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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.
241

Caracterização dos meios de cultivo de viveiros de carcinicultura e da lagoa de disposição dos efluentes no Rio Grande do Norte: subsídios para proteção dos ecossistemas deste estudo / Characterization of shrimp ponds and effluents sedimentation pond in Rio Grande do Norte: subsidies to the protection of the ecosystems in this study

Cunha, Paulo Eduardo Vieira 04 March 2005 (has links)
O cultivo de camarões é uma importante atividade econômica em zonas costeiras de muitos países. No Brasil, a carcinicultura teve início no Rio Grande do Norte em 1973 e, atualmente, consolida-se como principal produto da pauta de exportação desse estado, sucesso devido principalmente ao seu clima semi-árido, à vasta costa litorânea com extensas áreas estuarinas e lagoas costeiras, à topografia e ao solo, todos eles fatores adequados a essa atividade. A carcinicultura exerce importante papel sócio econômico, ético e de cidadania por: criar empregos em diferentes níveis de trabalho; minimizar os índices de pobreza; incentivar a dieta alimentar rica em proteínas além de, drasticamente, reduzir a superexploração de recursos naturais costeiros. O custo deste empreendimento é o árduo contraponto de ordem ambiental - a indiscutível necessidade de proteger os ecossistemas dos quais fazem parte as fazendas de camarão - única forma de essa atividade garantir sua sustentabilidade. Para impedir o desequilíbrio ecológico é preciso haver permanente monitoramento dos ecossistemas, como forma de evitar a desestabilização ambiental - devida ao desordenado uso e ocupação do solo nos ecossistemas - e garantir que as fazendas continuem produtivas. Com o propósito de fornecer subsídios para a sustentabilidade da carcinicultura, neste trabalho foi realizada a caracterização físico-química dos ecossistemas que compõem as fazendas de cultivo - manancial e captação, viveiros e seus efluentes - segundo os parâmetros estabelecidos pela resolução nº 312 do CONAMA, de 10 de outubro de 2002. Especial atenção foi dada à lagoa de decantação, por terem sido constatadas necessidades de adequações para seu correto funcionamento. A hipótese que os efluentes de carcinicultura não tem características que permitam seu descarte em corpos de água por não atenderem aos padrões estabelecidos na legislação brasileira, foi confirmada em função das altas concentrações de DBO. Essa hipótese, testada com o objetivo da concluir da necessidade ou não do uso da bacia de sedimentação para tratamento dos referidos efluentes, indicou ser imprescindível a existência desse sistema para promover a decantação de material sólido e a estabilização da matéria orgânica. / The shrimp culture is an important economic factor in coast areas in a lot of countries. In Brasil, the carcinicultura starts in Rio Grande do Norte in 1973, and actually shrimp is the principal commodity of exportation, specially because of climatic conditions, spread coast area and topography. This activity carries out an important social-economic development, although causes environmental impacts. The environmental monitory is an important tool to maintain the ecological equilibration. This research proposes subsidy the sustentability of carcinicultura by studying the physical-chemical characterization of the culture ecosystems, that composes the farm according to the variables established in the CONAMA resolution nº 312. Special attention was given to the sedimentation pond, because it needs to its best function. It was observed that carcinicultura wastewater can\'t be discarded without treatment, because they don\'t attend what is established in the brazilian legislation, due of BOD concentrations.
242

Utilização de lodo de lagoa de estabilização na cultura de sorgo granífero (Sorghum bicolor, L. Moench) em condições de casa de vegetação / not available

Silva, Nelson Luiz da 18 May 2001 (has links)
O presente trabalho teve como objeto avaliar os efeitos da aplicação de doses crescentes de lodo de esgoto de lagoas anaeróbias sobre a fertilidade do solo, disponibilidade de metais pesados no solo e produção de matéria seca, acúmulo de nutrientes e metais pesados em plantas de Sorghum bicolor L. (Moench). Os tratamentos testados foram: 1) Testemunha; 2) Fertilização Mineral; 3) L100 - Lodo de esgoto em quantidade suficiente para fornecer o nitrogênio exigido pela cultura; 4) L200 - O dobro da quantidade de lodo aplicada no tratamento 3; 5) L300 - O triplo da quantidade de lodo aplicada no tratamento 3. O experimento foi conduzido por 124 dias, em condições de casa de vegetação, sendo que o delineamento estatístico foi o bloco casualizados com 5 tratamentos e quatro repetições, totalizando 20 parcelas. Os resultados obtidos foram submetidos à análise de variância (Teste F) e, nos casos pertinentes as médias foram comparadas pelo Teste Tukey a 5% de probabilidade. Procedeu-se à realização da análise de regressão linear entre as variáveis estudadas e as doses de lodo de esgoto. Considerando-se os resultados obtidos no presente trabalho, foi possível elaborar as seguintes conclusões: - A incorporação do lodo de esgoto no solo proporcionou melhorias de algumas variáveis consideradas na avaliação da fertilidade do solo, podendo-se citar: teor de Matéria Orgânica, teor de fósforo disponível, potássio disponível e capacidade de troca de cátions. - Por outro lado, algumas variáveis, também relacionadas a fertilidade do solo, sofreram prejuízos, podendo-se citar: pH, teores de cálcio disponível, magnésio disponível e saturação por bases. Todos os elementos metálicos pesados, presentes no lodo de esgoto tiveram suas disponibilidades aumentadas no solo. - O lodo de esgoto promoveu maior produção de biomassa vegetal de ramos e folhas, panículas e raízes. - O aumento da dose de lodo proporcionou decréscimo no acúmulo de P nas ) nas folhas e ramos das plantas de sorgo granífero. Porém, nas outras partes analisadas houve aumento do acúmulo de P. Os totais acumulados de Ca e Mg não foram influenciados pelas dose de lodo de esgoto. Para os demais macronutrientes, o aumento da dose de lodo de esgoto resultou em maior acúmulo nas plantas. - Todos os metais presentes no lodo de esgoto tiveram seus acúmulos aumentados nas diferentes partes das plantas de sorgo granífero , com o aumento das doses de lodo incorporadas nos solos. Entretanto, nenhum teor encontrado foi alto o suficiente para proporcionar o surgimento de sintomas de toxicidade nas plantas. - O lodo de esgoto apresentou bom desempenho como fonte de micronutrientes para as plantas de sorgo granífero. / The object of this study was to evaluate the effects of an application of ever increasing doses of sewer mud of anaerobic ponds on soil fertiliy, the avaliability of metals in the soil, the production of dry material, the accumulation of nutrients and heavy metals in the plant, Sorghum bicolor L (Moench). The treatments tested were: 1) Witness; 2) mineral fertilization; 3) L100 - Sewer mud in sufficient quantities to provide the nitrogen required by the culture; 4) L200 - a double quantity of sewer mud applied is the treatment 3; 5) L300 - a triple quantity of sewer mud applied in the treatment 3. The experiment was conducted for 124 days in vegetation house conditions. The estatistical delineation used was that of causalized blocks of tive treatments and four repetitions, totaling 20 blocks. The abtained results were submitted to an analysis of variance (Test F) and in the pertinant cases, the averages were compared by the Tukey Test for a 5% probality. An analysis of the linear regression between the stuied variables and the doses of sewer mud were conducted. With the results obtained in this study, it was possible to e1aborate the following conclusions: - The incorporation of the sewer mud in the soil provided improvement is some variables used in the evaluation of the soil fertility; variables such as the contents of Organic Matter, the contents of avaliable Phosphorus, the contents of available Potassium and the capacity for cation exchange. - On the other hand, some variables related to soil fertility suffered losses; variables such as pH, the contents of available Calcium, of available Magnesium and base saturation. - All the heavy metal elements, present in the sewer mud, had their availability increased in the soil. - The sewer mud promoted a large production of vegetal biomass of branches, leaves, panicles and roots. - The increase of the sewer mud dose promoted the decrease in the accumulation of P in the leaves and branches of the grair producing sorghum plant. But, for the other parts analyzed, there was an increase in the accumulation of P, the accumulated totais af Calcium and Magnesium weren\'t influncied by the sewer mud dose. For the other macronutrients the increase dose of sewer mud resulted in larger accumulations in the plants. - All the heavy metals present in the sewer mud had their accumulations increased in the different parts of the grain producing sorghum plants, with the increased doses of sewer mud incorparated in the soil. However, none of contents found were high enough to promote the appearance of toxin symptons in the plants. - The ewer mud presented a good performance as a source of micronutrients for the grain producing sorghun plants.
243

Characterisation of microbial Mat communities in meltwater ponds of the McMurdo ice shelf, Antarctica

Jungblut, Anne Dorothee, Biotechnology & Biomolecular Sciences, Faculty of Science, UNSW January 2007 (has links)
The investigation presented in this thesis examined the microbial and functional diversity of the meltwater ponds Fresh, Orange and Salt Ponds on the McMurdo Ice Shelf, near Bratina Island, Antarctica. These sites were chosen because of the ecological importance and absence of detailed characterisations of their diversity and function as part of Antarctica?s largest wetland. Particular focus was on cyanobacterial diversity, nitrogen fixation and secondary metabolite production. Using 16S rRNA gene and morphological analysis a large diversity of cyanobacteria (more than 22 phylotypes) was identified with high phylogenetic similarities (up to 99% sequence identity) to cyanobacteria from mats in other regions of Antarctica. In addition biogeographical distributions were identified including potentially endemic and cosmopolitan cyanobacteria. High salinities were also connected to the change and reduction of diversity. Lipid marker analyses were performed targeting hydrocarbons, ether-linked hydrocarbons, methylated fatty acid esters (FAME), wax esters, hopanols and sterols. Lipid biomarker profiles were similar to typical cyanobacteria dominated mats with major input from microorganisms including oxygenic and anoxygenic phototrophs, obligate aerobic and anaerobic heterotrophs that conduct the metabolic processes of fermentation, sulphate reduction, sulphate and iron-oxidation, methanogeneses. Signature lipids indicative of Chloroflexus and archaea, as well as branched aliphatic alkanes with quaternary substituted carbon atoms (BAQCs), were identified for the first time in Fresh, Orange and Salt Ponds. Based on nifH gene analysis, the nitrogen fixing diversity characterised in Orange Pond consisted of cyanobacterial Nostoc sp. as well as firmicutes, beta-, gamma- and delta-proteobacteria. Acetylene reduction assays and nifH gene RNA transcript diversity identified Nostoc sp. as a main contributor of nitrogenase activity in these ponds. Furthermore, analytical methods were used to identify the cyanobacterial secondary metabolites microcystins, although the genetic basis for this production and the toxin producer could not been identified. However non-ribosomal peptide synthetases (NRPS) and polyketide synthases (PKS) genes were identified which could be the genetic basis for novel bioactives. The use of a multi-disciplinary approach synthesis and subsequent results significantly increased our understanding of the diversity and function of microbial mat communities in the unique meltwater ponds of the McMurdo Ice shelf, Antarctica.
244

Effects of hydrology on zooplankton communities in high mountain ponds, Mount Rainier National Park

Girdner, Scott F. 06 April 1994 (has links)
Ten high mountain ponds in Mount Rainier National Park, Washington State, were studied from June through September 1992 to investigate the influences of fluctuating pond volumes on zooplankton communities. A temporary pond of short wet phase duration was inhabited by zooplankton taxa with short generation times and a crustacean taxa with the ability to encyst as drought-resistant resting bodies at immature stages of development. Relative to permanent ponds, rotifer densities typically were low in temporary ponds, although Brachionus urceolaris was abundant shortly before the ponds dried. High volume loss was associated with declining populations of crustaceans. Daphnia rosea was not present in the crustacean communities of temporary ponds after fall recharge. Deep-permanent ponds had slower copepod development and two additional large bodied crustacean taxa relative to shallow-permanent ponds. Because of their small sizes and sensitivity to environmental change, ponds such as these may provide an early signal of changes in aquatic systems from global warming. / Graduation date: 1994
245

Primary Production and Nutrient Dynamics of Urban Ponds

Rolon dos Santos Mérette, Muriel 01 February 2012 (has links)
In urban areas, stormwater management ponds (SWPs) are built to mitigate polluted runoff. Although these ponds are increasing in numbers, their ecology is not well understood. Physical and chemical characteristics of 17 SWPs in the City of Ottawa were measured to determine the drivers of phytoplankton biomass (Chl. a) and primary production (PP). While total phosphorus was the best predictor of algal biomass in the ponds (as in lakes), the imperviousness of the catchment could also predict Chl. a. Planktonic PP in two ponds measured seasonally was more closely related to water residence time than to nutrient concentrations with rates approaching at times the theoretical maximum for aquatic systems. In one pond, whole ecosystem metabolism, estimated using diel changes in dissolved oxygen and δ18O-O2, suggested that these hypereutrophic systems were net sinks for carbon in the summer but likely sources to the atmosphere at other times of the year.
246

Biodiversity and ecosystem functioning in created agricultural wetlands

Thiere, Geraldine January 2009 (has links)
This doctoral dissertation was produced in a cooperation between Halmstad University (Wetland Research Centre, School of Business and Engineering) and Lund University (Limnology &amp; Marine Biology, Department of Ecology). Abstract . Wetland creation at large, regional scales is implemented as a measure to abate the biodiversity loss in agricultural landscapes and the eutrophication of watersheds and coastal areas by non-point source nutrient pollution (mainly nitrogen). The consequences of creating many new wetlands for biodiversity conservation and nutrient reten- tion (ecosystem functioning) in agricultural landscapes are still relatively unknown, both on local (per wetland) and regional (per landscape) scales. In Sweden, wetland creation has progressed already since the 1990s, and by now larger numbers of created wetlands are present, mainly in the intensively farmed landscapes of southwestern Sweden. This thesis aimed to investigate the following aspects in these systems: (i) their large-scale effects on biodiversity, (ii) their functional diversity of bacterial denitrifiers, (iii) the abiotic and biotic influences on wetland ecosystem functioning, (iv) the potential for biodiversity-function links, and (v) the potential for functional links and joint functioning.(i) Created wetlands hosted diverse assemblages of macroinvertebrates and plants. They maintained a similar com- position and diversity as natural ponds in agricultural landscapes. The environmental conditions per wetland did hardly affect macroinvertebrate and plant assemblages, and the prerequisites for nutrient retention did neither. In landscapes were wetland creation efforts had increased the total density of small water bodies by more than 30%, macroinver- tebrate diversity of created wetlands was facilitated on both local and regional scales. (ii) Diverse communities of denitrifying bacteria with the capacity for conducting different denitrification steps (functional types) were present in all investigated wetlands. The richness of denitrifying bacteria communities was affected by nitrate concentration and hydraulic loading rate, which may potentially be relevant for the nitrogen retention function of created wetlands. The diversity across different functional types of bacterial denitrifiers increased with nitrate concentration. (iii) Both abiotic and biotic factors influenced ecosystem functions of created wetlands. Variation in nitrogen retention was associated to nitrate load, but even to vegetation parameters. In wetlands with constant nitrate load, planted emergent vegetation facilitated nitrogen retention compared to other vegetation types. In wetlands with variable loads, nitrogen retention was facilitated if nitrate load was high and many different vegetation types were present; nitrogen load could explain the majority of the variation in nitrogen retention compared to vegetation parameters. Phosporus retention of created wetlands was best explained by vegetation parameters. Litter decomposition was inhibited at high nitrate to phosphorus ratios. Methane production increased with age and decreased with plant cover. (iv) Biodiversity may facilitate wetland ecosystem functions, particularly in dynamic wetland ecosystems. Nitrogen retention increased with vegetation type diversity, phosphorus retention capacity with plant richness, and litter decomposition with macroinvertebrate diversity. (v) Created wetlands have the capacity of sustaining several parallel ecosystem services. Some wetland functions were coupled; nitrogen retention increased with fast litter decomposition. On the other hand, methane emission and nitro- gen retention were independent of each other, as were nitrogen and phosphorus retention.In conclusion, created wetlands have the potential to at least partly abate the lost biodiversity and multifunctionality caused by the past extensive destruction of natural wetlands in agricultural landscapes. / <p>[Paper II] Milenkovski S., Thiere G., Weisner S.E.B., Berglund O. &amp; Lindgren P.-E. Variation of eubacterial and denitrifying bacterial biofilm communities among constructed wetlands. Submitted manuscript. [Paper V] Thiere G. &amp; Weisner S.E.B. Influence of biotic and abiotic parameters on ecosystem functioning of created wetlands. Manuscript.</p>
247

Development as degradation : aquaculture, mangrove deforestation and entitlements in Batan, Philippines

Kelly, Philip F. (Philip Francis) January 1993 (has links)
This thesis examines pond aquaculture as a development strategy in the Philippines, with particular reference to its impact on the local environment and the livelihoods of local people. / A theoretical framework is provided by recent literature in development studies and human geography, which attempts to move away from an essentialist and ethnocentric development praxis, and towards a locally-based, participatory process of empowerment. From the perspective of such 'alternative' development ideas, orthodox strategies involving modernization, formalization of economic activities, and resource mobilization, can be reassessed. / The promotion of pond aquaculture--and the widespread mangrove deforestation associated with it--is shown to be a strategy endorsed and supported by national and international development agencies. What is often overlooked, however, is the local ecological and economic importance of mangrove ecosystems. This study examines the effects of mangrove removal and fishpond development on the entitlements of people in three coastal communities in the Philippines. Aquacultural development is shown to have detrimental effects on the integrity of the coastal ecosystem and the livelihoods of certain groups of local residents; a rich common property resource is converted into a privately-owned system of cultivation. While benefits accrue to those with access to the capital necessary for the construction of fishponds, the costs of development are borne largely by mangrove gatherers and artisanal fisherfolk, whose share of a diminishing resource base is steadily declining. For these marginal groups, aquaculture is shown to provide few compensating economic benefits. / The study supports, through concrete local evidence, the criticisms made of orthodox approaches to development, and the need to construct attitudes and strategies which are more attuned to local sustainability and equity.
248

Physical and chemical limnological study of an acid mine lake in Sullivan County, Indiana

Broomall, Phillip A. January 1992 (has links)
Southwestern Indiana has numerous lakes developed in abandoned coal mine spoils which support recreational sports fisheries. Some lakes, due to exposure to acid mine drainage from coal wastes and pyritic spoils, are unsuitable habitats for fisheries development. This study examines a publicly owned acid mine lake with an area of approximately 51 ha, following reclamation and elimination of acid producing areas in its drainage basin. Fifteen physico-chemical sample collections were made over a thirteen month period (1991-1992). Parameters sampled included pH, total acidity, iron, manganese, and aluminum. Comparisons were made to historic pre-reclamation water quality data and to established models of acid mine lake recovery. Due to the local topography and exposure to prevailing winds, the lake was generally well mixed throughout the study. Virtually no summer stratification was found, but typical winter season stratification occurred. The water column was well oxygenated throughout the study. Secchi disk transparency varied from 2.5 m to clear to lake bottom (6 m). This study found no significant change in lake water pH (2.9-3.0 to 3.0-3.2 s.u.) since reclamation activities in 1988. However, changes in total acidity and total metal concentrations had occurred since reclamation which suggested that the lake was in early recovery stages. No trends in water quality improvement were determined which could assist in planning toward the eventual establishment of a sports fishery. / Department of Biology
249

Primary Production and Nutrient Dynamics of Urban Ponds

Rolon dos Santos Mérette, Muriel 01 February 2012 (has links)
In urban areas, stormwater management ponds (SWPs) are built to mitigate polluted runoff. Although these ponds are increasing in numbers, their ecology is not well understood. Physical and chemical characteristics of 17 SWPs in the City of Ottawa were measured to determine the drivers of phytoplankton biomass (Chl. a) and primary production (PP). While total phosphorus was the best predictor of algal biomass in the ponds (as in lakes), the imperviousness of the catchment could also predict Chl. a. Planktonic PP in two ponds measured seasonally was more closely related to water residence time than to nutrient concentrations with rates approaching at times the theoretical maximum for aquatic systems. In one pond, whole ecosystem metabolism, estimated using diel changes in dissolved oxygen and δ18O-O2, suggested that these hypereutrophic systems were net sinks for carbon in the summer but likely sources to the atmosphere at other times of the year.
250

Lašišinių bei eršketinių žuvų auginimo analizė UAB „Vasaknos“ žuvininkystės tvenkiniuose / Analysis of raising of the salmon and sturgeon fishes in the ponds of UAB “Vasaknos”

Grigaliūnas, Justinas 19 May 2014 (has links)
Žuvininkystė Lietuvoje turi gilias tradicijas. Tai viena seniausių verslo krypčių, todėl rūpinantis jos plėtra vis didesnis dėmesys telkiamas akvakultūrai, kuri užtikrina įvairių žuvų rūšių išteklių išsaugojimą. Lietuvai tapus ES nare, žuvininkystės plėtros galimybės tapo kur kas didesnės (tą lėmė rinkos laisvė, didelė prekybos erdvė). Žuvininkystei didelis dėmesys buvo telkiamas 2007-2013 m. žuvininkystės sektoriaus programoje. Taip pat svarbu paminėti, kad Lietuvoje įkurtas tarptautinio akvakultūros centro padalinys. Visa tai tik įrodo pakankamą akvakultūros reikšmę Lietuvos versle. Tad šiandien yra labai aktualu analizuoti, kokios yra akvakultūros vystymo galimybės, ekonominė nauda, kokios reikalingos veisimo sąlygos. Atsižvelgiant į tai, šiame darbe didelis dėmesys skiriamas analizuojamo žuvininkystės ūkio UAB „Vasaknos“ žuvų auginimo ypatumams, ekonominių duomenų analizei bei vandens fizinių ir cheminių savybių tyrimams bei jų analizei. Darbo tikslas: išanalizuoti lašišinių ir eršketinių žuvų auginimo ypatumus žuvininkystės ūkyje UAB „Vasaknos“ bei pateikti šio ūkio ekonominių rodiklių ir tvenkinių, saugyklų ir baseino vandens fizinių, cheminių savybių analizę. Darbo uždaviniai: 1) apibrėžti akvakultūros svarbą ir jos perspektyvas Lietuvos žuvininkystėje; 2) išnagrinėti lašišinių bei eršketinių žuvų rūšių ypatybes; 3) išanalizuoti lašišinių bei eršketinių žuvų auginimo ypatumus; 4) išanalizuoti 2010-2012 m. ekonominius rodiklius UAB „Vasaknos“; 5) ištirti UAB „Vasaknos“... [toliau žr. visą tekstą] / Fishery has rich traditions in Lithuania. It is one of the oldest branches of the business, so a growing attention for the aquaculture as for a tool for protecting various kinds of fishes’ resources is being paid at the moment. The possibilities of fishery development have increased significantly after Lithuania has become the member of EU – this is a result of market’s freedom and a bigger space of trading. A big attention for the development of the fishery has been paid in the Programme of the Fishery Sector for 2007-2013. Also it is important to notice that a Department of the International Centre of Aquaculture was established in Lithuania recently by showing the understanding of the importance of aquaculture in the Lithuania’s business field. In respect to this, it is very important today to analyse the possibilities of aquaculture development, its economical benefit as well as the conditions of fishes breeding. So in this Masters’ thesis a big attention is being paid for the peculiarities of fishes raising in the fishery farm UAB “Vasaknos” as well as for analysis of economical data of this farm and for the research of the physical and chemical characteristics of the farm’s ponds’ water. The aim of the thesis: to analyze the peculiarities of the salmon and sturgeon fishes raising in the fishery farm UAB “Vasaknos” as well as provide the analysis of the economical characteristics of this farm’s activity and physical and chemical characteristics of the farm’s ponds’... [to full text]

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