Trace-Metal Concentrations in Coastal Marshes of the Lower Parana River and the Rio-de-La-Plata Estuary

Fil: Villar, Carlos Alberto. Instituto de Limnología Dr. Raúl A. Ringuelet (ILPLA). Facultad de Ciencias Naturales y Museo. Universidad Nacional de La Plata; ArgentinaFil: Stripeikis, J.. INQUlMAE. Facultad de Ciencias Exactas y Naturales. Universidad de Buenos Aires; ArgentinaFil: Tudino, M.. INQUlMAE. Facultad de Ciencias Exactas y Naturales. Universidad de Buenos Aires; ArgentinaFil: Dhuicque, L.. INQUlMAE. Facultad de Ciencias Exactas y Naturales. Universidad de Buenos Aires; ArgentinaFil: Troccoli, O.. INQUlMAE. Facultad de Ciencias Exactas y Naturales. Universidad de Buenos Aires; ArgentinaFil: Bonetto, Carlos Alberto. Instituto de Limnología Dr. Raúl A. Ringuelet (ILPLA). Facultad de Ciencias Naturales y Museo. Universidad Nacional de La Plata; Argentin

Nutrient concentrations and trophic state of small patagonian andean lakes

We analyzed nutrient, chlorophyll, and ionic concentrations in 17 lakes along a strip of land located in the rainy Andes Mountains and the ecotone with the dry Patagonian steppe, from 36 to 44° S latitude. Most of the sampled lakes had the ionic composition of Andean lakes and showed ultraoligotrophic conditions, while a few with the ionic composition of Patagonian Plateau lakes showed higher nutrient concentrations. Chlorophyll was correlated to P and N concentrations, but chlorophyll/TP ratio was lower than reported in previous worldwide surveys. A lithology dominated by igneous rock together with the remoteness and pristine character of the basins contribute to the oligotrophic status of the lakes. Two other factors appear to be important in maintaining the oligotrophic condition. Andisols, allophanic soils developed over volcanic ash deposits in the rainy areas, have large P retention capability and therefore decrease the load of P to the lakes. Natural dense Nothofagus spp. forests, with a geographical distribution coincident with that of the andisols, are efficient mechanisms for nitrogen retention through nitrogen resorption from senescent leaves.Instituto de Limnología "Dr. Raul A. Ringuelet

Nutrient concentrations and trophic state of small patagonian andean lakes

We analyzed nutrient, chlorophyll, and ionic concentrations in 17 lakes along a strip of land located in the rainy Andes Mountains and the ecotone with the dry Patagonian steppe, from 36 to 44° S latitude. Most of the sampled lakes had the ionic composition of Andean lakes and showed ultraoligotrophic conditions, while a few with the ionic composition of Patagonian Plateau lakes showed higher nutrient concentrations. Chlorophyll was correlated to P and N concentrations, but chlorophyll/TP ratio was lower than reported in previous worldwide surveys. A lithology dominated by igneous rock together with the remoteness and pristine character of the basins contribute to the oligotrophic status of the lakes. Two other factors appear to be important in maintaining the oligotrophic condition. Andisols, allophanic soils developed over volcanic ash deposits in the rainy areas, have large P retention capability and therefore decrease the load of P to the lakes. Natural dense Nothofagus spp. forests, with a geographical distribution coincident with that of the andisols, are efficient mechanisms for nitrogen retention through nitrogen resorption from senescent leaves.Instituto de Limnología "Dr. Raul A. Ringuelet

Effect of agrochemicals on macroinvertebrate assemblages in Pampasic streams, Buenos Aires, Argentina

Agricultural practices have been intensified in recent decades in Argentina. The Pampa plain is the main agricultural region of the country. The effect of increased application of agrochemicals on the invertebrate fauna of the Pampasic streams remains unreported. In the present study, we compared the abundance and composition of invertebrate assemblages in seven Pampasic streams with contrasting soil use in their basins. Two streams run through intensively cropped plots, two drain basins with livestock fields, while the other three are located within a biosphere Reserve. Higher nutrient and insecticide concentrations were measured in the streams draining cropped basins, related with pesticide applications and crop fertilization. The invertebrate assemblage composition of the cropped streams differed significantly from the others and between the two. Present evidence suggests that the impact of agrochemicals results in a change in composition with decreased abundance or absence of sensitive species such as Hyalellidae, Caenidae, Baetidae and Curculionidae and increased abundance of more tolerant taxa: Ostracoda, Glossiphoniidae (Hirudinea), Ancylidae (Gundlanchia), Ampullariidae (Pomacea canaliculata), Sphaeriidae and Dugesiidae. Available information suggests that macrophyte cover and composition also influence the invertebrate assemblages of the Pampasic streams.Facultad de Ciencias Naturales y MuseoInstituto de Limnología "Dr. Raúl A. Ringuelet

The Effect of Cypermethrin, Chlorpyrifos, and Glyphosate Active Ingredients and Formulations on <i>Daphnia magna</i> (Straus)

Acute effects of active ingredients (a.i.) and formulations (F) of widely used pesticides were assessed by means of the Daphnia magna toxicity test. Studied pesticides were the insecticides, cypermethrin and chlorpyrifos, and the herbicide, glyphosate. Results were analyzed and compared according to statistical endpoints (LCx) and log-probit regressions of toxicity data. The potency of acute toxicity followed the order: chlorpyrifos F > chlorpyrifos a.i. > cypermethrin F > cypermethrin a.i. ≫ glyphosate F > glyphosate a.i. Three to five orders of magnitude differences between the toxicity (µg/L to mg/L) of insecticides and the herbicide were observed. A pairwise comparison between a.i. and F indicated that all formulations were more potent. Additionally, for the case of glyphosate, evidence suggests that the adjuvant contributes to formulation toxicity rather than to the enhancement of a.i. potency.Facultad de Ciencias ExactasCentro de Investigaciones del MedioambienteFacultad de Ciencias Naturales y MuseoInstituto de Limnología "Dr. Raúl A. Ringuelet

Freshwater fishes of the Río de la Plata: current assemblage structure

Few studies have addressed the composition of fish assemblages of the freshwater Río de la Plata (RdlP) and have only been limited to species lists gathered over the last two centuries. As such inventories have never been reviewed or validated by fish sampling, the richness and structure of RdlP fish assemblage are poorly known. Hence, we conducted an exhaustive literature review and a fieldwork in six coastal points of Argentina to update the species composition and determine the hierarchical structure of the fish assemblage. From the 206 species registered in the literature, 48 were not confirmed, 13 were absent, five were taken as synonymized species, 29 were supported by literature and 107 were confirmed; one was an established exotic species, and three were a non-established exotic species. The findings reported here suggest that the fish assemblage currently comprises 141 species, including four new records. Analysis of fieldwork data in number and weight of fish captured resulted in an assemblage hierarchical structure of five dominant, 22 frequent, and 45 rare species; 16 dominant, 11 frequent, and 45 rare taxa, respectively. These results could be used as baseline to monitor, manage, and preserve neotropical fish species in their southern distribution boundary.El conocimiento de los ensambles de peces del sector dulceacuícola del Río de la Plata (RdlP) es escaso y limitado a listas de especies de compilaciones realizadas en los últimos dos siglos. Como esos inventarios nunca han sido revisados o validados mediante muestreos de peces, el conocimiento respecto de la riqueza y la estructura de los ensambles del RdlP resulta deficiente. Para ordenar y mejorar la información acerca de la riqueza y estructura de los ensambles de peces del área se realizó una revisión bibliográfica y un muestreo de campo para actualizar la composición de especies y determinar la estructura jerárquica del ensamble de peces. De las 206 especies colectadas de acuerdo a la bibliografía 48 se categorizaron como no reconfirmadas, 13 como ausentes, cinco como especies sinonimizadas, 29 como soportadas por la literatura, 107 como confirmadas, una exótica establecida y tres exóticas no establecidas. Los resultados sugieren que el ensamble de peces actualmente está compuesto por 141 especies, incluyendo cuatro nuevos registros. El análisis de los datos en número y en peso de los peces colectados mostró 5 especies dominantes, 22 frecuentes y 45 raras; y 16 dominantes, 11 frecuentes y 45 raras, respectivamente. Los resultados de este trabajo pueden ser usados como línea de base para el monitoreo, manejo y conservación de las especies de peces neotropicales en su límite de distribución sur.Fil: Maiztegui, Tomás. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Limnología "Dr. Raúl A. Ringuelet". Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. Instituto de Limnología; ArgentinaFil: Paracampo, Ariel Hernán. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Limnología "Dr. Raúl A. Ringuelet". Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. Instituto de Limnología; ArgentinaFil: Liotta, Jorge. Ministerio de Agricultura, Ganadería, Pesca y Alimento; ArgentinaFil: Cabanellas, Eva. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Limnología "Dr. Raúl A. Ringuelet". Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. Instituto de Limnología; ArgentinaFil: Bonetto, Carlos Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Limnología "Dr. Raúl A. Ringuelet". Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. Instituto de Limnología; ArgentinaFil: Colautti, Dario César. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Limnología "Dr. Raúl A. Ringuelet". Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. Instituto de Limnología; Argentin

Nutrient concentrations and trophic state of small patagonian andean lakes

We analyzed nutrient, chlorophyll, and ionic concentrations in 17 lakes along a strip of land located in the rainy Andes Mountains and the ecotone with the dry Patagonian steppe, from 36 to 44° S latitude. Most of the sampled lakes had the ionic composition of Andean lakes and showed ultraoligotrophic conditions, while a few with the ionic composition of Patagonian Plateau lakes showed higher nutrient concentrations. Chlorophyll was correlated to P and N concentrations, but chlorophyll/TP ratio was lower than reported in previous worldwide surveys. A lithology dominated by igneous rock together with the remoteness and pristine character of the basins contribute to the oligotrophic status of the lakes. Two other factors appear to be important in maintaining the oligotrophic condition. Andisols, allophanic soils developed over volcanic ash deposits in the rainy areas, have large P retention capability and therefore decrease the load of P to the lakes. Natural dense Nothofagus spp. forests, with a geographical distribution coincident with that of the andisols, are efficient mechanisms for nitrogen retention through nitrogen resorption from senescent leaves.Instituto de Limnología "Dr. Raul A. Ringuelet

Efecto de pulsos de toxicidad de cipermetrina sobre Simocephalus vetulus (Cladocera: Daphniidae)

Los plaguicidas utilizados en los cultivos pueden llegar a los cursos de agua por escorrentía superficial y producir pulsos de toxicidad para la fauna residente. El objetivo de este trabajo fue estudiar el efecto de repetidos pulsos de toxicidad subletal de cipermetrina sobre parámetros poblacionales de S. vetulus. Los organismos fueron expuestos a 0,02; 0,2 y 1 μg/L de cipermetrina por 90 minutos, luego transferidos a medio sin plaguicida y fueron monitorearon por 25 días. La exposición se repitió cada 7 días. Los organismos mostraron menor fecundidad acumulada y menor tasa de reproducción neta en todos los tratamientos, y menor tasa de crecimiento poblacional a la mayor concentración. Las concentraciones de exposición estuvieron dentro del rango de concentraciones ambientalmente realistas. Los resultados sugieren que el uso de plaguicidas en cultivos reducirá la densidad poblacional de S. vetulus en los arroyos adyacentes.Instituto de Limnología "Dr. Raúl A. Ringuelet

CCL20 and beta-defensin 2 production by human lung epithelial cells and macrophages in response to <i>Brucella abortus</i> infection

Both CCL20 and human β-defensin 2 (hBD2) interact with the same membrane receptor and display chemotactic and antimicrobial activities. They are produced by airway epithelia in response to infectious agents and proinflammatory cytokines. Whereas Brucella spp. can infect humans through inhalation, their ability to induce CCL20 and hBD2 in lung cells is unknown. Here we show that B. abortus induces CCL20 expression in human alveolar (A549) or bronchial (Calu-6) epithelial cell lines, primary alveolar epithelial cells, primary human monocytes, monocyte-derived macrophages and the monocytic cell line THP-1. CCL20 expression was mainly mediated by JNK1/2 and NF-kB in both Calu-6 and THP-1 cells. CCL20 secretion was markedly induced in A549, Calu-6 and THP-1 cells by heat-killed B. abortus or a model Brucella lipoprotein (L-Omp19) but not by the B. abortus lipopolysaccharide (LPS). Accordingly, CCL20 production by B. abortus-infected cells was strongly TLR2-dependent. Whereas hBD2 expression was not induced by B. abortus infection, it was significantly induced in A549 cells by conditioned media from B. abortus-infected THP-1 monocytes (CMB). A similar inducing effect was observed on CCL20 secretion. Experiments using blocking agents revealed that IL-1β, but not TNF-α, was involved in the induction of hBD2 and CCL20 secretion by CMB. In the in vitro antimicrobial assay, the lethal dose (LD) 50 of CCL20 for B. abortus (>50 μg/ml) was markedly higher than that against E. coli (1.5 μg/ml) or a B. abortus mutant lacking the O polysaccharide in its LPS (8.7 ug/ml). hBD2 did not kill any of the B. abortus strains at the tested concentrations. These results show that human lung epithelial cells secrete CCL20 and hBD2 in response to B. abortus and/or to cytokines produced by infected monocytes. Whereas these molecules do not seem to exert antimicrobial activity against this pathogen, they could recruit immune cells to the infection site.Facultad de Ciencias ExactasInstituto de Estudios Inmunológicos y Fisiopatológico

L'horticulture affecte les communautés de macroinvertébrés dans les cours d'eau drainants (Buenos Aires, Argentine)

The agrochemicals used on crops can reach watercourses, affecting water quality and biologic communities. The aim of this research was to study the effects of horticulture on the water quality and invertebrate assemblages of adjacent streams in Buenos Aires province, Argentina. Four streams draining horticultural basins were compared with another four considered less disturbed: two of the latter located in a Biosphere Reserve and the other two in extensive livestock-raising basins. Pesticides were detected in the horticulture-related streams, while nutrient concentrations were significantly higher than in the less-disturbed streams. The macroinvertebrate assemblages differed: the less-disturbed streams exhibited a significantly higher taxa richness and density. Hyalella sp. and Simocephalus vetulus were dominant, whereas Entomobryoidea, Dugessidae, and Glossiphoniidae were dominant in the horticulture-associated streams. Ephemeroptera (Caenis and Baetidae) were well represented in the less-disturbed streams and rare or absent in the horticulture-adjacent streams. Multivariate analysis indicated that the horticulture-impacted sites contained high nutrient concentrations and tolerant taxa, while the less-disturbed sites corresponded to lower nutrient concentrations and sensitive taxa. We propose Hyalella sp. and S. vetulus as water-quality indicators in pampean streams and conclude that intensive agrochemical applications in horticulture increase nutrient and pesticide loads affecting the macroinvertebrate assemblages of adjacent streams.Les produits agrochimiques utilisés sur les cultures peuvent atteindre les cours d'eau, affectant la qualité de l'eau et les communautés biologiques. Le but de cette recherche était d'étudier les effets de l'horticulture sur la qualité de l'eau et les assemblages d'invertébrés des cours d'eau adjacents dans la province de Buenos Aires en Argentine. Quatre cours d'eau drainant des bassins horticoles ont été comparés à quatre autres jugés moins perturbés : deux d'entre eux situés dans une réserve de biosphère et les deux autres dans de vastes bassins d'élevage. Des pesticides ont été détectés dans les cours d'eau liés à l'horticulture, tandis que les concentrations de nutriments étaient considérablement plus élevées que dans les cours d'eau moins perturbés. Les assemblages de macroinvertébrés différaient : les cours d'eau moins perturbés présentaient une richesse et une densité taxonomiques nettement plus élevées. Hyalella sp. et Simocephalus vetulus dominaient, tandis que les Entomobryoidea, Dugessidae et Glossiphoniidae dominaient dans les ruisseaux associés à l'horticulture. Les éphéméroptères (Caenis et Baetidae) étaient bien représentés dans les cours d'eau moins perturbés et rares ou absents dans les cours d'eau voisins de l'horticulture. L'analyse multivariée indique que les sites touchés par l'horticulture contenaient des concentrations élevées d'éléments nutritifs et des taxons tolérants, tandis que les sites moins perturbés correspondaient à des concentrations inférieures d'éléments nutritifs et à des taxons sensibles. Nous proposons Hyalella sp. et S. vetulus comme indicateurs de la qualité de l'eau dans les cours d'eau pampéens et concluons que les applications agrochimiques intensives en horticulture augmentent les charges de nutriments et de pesticides affectant les communautés de macroinvertébrés des cours d'eau voisins.Fil: Arias, Marina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Limnología "Dr. Raúl A. Ringuelet". Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. Instituto de Limnología; ArgentinaFil: Scalise, Ana Maria. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Limnología "Dr. Raúl A. Ringuelet". Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. Instituto de Limnología; ArgentinaFil: Solis, Marina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Limnología "Dr. Raúl A. Ringuelet". Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. Instituto de Limnología; ArgentinaFil: Paracampo, Ariel Hernán. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Limnología "Dr. Raúl A. Ringuelet". Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. Instituto de Limnología; ArgentinaFil: Indaco, Maria Mercedes. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Confluencia. Centro de Investigaciones en Toxicología Ambiental y Agrobiotecnología del Comahue. Universidad Nacional del Comahue. Facultad de Ciencias Agrarias. Centro de Investigaciones en Toxicología Ambiental y Agrobiotecnología del Comahue; ArgentinaFil: Fanelli, Silvia Laura. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Limnología "Dr. Raúl A. Ringuelet". Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. Instituto de Limnología; ArgentinaFil: Mugni, Hernan Diego. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Limnología "Dr. Raúl A. Ringuelet". Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. Instituto de Limnología; ArgentinaFil: Bonetto, Carlos Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Limnología "Dr. Raúl A. Ringuelet". Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. Instituto de Limnología; Argentin