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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.
41

Liberation of low molecular weight organic acids from sedimentary organic matter and their role on microbial activity

Sauer, Patrick January 2013 (has links)
Low molecular weight organic acids (LMWOAs) are important nutrients for microbes. However, most LMWOAs do not exist freely in the environment but are bound to macromolecular organic matter, e.g. kerogen, lignite and coal. During burial and geological maturation of sedimentary macromolecular organic matter biological and abiological processes promote the liberation of LMWOAs into the surrounding sediment. Through this process, microbes in sedimentary subsurface environments are supplied with essential nutrients. To estimate the feedstock potential of buried macromolecular organic matter to many environments it is important to determine the amount of LMWOAs that are bound to such a matrix. However, high-pressure and high temperature are a key feature of deep subsurface environments, and these physical parameters have a profound influence on chemical reaction kinetics. Therefore it is essential for the estimation of the feedstock potential to generate high-pressure and high temperature for the liberation of LMWOAs to recreate true in-situ conditions. This work presents a newly developed, inexpensive incubation system for biological and geological samples. It allows the application of high-pressure and high temperature as well as a subsampling of the liquid phase without loss of pressure, thereby not disturbing the on-going processes. When simulating the liberation of LMWOAs from sedimentary organic matter, the newly developed incubation system produces more realistic results than other extraction systems like Soxhlet. The extraction products remain in the extraction medium throughout the extraction, influencing the chemical conditions of the extraction medium. Sub-bituminous coal samples from New Zealand as well as lignite samples from Germany were extracted at elevated temperature (90˚C) and pressure (5 MPa). The main LMWOAs released from these low rank coals were formate, acetate and oxalate. Extraction efficiency was increased by two to four times for formate, acetate and oxalate in comparison to existing extraction methods without pressurisation and with demineralised water. This shows the importance of pressure for the simulation of true in-situ conditions and suggests that the amount of bioavailable LMWOAs is higher than previously thought. With the increase in carbon capture and storage (CCS) and the enhanced recovery of oil and gas (EOR/EGR), more and more CO2 becomes injected into the underground. However, the effects of elevated concentrations of carbon dioxide on sedimentary organic matter are rarely investigated. As the incuabtion system allows the manipulation of the composition and partial pressure of dissolved gasses, the effect of highly gas-enriched (CO2, CO2/SO2, CO2/NO2; to simulate flue gas conditions) waters on the extraction yield of LMWOAs from macromolecular organic matter was evaluated. For sub-bituminous coal the concentrations of all LMWAOs decreased upon the addition of gas, irrespective of its composition, whereas for lignite formate always and acetate mostly increased, while oxalate decreased. This suggests an positive effect on the nutrient supply for the subsurface microbiota of lignite layers, as formate and acetate are the most common LMWOAs used for microbial metabolism. In terrestrial mud volcanoes (TMVs), sedimentary material is rapidly ascending from great depth to the surface. Therefore LMWOAs that were produced from buried macromolecular organic matter at depth are also brought up to the surface, and fuel heterotrophic microbial ecosystems at the surface. TMVs represent geochemically and microbiologically diverse habitats, which are supplied with organic substrates and electron acceptors from deep-seated hydrocarbon-generating systems and intersected shallow aquifers, respectively. The main electron donor in TMVs in Azerbaijan is sulphate, and microbial sulphate reduction leads to the production of a wide range of reduced sulphur species that are key players in several biological processes. In our study we estimated the effect of LMWOAs on the sulphur metabolising activity of microorganims in TMVs from Azerbaijan. The addition of a mixture of volatile fatty acids containing acetate and other LMWOAs showed significant positive response to the sulphate reduction rate (SRR) of samples of several mud volcanoes. Further investigations on the temperature dependency of the SRR and the characterisation of thermophilic sulphate-reducing bacteria (SRB) showed a connection between the deep hot subsurface and the surface. / Niedermolekulare organische Säuren (nachfolgend als LMWOAs - low molecular weight organic acids - bezeichnet) stellen wichtige mikrobielle Substrate dar. Jedoch liegen die meisten LMWOAs nicht in freier, bioverfügbarer Form vor, sondern sind vielmehr an hochmolekulare organische Substanzen gebunden, z.B. Kerogen, Lignit und Kohle. Während der geologischen Verbringung in tiefe Erdschichten und der geologischen Reifung von sedimentären hochmolekularen organischen Substanzen, führen biologische und abiologische Prozesse zu einer Freisetzung von LMWOAs in die umgebenden Sedimente. Durch diesen Prozess werden Mikroorganismen in unterirdischen sedimentären Ökosystemen mit essentiellen Nährstoffen versorgt. Um das Nährstoffpotential tief liegender hochmolekularer organischer Substanzen für diverse Ökosystemen abschätzen zu können, ist es notwendig, die Menge an LMWOAs, die an solch eine hochmolekulare Matrix gebunden ist, zu bestimmen. Dabei stellen hoher Druck sowie hohe Temperatur entscheidende Faktoren in tiefen unterirdischen Ökosystemen dar, welche einen signifikanten Einfluss auf chemische Reaktionen haben. Daher ist es für die Abschätzung des Nährstoffpotentials entscheidend, hohen Druck und hohe Temperatur bei der Freisetzung von LMWOAs zu erzeugen, um wahre in situ Bedingungen zu schaffen. In der vorliegenden Arbeit wird ein neu entwickeltes, preiswertes Inkubationssystem für biologische und geologische Proben präsentiert. Es erlaubt die Verwendung von hohem Druck als auch hoher Temperatur sowie eine Unterprobennahme der flüssigen Phase ohne Druckverlust, um den fortlaufende Prozess nicht zu unterbrechen. Bei der Simulierung der Freisetzung von LMWOAs aus sedimentären organischen Substanzen erhält man mit dem neu entwickelten Inkubationssystem realistischere Resultate als mit anderen Extraktionssystemen, wie z.B. eine Soxhlet-Apparatur. Die Extraktionsprodukte verbleiben während der Extraktion im Extraktionsmedium, wodurch die chemischen Bedingungen verändert werden. Kohleproben aus Neuseeland sowie aus Deutschland wurden mittels erhöhter Temperatur (90°C) und Druck (5 MPa) extrahiert. Die wichtigsten LMWOAs, die aus diesen Kohlen freigesetzt wurden, waren Formiat, Acetat und Oxalat. Die Extraktionseffizienz für diese LMWOAs konnte im Vergleich zu existierenden Extraktionsmethoden ohne Druck um den Faktor 2 bis 4 gesteigert werden. Dies zeigt die Bedeutung von Druck bei der Simulation von in situ Bedingungen und legt nahe, dass die Menge an bioverfügbaren LMWOAs größer ist als bisher angenommen. Durch die Zunahme der CO2-Speicherung im Untergrund (carbon capture and storage, CCS) sowie der erweiterten Förderung von Öl und Gas (enhanced recovery of oil and gas, EOR/EGR) wird immer mehr CO2 in den Untergrund gepresst. Jedoch sind die Auswirkungen von erhöhten CO2-Konzentrationen auf sedimentäre organische Materie noch unerforscht. Da mit dem Inkubationssystem die Veränderung der Zusammensetzung und des Partialdruckes von gelösten Gasen möglich ist, wurde der Effekt von hoch mit Gasen (CO2, CO2/SO2, CO2/NO2; um Kraftwerksabgase zu simulieren) angereicherten Wässern auf die Extraktionsausbeute von LMWOAs untersucht. Bei der subbituminösen Kohle zeigte sich eine Abnahme aller LMWOAs-Konzentrationen durch die Lösung von Gas im Extraktionsmedium, wobei die Art des Gases keine Rolle spielte. Bei Lignit konnte hingegen festgestellt werden, dass die Extraktionsausbeute an Formiat immer und an Acetat meistens erhöht wurde, während sie sich bei Oxalat verringerte. Dies deutet auf einen positiven Effekt für die Nährstoffversorgung von Mikroorganismen um Lignit-Lagerstätten an, da Formiat und Acetat die am häufigsten verwendeten LMWOAs im mikrobiellen Stoffwechsel darstellen. In terrestrischen Schlammvulkanen (terrestrial mud volcanoes, TMVs) steigt sedimentäres Material aus großen Tiefen an die Erdoberfläche. Somit werden auch LMWOAs, welche aus hochmolekularen organischen Substanzen freigesetzt werden, an die Oberfläche verbracht, und ermöglichen dort heterotrophe Ökosysteme. TMVs stellen dabei geochemisch und mikrobiell unterschiedliche Habitate dar, welche mit organischen Substraten und Elektronenakzeptoren aus tief liegenden, Kohlenwasserstoffe erzeugenden Systemen versorgt werden. In TMVs in Aserbaidschan stellt Sulfat den Hauptelektronenakzeptor dar, wobei mikrobielle Sulfatreduktion zu einer Vielzahl an reduzierten Schwefelspezies führt. In der vorliegenden Arbeit wurde der Effekt von LMWOAs auf die Aktivität von Mikroorganismen bei der Umsetzung von Schwefel in TMVs in Aserbaidschan untersucht. Die Zugabe einer Mischung verschiedener kurzkettiger Fettsäuren zu Schlammproben verschiedener TMVs erzeugte eine signifikant positive Reaktion in Bezug auf die Sulfat-Reduktionsraten. Weiterführende Untersuchungen zur Temperaturabhängigkeit der Sulfat-Reduktionsraten und die Charakterisierung thermophiler, Sulfat-Reduzierender Bakterien zeigte eine Verbindung zwischen der tiefen, heißen Biosphäre und der Erdoberfläche auf.
42

Alterações microbianas do solo sob sistema de semeadura direta e rotação de culturas

Borges, Clovis Daniel [UNESP] 24 February 2010 (has links) (PDF)
Made available in DSpace on 2014-06-11T19:27:23Z (GMT). No. of bitstreams: 0 Previous issue date: 2010-02-24Bitstream added on 2014-06-13T20:56:23Z : No. of bitstreams: 1 borges_cd_me_jabo.pdf: 505108 bytes, checksum: 33787dd8b93a99178ecd21571bb71189 (MD5) / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / A rotação de culturas é um processo de cultivo que pode modernizar e aumentar o rendimento da atividade agropecuária de forma sustentável agregando maior qualidade ao solo. Os objetivos deste estudo foram: (I) avaliar o efeito dos sistemas culturais em plantio direto conduzidos em rotação de culturas e monitorar as alterações das propriedades microbiológicas bioindicadoras da qualidade do solo; (II) investigar as mudanças bioquímicas nos solos decorrentes da adição de diferentes tamanhos de resíduos de soja e milho durante o período de incubação. Foram determinados as biomassas microbianas- C, N e P (CBM, NBM e PBM, respectivamente), a atividade respiratória (C-CO2) e das enzimas desidrogenase, fosfatase e urease, conteúdo do carbono orgânico (Corg), carbono solúvel (Csol), fósforo orgânico (Porg), matéria orgânica (MO), potencial de mineralização do N. O quociente metabólico (qCO2) e microbiano (qMIC) do solo foram calculados. Experimento (I): A avaliação foi realizada em amostras de solo coletadas após a colheita das culturas de verão do ano agrícola 2007/2008, na camada de 0-0,15 m de profundidade em um experimento conduzido sob sistema de semeadura direta, por seis anos. O delineamento experimental foi em blocos casualizados com esquema de faixas com três repetições. As sequências utilizadas foram as monoculturas de soja (Glycine max L.) (SS) e de milho (Zea mays L.) (MM) e a rotação de culturas soja/milho (SM). As culturas de inverno foram milho, girassol (Helianthus anuus L.), nabo forrageiro (Raphanus sativus L.), milheto (Pennisetum americanum (L.) Leeke), guandu (Cajanus cajan (L.) Millsp), sorgo (Sorghum bicolor (L.) Moench) e crotalária (Crotalária juncea L.). O conteúdo da biomassa microbiana-C, N e P do solo aumentou significativamente... / Crop rotation is a practice of growing dissimilar plants that can modernize and increase the farm economy in a sustainable form for adding more quality to the soil. The aims of this study were: (I) evaluate the effect of crop sequences under no-tillage systems on changes in the soil microbiological properties; (II) investigate the biochemistries changes during the incubation of the soil added with different sizes particles of soybean and corn. There were determined the contents of microbial biomass-C, N and P, the production of C-CO2, the activities of the enzymes dehydrogenase, urease and phosphatase, the organic carbon (Corg), soluble carbon (Csol), organic phosphorous (Porg) and organic matter (MO) contents and the potential of mineralization N. The soil metabolic (qCO2) and microbial (qMIC) quotients were calculated. Experiment (I): The evaluation was performed in soil samples collected after the summer crops harvest, on 2007/2008 growing season, at 0-0.15 m soil depth layer on an experiment conducted under no-tillage system through six years. The experimental had a completely randomized block design, in strips plots with three replications. The crop sequences were continuous soybean (Glycine max L.) (SS), continuous corn (Zea mays L.) (MM), and crop rotation soybean/corn (SM). Winter crops were corn, sunflower (Helianthus anuus L.), radish (Raphanus sativus L.), pearl millet (Pennisetum americanum (L.) Leeke), pigeon pea (Cajanus cajan (L.) Millsp), grain sorghum (Sorghum bicolor (L.) Moench) and sunn hemp (Crotalária juncea L.). The content of microbial biomass-C, N and P in the soil increased significantly in crop sequence SM compared to continuous crop. The interactions SM-millet and MMsorghum influenced the content of biomass-C, SM-hemp and SM-millet in the biomass-N content... (Summary complete electronic access click below)
43

Interferência de herbicidas nas características fisiológicas da mandioca e na atividade microbiana do solo / Interference of herbicides in physiological characteristics of cassava and soil microbial activity

Silveira, Hellen Martins da 16 July 2012 (has links)
Made available in DSpace on 2015-03-26T13:40:02Z (GMT). No. of bitstreams: 1 texto completo.pdf: 887684 bytes, checksum: 41ebea32ab60b420dfe0a4aa8605373a (MD5) Previous issue date: 2012-07-16 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / In this study evaluated the effects of herbicides mesotrione, fluazifop-p-butyl, fomesafen and fluazifop-p-butyl + fomesafen on physiological characteristics of cassava cultivars, and also the action of mesotrione and fluazifop-p-butyl on microbial activity of rhizosphere of the cultivars. Thus, in four experiments were evaluated: physiological characteristics of cassava cultivars after application of mesotrione; interference of fluazifop-p-butyl and fomesafen in separate and mixture application on water use efficiency and photosynthetic characteristics of cassava cultivars; and the action of mestrione and fluazifop-p-butyl on the microbial activity in the rhizosphere of the Cacau-UFV cultivar at 30 and 60 days after herbicide application. The Platina cultivar was more tolerant to mesotrione and Coqueiro cultivar showed less water use efficiency after applications. The transpiration rate, stomatal conductance and water use efficiency of cassava plants increased according to doses of fomesafen + fluazifop-p-butyl. These effects were not observed when the herbicides were applied separately. The cassava cultivars presented differential tolerance to herbicides fomesafen and fluazifop-p-butyl, and fluazifop-p-butyl was more selective to culture. There was an increase in mycorrhizal colonization of Cacau-UFV roots at 30 days for both herbicides and 60 days only for fluazifop-p- butyl, however, these products did not interfere on qCO2. The cassava crop was more tolerant to mesotrione and fluazifop-p-butyl. / Avaliaram-se os efeitos dos herbicidas mesotrione, fluazifop-p-butyl, fomesafen e fluazifop-p-butyl+fomesafen sobre as características fisiológicas de cultivares de mandioca. E também, a ação do mesotrione e do fluazifop-p-butyl na atividade microbiana do solo rizosférico de um dos cultivares. Para isso em quatro experimentos foram avaliadas: as características fisiológicas de cultivares de mandioca após a aplicação do mesotrione; a interferência do fluazifop-p-butyl e do fomesafen, em aplicações isoladas e em mistura sobre a eficiência do uso da água e características fotossintéticas dos cultivares de mandioca; e a ação do mestrione e do fluazifop-p-butyl sobre a atividade microbiana do solo rizosférico do cultivar Cacau- UFV aos 30 e 60 dias após aplicação dos herbicidas. O cultivar Platina foi mais tolerante ao mesotrione, enquanto o cultivar Coqueiro foi menos eficiente no uso da água sob aplicação deste herbicida. A taxa de transpiração, a condutância estomática e a eficiência do uso da água das plantas de mandioca aumentaram com o incremento das doses da mistura do fomesafen + fluazifop-p-butyl. Estes efeitos não foram observados quando os produtos foram aplicados isolados. Os cultivares de mandioca apresentam tolerância diferencial aos herbicidas fomesafen e fluazifop-p-butyl, sendo este o mais seletivo a cultura. Verificou-se aumento da colonização micorrízica das raízes avaliadas do cultivar Cacau-UFV aos 30 dias para ambos herbicidas e aos 60 dias apenas para o fluazifop-p-butyl; todavia, estes produtos não interferiram no qCO2. A cultura da mandioca foi mais tolerante aos herbicidas mesotrione e o fluazifop-p-butyl.
44

Análise tafonômica e paleoecológica de estruturas associadas a comunidades microbianas holocênicas e permianas / Taphonomic and paleoecological analysis of structures associated with holocen and permian microbial communities

Callefo, Flávia, 1983- 25 August 2018 (has links)
Orientador: Fresia Soledad Ricardi Torres Branco / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Geociências / Made available in DSpace on 2018-08-25T01:31:00Z (GMT). No. of bitstreams: 1 Callefo_Flavia_M.pdf: 11737292 bytes, checksum: 8072787b62f7e014cd2301d513fc4a17 (MD5) Previous issue date: 2014 / Resumo: Esteiras microbianas são estruturas organossedimentares laminadas, desenvolvidas a partir do acréscimo de lâminas de sedimentos aprisionados através do metabolismo de microrganismos, que induzem a precipitação de carbonato. Microbialitos são depósitos organossedimentares formados pela interação de microrganismos com sedimentos detríticos, através dos processos de trapeamento e aglutinação dos grãos e minerais. Esta pesquisa apresenta os resultados obtidos com o estudo tafonômico e paleoecológico de estruturas desenvolvidas por atividade de microrganismos, como estromatólitos, microbialitos e esteiras microbianas, com o intuito de comparar os resultados e traçar similaridades e diferenças nas relações ecológicas e ambientes de formação . Foram utilizados modelos recentes (Holoceno), como a Lagoa Salgada e Lagoa Pitanguinha, RJ, para compreender modelos fósseis (Permiano), afloramentos em Taguaí e Santa Rosa do Viterbo, SP. A metodologia se constituiu em análise de sedimentos associados, petrografia, análises composicionais (como MEV/EDS e Espectroscopia Raman) e estudo de campo. Foram levados em consideração os aspectos ambientais e biota contemporânea ao crescimento e desenvolvimento dos microbiais. As principais conclusões obtidas foram que os ambientes apresentam similaridades com relação a biota desenvolvida, bem como as relações ecológicas que estas mantinham com as comunidades microbianas responsáveis pelo desenvolvimento dos microbialitos e esteiras microbianas. O ambientes de crescimento das estruturas eram marinhos de águas rasas e hipersalinas, com o clima quente e alta taxa de evaporação. A alternância de eventos de tempestades e águas calmas, com posterior período de calmaria no qual foi possível o desenvolvimento de esteiras microbianas foram evidenciados no afloramento de Taguaí e na Lagoa Pitanguinha. Os microbialitos recentes da Lagoa Salgada sofreram maior influência de atividade de predação e herbivoria por parte de invertebrados, o que pode ter sido um fator relevante para a limitação do crescimento destas estruturas em comparação com aquelas existentes em Santa Rosa do Viterbo / Abstract: Microbial mats can be defined as laminated organosedimentary structures developed from the addition of laminaes of sediments trapped trough microorganisms metabolism, which leads to carbonate precipitation. Microbialites are organosedimentary deposits generated by the interation between microorganisms and detritic sediments through trapping and agglutination of minerals and grains play a key role. This research present the results of taphonomic and paleoecological studies from of structures developed by the activity of microorganisms such as microbialites, stromatolites and microbial mats aiming to comparison between the results obtained and to map similarities and differences on the ecological relations and formation environments. Recent models such as Salgada Lagoon and Pitanguinha Lagoon (Holocene), both located on Rio de Janeiro, were used to understand permian fossils models, outcrops located in Taguaí and Santa Rosa do Viterbo/SP. The methodology was based on the analysis of associated sediments, petrography and compositional analysis (MEV/EDS and Raman Spectroscopy) besides field studies. Aspects such as recent environments and biotas were considered to the analysis. The main conclusions were that the environments present similarities based on the development of the biotas as well as the ecological relations which those developed within the microbial communities responsible for the development of the microbialites and microbial mats. The growth environments of the structures were classified as shallow marine hypersaline waters, with warm weather and high evaporation rates. There was an alternation between storm events and calm waters. The growth of microbial mats became possible when the waters were predominantly calm evidenced by the outcrops from Taguaí and Pitanguinha Lagoon. The recent microbialites from Salgada Lagoon had a greater influence by activities from predators and herbivorous organisms such as invertebrates, which may be a relevant factor for the limitation growth of these structures when compared with those founded at Santa Rosa do Viterbo / Mestrado / Geologia e Recursos Naturais / Mestra em Geociências
45

Effet d’une pollution (métaux lourds et pesticides) et d’amendement (Fumier) sur les activités enzymatiques de différents sols

Sagna, Bacary 23 November 2009 (has links)
La fertilité, la pollution de l’écosystème sol sont devenues aujourd’hui des préoccupations etdes problèmes écologiques majeurs. L’objectif de cette étude est d’arriver à travers l’activitémicrobienne (hydrolyse de la FDA) et un large panel de 16 enzymes (phosphatases,hétérosidases, polysaccharidases, oligosaccharidases, oxydasses), à appréhender l’impact depolluants et d’amendement. Cinq sols aux caractéristiques physico-chimiques différentes ontété étudiés, et ont été soumis à différents traitements réalisés en microcosmes. Ces traitementsont porté sur l’ajout de zinc, cadmium, d’un herbicide, d’un insecticide, d’un fongicide, d’unnématicide et de fumier.L’expression des activités enzymatiques dépend fortement du type de sol. Ainsi lafraction limoneuse du sol jouerait un rôle crucial dans l’expression des enzymes telluriques. Parailleurs les résultats obtenus ont montré que des sols très proches d’un point de vu physicochimiquene le sont pas forcément au niveau enzymatique et microbien.L’ajout du fumier dans nos différents sols a entraîné quelque soit le type de sol defortes modifications positives des activités microbiennes et enzymatiques. L’effet stimulateurdu fumier sur l’activité microbienne et enzymatique dépend non seulement des paramètres dusol mais surtout de son activité initiale. Entre autre, l’impact positif du fumier est moinsmarqué dans les sols ayant des activités enzymatique ou des quantités de matière organiquefaibles. La tendance semble s’inversée concernant l’activité microbienne.L’impact des métaux lourds sur l’activité microbienne et les enzymes testées esttributaire des paramètres (argile, M.O), et de la nature des métaux lourds. Le cadmium s’avèreplus néfaste que le zinc. Si la majorité des activités enzymatiques sont diminuées par laprésence de métaux lourds d’autres en revanche ne sont pas impactées.La présence de pesticides dans nos sols révèle une grande disparité de résultat. Selon letype de sol, le type d’enzyme, une inhibition, un effet neutre ou bien une stimulation del’activité microbienne ou enzymatique par les pesticides ont été observés.Cette étude a permis de montrer que les enzymes sont très réactives aux différentesperturbations anthropiques quelque soit le type de sol considéré. Cependant cette réactivité setraduit par une très grande diversité des réponses. Cette diversité de réponse résulte d’ungrand nombre de paramètres liés aussi bien aux caractéristiques physico-chimiques quebiologiques du sol. Il n’a donc pas été possible de définir une enzyme ou groupe d’enzymesusceptible d’être utilisée comme indicateur pour l’ensemble des sols ou des traitements / Fertility and pollution of the soil ecosystem have become today’s concern and major ecologicalproblems. The objective ofthis study is to estimate through microbial activity (hydrolysis ofFDA) and a wide range of 16 enzymes (phosphatases, heterosidases, polysacchridases,oligosaccharidases, oxydase), the impact of pollutants and amendment in soil. The five soilsstudied are different regarding their physical and chemical characteristics. This soils are areexposed to different treatments in microcosms. These treatments consist to pollute our soilswith heavy metals (zinc, cadmium), pesticides (herbicide, insecticide, fungicide, nematicide)or to add manure.Our results showed that the expression of enzymatic activities depends on soil type.Thus, the silt fraction of soil plays a crucial role in this expression of soil enzymes. The soilswith physico-chemical characters are very similars, have not necessarily the same enzymaticprofile and expression or microbial activity.The presence of manure on our differents soils greatly increased the enzymatic andmicrobial activities. The stimulatory effect of manure depends on soil parameters but also theinitial enzymatic and microbial soil activities. The results showed that the positive impact ofmanure is less pronouncing in soils where the initial enzyme activity and organic matterquantity are low.The impact of heavy metals on microbial activity and enzymes tested depends on soilparameters (clay, organic matter, pH, ...) and nature of heavy metal. Cadmium is more toxicand longer decreases enzymatic and microbial activities than zinc. The presence of heavymetals in soils has reduced most of enzymes activity. Other enzymes are also unchanged orincreased by the pollutants.Soil pollution by pesticides show a large disparity and diversity of results. Dependingon soil type or the enzyme tested, the diffrents results showed an increase, neutral effect ordecrease by pesticides of enzymes and microbial activities.Watever the type of soil considered, this study has shown that soil enzymes are verysensitive and responsive to human disturbance. The reactivity of telluric enzymes is manifestedby a very large diversity of responses. Diversity responses of soil enzymes is depended tophysico-chemical characters and also soil biological parameters. In this study, it is verydifficult to define one or group of enzymes as a bioindicator for all soil disturbances
46

Washing and drying reusable sanitary pads

Sundberg, Fanny, Anderhell, Max January 2019 (has links)
Period poverty is a problem mainly found in places characterized by poverty. The lack of means for women and girls to properly handle their menstruation is the essence of the problem. With a lack of both quantity and quality regarding water often being an issue in such places, the hygiene is a constant challenge. Two different kinds of sanitary products are used globally, disposable and reusable. The reusable ones are often being made of cotton or other absorbent materials. Regardless the material, reusable products need cleaning between the times of use, which could be a challenge when water is not always accessible. To have a reusable sanitary pad that efficiently can be cleaned with low amounts of resources is important, especially in impoverished places. Spacerpad is a reusable sanitary pad and a part of a project at the University of Borås. The aim for the project is to reduce period poverty and to educate women and girls in menstrual hygiene management. The pad is made of polyester which does not absorb blood or water, instead the pad merely contains the fluids. This thesis was conducted as a field study in Nairobi, Kenya. The study aimed to simulate a menstruation, in order to analyze the microbial activity in two different reusable sanitary pads, during as well as after menstruation. With the influences from interviews and resources found in Kibera (a slum in Nairobi) a simulation of five days was executed, with nutrient solution instead of menstrual blood. The Spacerpad and a cotton pad were exposed to the same procedures and the effects of washing and drying were studied. The microbial activity was measured with the help of dipslides, a growth medium. The results of this study show that both Spacerpad and the cotton pad could be carriers of heavy growth of bacteria. Increasing microbial activity throughout the simulation as the days went by, ended with a dividing result after a soap wash as the final washing procedure. The pad made of cotton still carried above slight growth, compared to Spacerpad that showed almost no activity after the final cleanse. Even though the microbial activity reached high levels during the simulation, the fact that the Spacerpad can be cleaned with limited resources could be reason enough to consider the Spacerpad as a sufficiently sanitary product in an impoverished place like Kibera. / Mensfattigdom är något som vanligtvis återfinns på platser präglade av fattigdom. Bristen på medel för kvinnor och flickor att kunna hantera sin menstruation är kärnan av problemet. Med en brist i kvantitet och kvalitet på vatten som ett vanligt problem på sådana platser är det en konstant utmaning att upprätthålla sin hygien. Menstruationsskydd delas in i två olika typer, engångs- och återanvändningsbara produkter. De återanvändningsbara produkterna består ofta av bomull eller andra absorberande material. Oavsett material måste produkterna rengöras mellan användningarna, vilket kan vara en utmaning på platser där vatten inte alltid är tillgängligt. Tillgång till en återanvändningsbar binda som kan rengöras med små resurser är viktigt, speciellt på platser som kännetecknas av fattigdom. Spacerpad är en återanvändningsbar binda, framtagen som del av ett projekt vid Högskolan Borås, vars syfte är att reducera mensfattigdom och samtidigt utbilda kvinnor och flickor om menstruation och hygien. Bindan är tillverkad av polyester som inte absorberar blod eller vatten, vilket gör att bindan snarare håller vätskorna på plats. Denna uppsats gjordes som en fältstudie på plats i Nairobi, Kenya och hade som mål att simulera en menstruation. Detta för att se hur den mikrobiella aktiviteten skulle kunna se ut, under och efter en menstruation. Med influenser ur intervjuer och tillgångar från Kibera (ett slumområde i Nairobi) genomfördes simulationen med näringslösning som substitut till mensblod. I simulationen studerades effekten av tvätt och tork på den mikrobiella aktiviteten. Spacerpad och en bomullsbinda genomgick samma processer där aktiviteten mättes med hjälp av dipslides, ett växtmedium. Resultaten från denna studie visar att både Spacerpad och bomullsbindan kan vara bärare av hög tillväxt av bakterier. En ökande bakteriell aktivitet genom testdagarna, slutade med ett tudelat resultat efter en tvåltvätt som sista procedur. Bindan av bomull hade lätt tillväxt, medan Spacerpad knappt visade någon tillväxt alls efter den sista rengöringen. Den mikrobiella aktiviteten hos Spacerpad nådde höga nivåer under simulationen. Trots det så gör förmågan att kunna rengöras med låg åtgång av resurser, att den kan anses vara sanitär nog för att användas på platser präglade av fattigdom, som i Kibera.
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Environmental Implications of Cu-Based Nanoparticles and Biocides Products

Tegenaw, Ayenachew G., Ph.D. January 2019 (has links)
No description available.
48

Soil Fertility Status and Degradation of 2, 4, 6-Trinitrotoluene Contaminated Soils

Katseanes, Chelsea Kae 01 March 2014 (has links) (PDF)
Current models for predicting the environmental fate of munitions constituents (MC) in soils are based mostly on chemical distribution parameters and neglect the larger considerations of other soil parameters. We are working towards a new approach based on the whole soil activity for predicting the long-term residence time and fate of MC in soils with connection to agronomic soil fertility concepts. These relationships are demonstrated by correlating experiments involving full physical and chemical characterization of eight taxonomically distinct soils, with batch reactor studies determining MC degradation potential. Soils were incubated in a slurry for 10 days in a closed reactor system with temperature, pH, and Eh readings recorded every 24 h. Air and slurry samples were taken eight times within the 168 h incubation period. Carbon dioxide, TNT, and nutrient solution concentrations were assessed to obtain a full picture of soil chemistry changes associated with microbial activity in response to additions of TNT. Multivariate analysis was used to determine the main factors impacting degradation rate. Principle Components Analysis (PCA) statistically classified the soils based on the variance of their soil property data. Partial Least Squares Analysis (PLS) showed that TNT degradation was possibly correlated with soil fertility characteristics. Although this is an exploratory study, results show promise in moving towards a more effective way of predicting TNT environmental fate in soils.
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Mechanism of Positive, Non-Additive Litter Decomposition

Yin, Na 01 July 2019 (has links)
Litter decomposition is a fundamental ecosystem process. It is responsible for nutrient cycling and influences carbon (C) sequestration, and soil physical and chemical properties. In nature, litter is usually heterogeneous and may not decompose the way homogeneous litter does. For example, heterogeneous litter decomposition is frequently non-additive. This makes the rate of nutrient cycling as well as fluxes of C into and out of soil C pools impossible to predict. The most frequently proposed mechanisms for positive, non-additive decomposition include the supply of limiting mineral nutrients, the supply of available C (priming), and the improvement of micro-environmental conditions. However, all three mechanisms are controversial in the sense that no single mechanism accounts for all cases of non-additive decomposition. In mesic ecosystems, both soil microbes and soil fauna are the major causes of decomposition. Microbes decompose litter by producing extracellular enzymes. The comminution of litter by soil animals interacts with microbial activities by increasing substrate surface area. In our study, positive, non-additive decomposition of oat straw when mixed with clover was not due to enhancing microarthropod density in oat straw but associated with significantly increased microbial activity in oat straw. We further investigated the factors that contribute to positive, non-additive decomposition by testing several common hypotheses used to explain non-additive decomposition (increased water content, and the transfer of C and/or nitrogen (N) compounds from clover to oat straw). We also tested a new hypothesis, which is that C, N and other nutrients are simultaneously supplied by clover to stimulate the decomposition of oat straw. Our study indicated that the addition of water to oat straw did not increase oat straw decomposition and adding ammonium chloride only or glucose and ammonium chloride together to oat straw had no significant effect on oat straw decomposition. Glucose addition alone (Low concentration) increased oat straw decomposition but was not sufficient to predict the effect of clover litter. Either the addition of glucose, ammonium chloride and other minerals together to oat straw, or soil was in contact with oat straw and glucose and ammonium chloride were added, oat straw decomposition was stimulated as if clover were present. These results suggest that the limiting resources are some combination of C, N and other mineral nutrients and that soil itself may be a source of limiting nutrients in litter decomposition. In nature, some combination of high quality litter and soil itself may supply resources that stimulate the decomposing organisms’ activity on low quality litter and then the decomposition of low quality litter. Our research provides insight into the dynamics of heterogeneous litter decomposition and will allow us to better model nutrient cycling.
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Microbial Nitrogen Cycling Response to Calcium and Phosphorus in Northern Hardwood Forest Soils at the Hubbard Brook Experimental Forest, New Hampshire

Minick, Kevan J. 11 December 2009 (has links)
No description available.

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