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Registros recuperados: 53
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Qualidade da água na área urbana do Rio Fervença IPB - Escola Superior Agrária
Teixeira, Amílcar; Geraldes, Ana Maria; Estevinho, Leticia M..
A qualidade ecológica do rio Fervença na área urbana de Bragança foi avaliada através do recurso a análises físicas, químicas e microbiológicas da água, complementadas com a caracterização do habitat aquático e ribeirinho e das comunidades de macroinvertebrados presentes ao longo do segmento de rio amostrado. Durante um período de dois anos recolheu-se informação em cinco locais de amostragem situados respectivamente a montante, no interior e a jusante da cidade, que permitiu detectar a existência de perturbações ambientais decorrentes do impacto provocado por fenómenos maioritariamente de origem antrópica. O input de substâncias no curso de água, nomeadamente no seu trajecto urbano, reflectiu-se no aumento substancial do teor em sais dissolvidos e em...
Tipo: ConferenceObject
Ano: 2009 URL: http://hdl.handle.net/10198/2919
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Régime alimentaire et croissance du barbeau iberique Barbus bocagei dans la reviere Sorraia (Portugal) IPB - Escola Superior Agrária
Geraldes, Ana Maria; Coelho, M.M.; Collares-Pereira, M.J..
Le barbeau ibérique Barbus bocagei est l’une des espèces les plus représentatives de l’icthyofaune de la rivière Sorraia (Bassin du fleuve Tejo). L’objectif de cette étude est de déterminer 1) les variations spatiales du régime alimentaire et de croissance linéaire de cette espèce entre différentes stations du sous-bassin de la Sorraia et 2) les variations de ces paramètres sur l’échelle temporelle dans deux de ces stations.
Tipo: Article
Ano: 1993 URL: http://hdl.handle.net/10198/2926
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Reservoirs: mirrors of the surrounding landscape? IPB - Escola Superior Agrária
Geraldes, Ana Maria; Boavida, Maria José.
To assess in what extent the environmental quality of aquatic systems reflect landscape features several water quality parameters were determined in two reservoirs. Concomitantly, the surrounding landscape was characterized and the existing potential sources of phosphorous and nitrogen runoff were identified and when possible estimated.
Tipo: Other
Ano: 2010 URL: http://hdl.handle.net/10198/2959
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Reservoirs: mirrors of the surrounding landscape? IPB - Escola Superior Agrária
Geraldes, Ana Maria; Boavida, Maria José.
To assess in what extent the environmental quality of aquatic systems reflect landscape features several water quality parameters were determined in two reservoirs. Concomitantly, the surrounding landscape was characterized and the existing potential sources of phosphorous and nitrogen runoff were identified and when possible estimated. Located in a mountainous area with negligible direct human influence, it was expected to find lower amounts of suspended organic matter and nutrients in Serra Serrada Reservoir. Water level fluctuations caused by intensive human water use, grazing and frequent land fires in the surrounding landscape can explain the unexpected high values of the mentioned parameters. In Azibo Reservoir the factors with greatest influence on...
Tipo: ConferenceObject Palavras-chave: Landscape; Water quality land use; Phosphorous and Nitrogen sources.
Ano: 2010 URL: http://hdl.handle.net/10198/2922
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Riparian ecotones and spatial variation of fish assemblages in Portuguese lowland streams IPB - Escola Superior Agrária
Collares-Pereira, M.J.; Geraldes, Ana Maria; Magalhães, M.F.; Coelho, M.M..
The first results of a long-term study on the role of riparian ecotones on the population and community dynamics of Iberian stream fish are presented and discussed . Riparian and macrophyte cover, bank slope and depth were among the most important variables affecting fish distribution . In general small fish favoured shallow areas with high macrophyte cover, whereas large fish dominated in deep areas with a high riparian cover . Slight spatial changes in terrestrial prey use were found suggesting a minor role for this resource during autumn . Finally, no significant spatial differences were found for linear growth, although some differences were obtained for the condition factor
Tipo: Article Palavras-chave: Riparian ecotones; Fish assemblages; Spatial variation; Iberian streams.
Ano: 1995 URL: http://hdl.handle.net/10198/713
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Seasonal water level fluctuations: Implications for reservoir limnology and management IPB - Escola Superior Agrária
Geraldes, Ana Maria; Boavida, Maria José.
With the purpose of finding out whether seasonal water level fluctuations could affect water quality in a reservoir subjected to those changes, trends in environmental variables and in phytoplankton and zooplankton assemblages were analysed. The reservoir’s hydrological cycle was characterized by three regimes. The maximum level phase lasted from January to the beginning of June, the emptying phase existed between mid-June to the beginning of September and the minimum level phase lasted from mid-September to the beginning of the first autumn/winter rain events. The highest values of total phosphorus, soluble reactive phosphorus, nitrate, water colour and chlorophyll a were found during the minimum level phase. The phytoplankton assemblage was dominated by...
Tipo: Article Palavras-chave: Nutrients; Phytoplankton and zooplankton assemblages; Reservoir management; Reservoirs; Water level fluctuation.
Ano: 2005 URL: http://hdl.handle.net/10198/711
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Technical assessment of the Portuguese national programme for dams with high hydropower potential (PNBEPH) IPB - Escola Superior Agrária
De Lembre, Hilde; Adriaenssens, Veronique; Lust, Arnoud; Devoldere, Kris; Willems, Sofie; Laureysens, Ilse; Olmeda, Concha; Geraldes, Ana Maria; Guimarães, Ana; Barrios, Violeta; Garcia, David.
The Portuguese National Programme for Dams with High Hydropower Potential (PNBEPH) foresees the construction of 10 new hydropower installations in several river basins. Among other relevant impacts that fall out of the scope of this study, hydropower projects can have an important impact on water quality - mainly on hydro-morphological conditions for aquatic life to sustain. According to the Water Framework Directive (WFD), the deadline for achieving a good status of surface waters is 2015. In the meantime, Member States should avoid taking action that could jeopardize the achievement of the objectives of the directive, notably the general objective of good status of water bodies. Derogations for building new infrastructure projects (notably dams) are...
Tipo: Report
Ano: 2009 URL: http://hdl.handle.net/10198/2916
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Variação de alguns parâmetros indicadores da qualidade da água em duas albufeiras da Serra da Estrela IPB - Escola Superior Agrária
Geraldes, Ana Maria; Boavida, Maria José.
Tipo: Article
Ano: 1998 URL: http://hdl.handle.net/10198/899
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What factors affect the pelagic cladocerans of the meso-eutrophic Azibo Reservoir? IPB - Escola Superior Agrária
Geraldes, Ana Maria; Boavida, Maria José.
The assemblage patterns of pelagic Cladocera species were investigated in a meso-eutrophic reservoir from January 2000 to December 2002. Trends of environmental factors (water temperature, conductivity, pH, and nutrient concentrations), as well as of biotic factors (availability of potentially edible phytoplankton and densities of herbivorous and carnivorous copepods) were assessed. Zooplankton community was dominated by Cladocera and Copepoda. Assemblage patterns for Cladocera were identified by performing a cluster analysis on abundance data of the dominant species: Daphnia longispina, Ceriodaphnia pulchella, Bosmina longirostris and Diaphanosoma brachyurum. In winter and spring, Daphnia was dominant. In early summer and end of autumn, Ceriodaphnia and...
Tipo: Article Palavras-chave: Zooplankton; Cladocera; Copepoda; Environmental factors; Phytoplankton availability.
Ano: 2004 URL: http://hdl.handle.net/10198/707
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Zooplancton de três piscinas biológicas cujas macrófitas apresentam diferentes graus de desenvolvimento IPB - Escola Superior Agrária
Geraldes, Ana Maria.
Tipo: Other
Ano: 2008 URL: http://hdl.handle.net/10198/880
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Zooplancton de três piscinas biológicas em que as macrófitas apresentam diferentes graus de desenvolvimento IPB - Escola Superior Agrária
Geraldes, Ana Maria.
As piscinas biológicas são pequenos lagos construídos onde são recriadas as condições ecológicas que ocorrem em ecossistemas lacustres naturais. Ao contrário das piscinas convencionais a depuração da água é realizada por filtros biológicos de macrófitas.
Tipo: ConferenceObject
Ano: 2008 URL: http://hdl.handle.net/10198/3844
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Zooplankton assemblages in two reservoirs: one subjected to accentuated water level fluctuations, the other with more stable water levels IPB - Escola Superior Agrária
Geraldes, Ana Maria; Boavida, Maria José.
The abundance, composition and dynamics of zooplankton were followed in two reservoirs of the River Douro catchment. The Serra Serrada Reservoir is subject to marked fluctuations in water levels. The highest values of total phosphorus, soluble reactive phosphorus, nitrate, water colour and chlorophyll a were found during the minimum level phase. Rotifera was dominant except in late summer and autumn when the cladoceran Ceriodaphnia quadrangula or the copepod Tropocyclops prasinus replaced them as the dominant zooplankton. Among the rotifers the most common taxa were Keratella cochlearis, Conochilus sp. and Asplanchna priodonta. Maximum rotifer density was about 80,000 ind m–3 in 2000, 200,000 ind m–3 in 2001 and 100,000 ind m–3 in 2002. Among the...
Tipo: Article Palavras-chave: Reservoirs; Water level fluctuations; Zooplankton assemblage structure; Water stored volume.
Ano: 2007 URL: http://hdl.handle.net/10198/715
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Zooplankton community and trophic state in Azibo and Serra Serrada Reservoirs (River Douro Portugal) IPB - Escola Superior Agrária
Geraldes, Ana Maria; Boavida, Maria José.
Tipo: ConferenceObject
Ano: 2000 URL: http://hdl.handle.net/10198/3854
Registros recuperados: 53
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