CEAZA
Naturalised grapevines collected from arid regions in Northern Chile exhibit a high level of genetic diversity.
Milla-Tapia, A., Gómez, S., Moncada, X., León, P., Ibacache, A., & Rosas, M. et al.
Over 150 grapevine accessions were collected and characterised using 11 Simple Sequence Repeats (SSR) markers, to determine the genetic diversity and to propose a population structuring. SSR diversity was high, with observed heterozygosity (Ho = 0.87) greater than expected heterozygosity (He = 0.70). Three discrete genetic groups were identified, which did not show any association with geographical distribution. Groups 1 (G1) and G3 had a higher level of genetic diversity and also an important level of heterozygosity.
Año: 2013
Palabras claves: Arid regions; genetic structure; germplasm; naturalised grapevines; Vitis.
Referencia APA: Milla-Tapia, A., Gómez, S., Moncada, X., León, P., Ibacache, A., & Rosas, M. et al. (2013). Naturalised grapevines collected from arid regions in Northern Chile exhibit a high level of genetic diversity. Australian Journal Of Grape And Wine Research, 19(2), 299-310.
Evidencing a large body of ice in a rock glacier, Vanoise Massif, Northern French Alps.
Monnier, S., Camerlynck, C., Rejiba, F., Kinnard, C., & Galibert, P.
The Sachette rock glacier is an active rock glacier located between 2660 and 2480 m a.s.l. in the Vanoise Massif, Northern French Alps (45° 29′ N, 6° 52′ E). In order to characterize its status as permafrost feature, shallow ground temperatures were monitored and the surface velocity measured by photogrammetry. The rock glacier exhibits near-surface thermal regimes suggesting permafrost occurrence and also displays significant surface horizontal displacements (0.6–1.3 ± 0.6 m yr–1). In order to investigate its internal structure, a ground-penetrating radar (GPR) survey was performed. Four constant-offset GPR profiles were performed and analyzed to reconstruct the stratigraphy and model the radar wave velocity in two dimensions. Integration of the morphology, the velocity models and the stratigraphy revealed, in the upper half of the rock glacier, the good correspondence between widespread high radar wave velocities (>0.15–0.16 m ns–1) and strongly concave reflector structures. High radar wave velocity (0.165–0.170 m ns–1) is confirmed with the analysis of two punctual common mid-point measurements in areas of exposed shallow pure ice. These evidences point towards the existence of a large buried body of ice in the upper part of the rock glacier. The rock glacier was interpreted to result from the former advance and decay of a glacier onto pre-existing deposits, and from subsequent creep of the whole assemblage. Our study of the Sachette rock glacier thus highlights the rock glacier as a transitional landform involving the incorporation and preservation of glacier ice in permafrost environments with subsequent evolution arising from periglacial processes.
Año: 2013
Palabras claves: Rock glacier; ground-penetrating radar; ice.
Referencia APA: Monnier, S., Camerlynck, C., Rejiba, F., Kinnard, C., & Galibert, P. (2013). Evidencing a large body of ice in a rock glacier, Vanoise Massif, Northern French Alps. Geografiska Annaler: Series A, Physical Geography, 95(2), 109-123.
Late Holocene summer temperatures in the central Andes reconstructed from the sediments of high-elevation Laguna Chepical, Chile (32° S).
de Jong, R., von Gunten, L., Maldonado, A., & Grosjean, M.
High-resolution reconstructions of climate variability that cover the past millennia are necessary to improve the understanding of natural and anthropogenic climate change across the globe. Although numerous records are available for the mid- and high-latitudes of the Northern Hemisphere, global assessments are still compromised by the scarcity of data from the Southern Hemisphere. This is particularly the case for the tropical and subtropical areas. In addition, high elevation sites in the South American Andes may provide insight into the vertical structure of climate change in the mid-troposphere. This study presents a 3000 yr-long austral summer (November to February) temperature reconstruction derived from the 210Pb- and 14C-dated organic sediments of Laguna Chepical (32°16' S, 70°30' W, 3050 m a.s.l.), a high-elevation glacial lake in the subtropical Andes of central Chile. Scanning reflectance spectroscopy in the visible light range provided the spectral index R570/R630, which reflects the clay mineral content in lake sediments. For the calibration period (AD 1901–2006), the R570/R630 data were regressed against monthly meteorological reanalysis data, showing that this proxy was strongly and significantly correlated with mean summer (NDJF) temperatures (R3 yr = −0.63, padj = 0.01). This calibration model was used to make a quantitative temperature reconstruction back to 1000 BC.
The reconstruction (with a model error RMSEPboot of 0.33 °C) shows that the warmest decades of the past 3000 yr occurred during the calibration period. The 19th century (end of the Little Ice Age (LIA)) was cool. The prominent warmth reconstructed for the 18th century, which was also observed in other records from this area, seems systematic for subtropical and southern South America but remains difficult to explain. Except for this warm period, the LIA was generally characterized by cool summers. Back to AD 1400, the results from this study compare remarkably well to low altitude records from the Chilean Central Valley and southern South America. However, the reconstruction from Laguna Chepical does not show a warm Medieval Climate Anomaly during the 12–13th century, which is consistent with records from tropical South America. The Chepical record also indicates substantial cooling prior to 800 BC. This coincides with well-known regional as well as global glacier advances which have been attributed to a grand solar minimum. This study thus provides insight into the climatic drivers and temperature patterns in a region for which currently very few data are available. It also shows that since ca. AD 1400, long-term temperature patterns were generally similar at low and high altitudes in central Chile.
Año: 2013
Palabras claves:
Referencia APA: de Jong, R., von Gunten, L., Maldonado, A., & Grosjean, M. (2013). Late Holocene summer temperatures in the central Andes reconstructed from the sediments of high-elevation Laguna Chepical, Chile (32° S). Climate Of The Past, 9(4), 1921-1932. http://dx.doi.org/10.5194/cp-9-1921-2013
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.
Differential effects of grazer species on periphyton of a temperate rocky shore.
Aguilera, M., Navarrete, S., & Broitman, B.
Species-specific traits are relevant to understand variation in the effect of grazers on primary producers and are critical in determining their functional roles as controllers of productivity in marine ecosystems. In intertidal habitats, periphyton, composed of bacteria, cyanophytes, microalgae and early stages of macroalgae, constitutes the main food for many benthic grazers. Using field experiments, we examined the overall effect of grazers and the importance of direct and indirect effects of different grazer species on periphyton composition, richness, diversity and productivity. We manipulated the main grazer species present along Chilean rocky shores, enclosing adult individuals of the keyhole limpet Fissurella crassa, the chiton Chiton granosus, the scurrinid limpet Scurria araucana and the pulmonate limpet Siphonaria lessoni. These organisms overlap broadly in diet but exhibit differences in foraging behavior. Differences in the individual effects of grazer species on periphyton productivity, as well as on richness and diversity characterized the assemblage. C. granosus grazing led to lower periphyton productivity, richness and diversity compared with all other grazers, who had positive effects for all variables. Richness and diversity of the major periphyton groups were maximal at intermediate levels of total grazing pressure, highlighting the importance of ecological interactions within the periphyton assemblage. Our results demonstrate the complexity of functional roles and relationships of grazers involved in the control of composition and production of the periphyton assemblage. Given the importance of direct and indirect effects of grazers, understanding species interactions within the microbenthic community can shed light on the mechanisms through which herbivores modify community structure and productivity.
Año: 2013
Palabras claves: Grazer assemblage, Periphyton, Productivity, Diversity, Foraging behavior.
Referencia APA: Aguilera, M., Navarrete, S., & Broitman, B. (2013). Differential effects of grazer species on periphyton of a temperate rocky shore. Marine Ecology Progress Series, 484, 63-78.
Environmental and climatic changes in Central Chilean Patagonia since the Late Glacial (Mallín El Embudo, 44° S).
de Porras, M., Maldonado, A., Quintana, F., Martel-Cea, A., Reyes, O., & Méndez, C.
Multi-millennial environmental and climatic changes in central Chilean Patagonia (44–49° S) during the Last Glacial–Interglacial cycle have been of particular interest as changes in the position and strength of the southern westerlies are the major forcing factor conditioning the environmental dynamics. Recent attempts to reconstruct regional environmental and climatic signals from central Chilean Patagonia reveal some discrepancies and unclear issues among the records. This paper presents the 13 ka pollen and charcoal records from Mallín El Embudo (44° 40' S, 71° 42' W) located in the deciduous Nothofagus forest in the middle Río Cisnes valley. The paper aims to (1) establish the timing and magnitude of local vegetation changes and fire activity since the Late Glacial and (2) integrate these results at the regional scale in order to discuss the discrepancies and depict the environmental and climatic dynamics in central Chilean Patagonia since the Late Glacial. Open landscapes dominated by grasses associated with scattered Nothofagus forest patches dominated the middle Río Cisnes valley between 13 and 11.2 ka suggesting low effective moisture but also indicating that landscape configuration after glacial retreat was still ongoing. At 11.2 ka, the sudden development of an open and quite dynamic Nothofagus forest probably associated with the synchronous high fire activity occurred, suggesting a rise in effective moisture associated with dry summers. Since 9.5 ka, the record reflects the presence of a closed Nothofagus forest related to higher effective moisture conditions than before combined with moderate dry summers that may have triggered a high frequency of low-magnitude crown fires that did not severely affect the forest. The forest experienced a slight canopy opening after 5.7 ka, probably due to slightly drier conditions than before followed by a sudden change to open forest conditions around 4.2 ka associated with fire and volcanic disturbances. Around 2 ka, the recovery of a closed Nothofagus forest related to slightly wetter conditions (similar to present) occurred and persisted under highly variable climatic conditions up to 0.1 ka when massive forest burning and logging due to European settlements occurred. Central Chilean Patagonian climatic and environmental changes at millennial–centennial timescales since the Late Glacial were driven by changes in the southern westerlies latitudinal position and/or intensity, but during the late Holocene fire, volcanism and humans arose as forces contributing to environmental dynamics.
Año: 2013
Palabras claves:
Referencia APA: de Porras, M., Maldonado, A., Quintana, F., Martel-Cea, A., Reyes, O., & Méndez, C. (2013). Environmental and climatic changes in Central Chilean Patagonia since the Late Glacial (Mallín El Embudo, 44° S). Clim. Past Discuss., 9(5), 5747-5784.