CEAZA
Abandoned tailings deposits, acid drainage and alluvial sediments geochemistry, in the arid Elqui River Basin, North-Central Chile. Journal of Geochemical Exploration
Oyarzún J, Castillo D, Maturana H, Kretschmer N, Soto G, Amezagad JM, Röttingd TS, Youngere PL, Oyarzún R
Two major pollutant sources related to hydrothermal ore deposits and mining operations exist in the Elqui river basin, Chile: (a) acid drainage from Andean epithermal El Indio Au–Ag–Cu–As district and nearby hydrothermal alteration zones, and (b) diffuse sediment dispersion from abandoned tailings deposits in usually dry creeks in the western belt of the basin. This work analyses the contribution of both sources to the current metal contents of the fine grained sediments of the rivers and creeks of the Elqui basin, including a group of chemical elements and data analysis techniques not considered in previous works carried out in the area. Analysis of “active sediments” (i.e., sediments in permanent contact with surface water) in the main channel and tributaries of the Elqui river reveals that both pollutant sources contribute to their exceptionally high Cu contents (between 0.1 and 0.2% in the minus 60 mesh fraction). However, As pollution (0.03%) is mainly derived from the El Indio district. Potentially toxic heavy metals (notably Cd, Pb, Hg and Mo) are present in low concentrations and do not represent major threats to ecology or human health. Nevertheless, ongoing erosion of abandoned tailings deposits may result in soil contamination and thus be detrimental to the export-oriented agriculture of the Elqui basin. Consequently, remediation of that source should be prioritized.
Año: 2012
Palabras claves: Acid drainage; Active sediments; Hydrothermal alteration; Tailings; CAMINAR
Referencia APA: Oyarzún J, Castillo D, Maturana H et al. (2012). Abandoned tailings deposits, acid drainage and alluvial sediments geochemistry, in the arid Elqui River Basin, North-Central Chile. Journal of Geochemical Exploration. 2012;115:47-58.
Characterization of genetic markers linked to sex determination in the haploid-diploid red alga gracilaria chilensis1.
Guillemin, M., Huanel, O., & Martínez, E.
Bulk segregant analysis, random amplified polymorphic DNA (RAPD), and sequence characterized amplified region (SCAR) methods were used to identify sex-linked molecular markers in the haploid-diploid rhodophyte Gracilaria chilensis C. J. Bird, McLachlan et E. C. Oliveira. One hundred and eighty 10 bp primers were tested on three bulks of DNA: haploid males, haploid females, and diploid tetrasporophytes. Three RAPD primers (OPD15, OPG16, and OPN20) produced male-specific bands; and one RAPD primer (OPD12), a female-specific band. The sequences of the cloned putative sex-specific PCR fragments were used to design specific primers for the female marker SCAR-D12-386 and the male marker SCAR-G16-486. Both SCAR markers gave unequivocal band patterns that allowed sex and phase to be determined in G. chilensis. Thus, all the females presented only the female band, and all the males only the male band, while all the tetrasporophytes amplified both male and female bands. Despite this sex-specific association, we were able to amplify SCAR-D12-386 and SCAR-G16-486 in both sexes at low melting temperature. The differences between male and female sequences were of 8%–9% nucleotide divergence for SCAR-D12-386 and SCAR-G16-486, respectively. SCAR-D12-386 and SCAR-G16-486 could represent degenerated or diverged sequences located in the nonrecombining region of incipient sex chromosomes or heteromorphic sex chromosomes with sequence differences at the DNA level such that PCR primers amplify only one allele and not the other in highly specific PCR conditions. Seven gametic progenies composed of 19 males, 19 females, and the seven parental tetrasporophytes were analyzed. In all of them, the two SCAR markers segregated perfectly with sexual phenotypes.
Año: 2012
Palabras claves: cultivated red alga; Gracilaria chilensis; random amplified polymorphic DNA; sequence characterized amplified region; sex-linked markers
Referencia APA: Guillemin, M., Huanel, O., & Martínez, E. (2012). Characterization of genetic markers linked to sex determination in the haploid-diploid red alga gracilaria chilensis1. Journal Of Phycology, 48(2), 365-372
Mid-Holocene mean climate in the south eastern Pacific and its influence on South America.
Carré, M., Azzoug, M., Bentaleb, I., Chase, B., Fontugne, M., & Jackson, D., Ledru, M.P., Maldonado, A., et al
The eastern tropical Pacific plays a key role in the tropical atmospheric circulation and in the global carbon cycle, and assessing the sensitivity of this region to global climate changes is a major challenge facing climatologists. Provided here is a synthesis of proxy records of the mean climate of the mid-Holocene (5–8 ka) along the south eastern Pacific margin and four regions of South America. These regions were selected for the strength and stability of ENSO teleconnections, and located outside the direct influence of the intertropical convergence zone or the southern westerlies in order to avoid the overprinting signal of their insolation-related variations and focus on the relationship between the eastern tropical Pacific and South America. This study is based on a review of published multiproxy data as well as new isotopic data from the Peruvian and Chilean coast. The available evidence indicates that sea-surface temperatures were ∼1–4 °C cooler from the Galapagos to the southern Peruvian coast as a result of increased coastal upwelling forced by changes in longshore windfields. The mean La Niña-like conditions in the eastern South Pacific were associated to aridity in southern Brazil and along the whole South American Pacific coast from central Chile to the Galapagos, and to wetter conditions on the western central Andes. This regional synthesis provides a coherent picture of the South American mean climate that is very similar to the modern precipitation pattern observed during La Niña conditions, suggesting that atmospheric teleconnections linking the South Eastern Pacific to these continental areas were similar in the middle Holocene.
Año: 2012
Palabras claves:
Referencia APA: Carré, M., Azzoug, M., Bentaleb, I., Chase, B., Fontugne, M., & Jackson, D., Ledru, M.P., Maldonado, A et al. (2012). Mid-Holocene mean climate in the south eastern Pacific and its influence on South America. Quaternary International, 253, 55-66.
Genetic diversity and comparison of physicochemical and nutritional characteristics of six quinoa (Chenopodium quinoa willd.) genotypes cultivated in Chile.
Miranda, M., Vega-Gálvez, A., Martinez, E., López, J., Rodríguez, M., Henríquez, K., & Fuentes, F.
The present study was focused on the analysis of agronomical, nutritional, physicochemical, and antioxidant properties of six genetically different quinoa (Chenopodium quinoa Willd) genotypes cultivated in three distinctive geographical zones of Chile. Ancovinto and Cancosa genotypes from the northern Altiplano (19 ºS), Cáhuil and Faro from the central region (34 ºS), and Regalona and Villarica from the southern region (39 ºS) are representative of high genetic differentiation among the pooled samples, in particular between Altiplano and the central-southern groups. A Common-Garden Assay at 30 ºS showed significant differences among seed origins in all morphometric parameters and also in yields. Altiplano genotypes had larger panicule length but no seed production. A significant influence of the different quinoa genotypes on chemical composition and functional properties was also observed. Protein concentration ranged from 11.13 to 16.18 g.100 g–1 d.m., while total dietary fiber content ranged from 8.07-12.08 g.100 g–1 d.m., and both were the highest in Villarrica ecotype. An adequate balance of essential amino acids was also observed. Sucrose was the predominant sugar in all genotypes. Antioxidant activity was high in all genotypes, and it was highest in Faro genotype (79.58% inhibition).
Año: 2012
Palabras claves: quinoa; antioxidant activity; amino acids; functional properties.
Referencia APA: Miranda, M., Vega-Gálvez, A., Martinez, E., López, J., Rodríguez, M., Henríquez, K., & Fuentes, F. (2012). Genetic diversity and comparison of physicochemical and nutritional characteristics of six quinoa (Chenopodium quinoa willd.) genotypes cultivated in Chile. Food Science And Technology (Campinas), 32(4), 835-843.
What do we know about high-altitude precipitation in the semi-arid Andes of Chile?
Bourgin P, Andreassian V, Gascoin S, Valery A.
Mapping precipitations on a regular grid is often required for hydrological and ecological modelling. The spatial interpolation methods are generally used to estimate such a distribution from ground-based measurements. In the case of mountainous areas, the estimation of precipitation amounts is still a challenging task and the results of spatial interpolation should be verified as much as possible. Here we describe a three-steps method for the validation of a precipitation map. This is used in the context of a mountainous semi-arid region, the Norte Chico in Chile (26°S-32°S). The implementation of this validation method showed the benefits of an interpolation method developed by Valéry [2010] for mountainous areas. The hydrological balance of the high-altitude watersheds is now more realistic.
Año: 2012
Palabras claves: Precipitation, spatial interpolation method, extrapolation, altitude, altitudinal corrections, validation, water equivalent, water balance.
Referencia APA: Bourgin P, Andreassian V, Gascoin S, Valery A. (2012). Que sait-on des précipitations en altitude dans les Andes semi-arides du Chili?. La Houille Blanche. 2012;(2):12-17.