CEAZA
Physiological performance of juvenile Haliotis rufescens and Haliotis discus hannai abalone exposed to the withering syndrome agent.
González, R., Brokordt, K., & Lohrmann, K.
Withering syndrome (WS) is a serious chronic disease caused by infection with the bacterium Candidatus Xenohaliotis californiensis, a Rickettsiales-like organism (WS-RLO) that affects multiple abalone species in both natural and farmed populations. However, there is no available information regarding the effects of this disease on the physiological performance of infected abalone. We studied the effect of different levels of infection on components of energy balance and physiological indices (rates of absorption and assimilation, O/N ratio, and scope for growth) in the abalone species Haliotis rufescens and Haliotis discus hannai. Juveniles were exposed to C. X. californiensis transmission for 130 days, during which time the presence/absence of WS-RLOs was evaluated by PCR (following DNA sequencing-based confirmation of 100% identity with the sequence of C. X. californiensis from California), and the prevalence and intensity of infection were evaluated via histological analysis. Among H. rufescens juveniles exposed to the bacterium, 92% became infected (positive by histology), and the intensity of infection ranged from low (degree 1) to moderate (degree 2). In contrast, no H. discus hannai juveniles were positive for WS-RLO by histology, although 23% were positive by PCR, possibly indicating incipient WS-RLO infection that did not develop during the experimental period or to mere presence of WS-RLO DNA in the sample. Infection of H. rufescens juveniles by WS-RLOs negatively affected all components of the energy balance and physiological indices, such as scope for growth and the O/N ratio, in direct relation to the degree of infection. The most strongly affected functions were the rate of ingestion, standard metabolism, and production of feces, which were reduced by 60–80% in the most highly infected individuals. The reduced energy intake in the organisms produced a strong energy imbalance such that the energy available for growth was reduced by 49% in infected organisms. In contrast, juveniles of H. discus hannai carrying the bacterium developed no infection and showed no alterations of physiological function. Our results indicate that the level of early infection by WS-RLOs may exert a negative effect on physiological activity in H. rufescens, even when the disease is not evident.
Año: 2012
Palabras claves: Withering syndrome; Candidatus Xenohaliotis californiensis; Abalone; Haliotis rufescens; Haliotis discus hannai; Physiological performance
Referencia APA: González, R., Brokordt, K., & Lohrmann, K. (2012). Physiological performance of juvenile Haliotis rufescens and Haliotis discus hannai abalone exposed to the withering syndrome agent. Journal Of Invertebrate Pathology, 111(1), 20-26.
Postglacial vegetation, fire and climate dynamics at Central Chilean Patagonia (Lake Shaman, 44°S).
de Porras, M., Maldonado, A., Abarzúa, A., Cárdenas, M., Francois, J., & Martel-Cea, A. et al.
A 19 cal ka BP pollen and charcoal record from Lake Shaman (44°S; 71°W, Chile) was analyzed to establish vegetation, fire and climate dynamics of the forest-steppe ecotone in Central Chilean Patagonia. Lake Shaman record indicates that the upper Río Cisnes valley was free of ice at around 19 cal ka BP. From this date and until 14.8 cal ka BP, a grass steppe with high proportions of shrubs associated to colder and drier conditions than present developed in this area. A continuous increase of Nothofagus accompanied by a decline in the steppe shrubs and sudden dominance of paludal over aquatic plants from 11 cal ka BP was associated to effective moisture increase but still under modern values. The replacement of the cold-dry grass-shrub steppe by a similar-than-present forest-steppe ecotone suggests an increase in temperature indicating the onset of the Holocene. At the same time, moderate fire activity suggested by the charcoal record could be related to major fuel availability as consequence of Nothofagus forest expansion. Between 8 and 3 cal ka BP, the record indicates the easternmost position of the forest-steppe ecotone suggesting the highest effective moisture with the establishment of seasonality between 5 and 3 cal ka BP. From 3 cal ka BP, the record indicates a retraction of the forest-steppe ecotone accompanied by a high pollen record variability and an increased fire activity. These late changes suggest decreased effective moisture associated with a high climatic variability. At regional and extra-regional scale, climatic changes at Lake Shaman's record are mostly associated to changes (latitudinal shifts and/or strengthening/weakening) of past Southern Westerlies that were previously recorded along Patagonia from the Lateglacial to the mid-Holocene. During the Late Holocene, a regional pattern characterized by high record variability emerges throughout Central Chilean Patagonia. This variability would be related to (1) low magnitude Southern Westerlies changes probably associated to ENSO and/or SAM or (2) the complex relationships between vegetation, fire and human occupations during the last 3 cal ka.
Año: 2012
Palabras claves: Forest-steppe ecotone; Central Chilean Patagonia; Southern Westerlies; Lateglacial
Referencia APA: de Porras, M., Maldonado, A., Abarzúa, A., Cárdenas, M., Francois, J., & Martel-Cea, A. et al. (2012). Postglacial vegetation, fire and climate dynamics at Central Chilean Patagonia (Lake Shaman, 44°S). Quaternary Science Reviews, 50, 71-85.
Temporal variability of incidental solar radiation and modulating factors in a coastal upwelling area (36°S).
Hernández, K., Yannicelli, B., Montecinos, A., Ramos, M., González, H., & Daneri, G.
In this study, we quantify the annual and synoptic variability of solar radiation (PAR and UVR) for southern-central Chile at ∼36.5°S from 2003 to 2004 and we relate these fluctuations to total ozone concentration, cloudiness, and winds. Data considered approximately 2 years of daily visible PAR (400–700 nm), UVA (400–320 nm), and UVB (280–320 nm). Satellite ozone data were also compared with a 305/340 ratio. On an annual scale, the visible and UV radiation co-varied in phase, with maxima in spring–summer and lower values in autumn–winter. Winds and cloudiness also showed an annual cycle, with predominantly southerly winds and lower cloudiness in summer. On a synoptic scale, solar radiation was coupled with cloudiness and winds, a relationship that is also evidenced over large scale atmospheric circulation. A 3-month lag was observed between solar radiation and ozone annual cycles; the latter peaked in springtime. The 305/340 ratio was a good ozone index over short time scales, showing fluctuations at the same frequencies as ozone and good cross-correlations once the annual cycle was extracted. The spatial–temporal analysis supports the possibility that the local pattern observed might be common for other important upwelling sites affected by the same type of atmospheric variability. Finally, this study showed that solar radiation wavelengths fluctuating at similar frequencies as those of upwelling favorable winds, are likely to be modulating biological processes in the coastal upwelling area off Concepción over short time scales.
Año: 2012
Palabras claves:
Referencia APA: Hernández, K., Yannicelli, B., Montecinos, A., Ramos, M., González, H., & Daneri, G. (2012). Temporal variability of incidental solar radiation and modulating factors in a coastal upwelling area (36°S). Progress In Oceanography, 92-95, 18-32.
Emergence of social complexity among coastal hunter-gatherers in the Atacama Desert of northern Chile.
Marquet, P., Santoro, C., Latorre, C., Standen, V., Abades, S., & Rivadeneira, M. et al.
The emergence of complex cultural practices in simple hunter-gatherer groups poses interesting questions on what drives social complexity and what causes the emergence and disappearance of cultural innovations. Here we analyze the conditions that underlie the emergence of artificial mummification in the Chinchorro culture in the coastal Atacama Desert in northern Chile and southern Peru. We provide empirical and theoretical evidence that artificial mummification appeared during a period of increased coastal freshwater availability and marine productivity, which caused an increase in human population size and accelerated the emergence of cultural innovations, as predicted by recent models of cultural and technological evolution. Under a scenario of increasing population size and extreme aridity (with little or no decomposition of corpses) a simple demographic model shows that dead individuals may have become a significant part of the landscape, creating the conditions for the manipulation of the dead that led to the emergence of complex mortuary practices.
Año: 2012
Palabras claves: climate variability, coastal desert, cultural evolution
Referencia APA: Marquet, P., Santoro, C., Latorre, C., Standen, V., Abades, S., & Rivadeneira, M. et al. (2012). Emergence of social complexity among coastal hunter-gatherers in the Atacama Desert of northern Chile. Proceedings Of The National Academy Of Sciences, 109(37), 14754-14760. http://dx.doi.org/10.1073/pnas.1116724109
Plasticidad fenotípica en dos poblaciones antárticas de Colobanthus quitensis (Caryophyllaceae) bajo un escenario simulado de cambio global
Molina-Montenegro, M., Torres-Díaz, C., Carrasco-Urra, F., González-Silvestre, L., & Gianoli, E.
La Antártica se caracteriza por presentar condiciones ambientales extremas, lo cual limita el establecimiento de las plantas vasculares. Dentro de dichas características ambientales están las bajas temperaturas, corta estación de crecimiento y el estrés hídrico y nutricional. La baja disponibilidad hídrica ha sido sugerida como la principal limitante para el éxito de establecimiento, debido a que afecta de manera negativa las respuestas fisiológicas y reproductivas de las plantas. Colobanthus quitensis (Kunth) Bartl. (Caryophyllaceae) es una de las dos plantas vasculares nativas que habitan la Antártica Marítima y se ha demostrado que su desempeño fisiológico y reclutamiento es afectado negativamente por el estrés hídrico del suelo. La plasticidad fenotípica y la adaptación local serían dos de las principales estrategias de C. quitensis para lidiar con las adversas condiciones ambientales que predominan en el continente antártico. Se ha documentado que, bajo un escenario futuro de cambio climático, la disponibilidad hídrica en la Antártica aumentaría entre un 30-40%, mejorando las condiciones para el establecimiento. En el presente trabajo evaluamos mediante un experimento de jardín común, realizado en cámaras de crecimiento, la plasticidad morfo-fisiológica y el esfuerzo reproductivo en individuos de C. quitensis provenientes de dos sitios en las Islas Shetland, bajo un escenario simulado de cambio climático (aumento en un 40% de la disponibilidad hídrica) y bajo la situación actual (disponibilidad hídrica registrada en los sitios de origen). En general, los individuos de C. quitensis de ambos sitios presentaron evidencia de plasticidad, aumentando su eficiencia fotoquímica, largo y ancho foliar, y esfuerzo reproductivo bajo la condición de aumento en la disponibilidad hídrica. La magnitud del aumento en la respuesta plástica fue mayor en aquellos individuos provenientes del sitio más árido en comparación a sus con-específicos del sitio más húmedo. Si los actuales patrones de cambio climático se mantienen, las condiciones abióticas podrían volverse más favorables para C. quitensis, mejorando su desempeño ecofisiológico y permitiendo la expansión de su rango de distribución sobre la Antártica.
Año: 2012
Palabras claves: Antártica, esfuerzo reproductivo, estrés hídrico, Fv / Fm, islas Shetland.
Referencia APA: Molina-Montenegro, M., Torres-Díaz, C., Carrasco-Urra, F., González-Silvestre, L., & Gianoli, E. (2012). Plasticidad fenotípica en dos poblaciones antárticas de Colobanthus quitensis (Caryophyllaceae) bajo un escenario simulado de cambio global. Gayana Bot., 69(1), 152-160.
Cold-acclimation limits low temperature induced photoinhibition by promoting a higher photochemical quantum yield and a more effective PSII restoration in darkness in the Antarctic rather than the Andean ecotype of Colobanthus quitensis Kunt Bartl (Cariophyllaceae)
Bascuñán-Godoy, L., Sanhueza, C., Cuba, M., Zuñiga, G., Corcuera, L., & Bravo, L.
Ecotypes of Colobanthus quitensis Kunt Bartl (Cariophyllaceae) from Andes Mountains and Maritime Antarctic grow under contrasting photoinhibitory conditions, reaching differential cold tolerance upon cold acclimation. Photoinhibition depends on the extent of photodamage and recovery capability. We propose that cold acclimation increases resistance to low-temperature-induced photoinhibition, limiting photodamage and promoting recovery under cold. Therefore, the Antarctic ecotype (cold hardiest) should be less photoinhibited and have better recovery from low-temperature-induced photoinhibition than the Andean ecotype. Both ecotypes were exposed to cold induced photoinhibitory treatment (PhT). Photoinhibition and recovery of photosystem II (PSII) was followed by fluorescence, CO2 exchange, and immunoblotting analyses.
Año: 2012
Palabras claves: Antarctic plants, Andean plants, Cold-induced-photoinhibition, Recovery, PSII restoration, D1 cycle, Photoprotection
Referencia APA: Bascuñán-Godoy, L., Sanhueza, C., Cuba, M., Zuñiga, G., Corcuera, L., & Bravo, L. (2012). Cold-acclimation limits low temperature induced photoinhibition by promoting a higher photochemical quantum yield and a more effective PSII restoration in darkness in the Antarctic rather than the Andean ecotype of Colobanthus quitensis Kunt Bartl (Cariophyllaceae). BMC Plant Biol, 12(1), 114.
Occurrence of the Non-Native Annual Bluegrass on the Antarctic Mainland and Its Negative Effects on Native Plants.
Molina-Montenegro, M., Carrasco-Urra, F., Rodrigo, C., Convey, P., Valladares, F., & Gianoli, E.
Few non-native species have colonized Antarctica, although increased human activity and accelerated climate change may increase their number, distributional range, and effects on native species on the continent. We searched 13 sites on the maritime Antarctic islands and 12 sites on the Antarctic Peninsula for annual bluegrass (Poa annua), a non-native flowering plant. We also evaluated the possible effects of competition between P. annua and 2 vascular plants native to Antarctica, Antarctic pearlwort (Colobanthus quitensis) and Antarctic hairgrass (Deschampsia antarctica). We grew the native species in experimental plots with and without annual bluegrass under conditions that mimicked the Antarctic environment. After 5 months, we measured photosynthetic performance on the basis of chlorophyll fluorescence and determined total biomass of both native species. We found individual specimens of annual bluegrass at 3 different sites on the Antarctic Peninsula during the 2007–2008 and 2009–2010 austral summers. The presence of bluegrass was associated with a statistically significant reduction in biomass of pearlwort and hairgrass, whereas the decrease in biomass of bluegrass was not statistically significant. Similarly, the presence of bluegrass significantly reduced the photosynthetic performance of the 2 native species. Sites where bluegrass occurred were close to major maritime routes of scientific expeditions and of tourist cruises to Antarctica. We believe that if current levels of human activity and regional warming persist, more non-native plant species are likely to colonize the Antarctic and may affect native species.
Año: 2012
Palabras claves: Colobanthus quitensis;Deschampsia antarctica;hairgrass;non-native species;pearlwort;species competition;tourism;Poa annuaColobanthus quitensis;competencia de especies;Deschampsia antarctica;especie no nativa;Poa annua;turismo
Referencia APA: Molina-Montenegro, M., Carrasco-Urra, F., Rodrigo, C., Convey, P., Valladares, F., & Gianoli, E. (2012). Occurrence of the Non-Native Annual Bluegrass on the Antarctic Mainland and Its Negative Effects on Native Plants. Conservation Biology, 26(4), 717-723.
Linking Climatic Variability with Spatial Performance in Two Varieties of Quinoa Distributed in a Semi-Arid Zone.
Montecinos, S., Salinas, P., Oses, R., González-Silvestre, L., & Molina-Montenegro, M.
Different crop varieties can respond in different ways to the climatic variations at local scale. Thus, in order to maximize
the yield for a determined crop, the response of different varieties submitted to local climatic conditions should be
assessed. The main goal of this study was to evaluate the ecophysiological responses of two varieties of Quinoa (PRP
and BO78) submitted to different conditions of thermal amplitude. We performed two experiments in both greenhouse
and in 3 sites on experimental-field where were evaluated survival, photochemical efficiency, plant growth and dry
biomass in both varieties and compared them with the mean of the thermal conditions recorded during the last 16 years
in the Coquimbo Region, Chile. Overall, individuals of BO78 showed higher performance in the sites with lower thermal
amplitude than those of PRP. By contrast, in sites with higher thermal amplitude individuals of PRP showed better
survival, physiological performance and biomass and therefore higher performance. Our results suggest that while
BO78 showed an ecotypic strategy, the PRP showed a plastic strategy to maintain higher performance in sites with
moderate and high climatic variability. We consider that under an increase in desertification, semi-arid areas would be
available for stress tolerant crops like Quinoa, but the success for the food security in these regions may depend upon
the variety used.
Año: 2012
Palabras claves: Quinoa; Thermal Amplitude; Plasticity; Ecophysiology; Crop Yield
Referencia APA: Montecinos, S., Salinas, P., Oses, R., González-Silvestre, L., & Molina-Montenegro, M. (2012). Linking Climatic Variability with Spatial Performance in Two Varieties of Quinoa Distributed in a Semi-Arid Zone. AJPS, 03(12), 1682-1687.
Latitudinal Patterns in Phenotypic Plasticity and Fitness-Related Traits: Assessing the Climatic Variability Hypothesis (CVH) with an Invasive Plant Species.
Molina-Montenegro, M. & Naya, D.
Phenotypic plasticity has been suggested as the main mechanism for species persistence under a global change scenario, and also as one of the main mechanisms that alien species use to tolerate and invade broad geographic areas. However, contrasting with this central role of phenotypic plasticity, standard models aimed to predict the effect of climatic change on species distributions do not allow for the inclusion of differences in plastic responses among populations. In this context, the climatic variability hypothesis (CVH), which states that higher thermal variability at higher latitudes should determine an increase in phenotypic plasticity with latitude, could be considered a timely and promising hypothesis. Accordingly, in this study we evaluated, for the first time in a plant species (Taraxacum officinale), the prediction of the CVH. Specifically, we measured plastic responses at different environmental temperatures (5 and 20°C), in several ecophysiological and fitness-related traits for five populations distributed along a broad latitudinal gradient. Overall, phenotypic plasticity increased with latitude for all six traits analyzed, and mean trait values increased with latitude at both experimental temperatures, the change was noticeably greater at 20° than at 5°C. Our results suggest that the positive relationship found between phenotypic plasticity and geographic latitude could have very deep implications on future species persistence and invasion processes under a scenario of climate change.
Año: 2012
Palabras claves: Biogeography, Latitude, Invasive species, Phenotypes, Climate change, Seeds, Photosynthetic efficiency, Plants.
Referencia APA: Molina-Montenegro, M. & Naya, D. (2012). Latitudinal Patterns in Phenotypic Plasticity and Fitness-Related Traits: Assessing the Climatic Variability Hypothesis (CVH) with an Invasive Plant Species. Plos ONE, 7(10), e47620.
Higher plasticity in ecophysiological traits enhances the performance and invasion success of Taraxacum officinale (dandelion) in alpine environments
Molina-Montenegro, M., Peñuelas, J., Munné-Bosch, S., & Sardans, J.
Phenotypic plasticity has long been suggested to facilitate biological invasions in changing environments, allowing a species to maintain a good ecophysiological performance. High-mountain habitats have been particularly useful for evaluation of the relative importance of environmental conditions in the colonization and invasion process, because they have heterogeneous and stressful climatic conditions, inducing photoinhibition. Light intensity is one of the most changing conditions along altitudinal gradients, showing more variability in higher altitudes. In this study, we analyzed the plasticity in photoprotective strategies and performance of the invasive Taraxacum officinale. Additionally, we tested whether higher plasticity enhances competitive ability in an alpine environment We conducted an experiment to evaluate plasticity with a second generation (F2) of T. officinale individuals from 1,600 to 3,600 m, in a greenhouse with variation in light intensity. Treatments consisted of transferring 120 individuals from each altitude to two conditions of light intensity. We then recorded concentrations of photoprotection pigment, de-epoxidation state of the xanthophyll cycle, foliar angles, photochemical efficiency by fluorescence of photosystem II, total dry biomass and flower production. Additionally, we compared plasticity in both photoprotective and performance traits between T. officinale and the co-occurring native species Hypochaeris thrincioides. Finally, we performed a manipulative experiment under two light regimes in order to assess the competitive outcome between the invasive T. officinale and the native H. thrincioides. Individuals from higher altitude showed significantly greater plasticity than individuals from lower altitude. Similarly, individuals under high light intensity showed higher levels of photoprotective pigments, biomass and flower production. On the other hand, the invasive plant species showed significantly greater plasticity than the co-occurring native species, and a strong negative impact on the biomass of the native plant. Phenotypic plasticity seems to be a successful strategy in T. officinale to compete with native species and may be positively associated with the success of invasions, being greater in individuals from more heterogeneous and stressful environments.
Año: 2012
Palabras claves: Altitudinal gradientCompetitionFluorescenceLight intensityPhotoprotective pigmentsXanthophyll cycle
Referencia APA: Molina-Montenegro, M., Peñuelas, J., Munné-Bosch, S., & Sardans, J. (2012). Higher plasticity in ecophysiological traits enhances the performance and invasion success of Taraxacum officinale (dandelion) in alpine environments. Biol Invasions, 14(1), 21-33.
Modelling the Water Sorption Isotherms of Quinoa Seeds (Chenopodium quinoa Willd.) and Determination of Sorption Heats.
Miranda, M., Vega-Gálvez, A., Sanders, M., López, J., Lemus-Mondaca, R., Martínez, E., & Di Scala, K.
Adsorption and desorption isotherms of quinoa seeds (Chenopodium quinoa Willd.) were measured using the static gravimetric method at three temperatures (20, 40 and 60 °C). Water activity ranged from 0.118 to 0.937. The moisture sorption behaviour of quinoa was temperature dependent, as indicated by a decrease in equilibrium moisture content, at all levels of aw, with increasing temperature. Eight mathematical equations available in the literature were used to model the experimental data, namely, GAB, BET, Caurie, Henderson, Oswin, Halsey, Smith and Iglesias–Chirife. All the equations showed generally a good fit; however, the Iglesias–Chirife and Oswin equations were considered the best to predict the experimental data for both isotherms. Effect of temperature on model parameters was analysed and studied through an Arrhenius-type equation. The net isosteric heats of desorption and adsorption were determined by applying the Clausius–Clapeyron equation resulting in 69.24 kJ mol−1 for desorption and 61.26 kJ mol−1 for adsorption. The experimental heat data were satisfactorily modelled by Tsami’s equation.
Año: 2012
Palabras claves: Quinoa, Sorption isotherms, Isosteric sorption heat, Mathematical modelling.
Referencia APA: Miranda, M., Vega-Gálvez, A., Sanders, M., López, J., Lemus-Mondaca, R., Martínez, E., & Di Scala, K. (2012). Modelling the Water Sorption Isotherms of Quinoa Seeds (Chenopodium quinoa Willd.) and Determination of Sorption Heats. Food Bioprocess Technol, 5(5), 1686-1693.
Determinants of the diversity of plants, birds and mammals of coastal islands of the Humboldt current systems: implications for conservation.
Luna-Jorquera, G., Fernández, C., & Rivadeneira, M.
Sound conservation plans for islands require understanding the processes underlying to the patterns of species richness and composition. Larger islands are often the targets of conservation assuming that the island area mainly determines species richness, and that species composition is nested across islands. However, in small-island these patterns could be altered because of stochastic processes, and species assemblages could be disharmonious. In addition, human impact could further modify the distribution pattern and diversity. Here we use the case of seven islands from the coastal system of Coquimbo as a model to address the role of environmental variables and human impacts on species richness and assembly rules of plants, birds, and mammals. We hypothesize (a) the existence of a small-island effect, and the prevalence of habitat diversity and anthropogenic impacts as main drivers of species richness, and (b) the existence of disharmonious assemblages, characterized by a low degree of nestedness and random patterns of species co-occurrence. Our results showed that (a) species richness is mainly correlated with habitat diversity, and only weakly related to island area supporting the ‘small-island effect’ and (b) species composition is highly structured, but that such structure may be the result of anthropogenic activities. Nestedness was observed in plants and landbirds, while co-occurrence patterns were only detected in plants. Assemblages in small-islands departed from the nestedness pattern and maintain rare species. Currently, only three of the seven islands are protected by national regulations, excluding the smaller ones that are subjected to human disturbance and invasive mammals. Our study suggests that it necessary to include all the islands in a major protected area to preserve both richness and species composition of a number of representative islands of the Humboldt current systems. We showed that conservation plans solely based on island area might not be robust.
Año: 2012
Palabras claves: Humboldt, current, Conservation, Small-island effect, Island biogeography.
Referencia APA: Luna-Jorquera, G., Fernández, C., & Rivadeneira, M. (2012). Determinants of the diversity of plants, birds and mammals of coastal islands of the Humboldt current systems: implications for conservation. Biodiversity And Conservation, 21(1), 13-32.