• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 11
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • Tagged with
  • 17
  • 17
  • 7
  • 4
  • 4
  • 4
  • 3
  • 3
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • 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.
11

Mangroves, shrimp aquaculture and coastal livelihoods in the Estero Real, Gulf of Fonseca, Nicaragua /

Benessaiah, Karina. January 1900 (has links)
Thesis (M.Sc.). / Written for the Dept. of Geography. Includes bibliographical references.
12

The dynamics of mangrove forests in relation to die-back and human use in Bunaken National Park, North Sulawesi, Indonesia /

Djamaluddin, Rignolda. Unknown Date (has links) (PDF)
Thesis (Ph.D.) - University of Queensland, 2004. / Includes bibliography.
13

Prospecção e análise funcional de enzimas provenientes de microbiota de manguezais do Estado de São Paulo / Prospecting and functional analysis of enzymes from microorganisms in mangroves of São Paulo State

Ottoni, Júlia Ronzella, 1980- 27 August 2018 (has links)
Orientadores: Valéria Maia Merzel, Anete Pereira de Souza / Tese (doutorado) - Universidade Estadual de Campinas, Instituto de Biologia / Made available in DSpace on 2018-08-27T08:16:52Z (GMT). No. of bitstreams: 1 Ottoni_JuliaRonzella_D.pdf: 14116261 bytes, checksum: f49982ceaff5d9b1dd9c87dcf8c01fcf (MD5) Previous issue date: 2015 / Resumo: Os manguezais são ecossistemas peculiares de alta atividade biológica, considerados um dos ambientes mais ricos do mundo. No Brasil, os manguezais ainda são pouco estudados, tornando o conhecimento e exploração de micro-organismos e seus metabólitos nesses ecossistemas um tópico importante. Os manguezais são ambientes adversos, caracterizados, em muitos casos, pela alta salinidade, variações constantes de pH e temperatura, e condições anóxicas. Micro-organismos adaptados à essas condições podem ser fontes de moléculas bioativas ainda desconhecidas e de interesse ambiental e econômico. Neste contexto, o presente trabalho teve como um dos objetivos analisar a diversidade taxonômica e funcional presente em sedimento de manguezal contaminado com petróleo através do sequenciamento de uma biblioteca metagenômica construída em vetor do tipo fosmídio. As análises taxonômicas da biblioteca metagenômica mostraram predominância do filo Proteobacteria, seguido por Actinobacteria, Planctomycetes, Firmicutes, Cloroflexi e Bacteroidetes. Em nível de classe, a mais abundante foi Gamaproteobacteria, seguida de Alfaproteobacteria e Deltaproteobacteria. A diversidade taxonômica se reflete na diversidade metabólica, com espécies capazes de degradar hidrocarbonetos, oxidar enxofre em zonas de transição oxica-anóxica costeiras, transformar metais pesados e outros compostos xenobióticos, dentre outras habilidades. Em adição, foram realizadas triagens funcionais com 4.800 clones da biblioteca e 215 isolados bacterianos para esterase e lipase, 5.184 clones para atividade proteolítica e os genomas de duas bactérias foram analisados in silico na busca de genes que codificam para atividade de catalase. As triagens dos clones resultaram em 17 hits positivos para esterases que posteriormente se revelaram falsos-positivos, e 182 hits positivos para proteases nos ensaios com sondas, sendo 60 hits positivos no pH 4,0, 55 no pH 7,0 e 67 no pH 9,0. Nos ensaios com isolados de bactérias foram detectados 42 com atividade de esterase e 20 com atividade de lipase, sendo que a melhor atividade de esterase foi obtida com um isolado de Gordonia sp. e a melhor atividade de lipase foi obtida para um isolado de Bacillus safensis. Estes dois isolados já possuem seus genomas sequenciados e uma análise in silico foi realizada para busca dos respectivos genes de atividade lipolítica. Na busca in silico por catalases foi selecionada uma sequência completa para ensaios de expressão. Foram desenhados pares de primers para amplificação dos genes das três enzimas e, destes, os genes da lipase e da catalase foram expressos, ambos do Bacillus safensis. A caracterização funcional e estrutural foi realizada com a catalase, cujo gene possui 1500 pb, é um tetrâmero composto por 4 monômeros de 59 kDa cada, ativa em intervalo de pH de 6,0 a 12 e temperaturas de 25 ºC a 55 ºC, com atividade ótima em pH 10 e 30 ºC e estável até 40 ºC. Os resultados mostraram que o mangue impactado é composto por populações microbianas adaptadas ao ambiente, e também responsáveis pela degradação de compostos xenobióticos, auxiliando na sua recuperação. A abordagem metagenômica foi bem sucedida nas triagens funcionais para proteases, indicando um grande potencial proteolítico no ambiente. As triagens funcionais com os isolados mostraram a presença de enzimas lipolíticas ativas, e a catalase expressa exibiu características funcionais interessantes, tais como atividade ótima em pH 10 e estabilidade térmica até 40 ºC, com potencial aplicação industrial / Abstract: Mangroves are unique ecosystems of high biological activity and are considered one of the richest environments in the world. In Brazil, mangroves are still poorly studied, making the knowledge of microorganisms and their metabolites in these ecosystems an important topic. Mangroves are harsh environments characterized, in many cases, by high salinity, high pH and temperature variations, and anoxic conditions. Microorganisms adapted to these conditions may be sources of yet unknown bioactive molecules of environmental and economic interest. In this context, one of the objectives of the present study was to analyze the taxonomic and functional diversity present in mangrove sediment contaminated with oil through the sequencing of a metagenomic library constructed using fosmid vector. The taxonomic analysis of the metagenomic library showed predominance of Proteobacteria phylum, followed by Actinobacteria, Planctomycetes, Firmicutes, Chloroflexi and Bacteroidetes. At class level, the most abundant was Gammaproteobacteria, followed by Alphaproteobacteria and Deltaproteobacteria. The taxonomic diversity is reflected in the metabolic diversity, with species capable of degrading hydrocarbons, oxidizing sulfur in oxic-anoxic coastal transition zones, transforming heavy metals and other xenobiotic compounds, among other skills. In addition, functional screenings were performed with 4,800 fosmid clones and 215 bacterial isolates for esterases and lipases, and with 5,184 clones for proteolytic activity and the genomes of two bacteria were analyzed in silico to search for genes encoding catalase activity. The screening of the clones resulted in 17 positive hits for esterases that later proved to be false-positive, and 182 positive hits for proteases using probe-based assays: 60 positive hits at pH 4.0, 55 at pH 7.0 and 67 at pH 9.0. Tests with bacterial isolates yielded 42 positive hits for esterase activity and 20 for lipase activity. The best esterase activity was obtained with one isolate of Gordonia sp. and the best lipase activity was obtained with one isolate of Bacillus safensis. These two isolates have their genomes already sequenced and in silico analyses were performed in the search for the respective genes of lipolytic activity. In silico analysis for catalase genes was performed and a complete sequence was selected for expression assays. Primer pairs were designed to amplify the genes encoding the three enzymes, and of these, lipase and catalase were expressed, both from Bacillus safensis. The functional and structural characterization was carried out with catalase, which gene has 1500 bp, it is a tetramer composed of four monomers of 59 kDa each, active in the pH range from 6.0 to 12 and temperatures of 25 °C to 55 °C, with optimum activity at pH 10 and 30 °C and stable until 40 ºC. The results showed that oil-impacted mangrove is composed by microbial populations adapted to the environment, responsible for the degradation of xenobiotics and assisting in the recovery of the mangrove. The metagenomics approach was successful in the functional screening for proteases, indicating a great proteolytic potential in the environment. Functional screening with the bacterial isolates showed presence of active lipolytic enzymes, and the expressed catalase exhibited unique functional characteristics, such as optimal activity at pH 10 and thermal stability until 40 ºC, with potential industrial application / Doutorado / Genetica de Microorganismos / Doutora em Genética e Biologia Molecular
14

Macrofauna associada à comunidade Bostrychietum em diferentes ambientes no litoral norte de São Paulo / Macrofauna associated with Bostrychietum community in different environments on the northern coast of São Paulo

Garcia, Abel Furlan, 1984- 23 August 2018 (has links)
Orientador: Fosca Pedini Pereira Leite / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Biologia / Made available in DSpace on 2018-08-23T22:36:54Z (GMT). No. of bitstreams: 1 Garcia_AbelFurlan_M.pdf: 2175839 bytes, checksum: 3883ef33f2fc268ad9117685b3795634 (MD5) Previous issue date: 2013 / Resumo: As algas do gênero Bostrychia, juntamente com outras algas, formam uma comunidade que está presente nos costões, bem como associadas com pneumatóforos nos manguezais. Sua estrutura complexa propicia a retenção de sedimento, água e matéria orgânica, bem como um mosaico de algas que varia temporalmente e, formando microhabitats que são refúgios para a fauna. O objetivo deste estudo é analisar a distribuição da fauna associada à comunidade de algas Bostrychietum e os fatores que influenciam a sua distribuição. Foram amostrados dois costões rochosos e uma área de manguezal no litoral norte do Estado de São Paulo. Nestes locais, foram realizadas quatro coletas durante o ano de 2012, sendo obtidas amostras para a identificação da fauna associada e para a análise de fatores ambientais (teor de matéria orgânica e granulometria do sedimento). O peso da amostra (peso seco da alga + do sedimento) foi usado para o cálculo da densidade de indivíduos. A composição das algas variou nos meses amostrados em todos os locais. Amostras do mesolitoral apresentaram mais espécies de algas associadas que as do supralitoral. Tal fato influenciou a distribuição da macrofauna, uma vez que a diversidade diminuiu nas amostras com menos espécies de algas. Os moluscos e anfípodes onívoros foram abundantes em todas as amostras, sendo os anfípodes Hyalidae dominantes. A interação entre as variações sazonais das algas da comunidade e o hidrodinamismo modula a distribuição da macrofauna nos costões. No manguezal, os pneumatóforos mais próximos da água apresentaram diferenças com relação às amostras do interior do mangue quanto à composição de algas e da fauna associada. O Bostrychietum é, portanto um microecossistema com vários fatores modulando as interações entre as espécies, sendo necessárias maiores investigações das relações existentes entre as espécies e os fatores ambientais atuantes / Abstract: The algae of the genus Bostrychia together with other algae form a community present in rocky shores as well as associated to pneumatophoresin mangroves. Both their complex structure with ramifications which provide sediment, water and organic matter retention and the algae mosaic that varies seasonally foster microhabitats which are refuges for the fauna during low tide periods. The aim of this study was to evaluate the distribution of fauna associated wih algal community Bostrychietum and the factors that influence their distribution.Two rocky shores and one mangrove area in the Northern shore of São Paulo State were sampled. In these sites four samplings were made during the year of 2012: samples were collected for the identification of the associated fauna and for the analysis of environmental factors (organic matter content and sediment grain size). The weight of the sample (alga dry weight + sediment dry weight) was used to calculate the density of individuals. The algal composition varied through the sampled months as well as in relation to distance from the sea. Samples located in the mesolittotal presented more algal species associated. Such fact influenced macrofauna distribution since diversity was lower for samples containing less algal species. Omnivore mollusks and amphipods were abundant in all samples, Hyalidae amphipods being dominant.The interaction between seasonal variations of the algae in the community and the hydrodynamics modulates the distribution of macrofauna on the rocky shores. In the mangroves, those pneumatophores closer to the water presented diferences in relation to the composition of algae and associated fauna compared to samples from inner parts of the mangrove. Thus, Bostrychietum is a microecosystem with many factors modulating the interactions between species, making further investigation on the existing relationships between species and the operating environmental factors necessary / Mestrado / Ecologia / Mestre em Ecologia
15

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.
16

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

Kelly, Philip F. (Philip Francis) January 1993 (has links)
No description available.
17

Impact of anthropogenic activities on the vegetation structure of mangrove forests in Kribi, the Nyong river mouth and Cameroon estuary / Impacts des activités anthropiques sur la structure de la végétation des mangroves de Kribi, de l'embouchure du fleuve Nyong et de l'estuaire du Cameroun

Nfotabong Atheull, Adolphe 13 September 2011 (has links)
Mangroves are intertidal ecosystems found along the tropical and subtropical coastlines.<p>Though globally recognised as ecosystems of ecological, biological and economical<p>remarkable importance, these ecotone formations are characterised by a continuously<p>increasing anthropization. However, very little studies have been focused on the impact of<p>various anthropogenic activities on the mangrove vegetation structure.<p>We have firstly (a) assessed the commercial and subsistence utilization of mangrove<p>wood products in the Littoral region (Cameroon estuary). Then, we have confronted the<p>subsistence usages of mangrove wood products in the Southern region (close to the mouth of<p>the Nyong River and Mpalla village (Kribi)) in comparison with the Littoral region. By doing,<p>we have compared the local residents‟ perceptions on environmental changes that occurred<p>within the two regional mangrove forests. Also, we have (c) studied the structural dynamic of<p>mangrove vegetation neighbouring the Douala city (Cameroon). Always in the vicinity of this<p>town, we have (d) reconstructed the original structure of largely disturbed mangrove forests.<p>Moreover, we have (e) map the mangrove structure in a non peri-urban setting located within<p>the Cameroon estuary. Here, we have finally (f) analysed the spatial distribution of a black<p>mangrove namely Avicennia germinans (L.) Stearn.<p>Our results underlined an excessive utilization of mangrove wood products in the<p>Cameroon estuary. We have showed that the frequency of mangrove harvesting was relatively<p>fewer in Kribi (Mpalla) and the mouth of the Nyong River. The local people inhabiting these<p>two localities perceived mangroves as less degraded areas. In contrast, those established<p>within the Cameroon estuary stated that mangroves were largely disturbed. When combining<p>the local people statements with our field observations, we recorded that it a complex mix of<p>causes (e.i. clear-felled corridors, agriculture, sand and gravel extraction, over-harvesting and<p>anarchic urbanization) that have led to the largely degradation (vegetation and sediment) of<p>the peri-urban mangroves in Cameroon. A diachronic analysis (1974, 2003, 2009) of their<p>coverage revealed that over the 35-year period, mangrove had decreases in cover of 53.16%<p>around Douala. We have also showed that in the peri-urban settings, wood harvesting was<p>commonly applied on the structurally more complex (highly dense stands neighbouring the<p>habitations) mangrove forests (Mboussa Essengue) and, in a lesser extent, on the structurally<p>more developed mangrove stands (fewer dense stands faraway from Douala). On the other<p>hand, the mapping analysis of the non peri-urban mangroves (distant from Douala) has<p>revealed that the structure of these intertidal forests was relatively less impacted. In the<p>Cameroon estuary, we also showed that A. germinans trees were randomly distributed on<p>almost one-half of the sampling plots and clumped at some scales on the remaining plots.<p>Accordingly, this species might play a significant role in the recovery process of artificial<p>gaps found in the non peri-urban areas.<p>The multi-disciplinary approach employed in this study has allowed a better<p>understanding of the direct and indirect impacts of anthropogenic activities on the mangrove<p>vegetation structure in Cameroon. These results constitute a fundamental data base quite<p>useful for the multi-temporal monitoring of these littoral ecosystems perpetually disturbed.<p>The application of similar approach in other mangroves facing high anthropogenic pressures<p>appears important. / Doctorat en Sciences / info:eu-repo/semantics/nonPublished

Page generated in 0.5765 seconds