In recent years, there has been increasing concern with respect to the large dependence across the globe on nonrenewable energy sources, such as fossil fuels. Ethanol has been explored, however, in alleviating this problem; cellulose, a polymer of glucose molecules, is a precursor to this potentially useful biofuel. However, the strength and rigidity of the cellulose structure has proven to be a difficult obstacle to overcome in this multistep synthesis. Harsh conditions are required, often including concentrated sulfuric acid and extremely high temperatures, to complete hydrolysis to a useful extent. In this work, the hydrolysis of cellulose was performed with acidic hydrogen molybdenum bronze in the form of XPell™ R by Xplosafe in place of sulfuric acid. By analyzing total organic carbon present in hydrolyzed samples (after 2 hours) using persulfate oxidation and colorimetric measurements, results were obtained showing that hydrogen molybdenum bronze is successful in catalyzing the hydrolysis of cellulose in comparison to hydrolysis completed in water alone. The values that were obtained in this analysis are as follows: 160 ± 20 ppt/mol at 40 °C, 180 ± 20 ppt/mol at 60 °C, 180 ± 30 ppt/mol at 80 °C, and 280 ± 40 ppt/mol at 100 °C. This determination shows that the catalytic ability of this acid increases with increasing temperature. Hydrogen molybdenum bronze is a useful candidate to explore in biofuel synthesis from cellulose. Comparison to sulfuric acid will be completed in future tests. This method is currently being used to pursue conversion of hydrolyzed cellulose to ethanol using yeast.

The purpose of this study was to characterize the leachate from a landfill in Pennsylvania that had been pretreated by activated sludge and propose the most efficient treatment for this effluent. These samples had been pretreated in a sequencing batch reactor that also was operated to remove nitrogen by nitrification/denitrification. The SBR samples were found to have low BOD, high COD, high TOC and a very low BOD/COD ratio. These SBR decant samples have poor UV transmittance and hence quench UV light. Five treatment methods were evaluated, coagulation, ultrafiltration, combined coagulation/ultrafiltration, combined ultrafiltration/oxidation and combined filtration/fentons. These processes were tested for their ability to remove BOD and TOC and also to evaluate the improvement in UV transmittance. It was found that coagulation; Ultrafiltration and Ultrafiltration combined with coagulation do not work in improving the transmittance properties though there is a significant BOD and TOC removal with these processes. Ultrafiltration combined with oxidation was found to work the best in terms of TOC removal. In this study, four oxidants, KMnO?, H?O?, NaOCl and Fenton's reagent were used. It was observed that Fenton's reagent was capable of removing 90% TOC at a dose of 1g/L each of iron salt and hydrogen peroxide at a pH of 4.5. Since Fentons reagent was found to be the most effective method, hence, efforts were made to optimize the oxidation process with Fenton's. The two parameters which were studied were the initial pH and the chemical dosage. The initial pH was varied from a value of 2.5 to 6.5. The range of iron salt and peroxide dose used was from 0.05 to 0.1 g/L. Additional studies were conducted using samples filtered through a 0.45 um filter and oxidized with Fenton's reagent. The Fenton's process for oxidation of filtrates from the 0.45?m filter was also optimized with respect to pH and chemical dosage to determine the most economical operating conditions. The maximum transmittance of 57% was obtained for an iron dose of 0.075 g/L and a peroxide dose of 0.075 g/L at a pH of 4.5. This is in comparison to the transmittance of unoxidized 1K ultrafiltrate which was found to be 21.5%. There was a significant difference in the performance of 1K and 0.45um filtrates in terms of TOC removal and percentage transmittance. The oxidation process for improving the UV transmittance of leachate can therefore be economically optimized depending upon the desired efficiency by varying the operational parameters. / Master of Science

Η λεπτομερής ιζηματολογική ανάλυση των αποθέσεων της τομής Μακρυλιά, έδειξε την ύπαρξη τουλάχιστον 5 κύκλων ιζηματογένεσης με αυξανόμενο προς τα πάνω κοκκομετρικό μέγεθος που αναπτύχτηκαν σε ένα περιβάλλον υφαλοκρηπίδας. Η κύρια λιθολογία είναι αμμούχος πηλός και τα ιζήματα μεταφέρθηκαν ως ομογενές αιώρημα. Το ποσοστό του ανθρακικού ασβεστίου είναι χαμηλό και τείνει αυξανόμενο προς τα πιο αδρομερή κλάσματα. Το ποσοστό του οργανικού υλικού έδειξε την παρουσία αρκετών δειγμάτων με αυξημένο οργανικό υλικό προτείνοντας την ύπαρξη εν δυνάμει μητρικών πετρωμάτων για την γένεση υδρογονανθράκων. Η σχέση μεταξύ του ανθρακικού ασβεστίου και οργανικού υλικού είναι κύρια αρνητική προτείνοντας ανοξικές συνθήκες. Η βιοστρωματογραφική ανάλυση έδειξε Πλειοκαινική ηλικία των ιζημάτων που αποτέθηκαν σε εναλλασσόμενες οξικές – ανοξικές συνθήκες. Από τα παραπάνω αποτελέσματα και περνώντας υπόψη τα υπάρχοντα αποτελέσματα των ιζημάτων που περιβάλλουν την περιοχή μελέτης φαίνεται πως οι μελετηθείσες αποθέσεις συγκεντρώθηκαν σε μια ρηχή με ήσυχα νερά ενδο-ορεινή λεκάνη στα περιθώρια της κύριας λεκάνης της Ιεράπετρας. / Detailed sedimentological analysis, in Makrylia cross-section deposits, showed at least five coarsening-upward cycles developed in a shelf environment. The main lithology is sandy silt and sediments transported as homogenous suspension in a low energy environment that deposited in a shallow water basin. Calcium carbonate (CaCO3) is low and tends to increase to the coarse-grained clasts. Organic carbon (TOC) ratio showed the presence of many high content samples in TOC suggesting potential hydrocarbon source rocks. There is mostly a negative relation between CaCO3 and TOC introducing generally anoxic conditions. Biostratigraphy analysis showed a Pliocene age for the studied deposits in alternating conditions with oxic- anoxic events. According to the above results and taking into account previous results from the surrounding sediments it seems that studied deposits accumulated in a shallow, low energy, intra-mountain basin at the margins of the main Ierapetra basin.

O presente trabalho teve como objetivo avaliar a eficiência de pós-filtros adsorvedores constituídos de Carvão Ativado Granular (CAG) na remoção de compostos orgânicos precursores e na formação de subprodutos da desinfecção, em particular dos trialometanos (THM) na Estação de Tratamento de Água Alto da Boa Vista (ETA ABV), abastecida por reservatórios de água bruta com elevado grau de eutrofização. Os ensaios foram conduzidos em ETA Piloto composta por tanque de reservação de água filtrada, ozonizador, tanque de reservação de água ozonizada e 4 pós-filtros adsorvedores, sendo duas unidades dotadas de CAG de origem mineral e duas unidades dotadas de CAG de origem vegetal. Os filtros foram operados em paralelo, sendo que duas colunas foram alimentadas com água filtrada da ETA ABV (Filtro F3 CAG de origem mineral e Filtro F4 CAG de origem vegetal) e as outras duas alimentadas com água filtrada e ozonizada (Filtro F1 CAG de origem mineral e Filtro F2 CAG de origem vegetal). A avaliação da remoção de compostos orgânicos precursores e formação de subprodutos da desinfecção foi feita através de análises de carbono orgânico total (COT), UV-254 nm e formação de THM. A análise dos resultados gerados de julho de 2007 a dezembro de 2008 permitiu concluir que 93% do THM é formado nas primeiras 24 horas de contato da amostra com o cloro, simulando a pós cloração e pós alcalinização da ETA ABV. O processo de oxidação por ozônio não foi efetivo na remoção de THM instantâneo, visto que a média dos 38 valores de THM instantâneo para a água filtrada (17,8 ± 5,6 g/L) foi igual a média obtida para o THM instantâneo na água ozonizada. A remoção de THM pelos filtros de CAG foi mais significativa nos primeiros três meses de operação do sistema, apresentando remoção de 80% para os filtros com CAG de origem mineral e 70% para os filtros com CAG de origem vegetal, a partir do quarto mês de operação do sistema a remoção de THM caiu para um valor médio de 34%, o que mostra uma iminente saturação do leito adsorvedor. Os pós-filtros adsorvedores constituídos de CAG de origem mineral apresentaram melhor comportamento com respeito a remoção de THM e COT quando comparado com os pós-filtros dotados de CAG de origem vegetal. / The main purpose of this work was to evaluate the performance of a Granular Activated Carbon (GAC) post-filter adsorbers in the removal of organic precursors and in the formation of disinfection byproducts, especially trihalomethanes (THM) in Alto da Boa Vista Water Treatment Plant (ABV WTP), which takes raw water from a highly eutrophized reservoirs. The tests was conducted on a Pilot WTP composed of filtered water tank, ozonator, ozonized water tank, and four post-filter adsorbers: two units with mineral GAC media and two units with vegetal GAC media. The filters were operated in parallel, with two columns fed with filtered water from ABV WTP (F3 Filter mineral GAC and F4 Filter vegetal GAC) and the other fed with ozonized water (F1 Filter mineral GAC and F2 Filter vegetal GAC). The evaluation of the removal of organic precursors and the formation of disinfection byproducts was made through analysis of Total Organic Carbon (TOC), UV-254 nm and THM formation. The results generated from July 2007 to December 2008 showed that 93% of THM is formed in the first 24 hours of contact with the chlorine in the sample, simulating the post chlorination and post alkalinization of ABV WTP in samples of filtered water, ozonized water, and post-filter adsorbers effluent. Ozone oxidation process was not effective in removing THM. Was found the same instantaneous THM values in the filtered water (17.8 g/L± 5.6 g/L) and in the ozonized water. During the first three months of post-filter adsorber operation, THM removal efficiencies were around 80% for F1 and F3 (mineral GAC media) and around 70% for F2 and F4 (vegetal GAC media). After four months of operation, THM removal efficiencies decreased to 34% average value, thus indicative of GAC saturation. Regarding THM and TOC removal efficacy, the mineral GAC performed better than the vegetal GAC.

O presente trabalho teve como objetivo avaliar a eficiência de pós-filtros adsorvedores constituídos de Carvão Ativado Granular (CAG) na remoção de compostos orgânicos precursores e na formação de subprodutos da desinfecção, em particular dos trialometanos (THM) na Estação de Tratamento de Água Alto da Boa Vista (ETA ABV), abastecida por reservatórios de água bruta com elevado grau de eutrofização. Os ensaios foram conduzidos em ETA Piloto composta por tanque de reservação de água filtrada, ozonizador, tanque de reservação de água ozonizada e 4 pós-filtros adsorvedores, sendo duas unidades dotadas de CAG de origem mineral e duas unidades dotadas de CAG de origem vegetal. Os filtros foram operados em paralelo, sendo que duas colunas foram alimentadas com água filtrada da ETA ABV (Filtro F3 CAG de origem mineral e Filtro F4 CAG de origem vegetal) e as outras duas alimentadas com água filtrada e ozonizada (Filtro F1 CAG de origem mineral e Filtro F2 CAG de origem vegetal). A avaliação da remoção de compostos orgânicos precursores e formação de subprodutos da desinfecção foi feita através de análises de carbono orgânico total (COT), UV-254 nm e formação de THM. A análise dos resultados gerados de julho de 2007 a dezembro de 2008 permitiu concluir que 93% do THM é formado nas primeiras 24 horas de contato da amostra com o cloro, simulando a pós cloração e pós alcalinização da ETA ABV. O processo de oxidação por ozônio não foi efetivo na remoção de THM instantâneo, visto que a média dos 38 valores de THM instantâneo para a água filtrada (17,8 ± 5,6 g/L) foi igual a média obtida para o THM instantâneo na água ozonizada. A remoção de THM pelos filtros de CAG foi mais significativa nos primeiros três meses de operação do sistema, apresentando remoção de 80% para os filtros com CAG de origem mineral e 70% para os filtros com CAG de origem vegetal, a partir do quarto mês de operação do sistema a remoção de THM caiu para um valor médio de 34%, o que mostra uma iminente saturação do leito adsorvedor. Os pós-filtros adsorvedores constituídos de CAG de origem mineral apresentaram melhor comportamento com respeito a remoção de THM e COT quando comparado com os pós-filtros dotados de CAG de origem vegetal. / The main purpose of this work was to evaluate the performance of a Granular Activated Carbon (GAC) post-filter adsorbers in the removal of organic precursors and in the formation of disinfection byproducts, especially trihalomethanes (THM) in Alto da Boa Vista Water Treatment Plant (ABV WTP), which takes raw water from a highly eutrophized reservoirs. The tests was conducted on a Pilot WTP composed of filtered water tank, ozonator, ozonized water tank, and four post-filter adsorbers: two units with mineral GAC media and two units with vegetal GAC media. The filters were operated in parallel, with two columns fed with filtered water from ABV WTP (F3 Filter mineral GAC and F4 Filter vegetal GAC) and the other fed with ozonized water (F1 Filter mineral GAC and F2 Filter vegetal GAC). The evaluation of the removal of organic precursors and the formation of disinfection byproducts was made through analysis of Total Organic Carbon (TOC), UV-254 nm and THM formation. The results generated from July 2007 to December 2008 showed that 93% of THM is formed in the first 24 hours of contact with the chlorine in the sample, simulating the post chlorination and post alkalinization of ABV WTP in samples of filtered water, ozonized water, and post-filter adsorbers effluent. Ozone oxidation process was not effective in removing THM. Was found the same instantaneous THM values in the filtered water (17.8 g/L± 5.6 g/L) and in the ozonized water. During the first three months of post-filter adsorber operation, THM removal efficiencies were around 80% for F1 and F3 (mineral GAC media) and around 70% for F2 and F4 (vegetal GAC media). After four months of operation, THM removal efficiencies decreased to 34% average value, thus indicative of GAC saturation. Regarding THM and TOC removal efficacy, the mineral GAC performed better than the vegetal GAC.

Several studies in high-latitude catchments have demonstrated the importance of near-stream riparian zones as hydrogeochemical hotspots with a substantial influence on stream chemistry. An adequate representation of the spatial variability of riparian-zone processes and characteristics is the key for modeling spatio-temporal variations of stream-water quality. This thesis contributes to current knowledge by refining landscape-analysis techniques to describe riparian zones and by introducing a conceptual framework to quantify solute exports from riparian zones. The utility of the suggested concepts is evaluated based on an extensive set of hydrometric and chemical data comprising measurements of streamflow, groundwater levels, soil-water chemistry and stream chemistry. Standard routines to analyze digital elevation models that are offered by current geographical information systems have been of very limited use for deriving hydrologically meaningful terrain indices for riparian zones. A model-based approach for hydrological landscape analysis is outlined, which, by explicitly simulating groundwater levels, allows better predictions of saturated areas compared to standard routines. Moreover, a novel algorithm is presented for distinguishing between left and right stream sides, which is a fundamental prerequisite for characterizing riparian zones through landscape analysis. The new algorithm was used to derive terrain indices from a high-resolution LiDAR digital elevation model. By combining these terrain indices with detailed hydrogeochemical measurements from a riparian observatory, it was possible to upscale the measured attributes and to subsequently characterize the variation of total organic-carbon exports from riparian zones in a boreal catchment in Northern Sweden. Riparian zones were recognized as highly heterogeneous landscape elements. Organic-rich riparian zones were found to be hotspots influencing temporal trends in stream-water organic carbon while spatial variations of organic carbon in streams were attributed to the arrangement of organic-poor and organic-rich riparian zones along the streams. These insights were integrated into a parsimonious modeling approach. An analytical solution of the model equations is presented, which provides a physical basis for commonly used power-law streamflow-load relations. / At the time of doctoral defense, the following papers were unpublished and had a status as follows: Paper 2: In press; Paper 4: Manuscript. / Swedish Research Council (VR, grant no. 2005-4289)

Freshwater bodies have been long observed to become browner within the northern hemisphere. This brownification, has made drinking water production difficult, since increased organic content in freshwaters requires higher dosages of chemicals during water treatment.  Changes in land use through increased industrial forestry, decreased sulphur deposition from reduced industrial emissions, changing patterns of hydrological and meteorological parameters resulting from climate change, including recently highlighted increase in iron concentrations have been proposed to explain brownification. Drained peat bogs are man-made source of brownifying substances, capable of causing brownification in the rivers and lakes where the water ends up. This research is aimed at investigating dissolved organic matter, total organic carbon, iron, phosphorous, nitrogen and colour in bog ditches draining into the Storån River and Lake Bolmen in southern Sweden, in order to answer these research questions: (1) What are the differences in the level of water quality parameters, pH, conductivity, temperature, DOM, TOC, total phosphorous, total nitrogen, Fe and colour, between bog ditches and Storån River? And what could be the outcome of Colour absorbance comparison, between bog ditches, Storån and lake Bolmen as a single control sample? (2) Is there any association among the different water quality parameters, pH, conductivity, temperature, DOM, TOC, total phosphorous, total nitrogen, Fe and colour within the bog ditch water? Water samples from bog ditches and their corresponding Storån River locations, were used in the analysis. DOM and flow showed significant differences, after statistical test for difference. Conductivity, DOM, total nitrogen and total phosphorous exhibited significant correlations with pH.  TOC also had a correlation with DOM., while colour correlated and depended strongly on Fe, within the bog ditches. Therefore, the bog ditch has behaved to contribute some amount of the brownification, found in Southern Swedish Lakes and Rivers. This knowledge might be useful in future, for more studies and control of Swedish fresh water brownification.

During the last three decades, a number of studies based on national environmental monitoring data have found increased concentrations of total organic carbon (TOC) in surface waters in much of the northern hemisphere including Sweden. There are many hypothesis of what has been the main cause of this trend, including changes in land use, decreased atmospheric deposition of acidifying compounds and climate change. Different hypothesis may have different implications for quantifying pre-industrial levels and for future predictions of TOC concentrations, which in turn will have different implications for water classification according to the European Water Framework Directive, water management and drinking water treatment. To analyse the long term effects of industrialisation and climate change on TOC in surface waters there is a need for long term time series of data. Since environmental monitoring data in Sweden only extends back to the mid-1980s, other techniques must be used in order to reconstruct data. In this study, sediment cores from 17 lakes along a climatic and deposition gradient in Sweden were collected and analysed with visible near infrared spectroscopy (VNIRS), an analytical technique that makes it possible to reconstruct historic surface water concentrations of TOC to pre-industrial conditions. A previous study with VNIRS showed that TOC concentrations declined in response to sulfate deposition until peak sulfur deposition in 1980, and thereafter increased as a result of sharp reductions of sulfate emissions. It was noted that the rate of increase of TOC after 1980 was faster than the rate of decrease due to sulfate deposition before 1980. The purpose of this study was therefore to explore the hypothesis that increasing TOC concentrations have not only been due to recovery from acidification, but also due to changes in climate. It was possible to analyse the long term effects of industrialisation and climate change on surface water TOC by analysing the reconstructed TOC data together with climate data from the beginning of the 1900s, modelled data of atmospheric sulfate deposition and environmental monitoring data, with uni- and multivariate analysis methods. It was found that the recent increase in TOC concentrations could be explained by both decreases in acidifying atmospheric deposition and increased precipitation, while temperature may have a decreasing effect on TOC. It was also found that the rate of increase of TOC-concentrations has been faster in the colder northern parts of Sweden and slower in the warmer south. The results imply that TOC concentrations will continue to rise to unpreceded levels and should be of concern for drinking water treatment plants that will need to adapt their treatment processes in the future. / Under de senaste tre årtiondena har ett flertal studier baserade på data från nationella miljöövervakningsprogram rapporterat ökande koncentrationer av organiskt kol (TOC) i ytvatten på norra halvklotet inklusive Sverige. Det finns många hypoteser om vad som ligger bakom trenden, till exempel förändringar i markanvändning, minskad atmosfärisk deposition av försurande ämnen och klimatförändringar. Olika förklaringar till vad som ligger bakom den ökande trenden ger konsekvenser vid kvantifiering av förindustriella nivåer och för förutsägelser om framtida koncentrationer, vilket i sin tur ger konsekvenser för vattenklassificering enligt Ramvattendirektivet, vattenförvaltning och dricksvattenberedning. För att kunna analysera de långsiktiga effekterna av industrialisering och klimatförändringar på TOC i ytvatten behövs långa tidsserier av data. Då den svenska miljöövervakningen endast sträcker sig tillbaka till mitten av 1980-talet måste andra tekniker användas för att rekonstruera data. I den här studien har sedimentproppar från 17 sjöar längs en klimat- och depositionsgradient analyserats med visible near infrared spektroskopi (VNIRS), en analysteknik som gör det möjligt att rekonstruera TOC-koncentrationer i ytvatten till förindustriell tid. En tidigare studie med VNIRS visade att TOC-koncentrationer sjönk till följd av försurande nedfall fram till 1980 då nedfallet kraftigt minskade, varefter koncentrationer av TOC började öka. Det noterades i studien att ökningen av TOC efter 1980 varit snabbare än vad minskningen var före 1980 på grund av försurande nedfall. Syftet med den här studien var därför att undersöka hypotesen att den senaste tidens ökning av TOC inte bara berott på minskat nedfall av försurande ämnen, utan även på grund av klimatförändringar. Det var möjligt att undersöka de långsiktiga effekterna av industrialisering och klimatförändringar på TOC i ytvatten genom att analysera rekonstruerad TOC data, klimatdata från början av 1900-talet, modellerad sulfatdepositionsdata och miljöövervakningsdata med uni- och multivariata analysmetoder. Resultaten visade att den senaste tidens ökning av TOC kunde förklaras med både en minskande deposition av försurande ämnen och en ökad nederbörd, medan ökande temperaturer kan ha haft en minskande effekt på TOC. Resultaten visade även att förändringshastigheten av TOC-koncentrationer varit snabbare i de norra, kalla delarna av Sverige och långsammare i de varmare södra. Resultaten indikerar att koncentrationer av TOC kommer att öka till nivåer som aldrig tidigare skådats, vilket är något vattenreningsverk kommer att behöva anpassa sina reningsmetoder till i framtiden.

A presente pesquisa está centrada na interpretação das análises de palinofácies e de geoquímica orgânica realizadas em três perfis sedimentares (T1, T2 e T3) de zonas úmidas continentais influenciadas por diferentes regimes hidrológicos na faixa climática subtropical durante o Quaternário no sul do Brasil (Estado do Rio Grande do Sul) com o principal objetivo de demonstrar a utilidade dessas análises para a obtenção de dados paleoclimáticos e paleoambientais. A análise de palinofácies realizada nos testemunhos T1-Mina do Museu (7.963 anos antes do presente - AP) e T2-Mina Modelo (9.542 anos AP), provenientes de Ametista do Sul, e no testemunho T3-Iraí (10.586 anos BP), proveniente de Iraí, revelou um amplo domínio do Grupo Fitoclasto. Os Palinomorfos são o segundo grupo dominante e o Grupo Produto Amorfo é o menos abundante. Esse tipo de análise foi particularmente eficaz para as interpretações dos eventos de precipitação e de sucessão vegetacional em Ametista do Sul, porque o isolamento hidrológico desses alagados efêmeros de altitude torna-os muito sensíveis aos efeitos climáticos. As flutuações na profundidade da água foram inferidas a partir das concentrações dos elementos autóctones (especialmente Botryoccocus e outras algas), que predominam nos intervalos basais e tendem a diminuir progressivamente em direção ao topo. Pseudoschizaea, por sua vez, parece atuar como um marcador biológico de intervalos de transição. O aumento da frequência e da variedade dos esporomorfos terrestres nas camadas mais superficiais indica um aumento da diversidade vegetal e está relacionado ao processo de evolução sucessional da área. Para Ametista do Sul, os resultados permitiram determinar que as oscilações nos padrões de umidade resultaram em um padrão intermitente do nível de água dos alagados, o qual pode representar um reflexo de mudanças climáticas regionais ou, talvez, de mudanças em escala global relacionadas com os “eventos Bond”. Em Iraí, a fração orgânica melhor representada é constituída por elementos derivados de plantas terrestres, uma característica típica da matéria orgânica preservada em turfeiras Esse tipo de ambiente úmido nunca chegou a secar completamente, uma vez que os teores de umidade eram subsidiados por diferentes fatores, tais como o nível do lençol freático, as inundações do Rio Uruguai e a água da chuva. A ocorrência muito baixa de algas, contudo, indica que a profundidade da água não era suficientemente espessa para o desenvolvimento da biomassa algálica, embora o ambiente anóxico e redutor também possa ter limitado a expansão deste grupo. Os parâmetros organogeoquímicos foram particularmente úteis para interpretações de eventos de anoxia e de mudanças nos regimes hidrológicos dos sedimentos turfosos. Os teores de carbono orgânico total (COT) e enxofre total (ST) são mais altos na porção basal do perfil, diminuindo em direção ao topo, e podem estar relacionados ao regime hidrológico ou à interferência antrópica na dinâmica da paisagem. O teor anômalo de enxofre observado em uma das amostras de Iraí pode ser devido a uma fonte externa e talvez relacionado com a presença de fontes termais na região. A presente pesquisa tem potencial como uma referência moderna capaz de ser aplicada na reconstrução de paleoambientes continentais análogos associados a regiões alagadas em cinturões subtropicais. / The present research focuses on the interpretation of the palynofacies and organic geochemistry analyses performed on three sedimentary cores (T1, T2 and T3) from continental wetlands influenced by different hydrological regimes in the sub-tropical climatic belt during the Quaternary in southern Brazil (Rio Grande do Sul State), with the main goal of demonstrating the usefulness of these analyses for obtaining paleoclimatic and palaeoenvironmental data. Palynofacies analysis was performed for the cores T1-Mina do Museu (7963 years before present - BP) and T2-Mina Modelo (9542 years BP) from Ametista do Sul, and for the T3-Iraí core (10586 years BP) from Iraí and revealed a high dominance of the Phytoclast Group. The Palynomorph is the second most dominant group and the Amorphous Product is the least abundant group. This kind of analysis was particularly effective in the interpretations of rainfall events and vegetation succession in Ametista do Sul, because the hydrological isolation renders the ephemeral ponds at high altitude highly sensitive to climatic effects. The fluctuations in the water depth are inferred from the concentration of the autochthonous elements (especially Botryoccocus and other algae), which predominate in the basal intervals and tend to decrease progressively towards the top. Pseudoschizaea, in its turn, appears to act as a biological marker for transitional intervals. The increasing frequency and variety of the terrestrial sporomorphs in the topmost interval indicate an increased vegetal diversity and is most likely related to the process of successional evolution of the area. For Ametista do Sul, the results allowed to determine that the oscillations in the moisture pattern resulted in the intermittent feature of pond water level and this may reflect the regional climate changes or perhaps the global scale changes related to the Bond events. In Iraí, the better represented organic fraction consists of elements derived from terrestrial plants, a characteristic typical of organic matter preserved in peat bogs. This kind of wetland never dried completely, since the moisture content was subsidized by different factors, such as the groundwater, the flood events of the Uruguay River and the rainfall water. The very low occurrence of algae, however, indicates that the water was not deep enough for the development of algalic biomass, although the anoxic, reducing environment may also have limited the expansion of this group. The organic geochemistry parameters were particularly useful for interpretation of anoxia events and changes of hydrological regimes in the peaty sediment. The total organic carbon (TOC) and the total sulfur (TS) contents are higher in the basal portion of the profile, decreasing towards the top and could be linked to hydrologic regimes or to anthropogenic interference in the landscape dynamics. The anomalous TS content observed in one of the samples from Iraí might be due to an external source and perhaps related to the presence of thermal springs in the region. The present research has potential as a modern reference that can be applied in the reconstruction of past analogous continental paleoenvironments associated to wetland areas in subtropical belts.

A presente pesquisa está centrada na interpretação das análises de palinofácies e de geoquímica orgânica realizadas em três perfis sedimentares (T1, T2 e T3) de zonas úmidas continentais influenciadas por diferentes regimes hidrológicos na faixa climática subtropical durante o Quaternário no sul do Brasil (Estado do Rio Grande do Sul) com o principal objetivo de demonstrar a utilidade dessas análises para a obtenção de dados paleoclimáticos e paleoambientais. A análise de palinofácies realizada nos testemunhos T1-Mina do Museu (7.963 anos antes do presente - AP) e T2-Mina Modelo (9.542 anos AP), provenientes de Ametista do Sul, e no testemunho T3-Iraí (10.586 anos BP), proveniente de Iraí, revelou um amplo domínio do Grupo Fitoclasto. Os Palinomorfos são o segundo grupo dominante e o Grupo Produto Amorfo é o menos abundante. Esse tipo de análise foi particularmente eficaz para as interpretações dos eventos de precipitação e de sucessão vegetacional em Ametista do Sul, porque o isolamento hidrológico desses alagados efêmeros de altitude torna-os muito sensíveis aos efeitos climáticos. As flutuações na profundidade da água foram inferidas a partir das concentrações dos elementos autóctones (especialmente Botryoccocus e outras algas), que predominam nos intervalos basais e tendem a diminuir progressivamente em direção ao topo. Pseudoschizaea, por sua vez, parece atuar como um marcador biológico de intervalos de transição. O aumento da frequência e da variedade dos esporomorfos terrestres nas camadas mais superficiais indica um aumento da diversidade vegetal e está relacionado ao processo de evolução sucessional da área. Para Ametista do Sul, os resultados permitiram determinar que as oscilações nos padrões de umidade resultaram em um padrão intermitente do nível de água dos alagados, o qual pode representar um reflexo de mudanças climáticas regionais ou, talvez, de mudanças em escala global relacionadas com os “eventos Bond”. Em Iraí, a fração orgânica melhor representada é constituída por elementos derivados de plantas terrestres, uma característica típica da matéria orgânica preservada em turfeiras Esse tipo de ambiente úmido nunca chegou a secar completamente, uma vez que os teores de umidade eram subsidiados por diferentes fatores, tais como o nível do lençol freático, as inundações do Rio Uruguai e a água da chuva. A ocorrência muito baixa de algas, contudo, indica que a profundidade da água não era suficientemente espessa para o desenvolvimento da biomassa algálica, embora o ambiente anóxico e redutor também possa ter limitado a expansão deste grupo. Os parâmetros organogeoquímicos foram particularmente úteis para interpretações de eventos de anoxia e de mudanças nos regimes hidrológicos dos sedimentos turfosos. Os teores de carbono orgânico total (COT) e enxofre total (ST) são mais altos na porção basal do perfil, diminuindo em direção ao topo, e podem estar relacionados ao regime hidrológico ou à interferência antrópica na dinâmica da paisagem. O teor anômalo de enxofre observado em uma das amostras de Iraí pode ser devido a uma fonte externa e talvez relacionado com a presença de fontes termais na região. A presente pesquisa tem potencial como uma referência moderna capaz de ser aplicada na reconstrução de paleoambientes continentais análogos associados a regiões alagadas em cinturões subtropicais. / The present research focuses on the interpretation of the palynofacies and organic geochemistry analyses performed on three sedimentary cores (T1, T2 and T3) from continental wetlands influenced by different hydrological regimes in the sub-tropical climatic belt during the Quaternary in southern Brazil (Rio Grande do Sul State), with the main goal of demonstrating the usefulness of these analyses for obtaining paleoclimatic and palaeoenvironmental data. Palynofacies analysis was performed for the cores T1-Mina do Museu (7963 years before present - BP) and T2-Mina Modelo (9542 years BP) from Ametista do Sul, and for the T3-Iraí core (10586 years BP) from Iraí and revealed a high dominance of the Phytoclast Group. The Palynomorph is the second most dominant group and the Amorphous Product is the least abundant group. This kind of analysis was particularly effective in the interpretations of rainfall events and vegetation succession in Ametista do Sul, because the hydrological isolation renders the ephemeral ponds at high altitude highly sensitive to climatic effects. The fluctuations in the water depth are inferred from the concentration of the autochthonous elements (especially Botryoccocus and other algae), which predominate in the basal intervals and tend to decrease progressively towards the top. Pseudoschizaea, in its turn, appears to act as a biological marker for transitional intervals. The increasing frequency and variety of the terrestrial sporomorphs in the topmost interval indicate an increased vegetal diversity and is most likely related to the process of successional evolution of the area. For Ametista do Sul, the results allowed to determine that the oscillations in the moisture pattern resulted in the intermittent feature of pond water level and this may reflect the regional climate changes or perhaps the global scale changes related to the Bond events. In Iraí, the better represented organic fraction consists of elements derived from terrestrial plants, a characteristic typical of organic matter preserved in peat bogs. This kind of wetland never dried completely, since the moisture content was subsidized by different factors, such as the groundwater, the flood events of the Uruguay River and the rainfall water. The very low occurrence of algae, however, indicates that the water was not deep enough for the development of algalic biomass, although the anoxic, reducing environment may also have limited the expansion of this group. The organic geochemistry parameters were particularly useful for interpretation of anoxia events and changes of hydrological regimes in the peaty sediment. The total organic carbon (TOC) and the total sulfur (TS) contents are higher in the basal portion of the profile, decreasing towards the top and could be linked to hydrologic regimes or to anthropogenic interference in the landscape dynamics. The anomalous TS content observed in one of the samples from Iraí might be due to an external source and perhaps related to the presence of thermal springs in the region. The present research has potential as a modern reference that can be applied in the reconstruction of past analogous continental paleoenvironments associated to wetland areas in subtropical belts.