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| Registros recuperados: 11 | |
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| DORADOR,CRISTINA; CASTILLO,GABRIELA; WITZEL,K. P.; VILA,IRMA. |
| Rapel reservoir is an eutrophic system in Chile that has undergone a series of anthropogenic impacts in recent decades. To provide a better understanding of the processes occurring in the reservoir, we examined bacterial composition from surface sediments using traditional microbiology techniques and molecular biology tools. Our results showed significant temporal variation in the physical and chemical composition of the water column, but no depth-related differences during the study period. To detect temporal changes in bacterial composition, cultivable heterotrophic bacteria, heterotrophic iron oxidizing bacteria, and sulfate-reducing bacteria were extracted from the surface sediments and their concentration measured. Microbial diversity in sediments was... |
| Tipo: Journal article |
Palavras-chave: Sediments; Sulfate-reducing bacteria; 16S rDNA. |
| Ano: 2007 |
URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0716-078X2007000200007 |
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| GUERRERO,CLAUDIA J; POULIN,ELIE; MÉNDEZ,MARCO A; VILA,IRMA. |
| Los peces muestran una amplia diversidad de comportamientos alimentarios, algunas veces asociados con morfologías específicas, las cuales pueden reflejar adaptaciones para usar los recursos dependiendo de su hábitat. En los sistemas acuáticos aislados, los peces son un buen modelo de estudio para entender las relaciones tróficas. Este estudió evaluó la dieta de cinco especies de Orestias, las cuales habitan ocho sitios diferentes en la Región de Arica y Parinacota, Parque Nacional Lauca. Se analizaron 177 estómagos pertenecientes a las especies Orestias chungarensis, O. laucaensis, O. parinacotensis, O. piacotensis y Orestias cf agassii. Para los análisis se utilizaron descriptores cuantitativos de número de items presa y frecuencia de ocurrencia. Se... |
| Tipo: Journal article |
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| Ano: 2015 |
URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0717-65382015000100004 |
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| VILA,IRMA; VÉLIZ,DAVID. |
| Within the Annelida phylum, the Histriobdellidae Family groups freshwater polychaetes sharing an ancient Gondwanic relationship; very little is known about their life histories. Here we describe the life cycle of Stratiodrilus aeglaphilus, an epibiont of the crab Aegla laevis, which inhabits rivers of central Chile. All its life stages were found associated with A. laevis. The presence of a chitinous penis and its larger size permit distinguishing males from females. The observation of larvae/embryos at different development stages allowed us determining the absence of a free-swimming larvae stage in this species; recently hatched juveniles have movements similar to those of adults. S. aeglaphilus shows direct development; different embryo development... |
| Tipo: Journal article |
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| Ano: 2014 |
URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0717-65382014000200005 |
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| SCOTT,SERGIO; DORADOR,CRISTINA; OYANEDEL,JUAN PABLO; TOBAR,IGNACIO; HENGST,MARTHA; MAYA,GIANNINA; HARROD,CHRIS; VILA,IRMA. |
| This study examines the limnology and ecology of two high altitude wetlands, Lirima (19°51’24 S; 68°55’02 W; 4000 m asl) and Caya (20°37’21 S; 68°58’28 W; 3700 m asl), located in the Chilean Altiplano. Both wetlands are formed by the evaporitic remnant basins of paleolakes which occupied an extensive area of what today is known as the Altiplano. These systems have a negative hydrological balance, receiving their water from groundwater, snow melt and limited seasonal rains. An ongoing negative water balance and the sediment characteristics in the region have accelerated the salinization process in these systems, as shown by their present physicochemical characteristics. Nutrient values were typical of mesotrophic to... |
| Tipo: Journal article |
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| Ano: 2015 |
URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0717-65382015000100006 |
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| MARTÍNEZ,GINGER; CONTRERAS,MANUEL; VILA,IRMA. |
| La heterogénea morfología de los sistemas acuáticos regulados genera patrones de abundancia y gatilla una respuesta diferencial de los ensambles planctónicos. Un ejemplo de ello ocurre en el Embalse Rapel (34º10' S, 71º29' O). Un gradiente morfoedáfico longitudinal y condiciones hidrodinámicas localizadas producen complejidad espacial en esta cuenca dendrítica, lo que ha sido propuesto como probable factor causal de las diferencias de abundancia fitoplanctónica entre distintos sectores del embalse. En el presente estudio se proponen mecanismos y modelos conceptuales de abundancia de fitoplancton y para ello se describieron patrones de distribución de algas en tres sectores del embalse: Las Balsas, Alhué y El Muro. Posteriormente se... |
| Tipo: Journal article |
Palavras-chave: Heterogeneidad; Patrones espaciales; Fitoplancton; Embalse. |
| Ano: 2003 |
URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0716-078X2003000200010 |
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| FUENTES,LEOPOLDO; VILA,IRMA; CONTRERAS,MANUEL. |
| We evaluated the influence of water temperature (Tw) on the energy acquisition and use in the chilean silverside Basilichthys australis (Eigenmann 1927), an endemic species inhabiting freshwater ecosystems in Chile. We tested the effect of Tw (11.5, 14.0, 18.0, 22.0 and 26.0 °C) on food intake, digestibility, food transit time and metabolic rate. As expected, this study demonstrated that many physiological variables under study were significantly affected by Tw, as well as the net energy balance of this species. Nevertheless, the net energy balance was not strictly related to the range of Tws evaluated. At Tws lower than 14 °C the energy budget was depressed, because food intake was lower than at Tws between 14 and 26 °C, where food intake was higher and... |
| Tipo: Journal article |
Palavras-chave: Water temperature; Metabolic rate; Food consumption; Digestion; Energy budget; Basilichthys australis. |
| Ano: 2005 |
URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0716-078X2005000200014 |
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| VÉLIZ,DAVID; CATALÁN,LAURA; PARDO,RODRIGO; ACUÑA,PATRICIO; DÍAZ,ANGIE; POULIN,ELIE; VILA,IRMA. |
| There is still doubt as to the number of species of the freshwater Chilean ichthyofauna, 64 % of which have conservation problems. One of the groups is that of the silversides of the genus Basilichthys. Three morphological species of this genus have been described in Chile with disjoint distributions: Basilichthys semotilus, B. microlepidotus and B. australis; the latter two overlap in distribution only in the Aconcagua River and are not easily distinguishable by morphological and meristic characters. In order to evaluate the efficacy of identification of these species by molecular techniques, we analyzed the sequence of 9 % of the mitochondrial DNA (Control Region and COI) of individuals from the Loa River (21°41' S) to the Valdivia River (39°50' S),... |
| Tipo: Journal article |
Palavras-chave: COI; Control Region; Drainages; MtDNA; Silverside fish. |
| Ano: 2012 |
URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0716-078X2012000100004 |
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| SCOTT,SERGIO; PARDO,RODRIGO; VILA,IRMA. |
| Trichomycterus areolatus and Trichomycterus chiltoni are endemic siluriform fishes of Chile. They are the only Chilean species of this genus that live in sympatry and coexist in the Biobio basin. High trophic niche overlap between both species was found. Horn's index varied from 0.668 to 0.885 among seasons, without significant differences, and Schoener's index varied from 0.639 to 0.912. Also the discriminant analysis showed no significant differences in prey item between the two species. Trophic composition of T. chiltoni and T. areolatus consisted mainly in chironomid larvae and other aquatic invertebrates. At all seasons T. chiltoni showed the greatest prey richness. Principal component analysis (PCA) showed a high similarity between diets of T.... |
| Tipo: Journal article |
Palavras-chave: Diet; Sympatry; Trichomycterus areolatus; Trichomycterus chiltoni. |
| Ano: 2007 |
URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0716-078X2007000400004 |
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| DORADOR,CRISTINA; PARDO,RODRIGO; VILA,IRMA. |
| RESUMEN El lago Chungará, es el más austral y de mayor altura de los lagos altoandinos, está ubicado a 4.520 m de altitud en el altiplano chileno (18º14' S, 69º09' O); es un lago polimíctico-frío, con origen tectónico- volcánico y 34 m de profundidad máxima. Presenta variaciones reducidas de temperatura entre profundidades y estaciones del año (4 a 11 ºC), el promedio de temperatura anual se ha incrementado en 1,2 ºC entre los períodos 1986-1987 y 1998-1999. Entre los mismos períodos se observó una disminución significativa en el volumen del lago (_6,58 %) y consecuentemente en la profundidad máxima. Conjuntamente la salinidad aumentó significativamente con valores máximos de 1.464 µmhos y 2.650 µmhos para cada período. Estos cambios pueden ser las causas... |
| Tipo: Journal article |
Palavras-chave: Volumen; Temperatura; Salinidad; Fitoplancton. |
| Ano: 2003 |
URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0716-078X2003000100002 |
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| Registros recuperados: 11 | |
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