1000 resultados para Estrutura temporal


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Pós-graduação em Aquicultura - FCAV

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The climate is one of the main elements of the natural environment that governs the life of man. Specific conditions of temperature, humidity, light, wind and precipitation have direct influence on physiological conditions that man needs to survive and more than that, besides the influence on human and animal physiology, the climatic elements are also responsible for a significant portion of economic activities such as industry, agriculture, commerce, transportation, and others. Therefore, any change in weather patterns has great impact on daily activities, and even more in urban sites, where the most of population is concentrated nowadays. Based on this discussion and concerned in understand the atmospheric structure, this monograph intends to analyze the pattern of atmospheric and temperature element in seven cities of small and medium size located in the state of São Paulo countryside... (Complete abstract click electronic access below)

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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Pós-graduação em Agronomia (Genética e Melhoramento de Plantas) - FCAV

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

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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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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The artifi cial eutrophication is one of the biggest t h reat for the quality of aquatic ecosystems in the whole world. The expectations for the future climatic scenarios in arid and semi - arid regions are intense and frequent droughts enhancing the risk of eutrophicati on and cyanobacterial blooms. Restoration techniques of eutrophic lakes were proposed to reduce nutrient loading and improve the water quality. A successful technique used in temperate regions is the biomanipulation by benthivorous fish removal . Our hypoth esis is that the benthivorous fish removal reduces phytoplankton total biomass and change the composition of phytoplankton functional groups, improving water quality. The aim of the study was evaluate the impact of biomanipulation on phytoplankton function al groups and in the water quality. We applied the technique of biomanipulation in the artificial lake ESEC, in a semi - arid region of Brazil and analyzed the physical and chemical variables and the dynamic of phytoplankton functional groups monthly during November 2012 to August 2013. With the removal of benthivorous fish we observed a significant increase of the euphotic depth, phytoplankton richness and the recruitment of green algae (groups F and J ), indicators of good water quality. However, we did not observe significant differences on total phosphorous concentration and on phytoplankton biomass and diversity. The drought effect in the region during the study was evident , promoting a drastic reduction on water level which influenced the availability of resource and affected phytoplankton community before the biomanipulation. To evaluate the effect of severe drought on the dynamic of phytoplankton functional groups and test if the drought periods are favorable to dominance of cyanobacterial groups, we stu died two artificial neighbors lakes (ESEC and Pocinhos) in a semi - arid tropical region during May 2012 to February 2013. We observed a temporal differentiation of biotic and abiotic variables caused by drought. Both lakes presented reduction of 2 meters of water level and increase on conductivity, turbidity, nutrients concentration and a reduction on water transparency, during the severe drought. The deeper lake (Pocinhos) increased phytoplankton total biomass and presented cyanobacterial functional group d ominance (group S N ) and the shallower lake (ESEC) reduced phytoplankton total biomass and presented dominance of mixotrophic and flagellate functional groups (groups W 1 e W 2 ). Summarizing, the knowledge of the effects of benthivorous fish removal in semi - a rid tropical lakes still unknown and this study had limitations caused by the impact of drought. Thus, it is necessary a long term monitoring to investigate the real effects of biomanipulation on the functioning of the studied ecosystems. Otherwise, period s of drought could have opposite effects (increase or reduction) on total biomass and composition of phytoplankton functional groups. Drought not always leads to dominance of cyanobacterial groups.

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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Spatial-temporal dynamics of zooplankton in the Caravelas river estuary (Bahia, Brazil). The survey was conducted in order to describe the zooplankton community of the estuary Caravelas (Bahia, Brazil), to quantify and relate the patterns of horizontal and vertical transport with the type of tide (neap and spring) and tidal phase (flood and ebb). Zooplankton samples were collected with the aid of a suction pump (300L), filtered in plankton nets (300μm) and fixed in saline formalin 4%. Samples were collected at a fixed point (A1), near the mouth of the estuary, with samples taken at neap tides and spring tides during the dry and rainy seasons. Samples were collected for 13 hours, at intervals of 1 hour in 3 depths: surface, middle and bottom. Simultaneous collection of biological, we measured the current velocity, temperature and salinity of the water through CTD. In the laboratory, samples were selected for analysis in estereomicroscope, with 25 groups identified, with Copepoda getting the highest number of species. The 168 samples obtained from temporal samples were subsampled and processed on equipment ZooScan, with the aid of software ZooProcess at the end were generated 458.997 vingnettes. 8 taxa were identified automatically, with 16 classified as a semi-automatic. The group Copepoda, despite the limited taxonomic refinement ZooScan, obtained 2 genera and 1 species identified automatically. Among the seasons dry and wet groups Brachyura (zoea), Chaetognatha, and the Calanoid copepods (others), Temora spp., Oithona spp. and Euterpina acutifrons were those who had higher frequency of occurrence, appearing in more than 70% of the samples. Copepoda group showed the largest percentage of relative abundance in both seasons. There was no seasonal variation of total zooplankton, with an average density of 7826±4219 org.m-3 in the dry season, and 7959±3675 org.m-3 in the rainy season, neither between the types and phases of the tides, but seasonal differences were significant recorded for the main zooplankton groups. Vertical stratification was seen for the major zooplankton groups (Brachyura, Chaetognatha, Calanoida (other), Oithona spp, Temora spp. e Euterpina acutifrons). The scale of this stratification varied with the type (square or tide) and tidal phase (flood or ebb). The instantaneous transport was more influenced by current velocity, with higher values observed in spring tides to the total zooplankton, however, there was a variation of this pattern depending on the zooplankton group. According to the data import and export of total zooplankton, the outflow of organisms of the estuary was higher than the input. The results suggest that the estuary of Caravelas may influence the dynamics of organic matter to the adjacent coast, with possible consequences in National Marine Park of Abrolhos

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Dissertação de Mestrado, Gestão e Conservação da Natureza, 16 de Setembro de 2016, Universidade dos Açores.