CEAZA
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.
Hydrochemical and isotopic patterns in a calc-alkaline Cu- and Au-rich arid Andean basin: The Elqui River watershed, North Central Chile.
Oyarzún, J., Carvajal, M., Maturana, H., Núñez, J., Kretschmer, N., & Amezaga, Röttingd, T.S., Strauche, G., Thynef, G., Oyarzún,R.
The geochemistry of surface water and groundwater from the Elqui River basin, North-Central Chile, was studied in spring 2007 and fall 2008 to obtain a general understanding of the factors and mechanisms controlling the water chemistry of steep rivers located in mineral-rich, arid to semi arid zones. Besides its uniform intermediate igneous lithology, this basin is known for acid drainage and high As contents in the El Indio Au–Cu–As district, in its Andean head. Abundant tailings deposits are present in the middle part of the basin, where agricultural activities are important. According to the results, the chemical and isotopic composition of the Elqui basin surface water and groundwater is related to uniform calc-alkaline lithology and the major polluting system of the chemically reactive, but closed El Indio mining district. The resulting compositional imprints in surface and ground-water are, (a) high SO4 levels, reaching about 1000 mg/L in the Toro River water, directly draining the mining area; (b) a major depletion of Fe and pollutant metals in surface water after the confluence of the Toro and La Laguna rivers; (c) similar chemical composition of surface and ground-waters that differ in H and O isotopic composition, reflecting the effect of differential evaporation processes downstream of the Puclaro dam; and (d) seasonal variations of Fe, Mn, Cu and Zn in surface water. In contrast, the groundwater chemistry exhibits moderate seasonal changes, mainly in View the MathML source content. In spite of the acid drainage pollution, water quality is adequate for human consumption and irrigation. This is a consequence of both the dominant calc-alkaline lithology and the existing arid climate, resulting in neutral to moderately alkaline pH values that are responsible for the precipitation of metal hydroxides and As sorption by Fe(OH)3.
Año: 2013
Palabras claves:
Referencia APA: Oyarzún, J., Carvajal, M., Maturana, H., Núñez, J., Kretschmer, N., & Amezaga, Röttingd, T.S., Strauche, G., Thynef, G., Oyarzún, R. (2013). Hydrochemical and isotopic patterns in a calc-alkaline Cu- and Au-rich arid Andean basin: The Elqui River watershed, North Central Chile. Applied Geochemistry, 33, 50-63.
Metabolic responses of the squat lobster (Pleuroncodes monodon) larvae to low oxygen concentration.
Yannicelli, B., Paschke, K., González, R., & Castro, L.
Squat lobster populations found in the Humboldt Current System over the continental shelf from ~28 to 37°S release pelagic larvae in sub-surface cold (~11 °C) hypoxic waters. Larvae subsequently spread throughout the water column encountering both normoxic and hypoxic conditions. We analyzed some short- and long-term responses of Pleuroncodes monodon larval metabolism to hypoxia at 11 °C. Routine and postprandial aerobic respiration rates were lower in hypoxia than in normoxia for all zoeal stages. Zoea V oxyconformed, while megalopae oxyregulated down to very low oxygen concentrations. Throughout zoea I development, the rate of nitrogen (protein) accumulation in zoea I was lower, and C:N ratios were higher under hypoxic conditions than in normoxia. Citrate synthase (CS) and malate dehydrogenase (MDH) apparent specific activities (as indicators of aerobic and metabolic potentials, respectively) decreased and remained at the same level, respectively, throughout zoea I reared under hypoxic conditions. Anaerobic to aerobic potential (lactate dehydrogenase (LDH)/CS) was higher in organisms reared under hypoxia, and MDH/LDH potential ratios were characteristic of organisms tolerant to hypoxia. In spite of P. monodon zoea endurance and metabolic adaptations to decreasing oxygen tensions, intense hypoxia as such of their release site would affect their overall condition especially toward the end of the molt cycle. Our results indicate the importance of considering the interaction between environmental oxygen variability and recruitment success.
Communicated by H.-O. Portner.
Año: 2013
Palabras claves:
Referencia APA: Yannicelli, B., Paschke, K., González, R., & Castro, L. (2013). Metabolic responses of the squat lobster (Pleuroncodes monodon) larvae to low oxygen concentration. Marine Biology, 160(4), 961-976
Spatial niche differentiation and coexistence at the edge: co-occurrence distribution patterns in Scurria limpets.
Aguilera, M., Valdivia, N., & Broitman, B.
Examining the co-occurrence of taxonomically similar species can provide important information about their niches and coexistence. Segregation at smaller scales can be especially relevant for grazers living at the edge of their geographic distribution, because environmental factors can lead to similar distribution. Related grazer species may show dispersive, i.e. uniform, distribution at small scales (few centimetres) to reduce interference among individuals. We examined intra- and interspecific spatial distribution and habitat use in 2 phylogenetically related intertidal limpets, Scurria viridula and S. zebrina, at the polar and equatorial edge of their geographic distribution, respectively, and in S. araucana, a widely distributed species that overlaps the range of the other 2 species across the southeastern Pacific. S. viridula and S. zebrina overlapped in a narrow geographic zone (ca. 250 km) and reached relatively similar densities and sizes. Intraspecific spatial structure estimated through autocorrelation and individual-to-individual distances was random for S. viridula and variable for S. zebrina and S. araucana, depending on the scale considered; S. zebrina was aggregated at the individual-to-individual distances, while S. araucana was mostly random at this scale. Segregated distribution between S. viridula and S. zebrina was observed at the finer scale, whereas the association with S. araucana was random. Abundance of limpets loosely followed major habitats, namely bare rock and the alga Mazzaella laminarioides, which showed patchy distributions. We suggests that similarity in population traits between S. viridula and S. zebrina found in the overlap zone may be compensated by small-scale spatial segregation. Thus, at the edge of their geographic distribution, coexistence between related species may be influenced by spatial niche differentiation driven by habitat suitability or competition.
Año: 2013
Palabras claves: Coexistence, Geographic edge, Grazers, Habitat type, Niche partitioning, Nearest neighbour, Spatial autocorrelation.
Referencia APA: Aguilera, M., Valdivia, N., & Broitman, B. (2013). Spatial niche differentiation and coexistence at the edge: co-occurrence distribution patterns in Scurria limpets. Marine Ecology Progress Series, 483, 185-198.
Condiciones paleovegetacionales y asentamientos humanos durante el formativo temprano: análisis de polen del sitio Tulán-85 (1.530/1.260-460/420 años cal. a.c.), cuenca del Salar de Atacama.
González-Silvestre, L., Maldonado, A., Núñez, L., Cartajena, I., Carrasco, C., & de Souza, P.
Se presenta el análisis polínico obtenido de una columna estratigráfica que cubre toda la secuencia ocupacional del asentamiento formativo temprano Tulán-85 localizado al sureste del salar de Atacama fechado entre los 1.530-1.260 a 460-420 cal. a.C. Se concluye que es posible diferenciar mediante el polen actual tres pisos altitudinales de vegetación, al tanto que la comparación de las muestras fósiles con aquellas actuales sugieren condiciones de mayor humedad en la base de la secuencia, al comienzo de la fase Tilocalar (1.530-1.260 cal. a.C.). En los niveles medios comienzan los eventos áridos, identificándose al final de la columna los mayores indicadores de aridez. Los antecedentes paleoclimáticos de la alta puna señalan que las ocupaciones pastoralistas de la fase Tilocalar son sincrónicas con el establecimiento de condiciones más húmedas, lo que es concordante con los resultados del análisis polínico. Estas habrían repercutido favorablemente en las ocupaciones pastoralistas en los pisos inferiores. Es importante destacar la identificación de eventos de aridez hacia el final de la ocupación, los que no habían sido descritos con anterioridad para el área de estudio.
Año: 2013
Palabras claves: Formativo Temprano, polen fósil, condiciones húmedas, eventos áridos, salar de Atacama.
Referencia APA: González-Silvestre, L., Maldonado, A., Núñez, L., Cartajena, I., Carrasco, C., & de Souza, P. (2013). Condiciones paleovegetacionales y asentamientos humanos durante el formativo temprano: análisis de polen del sitio Tulán-85 (1.530/1.260-460/420 años cal. a.c.), cuenca del Salar de Atacama. Chungará (Arica), 45(3), 387-410.
Parameterisation of incoming longwave radiation over glacier surfaces in the semiarid Andes of Chile.
MacDonell, S., Nicholson, L., & Kinnard, C.
A good understanding of radiation fluxes is important for calculating energy, and hence, mass exchange at glacier surfaces. This study evaluates incoming longwave radiation measured at two nearby glacier stations in the high Andes of the Norte Chico region of Chile. These data are the first published records of atmospheric longwave radiation measurements in this region. Nine previously published optimised parameterisations for clear sky emissivity all produced results with a root mean square error (RMSE) ~20 W m−2 and bias within ±5 W m−2, which is inline with findings from other regions. Six optimised parameterisations for incoming longwave in all sky conditions were trialled for application to this site, five of which performed comparably well with RMSE on daytime data <18 W m−2 and bias within ±6 W m−2 when applied to the optimisation site and RMSE <20 W m−2 and bias within ±10 W m−2 when applied to the validation site. The parameterisation proposed by Mölg et al. (J Glaciol 55:292-302, 2009) was selected for use in this region. Incorporating the proposed elevation modification into the equation reduced the bias in the modelled incoming longwave radiation for the validation site. It was found that applying the parameterisation optimised in the original work at Kilimanjaro produced good results at both the primary and validation site in this study, suggesting that this formulation may be robust for different high mountain regions.
Año: 2013
Palabras claves:
Referencia APA: MacDonell, S., Nicholson, L., & Kinnard, C. (2013). Parameterisation of incoming longwave radiation over glacier surfaces in the semiarid Andes of Chile. Theoretical And Applied Climatology, 111(3-4), 513-528.