CEAZA
A kinetic approach to saponin extraction during washing of quinoa ( Chenopodium Quinoa Willd.) seeds.
Quispe-Fuentes, I., Vega-Gálvez, A., Miranda, M., Lemus-Mondaca, R., Lozano, M., & Ah-Hen, K.
The aim of this work was to show that the leaching process of saponins from quinoa (Chenopodium quinoa Willd.) seeds during washing with water, as is generally practiced by people in South America, can be modeled using mathematical expressions related to Fick's second law. Experimental data were obtained through batch extraction with a ratio of quinoa to water of 1:10 under constant agitation for processing time between 15 and 120 min at 20, 30, 40, 50 and 60C. It was found that residual saponin concentration in the quinoa seeds decreased as washing temperature increased. Leaching rate followed the Arrhenius relationship, with calculated effective saponin diffusion coefficient between (5.05 ± 0.15) × 10−10 and (32.50 ± 1.65) × 10−10 m2/s as the temperature increased from 20 to 60C. Several mathematical models to describe the kinetic behavior of the leaching process were analyzed. The modified Henderson–Pabis model had the best fit quality as shown by statistical analysis.
Año: 2013
Palabras claves:
Referencia APA: Quispe-Fuentes, I., Vega-Gálvez, A., Miranda, M., Lemus-Mondaca, R., Lozano, M., & Ah-Hen, K. (2013). A kinetic approach to saponin extraction during washing of quinoa ( Chenopodium Quinoa Willd.) seeds. Journal Of Food Process Engineering, 36(2), 202-210.
Seasonal sediment fluxes forcing supraglacial melting on the Wright Lower Glacier, McMurdo Dry Valleys, Antarctica.
MacDonell, S., Fitzsimons, S., & Mölg, T.
Cold-based glaciers exist in low temperature and low humidity environments in which shortwave radiation is the largest source of energy to the glacier surface and the energy budget is very sensitive to the surface albedo. Consequently, the presence of relatively low volumes of debris on glacier surfaces has a significant impact on the timing, magnitude and rate of ablation at the surface. The aim of this study is to understand how the presence of sediment on the glacier surface at the start of the melt season can affect meltwater generation and delivery on a cold-based glacier. A combination of field measurements, energy balance modelling and chemical mixing modelling were used on the Wright Lower Glacier, McMurdo Dry Valleys, Antarctica, between October 2005 and January 2006 to address this aim. In this system, sediment was transported onto the glacier surface during the winter months (March–October) by foehn winds, which reduced surface albedo at the start of the summer melt season. The areas of the glacier on which sediment accumulated began to melt earlier than other parts of the glacier and experienced a longer melt season. Over the study period, the total ablation on the dirty surfaces was nine times greater than for clean ice. Ablation on the dirty surfaces is dominated by melting, whereas sublimation dominates the clean ice. As the sediment was unevenly distributed over the glacier surface, the variation in melt amount and timing drove the development of a cryoconite hole system. Copyright © 2012 John Wiley & Sons, Ltd.
Año: 2013
Palabras claves: Glacier hydrology; cryoconite hole; glacier energy balance; hydrochemistry.
Referencia APA: MacDonell, S., Fitzsimons, S., & Mölg, T. (2013). Seasonal sediment fluxes forcing supraglacial melting on the Wright Lower Glacier, McMurdo Dry Valleys, Antarctica. Hydrol. Process., n/a-n/a.
Trends in Antarctic ecological research in Latin America shown by publications in international journals.
Stotz, G., Salgado-Luarte, C., Rios, R., Acuña-Rodriguez, I., Carrasco-Urra, F., Molina-Montenegro, M., & Gianoli, E.
Antarctica is a highly interesting region for ecologists because of its extreme climatic conditions and the uniqueness of its species. In this article, we describe the trends in Antarctic ecological research participation by Latin American countries. In a survey of articles indexed by the ISI Web of Science, we searched under the categories “Ecology,” “Biodiversity Conservation” and “Evolutionary Biology” and found a total of 254 research articles published by Latin American countries. We classified these articles according to the country of affiliation, kingdom of the study species, level of biological organization and environment. Our main finding is that there is a steady increase in the relative contribution of Latin American countries to Antarctic ecological research. Within each category, we found that marine studies are more common than terrestrial studies. Between the different kingdoms, most studies focus on animals and most studies use a community approach. The leading countries in terms of productivity were Argentina, Chile and Brazil, with Argentina showing the highest rate of increase.
Año: 2013
Palabras claves: Antarctica; Argentina; Brazil; Chile; research trends; scientific productivity.
Referencia APA: Stotz, G., Salgado-Luarte, C., Rios, R., Acuña-Rodriguez, I., Carrasco-Urra, F., Molina-Montenegro, M., & Gianoli, E. (2013). Trends in Antarctic ecological research in Latin America shown by publications in international journals. Polar Research, 32(0).
Influence of contrasting environments on seed composition of two quinoa genotypes: nutritional and functional properties.
Miranda, M., Vega-Gálvez, A., Martínez, E., López, J., Marín, R., Aranda, M., & Fuentes, F.
Quinoa (Chenopodium quinoa Willd.) in Chile represents a source of germplasm with high nutritional value. However, there is little information available related to quinoa seed quality grown under contrasting environments. In this study we evaluated the changes on seed composition of seeds of two lowland/coastal quinoa genotypes grown under arid (Vicuna) and cold-temperate (Temuco) conditions in Chile. Results showed that in the case of 'Regalona Baer' and 'Villarrica' genotypes the arid location (with irrigation) led to a significant increase (P < 0.05) in grain yield (4.2 and 5.1 t ha-1, respectively), soluble dietary fiber (16.8 ± 0.4 and 28.9 ± 2.1 g kg-1 DM, respectively), vitamin B3 (2.44 ± 0.005 and 2.26 ± 0.04 mg 100 g-1 DM, respectively), saponins (3.22 ± 0.38 mg 100 g-1 DM, 'Regalona Baer'), phenolic compounds (19.2 ± 5.48 and 31.92 ± 1.14 mg gallic acid 100 g-1 DM, respectively) and components of proximate analysis, except protein content. The cold-temperate climate (rainfed) affected positively seed size (2.22 ± 0.17 mm 'Villarrica') and 1000 seed weight (3.08 ± 0.08 and 3.29 ± 0.08 g, respectively), as well as insoluble dietary fiber content (112.3 ± 23.8 g kg-1 DM, 'Regalona Baer'). Furthermore, vitamin C was higher in 'Regalona Baer' genotype at arid locality (31.22 ± 4.2 mg 100 g-1 DM), but much higher content was registered in 'Villarrica' genotype at cold-temperate climate (49.3 ± 5.36 mg 100 g-1 DM). The environment-induced relationship among variables and genotypes was consistent with principal component analysis (PCA). The arid region of Vicuna in Chile represents a potential area for quinoa cultivation for lowland/coastal quinoa genotypes, whose nutritional and functional features were affected positively, due to the much more stressing climatic conditions.
Año: 2013
Palabras claves: Chenopodium quinoa, climate stress, antioxidant activity, phenolic compounds, protein, mineral content.
Referencia APA: Miranda, M., Vega-Gálvez, A., Martínez, E., López, J., Marín, R., Aranda, M., & Fuentes, F. (2013). Influence of contrasting environments on seed composition of two quinoa genotypes: nutritional and functional properties. Chilean J. Agric. Res., 73(2), 06-07.
Mesoscale Variation of Mechanisms Contributing to Stability in Rocky Shore Communities.
Valdivia N, González AE, Manzur T, Broitman BR.
Environmental fluctuations can generate asynchronous species’ fluctuations and community stability, due to compensatory dynamics of species with different environmental tolerances. We tested this hypothesis in intertidal hard-bottom communities of north-central Chile, where a persistent upwelling centre maintains a mosaic in sea surface temperatures (SST) over 10s of kilometres along the shore. Coastal upwelling implies colder and temporally more stable SST relative to downstream sites. Uni- and multivariate analyses of multiyear timeseries of SST and species abundances showed more asynchronous fluctuations and higher stability in sites characterised by warmer and more variable SST. Nevertheless, these effects were weakened after including data obtained in sites affected by less persistent upwelling centres. Further, dominant species were more stable in sites exposed to high SST variability. The strength of other processes that can influence community stability, chiefly statistical averaging and overyielding, did not vary significantly between SST regimes. Our results provide observational evidence supporting the idea that exogenously driven compensatory dynamics and the stabilising effects of dominant species can determine the stability of ecosystems facing environmental fluctuations.
Año: 2013
Palabras claves: Community ecology, Algae, Barnacles, Ecosystems, Oceanography, Surface temperature, Taxonomy, Species interactions.
Referencia APA: Valdivia N, González AE, Manzur T, Broitman B. (2013). Mesoscale Variation of Mechanisms Contributing to Stability in Rocky Shore Communities. PLoS ONE 8(1): e54159.
Seabirds modify El Niño effects on tree growth in a southern Pacific island.
Molina-Montenegro, M., Torres-Díaz, C., Gallardo-Cerda, J., Leppe, M., & Gianoli, E.
Oceanic island ecosystems are particularly sensitive to El Niño effects due to their dependence on energy and nutrient inputs from marine systems. Seabirds play a key role in transporting resources of marine origin to insular ecosystems. We report tree-growth patterns showing how the effects of El Niño rainy events on tree species in a southern Pacific island depend on the presence of local seabird colonies. We performed manipulative experiments in order to assess the mechanisms underlying these patterns. Tree ring data showed that, in normal years, the growth of all tree species (Aextoxicon punctatum, Cryptocarya alba, and Pinus radiata) was significantly lower in seabird sites compared to adjacent patches without seabirds (control sites). In contrast, in El Niño years, trees formerly hosting seabird colonies grew more than those in control sites. Experiments showed that (1) pine plants on soil from seabird sites grew more than those on soil from control sites, (2) pine individuals with seabird feces on their leaves grew less than those sprayed with an aqueous solution, and (3) soil moisture had little effect on plant growth. The stress produced by massive cormorant nesting on trees, which impairs tree growth and physiological performance, is relieved during El Niño events because of seabird migration due to decreased prey availability and pouring rains that flood nests. Soils enriched by the seabird guano, together with the increased water availability associated with El Niño, foster the growth of trees from seabird sites. We suggest that El Niño may be a key determinant of tree performance in forest communities from island and coastal ecosystems of the Pacific Ocean.
Año: 2013
Palabras claves: Aextoxicon punctatum; colonial seabirds; Cryptocarya alba; ecophysiology; El Niño Southern Oscillation, ENSO; global change; island system interactions; Neotropic Cormorant, Phalacrocorax brasilianus; Pinus radiata; Quiriquina Island, Chilean coast; tree rings.
Referencia APA: Molina-Montenegro, M., Torres-Díaz, C., Gallardo-Cerda, J., Leppe, M., & Gianoli, E. (2013). Seabirds modify El Niño effects on tree growth in a southern Pacific island. Ecology, 94(11), 2415-2425.
Variabilidad ambiental y recursos pesqueros en el Pacifico suroriental: estado de la investigacion y desafios para el manejo pesquero.
Parada, C., Yannicelli, B., Hormazabal, S., Vasquez, S., Porobic, J., & Ernst, B. et al.
Las fluctuaciones en abundancia, biomasa, estructura de edad y patrones de distribución de los recursos pesqueros responden, entre otros, a la variabilidad ambiental. Estas respuestas son consecuencia tanto de efectos climáticos directos sobre los recursos como indirectos actuando sobre niveles tróficos relacionados. En este estudio se revisa: i) el estado del conocimiento de los mecanismos físicos asociados a la variabilidad océano-atmósfera y las escalas de variabilidad espaciales y temporales del ambiente y la relación con recursos marinos, basados en datos observacionales y modelos hidrodinámicos, ii) la relación ambiente-recurso para pesquerías pelágicas, demersales y bentónicas, y el uso de modelos biofísicos para entender estas relaciones, iii) manejo actual de recursos pelágicos, demersales y bentónicos y los alcances en relación al uso de variables ambientales, y iv) se discuten los desafíos hacia la asesoría en relación a las estrategias para mejorar la comprensión de la relación ambiente-recurso, así como, las estrategias para incorporar la modelación biofísica y variables ambientales en modelos operacionales para la asesoría hacia el manejo.
Año: 2013
Palabras claves: Variabilidad ambiental, sistemas de surgencia, recursos pesqueros, modelación biofísica, dinámica poblacional, modelos operacionales para el manejo pesquero, Pacífico suroriental, Chile.
Referencia APA: Parada, C., Yannicelli, B., Hormazabal, S., Vasquez, S., Porobic, J., & Ernst, B. et al. (2013). Variabilidad ambiental y recursos pesqueros en el Pacifico suroriental: estado de la investigacion y desafios para el manejo pesquero. Latin American Journal Of Aquatic Research, 41(1), 1-28.
Can a breakdown in competition-colonization tradeoffs help explain the success of exotic species in the California flora?
Molina-Montenegro, M., Cleland, E., Watts, S., & Broitman, B.
Determining combinations of functional traits that allow a species to colonize new habitats has been central in the development of invasion ecology. Species able to establish in new communities harbor abilities or traits that allow them to use resources or tolerate stress in ways that native species cannot. Tradeoffs among species functional traits along the competition–colonization (CC) continuum, where competitive ability is a decreasing function of dispersal capacity, may allow invasive species to establish themselves in new habitats. The California flora offers a well-characterized model system to examine whether native and exotic species differ in the distribution of functional traits and to examine whether a breakdown of the CC tradeoff is present. We used a random subset of 1000 plants and examined seed traits and life form characteristics along with their seed size and adult height using the Jepson Manual of the plants of California. To test the hypothesis that active dispersal strategies aid in the success of exotic species, we classified species into four seed types according to the presence/absence of mechanisms associated with efficient dispersal. In addition, for each species we compiled data on seed size and adult plant height. We conducted all comparisons between native and exotic species within the four most speciose families to control for potential taxonomic non-independence. Exotic species had smaller seed size but greater plant height than natives of the same families. On the other hand, exotic species also displayed significantly greater proportions of functional traits that enhanced dispersal ability. Additionally, certain sets of functional traits were significantly associated with exotic species, such as annual life histories with small seeds and high dispersal capacity. In the random subset of the California flora examined, exotics of the most speciose plant families show functional trait combinations that appear to violate the tradeoff structures observed in their California counterparts. Our results suggest that taxonomically controlled comparisons of the CC tradeoff structure between natives and exotic species may shed light of the capacity of those exotic species invasive ability to colonize new habitats.
Año: 2012
Palabras claves:
Referencia APA: Molina-Montenegro, M., Cleland, E., Watts, S., & Broitman, B. (2012). Can a breakdown in competition-colonization tradeoffs help explain the success of exotic species in the California flora?. Oikos, 121(3), 389-395.
Characterization of the interactions between subterranean and superficial fluxes within an Andean catchment as a function of the spatio- temporal variability of climate.
Jourde, H., Blanc, M., Rochette, R., Ruelland, D., Hicks, E., & Oyarzun, R
In the semi-arid region of Norte Chico (Chile), climate variability, mainly controlled by ENSO and LNSO events, generates a high variability of both surface water and groundwater fluxes. Taking the upper Elqui catchment as an example, this study found that, during LNSO events, the abnormally high values of the runoff coefficient may be the consequence of a groundwater contribution to surface water flow. During ENSO events, however, the lower values of the runoff coefficient and the dynamics of the water table level highlight the recharge of the subsurface compartment. For the hydrological years characterized by a high pluviometric index during the 1977–2008 period, three dynamics of interaction between groundwater and surface water are identified : (i) the water table increases before the river discharge, and its logarithmic increase highlights a rapid recharge related to the concomitance of snowmelt and rainfall events ; (ii) the water table increases after the river discharge and its exponential increase shows a progressive intensification of the recharge over time ; and (iii) the water table and the river discharge increase are concomitant. Dynamics (i) and (ii) are observed during the ENSO events, when precipitation occurs over a long time period ; dynamic (iii) is observed during the neutral years, when high intensity precipitations occur over short periods. The analysis of these dynamics and runoff coefficients shows that when the mean annual precipitation is less than 70 mm, the relative equilibrium between runoff and recharge processes is broken, which may generate a high hydrological deficit; this threshold could thus be used as a warning for drought. Finally, the spatial variability of runoff coefficients shows a larger contribution of the subsurface compartment in catchment with a larger proportion of granites, suggesting a mountain front recharge from the alterites in the granitic watershed.
Año: 2012
Palabras claves: hydro-climatic variability, water resource, surface, subsurface interactions, snowmelt, Río Elqui, North-Central Chile.
Referencia APA: Jourde, H., Blanc, M., Rochette, R., Ruelland, D., Hicks, E., & Oyarzun, R. (2012). Caractérisation des interactions entre flux souterrains et superficiels dans un bassin andin en fonction de la variabilité spatio-temporelle du climat. La Houille Blanche, (2), 18-25
Activity patterns and predatory behavior of an intertidal nemertean from rocky shores: Prosorhochmus nelsoni (Hoplonemertea) from the Southeast Pacific.
Caplins, S., Penna-Diaz, M., Godoy, E., Valdivia, N., Turbeville, J., & Thiel, M.
Understanding the impact of environmental stressors on predator activity is a prerequisite to understanding the underlying mechanisms shaping community structure. The nemertean Prosorhochmus nelsoni is a common predator in the mid-intertidal zone on rocky shores along the Chilean coast, where it can reach very high abundances (up to 260 ind m−2) in algal turfs, algal crusts, barnacle crusts, and mixed substrata. Tidal and diurnal scans revealed that the activity of P. nelsoni is primarily restricted to night and early-morning low tides and is relatively low when air temperatures are high. On average, larger worms crawled faster than smaller worms, with their maximum velocity being influenced by substratum type. Their estimated rate of predation is 0.092 prey items nemertean−1 day−1, just below the laboratory rate of ~0.2 amphipods nemertean−1 day−1 previously estimated for this species. P. nelsoni consumes a diverse spectrum of prey items (i.e., amphipods, isopods, decapods, barnacles, and dipterans) and is possibly exerting a significant influence on its prey populations. We suggest that the opportunistic predatory behavior of this intertidal predator is caused by the trade-off between immediate persistence (e.g., avoidance of desiccation) and long-term survival through successful foraging.
Año: 2012
Palabras claves:
Referencia APA: Caplins, S., Penna-Diaz, M., Godoy, E., Valdivia, N., Turbeville, J., & Thiel, M. (2012). Activity patterns and predatory behavior of an intertidal nemertean from rocky shores: Prosorhochmus nelsoni (Hoplonemertea) from the Southeast Pacific. Marine Biology, 159(6), 1363-1374.
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