This thesis deals with the development of farming landscapes in the Thames Valley from the Neolithic to the Roman period (4000 BCE - 410 CE). The focus is on the major domestic animal species, cattle, sheep and pig, and their roles in the agroecosystem, traced using carbon and nitrogen isotope ratios measured in collagen. The large dataset of faunal isotope values from a limited area, obtained from sites with extensive archaeological and environmental information, allowed a thorough characterisation of variability in isotope values, within and between species, sites, archaeological periods, and landscape regions. Isotope ratios in a flock of modern sheep showed less variability than archaeological assemblages. Linear mixed models were used to analyse variation in isotope values in 1490 archaeological samples from 23 sites. The pattern of change over time differed for cattle, sheep and pig, reflecting both wide-scale environmental change and changes in animal management. d13C values of cattle and pigs reflected the loss of primary closed-canopy woodland. Pig management changed from an emphasis on woodland resources to a closer association with settlement and consumption of anthropogenic waste. Herbivore d15N values probably reflect variations in the intensity of pasture use and association with arable farming. Climatic cooling since the post-glacial thermal maximum cannot explain these varied trajectories of change. Variation between sites in faunal isotope values was related to landscape regions. Faunal isotope values at individual sites were useful in site interpretation in the context of other evidence. The trend in pig and cattle δ13C values with time was widely found in the UK, as expected if it represents forest clearance. In the Neolithic, cattle management was similar to the UK at central and eastern European Neolithic sites, but pig management was different. Patterns of faunal isotope values and their changes over time, analysed in the context of archaeological and environmental information, can contribute to the interpretation of sites, and give a unique perspective on changes in farming practice and their effects on the landscape.

Submitted by Biblioteca de Pós-Graduação em Geoquímica BGQ (bgq@ndc.uff.br) on 2017-03-14T18:31:18Z No. of bitstreams: 1 Dissertação_MarinaAlves.pdf: 2711910 bytes, checksum: 2be4e3e9354ac9d7fcc36ea36bfd6cee (MD5) / Made available in DSpace on 2017-03-14T18:31:18Z (GMT). No. of bitstreams: 1 Dissertação_MarinaAlves.pdf: 2711910 bytes, checksum: 2be4e3e9354ac9d7fcc36ea36bfd6cee (MD5) / Universidade Federal Fluminense. Instituto de Química. Programa de Pós-Graduação em Geociências- Geoquímica, Niterói, RJ / O Complexo Estuarino-Lagunar Mundaú-Manguaba (CELMM), situado no litoral nordeste do Brasil, vem sofrendo um processo contínuo de degradação ambiental, relacionado principalmente aos efluentes da agroindústria canavieira e ao crescimento urbano desordenado. Traçadores geoquímicos têm sido uma eficiente ferramenta na determinação da origem da matéria orgânica em sedimentos, se alóctone ou autóctone, podendo ser utilizados para identificar possíveis fontes de poluição produzidas por atividades antrópicas, bem como mudanças naturais no ambiente. Nesse contexto, esse trabalho teve como objetivo identificar a origem, transformação e acumulação recente da matéria orgânica nos sedimentos do CELMM. Para tal, cinco testemunhos, dois representando cada laguna, e um fluvial (Rio Mundaú), foram analisados quanto à distribuição vertical dos teores de argila, silte e areia, de carbono orgânico, da razão C/N, do 13C e de ligninas. A distribuição dos parâmetros analisados mostrou que a matéria orgânica sedimentar das lagunas tem origem predominantemente da sua própria produção primária fitoplanctônica. No entanto, a presença de ligninas, mesmo em baixas concentrações, indica a presença de material vegetal alóctone. No Rio Mundaú verificou-se a presença de material proveniente de angiospermas lenhosas, enquanto nas lagunas há grande mistura de angiospermas lenhosas e não lenhosas, sem um padrão claro de distribuição ao longo dos perfis. As razões (Ad/Al)v demonstraram que as ligninas encontradas possuem certo grau de degradação, contribuindo para uma possível redução na concentração total das mesmas, além de alterações nas razões S/V e C/V. A aplicação do índice LPVI (Lignin-Phenol Vegetation Index) para os lignino-fenóis permitiu obter maior clareza a cerca da evolução das fontes de material terrestre para o sistema, de forma que ficou evidente a transição de angiospermas lenhosas, vegetação anteriormente natural na bacia de drenagem, para angiospermas não lenhosas, a partir da expansão da atividade canavieira na região. Além disso, os resultados de acumulação de matéria orgânica nos sedimentos das lagunas demonstram um aumento de produtividade nas camadas mais recentes, como provável conseqüência dos efeitos da expansão agrícola e urbana no CELMM. / The Mundaú-Manguaba Estuarine-Lagoon System (MMELS), located in northeastern Brazil, has been undergoing a continuous process of environmental degradation, mainly related to the input of effluents from the sugar-cane industry and uncontrolled demographic expansion. Geochemical tracers have been an effective tool in determining allochthonous and autochtonous sources of organic matter in sediments. They have been applied to identify possible sources of pollution produced by human activities and natural changes in the environment. In this context, this study aimed to identify the origin, transformations and recent accumulation of organic matter in the sediments of MMELS. Five short cores, two representing each lagoon and one the fluvial end-member (Mundaú River), were analyzed for the vertical distribution of clay, silt and sand, organic carbon, the C/N ratio, 13C and lignins. The parameters showed that the sedimentary organic matter in the lagoons originated largely from its own phytoplanktonic primary production. However, the presence of lignin, albeit at low concentrations, indicated the presence of allochthonous plant material. In Mundaú River the presence of material derived from woody angiosperms was evident, while the lagoons exhibited a mixture of woody and non-woody materials, without a clear distributional pattern along the vertical profiles. The (Ad/Al)v ratios showed that the lignins were subject to a certain degree of degradation, contributing to a possible reduction in their total concentration and changes in the lignin-phenol S/V and C/V ratios. The application of the LPVI index (Lignin-Phenol Vegetation Index) for lignin-phenols allowed for a better understanding on the evolution of terrestrial material sources to the system, with a clear transition from woody angiosperms, representing the original vegetation in the drainage basin, to non-woody angiosperms, corroborating the expansion of sugar cane cultivation in the region. In addition, the results of organic matter accumulation in the lagoon’s sediments showed an increase of primary productivity in the more recent layers at the top of the cores, likely reflecting the effects of agricultural and urban expansion in MMELS

Despite ecological, anthropological, and archaeological debate surrounding their desirability as habitats for human occupation, tropical rainforests have received relatively little attention in discussions of Homo sapiens' Pleistocene dispersal. Sri Lanka has yielded some of the earliest dated fossil and material culture evidence (c. 38-35,000 cal. years BP) for our species in a modern rainforest context beyond Africa. Nevertheless, assertions in Sri Lanka, and elsewhere, regarding early human rainforest reliance have been largely based on coarse or 'off-site' palaeoenvironmental records, and the overall role of these environments in human subsistence strategies has remained uncertain. This study applies stable carbon and oxygen isotope analysis to Sri Lankan human fossil, and associated faunal, tooth enamel dated to between 36-29,000 and 3,000 cal. years BP, in order to directly test human rainforest resource reliance, reconstruct a stable isotope ecology, and develop 'on-site' palaeoenvironmental records for Late Pleistocene-Holocene Sri Lankan rainforest foragers. Stable carbon and oxygen isotope analysis of modern Sri Lankan primates, and stable carbon, oxygen, and nitrogen isotope analysis of modern plant samples from the Polonnaruwa Nature Sanctuary, are also performed to investigate the ecology of Sri Lankan primates on which Late Pleistocene-Holocene forager subsistence strategies were focused. The results demonstrate that Homo sapiens relied on rainforest resources in Sri Lanka from c. 36-29,000 cal. years BP until the Iron Age c. 3 cal. years BP, even when open environments, and their corresponding resources, were available. This remains the case through periods of evident environmental change at the Last Glacial Maximum and even upon the arrival of agriculture in the island's tropical forests. The primate stable isotope data prove difficult to interpret as ecological niche separation in the absence of observation data. Nonetheless, humans were evidently able to not only use but also rapidly specialise in the exploitation of South Asia's rainforests.

The hallmark of oceanic anoxic event 1a (OAE1a) (early Aptian ~125 Ma) corresponds to worldwide deposition of black shales with total organic carbon (TOC) content > 2% and a d13C positive excursion up to ~5‰. OAE1a has been related to large igneous province volcanism and dissociation of methane hydrates during the Lower Cretaceous. However, the occurrence of atypical, coeval and diachronous organic-rich deposits associated with OAE1a, which are also characterized by positive spikes of the d13C in epicontinental to restricted marine environments of the Tethys Ocean, indicates localized responses decoupled from complex global forcing factors. The present research is a high-resolution, multiproxy approach to assess the paleoenvironmental conditions that led to enhanced carbon sequestration from the late Barremian to the middle Aptian in a restricted, Tethyan marginal basin prior to and during OAE1a. I studied the lower 240 m of the El Pui section, Organyà Basin, Spanish Pyrenees. The basin developed as the result of extensional tectonism linked to the opening of the Atlantic Ocean. At the field scale the section consists of a sequence of alternating beds of cm – m-scale, medium-gray to grayish-black limestones and marlstones with TOC up to ~4%. The results indicate that the lowest 85 m of the section, from latest Barremian –earliest Aptian, characterize a deepening phase of the basin concomitant with sustained riverine flux and intensified primary productivity. These changes induced a shift in the sedimentation pattern and decreased the oxygen levels in the water column through organic matter respiration and limited ventilation of the basin. The upper 155 m comprising the earliest – late-early Aptian document the occurrence of OAE1a and its associated geochemical signatures (TOC up to 3% and a positive shift in d13C of ~5‰). However, a low enrichment of redox-sensitive trace elements indicates that the basin did not achieve anoxic conditions. The results also suggest that a shallower-phase of the basin, coeval with platform progradation, may have increased ventilation of the basin at the same time that heightened sedimentation rates and additional input of organic matter from terrestrial sources increased the burial and preservation rate of TOC in the sediment.

Intrusion-related, carbonate rock–hosted replacement deposits are an important source of global base metal production that includes: Cu-Zn skarn, Zn-Pb-Ag carbonate replacement and Ag-base metal deposits. These deposits are located in multiple geological settings and are commonly associated with low-grade Cu-Mo calc-alkaline porphyry districts. Visible alteration halos to these deposits range from ten to hundreds of metres around high temperature skarn deposits, being small to imperceptible around the distal relatively low temperature members of this clan. Patterns of visible and cryptic alteration are described and constrained in this study particularly around paleo-fluid flow zones at different distances and elevations from the ore centre. This was done in order to identify the large-scale zonation, mechanisms, and effects of fluid infiltration especially into the distal portions of these deposits. The main alteration tracers employed included mineralogy, major and trace element geochemistry, oxygen and carbon isotopes, and the fluorescent signature of calcite veins associated with the fluids conduits. Two areas were selected for this study: the large Cu-Zn Antamina skarn and the Ag-base metal Uchucchacua vein deposits in the Peruvian Central Andes as these deposits represent the end-members of the polymetallic carbonate rock-hosted deposits and hence, provide an excellent opportunity to examine the margins and upper sections of these hydrothermal systems. Geochronological analyses of intrusive dikes were used to establish the magmatic and hydrothermal evolution associated with mineralization, as well as the genetic linkage between proximal and distal portions of the mineralizing system at Antamina. Oxygen, carbon and strontium isotope data of vein minerals is also used to constrain the temperature of the fluids proximal and distal to the magmatic centre. Chemical data of fluorescent and non-fluorescent veins were used to determine the main activators of fluorescence and to constrain its relationship with mineralizing fluids. In summary, results of this research identify a large-scale zonation of visible and cryptic alteration around paleo-fluid flow zones demonstrating the linkage between Ag-base metal veins, replacement and skarn deposits. Anomalous halos determined throughout Antamina and Uchucchacua deposits may contribute to the development of a more systematic exploration methodology for these types of deposits. / Science, Faculty of / Earth, Ocean and Atmospheric Sciences, Department of / Graduate

Les matières organiques dissoutes (MOD), en tant que sources de nutriments ou potentiels vecteurs de pollution, sont impliquées dans de nombreuses problématiques environnementales. Bien qu'elles fassent l'objet de nombreuses études depuis plusieurs décennies, les mécanismes gouvernant leur solubilisation et leur transfert depuis les sols vers les systèmes aquatiques demeurent sujets à discussion. En s'appuyant sur l'étude de la composition moléculaire des MOD par hydrolyse et méthylation assistée par température et couplée à la chromatographie en phase gazeuse et à la spectrométrie de masse (HMT-CPG-SM), cette thèse a pour objectif d'apporter une meilleure compréhension de leurs mécanismes de solubilisation et de transfert à l'échelle d'un bassin versant agricole. Ce travail s'est appuyé sur le bassin versant expérimental de Kervidy-Naizin (Morbihan, Observatoire de Recherche en Environnement AgrHys) afin d'observer les processus mis en jeux à deux échelles temporelles différentes. A l'échelle de la crue, ce travail a permis de préciser l'impact des conditions hydrologiques spécifiques sur la dynamique des MOD. A l'échelle annuelle, l'utilisation conjointe de la signature isotopique du carbone (δ13C) et de la composition moléculaire des MOD a permis de préciser les mécanismes de transfert de MOD impliqués à l'échelle du versant. L'utilisation de la HMT-CPG-SM s'est avéré un outil adéquat pour l'étude de la dynamique des MOD. L'ensemble des résultats ainsi obtenus ont permis de souligner l'importance des conditions hydrologiques et en particulier de la dynamique de nappe dans les processus de solubilisation et de transfert des MOD. / Dissolved organic matter (DOM), as sources of nutrient or pollutant dissemination pathway are implied in numerous environmental issues. Although DOM have been the subject of numerous studies for several decades, the mechanisms implied for their solubilization and their transport from soils to aquatic systems are still a matter of discussion. Based on DOM molecular composition determined using thermally assisted hydrolysis and methylation –gas chromatography – mass spectrometry (THM-GC-MS), this thesis aims to provide a better understanding of their solubilization and transfer mechanisms at the scale of an agricultural headwater catchment. This work was conducted on the experimental headwater catchment of Kervidy-Naizin (France, Environmental Research Observatory AgrHys) in order to determine the processes implied at two temporal scales. At the scale of a rain event, this work has clarified the impact of hydrological conditions on the DOM dynamics. At annual scale, the use of carbon isotope signature (δ13C) and DOM molecular composition allowed to clarify the DOM transfer mechanisms at the slope scale. The use of THM-GC-MS appears to be a suitable tool for the study of DOM dynamics. The results thus obtained allowed to highlight the role of hydrological conditions and in particular the water-table level in the solubilization and transfer of DOM.

No description available.

Depuis les années 1970, de nombreuses études ont rapporté l’oxydation des substrats énergétiques exogènes au repos ou pendant l’exercice. Les glucides ont gagné en popularité, puisque leur oxydation a été associée avec une amélioration de la performance. Pour étudier l’oxydation des glucides exogènes pendant l’exercice, deux techniques sont nécessaires : la calorimétrie indirecte respiratoire couplée au traçage isotopique. Ce mémoire décrit, dans un premier temps, la calorimétrie indirecte respiratoire en présentant et démontrant les équations utilisées dans cette méthode. La technique de traçage par isotope 13C ou 14C est ensuite présentée en insistant sur le développement des équations sur lesquelles elle repose. Dans un deuxième temps, les facteurs pouvant influencer le taux d’oxydation et la contribution à la fourniture d’énergie du glucose exogène pendant l’exercice prolongé sont rapportés dans les analyses de régressions multiples. L’objectif de cette analyse est d’identifier les facteurs expliquant le mieux la variation de ces deux variables. La grande variabilité existante dans les conditions expérimentales de la littérature rend difficiles les comparaisons. Par conséquent, les analyses sont effectuées sur une condition standard représentant les caractéristiques les plus communes de la littérature. La grande majorité des études ayant été effectuées sur une population semblable (hommes, entre 65 et 80 kg, âgés entre 20 et 40 ans), davantage de travaux sont nécessaires sur d’autres types de population active et sur des sujets d’âge et de masse corporelle différents. Les résultats de cette méta-analyse pourront aider à améliorer les recommandations sur l’ingestion de glucides au cours de l’exercice prolongé. / Since the 1970s, numerous studies have reported the oxidation of exogenous energy substrates at rest or during exercise. Carbohydrates have gained popularity, as their oxidation has been associated with improved performance. To study the oxidation of exogenous carbohydrates during exercise, two techniques are required: indirect respiratory calorimetry coupled with isotope tracing. This dissertation first describes the respiratory indirect calorimetry by presenting and demonstrating the equations used in this method. The 13C or 14C isotope tracing technique is then presented with emphasis on the development of the equations on which it is based. Second, factors that may influence the oxidation rate and contribution to energy supply of exogenous glucose during prolonged exercise are reported the multiple regression analysis. The objective of this analysis is to identify the factors that best explain the variation in these two variables. The large variability existing in the experimental conditions in the literature makes comparisons difficult. Therefore, the analyses are performed on a standard condition representing the most common characteristics in the literature. Because most of the studies were performed on a similar population (men, between 65 and 80 kg, aged between 20 and 40 years), more work is needed on other types of working populations and on subjects of different ages and body mass. The results of this meta-analysis may help improve recommendations for carbohydrate intake during prolonged exercise.

Agricultural yields in Northwest Yucatán are constrained by climate, thin soils, and low fertility. Despite this, the ancient Maya city of Chunchucmil Yucatán, Mexico, boasted an immense, dense, and wealthy population during the Middle Classic period (ca A.D. 400-700). Soil physical and chemical properties were explored to determine how the ancient Maya of Chunchucmil fed themselves. Soil profiles were collected from various locations within ancient Chunchucmil's suspected sustaining area. The physical and chemical properties, carbon isotopes, black carbon, and coprostanols of soil profiles sampled were compared to ancient rural settlement and remotely sensed images, such as AIRSAR (airborne synthetic aperture radar). Our objectives were to geographically determine the areas of agricultural importance and determine whether evidence of ancient agricultural intensification could be observed in the surrounding soil resources of Chunchucmil. Indigenous Maya of the area identify three major soil classes, boxlu'um, saklu'um, and kancab. The ancient Maya likely preferred kancab because it provided some security with higher soil moisture, greater soil depth, and improved nutrient availability. The land use capability is severely limited in the swamp/estuary and tzekel. The lack of rural settlement within these zones suggests that they were not used for cultivation in ancient times; however, the wood resources likely provided Chunchucmil with vital raw materials. The carbon isotopic signature of ancient C4 crops was not detected suggesting that either maize was not extensively produced or that the mix of native C3 and C4 plants in the savanna hid the signature. There were no soil chemical or biomarker evidences of ancient agricultural intensification, suggesting that ancient agriculture was mainly based on shifting cultivation at Chunchucmil. Concentrations of black carbon, calcium, phosphorus, potassium (Olsen Method), magnesium, and organic carbon within urban and rural settlements were enhanced by incidental human activities. We determined that the land requirement would have been extensive to sustain the population of Chunchucmil during the Middle Classic based on traditional agricultural methods. The ancient Maya of Chunchucmil likely traded marine and estuary products from the Gulf coast and other high value trade items for agricultural products from the nearby Puuc Hills.

Tropical forests provide important habitat for a tremendous diversity of plant and animal species. However, limitations in measuring and monitoring the structure and function of tropical forests has caused these systems to remain poorly understood. Remote-sensing technology has provided a powerful tool for quantification of structural patterns and associating these with resource use. Satellite and aerial platforms can be used to collect remotely sensed images of tropical forests that can be applied to ecological research and management. Chapter 1 of this article highlights the resources available for tropical forest remote sensing and presents a case-study that demonstrates its application to a neotropical forest located in the Petén region of northern Guatemala. The ancient polity of Tikal has been extensively studied by archaeologists and soil scientists, but little is known about the subsistence and ancient farming techniques that sustained its inhabitants. The objective of chapter 2 was to create predictive models for ancient maize (Zea mays L.) agriculture in the Tikal National Park, Petén, Guatemala, improving our understanding of settlement patterns and the ecological potentials surrounding the site in a cost effective manner. Ancient maize agriculture was described in this study as carbon (C) isotopic signatures left in the soil humin fraction. Probability models predicting C isotopic enrichment and carbonate C were used to outline areas of potential long term maize agriculture. It was found that the Tikal area not only supports a great variety of potential food production systems but the models suggest multiple maize agricultural practices were used.