Made available in DSpace on 2014-12-17T15:01:31Z (GMT). No. of bitstreams: 1 EnioRMS_DISSERT.pdf: 3992326 bytes, checksum: bb9137184687e3f768baf2f24b7cf158 (MD5) Previous issue date: 2013-08-08 / Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico / Studies show the great influence of free radicals and other oxidants as responsible for aging and degenerative diseases. On the other hand, the natural phenolic compounds has shown great as antioxidants to inhibit lipid peroxidation and lipoxygenase in vitro. Among these, is highlighted trans-resveratrol ( 3,5,4 `- trihydroxystilbene ) phenolic compound , characterized as a polyphenol stilbene class. The vegetables popularly known as "Azedinha" (Rumex Acetosa) has trans-resveratrol in its composition and from this, the present work aimed to study on the supercritical extraction and conventional extraction (Soxhlet and sequential) in roots of Rumex Acetosa, evaluating the efficiency of extractive processes, antioxidant activity, total phenolic content and quantification of trans-resveratrol contained in the extracts. Extractions using supercritical CO2 as solvent, addition of co-solvent (ethanol) and were conducted by the dynamic method in a fixed bed extractor. The trial met a 23 factorial design with three replications at the central point, with the variable reply process yield and concentration of trans-resveratrol and pressure as independent variables, temperature and concentration of co-solvent (% v/v). Yields ( mass of dry extract / mass of raw material used ) obtained from the supercritical extraction ranged from 0,8 to 7,63 % , and the best result was obtained at 250 bar and 90 ?C using the co-solvent 15% ethanol (% v/v). The value was calculated for YCER a flow rate of 1,0 ? 0,17 g/min resulting in 0,0469 CO2 ( g solute / g solvent ). The results of the mass yield varied between conventional extractions 0,78 % ( hexane) and 9,97 % (ethanol). The statistical model generated from the data of the concentration of trans-resveratrol performed as meaningful and predictive for a 95% confidence. GC analysis on HPLC (High Performance Liquid Chromatography), transresveratrol was quantified in all extracts and concentration values ranged between 0,0033 and 0,42 ( mg / g extract) for supercritical extracts and between 0,449 and 17,046 (mg / g extract) to conventional extractions and therefore, the Soxhlet extraction with ethanol for more selective trans-resveratrol than the supercritical fluid. Evaluation of antioxidant (radical method to sequester 2,2- diphenyl-1- picryl - hydrazyl - DPPH) the supercritical extracts resulted in EC50 values (concentration effective to neutralize 50% of free radicals) of between 7,89 and 18,43 mg/mL , while resulting in a Soxhlet extraction with EC50 values in the range of 6,05 and 7,39 mg/mL. As for quantification of the phenolic compounds (Method Spectrophotometer Folin-Ciocalteau) the supercritical extracts resulted in values between 85,3 and 194,79 mg GAE / g extract, whereas values derived from the Soxhlet extract resulted in values between 178,5 and 237,8 mg GAE / g extract. The high antioxidant activity can not be attributed solely to the presence of phenolic compounds, but the presence of other antioxidants in the existing Rumex acetosa / Estudos revelam a grande influ?ncia dos radicais livres e outros oxidantes como respons?veis pelo envelhecimento e por doen?as degenerativas. Por outro lado, os compostos fen?licos naturais tem-se apresentado como ?timos antioxidantes por inibirem a peroxida??o lip?dica e a lipooxigenase in vitro. Dentre estes, encontra-se em destaque o trans-resveratrol (3,5,4 trihidroxiestilbeno), composto fen?lico, caracterizado como um polifenol da classe estilbeno. A hortali?a popularmente conhecida como Azedinha (Rumex acetosa) possui o trans-resveratrol em sua composi??o e a partir disto, o presente trabalho teve como objetivo geral o estudo sobre a extra??o supercr?tica e a extra??o convencional (Soxhlet e sequencial) em ra?zes da Rumex acetosa, avaliando-se a efici?ncia dos processos extrativos, a atividade antioxidante, o teor de fen?licos totais e a quantifica??o do trans-resveratrol contido nos extratos. As extra??es supercr?ticas utilizaram CO2 como solvente, adicionado de co-solvente (etanol) e foram conduzidas pelo m?todo din?mico em um extrator de leito fixo. Os ensaios obedeceram a um planejamento fatorial 23 com triplicata no ponto central, tendo como vari?vel resposta o rendimento do processo e a concentra??o de trans-resveratrol e como vari?veis independentes a press?o, a temperatura e a concentra??o de co-solvente (% v/v). Os rendimentos (massa de extrato seco/ massa de mat?ria-prima utilizada) obtidos da extra??o supercr?tica variaram de 0,8 a 7,63%, sendo que o melhor resultado foi obtido a 250 bar e 90?C, com uso do co-solvente etanol a 15% (v/v). O valor de YCER foi calculado para uma vaz?o de 1,0 ? 0,17 g/min de CO2 resultando em 0,0469 (g soluto/ g solvente). Os resultados de rendimento em massa para as extra??es convencionais variaram entre 0,78% (hexano) e 9,97% (etanol). O modelo estat?stico gerado a partir dos dados de concentra??o de transresveratrol se apresentou como significativo e preditivo para uma confian?a de 95%. Atrav?s de an?lises cromatogr?ficas em CLAE (Cromatografia L?quida de Alta Efici?ncia), o transresveratrol foi quantificado em todos os extratos obtidos e os valores de concentra??o variaram entre 0,0033 e 0,42 (mg/g extrato) para os extratos supercr?ticos e entre 0,449 e 17,046 (mg/g extrato) para extra??es convencionais, sendo, portanto, a extra??o Soxhlet com etanol mais seletiva em trans-resveratrol que a supercr?tica. A avalia??o do poder antioxidante Extra??o, caracteriza??o e avalia??o bioativa do extrato de Rumex acetosa iii ?nio Rafael de Medeiros Santos, Agosto de 2013 (m?todo do sequestro do radical 2,2-difenil-1-picril-hidrazil-DPPH) dos extratos supercr?ticos resultaram em valores de EC50 (Concentra??o efetiva que neutraliza 50% dos radicais livres) compreendidos entre 7,89 e 18,43 μg/mL, enquanto que as extra??es com Soxhlet resultaram em valores de EC50 na faixa de 6,05 e 7,39 μg/mL. J? a quantifica??o dos compostos fen?licos totais (M?todo espectrofot?metro de Folin-Ciocalteau) dos extratos supercr?ticos resultaram em valores compreendidos entre 85,3 e 194,79 mg EAG/g extrato, enquanto que os valores dos extratos oriundos do Soxhlet resultaram em valores compreendidos entre 178,5 e 237,8 mg EAG/g extrato. A alta atividade antioxidante pode ser atribu?da n?o somente ? presen?a de compostos fen?licos, mas tamb?m ? presen?a de outros antioxidantes existentes na Rumex acetosa

Made available in DSpace on 2014-12-17T15:01:49Z (GMT). No. of bitstreams: 1 MagnaASBS_TESE.pdf: 3923978 bytes, checksum: 8e72f73f17946076f17005a65118a1ff (MD5) Previous issue date: 2010-02-23 / This work study of solar distillation feasibility in effluent of petroleum industry: produced water, making possible your reuse for irrigation of oleaginous cultures or fodder crops or in steam generation, as well the transport phenomena involved. The methodology for development of this project was to characterize the effluent to be treated and to accomplish physical and chemical analysis in the distilled, to build distillation equipment, concomitant operation of both equipments and implementation of data processing and economical evaluation. The methodology used for all parameters is outlined in APHA (1998) and sampling of the type compound. The feeding of distillation equipment was performed with treated effluent from UTPF of Guamar?. The temperature was monitored throughout the distillers and during the time of operation. The distillers feed occur, as a rule, for sifon. The distillers were operated by a period of 17 months between July 2007 and February 2009, in which 40 experiments were performed. The radiation and temperature datas were acquired in the INPE s site and the temperature inside of the distillers was registered by DATALOGGER Novus. The rates of condensation (mL / min) were determined by measuring of the flow in a graduate test tube of 10 mL and a chronometer. We used two simple solar effect distillers of passive type with different angles in coverage: 20 ? and 45 ?. The results obtained in this study and the relevant discussions are divided into six topics: sample characterization and quality of distilled; construction of distillers; operation (data, temperature profile), climatic aspects, treatment of data and economical analysis. Results obtained can be inferred that: the energy loss by the adoption of vessel glass was not significant, however, complicates the logistics of maintenance the equipment on a large scale. In the other hand, the surface of the tub with a glass shield on the equipment deterioration, both devices showed similar performance, so there is not justified for use of equipment 450. With regard to the climatological study it was verified that the Natal city presents monthly medium radiation varying in a range between 350 and 600 W/m2, and medium of wind speed of 5 m / s. The medium humidity is around 70% and rainfall is very small. The regime of the system is transient and although it has been treated as a stationary system shows that the model accurately represents the distillers system's 20 degrees. The quality of the distilled with regard to the parameters evaluated in this study is consistent with the Class 3 waters of CONAMA (Resolution 357). Therefore we can conclude that solar distillation has viability for treat oilfield produced water when considered the technical and environmental aspects, although it is not economically viable / Esse trabalho visa estudar a viabilidade da Destila??o Solar no polimento de efluentes oleosos: ?gua produzida, de forma a possibilitar o seu reuso na irriga??o de culturas oleaginosas ou forrageiras ou ainda na gera??o de vapor, bem como estudar os fen?menos de transporte envolvidos. A metodologia para desenvolvimento do projeto consistiu em caracterizar o efluente a ser tratado e realizar an?lises f?sico-qu?micas no destilado, construir os equipamentos de destila??o, opera??o concomitante dos dois destiladores e realiza??o de tratamento dos dados e avalia??o econ?mica. A metodologia utilizada para todos os par?metros ? a preconizada no APHA (1998) e a amostragem do tipo composta. A alimenta??o dos equipamentos de destila??o foi realizada com efluente tratado oriundo da UTPF de Guamar?. A temperatura foi monitorada ao longo dos destiladores e durante o tempo em que os mesmos estiveram em opera??o. A alimenta??o dos destiladores ocorria, via de regra, por sifonamento. Os destiladores foram operados por um per?odo 17 meses, entre julho de 2007 e fevereiro de 2009, nos quais foram realizados 40 experimentos. Os dados de radia??o e temperatura ambiente foram adquiridos atrav?s do site do INPE e as temperaturas dentro dos destiladores atrav?s de registradores do tipo DATALOGGER da Novus. As taxas de condensa??o (mL/min) foram determinadas atrav?s da medi??o do escoamento em proveta graduada de 10 mL e cron?metro. Foram utilizados dois destiladores solares simples efeito do tipo passivo com diferentes ?ngulos de inclina??o na cobertura: 20? e 45 ?. Os resultados obtidos nesse trabalho bem como as discuss?es pertinentes est?o subdivididos em seis t?picos: caracteriza??o da amostra e qualidade do destilado; constru??o dos destiladores; opera??o (dados obtidos, perfil de temperatura); aspectos clim?ticos; tratamento dos dados e an?lise econ?mica. Diante dos resultados obtidos pode se inferir que: a perda energ?tica pela ado??o da cuba de vidro n?o foi significativa, entretanto, dificulta a log?stica de manuten??o dos equipamentos em larga escala; por outro lado, o revestimento da cuba com vidro protegeria a base do equipamento da deteriora??o; os dois equipamentos demonstraram desempenho semelhante, logo n?o se justifica o uso do equipamento de 45 ?. Com respeito ao estudo climatol?gico verificou-se que a Cidade do Natal apresenta radia??es m?dias mensais variando entre 350 e 600 W/m2, aproximadamente e velocidade dos ventos m?dia de 5 m/s. Os teores de umidade m?dios ficam em torno dos 70 % e a pluviosidade ? bem pequena. O regime do sistema ? transiente e embora tenha sido dado tratamento de sistema estacion?rio verifica-se que o modelo representa adequadamente o sistema do destilador de 20?. A qualidade do destilado com respeito aos par?metros avaliados nesse estudo ? compat?vel com a Classe 3 de ?guas do CONAMA (Resolu??o 357). Logo se pode concluir que a destila??o solar tem viabilidade para polimento de ?guas produzidas quando considerados os aspectos t?cnicos e ambientais, embora n?o seja vi?vel economicamente

Made available in DSpace on 2014-12-17T15:12:11Z (GMT). No. of bitstreams: 1 LourivalBCJ_TESE_Parcial.pdf: 250865 bytes, checksum: f14aa43941c04261875d66a11af3e2e4 (MD5) Previous issue date: 2014-02-20 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior / 2020-01-01 / Este trabalho tem como objetivo geral mostrar que no F?don de Plat?o, a associa??o entre o argumento dos contr?rios e o argumento da reminisc?ncia (72e 77e) seguida da analogia da investiga??o do eclipse do sol (99d-102a), que serve de modelo ao m?todo de investiga??o ideal mostra que o m?todo naturalista de investiga??o direta dos fen?menos (99c-100b) n?o conduz, necessariamente, ao verdadeiro conhecimento. Como m?todo, adotou-se uma leitura comparativa e uma interpreta??o por aproxima??o do texto fonte. O resultado aqui obtido ? a no??o de como se d? o conhecimento no referido di?logo. Como conclus?o se afirma que, nessa obra o conhecimento ? uma esp?cie de recorda??o que se d? como reciprocidade entre um processo negativo de cogni??o e o estado cognitivo inato

This study concerns in a three peatland sites: the epilitorals of Pilská reservoir and Hořejší Padrťský fishpond in Příbram region and Kamenný fishpond in Pilsen. These peat-bobg were affected by negative conseqences of human activities. The aim of this study is to find out what kind these changes was and what extent they were. The changes in vegetation were observed from two points of view. The GIS analyses of aerial photographs represent the macroscale view. Repeating of old phytosociological relevées was the microscale view. To understand the cause of vegetation changes, the species-environment analyses were used. Four transects were made for this purpose and a water table level, pH and conductivity were mesured monthly along these transects. One-shot measurements of N and P water concentration and a peat depth were also carried out. Measured data from transects were uses in multivariate vegetation analyses and also in one- way analysis, aimed to an expansion plant species. All three sites of concern came through strong changes in past. In all of them the area of biotops of great conservation importance decreased and some endangered plant species have been lost there. The changes in Pilská reservoir epilitoral were mostly anthropogenic, whereas the mires of Hořejší Padrťský fishpond and Kamenný...

The middle Holocene cataclysmic eruption of Mount Mazama blanketed Walker Rim, in south central Oregon, with 270 cm to 300 cm of pumice, causing capture of surface water systems by groundwater, stream relocation, and the formation of biologically diverse fens and seasonal wetlands. The pumice aquifer at Round Meadow, an 8.6 km2 basin, hosts both a fen and seasonally ponded wetlands. The Round Meadow watershed lies within a closed basin between the upper Klamath and Deschutes river basins. As the highest meadow at Walker Rim, it is a relatively well-constrained system to study the effects of hydrological disruption. A water budget was calculated for the basin, hydraulic conductivity was evaluated for the three main sediment layers in the meadow, recharge sources and evaporative trends were studied using stable isotope analysis, and aquifer residence times were estimated using CFC tracer water age dating. Water year 2014 was a drought year and observation of the system under stressed conditions allowed discrimination of four independently functioning components of the hydrogeologic system. These were the meadow, which is by far the largest component in terms of water storage, the fen where iron cementation and up to 1 m of peat holds water in a berm above the meadow, three springs which are sourced from deeper groundwater hosted in the bedrock which underlies the pumice deposit, and the outflow area. In all cases, the aquifer material is pumice, but the influence of the pre-eruption landscape and post-eruption modifications of the aquifer material have resulted in partial isolation of the components. The water budget analysis indicated that the basin lost 44 cm of water storage during WY 2014. Hydraulic conductivity values of 1x10-6, 2x10-2, and 4x10-5 cm/s, were determined for the diatomaceous silt underlying the pumice, the Plinian pumice fall aquifer, and for the diatomaceous silt overlying the pumice, respectively. The pumice is characterized as a perched, weakly confined aquifer and residence times in the pumice are much longer (decades) than for water near the surface of the meadow. Water discharging at the springs is isotopically different (lighter) than either the surface water or groundwater in the pumice aquifer. The fen at Round Meadow appears dependent on seasonal precipitation to recharge water, and responds to fluctuations in annual precipitation. The wetland meadows are volumetrically the main water-storing features at Round Meadow, and these are not homogenous features, but a combination of discrete components.

No description available.

Indiana University-Purdue University Indianapolis (IUPUI) / ABSTRACT Dustin Graves ASSESSING THE ROLE OF GEOLOGIC SETTING ON THE HYDROLOGY AND GROUND WATER GEOCHEMISTRY OF FENS IN THE GLACIATED MIDWESTERN UNITED STATES A water quality investigation of several fens located in the temperate glaciated Midwestern United States, near the southern limit of fen occurrence, was conducted to assess the role of geologic setting on the hydrogeochemical signature of fens and to compare hydrogeochemistry of fens located in different geographic and geologic settings. The five studied fens, located in the Central Till Plain physiographic region of Indiana, receive ground water sourced from glacial tills with very similar petrologic composition. These wetlands are hydrogeomorphically classified as slope wetlands with dominant ground water input. More specifically, these sites are inter-till / intra-till type fens (Type Ia and Ib) or outwash terrace type fens (Type II). Shallow ground water was collected just prior to surface interception (source water), and again after discharging into each fen (fen water) and measured for a suite of cations (Ca2+, Mg2+, K+, Na+) and anions (HCO3- SO42-, NO3-, NO2-, PO43-, and Cl-). Fen water hydroperiods showed similar dynamics, despite some variation in the hydrologic input of these systems (source water). Central Indiana fens are recognized as Ca2+, Mg2+, and HCO3- dominated systems. Fen water showed substantial evolution from source water at each study site, evidently the result of carbonate and gypsum dissolution dynamics. However, when only fen water is analyzed, results suggest that ground water of the southern fens represents geochemical similarity, with the exception of anthropogenic influence. The greatest geochemical variation among central Indiana fens can be attributed to Na+ and Cl-, which has been linked to road salt contamination at two of the study sites. This hydrogeochemical study also reveals that fens (slope wetlands) within this particular geologic setting of central Indiana show strong geochemical similarities to fens located throughout the temperate Northern Hemisphere. However, statistical analyses provide evidence that the parameters of Ca2+, HCO3-, and SO42- account for the greatest variation among these wetland communities, suggesting that calcium carbonate and gypsum dissolution dynamics are primarily fen specific while other parameters remain relatively homogenous across a wide geographical range. Lenore P. Tedesco, Ph. D.

Substanzen, die durch ihr hormonell wirksames Potenzial mit dem Hormonsystem interagieren und adverse Effekte auf die Reproduktion von Invertebraten und Vertebraten ausueben koennen, erlangten in den letzten Jahrzehnten große Aufmerksamkeit. Viele dieser Substanzen reduzieren die Fertilitaet oder die Fekunditaet, fuehren zu Abnormalitaeten in der Ontogenese oder im Verhalten der Tiere und haben Einfluss auf die Geschlechterverhaeltnisse. In der vorliegenden Arbeit wurden verschiedene Aspekte dieses Themengebietes bearbeitet. Das in Europa endemisch vorkommende Rotauge (Rutilus rutilus), ein Sueßwasserfisch, wurde als Modelltier fuer den Nachweis von (anti)androgenen Effekten auf aquatisch lebende Organismen etabliert. Zum Nachweis der (anti)androgenen Wirkmechanismen wurden die Tiere mit Modellsubstanzen aus drei verschiedenen Gruppen exponiert. Aus der Gruppe der Substanzen mit potenziell androgener Wirkung wurden Triphenylzinn (TPT) und Methyltestosteron (MT) verwendet, aus der Gruppe der Antiandrogene Vinclozolin (VIN) und Cyproteronazetat (CYP) und aus der Gruppe der Aromatasehemmer, und somit potenziell androgener Wirkung, Letrozol (LET) und Fenarimol (FEN). Feedbackmechanismen auf die Hypothalamus-Hypophysen-Gonaden-Achse (mRNA-Expression des Luteinisierenden Hormons, des Follikel stimulierenden Hormons und der Aromatase), mRNA-Expression potentieller Biomarker in der Leber (Androgen-Rezeptor-mRNA, Oestrogen-Rezeptor-mRNA), Sexsteroidspiegel im Blutplasma (17beta-Oestradiol und 11-keto-Testosteron), Enzymaktivitaeten im Gehirn (Aromatase), Histologie der Gonaden, Totallaenge, Gewicht und Geschlechterverteilung wurden als Endpunkte analysiert, um adverse Effekte auf die Reproduktionsbiologie von R. rutilus zu zeigen. Die untersuchten Endpunkte eigneten sich sehr gut zum Nachweis verschiedener Wirkmechanismen. / Substances that are able to interact with the endocrine system and cause adverse effects on the reproduction of invertebrates and vertebrates have gained much attention over the last few decades. Many of these substances reduce fertility or fecundity, lead to developmental abnormalities or abnormalities in the behaviour of animals and have an impact on sex ratios. The present study examines various aspects of these topics. The roach (Rutilus rutilus), a freshwater fish endemic in Europe, was established as a model animal for the detection of (anti)androgenic effects on aquatic organisms. For examination of the (anti)androgenic action, the animals were exposed to model compounds from three different groups: triphenyltin (TPT) and methyltestosterone (MT) from the group of substances with potentially androgenic effect, vinclozolin (VIN) and cyproteronacetate (CYP) from the group of antiandrogens, and letrozol (LET) and fenarimol (FEN) from the group of aromatase inhibitors, which thus have a potentially androgenic effect. Feedback mechanisms on the hypothalamus-pituitary-gonad-axis (mRNA expression of luteinising hormone, follicle stimulating hormone and aromatase), mRNA expression of potential biomarkers in the liver (androgen receptor mRNA, oestrogen receptor mRNA), steroid levels in the blood plasma (17beta-oestradiol and 11-ketotestosterone), enzyme activity in the brain (aromatase), histology of the gonads, total length, weight and sex ratios were analysed as endpoints to show adverse effects on the reproductive biology of R. rutilus. The studied endpoints are suitable for the detection of different modes of action. The histological examination of the gonads proved to be especially sensitive with the exposure to AACs to resulting in fundamental adverse damages to the gonads. It was ascertained that - in the early stages of ontogeny - androgens play as crucial of a role in the development of the gonads as previously attributed primarily to oestrogens.

Les tourbières couvrent 3 % des surfaces continentales et jouent un rôle important dans le cycle du carbone en stockant le tiers du carbone des sols. L'accumulation de tourbe est liée au déséquilibre production primaire/décomposition du à une activité microbienne limitée par les conditions environnementales. L'infection et la lyse virale ont un impact sur la diversité et l'activité des communautés microbiennes, et influent sur le cycle du carbone. Cependant, le fonctionnement de ce compartiment viral n'avait jamais été pris en compte dans les études de fonctionnement des tourbières. Le but de ce travail de thèse était d'analyser et comprendre la dynamique spatiale et temporelle de l'abondance et de la diversité virale des tourbières à Sphagnum. L'analyse de l'abondance virale et procaryote et de 12 metaviromes en lien avec la physico-chimie d'une tourbière tempérée en France montre une forte variation saisonnière des communautés virales. Cette variation semble très liée aux conditions environnementales générées par la fluctuation de la nappe d'eau. Dans cette même tourbière, l'analyse de la diversité taxonomique et fonctionnelle des communautés de microorganismes présents (métagénomes) et métaboliquement actifs (métatranscriptomes) indique que la structure taxonomique est différente entre les des deux principaux stades, le fen et le bog, mais que ces communautés présentent une diversité fonctionnelle similaire, dont l'expression est liée aux changements des conditions environnementales avec la profondeur. L'abondance des particules virales étudiées dans 5 tourbières à Sphagnum réparties en Finlande, au Canada, en France, et sur l'île subantarctique d'Amsterdam varie fortement avec les sites. L'analyse de la diversité virale de la matrice et de l'eau de tourbe du Canada et de Finlande montre que la diversité virale est structurée par le site, puis le stade dynamique, puis la profondeur, avec un rôle important de la saturation en eau au niveau du site. Ces résultats valident le fonctionnement proposé du compartiment viral et de la communauté d'hôtes procaryotes. Ces connaissances ont été utilisées pour analyser le fonctionnement du compartiment microbien de tourbières à Sphagnum soumises à des perturbations d'origine anthropique. Les 31 métaviromes produits pour cette thèse constituent l'une des plus grandes bases de données sur la diversité virale des écosystèmes alors que la diversité virale des sols n'avait presque jamais été étudiée auparavant. / Peatlands cover 3 % of the continental surfaces but represent up to a third of the soil carbon stock. Peat accumulation results from the imbalance between primary production and decomposition due to the limitation of the prokaryote activity caused by the environmental conditions. Viral infection and lysis impact the diversity and the activity of the microbial communities and influence the carbon cycle. However, the functioning of the viral compartment had never been taken into account in peatlands. The aim of this thesis was to gain knowledge about the spatio-temporal dynamic of viral abundance and diversity in Sphagnum-dominated peatlands. Spatio-temporal analysis of viral and prokaryote abundance and of 12 metaviromes (viral diversity) in relation to the physico-chemical features in a temperate Sphagnum-dominated peatland in France revealed the high seasonal variability of the viral communities. This dynamic appeared mainly related to the environmental conditions shaped by the fluctuation of the water-table level. In the same peatland the taxonomic diversity of the present microorganisms (metagenomes) differed between the fen and the bog, but these communities present a similar functional diversity, which expression in selected in the same way in the two dynamic stages, in relation to depth-related environmental conditions. Viral abundance analyzed in 5 Sphagnum-dominated peatlands from Finland, Canada, France and subantarctic Amsterdam Isle presented a high geographical variability. Investigation of the diversity of the viral communities from the peat matrix and the pore-water in Finland and Canada emphasized the structuration of the viral communities by the site, then the dynamic stage, and finally depth. These results confirm the first hypotheses about the functioning of the viral compartment depending on environmental conditions and prokaryote activity. Effects of human-derived disturbances on viral ecology in peatlands were investigated based on this knowledge. While soil viral diversity was poorly documented at the start of this thesis, the collection of 31 metaviromes from Sphagnum-dominated peatlands produced for this project represents the second largest dataset representing the viral diversity from environmental samples.

Niedermoore sind durch Grundwasser beeinflusste Standorte, in denen Torf gebildet wird oder oberflächig ansteht. Sie emittieren durch mikrobiologische Prozesse Treibhausgase (THG). Wird der Grundwasserstand gesenkt, steigen Kohlendioxid und Lachgas Emissionen, während bei einer Anhebung vermehrt Methan emittiert wird. Weltweit wird davon ausgegangen, dass Moore 5 % der anthropogen verursachten Emissionen verursachen. Um THG-Emissionen entgegenzuwirken, wird die Anhebung des Grundwasserstandes diskutiert. Dies führt durch eingeschränkte Befahrbarkeit und geringeres Kulturartenspektrum zu einer kaum gegebenen Wirtschaftlichkeit. Es fehlt ein Vergleich der THG-Emissionen und der Rentabilität der Bewirtschaftungssysteme verschiedener Landnutzungssysteme für Niedermoorstandorte der gemäßigten Klimazone. Die bodenbürtigen THG-Emissionen wurden mit einer Metaanalyse zu Veröffentlichungen von THG-Messungen in Niedermooren der gemäßigten Klimazone ermittelt. Ebenfalls wurden die bewirtschaftungsabhängigen Emissionen ermittelt und zu Gesamtemissionen zusammengefasst. Für den Vergleich der Rentabilität der Bewirtschaftungssysteme wurden Kosten und Erlöse berechnet. Abschließend wurden Treibhausgasvermeidungskosten abgeschätzt Bei zunehmender Landnutzungsintensität und größeren Grundwasserflurabstand nahmen die Gesamt-THG-Emissionen zu. Durch die Bewirtschaftung verursachte Emissionen spielten im Vergleich zu den bodenbürtigen Emissionen kaum eine Rolle. Zur THG-Einsparung und der Torferhaltung sollte die Bewirtschaftung extensiviert werden. Im Rentabilitätsvergleich erwiesen sich intensive, im Vergleich zu extensive Bewirtschaftungssysteme ohne Förderung als wirtschaftlich. Subventionen und Förderungen um torf- und klimaschonende Praktiken zu unterstützen, sind unverzichtbar. Mit dieser Arbeit wurde erstmalig für Niedermoore ein systematischer Überblick über die Gesamt-THG-Emissionen und die Rentabilität gängiger Bewirtschaftungssysteme verschiedener Landnutzungssysteme gegeben. / Fens are sites influenced by the groundwater where peat is formed in or located in the upper soil layer. They emit greenhouse gases (GHG) through microbiological processes in which the main influencing factor is the groundwater level. The lowering of the groundwater level increases carbon dioxide and dinitrogen monoxide emissions, while higher groundwater levels lead to methane emissions. It is assumed that fens cause 5% of global anthropogenic GHG emissions. In order to save peat and reduce GHG emissions, rewetting fens has been discussed and applied. This leads to low profitable land use due to limited trafficability and cultivation options. There is a lack of comparison of management systems in different land use systems regarding GHG emissions and profitability on fenlands in the temperate climate zone. The soil-borne GHG emissions for the land use systems were identified with a meta-analysis of published measurements of GHG emissions on fenlands in the temperate climate zone. The GHG emissions due to cultivation and possible land use changes were identified and summarized as the overall emissions. Costs and revenues were calculated for comparability purposes of profitability of management systems. GHG abatement costs were estimated too. Results indicated that overall GHG emissions increase with higher land use intensity and deeper groundwater level. Management induced GHG emissions are negligible compared to the soil-borne emissions. Fenlands should be extensified to save peats and reduce GHG emissions. The comparison of profitability showed that management systems of intensive land use systems, in contrast to extensive land use systems, with the low groundwater level are broadly profitable without subsidies. Subsidies and grants are indispensable to promote peat-saving and climate-friendly practices. This thesis provides a systematic overview of overall GHG emissions and profitability of common management systems of fenlands.