Tesis sobre el tema "Pleistocene Climate Changes"
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Chalk, Thomas B. "Boron based insights into Plio-Pleistocene carbon cycle changes and global climate evolution". Thesis, University of Southampton, 2014. https://eprints.soton.ac.uk/374239/.
Texto completoWeirauch, Daniel R. "A high-resolution record of climate instability spanning ~1.0 million years across the mid-Pleistocene transition". Access to citation, abstract and download form provided by ProQuest Information and Learning Company; downloadable PDF file, 131 p, 2007. http://proquest.umi.com/pqdweb?did=1472642111&sid=21&Fmt=2&clientId=8331&RQT=309&VName=PQD.
Texto completoEastwood, Rodney Gordon y N/A. "Ant Association and Speciation in Lycaenidae (Lepidoptera): Consequences of Novel Adaptations and Pleistocene Climate Changes". Griffith University. Australian School of Environmental Studies, 2006. http://www4.gu.edu.au:8080/adt-root/public/adt-QGU20071130.134932.
Texto completoEastwood, Rodney Gordon. "Ant Association and Speciation in Lycaenidae (Lepidoptera): Consequences of Novel Adaptations and Pleistocene Climate Changes". Thesis, Griffith University, 2006. http://hdl.handle.net/10072/365668.
Texto completoThesis (PhD Doctorate)
Doctor of Philosophy (PhD)
Australian School of Environmental Studies
Full Text
Muteveri, Tinashe. "Effect of pleistocene climatic changes on the evolutionary history of South African intertidal gastropods". Thesis, Stellenbosch : Stellenbosch University, 2013. http://hdl.handle.net/10019.1/79791.
Texto completoENGLISH ABSTRACT: Historical vicariant processes due to glaciations, resulting from the large-scale environmental changes during the Pleistocene (0.012-2.6 million years ago, Mya), have had significant impacts on the geographic distribution of species, especially also in marine systems. The motivation for this study was to provide novel information that would enhance ongoing efforts to understand the patterns of biodiversity on the South African coast and to infer the abiotic processes that played a role in shaping the evolution of taxa confined to this region. The principal objective of this study was to explore the effect of Pleistocene climate changes on South Africa′s marine biodiversity using five intertidal gastropods (comprising four rocky shore species Turbo sarmaticus, Oxystele sinensis, Oxystele tigrina, Oxystele variegata, and one sandy shore species Bullia rhodostoma) as indicator species. Sequence data obtained from partial segments of the mitochondrial cytochrome oxidase c subunit 1 (COI), and the nuclear ribosomal DNA (encompassing part of 5.8S, second Internal Transcribed Spacer and part of 28S, hereinafter called ITS2; or comprising part of the first Internal Transcribed Spacer, 5.8S, second Internal Transcribed Spacer and part of 28S, hereinafter called ITS), were used as genetic markers to construct phylogeographic patterns and to investigate demographic histories of the taxa. Population structure was investigated using haplotype network analyses, pairwise ΦST statistics, analysis of molecular variance (AMOVA), isolation by distance analyses, Bayesian analysis of population structure (BAPS) and coalescent analysis of gene flow. Demographic history was analysed through Fu′s Fs tests, mismatch distributions, and Bayesian skyline plots. Demographic analyses suggest that all five intertidal gastropods studied experienced demographic expansions dating to the late Pleistocene. The sandy shore direct developer B. rhodostoma began expansion after the LGM (c. 15 kya) whereas for the four rocky shore broadcast spawners (T. sarmaticus, O. sinensis, O. tigrina, and O. variegata) the onset of expansion coincided with or preceded the LGM (c. 25, 60, 50, 40 kya, respectively). Consistent with recent range expansions and gene flow patterns, the population genetic structure in all species was characterised by shallow or a lack of population differentiation. Oxystele variegata was an exception as it showed a deep disjunction, of late Pleistocene origin, between individuals in the west coast Namaqua Bioregion and those in the south coast Agulhas Bioregion. These results provide strong evidence of the vital role that Pleistocene climatic changes and current regimes played in shaping the nature and distribution of biodiversity on the South African coast. In addition, gene flow in all species, except O. tigrina, was remarkably asymmetrical with the regions around Cape Infanta and Port Elizabeth acting as source populations. Considering the generally weak population genetic structure and gene flow patterns detected for most gastropod species studied here, it is recommended that T. sarmaticus, O. sinensis, O. tigrina and B. rhodostoma be managed as panmictic populations, and that the region encompassing Cape Infanta, and Port Elizabeth should be prioritised for conservation as it appears to harbour source populations. Oxystele variegata was the only species showing distinct population structure and in this instance, species specific conservation efforts should recognize this divergence by treating the two genetic assemblages as distinct management units.
AFRIKAANSE OPSOMMING: Historiese vikariante prosesse kan toegeskryf word aan glasiasie, en het tot gevolg gehad dat grootskaalse veranderinge in die omgewing plaasgevind het tydens die Pleistoseen (,012 - 2.6 miljoen jaar gelede, Mjg). Dit het 'n beduidende impak gehad op die geografiese verspreiding van spesies, veral ook in die mariene stelsels. Die motivering vir hierdie studie was om nuwe data te voorsien wat sal bydrae tot die voortgesette pogings om die patrone van biodiversiteit langs die Suid-Afrikaanse kus te verstaan. Dit sou ook help om die abiotiese prosesse af te lei wat 'n rol gespeel het in die evolusie van taksa wat in hierdie streek voorkom. Die hoofdoel van hierdie studie was om die effek van die Pleistoseen klimaatsveranderinge op Suid-Afrika se mariene biodiversiteit te bepaal deur gebruik te maak van vyf intergety slak spesies as indikatore (vier wat in rotsagtige gebiede voorkom: Turbo sarmaticus, Oxystele sinensis, Oxystele tigrina, Oxystele variegata en 'n sanderige strand spesies: Bullia rhodostoma). Volgorde data verkry vanaf gedeeltelike segmente van die mitochondriale sitochroom oksidase c subeenheid 1 (COI), en die kern ribosomale DNA (bestaande uit 'n deel van 5.8S, tweede interne getranskribeerde spasieërders en 'n deel van 28S), hierna genoem ITS2 is gebruik as genetiese merkers om filogeografiese patrone te dokumenteer en ook om die demografiese geskiedenis van die spesies te ondersoek. Bevolking struktuur is ondersoek deur gebruik te maak van haplotipe netwerk analise, paarsgewyse ΦST statistiek, analise van molekulêre variansie (AMOVA), isolasie deur afstand analise, Bayesiaanse analise van die bevolking struktuur (BAPS) en analise van gene vloei. Demografiese geskiedenis is ontleed deur Fu se Fs toetse, misparing verdelings, en Bayesiaanse luglyn kurwes. Demografiese ontleding dui daarop dat al vyf die intergety slakke wat ondersoek is demografiese uitbreidings ervaar het wat terugdateer tot die einde van die Pleistoseen. Die sanderige strand direkte ontwikkelaar, B. rhodostoma, het die uitbreiding begin na die LGM (c. 15 Kya), terwyl vir die vier rotsagtige kusbewoners wat eiers oor 'n uitgebreide gebiede versprei (T. sarmaticus, O. sinensis, O. tigrina, en O. variegata) het die aanvang van die bevolkings uitbreiding saamgeval met die laaste galsiasie of dit voorafgegaan (c. 25, 60, 50, 40 Kya, onderskeidelik). In ooreenstemming met die onlangse reeks bevolkings uitbreidings, is die bevolking genetiese struktuur in alle spesies gekenmerk deur weinig differensiasie. Oxystele variegata was 'n uitsondering en het 'n ontwrigting van laat Pleistoceen oorsprong getoon tussen individue langs die weskus Namaqua Biostreek en dié in die suid kus Agulhas biostreek. Hierdie resultate voorsien sterk bewyse van die belangrike rol wat die Pleistoseen klimaatsveranderinge gespeel het in die vorming en verspreiding van biodiversiteit langs die Suid-Afrikaanse kus. Daarbenewens, geen vloei in alle spesies, behalwe O. tigrina, was merkwaardig asimmetries. Kaap Infanta en Port Elizabeth verteenwoordig moontlik die bron bevolkings. Met inagneming van die geringe bevolking genetiese struktuur en geenvloei patrone wat waargeneem is vir die meeste slak spesies wat bestudeer is, word dit aanbeveel dat T. sarmaticus, O. sinensis, O. tigrina en B. rhodostoma bestuur word as 'n panmiktiese bevolking, en dat die streek wat Kaap Infanta en Port Elizabeth insluit geprioritiseer moet word vir bewaring. Oxystele variegata was die enigste spesie wat duidelike bevolking struktuur getoon het en in hierdie geval, moet spesie spesifieke bewaringspogings aangewend word.
Heard, Joshua Andrews. "Late Pleistocene and Holocene Aged Glacial and Climatic Reconstructions in the Goat Rocks Wilderness, Washington, United States". PDXScholar, 2012. https://pdxscholar.library.pdx.edu/open_access_etds/557.
Texto completoRech, André Rodrigo 1985. "Walking through the flower fields = the role of time and space on the evolution of pollination strategies". [s.n.], 2014. http://repositorio.unicamp.br/jspui/handle/REPOSIP/315723.
Texto completoTexto em português e inglês
Tese (doutorado) - Universidade Estadual de Campinas, Instituto de Biologia
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Resumo: Os padrões encontrados em ecologia são resultado de processos contemporâneos interagindo com uma longa história de contingência. No entanto, poucos estudos têm buscado entender o papel relativo de fatores contemporâneos e pretéritos sobre padrões reprodutivos de plantas. No decorrer dessa tese foram consideradas essas duas dimensões (temporal e espacial) em estudos sobre polinização. A amplitude do estudo em relação ao tempo foi de horas até milênios, da mesma forma que para o espaço, para o qual se considerou desde metros até variações entre diferentes continentes na escala planetária. Os capítulos estão organizados em uma escala crescente de tempo e espaço. No primeiro capítulo foi considerada a variação fina de horas e metros no estudo sobre a polinização de algumas espécies de Davilla; nesse capítulo também são apresentados outros aspectos da história natural na família Dilleniaceae e uma abordagem filogenética para a evolução de algumas características florais. No capítulo 2, ao longo de vários anos, foi verificada a habilidade de visitantes florais depositar pólen, sua frequência e a importância de cada grupo de visitante nas flores de Knautia arvensis nesse período. O capítulo 3 demonstra variações no espaço tanto na morfologia floral e foliar como no crescimento do tubo polínico em diferentes testes de polinização, utilizando Curatella americana com populações distribuídas no Cerrado Brasileiro. No capítulo 4 é apresentada a variação espacial no sistema reprodutivo e a relação dos polinizadores com o nível de polinização cruzada e do passado climático com o nível de autopolinização espontânea, também tratando de C. americana. Para finalizar o capítulo 5 considera 50 inventários distribuidos ao redor do planeta categorizando as plantas em anemófilas ou zoófilas e demonstra o papel da precipitação (presente e passada) e da riqueza de espécies vegetais na prevalência de cada um dos modos de polinização. Como conclusão geral, fica clara a importância de se considerar as dimensões temporal e espacial nas interações entre plantas e polinizadores, a fim de entender como essas evoluem e como impactam na evolução da morfologia floral e nos sistemas de polinização
Abstract: Patterns in ecology are the products of current factors interacting with a longstanding history of contingency. Nevertheless, few studies have attempted to disentangle the contribution of past and current factors on plant reproduction patterns. Here we studied pollination considering both, spatial and temporal dimensions. Time variation goes from hours to millennia as well as space, whose importance was considered from meters to the whole planet. The chapter¿s sequence within the thesis is planned to go from the small to the large scale. We show the importance of fine grained variations such as hours and meters in the flower differentiation and pollination of two Davilla species in the chapter 1. In the chapter 2 we studied pollen deposition and visitation frequency in Knautia arvensis considering a year scale and showed the most important pollinator changing every year. In the Chapters 3 we used Curatella americana with populations studied across Brazilian Cerrado and show spatial variation in flower and leaf morphology and pollen tube growth. Chapter 4 also using C. americana shows the variation on the reproductive system across space, with cross-pollination related to pollinator availability and the level of autogamy underpinned by past climate. To finish, Chapter 5 deal with 50 community-based assessments of wind and animal pollination over the world and show the importance of precipitation (current and past) and plant species richness as major drivers of these proportion. As a general conclusion, it is clear that temporal and spatial factors cannot be ignored in spite to understand floral evolution and the interactions between plant and pollinators
Doutorado
Ecologia
Doutor em Ecologia
Lisiecki, Lorraine E. "Paleoclimate time series : new alignment and compositing techniques, a 5.3-MYR benthic [exponents] d18O stack, and analysis of Pliocene-Pleistocene climate transitions /". View online version; access limited to Brown University users, 2005. http://wwwlib.umi.com/dissertations/fullcit/3174639.
Texto completoFurini, Paulo Roberto. "Modelagem preditiva de distribuição passada e futura de Ficus adhatodifolia Schott., Ficus insipida Willd. e Ficus citrifolia Mil. (Moraceae)". Universidade de São Paulo, 2015. http://www.teses.usp.br/teses/disponiveis/59/59139/tde-26052015-143536/.
Texto completoThe Quaternary glaciations shaped the phylogeographic patterns of species in general. In some regions of South America (e.g.Cerrado and Caatinga) structural change was more pronounced and savannas predominated, whereas in other regions (e.g. Amazon and Atlantic Forest) changes were minor, forming areas of forest refuges. Species distribution Predictive Modeling uses associations between environmental variables and species occurrence records to estimate models that represent the environmental conditions favorable to the species. In the present study we chose three species of Neotropical Ficus with different ecological characteristics, representing two independent phylogenetic lineages, i.e., sections Americana (Ficus citrifolia) and Pharmacosycea (F.adhatodifolia and F.insipida). We generated models for the past (interglacial 140,000 years ago and Glacial 21,000 years ago), present and future scenarios (2050 and 2070 in optimistic and pessimistic scenarios) for the three study species using Maxent 3.3.3k program. Our results showed thatfor F. adhatodifolia the most important variables in the models were minimum temperature in the coldest month and precipitation in the driest month. For F.insipida the most important variables in the models were minimum temperature in the coldest month and annual precipitation. For F. citrifolia the most important variables in the models were minimum temperature in the coldest month and precipitation in the wettest month. The models designed for the interglacial stage showed areas of environmental suitability similar to the current scenario of the three species. During the glacial period F. adhatodifolia showed a considerable change in its range, occurring in regions considered refuges for some species. Ficus insipida had its environmental suitability decreased, but remained in the Amazon region, while F. citrifolia increased its area of suitability. In the future models (2050 and 2070) F.adhatodifolia showed a decrease in its range on both optimistic and pessimistic scenarios, F.insipida showed an increase in its area of environmental suitability and F.citrifolia has been decreasing and fragmentation in the Amazon region in the optimistic and pessimistic scenarios 2050 and optimistic 2070. The environmental requirements and the potential phylogeographic patterns of the study species are discussed in the context of the generated predictive models.
Tan, Ning. "Comprendre l’évolution de la cryosphère et du climat du Pliocène à la transition Plio-Pléistocène". Thesis, Université Paris-Saclay (ComUE), 2018. http://www.theses.fr/2018SACLV032/document.
Texto completoThis thesis is devoted tounderstanding the interaction betweencryosphere and climate from the mid Plioceneto the early Quaternary during the onset ofNorthern Hemisphere Glaciation (NHG).Firstly, we investigate the causes for thedevelopment and decay of the large but shortliving glaciation that occurred during MarineIsotope Stage 2 (M2, 3.264-¬3.312 Ma);Secondly, in the framework of the internationalPliocene Model Intercomparison Project(PLIOMIP2), we study the climate of Mid-Piacenzian Warm Period (MPWP, 3.3-3.0Ma).Thirdly, we explore the Plio-PleistoceneTransition (PPT, 3.0-2.5Ma) with anappropriate asynchronously coupled climatecryosphere model. Through these differentperiods, we provide a better understanding ofthe relationship between pCO2, tectonics andclimat during the transition from a warm andhigh-CO2 world to the cold and low-CO2Quaternary glaciations. This work also pointsout the necessity to further study the linkbetween ocean dynamics, carbon cycle andclimate
Missura, Ronaldo [UNESP]. "Análise morfoestratigráfica da Bacia do Ribeirão dos Poncianos - MG". Universidade Estadual Paulista (UNESP), 2005. http://hdl.handle.net/11449/95600.
Texto completoCoordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
A Bacia do Ribeirão dos Poncianos, situada na região ocidental da Serra da Mantiqueira, porção Mineira. Na área são evidenciados controles estruturais que influenciam a drenagem e a disposição do relevo, bem como os depósitos fluviais encontrados na área. Estes fenômenos puderam ser comprovados pela análise dos dados morfométricos gerados nesta pesquisa. Além dos controles estruturais, também foram estudados materiais sedimentares que estruturam os colúvios existentes em algumas vertentes da área de estudo. Estes colúvios localizam-se a setores da vertente de anfiteatro suspenso desarticulado do nível de base atual e anfiteatro articulado ao nível de base. A análise das amostras destes materiais coluviais e das datas obtidas para estes indicam que são fruto de mudanças climáticas que ocorreram durante o Pleistoceno Superior. Suas origens estão vinculadas a movimentos gravitacionais lentos (colúvios) e soterramento de material vegetal (Turfeiras), os limites entre estes se fazem na forma de discordância erosiva e deposicional. Os materiais encontrados apresentam características diferenciadas o que proporcionou através de sua análise atribuir-lhes como sendo fruto de flutuação climáticas ocorridas no período Quaternário.
The Basin of Ribeirão dos Poncianos, located on ocidental Serra da Mantiqueira, Minas Gerais side. The area show evidences of structural controls on drainage, relief and, fluvial deposits. This process could be proved by the analysis of morphometrical data produced in this research. Moreover the structural controls, also studied the sedimentary materials that structured the coluvium that appear in some slopes on the area. This colluvials material is located in sectors of slope of hollows unlinked to current base level and hollow linked to base level. The analyses of colluvial samples and the ages of this materials indicate that is consequence of climatic changes that occur during Upper Pleistocene. The materials origin its linked to gravitational slow movements (colluvium) and buried organic materials (peat), the limits between this materials is made by erosive and depositional discordance. The materials founded show differentiated characteristics that provided by the analysis to attribute than like a results of climatic changes occurred at Quaternary period.
Hocknull, Scott Alexander Biological Earth & Environmental Sciences Faculty of Science UNSW. "Late Cainozoic rainforest vertebrates from Australopapua: evolution, biogeography and extinction". Awarded by:University of New South Wales. Biological, Earth & Environmental Sciences, 2009. http://handle.unsw.edu.au/1959.4/44580.
Texto completoMcGarry, Siobhan Frances. "Multi-proxy Quaternary palaeoenvironmental records from speleothem pollen and organic acid fluorescence". Thesis, University of Exeter, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.341161.
Texto completoPrice, Gilbert J. "Pleistocene palaeoecology of the eastern Darling Downs". Thesis, Queensland University of Technology, 2006. https://eprints.qut.edu.au/16271/1/Gilbert_Price_Thesis.pdf.
Texto completoPrice, Gilbert J. "Pleistocene palaeoecology of the eastern Darling Downs". Queensland University of Technology, 2006. http://eprints.qut.edu.au/16271/.
Texto completoGrant, Katharine M. "Sea-level change, monsoon variability, and eastern Mediterranean climate over the Late Pleistocene". Thesis, University of Southampton, 2013. https://eprints.soton.ac.uk/362005/.
Texto completoJones, Andrew G. "Testing the Freshwater Routing Hypothesis for Abrupt Climate Change with a Hudson River Paleodischarge Record". Thesis, Boston College, 2015. http://hdl.handle.net/2345/bc-ir:104217.
Texto completoThe mechanisms of abrupt climate change during the last glacial period are not yet fully understood. The objective of this research is to use oxygen isotope and magnesium/calcium ratios from foraminifera in a marine sediment core <200 km southeast of New York City (Ocean Drilling Program 174 Site 1073A) to test the hypothesis that changes in freshwater run-off patterns during intermediate extensions of the Laurentide Ice Sheet caused abrupt climate change by disrupting the Atlantic thermohaline circulation. The combination of foraminiferal δ18O and Mg/Ca yields salinity as an isolated variable, which is used as a proxy for Hudson River discharge through ~42,000-28,000 years ago. This thesis reviews the literature on abrupt climate change and compares the Hudson River paleodischarge record to established records of abrupt climate events observed in Greenland ice cores. It concludes that a higher resolution of data points is required to evaluate the impact of Hudson River discharge on abrupt climate change
Thesis (BS) — Boston College, 2015
Submitted to: Boston College. College of Arts and Sciences
Discipline: Departmental Honors
Discipline: Earth and Environmental Sciences
Baxstrom, Kelli W. "Climate and Vegetation Change in Late Pleistocene Central Appalachia: Evidence fromStalagmites and Lake Cores". Ohio University / OhioLINK, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1554978401327246.
Texto completoLang, David. "Continental climate and ocean circulation change during the Pliocene-Pleistocene intensification of Northern Hemisphere Glaciation". Thesis, University of Southampton, 2015. https://eprints.soton.ac.uk/385217/.
Texto completoPeryam, Thomas y Thomas Peryam. "Sedimentation, Climate Change and Tectonics: Dynamic Stratigraphy of the Pliocene-Pleistocene Fish Creek-Vallecito Basin, California". Thesis, University of Oregon, 2012. http://hdl.handle.net/1794/12519.
Texto completoBischoff, Juliane. "Microbial communities and their response to Pleistocene and Holocene climate variabilities in the Russian Arctic". Phd thesis, Universität Potsdam, 2013. http://opus.kobv.de/ubp/volltexte/2013/6889/.
Texto completoDie Arktis ist in den gegenwärtigen Diskussionen zum Klimawandel von besonderem Interesse. Die derzeitig beobachtete globale Erwärmung ist in den hohen nördlichen Breiten besonders ausgeprägt. Dies führt dazu, dass ehemals gefrorene Böden zunehmend tiefer auftauen und daher im Boden enthaltene Kohlenstoffquellen für die mikrobielle Umsetzung und Mineralisierung zur Verfügung stehen. Aufgrund dieser Prozesse entstehen klimarelevant Gase, darunter Kohlendioxid und Methan, die aus den Böden und Sedimenten freigesetzt werden können. Wenn man bedenkt, dass in den nördlichen Permafrostgebieten die Hälfte des weltweit unter der Bodenoberfläche gelagerten Kohlenstoffs gelagert ist, wird die Bedeutung dieser Region für das Verständnis des globalen Kohlenstoffkreislaufes und der möglichen Treibhaus-gasemissionen sichtbar. Trotz dieser Relevanz, sind die am Kohlenstoffumsatz beteiligten Mikroorganismen in der Arktis wenig untersucht und ihre Anpassungsfähigkeit an die gegenwärtigen Klimaveränderungen unbekannt. Die vorliegende Arbeit untersucht daher, wie sich Klimaveränderungen in der Vergangenheit auf die Anzahl und Zusammensetzung der mikrobiellen Gemeinschaften ausgewirkt haben. Dabei liegt ein besonderer Fokus auf die methanbildenden Archaeen, um das Verständnis der mikrobiellen Methandynamik zu vertiefen. Im Rahmen dieser Arbeit wurden drei Bohrkerne aus zwei verschiedenen Standorten in der russischen Arktis untersucht, darunter terrestrischer Permafrost und Seesedimente aus Sibirien und Chukotka, Russland. Mittels der Identifikation und Quantifizierung von mikrobiellen Genen und charakteristischen Bestandteilen der mikrobiellen Zellmembran war es möglich, fossile mikrobielle Gemeinschaften in Seesedimenten mit einem Alter von bis zu 480 000 Jahren und in Permafrostablagerungen mit einem Alter von bis zu 42 000 Jahren zu rekonstruieren. Es wurde gezeigt, dass es während vergangener warmen Perioden zu einem Wachstum von Bakterien und Archaeen in allen untersuchten Standorten gekommen ist. Dieser Trend konnte auch für die Gemeinschaft der methanogenen Archaeen gezeigt werden, die während warmen und insbesondere feuchten Klimabedingungen in großer Anzahl und Diversität vorhanden waren, was wiederrum Rückschlüsse auf mögliche Methanemissionen erlaubt. In den terrestrischen Permafroststandorten wird der Temperaturanstieg als direkte Ursache für die gefundene Reaktion der mikrobiellen Gemeinschaft vermutet. Im Gegenzug dazu, führte der Temperaturanstieg im untersuchten arktischen See wahrscheinlich zu einer erhöhten Primärproduktion von organischem Kohlenstoff, die wiederum das Wachstum der Mikroorganismen antrieb. Weiterhin konnte im Rahmen dieser Arbeit gezeigt werden, dass Methanosarcina-verwandte Spezies in der Russischen Arktis weit verbreitet sind und sich an veränderte Umweltbedingungen gut anpassen können. Im Gegensatz dazu stehen Vertreter von Methanocellales und Methano-microbiales, die nicht in der Lage sich an veränderte Lebensbedingungen anzupassen. Im Rahmen dieser Arbeit konnte erstmalig gezeigt werden, dass es in früheren Warmphasen zu einem vermehrten Wachstum der an der Umsetzung des organischen Kohlenstoffs beteiligten Mikroorganismen in der Russischen Arktis gekommen ist. Im Zusammenhang mit der zukünftigen Erwärmung der Arktis kann also von einer Veränderung der am Kohlenstoffkreislauf beteiligten Mikroorganismen ausgegangen werden kann. Mit den steigenden Temperaturen werden sich einige Vertreter der methanproduzierenden Mikroorganismen an die veränderten Bedingungen anpassen können, während Temperatur-empfindliche Vertreter aus dem Habitat verdrängt werden. Diese Veränderungen in der mikrobiellen Gemeinschaft können die Methanproduktion der hohen noerdlichen Breiten erhoehen und dazu beitragen, dass aus der Arktis als eine Kohlenstoffsenke eine Kohlenstoffquelle wird.
Bradley, Dawn Marie. "Implications of Late Pleistocene Climatic Change on the Morphological Variations of the Neanderthal". Digital Archive @ GSU, 2006. http://digitalarchive.gsu.edu/geosciences_theses/4.
Texto completoWall-Palmer, Deborah. "Response of pteropod and related faunas to climate change and ocean acidification". Thesis, University of Plymouth, 2013. http://hdl.handle.net/10026.1/1398.
Texto completoPilaar, Birch Suzanne Elizabeth. "Human adaptations to climate change and sea level rise at the pleistocene-holocene transition in the Northeastern Adriatic". Thesis, University of Cambridge, 2013. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.607721.
Texto completoMissura, Ronaldo. "Análise morfoestratigráfica da Bacia do Ribeirão dos Poncianos - MG /". Rio Claro : [s.n.], 2005. http://hdl.handle.net/11449/95600.
Texto completoBanca: Regina Célia de Oliveira
Banca: Cenira Maria Lupinacci da Cunha
Resumo: A Bacia do Ribeirão dos Poncianos, situada na região ocidental da Serra da Mantiqueira, porção Mineira. Na área são evidenciados controles estruturais que influenciam a drenagem e a disposição do relevo, bem como os depósitos fluviais encontrados na área. Estes fenômenos puderam ser comprovados pela análise dos dados morfométricos gerados nesta pesquisa. Além dos controles estruturais, também foram estudados materiais sedimentares que estruturam os colúvios existentes em algumas vertentes da área de estudo. Estes colúvios localizam-se a setores da vertente de anfiteatro suspenso desarticulado do nível de base atual e anfiteatro articulado ao nível de base. A análise das amostras destes materiais coluviais e das datas obtidas para estes indicam que são fruto de mudanças climáticas que ocorreram durante o Pleistoceno Superior. Suas origens estão vinculadas a movimentos gravitacionais lentos (colúvios) e soterramento de material vegetal (Turfeiras), os limites entre estes se fazem na forma de discordância erosiva e deposicional. Os materiais encontrados apresentam características diferenciadas o que proporcionou através de sua análise atribuir-lhes como sendo fruto de flutuação climáticas ocorridas no período Quaternário.
Abstract: The Basin of Ribeirão dos Poncianos, located on ocidental Serra da Mantiqueira, Minas Gerais side. The area show evidences of structural controls on drainage, relief and, fluvial deposits. This process could be proved by the analysis of morphometrical data produced in this research. Moreover the structural controls, also studied the sedimentary materials that structured the coluvium that appear in some slopes on the area. This colluvials material is located in sectors of slope of hollows unlinked to current base level and hollow linked to base level. The analyses of colluvial samples and the ages of this materials indicate that is consequence of climatic changes that occur during Upper Pleistocene. The materials origin its linked to gravitational slow movements (colluvium) and buried organic materials (peat), the limits between this materials is made by erosive and depositional discordance. The materials founded show differentiated characteristics that provided by the analysis to attribute than like a results of climatic changes occurred at Quaternary period.
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Prieto, Alfredo y Rafael Labarca. "The Late Pleistocene Southern Fuego-Patagonian Archaeological Sites: New Findings, New Problems". Pontificia Universidad Católica del Perú, 2014. http://repositorio.pucp.edu.pe/index/handle/123456789/113607.
Texto completoLos sitios arqueológicos finipleistocénicos de Fuego-Patagonia austral son bastante escasos. Se cuenta con apenas cinco de ellos para comprender un período que se extiende por cerca de 1000 años. Estos yacimientos coinciden con una etapa de cambios ambientales muy marcados y asisten a la extinción de la megafauna en la región, al igual que en el resto del continente americano. Todos ellos se ubican en cuevas y aleros rocosos. Los intentos por hallar nuevos emplazamientos en otros contextos del área no han dado los frutos esperados aún. Sin embargo, se analizan otras posibilidades de búsqueda a la luz de los resultados de los trabajos recientes de los paleobiólogos comprometidos en obtener registros cada vez más acuciosos del cambio climático y sus causas.
Vázquez, Rivera Héctor. "Changing Climate and Geographical Patterns of Taxonomic Richness". Thesis, Université d'Ottawa / University of Ottawa, 2014. http://hdl.handle.net/10393/31721.
Texto completoWakefield, Amy E. "The Diatom Record of Environmental Change Across the Pliocene-Pleistocene Transition at Lake El'gygytgyn, Northeast Russia". Bowling Green State University / OhioLINK, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=bgsu1494764871353507.
Texto completoMartinez, Sandrine. "Palaeoecology of the Mount Etna bat fauna, coastal Eastern Queensland". Thesis, Queensland University of Technology, 2010. https://eprints.qut.edu.au/40979/1/Sandrine_Martinez_Thesis.pdf.
Texto completoMathias, Frank Furlong Jr. "A Plio-Pleistocene Record of Lacustrine Ostracodes from Butte Valley, California: Faunal Responses to Tectonic and Climatic Change". Kent State University / OhioLINK, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=kent1404725598.
Texto completoShackford, Julia Keegan. "Continuous Late Pleistocene Paleoclimate Record from the Southwest African Margin: A Multi-Proxy Approach". unrestricted, 2005. http://etd.gsu.edu/theses/available/etd-04212005-174202/.
Texto completoTitle from title screen. Beth A. Christensen, committee chair; W. Crawford Elliott, Eirik J. Krogstad, Deborah Freile, committee members. Description based on contents viewed Dec. 22, 2006. Includes bibliographical references (p. 107-112).
Doughty, Alice Marie. "10Be Cosmogenic Exposure Ages of Late Pleistocene Moraines Near the Maryburn Gap of the Pukani Basin, New Zealand". Fogler Library, University of Maine, 2008. http://www.library.umaine.edu/theses/pdf/DoughtyAM2008.pdf.
Texto completoCarolin, Stacy Anne. "Geochemistry of karst deposits in Borneo detailing hydroclimate variations in the Warm Pool across the late Pleistocene". Diss., Georgia Institute of Technology, 2014. http://hdl.handle.net/1853/52277.
Texto completoAlizadeh, Kamaleddin [Verfasser], Hermann [Akademischer Betreuer] Behling, Markus [Gutachter] Hauck y Erwin [Gutachter] Bergmeier. "Investigating Environmental (Climate and Vegetation) Change of Eastern Amazonia During Pleistocene and Holocene Using Multi-Proxy Analysis / Kamaleddin Alizadeh ; Gutachter: Markus Hauck, Erwin Bergmeier ; Betreuer: Hermann Behling". Göttingen : Niedersächsische Staats- und Universitätsbibliothek Göttingen, 2018. http://d-nb.info/1150509481/34.
Texto completoPrice, Catherine R. "Late Pleistocene and Early Holocene small mammals in South West Britain : environmental and taphonomic implications, and their role in archaeological research". Thesis, University of South Wales, 2001. https://pure.southwales.ac.uk/en/studentthesis/late-pleistocene-and-early-holocene-small-mammals-in-south-west-britain-environmental-and-taphonomic-implications-and-their-role-in-archaeological-research(0fdb87f2-abcf-4676-9bd3-0a23c9922caf).html.
Texto completoWei-Kang, Ho y 何瑋剛. "Late Pleistocene Climate Changes of Northern Vietnam: Geochemical Characters of a Speleothem". Thesis, 2001. http://ndltd.ncl.edu.tw/handle/60549248559606027878.
Texto completo國立臺灣大學
地質科學研究所
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Speleothems are chemical deposits of CaCO3, usually calcite, precipitated from seepage waters derived from the overlying ground surface. Due to sufficient uranium content in speleothem, they are suitable for U-Th dating and can provide high resolution and continued paleo-environmental information up to 450ka. It can also be correlated with the other high resolution materials, such as ice cores and sediment cores drilled from deep sea. We collected a stalagmite in a cave located 40 km to the south of Hanoi, Vietnam. d13C and d18O values and trace element concentrations are conducted for this stalagmite. The age of the beginning and termination of this stalagmite are determined as 18 and 10ka respectively by U-Th dating method. Based on our results, the paleo-environmental change in north Vietnam is clearly understood. Between 11ka and 10ka, d18O values change rapidly, suggesting heavy rainfall at that time. d13C values become more negative in 17ka and 15ka, indicating that the relative abundance of two groups of plants (C3, C4) changed after LGM. The result of trace element can further explain the events identified above. The fluctuation of Mg/Sr ratios in this research have a good correlation with the change of oxygen isotope of GISP2. We can find Younger Dryas event in north Vietnam by this result. And there are two cold events in this time interval.
Hermanowski, Barbara. "Pleistocene and Holocene environmental changes in the Brazilian Amazon region". Doctoral thesis, 2013. http://hdl.handle.net/11858/00-1735-0000-0022-5E2F-9.
Texto completoLund, David Charles. "Millennial-scale surface and deep water oscillations in the N.E. Pacific : implications for late pleistocene climate change". Thesis, 1997. http://hdl.handle.net/1957/28117.
Texto completoCarto, Shannon Leigh. "Climate model study of the role of global climate in the late Pleistocene migration of anatomically modern humans out of Africa". Thesis, 2006. http://hdl.handle.net/1828/2114.
Texto completoRabanus-Wallace, Mark Timothy. "Climate-driven ecological changes through the last glacial period: innovations in plant ancient DNA and stable isotope palaeoecology". Thesis, 2017. http://hdl.handle.net/2440/114508.
Texto completoThesis (Ph.D.) (Research by Publication) -- University of Adelaide, School of Biological Sciences, 2017.
Marcott, Shaun Andrew. "Late Pleistocene and Holocene glacier and climate change". Thesis, 2011. http://hdl.handle.net/1957/21129.
Texto completoGraduation date: 2011
Access restricted to the OSU Community, at author's request, from May 5, 2011 - May 5, 2012
Griffiths, Michael Lindgren. "Late-Pleistocene climate evolution of the southern sub-equatorial tropics from east-Indonesian speleothems". Thesis, 2010. http://hdl.handle.net/1959.13/807577.
Texto completoThe climate evolution of the southern sub-equatorial tropics during marine isotope stage (MIS)5a/b and the Holocene is explored using geochemical tracers from speleothems on Flores island, Indonesia. Oxygen isotope measurements from two precisely-dated stalagmites reveal that the Australian-Indonesian monsoon increased during the Younger Dryas (YD) cooling event, when Atlantic meridional overturning circulation was relatively weak. Monsoon precipitation intensified even more rapidly from 11 to 7 ka ago, when the Indonesian continental shelf was flooded by global sea-level rise. Analysis of oxygen (δ18O) and hydrogen (δD) isotope ratios from speleothem fluid inclusions shows that inclusion-δ18O values vary in phase with speleothem calcite δ18O during the Holocene, confirming that calcite δ18O primarily reflects variations in the δ18O of meteoric rainfall. Cave drip-water temperatures, reconstructed from coupled measurements of δ18O in speleothem calcite and fluid inclusions, remained relatively constant through the Holocene but were significantly cooler during the YD, consistent with the high northern latitudes. To help confirm the stable isotope records, trace elements were used to reconstruct the position of the austral summer inter-tropical convergence zone and east Indonesian rainfall variability during the Holocene. Mg/Ca and Sr/Ca ratios correlate significantly with one another, and with δ18O and δ13C, throughout the record suggesting that the trace element ratios were dominated by prior calcite precipitation, a process whereby degassing in the vadose zone during periods of low recharge causes deposition of calcite and disproportionate loss of Ca2+ ions (relative to Mg2+ and Sr2+) ‘upstream’ of the stalagmite. Comparison of speleothem δ18O time-series from Flores and Borneo shows that they vary in unison for much of the Holocene. However, there is an exception during the mid-Holocene when a distinct anomaly in δ18O in the Borneo record, possibly caused by a change in the circulation of the Australian-Indonesian summer monsoon (AISM) in response to a period of positive IOD-like conditions in the eastern Indian Ocean, occurred between the two regions. A stalagmite reconstruction of Indo-Pacific climate through the interval 84 - 91 ka shows that the lower-frequency oxygen isotope trend indicates that the AISM was largely controlled by local summer insolation during this time, while the carbon isotopes show a pattern that is closer linked with northern polar-latitude ice-core records. Most notably, an abrupt decrease in the temperature-controlled δ13C values at the MIS 5a/b transition occurs in parallel with GIS 21 in the GISP2 δ18O and CH4 records highlighting the strong connection between the IPWP and North Atlantic during the last glacial period.
Alizadeh, Kamaleddin. "Investigating Environmental (Climate and Vegetation) Change of Eastern Amazonia During Pleistocene and Holocene Using Multi-Proxy Analysis". Doctoral thesis, 2017. http://hdl.handle.net/11858/00-1735-0000-002E-E318-8.
Texto completoPeerdeman, Frank M. "The Pleistocene climatic and sea-level signature of the Northeastern Australian continental margin". Phd thesis, 1993. http://hdl.handle.net/1885/139973.
Texto completoDoughty, Alice Marie. "¹⁰Be cosmogenic exposure ages of late pleistocene moraines near the Maryburn Gap of the Pukani Basin, New Zealand /". 2008. http://www.library.umaine.edu/theses/theses.asp?highlight=1&Cmd=abstract&ID=GEO2008-003.
Texto completoTeske, Peter R., Isabelle Papadopoulos, Christopher D. McQuaid, Brent K. Newman y Nigel P. Barker. "Climate change, genetics or human choice: why were the shells of mankind’s earliest ornament larger in the Pleistocene than in the Holocene?" 2007. http://hdl.handle.net/10962/d1006001.
Texto completoMurad, Waheed. "Late Quaternary Vegetation History And Climate Change In The Gobi Desert, South Mongolia". Doctoral thesis, 2011. http://hdl.handle.net/11858/00-1735-0000-000D-EF60-5.
Texto completoLister, Guy. "Late Pleistocene Alpine deglaciation and post-glacial climatic developments in Switzerland the record from sediments in a peri-alpine lake basin /". 1985. http://catalog.hathitrust.org/api/volumes/oclc/24036988.html.
Texto completoTheden-Ringl, Fenja. "Common cores in the high country. The archaeology and environmental history of the Namadgi Ranges". Phd thesis, 2018. http://hdl.handle.net/1885/149482.
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