7 resultados para Rio Iguaçu
em Repositório Institucional UNESP - Universidade Estadual Paulista "Julio de Mesquita Filho"
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
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The freshwater phytoplankton, responsible for a significant part of primary production in rivers and lakes, is of great importance for matter and energy available to other trophic levels of structuring aquatic food chains. In recent decades, the construction of dams, especially for the generation of electricity, produced changes not only in physical and chemical characteristics of rivers, but also in biocoenosis of these ecosystems. Thus, research is needed to expand the basic knowledge about these environments and subsidize actions appropriate conservation and management. Considering that lotic environments are relatively little studied, and the river-reservoir interaction, the work aims to analyze the limnological conditions and assemblies phytoplankton along the gradient established by the Itaipu reservoir and downstream stretch of the Paraná River. During two periods of the year, winter and summer, we analyzed nine sampling stations: one in lentic environment (the dam), six on the Parana River (each 5 km), at the mouth of a river Monday and another at the mouth of the Iguazu river. The phytoplankton community was composed of 315 taxa, with the class Bacillariophyceae most specious. At every point the richness was higher in summer and with a longitudinal trend in the increasing points after falling after the dam and the contribution of the tributaries. The number of taxa common to the three rivers was low in both study periods. The higher taxa can be explained by the variety of environments sampled, different residence times of water and nutrient concentrations, whereas the rivers Iguazu and Monday suffer high human influence. The greater abundance of organisms in the dam, in both periods, it should be the class Cryptophyceae contributing over 75% of total phytoplankton in point. In cluster analysis (composition and abundance)...(Complete abstract click electronic access below)
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Pós-graduação em Ciências Biológicas (Zoologia) - IBB
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The analysis of natural processes, such as landslides, has a great importance for the prevention of accidents in pipelines, since it might compromise its security, with serious social and environmental implications. Considering the large territorial dimensions that pipelines can reach, remote sensing tools have great applicability for data acquisition, allowing the analysis of large areas in regular time periods. This study aims to analyze the relations between the occurrence of landslides and its natural conditionings, on a stretch of the ORBEL pipeline, in the municipalities of Duque de Caxias, Nova Iguaçu and Belford Roxo – Rio de Janeiro. GeoEye sensor system images were used with spatial resolution of 0.5 m, from November/2009, January/2010 and March/2010, that are months of summer rains. The work involved the characterization of the study area and existing landslides, through bibliographic data collection; the application of visual analysis techniques for the extraction of landslide scars and fractures; preparation of maps for the landslide constraints and preparation of the susceptibility map. In the images from November only three landslide scars were extracted, while in January there were 166 and 111 in March. Difficulties were found with the shading in the images. From the relations among landslide scars, lithological units, relief systems, slope, downhill profile and the generated map of landslide susceptibility, presented in 1:70,000 scale, it was possible to conclude that slope is the main determinant of the process, allied secondarily to downhill profile, relief systems and lithology
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Pós-graduação em Geociências e Meio Ambiente - IGCE