CEAZA
Artificial breakwaters as garbage bins: Structural complexity enhances anthropogenic litter accumulation in marine intertidal habitats.
Aguilera, M., Broitman, B., & Thiel, M.
Coastal urban infrastructures are proliferating across the world, but knowledge about their emergent impacts is still limited. Here, we provide evidence that urban artificial reefs have a high potential to accumulate the diverse forms of litter originating from anthropogenic activities around cities. We test the hypothesis that the structural complexity of urban breakwaters, when compared with adjacent natural rocky intertidal habitats, is a driver of anthropogenic litter accumulation. We determined litter abundances at seven sites (cities) and estimated the structural complexity in both urban breakwaters and adjacent natural habitats from northern to central Chile, spanning a latitudinal gradient of ∼15° (18°S to 33°S). Anthropogenic litter density was significantly higher in coastal breakwaters when compared to natural habitats (∼15.1 items m−2 on artificial reefs versus 7.4 items m−2 in natural habitats) at all study sites, a pattern that was temporally persistent. Different litter categories were more abundant on the artificial reefs than in natural habitats, with local human population density and breakwater extension contributing to increase the probabilities of litter occurrence by ∼10%. In addition, structural complexity was about two-fold higher on artificial reefs, with anthropogenic litter density being highest at intermediate levels of structural complexity. Therefore, the spatial structure characteristic of artificial reefs seems to enhance anthropogenic litter accumulation, also leading to higher residence time and degradation potential. Our study highlights the interaction between coastal urban habitat modification by establishment of artificial reefs, and pollution. This emergent phenomenon is an important issue to be considered in future management plans and the engineering of coastal ecosystems.
Año: 2016
Palabras claves: Artificial reefs; Anthropogenic litter; Rocky intertidal; Structural complexity; Shoreline.
Referencia APA: Aguilera, M., Broitman, B., & Thiel, M. (2016). Artificial breakwaters as garbage bins: Structural complexity enhances anthropogenic litter accumulation in marine intertidal habitats. Environmental Pollution, 214, 737-747.
Hydrologic Landscape Characterization for the Pacific Northwest, USA.
Leibowitz, S., Comeleo, R., Wigington, P., Weber, M., Sproles, E., & Sawicz, K.
We update the Wigington et al. (2013) hydrologic landscape (HL) approach to make it more broadly applicable and apply the revised approach to the Pacific Northwest (PNW; i.e., Oregon, Washington, and Idaho). Specific changes incorporated are the use of assessment units based on National Hydrography Dataset Plus V2 catchments, a modified snowmelt model validated over a broader area, an aquifer permeability index that does not require preexisting aquifer permeability maps, and aquifer and soil permeability classes based on uniform criteria. Comparison of Oregon results for the revised and original approaches found fewer and larger assessment units, loss of summer seasonality, and changes in rankings and proportions of aquifer and soil permeability classes. Differences could be explained by three factors: an increased assessment unit size, a reduced number of permeability classes, and use of smaller cutoff values for the permeability classes. The distributions of the revised HLs in five groups of Oregon rivers were similar to the original HLs but less variable. The improvements reported here should allow the revised HL approach to be applied more often in situations requiring hydrologic classification and allow greater confidence in results. We also apply the map results to the development of hydrologic landscape regions.
Año: 2016
Palabras claves: Hydrologic classification; hydrologic cycle; watersheds; rivers/streams; runoff; geospatial analysis; National Hydrography Dataset, NHD; Pacific Northwest.
Referencia APA: Leibowitz, S., Comeleo, R., Wigington, P., Weber, M., Sproles, E., & Sawicz, K. (2016). Hydrologic Landscape Characterization for the Pacific Northwest, USA. JAWRA Journal Of The American Water Resources Association, 52(2), 473-493. 1688.12402
Climatic characteristics of the semi-arid Coquimbo Region in Chile.
Montecinos, S., Gutiérrez, J., López-Cortés, F., & López, D.
The climate of the Coquimbo Region, north-central Chile is driven by atmospheric, oceanic and orographic factors. The southeast Pacific anticyclone, the cold Humboldt Current and the rugged topography that characterize the zone, determine thermally induced wind regimes and the formation of low stratocumulus along the coastline. Low precipitation and high solar radiation cause important climatic altitudinal gradients, especially on temperature and humidity, thus different climatic areas can be identified in the region. We summarized the general climatic characteristics of the study area and analyzed meteorological data to understand the behavior of the environmental variables. We used mesoscale modeling to evaluate the spatial characteristics of the mean air temperature, humidity and wind. These atmospheric variables present a strong elevation gradient. The particular topographic characteristics of the region favor the development of a thermally induced wind regime, where land and sea breezes and valley winds are observed.
Año: 2016
Palabras claves: Atmospheric modeling; Semi-arid zones; Desert.
Referencia APA: Montecinos, S., Gutiérrez, J., López-Cortés, F., & López, D. (2016). Climatic characteristics of the semi-arid Coquimbo Region in Chile. Journal Of Arid Environments, 126, 7-11.
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.
Nurse effect and soil microorganisms are key to improve the establishment of native plants in a semiarid community.
Molina-Montenegro, M., Oses, R., Atala, C., Torres-Díaz, C., Bolados, G., & León-Lobos, P.
Facilitation by the nurse effect can occur through an amelioration of environmental stress. Plant-microorganism interaction, however, is another key facilitation mechanism of the nurse effect, but is by far the least documented. Here we tested if microclimatic mitigation and soil microorganisms isolated from the root-zone of the nurse shrub Porlieria chilensis can increase the establishment of other native plants in a semiarid community. We conducted field and greenhouse experiments to evaluate the direct and indirect effects of the presence of P. chilensis on the survival and growth of three native plants. In the field experiment, we compared the survival and growth of transplanted individuals beneath nurses and outside of them in pots filled with soil from both microsites (beneath and outside nurses). Finally, in the greenhouse experiment we grew native plants in soil taken from both microsites (below and outside nurses) and with and without soil microorganisms (sterilization process). We found a clear and significant nurse effect of P. chilensis on the tested species through of amelioration of climatic (air temperature, soil moisture, and solar radiation) and edaphic (nitrogen availability) conditions, increasing the performance of these native species. Moreover, performance and establishment were enhanced when soil was kept with microorganisms. Thus, nurse effect mediated by microclimatic amelioration, edaphic improvement and presence of soil microorganisms could be key mechanisms to increase the establishment of native plant species in semiarid communities of central Chile.
Año: 2016
Palabras claves: Nurse effect; Facilitation; Chile; Microorganisms; Symbiosis; Positive interactions.
Referencia APA: Oses, R., Atala, C., Torres-Díaz, C., Bolados, G., & León-Lobos, P. (2016). Nurse effect and soil microorganisms are key to improve the establishment of native plants in a semiarid community. Journal Of Arid Environments, 126, 54-61.
Molecular characterization of two ferritins of the scallop Argopecten purpuratus and gene expressions in association with early development, immune response and growth rate.
Coba de la Peña, T., Cárcamo, C., Díaz, M., Brokordt, K., & Winkler, F.
Ferritin is involved in several iron homoeostasis processes in molluscs. We characterized two ferritin homologues and their expression patterns in association with early development, growth rate and immune response in the scallop Argopecten purpuratus, a species of economic importance for Chile and Peru. Two ferritin subunits (Apfer1 and Apfer2) were cloned. Apfer1 cDNA is a 792 bp clone containing a 516 bp open reading frame (ORF) that corresponds to a novel ferritin subunit in A. purpuratus. Apfer2 cDNA is a 681 bp clone containing a 522 bp ORF that corresponds to a previously sequenced EST. A putative iron responsive element (IRE) was identified in the 5′-untranslated region of both genes. The deduced protein sequences of both cDNAs possessed the motifs and domains characteristic of functional ferritin subunits. Both genes showed differential expression patterns at tissue-specific and early development stage levels. Apfer1 expression level increased 40-fold along larval developmental stages, decreasing markedly after larval settlement. Apfer1 expression in mantle tissue was 2.8-fold higher in fast-growing than in slow-growing scallops. Apfer1 increased 8-fold in haemocytes 24 h post-challenge with the bacterium Vibrio splendidus. Apfer2 expression did not differ between fast- and slow-growing scallops or in response to bacterial challenge. These results suggest that Apfer1 and Apfer2 may be involved in iron storage, larval development and shell formation. Apfer1 expression may additionally be involved in immune response against bacterial infections and also in growth; and thus would be a potential marker for immune capacity and for fast growth in A. purpuratus.
Año: 2016
Palabras claves: Ferritin; Argopecten purpuratus; Iron homoeostasis; Growth; Development; Immunity, Apfer1, Apfer2.
Referencia APA: Coba de la Peña, T., Cárcamo, C., Díaz, M., Brokordt, K., & Winkler, F. (2016). Molecular characterization of two ferritins of the scallop Argopecten purpuratus and gene expressions in association with early development, immune response and growth rate. Comparative Biochemistry And Physiology Part B: Biochemistry And Molecular Biology, 198, 46-56.
Developing a Snowmelt Forecast Model in the Absence of Field Data.
Sproles, E., Kerr, T., Orrego Nelson, C., & Lopez Aspe, D.
In data poor regions predicting water availability is a considerable challenge for water resource managers. In snow-dominated watersheds with minimal in situ measurements, satellite imagery can supplement sparse data networks to predict future water availability. This technical note presents the first phase of an operational forecast model in the data poor Elqui River watershed located in northern Central Chile (30°S). The approach applies remotely-sensed snow cover products from the Moderate Resolution Imaging Spectrometer (MODIS) instrument as the first order hydrologic input for a modified Snowmelt Runoff Model. In the semi-arid Elqui River, snow and glacier melt are the dominant hydrologic inputs but precipitation is limited to up to six winter events annually. Unfortunately winter access to the Andean Cordillera where snow accumulates is incredibly challenging, and thus measurements of snowpack are extremely sparse. While a high elevation snow monitoring network is under development, management decisions regarding water resources cannot wait as the region is in its eighth consecutive year of drought. Our model applies a Monte Carlo approach on monthly data to determine relationships between lagged changes in snow covered area and previous streamflow to predict subsequent streamflow. Despite the limited data inputs the model performs well with a Nash-Sutcliffe Efficiency and R2 of 0.830 and 0.833 respectively. This model is not watershed specific and is applicable in other regions where snow dominates hydrologic inputs, but measurements are minimal.
Año: 2016
Palabras claves: Snowmelt runoff, Hydrological model, Remote sensing, Hydrological prediction.
Referencia APA: Sproles, E., Kerr, T., Orrego Nelson, C., & Lopez Aspe, D. (2016). Developing a Snowmelt Forecast Model in the Absence of Field Data. Water Resour Manage, 30(7), 2581-2590.
Terral de Vicuña, a Foehnlike Wind in Semiarid Northern Chile: Meteorological Aspects and Implications for the Fulfillment of Chill Requirements in Deciduous Fruit Trees.
Montes, C., Rutllant, J., Aguirre, A., Bascuñán-Godoy, L., & Juliá, C.
The terral de Vicuña is a warm and dry wind that flows down the Elqui Valley in north-central Chile typically at dawn and early morning. Given that most terral episodes occur in austral winter when chill accumulation by deciduous fruit trees proceeds, negative effects on agriculture may be expected. During 11 (2004–14) winters a meteorological characterization of terral winds and the assessment of their impact on chill accumulation, by the modified Utah Model and the Dynamic Model, were performed. Within this period, 67 terral days (TD) were identified as those in which nighttime to early morning wind direction and speed, air temperature, and relative humidity reached defined thresholds on an hourly basis (terral hours). Most frequent TD featured 6–9 consecutive terral hours; duration is considered here as a proxy for their intensity. Synoptic-scale meteorological analysis shows that 65% of moderate and strong terral events develop as a cold, migratory anticyclone drifts poleward of the study area, coinciding with the onset of a midtropospheric ridge over central Chile, bringing southwest winds on top of the Andes (~500-hPa level). The remaining 35% are either associated with 500-hPa easterlies (foehn like), with prefrontal conditions ahead of a trough driving northwest 500-hPa winds, or with transitional 500-hPa westerlies. Assessments of chill accumulation during TD show that, although present average and cold winter conditions do not represent a major TD hazard to local agriculture, lower chill accumulation associated with anomalously high nocturnal temperatures could be significantly more important during present and future warmer winters.
Año: 2016
Palabras claves: South America; Downslope winds; Regional effects; Ecological models; Agriculture.
Referencia APA: Montes, C., Rutllant, J., Aguirre, A., Bascuñán-Godoy, L., & Juliá, C. (2016). Terral de Vicuña, a Foehnlike Wind in Semiarid Northern Chile: Meteorological Aspects and Implications for the Fulfillment of Chill Requirements in Deciduous Fruit Trees. J. Appl. Meteor. Climatol., 55(5), 1183-1196.
Climate variability and human impact in South America during the last 2000 years: synthesis and perspectives from pollen records.
Flantua, S., Hooghiemstra, H., Vuille, M., Behling, H., Carson, J., & Gosling, W., Hoyos, I., Ledru, M.P., Montoya, E., Mayle, F., Maldonado, A. et al.
An improved understanding of present-day climate variability and change relies on high-quality data sets from the past 2 millennia. Global efforts to model regional climate modes are in the process of being validated against, and integrated with, records of past vegetation change. For South America, however, the full potential of vegetation records for evaluating and improving climate models has hitherto not been sufficiently acknowledged due to an absence of information on the spatial and temporal coverage of study sites. This paper therefore serves as a guide to high-quality pollen records that capture environmental variability during the last 2 millennia. We identify 60 vegetation (pollen) records from across South America which satisfy geochronological requirements set out for climate modelling, and we discuss their sensitivity to the spatial signature of climate modes throughout the continent. Diverse patterns of vegetation response to climate change are observed, with more similar patterns of change in the lowlands and varying intensity and direction of responses in the highlands. Pollen records display local-scale responses to climate modes; thus, it is necessary to understand how vegetation–climate interactions might diverge under variable settings. We provide a qualitative translation from pollen metrics to climate variables. Additionally, pollen is an excellent indicator of human impact through time. We discuss evidence for human land use in pollen records and provide an overview considered useful for archaeological hypothesis testing and important in distinguishing natural from anthropogenically driven vegetation change. We stress the need for the palynological community to be more familiar with climate variability patterns to correctly attribute the potential causes of observed vegetation dynamics. This manuscript forms part of the wider LOng-Term multi-proxy climate REconstructions and Dynamics in South America – 2k initiative that provides the ideal framework for the integration of the various palaeoclimatic subdisciplines and palaeo-science, thereby jump-starting and fostering multidisciplinary research into environmental change on centennial and millennial timescales.
Año: 2016
Palabras claves:
Referencia APA: Flantua, S., Hooghiemstra, H., Vuille, M., Behling, H., Carson, J., & Gosling, W., Hoyos, I., Ledru, M.P., Montoya, E., Mayle, F., Maldonado, A. et al. (2016). Climate variability and human impact in South America during the last 2000 years: synthesis and perspectives from pollen records. Climate Of The Past, 12(2), 483-523.
Seasonal evolution of penitente glaciochemistry at Tapado Glacier, Northern Chile.
Sinclair, K. & MacDonell, S.
This study uses stable isotopes and major ions to examine the seasonal evolution of penitentes on the surface of Tapado Glacier, in the Norte Chico region of the Chilean Andes. A snow pit was sampled in November 2011, and penitentes were sampled during the summer (December 2011 and January 2012). The major ion load of the winter snowpack is dominated by Ca2+ (60%), SO42− (16%) and NO3− (13%), and there is little influence from marine air masses at the site, with most SO42−, Mg2+, Ca2+ and Na+, derived from non-sea salt sources. During the early ablation season we observe increases in stable isotope ratios and major ion concentrations (particularly lithic ions Na+, Mg2+ and Ca2+) in the upper reaches of penitentes, which is attributed to sublimation and the aeolian deposition of dust particles. In the late-summer, melt replaces sublimation as the dominant ablation process and results in smoothing of the stable isotope profile and the elution of major ions within the penitente snow and ice matrix. Copyright © 2015 John Wiley & Sons, Ltd.
Año: 2016
Palabras claves: Abiotic stress, adaptation, Andean crop, genetic variability, halophyte crop, nutritional properties, salinity.
Referencia APA: Sinclair, K. & MacDonell, S. (2016). Seasonal evolution of penitente glaciochemistry at Tapado Glacier, Northern Chile. Hydrol. Process., 30(2), 176-186.
Variability of 14C reservoir age and air–sea flux of CO2 in the Peru–Chile upwelling region during the past 12,000years.
Carré, M., Jackson, D., Maldonado, A., Chase, B., & Sachs, J.
The variability of radiocarbon marine reservoir age through time and space limits the accuracy of chronologies in marine paleo-environmental archives. We report here new radiocarbon reservoir ages (ΔR) from the central coast of Chile (~ 32°S) for the Holocene period and compare these values to existing reservoir age reconstructions from southern Peru and northern Chile. Late Holocene ΔR values show little variability from central Chile to Peru. Prior to 6000 cal yr BP, however, ΔR values were markedly increased in southern Peru and northern Chile, while similar or slightly lower-than-modern ΔR values were observed in central Chile. This extended dataset suggests that the early Holocene was characterized by a substantial increase in the latitudinal gradient of marine reservoir age between central and northern Chile. This change in the marine reservoir ages indicates that the early Holocene air–sea flux of CO2 could have been up to five times more intense than in the late Holocene in the Peruvian upwelling, while slightly reduced in central Chile. Our results show that oceanic circulation changes in the Humboldt system during the Holocene have substantially modified the air–sea carbon flux in this region.
Año: 2016
Palabras claves: Humboldt system; Reservoir age; Shell middens; Deglaciation; Radiocarbon; CO2.
Referencia APA: Carré, M., Jackson, D., Maldonado, A., Chase, B., & Sachs, J. (2016). Variability of 14C reservoir age and air–sea flux of CO2 in the Peru–Chile upwelling region during the past 12,000years. Quaternary Research, 85(1), 87-93.
Quinoa – a Model Crop for Understanding Salt-tolerance Mechanisms in Halophytes.
Ruiz, K., Biondi, S., Martínez, E., Orsini, F., Antognoni, F., & Jacobsen, S.
Quinoa (Chenopodium quinoa Willd.) is an ancient Andean crop that produces edible seeds and leaves. Quinoa's tolerance to salinity and other types of abiotic stresses provides it with high potential in a world where scarcity of water and increased soil salinization are important causes of crop failures. Due to its traditionally broad cultivation area (from Colombia to southern Chile), there is a wide range of quinoa cultivars adapted to specific conditions displaying a broad genetic variability in stress tolerance. In addition, being practically unique as a halophytic seed-producing crop with amazing nutritional properties, it is ideal as a model species for investigating morphological, cellular, physiological, and bio-molecular mechanisms of salinity tolerance. This review summarizes current knowledge of genotype-dependent variability in salinity responses and adaptive salt-tolerance mechanisms in quinoa. These include anatomical features and physiological aspects, such as osmotic adjustment through accumulation of ions, osmoprotectants, and sodium loading, transport, and storage, including the activity and gene expression of plasma and vacuolar membrane transporters. Finally, current knowledge regarding the effect of salinity on the nutritional properties of quinoa is discussed.
Año: 2016
Palabras claves: Abiotic stress, adaptation, Andean crop, genetic variability, halophyte crop, nutritional properties, salinity.
Referencia APA: Ruiz, K., Biondi, S., Martínez, E., Orsini, F., Antognoni, F., & Jacobsen, S. (2016). Quinoa – a Model Crop for Understanding Salt-tolerance Mechanisms in Halophytes. Plant Biosystems - An International Journal Dealing With All Aspects Of Plant Biology, 150(2), 357-371.