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| Registros recuperados: 36 | |
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| The increasing number of deteriorating old dams that need renovation or have lost their function make dam removal a viable management option. There are at least four major reasons for dam removal: safety, law and policy, economy, and ecology. Here we discuss 17 Swedish dams that were recently considered for removal. Because dam removal usually causes controversy, dam removal initiatives may succeed, fail, or result in a compromise such as a bypass channel for migrating fish. We identify and discuss three major obstructions to dam removal: funding, cultural-historical values, and threatened species. To facilitate dam removal, the reasons for, and the effects of, dam removal must be carefully explained, and the public and stakeholders must be kept... |
| Tipo: Peer-Reviewed Insight |
Palavras-chave: Controversies; Dam removal; Information; Obstructions; Reservoirs; Rivers; Stakeholder involvement; Sweden. |
| Ano: 2009 |
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| Carvalho,Luciana R. de; Sant'Anna,Célia L.; Gemelgo,Marcina C.P.; Azevedo,Maria Teresa de P.. |
| Billings and Guarapiranga Reservoirs were deeply affected by environmental disturbances, which more evident consequence are the cyanobacterial blooms. Microcystins are the most common cyanotoxin in freshwaters and more than 70 types are known. Different methods for microcystins analysis in water can be used, among which ELISA and HPLC are the most frequently employed. However, less sophisticated and more economic methods can also be used. This is the case of planar chromatography (thin-layer chromatography) method previously used in cyanotoxins purification but gradually replaced by others. Posterior optimization of the microcystin chromatography conditions and because of its simplicity, rapidity, efficiency and low cost, this method is again considered an... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Cyanobacteria; Drinking water; Microcystins; Planar chromatography; Reservoirs. |
| Ano: 2007 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-84042007000100014 |
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| Santos,Luciano Neves dos; Gonzalez,Alejandra Filippo; Araújo,Francisco Gerson. |
| The diet of Cichla monoculus (Bloch & Schneider, 1801) in Lajes's Reservoir, a major impoundment in Rio de Janeiro State, Brazil, was assessed, from fishes collected in 1994,1996 and 1999/2000. Gut contents in individuals was analyzed by the index of relative importance (IRI) which deals with numerical, gravimetrical and frequency of occurrence. Cichla monoculus showed a strong piscivorous habits feeding on Cichlidae, Characidae and Pimelodidae, in decreasing order of importance, with a remarkable cannibalism on young-of-the-year. Others minor items in the diet were Macrobrachium sp. and Odonata. Changes in feeding composition varied with reservoir's zones and seasons, with higher diversity in Autumn and peaks of cannibalism in lower zone during... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Cichla; Trofic ecology; Diet; Reservoirs; Freshwater fish; Condition factor; Feeding habits. |
| Ano: 2001 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0101-81752001000500015 |
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| Martins,Isabela; Sanches,Barbara; Kaufmann,Philip Robert; Hughes,Robert M.; Santos,Gilmar Bastos; Molozzi,Joseline; Callisto,Marcos. |
| Reservoirs are artificial ecosystems with multiple functions having direct and indirect benefits to humans; however, they also cause ecological changes and influence the composition and structure of aquatic biota. Our objectives were to: (1) assess the environmental condition of Nova Ponte Reservoir, Minas Gerais state, southeastern Brazil; and (2) determine how the aquatic biota respond to disturbances. A total of 40 sites in the littoral zone of the reservoir were sampled to characterize physical and chemical habitat, land use, and benthic macroinvertebrate and fish assemblages. The predominant type of land cover near the reservoir was natural vegetation. A total of 29 fish species and 39 macroinvertebrate taxa were collected, including eight alien... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Reservoirs; Water quality; Bioindicators; Physical habitat; Environmental quality. |
| Ano: 2015 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1676-06032015000100103 |
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| Perbiche-Neves,Gilmar; Rocha,Carlos E.F. da; Nogueira,Marcos G.. |
| Species richness and geographical distribution of Cyclopoida freshwater copepods were analyzed along the "La Plata" River basin. Ninety-six samples were taken from 24 sampling sites, twelve sites for zooplankton in open waters and twelve sites for zooplankton within macrophyte stands, including reservoirs and lotic stretches. There were, on average, three species per sample in the plankton compared to five per sample in macrophytes. Six species were exclusive to the plankton, 10 to macrophyte stands, and 17 were common to both. Only one species was found in similar proportions in plankton and macrophytes, while five species were widely found in plankton, and thirteen in macrophytes. The distinction between species from open water zooplankton and... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: La Plata River basin; Reservoirs; Rivers; Zooplankton. |
| Ano: 2014 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1984-46702014000300005 |
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| Duarte,Silvana; Paiva,Marco A. R.; Lara,Camila C.; Bemquerer,Marcelo P.; Araújo,Francisco Gerson. |
| The enzymatic activities involved in the digestion of proteins and carbohydrates were compared among three organs of the digestive track of two Siluriformes fish species, and between two areas: a reservoir, and an area downriver of it. Our aim was to test the hypothesis that the digestive organs of species with varied feeding habits have different enzymatic activities, and that the enzymatic activity differs among seasons and environmental conditions. The iliophagous/herbivorous species Hypostomus auroguttatus Kner, 1854 had higher trypsin-like, chymotrypsin-like peptidase and β-glucosidase activity in the intestine when compared with the omnivorous species Pimelodus maculatus Lacepède, 1803, whereas the latter had more hepatic trypsin-like activity than... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Enzymatic activity; Fishes; Physiology; Reservoirs; Siluriformes; Peptidases; Β-glucosidase. |
| Ano: 2013 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1984-46702013000300006 |
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| Registros recuperados: 36 | |
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