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| Baldisserotto,Bernardo; Copatti,Carlos Eduardo; Gomes,Levy Carvalho; Chagas,Edsandra Campos; Brinn,Richard Philip; Roubach,Rodrigo. |
| Fishes that live in the Amazonian environment may be exposed to several kinds of waters: "black waters", containing high dissolved organic carbon and acidic pH, "white waters", with ten fold higher Ca2+ concentrations than black waters and neutral pH, and "clear waters", with two fold higher Ca2+ concentrations than black waters and also neutral pH. Therefore, the aim of the present study was to analyze Ca2+ fluxes in the facultative air-breather Hoplosternum littorale (tamoatá) exposed to different Amazonian waters. Fishes were acclimated in well water (similar to clear water) and later placed in individual chambers for Ca2+ fluxes measurements. After 4 h, water from the chambers was replaced by a different type of water. Transfer of tamoatás to ion-poor... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Ion flux; Negro River; Amazon River; Acidic water. |
| Ano: 2009 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1679-62252009000300014 |
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| Rousseau, Tristan C.c.; Roddaz, Martin; Moquet, Jean-sébastien; Delgado, Helga Handt; Calves, Gérôme; Bayon, Germain. |
| We report mineralogical, elemental (major and trace elements) and SrNd isotopic data for suspended particulate matter (SPM) samples from the Amazon, Orinoco and Maroni Rivers collected on a monthly basis over a one-year long hydrological cycle. The aim of this study was i) to characterize the mineralogical and geochemical composition of major South American tropical rivers and ii) to evaluate the effect of seasonal hydroclimate variations and changes in sediment discharge on the composition of these SPM. In addition to displaying particular mineralogical and geochemical signatures (e.g. Al/Si ratios, weathering indices), the Amazon, Orinoco and Maroni SPM are characterized by marked differences in 87Sr/86Sr (0.7213 ± 0.0030, 0.7288 ± 0.0018 and... |
| Tipo: Text |
Palavras-chave: Major and trace elements; Nd-Sr isotopes; Suspended sediments; Yearly hydrological cycle; Amazon River; Orinoco River; Maroni River. |
| Ano: 2019 |
URL: https://archimer.ifremer.fr/doc/00498/60962/64370.pdf |
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| Bouchez, Julien; Gaillardet, Jerome; France-lanord, Christian; Maurice, Laurence; Dutra-maia, Poliana. |
| Residual solid products of erosion display a wide range of size, density, shape, mineralogy, and chemical composition and are hydrodynamically sorted in large river channels during their transport. We characterize the chemical and isotopic variability of river sediments of the Amazon Basin, collected at different water depths, as a function of grain size. Absolute chemical concentrations and Sr and Nd isotopic ratios greatly varies along channel depth. The Al/Si ratio, tightly linked to grain size distribution, systematically decreases with depth, mostly reflecting dilution by quartz minerals. A double-normalization diagram is proposed to correct from dilution effects. Elements define fan-shaped patterns and can be classified in three different groups with... |
| Tipo: Text |
Palavras-chave: Amazon River; Suspended sediments; Hydrodynamic sorting; Depth profiles; Grain size. |
| Ano: 2011 |
URL: https://archimer.ifremer.fr/doc/00214/32562/31016.pdf |
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| Chambault, Philippine; Giraudou, Lucie; De Thoisy, Benoit; Bonola, Marc; Kelle, Laurent; Dos Reis, Virginie; Blanchard, Fabian; Le Maho, Yvon; Chevallier, Damien. |
| The identification of the inter-nesting habitat used by gravid sea turtles has become a crucial factor in their protection. Their aggregation in large groups of individuals during the inter-nesting period exposes them to increased threats to their survival - particularly along the French Guiana shield, where intense legal and illegal fisheries occur. Among the three sea turtle species nesting in French Guiana, the olive ridley appears to have the most generalist diet, showing strong behavioural plasticity according to the environment encountered. The large amounts of sediments that are continuously discharged by the Amazon River create a very unusual habitat for olive ridleys, i.e. turbid waters with low salinity. This study assesses the behavioural... |
| Tipo: Text |
Palavras-chave: Lepidochelys olivacea; Equatorial Atlantic; Inter-nesting season; Behavioural synchrony; Amazon River. |
| Ano: 2017 |
URL: http://archimer.ifremer.fr/doc/00354/46507/46269.pdf |
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