CEAZA
Glacier meltwater flow paths and storage in a geomorphologically complex glacial foreland: The case of the Tapado glacier, dry Andes of Chile (30°S).
Pourrier, J., Jourde, H., Kinnard, C., Gascoin, S., & Monnier, S.
The Tapado catchment is located in the upper Elqui river basin (4000–5550 m) in northern Chile. It comprises the Tapado glacial complex, which is an assemblage of the Tapado glacier and the glacial foreland (debris-covered glacier, rock glacier, and moraines). Although the hydrological functioning of this catchment is poorly known, it is assumed to actively supply water to the lower semi-arid areas of the Elqui river basin. To improve our knowledge of the interactions and water transfers between the cryospheric compartment (glacier, debris-covered glacier, and rock glacier) and the hydrological compartment (aquifers, streams), the results of monitoring of meteorological conditions, as well as discharge, conductivity and temperature of streams and springs located in the Tapado catchment were analyzed. The hydrological results are compared to results inferred from a ground penetrating radar (GPR) survey of the underground structure of the glacial foreland. Water production from the Tapado glacier was shown to be highly correlated with daily and monthly weather conditions, particularly solar radiation and temperature. The resulting daily and monthly streamflow cycles were buffered by the glacial foreland, where underground transfers took place through complex flow paths. However, the development of a thermokarst drainage network in a portion of the glacial foreland enabled rapid concentrated water transfers that reduced the buffer effect. The glacial foreland was shown to act as a reservoir, storing water during high melt periods and supplying water to downstream compartments during low melt periods. GPR observations revealed the heterogeneity of the internal structure of the glacial foreland, which is composed of a mixture of ice and rock debris mixture, with variable spatial ice content, including massive ice lenses. This heterogeneity may explain the abovementioned hydrological behaviors. Finally, calculation of a partial hydrological budget confirmed the importance of the Tapado catchment in supplying water to lower areas of the Elqui river basin. Water production from, and transfer through, cryospheric compartments, and its subsequent interactions with hydrological compartments are key processes driving the summer water supply from the Tapado catchment.
Año: 2014
Palabras claves: Cryosphere hydrology; Debris-covered glacier; Rock glacier; Thermokarst; Water transfers; Semiarid Andes.
Referencia APA: Pourrier, J., Jourde, H., Kinnard, C., Gascoin, S., & Monnier, S. (2014). Glacier meltwater flow paths and storage in a geomorphologically complex glacial foreland: The case of the Tapado glacier, dry Andes of Chile (30°S). Journal Of Hydrology, 519, 1068-1083.
Rise and fall in diversity of Neogene marine vertebrates on the temperate Pacific coast of South America.
Villafaña, J. & Rivadeneira, M.
Año: 2014
Palabras claves:
Referencia APA: Villafaña, J. & Rivadeneira, M. (2014). Rise and fall in diversity of Neogene marine vertebrates on the temperate Pacific coast of South America. Paleobiology, 40(04), 659-674. http://dx.doi.org/10.1666/13069
Diversity of Quinoa in a Biogeographical Island: a Review of Constraints and Potential from Arid to Temperate Regions of Chile.
Bazile, D., Martínez, E., & Fuentes, F.
Chile, isolated by a hyper-arid desert in the north, the Andes Range to the east and the Pacific and Antarctic waters (west and south), has a highly endemic flora. This hotspot of biodiversity is in danger not only due to increasing desertification, but also because human activities can diminish agrobiodiversity. Quinoa (Chenopodium quinoa Willd.) is an Andean species producing highly nutritious grains, which almost disappeared from Chile during the Spanish colonization. Today less than 300 small-scale and highly isolated farmers still grow it as a rain-fed crop. This review describes the biogeographical-social context of quinoa in Chile, and its high genetic diversity as a product of a long domestication process, resulting in numerous local landraces whose conservation and use for breeding improved varieties is of paramount importance. We suggest the term “lighthouse crop” to emphasize its contribution to small scale ecological and bio diverse agriculture, particularly in stressful environments, to promote a healthier nutrition and more equitable markets in the world. Furthermore this crop and its exceptional nutritional properties were invoked by the United Nations Food and Agriculture Organization (FAO) to promote its use worldwide, and to declare 2013 the International Year of Quinoa.
Año: 2014
Palabras claves: Agrobiodiversity, agroecosystems, Chenopodium quinoa, conservation, cropping systems, lighthouse crop.
Referencia APA: Bazile, D., Martínez, E., & Fuentes, F. (2014). Diversity of Quinoa in a Biogeographical Island: a Review of Constraints and Potential from Arid to Temperate Regions of Chile. Not Bot Hort Agrobot Cluj, 42(2).
Multi-method assessment of connectivity between surface water and shallow groundwater: the case of Limarí River basin, north-central Chile.
Oyarzún, R., Barrera, F., Salazar, P., Maturana, H., Oyarzún, J., & Aguirre, E. et al.
A study that tests the applicability and consistency of independent but complementary approaches in the assessment of interactions between surface water and shallow groundwater within a water-stressed basin is described. The mostly agricultural Limarí basin in arid north-central Chile was chosen as a suitable case study. The analyses involved: (1) a connectivity index method, (2) hydrochemistry, and (3) water isotopic geochemistry. Chemical and isotopic data were obtained from two sampling campaigns conducted in April (fall) and December (summer) of 2011 in 22 sampling locations, which included surface water and groundwater. The results obtained by each of the methodologies were mutually consistent and indicate high connectivity conditions. Additionally, the relative contribution by different sources was assessed through end-member mixing analysis, and for reaches of the river that showed gaining conditions, the contribution of groundwater inflow to stream discharge was estimated. It is suggested that this multi-method approach is useful for the characterization of surface-water–groundwater interactions, since it at least represents a suitable starting point for obtaining basic information on these relationships. Thus, it may become the base for further studies in arid and semi-arid basins facing water management challenges.
Año: 2014
Palabras claves: Stable isotopes, RadonOver-allocated basin, Arid regions, Chile.
Referencia APA: Oyarzún, R., Barrera, F., Salazar, P., Maturana, H., Oyarzún, J., & Aguirre, E. et al. (2014). Multi-method assessment of connectivity between surface water and shallow groundwater: the case of Limarí River basin, north-central Chile. Hydrogeol J, 22(8), 1857-1873.
Alimentos, Tecnologías Vegetales Y Paleoambiente En Las Aldeas Formativas De La Pampa Del Tamarugal, Tarapacá (ca. 900 AC-BOO DC).
García, M., Vidal, A., Mandakovic, V., Maldonado, A., Peña, M., & Belmonte, E.
Este trabajo pretende introducir a los usos e imaginarios relacionados con las plantas en las aldeas formativas de la Pampa del Tamarugal, Tarapacá (Chile). Se estudiaron los restos vegetales recuperados de las excavaciones de los sitios Pircas y Caserones, en la quebrada de Tarapacá, así como de Guatacondo 1 y Ramaditas, en la de Guatacondo. Estas aldeas poseen contextos domésticos, ceremoniales, mortuorios y de almacenaje, asociados a alimentos silvestres y cultivados, así como un amplio universo artefactual, principalmente en madera, que incluye materias primas, instrumentos y desechos de talla. Se concluye que, si bien las cuatro aldeas comparten aspectos significativos como su orientación agrícola y forestal, las ocupaciones de ambas cuencas expresan situaciones disímiles que permiten cuestionar la noción evolucionista que se ha tenido del período Formativo como una sucesión unilineal de etapas de progreso.
Año: 2014
Palabras claves: Aldeas - Prosopis - alimentos - tecnologías vegetales -período Formativo - Tarapacá.
Referencia APA: García, M., Vidal, A., Mandakovic, V., Maldonado, A., Peña, M., & Belmonte, E. (2014). Alimentos, Tecnologías Vegetales Y Paleoambiente En Las Aldeas Formativas De La Pampa Del Tamarugal, Tarapacá (ca. 900 AC-BOO DC). Estud. Atacam., (47), 33-58.
Wind effects on snow cover in Pascua-Lama, Dry Andes of Chile.
Gascoin, S., Lhermitte, S., Kinnard, C., Bortels, K., & Liston, G.
We present the first application of a distributed snow model (SnowModel) in the instrumented site of Pascua-Lama in the Dry Andes (2600–5630 m above sea level, 29° S). A model experiment was performed to assess the effect of wind on the snow cover patterns. A particular objective was to evaluate the role of blowing snow on the glacier formation. The model was run using the data from 11 weather stations over a complete snow season. First, a cross-validation of the meteorological variables interpolation model (MicroMet submodel) was performed to evaluate the performance of the simulated meteorological forcing. Secondly, two SnowModel simulations were set up: one without and the other with the wind transport submodel (SnowTran-3D). Results from both simulations were compared with in situ snow depth measurements and remotely sensed snow cover data. The inclusion of SnowTran-3D does not change the fact that the model is unable to capture the small-scale snow depth spatial variability (as captured by in situ snow depth sensors). However, remote sensing data (MODIS daily snow product) indicate that at broader scales the wind module produced an improved representation of the snow distribution near the glaciers (2-D correlation coefficient increased from R = 0.04 to R = 0.27). The model outputs show that a key process is the sublimation of blowing snow, which amounts to 18% of the total ablation over the whole study area, with a high spatial variability. The effect of snow drift is more visible on the glaciers, where wind-transported snow accumulates preferentially. Net deposition occurred for 43% of the glacier grid points, whereas it is only 23% of non-glacier grid points located above the minimum glacier altitude (4475 m).
Año: 2013
Palabras claves: Snow; Glacier; Wind; Sublimation; Andes; MODIS.
Referencia APA: Gascoin, S., Lhermitte, S., Kinnard, C., Bortels, K., & Liston, G. (2013). Wind effects on snow cover in Pascua-Lama, Dry Andes of Chile. Advances In Water Resources, 55, 25-39.
Barotropic and baroclinic semidiurnal tidal currents in two contrasting coastal upwelling zones of Chile.
Bravo, L., Ramos, M., Sobarzo, M., Pizarro, O., & Valle-Levinson, A.
Current velocity observations from the continental shelves of Coquimbo (~30°S) and Concepcion (~36°30'S), central Chile, were analyzed to evaluate the role of water column stratification and shelf width on baroclinic semidiurnal tidal currents. Semidiurnal barotropic currents off both zones were typically < 5 cm/s, but depth-dependent semidiurnal flows could exceed 10 cm s-1 during stratified conditions. Both zones are recognized as pronounced upwelling centers, with maximum upwelling-favorable winds in spring and summer, respectively. At the northern zone, stratification was mainly controlled by temperature differences between surface and bottom waters with maximum stratification during summer. The southern zone showed more stratification during winter because of freshwater input from local rivers. Consequently, greater variability in the baroclinic semidiurnal currents was observed during summer at the northern continental shelf and in winter at the south. In both regions, much of the semidiurnal variability was consistent with an internal wave's first baroclinic mode of wavelengths of ~10–13 km. Nevertheless, during the period of maximum energy fluxes off the north, the second baroclinic mode (wavelength ~7 km) was also important and matched periods of low upwelling index (relaxation of upwelling favorable winds). Typical energy fluxes during summer integrated in the water column, related to the semidiurnal internal tides were 0.12 W/m of the northern site and 0.1 W/m off the southern site. Possible sites of internal wave generation off the south were the Biobío submarine canyon and the slope/shelf break, while off the north, the generation site was the slope/shelf break.
Año: 2013
Palabras claves: Baroclinic waves; semidiurnal; energy flux.
Referencia APA: Bravo, L., Ramos, M., Sobarzo, M., Pizarro, O., & Valle-Levinson, A. (2013). Barotropic and baroclinic semidiurnal tidal currents in two contrasting coastal upwelling zones of Chile. J. Geophys. Res. Oceans, 118(3), 1226-1238
Within-population genetic diversity of climbing plants and trees in a temperate forest in central Chile.
Torres-Díaz, C., Ruiz, E., Salgado-Luarte, C., Molina-Montenegro, M., & Gianoli, E.
The climbing habit is a key innovation in angiosperm evolution: climbing plant taxa have greater species richness than their non-climbing sister groups. It is considered that highly diversified clades should show increased among-population genetic differentiation. Less clear is the expected pattern regarding within-population genetic diversity in speciose lineages. We tested the hypothesis of greater within-population genetic diversity in climbing plants compared to trees in a temperate forest in central Chile. The assumption underlying this hypothesis is that higher among-population differentiation in climbers compared to trees should reflect higher genetic diversity as well. AFLP markers from 167 individual plants from 14 species (seven climbers and seven trees) were used to estimate the following indices of within-population genetic diversity: mean unbiased expected heterozygosity (He), percentage of polymorphic loci (PPL), Shannon information index (I), and the effective number of alleles (Ne). Overall, within-population genetic diversity did not differ between climbing plants and trees. The He for climbing plants was slightly higher than that of trees (0.247 vs. 0.231), and PPL was higher in trees (93.6) than in climbers (81.8), but these differences were not statistically significant. Both I and Ne were very similar for both groups. The expected greater genetic diversity in climbers might have been counterbalanced by tree-related ecological factors that turned to be relevant in the species assemblages studied. Results of this preliminary study should be further confirmed with a broader approach including several forest sites and larger sample sizes.
Año: 2013
Palabras claves: AFLP, climbers, evolution, genetic variability, key innovation.
Referencia APA: Torres-Díaz, C., Ruiz, E., Salgado-Luarte, C., Molina-Montenegro, M., & Gianoli, E. (2013). Within-population genetic diversity of climbing plants and trees in a temperate forest in central Chile. Gayana Bot., 70(1), 36-43
Different photoprotective responses under drought conditions of two predominant Chilean swamp forest species.
Bascuñán-Godoy, L., Alcaíno, C., Carvajal, D., Sanhueza, C., Montecinos, S., & Maldonado, A.
Myrceugenia exsucca (DC.) O.Berg (Myrtaceae) and Luma chequen (Molina) A. Gray (Myrtaceae) are two predominants species from swamp forests of Chile. These species present differential microhabitat distribution across soil moisture and north-south precipitation gradients, with only L. chequen being commonly found in lower moisture sites. It is hypothesized that L. chequen has greater plasticity than M. exsucca in the attributes involved in photoprotection under drought conditions. To test this hypothesis: both species were exposed to short term drought treatment. A group of individuals was maintained irrigated (with of -0.58 and -0.73 MPa for M. exsucca and L. chequen, respectively), while another group was exposed to drought treatment with around -1.4 MPa ( D). High relationship was founded between relative water content (RWC) and water potential () forM. exsucca (r2= 0.74) more than for L. chequen (r2= 0.46), indicating thatM. exsucca experienced larger dehydration during the drought treatment. As functional attributes of photosynthetic apparatus, amount of total chlorophyll and chlorophyll a fluorescence parameter levels were studied in both species. The results show that L. chequen reduced total content of chlorophylls and maximum efficiency of PSII (Fv / Fm) related to decrease of energy capture increasing significantly the thermal dissipation (qN). On the other hand, M. exsucca does not change these parameters, but significantly reduced the level of photochemical processes (qL), indicating an energy imbalance. The results indicate M. exsucca has less plasticity than L. chequen under drought conditions. It is believed that these differences may be crucial in the establishment period and may be influencing the limited distribution ofM. exsucca in sites with lower water availability.
Año: 2013
Palabras claves: Thermal dissipation, water potential, native plants, Myrtaceae family, wetland plants.
Referencia APA: Bascuñán-Godoy, L., Alcaíno, C., Carvajal, D., Sanhueza, C., Montecinos, S., & Maldonado, A. (2013). Different photoprotective responses under drought conditions of two predominant Chilean swamp forest species. Gayana Bot., 70(2), 267-274.
Meteorological drivers of ablation processes on a cold glacier in the semi-arid Andes of Chile.
MacDonell, S., Kinnard, C., Mölg, T., Nicholson, L., & Abermann, J.
Meteorological and surface change measurements collected during a 2.5 yr period are used to calculate surface mass and energy balances at 5324 m a.s.l. on Guanaco Glacier, a cold-based glacier in the semi-arid Andes of Chile. Meteorological conditions are marked by extremely low vapour pressures (annual mean of 1.1 hPa), strong winds (annual mean of 10 m s−1), shortwave radiation receipt persistently close to the theoretical site maximum during cloud-free days (mean annual 295 W m−2; summer hourly maximum 1354 W m−2) and low precipitation rates (mean annual 45 mm w.e.). Snowfall occurs sporadically throughout the year and is related to frontal events in the winter and convective storms during the summer months. Net shortwave radiation provides the greatest source of energy to the glacier surface, and net longwave radiation dominates energy losses. The turbulent latent heat flux is always negative, which means that the surface is always losing mass via sublimation, which is the main form of ablation at the site. Sublimation rates are most strongly correlated with net shortwave radiation, incoming shortwave radiation, albedo and vapour pressure. Low glacier surface temperatures restrict melting for much of the period, however episodic melting occurs during the austral summer, when warm, humid, calm and high pressure conditions restrict sublimation and make more energy available for melting. Low accumulation (131 mm w.e. over the period) and relatively high ablation (1435 mm w.e.) means that mass change over the period was negative (−1304 mm w.e.), which continued the negative trend recorded in the region over the last few decades.
Año: 2013
Palabras claves:
Referencia APA: MacDonell, S., Kinnard, C., Mölg, T., Nicholson, L., & Abermann, J. (2013). Meteorological drivers of ablation processes on a cold glacier in the semi-arid Andes of Chile. The Cryosphere, 7(5), 1513-1526. http://dx.doi.org/10.5194/tc-7-1513-2013
Major hydrological regime change along the semiarid western coast of South America — Response to comments by Maldonado and Moreiras [page number in this issue].
Ortega, C., Vargas, G., & Rutllant, J.
Based on the sedimentology, geomorphology and geochronology of eolian and alluvial deposits at Quebrada Santa Julia (QSJ, 31°50′S) site, in a small coastal watershed in the semiarid central Chile, Ortega et al. (2012) interpreted a regional arid climate setting concomitantly with high local humidity due to reinforced coastal fog development between 13,000 and 8600 cal yr BP. Together with other continental proxies and paleo-SST records off central Chile, Ortega et al. (2012) proposed La Niña-like conditions during the latest Pleistocene‒early Holocene along this semiarid coast. A major hydrologic regime shift shortly after 8600 cal yr BP resulted in higher frequency of torrential rainfall episodes still under an arid climate setting, before the onset of El Niño at ~ 5500 cal yr BP (e.g., Rodbell et al., 1999). This hypothesis differs from that of Maldonado and Moreiras (2013) based on pollen records, who suggest humid conditions associated with precipitation around 13,000 and 10,500 cal yr BP (e.g., Maldonado et al., 2010).
Año: 2013
Palabras claves: Early Holocene; Coastal fog; Rainfall; Hydrologic change; Lifting condensation level; Sea level.
Referencia APA: Ortega, C., Vargas, G., & Rutllant, J. (2013). Major hydrological regime change along the semiarid western coast of South America — Response to comments by Maldonado and Moreiras [page number in this issue]. Quaternary Research, 80(1), 140-142.
Ecophysiological plasticity and local differentiation help explain the invasion success of Taraxacum officinale (dandelion) in South America.
Molina-Montenegro, M., Palma-Rojas, C., Alcayaga-Olivares, Y., Oses, R., Corcuera, L., Cavieres, L., & Gianoli, E.
Plasticity and local adaptation have been suggested as two main mechanisms that alien species use to successfully tolerate and invade broad geographic areas. In the present study, we try answer the question if the mechanism for the broad distributional range of T. officinale is for phenotypic plasticity, ecotypic adaptation or both. For this, we used individuals of T. officinale originated from seeds collected in five localities along its latitudinal distribution range in the southern-hemisphere. Seedlings were acclimated at 5 and 25°C for one month. After the acclimation period we evaluated ecophysiological and cytogenetic traits. Additionally, we assessed the fitness at each temperature by recording the seed output of individuals from different localities. Finally, we performed a manipulative experiment in order to assess the tolerance to herbivory and competitive ability between T. officinale from all origins and Hypochaeris scorzonerae a co-occurring native species. Overall, individuals of T. officinale showed high plasticity and ecotypic adaptation for all traits assessed in this study. Changes both in physiology and morphology observed in T. officinale from different origins were mostly correlated, enhancing their ecophysiological performance in temperatures similar to those of their origin. Additionally, all localities showed the same chromosome number and ploidy level. On the other hand, all individuals showed an increase the seed output at 25°C, but those from northern localities increased more. T. officinale from all origins was not significantly affected by herbivory while native showed a negative effect. On the other hand, T. officinale exerted a strong negative effect on the native species, but this former not effected significantly to the invasive T. officinale. High plasticity and local adaptation in all ecophysiological traits, seed-set and the low cytogenetic variability in T. officinale suggests that both strategies are present in this invasive plant species and are not mutually exclusive. Finally, higher tolerance to herbivory and competitive ability suggests that T. officinale could perform successfully in environments with different climatic conditions, and thus colonize and invade South-America.
Año: 2013
Palabras claves:
Referencia APA: Molina-Montenegro, M., Palma-Rojas, C., Alcayaga-Olivares, Y., Oses, R., Corcuera, L., Cavieres, L., & Gianoli, E. (2013). Ecophysiological plasticity and local differentiation help explain the invasion success of Taraxacum officinale (dandelion) in South America. Ecography, 36(6), 718-730.