Sample records for chile central maitencillo-cachagua

  1. Eighty Years of History of the Central Bank of Chile

    Vittorio Corbo; Leonardo Hernández


    The Central Bank of Chile was founded in 1925, to provide the country with an institution that could stabilize the currency, regulate interest and discount rates, and avoid disruptions in the country’s financial, industrial and economic development (Decree Law Nº486, August 22, 1925). But a weak institutional framework meant that the Bank, far from ameliorating these problems, aggravated them, leading to decades of high and persistent inflation. Inflation became under control only during the ...

  2. On the generation of coastal lows in central Chile

    Previous studies of the coastal-low occurrences in central Chile have been aimed at the formulation of a conceptual model to explain observed features in connection with applied studies. The most prominent weather pattern associated with CL occurrences, (type A), coincides with the onset of a warm, middle-troposphere ridge over central Chile, and a surface high over northern Argentina. The synoptic forcing of the low is related to weak frontal disturbances that travel equatorwards. They result in a thickening of the marine layer that becomes blocked by the coastal escarpment, at the time of the onset of the ridge aloft. The blocking of the stable air above the subsidence inversion by the Andes is also hypothesized. The analysis of the subsidence inversion, the geometry of the coastal and Andes mountain ranges, and a scale analysis of the non-dimensional governing equations for the generation of the coastal lows, following the approach of Reason and Steyn (1990); leads to the conclusion that both blocking actions are strong and persistent in central Chile. An interactive mechanism between the upper and lower blocking effects is postulated to explain the cyclonic vorticity and the initial steering of the coastal lows. The scale analysis of the governing equations for the propagation stage of the low suggests that, departing for the South African case, non-linearity is important here, and that solitary Kelvin waves could be expected. Theoretical phase propagation speeds and Rossby radii are found to range between 8 and 15 m s-1 and 100-250 km, respectively. The importance of strong southerly winds ahead of the low and weak winds at its trailing edge is also stressed, as another major departure from the coastal-low behaviour elsewhere. (author). 17 refs, 4 figs, 4 tabs

  3. Evolution of Parinacota volcano, Central Andes, Northern Chile

    Jorge E. Clavero R.


    Full Text Available Parinacota is an active composite stratovolcano located in the Central Andes of Northern Chile (18°S. During its earlier stage (Parinacota 1 unit, Late Pleistocene, 300-70? ka rhyolitic to andesitic magmas were erupted, forming a voluminous lava-dome complex with its associated pyroclastic fans (mainly block-and-ash flow deposits, essentially deposited towards the Upper Lauca basin (West. It later evolved to a steep-sided composite stratocone (Parinacota 2 unit, Late Pleistocene-Holocene, 70?-8 ka, mainly formed by andesitic lava flows and scoria tephra fallout deposits.Around 8 ka ago the ancestral Parinacota volcano, built during Parinacota 1 and 2, partially collapsed towards the west, in a single and catastrophic event generating the outstanding Parinacota Debris Avalanche deposit.Soon after the collapse a new stratocone started to build with the emission of andesitic lava flows and pyroclastic flows, and their associated fallout deposits (Parinacota 3 unit, Holocene, La evolución del volcán Parinacota, Andes Centrales, norte de Chile. El volcán Parinacota es un estratovolcán activo ubicado en los Andes Centrales del norte de Chile (18°S. Durante su primera etapa de evolución (Unidad Parinacota 1, Pleistoceno Superior, 300-70? ka emitió magmas de composición riolítica a andesítica, formando un voluminoso complejo de lavas-domo con abanicos piroclásticos asociados (esencialmente depósitos de bloques y ceniza, distribuidos principalmente hacia la parte superior de la cuenca del río Lauca (oeste. Posteriormente, evolucionó a un estratocono compuesto, de fuertes pendientes (Unidad Parinacota 2, Pleistoceno-Holoceno, 70?-8 ka, formado principalmente por lavas y depósitos de caída andesíticos. Aproximadamente hace 8 ka el volcán Parinacota ancestral, construido durante las unidades Parinacota 1 y 2, colapsó parcialmente hacia el oeste, en un evento único y catastrófico generando el Depósito de Avalancha de Parinacota. Poco

  4. Nitrogen fixation in four dryland tree species in central Chile

    Results are presented from a 5-year experiment using 15N-enriched fertilizer to determine N2 fixation in four tree species on degraded soils in a Mediterranean-climate region of central Chile in which there are 5 months of drought. Species tested included three slow-growing but long-lived savannah trees native to southers South America, (acacia caven, Prosopic alba and P. chilensis; Mimosoideae), and Tagasaste (Chamaecytisus proliferus ssp. palmensis; Papilonoideae), a fast-growing but medium-lived tree from the Canary Islands. Tagasaste produced four- to twenty-fold more biomass than the other species, but showed declining N2 fixation and biomass accumulation during the 5th year, corresponding to the juvenile-to-adult developmental transition. Nitrogen content was significantly higher in Tagasaste and Acacia caven than in the other species. The data revealed inter-specific differences in resource allocation and phenology of N2 fixation rarely detailed for woody plants in dryland regions. (author)


    Anthony Povilitis


    Full Text Available La única población sobreviviente del huemul en Chile central (Los Nevados de Chillán se encuentra en un descenso clásico hacia la extinción. Se utilizan los datos de prospecciones en terreno por el período entre 1975 a 2002 para estimar el tamaño, la estructura espacial y la tendencia de la población. Un análisis de la población en 1997 arrojó un mínimo de 60 huemules en 12 sitios, y una declinación de un 58% en la población durante un período de dos décadas. Prospecciones recientes entre 1998-2002 indican que la población de huemules ha continuado disminuyendo a 40 individuos en 11 sitios, lo que representa un descenso adicional de un 33%. Desde el año 1987, los huemules han desaparecido de 5, y posiblemente 8, sitios de hábitat primario. Solamente un sitio, el del Río Niblinto que es protegido, muestra un grupo del huemul más o menos estable. Las amenazas al huemul y a su hábitat, tal como los impactos del ganado doméstico, la urbanización, el desarrollo recreativo, la presencia de perros domésticos y las actividades industriales siguen sin disminución en la gran mayoría de los 26 sitios de hábitat primario necesario para la recuperación del huemul. Los datos actuales muestran claramente que una compaña de conservación más amplia es necesaria para resguardar y recuperar la especie en Chile central. Se requieren proteger los sitios de hábitat primario y los corredores conectantes de hábitat del huemul. Para realizar tal objetivo, se necesitan un fuerte compromiso e inversión financiera del gobierno y del sector privado. La creación de un nuevo parque nacional o gran reserva para el huemul y la biodiversidad en el sector de Los Nevados de Chillán, con beneficios relacionados al turismo, la educación pública, e investigaciones científicas, podría ayudar a atraer los recursos financieros que se necesitan para un programa exitoso de conservaciónABSTRACT The only surviving population of huemul in central

  6. Miocene Vetigastropoda and Neritimorpha (Mollusca, Gastropoda) of central Chile

    Nielsen, Sven N.; Frassinetti, Daniel; Bandel, Klaus


    Species of Vetigastropoda (Fissurellidae, Turbinidae, Trochidae) and one species of Neritimorpha (Neritidae) from the Navidad area, south of Valparaı´so, and the Arauco Peninsula, south of Concepción, are described. Among these, the Fissurellidae comprise Diodora fragilis n. sp., Diodora pupuyana n. sp., two additional unnamed species of Diodora, and a species resembling Fissurellidea. Turbinidae are represented by Cantrainea sp., and Trochidae include Tegula (Chlorostoma) austropacifica n. sp., Tegula (Chlorostoma) chilena n. sp., Tegula (Chlorostoma) matanzensis n. sp., Tegula (Agathistoma) antiqua n. sp., Bathybembix mcleani n. sp., Gibbula poeppigii [Philippi, 1887] n. comb., Diloma miocenica n. sp., Fagnastesia venefica [Philippi, 1887] n. gen. n. comb., Fagnastesia matanzana n. gen. n. sp., Calliostoma mapucherum n. sp., Calliostoma kleppi n. sp., Calliostoma covacevichi n. sp., Astele laevis [Sowerby, 1846] n. comb., and Monilea riorapelensis n. sp. The Neritidae are represented by Nerita (Heminerita) chilensis [Philippi, 1887]. The new genus Fagnastesia is introduced to represent low-spired trochoideans with a sculpture of nodes below the suture, angulated whorls, and a wide umbilicus. This Miocene Chilean fauna includes genera that have lived at the coast and in shallow, relatively warm water or deeper, much cooler water. This composition therefore suggests that many of the Miocene formations along the central Chilean coast consist of displaced sediments. A comparison with different fossil and Recent faunas from around the Pacific and South America indicates that the vetigastropod and neritid fauna from the Miocene of Chile has only minor affinities with taxa living near New Zealand, Argentina, and the tropical eastern Pacific at that time.

  7. Selenium concentration in compartments of aquatic ecosystems in Central Chile

    Pinochet, H.; Gregori, I. de; Cavieres, M.F. [Catholic University of Valparaiso, Valparaiso (Chile). Chemical Institute


    A study was conducted during 1995-96 to evaluate Se concentration in water, sediment, and plants from aquatic ecosystems of central Chile, an area particularly affected by mining activities. Samples were collected from Panquehue, Chagres, and Ocoa along the Acongua River (presumably receives discharges from a copper refinery and a copper mine). Samples were also collected from one site on the Puchuncavi Stream (directly contaminated by both a coal power plant and a copper refinery). In addition, samples were also collected from one site on the Limache Stream (an urban area with no Se-contaminating sources). The sediment and plant samples collected in Puchuncavi had higher Se levels, which were statistically different to the concentration in samples from other sites. Sediments from Puchuncavi and Ocoa had the highest levels of Se (520 plus or minus 46 and 440 plus or minus 10 {mu} g/kg, respectively) while the plant (Jussiaea repens (Ludwigia repens)) collected in Puchuncavi had an Se concentration 6.5 times higher than the sample collected in Panquehue (116 plus or minus 154 and 182 plus or minus 54 {mu} g/kg, respectively). Puchuncavi water had more acidic pH than water from the other sites thus decreasing Se solubility. Se concentrations in sediment and water collected in Chagres were lower than the concentration determined in sediment and water from either Ocoa or Panquehue. Plant/water and plant/sediment accumulation factors and a sediment/water distribution factor were similar for all sampling sites, except Puchuncavi (accumulation and distribution factors are higher than at the other sites). Hydrocotyle ranunculoides had practically the same plant/sediment accumulation factor at all sites while the accumulation factor for J. repens varied according to site. The samples collected in the Limache stream had Se at equal or even higher concentration than the other samples collected from presumably contaminated sites (except Puchuncavi). 19 refs.

  8. Chile.


    The background notes on Chile provide a statistical summary of the population, geography, government, and the economy, and more descriptive text on the history, population, government, economy, defense, and foreign relations. In brief, Chile has 13.3 million Spanish Indian (Mestizos), European, and Indian inhabitants and an annual growth rate of 1.6%. 96% are literate. Infant mortality is 18/1000. 34% of the population are involved in industry and commerce, 30% in services, 19% in agriculture and forestry and fishing, 7% in construction, and 2% in mining. The major city is Santiago. The government, which gained independence in 1810, is a republic with executive, legislative, and judicial branches. There are 12 regions. There are 6 major political parties. Suffrage is universal at 18 years. Gross domestic product (GDP) is $29.2 billion. The annual growth rate is 5% and inflation is 19%. Copper, timber, fish, iron ore, nitrates, precious metals, and molybdenum are its natural resources. Agricultural products are 9% of GDP and include wheat, potatoes, corn, sugar beets, onions, beans, fruits, and livestock. Industry is 21% of GDP and includes mineral refining, metal manufacturing, food and fish processing, paper and wood products, and finished textiles. $8.3 billion is the value of exports and $7 billion of imports. Export markets are in Japan, the US, Germany, Brazil, and the United Kingdom. Chile received $3.5 billion in economic aid between 1949-85, but little in recent years. 83% live in urban centers, principally around Santiago. Congressional representation is made on the basis of elections by a unique binomial majority system. Principal government officials are identified. Chile has a diversified free market economy and is almost self-sufficient in food production. The US is a primary trading partner. 49% of Chile's exports are minerals. Chile maintains diplomatic relations with 70 countries, however, relations are strained with Argentina and Bolivia. Relations

  9. Chile.


    Chile is a long (2650 miles), narrow (250 miles at widest point) country sandwiched between the Andes mountains and the Pacific. The northern desert is rich in copper and nitrates; the temperate middle region is agricultural and supports the major cities, including Santiago, the capital, and the port of Valparaiso; and the southern region is a cold and damp area of forests, grasslands, lakes, and fjords. The country is divided into 12 administrative regions. Chile's population of 12.5 million are mainly of Spanish or Indian descent or mestizos. Literacy is 92.3%, and the national language is Spanish. Infant mortality is 18.1/1000, and life expectancy is 68.2 years. 82% of the people are urban, and most are Roman Catholics. Chile was settled by the Spanish in 1541 and attached to the Viceroyalty of Peru. Independence was won in 1818 under the leadership of Bernardo O'Higgins. In the 1880s Chile extended its sovereignty over the Strait of Magellan in the south and areas of southern Peru and Bolivia in the north. An officially parliamentary government, elected by universal suffrage, drifted into oligarchy and finally into a military dictatorship under Carlos Ibanez in 1924. Constitutional government was restored in 1932. The Christian Democratic government of Eduardo Frei (1964-70) inaugurated major reforms, including land redistribution, education, and far-reaching social and economic policies. A Marxist government under Salvador Allende lasted from 1970 to 1973 when the present military government of General Pinochet Ugarte took power, overthrew Allende, abolished the Congress, and banned political parties. It has moved the country in the direction of a free market economy but at the cost of systematic violations of human rights. A new constitution was promulgated in 1981, and congressional elections have been scheduled for October, 1989. A "National Accord for Transition to Full Democracy" was mediated by the Catholic Church in 1985. The social reforms of the

  10. Chile.


    In 1985, Chile's population stood at 12 million, with an annual growth rate of 1.7%. 1984's infant mortality rate was 20/1000 live births and life expectancy was 67 years. The literacy rate was 94%. Of the work force of 3,841,000 in 1985, 15.9% were engaged in agriculture, forestry, and fishing; 31.3% were employed in industry and commerce; 38.6% were in the service sector; 8.7% worked in mining; and 4.4% were employed in construction. Chile's military junta is scheduled to be replaced by an elected legislature in 1990. The GDP was US $19.2 billion in 1984, with an annual real growth rate of 6.3%, and per capita GDP stood at US$1590. Inflation averages 23%. Industry comprises 21% of the GDP. Longterm prospects for the Chilean economy are influenced by a high debt service ratio, very low domestic savings and investment, the prospect of little or no increase in copper prices, and continuing problems in the domestic financial sector. In 1985-88, under the International Monetary Fund macroeconomic program, Chile will strive for moderate economic growth while managing its external debt servicing burden. PMID:12178144

  11. Chanco formation, a potential Cretaceous reservoir, central Chile

    Cecione, G.


    The Chanco embayment lies 300 km SSW of Santiago, Chile. The sequence within this basin above the metamorphic basement is: Chanco Formation (very clean sandstone), Quiriquina Formation (glauconitic sandstone, rich in organic matter), and Navidad Group (a very good caprock). This section thus contains reservoir, source and caprocks, and is therefore very promising for petroleum investigations. The offshore C-1 well yielded salt-water with gas shows, and two wells drilled onshore yielded shows of gas. The C-1 well lies on a gently-dipping EW-striking anticlinal structure, the presence of which makes the area very prospective.

  12. The evolution of seabirds in the Humboldt Current: new clues from the Pliocene of Central Chile.

    Martín Chávez Hoffmeister

    Full Text Available BACKGROUND: During the last decade, new Neogene fossil assemblages from South America have revealed important clues about the evolution of seabird faunas in one of the major upwelling systems of the world: the Humboldt Current. However, most of this record comes from arid Northern Chile and Southern Peru and, in consequence, our knowledge of the evolutionary history of seabirds in the temperate transitional zone is negligible. A new Late Pliocene assemblage of fossil birds from the coastal locality of Horcon in Central Chile offers a unique opportunity to fill this gap. PRINCIPAL FINDINGS: Isolated bones of a medium-sized penguin are the most abundant bird remains. Morphological and cladistic analyses reveal that these specimens represent a new species of crested penguin, Eudyptes calauina sp. nov. Eudyptes is a penguin genus that inhabit temperate and subantarctic regions and currently absent in central Chile. Additionally, a partial skeleton of a small species of cormorant and a partial tarsometatarsus of a sooty shearwater have been identified. CONCLUSION/SIGNIFICANCE: The Horcon fossils suggest the existence of a mixed avifauna in central Chile during the Pliocene in concordance with the latitudinal thermal gradient. This resembles the current assemblages from the transitional zone, with the presence of species shared with Northern Chile and Southern Peru and a previously unrecorded penguin currently absent from the Humboldt System but present in the Magellanic region. Comparison of Pliocene seabird diversity across the Pacific coast of South America shows that the Horcon avifauna represents a distinctive assemblage linking the living faunas with the Late Miocene ones. A comparison with the fossil record near the Benguela Current (west coast of southern Africa suggests that the thermic gradient could play an important role in the preservation of a higher diversity of cold/temperate seabirds in the Humboldt Current.

  13. The Evolution of Seabirds in the Humboldt Current: New Clues from the Pliocene of Central Chile

    Chávez Hoffmeister, Martín; Carrillo Briceño, Jorge D.; Nielsen, Sven N.


    Background During the last decade, new Neogene fossil assemblages from South America have revealed important clues about the evolution of seabird faunas in one of the major upwelling systems of the world: the Humboldt Current. However, most of this record comes from arid Northern Chile and Southern Peru and, in consequence, our knowledge of the evolutionary history of seabirds in the temperate transitional zone is negligible. A new Late Pliocene assemblage of fossil birds from the coastal locality of Horcon in Central Chile offers a unique opportunity to fill this gap. Principal Findings Isolated bones of a medium-sized penguin are the most abundant bird remains. Morphological and cladistic analyses reveal that these specimens represent a new species of crested penguin, Eudyptes calauina sp. nov. Eudyptes is a penguin genus that inhabit temperate and subantarctic regions and currently absent in central Chile. Additionally, a partial skeleton of a small species of cormorant and a partial tarsometatarsus of a sooty shearwater have been identified. Conclusion/Significance The Horcon fossils suggest the existence of a mixed avifauna in central Chile during the Pliocene in concordance with the latitudinal thermal gradient. This resembles the current assemblages from the transitional zone, with the presence of species shared with Northern Chile and Southern Peru and a previously unrecorded penguin currently absent from the Humboldt System but present in the Magellanic region. Comparison of Pliocene seabird diversity across the Pacific coast of South America shows that the Horcon avifauna represents a distinctive assemblage linking the living faunas with the Late Miocene ones. A comparison with the fossil record near the Benguela Current (west coast of southern Africa) suggests that the thermic gradient could play an important role in the preservation of a higher diversity of cold/temperate seabirds in the Humboldt Current. PMID:24621560

  14. Monitoring land cover change of the dryland forest landscape of Central Chile (1975–2008)

    Rey Benayas, José María; Schulz, Jennifer J.; Cayuela Delgado, Luis; Echeverría, Cristian; Salas Rey, Francisco Javier


    Las figuras que contiene el documento se localizan al final del mismo. Land cover and its configuration in the landscape are crucial components in the provision of biodiversity and ecosystem services. In Mediterranean regions, natural landscapes mostly covered by evergreen vegetation have been to a large extent transformed into cultural landscapes since long time ago. We investigated land cover changes in Central Chile using multi-temporal satellite imagery taken in 1975, 1985, 1999 and 20...

  15. Polygenetic development and paleoenvironmental implications of a Pleistocene calcrete at Tongoy, central northern Chile.

    M. Pfeiffer; J. Le Roux; H. Kemnitz


    The Norte Chico Region, in central northern Chile, is a particularly sensitive area to Quaternary climate changes because of its extreme climatic gradients. However, very little has been done to determine the late Pleistocene climatic conditions of the area. Calcretes are known to be important repositories of information on past ecosystems and environments. In the Tongoy paleobay, a series of four marine beach terraces have developed over a Mio-Pliocene calcareous formation since MIS 11 to th...

  16. Direct measurement and prediction of bulk density on alluvial soils of central Chile

    Manuel Casanova; Elizabeth Tapia; Oscar Seguel; Osvaldo Salazar


    The significance of soil bulk density (ρ) as a key indicator of soil quality was examined in this study. Bulk density values obtained by direct methods (clod, cylinder, and excavation) with three sample sizes (small, medium, and large) were compared with those obtained by 10 published pedotransfer functions (PTFs) for two alluvial soils (a massive fine-textured Fluventic Haploxeroll and an aggregated, coarse-textured Fluventic Haploxerept) of central Chile. With the exception of small cylinde...

  17. Provenance variations in the Late Paleozoic accretionary complex of central Chile as indicated by detrital zircons

    Hervé, F.; Calderón, M.; Fanning, C. M.; Pankhurst, R.J.; Godoy, E.


    We present detrital zircon UPb SHRIMP age patterns for the central segment (34–42°S) of an extensive accretionary complex along coastal Chile together with ages for some relevant igneous rocks. The complex consists of a basally accreted high pressure/low temperature Western Series outboard of a frontally accreted Eastern Series that was overprinted by high temperature/low pressure metamorphism. Eleven new SHRIMP detrital zircon age patterns have been obtained for meta-turbidites from the cent...

  18. Impact of Intrathermocline eddies on seamount and oceanic island off Central Chile: Observation and modeling

    Hormazabal, Samuel; Morales, Carmen; Cornejo, Marcela; Bento, Joaquim; Valencia, Luis; Auger, Pierre; Rodriguez, Angel; Correa, Marco; Anabalón, Valeria; Silva, Nelson


    In the Southeast Pacific, oceanographic processes that sustain the biological production necessary to maintain the ecosystems associated to seamounts and oceanic islands are still poorly understood. Recent studies suggest that the interaction of mesoscale and submesoescale eddies with oceanic islands and seamounts could be playing an important role in the time-space variability of primary production. In this work, research cruises, satellite data and Regional Ocean Modeling System (ROMS) results have been used to describe the main characteristics of intrathermocline eddies (ITE) and their impact on the Juan Fernández archipelago (JFA), off central Chile. The JFA is located off the coast of central Chile (33°S), and is composed of three main islands: Robinson Crusoe (RC), Alejandro Selkirk (AS) and Santa Clara (SC). Between the RC and AS are located the westernmost seamounts (JF6 and JF5) of the Juan Fernández archipelago. Satellite altimetry data (sea surface height from AVISO) were used to detect and track mesoscale eddies through eddy-tracking algorithm. Physical, chemical and biological parameters as temperature, salinity, dissolved oxygen and fluorescence were measured in the water column at JF5 and JF6, and along the coast off central Chile (30-40°S). Results from the research cruise exhibit the interaction between an ITE and the seamount JF6. Eddy-tracking results showed that the ITE observed at the JF6 was formed at the coast off central-southern Chile, traveled ~900 km seaward and after ~9 months reached the JF5 and JF6 region. Observations along the Chilean coast confirmed that the coast corresponds to the formation area of the observed ITE. In this region, ITEs are represented by subsurface lenses (~100 km diameter; 400 m thickness) of homogeneous salinity, nutrient rich and oxygen-poor equatorial subsurface water mass (ESSW) which is transported poleward by the Peru-Chile undercurrent in the coastal band and seaward by ITEs. The effect of ITEs on the

  19. Modelling the seasonal dynamics of the Peru-Chile Undercurrent off Central Chile (30-40°S)

    Vergara, Odette A.; Echevín, Vincent; Sepúlveda, Héctor H.; Colas, Francois; Quiñones, Renato A.


    The seasonal variability of the hydrology and the poleward subsurface Peru-Chile Undercurrent (PCUC) off the central Chilean coast (29-41°S) were examined using a high-resolution regional model. The model realistically reproduced observed sea level variability, such as intense anticyclonic eddies, the offshore intensification of the poleward flow and the reduced nearshore equatorward flow during autumn, as well as the equatorward intensification of nearshore meandering flow during spring. Values for geostrophic eddy kinetic energy were high along the coast between 30° and 37°S, and lower south of this area. The modelled poleward undercurrent showed latitudinal variability in velocity and transport. The maximum average transport reported was 0.8 Sv near 30°S, consistent with previous modelling studies and estimations derived from in situ observations. The poleward reduction in undercurrent strength was shown to be partly generated by the poleward decrease in wind stress curl and by the formation of a westward jet near 35°S associated with westward-propagating eddies. A Lagrangian analysis of the modelled water parcels transported by the undercurrent shows that only 14-20% of the subsurface floats transported by the undercurrent upwelled into the surface layer within the subsequent six months after their release. The floats remaining within the subsurface layer were likely transported further south by the current, offshore by westward-propagating eddies or equatorward by the deeper part of the surface coastal current.

  20. Las comunidades relictas de Gomortega keule (Gomortegaceae, Magnoliopsida en Chile central

    Sánchez Álvarez, Ana


    Full Text Available Some inventories were made in fourteen localities of Chilean températe forest with presence of Gomortega keule. All of them are situated on the west side of the Coastal Range in Central Chile. This species, the only member of the Gomortegaceae and an endemic to this área of Chile, is endangered because of habitat occupation by plantations of exotic species. In this paper, the floristic composition and ecology of these communities are described. The information about the distribution of this species is also updated.Se caracterizan florísticamente las comunidades de Gomortega keule existentes en la ladera occidental de la Cordillera de la Costa de Chile central. La riqueza florística de estas comunidades es muy elevada, con un total de 106 especies para las 14 localidades inventariadas, distribuidas en 56 familias y 83 géneros. La clara dominancia de fanerófitos (78,3%, y dentro de éstos la distribución de las distintas formas de crecimiento (17% de trepadoras y 3,8% de epífitos, condiciona tanto estructural como fisionómicamente a estas comunidades. El grupo de especies propias del bosque valdiviano es el más abundante, 42,5% de las especies, seguido de las de carácter esclerófilo típicas del Valle Central (14,2%. La conservación de G. keule, única especie de la familia Gomortegaceae, está completamente ligada al mantenimiento de estas comunidades, que en la actualidad están siendo sustituidas sistemáticamente por plantaciones forestales de especies exóticas en toda su área de distribución.

  1. A new species of Phymaturus (Iguania: Liolaemidae) of the palluma group from Central Chile

    Troncoso-Palacios, Jaime; Lobo, Fernando


    We examined specimens of Phymaturus from four locations in central Chile, between 34º50´S and 36º00´S (from Termas del Flaco and from Lircay and its surroundings), where the only recognized species is P. maulense. We found several differences in the scalation and in the color pattern among them. The samples from Lircay and its surroundings correspond to topotypes of P. maulense and two more populations assignable to this species (Termas del Campanario and Laguna del Maule, new records), but t...

  2. Reduction of firewood consumption by households in south-central Chile associated with energy efficiency programs

    Cities in the central-southern area of Chile face serious environmental pollution due to extensive use of firewood for heating. Low energy efficiency of constructions and cold climate increase the problem, which also affects native forests. The aims of this study are to characterize energy consumption in dwellings of this region, investigate the reduction potential, and study social and environmental consequences of high consumption of firewood. Actual energy consumption is studied with information from surveys, potential for reduction is modeled with software and other consequences are analyzed from previous studies. Results for the city of Valdivia show high firewood consumption per household, with a media bulk volume near 12 m3/year. Thermal regulations are softer compared with other countries. Moreover, around 85% of buildings were built before enforcing codes in 2007, and has almost no thermal protection. The reduction potential due to thermal improvements is found to be very high (62%) if buildings are refurbished to comply with the present Chilean Norm of 2007, but it reaches a 77% reduction if refurbished according to stricter foreign regulations. Therefore, an energy efficiency program strongly addressing existing buildings has the largest potential for reducing firewood use, and therefore mitigate environmental and health impacts. - Highlights: • High firewood consumption and environmental pollution in cities of south-central Chile. • High use of firewood due to inefficient constructions and soft thermal regulations. • Potential reduction of energy consumption up to 77% with more demanding regulations. • Policies should address building stock before thermal regulation, corresponding to 85%

  3. Growth of Stone pine (Pinus pinea L. European provenances in central Chile

    Loewe_Muñoz V


    Full Text Available Pinus pinea is characterized by phenotypic plasticity, tolerance to harsh soils and climates, but low differentiation in growth parameters and low genetic variability. Growth and cone production of six European stone pine provenances (two from Italy, three from Spain and one from Slovenia were analyzed in a field trial experiment established in central Chile. The study evaluated height, diameter at breast height (DBH and crown diameter growth of 147 nineteen-year-old trees per provenance, as well as fruiting variables (i.e., number of cones per tree and cone weight. Survival over the first 7 years was also evaluated. Provenances significantly differed in cone number per tree, cone weight, height and DBH growth, and crown diameter growth. Provenances were grouped according to growth and production variables: one group included the Italian and Slovenian provenances, the second group Andalucía and Sierra Morena (Spain, and the third included Meseta Castellana (Spain. Individual cone production was positively correlated with cone weight and other growth variables. Meseta Castellana provenance showed the highest growth and productivity. Our results provide useful information for the selection of P. pinea provenances to be used in new plantations in central Chile.

  4. Diet in pottery-making societies from Central Chile: The contribution of stable isotope analyses

    This is the first time that stable carbon, nitrogen and oxygen isotope analyses of human bones and teeth have been used to reconstruct subsistence and settlement patterns of prehispanic ceramic societies from Central Chile. Isotope analyses, unlike the evidence from botanical, faunal and artifactual remains from archaeological sites, and from dental and skeletal pathologies, gave information of which resources were really eaten by each individual during the last years of their life. The human data were evaluated against isotopic values of marine and terrestrial resources from central Chile. These results were interpreted taking into consideration different lines of paleodiet evidence. The main contributions are: empirical evidence of dietary differences according to cultural groups; low dependence on marine foods for most people living on the coast; indirect evidence of mobility strategies that show differences between Early and Late Intermediate societies; increased dependence on maize with time, especially among the Aconcagua people; gender differences in maize consumption for the same Aconcagua groups, men showing the greatest levels of maize intake. The results support some hypotheses, such as the difference in dietary patterns between contemporary Bato and Lolleo groups, contradict others, such as the supposed importance of marine diet for coastal inhabitants, and open new research questions for the future

  5. Revisiting mountain-building in the Andes of Central Chile: constraints from structural geology and thermochronology.

    Riesner, M.; Lacassin, R.; Simoes, M.; Armijo, R.; Carrizo, D.


    The Andes, one of the most significant reliefs on Earth, is the case example of a subduction-type mountain belt. In central Chile and western Argentina, the particular east-vergent structure of the Aconcagua fold-and-thrust belt (AFTB) is found atop a huge basement high with elevations > 4000 m, the Frontal Cordillera. Classical conceptual models consider the Andes as an east-vergent orogen, opposite to the Nazca subduction, and describe the exhumation of the Frontal Cordillera as an eastward in-sequence event that occurred late in the andean deformation (by ~10My). An alternative model recently challenged this view by proposing that the Andes have mainly a primary westward vergence. Within this scheme, the exhumation of the Frontal Cordillera would have begun earlier, by ~25My, synchronous with formation of the AFTB on the western side of the basement high. Here we test these two models by revisiting structural cross-sections of the Andes at the latitude of Santiago de Chile and of the Aconcagua (~33°S). We provide thermochronological constraints on the timing of exhumation of the Frontal Cordillera by (U-Th)/He dating on apatites retrieved from paleozoic granitoids along a 2,3km high nearly vertical section in the core of the basement high. Preliminary results suggest that the Frontal Cordillera exhumation was not a late event and likely began around 25 Ma. Therefore it appears to be synchronous with deformation within the AFTB and the westernmost fold-and-thrust belt at this latitude. We discuss these results and their implications while building a crustal-scale cross section of the range at the latitude of Santiago de Chile.

  6. Southern Hemisphere circulation signals in connection with winter rainfall forecasting in central Chile

    The possibility of detecting easterly propagating low frequency signals in the Southern Hemispheric circulation is explored in connection with the assessment of a possible seasonal rainfall forecast in central Chile. The analysis has focused on the seasonal variability associated with the biennial component of the Southern Oscillation (SO) and on the one resulting from superimposed intraseasonal oscillations, in relation with winter precipitation and individual rainfall events, respectively. Based on a previous work, relating wet winters to frequent blocks to the SW of South America during warm events of the SO, time-longitude cross sections of a 5-day average blocking index (BI) calculated from ECMWF 200 hPa daily hemispheric analyses for the period 1980-1987 are presented. A general eastward displacement of western and central Pacific positive BI areas seems to characterize the developing phase of warm SO events and vice versa, while intraseasonal variability patterns appear to be related to single rainstorms, either when the positive BI phase of the wave amplifies while crossing the western Pacific or when it reaches the far southeastern Pacific, frequently with a double block structure. It is concluded that the behaviour of both sources of variability is consistent with previously described teleconnection patterns for ENSO events in the southern winter, and that a primary prospect for winter precipitation and for the occurrence of relatively large individual rainstorms in central Chile could be obtained following the filtered BI and 500 hPa height anomalies in both time scales during the fall season. (author). 28 refs, 12 figs

  7. Comparative Study Of Focal Mechanisms In South Central Chile Before And After The 2010 Maule Earthquake

    Agurto, H.; Rietbrock, A.; Ryder, I. M.; Haberland, C. A.


    On 27 February 2010, a Mw=8.8 earthquake occurred off the coast of south central Chile rupturing nearly 500 km of the subduction zone plate interface. The earthquake also generated a tsunami and caused more than 500 fatalities. The largest earthquakes recorded have taken place along subduction margins (e.g. Chile 1960, 2010, Andaman-Sumatra 2004, Japan 2011) and understanding their rupture mechanisms and deformation regimes is therefore of vital importance. From November 2004 to October 2005, the TIPTEQ project ("From The Incoming Plate to megaThrust EarthQuake"; Rietbrock et al., 2007; Haberland et al., 2009) maintained a network of 120 seismic stations inland and 10 stations at sea between 37 and 39° lat. S., continuously-recording and monitoring the seismicity occurring in the area before the 2010 Maule earthquake. By using first motion polarities and moment tensor inversion we have computed and analyzed focal mechanisms for a subset of data from these records. We found thrust faulting along the subduction interface down to a depth of ~30 km, followed by a gap in the seismicity and then deeper earthquakes showing diverse faulting mechanisms more sparsely distributed within the subducting plate. We also see strike-slip crustal faulting occurring down to ~12 km depth within the area of the Lanalhue fault. The most striking observation is the presence of deep (40 km) normal faulting seismicity in the fore-arc, close to the trench. We have now started to analyze the International Maule Aftershocks Dataset (IMAD) of the 2010 earthquake in the southern rupture region. Again we observe thrust faulting in the subduction interface and a seismic gap between an upper and lower zone of seismicity along the interface. By comparison of the pre- and post-earthquake datasets we are investigating whether the Maule earthquake caused any changes in the style of deformation in this part of Chile. References Haberland, C., A. Rietbrock, D. Lange, K. Bataille, and T. Dahm (2009

  8. Biogeochemistry of sulfur and iron in Thioploca-colonized surface sediments in the upwelling area off central Chile

    Zopfi, Jakob; Michael E., Böttcher; Jørgensen, Bo Barker


    The biogeochemistry of sedimentary sulfur was investigated on the continental shelf off central Chile at water depths between 24 and 88 m under partial influence of an oxygen minimum zone. Dissolved and solid iron and sulfur species, including the sulfur intermediates sulfite, thiosulfate, and el...

  9. Environmental management in Chile: The power plants case; Gestion ambiental en Chile: Caso de las centrales termoelectricas

    Jadrijevic, Maritza [Comision Nacional del Medio Ambiente, (Chile)


    In this paper are presented the general aspects of the historic evolution o the legal norms on environmental matters in Chile; general aspects of the electric generation system and the instruments of environmental management currently applied in the fossil fueled power plants, such as: the assessment system of the environmental impact; compliance of the air quality and emissions Standards and plans for decontamination [Espanol] En este trabajo se dan a conocer aspectos generales de la evolucion historica de las normas juridicas en materia ambiental en Chile; aspectos generales del sistema de generacion electrica y los instrumentos de gestion ambiental que actualmente se aplican a las plantas de generacion termoelectricas, tales como: el sistema de evaluacion de impacto ambiental; cumplimiento de normas de la calidad de aire y de emision y, planes de descontaminacion

  10. Proposals to enhance thermal efficiency programs and air pollution control in south-central Chile

    Major cities in South-central Chile suffer high levels of particulate matter PM10 and PM2.5 due to combustion of solid fuels for heating. Exposure to these air pollutants is recognized as a major contribution to ill health in the region. Here we discuss new strategies to reduce air pollution. Regulations and subsidies focusing on improved combustion by providing drier wood fuel and better stoves have been in effect since 2007. However, air pollution due to combustion of wood fuel has been steadily rising, along with reports on health consequences. The paper analyzes a survey of 2025 households in the city of Valdivia, which found that wood fuel quality, stove renewal, and awareness of programs are strongly affected by income level, and that higher consumption of wood fuel is found in households already having better stoves and drier wood fuel. The analysis suggests that regulations intended to improve combustion are influenced by user's behavior and have limited potential for lowering pollution. We conclude that thermal refurbishment has a larger potential for improvement, not yet been implemented as an energy policy for the majority. Here we propose improvements and additions to current programs to enhance effectiveness and cover the whole social spectrum. - Highlights: • High levels of PM2.5 from wood combustion affect cities of south-central Chile. • Current programs on dry wood fuel and stoves renewal have not reduced air pollution. • Real operation of wood stoves strongly depends on user's behavior. • Buildings' energy efficiency has greater potential for reducing emissions. • Retrofit prevents degradation of native forest and improves indoor temperature

  11. Sr-Nd isotope changes of late cretaceous to early miocene volcanic rocks in central Chile (33oS)

    A longitudinal depression, the Central Valley, separates the Coast Range from the Andean Cordillera in central Chile. It contains volcanic and volcaniclastic rocks of Late Cretaceous to Tertiary age deposited in a continental environment, and partly eroded Tertiary volcanic complexes. The age of the rocks at the northern end of the Central Valley and their grouping in formations have been a long-standing controversy in Chilean geology (Thomas, 1958; Aguirre, 1960; Drake et al., 1976; Vergara and Drake, 1979; Thiele, 1980; Moscoso et al., 1982; Gana and Wall, 1997; Lopez-Escobar and Vergara, 1997; Selles, 1999). Here, we report new 40Ar/39Ar data and Sr-Nd isotope ratios for lavas, pyroclastic flows and associated subvolcanic rocks from this part of central Chile (au)

  12. The tomato borer, Tuta absoluta, invading the Mediterranean Basin, originates from a single introduction from Central Chile.

    Guillemaud, Thomas; Blin, Aurélie; Le Goff, Isabelle; Desneux, Nicolas; Reyes, Maritza; Tabone, Elisabeth; Tsagkarakou, Anastasia; Niño, Laura; Lombaert, Eric


    The Lepidopteran pest of tomato, Tuta absoluta, is native to South America and is invasive in the Mediterranean basin. The species' routes of invasion were investigated. The genetic variability of samples collected in South America, Europe, Africa and Middle East was analyzed using microsatellite markers to infer precisely the source of the invasive populations and to test the hypothesis of a single versus multiple introductions into the old world continents. This analysis provides strong evidence that the origin of the invading populations was unique and was close to or in Chile, and probably in Central Chile near the town of Talca in the district of Maule. PMID:25667134

  13. Riparian leaf litter processing by benthic macroinvertebrates in a woodland stream of central Chile Procesamiento de detritus ripariano por macroinvertebrados bentónicos en un estero boscoso de Chile central



    Full Text Available Leaf litter input from riparian landscapes has been identified as both a major energy flow to stream ecosystems and as a food source for stream macroinvertebrates. In riparian landscapes of woodland streams of central Chile, the native deciduous hardwoods are being artificially replaced by exotic coniferous trees at a large spatial scale. It is suggested that this process has a significant impact on the stream communities of central Chile. Today, exotic plantations occur throughout central Chile, with Pinus radiata (D. Don (Monterrey pine accounting for about 80 % of the more than 1,800,000 ha of exotic forests. The objective of this paper was to analyze the effect of the litter beds of a dominant native species (Nothofagus pumilio and an exotic species (P. radiata on the detritus processing carried out by benthic macroinvertebrates, in an experimental catchment of central Chile (Rucúe Creek; 36° 26'00" S, 71° 35'40" W. Results revealed that processing rates of native leaf packs are higher than rates of coniferous leaf packs, suggesting that the replacement of the native hardwoods by exotic coniferous riparian flora has an important impact on the stream energy flow in central Chile. The decay rate coefficients (k were 0.0072 for N. pumilio, and 0.0027 for P. radiata. The greater abundance and biomass of shredders per gram of leaf pack of native Nothofagus would explain the differences in leaf processing rates, especially through the activity of two Plecoptera Gripopterygidae, Limnoperla jaffueli and Antarctoperla michaelseniLa entrada de detritus foliar procedente de áreas riparianas ha sido reconocido como un componente importante en la energética de ecosistemas fluviales y como fuente de alimento de macroinvertebrados acuáticos. En áreas riparianas de esteros boscosos de Chile central los componentes nativos caducifolios están siendo artificialmente reemplazados a gran escala por coníferas exóticas, sugiriendo que este proceso tiene

  14. Mycotrophy in Gilliesieae, a threatened and poorly known tribe of Alliaceae from central Chile Micotrofía en Gilliesieae, una tribu amenazada y poco conocida de Alliaceae de Chile central



    The five known genera of Gilliesieae have their diversity center in the Mediterranean zone of central Chile, where many of their habitats are threatened by urban expansion, industrial and agroforestry activities, as well as other anthropogenic impacts. Very little is known about the biology of these particular geophytes, the majority of which currently have either vulnerable or endangered status, mainly due to their dispersed and small populations generally associated to remnants of native ve...

  15. Lavas Las Pataguas: volcanismo alcalino en el antearco andino del Mioceno Inferior, Chile central Lavas Las Pataguas: alkaline volcanism in the Early Miocene Andean forearc of central Chile

    Renate M Wall


    Full Text Available La presencia de rocas volcánicas del Mioceno Inferior en la cordillera de la Costa de Chile central constituye una singularidad ya que los afloramientos más occidentales del arco volcánico oligo-mioceno se encuentran 80 km al este. Lavas Las Pataguas (LLP; 33,8°S, se expone en 1,15 km², sin vestigios de un edificio volcánico ni conductos alimentadores. La presencia de túmulos del tipo `flow lobe tumuli', alineados y elongados en dirección este-oeste, indica un flujo local desde el oeste sobre una superficie de muy baja pendiente. Estos antecedentes sugieren un ciclo eruptivo de tipo fisural. La edad de LLP de ca. 18 Ma resulta intermedia entre las formaciones Abanico (34-20 Ma y Farellones (20-10 Ma y coetánea a facies litorales de la Formación Navidad, expuestas 20 km al oeste. LLP presenta contenidos de sílice de 52,8-54,5%, en el rango de las traquiandesitas basálticas, y su alto contenido de álcalis (6,21-6,26% de K2O+Na2O las sitúa en la serie alcalina de diferenciación. Destaca la clara diferencia con los productos toleíticos de la Formación Abanico, y los típicamente calcoalcalinos de la Formación Farellones. Estas lavas están significativamente enriquecidas en tierras raras livianas, con una razón La/Sm de 3,4 y un patrón plano de tierras raras pesadas. Tanto el contenido de sílice como de MgO, indican un estado de diferenciación avanzado dominado por cristalización fraccionada de olivino, clinopiroxeno y magnetita. El contenido de Ba y Nb señalaría una contribución significativa del manto litosférico. El Th, y la anomalía de Ta-Nb indicarían, también, un sello cortical. Su particular petrogénesis, así como su posición occidental y aislada en el antearco, podría explicarse como respuesta a la desaceleración de la convergencia con que culmina el ciclo extensional vigente hasta el Mioceno Inferior alto y que acompañó al volcanismo representado por la Formación Abanico. De este modo, las lavas

  16. A new species of Phymaturus (Iguania: Liolaemidae of the palluma group from Central Chile

    Troncoso-Palacios, Jaime


    Full Text Available We examined specimens of Phymaturus from four locations in central Chile, between 34º50´S and 36º00´S (from Termas del Flaco and from Lircay and its surroundings, where the only recognized species is P. maulense. We found several differences in the scalation and in the color pattern among them. The samples from Lircay and its surroundings correspond to topotypes of P. maulense and two more populations assignable to this species (Termas del Campanario and Laguna del Maule, new records, but the specimens from Termas del Flaco are a new species: P. damasense. It is characterized by: dorsal pattern of the male formed by a thin reticulation over greenish background color with yellowish-brown tail, subocular scale fragmented in three or four scales, scales in the anterior border of the auditory meatus are projected posteriorly, females have dark bars on the flanks (formed by small spots, enlarged scales in the center of the gular fold and may have precloacar pores. Also, we call attention to some Chilean populations of the genus Phymaturus referred in the literature which need to be assigned. Examinamos especimenes de Phymaturus procedentes de cuatro localidades de Chile central, entre los 34º50'S y 36º00'S (Termas del Flaco y los alrededores de Lircay, donde la única especie reconocida es P. maulense. Estas poblaciones muestran diferencias en la escamación y en el diseño de coloración. Las muestras de la cuenca del Maule corresponden a topotipos de P. maulense y dos poblaciones más asignables a esta especie (Termas del Campanario y Laguna del Maule, nuevos registros, mientras que las poblaciones del río Las Damas constituyen una nueva especie caracterizada por: diseño dorsal del macho formado por una reticulación oscura sobre un fondo verde con cola café-amarillenta, escama subocular fragmentada en tres o cuatro, escamas agrandadas en el borde anterior del meato auditivo (proyectadas posteriormente, hembras con escamas agrandadas en el

  17. Metallurgical traditions under Inka rule: a technological study of metals and technical ceramics from the Aconcagua Valley, Central Chile

    Plaza, M.T.; Martinón-Torres, M.


    The spread of the Inka state in the Aconcagua Valley (Central Chile) is thought to have been culturally mediated, avoiding military coercion, and thus leading to different forms of cultural acceptance, resistance or hybridisation. However, there has been no previous attempt to investigate the extent to which these interactions are reflected in the use of metals and metallurgical technologies. Here we present analytical work on metallic artefacts and technical ceramics from Cerro La Cruz and L...

  18. Methane in shallow cold seeps at Mocha Island off central Chile

    Jessen, Gerdhard L.; Pantoja, Silvio; Gutiérrez, Marcelo A.; Quiñones, Renato A.; González, Rodrigo R.; Sellanes, Javier; Kellermann, Matthias Y.; Hinrichs, Kai-Uwe


    We studied for the first time the intertidal and subtidal gas seepage system in Mocha Island off Central Chile. Four main seepage sites were investigated (of which one site included about 150 bubbling points) that release from 150 to 240 tonnes CH 4 into the atmosphere per year. The total amount of methane emitted into the atmosphere is estimated in the order of 800 tonnes per year. The gases emanated from the seeps contain 70% methane, and the stable carbon isotopic composition of methane, δ 13C-CH 4 averaged -44.4±1.4‰ which indicates a major contribution of thermogenic gas. Adjacent to one of the subtidal seeps, rocky substrates support a diverse community of microbial filaments, macroalgae, and benthic organisms. While stable carbon isotopic compositions of marine benthic organisms indicate a dominant photosynthesis-based food web, those of some hard-substrate invertebrates were in the range -48.8‰ to -36.8‰, suggesting assimilation of methane-derived carbon by some selected taxa. This work highlights the potential subsidy of the trophic web by CH 4-C, and that its emission to the atmosphere justifies the need of evaluating the use of methane to support the energy requirements of the local community.

  19. Landsat image and sample design for water reservoirs (Rapel dam Central Chile).

    Lavanderos, L; Pozo, M E; Pattillo, C; Miranda, H


    Spatial heterogeneity of the Rapel reservoir surface waters is analyzed through Landsat images. The image digital counts are used with the aim or developing an aprioristic quantitative sample design.Natural horizontal stratification of the Rapel Reservoir (Central Chile) is produced mainly by suspended solids. The spatial heterogeneity conditions of the reservoir for the Spring 86-Summer 87 period were determined by qualitative analysis and image processing of the MSS Landsat, bands 1 and 3. The space-time variations of the different observed strata obtained with multitemporal image analysis.A random stratified sample design (r.s.s.d) was developed, based on the digital counts statistical analysis. Strata population size as well as the average, variance and sampling size of the digital counts were obtained by the r.s.s.d method.Stratification determined by analysis of satellite images were later correlated with ground data. Though the stratification of the reservoir is constant over time, the shape and size of the strata varys. PMID:24243254

  20. Effects of maize cultivation on nitrogen and phosphorus loadings to drainage channels in Central Chile.

    Corradini, Fabio; Nájera, Francisco; Casanova, Manuel; Tapia, Yasna; Singh, Ranvir; do Salazar, Osval


    There are concerns about the impact of maize cultivation with high applications of nitrogen (N) and phosphorus (P) on water quality in surface waters in Mediterranean Central Chile. This study estimated the contribution of N and P from maize fields to nearby drainage channels and evaluated the effects in water quality. An N and P budget was drawn up for three fields managed with a maize-fallow system, El Maitén (20.7 ha), El Naranjal (14.9 ha) and El Caleuche (4.2 ha), and water quality variables (pH, EC, dissolved oxygen, total solids, turbidity, NO3-N, NH4-N, PO4(3-), COD, total N, total P and sulphate) were monitored in nearby drainage channels. The N and P balances for the three fields indicated a high risk of N and P non-point source pollution, with fertiliser management, soil texture and climate factors determining the temporal variations in water quality parameters. Elevated levels of NH4-N and PO4(3-) in the drainage channels were usually observed during the winter period, while NO3- concentrations did not show a clear tendency. The results suggest that excessive slurry application during winter represents a very high risk of N and P runoff to drainage channels. Overall, great emphasis must be placed on good agronomic management of fields neighbouring drainage channels, including accurately calculating N and P fertiliser rates and establishing mitigation measures. PMID:26490735

  1. Marine protected areas facilitate parasite populations among four fished host species of central Chile.

    Wood, Chelsea L; Micheli, Fiorenza; Fernández, Miriam; Gelcich, Stefan; Castilla, Juan Carlos; Carvajal, Juan


    1. Parasites comprise a substantial proportion of global biodiversity and exert important ecological influences on hosts, communities and ecosystems, but our knowledge of how parasite populations respond to human impacts is in its infancy. 2. Here, we present the results of a natural experiment in which we used a system of highly successful marine protected areas and matched open-access areas in central Chile to assess the influence of fishing-driven biodiversity loss on parasites of exploited fish and invertebrate hosts. We measured the burden of gill parasites for two reef fishes (Cheilodactylus variegatus and Aplodactylus punctatus), trematode parasites for a keyhole limpet (Fissurella latimarginata), and pinnotherid pea crab parasites for a sea urchin (Loxechinus albus). We also measured host density for all four hosts. 3. We found that nearly all parasite species exhibited substantially greater density (# parasites m(-2)) in protected than in open-access areas, but only one parasite species (a gill monogenean of C. variegatus) was more abundant within hosts collected from protected relative to open-access areas. 4. These data indicate that fishing can drive declines in parasite abundance at the parasite population level by reducing the availability of habitat and resources for parasites, but less commonly affects the abundance of parasites at the infrapopulation level (within individual hosts). 5. Considering the substantial ecological role that many parasites play in marine communities, fishing and other human impacts could exert cryptic but important effects on marine community structure and ecosystem functioning via reductions in parasite abundance. PMID:23855822

  2. Modelling the day to day wind variability offshore central Chile at about 30 deg. south

    Cycles of strengthening and relaxation of the winds offshore 30 degrees S at central Chile, are related to the propagation of coastal-lows, a year-round phenomenon occurring with periodicities of about one in five days. Simple physical modelling of the day to day variability of the alongshore wind component at a coastal strip extending offshore up to the Rossby deformation radius of these wave perturbations, is presented in terms of the relevant horizontal pressure gradients and the ageostrophic components arising from the coastal-low propagation. The results of 5-day composites of 8 wind-events each, at the winter and summer halves of the annual cycle, respectively; lead to a good agreement between the observed phase-lag of the winds with respect to the pressure forcing field, stressing the importance of the ageostrophic wind components at the extremes of the pressure wave perturbation associated with the passage of coastal-lows over the Point Lengua de Vaca (30 15 S) area. A possible contribution of the upwelling-favorable wind enhancement at the time of the pressure rise and subsequent fall, ahead of the coastal-low, is postulated through an upwelling-front low-level jet, that would be carried onshore and closer to the surface by the combination of the enhanced coastal upwelling, the coastal depression of the subsidence inversion base and the coastal ageostrophic wind components during the passage of the leading edge of the coastal lows. (author). 26 refs, 5 figs, 1 tab

  3. Soundscape of a management and exploitation area of benthic resources in central Chile

    Alfredo Borie


    Full Text Available Acoustic ecology is an emerging and poorly known field of research. Soundscape has been used to infer the behavior of several species in different environments and can serve as a reliable indicator of the habitat type and quality; also, it is believed that it is an important factor for larvae orientation in settlement areas. We used the passive acoustic method to evaluate the soundscape of a management and exploitation area of benthic resources, a rocky reef area in central Chile. It was possible to hear a continuous cracking sound during recording and underwater observations. We detected two distinct frequency bands with similar parameters during the night and day, a band between 90 and 300 Hz, which corresponded to the effects of sea waves (geophony, and a frequency band with a range of 1,500 to 2,700 Hz (biophony, with a fundamental frequency of 2,070 Hz. Both bands had similar energy (~88.0 dB re: 1V/µPa. These results show the relevant acoustic activity in the area, which may have important ecological implications for the recruitment of commercially important benthic resources.

  4. Analyzing Food-Related Life Satisfaction and other Predictors of Life Satisfaction in Central Chile.

    Schnettler, Berta; Lobos, Germán; Orellana, Ligia; Grunert, Klaus; Sepúlveda, José; Mora, Marcos; Denegri, Marianela; Miranda, Horacio


    This study aimed to assess the effect of satisfaction with food-related life on life satisfaction among inhabitants of the main municipalities of central Chile. A survey was applied to a sample of 1,277 people, distributed proportionally by municipality. The questionnaire included the following scales: SWLS (Satisfaction with Life Scale), SWFL (Satisfaction with Food-related Life) and the Health-Related Quality of Life Index (HRQOL). Questions were asked regarding eating habits inside and outside the home, time available for meals at home, the assessment of five sources of happiness and the demographic characteristics of those surveyed. An ordered logit model was proposed, in which the dependent variable was satisfaction with life. Satisfaction with life was significantly related to the respondent's socioeconomic status, self-perception of health, degree of satisfaction with food-related life, monthly food expenditure, time available for supper with the family (p consumption in fast food outlets (p < .10). Satisfaction with life in the study sample is related to aspects associated with health, family and eating, and the family interaction associated with eating may play an important role in overall satisfaction with life. PMID:26083311

  5. Classification of debris-covered glaciers and rock glaciers in the Andes of central Chile

    Janke, Jason R.; Bellisario, Antonio C.; Ferrando, Francisco A.


    In the Dry Andes of Chile (17 to 35° S), debris-covered glaciers and rock glaciers are differentiated from true glaciers based on the percentage of surface debris cover, thickness of surface debris, and ice content. Internal ice is preserved by an insulating cover of thick debris, which acts as a storage reservoir to release water during the summer and early fall. These landforms are more numerous than glaciers in the central Andes; however, the existing legislation only recognizes uncovered or semicovered glaciers as a water resource. Glaciers, debris-covered glaciers, and rock glaciers are being altered or removed by mining operations to extract valuable minerals from the mountains. In addition, agricultural expansion and population growth in this region have placed additional demands on water resources. In a warmer climate, as glaciers recede and seasonal water availability becomes condensed over the course of a snowmelt season, rock glaciers and debris-covered glaciers contribute a larger component of base flow to rivers and streams. As a result, identifying and locating these features to implement sustainable regional planning for water resources is important. The objective of this study is to develop a classification system to identify debris-covered glaciers and rock glaciers based on the interpretation of satellite imagery and aerial photographs. The classification system is linked to field observations and measurements of ice content. Debris-covered glaciers have three subclasses: surface coverage of semi (class 1) and fully covered (class 2) glaciers differentiates the first two forms, whereas debris thickness is critical for class 3 when glaciers become buried with more than 3 m of surface debris. Based on field observations, the amount of ice decreases from more than 85%, to 65-85%, to 45-65% for semi, fully, and buried debris-covered glaciers, respectively. Rock glaciers are characterized by three stages. Class 4 rock glaciers have pronounced

  6. Paleoenvironmental change in central Chile as inferred from OSL dating of ancient coastal sand dunes

    Andrade, Belisario; Garcia, Juan L.; Lüthgens, Christopher; Fiebig, Markus


    To present day, the climatic and geographic expression of glacials and interglacials in the semiarid coast of central Chile remains unclear. The lack of well dated paleoclimatic records has up to now precluded firm conclusions whether maximum glacials evident in the Andes mountain range probably coincide with wetter (e.g., pluvials) or drier conditions at the coast. The natural region locally known as "Norte Chico" represents a transitional semiarid area between the extreme Atacama Desert to the North and the wetter, Mediterranean-like type of climate, to the South. In this semiarid region of Chile several generations of eolian sand dunes, some of them separated by paleosoils, have been preserved. In addition to the occurrence of paleosoils, thick debris flow deposits in some places overly ancient dune bodies, likely indicating significant environmental changes during the formation of these archives. However, the exact timing of these processes within the mid to late Pleistocene and Holocene is still unclear. A key aspect is that some of the ancient dunes are recently hanging above rocky coastlines, where no supply of sand exists today, likely implying their formation during a lower than present, probably glacio-eustatically induced sea level. The location of the research area in a key mid-latitude region of the eastern Pacific in combination with the preserved landform record offers a chance to reconstruct climatic shifts during the Quaternary by studying the variability of morphogenetic conditions throughout time, in order to promote knowledge about possible forcing factors driving climatic variability. Within this pilot study, samples for optically stimulated luminescence (OSL) dating were taken from three different stratigraphic sections that denote a complex environmental variability as indicated by paleosoils and debris flow units intercalated in ancient sand dunes. First dating results inferred from OSL measurements using a post-IR IRSL (pIRIR) protocol for

  7. A Centralized Auction Mechanism for the Disability and Survivors Insurance in Chile

    Reyes H., Gonzalo

    As part of the pension reform recently approved in Chile, the government introduced a centralized auction mechanism to provide the Disability and Survivors (D&S) Insurance that covers recent contributors among the more than 8 million participants in the mandatory private pension system. This paper is intended as a case study presenting the main distortions found in the decentralized operation of the system that led to this reform and the challenges faced when designing a competitive auction mechanism to be implemented jointly by the Pension Fund Managers (AFP). In a typical bilateral contract the AFP retained much of the risk and the Insurance Company acted in practice as a reinsurer. The process to hire this contract was not competitive and colligated companies ended up providing the service. Several distortions affected competition in the market through incentives to cream-skim members by AFPs (since they bear most of the risk) or efforts to block disability claims. Since the price of this insurance is hidden in the fees charged by AFPs for the administration of individual accounts and pension funds there was lack of price transparency. Since new AFPs have no history of members’ disability and mortality profile the insurance contract acted as a barrier to entry in the market of AFP services, especially when D&S insurance costs reached 50% of total costs. Cross-subsidies between members of the same AFP, inefficient risk pooling (due to pooling occurring at the AFP rather than at the system level) and regulatory arbitrage, since AFPs provided insurance not being regulated as an insurance company, were also present. A centralized auction mechanism solves these market failures, but also gives raise to new challenges, such as how to design a competitive auction that attracts participation and deters collusion. Design features that were incorporated in the regulation to tackle these issues, such as dividing coverage into predefined percentage blocks, are presented

  8. Late Pleistocene to Holocene tephrostratigraphy of the Lonquimay Volcano, South Central Chile

    Gilbert, D.; Freundt, A.; Kutterolf, S.; Burkert, C.


    The Lonquimay Volcanic Complex (LVC) in South Central Chile (38.38°S, 71.58°W) is part of the Southern Volcanic Zone of the Andes, which formed in response to the subduction of the Nazca Plate beneath the South American Plate. During the course of its magmatic evolution, the LVC produced explosive eruptions documented in the succession of widespread tephra deposits, as well as large lava flows that originated from the main edifice and several adjacent minor eruptive centers. The last eruptive phase in Lonquimays volcanic evolution occurred from 1988-1990. It led to the formation of the Navidad cinder cone with its associated 10.2 km long lava flow, and a widely distributed tephra blanket of andesitic composition (Moreno and Gardeweg, 1989). During recent field work we reinvestigated and complemented the LVC tephrostratigraphy as originally established by Polanco (1998)by detailed logging of 22 outcrops and collecting 126 stratigraphically controlled samples that were analyzed for their matrix glass, mineral and bulk rock compositions. This data set allows us to verify and extend the field-based correlations, and to establish a tephrostratigraphy for the LVC that comprises 15 stratigraphic units (LQA-LQO) and provides a framework for ongoing investigations of the petrogenetic evolution of the LVC. The stratigraphic record identifies at least 13 explosive eruptions of VEI > 3 that occurred since the last glaciation period (17150 a BP, McCulloch et al. 2000). Magmatic compositions of the tephra deposits range from basaltic scoriae (51wt% SiO2) to evolved dacitic pumice lapilli layers (67wt% SiO2), and thus have a wider compositional range than the chemically distinct andesitic lavas (57-63wt%) of the LVC. The vertical succession of tephra compositions reflects four periods of progressive magmatic differentiation, each successively tapped by several eruptions. The maximum degree of fractionation reached during these periods increases to younger ages. The

  9. Antibacterial Activity, Antioxidant Effect and Chemical Composition of Propolis from the Región del Maule, Central Chile

    Nélida Nina


    Full Text Available Propolis is commercialized in Chile as an antimicrobial agent. It is obtained mainly from central and southern Chile, but is used for the same purposes regardless of its origin. To compare the antimicrobial effect, the total phenolic (TP, the total flavonoid (TF content and the phenolic composition, 19 samples were collected in the main production centers in the Región del Maule, Chile. Samples were extracted with MeOH and assessed for antimicrobial activity against Gram (+ and Gram (− bacteria. TP and TF content, antioxidant activity by the DPPH, FRAP and TEAC methods were also determined. Sample composition was assessed by HPLD-DAD-ESI-MS/MS. Differential compounds in the samples were isolated and characterized. The antimicrobial effect of the samples showed MICs ranging from 31.5 to > 1000 µg/mL. Propolis from the central valley was more effective as antibacterial than those from the coastal area or Andean slopes. The samples considered of interest (MIC ≤ 62.5 µg/mL showed effect on Escherichia coli, Pseudomonas sp., Yersinia enterocolitica and Salmonella enteritidis. Two new diarylheptanoids, a diterpene, the flavonoids pinocembrin and chrysin were isolated and elucidated by spectroscopic and spectrometric means. Some 29 compounds were dereplicated by HPLC-MS and tentatively identified, including nine flavones/flavonol derivatives, one flavanone, eight dihydroflavonols and nine phenyl-propanoids. Propolis from the Región del Maule showed large variation in antimicrobial effect, antioxidant activity and composition. So far the presence of diarylheptanoids in samples from the coastal area of central Chile can be considered as a marker of a new type of propolis.

  10. Post-earthquake coastal evolution and recovery of an embayed beach in central-southern Chile

    Martínez, Carolina; Rojas, Daniel; Quezada, Matías; Quezada, Jorge; Oliva, Ricardo


    Earthquakes and tsunamis are significant factors for change along active margin shores, and influence coastal evolution. The Chilean coast was affected in 2010 by a subduction earthquake with a magnitude of Mw 8.8 and also by a trans-Pacific tsunami, which generated violent geomorphologic changes and damaged homes. Following these events, the magnitude of the changes which affect Chile's central-southern coast (37°S) and the role of subduction earthquakes in coastal evolution on a historical scale were investigated. At Lebu bay (an embayed beach) data were generated for variations in time and space along the shoreline, topographical and bathymetric changes in the bay, and for morphodynamic littoral processes. Logarithmic and parabolic models were applied to the shoreline along with map overlays in order to determine changes. The shoreline processes were analyzed based on statistics for waves, tides and sediment transport for pre- and post-tsunami conditions. An average accretion rate of 2.80 m/year (1984-2010) was established for the shoreline, with a strong trend towards accretion in the last 30 years. A parabolic function best represented the general form of the shoreline, although the presence of a river in the concave zone affected the fit in this sector. Two factors controlled historical changes on the beach: one of anthropic origin in addition to the earthquake and tsunami on February 27th, 2010. The post-earthquake recovery was fast, and currently the beach is in a stable condition despite the inter-seismic subsidence process previous to the event. This coastal system showed a high resilience in the face of coastal geomorphological changes induced by high-impact natural disturbances. However, the opposite occurred in relation to changes induced by anthropogenic disturbances.

  11. Assessing the benefits and costs of dryland forest restoration in central Chile.

    Schiappacasse, Ignacio; Nahuelhual, Laura; Vásquez, Felipe; Echeverría, Cristian


    Investment in natural capital restoration is increasing as a response to the widespread ecological degradation of dryland forests. However, finding efficient mechanisms to promote restoration among private landowners is a significant challenge for policy makers with limited financial resources. Furthermore, few attempts have been made to evaluate the costs and benefits of restoration interventions even though this information is relevant to orient decision making. Hence, our goal was to estimate the benefits and costs of dryland forest restoration by means of reforestation with native trees in a study area in central Chile. To determine benefits we applied a Contingent Valuation questionnaire that allowed for the calculation of willingness to pay measures. Restoration costs were calculated based on market prices following existing technical recommendations developed for the study area. The results showed that the restoration project had a negative NPV irrespective of the discount rate applied in the analysis. Thus, the NPV varied between -US$71,000 and -US$258,000. The NPV attained positive results only for negative discount rates (US$15,039 for -2%) and only when the national subsidy available for forest restoration was taken into account. This shows that landowners in Colliguay do not have incentives for carrying out restoration interventions due to a classic market failure: that in which ecosystems are mismanaged because many of their benefits are externalities from the perspective of landowners. Overall, these results stress the need for developing new compensation mechanisms and enhancing those in existence, with the aim of making restoration competitive with other land uses. PMID:22325581

  12. Climate change adaptation in a highly urbanized snowmelt dominated basin in Central Chile

    Vicuna, S.; Bustos, E.; Merino, P.; Henriquez Dole, L. E.; Jansen, S.; Gil, M.; Ocampo, A.; Poblete, D.; Tosoni, D.; Meza, F. J.; Donoso, G.; Melo, O.


    The Maipo river basin holds 40% of Chile's total population and produces almost half of the country's Gross Domestic Product. The basin is located in the semiarid and snowmelt dominated central region of the country and, aside from the typical pressures of growth in developing country basins, the Maipo river basin faces climate change impacts associated with a reduction in total runoff and changes in its seasonality. Surface water is the main water source for human settlements, natural ecosystems, and economic activities including agriculture, mining and hydropower production. In 2012 a research project, called MAPA (Maipo Plan de Adaptacion), began with the objective of articulating a climate variability and climate change adaptation plan for the Maipo river basin. The project engaged at the beginning a group of relevant water and land use stakeholders which allowed for a good representation of critical aspects of an adaptation plan such as the definition of objectives and performance indicators, future land use scenarios, modeling of the different components of the system and design of adaptation strategies. The presentation will highlight the main results of the research project with a special focus on the upper catchments of the basin. These results include the assessment of impacts associated with future climate and land use scenarios on key components of the hydrologic cycle including snowmelt and glacier contribution to runoff and subsequent impacts on water availability for the operation of hydropower facilities, satisfaction of instream (recreation and aquatic ecosystem) uses and provision of water for the city of Santiago (7 million people) and to irrigate more than 100,000 hectares of high value crops. The integrative approach followed in this project including different perspectives on the use of water in the basin provides a good opportunity to test the varying degree of impacts that could be associated with a given future scenario and also understand

  13. Dieta del pez espada Xiphias gladius Linnaeus, 1758, en aguas oceánicas de Chile central en invierno de 2003 Diet of the swordfish Xiphias gladius Linnaeus, 1758 in oceanic waters off central Chile in winter 2003

    Christian M Ibáñez; Carlos González; Luis Cubillos


    Se analiza la dieta del pez espada en tres zonas de pesca en aguas oceánicas de Chile central durante el invierno de 2003, considerando como hipótesis que el tamaño de las presas se incrementa significativamente con el tamaño del depredador, conjuntamente con una disminución del número de presas. El estudio se realizó sobre la base de 48 estómagos de Xiphias gladius con contenido estomacal. Para su análisis se utilizó los descriptores cuantitativos de frecuencia de ocurrencia y método numéric...

  14. Application of the 137Cs technique to quantify soil redistribution rates in paleohumults from Central-South Chile

    The objective of the present study was to evaluate the applicability of the 137Cs technique in obtaining spatial distributed information on mean soil redistribution rates in Central-South Chile. For this purpose four fields of Palehumult soil and contrasting land use and management were selected in the Coastal Mountain Range of the 9th Region: Crop fields under subsistence and commercial management and non-permanent prairies under subsistence and commercial management. The spatial distribution of the soil redistribution rates obtained by the 137Cs method was similar to the one obtained by pedological observations. Also, annual sediment fluxes measured at experimental plots were similar to the erosion rates determined by the 137Cs method at adjacent points. The 137Cs technique is seen as an efficient method to obtain long-term soil redistribution rates under the climatic conditions and the soil type selected in Chile. In the future, it is necessary to study the applicability of the method under other climatic conditions and soil types occurring in Chile in which erosion is not so evident, and to adjust the method to optimise costs and benefits. (author)

  15. El aprecio por el paisaje y su utilidad en la conservación de los paisajes de Chile Central

    Gonzalo de la Fuente de Val; José A. Atauri Mezquida; José V. de Lucio Fernández


    La transformación del paisaje mediterráneo de Chile Central comienza a plantearse en la sociedad como una prioridad en todas sus dimensiones y funcione. Se consideran no sólo sus factores ecológicos, sociales, económicos sino también culturales, escénicos y afectivos. Se ha sugerido la percepción del paisaje como una pieza significativa para emprender nuevas formas de relación con el entorno. Este trabajo ilustra los resultados generales de un amplio estudio de preferencias paisajísticas y me...

  16. Palaeoenvironment reconstruction, volcanic evolution and geochronology of the Cerro Blanco subcomplex, Nevados de Chillan volcanic complex, Central Chile

    Mee, Katy; Gilbert, Jennie S.; McGarvie, David W.; Naranjo, Jose A.; Pringle, Malcolm S.


    Nevados de Chillán Volcanic Complex, central Chile, has been active for at least 640 ka—a period spanning a number of glacial and interglacial periods. Geologic mapping, radiometric dating and geochemical analysis have identified six new volcanic units and produced four new 40Ar/39Ar ages for Cerro Blanco, the northern subcomplex of Nevados de Chillán volcano. Compositions range from dacite to basaltic-andesite and a new geologic map is presented. Examination of lava fracture structures on bo...

  17. Syntectonic emplacement of the Middle Jurassic Concon Mafic Dike Swarm, Coastal Range, central Chile (33 degrees S)

    C. Creixell; M.A. Parada; Roperch, Pierrick; D. Morata; Arriagada, C; Arce, C.P. de


    The Concon Mafic Dike Swarm (CMDS) consists of basaltic to andesitic dikes emplaced into deformed Late Palcozoic granitoids during the development of the Jurassic arc of central Chile. The dikes are divided into an early group of thick dikes (512 in) and a late group of thin dikes (0.5-3 m). Two new amphibole Ar-40/Ar-39 dates obtained from undeformed and deformed dikes, constrain the age of emplacement and deformation of the CMDS between 163 and 157 Ma. Based on radiometric ages, field obser...

  18. A new species of Phymaturus (Iguania: Liolaemidae) of the palluma group from Central Chile

    Troncoso-Palacios, Jaime; Lobo, Fernando


    We examined specimens of Phymaturus from four locations in central Chile, between 34º50´S and 36º00´S (from Termas del Flaco and from Lircay and its surroundings), where the only recognized species is P. maulense. We found several differences in the scalation and in the color pattern among them. The samples from Lircay and its surroundings correspond to topotypes of P. maulense and two more populations assignable to this species (Termas del Campanario and Laguna del Maule, new records), but t...

  19. Water Erosion Prediction Using the Revised Universal Soil Loss Equation (RUSLE) in a GIS Framework, Central Chile Estimación de la Erosión Hídrica Empleando la Ecuación Universal de Pérdida de Suelo Revisada (RUSLE) y SIG en Chile Central

    Carlos A. Bonilla; Reyes, José L.; Antoni Magri


    Soil erosion is a growing problem in Central Chile, particularly in coastal dry lands, where it can significantly decrease the productivity of rainfed agriculture and forestry. In this study, the Revised Universal Soil Loss Equation (RUSLE) was integrated into a Geographic Information System (GIS), and used to evaluate the effects of different combinations of vegetative cover on soil erosion rates for Santo Domingo County in Central Chile. Implementing RUSLE in the GIS required a complete des...

  20. Estimation of real evapotranspiration and its variation in Mediterranean landscapes of central-southern Chile

    Olivera-Guerra, L.; Mattar, C.; Galleguillos, M.


    Evapotranspiration (ETd) is a key controller in the ecohydrological processes of semi-arid landscapes. This is the case of the dry land in Chile's central-southern zone, where forestry, farming and livestock activities must adapt to precipitation with considerable year-on-year variations. In this study, the spatial distribution of ETd was estimated in relation to the land use map and physical parameters of the soil. The ETd was estimated through the Simplified Surface Energy Balance Index (S-SEBI) using data from weather stations and remote data provided by the ASTER and MODIS sensors for November 2004 and 2006, respectively. The spatial variability of ETd was compared among different plant types, soil textural classes and depths using non-parametric statistical tests. In this comparison, the highest rates of ETd were obtained in the forest covers with values of 7.3 ± 0.8 and 8.4 ± 0.8 mm d-1 for 2004 and 2006, respectively. The lowest values were estimated for pastures and shrublands with values of 3.5 ± 1.2 mm d-1 and for crops with rates of 4.4 ± 1.6 mm d-1. Comparison of the ETd of the native forest covers and plantations of exotic species showed statistically significant differences; however, no great variation was noted, at least in the study months. Additionally, the highest rates of ETd were found in the clay loam textures (6.0 ± 1.8 and 6.4 ± 2.0 mm d-1) and the lowest rates in the sandy loam soils (3.7 ± 1.6 and 3.9 ± 1.6 mm d-1) for 2004 and 2006, respectively. The results enable analysis of the spatial patterns of the landscape in terms of the relation between water consumption, ET and the biophysical characteristics of a Mediterranean ecosystem. These results form part of the creation of tools useful in the optimization of decision-making for the management and planning of water resources and soil use in territories with few measuring instruments.

  1. Latitudinal discontinuity in thermal conditions along the nearshore of central-northern Chile.

    Tapia, Fabian J; Largier, John L; Castillo, Manuel; Wieters, Evie A; Navarrete, Sergio A


    Over the past decade, evidence of abrupt latitudinal changes in the dynamics, structure and genetic variability of intertidal and subtidal benthic communities along central-northern Chile has been found consistently at 30-32°S. Changes in the advective and thermal environment in nearshore waters have been inferred from ecological patterns, since analyses of in situ physical data have thus far been missing. Here we analyze a unique set of shoreline temperature data, gathered over 4-10 years at 15 sites between 28-35°S, and combine it with satellite-derived winds and sea surface temperatures to investigate the latitudinal transition in nearshore oceanographic conditions suggested by recent ecological studies. Our results show a marked transition in thermal conditions at 30-31°S, superimposed on a broad latitudinal trend, and small-scale structures associated with cape-and-bay topography. The seasonal cycle dominated temperature variability throughout the region, but its relative importance decreased abruptly south of 30-31°S, as variability at synoptic and intra-seasonal scales became more important. The response of shoreline temperatures to meridional wind stress also changed abruptly at the transition, leading to a sharp drop in the occurrence of low-temperature waters at northern sites, and a concurrent decrease in corticated algal biomass. Together, these results suggest a limitation of nitrate availability in nearshore waters north of the transition. The localized alongshore change results from the interaction of latitudinal trends (e.g., wind stress, surface warming, inertial period) with a major headland-bay system (Punta Lengua de Vaca at 30.25°S), which juxtaposes a southern stretch of coast characterized by upwelling with a northern stretch of coast characterized by warm surface waters and stratification. This transition likely generates a number of latitude-dependent controls on ecological processes in the nearshore that can explain species

  2. Strategies for improving thermal performance and visual comfort in office buildings of Central Chile

    Bustamante Gómez, Waldo; Encinas Pino, Felipe; Pino, Alan; Otarola, Roberto; PLEA 2011 - 27th International Conference on Passive and Low Energy Architecture: Architecture & Sustainable Development


    Overheating, high cooling energy demand and glare are recurrent problems in office buildings in Santiago and Valparaíso, Chile. Santiago (33°S) presents a Mediterranean climate, with a high temperature oscillation between day and night during cooling period. Valparaiso (33°S), by the coast, shows lower temperature fluctuation compared with Santiago. In order to evaluate impact on thermal and lighting performance of office buildings of these cities, a sensitivity study has been made. Variation...

  3. Composición, estructura y flujo energético del meiobentos frente a Chile central Composition, structure and energy flux of the meiobenthos off central Chile



    Full Text Available Se estudió la estructura de la meiofauna metazoaria (a nivel de grandes grupos taxonómicos y su rol en el flujo de energía en el subsistema bentónico frente a Concepción (~3630' S. Las muestras se recolectaron en mayo y noviembre de 1997 y mayo de 1998 en cinco sitios correspondientes a: interior de la Bahía de Concepción (28 m, boca de la bahía (35 m, plataforma interior (64 m, plataforma intermedia (88 m y plataforma externa (120 m. El periodo de estudio coincidió con el evento El Niño 1997-1998 (EN. El meiobentos resultó ser poco diverso a nivel de grandes grupos, pero con abundancias y biomasas moderadas a altas, en comparación con los valores promedio reportados en la literatura para el sublitoral fangoso. Nematoda fue el grupo dominante, con más de un 95 % (10³­10(4 ind 10 cm­2 de la densidad total, seguidos por Copepoda y Polychaeta. Las mayores abundancias y biomasas totales se encontraron siempre en la boca de la bahía, seguida de su parte interior y de la plataforma interior, mientras que los menores valores se ubicaron en la plataforma intermedia y externa. Frente a Concepción el meiobentos juega un importante rol en el flujo de energía a través del subsistema bentónico. Se estimó que estos organismos podrían estar remineralizando y/o convirtiendo a biomasa hasta un 36 y 45 % del carbono orgánico que llega desde la columna de agua a los sedimentos en el centro y en la boca de la bahía, respectivamente.The general objective of this study was to determine the structure of metazoan meiofauna (at a high taxonomic level and to estimate its role in the energy flux of the benthic sub-system off Concepción, Chile (~3630' S. Samples were collected in May and November 1997 and May 1998 at five sites located at the: inner Bay of Concepción (28 m, bay-mouth (35 m, inner-shelf (64 m, mid-shelf (88 m and outer-shelf (120 m. The study period coincided with the El Niño 1997-1998 (EN event. The diversity of the meiobenthos

  4. Social and economic factors of chile de agua (Capsicum Annum L. in three municipalities of the Central Valley in Oaxaca

    María de los Ángeles Rodríguez Mendoza


    Full Text Available This issue was carried out in the municipalities of San Pablo Huixtepec, San Sebastián Abasolo and Culiapan of Guerrero as part of the Central Valleys of Oaxaca, Mexico. We studied the production system of Agua Chile, using the technique of structured interview,information was obtained that allowed us to determine and meet the current models of socio-economic benefits in the form of productionof this vegetable. The importance of this study is that the chile de agua despite being a highly profitable crop has been little studied, so it is not known the extent that can have, there are markets that offer potentially greater benefits to farmers, therefore it is important to know the current situation of farmers in order to provide alternatives to improve their economic situation. The results indicate that according to the practices of peasant production and the low level of technology that includes the type of fertilizers, agrochemicals to combat pests and diseases and low use of agricultural machinery, yields of 3.97 t ha-1 allow total revenues are higher than the costs of production. Besides the existence of limited marketing networks (primarily in local markets and in the Oaxaca city, is a competitive crop in terms of profitability for finance of small production units and furthermore, it is growing factor relevant food security of farming families.

  5. Geographic variation in diversity of wave exposed rocky intertidal communities along central Chile Variación geográfica de la biodiversidad en hábitats intermareales rocosos de Chile central



    Full Text Available Along the coast of central Chile, geographic trends of diversity have been inferred from literature compilations and museum collections based on species range limits for some taxonomic groups. However, spatially-intensive field-based assessments of macrobenthic species richness are largely missing. Over the course of a multiyear study (1998-2005, we characterized latitudinal patterns of rocky intertidal diversity at 18 sites along the coast of central Chile (29-36° S. At each site, the number of sessile and mobile macrobenthic species was quantified in 0.25 m² quadrats. Two estimators of local (alpha diversity were used: observed local species richness, calculated from the asymptote of a species-rarefaction curve, and the Chao2 index, which takes into account the effect of rare species on estimates of local richness. We identified a total of 71 species belonging to 66 genera for a total of 86 taxa. The most diverse groups were herbivorous mollusks (27 taxa and macroalgae (43 taxa. Diversity showed a complex spatial pattern with areas of high species richness interspersed with areas of low richness. In accordance with previous work, we found no trend in the number of herbivorous mollusks and an inverse and significant latitudinal gradient in the number of algal species. Our results highlight the need for taxonomically diverse assessments of biodiversity of the dominant taxa that conform intertidal communities.A lo largo de la costa de Chile central, los patrones geográficos de diversidad han sido inferidos a partir de revisiones literarias y colecciones de museos para algunos grupos taxonómicos. Sin embargo, aun no contamos con una evaluación integral, y en terreno, de la riqueza de especies macrobentónicas intermareales. En un estudio de largo plazo conducido entre 1998 y 2005 caracterizamos los patrones latitudinales en la biodiversidad del intermareal rocoso en 18 sitios a lo largo de la costa de Chile central (29-36° S. En cada sitio

  6. Mycotrophy in Gilliesieae, a threatened and poorly known tribe of Alliaceae from central Chile Micotrofía en Gilliesieae, una tribu amenazada y poco conocida de Alliaceae de Chile central



    Full Text Available The five known genera of Gilliesieae have their diversity center in the Mediterranean zone of central Chile, where many of their habitats are threatened by urban expansion, industrial and agroforestry activities, as well as other anthropogenic impacts. Very little is known about the biology of these particular geophytes, the majority of which currently have either vulnerable or endangered status, mainly due to their dispersed and small populations generally associated to remnants of native vegetation. As mycorrhizal associations are essential for soil resource acquisition and stress mitigation in most plants, our objective was to assess the hitherto unknown mycotrophic status of ten species of Gilliesieae from central Chile by qualitative and quantitative assessment of intraradical fungal structures. All sampled genera (Gethyum, Gilliesia, Miersia, Solaria, Speea showed regular presence of arbuscular mycorrhiza, while other mycorrhizal or putatively mutualistic associations, like dark septate endophytes, were practically absent. Mycorrhizal colonization of fine roots reached a mean of ca. 45 % across all examined taxa, with highly variable values ranging from 9 % to 82 % in Miersia tenuiseta and Gilliesia curicana, respectively. The high level of mycorrhization indicates that arbuscular mycorrhiza should be considered for conservation strategies of threatened species or biotechnological use in plant propagation. The main future task is the identification of the associated fungal taxa.Los cinco géneros conocidos de Gilliesieae tienen su centro de diversidad en la zona mediterránea de Chile central, donde muchos de sus hábitats están amenazados por la expansión urbana, actividades industriales y agroforestales, así como otros impactos antropogénicos. Se sabe muy poco sobre la biología de estas particulares geófitas, que en la actualidad tienen en su mayoría estatus de vulnerable o en peligro de extinción, debido a sus poblaciones

  7. Latencia y banco de semillas en plantas de la región mediterránea de Chile central Seed bank and dormancy in plants of the Mediterranean region of central Chile



    Full Text Available Los bancos de semillas en las regiones mediterráneas presentan rasgos particulares que los distinguen de bancos de otras regiones del mundo. El banco de semillas es concentración de propágulos viables enterrados en el suelo por períodos variables de tiempo. Los bancos de semillas del matorral de Chile central son principalmente transitorios y funcionalmente semejantes a los bancos presentes en otros ecosistemas mediterráneos no perturbados por fuego, a excepción de Australia. El banco transitorio es aquel formado por semillas que permanecen viables en los horizontes superiores del suelo por no más de 1 año después de la dispersión. En el matorral de Chile central, en los horizontes superiores del suelo, se encuentra una de las densidades de semillas de hierbas más altas de las regiones mediterráneas. Una gran proporción de esta reserva está constituida por semillas sin latencia, fácilmente germinables, especialmente pastos anuales que germinan en otoño. Con respecto a los mecanismos de latencia de las semillas del banco transitorio responsables del almacenamiento de las semillas en el suelo, nuestra revisión bibliográfica reveló los siguientes principales síndromes de germinación: (1 especies con semillas que deben ser estratificadas en frío debido a la presencia de latencia fisiológica (principalmente hierbas introducidas; (2 especies con semillas que deben ser escarificadas con ácidos o procedimientos mecánicos debido a la presencia de latencia física (principalmente especies leñosas nativas; (3 especies con latencia fisiológica que necesitan de estratificación cálida para activar la germinación (hierbas nativas e introducidas. Estos síndromes provocan que la época de germinación en Chile central esté situada entre otoño e inicio de la primavera. Además, no hay referencias sobre la presencia de algún síndrome esporádico de germinación para los componentes de un banco de semillas permanente. Proponemos

  8. Regional ceramic production and distribution systems during the late intermediate ceramic period in central Chile based on NAA

    This research focused on the pre-Hispanic ceramic production and distribution systems of the Maipo region in central Chile by means of determining the concentration of the chemical elements in pottery of the Aconcagua culture (900-1450 A.D.) with instrumental neutron activation analysis (INAA). Pottery fragments from eight archaeological sites and natural clays from the study region were included. The differences in chemical composition between subsets of the sample (sites, paste group and ceramic type) were interpreted as indicators of resource and ceramic production locations as well as the imprint of the geological background. These results contributed to the understanding of the Aconcagua ceramic assemblage and helped to test some hypotheses about the Aconcagua social organization. (author)

  9. Osseous skeletal material and fish scales in marine sediments under the oxygen minimum zone off northern and central Chile

    Milessi, Andrés C.; Sellanes, Javier; Gallardo, Víctor A.; Lange, Carina B.


    The significance of whale falls for the study of the biogeography, evolution and biodiversity of deep-sea biota has been recently recognized by international programs since large carcasses are known to give rise to biogenic chemosynthetic ecosystems. However, the plain accumulation of smaller bone material in the shallower settings of the continental shelf and upper slope under the hypoxic conditions of the Oxygen Minimum Zone (OMZ), has received much less attention. Here we describe new findings of skeletal material and fish scales in marine sediments under the OMZ off northern and central Chile which, combined with previous reports for the study area, lead us to suggest the existence of a band in the benthos of accumulation of bones and scales extending at least twenty degrees in latitude (18-38° S). Future studies should focus on the characterization of biotic communities living upon these resources in order to elucidate their peculiarities and importance in the Eastern South Pacific.

  10. First radiometric age (U-Pb, LA-ICP-MS, on detrital zircons) from the Punta Topocalma Formation: insights on Late Cretaceous marine deposition in central Chile

    Upper Cretaceous marine rocks crop out along the Pacific coast of central and south-central Chile between 33o and 37oS. These strata constitute an important reference for the Upper Cretaceous of South America due to their diverse fossil fauna and flora. The type unit of these deposits is the Quiriquina Formation, near Concepcion. This unit is considered Maastrichtian in age based on ammonites. Upper Cretaceous marine strata from other localities of central and south-central Chile are largely unstudied and their biostratigraphic ages are not precisely known. We present the first radiometric dating (U-Pb on detrital zircons) for Upper Cretaceous marine strata of the Chilean forearc at Punta Topocalma that indicates a probable depositional age of 71.9+0.9 Ma (latest Campanian-earliest Maastrichtian). Provenance analysis indicates that the source of sediments of the Punta Topocalma Formation was plutonic and volcano-sedimentary rocks from the Coastal Cordillera and the Central Depression of central Chile. The Lo Valle Formation, a volcano-sedimentary unit in the Central Depression, recorded deposition of the Upper Cretaceous volcanic arc that was coeval with marine sedimentation in the Topocalma area

  11. Multiproxy approach revealing climate and cultural changes during the last 26kyrs in south-central Chile

    Abarzua, Ana M.; Jarpa, Leonora; Martel, Alejandra; Vega, Rodrigo; Pino, Mario


    Multiproxy approach from Purén Lumaco Valley (38°S) describes the paleonvironmental history during the Last Maximum Glacial (LGM) in south-central Chile. Three sediment cores and severals AMS 14C dates were used to perform a complete pollen, diatoms, chironomids, and sedimentological records demonstrating the existence of a large and non profundal paleolake, between 25 and 20kyr BP. Some of these evidence are laminated silty-clay sediments (lacustrine rhythmites), associated with the presence of siderite mineral (FeCO3), besides biological proxies like Fragilaria construens and Stauroforma inermes (planctonic diatoms), and Dicrotendipes sp. and Tanytarsini tribe (littoral chironomids). The pollen ensemble reveals the first glacial refuge of Araucaria araucana forests in the low lands during the LGM. The lake was drained abruptly into a swamp/bog at 12kyr BP and colonized by Myrtaceae wet forest. This evidence suggest the dry/warm climate period of early Holocene in south-central Chile. Later, the sediments indicate variable lacustrine levels, and increase of charcoal particles, associated to current climatic conditions. The pollen spectrum dominated by Myrtaceae and Nothofagus contrasts with a strongly disturb current landscape. Actually, Purén-Lumaco valley constitutes a complex peat-bog system dominated by exotic grasses and forest species (Tritricum aestivum, Pinus radiata and Eucalyptus spp.). Some archaeological antecedents in the area document the human development at ca. 7yrs BP. The greatest archaeological characteristic present in the valley is the kuel, a Mapuche earth accumulation. The presence and extension of almost 300 kuel in the valley reflect the social/economic development, and partly explains why the region was the major resistance area for Spanish colonizer during XVI-XVII centuries. Also the archaeological findings reveal the presence of maize pollen (Zea mays) within their food consumption. The influence of climate and human impact in

  12. A study of the energy balance and melt regime on Juncal Norte Glacier, semi-arid Andes of central Chile, using melt models of different complexity

    Pellicciotti, Francesca; Helbing, Jakob; Rivera, Andrés; Favier, Vincent; Corripio, Javier; Araos, José; Sicart, Jean-Emmanuel; Carenzo, Marco


    We use meteorological data from two automatic weather stations (AWS) on Juncal Norte Glacier, central Chile, to investigate the glacier-climate interaction and to test ablation models of different complexity. The semi-arid Central Andes are characterized by dry summers, with precipitation close to zero, low relative humidity and intense solar radiation. We show that katabatic forcing is dominant both on the glacier tongue and in the fore field, and that low humidity and absence of clouds caus...

  13. The lower cretaceous volcanism in the coastal range of Central Chile: Geochronology and isotopic geochemistry

    Major factors involved in subduction zone magmatism are related to the melting of the underlying mantle, which can contain a component of aqueous fluid and/or melts derived from the subducting plate (e.g. Peate et al., 1997). The Chilean Pacific margin is a subduction zone, active from Early Mesozoic to now, in which the magmatic arc emplaced on the Paleozoic basement progressively migrate to the east. The western part of this arc constitutes the Coastal Range. In this work, isotopic and radiometric data from four E-W profiles along c. 500 km of the Lower Cretaceous volcanic rocks in the Coastal Range of Chile are presented. The aim of this research is to obtain a model for the genesis of this Cretaceous volcanic arc based on their isotopic signature (au)

  14. Characterization of backyard poultry production systems and disease risk in the central zone of Chile.

    Hamilton-West, C; Rojas, H; Pinto, J; Orozco, J; Hervé-Claude, L P; Urcelay, S


    Backyard poultry production systems (BPS) are an important and widespread form of poultry production. There is a common perception that biosecurity standards in BPS are generally poor and BPS are usually associated with animal diseases and zoonoses. In this study BPS were identified in the vicinity of six wetlands, having these a higher risk of presenting and introducing avian diseases such as HPAI and Newcastle disease, as defined by the national veterinary services, in to Chile's main poultry production area. BPS were characterized through a field questionnaire and the main areas covered by the survey were BPS structure, biosecurity and value chain. The BPS identified in this study share most characteristics on biosecurity, poultry management and product commercialization, but it was possible to identify a certain degree of variation within and among the study sites. BPS in Chile are similar to those in other regions, with a relatively small flock size (average 37 birds), a low level of biosecurity measures and lack of poultry disease management. Management findings include that most farmers used mixed/partial confinement, with low or no biosecurity and disease control measures in place. Eggs were the main output and were used mainly for home consumption or sale at local markets. Sick birds' treatment with drugs approved for other species or for human use could represent a risk to human health, owing to the possible presence of drug residues in poultry products. Despite the different structures of the poultry sector worldwide, BPS can play a major role in disease maintenance and spread because its management conditions characteristics and the lack of animal health services adapted to these production systems. This should be an alert message to the veterinary authorities to improve coverage of veterinary assistance and surveillance activities in backyard poultry production. PMID:21752410

  15. Altitudinal vegetation belts in the high-Andes of central Chile (33°S Pisos altitudinales de vegetación en los Andes de Chile central (33°S

    Lohengrin A. Cavieres


    Full Text Available The limits of alpine vegetation belts have been established mainly based on physiognomic criteria. However, a more objective approach for fixing limits of vegetation belts are methods based on species composition and relative abundance of each species. While these methods are more time consuming, they are more detailed and permit the detection of physical factors affecting the limits of vegetation belts. In this paper we: 1 describe the altitudinal changes of vegetation above timberline, 2 compare vegetation belts defined with physiognomy and two floristic methods (a qualitative one based on altitudinal changes in species composition, and a quantitative one based on changes in dominant species; and 3 detect some environmental factors responsible for the altitudinal distribution of alpine vegetation between 2100 and 3700 masl in the Andes of Santiago, central Chile (33°S. There was a complete agreement between the different methods in delimiting the subalpine belt. However, in the lower alpine belt (the cushion's belt floristic methods subdivided it in 2-3 sub-belts. In the floristic methods, elevations 3500-3700 that formed the higher alpine belt segregated in separate ways because they have no species in common. Physiognomic descriptions lose relevant information about species distribution, especially at higher elevations. Mean annual temperature and nitrogen content of soil are the main environmental factors affecting the altitudinal limits of vegetation belts in the central Chilean AndesLa delimitación de los pisos altitudinales de vegetación andina se ha basado principalmente en criterios fisionómicos. Sin embargo, un criterio más objetivo para la delimitación es usar métodos basados en la composición y abundancia relativa de las especies presentes. Mientras estos métodos requieren de un mayor esfuerzo de muestreo, son más detallados y permiten detectar factores físicos involucrados en la delimitación altitudinal de la vegetaci

  16. Reconstruction of cryospheric changes in the Maipo and Juncal river basins, central Andes of Chile: an integrative geomorphological approach

    Nussbaumer, Samuel U.; García, Juan L.; Gómez, Gabriel; Vega, Rodrigo M.; Gärtner-Roer, Isabelle; Salzmann, Nadine


    Water in the central Andes (32-38° S), a semi-arid mountainous area with elevations over 6000 m asl., is of great importance and a critical resource especially in the dry summer months. Ice bodies, such as glaciers and rock glaciers (permafrost) in the high mountains, provide a substantial part of the fresh-water resources but also for intensive economical use for the lowlands including Santiago metropolitan region, Chile. However the evolution of these ice bodies since the last deglaciation (i.e., Holocene, last ˜12,000 years), and in particular during historical times, and their feedback with climate is fairly unknown. In view of projected climate change, this is striking because it is also unknown whether these natural resources could be used as sustainable fresh-water source in the future. Within the presented project, we develop and apply an integrative geomorphologic approach to study glaciers and their long-term evolution in the central Andes of Chile. Apart from glaciers (with variable debris-coverage), rock glaciers have evolved over time as striking geomorphological landforms in this area. We combine geomorphologic mapping using remote-sensing and in-situ data with an innovative surface exposure dating technique to determine the ages of distinct moraine ridges at three study sites in watersheds of the Santiago region: Juncal Norte, Loma Larga and Nieves Negras glaciers. First results of the project are presented, including a detailed geomorphological mapping and first analysis of the landform dynamics. At all three sites, we distinguished at least three moraine systems of a Holocene putative age. These prominent moraine belts show that glaciers were at least 5 km longer than at present. Deglaciation from these ice marginal positions was gradual and complex in response to the detrital cover on the glaciers. Differences in ice thickness of the main glaciers in the respective valleys amount to about 100 m. Due to the partial, extensive debris coverage, the

  17. Conducta de forrajeo del gastrópodo Acanthina monodon Pallas, 1774 (Gastropoda: Muricidae en el intermareal rocoso de Chile central Foraging behavior of the gastropod Acanthina monodon Pallas, 1774 (Gastropoda: Muricidae in the intertidal rocky shores of central Chile



    Full Text Available En el presente trabajo investigamos aspectos de la ecología y conducta de forrajeo de Acanthina monodon, un gastrópodo murícido que habita en el intermareal rocoso de Chile central. En terreno, estudiamos las variaciones temporales en su distribución, densidad y dieta. En el laboratorio, cuantificamos la tasa de consumo, las preferencias alimentarias, el tiempo de ingestión y la rentabilidad energética obtenida con distintos tipos de presas mediante experimentos y registros en video. Las mayores densidades de individuos de A. monodon fueron observadas en la franja intermareal cercana al nivel cero de marea. En terreno, A. monodon realiza sus actividades de forrajeo principalmente durante la noche y su dieta consistió principalmente de mitílidos (95 % y cirripedios (5 %. La composición de la dieta de A. monodon en terreno presentó variaciones temporales las cuales dependerían principalmente de cambios en la oferta de los distintos tipos de mitílidos presentes en terreno durante los dos años de muestreo. En el laboratorio, los individuos de Acanthina presentaron preferencias alimentarias significativas por el mitílido Semimytilus algosus. En general, A. monodon bajo condiciones de laboratorio presentó una conducta de forrajeo en la cual maximizó la ganancia neta de energía, mediante la selección de las especies y tamaños de presas que le retribuyen la mayor rentabilidad energéticaWe investigated the ecology and foraging behavior of Acanthina monodon, a muricid gastropod that inhabits in the intertidal rocky shores of central Chile. In the field, we studied temporal variation of their spatial distribution, density, and diet composition. While in the laboratory, we quantified the consumption rate, alimentary preferences, ingestion times and energy profitability obtained with different types of prey using experiments and video recording. High densities of A. monodon individuals were observed in the intertidal fringe near at the

  18. Presence of Arctotherium (Carnivora, Ursidae, Tremarctinae in a pre-cultural level of Baño Nuevo-1 cave (Central Patagonia, Chile

    López Mendoza, P.


    Full Text Available The description of an I3 assigned to Arctotherium sp. obtained from the Baño Nuevo-1 site (Central Patagonia, Chile is presented. The finding was recovered from Layer 5 and it is associated to Macrauchenia sp., Lama guanicoe, Felidae, Camelidae, Equidae and Mylodontidae, within a sterile deposit of cultural material, dated between ca. 13.500 and 11.200 BP. Despite the fact that it is only a single specimen, such finding extends the known distribution for the genus in Chile.Se presenta la descripción de un I3 asignado a Arctotherium sp. proveniente del sitio Baño Nuevo-1 (Patagonia Central, Chile. El hallazgo fue realizado en la Capa 5 y está asociado a restos de Macrauchenia sp., Lama guanicoe, Felidae, Camelidae, Equidae y Mylodontidae dentro de un depósito estéril de material cultural, datado entre los ca. 13.500 y 11.200 años AP. Aunque se trata de un único espécimen, amplía el rango de distribución conocido para este género en Chile.

  19. Arc-oblique fault systems: their role in the Cenozoic structural evolution and metallogenesis of the Andes of central Chile

    Piquer, Jose; Berry, Ron F.; Scott, Robert J.; Cooke, David R.


    The evolution of the Main Cordillera of Central Chile is characterized by the formation and subsequent inversion of an intra-arc volcano-tectonic basin. The world's largest porphyry Cu-Mo deposits were emplaced during basin inversion. Statistically, the area is dominated by NE- and NW-striking faults, oblique to the N-striking inverted basin-margin faults and to the axis of Cenozoic magmatism. This structural pattern is interpreted to reflect the architecture of the pre-Andean basement. Stratigraphic correlations, syn-extensional deposits and kinematic criteria on fault surfaces show several arc-oblique structures were active as normal faults at different stages of basin evolution. The geometry of syn-tectonic hydrothermal mineral fibers, in turn, demonstrates that most of these structures were reactivated as strike-slip ± reverse faults during the middle Miocene - early Pliocene. Fault reactivation age is constrained by 40Ar/39Ar dating of hydrothermal minerals deposited during fault slip. The abundance and distribution of these minerals indicates fault-controlled hydrothermal fluid flow was widespread during basin inversion. Fault reactivation occurred under a transpressive regime with E- to ENE-directed shortening, and was concentrated around major plutons and hydrothermal centers. At the margins of the former intra-arc basin, deformation was largely accommodated by reverse faulting, whereas in its central part strike-slip faulting was predominant.

  20. An integrated framework to assess adaptation options to climate change impacts in an irrigated basin in Central North Chile

    Vicuna, S.; Melo, O.; Meza, F. J.; Alvarez, P.; Maureira, F.; Sanchez, A.; Tapia, A.; Cortes, M.; Dale, L. L.


    Future climate conditions could potentially affect water supply and demand on water basins throughout the world but especially on snowmelt-driven agriculture oriented basins that can be found throughout central Chile. Increasing temperature and reducing precipitation will affect both the magnitude and timing of water supply this part of the world. Different adaptation strategies could be implemented to reduce the impacts of such scenarios. Some could be incorporated as planned policies decided at the basin or Water Use Organization levels. Examples include changing large scale irrigation infrastructure (reservoirs and main channels) either physically or its operation. Complementing these strategies it is reasonable to think that at a disaggregated level, farmers would also react (adapt) to these new conditions using a mix of options to either modify their patterns of consumption (irrigation efficiency, crop mix, crop area reduction), increase their ability to access new sources of water (groundwater, water markets) or finally compensate their expected losses (insurance). We present a modeling framework developed to represent these issues using as a case study the Limarí basin located in Central Chile. This basin is a renowned example of how the development of reservoirs and irrigation infrastructure can reduce climate vulnerabilities allowing the economic development of a basin. Farmers in this basin tackle climate variability by adopting different strategies that depend first on the reservoir water volume allocation rule, on the type and size of investment they have at their farms and finally their potential access to water markets and other water supplies options. The framework developed can be used to study these strategies under current and future climate scenarios. The cornerstone of the framework is an hydrology and water resources model developed on the WEAP platform. This model is able to reproduce the large scale hydrologic features of the basin such as

  1. Characterization of copper-resistant bacteria and bacterial communities from copper-polluted agricultural soils of central Chile

    Altimira Fabiola


    Full Text Available Abstract Background Copper mining has led to Cu pollution in agricultural soils. In this report, the effects of Cu pollution on bacterial communities of agricultural soils from Valparaiso region, central Chile, were studied. Denaturing gradient gel electrophoresis (DGGE of the 16S rRNA genes was used for the characterization of bacterial communities from Cu-polluted and non-polluted soils. Cu-resistant bacterial strains were isolated from Cu-polluted soils and characterized. Results DGGE showed a similar high number of bands and banding pattern of the bacterial communities from Cu-polluted and non-polluted soils. The presence of copA genes encoding the multi-copper oxidase that confers Cu-resistance in bacteria was detected by PCR in metagenomic DNA from the three Cu-polluted soils, but not in the non-polluted soil. The number of Cu-tolerant heterotrophic cultivable bacteria was significantly higher in Cu-polluted soils than in the non-polluted soil. Ninety two Cu-resistant bacterial strains were isolated from three Cu-polluted agricultural soils. Five isolated strains showed high resistance to copper (MIC ranged from 3.1 to 4.7 mM and also resistance to other heavy metals. 16S rRNA gene sequence analyses indicate that these isolates belong to the genera Sphingomonas, Stenotrophomonas and Arthrobacter. The Sphingomonas sp. strains O12, A32 and A55 and Stenotrophomonas sp. C21 possess plasmids containing the Cu-resistance copA genes. Arthrobacter sp. O4 possesses the copA gene, but plasmids were not detected in this strain. The amino acid sequences of CopA from Sphingomonas isolates (O12, A32 and A55, Stenotrophomonas strain (C21 and Arthrobacter strain (O4 are closely related to CopA from Sphingomonas, Stenotrophomonas and Arthrobacter strains, respectively. Conclusions This study suggests that bacterial communities of agricultural soils from central Chile exposed to long-term Cu-pollution have been adapted by acquiring Cu genetic determinants




    Full Text Available Se evaluó la presencia y distribución de los compuestos orgánicos persistentes (COPs en núcleos de sedimentos de los lagos Chica y Grande de San Pedro, Lleu-Lleu e Icalma. Los compuestos fueron extraídos mediante sistema soxhlet con solvente n-hexano, la identificación y cuantificación, de estos, se realizó por cromatografía gaseosa con detector de captura de electrones de 63Ni. Se realizó un análisis estadístico de componentes principales (ACP y Correlación de Pearson. Los plaguicidas identificados en los sedimentos fueron: a-HCH, g-HCH, Heptacloro, Aldrin, Endrin, pp´-DDT, pp'-DDE y pp'-DDD. Los resultados indican variaciones en la distribución y concentración de los COPs, al comparar los lagos urbanos con los lagos prístinos. Destaca la presencia de pp'-DDE (rango: b.n.d- 1.68 ng g-1 peso seco y pp'-DDT (rango: b.n.d- 0.89 ng g-1 peso seco en tres de los cuatro cuerpos de agua analizados. El análisis estadístico identificó correlaciones significativas entre el pp'-DDE y pp'-DDD. No se detectaron correlaciones entre el pp'-DDT y sus metabolitos. El ACP permitió agrupar algunos compuestos orgánicos en función de sus concentraciones y degradación a través del tiempo. Se concluye que Laguna Chica de San Pedro presentó las concentraciones más altas de COPs, las cuales son bajas al ser comparadas con concentraciones detectadas en áreas limpias del Sur de ChileWe have measured concentrations and distribution of Persistent Organic Compounds (POC in sediment cores from four Chilean lakes: Laguna Chica de San Pedro, Laguna Grande de San Pedro, Lleu-lleu, and Icalma. The organochlorine compounds were extracted with n-hexane in a soxhlet system and then identified and quantified by gas chromatography using a 63 Ni Electron Capture Detector. Statistical analyses were performed using a Principal Components Analysis (PCA and the Pearson Correlation. The following pesticides were identified in the sediments: a-HCH, Lindane

  3. Adaptation and Genotype x Environment Interaction of Flaxseed (Linum usitatissimum L. Genotypes in South Central Chile Adaptación e Interacción Genotipo x Ambiente en Lino (Linum usitatissimum L. en la Zona Centro Sur de Chile

    Marisol Berti


    Full Text Available Flaxseed (Linum usitatissimum L. is imported into Chile mostly for bread making and feed. Identification of genotypes best adapted for seed production in South Central Chile would facilitate producer’s decision. The objective of this study was to determine the adaptation and genotype x environment interaction of 16 flaxseed genotypes (including 10 from North American and six from Argentine sources grown at 11 environments (defined as location-year in Chile from 2003 to 2007. Genotype seed yield was above 5700 kg ha-1 for some environments indicating a high yield potential. According to the AMMI (Additive Main Effects and Multiplicative Interaction and SREG (Sites regression models the 11 environments were classified into four groups by the AMMI and three groups by the SREG models. Genotypes were classified into five groups by the SREG model with four of the groups as single genotypes. Overall mean seed yield was similar for all genotypes; however the genotype Nekoma was the most stable and higher yielding genotype across environments. The environment with the highest yield potential was Chillán 2003-2004, but this location had low yield stability across years. The environments with greatest seed yield potential, Chillán 2003-2004 and Los Ángeles 2004-2005, had irrigation during flowering and seed filling. Seed oil content fluctuated between 420 and 530 g kg-1. The climatic differences among environments did not influence oil composition as expected from previous research. Flaxseed appears adapted to South Central Chile with differences observed among genotypes for biomass and seed yield, harvest index, test weight, oil content, and composition.La semilla de lino (Linum usitatissimum L. se importa a Chile principalmente para panaderías y alimento animal. La identificación de genotipos altamente productivos en la zona Centro Sur de Chile facilitaría la decisión de los productores. El objetivo de este estudio fue determinar la adaptaci

  4. Pluri-decadal (1955–2014) evolution of glacier–rock glacier transitional landforms in the central Andes of Chile (30–33° S)

    Monnier, S.; C. Kinnard


    This study deals with relationships between debris-covered glaciers and rock glaciers in the central Andes of Chile. Three glacier–rock glacier transitional landforms are investigated over the last decades in order to highlight and question the significance of their landscape evolution and dynamics. We use series of historical air photos and Geoeye satellite images together with common remote sensing operations including imagery orthorectification, digital elevation model generation, an...

  5. Food web and fish stock changes in central Chile: comparing the roles of jumbo squid (Dosidicus gigas) predation, the environment, and fisheries

    Neira, Sergio; Arancibia, Hugo


    We analyzed recent food web and fish stock changes in the central Chile marine ecosystem, comparing the roles of jumbo squid (Dosidicus gigas) as predator, the environment, and fishing. To accomplish this we used food web modeling and the Ecopath with Ecosim software (EwE). The principal fish stocks have experienced wide decadal fluctuations in the past 30 years, including stock collapses of horse mackerel (Trachurus murphyi) and hake (Merluccius gayi), and there was a large influx of jumbo squid during the mid-2000s. We used two EwE models representing the food web off central Chile to test the hypothesis that predation by jumbo squid has been significant in explaining the dynamics of the main fishing resources and other species in the study area. Results indicate that predation by jumbo squid on fish stocks is lower than that of other predators (e.g. hake) and the fishery. Long-term fluctuations (1978-2004) in the biomass of the main fish stocks (as well as other components of the food web) seem to be related to fishing and to variation in primary production, rather than to predation by jumbo squid alone. Jumbo squid seems to play a role as predator rather than prey in the system, but its impacts are low when compared with the impacts of other predators and fishing. Therefore, we conclude that jumbo squid predation on its prey was not the primary force behind the collapse of important fish stocks off central Chile. Future efforts should be directed to better understanding factors that trigger sudden increases in jumbo squid abundance off central Chile, as well as modeling its trophic impacts.

  6. Community response of zooplankton to oceanographic changes (2002-2012) in the central/southern upwelling system of Chile

    Medellín-Mora, Johanna; Escribano, Ruben; Schneider, Wolfgang


    A 10-year time series (2002-2012) at Station 18 off central/southern Chile allowed us to study variations in zooplankton along with interannual variability and trends in oceanographic conditions. We used an automated analysis program (ZooImage) to assess changes in the mesozooplankton size structure and the composition of the taxa throughout the entire community. Oceanographic conditions changed over the decade: the water column became less stratified, more saline, and colder; the mixed layer deepened; and the oxygen minimum zone became shallower during the second half of the time series (2008-2012) in comparison with the first period (2002-2007). Both the size structure and composition of the zooplankton were significantly associated with oceanographic changes. Taxonomic and size diversity of the zooplankton community increased to the more recent period. For the second period, small sized copepods (1.5 mm) and medium size copepods (1-1.5 mm), whereas euphausiids, decapod larvae, appendicularian and ostracods increased their abundance during the second period. These findings indicated that the zooplankton community structure in this eastern boundary ecosystem was strongly influenced by variability of the upwelling process. Thus, climate-induced forcing of upwelling trends can alter the zooplankton community in this highly productive region with potential consequences for the ecosystem food web.

  7. Heterogeneity of farms entering export supply chains: the case of fruit growers from central-south Chile

    J. A. Barrena Ruiz


    Full Text Available The increasing stringency of world food markets requires farmers to adjust farm structure and commercial strategies to remain integrated in export supply chains. The goal of this study was to identify and characterize different types of fresh fruit farms with regard to farm structural and commercial strategies for a representative sample of fresh fruit growers from central-south Chile exporting to world markets. A typology of farms was constructed based on multivariate analysis, according to which five types of farms were differentiated from five distinct factors. Cluster I comprised the smallest and uncertified farms (14.3% of the sample. The remaining four clusters comprised certified farms, but with different farm structural and commercial characteristics. Cluster II (15.1% was composed of farms located further from market connections. Cluster III (23.9% comprised farms with the highest number of fruit species, and consequently, more diversified in fruit production. Cluster IV (8.8% was the smallest group, and comprised the largest firms. Finally, Cluster V (37.8% was composed of highly specialized fruit farms, with the highest proportion of hectares dedicated to the production of a single fruit species. The results show the heterogeneity among fresh fruit farms and support the need for differentiated incentives and technological transfer schemes from the public sector and fruit companies in order to successfully keep farmers within export supply chains.

  8. Tropical/subtropical Upper Paleocene Lower Eocene fluvial deposits in eastern central Patagonia, Chile (46°45'S)

    Suárez, M.; de la Cruz, R.; Troncoso, A.


    A succession of quartz-rich fluvial sandstones and siltstones derived from a mainly rhyolitic source and minor metamorphic rocks, located to the west, represent the first Upper Paleocene-Early Eocene deposits described in Chilean eastern central Patagonian Cordillera (46°45'S). This unit, exposed 25 km south of Chile Chico, south of lago General Carrera, is here defined as the Ligorio Márquez Formation. It overlies with an angular unconformity Lower Cretaceous shallow marine sedimentary rocks (Cerro Colorado Formation) and subaerial tuffs that have yielded K-Ar dates of 128, 125 and 123 Ma (Flamencos Tuffs, of the Divisadero Group). The Ligorio Márquez Formation includes flora indicative of a tropical/subtropical climate, and its deposition took place during the initial part of the Late Paleocene-Early Eocene Cenozoic optimum. The underlying Lower Cretaceous units exhibit folding and faulting, implying a pre-Paleocene-Lower Eocene contractional tectonism. Overlying Oligocene-Miocene marine and continental facies in the same area exhibit thrusts and normal faults indicative of post-Lower Miocene contractional tectonism.

  9. Interannual variations in the hatching pattern, larval growth and otolith size of a sand-dwelling fish from central Chile

    Rodríguez-Valentino, Camilo; Landaeta, Mauricio F.; Castillo-Hidalgo, Gissella; Bustos, Claudia A.; Plaza, Guido; Ojeda, F. Patricio


    The interannual variation (2010-2013) of larval abundance, growth and hatching patterns of the Chilean sand stargazer Sindoscopus australis (Pisces: Dactyloscopidae) was investigated through otolith microstructure analysis from samples collected nearshore (<500 m from shore) during austral late winter-early spring off El Quisco bay, central Chile. In the studied period, the abundance of larval stages in the plankton samples varied from 2.2 to 259.3 ind. 1000 m-3; larval abundance was similar between 2010 and 2011, and between 2012 and 2013, but increased significantly from 2011 to 2012. The estimated growth rates increased twice, from 0.09 to 0.21 mm day-1, between 2011 and 2013. Additionally, otolith size (radius, perimeter and area), related to body length of larvae, significantly decreased from 2010 to 2012, but increases significantly in 2013. Although the mean values of microincrement widths of sagitta otoliths were similar between 2010 and 2011 (around 0.6-0.7 μm), the interindividual variability increases in 2011 and 2013, suggesting large environmental variability experienced by larvae during these years. Finally, the hatching pattern of S. australis changed significantly from semi-lunar to lunar cycle after 2012.

  10. Large scale hydrogen production from wind energy in the Magallanes area for consumption in the central zone of Chile

    The energy proposal of this research suggests the use of places with abundant wind resources for the production of H2 on a large scale to be transported and used in the central zone of Chile with the purpose of diversifying the country's energy matrix in order to decrease its dependence on fossil fuels, increase its autonomy, and cover the future increases in energy demand. This research showed that the load factor of the proposed wind park reaches a value of 54.5%, putting in evidence the excellent wind conditions of the zone. This implies that the cost of the electricity produced by the wind park located in the Chilean Patagonia would have a cost of 0.0213 US$ kWh-1 in the year 2030. The low prices of the electricity obtained from the park, thanks to the economy of scale and the huge wind potential, represent a very attractive scenario for the production of H2 in the future. The study concludes that by the year 2030 the cost of the H2 generated in Magallanes and transported to the port of Quinteros would be 18.36 US$ MBTU-1, while by that time the cost of oil would be about 17.241 US$ MBTU-1, a situation that places H2 in a very competitive position as a fuel. (author)

  11. Breeding distribution and abundance of seabirds on islands off north-central Chile Distribución reproductiva y abundancia de aves marinas en islas del norte y centro de Chile



    Between 1999 and 2003 we collected information on the breeding distribution and abundance of 12 seabird species occurring on nine islands off the coasts of north and central Chile (27°-33°S). The Peruvian booby Sula variegata was the most abundant seabird with a breeding population of ca. 18,000 pairs concentrated in two islands, followed by the Humboldt penguin Spheniscus humboldti with ca. 9,000 pairs, the largest colony being at Chañaral Island with ca. 7,000 pairs. Kelp gulls Larus domini...

  12. Adaptation to climate changes on a multipurpose hydrosystem in South-Central Chile with explicit regard of model uncertainty

    Ayala; McPhee, J. P.


    Decision-making in the agricultural and hydropower sectors can benefit from water resources availability projections that take into account uncertainty in a meaningful way. In this work we use statistically downscaled projections of 12 general circulation models under 3 emissions scenarios to drive a hydrologic-operational model of the upper Laja river basin in south-central Chile. The Laja hydrosystem is characterized by a large natural reservoir of 5600 Hm3 that is used for agricultural purposes in the lower basin and as the cornerstone of hydroelectric supply for the entire central Chilean electric system. The upper Laja river basin is snowmelt driven so water resources are very sensitive to both precipitation and temperature. Using each future projected series as an independent observation, empirical probability distributions are calculated for hydro-meteorological and operational variables such as reservoir levels and energy production. By the end of the 21st century, the mean value of projections shows a temperature increase of 2C, a precipitation decrease of 20%, and a decrease close to 25% in runoff due to evapotranspiration effects. A runoff-precipitation-temperature relation shows that the evaporation is most important in wet conditions because of the higher levels of water availability on surface and superior layers of soil. Operational results show a decrease of reservoir levels coupled with diminishing energy output, which suggests that the current operational policy is inappropriate for ensuring adaptation to climate change. Differences among GCMs clearly increase trough the analysis period resulting in a greater uncertainty in the magnitude of changes by the end of the 21st century. Almost all models and scenarios agree about the general trends of the estimated variables. Nevertheless, for climate change applications, the considerable magnitude differences between projections suggest the use of many models instead of a particular one or, in lieu if

  13. Evidence of proterozoic crust under the coastal Cordillera of Central Chile: Grenville age xenocrystic zircons in cretaceous volcanic rocks

    In the central Andes, Proterozoic basement rocks outcrop in isolated areas from beneath a Mesozoic and Cenozoic cover in southern Peru, northernmost Chile, Bolivia, and in northwestern Argentina. Their role in Andean magmatism and metallogenesis is well documented. In the southern Central Andes, Proterozoic rocks are so far known to outcrop in Argentina, east of the continental divide. In the course of U-Pb dating of the bimodal volcanic and sub-volcanic host rocks for Mesozoic manto-type copper deposits, we have encountered xenocrystic zircon with Proterozoic and Paleozoic ages. In the Punta del Cobre Cu-Fe (Au) District (27o30' S / 70o15' W) 22 km south of Copiapo xenocrystic zircon in the Lower Cretaceous host dacite yields ca. 1 Ga ages. In the El Soldado Cu District, (32o38' S /71o04' W), 120 km northwest of Santiago, scarce and strongly resorbed zircon crystals in the Lower Cretaceous host rhyodacite yield ages of 0.5 to 1.3 Ga. The early Cretaceous bimodal volcanic and subvolcanic rocks, which consists of primitive calc-alkaline basalts and rhyodacites, display geochemical evidence of crustal contamination. Our results suggest that, during their formation and ascent, the felsic magmas picked up zircons in the Proterozoic and Paleozoic crystalline basement of the Coastal Cordillera. The presence of Proterozoic (Grenville age) basement underlying localities as close as 30 km from the Pacific coast has implications for the extent and age of the Chilenia Terrane and gives further credence to correlation models that juxtapose eastern North America (Laurentia) and southwestern South America (Gondwana) during the Late Proterozoic (au)

  14. Vertebrados terrestres de la Reserva Nacional Río Clarillo, Chile central: representatividad y conservación Terrestrial vertebrates of the Río Clarillo National Reserve, central Chile: representation and conservation



    Full Text Available Analizamos la representatividad, distribución y perspectivas de conservación de los vertebrados terrestres de la Reserva Nacional Río Clarillo, Chile central. Mediante recorridos periódicos realizados entre 1987 y 1996, determinamos la riqueza y distribución altitudinal de los vertebrados terrestres en esta Reserva. Registramos 127 especies (22 mamíferos, 85 aves, 15 reptiles y cinco anfibios, que representan el 69 % del total de especies que por su distribución geográfica y tipo de hábitat podrían habitar este lugar. De éstas, 32 especies (25 % están catalogadas con problemas de conservación. La riqueza de vertebrados decrece con la altitud, desde 101 especies a los 870 m hasta ocho especies a los 3.050 m. La riqueza de vertebrados se concentró bajo los 1.600 m, albergando 109 especies, 55 de las cuales no se registraron a mayor altitud. En cambio, sobre los 1.600 m se registraron 57 especies. Paradójicamente sólo el 31 % de la superficie de la Reserva está bajo los 1.600 m. Nuestros resultados sugieren que la superficie de la Reserva no es suficiente para albergar poblaciones viables de la mayoría de los vertebrados registrados. Alrededor de la Reserva existen propiedades privadas con grandes extensiones de bosques esclerófilos bajo los 1.600 m, los cuales podrían actuar como fuentes y la Reserva como sumidero de vertebrados. Por lo tanto, sugerimos desarrollar estrategias de conservación en estas áreas y realizar monitoreos para determinar si las poblaciones de vertebrados mas sensibles están aumentando o disminuyendo, tanto dentro como fuera de la ReservaWe analyzed the representation, distribution and conservation perspectives of terrestrial vertebrates in the Río Clarillo National Reserve, central Chile. During periodical surveys conducted between 1987 and 1996, we determined the composition and altitudinal distribution of the terrestrial vertebrates in this Reserve. We recorded 127 species (22 mammals, 85 birds, 15

  15. Supervivencia adulta y dinámica poblacional del lauchón orejudo Phyllotis darwini en Chile central Adult survival and population dynamics in the leaf-eared mouse Phyllotis darwini in central Chile

    Laurent Crespin


    Full Text Available A nivel demográfico, los resultados clásicos de los modelos matriciales separan a las especies de tiempo generacional corto de las especies de tiempo generacional largo en cuanto a la importancia de la supervivencia adulta para la dinámica poblacional. Específicamente, la supervivencia adulta no debería contribuir de manera importante en la tasa de cambio poblacional de especies de tiempo generacional corto. Sin embargo, Yoccoz et al. (1998, Research Population Ecology 40: 107-121 propusieron que la supervivencia adulta sería el parámetro demográfico más importante para determinar la tasa de cambio poblacional en pequeños roedores cuando se toma en consideración una escala de tiempo mensual. Con el fin de poner a prueba esta hipótesis en este trabajo, utilizamos cinco años de datos de captura-marcaje-recaptura para estimar la supervivencia y la maduración de las hembras del lauchón orejudo, Phyllotis darwini, en una localidad de Chile central. El análisis mostró que las probabilidades de supervivencia disminuían con el promedio anual de la cantidad de lluvia y que las probabilidades de maduración disminuían con la densidad poblacional. Basados en las probabilidades de supervivencia y maduración, construimos un modelo matricial estacional para medir la importancia relativa de cada parámetro demográfico en el ciclo de vida de la especie a través de un análisis de perturbación. A fin de reflejar la variabilidad estacional del ambiente, dos estaciones fueron incorporadas en el modelo matricial: una estación de lluvia de cinco meses y una estación seca. Se observó que la supervivencia adulta era en efecto el parámetro demográfico con la elasticidad más fuerte. Por lo tanto, estos resultados apoyan la hipótesis de Yoccoz et al. (1998Classic results of matrix models predict that, in species with a long generation time, adult survival should be the demographic parameter driving population dynamics whereas, in species

  16. Hábitos tróficos de la reineta Brama australis (Pisces: Bramidae) durante el periodo estival frente a Chile central

    Francisco Santa Cruz; Ciro Oyarzún; Gustavo Aedo; Patricio Gálvez


    La reineta Brama australis es un importante recurso pesquero artesanal en la zona central chilena, incorporado en los programas de seguimiento biológico, pero con escasas evaluaciones de sus aspectos tróficos. Para actualizar el estado del conocimiento, se analizó su dieta durante el verano austral época de mayor disponibilidad de este recurso en la zona central de Chile, mediante el análisis del contenido gástrico de 300 ejemplares capturados entre noviembre 2011 y marzo 2012. Se identificó ...

  17. The relation of the mid-Tertiary coastal magmatic belt in south-central Chile to the late Oligocene increase in plate convergence rate

    Jorge Muñoz; Rosa Troncoso; Paul Duhart; Pedro Crignola; Lang Farmer; Charles R. Stern


    The mid-Tertiary Coastal Magmatic Belt in south-central Chile, which crops out both in the Central Valley and, south of 41°S, in the Coastal Cordillera as far west as the Pacific coast, formed when the locus of Andean magmatic activity expanded, both to the west and to the east relative to its previous and current location in the Main Cordillera. This expansion of the magmatic arc occurred in conjunction with a regionally widespread episode of late Oligocene to Miocene extension which thinned...

  18. Corrales de piedra-pirkas- un patrimonio cultural del paisaje rural de Chile central

    Tomic Jakas, Tonci Stipe


    Quisiéramos partir con este soliloquio, quizás el más famoso del drama español; ocurre al final del primer acto, cuando Segismundo piensa en la vida y en su suerte. No es el fatalismo lo que interesa si no que desde el inicio explicitar que se trata de una reflexión que lleva a configurar un visión –algo que anida en la mente-- que su fin central radica es tratar de poner en valor sobre la base de la importancia histórica, cultural y patrimonial de los muros de piedra o pirkas; en particular ...

  19. Paleowetlands and regional climate change in the central Atacama Desert, northern Chile

    Quade, Jay; Rech, Jason A.; Betancourt, Julio L.; Latorre, Claudio; Quade, Barbra; Rylander, Kate Aasen; Fisher, Timothy


    Widespread, organic-rich diatomaceous deposits are evidence for formerly wetter times along the margins of the central Atacama Desert, one of the driest places on Earth today. We mapped and dated these paleowetland deposits at three presently waterless locations near Salar de Punta Negra (24.5°S) on the western slope of the Andes. Elevated groundwater levels supported phreatic discharge into wetlands during two periods: 15,900 to ~ 13,800 and 12,700 to ~ 9700 cal yr BP. Dense concentrations of lithic artifacts testify to the presence of paleoindians around the wetlands late in the second wet phase (11,000?-9700 cal yr BP). Water tables dropped below the surface before 15,900 and since 8100 cal yr BP, and briefly between ~ 13,800 and 12,700 cal yr BP. This temporal pattern is repeated, with some slight differences, in rodent middens from the study area, in both paleowetland and rodent midden deposits north and south of the study area, and in lake level fluctuations on the adjacent Bolivian Altiplano. The regional synchroneity of these changes points to a strengthening of the South American Monsoon — which we term the "Central Andean Pluvial Event" — in two distinct intervals (15,900-13,800 and 12,700-9700 cal yr BP), probably induced by steepened SST gradients across the tropical Pacific (i.e., La Niña-like conditions).

  20. Paleowetlands and regional climate change in the central Atacama Desert, northern Chile

    Quade, Jay; Rech, Jason A.; Betancourt, Julio L.; Latorre, Claudio; Quade, Barbra; Rylander, Kate Aasen; Fisher, Timothy


    Widespread, organic-rich diatomaceous deposits are evidence for formerly wetter times along the margins of the central Atacama Desert, one of the driest places on Earth today. We mapped and dated these paleowetland deposits at three presently waterless locations near Salar de Punta Negra (24.5°S) on the western slope of the Andes. Elevated groundwater levels supported phreatic discharge into wetlands during two periods: 15,900 to ~ 13,800 and 12,700 to ~ 9700 cal yr BP. Dense concentrations of lithic artifacts testify to the presence of paleoindians around the wetlands late in the second wet phase (11,000?–9700 cal yr BP). Water tables dropped below the surface before 15,900 and since 8100 cal yr BP, and briefly between ~ 13,800 and 12,700 cal yr BP. This temporal pattern is repeated, with some slight differences, in rodent middens from the study area, in both paleowetland and rodent midden deposits north and south of the study area, and in lake level fluctuations on the adjacent Bolivian Altiplano. The regional synchroneity of these changes points to a strengthening of the South American Monsoon — which we term the "Central Andean Pluvial Event" — in two distinct intervals (15,900–13,800 and 12,700–9700 cal yr BP), probably induced by steepened SST gradients across the tropical Pacific (i.e., La Niña-like conditions).

  1. Volatile Compounds in Honey Produced in the Central Valley of Ñuble Province, Chile Compuestos Volatiles en Miel Producida en el Valle Central de la Provincia de Ñuble, Chile

    María Pía Gianelli Barra


    Full Text Available Headspace solid-phase microextraction (SPME with an 85 µm Carboxen polydimethylsiloxane (CAR/PDMS fiber was used to extract volatile compounds, and a gas chromatograph equipped with a mass spectometry detector (GC-MS was used to identify the volatile compounds in honeys. Thirty-four different volatile compounds from the headspace of honey produced in the central valley of Ñuble Province, Chile, were extracted with fiber coating CAR/PDMS. The identified compounds were: 10 alcohols, 9 acids, 6 ketones, 3 aldehydes, 2 furans, 2 terpenes and 2 lactones. Only four of the volatile compounds had never been reported before as honey compounds; these being: 1,3-propanodiol, 2-methyl butanoic acid, 3,4-dimethyl-3-hexen-2-one, and 6-methyl-5-octen-2-one. These four compounds were found in three of the 10 analyzed samples. The compounds found in the highest percentage of area were ethanol, acetic acid, 1-hydroxy-2-propane, 3-hydroxy-2-butane, and furfural. However, the analyzed samples did not present a distinctive profile.La extracción de compuestos volátiles desde el espacio de cabeza de mieles se realiza mediante microextracción en fase sólida (SPME, utilizando una fibra de 85 µm de Carboxen polidimetilsiloxano (CAR/PDMS, el análisis de los compuestos volátiles se realiza mediante cromatografía de gases con detector de masa (GC-MS. Un total de 34 diferentes compuestos volátiles fueron extraídos desde el espacio de cabeza de mieles provenientes del valle central de la provincia de Ñuble con la fibra de CAR/PDMS. Los compuestos identificados fueron 10 alcoholes, 9 ácidos, 6 cetonas, 3 aldehídos, 2 furanos, 2 terpenos y 2 lactonas. De los compuestos volátiles sólo tres no han sido reportados con anterioridad en mieles, estos compuestos fueron: 1,3-propanodiol, ácido 2-metil butanoico, 3,4-dimetil-3-hexen-2-ona, 6-metil-5-octen-2-ona. Estos cuatro compuestos se encontraron en sólo tres de las 10 muestras analizadas. Los compuestos que se

  2. On the effect of operation of the hydropower plant on the water quality of Rapel reservoir, central Chile

    Rossel, V.; De La Fuente, A.


    Eutrophication of lakes and reservoirs is a common problem in systems with high incoming loads of nutrients. The consequent algae bloom related to the eutrophication alters the water quality and generates an incompatibility with the tourist and recreational activities. This study is focused on Rapel reservoir: an old, dentritic and monomictic reservoir, located in central Chile (34°S, 71.6°W), that has experienced numerous algae bloom events in the past years produced by high loads of nutrients, sediments and metals. This reservoir was originally constructed in 1968 for hydropower generation without environmental restrictions on its operation. Rapel is part of Chile's Central Interconnected System (SIC), and is controlled by an independent system operator (ISO) that decides the optimal allocation of water by minimizing the SIC's operation cost. As a result of this framework, Rapel reservoir operates based on a hydropeaking scheme, thus producing energy few hours a day while zero outflows are observed the remaining hours, impacting on Rapel river located downstream the reservoir. However, previous research showed that this hydropeaking has important effects on the hydrodynamic of the reservoir as well. Particularly, it enhances vertical mixing nears the dam, and reduces horizontal dispersion. Furthermore, hydropeaking defines the outflows water temperature, and the temperature profile near the dam. As a consequence of this role of hydropeaking on the hydrodynamics and mixing of Rapel reservoir, it is expected to be a link between hydropeaking and water quality. The aim of the study is to evaluate the impact of the operation of hydropower plant on the water quality of Rapel reservoir, for which the reservoir system is modeled using the three dimensional hydrodynamic and water quality model ELCOM-CAEDYM. Field data to validate the results and to define boundary and initial conditions are available for the austral summer period of 2009-2010. Different scenarios of

  3. Pyruvate Oxidoreductases Involved in Glycolytic Anaerobic Metabolism of Polychaetes from the Continental Shelf off Central-South Chile

    González, R. R.; Quiñones, R. A.


    The presence of low oxygen conditions in extensive areas of the continental shelf off central-south Chile has important effects on the biochemical adaptations of the organisms living in this ecosystem. Polychaetes assemblages cohabit on the shelf with an extensively distributed prokaryotic community made up of giant filamentous sulfur bacteria (mainly Thioploca sp.). The aim of this research was to characterize the pyruvate oxidoreductases enzymes involved in the biochemical adaptation of these benthic polychaetes. Nine polychaete species ( Paraprionospio pinnata, Nephtys ferruginea, Glycera americana, Haploscoloplos sp., Lumbrineris composita, Sigambra bassi, Aricidea pigmentata , Cossura chilensis, and Pectinaria chilensis) were assayed for lactic dehydrogenase (LDH), octopine dehydrogenase (OPDH), strombine dehydrogenase (STRDH) and alanopine dehydrogenase (ALPDH). Each species had a characteristic number of the pyruvate oxidoreductases assayed ranging from 4 in Paraprionospio pinnata to 1 in Pectinaria chilensis . The pyruvate saturation curves obtained for the enzymes from all species analysed, except L. composita, suggest that NADH can be oxidized at different rates depending on the amino acid used in the reaction with pyruvate. Our results indicate that organisms having more that one pyruvate oxidoreductase present a greater metabolic capacity to cope with functional and environmental hypoxia because these enzymes would better regulate the pyruvate consumption rate during the transition period. Thus, the dominance of Paraprionospio pinnata in the study area and its worldwide distribution is consistent with its higher number of pyruvate oxidoreductases with different pyruvate consumption rates involved in anaerobic metabolism. Finally, a positive allometric relationship was found between body size and the specific activity of ALPDH, STRDH, and maximum pyruvate oxidoreductase specific activity. This latter result suggests a positive scaling of the specific

  4. A time series of prokaryote secondary production in the oxygen minimum zone of the Humboldt current system, off central Chile

    Levipan, H. A.; Quiñones, R. A.; Urrutia, H.


    Because the marine picoplanktonic communities are made up of phylogenetically different microbial groups, the re-evaluation of key processes such as bacterial secondary production (BSP) has become an important contemporary issue. The difficulty of differentiating the metabolic processes of Bacteria from the rest of the microorganisms in the water column (i.e., Archaea and Eukarya) has made it difficult to estimate in situ BSP. This work presents the seasonal variability of the prokaryote secondary production (PSP) measured by the incorporation of 14C-leucine in the oxygen minimum zone (OMZ) off central-southern Chile. The BSP and potential archaeal secondary production (PASP) were determined through the combined use of 14C-leucine and N1-guanyl-1, 7-diaminoheptane (GC 7), an efficient inhibitor of archaeal and eukaryote cell growth. BSP accounted for the majority of the PSP (total average, 59 ± 7.5%); maximum values were ∼600 μg C m -3 h -1 and, on several dates, BSP represented 100% of the PSP. Similarly, PASP was also an important fraction of the PSP (total average, 42.4 ± 8.5%), although with levels that ranged from not detectable (on given dates) to levels that represented up to ∼97% of PSP (winter 2003). Our results showed that both Bacteria and Archaea accounted for almost equal portions of the prokaryote heterotrophic metabolism in the OMZ, and that PASP is notoriously enhanced through temporal pulses of heterotrophy. This indicates that, at least in marine systems with high abundance of Archaea (e.g., mesopelagic realm), the secondary production obtained through methods measuring the uptake of radiolabeled substrates should be considered as PSP and not as BSP. If the latter is the target measurement, then the use of an inhibitor of both archaeal and eukaryote cell growth such as GC 7 is recommended.

  5. Degradation capability of the coastal environment adjacent to the Itata River in central Chile (36.5° S

    P. Ampuero


    Full Text Available The response of the coastal ocean influenced by both river discharges and inputs of photosynthetically derived organic carbon product of upwelling, was evaluated by estimating rates of microbial hydrolysis of macromolecules with the goal of estimating the potential degradation capability of the coastal ecosystem off central Chile. Extracellular enzymatic activity (EEA in seawater was dominated by aminopeptidase activity on substrate L-leucine-4-methyl-7-coumarinylamide (MCA-leu (1.2 to 182 nmol l−1 h−1 followed by 4-methylumbelliferyl-ß-D-glucoside (MUF-glu (0.08–61 nmol l−1 h−1 and 4-methylumbelliferyl-ß-D-cellobiose (MUF-cel (0.15–7 nmol l−1 h−1, with the highest rates measured during spring-summer. In riverine waters, extracellular enzymatic hydrolysis remained within the range of 45 to 131 nmol l−1 h−1 for MCA-leu and ca. 20 nmol l−1 h−1 for glucosidic substrates, year-round. Contrary to the EEA observed for the marine water column, surface sediment extracellular enzymatic hydrolysis of MCA-leu (0.04 to 6.13 nmol g−1 dw h−1 was in the same order of magnitude as the rates observed for MUF-cel (0.004 to 5.1 nmol g−1 dw h−1 and MUF-glu (0.007 to 10.5 nmol g−1 dw h−1. Moreover, hydrolysis in sediments was characterized by higher rates during winter compared with spring-summer in the coastal and estuarine zone. The five years of data allowed us to evaluate the potential capability of microbial processing of organic carbon in the coastal area adjacent to the Itata river discharge where the increase in primary production in the productive seasons is accompanied by the increase in hydrolysis of macromolecules.

  6. Contribution of legumes to the availability of soil nitrogen and its uptake by wheat in Mediterranean environments of central Chile

    Soledad Espinoza


    Full Text Available The absorption and partitioning of N is determined by its availability and demand during the various phenological stages of the crop. In two experiments conducted in rainfed areas of the Mediterranean climate region of central Chile, legume-wheat (Triticum aestivum L. rotations were compared to oat (Avena sativa L.-wheat systems (with and without applications of N fertilizer. The objective was to assess the contribution of legumes to the availability of soil N and N uptake by the wheat crop following grain legumes. N mineralization and uptake, N use efficiency (NUE, and N uptake efficiency (NUpE by wheat were evaluated at different phenological stages in 2010. Synchronization existed between accumulated soil N mineralization and N uptake by the wheat. N uptake by wheat was higher in Experiment II (Andean foothill than in Experiment I (interior dryland. Grain yields after legumes ranged 60-110% and 72-103% of yields in the fertilized cereal rotation (oat-wheat in Experiments I and II, respectively. There was high correlation between soil N availability vs. grain yield (R² = 0.84 and 0.64 and N uptake vs. grain yield (R² = 0.55 and 0.64 for Experiments I and II, respectively. Rotations with lupine (Lupinus spp. and field peas (Pisum sativum L. showed high NUE and NUpE in Experiment I, and Experiment II in pea. The lowest NUE was after oats with N fertilizers. It is concluded that wheat cultivated in both agro-ecological areas after grain legumes or green manure was more efficient in N uptake and use than cereal, especially when the latter was fertilized.


    Karina Neira


    Full Text Available Se analizó la densidad, biomasa, diversidad y riqueza de especies de la macrofauna bentónica (³500 mm en ambientes óxicos (> 0.5 ml L-1 en Bahía Coliumo (36º32`S, 72º57`W, Chile central. En un transecto de cinco estaciones, entre 3,6 y 22,5 m de profundidad, fueron recolectadas muestras de sedimento con una draga tipo Van veen de 0,051 m², a bordo de la embarcación científica L/C Kay-Kay. A partir de las muestras de sedimento se determinó, el porcentaje de materia orgánica total, el tamaño de grano, densidad y biomasa de la macrofauna. Adicionalmente, se tomaron muestras de agua para el análisis de oxígeno disuelto de fondo, temperatura y salinidad. Las densidades de la macrofauna total fluctuaron entre 1111 y 11183 ind m-2. En tanto, los valores de biomasa alcanzaron 9,9 y 252,86 g m-2. Del total de la macrofauna 29 especies fueron identificadas. Los valores más altos de diversidad (3,23 coinciden con los valores más bajos de dominancia y uniformidad. Los parámetros de diversidad no mostraron una relación lineal con la profundidad. Los poliquetos fueron el grupo dominante (51,8%, seguido de los crustáceos (41% y moluscos (6,8%. Adicionalmente, a través del análisis BIOENV, se observó que el porcentaje de arena y el contenido de materia orgánica fueron los principales factores ambientales que regulan la estructura de la macrofauna de Bahía Coliumo.The density, biomass, diversity and species richness of macrofaunal benthic (³500 mm in oxic environment (> 0.5 ml L-1 off Bay Coliumo (36º32`S, 72º57`W, Chile were analyzed. One transect of five stations between 3.6 and 22.5 m of depth were collected samples of sediments with a dredged Van veen of 0.051 m²a board R/V Kay-Kay in August (winter of 2004. From sediment sample the organic matter percent, size of grain, density and biomass of the macrofauna were determined. Additionally, were taken water column samples for analyses of dissolved oxygen of bottom, temperature and

  8. Characterization of the hydrothermal system of the Tinguiririca Volcanic Complex, Central Chile, using structural geology and passive seismic tomography

    Pavez, C.; Tapia, F.; Comte, D.; Gutiérrez, F.; Lira, E.; Charrier, R.; Benavente, O.


    A structural characterization of the hydrothermal-volcanic field associated with the Tinguiririca Volcanic Complex had been performed by combining passive seismic tomography and structural geology. This complex corresponds to a 20 km long succession of N25°E oriented of eruptive centers, currently showing several thermal manifestations distributed throughout the area. The structural behavior of this zone is controlled by the El Fierro-El Diablo fault system, corresponding to a high angle reverse faults of Oligocene-Miocene age. In this area, a temporary seismic network with 16 short-period stations was setup from January to April of 2010, in the context of the MSc thesis of Lira (2010), covering an area of 200 km2 that corresponds with the hydrothermal field of Tinguiririca Volcanic Complex (TVC), Central Chile, Southern Central Andes. Using P- and S- wave arrival times, a 3D seismic velocity tomography was performed. The preliminary locations of 2270 earthquakes have first been determined using an a priori 1D velocity model. Afterwards, a joint inversion of both, the 3D velocity model and final locations have been obtained. High Vp/Vs ratios are interpreted as zones with high hot fluid content and high fracturing. Meanwhile, low Vp/Vs anomalies could represent the magmatic reservoir and the conduit network associated to the fluid mobility. Based on structural information and thermal manifestations, these anomalies have been interpreted. In order to visualize the relation between local geology and the velocity model, the volume associated with the magma reservoir and the fluid circulation network has been delimited using an iso-value contour of Vp/Vs equal to 1.70. The most prominent observed feature in the obtained model is a large "V" shaped low-velocity anomaly extending along the entire study region and having the same vergency and orientation as the existing high-angle inverse faults, which corroborates that El Fierro-El Diablo fault system represents the

  9. Caracterización y procedencia de obsidianas de sitios arqueológicos del Centro Oeste de Argentina y Centro de Chile con metodología no destructiva por fluorescencia de Rayos X (XRF Non-destructive x-ray fluorescence (XRF characterization and sourcing of obsidian from archaeological sites in Central West Argentina and Central Chile

    Víctor Durán


    Full Text Available Se presentan los resultados de 101 análisis químicos por fluorescencia de Rayos X efectuados sobre artefactos de obsidiana provenientes de sitios arqueológicos del Centro Oeste Argentino y Chile Central. También se hace una caracterización química de seis fuentes y subfuentes de obsidiana ubicadas en ambientes cordilleranos y extracordilleranos del sur de Mendoza, Neuquén y Chile Central. Con esa información se discuten propuestas referidas a la movilidad y sistemas de intercambio de las sociedades humanas que ocuparon las dos vertientes de la cordillera de Los Andes durante el Holoceno medio y tardío. Los resultados obtenidos confirman que el método no destructivo por XRF es una herramienta válida para determinar el origen y dispersión de las obsidianas arqueológicas.The results of chemical analysis by X-ray Fluorescence (XRF performed on 101 obsidian artifacts from archaeological sites of Central western Argentina and Central Chile are presented. A chemical characterization of six obsidian sources and subsources located in both Andean and extra-Andean environments of Southern Mendoza, Northern Neuquén and Central Chile, is also performed. Based on this information, different proposals related to mobility patterns and exchange systems of human societies that occupied the two slopes of the Andes during the middle and late Holocene are discussed. The results confirm that non-destructive X-ray Fluorescence is a valid tool to determine the origin and dispersal of archaeological obsidian artifacts.

  10. Personajes fuera de lugar: antropomorfos tardíos en el arte rupestre del norte semiárido de Chile Images out of place: late period antropomorphous figures in the rock art of central Chile

    Andrés Troncoso


    , in the Choapa Province, north-central Chile (30°LS. We will discuss the chronology, affinities and relations between these anthropomorphous figures and their northern counterparts and evaluate why they are present in places so far away from their original spatial distribution pattern. Also we discuss the relations between these designs and the image circulation realized by the Tawantinsuyu.

  11. Water input and water release from the subducting Nazca Plate along southern Central Chile (33°S-46°S)

    Völker, David; Stipp, Michael


    The age of the subducting Nazca Plate off Chile increases northward from 0 Ma at the Chile Triple Junction (46°S) to 37 Ma at the latitude of Valparaíso (32°S). Age-related variations in the thermal state of the subducting plate impact on (a) the water influx to the subduction zone, as well as on (b) the volumes of water that are released under the continental fore arc or, alternatively, carried beyond the arc. Southern Central Chile is an ideal setting to study this effect, because other factors for the subduction zone water budget appear constant. We determine the water influx by calculating the crustal water uptake and by modeling the upper mantle serpentinization at the outer rise of the Chile Trench. The water release under fore arc and arc is determined by coupling FEM thermal models of the subducting plate with stability fields of water-releasing mineral reactions for upper and lower crust and hydrated mantle. Results show that both the influx of water stored in, and the outflux of water released from upper crust, lower crust, and mantle vary drastically over segment boundaries. In particular, the oldest and coldest segments carry roughly twice as much water into the subduction zone as the youngest and hottest segments, but their release flux to the fore arc is only about one fourth of the latter. This high variability over a subduction zone of <1500 km length shows that it is insufficient to consider subduction zones as uniform entities in global estimates of subduction zone fluxes.

  12. Mid-cretaceous crustal shortening: evidence from a regional-scale ductile shear zone in the Coastal Range of central Chile (32° S)

    Arancibia, Gloria


    In the Coastal Range of central Chile, widespread Early Cretaceous volcanism associated with extensional volcanosedimetary intra- or back-arc basins and subsequent basin closures, uplift, and increased erosion/exhumation rates during the mid-Cretaceous suggests a major change from a mainly extensional tectonic regime to a relatively contractional regime and resultant crustal shortening. The author documents the contractional Silla del Gobernador shear zone (SGSZ), which developed at the western boundary of the Coastal Range in central Chile (32° S). This structure corresponds to a high-strain ductile and cataclastic shear zone that developed under low-grade (greenschist facies) metamorphic and fluid-present conditions, which indicates EW-NWW crustal shortening in a compressional (transpressional) regime. UVLAMP 40Ar/ 39Ar laserprobe dating of neoformed white mica during mylonitic deformation suggests a maximum age for the reverse ductile shearing of 109±11 Ma. An inverse isochron age of 97.8±1.5 Ma from biotite samples of a mylonitized granodiorite suggests the minimum age of deformation. These ages constrain the ductile deformation age to approximately 100 Ma (mid-Cretaceous), coeval with high exhumation/erosion rates that appear to represent uplift of the Coastal Range. The uplift and crustal shortening of the Coastal Range of central Chile has been associated with high spreading rates from the SE Pacific and southern Atlantic convergence during a change from an extensional regime developed during the Early Cretaceous to a more compressional regime that started during the mid-Cretaceous. In this sense, the SGSZ records this tectonic regime change.

  13. Modelación y análisis probabilístico del balance hídrico superficial de un sistema de riego en Chile Central

    Molina, José Manuel; Gurovich R., Luis A.; Varas, Eduardo


    El presente artículo presenta una propuesta de modelación de los elementos y procesos involucrados en la oferta superficial y demanda hídrica de un sistema de riego de la zona central de Chile, como metodología para el estudio del balance hídrico predial en la planificación de los recursos hídricos disponibles. El estudio contempló una descripción y evaluación general del sistema mediante visitas de terreno y recolección de información, teniendo en cuenta aspectos de suelos, cultivos, agua...

  14. Consideraciones biogeográficas y ecológicas de equinodermos arquibentónicos de Chile Central (com excepción de crinoidea

    Héctor Andrade Vasquez


    Full Text Available 30 echinoderm species (the crinoias excepted have been recorded from the archibenthos off Central Chile. Samples were taken at 5 stations (from Los Vilos to Quíntero. 250-450 m depth range, every 15 days for one year. The concept of Region or Province, usually related to the intertital fauna from high latitudes are showed to be impractical using them with archibenthal echinoderms. The presence oj some species that had been registered as characteristic from the Antarctic Region and/or present in the Argentinian and Magellanic Province is related with the Antarctic Intermediate Water Mass, which is at the capture depth in the sampled area.

  15. The Jurassic-Cretaceous Boundary (Tithonian - Hauterivian) in the Andean Basin of Central Chile: Ammonites, Bio- and Sequence Stratigraphy and Palaeobiogeography

    Salazar Soto, Christian Andrés


    Five sections of the Baños del Flaco and Lo Valdés formations in the High Andean Cordillera of Central Chile have been analyzed with regard to sediment, bio- and sequence stratigraphy, ammonite assemblages and palaeobiogeography, in order to reveal the age and depositional facies of the sediment sequence, and to evaluate the age and important bioevents across the Jurassic-Cretaceous boundary. The Baños del Flaco Formation was investigated at Rio Tinguiririca and in the Rio Maitenes valley,...

  16. Hábitos tróficos de la reineta Brama australis (Pisces: Bramidae durante el periodo estival frente a Chile central

    Francisco Santa Cruz


    Full Text Available La reineta Brama australis es un importante recurso pesquero artesanal en la zona central chilena, incorporado en los programas de seguimiento biológico, pero con escasas evaluaciones de sus aspectos tróficos. Para actualizar el estado del conocimiento, se analizó su dieta durante el verano austral época de mayor disponibilidad de este recurso en la zona central de Chile, mediante el análisis del contenido gástrico de 300 ejemplares capturados entre noviembre 2011 y marzo 2012. Se identificó una dieta dominada por Euphausia mucronata (IIR = 92,33, aunque a escala mensual se identificó una dieta mixta de E. mucronata durante noviembre, diciembre 2011 y marzo 2012, además de Pterygosquilla armata y anfípodos hipéridos durante enero y marzo 2012. No se encontró diferencias significativas entre ambos sexos (P > 0,01. Estos resultados demuestran y corroboran que B. australis es un depredador pelágico con un reducido espectro trófico en el litoral de Chile central.

  17. Using fecal profiles of bile acids to assess habitat use by threatened carnivores in the Maulino forest of central Chile Empleo del perfil de ácidos biliares fecales para evaluar uso del hábitat por carnívoros amenazados en el bosque maulino de Chile central



    The distribution and habitat use by carnivores can be assessed by studying their tracks or feces. If these methods are to be used confidently, they should not only unequivocally discriminate among species, but should also render the same patterns of spatial distributions. We assessed the fulfillment of these requirements with five carnivores inhabiting the Maulino forest of central Chile: Galictis cuja, Oncifelis guigna, Pseudalopex culpaeus, Pseudalopex griseus, and Puma concolor. Fecal bile...

  18. Biología reproductiva del águila Geranoaetus melanoleucus (Aves: Accipitridae en Chile central Breeding biology of the black-chested eagle Geranoaetus melanoleucus (Aves: Accipitridae in central Chile



    Full Text Available Durante dos años (julio 1987­enero 1989 se estudió la biología reproductiva del águila (Geranoaetus melanoleucus en San Carlos de Apoquindo, en Chile central. El inicio del período reproductivo se evidenció por un aumento del número de vuelos en pareja. Los cortejos incluyeron vuelos sincronizados de la pareja, capturas, transporte de material al nido y cópulas. Los traspasos de presas ocurrieron durante todo el año, aunque fuera del período reproductivo fueron escasos y forzados por la hembra. Se localizaron 4,7 nidos pareja-1, lo que está en el límite superior documentado para grandes águilas. Fuera del período reproductivo las águilas visitaron ocasionalmente los nidos. Antes de la postura el macho visitó el nido con mayor frecuencia y por menos tiempo que la hembra. En las tres parejas estudiadas se observó visitas a nidos alternativos, con aporte de material y presas. Se promedió 2,3 huevos postura-1 (DE = 0,5, n = 6, incubando macho y hembra, y eclosionando el 100 %. A los 25 días de edad comenzaron a emerger las plumas de vuelo de los pollos, a los 35 días comían solos las presas aportadas al nido y a los 59 días abandonaron el nido. Durante la crianza la hembra permaneció más tiempo en el nido que el macho, con una tendencia de los adultos a disminuir el tiempo de permanencia en el nido. El 79 % de los pollos sobrevivió a la crianza, lo que se puede considerar un éxito reproductivo elevado, y que se explicaría por la elevada disponibilidad de presas en el sitio de estudio, particularmente de conejos. Los pollos permanecieron en el territorio paterno 10 meses, lo que coincidió con la siguiente postura de huevos, disminuyendo gradualmente su presencia en el área y aumentando la intolerancia de los adultos hacia sus hijos. Los resultados presentados se corresponden con el patrón descrito en la literatura para otras águilasThe breeding biology of the black-chested eagle (Geranoaetus melanoleucus was studied

  19. Constraining the magma flow record based on magmatic and magnetic data in La Gloria Pluton, central Chile

    Gutierrez, F. J.; Payacán, I.; Gelman, S. E.; Bachmann, O.; Creative Physical Petrology Team


    The magmatic origin of the anisotropy of magnetic susceptibility (AMS) is examined in comparison with magmatic anisotropy data in a small, shallow, silicic magma reservoir in the upper crust. La Gloria Pluton (LGP) is a 10 Ma granodiorite/quartz monzonite of about 250 km3 located in the southern Andes, central Chile. LGP represents a particularly simple case of a silicic intrusion that was assembled in only a few pulses and cooled over a short time interval. Hornblende, biotite and minor magnetite are ubiquitous mafic phases. The AMS tensor indicates that magnetic fabric has an oblate shape (i.e. magnetic foliation is higher than magnetic lineation). Lineations are weak (values up to 1.05), have a N-NW trend with a nearly horizontal dip and are interpreted to represent axisymmetric convection parallel to the main pluton elongation. Foliations are more pronounced (values up to 1.14), having NW trends and dips that vary gradually from vertical at the walls, to horizontal at the center and near the roof of the chamber. We selected 12 samples from AMS sites to obtain petrographic data (well-distributed throughout the pluton, containing samples from the walls, the center and the roof of LGP), and then, determine the magmatic fabric (anisotropy, lineation, foliation). We made 3 oriented thin sections per sample oriented with the AMS. Magmatic anisotropy data were obtained by measuring mineral length, width and orientation in photomicrographs of the three main planes of the AMS tensor, producing 3-D mineral data which were collected for plagioclase and amphibole + bitotite independently. For each site, a Bingham distribution with 95% of confidence is used to determine the mean mineral orientations and their angle difference with the AMS axes. Magmatic anisotropy tensor and rotations with respect to the AMS tensor are determined using both eigenvalues and minimization algorithms. Preliminary results indicate that crystals are coherently oriented in both mineral groups, and

  20. Chemosynthetic trophic support for the benthic community at an intertidal cold seep site at Mocha Island off central Chile

    Sellanes, Javier; Zapata-Hernández, Germán; Pantoja, Silvio; Jessen, Gerdhard L.


    We analyzed C and N stable isotope ratios of benthic fauna and their potential food sources at an intertidal methane seep site and a control site without emanation at Mocha Island (central Chile). The objective was to trace the origin of the main food sources used by the local heterotrophic fauna, based on the hypothesis that chemosynthetic production could be partially fueling the local food web at the seep site. Food sources sampled at both sites included macroalgae, particulate organic matter and bacteria-like filaments found growing over the red algae Gelidium lingulatum within the areas of active methane release. At the control site, located 11 km away from the gas emanation, fauna exhibited moderate δ 13C values ranging from -16.2‰ (in a nereid polychaete) to -14.8‰ (in a cirolanid isopod), which were consistent with those of the potential photosynthetic food sources sampled at this site (-20.2 to -16.5‰). δ 13C values of the photosynthetic food sources at the seep site similarly ranged between -25.4 and -17.9‰. However, a portion of the animals at this site were consistently more 13C-depleted, with δ 13C values close to that of the seeping methane (-43.8‰) and the bacteria-like filaments (-39.2 ± 2.5‰) also collected at this site. Specific examples were the Marphysa sp. polychaetes (δ 13C = -44.7 ± 0.6‰), the Schistomeringos sp. dorvilleid polychaetes (δ 13C = -42.9‰), and the tanaid crustacean Zeuxo marmoratus (δ 13C = -37.3 ± 0.2‰). The significantly higher δ 13C values of the herbivorous gastropod Tegula atra at the seep site (-29.3 ± 3.1‰) than at the control site (-12.6 ± 0.3‰) also indicated differences among sites of the preferred carbon sources of this species. Mixing model estimates indicate that at the seep site bacteria-like filaments could be contributing up to ˜60% of the assimilated diet of selected invertebrates. Furthermore, several indicators of trophic structure, based in isotopic niche metrics, indicate a

  1. Persistent toxic substances in soils and waters along an altitudinal gradient in the Laja River Basin, Central Southern Chile.

    Barra, Ricardo; Popp, Peter; Quiroz, Roberto; Bauer, Coretta; Cid, Hernan; von Tümpling, Wolf


    In this study the levels and distribution of some persistent toxic substances (PTS) were investigated in soils, superficial water, and snow along an altitudinal gradient in the Laja River Basin (South Central Chile). The principal objective was to establish the basin's contamination status. The working hypothesis was that PTS levels and distribution in the basin are dependent on the degree of anthropogenic intervention. Fifteen PAHs, seven PCBs congeners, and three organochlorine pesticides were studied in superficial soil and water samples obtained along the altitudinal gradient and from a coastal reference station (Lleu-Lleu River). Soil samples were extracted using accelerated solvent extraction with acetone/cyclohexane (1:1) for PAHs and organochlorine compounds. Contaminants were extracted from water and snow samples by liquid-liquid extraction (LLE). PAH and organochlorine compound quantification was carried out by HPLC with fluorescence detection and GC-MS, respectively. PCBs in soils presented four different profiles in the altitudinal gradient, mainly determined by their chlorination degree; these profiles were not observed for the chlorinated pesticides. In general, the detected levels for the analyzed compounds were low for soils when compared with soil data from other remote areas of the world. Higher summation operator PAHs levels in soils were found in the station located at 227 masl (4243 ng g-1 TOC), in a forestry area and near a timber industry, where detected levels were up to eight times higher than the other sampling sites. In general, PAH levels and distribution seems to be dependent on local conditions. No pesticides were detected in surface waters. However, congeners of PCBs were detected in almost all sampling stations with the highest levels being found in Laja Lake waters, where 1.1 ng/l were observed. This concentration is two times higher than values reported for polluted lakes in the Northern Hemisphere. The presence of organochlorine

  2. Combined impact of ocean acidification and corrosive waters in a river-influenced coastal upwelling area off Central Chile

    Vargas, C.; De La Hoz, M.; San Martin, V.; Contreras, P.; Navarro, J. M.; Lagos, N. A.; Lardies, M.; Manríquez, P. H.; Torres, R.


    Elevated CO2 in the atmosphere promotes a cascade of physical and chemical changes affecting all levels of biological organization, and the evidence from local to global scales has shown that such anthropogenic climate change has triggered significant responses in the Earth's biota. The increased concentration of CO2 is likely to cause a corresponding increase in ocean acidification (OA). In addition, economically valuable shellfish species predominantly inhabit coastal regions both in natural stocks and/or in managed stocks and farming areas. Many coastal ecosystems may experience seawater pCO2 levels significantly higher than expected from equilibrium with the atmosphere, which in this case are strongly linked to biological processes and/or the impact of two important processes; river plumes and coastal upwelling events, which indeed interplay in a very dynamic way on continental shelves, resulting in both source or sink of CO2 to the atmosphere. Coastal ecosystems receive persistent acid inputs as a result of freshwater discharges from river basins into the coastal domain. In this context, since shellfish resources and shellfish aquaculture activities predominantly occur in nearshore areas, it is expected that shellfish species inhabiting river-influenced benthic ecosystems will be exposed persistently to acidic conditions that are suboptimal for its development. In a wider ecological context, little is also known about the potential impacts of acid waters on the performance of larvae and juveniles of almost all the marine species inhabiting this benthic ecosystem in Eastern Southern Pacific Ocean. We present here the main results of a research study aimed to investigate the environmental conditions to which economically valuable calcifiers shellfish species are exposed in a river-influenced continental shelf off Central Chile. By using isotopic measurements in the dissolved inorganic carbon (DIC) pool (d13C-DIC) we showed the effect of the remineralization of

  3. Future Temperatures and Precipitations in the Arid Northern-Central Chile: A Multi-Model Downscaling Approach

    Souvignet, M.; Heinrich, J.


    Downscaling of global climate outputs is necessary to transfer projections of potential climate change scenarios to local levels. This is of special interest to dry mountainous areas, which are particularly vulnerable to climate change due to risks of reduced freshwater availability. These areas play a key role for hydrology since they usually receive the highest local precipitation rates stored in form of snow and glaciers. In the central-northern Chile (Norte Chico, 26-33ºS), where agriculture still serves as a backbone of the economy as well as ensures the well being of people, the knowledge of water resources availability is essential. The region is characterised by a semiarid climate with a mean annual precipitation inferior to 100mm. Moreover, the local climate is also highly influenced by the ENSO phenomenon, which accounts for the strong inter-annual variability in precipitation patterns. Although historical and spatially extensive precipitation data in the headwaters of the basins in this region are not readily available, records at coastal stations show worrisome trends. For instance, the average precipitation in La Serena, the most important city located in the Coquimbo Region, has decreased dramatically in the past 100 years. The 30-year monthly average has decreased from 170 mm in the early 20th century to values less than 80 mm nowadays. Climate Change is expected to strengthen this pattern in the region, and therefore strongly influence local hydrological patterns. The objectives of this study are i) to develop climate change scenarios (2046-2099) for the Norte Chico using multi-model predictions in terms of temperatures and precipitations, and ii) to compare the efficiency of two downscaling techniques in arid mountainous regions. In addition, this study aims at iii) providing decision makers with sound analysis of potential impact of Climate Change on streamflow in the region. For the present study, future local climate scenarios were developed

  4. A study of the relationship between degree of ethnocentrism and typologies of food purchase in supermarkets in central-southern Chile.

    Schnettler, Berta; Miranda, Horacio; Lobos, Germán; Sepúlveda, José; Denegri, Marianela


    The objective of this study was to distinguish different types of consumers according to their level of ethnocentrism in relation to the consumption of foodstuffs in central-southern Chile. To do this a modification of the CETSCALE (Consumer Ethnocentric Tendencies Scale) was applied through direct survey of 800 habitual supermarket shoppers in two cities in central-southern Chile. The modified CETSCALE presented a sufficient level of internal consistency and there were three factors which included the 17 items of the scale. Five typologies of consumer with different degrees of ethnocentrism were distinguished by cluster analysis, based on the values of the factors and items in the CETSCALE. The composition of the typologies of consumers were related to the city and zone of residence, age, socioeconomic level, self-declared life-style, ethnic origin, knowledge of the origin of the foodstuffs purchased, frequency of purchase of imported foodstuffs and reasons for rejection in the case of a low purchase frequency. It may therefore be concluded that different levels of ethnocentrism exist in the consumption of foodstuffs, related with some socio-demographic characteristics of consumers and their attitudes to imported foodstuffs. PMID:21335039

  5. Cambios de largo plazo en el paisaje y los ensambles de micromamíferos y rapaces en Chile central Long-term changes in landscape and in small mammal and raptor assemblages in central Chile



    Full Text Available San Carlos de Apoquindo, en la precordillera de Chile central, es una localidad con estudios de larga data en vertebrados (ca. 30 años, situación favorable para el análisis de procesos de largo plazo que operan sobre dichos ensambles. En este contexto estudiamos la trayectoria del uso del suelo mediante imágenes satelitales LANDSAT, correspondientes a 1975, 1989 y 2003 y su presunto efecto sobre la vegetación, micromamíferos y aves rapaces. El análisis de las imágenes satelitales revela una expansión acelerada del área urbana en desmedro del suelo agrícola y matorrales naturales. Las especies de micromamíferos nativos de talla reducida y media no evidencian grandes variaciones de abundancia durante el período de estudio pero las de mayor tamaño redujeron sus poblaciones. El conejo europeo (Oryctolagus cuniculus es una de las especies más abundantes del área, y estaría siendo favorecido por la modificación del paisaje. En la dieta del águila (Geranoaetus melanoleucus y del peuco (Parabuteo unicinctus se observó una disminución sostenida de la principal presa nativa, el degú (Octodon degus y un aumento de la presa exótica, el conejo. Además se observó una tendencia a la disminución de la riqueza y abundancia de aves rapaces durante el período de estudio, la que se asociaría a la expansión urbana y al deterioro del matorral natural. Postulamos que la expansión urbana y la pérdida y fragmentación del matorral han producido una disminución de la población de degú, con su consecuente disminución en la dieta de águilas y peucos, lo que a su vez ha potenciado un incremento de depredación sobre conejo.San Carlos de Apoquindo, a piedemont area to the east of Santiago city, is a site with 30 years of data on vertebrates. Using LANDSAT satellite imagery for the years 1975, 1989 and 2003, we studied the spatio-temporal trajectory of land use and its putative effects on vegetation, small mammals and raptors. On the basis

  6. Infrastructure development and agricultural exposure to climate variability and change: lessons from the Limarí basin in Central Chile

    Vicuna, S.; Alvarez, P.; Melo, O.; Dale, L. L.; Meza, F. J.


    The Limarí basin, located in Central Chile, is a world famous example of how the development of reservoirs and irrigation infrastructure can reduce climate vulnerabilities allowing the economic development of a basin. Before the infrastructure was developed low value crops such as cereals dominated land use acreage. Today high value crops such as vineyards, orchards and vegetables account for almost 50% of total land and cereals have almost disappear. Key to this evolution have been the reduction in water supply variability, access to international markets, increased irrigation efficiency, and the existence of water markets and other flexible and strong institutions that have helped moving the water from low to high value uses. These factors are related to each other sharing infrastructure development as a common root. The system of reservoirs in the Limarí basin was designed and has been operated since its construction with the premise that droughts in this basin do not last longer than 4 years. Until recently that had been the case and farmers have been able to withstand the impacts of droughts. When faced with water supply reductions farmers would select from a set of options to accommodate their needs including: water market participation, groundwater extraction and crop irrigation and crop acreage decisions. The use of these options has even allowed increasing total irrigated land mostly through the expansion of permanent water demand crops. In the past 9 years however, the basin has experienced a longer than usual drought, interrupting the reservoir refilling cycle that characterized climate variability in the region. This situation has led to dramatically low reservoir levels and continuous reductions in water supply. In addition, due to the already high levels of irrigation efficiency and large amount of acreage devoted to permanent water demand crops, the effectiveness of the portfolio of options available to farmers to accommodate to these stressing

  7. Sr-Nd-Pb isotope compositions of felsic intrusions in the El Teniente and Laguna La Huifa areas, Central Chile

    The giant El Teniente porphyry Cu-Mo deposit is located in the Andes foothills of Central Chile (34oS). In simplistic terms, the igneous rocks at the mine can be grouped in two major units: a felsic suite of silicic intrusives (the porphyries; SiO2≥56wt%) with subvertical stock-like to dyke shapes, and a mafic volcanic to subvolcanic sequence (the Farellones formation; SiO2<≤56wt%) with a sub-horizontal nature. The felsic rocks intrude the volcanogenic Farellones formation, which is known at the mine site as 'Andesitas de la mina'. The major felsic intrusives are locally known as the 'Diorita Sewell' and 'Porfido Teniente' bodies, plus a series of minor plugs, apophyses and dikes. According to Cuadra (1986), the age of the main intrusive units spans from Late Miocene ('Diorita Sewell'; 7-8Ma) to Early Pliocene ('Porfido Teniente'; ∼4-5Ma). These felsic intrusives are closely related to copper mineralization ( ∼4-5Ma; Cuadra, 1986), particularly the younger 'Porfido Teniente' (Camus, 1975). Additionally, Skewes and Stern (1996) have suggested the existence of an even slightly younger porphyry pluton, not exposed at surface, but still linked to the ore genesis. Similar felsic intrusive bodies are also present in the Laguna La Huifa area (Reich, 2001), located less than 3 km to the NE from the main El Teniente body. The copper mineralization here, is interpreted to be almost contemporaneous with the El Teniente mineralization (Cuadra, 1986). Based on petrographic and geochemical information on the silicic intrusive suite, Rabbia et al. (2000) suggested that this magmatism could be considered as a Phanerozoic equivalent of an Archean high-Al TTG. Furthermore it may be classified as a modified (Na-rich) 'I' type granitoid, in the sense of Atherton and Petford (1993) and Petford and Atherton (1996). According to these authors, the younger (and hotter) lower Andean crust would be a better candidate than the older (and colder) subducted Nazca plate basalts (NPB

  8. Photosynthetic performance of Colobanthus quitensis (Kunth Bartl. (Caryophyllaceae in a high-elevation site of the Andes of central Chile Desempeño fotosintético de Colobanthus quitensis (Kunth Bartl. (Caryophyllaceae en los Andes de Chile central



    Full Text Available Photosynthesis of Colobanthus quitensis and mesoclimatic conditions of air temperature and light intensity during the growing season were investigated at 2,650 m in the central Chilean Andes. On three typical days of the growing period (January, March and May, CO2 exchange and chlorophyll fluorescence were measured. In addition, a series of fluorescence response curves with increasing light intensity at different temperatures were performed to estimate the propensity of Andean C. quitensis populations to be photoinhibited. Net Photosynthesis (Pn was low (ca. 2.0 mmol CO2 m-2s-1 during the morning and noon in days with high photosynthetic active radiation (PAR, above 1,800 mmol photons m-2s-1. Pn increased in the afternoon (3.5-4.8 mmol CO2 m-2s-1 when PAR decreased to ca. 1,400 mmol photons m-2s-1 and leaf temperature were ca. 20 °C. Fv/Fm in the diurnal periods was between 0.7-0.75 without evidence of photoinhibition. Leaves at 15 and 22 °C exhibited a slow decrease of F PSII with the increase in actinic light intensity, although the fraction of reaction centers open (expressed by qP remained higher at 22 °C. NPQ was saturated at light intensities close to 500 mmol photons m-2s-1 in leaves at 22 °C and at higher intensities at 15 °C, suggesting that NPQ could be a mechanism of energy dissipation at high light intensity and high leaf temperature in the field. Our results indicated that C. quitensis is not photodamaged during the diurnal cycle and that the low Pn registered during some diurnal periods are likely to be related with photorespiration, which has been suggested as an efficient protective mechanism for photoinhibition in alpine plants. Our results are also compared with the photosynthetic performance of C. quitensis populations from the maritime AntarcticSe estudió la fotosíntesis de Colobanthus quitensis y las condiciones mesoclimáticas de temperatura del aire e intensidad lumínica a 2.650 m en los Andes de Chile central. Se

  9. Spatio-temporal variability in ontogenetic guild structure of an intertidal fish assemblage in central Chile Variabilidad espacio-temporal en la estructura de gremios ontogenéticos de un ensamble de peces intermareales de Chile central



    variabilidad en las condiciones ambientales, especialmente en peces intermareales, los que alcanzan varios órdenes de magnitud en tamaño corporal. Sin embargo, la influencia de los cambios ontogenéticos en la membresía gremial sobre la estructura espacio-temporal de los ensambles de peces permanece virtualmente desconocida. En este trabajo estudiamos la variabilidad espacio-temporal en la estructura de los gremios alimenticios ontogenéticos (OFG de los ensambles de peces intermareales que ocurren en el intermareal rocoso de la costa de Chile central. Para esto realizamos an��lisis de componentes principales (PCA y pruebas de aleatorización (pruebas R de la composición relativa de las OFG de estos ensambles, obtenidos de muestreos estacionales en diez pozas intermareales ubicadas en dos alturas de mareas en la zona intermareal en tres localidades entre los 33° y 34° S. En general, los PCA y pruebas R sugieren que la variabilidad espacial domina sobre la variabilidad temporal en la estructura de las OFG, debido principalmente a la alta representatividad de las especies omnívoras en las pozas altas del intermareal en dos de las tres localidades muestreadas. Sin embargo, cambios relacionados a la fenología en la representación de las clases de tamaño de los peces (i.e. reclutamiento de carnívoros en primavera-verano junto con diferencias ontogenéticas en la selección de hábitat (e.g., selección por pozas del intermareal bajo por la OFG de carnívoros de gran tamaño contribuyeron a una diferenciación espacial y temporal de la estructura de la OFG. Finalmente, la representación relativa de cada OFG se correlacionó con la de sus especies dominantes, sin evidencia de una compensación por densidad. Esto sugiere bajos niveles de redundancia funcional entre las especies en cada OFG, lo cual denota la vulnerabilidad del funcionamiento de estos ensambles a perturbaciones sesgadas en tamaño corporal tales como la pesca.

  10. Fallout radionuclides 137Cs and 7Be as an important tool to evaluate effectiveness of no-tillage systems in Central-South Chile

    Since 1970 the process of agricultural intensification has drastically increased soil erosion and associated soil degradation in the coastal mountains of south-central Chile. Due to conventional tillage (with burning of crop residues), over 80% of the soils under agriculture show evidence of compaction below plough depth and erosion rates are described amongst the highest for any agricultural land in Chile. The current study developed a simplified method for using 137Cs depth distribution datasets to estimate soil loss or accumulation at a sampling point under conventional tillage and after the shift to a no-till system. Previous applications of 137Cs measurements had been limited to the estimation of erosion rates during the period extending from the beginning of fallout receipt to the time of sampling. The new procedure allows the change in erosion rates associated with a shift in land tillage practices to be estimated. It represents an innovative application of 137Cs measurements in soil erosion research. In an additional study to assess no-till systems with and without burning of crop residues after harvesting, 7Be was used to quantify the erosion that occurred within the same field area, as a result of burning and a period of extreme rainfall (400 mm in 27 days, May 2005)

  11. Satellite-measured interannual variability of turbid river plumes off central-southern Chile: Spatial patterns and the influence of climate variability

    Saldías, Gonzalo S.; Largier, John L.; Mendes, Renato; Pérez-Santos, Iván; Vargas, Cristian A.; Sobarzo, Marcus


    Ocean color imagery from MODIS (Moderate Resolution Imaging Spectroradiometer) onboard the Aqua platform is used to characterize the interannual variability of turbid river plumes off central-southern Chile. Emphasis is placed on the influence of climate fluctuations, namely El Niño Southern Oscillation (ENSO), the Pacific Decadal Oscillation (PDO), and the Antarctic Oscillation (AAO). Additional satellite data on wind, boat-based hydrographic profiles, and regional climate indices are used to identify the influence of climate variability on the generation of anomalous turbid river plumes. The evolution of salinity at a coastal station on the 90 m isobath between the Itata and Biobío Rivers shows a freshwater surface layer with salinity importance of long-term and high-resolution ocean color observations for studying the temporal evolution of river plumes.

  12. Talla de madurez y época de desove de la reineta (Brama australis Valenciennes, 1836) en la costa central de Chile Maturity size and spawning time of the Pacific pomfret (Brama australis Valenciennes, 1836) in the central coast of Chile

    Elson Leal; Ciro Oyarzún


    La reineta (Brama australis) adquiere cada vez mayor importancia en los desembarques de la pesca artesanal, no obstante, es escasa la información que existe acerca de su biología básica, particularmente sobre su dinámica reproductiva. En este trabajo se determina la época principal de desove de B. australis en la costa central de Chile y la talla de madurez (TM), para lo cual se analizó un total de 1061 individuos capturados frente a Lebu (37º37'S-73º40'W), entre enero y septiembre de 2001. E...

  13. Botanical Composition of Alpaca (Lama pacos Linn.) Diet in a Central Mediterranean Range of Chile Composición Botánica de la Dieta de Alpaca (Lama pacos Linn.) en un Pastizal del Secano Mediterráneo de la Zona Central de Chile

    G Castellaro; F Squella N; F León C; A Raggi S


    The re-introduction of domestic South American camelids (alpacas and llamas) in the central zone of Chile makes it necessary to study their behaviour and adaptability. Since it is fundamental to characterize the camelid’s diet, the present work had as an objective the determination of the plant species selected by the alpacas (Lama pacos Linn.) in different phenological stages (vegetative, reproductive and dry season). The study was carried out over three years in a paddock of 2.5 ha of spars...

  14. Shoreline changes in Concón and Algarrobo bays, central Chile, using an adjustment model Cambios en la línea litoral de las bahías de Algarrobo y Concón, Chile central, a través de un modelo de ajuste

    Carolina Martinez


    Adjustment models for both Algarrobo and Concón bays, central Chile, are presented herein; the results show a nearly logarithmic spiral shape for the shore. Spatial-temporal variations in the shorelines of both bays were found based on aerial photographs from different years. The results indicate important variations in the relative position of the Concón Bay shoreline between 1945 and 2006, with extreme oscillations (-368 to 123.8 m) only occurring in the proximal zone, where the Aconcagua E...

  15. Evolución tectónica, paleogeográfica y metalogénica durante el Cenozoico en los Andes de Chile norte y central e implicaciones para las regiones adyacentes de Bolivia y Argentina Tectonic, paleogeographic, and metallogenic evolution during the Cenozoic in the Andes of Central and Northern Chile and implication for the adjacent regions of Bolivia and Argentina

    Reynaldo Charrier; Marcelo Farías; Víctor Maksaev


    La orogenia incaica dio origen a un importante relieve en el Eoceno Medio, el que se concentró en el ámbito del arco magmático precedente, la Cordillera Incaica. Este relieve positivo de orientación NNE se extendió desde el sur de Perú hasta la región central de Chile y separó dos dominios paleogeográficos que tuvieron evoluciones diferentes durante el resto del Cenozoico. El dominio occidental se caracterizó por el predominio de procesos de erosión y sedimentación. En el dominio oriental tam...

  16. Tectonic styles and crustal shortening of the Central Andes "Pampean" flat-slab segment in northern Chile (27-29°S)

    Martínez, Fernando; Arriagada, César; Peña, Matías; Deckart, Katja; Charrier, Reynaldo


    The Andean orogenic belt, located in the Central Andes "Pampean flat-slab" segment in northern Chile (27-29°S), is composed of two major tectonic regions: the Coastal Cordillera and the Frontal Cordillera. To understand their internal tectonic styles, history of growth and the shortening absorbed by the upper crustal structure of this segment, we combined regional geological mapping data, new ages obtained from radiometric U-Pb dating, and a semibalanced and restored cross-section 225.18 km in length. The results as shown in the previous Mesozoic extensional fault systems, established in northern Chile by the Gondwana breakup, have played a fundamental role in the orogenic buildup. The central structure is characterized by an asymmetric basin (Upper Cretaceous-Paleocene) confined by a doubly vergent fault system composed of inverted faults related to the edges of the Mesozoic Chañarcillo and Lautaro Basins. The U-Pb geochronological data obtained from synorogenic volcano-sedimentary deposits and the angular unconformities recorded between the Cenozoic geological units have revealed that the compressive deformation in this segment started at around ~ 80 Ma by tectonic inversion in the eastern Coastal Cordillera and western Frontal Cordillera, however, the presence of Paleocene and Miocene synorogenic successions at the footwall of the basement reverse faults of the Frontal Cordillera suggests a migration of Andean deformation from the west to the east during the Paleocene-Miocene by propagation of ramps involving inherited basement highs. The pre-compression restoration makes it possible to estimate 40.94 km of minimum shortening, concentrated by inversion anticlines and fault-controlled basement highs across the Frontal Cordillera.

  17. Productivity and Persistence of Yellow Serradela (Ornithopus compressus L. and Biserrula (Biserrula pelecinus L. in the Mediterranean Climate Region of Central Chile Productividad y Persistencia de Serradela Amarilla (Ornithopus compressus L. y Biserrula (Biserrula pelecinus L. en la Región Climática Mediterránea de Chile Central

    Alejandro del Pozo


    Full Text Available The production and sustainability of non-irrigated pastures in the Mediterranean climate region of central Chile is currently limited by the low diversity of valuable species and cultivars of annual forage legumes, able to persist in zones with highly variable annual rainfall, and low fertility or poorly drained soils. In this work, DM production, seed yield, hardseededness and pasture persistence were evaluated for cultivars of yellow serradella (Ornithopus compressus L. and biserrula (Biserrula pelecinus L., in field experiments conducted in the subhumid portion of the Mediterranean climate region of Chile. Burr medic (Medicago polymorpha L. and sub clover (Trifolium subterraneum L. were used as a reference plants. A remarkable DM production and seed yield were observed in biserrula (cvs. Mor96 and Casbah, and in some cultivars of yellow serradella (e.g. Madeira, Santorini; biserrula produced by far the largest number of seeds per m². As was expected for species that produce very high levels of hard-seeds, the regeneration of biserrula and serradella was low in second growing season, but plant density and productivity were high in the third growing season. The use of biserrula and serradela in monoculture or in mixture with other annual legumes, either in pasture-crop rotation or permanent pasture, would contribute to the improvement of the prevailing productive systems in the Mediterranean climate region of central Chile.La producción y la sostenibilidad de las praderas de secano en la región de clima mediterráneo de Chile central están actualmente limitadas por la baja diversidad de especies valiosas y cultivares de leguminosas forrajeras anuales, capaces de persistir en zonas con precipitaciones anuales sumamente variables, y suelos de baja fertilidad o de mal drenaje. En este trabajo se evaluó la producción de fitomasa, producción de semilla, dureza seminal y la persistencia de cultivares de serradela amarilla (Ornithopus

  18. A new record of Equus (Mammalia: Equidae from the Late Pleistocene of central-south Chile Un nuevo registro de Equus (Mammalia: Equidae para el Pleistoceno Superior de Osorno, Chile



    Full Text Available Fourteen dental and bone parts of a horse excavated from the Pilauco paleontological site, Osorno (40°39' S-73°07' W are analysed and interpreted. This site was formed in association with a peat bog located on the banks of the old Damas River and has conserved abundant late Pleistocene mammalian fauna and flora materials. A date of 11457 ± 140 14C yrs B.P. was obtained from a molar and agrees with our stratigraphic age model. We have identified the fossils as pertaining to the species Equus (Amerhippus andium, which confirms its presence in central-south Chile. Furthermore, the recorded geographic location indicate that the metapodial adaptations of the specimens previously described agree with the reconstructed late Pleistocene landscape of Pilauco, dominated by soft volcanic soils and isolated forest patches over large extensions of grasslands.Se analizan e interpretan 14 fósiles correspondientes a dientes y huesos de caballo registrados en el sitio Pilauco, Osorno (40°39' S-73°07' W. El sitio se formó asociado a un pantano en un borde del antiguo río Damas; en él se ha conservado abundante material de mastofauna y flora pleistocénica. Una fecha radiocarbónica de 11457 ± 140 A.P obtenida de un molar, es concordante con el modelo de edad del sitio. La identificación taxonómica permite asociar a los fósiles a la especie Equus (Amerhippus andium, lo que confirma la presencia de la especie en el centro-sur de Chile. Por otra parte, la posición geográfica de los hallazgos y la reconstrucción del paisaje indicarían que se trata de ejemplares cuyas adaptaciones en los metapodios son concordantes para el paisaje pleistocénico de Pilauco dominado por suelos volcánicos blandos, con presencia de bosquetes dispersos en grandes extensiones de praderas de gramíneas.

  19. A new species of Phymaturus of the P. mallimaccii Group from the Andes of central Chile (Iguania: Liolaemidae

    Jaime Troncoso-Palacios


    Full Text Available A new species of Phymaturus from the Provincia Mountain in the San Ramón Mountains in the Metropolitan Region of Chile is described. It is a member of the P. palluma Group and the P. mallimaccii subgroup. The new species can be distinguished from other members of the P. mallimaccii subgroup by having a highly fragmented subocular scale (4 or 5, a preocular scale that is smaller than the canthal, males having a olive dorsum with a diffuse pattern of light bands on the paravertebral fields and a light triangle between the shoulders, which has the apex of the triangle oriented toward the snout. The distribution of new species lies south of that of other members of the P. mallimaccii subgroup, from which it is completely isolated. The low abundance of the new species is noteworthy. Information about the natural history of the lizard is provided and some aspects of unnamed populations of Chilean Phymaturus are discussed.

  20. Seasonal changes in the photosynthetic performance of two evergreen Nothofagus species in south central Chile Cambios estacionales en el desempeño fotosintético de dos especies siempreverdes de Nothofagus en el centro sur de Chile



    Full Text Available The evergreen Nothofagus dombeyi and Nothofagus nitida are important members of the temperate Chilean rainforest. They seldom grow together in nature. Nothofagus nitida is more susceptible to excess light and drought than N. dombeyi. We postulate that the different properties of the photosynthetic apparatus under common garden conditions of these species could explain their contrasting habitat preferences. The two species growing in a common garden in south central Chile were studied. The optimal photochemical efficiency (Fv/Fm of both species remained within normal values (»0.8 with the exception of a decrease in N. dombeyi at midday in summer, suggesting reversible reduction in photochemical efficiency of photosystem II (PSII. During summer the effective photochemical efficiency (F PSII, photochemical quenching (qP, photosynthesis (Amax, stomatal conductance (gs and transpiration rates (E in N. dombeyi were higher than in N. nitida. The highest increments in photoprotective pigments (zeaxanthin + antheraxanthin and lutein contents between predawn and midday were obtained in summer in N. dombeyi. In N. nitida a nocturnal retention of dissipative pigments, without a decrease in Fv/Fm, was found in winter. The results suggest that N. dombeyi showed a better photosynthetic performance than N. nitida under high light, high temperature, and drier conditions. These data support are consistent with the pioneer character of N. dombeyi and the semi-tolerant shade properties and more restricted distribution of N. nitida. These photosynthetic characteristics, along with their freezing and flooding resistance differences, may result from their habitat separationLas siempreverdes, Nothofagus dombeyi y Nothofagus nitida, representantes importantes de los bosques lluviosos templados de Chile, raramente crecen juntos en forma natural. Nothofagus nitida es más sensible al exceso de luz y déficit de agua que N. dombeyi. Se postula que diferentes propiedades

  1. Crypsis in early benthic phases of Brachyuran Decapod Crustaceans in central Chile Cripsis en fases bentónicas tempranas de crustáceos decápodos braquiuros en Chile central



    Full Text Available Although common and in some cases of commercial value, little is known about the mechanisms and processes that affect the distribution and abundance of many species of decapod crustaceans, particularly in Chile. All of these species have planktonic larvae that must settle and recruit before becoming part of the adult segments of their populations. For several of these species we have detected the presence of a variety of color morphs in newly settled individuals. The existence of these morphs in Chilean species is comparable with those observed in other latitudes (e.g., coast of the Gulf of Maine. On the other hand, it is characteristic that the occurrence of these patterns only appears during the early juvenile stages and that after reaching a certain size it disappears, with adults being typically monochromatic. The expression of this pattern in the Chilean subtidal seems to be more pronounced in detritivorous species than in carnivorous ones. We propose that the existence of these kind of phenotypic attributes, apparently generalized in brachyuran decapods, could play an important role both from an ecological as well as evolutionary point of viewAunque comunes, y en algunos casos de valor comercial, poco es lo que se conoce acerca de los mecanismos y procesos que afectan la distribución y abundancia de muchas especies de crustáceos decápodos, particularmente en Chile. Todas estas especies poseen larvas planctónicas que deben asentarse y reclutar antes de pasar a formar parte de los segmentos adultos de sus poblaciones. En varias de estas especies hemos detectado la presencia de una variedad de morfos de coloración en individuos recién asentados. La existencia de dichos morfos en especies chilenas es comparable con aquellos observados en otras latitudes (e.g., costa del Golfo de Maine. Por otro lado, es característica la aparición de estos patrones solo durante los estadíos juveniles tempranos y, al alcanzar cierto tamaño, estos

  2. Presencia del tiburón martillo Sphyrna zygaena (Carchariniformes: Sphyrnidae y nuevo registro del tiburón espinudo Echinorhinus cookei (Squaliformes: Squalidae en San Antonio, Chile central Presence of the smooth hammerhead Sphyrna zygaena (Carchariniformes: Sphyrnidae and new records of prickly shark Echinorhinus cookei (Squaliformes: Squalidae in San Antonio, central Chile

    José L. Brito


    Full Text Available Se documenta el registro de Sphyrna zygaena (Linnaeus, 1758, sobre la base de un ejemplar capturado en la bahía de San Antonio (33°35'S y un ejemplar de Echinorhinus cookei Pietschmann, 1928, capturado al oeste de Santo Domingo (33°37'S. En el primer caso, se amplía su distribución geográfica desde Arica hasta San Antonio, y en el segundo, se agrega un quinto registro para esa especie en aguas chilenasThe sighting of Sphyrna zygaena (Linnaeus, 1758 based on the capture of a specimen in the bay of San Antonio (33°35'S and a specimen of Echinorhinus cookei Pietschmann, 1928 captured to the west of the coast of Santo Domingo (33°35'S. The former case, the known geographic distribution is increased from region to the north to San Antonio, in central Chile and in the alter, a fifth sighting is noted for the species in Chilean waters, confirming its presence in the central region of Chile

  3. Use of 137Cs to estimate tillage- and water-induced soil redistribution rates on agricultural land under different use and management in central-south Chile

    The purpose of this research was to evaluate the applicability of conventional 137Cs sampling and a simplified approach, for estimating medium-term tillage- and water-induced soil erosion and sedimentation rates on agricultural land in Chile. For this purpose, four study sites under contrasting land use and management were selected in central-south Chile. First, a conventional 137Cs approach, based on grid sampling was applied, adapting a mass balance conversion model incorporating soil movement by tillage to the site specific conditions of the study region. Secondly, using the same conversion model, the feasibility of estimating soil redistribution rates from measurements of 137Cs inventories based on composite soil samples taken along contour lines was also tested at all four sites. The redistribution rates associated with tillage and water and the total rates estimated using both methods correlated strongly at all four sites. The conventional method provides more detailed information concerning the redistribution processes operating over the landscape. The simplified method is suitable for assessing soil loss and sediment accumulation in areas exhibiting simple topography and almost similar slopes along the contour lines. Under these conditions, this method permits faster estimation of soil redistribution rates, providing the possibility of estimating soil redistribution rates over larger areas in a shorter time. In order to optimise the costs and benefits of the methods, the sampling and inventory quantification strategy must be selected according to the resolution of the required information, and the scale and complexity of the landscape relief. Higher tillage- and water-induced erosion rates were observed in the annually ploughed cropland sites than in the semi-permanent grassland sites. Subsistence managed crop and grassland sites also show greater erosion effects than the commercially managed sites. The 137Cs methods used permit discrimination between

  4. Air quality forecasting for winter-time PM2.5 episodes occurring in multiple cities in central and southern Chile

    Saide, Pablo E.; Mena-Carrasco, Marcelo; Tolvett, Sebastian; Hernandez, Pablo; Carmichael, Gregory R.


    Episodic air quality degradation due to particles occurs in multiple cities in central and southern Chile during the austral winter reaching levels up to 300-800 µg/m3 hourly PM2.5, which can be associated with severe effects on human health. An air quality prediction system is developed to predict such events in near real time up to 3 days in advance for nine cities with regular air quality monitoring: Santiago, Rancagua, Curicó, Talca, Chillan, Los Ángeles, Temuco, Valdivia, and Osorno. The system uses the Weather Research and Forecasting with Chemistry model configured with a nested 2 km grid-spacing domain to predict weather and inert tracers. The tracers are converted to hourly PM2.5 concentrations using an observationally based calibration which is substantially less computationally intensive than a full chemistry model. The conversion takes into account processes occurring in these cities, including higher likelihood of episode occurrence during weekends and during colder days, the latter related to increased wood-burning-stove activity for heating. The system is calibrated and evaluated for April-August 2014 where it has an overall skill of 53-72% of episodes accurately forecasted (61-76% for the best initialization) which is better than persistence for most stations. Forecasts one, two, and three days in advance all have skill in forecasting events but often present large variability within them due to different meteorological initializations. The system is being implemented in Chile to assist authority decisions not only to warn the population but also to take contingency-based emission restrictions to try to avoid severe pollution events.

  5. Comparison of Airborne LiDAR and Satellite Hyperspectral Remote Sensing to Estimate Vascular Plant Richness in Deciduous Mediterranean Forests of Central Chile

    Andrés Ceballos


    Full Text Available The Andes foothills of central Chile are characterized by high levels of floristic diversity in a scenario, which offers little protection by public protected areas. Knowledge of the spatial distribution of this diversity must be gained in order to aid in conservation management. Heterogeneous environmental conditions involve an important number of niches closely related to species richness. Remote sensing information derived from satellite hyperspectral and airborne Light Detection and Ranging (LiDAR data can be used as proxies to generate a spatial prediction of vascular plant richness. This study aimed to estimate the spatial distribution of plant species richness using remote sensing in the Andes foothills of the Maule Region, Chile. This region has a secondary deciduous forest dominated by Nothofagus obliqua mixed with sclerophyll species. Floristic measurements were performed using a nested plot design with 60 plots of 225 m2 each. Multiple predictors were evaluated: 30 topographical and vegetation structure indexes from LiDAR data, and 32 spectral indexes and band transformations from the EO1-Hyperion sensor. A random forest algorithm was used to identify relevant variables in richness prediction, and these variables were used in turn to obtain a final multiple linear regression predictive model (Adjusted R2 = 0.651; RSE = 3.69. An independent validation survey was performed with significant results (Adjusted R2 = 0.571, RMSE = 5.05. Selected variables were statistically significant: catchment slope, altitude, standard deviation of slope, average slope, Multiresolution Ridge Top Flatness index (MrRTF and Digital Crown Height Model (DCM. The information provided by LiDAR delivered the best predictors, whereas hyperspectral data were discarded due to their low predictive power.

  6. Long-term responses of sandy beach crustaceans to the effects of coastal armouring after the 2010 Maule earthquake in South Central Chile

    Rodil, Iván F.; Jaramillo, Eduardo; Acuña, Emilio; Manzano, Mario; Velasquez, Carlos


    Earthquakes and tsunamis are large physical disturbances frequently striking the coast of Chile with dramatic effects on intertidal habitats. Armouring structures built as societal responses to beach erosion and shoreline retreat are also responsible of coastal squeeze and habitat loss. The ecological implications of interactions between coastal armouring and earthquakes have recently started to be studied for beach ecosystems. How long interactive impacts persist is still unclear because monitoring after disturbance generally extends for a few months. During five years after the Maule earthquake (South Central Chile, February 27th 2010) we monitored the variability in population abundances of the most common crustacean inhabitants of different beach zones (i.e. upper, medium, and lower intertidal) at two armoured (one concrete seawall and one rocky revetment) and one unarmoured sites along the sandy beach of Llico. Beach morphology changed after the earthquake-mediated uplift, restoring upper- and mid-shore armoured levels that were rapidly colonized by typical crustacean species. However, post-earthquake increasing human activities affected the colonization process of sandy beach crustaceans in front of the seawall. Lower-shore crab Emerita analoga was the less affected by armouring structures, and it was the only crustacean species present at the three sites before and after the earthquake. This study shows that field sampling carried out promptly after major disturbances, and monitoring of the affected sites long after the disturbance is gone are effective approaches to increase the knowledge on the interactive effects of large-scale natural phenomena and artificial defences on beach ecology.

  7. VariaciOn morfolOgica de Phacelia secunda J.F. Gmel. (Hydrophyllaceae a lo largo de un gradiente a ltitudinal en Chile central Morphological variation of Phacelia secunda J.F. Gmel. (Hydrophyllaceae along an altitudinal gradient in central Chile

    Lohengrin A. Cavieres


    Full Text Available Phacelia secunda J.F. Gmel. (Hydrophyllaceae es una hierba perenne que en Chile, y también en Argentina, presenta una amplia distribución, habitando desde Parinacota (18°S hasta Tierra del Fuego (54°S, y desde el nivel del mar hasta la alta cordillera. En este estudio se documentan algunas variaciones morfológicas que presenta esta especie a lo largo de un gradiente altitudinal desde los 1.600 m a los 3.400 m en los Andes de Chile central (33°S. Se encontró que el diámetro de las rosetas aumenta significativamente con la altitud, al igual que el número de inflorescencias por individuo y la longitud de la pubescencia. Por el contrario, la altura de las inflorescencias disminuye con la altitud. La tendencia a privilegiar el crecimiento vertical a bajas altitudes y el crecimiento horizontal en altitudes mayores sería una respuesta adaptativa a las frías condiciones de los ambientes de alta montaña. Del mismo modo, el aumento en la longitud de la pubescencia con la altitud sería una adaptación para mantener un balance térmico positivo y evitar los excesos de radiación en dichos ambientesPhacelia secunda J.F. Gmel. (Hydrophyllaceae is a perennial herb that both, in Chile and Argentina, shows a wide distributional range, inhabiting from Parinacota (18°S to Tierra del Fuego (54°S, and from the sea level up to the high Andes. In this study some morphological variations along an altitudinal gradient from 1600 to 3400 m in Andes of central Chile (33°S are reported. The diameter of the rosettes significantly increased with elevation, as well as the number of inflorescences per individual and the longitude of pubescence. In contrast, the height of inflorescences decreased with elevation. Tendencies for privileging vertical growth at lower elevations and horizontal growth at higher elevations would be adaptations to the cold and harsh climate of high mountain habitats. In a similar vein, the increase in the longitude of pubescence with

  8. Determination of trace elements in Pre-Hispanic ceramics from Chile's Central Zone using instrumental neutron activation analysis

    The determination of the element composition in archaeological ceramics is an often unexplored potential, that could provide a unique set of data to verify regional economic and socio-political hypotheses. By chemically defining the elements in these materials, their manufacturing and production centers may be identified, as well as the territorial and social organization of the peoples. Appropriate analytical methodologies for this type of research are limited since there are strict requirements with reference to precision, sensitivity and detection limits, all characteristics that the activation analysis technique provides. The Chilean Nuclear Energy Commission, the University of Chile, the Smithsonian Institution and the International Atomic Energy Agency developed together a cooperative interregional project to promote interdisciplinary research, to resolve archaeological problems and to develop a new application for a nuclear analytical technique. Until this work was undertaken, no systematic studies of trace elements in archaeological ceramics had been done in Chile using the technique of Instrumental Neutron Activation Analysis (INAA). This analytical technique was used in this research to chemically characterize archaeological pieces with the sensitivity, precision and accuracy needed to be able to work with mathematical models that can or cannot establish relationships between the different samples. Protocols were defined first for preparing the pottery samples in order to generate representative samples that could be analyzed by INAA. The homogeneity in preparing the samples used was defined using a group of elements that could be determined by INAA with a precision under 2%. A group of 18 elements was selected and an analytical test procedure was planned that included the type of packaging for the irradiation, the irradiation times, decline and count, the standards to be used and the type of monitor for correcting the neutron flow. The methodology used

  9. Polyphenol content and antioxidant activity of maqui (Aristotelia chilensis Molina Stuntz during fruit development and maturation in Central Chile Contenidos de polifenoles y actividad antioxidante de maqui (Aristotelia chilensis Molina Stuntz durante el desarrollo y maduración de frutos en Chile Central

    Carolina Fredes


    Full Text Available Maqui (Aristotelia chilensis Molina Stuntz, Elaeocarpaceae is a Chilean native species which produces small berries that are mainly collected from the wild. The health benefits of maqui fruit are attributed to their high polyphenol content as well as their wide variety of anthocyanins and flavonols. One of the main factors that affect the polyphenol content in fruit is the maturity stage at harvest. The objective of this study was to determine total phenol and total anthocyanin content and antioxidant activity (by ferric reducing ability of plasma FRAP assay of maqui fruits harvested at different fruit maturity stages from two wild populations located in Central Chile. Each maturity stage was determined by days from fruit set, berry size, and soluble solids. Total phenol content declined while total anthocyanin content increased from the green to light red stage. Nevertheless, both total phenol and anthocyanin content increased from the light red to dark purple stage. The highest anthocyanin content and antioxidant activity was found in the late maturity stage (dark purple. The results show that ripening in maqui fruit can be expected with 1100 growing degree-days (91 d after fruit set in Central Chile. At this moment of harvest, fruits with 18-19 °Brix have the highest anthocyanin content and antioxidant activity (FRAP. This study constitutes the first advances in the understanding of maqui fruit ripening and corresponding antioxidant activity.El maqui (Aristotelia chilensis Molina Stuntz, Elaeocarpaceae es una especie nativa de Chile que produce unas bayas pequeñas que se recolectan principalmente de individuos silvestres. Los beneficios para la salud atribuidos a los frutos de maqui se deben a sus altos contenidos de polifenoles, así como a la gran variedad de antocianos y flavonoles. Uno de los principales factores que afectan el contenido de polifenoles en frutos es el estado de madurez a la cosecha. El objetivo de este estudio fue

  10. Estudio del comportamiento serológico de Actinobacillus pleuropneumoniae (App en planteles porcinos comerciales de la zona central de Chile Serological behaviour study of Actinobacillus pleuropneumoniae (App in commercial swine herds from the central region of Chile

    D Muñoz


    Full Text Available En Chile se ha realizado sólo un estudio en Actinobacillus pleuropneumoniae (App. Este trabajo pretende determinar la duración de la inmunidad materna, la edad de seroconversión y la prevalencia aparente y verdadera en 7 planteles de cerdos comerciales. Se obtuvieron 60 muestras por plantel, divididas en 10 muestras de suero, de animales de 4, 6, 10, 14,18 y 21 semanas de edad, y analizadas a través de un kit ELISA® comercial. De las 420 muestras se detectaron 134 positivas, de las cuales 112 correspondían a cerdos menores de 10 semanas y sólo 22 provenían de animales mayores de 10 semanas, que seroconvirtieron probablemente debido a una infección de campo. La caída de la inmunidad materna fue alrededor de la 10ª semana de edad. En cuanto a la seroconversión, se observó que a partir de la 18* semana comenzaron a aparecer los animales con anticuerpos circulantes propios. Dos de los siete planteles no seroconvirtieron. Además, dos presentaron una seroconversión igual o superior al 50% a las 18 semanas. La seroprevalencia aparente de App fue de 10,48%, mientras que prevalencia verdadera, mediante dos métodos estadísticos, fue de 9,6% (IC: 7,6% y 11,7% y 10,67% respectivamente. En este trabajo se encontró que la prevalencia es similar a la observada en EE.UU., debido presumiblemente al sistema de producción y a los serotipos que están presentes en ambos países. Por otro lado, si bien la mayoría de los planteles seroconvierten luego de la caída de la inmunidad materna, se observaron diferentes patrones serológicos entre ellos.In Chile, there was only one existing study on App. This study was designed to determine the maternal immunity duration, the age of seroconversion and the apparent and true prevalence in animals from 7 swine commercial herds. 60 samples were taken per herd and divided into 10 serum samples from animals of 4, 6,10,14,18and21 weeks of age, which were analyzed by ELISA®. Out of the 420 samples, 134 were

  11. Breeding distribution and abundance of seabirds on islands off north-central Chile Distribución reproductiva y abundancia de aves marinas en islas del norte y centro de Chile



    Full Text Available Between 1999 and 2003 we collected information on the breeding distribution and abundance of 12 seabird species occurring on nine islands off the coasts of north and central Chile (27°-33°S. The Peruvian booby Sula variegata was the most abundant seabird with a breeding population of ca. 18,000 pairs concentrated in two islands, followed by the Humboldt penguin Spheniscus humboldti with ca. 9,000 pairs, the largest colony being at Chañaral Island with ca. 7,000 pairs. Kelp gulls Larus dominicanus bred at all the surveyed sites in colonies of variable size, ranging from 40 to 2,000 pairs. Peruvian diving-petrels Pelecanoides garnotii and Peruvian pelicans Pelecanus occidentalis bred at restricted sites, but generally in large colonies. Magellanic penguins Spheniscus magellanicus, wedge-rumped storm-petrels Oceanodroma tethys, Neotropical cormorants Hypoleucos brasiliensis, guanay cormorants Leucocarbo bougainvillii, red-legged cormorants Stictocarbo gairmardi, band-tailed gulls Larus belcheri and Inca terns Larosterna inca nested at few sites forming small colonies (from a few to 150 pairs. Two new breeding sites are reported for the Peruvian diving-petrel and nesting of the wedge-rumped storm-petrel is confirmed on the Chilean coast for the first time. Despite protective status, most of the islands showed human disturbance, derived mainly from guano harvesting, egging and tourism. On at least five of these islands we were able to confirm introduced mammals including rats, rabbits and cats. These factors are likely to be detrimental to seabirds and thus demand detailed assessment. Further comprehensive ornithological surveys in other areas are needed so as to improve the scarce knowledge that we currently have on the seabird populations along the Chilean coast

  12. Fungal parasites infect marine diatoms in the upwelling ecosystem of the Humboldt current system off central Chile.

    Gutiérrez, Marcelo H; Jara, Ana M; Pantoja, Silvio


    This is the first report of fungal parasitism of diatoms in a highly productive coastal upwelling ecosystem, based on a year-round time series of diatom and parasitic Chytridiomycota abundance in the Humboldt Current System off Chile (36°30.80'S-73°07.70'W). Our results show co-variation in the presence of Skeletonema, Thalassiosira and Chaetoceros diatoms with attached and detached chytrid sporangia. High abundance of attached sporangia was observed during the austral spring, coinciding with a predominance of Thalassiosira and Skeletonema under active upwelling conditions. Towards the end of austral spring, a decreasing proportion of attached sporangia was accompanied by a decline in abundance of Skeletonema and Thalassiosira and the predominance of Chaetoceros, suggesting specificity and host density dependence of chytrid infection. The new findings on fungal parasitism of diatoms provide further support for the inclusion of Fungi in the current model of the role played by the marine microbial community in the coastal ocean. We propose a conceptual model where Fungi contribute to controlling the dynamics of phytoplankton populations, as well as the release of organic matter and the transfer of organic carbon through the pelagic trophic web in coastal upwelling ecosystems. PMID:26914416

  13. Sedimentology, paleontology and age of the Ayacara and Lago Ranco formations (south-central Chile, 40°- 42°S). Tectonic implications.

    Encinas, Alfonso; Zambrano, Patricio; Bernabe, Pablo; Finger, Kenneth; Buatois, Luis; Duhart, Paul; Valencia, Victor; Fanning, M.; Herve, Francisco


    Deep-marine, Mio-Pliocene strata correlative with the Navidad Formation crop out in different areas along the forearc of south-central Chile (~34°-41°) and have also been recognized in boreholes drilles on the continental shelf. However, at Lago Ranco (40°S) and Ayacara (42°) there are outcrops of marine strata whose age and correlation with these units remain uncertain. These deposits consist of rhythmic successions of sandstone and siltstone representing facies similar to those of the Navidad and correlative formations. These marine successions are known ase the Estratos de Lago Ranco and Ayacara formations. They both crop out in the western Andean Cordillera near the limit with the Intermediate Depression at Lago Ranco and the submerged equivalent of this physiographic unit at Ayacara. There are very few studies carried out on these units and most of them consist on internal reports and unpublished theses.In order to unravel the sedimentary enviroment, age and tectonic history of this area during the Neogene we carried out sedimentological, ichnological and micropaleontological studies. In addition, we carried out U-Pb dating in detrital zircons (LAICPMS and SHRIMP). Our studies show the presence of sedimentary features and ichnofacies typical of deposition in a deep-marine environment for these units..In agreement, benthic foraminifers (Ciclamina incisa and Siphonodosaria sangrinensis) indicate lower bathial depths (1500 m). U-Pb (LAICPMS and SHRIMP) indicate a maximum depositional age of around 20 Ma for these units. In agreement, the occurrence of the planktic foraminifer species Globorotalia siakensis (P22-N14), Globigerinoides quadrilobatus (N6-Recent) and Globigerinoides sikanus (N8-N9) in strata of the Ayacara Formation suggest an early-middle Miocene age for this unit. These data indicate that the area corresponding to the western Main Andean Cordillera in south central Chile, was subjeted to major subsidence during the early-middle Miocene. Major

  14. Estructura comunitaria de diatomeas presentes en los sedimentos superficiales de ocho lagos andinos de Chile central Diatoms community structure in superficial sediments of eight Andean lakes of central Chile



    Full Text Available En este trabajo se analizó la estructura comunitaria de diatomeas depositadas en los sedimentos superficiales de ocho lagos andinos chilenos ubicados entre los 32°49' y 38°48' S. Se encontró un total de 99 taxa de diatomeas, distribuidos en 48 géneros. Del total de taxa, 74 fueron identificados a nivel de especie siendo todos ellos cosmopolitas a excepción de Eunotia andinofrequens, Gomphonema punae, Pinnularia araucanensis y Pinnularia acidicola, entre otras, que están descritos solo para el Hemisferio Sur. Por otro lado, las muestras analizadas presentaron distinta composición florística de diatomeas. De esta manera, en los ensambles diatomológicos depositados en los sedimentos de las lagunas de altura Ocho, Huifa, Ensueño y Negra ubicadas sobre los 2.860 m del nivel del mar, abundaron especies bentónicas, típicas de aguas oligotróficas y acidas como Achnanthidium exiguum, Achnanthidium minutissimum, Encyonema minutum, Pinnularia acidicola y Planothidium lanceolatum. En los ensambles diatomológicos de los lagos Galletué, Icalma y Laja, ubicados bajo los 1.360 m del nivel del mar, abundaron diatomeas planctónicas, características de aguas alcalinas y mesotróficas como Asterionella formosa, Aulacoseira distans, Aulacoseira granulata, Cyclotella stelligera y Rhopalodia gibbaIn this research the taxonomic structure of diatoms in sediments of high mountain lakes was studied. These lakes are located in Chile between 32°49' and 38°48' S in the Andean Cordillera. A total of 99 diatom taxa distributed in 48 genera were identified and all this taxa are cosmopolitan excepting a Eunotia andinofrequens, Gomphonema punae, Pinnularia araucanensis and Pinnularia acidicola, which are know only for the Southern Hemisphere. The assemblages of diatoms were different in the studied lakes. So the high mountain lakes Ocho, Huifa, Ensueño and Negra, dominated benthic diatoms which are typical of oligotrophic and acid waters as Achnanthidium

  15. Synchronous degassing patterns of the neighbouring volcanoes Llaima and Villarrica in south-central Chile: the influence of tidal forces

    Bredemeyer, Stefan; Hansteen, Thor H.


    The neighbouring volcanoes Villarrica and Llaima are two of the most active volcanoes in Chile and both currently degas continuously. We present a semi-continuous time series of SO2 fluxes for Villarrica and Llaima volcanoes. The time series was obtained using five scanning Mini-Differential Optical Absorption Spectrometers (Mini-DOAS, UV spectrometers) over 6 months (13 February to 31 July 2010) and is based on 6,829 scans for Villarrica and 7,165 scans for Llaima. Statistical analyses of the SO2 flux time series reveal a periodicity of degassing maxima about every 7 days, and further a conspicuous synchronicity of the degassing maxima and minima between the two volcanoes. Intra-day variations in SO2 fluxes also show a striking correlation between Villarrica and Llaima. All these patterns correlate well with the trend of the modelled solid Earth tide curves, where the 7-day degassing maxima correspond with both the fortnightly tidal maxima and minima. The intra-day degassing peaks mostly correlate well with the periods of maximum deformation rates during the diurnal tidal cycle, and further with semidiurnal minima in atmospheric pressure, a phenomenon we refer to as "the tidal pump". As there is little time lag between the tidal action and the changes in degassing rates, we infer that degassing at both volcanoes is controlled by conduit convection, involving physical separation between gas and magma at comparatively shallow levels. Variations in daily degassing rates were up to a factor of ca. 12 and 10 for Villarrica and Llaima, respectively, without any noticeable changes in the periodicity. We thus suggest that the described cyclic variations must be taken into account for all comparable volcanoes when using gas monitoring as a tool for volcanic hazard mitigation.

  16. Valinia INIA, a New Early Storage Onion Variety for Central South Chile Valinia INIA, una Nueva Variedad de Cebolla de Guarda Precoz para la Zona Centro Sur de Chile

    María Inés González A


    Full Text Available In Central South Chile, storage onion varieties (Allium cepa L. sold domestically usually begin the maturation process in March, which implies that a large proportion of bulbs do not mature adequately and do not resist prolonged storage. This situation led the Quilamapu vegetable program of the Instituto de Investigaciones Agropecuarias INIA to select an early maturing onion variety. This breeding method involved a recurrent selection with free plant crossing that began in 1994 on a population of 2000 plants of the 'Valenciana' commercial variety. Plants were first selected when they reached physiological maturity (tops down before 28 February, and then for shape, size, storage capacity, and single-centered bulbs. The result of the program was 'Valinia INIA', a type of Valenciana onion variety: early maturing, medium-sized bulb, spherical, yellow, and resistant to sprouting during storage. From the 2001-2002 to the 2008-2009 season, variety assays were carried out to compare 'Valinia INIA' with commercial cultivars, i.e., 'Sintética 14', 'Grano de Oro', and 'Valenciana Cobra'. 'Valinia INIA' precocity exceeded the other varieties in all seasons with a mean of 1.5 wk ahead of 'Sintética 14', which is the earliest commercial variety and more than 2 wk ahead of the other two. Its yield is similar to 'Valenciana Cobra' and higher than the other two varieties. Its storage capacity is similar to 'Grano de Oro' and 'Sintética 14', but greater than 'Valenciana Cobra'.En la zona centro sur de Chile es habitual que las variedades de cebolla (Allium cepa L. de guarda que se comercializan en el pais inicien el proceso de maduración preferentemente en marzo, lo que conlleva a que una gran proporción de bulbos no madure adecuadamente, no resistiendo el almacenaje por un tiempo prolongado. Esta situación llevó al programa de hortalizas del Instituto de Investigaciones Agropecuarias INIA Quilamapu a la selección de una variedad de cebolla de madurez

  17. Fecal Contamination of Groundwater in a Small Rural Dryland Watershed in Central Chile Contaminación Fecal en Agua Subterránea en una Pequeña Cuenca de Secano Rural en Chile Central

    Mariela Valenzuela


    Full Text Available Research on microbiological groundwater quality was conducted in Chile in a rural watershed that has almost no other water source. Forty-two wells were randomly selected and levels of indicator bacteria - total coliforms (TC, fecal coliforms (FC, and fecal streptococci (FS - were repeatedly measured during the four seasons of 2005. The aim of this study was to characterize microbiological groundwater quality, relate indicator levels to certain watershed features and management characteristics which are likely to affect water quality. The dynamics of seasonal temporal contamination was determined with statistical analyses of indicator organism concentrations. Nonparametric tests were used to analyze relationships between bacterial indicators in well water and other variables. TC, FC, and FS were found in all samples indicating the wells had been contaminated with human and animal fecal material. The frequency distribution of microorganisms fitted a logistic distribution. The concentrations appeared to be temporal and levels varied between seasons with higher concentrations in winter. The cause of contamination could be linked to the easy access of domestic animals to the wells and to the permeable well casing material. Local precipitation runoff directly influenced the bacterial concentrations found in the wells.Se realizó una investigación de la calidad microbiológica de las aguas subterráneas en una cuenca rural chilena. En esta cuenca prácticamente no había otra fuente de agua disponible. En 42 pozos seleccionados al azar, se midieron niveles de bacterias indicadoras en cuatro temporadas distintas durante el año 2005. Las bacterias incluyeron coliformes totales (TC, coliformes fecales (FC y Estreptococos fecales (FS. El objetivo fue caracterizar la calidad microbiológica del agua subterránea y relacionar los indicadores con ciertas propiedades y el manejo de la cuenca que pueden afectar la calidad del agua. La dinámica temporal de la

  18. Receiver Function Migration of Broadband Seismograms recorded by the International Maule Aftershock Deployment (IMAD) in Central Chile

    Morell, M.; Beck, S. L.; Roecker, S. W.; Meltzer, A.; Russo, R. M.


    The Mw=8.8 Maule earthquake that occurred off the coast of Chile on February 27, 2010 is one of the largest megathrust earthquakes ever to be recorded and ruptured ~600 km of the plate boundary. This segment of the Nazca-South America plate boundary is an ideal region to investigate the processes related to the structure of the down-dip edge of the seismogenic zone, forearc wedge and subducting slab. Immediately after the Maule earthquake, international teams from France, Germany, Great Britain and the United States joined Chilean seismologists to install an array of seismic stations between 33°-38.5°S, from the coast to the foothills of the Andes to produce the International Maule Aftershock Deployment (IMAD) data set. These arrays were deployed from mid-March until the end of December 2010 in order to capture and study the aftershocks in and around the rupture zone, and to better understand crustal and mantle wedge structure. We calculated receiver functions (RFs) from P and PP phases and made Common Conversion Point stacks to image the structures in the slab and forearc wedge down to a depth of 100 km. We have identified the oceanic slab Moho on several E-W and N-S profiles at 40 to 60 km depth beneath the array and several discontinuities above the slab in the forearc. These profiles also show a large low-velocity zone beneath the northern half of the array in the forearc. In addition, we are using a 2.5D finite difference teleseismic waveform tomography technique described in Roecker et al. (2010) to image the crust and upper mantle beneath that part of the Chilean Andes occupied by the IMAD array and the earlier TIPTEQ deployment of Rietbrock et al. (2005). While the technique does not require any kind of formal source deconvolution, in sparse deployments we can apply this technique in an RF type migration by normalizing medium sensitivities. Both these techniques will improve our imaging of the down-dip limit of the seismogenic zone, forearc wedge and

  19. The relation of the mid-Tertiary coastal magmatic belt in south-central Chile to the late Oligocene increase in plate convergence rate

    Jorge Muñoz


    Full Text Available The mid-Tertiary Coastal Magmatic Belt in south-central Chile, which crops out both in the Central Valley and, south of 41°S, in the Coastal Cordillera as far west as the Pacific coast, formed when the locus of Andean magmatic activity expanded, both to the west and to the east relative to its previous and current location in the Main Cordillera. This expansion of the magmatic arc occurred in conjunction with a regionally widespread episode of late Oligocene to Miocene extension which thinned the crust below the proto-Central Valley in south-central Chile and generated sedimentary basins west of, within, and east of the Main Cordillera. The extrusive rocks of the mid-Tertiary Coastal Magmatic Belt are interbedded with the late Oligocene to Miocene continental and marine sediments deposited in these basins, and forty-seven of the fifty new and previously published age determinations for these rocks are within the time period 29 Ma (late Oligocene to 18.8 Ma (early Miocene. The initiation of extension, basin formation and the westward migration of magmatic activity coincides closely to the beginning, in the late Oligocene, of the current period of both high convergence rate (>10 cm/yr and less oblique convergence, which together resulted in an approximately three-fold increase in trench-normal convergence rate between the Nazca and South American plates. Extension continued, along with a transient steepening of subduction angle as indicated by the westward migration of the volcanic front during the formation of the mid-Tertiary Coastal Magmatic Belt, during an approximately 10 million year period after the trench-normal convergence rate tripled across the Nazca and South American plate boundary. The mid-Tertiary Coastal Magmatic Belt includes igneous rocks chemically similar to modern Andean arc magmas, as well as rocks with ocean island basalt chemical affinities characterised by lower Ba/La (+5. The latter formed by melting of mantle

  20. Positive interactions between alpine plant species and the nurse cushion plant Laretia acaulis do not increase with elevation in the Andes of central Chile.

    Cavieres, Lohengrin A; Badano, Ernesto I; Sierra-Almeida, Angela; Gómez-González, Susana; Molina-Montenegro, Marco A


    In alpine habitats, positive interactions among plants tend to increase with elevation as a result of altitudinal increase in environmental harshness. However, in mountains located in arid zones, lower elevations are also stressful because of scarce availability of water, suggesting that positive interactions may not necessarily increase with elevation. Here we analysed the spatial association of plant species with the nurse cushion plant Laretia acaulis at two contrasting elevations, and monitored the survival of seedlings of two species experimentally planted within and outside cushions in the semiarid Andes of central Chile. Positive spatial associations with cushions were more frequent at lower elevations. Species growing at the two elevations changed the nature of their association with cushions from neutral or negative at higher elevations to positive at lower elevations. Survival of seedlings was higher within cushions, particularly at lower elevations. The increased facilitation by cushions at lower elevations seems to be related to provision of moisture. This result suggests that cushion plants play a critical role in structuring alpine plant communities at lower elevations, and that climatic changes in rainfall could be very relevant for persistence of plant communities. PMID:16390419

  1. Application of stable isotopes to evaluate groundwater recharge of a coastal aquifer in North-Central Chile and its role in vegetation dynamics

    The understanding of the water sources for plant growth is one of the key elements to evaluate the present and long term primary productivity in arid ecosystems. We use stable isotope tools to evaluate the recharge mechanisms in a coastal aquifer located in the arid zone of north-central Chile. The main water sources in the study area, fog, rain and groundwater, were isotopically characterized over a decade. The isotope data confirmed that fog does not play any role in groundwater recharge. The water table and isotope data showed that during low water conditions (dry periods), the aquifer is maintained primarily by water recharged in the higher part of the Romeral basin. During high water table conditions (wet periods), recharge associated with local precipitation becomes a significant source of groundwater recharge. The aquifer responded very fast to rains with amounts over the average level for precipitation (like El Nino conditions), while no recharge was detected with precipitation events lower than the average value for precipitation. The recharge pattern can also influence the behavior of plants characterized by a dimorphic root systems than can perform hydraulic redistribution. Part of the fast recharge of the aquifer could be related to this water redistribution. (author)

  2. Patrón de asentamiento durante el periodo Alfarero en la cuenca de Santiago, Chile Central: Una mirada a la escala local Settlement pattern during the early Ceramic period in the Santiago basin, Central Chile: A view at the local level

    Luis Cornejo


    Full Text Available Se presentan y discuten la metodología y los resultados de prospecciones superficiales de alta intensidad realizadas en el extremo meridional de la cuenca de Santiago, poniendo énfasis en una escala de análisis hasta ahora no considerada en la arqueología de Chile Central, que es el estudio sistemático de la localidad. Los resultados muestran que el patrón de asentamiento denota una alta concentración de ocupaciones domésticas del periodo Alfarero temprano, continuadas más tardíamente pero con menor intensidad. Estas ocupaciones resultan estar vinculadas a la disponibilidad en esta localidad de recursos de aguas superficiales y reflejarían una forma de ocupar el espacio definida por unidades domésticas dispersas que en sus cercanías tendrían a otras unidades sociales no necesariamente vinculadas socialmente.This paper presents the methodology and results of intensive surface surveys carried out in the southern Santiago Basin, focused on the locality, a scale of analysis not previously undertaken in archeological studies of Central Chile. The settlement pattern point out to a high concentration of Early Ceramic Period domestic occupations, followed by less intense occupations during the Late Ceramic Period. These occupations were linked to the availability in this locality of surface water resources and reflect a way of occupying space defined by scattered domestic units , in whose vicinity were other domestic units, although not necessarily connected socially.

  3. Deformación frágil de los depósitos neógenos de la cuenca de Navidad (Cordillera de la Costa, 34°S, Chile central Brittle deformation of the Neogene deposits of the Navidad Basin (Coastal Cordillera, 34°S, central Chile

    Alain Lavenu


    Full Text Available En la cuenca neógena de Navidad, situada en la Cordillera de la Costa de Chile central (~34°S, se identificaron una serie de deformaciones frágiles que fueron generadas durante el Mioceno Tardío y el Plioceno. A partir del análisis numérico de planos de microfallas y sus estrías, se determinaron las direcciones principales de los esfuerzos producidos por diversos eventos tectónicos extensionales y compresivos. Los resultados obtenidos en la cuenca de Navidad permiten concluir que durante el Mioceno Tardío-Plioceno Temprano se produjo una extensión con dirección desconocida. Posteriormente, una deformación extensional, de dirección aproximada este-oeste, afecta a esta zona durante todo el Plioceno. Durante esta época se produce un corto pulso tectónico compresivo de dirección este oeste. A pesar de este evento compresivo la cuenca marina de Navidad se desarrolló esencialmente en un ambiente tectónico extensional durante todo el NeógenoIn the Neogene Navidad Basin, located in the Coastal Range of central Chile (34°S, a series of brittle deformations generated during the Late Miocene and Pliocene, were observed. Based on the numerical analysis of microfault planes and their slickensides, the main stress directions, caused by various extensional and compressive tectonic events, were determined. Results obtained in the Navidad Basin indicate that an extension of unknown direction occurred during the Late Miocene-Early Pliocene. Thereafter, extensional deformation orientated approximately east-west, affected this zone during the whole of the Pliocene. During this epoch a short east-west compressive pulse occurred. In spite of this compressive event, the marine Navidad Basin developed essentially in an extensional tectonic regime during the entire Neogene

  4. Talla de madurez y época de desove de la reineta (Brama australis Valenciennes, 1836 en la costa central de Chile Maturity size and spawning time of the Pacific pomfret (Brama australis Valenciennes, 1836 in the central coast of Chile

    Elson Leal


    Full Text Available La reineta (Brama australis adquiere cada vez mayor importancia en los desembarques de la pesca artesanal, no obstante, es escasa la información que existe acerca de su biología básica, particularmente sobre su dinámica reproductiva. En este trabajo se determina la época principal de desove de B. australis en la costa central de Chile y la talla de madurez (TM, para lo cual se analizó un total de 1061 individuos capturados frente a Lebu (37º37'S-73º40'W, entre enero y septiembre de 2001. El análisis macroscópico de los ovarios, mostró ejemplares sexualmente maduros durante todo el período de muestreo. El Indice Gonadosomático (IGS presentó fluctuaciones que indican un extenso período de desove, con un máximo invernal (junio-agosto. La TM se calculó a partir del método de longitud del 50% de hembras maduras a los 36,9 cm longitud horquilla (LH, con intervalo de confianza entre 35,3 y 37,8 cm y en 39 cm LH mediante el método del Incremento Relativo del IGS (IR.IGS. Debido a que las capturas ocurrieron principalmente en ejemplares sobre 39 cm LH, la flota estaría extrayendo mayoritariamente peces madurosLandings of Pacific pomfret (Brama australis is acquiring an increasing importance to the Chilean artisanal fishery. However, lack of information regarding its basic biology, in particular, reproductive dynamics, still persists. In this work we determine the spawning season of B. australis in the central coast of Chile and the length of maturity (LM. A total of 1061 individuals captured in the coastal zone of Lebu (37°37'S-73°40'W, Chile, between January and September 2001, were analyzed. Macroscopic analysis of ovaries, showed sexually mature individuals throughout the sampling period. Gonadosomatic Index (IGS showed fluctuations indicative of extensive spawning periods, with a maximum in the austral winter season (June-August. LM of females was estimated with the length at 50% maturity method, in 36.9 cm fork length (LH, with

  5. Effects of massive wind power integration on short-term water resource management in central Chile - a grid-wide study

    Haas, J.; Olivares, M. A.; Palma, R.


    In central Chile, water from reservoirs and streams is mainly used for irrigation and power generation. Hydropower reservoirs operation is particularly challenging because: i) decisions at each plant impact the entire power system, and ii) the existence of large storage capacity implies inter-temporal ties. An Independent System Operator (ISO) decides the grid-wide optimal allocation of water for power generation, under irrigation-related constraints. To account for the long-term opportunity cost of water, a future cost function is determined and used in the short term planning. As population growth and green policies demand increasing levels of renewable energy in power systems, deployment of wind farms and solar plants is rising quickly. However, their power output is highly fluctuating on short time scales, affecting the operation of power plants, particularly those fast responding units as hydropower reservoirs. This study addresses these indirect consequences of massive introduction of green energy sources on reservoir operations. Short-term reservoir operation, under different wind penetration scenarios, is simulated using a replica of Chile's ISO's scheduling optimization tools. Furthermore, an ongoing study is exploring the potential to augment the capacity the existing hydro-power plants to better cope with the balancing needs due to a higher wind power share in the system. As reservoir releases determine to a great extent flows at downstream locations, hourly time series of turbined flows for 24-hour periods were computed for selected combinations between new wind farms and increased capacity of existing hydropower plants. These time series are compiled into subdaily hydrologic alteration (SDHA) indexes (Zimmerman et al, 2010). The resulting sample of indexes is then analyzed using duration curves. Results show a clear increase in the SDHA for every reservoir of the system as more fluctuating renewables are integrated into the system. High

  6. Hábitos alimentarios de Dosidicus gigas (D' Orbigny, 1835 (Cephalopoda: Teuthoidea frente a la costa centro-sur de Chile Feeding habits of Dosidicus gigas (D'Orbigny, 1835 (Cephalopoda: Teuthoidea in the central-south coast off Chile



    Full Text Available Se estudiaron los hábitos alimentarios del calamar rojo Dosidicus gigas (D'Orbigny, 1835 frente a la costa de Chile centro-sur, durante el invierno del año 2005. Se examinaron un total de 52 estómagos, en todos los cuales había contenido alimentario. Los ejemplares provenían de pescas efectuadas por la flota arrastrera industrial que opera entre 36°39' S y 38°55'S sobre la merluza común Merluccius gayi (Guichenot 1848 y a una profundidad media de 290 m sobre la plataforma continental. Para la descripción del espectro trófico, alimento principal y el establecimiento de las eventuales diferencias sexuales u ontogenéticas en la frecuencia de aparición de los ítemes presa, se utilizaron los métodos numérico, gravimétrico, de frecuencia de ocurrencia, índice de importancia relativa (IIR e índice de similitud porcentual (ISP. No se observaron diferencias sexuales ni ontogenéticas en la frecuencia de aparición de los ítemes presa. Los resultados muestran que D. gigas es un depredador oportunista, principalmente ictiófago, y secundariamente malacófago (incluye el canibalismo y carcinófago. Se discuten los eventuales motivos e implicancias de tal conductaA study on the feeding habits of the jumbo squid Dosidicus gigas (D'Orbigny, 1835 was carried out during the winter season 2005, in waters of the Chilean central and southern Pacific. A total of 52 jumbo squid stomachs from the fishing of the continental slope were collected and examined, in the Eighth and Ninth regions, between 36°40' S and 38°55'S, at an average depth of 290 m. To determine the trophic spectrum, the feeding preferences and the importance of the sex and ontogenetic condition in the diet, the numeric, gravimetric, frequency of occurrence methods, and the index of relative importance and dietary similarity were utilized. The frequency of the prey did not vary with relation to the sex and ontogenetic conditions, and was besides a hight trophic similarity in such

  7. Water Erosion Prediction Using the Revised Universal Soil Loss Equation (RUSLE in a GIS Framework, Central Chile Estimación de la Erosión Hídrica Empleando la Ecuación Universal de Pérdida de Suelo Revisada (RUSLE y SIG en Chile Central

    Carlos A Bonilla


    Full Text Available Soil erosion is a growing problem in Central Chile, particularly in coastal dry lands, where it can significantly decrease the productivity of rainfed agriculture and forestry. In this study, the Revised Universal Soil Loss Equation (RUSLE was integrated into a Geographic Information System (GIS, and used to evaluate the effects of different combinations of vegetative cover on soil erosion rates for Santo Domingo County in Central Chile. Implementing RUSLE in the GIS required a complete description of the county’s soils, climate, topography and current land use/land cover. This information was compiled in rasters of 25 x 25 m cells. RUSLE parameter values were assigned to each cell and annual soil loss estimates were generated on a cell by cell basis. Soil losses were estimated for the current and for three alternate scenarios of vegetative cover. Under current conditions, 39.7% of the county is predicted to have low erosion rates ( 1.1 t ha-1 yr-1. The remainder of the surface (10.2% is not subject to erosion. Under the recommended alternate scenario, 89.3% of the county is predicted to have low erosion rates, and no areas are affected by high soil loss, reducing soil erosion to a level that will not affect long term productivity. This paper describes how RUSLE was implemented in the GIS, and the methodology and equations used to evaluate the effects of the land use/land cover changes.La erosión hídrica es un problema creciente en la Zona Central de Chile, especialmente en el Secano Costero, donde reduce la productividad de los suelos agrícolas y forestales. En este trabajo se empleó la Ecuación Universal de Pérdida de Suelo Revisada (RUSLE integrada a un Sistema de Información Geográfica (GIS para evaluar el efecto de distintas combinaciones de cubierta vegetal en las tasas de erosión en la comuna de Santo Domingo, Chile. La implementación de RUSLE en el GIS requirió la caracterización de suelos, clima, relieve y uso actual del

  8. K-Ar geochronologic evidence for a triassic metamorphic event in the main Chiloe Island, south-central Chile

    Pioneers geological reconnaissance studies in the Chiloe Archipelago recognised a Palaeozoic metamorphic basement (Saliot, 1969; Watters and Fleming, 1972; Valenzuela, 1982; Valdivia, 1986). Currently in progress geologic studies (Munoz et al., 1999, Duhart et al., 2000; Antinao et al., 2000) interpreted these rocks as part of the Bahia Mansa Metamorphic Complex (Duhart et al., 2000), well exposed to the north and equivalent to the 'Serie Occidental' (Aguirre et al., 1972). Geochronologic data set indicate that this complex evolved during Devonian to Triassic times. In the main Chiloe Island, this metamorphic complex is mainly conform by metasedimentary and metavolcanic rocks covered by Tertiary sedimentary and volcanic rocks and Quaternary glacial, fluvial, estuarine, beach, eolian and fluvial deposits. According to north-west and north-south lineament observed in satellite images, regional magnetic maps and topographic features, the main Chiloe island have been divide in northern, central and southern segments (Munoz et al., 1999). These lineaments are interpreted as regional faults but their ages and cinematic are not well constrained. The central segment was interpreted as an uplifted tectonic block and recent studies in the northern part of this segment have identified an intrusive body herein named as 'Metalqui Pluton'. Although the age of this pluton is unknown yet, Cretaceous intrusive rocks in the same tectonic setting of the Metalqui Pluton have been reported in the Valdivia area (Munizaga et al., 1988; Duhart et al., 1998). Previous U-Pb radiometric ages for detrital zircons from pelitic schists in the northern segment indicated a maximum sediment deposition age during Early to Middle Devonian (Duhart et al., 1999). Also, Triassic K-Ar and 40Ar/39Ar ages have been determined for the main metamorphic and tectonic event. This contribution report Triassic K-Ar ages for the central segment and discuss their regional significance (au)

  9. Estudio hidrogeoquímico en la cuenca altiplánica de Pampa Lirima, Andes Centrales (Chile)

    Achurra, Luciano; Custodio Gimena, Emilio; Aguirre, Igor; Arcos, Rodrigo; Clavero, Jorge


    La cuenca de Pampa Lirima se ubica en el límite occidental del Altiplano. Las cumbres y zonas elevadas (4200-5800 msnm) de la cuenca se componen de rocas volcánicas del Oligoceno a Plioceno, donde localmente se desarrollan acuíferos colgados y acuitardos en los sectores afectados por alteración hidrotermal. En la zona central más deprimida (4000-4200 msnm) la cuenca está rellena de depósitos aluviales y pluvioglaciales, que forman un acuífero intergranular libre y artesiano en sectores pun...

  10. Aftershock seismicity and tectonic setting of the 2015 September 16 Mw 8.3 Illapel earthquake, Central Chile

    Lange, Dietrich; Geersen, Jacob; Barrientos, Sergio; Moreno, Marcos; Grevemeyer, Ingo; Contreras-Reyes, Eduardo; Kopp, Heidrun


    Powerful subduction zone earthquakes rupture thousands of square kilometres along continental margins but at certain locations earthquake rupture terminates. To date, detailed knowledge of the parameters that govern seismic rupture and aftershocks is still incomplete. On 2015 September 16, the Mw 8.3 Illapel earthquake ruptured a 200 km long stretch of the Central Chilean subduction zone, triggering a tsunami and causing significant damage. Here, we analyse the temporal and spatial pattern of the coseismic rupture and aftershocks in relation to the tectonic setting in the earthquake area. Aftershocks cluster around the area of maximum coseismic slip, in particular in lateral and downdip direction. During the first 24 hr after the main shock, aftershocks migrated in both lateral directions with velocities of approximately 2.5 and 5 km hr-1. At the southern rupture boundary, aftershocks cluster around individual subducted seamounts that are related to the downthrusting Juan Fernández Ridge. In the northern part of the rupture area, aftershocks separate into an upper cluster (above 25 km depth) and a lower cluster (below 35 km depth). This dual seismic-aseismic transition in downdip direction is also observed in the interseismic period suggesting that it may represent a persistent feature for the Central Chilean subduction zone.

  11. Estabilidad temporal de las infracomunidades de parásitos en la borrachilla Scartichthys viridis (Valenciennes, 1836 (Pisces : Blenniidae en la costa central de Chile Temporal stability in parasite infracommunities of the blenny Scartichthys viridis(Valenciennes, 1836 (Pisces: Blenniidae on the central coast of Chile



    Full Text Available Se comparan las infracomunidades de parásitos de la borrachilla Scartichthys viridis (Pisces: Blenniidae de tres muestras tomadas en un lapso de 17 meses, entre 1999 y 2001, desde pozas intermareales vecinas a Las Cruces (33°27' S, 71°37' O, Chile central. El objetivo es averiguar si la riqueza, diversidad, abundancia y composición de las infracomunidades de parásitos son persistentes o no en el tiempo ontogenético y cronológico. Se recolectaron 10 taxa parasitarios en cerca del 89 % de los 63 huéspedes examinados, de los cuales ocho eran metazoarios. La búsqueda de protozoos se realizó sólo en los últimos 2 años. El 75 % de los ocho taxa de metazoos ocurrieron en los tres años, uno no estuvo presente en un año, y otro fue encontrado solamente en un año. La mayoría de los huéspedes examinados albergaba protozoos parásitos. La prevalencia de los protozoos Cryptobia sp. fue alta para ambos años, y menor en Trichodina sp. La longitud total de los huéspedes era un predictor relevante de las variaciones en la riqueza, abundancia, diversidad y composición infracomunitaria en el conjunto de los tres años. En cambio, el año de muestreo no lo fue, en particular al comparar entre huéspedes de similar longitud total. Estos resultados son similares a los encontrados en infracomunidades de parásitos de otras especies de peces en Chile, en que hay baja variabilidad en las propiedades agregadas de las infracomunidades en el tiempo cronológico. Se discute acerca de la extensión relativa del tiempo ontogenético en contraste al tiempo cronológico al ser probablemente ambos de importancia en las características de las infracomunidades, y se propone que se explore la medida en la cual estos resultados constituyen un patrón.Parasite infracommunities of the blenny Scartichthys viridis (Pisces: Blenniidae are compared among three samples taken within a 17-month period during three consecutive years (1999-2001, from intertidal pools at

  12. Karyotypic polymorphism and evolution within and between the Liolaemus monticola (Iguanidae "northern 2n = 38-40" chromosome race populations in central Chile Polimorfismo cromosómico y evolución intra e inter poblacional de la raza cromosómica "Norte 2n = 28-40" de Liolaemus monticola (Iguanidae en Chile Central



    Full Text Available Chromosomal genotypes were scored from 359 Liolaemus monticola lizards of the "northern, 2n = 38-40" chromosomal race from 21 locality samples between the Maipo (and one of its tributaries and the Aconcagua (and one of its tributaries ribers, plus a sample from the interracial hybridization zone, and some representative locality samples of the "southern 2n = 34" and the "multiple fission 2n = 42-44" chromosomal races for comparisons. The first seven variable chromosomal pairs were coded as Mendelian genotypes and statistically summarized by several clustering and population genetic algorithms. Spatial and temporal differentiation was assessed by chromosome frequencies, chromosomal diversity and heterozygosity. While no differentiation was found for diversity in the "northern 2n = 38-40" race, chromosomal frequencies and heterozygosity showed significant spatial differentiation that permit distinguishing between the coastal, Andean and transversal mountain range populations. The sample of Cuesta Chacabuco may represent a hybrid zone between the other two range samples. The origin of the chromosomal rearrangements, the population cytogenetics, and the recombination patterns resulting from chromosomal heterozygosity are compared in these chromosomal races, thus expanding the geographical area. These patterns are discussed with respect to the evolution of this complex in Chile and the importance of the riverine barriers in central ChileSe cuantificaron los "genotipos" cromosómicos para 359 lagartijas de 21 muestras poblacionales de la raza "Norte, 2n = 38-40" comprendida entre los ríos: río Maipo y uno de sus afluentes el río Yeso y río Aconcagua (y uno de sus afluentes el río Juncal. Con fines comparativos agregamos una muestra de la zona de hibridación interracial, algunas muestras representativas de la raza "Sur 2n = 34" y una de la raza "múltiples fisiones 2n = 42-44". Los siete primeros pares cromosómicos variables fueron codificados

  13. Fission track thermochronology of Neogene plutons in the Principal Andean Cordillera of central Chile (33-35°S): Implications for tectonic evolution and porphyry Cu-Mo mineralization Termocronología mediante trazas de fision de plutones neógenos en la Cordillera Principal Andina de Chile central (33-35°S): Implicancias para la evolución tectónica y mineralización de pórfidos de Cu-Mo

    Víctor Maksaev; Francisco Munizaga; Marcos Zentilli; Reynaldo Charrier


    Apatite fission track data for Miocene plutons of the western slope of the Principal Andean Cordillera in central Chile (33-35°S) define a distinct episode of enhanced crustal cooling through the temperature range of the apatite partial annealing zone (~125-60°C) from about 6 to 3 Ma. This cooling episode is compatible with accelerated exhumation of the plutons at the time of Pliocene compressive tectonism, and mass wasting on the western slope of the Principal Andean Cordillera in central Ch...

  14. Multiscale upwelling forcing cycles and biological response off north-central Chile Ciclos multiescala en el forzamiento de la surgencia y respuesta biológica en el centro-norte de Chile



    Full Text Available The physical forcing of the upwelling along the subtropical west coasts of the continents encompasses a broad range of time scales which shape both phytoplankton biomass (Chl-a and primary productivity (carbon fixation changes over any given time interval. The narrow continental shelf and the steep alongshore orography off north-central Chile provide for a unique combination of year-round, upwelling-favorable winds with quasi-weekly upwelling pulses associated with atmospheric coastal-trapped disturbances (coastal lows. This variability is modulated by intraseasonal oscillations in the depth of the thermo/nutricline, produced by coastal-trapped waves in the ocean, upon which annual (seasons and interannual (ENSO cycles are superimposed. During coastal field experiments off Cruz Grande bay (29º S, carried on in November 1987 and 1988 (opposite extremes of the ENSO cycle, mean changes of the phytoplankton-integrated Chl-a (B and carbon fixation rate (PP from the active to the relaxed phases of the local upwelling forcing cycle (phyto-pattern were characterized. Those data were contrasted against similar ones reported off Punta Lengua de Vaca (Coquimbo, 30º S and off Mejillones peninsula (Antofagasta, 23º S, encompassing different seasons and phases of intraseasonal and interannual (ENSO cycles from 1992 to 1997. A "warm" phyto-pattern was schematically characterized by a significant increase in B and a quasi-steady evolution of PP from the active to the relaxed phases of one complete upwelling event. Conversely, relative small changes in B and a significant increase in PP characterized a "cold" phyto-pattern. It is proposed here that the ENSO "cold/warm" signal may be offset by more than one opposite "thermal" condition (seasonal and/or intraseasonal in defining a "warm" or "cold" phyto-pattern associated with a particular cycle of the local upwelling forcingEl forzamiento físico de la surgencia a lo largo de las costas occidentales de los

  15. Satellite-measured interannual variability of turbid river plumes off central-southern Chile: Spatial patterns and the influence of climate variability

    Saldías, Gonzalo S.; Largier, John L.; Mendes, Renato; Pérez-Santos, Iván; Vargas, Cristian A.; Sobarzo, Marcus


    Ocean color imagery from MODIS (Moderate Resolution Imaging Spectroradiometer) onboard the Aqua platform is used to characterize the interannual variability of turbid river plumes off central-southern Chile. Emphasis is placed on the influence of climate fluctuations, namely El Niño Southern Oscillation (ENSO), the Pacific Decadal Oscillation (PDO), and the Antarctic Oscillation (AAO). Additional satellite data on wind, boat-based hydrographic profiles, and regional climate indices are used to identify the influence of climate variability on the generation of anomalous turbid river plumes. The evolution of salinity at a coastal station on the 90 m isobath between the Itata and Biobío Rivers shows a freshwater surface layer with salinity < 32.5 and 5-10 m thick during major plume events in 2002, 2005 and 2006. Surface salinity minima are correlated with peaks in turbidy from the normalized water leaving radiance at 555 nm (nLw(555)), both representing turbid river plumes. EOF analysis reveals that major turbid plume events occurred primarily during warm phases of the ENSO and PDO, and negative phases of the AAO, when storm tracks are further north. Anomalously large turbid plumes extend long distances offshore (∼ 70-80 km), and individual plumes coalesce into a continuous plume along the coast that covers the entire continental shelf. Season-specific correlation analyses reveal an increased influence of the AAO on river plumes south of Punta Lavapié in spring-summer (negative correlation). North of this major cape, ENSO and PDO indices have a dominant influence on plumes with positive correlations with the nLw(555) signal in winter (and negative in summer). We discuss the biogeochemical implications of plume events and the importance of long-term and high-resolution ocean color observations for studying the temporal evolution of river plumes.

  16. Seasonal mercury concentrations and δ15N and δ13C values of benthic macroinvertebrates and sediments from a historically polluted estuary in south central Chile

    The Lenga Estuary is one of the most industrialized sites in south central Chile where the historic operation of chlor-alkali plants resulted in large quantities of mercury (Hg) being deposited into the estuary. This historical contamination may still represent a risk to the biota in the estuary. To investigate this four macroinvertebrates, Neotrypaea uncinata (ghostshrimp), Elminius kingii (barnacle), Hemigrapsus crenulatus (shore crab) and Perinereis gualpensis (ragworm) were collected seasonally from three different sites in the Lenga Estuary and one in a reference estuary (Tubul Estuary), and analyzed for Hg and stable isotopes (δ15N and δ13C). Mercury concentrations in Lenga sediments ranged from 0.4 ± 0.1 to 13 ± 3 mg/kg, while those in Tubul sediments ranged from 0.02 ± 0.01 to 0.07 ± 0.09 mg/kg. Total Hg concentrations of invertebrates were significantly different between estuaries (p 0.05). In contrast, organic Hg concentrations were different by species and season with shore crab muscle tissues exhibiting the greatest percent difference. Site-specific relationships demonstrated that total Hg concentrations in ragworm best reflected the total Hg sediment mercury concentrations. Signatures of δ13C were correlated to the organic Hg % rather than total Hg. This suggests that organic Hg concentrations in these species were related to the carbon sources. -- Highlights: ► Hg in sediments and biota from Lenga Estuary were elevated compared to nearby estuary. ► Invertebrates showed interspecific and seasonal differences in terms of organic Hg %. ► Total Hg levels in the ragworm best reflect Hg sediment gradient in Lenga Estuary. ► Interspecific variation in δ13C signatures indicated different feeding modes. ► Organic forms of Hg in invertebrates were mainly related to the carbon sources.

  17. Biases in determining the diet of jumbo squid Dosidicus gigas (D' Orbigny 1835) (Cephalopoda: Ommastrephidae) off southern-central Chile (34°S-40°S)

    Ibáñez, Christian M.; Arancibia, Hugo; Cubillos, Luis A.


    The diet of jumbo squid ( Dosidicus gigas) off southern-central Chile is described to examine potential biases in the determination of their main prey. Specimens were collected from catches using different fishing gear (jigging, trawl and purse-seine), from July 2003 to January 2004, and from December 2005 to October 2006. The stomach contents were analyzed in terms of frequency of occurrence, number, and weight of prey items and the diet composition was analyzed using Detrended Correspondence Analysis. In the industrial purse-seine fleet for jack mackerel ( Trachurus murphyi), the dominant prey of D. gigas was T. murphyi. In the industrial mid-trawl fishery for Patagonian grenadier ( Macruronus magellanicus), the dominant species in the diet of D. gigas was M. magellanicus. Similarly, Chilean hake ( Merluccius gayi) was the main prey in the diet of D. gigas obtained in the industrial trawl fishery for Chilean hake; and, in both artisanal fisheries (purse-seine for small pelagics and jigging), small pelagic fish and D. gigas were the main prey in the stomach contents of D. gigas. Cannibalism in D. gigas varied between different fleets and probably is related to stress behavior during fishing. The Detrended Correspondence Analysis ordination showed that the main prey in the diet of D. gigas is associated with the target species of the respective fishery. Consequently, biases are associated with fishing gear, leading to an overestimate in the occurrence of the target species in the diet. We recommend analyzing samples from jigging taken at the same time and place where the trawl and purse-seine fleets are operating to avoid this problem, and the application of new tools like stable isotope, heavy metal, and fatty acid signature analyses.

  18. Recruitment Dynamics of the Relict Palm, Jubaea chilensis: Intricate and Pervasive Effects of Invasive Herbivores and Nurse Shrubs in Central Chile.

    Fleury, Marina; Marcelo, Wara; Vásquez, Rodrigo A; González, Luis Alberto; Bustamante, Ramiro O


    Shrubs can have a net positive effect on the recruitment of other species, especially relict species in dry-stressful conditions. We tested the effects of nurse shrubs and herbivory defoliation on performance (survival and growth) of nursery-grown seedlings of the largest living palm, the relict wine palm Jubaea chilensis. During an 18-month period, a total of more than 300 seedlings were exposed to of four possible scenarios produced by independently weakening the effects of nurse shrubs and browsers. The experiment followed a two-way fully factorial design. We found consistent differences in survival between protected and unprotected seedlings (27.5% and 0.7%, respectively), and herbivory had a dramatic and overwhelmingly negative effect on seedling survival. The invasive rabbit (Oryctolagus cuniculus) is clearly creating a critical bottleneck in the regeneration process and might, therefore, partially explain the general lack of natural regeneration of wine palms under natural conditions. Apparently biotic filters mediated by ecological interactions are more relevant in the early stages of recruitment than abiotic, at least in invaded sites of central Chile. Our data reveal that plant-plant facilitation relationship may be modulated by plant-animal interactions, specifically by herbivory, a common and widespread ecological interaction in arid and semi-arid environments whose role has been frequently neglected. Treatments that protect young wine palm seedlings are mandatory to enable the seedlings to attain a height at which shoots are no longer vulnerable to browsing. Such protection is an essential first step toward the conservation and reintroduction of this emblematic and threatened species. PMID:26218100

  19. Cenozoic tholeiitic volcanism in the Colbún area, Linares Precordillera, central Chile (35º35'-36ºS

    Mario Vergara


    Full Text Available RESUMEN Volcanismo toleítico Terciario en el área de Colbún, Precordillera de Linares, Chile central (35º-35º36'S. En la Precordillera de Linares, Chile central (35º5'-36ºS, afloran rocas volcánicas, cuyas edades varían del Eoceno Superior al Mioceno Medio. Sobre la base de criterios estratigráficos y dataciones K-Ar y Ar-Ar, se han diferenciado dos unidades: 1- una Unidad Inferior (Eoceno Superior a Oligoceno Superior, con predominio de rocas volcánicas silíceas en la base y básicas en el nivel superior y 2- una Unidad superior (Mioceno Inferior a Medio, con basaltos afíricos y tobas soldadas riolíticas. Las características geoquímicas de las rocas volcánicas de Colbún, tales como bajos contenidos en K2O, razones MgO/FeO altas, patrones de REE planos, abundancia normalizada con respecto al MORB cercana a la unidad para los elementos Nb a Sc, razones isotópicas iniciales de Sr relativamente bajas (0.703575-0.704028 y relativamente altas de Nd (0.512919-0.513003, son consistentes con una afinidad toleítica y con un grado de contaminación cortical bajo en la evolución de los magmas parentales. Las relaciones isotópicas de Pb y el enriquecimiento en algunos elementos incompatibles, tales como K, Rb, Sr y Ba, sugieren un reciclamiento de material subductado de la placa de Nazca, el cual estuvo acompañado por un adelgazamiento cortical y el desarrollo de estructuras tipo calderas. Isotópicamente, las rocas de Colbún son las más primitivas de los Andes chilenos. Relaciones geoquímicas sugieren que estas rocas se emplazaron en un ambiente geotectónico de trasarco, intracontinental, postorogénico y extensional. Los magmas de Colbún evolucionaron, principalmente, por cristalización fraccional a partir de magmas primarios generados en el manto. Las semejanzas químicas e isotópicas presentadas por estas rocas emplazadas entre el Eoceno Superior y el Mioceno Medio sugieren que las fuentes y procesos, involucrados en su g

  20. Estimating glacier and snowmelt contributions to stream flow in a Central Andes catchment in Chile using natural tracers

    M. Rodriguez


    Full Text Available This paper presents a methodology for hydrograph separation in high elevation watersheds, which aims at identifying individual flow sources such as snow- and ice melt, rainfall and soil water. Daily summer and bi-daily spring water samples from the outlet of the Juncal River were analyzed for all major ions as well as stable water isotopes, δ18O and δ2H. Additionally, various water sources such as rain, springs, snow- and glacial melt were sampled throughout the catchment. A principal component analysis (PCA was performed in order to reduce the dimensionality of the problem. Potential sources were identified in a two-component U space that explains 77% of variability. Hydrograph separation (HS was performed through three models: (i Isotopic model, (ii Mixing–PCA model, and (iii Informative–Bayesian model, with very similar results in each case. At the Juncal River outlet, summer flows were composed by at least 50% of water originating in highly glaciarized headwaters in 2011–2012 (a dry period in the Central Andes. Autumn and winter flows were highly influenced by soil water and affect total annual discharge. Before the high flow season, snow melt accounted for approximately 25% of streamflow, However during summer, when streamflow was highest, snowmelt contribution was minimal, while glacier melt and soil water were the most important sources.

  1. Freezing resistance varies within the growing season and with elevation in high-Andean species of central Chile.

    Sierra-Almeida, Angela; Cavieres, Lohengrin A; Bravo, León A


    Predicted increases in the length of the growing season as a result of climate change may more frequently expose high-elevation plants to severe frosts. Understanding the ability of these species to resist frosts during the growing season is essential for predicting how species may respond to changes in temperature regimes. Here, we assessed the freezing resistance of 24 species from the central Chilean Andes by determining their low temperature damage (LT(50)), ice nucleation temperature (NT), freezing point (FP) and freezing resistance mechanism (i.e. avoidance or tolerance). The Andean species were found to resist frosts from -8.2 to -19.5 degrees C during the growing season, and freezing tolerance was the most common resistance mechanism. Freezing resistance (LT(50)) varied within the growing season, decreasing towards the end of this period in most of the studied species. However, the FP showed the opposite trend. LT(50) increased with elevation, whilst FP was lower in plants from lower elevations, especially late in the growing season. Andean species have the potential to withstand severe freezing conditions during the growing season, and the aridity of this high-elevation environment seems to play an important role in determining this high freezing resistance. PMID:19210722

  2. Using fecal profiles of bile acids to assess habitat use by threatened carnivores in the Maulino forest of central Chile Empleo del perfil de ácidos biliares fecales para evaluar uso del hábitat por carnívoros amenazados en el bosque maulino de Chile central



    Full Text Available The distribution and habitat use by carnivores can be assessed by studying their tracks or feces. If these methods are to be used confidently, they should not only unequivocally discriminate among species, but should also render the same patterns of spatial distributions. We assessed the fulfillment of these requirements with five carnivores inhabiting the Maulino forest of central Chile: Galictis cuja, Oncifelis guigna, Pseudalopex culpaeus, Pseudalopex griseus, and Puma concolor. Fecal bile acid thin layer chromatographic profiles were assessed, and shown to be species-specific, invariant within samples of a given individual and among individuals of a given species, but consistently different across species. The spatial distribution of feces in mixed stands of native forests and exotic pine plantations in the coastal Maule region of central Chile was compared with the expected distribution according to habitat offer, and also with the expected distribution based on earlier track records. The results revealed that Pseudalopex culpaeus makes extensive use of pine plantations; Oncifelis guigna prefers native forests, and Pseudalopex griseus thrives in pine plantations, native forests, and patches of native forest, in proportion to habitat availability. Results from scat distribution were similar to those obtained by tracks records. Feces and tracks were thus useful indicators of habitat use by carnivores, and could be used complementarily to study species with conservation problemsEl uso del hábitat por carnívoros puede ser examinado a partir de la distribución de sus huellas y fecas. Para que ambas aproximaciones sean usadas en forma segura y complementaria, ellas deberían no solamente discriminar inequívocamente entre especies, sino que también deberían entregar la misma información sobre los patrones de distribución espacial. Analizamos el cumplimiento de estos requisitos con cinco especies de carnívoros en el bosque maulino de Chile

  3. Evolución tectónica, paleogeográfica y metalogénica durante el Cenozoico en los Andes de Chile norte y central e implicaciones para las regiones adyacentes de Bolivia y Argentina Tectonic, paleogeographic, and metallogenic evolution during the Cenozoic in the Andes of Central and Northern Chile and implication for the adjacent regions of Bolivia and Argentina

    Reynaldo Charrier


    Full Text Available La orogenia incaica dio origen a un importante relieve en el Eoceno Medio, el que se concentró en el ámbito del arco magmático precedente, la Cordillera Incaica. Este relieve positivo de orientación NNE se extendió desde el sur de Perú hasta la región central de Chile y separó dos dominios paleogeográficos que tuvieron evoluciones diferentes durante el resto del Cenozoico. El dominio occidental se caracterizó por el predominio de procesos de erosión y sedimentación. En el dominio oriental también existieron importantes episodios de erosión que originaron depósitos que se encuentran en la vertiente oriental de la cadena en la actualidad y presentan una cronología comparable con la de los depósitos del dominio occidental. Sin embargo, la evolución se caracterizó por presentar, a partir del Eoceno Tardío, diferencias al norte y sur de los ~27ºS. Al norte de esa latitud, en el ámbito del Altiplano-Puna, el arco magmático se mantuvo aproximadamente en la misma posición, coincidente con la del arco actual, y estuvo bordeado por una cuenca de antepaís de retroarco; mientras que, al sur de ~27ºS, se desarrollaron sucesivos arcos magmáticos con una marcada migración hacia el este. El arco magmático del Eoceno Tardío al Oligoceno Tardío - Mioceno Temprano se caracterizó por el desarrollo de una amplia cuenca extensional de intra-arco, la cuenca de Abanico. En esta cuenca se acumularon hasta 3.000 m de rocas volcánicas, volcaniclásticas y, subordinadamente, sedimentarias. A partir del límite oligoceno-mioceno, tuvo lugar un nuevo evento compresivo a lo largo de todo el orógeno que rejuveneció el núcleo de la Cordillera Incaica e invirtió la cuenca de Abanico permitiendo la generación de abundantes depósitos sintectónicos a ambos lados de los nuevos relieves. El inicio de este evento coincide con la orogenia pehuenche, los pulsos compresivos se mantuvieron hasta el Plioceno Temprano. En el Mioceno Temprano a Medio

  4. Un modelo de la historia de la vegetación de la Cordillera de La Costa de Chile central-sur: la hipótesis glacial de Darwin A model for the history of vegetation of the Coastal Range of central-southern Chile: Darwin's glacial hypothesis



    Full Text Available En Chile central-sur, entre los paralelos 37 y 43º S, existen comunidades aisladas de coníferas y tundras magallánicas, cuya distribución principal es altoandina y/o de latitudes altas. De acuerdo a Darwin (1859, en general, estas "islas" corresponderían a los remanentes de poblaciones glaciales, que ocuparon sitios de menor altitud y latitudes más bajas, durante el avance de los hielos. Se desprende de esta hipótesis que, a lo largo de Chile, se habrían producido desplazamientos de la flora austral y andina hacia el Valle Longitudinal, durante la última glaciación, y en sentido inverso, durante el Tardiglacial (14.600-10.000 14C años AP y Holoceno (después de 10.000 14C años AP. Considerando esta hipótesis, en este trabajo se analizan dos secuencias palinológicas, procedentes de las cimas de la Cordillera de la Costa de la Región de los Lagos (cordilleras de Nahuelbuta y de Sarao, y se correlacionan con registros publicados, tanto de otros sitios de cimas de cerros, como de sitios de baja altitud, todos ellos procedentes de las regiones de Los Lagos y de Los Canales. Los registros de las cimas de la Cordillera de La Costa, analizados en este estudio, muestran la siguiente secuencia cronológica: (1 El registro de la Cordillera de Sarao documenta, para el Holoceno temprano, a partir de 9.040 14C años AP, la colonización del elemento de tundras magallánicas y bosque norpatagónico con coníferas, aunque ambas formaciones alcanzan su máximo desarrollo en el Holoceno medio, sucedidas por el elemento de bosque norpatagónico-valdiviano, en el Holoceno tardío. (2 El registro de la Cordillera de Nahuelbuta muestra que la colonización de estos mismos elementos se produce, recién, en el Holoceno medio, alrededor de 5.430 14C años AP. Otros registros de polen de las cimas de la Cordillera de La Costa (Cordillera Pelada y de Piuchué muestran que el desarrollo de ambas formaciones se produjo en el Tardiglacial y Holoceno temprano

  5. Efecto del reemplazo de la vegetación nativa de ribera sobre la comunidad de macroinvertebrados bentónicos en arroyos de climas templados, Chile central Replacement effect of riparian native vegetation on benthic macroinvertebrates community in temperate climate streams, Central Chile

    Gabriela Mancilla


    Full Text Available El aporte de materia orgánica desde la vegetación ribereña es determinante en la estructura y complejidad de los sistemas fluviales; es identificado como el mayor aporte energético en ríos y una fuente importante de alimento para macroinvertebrados en arroyos de cabecera. No obstante, el paisaje ribereño ha sido altamente degradado por actividades humanas, lo que ha afectado la estructura y composición de las comunidades acuáticas. El presente estudio se desarrolló en Chile central (región del Biobío donde se concentra una intensa actividad forestal con especies exóticas. Se seleccionaron ríos de bajo orden (The organic matter from riparian vegetation is determined by the structure and complexity of streams. It presents a higher energetic input to streams as well as important source of food for macroinvertebrates in head streams. In spite of its importance, riparian landscape has been rapidly degraded by human activity, this affects structure and composition of the aquatic community. The present study was made in Central Chile (Biobio Region which has intensive forest activity with exotic species. Small streams were selected (< 3 order, because they are very particularly sensitive to changes in land use. The sites were grouped identified according to native forest land cover larger than 20% (group 1 and smaller than 20% (group 2. Significant differences (p< 0.05 in Plecoptera abundance (p < 0.05 were found between the two groups. Differences in trophic groups were significant for shredders and predators increased and gathering-collectors decreased their abundance, with native cover smaller than 20%. This showed the dependent on allochthonous material. The vegetation cover and community parameters correlations showed that Diversity (W increased with higher percentage of watershed covered by native vegetation and exotic species mix. Results suggest that a buffer conservation area of native riparian vegetation is necessary in streams

  6. Biomasa en Chile

    Nilsson Cifuentes, Gabriel; Rodríguez Monroy, Carlos


    El artículo presenta el desarrollo de la biomasa en Chile, dentro del complejo marco energético existente en el país, el cual, aún no logra potenciar e incentivar el desarrollo de energías renovables y depende fuertemente de los combustibles fósiles, acrecentando el riesgo latente de sufrir una crisis energética, en el mediano plazo, producto de la paulatina incorporación de nuevas centrales generadoras de energías, que satisfagan la creciente demanda energética pronosticada. Este ar...

  7. La fauna de caprélidos (Crustacea: Amphipoda: Caprellidea de la costa de Coquimbo, centro-norte de Chile, con una clave taxonómica para la identificación de las especies The caprellid fauna (Crustacea: Amphipoda: Caprellidea from the coast of Coquimbo, Northern-central Chile, with a taxonomic key for species identification



    Full Text Available Los caprélidos son comunes y abundantes en muchos hábitats litorales del ambiente marino. Sin embargo este grupo de anfípodos no ha sido muy bien estudiado en la costa chilena. El estudio de los caprélidos se ha visto dificultado por su gran variabilidad morfológica y el hecho de que la literatura así como los especímenes de los museos son difíciles de localizar. El objetivo de este estudio fue entregar las herramientas taxonómicas para la identificación de las especies de crustáceos caprélidos comunes en el centro-norte de la costa de Chile. Se muestrearon distintos hábitats (boyas, bolones intermareales, praderas de algas y fanerógamas marinas y se encontraron seis especies distintas de caprélidos: Caprellina longicollis (Nicolet, 1849, Caprella equilibra Say, 1818, C. scaura Templeton, 1836, C. verrucosa Boeck, 1871; Deutella venenosa Mayer, 1890 y Paracaprella pusilla Mayer, 1890. Caprella scaura, C. verrucosa y D. venenosa fueron muy abundantes sobre las algas, hidrozoos y briozoos asociados a boyas. Caprella equilibra, también presente en boyas, fue más abundante bajo piedras en zonas intermareales rocosas expuestas, donde también se encontraron ejemplares de D. venenosa y de P. pusilla. Caprella scaura también se encontró sobre algas rojas de las playas arenosas, especialmente sobre Gracilaria chilensis y sobre la fanerógama marina Heterozostera tasmanica, donde cohabitó junto a Caprellina longicollis. Paracaprella pusilla constituye una nueva cita para las costas pacíficas sudamericanas, siendo nueva para la fauna de Chile. La especie D. venenosa, que se cita por primera vez después de la descripción original de Mayer en el año 1890, es considerada una especie endémica de la costa central de ChileCaprellids are abundant in many littoral habitats of the marine environment. Nevertheless, this group of amphipods has been scarcely studied along the coast of Chile. The study of the Caprellidea is particularly

  8. New time-constraints on provenance, metamorphism and exhumation of the Bahía Mansa Metamorphic Complex on the Main Chiloé Island, south-central Chile Nuevas restricciones temporales sobre proveniencia, metamorfismo y exhumación del Complejo Metamórfico Bahía Mansa en la Isla Grande de Chiloé, centro-sur de Chile

    Paul Duhart; Alberto C Adriasola


    The Coastal Ranges in the western part of the Chiloé Archipelago represent an emerged forearc high at the subduction front of south-central Chile. Prior to the Cenozoic framework of the subducting Farallón and Nazca plates beneath the South American plate, the history of the metamorphic basement in the Coastal Ranges involves episodes of subduction and/or accretion of oceanic and ensialic material along the proto-Pacific margin of Gondwana. Along different segments of the Main Chiloé Island t...

  9. Depositación atmosférica de nitrógeno en un transecto valle longitudinal-cordillera de Los Andes, centro-sur de Chile Atmospheric deposition of nitrogen in a transect from the Central Valley to Cordillera de Los Andes, south-central Chile



    Full Text Available El aumento de las actividades agrícolas y ganaderas en el centro-sur de Chile puede producir elevadas emisiones de nitrógeno hacia la atmósfera (mayormente NH3. El amoniaco es transportado por corrientes de aire y depositado en el suelo y vegetación. El presente estudio evalúa la depositación atmosférica de compuestos nitrogenados (NO3- y NH4+ en la química de las precipitaciones en un transecto altitudinal de 66 km, desde los alrededores de la ciudad de Osorno (40º 35' S, 72º 57' O, 55 m de altitud hasta la cordillera de Los Andes, Parque Nacional Puyehue (40º 46' S, 72º 11' O, 1.120 m de altitud. En siete sitios, durante el período anual junio-1999 hasta mayo-2000, se registró la precipitación y mensualmente se colectaron muestras de agua para determinar: pH, conductividad y las concentraciones de NO3- y NH4+. La precipitación anual se incrementó desde 1.103 mm en la zona de Osorno hasta 6.799 mm en el sector Antillanca, Parque Nacional Puyehue. Los valores promedio anual del pH registraron escasa variación desde 6,3 en el valle central hasta 5,8 en la cordillera de Los Andes. La conductividad presentó los máximos valores en la proximidad de Osorno (22,9 myS cm-1 para descender a través del transecto en zonas intermedias y alcanzar en la Cordillera de los Andes un valor de 11,3 myS cm-1. Las concentraciones promedio de NO3-Nen la lluvia fluctuaron entre 52,3 myg L-1 en la zona agrícola-ganadera y 6,9 myg L-1 en los bosques del Parque Nacional Puyehue. Las concentraciones de NH4-N variaron entre 699,4 myg L-1 en el sector de Osorno y 37,8 myL-1 en la cordillera de Los Andes. Los valores de N-inorgánico poseen una marcada tendencia estacional en el sector agrícola, con valores máximos en primavera-verano y los mínimos en invierno. Las tasas anuales de depositación atmosférica de NO3-N fluctuaron entre 0,53 y 0,57 kg ha-1 año-1 y las de NH4-N fueron entre 6,4 y 2,8 kg ha-1 año-1 para los sitios agrícola-ganaderos de

  10. Hábitos alimentarios de Dosidicus gigas (D' Orbigny, 1835) (Cephalopoda: Teuthoidea) frente a la costa centro-sur de Chile Feeding habits of Dosidicus gigas (D'Orbigny, 1835) (Cephalopoda: Teuthoidea) in the central-south coast off Chile



    Se estudiaron los hábitos alimentarios del calamar rojo Dosidicus gigas (D'Orbigny, 1835) frente a la costa de Chile centro-sur, durante el invierno del año 2005. Se examinaron un total de 52 estómagos, en todos los cuales había contenido alimentario. Los ejemplares provenían de pescas efectuadas por la flota arrastrera industrial que opera entre 36°39' S y 38°55'S sobre la merluza común Merluccius gayi (Guichenot 1848) y a una profundidad media de 290 m sobre la plataforma continental. Para ...

  11. The genetic relationship between mafic dike swarms and plutonic reservoirs in the mesozoic of central chile (30A degrees-33A degrees 45'S) : insights from AMS and geochemistry

    C. Creixell; M.A. Parada; D. Morata; Roperch, Pierrich; Arriagada, C


    Five mafic dike swarms between 30A degrees and 33A degrees 45'S were studied for their geochemical signature and kinematics of magma flow directions by means of AMS data. In the Coastal Range of central Chile (33A degrees-33A degrees 45'S), Middle Jurassic dike swarms (ConcA(3)n and Cartagena dike swarms, CMDS and CrMDS, respectively) and an Early Cretaceous dike swarm (El Tabo Dike Swarm, ETDS) display the presence of dikes of geochemically enriched (high-Ti) and depleted (low-Ti) basaltic c...

  12. Evolución tectónica, paleogeográfica y metalogénica durante el Cenozoico en los Andes de Chile norte y central e implicaciones para las regiones adyacentes de Bolivia y Argentina


    La orogenia incaica dio origen a un importante relieve en el Eoceno Medio, el que se concentró en el ámbito del arco magmático precedente, la Cordillera Incaica. Este relieve positivo de orientación NNE se extendió desde el sur de Perú hasta la región central de Chile y separó dos dominios paleogeográficos que tuvieron evoluciones diferentes durante el resto del Cenozoico. El dominio occidental se caracterizó por el predominio de procesos de erosión y sedimentación. En el dominio oriental tam...

  13. Hydrochemical and isotopic patterns in a calc-alkaline Cu- and Au-rich arid Andean basin: The Elqui River watershed, North Central Chile

    Highlights: ► Major ions are provided by rock weathering and NaCl recycling. ► Aridity and cal-alkaline lithology effects abate acid drainage. ► Factors affecting hydrochemistry in mineral rich zone are addressed. ► Stable isotopes confirm the meteoric origin of groundwaters. ► High sulfate contents are explained by widespread sulfide minerals. - Abstract: The geochemistry of surface water and groundwater from the Elqui River basin, North-Central Chile, was studied in spring 2007 and fall 2008 to obtain a general understanding of the factors and mechanisms controlling the water chemistry of steep rivers located in mineral-rich, arid to semi arid zones. Besides its uniform intermediate igneous lithology, this basin is known for acid drainage and high As contents in the El Indio Au–Cu–As district, in its Andean head. Abundant tailings deposits are present in the middle part of the basin, where agricultural activities are important. According to the results, the chemical and isotopic composition of the Elqui basin surface water and groundwater is related to uniform calc-alkaline lithology and the major polluting system of the chemically reactive, but closed El Indio mining district. The resulting compositional imprints in surface and ground-water are, (a) high SO4 levels, reaching about 1000 mg/L in the Toro River water, directly draining the mining area; (b) a major depletion of Fe and pollutant metals in surface water after the confluence of the Toro and La Laguna rivers; (c) similar chemical composition of surface and ground-waters that differ in H and O isotopic composition, reflecting the effect of differential evaporation processes downstream of the Puclaro dam; and (d) seasonal variations of Fe, Mn, Cu and Zn in surface water. In contrast, the groundwater chemistry exhibits moderate seasonal changes, mainly in HCO3- content. In spite of the acid drainage pollution, water quality is adequate for human consumption and irrigation. This is a

  14. Modelling the hydrological response of debris-free and debris-covered glaciers to present climatic conditions in the semiarid Andes of central Chile

    Ayala, Alvaro; Pellicciotti, Francesca; MacDonell, Shelley; McPhee, James; Vivero, Sebastián; Campos, Cristián; Egli, Pascal


    We investigate the main contributors to runoff of a 62 km2 glacierized catchment in the semiarid Andes of central Chile, where both debris-free and debris-covered glaciers are present, combining an extensive set of field measurements, remote sensing products and an advanced glacio-hydrological model (TOPKAPI-ETH). The catchment contains two debris-free glaciers reaching down to 3900 m asl (Bello and Yeso Glaciers) and one debris-covered avalanche-fed glacier reaching to 3200 m asl (Piramide Glacier). A unique dataset of field measurements collected in the ablation seasons 2013-14 and 2014-15 included four automatic weather stations, manual measurements of snow depth and debris cover thickness, discharge measurements at glaciers outlets, photographic monitoring of surface albedo as well as ablation stakes measurements and snow pits. TOPKAPI-ETH combines physically-oriented parameterizations of snow and ice ablation, gravitational distribution of snow, snow albedo evolution, glacier dynamics, runoff routing and the ablation of debris-covered ice.We obtained the first detailed estimation of mass balance and runoff contribution of debris-covered glaciers in this mountainous region. Results show that while the mass balance of Bello and Yeso Glaciers is mostly controlled by air temperature lapse rates, the mass balance of Piramide Glacier is governed by debris thickness and avalanches. In fact, gravitational distribution by avalanching on wet years plays a key role and modulates the mass balance gradient of all glaciers in the catchment and can turn local mass balance from negative to positive. This is especially the case for Piramide Glacier, which shows large amounts of snow accumulation below the steep walls surrounding its upper area. Despite the thermal insulation effect of the debris cover, the contribution to runoff from debris-free and debris-covered glaciers is similar, mainly due to elevation differences. At the catchment scale, snowmelt represents more than 60

  15. Chile ushers in new hydro era

    The planned construction of two hydroelectric power plants at Peuchen and Mampil, will help to meet Chile's growing electricity demand. Securing finance for the project has been straight forward thanks to the optimal hydrological conditions, rivers with a very strong flow providing a large head of water over short distance. Hydropower plays a central role in Chile's generating capacity providing 70% of total energy consumption. Thus, the future of these projects will be highly successful, it is argued. (UK)

  16. Parasite loads and altitudinal distribution of Liolaemus lizards in the central Chilean Andes Cargas parasitarias y distribución de lagartijas Liolaemus en los Andes de Chile central



    Full Text Available This study compared the distributions of ten species of Liolaemus lizards in the central Chilean Andes to the distributions of four types of parasites: malaria-causing Plasmodium, gut nematodes, ticks, and mites. We wanted to see if parasite numbers might be a factor in determining distributional limits of the lizards. We found that there was no evidence of malarial infestation of the lizards, that ticks were almost absent, that more often than not mite numbers decreased at the distributional limits of the lizards, and that gut nematodes confined to the herbivorous lizards in our sample may well be beneficial rather than detrimental. Rather than parasitism, other biotic interactions (e.g., predation or competition are more likely candidates as factors influencing lizard elevational distributions, as are abiotic characteristics such as microhabitat availabilities and thermal factorsEste estudio compara las distribuciones de diez especies de lagartijas Liolaemus en los Andes de Chile central, con las distribuciones de cuatro tipos de parásitos: Plasmodium causantes de malaria, nemátodos intestinales, garrapatas y ácaros. Quisimos verificar si los números de parásitos pudieran ser un factor determinante de los límites de distribución de las lagartijas. Encontramos que no había evidencia de infestación por malaria en las lagartijas; que las garrapatas estaban casi ausentes; que los números de ácaros más a menudo decrecían que aumentaban en los límites distribucionales de las lagartijas; y que los nemátodos intestinales confinados a las lagartijas herbívoras en nuestra muestra bien podían ser beneficiosos antes que dañinos. Más bien que parasitismo, otras interacciones bióticas (e.g., depredación o competencia son candidatos más probables como factores que influyen las distribuciones altitudinales de las lagartijas, además de características abióticas tales como la disponibilidad de microhábitats y los factores térmicos

  17. La vertebración territorial en regiones de alta especialización: Valle Central de Chile. Alcances para el desarrollo de zonas rezagadas en torno a los recursos naturales



    Full Text Available Los procesos de reestructuración económica y la apertura de los mercados han generado múltiples y variadas consecuencias sobre nuestros territorios. Quizás para Chile, como para otros países latinoamericanos, uno de los más importantes procesos a nivel regional es el desarrollo de espacios altamente especializados o regiones-commodities. Distintos trabajos académicos señalan que interiormente, en conjunto con áreas de gran competitividad, se están generando áreas rezagadas o alejadas de los dinamismos económicos. Por lo tanto: ¿ En qué ha derivado su modelo de vertebración territorial y su sistema de centros poblados ? ¿Cuáles son las características de estas áreas rezagadas ? Y por ende, ¿cuáles son los desafíos a los cuales se enfrentan? El Valle Central de Chile es una de estas áreas donde se evidencia dicha especialización. Por tanto, analizaremos la estructura física territorial en las que han derivado estas regiones y el papel que cumplen sus centros poblados en los nuevos escenarios. A partir de la caracterización de su vertebración territorial avanzaremos hacia la definición de sus zonas menos favorecidas, e intentaremos generar algunas hipótesis que respondan a sus desafíos y requerimientos futuros.Economic restructuring processes and market opening have generated multiple and varied consequences in our territories. Perhaps for Chile, as with other Latin American countries, one of the most important processes at the regional level is the development of highly specialized spaces or commodity-regions. Different academic work indicates that within these spaces, as well as areas of high competitiveness, there are also backward areas with limited economic dynamism. Consequently: What has happened to the model of a territorial spine and system of population center? What are the characteristics of these backward areas? In addition, what are the challenges to be faced? Chile's Central Valley is one of the areas


    Barbara Theilen-Willige; Felipe Barrios Burnett


    The potential contribution of remote sensing and GIS techniques to earthquake hazard analysis was investigated in Valparaiso in Chile in order to improve the systematic, standardized inventory of those areas that are more susceptible to earthquake ground motions or to earthquake related secondary effects such as landslides, liquefaction, soil amplifications, compaction or even tsunami-waves. Geophysical, topographical, geological data and satellite images were collected, processed, and integr...

  19. Estimación de la biomasa de langostino amarillo (Cervimunida johni, aplicando Modelo Lineal Generalizado a registros de captura por área barridaen la zona central de Chile Estimating yellow squat lobster (Cervimunida johni biomass by applying a generalized linear model to catch records per swept area in central Chile

    Cristian Canales


    Full Text Available La información obtenida en cruceros de evaluación directa de langostino amarillo (Cervimunida johní realizados en la zona central del Chile (32°-38°S entre 1997 y 2009, permitió modelar los cambios en la densidad anual de este recurso mediante Modelo Lineal Generalizado (MLG. El objetivo de este enfoque fue tanto minimizar el efecto de los distintos criterios y diseños de muestreo que han sido empleados en el tiempo, como también determinar los efectos que explican las variaciones en la densidad de este recurso. Lo anterior permitió estimar el valor esperado de la densidad anual para el cálculo de biomasa mediante el método de "área barrida". Los registros lance a lance de captura por unidad de área barrida (CPUA permitieron la identificación y medición de los focos de abundancia, además de caracterizar la distribución y área que ha ocupado el recurso en el tiempo. El MLG identificó como efectos significativos el año, la zona, la profundidad, y las interacciones anuales de primer orden, explicando con ello el 43% de la devianza residual del modelo. Los principales efectos que explican las variaciones de la CPUA son el año y la interacción año-zona. Se determinó que la zona con mayor abundancia promedio corresponde a la delimitada entre 32° y 34°S, de igual manera que en el rango de profundidad menor a 250 m. Dentro del período analizado, se determinó que la población de este recurso incrementó en biomasa de manera sostenida hasta el 2006, principalmente en la zona norte del área de estudio, seguida de una fuerte reducción que al 2009 equivale al 75% respecto del máximo, reflejada en una biomasa de 11.000 ton.Changes in the annual density of the yellow squat lobster (Cervimunida johni were modeled using a generalized linear model (GLM, using information obtained during direct stock assessment cruises carried out in central Chile (32°-38°S between 1997 and 2009. The purpose of this approach was to minimize the

  20. Botanical Composition of Alpaca (Lama pacos Linn. Diet in a Central Mediterranean Range of Chile Composición Botánica de la Dieta de Alpaca (Lama pacos Linn. en un Pastizal del Secano Mediterráneo de la Zona Central de Chile

    G Castellaro


    Full Text Available The re-introduction of domestic South American camelids (alpacas and llamas in the central zone of Chile makes it necessary to study their behaviour and adaptability. Since it is fundamental to characterize the camelid’s diet, the present work had as an objective the determination of the plant species selected by the alpacas (Lama pacos Linn. in different phenological stages (vegetative, reproductive and dry season. The study was carried out over three years in a paddock of 2.5 ha of sparse shrubland dominated by Acacia caven (Mol. Mol. and annual species in the herbaceous stratum, which were continually grazed by five male alpacas. The botanical composition and the forage dry matter available for grazing in the pasture was evaluated. Botanical composition of diets was estimated with the microhistological technique, using dung samples collected directly from the rectum. During the vegetative season, the most consumed plant species were annual and perennial grasses. In the reproductive season, the most important components of the diet were woody plant species, annual grasses and forbs. In the dry season, the diet was composed of a high percentage of woody plant species.La reintroducción de camélidos sudamericanos domésticos (alpaca y llamas en la zona central de Chile, hace necesario estudiar su comportamiento y adaptabilidad. En este contexto, la caracterización de la dieta es fundamental. Por ello, el presente trabajo tuvo como objetivo determinar las especies vegetales seleccionadas por las alpacas en diferentes etapas fenológicas del pastizal (vegetativo, reproductivo y seco. El estudio se realizó durante tres temporadas en un potrero de 2,5 ha ocupado por un matorral claro dominado por Acacia caven (Mol. Mol. y especies anuales en el estrato herbáceo, las cuales fueron pastoreadas continuamente por cinco alpacas macho. En la pradera se evaluó la composición botánica y la disponibilidad de la materia seca bajo pastoreo. La

  1. Efectos de la planta en cojín Oreopolus glacialis (Rubiaceae sobre la riqueza y diversidad de especies en una comunidad alto-andina de Chile central Effects of the cushion plant Oreopolus glacialis (Rubiaceae on species richness and diversity in a high-Andean plant community of central Chile



    Full Text Available Las plantas en cojín que crecen en ambientes de alta montaña modifican microclimáticamente su entorno, generando microhábitats favorables para el establecimiento de otras especies, actuando como nodrizas. Varios estudios han demostrado que los cojines contienen una mayor riqueza de especies que los espacios abiertos. Sin embargo, hasta ahora, no se ha evaluado el efecto de los cojines sobre otros parámetros comunitarios como la abundancia de individuos, la diversidad y la equitatividad. En este trabajo se analiza el efecto que posee Oreopolus glacialis, una planta en cojín de la cordillera andina, sobre la riqueza, abundancia, diversidad y equitatividad de la comunidad vegetal en un ambiente de alta montaña ubicado a 1.900 m en Chile central. Se determino la riqueza y abundancia de especies que crecen tanto sobre cojines de O. glacialis como en los espacios abiertos entre cojines. Los resultados mostraron que la riqueza de especies y la abundancia de individuos por unidad de área es mayor dentro de los cojines que fuera de ellos. Sin embargo, los valores de diversidad y equitatividad sobre O. glacialis fueron menores que fuera de ellos debido a la presencia de algunas especies dominantes. Análisis particulares de la frecuencia y abundancia de cada especie mostraron que no todas las especies son afectadas de la misma manera por la presencia de este cojín, por lo que O. glacialis actuaría como nodriza sólo para una parte limitada de los componentes de la comunidadCushion plants growing in high mountain habitats can modify the microclimate within their canopy generating microhabitats more favorable for the recruitment of other plant species, acting as nurse plants. Although several studies have shown that species richness is higher within cushions than outside them, no attempts have been made in order to assess the effect of cushions on other community aspects such as total and individual abundance, diversity and evenness. In this study

  2. Shoreline changes in Concón and Algarrobo bays, central Chile, using an adjustment model Cambios en la línea litoral de las bahías de Algarrobo y Concón, Chile central, a través de un modelo de ajuste

    Carolina Martinez


    Full Text Available Adjustment models for both Algarrobo and Concón bays, central Chile, are presented herein; the results show a nearly logarithmic spiral shape for the shore. Spatial-temporal variations in the shorelines of both bays were found based on aerial photographs from different years. The results indicate important variations in the relative position of the Concón Bay shoreline between 1945 and 2006, with extreme oscillations (-368 to 123.8 m only occurring in the proximal zone, where the Aconcagua Estuary is located. On the other hand, the spatial-temporal variations in the Algarrobo Bay shoreline between 1967 and 2006 are moderate (131 in the proximal and -73 in the distal zone. Whereas Concón Bay exhibits a stable state of equilibrium for the past 60 years, if the estuary zone is excluded, Algarrobo Bay presents a stable state with a tendency for growth in the proximal zone and retreat in the distal zone. The results are discussed in terms of coastal changes associated with highly urbanized shorelines and applications for coastal area management that are derived from the modelsSe presentan los resultados de la aplicación de un modelo de ajuste para las bahías de Algarrobo y Concón en Chile central, cuya forma se aproxima a una espiral logarítmica. A partir del uso de fotografías aéreas correspondientes a diferentes años, se determinaron las variaciones espacio-temporales de la línea litoral en ambas bahías. Los resultados indican que la bahía de Concón ha presentado importantes variaciones en la posición relativa de su línea litoral para el período 1945 a 2006, únicamente en su zona proximal, lugar en donde se localiza el estuario Aconcagua con oscilaciones extremas entre -368 m y 123,8 m. En la bahía de Algarrobo, las variaciones espacio-temporales de la línea litoral son de magnitud moderada para el período comprendido entre 1967 y 2006, presentando valores extremos de 131 m en la zona proximal y de -73 m en la zona distal

  3. Floristic changes in alpine plant communities induced by the cushion plant Azorella madreporica (Apiaceae in the Andes of central Chile Cambios florísticos en comunidades de plantas alpinas inducidos por la planta en cojín Azorella madrepórica (Apiaceae en los Andes de Chile central



    Full Text Available It is well known that the number of plant species associated with nurse plants increases with elevation. However, studies conducted so far have largely ignored the effect of nurse plants on other community attributes, such as the species abundances, diversity and evenness. Moreover, changes in these community attributes along environmental gradients have also been seldom examined. The present study evaluates the effect of the cushion plant Azorella madrepórica (Apiaceae on species richness, species abundance, diversity and evenness of vascular plants at two elevations in the Andes of central Chile. Theoretically, the impact of this nurse cushion plant on these community attributes should be grater at a higher elevation. Results showed that the proportion of plant species associated with cushion plants increases with elevation, and the abundance of some species is also greater within cushions than on bare ground. Although the proportion of species growing within cushions increased with elevation, diversity and evenness were higher on bare ground. This is due to some few species that attained very high densities within cushions, generating assemblages highly dominated by some few species. Ordination analyses indicated differences in species assemblages within and outside A. madrepórica at the higher elevation. Therefore, the influence of cushion plants on community structure changes with elevation. Accordingly, we suggest that attributes other than species richness must be included in future studies in order to analyze the impact of nurse species on community structure along environmental gradients.Se sabe que el número de especies asociado a plantas nodrizas aumenta con la altitud. Sin embargo, el efecto de plantas nodrizas sobre otros atributos de las comunidades, como la abundancia de especies, diversidad y equidad, ha sido largamente ignorado. Más aún, cambios en estos atributos en gradientes ambientales han sido pocas veces examinados

  4. The Donoso copper-rich, tourmaline-bearing breccia pipe in central Chile: petrologic, fluid inclusion and stable isotope evidence for an origin from magmatic fluids

    Skewes, M. Alexandra; Holmgren, Carmen; Stern, Charles R.


    The copper-rich, tourmaline-bearing Donoso breccia pipe is one among more than 15 different mineralized breccias in the giant (>50 million metric tonnes of copper) Miocene and Pliocene Río Blanco-Los Bronces copper deposit in the high Andes of central Chile. This breccia pipe, bracketed in age between 5.2 and 4.9 Ma, has dimensions of 500 by 700 m at the current surface 3,670 m above sea level. Its roots have yet to be encountered, and it is >300 m in diameter at the depth of the deepest drill holes. The Donoso breccia is, for the most part, monolithic, containing clasts of the equigranular quartz monzonite pluton which hosts the pipe. It is matrix supported, with between 5 and 25% of the total rock volume consisting of breccia-matrix minerals, which include tourmaline, quartz, chalcopyrite, pyrite, specularite, and lesser amounts of bornite and anhydrite. An open pit mine, centered on this breccia pipe, has a current production of 50,000 tonnes of ore per day at an average grade of 1.2% copper, and copper grade in the breccia matrix is significantly higher. Measured δ18O for tourmaline and quartz from the matrix of the Donoso breccia at different levels of the pipe range from +6.9 to +12.0‰, and measured δD in tourmaline ranges from -73 to -95‰. Temperatures of crystallization of these minerals, as determined by the highest homogenization temperatures of highly saline fluid inclusions, range from 400 to >690°C. When corrected for these temperatures, the stable isotope data indicate that fluids from which these breccia-matrix minerals precipitated were magmatic, with δ18O between +5.6 to +9.1‰ and δD between -51 to -80‰. These isotopic data preclude participation of a significant amount of meteoric water in the formation of the Donoso breccia. They support a model in which brecciation is caused by expansion of magmatic fluids exsolved from a cooling pluton, and breccia-matrix minerals, including copper sulfides, precipitated from the same magmatic

  5. Consistent magmatic and magnetic anisotropy data in La Gloria Pluton, central Chile: Implications for the magma flow record in a shallow pluton

    Payacan, I.; Gutierrez, F. J.; Bachmann, O.; Parada, M.


    The magmatic origin of the anisotropy of magnetic susceptibility (AMS) is examined in comparison with magmatic anisotropy data in a small, shallow, silicic magma reservoir in the upper crust. La Gloria Pluton (LGP) is a 10 Ma granodiorite/quartz monzonite of about 250 km3 located in the southern Andes, central Chile. LGP represents a particularly simple case of a silicic intrusion which was assembled in a few pulses and cooled over a short time interval. Hornblende, biotite and minor magnetite are ubiquitous mafic phases. The AMS tensor indicates that magnetic fabric has an oblate shape (i.e. magnetic foliation is higher than magnetic lineation). Lineations are weak (values up to 1.05), have a N-NW trend with a nearly horizontal dip and represent axisymmetric convection parallel to the main pluton elongation. Foliations are more pronounced (values up to 1.14), having NW trends and dips that vary gradually from vertical at the walls, to horizontal at the center and near the roof of the chamber. We interpret this to represent shear localization near the magma locking point along solidification fronts. Magmatic anisotropy data were obtained by measuring mineral length, width and orientation in the three main planes of the AMS tensor. We define the planes Pmax, Pint, and Pmin as orthogonal to the maximum, intermediate, and minimum axes of the AMS tensor, respectively. Mineral data were collected for plagioclase and amphibole + bitotite independently. For each site, the Bingham distribution with 95% of confidence is used to determine the mean mineral orientation and their angle difference with the AMS axes. Preliminary results indicate that mean crystal orientations are well defined for Pmax and Pint for all analyzed minerals, but Pmin is only well constrained for amphibole + bitotite and poorly constrained for plagioclase. Angle differences generally decrease with magnetic anisotropy but are independent of the size and aspect ratio of the crystals. Mean values of

  6. Using 137Cs and 210Pbex and other sediment source fingerprints to document suspended sediment sources in small forested catchments in south-central Chile

    A study of the impact of forest harvesting operations on sediment mobilization from forested catchments has been undertaken in south-central Chile. The study focused on two sets of small paired catchments (treatment and control), with similar soil type, but contrasting mean annual rainfall, located about 400 km apart at Nacimiento (1200 mm yr−1) and Los Ulmos (2500 mm yr−1). The objective was to study the changes in the relative contribution of the primary sources of fine sediment caused by forestry operations. Attention focused on the pre-harvest and post-harvest periods and the post-replanting period was included for the Nacimiento treatment catchment. The sediment source fingerprinting technique was used to document the contributions of the potential sources. Emphasis was placed on discriminating between the forest slopes, forest roads and channel erosion as potential sources of fine sediment and on assessing the relative contributions of these three sources to the sediment yield from the catchments. The fallout radionuclides (FRNs) 137Cs and excess lead-210, the environmental radionuclides 226Ra and 40K and soil organic matter (SOM) were tested as possible fingerprints for discriminating between potential sediment sources. The Kruskal–Wallis test and discriminant function analysis were used to guide the selection of the optimum fingerprint set for each catchment and observation period. Either one or both of the FRNs were selected for inclusion in the optimum fingerprint for all datasets. The relative contribution of each sediment source to the target sediment load was estimated using the selected fingerprint properties, and a mixing model coupled with a Monte Carlo simulation technique that takes account of uncertainty in characterizing sediment source properties. The goodness of fit of the mixing model was tested by comparing the measured and simulated fingerprint properties for the target sediment samples. In the Nacimiento treatment catchment the

  7. Relaciones entre la distribución de recursos pelágicos pequeños y la temperatura superficial del mar registrada con satélites NOAA en la zona central de Chile Relationships between the small pelagic resources distribution and the sea surface temperatures recorded by NOAA satellites from Chile central zone

    Eleuterio Yáñez R


    Full Text Available Se realiza un estudio exploratorio para determinar la posibilidad de introducir el uso de imágenes de temperatura superficial del mar (TSM, confeccionadas con datos de satélites NOAA, en las pesquerías de recursos pelágicos pequeños de la zona central de Chile. Se determinan significativas relaciones entre los rendimientos de las especies analizadas y los gradientes térmicos (GRT en forma particular. Estos se asocian a aguas oceánicas en el caso del jurel (Trachurus murphyi, y a surgencias costeras en relación con la anchoveta (Engraulis ringens y sardina común (Clupea bentincki. Se concluye que el uso de imágenes de TSM-NOAA puede jugar un papel importante en la operación de flotas, particularmente de las del tipo de embarcaciones consideradas en el presente trabajo.A survey study was conducted to assess the possibility of introducing the use of sea surface temperatures (SST, obtained from NOAA satellite data, for the small pelagic fisheries resources. Relationships between species yields and thermal gradients (TGR were found significant. Jack mackerel (Trachurus murphyi yields were largely related with a strong thermal gradient next to oceanic waters, while anchovy (Engraulis ringens and common sardine (Clupea bentincki yields were mainly associated to the development of coastal upwelling events. It is concluded that the use of SST-NOAA images can play an important role in fleet operations, particularly in the case ot the type of boats considered in this paper.

  8. Nurse effect in seedling establishment: facilitation and tolerance to damage in the Andes of central Chile Efecto nodriza en el establecimiento de plántulas: facilitación y tolerancia al daño en los Andes de Chile central



    Full Text Available Nurse effects, which occur when one plant species enhances the survival or growth of another plant species, are predicted to be most relevant in stressful environments. These effects are particulary important during seedling establishment due to their vulnerability to both biotic and abiotic factors, such as herbivory and drought. Tolerance to herbivory reflects the degree to which plants are able to regrow and reproduce after damage, and should vary with resource availability. In the high Andes of central Chile, the cushion plant Laretia acaulis (Apiaceae acts as a buffer against environmental stress, enhancing survival of several associated plant species. We hypothesized that tolerance to herbivory of seedlings growing inside the canopy of L. acaulis should be greater than that of seedlings growing outside the cushion plant. We conducted a field experiment to test this hypothesis for two native perennial species in the high Andes of central Chile: Hordeum comosum (Poaceae and Haplopappus anthylloides (Asteraceae. Seedlings of each species were planted inside and outside L. acaulis cushions and half of them received manual damage (50 % foliar tissue removed. Seedlings growing inside the nurse species showed high survival independent of the damage treatment. Whereas position (inside or outside the cushion plant did not affect tolerance of Haplopappus anthylloides, it significantly affected tolerance of Hordeum comosum. Thus, we found similar survival of damaged and control seedlings of H. comosum inside the cushions, but survival of damaged seedlings in the bare ground was lower than that of control seedlings. We verified the occurrence of nurse effects of Laretia acaulis on the establishment of both species, and detected enhancement of tolerance to damage in Hordeum comosum in this stressful habitatSe ha sugerido que el efecto nodriza, el cual se evidencia cuando una especie vegetal incrementa la supervivencia o el crecimiento de otra, es m

  9. Mortalidad natural de larvas de merluza común (Merluccius gayi gayi frente a Chile centro-sur en relación a su distribución espacial y grado de agregación Natural mortality of chilean hake (Merluccius gayi gayi larvae of central-south Chile in relation to their spatial distribution and patchiness

    Cristian Vargas


    Full Text Available Existe escasa información sobre la ecología y sobrevivencia de estados larvales de merluza común frente a las costas de la VIII Región, Chile. Debido a que la agregación puede ser un factor determinante en la depredación de larvas de peces, en el presente trabajo se estudia su influencia en la mortalidad natural instantánea de larvas de merluza común (Merluccius gayi gayi Guichenot, 1848, estimada a través del modelo mortalidad-agregación de McGurk (1986. Las muestras (red bongo 500µ fueron obtenidas durante un crucero efectuado en la zona costera del centro-sur de Chile (36º22'S _ 37º10'S durante septiembre de 1991. La tasa de mortalidad natural instantánea fluctuó entre 0,1 y 0,38 d-1 para larvas en un rango de tallas de 4 a 11 mm de longitud estándar. Los valores de mortalidad obtenidos a través del modelo de interacción mortalidad-agregación (McGurk, 1986, revelaron que la distribución espacial (agregación podría influenciar considerablemente a la mortalidad, especialmente en larvas de mayor longitud (> 9 mm.At the present time limited information is available about ecology and survival of Chilean hake larvae off coast from VIII Region, Chile. Because spatial patchiness of larvae may be an important factor on the predation of fish larvae, its influence on the instantaneous natural mortality of larval Chilean hake (Merluccius gayi gayi Guichenot, 1848 was studied using the mortality-patchiness model (McGurk, 1986. Samples (bongo net 500µ were taken during a survey carried out in the coastal zone off Central-South Chile (36º22'S _ 37º10'S during september 1991. The natural mortality for larvae between 4 to 11 mm of standard length fluctuated between 0,1 and 0,38 d-1. The mortality values obtained using the mortality-patchiness model (McGurk, 1986, showed that the spatial distribution (patchiness would influence the larval mortality, specially in the largest ones (> 9 mm.

  10. Abanico East Formation: petrology and geochemistry of volcanic rocks behind the Cenozoic arc front in the Andean Cordillera, central Chile (33°50'S

    Marcia Muñoz


    Full Text Available The stratigraphy, chemistry and age of rocks assigned to the eastern portion of the Abanico Formation exposed along the El Volcán river valley, Principal Cordillera east of Santiago (30º50'S/70º12'-70º5'W, are reported and discussed. This ca. 3,300 m thick succession is mainly composed of basalts, basaltic andesites and volcaniclastic rocks. 40Ar/39Ar radiometric dates on plagioclase from the lava flows yield Oligocene-lower Miocene ages with a maximum age of 34.3 ±0.4 Ma for the lower part and a plateau age of 21.4±1.0 Ma for the upper part of the succession. The lava flows show calc-alkaline affinities and have chemical characteristics that are typical of arc volcanic rocks erupted in an active continental margin. A temporal chemical evolution in the sequence is indicated by upward increases in concentrations of LILE and LREE elements and LaN/YbN ratios. This pattern can be attributed to increasing contributions of fluids derived from the subducted lithosphere with time. A chemical comparison of these rocks with Oligocene-lower Miocene volcanic rocks from the Cerro Abanico and Chacabuco areas on the western border of the Principal Cordillera, east of Santiago, and at the northern end of the Central Depression reveals west to east compositional variations. From west to east these variations include: (1 increasing LILE and LREE concentrations, LaN/YbN ratios and Sr and Nd initial isotopic ratios, and (2 decreasing LILE/HFSE and LREE/HFSE ratios. These pattern can be attributed to a west to east decrease in the contribution of slab derived fluids and increase in the influence of crustal contamination processesLa formación Abanico Este: petrología y geoquímica de las rocas volcánicas detrás del arco Cenozoico en la Cordillera Andina, Chile central (33º50'S. Se presentan los resultados del estudio de la estratigrafía, química y edades de rocas asignadas a la franja oriental de la Formación Abanico expuestas en la ladera sur del R

  11. Low prevalence of Factor V Leiden and the prothrombin G20210A mutation in a healthy population from the central-south region of Chile Baixa prevalência do Fator V Leiden e da mutação da protrombina G20210A em uma população sã da região centro-sul do Chile

    Iván Palomo; Fabian Segovia; Daniela Parra; Marcelo Alarcón; Edgardo Rojas


    Thrombosis is a result of the interaction between predisposing genetic polymorphisms and acquired risk factors. The two prothrombotic polymorphisms which are most frequently associated with thrombosis are factor V (FV) Leiden and the prothrombin (PT) G20210A mutation. The objective of this work was to investigate the prevalence of both factors in the central-south region of Chile. Determination of the frequency was carried out by means of a genetic analysis of 1200 healthy, non-native individ...

  12. Nuevo esquema estratigráfico para los depósitos marinos mio-pliocenos del área de Navidad (33º00'-34º30'S, Chile central New stratigrafic scheme for the Mio-Pliocene marine deposits of the Navidad area (33º00'-34º30'S, central Chile

    Alfonso Encinas


    Full Text Available Varios autores han propuesto diferentes esquemas estratigráficos para los depósitos sedimentarios neógenos marinos que afloran en la zona costera de Chile central entre Valparaíso (~33°00'S y Punta Topocalma (~34°30'S, sin que exista un consenso al respecto. Tampoco existe acuerdo respecto a las correlaciones entre los depósitos que afloran en la parte norte de dicha zona, entre Valparaíso y San Antonio (~33°30'S con aquellos que aparecen en la parte sur, entre San Antonio y Punta Topocalma. Sobre la base de nuevos estudios estratigráficos, sedimentológicos y paleontológicos se propone, de manera formal, un nuevo esquema estratigráfico para estos depósitos. De acuerdo con este nuevo esquema se definen la Formación Navidad (Mioceno Superior-Plioceno Inferior y las formaciones Licancheu, Rapel y La Cueva (Plioceno. Se propone la elevación de las tres primeras unidades (Navidad, Licancheu y Rapel, generalmente consideradas como miembros en clasificaciones anteriores, al rango de formaciones debido a que se encuentran separadas por discontinuidades (paraconformidades de escala regional. En el presente trabajo se definen estas unidades, se revisan los esquemas anteriores y se justifica la proposición de este nuevo esquemaDifferent stratigraphic schemes have been proposed by various authors for the Neogene marine sedimentary deposits cropping out along the central Chilean coast between Valparaíso (~33°00'S and Punta Topocalma (~34°30'S, without any consensus having been reached. Neither does any agreement exist with respect to the correlation between the deposits cropping out in the northern part of this area, between San Antonio (~33°30'S and Valparaíso, and those of the southern part, between San Antonio and Punta Topocalma. Based on new stratigraphic, sedimentologic and paleontologic studies we propose a formal, new stratigraphic classification for this area. According to this scheme we define the Navidad Formation (Upper

  13. Liolaemus carlosgarini and Liolaemus riodamas (Squamata: Liolaemidae), two new species of lizards lacking precloacal pores, from Andean areas of central Chile.

    Esquerré, Damien; Núñez, Herman; Scolaro, José Alejandro


    Most of the lizards of the Liolaemus genus present precloacal pores in males, with few exceptions in species of the lineomaculatus and neuquensis groups, and in the elongatus-kriegi complex. The elongatus-kriegi complex, belonging to the Liolaemus (sensu stricto) subgenus, is composed of medium sized, saxicolous, viviparous and insectivorous or omnivorous lizards, distributed between the Andean and Patagonian zones of Chile and Argentina. We reviewed the taxonomic history of this group, and we describe two new species, Liolaemus carlosgarini, found in the vicinity of the Maule Lagoon, in the Maule Region, Chile, and Liolaemus riodamas, described from the population that was originally designated as Liolaemus cf ceii, from Las Damas River, near the Termas del Flaco locality, in the Libertador Bernardo O'Higgins Region, thereby based on this research L. ceii is eliminated from the species belonging to Chile. Both species have as a diagnostic character the absence of precloacal pores, and we suggest here their presumptive systematic relationships in Liolaemus. We analyzed ten species of Liolaemus, in order to perform a phylogenetic analysis based on external morphology, using mostly squamation and morphometric characters. The analysis was performed using PAUP, with the Maximum Parsimony criterion. In addition, through diaphanisation, we studied and described the osteology of the new species. We conclude that species lacking precloacal pores do not form a monophyletic group, and that constructing a phylogeny using only external morphology, at least for this group of reptiles, is insufficient to establish solid phyletic relationships. Other sort of characters should complement the morphological ones. PMID:26131484

  14. Borage (Borago officinalis L. Response to N, P, K, and S Fertilization in South Central Chile Respuesta de Borraja (Borago officinalis L. a la Fertilización con N, P, K, y S en el Centro Sur de Chile

    Marisol T. Berti


    Full Text Available Borage (Borago officinalis L. is an oilseed with a high gamma-linolenic acid (GLA content in its seed. The objective of this study was to determine the response of borage seed yield, oil content, and fatty acid composition to N, P, K, and S fertilizer treatments. Three experiments were conducted in Osorno (40º22’ S, 73º04’ W; 72 m.a.s.l., Chile. The first experiment was conducted during the 2005-2006 growing season, with four N rates (0, 100, 200, and 300 kg N ha-1, three P rates (0, 60, and 120 kg P2O5 ha-1 and two K rates (0 and 150 kg K2O ha-1. The second experiment was conducted in 2006-2007 and evaluated only the effect of four N rates (0, 50, 100 and 150 kg N ha-1 was evaluated because there was no response to P and K in the first experiment. The third experiment was conducted in the 2005-2006 and 2006-2007 and evaluated only two rates of S, 0 and 40 kg S ha-1. Seed yield was not affected by N, P, K, or their interactions in any of the experiments. As N rates increased GLA content increased. Mean seed yield increased to 98 kg ha-1 when applying 40 kg S ha-1. Results indicate that borage has a higher response to S applications than N. Further research is needed to determine the interactions between N and S applications, given that the experiments were conducted on soils with high P and K levels.La borraja (Borago officinalis L. es una oleaginosa con alto contenido de ácido gamma-linolénico (GLA en su semilla. El objetivo de este estudio fue determinar la respuesta en rendimiento de semillas, contenido y composición del aceite de borraja, a la fertilización con N, P, K y S. Tres experimentos fueron conducidos en Osorno (40º22’ S, 73º04’ O; 72 m.s.n.m., Chile. El primer experimento fue conducido en la temporada 2005-2006, con cuatro dosis de N (0, 100, 200 y 300 kg N ha-1, tres dosis de P (0, 60 y 120 kg P2O5 ha-1 y dos dosis de K (0 y 150 kg K2O ha-1. El segundo experimento fue conducido en el 2006-2007, cuando sólo se


    Barbara Theilen-Willige


    Full Text Available The potential contribution of remote sensing and GIS techniques to earthquake hazard analysis was investigated in Valparaiso in Chile in order to improve the systematic, standardized inventory of those areas that are more susceptible to earthquake ground motions or to earthquake related secondary effects such as landslides, liquefaction, soil amplifications, compaction or even tsunami-waves. Geophysical, topographical, geological data and satellite images were collected, processed, and integrated into a spatial database using Geoinformation Systems (GIS and image processing techniques. The GIS integrated evaluation of satellite imageries, of digital topographic data and of various open-source geodata can contribute to the acquisition of those specific tectonic, geomorphologic/ topographic settings influencing local site conditions in Valparaiso, Chile. Using the weighted overlay techniques in GIS, susceptibility maps were produced indicating areas, where causal factors influencing near- surface earthquake shock occur aggregated. Causal factors (such as unconsolidated sedimentary layers within a basin’s topography, higher groundwater tables, etc. summarizing and interfering each other, rise the susceptibility of soil amplification and of earthquake related secondary effects. This approach was used as well to create a tsunami flooding susceptibility map. LANDSAT Thermal Band 6-imageries were analysed to get information of surface water currents in this area.

  16. Importance of water quality on plant abundance and diversity in high-alpine meadows of the Yerba Loca Natural Sanctuary at the Andes of north-central Chile Importancia de la calidad del agua sobre la abundancia y diversidad vegetal en vegas altoandinas del Santuario Natural Yerba Loca en los Andes de Chile centro-norte



    Full Text Available Porphyry Cu-Mo deposits have influenced surface water quality in high-Andes of north-central Chile since the Miocene. Water anomalies may reduce species abundance and diversity in alpine meadows as acidic and metal-rich waters are highly toxic to plants The study assessed the importance of surface water quality on plant abundance and diversity in high-alpine meadows at the Yerba Loca Natural Santuary (YLNS, central Chile (33°15' S, 70°18' W. Hydrochemical and plant prospecting were carried out on Piedra Carvajal, Chorrillos del Plomo and La Lata meadows the growing seasons of 2006 and 2007. Direct gradient analysis was performed through canonical correspondence analysis (CCA to look for relationships among water chemistry and plant factors. High variability in water chemistry was found inside and among meadows, particularly for pH, sulphate, electric conductivity, hardness, and total dissolved Cu, Zn, Cd, Pb and Fe. Data on species abundance and water chemical factors suggests that pH and total dissolved Cu are very important factor determining changes in plant abundance and diversity in study meadows. For instance, Festuca purpurascens, Colobanthus quitensis, and Arenaria rivularis are abundant in habitals with Cu-rich waters while Festuca magellanica, Patosia clandestina, Plantago barbata, Werneria pygmea, and Erigeron andícola are abundant in habitals with dilute waters.Los megadepósitos de pórfidos de Cu-Mo han influido sobre la calidad de las aguas superficiales en las zonas altoandinas del centro-norte de Chile desde el Mioceno. Estas alteraciones en la calidad de las aguas podrían afectar negativamente a la vegetación presente en las vegas altoandinas, ya que las aguas acidas y ricas en metales son altamente tóxicas para las plantas. En este estudio se evaluó el efecto de la calidad de las aguas en la abundancia y diversidad florística de las vegas altoandinas del Santuario de la Naturaleza Yerba Loca (SNYL, en Chile central (33

  17. Combining point and distributed snowpack data with landscape-based discretization for hydrologic modeling of the snow-dominated Maipo River Basin, in the semi-arid Andes central Chile

    Videla Giering, Y. A., III; McPhee, J. P.


    Snow hydrology in mountain environments plays an important role in the availability of hydrological resources in warm climate areas and height effects, since the magnitude of snowpack, its spatial and temporal distribution is very important to determine the availability of water in the snowmelt season and take forward different productive activities This investigation models and assess the main phenomena hydrological cycle of snow using the software Cold Region Hydrological Model (Pomeroy et al., 2007). The software is a physically based model developed by the centre for hydrology, University of Saskatchewan. The aim of this model is to have a better understanding of hydrological processes involved in cold environments, which are particular in the sense that a host of specific phenomena such as snow and ice accumulation, transport and melt, infiltration through frozen soils, and the like, control the hydrograph timing) The analysis involved the development of a hydrologic model for the Upper Maipo River Basin, with elevations between 800 and 6500 meters above sea level and 5000-km^2 watershed in the Andes of Central Chile which supplies water resources to the capital city of Santiago (7 million inhabitants), to a thriving agricultural region, as well as to hydropower and large mining activities. The paper concludes that there is a differential distribution of snow cover in the study area, determined mainly by steep terrain geomorphology. These factors have been considered in the parameterization of the model, showing considerable variation in storage time, redistributions by blowing snow, melting intervals, infiltration rates and drainage basin. The fictional scenarios modeled demonstrate noticeable changes in the hydrograph, showing the fragile climate and hydrological condition of this basin of Central Chile.

  18. Patrones reproductivos del lobo marino común, Otaria flavescens (Shaw 1800, en el centro-sur de Chile Breeding patterns in southern sea lions, Otaria flavescens (Shaw 1800, in south-central Chile



    Full Text Available El desfase latitudinal de los eventos reproductivos en Otaria flavescens sugiere la existencia de una adaptación fisiológica y conductual a condiciones ambientales locales. La identificación de cambios en los patrones conductuales intraespecíficos frente a modificaciones ambientales sugieren una relación entre estos. Se pretende revisar los patrones reproductivos del O. flavescens, determinando la existencia de una sincronización y estabilidad en ellos durante las temporadas 1996-1997 y 1997-1998 en la colonia de Punta Lobería, Chile. Se realizaron observaciones directas de las agrupaciones y conductas reproductivas empleando binoculares, y apoyadas por el uso de material fílmico y fotográfico. Los resultados evidenciaron modificaciones en, (a el número de harenes (de 28 disminuye a 19, (b la distribución espacial de los harenes (70 % de los harenes durante 1997-1998 se establecieron en el lado norte de la playa reproductiva, durante la temporada anterior estos se distribuyeron a lo largo de toda la playa, (c proporción etaria (un macho: 12 hembras: un juvenil: siete cachorros, desciende a un macho: nueve hembras: dos juveniles: seis cachorros, (d índice de poliginia (de 12,4 a 7,8 HPMT y de 11 a 9 HP, y (e la población organizada en harenes (disminución del 10,3 %. Estas variaciones estarían relacionadas con la reducción del espacio óptimo para el establecimiento de harenes debido a la incorporación de suelo/roca posterior a un derrumbe invernal. Los patrones conductuales reproductivos que se mantuvieron invariables durante las temporadas fueron, (a la estacionalidad de los harenes (constitución durante la cuarta semana de diciembre y disolución en la cuarta semana de febrero, (b el período de partos (inicio durante la segunda semana de enero, finalización durante la cuarta semana de enero, y (c el período de cópulas (inicio durante la tercera semana de enero, finalización durante la segunda semana de febrero. Por lo

  19. Revisiting chlorophyll data along the coast in north-central Chile, considering multiscale environmental variability Reinterpretando datos de clorofila en la costa centro-norte de Chile, considerando variabilidad ambiental de multiescala



    Full Text Available Phytoplankton abundance in the surface mixed layer of the coastal ocean responds to environmental changes at various time scales. Here the "warm", "cold" and "neutral" phases of "three environmental cycles" have been jointly considered to assess chlorophyll-a (Chl-a biomass variability for both the active and relaxed phases of the local, wind-driven coastal upwelling: (i the interannual ENSO cycle (ii the annual (seasonal cycle and (iii the intraseasonal cycle associated with equatorially-sourced, ocean trapped-waves along the coast in northern Chile. The main goal of this study is to quantitatively assess the variability of the depth- integrated Chl-a biomass in the euphotic zone (¾Chl-a in terms of an overall "environmental condition" over a 50 km upwelling sensitive coastal strip, revisiting published and unpublished Chl-a ship (Cship = Chl-a + Phaeopigments data. All possible "environmental conditions" combinations were further ranked into seven "environmental indices" ranging from 0 ("absolutely cold" to 6 ("absolutely warm". Out of 332 samples of ¾Chl-a, 198/134 were obtained during active/relaxed upwelling conditions from which 24/38 and 30/36 samples were associated with the simultaneous occurrence of at least two "cold"/"warm" phases of the three environmental cycles ("cold"/"warm" environmental conditions, respectively. Lower ¾Chl-a values during "cold" and "warm" environmental conditions relative to the "neutral" ones reached statistical significance for both active and relaxed conditions (144/60 samples respectively. Higher turbulent mixing during "cold" environmental conditions and a deeper nutricline during "warm" ones would explain lower ¾Chl-a-values. Satellite chlorophyll (Csat data obtained in clear skies (active upwelling only, showed a similar distribution to those of ¾Chl-a when classified into the corresponding "environmental indices". These results suggest that during "neutral" (transitional "environmental conditions

  20. The effect of heat and smoke on the emergence of exotic and native seedlings in a Mediterranean fire-free matorral of central Chile Efecto del calor y el humo sobre la emergencia de plántulas exóticas y nativas en un matorral mediterráneo libre de fuego en Chile central



    Full Text Available We studied the effect of heat shock and wood-fueled smoke on the emergence of native and exotic plant species in soil samples obtained in an evergreen matorral of central Chile that has been free of fire for decades. It is located on the eastern foothills of the Andes Range in San Carlos de Apoquindo. Immediately after collection samples were dried and stored under laboratory conditions. For each two transect, ten samples were randomly chosen, and one of the following treatments was applied: (1 heat-shock treatment, (2 plant-produced smoke treatment, (3 combined heat-and-smoke treatment, and (4 control, corresponding to samples not subjected to treatment. Twenty-seven species, representing 13 families, emerged from the soil samples. The most abundant families were Asteraceae and Poaceae. All of the emerged species were herbaceous, and 18 species were exotic. Respect to general hypothesis, there is no evidence for the proposition that fire-free matorral has lower proportion of exotic and native species with fire-related cues than matorral with fires. Among the exotic and native, the mean number of species that emerged from soil samples did not change significantly with respect to the control for any of the treatments applied. Nevertheless, important species-specific responses were observed. Smoke and heat-smoke combination significantly increased the emergence of the exotic species Anthriscus caucalis. While smoke-related cues significantly increased the emergence of the exotic species Avena barbata, the emergence of the exotic Aphanes arvensis and the native Bromus berteroanus decreases. For several species our results showed inconsistent responses to fire-related cues compared to those reported in the literature. We suggest that these differences might be related with the fire-history in the populations, an important issue poorly acknowledge in the literature.Nosotros estudiamos el efecto del golpe de calor y del humo de la combustión de

  1. Spatio-temporal distribution of spionids (Polychaeta-Spionidae in an estuarine system in south-central Chile Distribución espacio-temporal de los espiónidos (Polychaeta-Spionidae en un sistema de estuarios del centro sur de Chile



    Full Text Available This study is based on the identification and distribution of spionid polychaetes in relation to abiotic characteristics of the environment at the mouth of the Valdivia-Tornagaleones estuary in south-central Chile. Four samplings were carried out in 2005, in which eight species were identified including Aquilaspio peruana, Boccardia polybranchia, Carazziella carrascoi, Dipolydora socialis, Minuspio patagónica, Rhynchospio glutaea, Scolelepis quinquedentata and Spiophanes sp. As it is typical of other estuaries in south central Chile, spionids were an important component of the macroinfauna of the Valdivia estuary. The distribution of the Spionidae family in the system showed higher species richness in the outer reach of the estuary but higher abundance (number of specimens at the inner reach. The distributional pattern of the polychaetes did not vary throughout the year, exhibiting strong spatial zonation with three significantly different assemblages. Minuspio patagónica, A. peruana and C. carrascoi contributed to the similarity between these three groups, as well as to the formation of a general component in the macroinfauna. Sedimentological and depth variables, as well as sedimentary organic material were only marginally related to the distribution of spionids. Results showed that bottom salinity was the environmental variable responsible for spatial differentiation of spionids in the three groups, which permit to differentiate the outer-reach species from those in the internal area of the estuary. The significant contribution of spionids to the total component of macroinfauna in the studied area shows that these species are a significant component of the estuarine and transition areas in the southwest Pacific coast.El estudio se desarrolla en base a la identificación y distribución de Spionidae y su relación con las características abióticas del medio, en la desembocadura del sistema estuarial Valdivia-Tornagaleones (Chile. Se

  2. Effect of Compost Application on Some Properties of a Volcanic Soil from Central South Chile Efecto de la Aplicación de Compost sobre Algunas Propiedades de un Suelo Volcánico de La Región Centro-Sur de Chile

    Pedro José Valarini


    Full Text Available Soil compost application is a common soil management practice used by small farmers of Central-South Chile that produces positive effects on soil properties and also promotes presence and activity of arbuscular mycorrhizal fungi (AMF. This fungi form symbiosis with plant roots improving plant nutrition, as well as producing glomalin, a glycoprotein that has been associated with soil aggregation stability. Therefore, the aim of this study was to evaluate, in an Ultisol from Central-South Chile, the effect of different doses of compost on some soil characteristics at the end of the third year of a crop sequence including wheat (Triticum aestivum L., bean (Phaseolus vulgaris L., and grassland (Lolium multiflorum Lam. associated with Trifolium repens L.. Studied soil characteristics included chemical (pH, available-P, organic C, biological (C and N biomass, AMF spore number, root colonization percentage, mycelium length, and glomalin content, as well as physical parameters (water holding capacity [WHC], and water stable aggregates [WSA]. Results showed that, in general, compost application increased soil pH, mycorrizal roots, mycelium length, glomalin levels, and WSA. Significant relationships were found between C and N biomass, C biomass and WSA, C biomass and glomalin, WSA and WHC, among others. Results suggest that compost application to this type of soil is a feasible option as a fertilizer substitute, and a way to avoid soil erosion by small local farmers involved in organic agriculture.La aplicación de compost al suelo, práctica habitual en predios de pequeños agricultores de la región centro-sur de Chile, produce efectos positivos en sus propiedades y promueve la presencia y actividad de los hongos micorrícicos arbusculares (AMF. Estos hongos forman simbiosis con las raíces de las plantas mejorando su nutrición y además producen una glicoproteína llamada glomalina, la cual ha sido relacionada con la estabilidad de los agregados de

  3. Parasites of the Green-backed Firecrown (Sephanoides sephaniodes) in Chile Parásitos del picaflor chico (Sephanoides sephaniodes) en Chile

    Daniel González-Acuña; Carolina Silva; Marta Soto; Sergei Mironov; Lucila Moreno; González-Gómez, Paulina L.; Hasan Badrul; Mike Kinsella


    Gastrointestinal and external parasites from 12 Green-backed Firecrown (Sephanoides sephaniodes) were collected between January 2004 and December 2008 from the Biobío Region south-central Chile and Santiago (central Chile). Helminths collected included 1 trematode species (Mosesia sp.) and 1 cestode species (Hymenolepis trinidadensis). The mite Proctophyllodes huitzilopchtlii was the only ectoparasite species found. All these parasites represent new records for Chile and the first parasites r...

  4. La dieta y fauna de endoparásitos del pejesapo Gobiesox marmoratus Jenyns, 1842 (Pisces: Gobiesocidae en el litoral central de Chile están conectadas pero no correlacionadas Feeding habits and endoparasite fauna of the clingfish Gobiesox marmoratus Jenyns, 1842 (Pisces: Gobiesocidae on the central coast of Chile are intertwined, but not correlated

    M. Cecilia Pardo-Gandarillas


    similarity is documented in the composition of the endoparasitic fauna and the diet of the clingfish G. marmoratus Jenyns, 1842, between three localities off the central coast of Chile separated about 400 km from their nearest neighbor(s. Clingfish in the samples were similar between localities in total body length. The parasite fauna was composed by 16 metazoan taxa (including five Myxozoa. Parasites were found in 38.8 % of the 108 clingfish examined, whereas 32.4 % of the fish in the samples had stomach contents, where 37 prey items were recognized. The even rarer cases of co-occurrence of parasites and prey impeded the search of correlations between both type of variables, such as that between the dietary width and parasite richness. Composition of parasite infracommunities and diet changed along host ontogeny. The diet of juvenile and adult clingfish consisted mainly of amphipods, decapod crustaceans and mollusks at the three localities. The numerical descriptors of the diet and of infracommunities (total abundance, diversity and richness are similar between the localities and along the host ontogeny. The composition of the endoparasitic fauna necessarily depends on the diet of the clingfish, but there is no statistical correlation between both variables. This can be due to the small maximum body size reached by the adults, to the short length of the digestive tract, to the differences in the rate and frequency at which parasites and prey enter and stay in the hosts, to the level of taxonomic resolution attained in prey and/or parasites, and to having decided to include or not rare prey/parasites in the analyses

  5. Análisis operacional de dos flotas industriales en la pesquería de merluza común (Merluccius gayi gayi, región centro-sur de Chile Operational analysis of two industrial fleet in the Chilean hake (Merluccius gayi gayi fishery in the southern-central region of Chile

    Catterina Sobenes V.


    Full Text Available El trabajo tiene como objetivo analizar la actividad de dos flotas industriales (empresa A y empresa B que operan sobre la pesquería de merluza común en la región centro-sur de Chile. Para ello, se utilizó información histórica de la operación de la flota pesquera entre 1998 y 2002. Se evaluaron las zonas de pesca o caladeros según indicadores de efectividad, costo unitario, rentabilidad y utilidad. Las embarcaciones se seleccionaron acorde a indicadores de eficiencia operacional. Estos resultados fueron contrastados con los caladeros visitados y las embarcaciones utilizadas por las empresas, durante el período de estudio. La zona de pesca más adecuada, se determinó según los índices de eficiencia para 13 caladeros de la región centro-sur de Chile. Se observa que ambas empresas han seleccionado adecuadamente los caladeros Tomé al oeste (caladero 9, Tomé al este (caladero 8 y al sur de Punta Lavapié (caladero 10, que tienen los mejores índices de eficiencia. Respecto a la selección de la embarcación más adecuada, se efectuó un análisis de jerarquización de las embarcaciones, por cada empresa, mediante el análisis de anomalías de indicadores de eficiencia. Ambas empresas seleccionaron aquellas embarcaciones que obtuvieron los mejores indicadores de eficiencia. Para el caladero 9 el estudio propone que la empresa A opere con el pesquero de alta mar PAMa3 y la empresa B con el PAMb4. Sin embargo, en el caladero 10, la empresa A debe utilizar el PAMa5 y no el PAMa3 utilizado históricamente, y la empresa B debe continuar operando con el PAMb1 y PAMb2 como lo ha hecho durante el periodo analizadoThis work aims at analysing the operation of two industrial fishing fleets (company A and company B which works on the Chilean hake (Meluccis gayi gayi fishery in the southern-central region of Chile. For this reason, it was used the historical information of the fleet operation from the southern-central region from 1998 to 2002. The

  6. Rhizosphere Pseudomonas sp. strains reduce occurrence of pre- and post-emergence damping-off in chile and tomato in Central Himalayan region.

    Sharma, Alok; Wray, Victor; Johri, Bhavdish N


    Based on in vitro screening for PGP and anti-mycelial activity against three zoosporic pathogenic oomycetes, Pythium aphanidermatum 123, P. aphanidermatum 4746, and Phytophthora nicotianae 4747, seven bacterial isolates were selected for field trials on tomato and chile to test for plant growth promotion under natural and artificial disease-infested field sites in both winter and wet seasons. The effectiveness of isolates in the field trials correlated with the in vitro antagonism screening data. Pseudomonas sp. FQP PB-3, FQA PB-3 and GRP(3) showed substantial beneficial effects on plant growth promotion and lowered considerably the incidence of pre- and post-emergence damping-off in both the crops under various disease scenarios. For example, seed bacterization with these bacterial strains reduced pre-emergence-damping off by ca. 60-70% in the two natural sites, with and without histories of fungicide use in the winter season, and to a lesser extent, ca. 20-40%, in the warmer wet (high humidity; 85-92%) season. The suppression efficacy for post-emergence damping-off was less compared to pre-emergence damping-off although still significant (P > 0.05). Our data unambiguously show that screening of a large number of bacterial pool identifies promising isolates that show beneficial effects on all stages of plant growth in natural oomycete-infested regimes. PMID:17160408

  7. Determination of potential risk of heat stress of cattle in four locations of Central and Southern Chile Determinación del riesgo potencial de estrés térmico del ganado bovino en cuatro localidades del centro y sur de Chile

    RA Arias


    Full Text Available Meteorological data from December to January of years 1999 to 2007 from weather stations located in four localities in Chile (Curicó, Chillán, Temuco and Osorno were used to calculate the adjusted temperature-humidity index (THIadj-max. Climate variables used to calculate the index were: wind speed, air temperature, relative humidity and an estimated value of solar radiation. When the values of THIadj-max were greater than 75, those days were considered as “alert” and as potential risk of heat stress in cattle. Additionally, the impact of climate on animal production was assessed by means of potential losses in milk production for each locality estimated by two equations. The localities of Curicó and Chillán presented similar values of THIadj-max (79.4 and 79.1, respectively, and both were higher than those for Temuco and Osorno (77.1 and 68.1, respectively, P 75 was greater in the Central region. In addition, the estimated mean milk production loss was greater in the Central regions (1.5 to 4.3 and 1.2 to 3.1 L*cow-1*d-1 for Curicó and Chillán, respectively. Conversely, the Southern regions, Temuco and Osorno, presented lower potential losses with 0.9 to 2.6 and 0.1 to 0.6 L*cow-1*d-1, respectively. In conclusion, the potential risk of heat stress of cattle seems greater in Curicó and Chillán, moderate in Temuco and minimum in Osorno. Additional research is needed in the order to quantify the impacts of environmental conditions in productivity and welfare of cattle in Chile.Datos climáticos del periodo diciembre a febrero de los años 1999 al 2007 provenientes de estaciones meteorológicas situadas en Curicó, Chillán, Temuco y Osorno fueron utilizados para calcular un índice temperatura-humedad ajustado por el efecto del viento y de la radiación (THIadj-max. Las variables climáticas utilizadas para calcular este índice incluyeron: velocidad del viento, temperatura máxima del aire, humedad relativa y un valor estimado de la

  8. Caracterización de agregaciones de merluza de cola (Macruronus magellanicus en la zona centro-sur de Chile Characterization of Chilean hoki (Macruronus magellanicus aggregations off central-southern Chile

    Dante Queirolo


    Full Text Available Se realizó la caracterización mensual de las agregaciones de merluza de cola usando registros acústicos obtenidos por equipos SIMRAD EK60 y ES60 a bordo de tres embarcaciones multipropósito que operaron en la Unidad de Pesquería Centro-Sur durante el año 2003, para lo cual se emplearon descriptores morfológicos y batimétricos. En cuanto a su morfología, las agregaciones mostraron una amplia variabilidad, explicada por su nivel de cohesión y tendencia a formar agregaciones de gran extensión horizontal, mientras que batimétricamente se determinó que el 90% de éstas se ubicaron preferentemente entre 300 y 450 m. Existe evidencia de asociación entre diversos descriptores y estos a su vez con otros factores como talla media, temperatura del agua, latitud y mes, lo que permite describir apropiadamente la forma de las agregaciones y su ubicación en la columna de agua. Algunas relaciones relevantes corresponden a: profundidad de las agregaciones respecto a la profundidad del fondo (r = 0,55, altitud de las agregaciones respecto a la profundidad del fondo (r = 0,72, altitud de las agregaciones respecto al índice de profundidad relativa (r = -0,98 y profundidad de las agregaciones respecto a la talla media (r = 0,66.A monthly characterization of Chilean hoki aggregations was done using acoustic records ob-tained with SIMRAD EK60 and ES60 devices aboard three multipurpose vessels that operated in the central-southern fishery unit during 2003; this considered morphological and bathymetric descriptors. The wide mor-phological variation of the aggregations was explained by their cohesión level and tendency to form large horizontal aggregations whereas, bathymetrically, 90% of the aggregations were located between 300 and 450 m. Evidence of associations between various descriptors was found, and these were, in turn, associated with other factors such as mean size, water temperature, latitude, and month, allowing an adequate description of the

  9. A small, new gerbil-mouse Eligmodontia (Rodentia: Cricetidae) from dunes at the coasts and deserts of north-central Chile: molecular, chromosomic, and morphological analyses.

    Spotorno, Angel E; Zuleta, Carlos; Walker, Laura I; Manriquez, German; Valladares, Pablo; Marin, Juan C


    A small, new species of gerbil rodents of the genus Eligmodontia from the southwestern dunes of the Atacama Desert in northern Chile is described; the genus had not been reported for this western lowland region. Our description is based on cytogenetic and molecular data, as well as cranial and external morphology. In order to support this hypothesis, we studied 27 specimens captured in Playa Los Choros (Coquimbo) and Copiapó (Atacama), comparing them with samples of all the extant species of the genus. Nineteen individuals consistently showed 2N=50, FN=48, with telocentric chromosomes and G-bands identical to those of the geographically northeastern E. hirtipes; these two groups were geographically separated by E. puerulus (2N = 34, FN = 48). The phylogenetic analysis of 56 Eligmodontia cytochrome-b gene sequences yielded a maximum-likelihood phylogenetic tree where the new species formed a divergent and well-supported clade within the genus, which was also confirmed by unweighted parsimony, minimum evolution, and Bayesian analyses. The new species has K2P genetic distances of 12.8% from the geographically distant E. hirtipes, and 10.3% from E. puerulus. Axes 1 and 2 of Principal Component Analysis based on 12 body and skull measurements clearly separated the new species, the latter having a smaller head+body length (70.6 +/- 3.4 mm, n = 17) and lower weight (11.9 +/- 1.9 g, n = 20). We provide strong evidence to recognize a distinct new western lineage within Eligmodontia genus, Eligmodontia dunaris sp. nov., for which we give a complete taxonomic description and a hypothetical biogeographic scenario. The new species should be considered endangered, due to its level of endemism, its low population numbers (which can be occasionally increased after a blooming desert) and its fragile dry habitat patchily distributed near the Atacama Desert. PMID:25250459

  10. Depositación atmosférica de nitrógeno en un transecto valle longitudinal-cordillera de Los Andes, centro-sur de Chile Atmospheric deposition of nitrogen in a transect from the Central Valley to Cordillera de Los Andes, south-central Chile



    El aumento de las actividades agrícolas y ganaderas en el centro-sur de Chile puede producir elevadas emisiones de nitrógeno hacia la atmósfera (mayormente NH3). El amoniaco es transportado por corrientes de aire y depositado en el suelo y vegetación. El presente estudio evalúa la depositación atmosférica de compuestos nitrogenados (NO3- y NH4+) en la química de las precipitaciones en un transecto altitudinal de 66 km, desde los alrededores de la ciudad de Osorno (40º 35' S, 72º 57' O, 55 m d...

  11. Radioactive wastes management development in Chile

    A Facility for immobilizing and conditioning of radioactive wastes generated in Chile, has recently started in operation. It is a Radioactive Wastes Treatment Plant, RWTP, whose owner is Comision Chilena de Energia Nuclear, CCHEN. A Storgement Building of Conditioned Wastes accomplishes the facility for medium and low level activity wastes. The Project has been carried with participation of chilean professionals at CCHEN and Technical Assistance of International Atomic Energy Agency, IAEA. Processes developed are volume reduction by compaction; immobilization by cementation and conditioning. Equipment has been selected to process radioactive wastes into a 200 liters drum, in which wastes are definitively conditioned, avoiding exposition and contamination risks. The Plant has capacity to treat low and medium activity radioactive wastes produced in Chile due to Reactor Experimental No. 1 operation, and annex Laboratories in Nuclear Research Centers, as also those produced by users of nuclear techniques in Industries, Hospitals, Research Centers and Universities, in the whole country. With the infrastructure developed in Chile, a centralization of Radioactive Wastes Management activities is achieved. A data base system helps to control and register radioactive wastes arising in Chile. Generation of radioactive wastes in Chile, has found solution for the present production and that of near future

  12. Late Mesozoic to Paleogene stratigraphy of the Salar de Atacama Basin, Antofagasta, Northern Chile: Implications for the tectonic evolution of the Central Andes

    Mpodozis, Constantino; Arriagada, César; Basso, Matilde; Roperch, Pierrick; Cobbold, Peter; Reich, Martin


    The Salar de Atacama basin, the largest "pre-Andean" basin in Northern Chile, was formed in the early Late Cretaceous as a consequence of the tectonic closure and inversion of the Jurassic-Early Cretaceous Tarapacá back arc basin. Inversion led to uplift of the Cordillera de Domeyko (CD), a thick-skinned basement range bounded by a system of reverse faults and blind thrusts with alternating vergence along strike. The almost 6000-m-thick, upper Cretaceous to lower Paleocene sequences (Purilactis Group) infilling the Salar de Atacama basin reflects rapid local subsidence to the east of the CD. Its oldest outcropping unit (Tonel Formation) comprises more than 1000 m of continental red sandstones and evaporites, which began to accumulate as syntectonic growth strata during the initial stages of CD uplift. Tonel strata are capped by almost 3000 m of sandstones and conglomerates of western provenance, representing the sedimentary response to renewed pulses of tectonic shortening, which were deposited in alluvial fan, fluvial and eolian settings together with minor lacustrine mudstone (Purilactis Formation). These are covered by 500 m of coarse, proximal alluvial fan conglomerates (Barros Arana Formation). The top of the Purilactis Group consists of Maastrichtian-Danian alkaline lava and minor welded tuffs and red beds (Cerro Totola Formation: 70-64 Ma K/Ar) deposited during an interval of tectonic quiescence when the El Molino-Yacoraite Late Cretaceous sea covered large tracts of the nearby Altiplano-Puna domain. Limestones interbedded with the Totola volcanics indicate that this marine incursion advanced westwards to reach the eastern CD slope. CD shortening in the Late Cretaceous was accompanied by volcanism and continental sedimentation in fault bounded basins associated to strike slip along the north Chilean magmatic arc to the west of the CD domain, indicating that oblique plate convergence prevailed during the Late Cretaceous. Oblique convergence seems to have

  13. Las áreas de filtración de metano constituyen zonas de agregación del bacalao de profundidad (Dissostichus eleginoides frente a Chile central?

    Javier Sellanes


    Full Text Available Se presenta los resultados de dos campanas (invierno y verano de pesca de bacalao de profundidad (Dissostichus eleginoides, realizadas sobre un área de filtración de metano (AFM y un sitio aledano utilizado como control. Estas fueron desarrolladas con el objetivo de determinar si las AFM constituyen sitios de agregación de D. eleginoides. Para cada área se registró la captura promedio, el rendimiento de pesca y se determinó índices de abundancia y diversidad incluyendo la fauna capturada incidentalmente. Los ejemplares de bacalao de profundidad capturados en ambos sitios fueron sexados, medidos y pesados. Adicionalmente, se presentan imágenes tomadas in situ, dentro del AFM, que documentan la presencia tanto de D. eleginoides como aparejos de pesca perdidos utilizados en su captura frente a la costa de Concepción. Las mayores capturas y rendimientos fueron observadas en el AFM, con valores promedio de 56,2 kg por lance de pesca y rendimientos promedios de 80,3 g/anzuelo, siendo significativamente mayores en comparación al sitio control. La campana de pesca realizada en invierno registra mayores capturas y rendimientos en ambas áreas. La composición faunística evaluada a través de los índices comunitarios, indica diferencias significativas entre sitios, registrándose un mayor número de especies de fauna acompanante en el AFM, en comparación con el sitio control (18 y 14 especies, respectivamente. Se hipotetiza que la mayor abundancia de bacalao de profundidad en el AFM, estaría relacionada tanto con la mayor heterogeneidad espacial, dada por la presencia de arrecifes de carbonatos autigénicos, como con la disponibilidad de presas, constituyendo estos sitios como zonas de alimentación. El presente trabajo entrega información tendiente a establecer el rol ecológico de las AFM y la fauna asociada a ellas en ambientes batiales frente a Chile.

  14. Geometry of the inverted Cretaceous Chañarcillo Basin based on 2-D gravity and field data. An approach to the structure of the western Central Andes of northern Chile

    F. Martínez


    Full Text Available This paper discusses an integrated approach that provides new ideas about the structural geometry of the NNE-striking, Cretaceous Chañarcillo Basin located along the eastern Coastal Cordillera in the western Central Andes of northern Chile (27–28° S. The results obtained from the integration of two transverse (E–W gravity profiles with previous geological information, show that the architecture of this basin is defined by a large NNE–SSE-trending and east-vergent anticline ("Tierra Amarilla Anticlinorium", which is related to the positive reactivation of a former Cretaceous normal fault (Elisa de Bordos Master Fault. Moreover, intercalations of high and low gravity anomalies and steep gravity gradients reveal a set of buried, west-tilted half-grabens associated with a synthetic normal fault pattern. These results, together with the uplift and folding style of the Cretaceous syn-rift recognized within the basin, suggest that their complete structural geometry could be explained by an inverted fault system linked to the shortening of pre-existing Cretaceous normal fault systems. Ages of the synorogenic deposits exposed unconformably over the frontal limb of the Tierra Amarilla Anticlinorium confirm a Late Cretaceous age for the Andean deformation and tectonic inversion of the basin.


    R. A. A. Bran


    Full Text Available Los recursos fitogenéticos son la base de la seguridad alimentaria de la población mundial. México constituye uno de los centros de origen y diversidad de varias especies vegetales, entre ellas diversos tipos de Capsicum. Sin embargo, el mal manejo de ellos está afectando su conservación, fundamentalmente por la acción depredadora del hombre, el uso excesivo de agroquímicos y la deforestación; todo esto explica el esfuerzo de las instituciones científicas y gubernamentales por su cuidado y conservación. El trabajo se realizó en cinco municipios de la región Frailesca de la Depresión Central de Chiapas, México. Se inició con la aplicación de una encuesta a 386 pobladores de la región rural. La información fue evaluada mediante el análisis de frecuencia. Los resultados demostraron que la población rural tiene conocimientos sobre la utilización de los chiles silvestres y semisilvestres como alimento y condimento, no así en los aspectos relacionados con su conservación, la cual es realizada por los campesinos en pequeños huertos.

  16. Fundacion Chile Incubator : Chile Case Study

    World Bank


    Foundation Chile was created in 1976 as a nonprofit governed jointly by the Chilean government and a large American conglomerate. It proactively introduces technology innovations and develops companies in target industries including agribusiness, marine resources, forestry, environment and chemical metrology, human capital, and information and communication technologies. Among its successe...

  17. U-Pb, 40Ar-39Ar and fission track geochronology of the Early Cretaceous Caleu pluton and its volcanic envelope, Coastal Range of central Chile: tectonic and metamorphic implications

    The Caleu pluton is emplaced into a thick Early Cretaceous volcano-sedimentary succession deposited in a subsiding basin (Vergara et al., 1995). This succession includes the Ocoite Group (Aguirre et al., 1989) and the Las Chilcas Formation. At the latitude of Santiago (33oS) the Ocoite Group is represented by a c. 10 km thick pile, whose lower third corresponds to the volcanic-sedimentary Lo Prado Formation (Valanginian - Hauterivian). The central part of the pile corresponds to the Veta Negra Formation (Barremian - Albian), which is made up of continental porphyritic basalts and basaltic andesites and continental flow breccias. The Las Chilcas Formation (Mid-Albian) consists of a succession of limestones, red sandstones, rhyolitic tuff, and thick strata of coarse-grained conglomerates. The Early Cretaceous basalts and basaltic andesites of the Veta Negra Formation and the granitoids of the Caleu pluton are rocks derived from one of the most isotopically (Sr-Nd) depleted source identified in Andean history (cf. Vergara et al., 1995; Parada et al., 2001). These rocks exhibit high-K to shoshonitic affinity, and are associated with a regional extensional regime (Levi et al., 1989; Vergara et al., 1995), probably triggered by asthenospheric upwelling after a lithospheric delamination (Parada et al., 1999). As a consequence of the extensional regime, low-grade burial metamorphism developed in the rocks of the volcano sedimentary sequences. The aim of this study is to provide evidence from U-Pb (zircon), 40Ar-39Ar (hornblende, biotite and plagioclase), and apatite fission track dating of the Caleu pluton, and from 40Ar-39Ar (plagioclase, sericite and adularia) ages of the spatially related mafic volcanic rocks of the Veta Negra Formation, about the timing of magmatism, subsolidus cooling of the pluton and metamorphism, and the tectonic processes that took place during a key period of the Andean geological evolution in central Chile (au)

  18. Geochronology (40Ar/39Ar, K-Ar and He-exposure ages of Cenozoic magmatic rocks from Northern Chile (18-22°S: implications for magmatism and tectonic evolution of the central Andes

    Gerhard Wörner


    Full Text Available K-Ar and Ar/Ar ages from magmatic rocks of northern Chile (18-22°S describe duration and extent of the Tertiary and Quaternary magmatic evolution and date major tectonic events in northernmost Chile. This paper summarizes new K-Ar and Ar-Ar mineral and whole rock ages for intrusive rocks from the Precordillera, Tertiary ignimbrites and andesitic stratovolcanoes from the Western Andean Escarpment at 18°S (WARP and the volcanic front. Intrusive rocks of the Precordillera (Quebrada Paguana, Quebrada Blanca, Quebrada Choja, Quebrada Guatacondo, Cerro Chandacolla represent the Cretaceous to Eocene magmatic arc system and gave ages between 45 and 35 Ma. Younger ages on intrusive rocks are invariably caused by deuteric alteration. Ignimbrites of the Putani and Oxaya formations gave Ar-Ar sanidine ages around 24.2 to 24.8 Ma and 22.8 to 19.4 Ma, respectively. Andesitic stratovolcanoes, which directly overlie Oxaya ignimbrites east of the Western Cordillera gave ages of 20.3 Ma (Cordon Quevilque to 9.0 Ma (Cerro Margarita. Samples from the Miocene to Pleistocene arc system on the Chilean Altiplano underlying the volcanoes of the active volcanic front have been dated between 10.5 to ~3 Ma. A widespread ignimbrite can be correlated from the Lauca basin to the Pacific coast and to the east to occurrences of near Pérez. Repeated Ar-Ar sanidine dating of the Lauca-Pérez-ignimbrite resulted in highly concordant ages of 2.71±0.25 Ma, 2.72 Ma±0.01 Ma, and 2.73±0.11 Ma. Rocks from the active chain (Volcanic Cordillera gave ages younger than 0.9 Ma (Volcán Irruputuncu, Volcán Olca, Volcán Aucanquilcha, Volcán Ollagüe, Volcán Poruñita. These new data are used to constrain Miocene stratigraphy and tectonic movements as well as the timing of uplift and sedimentary response at the Western Andean Escarpment within the framework of the tectonic evolution of the Central AndesGeocronología (49Ar/39Ar, K-Ar y edades He de exposición de rocas cenozoicas del

  19. Copper Bioleaching in Chile

    Juan Carlos Gentina; Fernando Acevedo


    Chile has a great tradition of producing and exporting copper. Over the last several decades, it has become the first producer on an international level. Its copper reserves are also the most important on the planet. However, after years of mineral exploitation, the ease of extracting copper oxides and ore copper content has diminished. To keep the production level high, the introduction of new technologies has become necessary. One that has been successful is bioleaching. Chile had the first...

  20. Marine Energy in Chile

    Antonio Levy


    This is the first issue of a new series dedicated to deliver concise information on energy innovation published by the Energy Innovation Center at the IDB. This issue offers a primer on the potential for marine energy in Chile. The ocean is increasingly recognized as a viable source of renewable energy, and Chile, with its long coastline, powerful waves and tidal currents, has captured the attention of marine energy proponents. While harvesting this source of energy would increase sustainabil...

  1. Research training in dental undergraduate curriculum in Chile.

    Ximena Moreno


    ABSTRACT Research plays a central role in professional training in dentistry. There is a clear recommendation to include a minimum training in biomedical research at undergraduate level. In Chile, there is no standardized curriculum structure including research training for undergraduate students. Objective: To describe the presence of research courses in the undergraduate dental curriculum in Chile during 2014. Methodology: A descriptive cross-sectional study. The curriculum for all Chilean...

  2. Characterization and comparison of microphytoplankton biomass in the lower reaches of the Biobío River and the adjacent coastal area off Central Chile during autumn-winter conditions Caracterización y comparación de la biomasa microfitoplanctónica en el curso inferior del río Biobío y la zona costera adyacente frente a Chile Central durante condiciones de otoño-invierño

    Bárbara Léniz


    Full Text Available The Biobío River in central Chile is the third largest watershed and second largest river in Chile in terms of discharge volume. Three sampling campaigns were made in the lower reaches of the river and the adjacent coastal ocean to evaluate the influence of the river plume on the physical/chemical conditions and the abundance/biomass of microphytoplankton during autumn-winter conditions. In addition, a preliminary quantification of riverine nutrients, dissolved silica, and phytoplankton carbon flux to the adjacent ocean was also conducted. High nitrate (ño3- and silicic acid (Si(OH4 concentration (>18 and 50 μΜ, respectively was observed in the lower reaches of the river during all field campaigns. Si(OH4 was even high in surface river plume waters. Hydrographic conditions indicate that river plume waters were piled coastward, and they could drove to the south at the Arauco Gulf. In all sampling, highest microphytoplankton biomass (>5000 μgC m-3 was associated to the lower reaches of the river and river plume waters as they were moving southward. During autumn-winter conditions a significant flux of phytoplankton carbon and nutrients to the adjacent coastal ocean also played an important role in the high biological productivity of this coastal upwelling area. These preliminary results evidence the need to conduct large-term studies, which should consider the importance of these allochthoñous carbon sources in global carbon budgets and coastal food-web models.El río Biobío, en la zona central de Chile es la tercera cuenca más grande y segundo río más grande de Chile en térmiños de volumen de descarga de agua dulce. Se realizaron tres campanas de muestreo en el curso inferior del río y la zona costera adyacente para evaluar la influencia de la pluma del río Biobío, en las condiciones físicas/químicas relacionadas con la abundancia/biomasa del microfitoplancton en condiciones de otoño-invierño. Además, se realizó una

  3. Comunidad ectomicorrícica en una cronosecuencia de Pinus radiata (Pinophyta: Pinaceae de la zona de transición climática mediterráneo-templada de Chile central The ectomycorrhizal community in a chronosequence of Pinus radiata (Pinophyta: Pinaceae of the transitional Mediterranean-temperate climatic zone of central Chile



    Full Text Available En ecosistemas naturales y plantaciones, las coníferas establecen asociaciones mutualistas con una comunidad diversa de hongos micorrícicos. El estudio de este tema en Sudamérica es aún incipiente, y no existen antecedentes sobre la dinámica temporal de esta comunidad, y menos de sus potenciales causas, a pesar de su importancia para un país forestal como Chile. En el presente trabajo se evaluó la dinámica de la comunidad ectomicorrícica, identificando y cuantificando los hongos formadores de esta asociación en raíces finas de Pinus radiata en plantaciones de 3, 10 y 20 años. Los resultados confirman que la comunidad ectomicorrícica de P. radiata cambia con la edad de los árboles, la cual difiere más bien en el patrón de dominancia que en la riqueza de especies, separándose un primer grupo de árboles de 3 y 10 años de un segundo grupo de 20 años. Un total de once morfotipos de micorrizas fueron diferenciados. Cuatro de ellos, identificados como Hebeloma crustuliniforme, Inocybe sp., Russula sardonia y Pinirhiza spinulosa, fueron los más abundantes (77, 29, 78 y 8 % respectivamente, mientras las otras se encontraron colonizando menos de 100 puntas de raíz (In natural forest ecosystems and plantations, most trees live in mutualistic association with mycorrhizal fungi. Studies of this association in South America are still scarce, especially when referring to the causes of temporal dynamics of this symbiotic community, despite its importance in countries with a thriving forestry industry like Chile. This study evaluates the dynamics of the ectomycorrhizal community of Pinus radiata stands of 3, 10 and 20 years of age, identifying and quantifying the most common fungal colonizers of fine roots in each age class. The results confirm that the mycobiont community changes with host tree age but that age classes differ in dominance patterns rather than in species richness, with the three- and ten-year-old tree cohorts forming a

  4. The role of sediment composition and behavior under dynamic loading conditions on slope failure initiation: a study of a subaqueous landslide in earthquake-prone South-Central Chile

    Wiemer, Gauvain; Moernaut, Jasper; Stark, Nina; Kempf, Philipp; De Batist, Marc; Pino, Mario; Urrutia, Roberto; de Guevara, Bruno Ladrón; Strasser, Michael; Kopf, Achim


    Subaqueous slope failure mechanisms are still poorly understood partly because they are difficult to study due to the remote location of submarine landslides. Landslides in lakes are smaller in size and more readily accessible and therefore represent a good alternative to their marine counterparts. Lake Villarrica, located in South-Central Chile, experienced significant slope failure and serves here as an exemplary study area for subaqueous landslide initiation mechanisms in tectonically active settings. Coring and CPTU testing were undertaken with the MARUM free-fall CPTU deployed adjacent to the coring sites where all lithological units involved in the slope failure were sampled. Using geotechnical methods such as pseudo-static factor of safety analysis and cyclic triaxial testing, three types of soils (i.e., diatomaceous ooze, volcanic ash, and quick clay) were analyzed for their role in slope failure, and earthquake shaking was identified as the primary trigger mechanism. The investigated landslide consisted of two distinct phases. During the first phase, slope failure was initiated above a tephra layer. In the second phase, retrogression led to the shoreward extension of the slide scarp along a second failure plane located in a stratigraphically deeper, extremely sensitive lithology (i.e., quick clay). Results show that liquefaction of buried tephra layers was unlikely, but such layers might still have contributed to a reduction in shear strength along the contact area with the neighboring sediment. Furthermore, cyclic shaking-induced pore pressure in diatomaceous ooze may be similar to that in granular soils. We generally infer that failure mechanisms observed in this study are equally important for landslide initiation in submarine settings as diatomaceous ooze intercalated with volcanic ash may be abundantly present along active continental margins.

  5. New time-constraints on provenance, metamorphism and exhumation of the Bahía Mansa Metamorphic Complex on the Main Chiloé Island, south-central Chile Nuevas restricciones temporales sobre proveniencia, metamorfismo y exhumación del Complejo Metamórfico Bahía Mansa en la Isla Grande de Chiloé, centro-sur de Chile

    Paul Duhart


    Full Text Available The Coastal Ranges in the western part of the Chiloé Archipelago represent an emerged forearc high at the subduction front of south-central Chile. Prior to the Cenozoic framework of the subducting Farallón and Nazca plates beneath the South American plate, the history of the metamorphic basement in the Coastal Ranges involves episodes of subduction and/or accretion of oceanic and ensialic material along the proto-Pacific margin of Gondwana. Along different segments of the Main Chiloé Island the thermal record of the metamorphic basement rocks includes regional metamorphism, exhumation and finally magmatism. Detrital zircons conventional U-Pb ages from a pelitic schist of the Central Segment of the Main Chiloé Island constrain the maximum possible sedimentation age to the Carboniferous (310 Ma. Other concordant zircon fractions (360, 390 and 412 Ma suggest Ordovician primary sources. The sedimentary provenance of zircons could correspond to continental magmatic rocks of similar ages presently exposed in adjacent areas such as Nahuelbuta Mountains and Principal Cordillera and, additionally, from distal areas in the North-Patagonian and Deseado massifs. Widespread metamorphism in greenschist facies is well represented in the basement unit of the Main Chiloé Island. K-Ar and 40Ar/39Ar cooling ages in white mica range between 245 to 220 Ma, interpreted as near the peak of metamorphism during Middle to early Late Triassic times. Zircon and apatite fission-track (FT central ages in metamorphic rocks range from Late Jurassic (ca. 156 Ma to Eocene (ca. 38 Ma and are accompanied by relatively large dispersions. The modelling of the zircon FT single-grain age distributions depicts younger deconvoluted Late Cretaceous peak (ca. 80 Ma and the apatite modelling shows two populations, an older Late Cretaceous peak (ca. 64-91 Ma and a younger Eocene peak (ca. 3 8-5 3 Ma. The zircon and apatite Late Cretaceous peaks together with the presence of a marine

  6. Evolución tectónica, paleogeográfica y metalogénica durante el Cenozoico en los Andes de Chile norte y central e implicaciones para las regiones adyacentes de Bolivia y Argentina

    Reynaldo Charrier


    Full Text Available La orogenia incaica dio origen a un importante relieve en el Eoceno Medio, el que se concentró en el ámbito del arco magmático precedente, la Cordillera Incaica. Este relieve positivo de orientación NNE se extendió desde el sur de Perú hasta la región central de Chile y separó dos dominios paleogeográficos que tuvieron evoluciones diferentes durante el resto del Cenozoico. El dominio occidental se caracterizó por el predominio de procesos de erosión y sedimentación. En el dominio oriental también existieron importantes episodios de erosión que originaron depósitos que se encuentran en la vertiente oriental de la cadena en la actualidad y presentan una cronología comparable con la de los depósitos del dominio occidental. Sin embargo, la evolución se caracterizó por presentar, a partir del Eoceno Tardío, diferencias al norte y sur de los ~27ºS. Al norte de esa latitud, en el ámbito del Altiplano-Puna, el arco magmático se mantuvo aproximadamente en la misma posición, coincidente con la del arco actual, y estuvo bordeado por una cuenca de antepaís de retroarco; mientras que, al sur de ~27ºS, se desarrollaron sucesivos arcos magmáticos con una marcada migración hacia el este. El arco magmático del Eoceno Tardío al Oligoceno Tardío - Mioceno Temprano se caracterizó por el desarrollo de una amplia cuenca extensional de intra-arco, la cuenca de Abanico. En esta cuenca se acumularon hasta 3.000 m de rocas volcánicas, volcaniclásticas y, subordinadamente, sedimentarias. A partir del límite oligoceno-mioceno, tuvo lugar un nuevo evento compresivo a lo largo de todo el orógeno que rejuveneció el núcleo de la Cordillera Incaica e invirtió la cuenca de Abanico permitiendo la generación de abundantes depósitos sintectónicos a ambos lados de los nuevos relieves. El inicio de este evento coincide con la orogenia pehuenche, los pulsos compresivos se mantuvieron hasta el Plioceno Temprano. En el Mioceno Temprano a Medio

  7. Structural Volatility in Chile: A Policy Report

    Ricardo J. Caballero


    This paper identifies Chile's economic weaknesses and offers policy recommendations for increasing stability. Current problems include weak international financial links, a Central Bank mandate that is ill-designed to deal with terms of trade shocks, a propensity to waste scarce liquidity in the banking system; and limited development of financial markets. The paper's policy recommendations include improving external financial links, molding terms of trade contingencies into anti-cyclical pol...

  8. Epoca reproductiva y talla media de primera madurez sexual de Strangomera bentincki y Engraulis ringens en el período 1993-1997, en la zona centro-sur de Chile Reproductive period and mean size at first maturity for Strangomera bentincki and Engraulis ringens from 1993 to 1997 off central-southern Chile

    Luis Cubillos S.


    . Lm50% was determined on the basis of 50% of mature females criteria using a logistic equation fitted to observed data. The month at maximum GSI, between July and September, has the lowest interannual variability, i.e. coefficients of variation of 5.1% y 14.6% for S. bentincki and E. ringens respectively. The month at secondary maximum GSI presented coefficients of variation of 45% for S. bentincki and of 35.3% for E. ringens. Lm50% was estimated in 10 cm TL for S. bentincki and 11.5 cm for E. ringens. The Lm50% of S. bentincki is achieved in July, at the end of the first year of life, while the Lm50% of E. ringens is achieved in February, at about 1.5 year old. It is postulated that the populational reproductive period for both species, occurring in August during winter time, is a consequence of the adaptation to the seasonal coastal upwelling ecosystem off central-southern Chile. A higher productivity ( in the coastal waters can be found as a consequence of the occurrence of upwelling events from middle September to late March. Under this hypothesis, larval stages and juveniles could find good conditions for growth and survival during spring and summer time, and adults could gain energy that could be used in gonad maturation for the reproduction during winter time, the less-productive season

  9. Efecto de la fragmentación forestal sobre la estructura vegetacional de las poblaciones amenazadas de Legrandia concinna (Myrtaceae del centro-sur de Chile Effect of forest fragmentation on vegetation structure of Legrandia concinna (Myrtaceae threatened populations in south-central Chile



    tiempo a fin de evaluar la efectividad de determinadas estrategias de conservación para estas poblacionesHabitat fragmentation is one of the main threats to ecosystems integrity. In this study we assessed the influence of forest fragmentation on vegetation structure of populations of tree specie Legrandia concinna in south-central Chile. Occupancy pattern of Legrandia populations in remaining fragments of native forests was described, and relationship between landscape indices and vegetation structure variables were evaluated. Landscape indices, such as area, proximity mean index, shape and edge distance to fragment were applied to forest cover maps generated from a Landsat ETM+ satellite scene for the year 2001. Results showed high predominance of reduced size fragments, high isolation levels and regulars shapes of the fragments. Occupancy pattern suggests that Legrandia populations are found mainly in small and more isolated fragments. No significant difference was found between fragment distribution with and without presence of Legrandia related to size and isolation. However, we found that size, isolation and distance to fragment edge are significantly related to the presence of this specie. As conservation measures for this specie, we propose to include populations with high disappearance risk in protected areas, promote ex situ conservation and set up a monitoring program. This study sets a precedent related by linking landscape scale information obtained from satellite imagery and vegetation structure information measured in the field with conservation status of threatened populations. This innovative method allows monitoring changes over time to assess effectiveness of conservation strategies for these populations

  10. Análisis de las tasas de captura de jurel (Trachurus symmetricus en la zona centro-sur de Chile (1987-1999 Jack mackerel (Trachurus symmetricus catch rate analysis in the central-south of Chile (1987-1999

    Claudio Gatica


    Full Text Available Se analizaron los cambios en la Captura por Unidad de Esfuerzo (CPUE de la pesquería industrial de cerco de jurel (Trachurus symmetricus en la zona centro-sur de Chile entre 1987 y 1999. Se utilizaron dos unidades de esfuerzo de pesca para calcular las tasas de captura: días fuera de puerto y viajes con pesca. La flota se clasificó en cuatro estratos homogéneos mediante Análisis de Componentes Principales (ACP, utilizando una matriz de correlación de variables técnico-operacionales. Los dos primeros ejes del ACP explicaron 87,8% de la varianza, debido a la naturaleza altamente autocorrelacionada de las variables. Los estratos identificados se utilizaron como variables categóricas para estandarizar la CPUE a través de un Modelo Lineal General (MLG, previa transformación logarítmica de la CPUE. Los modelos ajustados a los datos explicaron sobre un 64% de la variabilidad observada, siendo el estrato el que explicó un mayor porcentaje de variabilidad: 24,6% en el caso de la CPUE basada en los días fuera de puerto y 42,6% en la CPUE basada en los viajes con pesca. Las dos series de CPUE indicaron diferentes tendencias entre 1987 y 1993, pero coincidieron en señalar una tendencia negativa de la CPUE entre 1994 y 1997. La clasificación por estratos de una flota heterogénea mediante ACP permitió mejorar el análisis de las tasas de captura, aunque la componente espacial debe ser tomada en cuenta en futuros estudios. A su vez, la unidad de esfuerzo de pesca puede tener un impacto notable en las tendencias de CPUE, particularmente si se considera como un índice de abundancia relativaCatch per unit effort (CPUE data from the jack mackerel fishery operating in central-south Chile and covering the period 1987-1999 are analyzed in order to detect changes in relative abundance. Two units for fishing effort were used to compute the catch rate: number of days outside port and the number of trips with capture. The fleet was classified in four