A simple low-cost approach for transport parameter determination in mountain rivers
Castillo, D., Runkel, R.L., Duhalde, D., Pastén, P., Arumí, J.L., Oyarzún, J., Núñez, J., Maturana, H., Oyarzún, R.
A simplified low-cost approach to experimentally determine transport parameters in mountain rivers is described, with an emphasis on the longitudinal dispersion coefficient (DL). The approach is based on a slug injection of table salt (NaCl) as a tracer and specific conductance readings at different locations downstream of the injection spot. Observed specific conductance readings are fit using the advection-dispersion equation with OTIS-P, yielding estimates of cross-sectional area and longitudinal dispersion coefficient for various stream reaches. Estimates of the DL are used to assess the accuracy of several empirical equations reported in the literature. This allowed the determination of complementary transport parameters related to transient storage zones. The empirical equations yielded rather high DL values, with some reaching up an order of magnitude higher to those obtained from tracer additions and OTIS-P. Overall, the proposed approach seems reliable and pertinent for river reaches of ca. 150 m in length.
Referencia APA: Castillo, D., Runkel, R. L., Duhalde, D., Pastén, P., Arumí, J. L., Oyarzún, J., Núñez, J., Maturana, H., & Oyarzún, R. (2021). A simple low-cost approach for transport parameter determination in mountain rivers. River Research and Applications, 1– 9. https://doi.org/10.1002/rra.3890
Environmental Aspects of a Major ARD Source at El Indio Au-Cu-As District, North-Central Chile
Oyarzún, J., Maturana, H., Paulo, A., Lillo, J., Pastén, P., Núñez, J., Duhalde, D., González, C., Portilla, A., & Oyarzún, R
El Indio, an Au-Cu-As deposit with outstanding gold grades, was mined in the Andes of the Coquimbo region, Chile, between 1975 and 2002. Sediment and water sampling of the rivers in the 2000 s found exceptional As and metal levels in modern and old sediments. The studies also revealed that acid rock drainage (ARD) has been present in the district for nearly 10,000 years and the effect that the mining of the district had in terms of geochemical anomalies. The convergence of mineralogical, structural, and hydrologic conditions has generated a metal-rich ARD, a process followed by transference of metals to the fine sediments. In this context, the study also deals with the risk of metal and metalloid transfers from the sediments to the river waters as a consequence of eventual physical-chemical changes, due for example, to climatic-driven conditions. Water and sediment samplings were carried out to provide materials for selective extraction tests under acidic, acid-reducing, and acid-oxidizing conditions. The different behavior of metals and metalloids was revealed and highlighted the refractory character of As. Additionally, the study included the characterization of the sediment’s mineralogy, and allowed the detection of new geochemical anomalies of Cu, Zn, Co, and Y in the Incaguaz River, along with high dissolved Li concentrations in the Toro and Turbio rivers.
Referencia APA: Oyarzún, J., Maturana, H., Paulo, A., Lillo, J., Pastén, P., Núñez, J., Duhalde, D., González, C., Portilla, A., & Oyarzún, R. 2021. Environmental Aspects of a Major ARD Source at El Indio Au-Cu-As District, North-Central Chile. Mine Water Environ. https://doi.org/10.1007/s10230-021-00804-z
Assessment of a conservative mixing model for the evaluation of constituent behavior below river confluences, Elqui River Basin, Chile
Rossi, C., Oyarzún, J., Pastén, P., Runkel, R. L., Núñez, J., Duhalde, D., Maturana, H., Rojas, E., Arumí, J. L., Castillo, D., & Oyarzún, R.
Fate and transport modeling of water-borne contaminants is a data demanding and costly endeavor, requiring considerable expes such, it becomes important to know when a complex modeling approach is required, and when a simpler approach is adequate. This is the main objective herein, where a conservative mixing model is used to characterize the transport of As, Cu, Fe, and SO4. The study area is divided into three sectors, corresponding to the upstream, middle, and downstream portions of the Elqui River Basin, Chile. In Sector 1, acidic conditions result in the conservative transport of constituents that are sourced from acid rock drainage. In Sector 2, pH increases and transport is influenced by pH-dependent reactions and the subsequent settling of the particulate phase. In Sector 3, there are no additional constituent inputs, and the constituents are conservatively transported downstream. Conservative transport within Sector 3 is confirmed through the development of a regression model that provides monthly estimates of SO4 load. Whereas SO4 and Cu concentrations are adequately approximated by the conservative mixing model, estimates of As and Fe concentrations exhibit larger errors, due to the more reactive behavior of these constituents. The fact that the simple, conservative mixing model describes SO4 transport is a valuable result, as this constituent is known to be one of the primary indicators of mining-related contamination in rivers. The approach could also be a useful starting point for further evaluations of the effects of climate change and hydrological variability on the water quality of rivers.
Referencia APA: Rossi, C., Oyarzún, J., Pastén, P., Runkel, R. L., Núñez, J., Duhalde, D., Maturana, H., Rojas, E., Arumí, J. L., Castillo, D., & Oyarzún, R. 2021. Assessment of a conservative mixing model for the evaluation of constituent behavior below river confluences, Elqui River Basin, Chile. River Research and Applications, 1– 12. https://doi.org/10.1002/rra.3823
Mining and Industrial Uses
Duhalde D., Castillo D., Oyarzún R., Oyarzún J., Arumí J.L.
This chapter addresses the relationship between water resources and important economic activities in Chile, particularly mining and the manufacturing industry. This assessment involves aspects related to the importance of these industries in the Chilean economy, their water demand throughout the country, associated environmental impacts and, finally, the challenges faced by these sectors in terms of the sustainable use of water resources. To understand the interactions between the aforementioned economic activities and water, one must first consider the climate heterogeneity of Chile. The north of the country has a desert climate while the south is becoming increasingly rainy. On the other hand, mining activity takes place mainly in the area of the country with the greatest water scarcity, while the manufacturing industry is highly diversified throughout Chile. The direct options available to these sectors for achieving sustainable water management are centered on the use of more and better technologies related to recirculation of process water and the use of seawater.
Palabras claves: Mining, Industry, Water scarcity, Uses, Recirculation, Seawater
Referencia APA: Duhalde D., Castillo D., Oyarzún R., Oyarzún J., Arumí J.L. (2021) Mining and Industrial Uses. In: Fernández B., Gironás J. (eds) Water Resources of Chile. World Water Resources, vol 8. Springer, Cham. https://doi.org/10.1007/978-3-030-56901-3_14
Mathematical modeling and quality parameters of Salicornia fruticosa dried by convective drying
Rodríguez-Ramos, F., Leiva-Portilla, D., Rodríguez-Núñez, K., Pacheco, P., Briones-Labarca, V.
The effect of convective drying at 50, 60 and 70 °C on the drying kinetics and quality parameters of Salicornia fruticosa was investigated. To estimate the equilibrium moisture content a desorption isotherm was performed using five empirical models: Halsey, Caurie, Henderson, Smith and Oswin. The experimental data was also fitted to different drying kinetic models (Logarithmic, Two-Terms, Midilli–Kucuk and Exponential Two-Terms). A numerical simulation using the Finite Volume Method allowed us to describe the evolution of temperature and moisture content distributions during drying. The Henderson model was found to be the most suitable for predicting the equilibrium moisture content of S. fruticosa, with values of Xwe in the drying process of 1.51; 1.54 and 1.36 g water/g d.m for 50, 60 and 70 °C, respectively. A good agreement was found between the numerical and experimental results of temperature and moisture during Salicornia drying. The Midilli–Kucuk model presented the best fitting to the drying curves. The effects of drying on S. fruticosa were significant in two quality parameters. Antioxidant capacity decreased in ca. 45% and lightness (> L*) significantly increased at a drying temperature of 70 °C, compared to the fresh samples. The optimum drying temperature where drying time and nutrients loss was minimum was 70 °C. These results can be used to estimate the best drying conditions for producing dehydrated Salicornia. The use of halophytes as sustainable crops is promising, and the vision of their commercial production must be evaluated and considered, given water scarcity in many areas of the planet.
Palabras claves: Salicornia fruticosa, Hot air drying, Drying kinetics, Mathematical modeling
Referencia APA: Rodríguez-Ramos, F., Leiva-Portilla, D., Rodríguez-Núñez, K., Pacheco, P., Briones-Labarca, V. (2021). Mathematical modeling and quality parameters of Salicornia fruticosa dried by convective drying. J Food Sci Technol 58, 474–483 (2021). https://doi.org/10.1007/s13197-020-04556-6
Assessment of Gene Expression Biomarkers in the Chilean Pencil Catfish, Trichomycterus areolatus, from the Choapa River Basin, Coquimbo Chile
Ali, J.M., Montecinos, A., Schulze, T.T., Allmon, L.G., Kallenbach, A.T., Watson, G.F., Davis, P.H., Snow, D.D., Bertin, A., Gouin, N., Kolok, A.S.
The objective of this study was to describe changes in the gene expression in the Chilean catfish, Trichomycterus areolatus, based on their geographic location within the Choapa River. Genes of choice included those that are biomarkers of exposure to metals, oxidative stress, and endocrine disruption. Male and female T. areolatus were sampled from four sites in Janu-ary 2015 differently impacted by human activities. In males, but not females, hepatic gene expression of heat shock protein (HSP70) and cytochrome P450 1A (CYP1A) were significantly elevated at the site adjacent to the small city of Salamanca, relative to the other sites. In females, hepatic HSP70, the aryl hydrocarbon receptor (AHR), and the estrogen responsive genes, vitellogenin (VTG) and estrogen receptor alpha (ERα), were significantly lower at the site located furthest downstream. A similar downstream pattern of lower expression levels also was found in ovarian tissue for the genes, HSP70 and ERα. Gill gene expression showed a unique pattern in females as levels of metallothionein were elevated at the site furthest downstream. While analytical chemistry of water samples provided limited evidence of agrichemical contamination, the gene expression data are consistent with an exposure to agrichemicals and metals. T. areolatus may be a valuable sentinel organism and its use as a bioindicator species in some rivers within Chile can provide considerable insight, particularly in situations analytical chemistry is limited by environmental constraints.
Referencia APA: Ali, J.M., Montecinos, A., Schulze, T.T., Allmon, L.G., Kallenbach, A.T., Watson, G.F., Davis, P.H., Snow, D.D., Bertin, A., Gouin, N., Kolok, A.S. (2019). Assessment of Gene Expression Biomarkers in the Chilean Pencil Catfish, Trichomycterus areolatus, from the Choapa River Basin, Coquimbo Chile. Archives of Environmental Contamination and Toxicology, 78:137–148. https://doi.org/10.1007/s00244-019-00678-x
Multiple reproductive modes of Myrcianthes coquimbensis (Myrtaceae), an endangered shrub endemic to the Atacama Desert
García-Guzmán, P., Loayza, A., & Squeo, F.
Many plants can produce seeds via multiple reproductive modes, such as selfing and outcrossing. Having multiple reproductive modes can be advantageous if it assures seed production when outcrossing fails, which is important for species inhabiting environments where pollinators are scarce or variable. However, it can also be disadvantageous due to the fitness costs associated to selfing. Consequently, plants have mechanisms to reduce the incidence of selfing. Here we examined the breeding system of Myrcianthes coquimbensis; this threatened Atacama Desert shrub is the last species to bloom in the community and exhibits low visitation rates per flower because pollinators are less abundant. Our aim was to determine whether this plant can produce fruits by modes other than outcrossing, and whether it possesses floral traits to prevent sexual interference. We conducted experimental flower treatments in two localities to determine whether fruits were produced by outcrossing, selfing, autonomous selfing and agamospermy. We also evaluated stigma receptivity and pollen viability during a flower’s lifespan. M. coquimbensis developed fruits and seeds by all the reproductive modes assessed, including selfing and agamospermy. Flowers presented partial segregation of sexual functions, with the peak of pollen viability occurring before the peak of stigma receptivity. Selfing is unavoidable in M. coquimbensis and likely interferes with outcrossing. Coupled with possible early inbreeding depression, it probably results in a cost for seed production. Our results suggest that this species may be vulnerable in scenarios where pollinators are scarce; however, agamospermy may provide an alternative route of seed production in these scenarios.
Palabras claves: Breeding system, Agamospermy, Selfing, Mix-Mating, Protandry, Reproductive assurance, Sexual interference.
Referencia APA: García-Guzmán, P., Loayza, A., & Squeo, F. (2020). Multiple reproductive modes of Myrcianthes coquimbensis (Myrtaceae), an endangered shrub endemic to the Atacama Desert. Flora, 263, 151537. doi: 10.1016/j.flora.2020.151537
Biochemical composition as a function of fruit maturity stage of bell pepper (Capsicum annum) inoculated with Bacillus amyloliquefaciens
Cisternas-Jamet, J., Salvatierra-Martínez, R., Vega-Gálvez, A., Stoll, A., Uribe, E., & Goñi, M.
The use of growth promoting bacteria in sweet pepper plants (Capsicum annuum), such as some Bacillus strains,
has previously been related to increased yields and plant resistance. However, it is also important to evaluate the
effect that inoculation has on the ripening process and on the nutritional composition of the fruits. In the present
work, the effect of root inoculation of sweet pepper plants with Bacillus amyloliquefaciens on the composition of
sweet peppers harvested at different stages of maturation is evaluated. It was possible to determine a clear effect
of inoculation on the fixation of Ca and Fe, and the content of vitamin C and compounds with antioxidant
capacity. Root inoculation with Bacillus amyloliquefaciens generated an increase in the concentration of calcium,
iron and vitamin C of 561 mg kg−1, 182 mg kg−1 and 561 μg 100 g−1 d.m., respectively in Red II and Green I
compared to the control samples. An increase in antioxidant capacity was generated, which is reflected in an
increase in the ORAC test of 1618 umol TE 100 g−1 d.m. and in 587 umol TE 100 g−1 d.m. for Green I and Red I
crops respectively. On the other hand, the effect of the fruit ripening process was significant, especially in
relation to the development of natural pigments and phenolic compounds, with high antioxidant potential. An
increased of extractable pigments of 57 color units with respect to the control sample in Red II is highlighted,
which enhances the organoleptic attractiveness of the fruit. These results would allow producers to determine
the time at which to harvest to maximize the nutritional contribution of sweet peppers.
Palabras claves: Bacillus, Biofertilizer, Nutraceutical, Antioxidants, Vitamin C
Referencia APA: Cisternas-Jamet, J., Salvatierra-Martínez, R., Vega-Gálvez, A., Stoll, A., Uribe, E., & Goñi, M. (2020). Biochemical composition as a function of fruit maturity stage of bell pepper (Capsicum annum) inoculated with Bacillus amyloliquefaciens. Scientia Horticulturae, 263, 109107. doi: 10.1016/j.scienta.2019.109107
Esculturas de acero: observaciones de corrosión e inhibición mediante una cámara de niebla salina, sensores y un microscopio de bajo costo
Novoa Jerez, J., Alfaro Guerra, M., & Alfaro Alcaíno, I.
La presencia de partículas de NaCl en el aerosol marino produce corrosión en esculturas de acero de interés patrimonial, valor artístico y arquitectónico. Es aquí donde la observación de la corrosión utilizando una cámara de neblina, sensores y un microscopio de bajo costo podría permitir su estudio, junto con la ventaja de poder desarrollar proyectos en conjunto entre carreras de Pedagogía en Química con carreras de Pedagogía en Historia y Geografía y Pedagogía en Matemáticas y Computación, además del estudio de las propiedades anticorrosivas de Metamizol frente al acero al carbono sometido al aerosol marino en la cámara de neblina mediante la utilización de fotomicrografías.
Palabras claves: Corrosión atmosférica, Aerosol marino, Esculturas de acero, Cámara de neblina, Sensores, Microscopio de bajo costo.
Referencia APA: Novoa Jerez, J., Alfaro Guerra, M., & Alfaro Alcaíno, I. (2019). Esculturas de acero: observaciones de corrosión e inhibición mediante una cámara de niebla salina, sensores y un microscopio de bajo costo. Retrieved 25 July 2019, from Educación Química (Vol 30, No 2).
Unexpected population fragmentation in an endangered seabird: the case of the Peruvian diving-petrel
Cristofari, R., Plaza, P., Fernández, C., Trucchi, E., Gouin, N., Le Bohec, C., Zavalaga, C., Alfaro-Shigueto, J., Luna-Jorquera, G.
In less than one century, the once-abundant Peruvian diving petrel has become the first endangered seabird of the Humboldt Current System (HCS). This small endemic petrel of the South American Pacific coast is now an important indicator of ongoing habitat loss and of the success of local conservation policies in the HCS - an ecoregion designated as a priority for the conservation of global biodiversity. Yet so far, poorly understood life history traits such as philopatry or dispersal ability may strongly influence the species’ response to ecosystem changes, but also our capacity to assess and interpret this response. To address this question, we explore the range-wide population structure of the Peruvian diving petrel, and show that this small seabird exhibits extreme philopatric behavior at the island level. Mitochondrial DNA sequences and genome-wide SNP data reveal significant isolation and low migration at very short distances, and provide strong evidence for questioning the alleged recovery in the Peruvian and Chilean populations of this species. Importantly, the full demographic independence between colonies makes local population rescue through migration unlikely. As a consequence, the Peruvian diving petrel appears to be particularly vulnerable to ongoing anthropogenic pressure. By excluding immigration as a major factor of demographic recovery, our results highlight the unambiguously positive impact of local conservation measures on breeding populations; yet at the same time they also cast doubt on alleged range-wide positive population trends. Overall, the protection of independent breeding colonies, and not only of the species as a whole, remains a major element in the conservation strategy for endemic seabirds. Finally, we underline the importance of considering the philopatric behavior and demographic independence of breeding populations, even at very fine spatial scales, in spatial planning for marine coastal areas.
Referencia APA: Cristofari, R., Plaza, P., Fernández, C., Trucchi, E., Gouin, N., Le Bohec, C., Zavalaga, C., Alfaro-Shigueto, J., Luna-Jorquera, G. (2019). Unexpected population fragmentation in an endangered seabird: the case of the Peruvian diving-petrel. Scientific Reports, 9(1). doi: 10.1038/s41598-019-38682-9
Effect of high hydrostatic pressure treatment on physical parameters, ultrastructure and shelf life of pre- and post-rigor mortis palm ruff (Seriolella violacea) under chilled storage
Roco, T., Torres, M., Briones-Labarca, V., Reyes, J., Tabilo-Munizaga, G., & Stucken, K., Lemus-Mondaca, R., Pérez-Won, M.
To identify processing conditions that better maintain palm ruff quality attributes, high hydrostatic pressure (HHP) was applied to pre- and post-rigor fillets. Physical parameters as whiteness index (WI), water holding capacity (WHC), texture and ultrastructure and shelf life were evaluated after the application of 450 and 550 MPa (3 and 4 min) and during cold storage. Pre-rigor fillets retained less water and were softer than post-rigor, although the onset of rigor increased palm ruff's WHC and firmness. Application of HHP whitened palm ruff's dark flesh; however, this effect reverted at the end of the storage. Pressurized post-rigor samples retained less water than the control and storage caused a WHC increase in samples pressurized at 550 MPa, independent on the rigor condition. Post-rigor fillets softened at pressures of 450–550 MPa appearing to have a lower threshold than beef or cod (above 600 MPa). Ultrastructural changes revealed a subtle contraction (7.4%) of the myofibrils in the unpressurized post-rigor muscle compared to pre-rigor; after 26 days' storage both samples presented extensive muscle degradation and sarcomere length was reduced in 30%. HHP induced pressure-dependent shortening of the sarcomere and modifications to the structure which after 550 MPa was hardly recognizable. After 26 days' storage, there was only slight degradation of the ultrastructure, showing that beyond the structural modifications caused by HHP, post-mortem deterioration is delayed in HHP-treated fillets. Furthermore, HHP extended palm ruff's shelf life to 14–23 days. Thus, HHP may be considered as a technology that maintains the textural quality and shelf life of fresh and stored fish.
Palabras claves: Palm ruff, Rigor mortis, High hydrostatic pressure, Shelf life, StorageTexture, Ultrastructure
Referencia APA: Roco, T., Torres, M., Briones-Labarca, V., Reyes, J., Tabilo-Munizaga, G., & Stucken, K., Lemus-Mondaca, R., Pérez-Won, M. (2018). Effect of high hydrostatic pressure treatment on physical parameters, ultrastructure and shelf life of pre- and post-rigor mortis palm ruff (Seriolella violacea) under chilled storage. Food Research International, 108, 192-202. doi: 10.1016/j.foodres.2018.03.009
Optimization of extraction yield, flavonoids and lycopene from tomato pulp by high hydrostatic pressure-assisted extraction
Briones-Labarca, V., Giovagnoli-Vicuña, C., & Cañas-Sarazúa, R.
Tomato pulp is a useful source of antioxidants, which can be extracted by high hydrostatic pressure (HHPE). This study aimed to optimize the individual and interactive effect of operating high pressure and solvent polarity (solvent mixture) on yield extraction, flavonoid and lycopene content from tomato pulp (Solanum lycopersicum) by using response surface methodology (RSM). The results showed that the selected factors (high pressure and solvent mixture) have a significant influence on extraction yield, flavonoid and lycopene content. Extraction at 450 MPa and 60% hexane concentration in the solvent mixture was considered the optimal HHPE condition since it provided the maximum extraction yield (8.71%), flavonoid (21.52 ± 0.09 mg QE/g FW) and lycopene content (2.01 ± 0.09 mg QE/100 g FW). Therefore, HHPE could be a useful tool improve the extraction and release of potentially health-related compounds while providing information on the cumulative effect of solvent polarity and high-pressure extraction on antioxidant compounds of fruits.
Palabras claves: Tomato, High hydrostatic pressure, Antioxidant capacity, Response surface methodology
Referencia APA: Briones-Labarca, V., Giovagnoli-Vicuña, C., & Cañas-Sarazúa, R. (2018). Optimization of extraction yield, flavonoids and lycopene from tomato pulp by high hydrostatic pressure-assisted extraction. Food Chemistry, 278, 751-759. doi: 10.1016/j.foodchem.2018.11.106