CEAZA
Water deficit stress-induced changes in carbon and nitrogen partitioning in Chenopodium quinoa Willd.
Bascuñán-Godoy, L., Reguera, M., Abdel-Tawab, Y., & Blumwald, E.
Water deficit stress followed by re-watering during grain filling resulted in the induction of the ornithine pathway and in changes in Quinoa grain quality.
The genetic diversity of Chenopodium quinoa Willd. (Quinoa) is accompanied by an outstanding environmental adaptability and high nutritional properties of the grains. However, little is known about the biochemical and physiological mechanisms associated with the abiotic stress tolerance of Quinoa. Here, we characterized carbon and nitrogen metabolic changes in Quinoa leaves and grains in response to water deficit stress analyzing their impact on the grain quality of two lowland ecotypes (Faro and BO78). Differences in the stress recovery response were found between genotypes including changes in the activity of nitrogen assimilation-associated enzymes that resulted in differences in grain quality. Both genotypes showed a common strategy to overcome water stress including the stress-induced synthesis of reactive oxygen species scavengers and osmolytes. Particularly, water deficit stress induced the stimulation of the ornithine and raffinose pathways. Our results would suggest that the regulation of C- and N partitioning in Quinoa during grain filling could be used for the improvement of the grain quality without altering grain yields.
Año: 2016
Palabras claves: C and N partitioning, Grain nutritional quality, Ornithine pathway, Quinoa, ROS scavengers, Stress recovery, Source and sink interactions, Water deficit stress.
Referencia APA: Bascuñán-Godoy, L., Reguera, M., Abdel-Tawab, Y., & Blumwald, E. (2016). Water deficit stress-induced changes in carbon and nitrogen partitioning in Chenopodium quinoa Willd. Planta, 243(3), 591-603.
3-D surface properties of glacier penitentes over an ablation season, measured using a Microsoft Xbox Kinect.
Nicholson L. I., Pętlicki M., Partan B., and MacDonell S.
In this study, the first small-scale digital surface models (DSMs) of natural penitentes on a glacier surface were produced using a Microsoft Xbox Kinect sensor on Tapado Glacier, Chile (30°08′ S, 69°55′ W). The surfaces produced by the complete processing chain were within the error of standard terrestrial laser scanning techniques, but insufficient overlap between scanned sections that were mosaicked to cover the sampled areas can result in three-dimensional (3-D) positional errors of up to 0.3 m. Between November 2013 and January 2014 penitentes become fewer, wider and deeper, and the distribution of surface slope angles becomes more skewed to steep faces. Although these morphological changes cannot be captured by manual point measurements, mean surface lowering of the scanned areas was comparable to that derived from manual measurements of penitente surface height at a minimum density of 5 m−1 over a 5 m transverse profile. Roughness was computed on the 3-D surfaces by applying two previously published geometrical formulae: one for a 3-D surface and one for single profiles sampled from the surface. Morphometric analysis shows that skimming flow is persistent over penitentes, providing conditions conducive for the development of a distinct microclimate within the penitente troughs. For each method a range of ways of defining the representative roughness element height was used, and the calculations were done both with and without application of a zero displacement height offset to account for the likelihood of skimming air flow over the closely spaced penitentes. The computed roughness values are on the order of 0.01–0.10 m during the early part of the ablation season, increasing to 0.10–0.50 m after the end of December, in line with the roughest values previously published for glacier ice. Both the 3-D surface and profile methods of computing roughness are strongly dependent on wind direction. However, the two methods contradict each other in that the maximum roughness computed for the 3-D surface coincides with airflow across the penitente lineation, while maximum roughness computed for sampled profiles coincides with airflow along the penitente lineation. These findings highlight the importance of determining directional roughness and wind direction for strongly aligned surface features and also suggest more work is required to determine appropriate geometrical roughness formulae for linearized features.
Año: 2016
Palabras claves:
Referencia APA: Nicholson L. I., Pętlicki M., Partan B., and MacDonell S. (2016). 3-D surface properties of glacier penitentes over an ablation season, measured using a Microsoft Xbox Kinect. The Cryosphere, 10(5), 1897.
Late Holocene environmental changes as recorded in the sediments of high Andean Laguna Chepical, Central Chile (32° S; 3050ma. sl).
Martel-Cea, A., Maldonado, A., Grosjean, M., Alvial, I., de Jong, R., Fritz, S. C., & von Gunten, L.
We present a reconstruction of environmental changes from sediments of high-altitude Laguna Chepical in the subtropical Andes of Central Chile (32°16′S; 70°30′W, 3050 m a.s.l.) for the past 3100 years. Based on subfossil pollen, microscopic charcoal and diatoms, we inferred changes in moisture (related to precipitation) and ice-cover/ice-free season (related to summer temperature) at decadal to millennial scales. Sustained wetter and colder summer temperatures than today prevailed between 1100 BC and ca. AD 1. Afterward, decreasing pollen accumulation rates and increased fire activity suggest drier conditions and possibly enhanced seasonality and/or inter-annual climate variability. Frequent changes between cold and warm summers were observed, particularly for the last 1000 years. About AD 1250 (during the Medieval Climate Anomaly), wet years and early break up of ice-cover occurred in central Chile, which is today typical for El Niño-like mean conditions. Conversely, and with the exception of a few wet pulses, a generally dry period with extended ice-cover (cool summers) was observed between AD 1400 and AD 1850 (Little Ice Age). This can be interpreted as a trend toward more La Niña-like mean conditions. Recent climate change and human disturbances during the last 100 years have prompted changes in diatom and plant communities that are unprecedented in the late Holocene. First, planktonic diatoms increased as a result of hydraulic interventions in the lake during the late 19th century, and secondly, the Andean vegetation shifted upward as result of recent warming, and the frequency of arboreal taxa was significantly reduced. At the same time peaks of fire activity were observed.
Año: 2016
Palabras claves: Late Holocene; ENSO; Pollen; Diatom; Andes; Climate change.
Referencia APA: Martel-Cea, A., Maldonado, A., Grosjean, M., Alvial, I., de Jong, R., Fritz, S. C., & von Gunten, L. (2016). Late Holocene environmental changes as recorded in the sediments of high Andean Laguna Chepical, Central Chile (32° S; 3050ma. sl). Palaeogeography, Palaeoclimatology, Palaeoecology, 461, 44-54.
Dairy slurry application to grasslands and groundwater quality in a volcanic soil.
Huertas, J., Cuevas, J. G., Paulino, L., Salazar, F., Arumí, J. L., & Dörner, J.
Research in volcanic-ash soils has shown that they largely capture the dairy slurry following application to land; however, their hydrological properties would favor nutrient leaching. Our objective was to evaluate the contribution of biogeochemical and hydrological controls on the pollution of groundwater by cattle slurry applied to a permanent grassland growing on a volcanic soil. We sampled groundwater chemistry since 10 months before the fertilization (three samplings), and 16 months after, with samplings 1-2 months after the fertigation. Following fertilization, ammonium, exchangeable potassium, and magnesium soil concentrations increased in the fertilized plots compared to the control plots. In contrast, no effect of slurry on groundwater quality was detected, with the exception of dissolved organic nitrogen, a main component of dairy slurry that increased in the groundwater below the fertilized plots. Despite the fact that biogeochemical controls predominate, hydrological aspects would be important when rainfall is high, evapotranspiration is low, groundwater table level is high, and water movement in the saturated zone increases. We concluded that the application of slurry to pastures under rates comparable to a high fertilization in the short term, does not generally impact the groundwater quality in volcanic ash-derived soils.
Año: 2016
Palabras claves: Andisol; groundwater pollution; hydraulic properties; saturated zone; dissolved organic nitrogen.
Referencia APA: Huertas, J., Cuevas, J. G., Paulino, L., Salazar, F., Arumí, J. L., & Dörner, J. (2016). Dairy slurry application to grasslands and groundwater quality in a volcanic soil. Journal of soil science and plant nutrition, 16(3), 745-762.
Late Quaternary climate change, relict populations and present-day refugia in the northern Atacama Desert: a case study from Quebrada La Higuera (18° S).
Mujica, M., Latorre, C., Maldonado, A., González-Silvestre, L., Pinto, R., de Pol-Holz, R., & Santoro, C.
In deserts, past climate change (and particularly past rainfall variability) plays a large role in explaining current plant species distributions. We ask which species were most and which were least affected by changes in rainfall during the late Quaternary in northernmost Chile.
Año: 2015
Palabras claves: Altiplano; Atacama Desert; central Andes; late Quaternary; pluvial events; refugia; relict populations; rodent middens.
Referencia APA: Mujica, M., Latorre, C., Maldonado, A., González-Silvestre, L., Pinto, R., de Pol-Holz, R., & Santoro, C. (2015). Late Quaternary climate change, relict populations and present-day refugia in the northern Atacama Desert: a case study from Quebrada La Higuera (18° S). Journal Of Biogeography, 42(1), 76-88.
Ancient and modern introduction of Broussonetia papyrifera ([L.] Vent.; Moraceae) into the Pacific: genetic, geographical and historical evidence.
González-Lorca, J., Rivera-Hutinel, A., Moncada, X., Lobos, S., Seelenfreund, D., & Seelenfreund, A.
Broussonetia papyrifera (L.) Vent. (Moraceae), or paper mulberry, is a species of cultural importance in South East Asia, East Asia and the Pacific. Originally from mainland South East Asia or East Asia, this plant was introduced into the Pacific range by prehistoric Austronesian voyagers. We used non-coding internal transcribed spacer (ITS) sequences of nuclear ribosomal DNA and inter-simple sequence repeat (ISSR) on 79 samples of B. papyrifera from different islands of Remote Oceania, and South East Asia and East Asia. Our results show an absence of genetic diversity in the introduced range of Remote Oceania, with the sole exception of Hawaii. By contrast, Asian samples show genetic diversity. The data obtained suggest a prehistoric human-mediated introduction of this species from East Asia to Remote Oceania and a second, possibly historic, human-mediated introduction to Hawaii.
Año: 2015
Palabras claves: Asia, human-mediated dispersal, ISSR, ITS, paper mulberry, Polynesia.
Referencia APA: González-Lorca, J., Rivera-Hutinel, A., Moncada, X., Lobos, S., Seelenfreund, D., & Seelenfreund, A. (2015). Ancient and modern introduction of Broussonetia papyrifera ([L.] Vent.; Moraceae) into the Pacific: genetic, geographical and historical evidence. New Zealand Journal Of Botany, 53(2), 75-89
Sampling of riverine litter with citizen scientists — findings and recommendations.
Rech, S., Macaya-Caquilpán, V., Pantoja, J., Rivadeneira, M., Campodónico, C., & Thiel, M.
The quantity and composition of litter at riversides and in the surface waters, as well as the occurrence of illegal dumping sites, were studied along four rivers in Chile. Data generated by volunteers were compared to the results from a professional survey, using an identical protocol. Litter was found in considerable quantities at the riversides and in the surface waters at all the sites investigated. A generalized linear mixed model analysis showed that the recorded litter densities did not differ between volunteers and professionals, even after controlling for river, site, or distance between sampling locations, demonstrating that the volunteers successfully applied the sampling protocol. Differences occurred with respect to litter composition, which is most likely due to difficulties in the classification of litter items and particles and to the underestimation of litter present in surface water samples. Even though this study was only conducted at a small number of rivers and sites, a comparatively consistent pattern of direct and intentional litter deposition at riversides was recorded, highlighting that river basins require more protection. The results also show that the citizen science approach can be a suitable means for more extensive litter surveys at riversides and in other natural environments.
Año: 2015
Palabras claves: Citizen science, Data validation, Litter abundance, Litter sources, Riverine litter, Floating microplastics.
Referencia APA: Rech, S., Macaya-Caquilpán, V., Pantoja, J., Rivadeneira, M., Campodónico, C., & Thiel, M. (2015). Sampling of riverine litter with citizen scientists — findings and recommendations. Environmental Monitoring And Assessment, 187(6).
Geographic patterns of diversification and the latitudinal gradient of richness of rocky intertidal gastropods: the ‘into the tropical museum’ hypothesis.
Rivadeneira, M., Alballay, A., Villafaña, J., Raimondi, P., Blanchette, C., & Fenberg, P.
The existence of a canonical LGR in rocky intertidal gastropods can be explained by the combined effect of reduced extinction rates in the tropics and the range expansion of taxa from the extra-tropics toward the tropics, in what we have called the ‘into the tropical museum’ hypothesis.
Año: 2015
Palabras claves: Biodiversity; dispersal; diversification dynamics; extinction; fossil record; origination.
Referencia APA: Rivadeneira, M., Alballay, A., Villafaña, J., Raimondi, P., Blanchette, C., & Fenberg, P. (2015). Geographic patterns of diversification and the latitudinal gradient of richness of rocky intertidal gastropods: the ‘into the tropical museum’ hypothesis. Global Ecology And Biogeography, 24(10), 1149-1158.
Mid Holocene radiocarbon ages in the Subtropical Andes (∼29°–35° S), climatic change and implications for human space organization.
Méndez, C., Gil, A., Neme, G., Nuevo Delaunay, A., Cortegoso, V., & Huidobro, C., Durán, V., Maldonado, A.
This article discusses the distribution of radiocarbon age signatures obtained from archeological sites between 29° and 35° S in Central Chile and Midwest Argentina. The goal of this analysis is to establish bases from which to interpret regional trends in the distribution of the archaeological record that connect these areas, which have been traditionally considered to be geographically decoupled. We propose a standardized methodology for selecting ages that provide a reliable human signature. Variations in date frequencies in a regional scale are discussed with the use of summed probability distributions. Radiocarbon voids at the regional level previously identified in Midwest Argentina are explored. Regional chronological information is compared to the available paleoenvironmental records, thereby emphasizing the possible role of climate pulses in the spatial organization of human populations. Significant arid conditions between 7800 and 5700 cal BP are coincidental with a focused occupation of the Andes Mountains, an area which may have offered stable resources and thus was more effectively occupied than other environmental bands.
Año: 2015
Palabras claves: Radiocarbon dates; Climate change; Human paleoecology; Hunter–gatherers; Mid-Holocene; Subtropical Andes.
Referencia APA: Méndez, C., Gil, A., Neme, G., Nuevo Delaunay, A., Cortegoso, V., Huidobro, C., Durán, V. & Maldonado, A. (2015). Mid Holocene radiocarbon ages in the Subtropical Andes (∼29°–35° S), climatic change and implications for human space organization. Quaternary International, 356, 15-26.
Positive interactions by cushion plants in high mountains: fact or artifact?.
Molina-Montenegro, M., Oses, R., Acuña-Rodríguez, I., Fardella, C., Badano, E., & Torres-Morales, P. et al.
Positive interactions are defined as non-trophic interactions where at least one of the interacting species is benefited in terms of fitness and the other remains unaffected. Nevertheless, the bidirectional feedbacks between species may be positive, neutral or negative. Thus, if facilitated species induce negative effects on their ‘nurses’, the assumed definition of positive interactions could be reconsidered.
Año: 2015
Palabras claves: Cushion plants, facilitation, nurse effect, positive interactions, stress gradient hypothesis.
Referencia APA: Molina-Montenegro, M., Oses, R., Acuña-Rodríguez, I., Fardella, C., Badano, E., & Torres-Morales, P. et al. (2015). Positive interactions by cushion plants in high mountains: fact or artifact?. Journal Of Plant Ecology, 9(2), 117-123
Reproduction reduces HSP70 expression capacity in Argopecten purpuratus scallops subject to hypoxia and heat stress.
Brokordt, K., Pérez, H., Herrera, C., & Gallardo, A.
In scallops, gonad production is highly demanding energetically, and reproduction usually occurs during spring-summer, a period of strong environmental changes. The synthesis of heat-shock proteins (HSPs) is a major mechanism of stress tolerance in animals, including scallops, and HSP expression contributes considerably to cellular energy demand. Therefore, reproductive investment may limit the availability of energy (in terms of ATP) for the expression of HSP in organisms exposed to environmental stress. We evaluated the stress response capacity of adult Argopecten purpuratus scallops to high temperature and hypoxia. Stress response capacity was assessed through gene expression (for temperature stress) and protein induction of 70 kD HSP at 3 reproductive stages: immature, mature and spawned. We also evaluated the effect of reproductive status on the cellular ATP provisioning capacity through citrate synthase activity. Immature scallops exposed to thermal stress showed 1.3- and 1.5-fold increases in hsp70 mRNA and HSP70 protein levels, respectively, and those exposed to hypoxia doubled their level of HSP70 compared to non-stressed immature scallops. However, following gonad maturation and spawning, hsp70 mRNA increased by only 0.49- and 0.65-fold, respectively, after thermal stress and HSP70 protein levels of scallops exposed to thermal and hypoxia stressors did not differ from those of non-stressed animals. In parallel, citrate synthase showed its highest level in immature scallops, declined with gonad maturation, and was lowest in spawned scallops. These results suggest that reproductive investment reduces the stress response capacity of A. purpuratus and that mature and spawned scallops could be more vulnerable to environmental stressors than immature individuals.
Año: 2015
Palabras claves: Reproductive cost, HSP70, hsp70 mRNA, Stress response, Thermal stress, Hypoxia stress, Scallops, Argopecten purpuratus.
Referencia APA: Brokordt, K., Pérez, H., Herrera, C., & Gallardo, A. (2015). Reproduction reduces HSP70 expression capacity in Argopecten purpuratus scallops subject to hypoxia and heat stress. Aquat. Biol., 23(3), 265-274.
Estudio de la relación polen-vegetación actual en el Norte de Chile, en el transecto Pozo Almonte-Salar de Huasco (20º15’S/69º06’O).
Collao-alvarado, K., Maldonado, A., González, L., Sandoval, A., De Porras, M., Zamora, A., & Arancio, G.
La diversidad vegetal de la zona andina del Norte Grande de Chile ha sido estudiada desde diversos puntos de vista (florísticos, fisonómicos, etnobotánicos, conservacionistas, etc.); sin embargo, hasta ahora no se ha estudiado desde un punto de vista palinológico. Así, este trabajo tiene como objetivo aportar al conocimiento de la vegetación y su señal polínica en los distintos pisos altitudinales del Norte Grande de Chile, aportando además a la identificación de los principales tipos polínicos presentes. Este estudio presenta la relación entre lluvia de polen y vegetación actual en un transecto altitudinal entre Pozo Almonte y el Salar de Huasco, en el norte de Chile, junto con fotografías y descripciones de 12 morfotipos polínicos representativos de la zona. Los resultados de los muestreos de vegetación corroboran las tendencias descritas en trabajos previos identificándose los principales pisos de vegetación descritos anteriormente (piso prepuneño, puneño, altoandino y subnival). De igual manera los resultados de la lluvia de polen muestran una clara relación con los ensambles de vegetación que la produce, siendo posible diferenciar cada uno de los pisos de vegetación a partir de su señal polínica. Así, los resultados pueden ser de gran interés para la interpretación de registros polínicos fósiles o para estudios de carácter ecológico.
Año: 2015
Palabras claves: Palinología, lluvia de polen, pisos altitudinales, diversidad vegetal.
Referencia APA: Collao-alvarado, K., Maldonado, A., González, L., Sandoval, A., De Porras, M., Zamora, A., & Arancio, G. (2015). Estudio de la relación polen-vegetación actual en el Norte de Chile, en el transecto Pozo Almonte-Salar de Huasco (20º15’S/69º06’O). Gayana Bot., 72(1), 125-136.