113 resultados para intertidal macroalgae
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Pós-graduação em Biologia Animal - IBILCE
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
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Pós-graduação em Ciências Biológicas (Zoologia) - IBRC
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This study aimed to evaluate some microhabitat characteristics of two populations of Tolypothrix distorta in streams from midsouthern region of Paraná State on a seasonal period. Each population was monthly investigated for the abundance of T. distorta and environmental variables such as depth, current velocity, irradiance, richness, and substrate diversity (H') using the quadrat technique for each sample unit (n = 7-10). For each segment the following physical and chemical water variables were also measured: temperature, oxygen saturation, specific conductance, pH, and turbidity. The seasonal period of higher abundance (percent cover) occurred during the months corresponding to summer/fall for both populations. The analyses also showed that populations had lower niche width and wide variation under the environmental conditions, characterizing the species as a generalist in the use of resources. Faster water flow and larger substrates favored the development of T. distorta, which may be related to the species morphological characteristics, thallus type that consists of tangled filaments formed by tuft and covered with thick gelatinous coats.
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The drainage basin of Cascavel River is almost entirely within the urban perimeter of Guarapuava, Paraná State, Brazil. Seven stream segments were sampled in two seasons (summer and winter). We found 12 taxa of macroalgae with a dominance of Chlorophyta (seven taxa) followed by Cyanophyta (three taxa), Heterokontophyta and Rhodophyta (one taxon each). Richness, diversity, and evenness were higher during the winter while the abundance and dominance were higher in the summer. Among the microenvironmental characteristics, the current velocity was the only one that differed significantly between the periods. The regression analysis revealed that the richness of the substrate was responsible for the variation in richness, diversity, evenness, and dominance during the summer period. During the winter the current velocity was responsible for the variation of species diversity. A cluster analysis of macroalgal communities did not group points in the same temporal period. The Canonical Correspondence Analysis (CCA) showed that the segments were close to each other because of the occurrence of one or a few species in common. The patterns of spatial and temporal distribution of stream macroalgae seem to be strongly influenced by microhabitat characteristics at different scales.However, they aresupported by regional variables.
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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 Química - IQ
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
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Conselho Nacional de Desenvolvimento Cientifico e Tecnológico (CNPq)
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The leptodactylid frog Thoropa miliaris, from SE Brazil, may live on rocky marine shore, where it thrives on terrestrial and marine invertebrates, and often moves into the intertidal zone. The osmotic concentration of plasma, muscle homogenate and urine of the frogs freshly captured on the rocky shore was higher than those collected far from the sea, or kept in captivity for 6-8 months on a diet free of marine items. Increase in body urea and sodium concentrations, reported in amphibians as a response to hyperosmotic environment, was not found in T. miliaris. Osmotic concentration of the frogs from rocky shore was variable though, ranging from 400 to 980 mOsm/l. Such variation in the osmotic concentration may reflect a territorial behavior for foraging sites, which would result in higher intake of marine items by individuals living closer to intertidal zone.
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Species of colonial green algae from 10 Conservation Units from the Southern Brazil were surveyed. The samplings were carried out in 105 stream reaches, consisting of 10 m length transects. In addition to biological data, some environmental variables were measured: depth, current velocity, water temperature, turbidity, specific conductance, pH, dissolved oxygen and nutrients (total nitrogen and orthophosphate). Three species of colonial green algae [Bohlin Ecballocystis pulvinata var. pulvinata, Tetraspora gelatinosa (Vaucher) Desvaux and T. lubrica (Roth) C Agard] were recorded and these species were described and illustrated. Based on the environmental data, it was observed some patterns of ecological distribution, including the occurrence of E. pulvinata var. pulvinata in environments with higher water temperature and current velocity values, while Tetraspora species typically occurred in environments with lower total nitrogen, orthophosphate and specific conductance values.
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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)