. This study establishes the basis for cloud forest isotope dendroclimatology and demonstrates that the local climate of neotropical cloud forests is sensitive to interannual, and perhaps, multidecadal changes in important large-scale modes of climate variability.
33
Keck, Lothar. "Climate significance of stable isotope records from Alpine ice cores." [S.l. : s.n.], 2001. http://deposit.ddb.de/cgi-bin/dokserv?idn=963598708.
Full text
34
Guiry, Eric. "Tracing colonial animal trade and husbandry using stable isotope analyses." Thesis, University of British Columbia, 2016. http://hdl.handle.net/2429/59276.
Full textAbstract:
Domestic animals, particularly cattle and pigs, were a cornerstone of European colonial projects around the globe (ca. 1500-1900 AD). Livestock husbandry and trade provided not only a source of food, labour, and raw materials for daily life, but also held symbolic significance as a factor in establishing colonial group identity. This dissertation uses stable isotope analyses to reconstruct domestic animal trade and husbandry practices associated with the global expansion of European colonial activities into the New World between the seventeenth and nineteenth centuries. Research has been divided into three standalone projects, each designed to make a significant contribution to the current literature in the field of isotopic-zooarchaeological analyses. These projects are unified through a common theme of exploring the social roles of animal husbandry and trade and, together, provide a cohesive demonstration of how historical and isotopic faunal records can be integrated to advance archaeological interpretations of human-animal interactions. Paper 1 presents the first stable carbon, nitrogen, and sulfur isotope study of faunal remains from the unique archaeological context of a shipwreck (the William Salthouse, sunk in 1841), which provides an outstanding opportunity to assess how faunal isotopic patterns at archaeological consumption sites would be influenced by inclusion of animal products acquired through long-distance transportation. Paper 2 presents a stable carbon and nitrogen isotope study of domestic livestock and meat trade in nineteenth-century Upper Canada (now Ontario). This is the first large-scale isotopic analysis of historical faunal remains in North America and shows how consumption of foreign and local animal products can be linked with different groups of people to reveal social dimensions of meat trade in urban settings. Paper 3 presents stable carbon and nitrogen analyses of faunal remains for the seventeenth-century shipwreck La Belle, associated with La Salle’s famous attempt to colonize the mouth of the Mississippi River. This study reconstructs pig husbandry practices in the context of detailed firsthand historical accounts to show that for La Salle’s colonists, domestic animal husbandry likely reflected significant cultural importance, rather than economic and subsistence factors.Arts, Faculty of
Anthropology, Department of
Graduate
35
Cooper, Catherine Grace. "Exploring human dietary variation through stable isotope analysis of hair." Thesis, University of British Columbia, 2017. http://hdl.handle.net/2429/61210.
Full textAbstract:
This thesis explores the use of carbon, nitrogen and sulphur stable isotope analysis of modern and archaeological human hair as an indicator of human diets. The thesis is focused around three distinct research projects, two on modern, living humans and one on an archaeological population.
The first project focuses on dietary variation among different populations in modern Ethiopia that share the same resource base but follow different economic and subsistence patterns. This research shows that economic and cultural patterns can cause very distinct and significant differences in diet among populations with access to the same resources. The second project uses data from modern Nicaraguan villagers to explore variability in isotopic signatures among demographic groups within one population. The data reveal significant differences among demographic groups, but the absolute differences are quite small, indicating that it is necessary to have a large sample size to determine isotopic differences within a population. The third project is an archaeological case study presenting the first serial isotopic analysis of human hair from the Basketmaker II (BMII) midden at the site of Turkey Pen Ruins on Cedar Mesa, in south-eastern Utah. These data show potential seasonality of diet at the site, with variations in the amount of C₄ protein being contributed to the diet.
Together these projects contribute to our understanding of how different scales of dietary variation can be interpreted and approached through isotopic analysis of human hair. The studies also show the applicability of both intra-individual and inter-individual isotopic analysis of human hair to our understanding of modern and ancient diets.Arts, Faculty of
Anthropology, Department of
Graduate
36
North, Jessica C., and n/a. "Stable isotope tracers of landfill leachate impacts on aquatic systems." University of Otago. Department of Chemistry, 2006. http://adt.otago.ac.nz./public/adt-NZDU20070504.144317.
Full textAbstract:
The present study aimed to determine whether stable isotope techniques can be universally applied to detect landfill leachate contamination in aquatic systems. Results of analysis of ��C in dissolved inorganic carbon ([delta]��C-DIC), deuterium and �⁸O in water ([delta]D-H₂O and [delta]�⁸O-H₂O), and �⁵N of dissolved inorganic nitrogen components ([delta]�⁵N-NH₄⁺ and [delta]�⁵N-NO₃⁻) were presented for leachate, surface, and ground water samples collected from seven landfills located throughout New Zealand between 2003 and 2006. The unique conditions within a landfill lead to measurable fractionations in the isotopic ratios of the products of degradation. Results of isotope and ancillary parameter analyses enabled the discernment of different types of leachate, resulting from different microbial processes within the landfill environment. The isotopic characterisation of leachate enabled improved interpretation of geochemical data from potentially impacted surface and ground waters, and provides useful insight to landfill development for landfill operators. A general isotopic fingerprint delineated by [delta]��C-DIC and [delta]D-H₂O values showed leachate to be isotopically distinct from uncontaminated surface and ground water for samples analysed in the present study. However, not all water samples identified as leachate-impacted via site-specific assessments exhibited isotopic values that overlapped with the general leachate fingerprint. This highlights the need to investigate each site individually, within the context of a possibly global leachate isotope signature. Site-specific investigations revealed the effectiveness of applying [delta]�⁸O-H₂O and [delta]�⁵N-NH₄⁺ or [delta]�⁵N-NO₃⁻, in addition to [delta]��C-DIC and [delta]D-H₂O analyses, to the detection of leachate impact on aquatic systems. Furthermore, ancillary parameters such as alkalinity and ammonium concentration enabled the construction of simple isotope mixing models for an estimate of the quantity of leachate contribution. Results of isotopic investigations of stream biota suggested potential for the development of bio-indicators to monitor leachate influence on aquatic ecosystems in landfill-associated streams. The present study demonstrated the probative power of stable isotope techniques applied to investigations of leachate impact on landfill-associated aquatic systems.
37
Benbow, Timothy J., and n/a. "Developing compound-specific stable isotope tools for monitoring landfill leachate." University of Otago. Department of Chemistry, 2008. http://adt.otago.ac.nz./public/adt-NZDU20080314.111826.
Full textAbstract:
This thesis has developed a suite of compound specific stable isotope tools to monitor landfill leachate and identify the infiltration of leachate to ground water and surface water. These tools have the power to indicate the fractional contribution multiple discrete sources of pollution are making to a single location. This journey began by developing two solid phase extraction (SPE) methods to extract non-polar and polar organic compounds from leachate with minimal fractionation of hydrogen or carbon isotopes. Non-polar compounds were successfully extracted using ENV+ SPE cartridges and polar compounds were successfully extracted using Strata-X SPE cartridges. The isotopic fractionation of non-polar compounds during ENV+ extraction varied significantly (up to 245⁰/₀₀ and 1.8⁰/₀₀ for D and ��C respectively, when eluted with acetonitrile and ethyl acetate, as recommended by manufacturers) but the fractionation of compounds eluted with dichloromethane was negligible (less than instrumental precision). Polar compounds were eluted from Strata-X cartridges with negligible isotopic fractionation using methanol. The direct comparison of SPE and liquid-liquid extraction found SPE to extract slightly more compound from leachate then liquid-liquid extraction (especially for polar compounds) and the isotopic compositions of compounds did not change with extraction methods.
These new analytical methods subsequently were used to determine the isotopic compositions of organic compounds dissolved in leachates from three New Zealand landfills. The molecular and isotopic signature of leachate varied significantly between landfills, indicating the isotopic fingerprint of organic compounds in leachate is unsuitable as a universal tracer of leachate. However, compounds such as terpien-4-ol, methylethylbenzene and juvabione maintained their isotopic composition over short geographical distance-indicating their potential as site-specific tracers of leachate. Organic compounds analysed on a transect across the landfill boundary indicated polar compounds were more mobile than semi-volatile compounds and possessed a more conservative isotopic composition. However, hexadecanoic acid extracted from leachate and ground water was highly depleted in ��C (-72 ⁰/₀₀ to -40⁰/₀₀), indicative of methanogenic and sulfate reducing bacteria. These bacteria only live in highly reducing environments such as leachate; therefore their presence in the pristine environment can potentially indicate the release of leachate from the landfill.
The final experiments traced the uptake and utilisation of leachate by periphyton. The isotopic composition of bulk periphyton, fatty acids and phytol indicated that microbial assimilation and utilisation of nutrients is a complex process. Fatty acid biomarkers for green algae and diatoms showed signs of leachate derived nutrients, however the availability of nutrients (carbon, nitrogen, water and light) caused significant changes in metabolic processes and isotopic compositions. Under slow growing conditions, the [delta]��C composition of periphyton became enriched in ��C as solar irradiation levels decreased (including shading by detritus and periphyton), while the [delta]D composition of fatty acid was controlled by the internal recycling of hydrogen. This study indicated the power of compound specific isotope analysis as a tool to detect the release of landfill leachate from a landfill, especially at locations with multiple potential sources of contaminants, and provides a sound platform for future research.
38
Eimers, M. Catherine. "A stable isotope approach to investigate cadmium bioavailability from sediment." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk2/tape17/PQDD_0010/MQ30212.pdf.
Full text
39
Eek, Magnus. "Environmental control of stable carbon isotope systematics in Emiliania huxleyi." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape2/PQDD_0017/NQ52759.pdf.
Full text
40
Brown, Andrea J. "Endogenous decay sustaining PCE degradation and associated stable isotope effects." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape4/PQDD_0018/MQ53370.pdf.
Full text
41
Bedaso, Zelalem K. "Stable Isotope Studies of Paleoenvironment and Paleoclimate from Afar, Ethiopia." Scholar Commons, 2011. http://scholarcommons.usf.edu/etd/3004.
Full textAbstract:
ABSTRACT
The sedimentary deposits of the Hadar Formation at Dikika and the Mount Galili Formation at Galili preserve a wealth of paleoenvironmental and paleoclimatic records spanning the last 5.29 Ma. Stable carbon and oxygen isotopic compositions of herbivore tooth enamel were analyzed for more than 600 specimens of 15 different taxa from 10 stratigraphic intervals. The application of carbon and oxygen isotopes here aims
principally at reconstructing shifts in the relative abundance of C4 grasses, and its implications for climate indicators including temperature, aridity, and seasonality. The full range of δ13Cenamel values throughout the Plio-Pleistocene signifies a wide range of foraging strategies by the fauna, which in turn reflects the mosaic of vegetation at Dikika and Galili. Estimates of ecosystem carbon isotope composition (δ13Cecosystem , which is given by average δ13Cenamel of each large vertebrate taxon weighted by the respective faunal abundance and the estimated daily biomass consumption) is used to asses shifts in the ecosystem-scale proportion of C3 and C4 vegetation. In the Plio-Pleistocene, the general paleoenvironmental conditions varied from wooded grassland to grasslands with the total amount of C4 grass cover on the landscape varying between 35% and 91%. Likewise, the paleohabitat reconstructions indicate the presence of grassland, wooded grassland, woodland habitats throughout the Pliocene and in Middle Pleistocene but the relative proportion of the habitats has changed substantially with time. Although this result agrees with the general trend towards more open grassland since the Late Miocene, a rebound of closed habitats and C3 resources from closed canopy woodlands or forests is evident in the middle Pliocene between 3.42 Ma and 3.24 Ma. These changes in the proportion of habitats could have affected the distribution and availability of preferred food resources and has an implication on the interaction of the animals on the paleolandscape and competition for resources.
18Oenamel values also show a wide range of variation within each stratigraphic member and through time. Temporal variation of δ13Cenamel values within a given taxon, as well as differences among sympatric taxa, document different aspects of the environment and climate, including changes in drinking water source, seasonality, and periods of strong
evaporation. Estimated δ13Cmeteoric water based on the most 18O-depleted hippo tooth enamel, displays values of -1.94 / (VSMOW) and -5.24 / (VSMOW) in the Middle Pleistocene of Asbole and middle Pliocene of Galili, respectively. A major shift in the isotopic composition of water at ~ 3.0 Ma was accompanied by a 6.0 / increase from middle Pliocene to the present. While a +3.8 / shift from early to middle Pliocene was documented. The isotopic composition of meteoric water between 4.6 Ma and 4.38 Ma was most 18O-enriched compared to the rest of the Pliocene estimates. Likewise, an increase in the estimated δ13Cmeteoric water values was documented in the Awash Valley and elsewhere in East Africa, which indicate a regional climate change since the early Pliocene. An increase in the aridity, which is expressed as mean annual water deficit (i.e., the difference between potential evapotranspiration and mean annual precipitation) is also evident since the early Pliocene. These changes during the Pliocene in the region may in part be attributed to a regional decrease in the amount of precipitation and changes in the moisture source superimposed on global climate changes.
42
Lamb, Clare. "Stable carbon isotope variation during natural chloromethane and bromomethane production." Thesis, Queen's University Belfast, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.343035.
Full text
43
Loader, Neil J. "The stable isotope dendroclimatology of Pinus sylvestris from Northern Britain." Thesis, University of Cambridge, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.390043.
Full text
44
Thomas, Katherine S. S. M. Massachusetts Institute of Technology. "Organic geochemistry and stable isotope constraints on Precambrian biogeochemical processes." Thesis, Massachusetts Institute of Technology, 2011. http://hdl.handle.net/1721.1/69474.
Full textAbstract:
Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Earth, Atmospheric, and Planetary Sciences, 2011.Cataloged from PDF version of thesis.
Includes bibliographical references (p. 91-101).
Details of the biogeochemical cycles and the dominant mechanisms present in Precambrian remain heavily debated topics. The events of the Late Proterozoic onset to glaciations and what types of early life existed in the Archean are two of the many provoking topics within the Precambrian. We set out to improve the understanding of these geologic intervals by examining stable isotopic signatures and molecular fossils (biomarkers) in Late Proterozoic and Mesoarchean ages sedimentary rocks in Northwestern Territories, Canada and Pilbara, Western Australia, respectively. This thesis presents sulfur, carbon, oxygen and nitrogen stable isotopic data along with distribution of steranes and hopanes biomarkers. Geochemical data is analyzed in the context of elucidating the key biological and environmental factors involved in the Mesoarchean marine biosphere and the Late Proterozoic onset of glaciations. Stable isotopic analysis of the Gorge Creek Group in Pilbara, Western Australia reveals organisms capable of microbial sulfur disproportionation were likely the dominant biological players in Mesoarchean deep-ocean sulfur cycling. Biomarker and isotopic proxies of the Coppercap Formation reveal diverse biological activity directly prior to the Sturtian Glaciation with communities of green and purple sulfur bacteria as well as methanotrophs and cyanobacteria. Possible environmental implications of these communities co-existing are explained in context of changes in ocean chemistry and the diversification of eukaryotic life.
by Katherine S. Thomas.
S.M.
45
Tayasu, Ichiro. "Nutritional ecology of termite-symbionts system using stable isotope techniques." 京都大学 (Kyoto University), 1997. http://hdl.handle.net/2433/64948.
Full text
46
Shahar, Anat. "Non-traditional stable isotope fractionation mechanisms from dust to planets /." Diss., Restricted to subscribing institutions, 2008. http://proquest.umi.com/pqdweb?did=1666911651&sid=1&Fmt=2&clientId=1564&RQT=309&VName=PQD.
Full text
47
Reich, Kimberly Jeanne. "Sea turtle life history patterns revealed through stable isotope analyses." [Gainesville, Fla.] : University of Florida, 2009. http://purl.fcla.edu/fcla/etd/UFE0024416.
Full text
48
Lamonica, Giulia. "Stable isotope tracers to estimate lung surfactant metabolism in vivo." Doctoral thesis, Università degli studi di Padova, 2013. http://hdl.handle.net/11577/3423360.
Full textAbstract:
Aim of this thesis was to apply the stable isotopes technique to study pulmonary surfactant kinetics.
Lung surfactant is essential to live, because it prevents the alveoli to collapse during normal breathing. Lung surfactant is composed of lipids and specific proteins, and nowadays it is well known that alterations on the composition and amount of surfactant are involved in acute and chronic lung diseases.
This work presents two studies about lung surfactant kinetics.
The first one is about the synthesis of disaturated phosphatidylcholine, the main lipid in the pulmonary surfactant system, in a murine model of unilateral acid injury.
The second one explains an optimized procedure to evaluate surfactant protein B synthesis and a novel method to study surfactant protein C synthesis in both infants and adults, each with stable isotopes techniqueObiettivo di questa tesi è stato quello di applicare l’uso degli isotopi stabili come traccianti metabolici allo studio del metabolismo del surfattante polmonare. Il surfattante polmonare è una sostanza fondamentale per vivere in quanto impedisce agli alveoli di collassare durante l’atto respiratorio. Il surfattante polmonare è composto da lipidi e proteine specifiche, ed è ormai noto che alterazioni nella composizione e nella quantità del surfattante polmonare sono presenti nella malattia respiratoria acuta e cronica. In questo lavoro vengono presentati due studi sulla cinetica del surfattante polmonare: il primo riguarda la sintesi del lipide maggiormente presente nel surfattante, ovvero la fosfatidilcolina disatura, in una condizione di danno unilaterale da acido in un modello murino. Il secondo studio riguarda un metodo ottimizzato per misurare la sintesi della proteina B del surfattante e un nuovo metodo per valutare, sempre con l’utilizzo degli isotopi stabili, la sintesi della proteina C del surfattante in bambini e adulti
49
Kelly, Simon Douglas. "The development of continuous-flow isotope ratio mass spectrometry methods and their application to the detection of food adulteration." Thesis, University of East Anglia, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.251500.
Full text
50
Nordhoff, Peter. "Stable isotope investigations on speleothems from different cave systems in Germany." Doctoral thesis, [S.l.] : [s.n.], 2005. http://webdoc.sub.gwdg.de/diss/2005/nordhoff.
Full text