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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
81

Late-Stage Peptide Diversification via Transition Metal-Catalyzed C─H Activation

Wang, Wei 17 September 2020 (has links)
No description available.
82

Anaerobic Co-Digestion of Algal Biomass and a Supplemental Carbon Source Material to Produce Methane

Soboh, Yousef 01 May 2015 (has links)
Algae that are grown in wastewater treatment lagoons could be an important substrate for biofuel production; however, the low C/N ratio of algae is not conducive to anaerobic digestion of algae with economically attractive methane production rates. Increasing the C/N ratio in anaerobic, laboratory scale, batch reactors by blending algal biomass with sodium acetate resulted i increased methane production rates as the C/N ratio increased. The highest amount of methane was produced when the C/N was 21/1. When the C/N was 24/1, the biogas production rate decreased. Batch experiments were done to evaluate the effect of optimizing the C/N ratio on methane production from algae and to identify the most essential information needed to conduct research on co-digestion of algal biomass using the continuous, high-rate, up-flow anaerobic sludge blanket (UASB) reactor system. Based on the results obtained from batch reactor experiments, anaerobic co-digestion of algal biomass, obtained by continuous centrifugation from the Logan City, Utah, 5th stage wastewater treatment lagoon, and sodium acetate was conducted using laboratory scale UASB reactors with the C/N ratio in the feedstock adjusted to 21/1. Duplicate, 34 L UASB reactor systems were built of poly(methyl methacrylate). Both reactors were seeded with 11 L of anaerobic sediment from the 3rd stage lagoon. The pH of the feedstock was adjusted to the neutral range. The feedstock was initially introduced at a low organic loading rate of 0.9 g/L.d with a hydraulic retention time (HRT) of 7.2 days and then increased up to 5.4 g/L.d and a HRT of 5.5 days. These organic loading rates corresponded to an initial influent chemical oxygen demand (COD) of 6.25 g/L and increased to 27.2 g/L. Methane production increased from 270 mL/g to 349 mL/g COD biodegraded. COD removal efficiency was 80% and biogas methane composition was 90% at steady state. Algal biomass contributed 33-50% of the COD in the feed stock depending on the COD of the algae paste from centrifugation. The shortest HRT at which steady state was not affected was 5.5 days. At lower HRT all monitored parameters showed a slight decrease after the 75th day of operation.
83

Synthesis and properties of d6 metal complexes of bidentate and tridentate ‘super donor’ ligands

Pal, Amlan Kumar 03 1900 (has links)
La polyvalence de la réaction de couplage-croisé C-N a été explorée pour la synthèse de deux nouvelles classes de ligands: (i) des ligands bidentates neutres de type N^N et (ii) des ligands tridentates neutres de type N^N^N. Ces classes de ligands contiennent des N-hétérocycles aromatiques saturés qui sont couplés avec hexahydropyrimidopyrimidine (hpp). Les ligands forment de cycles à six chaînons sur la coordination du centre Ru(II). Ce fait est avantageux pour améliorer les propriétés photophysiques des complexes de polypyridyl de Ru(II). Les complexes de Ru(II) avec des ligands bidentés ont des émissions qui dépendent de la basicité relative des N-hétérocycles. Bien que ces complexes sont électrochimiquement et photophysiquement attrayant, le problème de la stereopurité ne peut être évité. Une conception soigneuse du type de ligand nous permet de synthétiser un ligand bis-bidentate qui est utile pour surmonter le problème de stereopurité. En raison de la spécialité du ligand bis-bidentate, son complexe diruthénium(II,II) présente une grande diastéréosélectivité sans séparation chirale. Alors que l'unité de hpp agit comme un nucléophile dans le mécanisme de C-N réaction de couplage croisé, il peut également agir en tant que groupe partant, lorsqu'il est activé avec un complexe de monoruthenium. Les complexes achiraux de Ru(II) avec les ligands tridentés présentent des meilleures propriétés photophysiques en comparason avec les prototypes [Ru(tpy)2]2+ (tpy = 2,2′: 6′, 2′′-terpyridine). L’introduction de deux unités de hpp dans les ligands tridentates rend le complexe de Ru(II) en tant que ‘absorbeur noir’ et comme ‘NIR émetteur’ (NIR = de l’anglais, Near Infra-Red). Cet effet est une conséquence d'une meilleure géométrie de coordination octaédrique autour de l'ion Ru(II) et de la forte donation sigma des unités hpp. Les complexes du Re(I) avec des ligands tridentates présentent un comportement redox intéressant et ils émettent dans le bleu. L'oxydation quasi-réversible du métal est contrôlée par la donation sigma des fragments hpp, tandis que la réduction du ligand est régie par la nature électronique du motif N-hétérocycle central du ligand lui-même. Cette thèse presente également l'auto-assemblage des métal-chromophores comme ‘métallo-ligands’ pour former des espèces supramoléculaires discretes utilisant des complexes neutres. Les synthèses et propriétés des métaux-chromophores précités et les supramolécules sont discutées. / The versatility of C-N cross coupling reactions has been explored for the synthesis of two novel classes of ligands : (i) neutral bidentate N^N ligands and (ii) neutral tridentate N^N^N ligands. Both classes of ligands contain saturated aromatic N-heterocycles coupled with the unsaturated hexahydropyrimidopyrimidine (hpp) unit. The ligands form six-membered chelate rings upon coordination to a Ru(II) center. This fact is advantageous to improve the photophysical properties of Ru(II)-polypyridyl complexes. Ru(II) complexes of bidentate ligands can act as red-emitters. The red-emission is dependent on the relative basicity of the N-heterocycles. While these complexes are electrochemically and photophysically appealing, the problem of stereopurity can not be avoided. Careful ligand design affords bis-bidentate ligand that is useful to overcome the problem of stereopurity. Due to the speciality of this bis-bidentate ligand, its diruthenium(II,II) complex exhibits high diastereoselectivity without any chiral separation. While the hpp unit acts as a nucleophile in the mechanism of C-N cross coupling reaction, it can also act as a leaving group when activated as a monoruthenium complex. Achiral Ru(II) complexes of the tridentate ligands display improved photophysical properties over the prototype complex [Ru(tpy)2]2+ (tpy = 2,2’:6’,2’’-terpyridine). Introduction of two hpp units in the tridentate ligands renders the Ru(II) complex into a ‘black absorber’ and a ‘NIR emitter’ (NIR = Near Infra-Red). This fact is a consequence of better octahedral geometry around the Ru(II) ion and strong sigma-donation from the hpp units. The blue-emitting Re(I) complexes of the tridentate ligands also exhibit interesting redox behavior. The metal-based quasi-reversible oxidation is controlled by the sigma-donation from the hpp moieties, while the ligand-based reduction is governed by the electronic nature of the central N-heterocycle of the same ligand moiety. This thesis also incorporates self-assembly of metal-chromophores as ‘metallo-ligands’ to form discrete supramolecular species using neutral metal-complexes. The syntheses and properties of the aforesaid metal-chromophores and the supramolecules are discussed.
84

Complexes NCN de Ni(II) et Ni(III) : synthèse, caractérisation et rôle dans le mécanisme de couplage C-O, C-N et C-halogènes

Cloutier, Jean-Philippe 09 1900 (has links)
No description available.
85

Reconstrução paleoambiental (vegetação e clima) no Parque Estadual da Ilha do Cardoso - SP durante o Quaternário tardio / Palaeoenvironmental reconstruction in the parque Estadual da Ilha do Cardoso, São Paulo State during the late Quaternary

Vidotto, Elaine 30 June 2008 (has links)
Este estudo foi desenvolvido no Parque Estadual da Ilha do Cardoso (PEIC) e no Parque Estadual Carlos Botelho (PECB), na região sudeste do Brasil. A área é caracterizada pela presença de vegetação nativa de Floresta Atlântica de Encosta e no caso do PEIC, também por Restinga e vegetação de manguezal. Foram coletadas amostras de solos a partir de trincheiras ou tradagens, e amostras em dois mangues, Sítio Grande e do rio Jacariu. Análises isotópicas (12C, 13C, 14C, 14N, 15N) e biológicas (palinologia, diatomologia) foram utilizadas nesse estudo para entender a história da paleovegetação da região durante do Pleistoceno tardio e o Holoceno, assim como suas relações com as mudanças climáticas. Os dados isotópicos (\'delta\'13C, 14C) da matéria orgânica dos solos (MOS) em dois pontos do PEIC mostraram valores de \'delta\'13C característicos de plantas C3 (aproximadamente -27,0%o), indicando a presença de vegetação de floresta nos últimos 10.800 anos AP. Em três pontos (CB1, CB2 e TURVI) do PECB os dados isotópicos (\'delta\'13C) da MOS indicaram a presença de plantas C3 em todo o perfil analisado. Nos pontos TOR e FAZ os valores de \'delta\'13C foram mais enriquecidos (entre -20,9%o e -23,5%o) nas camadas mais profundas, indicando a presença de uma vegetação menos densa que a atual, com uma provável presença de plantas C3 e C4, no período de aproximadamente 25.000 a 15.000 anos AP, sugerindo a presença de um clima mais seco. De aproximadamente 15.000 anos AP até o presente um empobrecimento isotópico (até -28,0%o) foi observado indicando a expansão da floresta, provavelmente associada à presença de um clima mais úmido que o período anterior. No mangue Sítio Grande os valores de \'delta\'13C foram mais empobrecidos (até -28,0%o) entre aproximadamente 40.000 e 19.000 anos AP. Os valores mais empobrecidos de \'delta\'13C associados com altos teores de carbono (até 40%) e da razão C/N (até 130) indicaram a presença de uma floresta na atual área do mangue e o abaixamento do nível relativo do mar. A presença de pólen de Ilex, Alchornea, Weinmannia, Rapanea, Symplocos, Drimys e Podocarpus sugerem a presença de uma floresta característica de clima mais frio e úmido que o atual entre 40.000 e 19.000 anos AP. Entre 19.000 e 2.200 anos AP observou-se um hiato sedimentar (provavelmente erosivo), atribuído a prováveis atividades neotectônicas ocorridas na região. Os valores mais enriquecidos de \'delta\'13C (aproximadamente -26,0%o e -24,0%o) associados com menores valores de COT (entre 0,3% e 6,0%) e razão C/N (entre 2 e 27), juntamente com a presença de diatomáceas marinhas, indicaram a presença do mangue e o retorno da linha de costa na posição atual na região desde pelo menos 2.200 anos AP. No mangue do rio Jacariu os resultados de \'delta\'13C apresentaram valores entre -24,0%o e -26,0%o. Os valores de COT e da razão C/N associados com os valores de \'delta\'13C indicaram uma mistura de plantas C3 e fitoplâncton na composição da matéria orgânica. As diatomáceas encontradas foram características de ambiente estuarino-lagunar e estiveram presentes aproximadamente nos últimos 1.500 anos AP / This study was developed in the Parque Estadual da Ilha do Cardoso (PEIC) and Parque Estadual Carlos Botelho (PECB), in the southeastern region of Brazil. The area is characterized by the presence of native vegetation of Atlantic Forest and in the case of PEIC, also for Restinga and mangrove vegetation. Soil samples were collected from trenches and by drilling. Were collected two cores in the Sítio Grande and Jacariu mangroves. Isotope (12C, 13C, 14C, 14N, 15N) and biological (pollen and diatoms analysis) tools were used in the study to understand the paleovegetation history of the region during the late Pleistocene and Holocene and its relation to climatic changes. The soil isotope data (\'delta\'13C) of soil organic matter (SOM) at two locations in the PEIC area showed values characteristics of C3 plants (approximately -27,0%o), indicating the presence of forest vegetation during the last 10.800 years BP. In three locations (CB1, CB2 and TURVI) in the PECB area the isotope data (\'delta\'13C) of SOM indicated the presence of C3 plants in the whole profile. In the locations TOR and FAZ the values were more enriched (from -20,9%o e -23,5%o) in the deeper horizons, indicating the presence of a less dense vegetation than the present, with a probable mixture of \'delta\'13C, 14C plants, in the period of approximately 25.000 to 15.000 years BP, suggesting the presence of a drier climate. From 15.000 years BP to the present, a isotopic depletion (até -28,0%o) was observed and associated with the expansion of the forest, probably associated to the presence of a more humid climate than the previous period. In the Sítio Grande mangrove the \'delta\'13C values were more depleted (approximately -28,0%o) from 40.000 to 19.000 years BP. The higher values of total organic carbon (40%) and C/N ratios (130), associated with more depleted \'delta\'13C values observed during this period indicated the predominance of C3 land plants in the location at present occupied by the mangrove and the decrease of the relative sea level. The presence of pollen of Ilex, Alchornea, Weinmannia, Rapanea, Symplocos, Drimys and Podocarpus during the period of 40.000 to 19.000 years BP suggest the presence of a colder and humid climate than today. From 19.000 to 2.200 years BP a sedimentary hiatus (probably erosive) was observed, attributed to a neotectonic activity in the studied area. The presence of mangrove since at least 2.200 years BP in its present position and the return of the marine cost line is associated with the values of COT (from 0,3% to 6%) and C/N ratio (from 2 to 27), more enriched \'delta\'13C values (from approximately -26,0%o e -24,0%o) and the presence of marine diatoms. In the Jacariu mangrove the \'delta\'13C results associated with the smallest values of total organic and C/N ratios, probably indicated a mixture of marine phytoplankton and C3 land plants in the composition of the organic matter. The marine diatoms were present approximately in the last 1.500 years BP and they are characteristics the estuarine site
86

Copper-Catalyzed Domino C-N Bond Formation for Synthesis of N-Containing Compounds (Benzimidazoles, Imidazoles, and Guanidines) - Approach toward Total Synthesis of Natural Product Raputindoles / Formation de Liaisons C-N Cupro-Catalysées Domino pour la Synthèse de Composés Azotés (Benzimidazoles, Imidazoles et Guanidines) - Approche vers la Synthèse Totale de Produits Naturels de la Famille des Raputindoles

Li, Jihui 24 July 2013 (has links)
Cette thèse est constituée de trois parties : 1) Le contexte bibliographique, 2) le développement de réactions domino cupro-catalysées et 3) une approche vers la synthèse totale des raputindoles.La première partie introduit d’abord le concept de réactions domino ainsi que leurs applications, puis les réactions catalysées par du cuivre permettant de former des liaisons C-N sont passées en revue en incluant les couplages de Ullmann, Goldberg et de Chan-Lam, les séquences d’activation oxydante de liaisons C-H/formation de liaison C-N, l’insertion de nitrènes et l’hydroamination de liaisons C-C multiples. En se basant sur ces réactions élémentaires permettant de former une liaison C-N unique, les développements récents de réactions domino sont ensuite détaillés.La deuxième partie peut être subdivisée en 3 sections : 1) la synthèse de benzimidazoles, 2) la synthèse d’imidazoles and 3) la synthèse de guanidines. Un rappel des méthodes existantes pour la synthèse de ces motifs est proposé dans chaque section. Notre travail, basé sur la formation de liaisons C-N multiples selon une séquence cupro-catalysée domino, est ensuite détaillé. Celui-ci nous a permis d’aboutir au développement de voies d’accès aux benzimidazoles, en utilisant une réaction séquentielle catalysée par du cuivre en présence d’oxygène à partir d’acides boroniques et d’amidines, à la synthèse d’imidazoles par une réaction de di-amination d’alcynes vrai par des amidines et à l’obtention de guanidines et de 2-aminobenzimidines par une réaction à 3 composant. Ces réactions domino montrent une bonne efficacité et permettent d’assembler des hétérocycles à partir de précurseurs aisément accessibles.La dernière partie est consacrée à la synthèse des raputindoles. La structure, les activités et les réactions clé pour la construction de ces alcaloïdes sont discuté d’abord, nous amenant à proposer une rétrosynthèse pour accéder à ces molécules. Les réactions qui ont retenues notre attention pour construire ces molécules sont une annelation [3+2] irido-catalysée d’acides o-formylarylboronique et de 1,3-diènes, la synthèse de Leimgruber-Batcho pour obtenir des indoles et une séquence d’alkylboration-protodéboration. A partir de cela 3 stratégies ont été évaluées, montrant que l’accès à ce type de composé naturel est envisageable en combinant ces étapes. / This thesis consists in three parts: bibliographic background, copper-catalyzed reactions for synthesis of N-containing compounds, approach to the synthesis of raputindoles.The first part introduces the domino reactions and their applications, then, copper-mediated reactions for construction of C-N bond formation are reviewed including Ullmann, Goldberg and Chan-Lam coupling, oxidative C-H activation/C-N formation, insertion of nitrenes and carbenoids, and hydroamination of multi-C-C bonds. This can be used as guides to design domino reaction. Following these copper-mediated single C-N bond formation reactions, recent developments of copper-catalyzed domino reactions for synthesis of heterocycles are described.The second part can be divided into three sections: 1) synthesis of benzimidazoles, 2) synthesis of imidazoles and 3) synthesis of guanidines. Each section summarizes the existing methods used for their synthesis. Following it, our synthetic work involving copper-catalyzed C-N bond formation domino reactions is discussed in detail. Our objectives include the synthesis of benzimidazoles through copper-catalyzed sequential reaction of benzamidines and boronic acids, synthesis of imidazoles via copper-catalyzed domino reaction of benzamidines and acetylenes, and synthesis of guanidines and 2-aminobenzimidazoles by Cu-catalyzed three-component reaction of cyanamides, boronic acids and amines. These copper-catalyzed domino reactions show high efficiencies from readily available and simple starting materials.The last part is about the total synthesis of raputindoles. The structure and bioactivities of raputindoles and key reactions for the total synthesis of raputindoles are introduced first, the synthetic strategies are then proposed on basis of relative synthetic methods. The key reactions we use for the synthesis of raputindoles are iridium catalyzed [3+2] annulation of o-formylarylboronic acids and 1,3-dienes, Leimgruber-Batcho indole synthesis, transition-metal catalyzed SN2 substitution and alkylborylation-protondeborylation. According to the three strategies we proposed, lots of relative reactions were investigated. The results show that it is possible to synthesize the raputindole molecules based on the iridium catalyzed [3+2] annulation of 2-formylarylboronic acids and 1,3-dienes.
87

Substitution nucléophile aromatique des acides benzoïques et naphtoïques ortho fluorés/méthoxylés non protégés (SNArAB) par les bases fortes (RLi, RMgX et R2NLi) en l'absence de catalyseur métallique

Belaud-Rotureau, Mickaël 25 June 2010 (has links) (PDF)
Dans le cadre d'un projet général d'étude de la réactivité des acides benzoïques non protégés avec les bases fortes, la réaction de substitution nucléophile aromatique des acides benzoïques ortho-fluorés et ortho-méthoxylés (SNArAB) avec les organolithiens et les réactifs de Grignard est étudiée pour la première fois de façon systématique. Une revue de la littérature de la réaction de Meyers (>1994) a été faite. Afin de réduire le taux d'addition 1,2 de l'organométallique sur le carboxylate conduisant à la formation de cétones, un groupe TMS a été introduit en ortho (C6) du carboxylate. Lors de la préparation des acides 2-méthoxy-6-triméthylsilylbenzoïque et 2-fluoro-6-triméthylsilylbenzoïques, il a été découvert que la séquence [échange Br-Li/piégeage par D2O] est compétitive avec l'attaque directe de n-BuLi sur D2O. De façon intéressante, la présence d'un fluor en C6 rend le carboxylate totalement inerte vis-à-vis des organolithiens. L'acide 2,6-difluorobenzoïque conduit aux produits d'ipso-C2-substitution sans formation de cétones alors qu'une décarboxylation partielle est observée avec l'acide 2,6-diméthoxybenzoïque. La réaction SNArAB des acides benzoïques et naphtoïques ortho-fluorés et orthométhoxylés avec les amidures de lithium a ensuite été étudiée. Cette réaction conduit en une étape à des acides anthraniliques et ne requiert pas protection et déprotection de la fonction acide carboxylique. L'utilisation d'un excès de LiNMeBn conduit à un dioxindole pour lequel un mécanisme de formation est proposé. Enfin, une étude préliminaire de la réaction de métalation des acides 2- et 3 (tertbutoxycarbonylamino) benzoïques par les bases alkyllithiées a été réaliséé. Il n'a pas été possible de former les trianions correspondants. Cependant, lorsque l'acide 2-(tertbutoxycarbonylamino) benzoïque est traité par LTMP en présence de TMSCl dans les conditions de piégeage interne (ISQ), l'acide 2-(tert-butoxycarbonylamino)-6- (triméthylsilyl)benzoïque est formé avec un rendement de 76%.
88

Nutrient release and cycling in the soils of a continental lodgepole pine (Pinus contorta Doug.) ecosystem, Bootleg Mountain, B.C.

Lamberts, Jill S. 13 October 2005 (has links)
Nutrient dynamics in a lodgepole pine forest at Bootleg Mountain, B.C., were investigated through the sampling of soil, snow and groundwater in six one-ha blocks. Nitrogen (NO3-, NH4+, TIN, TDN, TN), phosphorus (PO43-, TDP, TP), and DOC were analyzed in addition to N mineralization and nitrification. Position and dispersion statistics were computed for each variable and correlations (Pearson and Spearman) were computed for each pair of variables. The overall heterogeneities of soil, snow, and groundwater were generally lower between 1-ha blocks than between plots. Productivity in the soil was generally N-limited with low input from snow precipitation. Very little N leached from soil to groundwater. Phosphorus contents were highly variable and were the limiting nutrient in the groundwater. Rates of net and gross N mineralization and nitrification were determined using buried bags and 15N isotope dilutions. Gross rates were greater than net rates and nitrification was low relative to high immobilization rates. The N cycle appears to be tightly regulated, thus further study will be needed to monitor the impact of harvesting on N cycling.
89

Nutrient release and cycling in the soils of a continental lodgepole pine (Pinus contorta Doug.) ecosystem, Bootleg Mountain, B.C.

Lamberts, Jill S. 13 October 2005 (has links)
Nutrient dynamics in a lodgepole pine forest at Bootleg Mountain, B.C., were investigated through the sampling of soil, snow and groundwater in six one-ha blocks. Nitrogen (NO3-, NH4+, TIN, TDN, TN), phosphorus (PO43-, TDP, TP), and DOC were analyzed in addition to N mineralization and nitrification. Position and dispersion statistics were computed for each variable and correlations (Pearson and Spearman) were computed for each pair of variables. The overall heterogeneities of soil, snow, and groundwater were generally lower between 1-ha blocks than between plots. Productivity in the soil was generally N-limited with low input from snow precipitation. Very little N leached from soil to groundwater. Phosphorus contents were highly variable and were the limiting nutrient in the groundwater. Rates of net and gross N mineralization and nitrification were determined using buried bags and 15N isotope dilutions. Gross rates were greater than net rates and nitrification was low relative to high immobilization rates. The N cycle appears to be tightly regulated, thus further study will be needed to monitor the impact of harvesting on N cycling.
90

Reconstrução paleoambiental (vegetação e clima) no Parque Estadual da Ilha do Cardoso - SP durante o Quaternário tardio / Palaeoenvironmental reconstruction in the parque Estadual da Ilha do Cardoso, São Paulo State during the late Quaternary

Elaine Vidotto 30 June 2008 (has links)
Este estudo foi desenvolvido no Parque Estadual da Ilha do Cardoso (PEIC) e no Parque Estadual Carlos Botelho (PECB), na região sudeste do Brasil. A área é caracterizada pela presença de vegetação nativa de Floresta Atlântica de Encosta e no caso do PEIC, também por Restinga e vegetação de manguezal. Foram coletadas amostras de solos a partir de trincheiras ou tradagens, e amostras em dois mangues, Sítio Grande e do rio Jacariu. Análises isotópicas (12C, 13C, 14C, 14N, 15N) e biológicas (palinologia, diatomologia) foram utilizadas nesse estudo para entender a história da paleovegetação da região durante do Pleistoceno tardio e o Holoceno, assim como suas relações com as mudanças climáticas. Os dados isotópicos (\'delta\'13C, 14C) da matéria orgânica dos solos (MOS) em dois pontos do PEIC mostraram valores de \'delta\'13C característicos de plantas C3 (aproximadamente -27,0%o), indicando a presença de vegetação de floresta nos últimos 10.800 anos AP. Em três pontos (CB1, CB2 e TURVI) do PECB os dados isotópicos (\'delta\'13C) da MOS indicaram a presença de plantas C3 em todo o perfil analisado. Nos pontos TOR e FAZ os valores de \'delta\'13C foram mais enriquecidos (entre -20,9%o e -23,5%o) nas camadas mais profundas, indicando a presença de uma vegetação menos densa que a atual, com uma provável presença de plantas C3 e C4, no período de aproximadamente 25.000 a 15.000 anos AP, sugerindo a presença de um clima mais seco. De aproximadamente 15.000 anos AP até o presente um empobrecimento isotópico (até -28,0%o) foi observado indicando a expansão da floresta, provavelmente associada à presença de um clima mais úmido que o período anterior. No mangue Sítio Grande os valores de \'delta\'13C foram mais empobrecidos (até -28,0%o) entre aproximadamente 40.000 e 19.000 anos AP. Os valores mais empobrecidos de \'delta\'13C associados com altos teores de carbono (até 40%) e da razão C/N (até 130) indicaram a presença de uma floresta na atual área do mangue e o abaixamento do nível relativo do mar. A presença de pólen de Ilex, Alchornea, Weinmannia, Rapanea, Symplocos, Drimys e Podocarpus sugerem a presença de uma floresta característica de clima mais frio e úmido que o atual entre 40.000 e 19.000 anos AP. Entre 19.000 e 2.200 anos AP observou-se um hiato sedimentar (provavelmente erosivo), atribuído a prováveis atividades neotectônicas ocorridas na região. Os valores mais enriquecidos de \'delta\'13C (aproximadamente -26,0%o e -24,0%o) associados com menores valores de COT (entre 0,3% e 6,0%) e razão C/N (entre 2 e 27), juntamente com a presença de diatomáceas marinhas, indicaram a presença do mangue e o retorno da linha de costa na posição atual na região desde pelo menos 2.200 anos AP. No mangue do rio Jacariu os resultados de \'delta\'13C apresentaram valores entre -24,0%o e -26,0%o. Os valores de COT e da razão C/N associados com os valores de \'delta\'13C indicaram uma mistura de plantas C3 e fitoplâncton na composição da matéria orgânica. As diatomáceas encontradas foram características de ambiente estuarino-lagunar e estiveram presentes aproximadamente nos últimos 1.500 anos AP / This study was developed in the Parque Estadual da Ilha do Cardoso (PEIC) and Parque Estadual Carlos Botelho (PECB), in the southeastern region of Brazil. The area is characterized by the presence of native vegetation of Atlantic Forest and in the case of PEIC, also for Restinga and mangrove vegetation. Soil samples were collected from trenches and by drilling. Were collected two cores in the Sítio Grande and Jacariu mangroves. Isotope (12C, 13C, 14C, 14N, 15N) and biological (pollen and diatoms analysis) tools were used in the study to understand the paleovegetation history of the region during the late Pleistocene and Holocene and its relation to climatic changes. The soil isotope data (\'delta\'13C) of soil organic matter (SOM) at two locations in the PEIC area showed values characteristics of C3 plants (approximately -27,0%o), indicating the presence of forest vegetation during the last 10.800 years BP. In three locations (CB1, CB2 and TURVI) in the PECB area the isotope data (\'delta\'13C) of SOM indicated the presence of C3 plants in the whole profile. In the locations TOR and FAZ the values were more enriched (from -20,9%o e -23,5%o) in the deeper horizons, indicating the presence of a less dense vegetation than the present, with a probable mixture of \'delta\'13C, 14C plants, in the period of approximately 25.000 to 15.000 years BP, suggesting the presence of a drier climate. From 15.000 years BP to the present, a isotopic depletion (até -28,0%o) was observed and associated with the expansion of the forest, probably associated to the presence of a more humid climate than the previous period. In the Sítio Grande mangrove the \'delta\'13C values were more depleted (approximately -28,0%o) from 40.000 to 19.000 years BP. The higher values of total organic carbon (40%) and C/N ratios (130), associated with more depleted \'delta\'13C values observed during this period indicated the predominance of C3 land plants in the location at present occupied by the mangrove and the decrease of the relative sea level. The presence of pollen of Ilex, Alchornea, Weinmannia, Rapanea, Symplocos, Drimys and Podocarpus during the period of 40.000 to 19.000 years BP suggest the presence of a colder and humid climate than today. From 19.000 to 2.200 years BP a sedimentary hiatus (probably erosive) was observed, attributed to a neotectonic activity in the studied area. The presence of mangrove since at least 2.200 years BP in its present position and the return of the marine cost line is associated with the values of COT (from 0,3% to 6%) and C/N ratio (from 2 to 27), more enriched \'delta\'13C values (from approximately -26,0%o e -24,0%o) and the presence of marine diatoms. In the Jacariu mangrove the \'delta\'13C results associated with the smallest values of total organic and C/N ratios, probably indicated a mixture of marine phytoplankton and C3 land plants in the composition of the organic matter. The marine diatoms were present approximately in the last 1.500 years BP and they are characteristics the estuarine site

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