19 documents found, page 1 of 2
Phosphorus sequestration in Fe-rich sediments from two Brazilian tropical dam r...
FONSECA, R.; CANÁRIO, T.; MORAIS, M.; BARRIGA, F.This study investigates the important role of Fe-oxide/hydroxide-rich bottom sediments, from two Brazilian tropical reservoirs, on P sequestration from the overlying waters, which decreases the risk of eutrophication. Data on P fractionation indicates that P adsorption capacity of sediments is predominantly associated with Fe, followed by orthosphosphate adsorbed onto Al hydr(oxides) and onto different forms of...
Morphology and ecology of Achnanthidium caravelensis (Bacillariophyceae), a new...
NOVAIS, M. H; HLÚBIKOVÁ, D.; MORAIS, M.; HOFFMANN, L.; ECTOR, L.Abstract: A new benthic freshwater diatom species belonging to the genus Achnanthidium Kütz. has been recorded from several watercourses in the North of Portugal. Achnanthidium caravelense Novais et Ector is described as a new species based on light and scanning electron microscopic observations, as well as on its ecological preferences as reconstructed from field observations. The most characteristic morpholog...
Morphology and ecology of Achnanthidium caravelense (Bacillariophyceae), a new ...
NOVAIS, M.H.; HLÚBIKOVÁ, D.; MORAIS, M.; HOFFMANN, L.; ECTOR, L.A new benthic freshwater diatom species belonging to the genus Achnanthidium Kütz. has been recorded from several watercourses in the North of Portugal. Achnanthidium caravelense Novais et Ector is described as a new species based on light and scanning electron microscopic observations, as well as on its ecological preferences as reconstructed from field observations. The most characteristic morphological featu...
Hydrological Modeling in temporary streams: A case study in Pardiela basin, Sou...
PEDRO, A.; MORAIS, M.; ROSADO, J.; SILVA, H.; SERAFIM, A.; NEVES, R.; BRITO, D.; POTES, M.; SALGADO, R.; LILLEBØ, I.; CHAMBEL, A.The project “Conservation and rehabilitation strategies for temporary Mediterranean river corridors: a case study on Pardiela basin, southern Portugal (Guadiana basin)", is being carried out,with the collaboration of researchers from diverse scientific areas, in order to increase the knowledge on temporary streams. The project includes different approaches at reach and basin scales, regarding the study of tempo...
South Portugal Reservoirs – Status and major concerns
SILVA, H.; MORAIS, M.; ROSADO, J.; SERAFIM, A.; PEDRO, A.; SARMENTO, P.; FIALHO, A.In southern Portugal, the dry summers together with low precipitations and high temperatures highlight the importance of reservoirs, built mainly for water storage and to smoothing the interannual precipitation variability, in one of the driest regions in the country. According to the Water Framework Directive nº2000/60/CE, all states members are responsible for the classification of superficial water bodies us...
Geochemistry of metals in the bottom sediments of tropical dam reservoirs in Sa...
FONSECA, R.; PATINHA, C.; BARRIGA, F.; MORAIS, M.In tropical climates, the high rainfall and temperature, throughout the annual cycle, allow high leaching rates of metallic elements from the basin upstream, which accumulate in the reservoirs. However, the concentration of these elements in natural waters is usually lower than expected, due to the easiness of adsorption and coprecipitation in solid phases. We have studied two tropical dam reservoirs in Brazil,...
Transfering water among basins: an ecological assessment of Northeast Brazilian...
MELO, G.; SOBRAL, M. do C.; MORAIS, M.; TORREÃO, T.; MARWELL, D.The national project of the São Francisco river integration on northeast basins, lead by the Brazilian Ministry of National Integration, aims to transfer water from this river to different councils of the northeast semiarid region with limited water resources. This study aims to characterize the current ecological status of three northeast reservoirs that will receive water from the São Francisco River. In this...
Distribuição dos rios temporários em Portugal Continental
MORAIS, M.; Oliveira, Manuela; PEDRO, A.; ROSADO, J.; SILVA, H.; SERAFIM, A.Portugal situa-se a ocidente da Península Ibérica, (6º W e 10º W; 37º N e 42º N). É limitado a Norte e a Este por Espanha e a Ocidente e a Sul pelo Oceano Atlântico. Ocupa uma área de 89 300 km2, apresentando forma aproximadamente rectangular (560 x220 km). 0 clima de Portugal conjuga características atlânticas e mediterrânicas. A influência atlântica sente-se a Norte e é responsável por precipitações mais elev...
Influência de variáveis ambientais na comunidade fitoplanctônica em reservatóri...
MELO, G.; MORAIS, M.; SOBRAL, M. do. C.As informações restritas ao monitoramento dos parâmetros físico-químicos da qualidade da água dos rios e reservatórios não são suficientes para descrever a qualidade da água dos mesmos. A avaliação dos parâmetros biológicos tem sido freqüente na avaliação de impactos ambientais, pois produzem informações que não só indicam a presença de poluentes, mas como estes interagem com o meio ambiente, proporcionando uma...
Quantificação de cargas poluentes afluentes a um rio temporário de característi...
SILVA, H.; MORAIS, M.; Oliveira, Manuela; PEDRO, A.; ROSADO, J.; SERAFIM, A.Os sistemas aquáticos temporários são frequentes na região Mediterrânica assim como em regiões semi-aridas. São definidos como sistemas que durante um determinado período do ano não apresentam caudal superficial. Relativamente à estrutura e ao funcionamento destes sistemas, é obvio que tanto as comunidades terrestres como as aquáticas estão sujeitas a condições hidrológicas extremas, onde as características abi...