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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.
101

Transformações ambientais das restingas da planície costeira sergipana

Costa, Jailton de Jesus 17 June 2013 (has links)
Man-nature relationship and that one of social groups among themselves, as well as the form of natural resources ownership, are determinant factors of the environment current state and of society life quality. This thesis aimed at analyzing Sergipe coastal plain sandbank landscape environmental changes. The spatial area of this analysis was Sergipe coastal plain, located in nine coastal counties bordering sea, namely: Brejo Grande, Pacatuba, Pirambu, Barra dos Coqueiros, Itaporanga D Ajuda, Estância, Santa Luzia do Itanhy e Indiaroba, grouped into three coast sectors (north, center and south). This study methodology is set upon four stages: documentary fieldwork, laboratory and synthesis. The theoretical-methodological model is the GTP (Geosystem, Territory, Landscape). Bertrand (2007), as this corroborates the idea of having an integral holistic vision, in opposition to the compartmentalized analysis, merely descriptive. Doing environmental research, from a method involving the intrinsic relationship between society and nature, is the innovative challenge of Geography. Among the obtained results, there was a concept that sandbank, in geographical sense, is part of the coastal plain, except for beach, dunes, tômbolos, among other sub-environments, covered or not by vegetation, and especially occupied or not by man, having as internal boundary the coastal plains (Barreiras Group). The study of the landscape physiology allowed one to visualize that landscape transformation by man represents one of the main elements in its formation. It was also possible to apply GTP in the study area. A geosystem (Coastal Plain) with seven territories and two landscape classifications with five major subdivisions was visualized. One reaches the conclusion that Bertrand s model enabled a better understanding of the area, for the integrated analysis, from the socio-environmental perspective that comes from such model, allowed one to see and analyze all spatial area phenomena, enabling a better understanding of Sergipe coastal plain sandbank landscape environmental changes. The presence of Hancornia speciosa Gomes in Sergipe is linked to environmental conditions required by this species, which is found in the study area and also to the reasons expressed in the Refuges Theory from AB Sáber. Currently, sandbanks have been the target of such explosive real estate speculation, which has transformed the natural landscape into a mosaic landscape, meaning, into a disturbed and fragmented landscape, in short term, where the climatic variability produce significant environmental changes when compared to the intensity of human actions. / A relação homem-natureza e dos grupos sociais entre si, bem como a forma de apropriação dos recursos naturais, são fatores determinantes do estado atual do meio ambiente e da qualidade de vida da sociedade. Esta tese objetivou analisar as transformações ambientais da paisagem de restinga da planície costeira sergipana. O recorte espacial desta análise foi a planície costeira sergipana, assentada em nove municípios costeiros defrontantes com o mar, a saber: Brejo Grande, Pacatuba, Pirambu, Barra dos Coqueiros, Aracaju, Itaporanga D Ajuda, Estância, sendo dois estuarinos: Santa Luzia do Itanhy e Indiaroba, agrupados em três setores do litoral (norte, centro e sul). A metodologia deste estudo está configurada em quatro etapas: documental, trabalho de campo, laboratório e síntese. O modelo teórico-metodológico é o GTP (Geossistema, Território, Paisagem) de Bertrand (2007), pois este corrobora com a ideia de se ter uma visão holística integralizada, contrapondo-se à análise compartimentada, meramente descritiva. Fazer pesquisa ambiental, a partir de um método que envolva a intrínseca relação sociedade e natureza, é o desafio inovador da Geografia. Dentre os resultados alcançados, chegou-se a um conceito de restinga que, na acepção geográfica, é a parte da planície costeira, com exceção da praia, dunas, tômbolos, entre outros sub-ambientes, coberta ou não por vegetação e, principalmente, ocupada ou não pelo homem, tendo como limite interno os tabuleiros costeiros (Grupo Barreiras). O estudo da fisiologia da paisagem permitiu visualizar que a transformação da paisagem pelo homem representa um dos elementos principais na sua formação. Foi possível também aplicar o GTP na área de estudo. Visualizou-se um Geossistema (Planície Costeira), sete territórios e duas classificações de paisagem com quatro subdivisões principais. Conclui-se que o modelo de Bertrand possibilitou um maior entendimento da área, pois a análise integrada, a partir da perspectiva socioambiental que dele se extrai, permitiu enxergar e analisar a maioria dos fenômenos do recorte espacial, possibilitando compreender melhor a realidade das transformações das restingas da planície costeira sergipana. A presença da Hancornia speciosa Gomes em Sergipe está ligada às condições edafoclimáticas exigidas por essa espécie, a qual é encontrada na área de estudo e também aos motivos expressos na Teoria dos Refúgios de AB Sáber. Atualmente, as restingas têm sido alvo de uma explosiva especulação imobiliária, que tem transformado o ambiente natural numa paisagem de mosaicos, ou seja, numa paisagem antropizada e fragmentada, onde a variabilidade climática produz alterações ambientais significativas quando comparada com a intensidade das ações humanas.
102

Study and application of the Inherent Optical Properties of coastal waters from the Phaeocystis-dominated Sounthern Bight of the North Sea

Astoreca, Rosa 14 June 2007 (has links)
The Belgian Coastal Zone (BCZ) in the Southern Bight of the North Sea is a highly dynamic and optically complex area. This is due to high non-algal particles (NAP) and coloured dissolved organic matter (CDOM) content which in spring adds together with undesirable blooms of the haptophyte Phaeocystis globosa. There is a need for improving the algorithms for chlorophyll a (chl a) retrieval in these highly turbid waters and for developing algorithms for species detection in order to attempt to create an early warning bloom system. This information will contribute to the knowledge of the extent and magnitude of the P. globosa bloom in Belgian waters. In this study, pure cultures of the main taxa present in the BCZ, diatoms and P. globosa, were combined with field measurements of light absorption of total particles, phytoplankton and dissolved material, pigment determination and phytoplankton counts to address the main objectives. Sampling was performed during 8 cruises covering winter, spring, summer and late summer, and along nearshore-offshore gradients from 2003 to 2006. <p>The area is characterised by a high spatio-temporal variability of IOPs due to the high dynamics of the area in terms of currents, salinity gradients and biological production. During spring the presence of P. globosa modulates the IOPs across all the area, the particle absorption is significantly higher than summer and there is no significant coast-offshore variability for phytoplankton and CDOM. <p>The design of chl a retrieval algorithms assumes negligible absorption of NAP and CDOM in the near infrared (NIR) and the use of a fixed value of specific phytoplankton absorption. It is shown that neglecting the NAP and CDOM absorption in the NIR will have a significant overestimation impact in retrieval of chl a. On the other hand, the specific phytoplankton absorption was found to be highly variable (0.015 „b 0.011 m2 mg chl a-1). Both results will affect directly the retrieved chl a. The spatial variability of CDOM was significant varying between 0.20-1.31 m-1 in the marine area and between 1.81-4.29 m-1 in the Scheldt estuary. CDOM was found to be related to salinity with conservative mixing within the Scheldt estuary and during some seasons in the BCZ, however deviations from conservative mixing suggest other inputs to the CDOM pool. Analyses of the spectral slope of the CDOM absorption curve revealed two main CDOM pools in the area, an allochthonous one delivered by the Scheldt estuary and an autochthonous one associated with the phytoplankton spring bloom decomposition. Algorithms for CDOM retrieval will be affected if the variability in the relation between CDOM and salinity is not taken into account. <p>The optical characterisation of diatoms and P. globosa from the BCZ in pure cultures revealed that the main differences in the phytoplankton absorption spectra were found at 467 and 500 nm corresponding to the absorption of the pigments chlorophyll c3 (chl c3) characteristic of P. globosa and fucoxanthin, respectively. Accordingly, both the absorption at 467 nm and the ratio 500/467 nm were successfully used to discriminate the two taxa in cultures and field samples. This latter indicator was not preserved in the reflectance signal due to degradation of the signal when passing from absorption to reflectance, and thus could not be used for algorithm development. The spectral feature at 467 nm was later used as the basis for the development of a flag-type algorithm to detect chl c3 using either absorption or water-leaving reflectance data. Also, the correlation between the algorithm¡¦s retrieved chl c3 and P. globosa cell number allowed the quantification of the bloom. The main findings of this thesis highlight the importance of the IOPs characterisation for the improvement and development of ocean colour retrieval algorithms in these highly complex waters.<p> / Doctorat en Sciences / info:eu-repo/semantics/nonPublished

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