abstract: DehaloR^2 is a previously characterized, trichloroethene (TCE)-dechlorinating culture and contains bacteria from the known dechlorinating genus, Dehalococcoides. DehaloR^2 was exposed to three anthropogenic contaminants, Triclocarban (TCC), tris(2-chloroethyl) phosphate (TCEP), and 1,1,1-trichloroethane (TCA) and two biogenic-like halogenated compounds, 2,6-dibromophenol (2,6-DBP) and 2,6-dichlorophenol (2,6-DCP). The effects on TCE dechlorination ability due to 2,6-DBP and 2,6-DCP exposures were also investigated. DehaloR^2 did not dechlorinate TCC or TCEP. After initial exposure to TCA, half of the initial TCA was dechlorinated to 1,1-dichloroethane (DCA), however half of the TCA remained by day 100. Subsequent TCA and TCE re-exposure showed no reductive dechlorination activity for both TCA and TCE by 120 days after the re-exposure. It has been hypothesized that the microbial TCE-dechlorinating ability was developed before TCE became abundant in groundwater. This dechlorinating ability would have existed in the microbial metabolism due to previous exposure to biogenic halogenated compounds. After observing the inability of DehaloR^2 to dechlorinate other anthropogenic compounds, DehaloR^2 was then exposed to two naturally occurring halogenated phenols, 2,6-DBP and 2,6-DCP, in the presence and absence of TCE. DehaloR^2 debrominated 2,6-DBP through the intermediate 2-bromophenol (2-BP) to the end product phenol faster in the presence of TCE. DehaloR^2 dechlorinated 2,6-DCP to 2-CP in the absence of TCE; however, 2,6-DCP dechlorination was incomplete in the presence of TCE. Additionally, when 2,6-DBP was present, complete TCE dechlorination to ethene occurred more quickly than when TCE was present without 2,6-DBP. However, when 2,6-DCP was present, TCE dechlorination to ethene had not completed by day 55. The increased dehalogenation rate of 2,6-DBP and TCE when present together compared to conditions containing only 2,6-DBP or only TCE suggests a possible synergistic relationship between 2,6-DBP and TCE, while the decreased dechlorination rate of 2,6-DCP and TCE when present together compared to conditions containing only 2,6-DCP or only TCE suggests an inhibitory effect. / Dissertation/Thesis / M.S. Civil and Environmental Engineering 2012

abstract: Human activity has increased loading of reactive nitrogen (N) in the environment, with important and often deleterious impacts on biodiversity, climate, and human health. Since the fate of N in the ecosystem is mainly controlled by microorganisms, understanding the factors that shape microbial communities becomes relevant and urgent. In arid land soils, these microbial communities and factors are not well understood. I aimed to study the role of N cycling microbes, such as the ammonia-oxidizing bacteria (AOB), the recently discovered ammonia-oxidizing archaea (AOA), and various fungal groups, in soils of arid lands. I also tested if niche differentiation among microbial populations is a driver of differential biogeochemical outcomes. I found that N cycling microbial communities in arid lands are structured by environmental factors to a stronger degree than what is generally observed in mesic systems. For example, in biological soil crusts, temperature selected for AOA in warmer deserts and for AOB in colder deserts. Land-use change also affects niche differentiation, with fungi being the major agents of N2O production in natural arid lands, whereas emissions could be attributed to bacteria in mesic urban lawns. By contrast, NO3- production in the native desert and managed soils was mainly controlled by autotrophic microbes (i.e., AOB and AOA) rather than by heterotrophic fungi. I could also determine that AOA surprisingly responded positively to inorganic N availability in both short (one month) and long-term (seven years) experimental manipulations in an arid land soil, while environmental N enrichment in other ecosystem types is known to favor AOB over AOA. This work improves our predictions of ecosystem response to anthropogenic N increase and shows that paradigms derived from mesic systems are not always applicable to arid lands. My dissertation also highlights the unique ecology of ammonia oxidizers and draws attention to the importance of N cycling in desert soils. / Dissertation/Thesis / Ph.D. Biology 2013

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / This research aimed to analyze the use and / or the employ of the word interdisciplinarity carried out by graduate students of the Graduate Program in Development and Environment of the Federal University of Sergipe in the last 12 years ( 2003-2014 ) . The study focus on the analysis of theoretical elements, methodological and / or paradigm corresponding to the interdisciplinarity notion present in dissertations. Two hundred and forty-nine dissertations were analyzed. It adopted the discursive approach Pêcheux, French Discourse Analysis (ADF), for the analysis and processing of information . The interaction in the research took place from participating actively, in the sense that the author is located in socio- historical reality studied. The main results of the research explain that interdisciplinarity is taken consensually as a guiding principle; this approach is presented in the interdisciplinary training of research, course design, the interaction in the classroom, in management meetings and field work carried out by coordination, staff, teachers and students. However, in dissertations, employ and / or the use of the term interdisciplinarity shows five major characteristics: a) there are differences in the concept of the management of research (confusion content); b) is predominant theoretical dimension of interdisciplinarity (cognitive consensus); c) there is no specific methodological design to interdisciplinarity (pragmatic nullity); d) there is adoption of sustainability as a matrix, reference and / or index the interdisciplinary analysis (instrumental inversion); e) elects to interdisciplinarity as a criterion for measuring learning. We conclude that the use and / or the employ of interdisciplinarity are restricted to the theoretical dimension and are associated with the evaluation process of academic education. This reduction obscures the identification of methodological aspects, suitable to characterize and justify the relevance of interdisciplinarity in carrying out the dissertations analyzed. / Esta pesquisa teve como objetivo analisar o uso e/ou emprego da palavra interdisciplinaridade realizado pelos estudantes de mestrado do Programa de Pós-graduação em Desenvolvimento e Meio Ambiente da Universidade Federal de Sergipe nos últimos 12 anos (2003-2014). O estudo concentra-se na análise de elementos teóricos, metodológicos e/ou paradigmáticos correspondentes à noção de interdisciplinaridade presente em dissertações. Duzentas e quarenta e nove dissertações foram analisadas. Adotou-se a abordagem discursiva de Pêcheux, Análise do Discurso Francesa (ADF), para a análise e tratamento das informações. A interação na pesquisa ocorreu de modo participante-ativo, no sentido de que a autora situa-se na realidade sócio-histórica estudada. Os principais resultados da pesquisa explicitam que a interdisciplinaridade é assumida consensualmente como um princípio norteador, esta postura se apresenta na formação interdisciplinar de pesquisa, no projeto de curso, nas interações em sala de aula, nas reuniões de gestão e no trabalho de campo efetuados por coordenação, funcionários, professores e alunos. No entanto, nas dissertações produzidas, o emprego e/ou uso do termo interdisciplinaridade demonstra cinco características principais: a) existem divergências no manejo do conceito entre as pesquisas (confusão de conteúdo); b) é predominante a dimensão teórica da interdisciplinaridade (consenso cognitivo); c) não existe delineamento metodológico específico à interdisciplinaridade (nulidade pragmática); d) existe adoção da sustentabilidade como matriz, referência e/ou índice à análise interdisciplinar (inversão instrumental); e) elege-se a interdisciplinaridade como um critério de mensuração da aprendizagem. Conclui-se que o emprego e/ou uso da interdisciplinaridade se encontram restritos à dimensão teórica e associados ao processo avaliativo da formação acadêmica. Tal redução obscurece a identificação de aspectos metodológicos, adequados para caracterizar e justificar a relevância da interdisciplinaridade na realização das pesquisas analisadas.

Made available in DSpace on 2015-04-11T13:54:01Z (GMT). No. of bitstreams: 1 andre.pdf: 5607128 bytes, checksum: 17175736a2095384fe44e019d20dccf7 (MD5) Previous issue date: 2012-10-17 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The emergence of interdisciplinary themes has opened new possibilities for scientific approach to reality. In the Amazon, where the relations between society and nature are evident, interdisciplinarity is essential in order to grasp complex issues. The Environmental Science, which brings in its essence the interdisciplinary approach, is in process of construction in terms of theoretical and methodological procedures favoring innovative research. The issue of networks, Catfishes and its relationship with the cities is a matter interdisciplinary environmental science can give an alternative approach. In this sense the present study proposes an investigation summarized in the following question: How can environmental science contribute to the analysis of the problems of fisheries and conservation of stocks of catfish in the Amazon? A hypothesis is formulated: the integration of the studies of networks, market structure, cities and catfishes will develop elements that integrate conservation with responsible use (socially just and ecologically friendly) of fishery resources. To collect the data, we conducted field work between May 17 and July 15, 2011 in eleven cities in the Upper and Middle Solimões River in Amazonas state, Brazil, visiting a total of 47 floating strutures that commercialize and stock catfishes which corresponds to 92.16% of the total. Semi-structured interviews about infrastructure, labor relations, among other flows was realized. The main results were 1) the market network of Catfish has intrinsic relationship to urban network; 2) necessary to describe in detail the important level of network flows and consider its particularities, and 3 ) along these there are political, social and cultural links that establish an intricate network essencial for the understanding and conservation of Catfishes. The network comprises a reality whose complexity is reflected in the difficulty of translating it scientifically. The proposition of theoretical and methodological instruments (open interdisciplinary approach, juxtaposing objects and conceptual fragmentation of the object) consisted in an attempt to elucidate the object and decifring the results. This research is an interdisciplinary dialogue and represents an alternative integrated vision by which it has drawn the research on Catfishes and cities. / A emergência da questão interdisciplinar tem aberto novas possibilidades de abordagem científica da realidade. Na Amazônia, onde as relações entre sociedade e natureza são evidentes, esse contexto é propício para novas problematizações para questões de difícil apreensão. A Ciência Ambiental, que traz em sua essência a proposta interdisciplinar, encontra-se em processo de construção em termos teórico-metodológicos de forma favorável a pesquisas inovadoras. A questão da rede de comercialização de Bagres e sua relação com as cidades representa uma questão interdisciplinar ambiental que pode levantar elementos importantes para a questão ambiental na Amazônia com outro olhar. Nesse sentido o presente estudo se propõe a uma investigação que se sintetiza na seguinte pergunta: De que forma a ciência ambiental pode contribuir para a análise da problemática da pesca e da conservação dos estoques de bagres na Amazônia? Como hipótese tem-se que o estudo da rede de comercialização da pesca permitirá elaborar elementos que integrem conservação com uso responsável (socialmente justo e ecologicamente correto) dos recursos pesqueiros. Para a coleta dos dados, foi realizado um trabalho de campo entre os dias 17 de maio e 15 de julho em onze cidades do Alto e Médio Solimões visitando um total de 47 frigoríficos flutuantes o que corresponde a 92,16% para entrevistas semiestruturadas sobre a infraestrutura, relações de trabalho, fluxos entre outras. Os principais resultados deram conta de 1) ratificar que a rede de comercialização de Bagres tem relação intrínseca com a rere urbana da calha do Rio Solimões; 2) descrever em importante nível de detalhamento os fixos e os fluxos da rede considerando suas particularidades; e 3) apresentando os aspectos políticos, sociais e culturais que constituem a rede buscando a forma como isso ocorre. A rede compõe uma realidade cuja complexidade se traduz na dificuldade de traduzi-la deforma científica. A proposição de instrumentais teórico-metodológico (abordagem interdisciplinar aberta, justaposição de objetos e fragmentação conceitual do objeto) consistiu numa tentativa de elucidar o objeto e fora decisivos nos resultados obtidos. Essa pesquisa constitui um diálogo interdisciplinar e representa uma alternativa integrada na visão pelo qual se tem desenhado as pesquisas em Bagres e cidades.

<p> Impacts of climate change on the already severely strained freshwater resources of approximately 1000 inhabited islands in the Pacific Ocean are of great concern. The Western Pacific region is one of the world&rsquo;s most vulnerable when it comes to risk of disaster particularly for the several of the low-lying coral islands. Impacts have already been felt regarding the security of water resources that would directly impact agriculture, forestry, tourism and other industry-related sectors. The ironic and tragic aspect of the environmental crisis of greenhouse emissions is the fact that those parts of the world least responsible for creating the water security issues are the first to suffer its consequences. Pacific Island Nations are responsible for only 0.03 percent of the world&rsquo;s carbon dioxide emissions, and the average island resident produces only one-quarter of the emissions of the average person worldwide. </p><p> Utilizing the historical data, the evidence of change in water quality and access on Guam has been examined. All indicators except for the precipitation support the hypotheses that climate change trends are impacting Guam&rsquo;s water security. This will eventually weaken Guam&rsquo;s resilience. As a result of this research and its recommendations, a sustainable freshwater resources management plan, for a water-secured Guam can be produced. Adaptive management provided here is based on a process that can measure the resilience of Guam to the issue of water security.</p><p>

Mercury (Hg) is a toxic heavy metal that poses significant human and environmental health risks. Mineral-associated Hg is the largest reservoir of Hg in the environment where it can account for nearly 60% of the global Hg mass inventory. A large fraction of this pool is comprised of mercury sulfide (HgS) minerals, including metacinnabar (beta-HgS). HgS minerals have long been considered insignificant sources of Hg to aqueous or atmospheric pools in all but severely acidic environments due to their low solubility and slow abiotic dissolution kinetics. Little previous work has been conducted investigating the bacterial colonization of HgS minerals and the potential role of these mineral-associated communities in impacting the mobility of mineral-hosted Hg. To address this gap in knowledge, the studies within this dissertation employed a combination of field- and laboratory-based methods. Using culture-independent techniques, this work revealed that sulfur-oxidizing bacteria can extensively colonize metacinnabar within aerobic, near neutral pH, creek sediments, suggesting a potential role for chemolithotrophic bacteria in metacinnabar weathering. Within laboratory incubations, the dominant bacterial colonizer (Thiobacillus thioparus), induced extensive release and volatilization of metacinnabar-hosted Hg. These findings expose a new pathway for metacinnabar dissolution and point to mineral-hosted Hg as an underappreciated source of elemental Hg that may contribute to global atmospheric Hg budgets. In addition, this work elucidates the importance of thiosulfate, a major intermediate sulfur species in the environment, in stimulating metacinnabar dissolution. Therefore, the work within this dissertation shows that authigenic HgS minerals are not merely a sink for Hg within non-acidic natural environments and instead are a source of dissolved and gaseous Hg. This work provides critical information for predicting the transport of Hg in the environment and for developing appropriate management and remediation strategies for Hg-contaminated systems. / Engineering and Applied Sciences

This study involves tracing inputs, partitioning, and outputs of phosphorus (P) through an aquaponics system. A mathematical model was developed to describe the dynamics of phosphorus in an aquaponics nutrient solution, and to maximize P use efficiency and minimize P waste. We assessed the influence of pH on the availability and speciation of phosphorus in an aquaponics nutrient solution. By using Visual MINTEQ, a freeware chemical equilibrium model for the calculation of element speciation, solubility equilibria, and sorption for natural waters, it was discovered that high pH values favor the formation of calcium phosphate complexes, decreasing the concentration of free phosphorus in aquaponics nutrient solutions. In addition, the mineralization of organic phosphorus in aquaponics systems was evaluated using treatments with phytase supplementation to fish diets, and incorporation of a microbial inoculant in the aquaponics nutrient solution. Overall, dietary phytase and microorganisms promoted phosphorus mineralization and enhanced phosphorus utilization in aquaponics systems. In the end, we conclude that aquaponics systems can keep the same growth performance and quality of vegetable crops grown in conventional systems when the availability and dynamics of phosphorus are well managed.

Landscape position and depth in the soil column influence the movement of microbial substrate throughout a catchment, from upslope areas to downslope areas, thereby impacting nutrient cycling rates and capabilities of the microbial communities in those areas. Wildfire also shapes the biogeochemistry of the landscape, creating a mosaic with variations in substrate type and concentration that also influence microbial communities and biogeochemical cycling. Nitrogen (N) in particular is altered by wildfire, as it is easily volatilized and the removal of organic matter (OM) reduces N inputs. We aimed to understand how landscape position and soil depth, first and foremost, influence microbial communities and their N-cycling, but also how this may differ from wildfires and their relative impacts on the soil microbial communities. Landscape position proved to influence few soil and microbial characteristics, while movement from soil surface to deep in the column and the incidence of wildfire caused many variations in soil physical and biogeochemical cycling properties. The interaction of landscape position and soil depth also showed little variation in any measurements, while wildfire and soil depth interactions showed drastic changes that indicate high order controls over the soil microbial community. It can be surmised that while landscape position is important for many soil properties, it is soil depth and wildfire that truly control the soil microbial communities and their N-cycling capabilities.

This case study was undertaken to determine if the mission of the Regional Planning Program at Western State College is being fulfilled. The mission states that the Regional Planning Program should offer interdisciplinary, or integrated, education. The problem is the course work in the Regional Planning Program has become very specialized, creating fragmented education. The research methods, including historical review and in-depth interviews, indicate several findings that support the recommendation for a reorganization of the curriculum at Western State to implement interdisciplinary study. First, an historical analysis of the transformation of the college mission during the early 1900s reveals two major themes. One theme is the need for change in the academic programs to include practical applications. The justification for the creation of the Regional Planning Program at Western was based on the pragmatic aspects of the program. The other theme is the need for integrated education, or education that incorporates the theoretical with practical applications from several related disciplines, to solve problems. The historical review of the Regional Planning Program shows that integrated education is not being offered. Second, a review of the literature on interdisciplinary teaching, or cross-principles teaching, was conducted to determine how interdisciplinary programs are structured and how the Regional Planning Program at Western State compares to these programs. It was found that the interdisciplinary teaching techniques and curricular structure described in the literature are not part of the Regional Planning Program. Third, a series of in-depth, unstructured interviews were conducted with five professors. Two professors are members of the Regional Planning and Geography Department. The other three professors are members of the History, Biology, and Business/Economics Departments. It was found that these professors teach traditional, disciplinary courses. It was concluded from the case study that regional planning at Western State is not treated as an interdisciplinary field. Although the data indicate that the professors believe the Regional Planning Program should offer an integrated education, there have been few attempts to integrate course work. A reorganization to create an interdisciplinary approach at Western State is put forth in the conclusion.

abstract: Nitrous oxide (N2O) is an important greenhouse gas and an oxidant respired by a diverse range of anaerobic microbes, but its sources and sinks are poorly understood. The overarching goal of my dissertation is to explore abiotic N2O formation and microbial N2O consumption across reducing environments of the early and modern Earth. By combining experiments as well as diffusion and atmospheric modeling, I present evidence that N2O production can be catalyzed on iron mineral surfaces that may have been present in shallow waters of the Archean ocean. Using photochemical models, I showed that tropospheric N2O concentrations close to modern ones (ppb range) were possible before O2 accumulated. In peatlands of the Amazon basin (modern Earth), unexpected abiotic activity became apparent under anoxic conditions. However, care has to be taken to adequately disentangle abiotic from biotic reactions. I identified significant sterilant-induced changes in Fe2+ and dissolved organic matter pools (determined by fluorescence spectroscopy). Among all chemical and physical sterilants tested, γ - irradiation showed the least effect on reactant pools. Targeting geochemically diverse peatlands across Central and South America, I present evidence that coupled abiotic and biotic cycling of N2O could be a widespread phenomenon. Using isotopic tracers in the field, I showed that abiotic N2O fluxes rival biotic ones under in-situ conditions. Moreover, once N2O is produced, it is rapidly consumed by N2O-reducing microbes. Using amplicon sequencing and metagenomics, I demonstrated that this surprising N2O sink potential is associated with diverse bacteria, including the recently discovered clade II that is present in high proportions at Amazonian sites based on nosZ quantities. Finally, to evaluate the impact of nitrogen oxides on methane production in peatlands, I characterized soil nitrite (NO2–) and N2O abundances along soil profiles. I complemented field analyses with molecular work by deploying amplicon-based 16S rRNA and mcrA sequencing. The diversity and activity of soil methanogens was affected by the presence of NO2– and N2O, suggesting that methane emissions could be influenced by N2O cycling dynamics. Overall, my work proposes a key role for N2O in Earth systems across time and a central position in tropical microbial ecosystems. / Dissertation/Thesis / Doctoral Dissertation Microbiology 2020