Artículos, informes y presentaciones en Congresos
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Examinando Artículos, informes y presentaciones en Congresos por Autor "Bazzuri, María Elisa"
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Acceso Abierto The effects of hydraulic works and wetlands function in the Salado-River basin (Buenos Aires, Argentina)(2018) Bazzuri, María Elisa; Gabellone N. A.; Solari L. C.Man-made activities exert great influences on fluvial ecosystems, with lowland rivers being substantially modified through agricultural land use and populations. The recent construction of drainage canals in the upper stretch of the Salado-River basin caused the mobilization of huge amounts of salts formerly stored in the groundwater. The main aim of this work was to analyze the effect of the discharges of those canals into the Salado-River water, under different hydrologic conditions, and the role of the wetlands and shallow lakes placed along the canals’ system. Physicochemical variables were measured and water samples were taken during times of high water, mean flows, drought, and extreme drought. The environmental variables and the plankton development were related to the hydrologic regime and reached minimum values during floods because of low temperatures and dilution. Local effects on the water’s ionic composition became pronounced during droughts because of groundwater input. Nutrient concentrations were mainly associated with point wastewater discharges. Conductivity, ion concentrations, total plankton biomass, and species richness increased in the Salado-River downstream site, after the canals’ discharges. The artificial-drainage system definitely promotes the incorporation of salts into the Salado-River basin. In this scenario, a careful hydraulic management is needed to take into account this issue of secondary salinization that threatens the economic exploitation of the region. The wetlands present in this study acted as service environments not only helping to reduce salt, nutrient, and suspended-solid concentrations downstream but also contributing a plethora of species and plankton biomass into the Salado-River main course. - Documento de conferencia
Acceso Abierto Influencia ecológica de los canales de drenaje de la pampa arenosa en la cuenca superior del río Salado (Bs. As., Argentina)(2010) Bazzuri, María Elisa; Gabellone, Néstor Adrián; Solari, Lía C.La construcción de canales en la cuenca superior de río Salado ha provocado cambios en su red de drenaje, vinculando zonas arreicas de alto contenido salino provenientes de la Pampa Arenosa. Con el fin de estudiar sus consecuencias en la dinámica ecológica del río se analizaron parámetros físico-químicos y muestras de plancton para 5 sitios de muestreo en Mayo 2007. Los canales aportan al sistema aguas salinas, ricas en nutrientes, de bajo contenido en oxígeno disuelto (OD) y abundante plancton (cianobacterias coloniales, rotíferos y ciliados). En el río se observaron aguas con menor tenor salino, mayor OD y diferente composición planctónica (clorofitas clorococales y escaso zooplancton). En condiciones de aguas altas no se observaron modificaciones en las características del río aguas abajo del trasvase. Estos resultados muestran que el sistema de humedales asociados amortiguan los aportes alóctonos de las canalizaciones y su influencia no debería desestimarse en futuros proyectos hidráulicos. - Artículo
Acceso Abierto Variación estacional del fitoplancton en la cuenca inferior del Río Salado (provincia de Buenos Aires)(2008) Bazzuri, María Elisa; Gabellone, Néstor Adrián; Solari, Lía C.The main aim of this survey was to analyze seasonal variations in phytoplankton composition, relating its behaviour to temperature and conductivity, at El Destino (ED) sampling site in the Salado river lower-basin. A total of 28 phytoplankton samples were taken twice a week from 9/3 to 20/7/2004 and were analysed according to Utermöhl method. In total, 145 algae taxa were identified, although rare species were discarded in order to avoid statistical misinterpretation. Correlation coefficients and autocorrelation analyses (Q-Ljung-Box statistic) were performed in order to establish seasonal patterns of species abundance. Significant autocorrelations (p <0.05) were observed between phytoplankton species and temperature-conductivity patterns, thus illustrating their seasonal behaviour. Moreover, taxa were grouped according to their occurrence during different water temperature periods: (1) a ‘summer’ group, included 41 species that were well represented during warm-waters (>22ºC) like Planctonema lauterbornii, Chondrocystis dermochroa, Geminella interrupta, Chrooccocus spp., Merismopedia spp., among others; (2) a ‘winter’ group, which included 10 species whose highest densities were reached during the cold-waters period (<12ºC) for e.g. Binuclearia sp, Nitzschia fruticosa, Schroederia indica, Microcystis firma; (3) a ‘transitional’ group, of only 4 species with abundance peaks during ‘intermediate’ conditions (15.5ºC average) with Closteriopsis acicularis and Nodularia spumigena being the most remarkable; and (4) an ‘indifferent’ group, with 29 species of random behaviour whose autocorrelations remain within confidence limits, like Thorakochloris nygaardii, Pseudoanabaena limnetica, Monoraphidium giffithii, Scenedesmus linearis, etc. An evident seasonal succession was detected, having species substitution from summer warm-stagnant adapted species to cold-waters favoured ones, hence indicating different successional stages.