998 resultados para Sapais - Estuários - Rio Tejo (Portugal) - Caracterização geoambiental


Relevância:

40.00% 40.00%

Publicador:

Resumo:

The aim of this study was the seasonal characterization of the morphology, sedimentology and hydrodynamic of the Açu, Cavalos and Conchas estuaries. These estuaries are inserted in a semi-arid climate area and form the mouth of the hydrographic basin of the Piranhas-Açu river, that represent the discharge of the largest watershed in the state. They are embedded in an environment consisting of a fluvial-marine floodplain, mangrove ecosystem, sandbanks, fields of dunes, spits and sandy beaches. Adjacent to the natural units are the main local socioeconomic activities (oil industry, salt industry, shrimp farming, fishing and tourism) are dependent on this river and its conservation. The environmental monitoring is necessary because it is an area under constant action of coastal processes and at high risk of oil spill. The acquisition and interpretation of hydrodynamic, sonographic and sediment data was conducted in two campaigns, dry season (2010) and rainy season (2011), using respectively the current profiler ADCP Doppler effect, the side-scan sonar and Van Veen sampler. In these estuaries: Açu, Cavalos and Conchas were identified the following types of bedforms: flatbed and Dunes 2-D and 3-D (small to medium size), generated at lower flow regime (Froude number <1). Structures such as ripples were observed in the Açu estuary mouth. The higher values of flow discharge and velocity were recorded in the Açu estuary (434,992 m³.s-¹ and 0,554 m.s-¹). In rainy season, despite the record of highest values of discharge and flow velocities at the mouth, the energy rates upstream did not differ much from the data of the dry season. However, in all estuaries were recorded an increase in speed and flow, with reservation to the flow in the Açu estuary and flow at the mouth of the Conchas estuary. Sediment grain sizes tend to increase towards the mouth of the estuary and these ranged from very fine sand to very coarse sand, medium sand fraction being the most recurrent. Based on the data acquired and analyzed, the estuaries Açu, Cavalos and Conchas are classified as mixed , dominated by waves and tides. According to their morphology, they are classified as estuaries constructed by bar and according to the classification by salinity, estuaries Conchas and Cavalos were ranked as hypersaline estuaries, and Açu as hypersaline and vertically well mixed type C

Relevância:

40.00% 40.00%

Publicador:

Resumo:

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior

Relevância:

40.00% 40.00%

Publicador:

Resumo:

This work presents geophysical and geological results obtained in a dunefield located in the east coast of Rio Grande do Norte State, with the aim to recognize the aeolian body depositional geometries to a future geologic modeling of the aeolian petroliferous reservoirs. The research, which was done in blowouts region situated at Nisia Floresta Municipally, included the characterization of external geometries with GPS and internal geometry analysis by GPR. Data was integrated in GoCAD software, where it was possible the three-dimensional characterization and interpretation of the studied deposits. The interpretation of GPR profiling allowed identifying: First-order bounding surfaces that separated the aeolian deposits of the Barreiras Formation rocks; Second-order bounding surfaces, which limit dune generations and Third-order bounding surfaces, a reactivation surface. This classification was based and adapted by the Brookfield (1977) and Kocurek (1996) propose. Four radarfacies was recognized: Radarfacies 1, progradational reflectors correlated to foresets of the dunes, Radarfacies 2, plain parallels reflectors related to sand sheets, Radarfacies 3, plain parallels reflectors associated to reworking of the blowout dune crest and Radarfacies 4, mounded reflectors associated to vegetated mound of sand or objects buried in subsurface. The GPR and GPS methods was also employed to the monitoring of dunefields susceptible to human activities in Buzios Beach, where the constructions along the blowout region and the tourism are changing the natural evolution of the deposits. This fact possibly to cause negative impacts to the coastal zone. Data obtained in Dunas Park, a unit environmental conservation, was compared with information of the Buzios Beach. There is a major tendency of erosion in Buzios, specifically in blowout corridor and blowout dune

Relevância:

40.00% 40.00%

Publicador:

Resumo:

The brazilian marginal basins have a huge potential to generate and accumulate petroleum. Incised valleys which are eroded in response to a fall of relative sea level are related to potential reservoir as well, modern drowned-valley estuaries serve as harbors to petroleum and salt industries, fisheries, waste-disposal sites and recreational areas for a significant fraction of the world s population. The combined influence of these factors has produced a dramatic increase in research on modern and ancient incised-valley systems. This research is one expression of this interest. The integrated use of satellites images and high resolution seismic (bathymetry, sides scan sonar) was used on the Apodi River mouth-RN to characterizes the continental shelf This area is located at the Potiguar Basin in the NE Brazilian Equatorial Atlantic margin. Through bathymetric and side scan sonar data processing, a digital Terrain Model was developed, and a detailed geomorphologic analysis was performed. In this way was possible to recognize the geomorphologic framework and differents sismofacies, which may influence this area. A channel extending from the ApodiMossoró river mouth to the shelf edge dominates the investigated area. This structure can be correlated with the former river valley developed during the late Pleistocene sea level fall. This channel has two main directions (NW-SE and NE-SW) probably controlled by the Potiguar Basin structures. The western margin of the channel is relatively steep and pronounced whereas the eastern margin consists only of a gentle slope. Longitudinal bedforms and massive ridges also occur. The first are formed doe to the shelf sediment rework and the reef-like structures probably are relics of submerged beachrock-lines indicating past shoreline positions during the deglacial sea-level rise. The sub-bottom seismic data allow the identification of different sismic patterns and a marcant discontinuity, interpreted as the Upper

Relevância:

40.00% 40.00%

Publicador:

Resumo:

The geo-environmental zoning is an important means to plan the management of the territory, once it is the result of integration of different elements of the physical environment. The Municipality of Crato has a diversity of geo-environmental systems due to its complex landscape, which characterization and delimitation will contribute to the most appropriate occupation and the fewer prejudicial to municipal area. This study, which was supported by geo-systemic theory, searched to reach the following objectives: to elaborate a proposal of geo-environmental zoning; to characterize identified and demarcated geo-environmental systems, including their potentiality and limitations of land use and human occupation; and to generate a database on digital maps through GIS Geographic Information System. Four geo-environmental systems were identified (Chapada do Araripe: plateau and hillside, Massif and residual crest, Sertão of peripheric southern depression and fluvial Plains) and ten geo-environmental subsystems (Eastern plateau covered by cerradão/cerrado, Western plateau covered by cerrado/carrasco, Northern-west hillside, central residual Massif, Northern Residual Massifs, Sertaneja depression dominated by sedimentary materials, Sertaneja depression dominated by embasement crystalline material; wet fluvial plains and dry fluvial plains). The identified system and subsystem are similar to those proposed by FUNCEME in spite of some changes due to the more detailed mapping

Relevância:

40.00% 40.00%

Publicador:

Resumo:

Issues concerning coastal regions, especially the beaches have sparked quite complex because studies are there that most people in the world has secured housing, mainly from the half of the last century, without concern for the natural dynamics of these environments, which have complex interactions of continental and oceanic, coastal responsible for changes in locations that can be perceived in a few years and sometimes even a few days or hours. The search took as main goal, analyze the Genipabu Beach, in the municipality of Extremoz/RN, fragile environment and rapid momentum, which has been occupied in a disorderly and unplanned. Carried out a beach monitoring through profiles beach environments: defined stages morphodynamics; realization of characterize hydrodynamic processes; identification of changes in the landscape. To this end, made necessary a survey from the bibliographic collection for theoretical and conceptual rationale. An empirical step for conducting the environmental characterization of hydrodynamics, leveling and topographic analysis of sediments (in laboratory), for observation of changes in features, influenced, and natural dynamics, anthropic action that increasingly comes taking the characteristics from the natural landscape. Underlines therefore the importance of academic studies in several areas in these environments, for setting up a coastal zoning giving public subsidies for managers for managing and planning the use and occupation of the coast in their areas

Relevância:

40.00% 40.00%

Publicador:

Resumo:

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Relevância:

40.00% 40.00%

Publicador:

Resumo:

As alterações que envolvem as globinas devem-se a modificações em genes responsáveis pela seqüência e estrutura das cadeias polipeptídicas, bem como aos genes reguladores da síntese destas cadeias. Hemoglobinas variantes apresentam estrutura química diferente da hemoglobina normal correspondente, resultante de mutações em uma ou mais bases nitrogenadas, ocasionando a troca de aminoácidos nas globinas alfa, beta, delta ou gama. A hemoglobina N-Baltimore é uma variante de globina beta, com substituição da lisina, na posição 95, por ácido glutâmico, apresentando mobilidade eletroforética mais rápida que a hemoglobina A em pH alcalino. Nas análises eletroforéticas em pH alcalino realizadas em doadores de sangue do Hemocentro de São José do Rio Preto (SP) identificamos a presença de portador de hemoglobina rápida em heterozigose, posteriormente confirmada por focalização isoelétrica e cromatografia líquida de alta pressão (HPLC). Os estudos de hemoglobinas anormais em doadores de sangue permitem a identificação de variantes raras e possibilitam o aconselhamento genético adequado a cada caso com estudo familial.

Relevância:

40.00% 40.00%

Publicador:

Resumo:

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Relevância:

40.00% 40.00%

Publicador:

Resumo:

O objetivo desta pesquisa foi caracterizar os elementos físicos da bacia do córrego Santo Antônio, buscando compreender a influência que a área de entorno dessa bacia exerce sobre a Floresta Estadual Edmundo Navarro de Andrade (FEENA). Para isto, foram elaboradas as cartas geomorfológica e de uso do solo, além da compilação de dados geológicos, pedológicos e climáticos. Essa influência foi avaliada em termos da dinâmica de remobilização de materiais provenientes das nascentes, que não pertencem a FEENA, e que se constituem, portanto, em área de uso agrícola. A análise das características físicas indicou que essa área é susceptível a ação dos processos morfogenéticos e que estes foram intensificados e acelerados pelo uso do solo ao redor das nascentes. Verifica-se, assim, a necessidade de se reavaliar esse uso e de se fiscalizar o cumprimento da própria legislação ambiental, no que se refere ao uso e ocupação do território, em fundos de vale.

Relevância:

40.00% 40.00%

Publicador:

Resumo:

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Relevância:

40.00% 40.00%

Publicador:

Resumo:

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Relevância:

40.00% 40.00%

Publicador:

Resumo:

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Relevância:

40.00% 40.00%

Publicador:

Resumo:

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)