CEAZA
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.
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.
Updated site compilation of the Latin American Pollen Database
Flantua, S., Hooghiemstra, H., Grimm, E., Behling, H., Bush, M., & González-Arango, C., Gosling, W.D., Ledru, M.P., Lozano-García, S., Maldonado, A., Prieto, A.R., Rull, V., Van Boxel, J.H.
The updated inventory of the Latin American Pollen Database (LAPD) offers a wide range of new insights. This paper presents a systematic compilation of palynological research in Latin America. A comprehensive inventory of publications in peer-reviewed and grey literature shows a major expansion of studies over the last decades. The inventory includes 1379 cores and sections with paleoecological data and more than 4800 modern samples from throughout the continent. Through the years, pollen datasets extend over increasing spans of time and show improved taxonomic and temporal resolution. Currently, these datasets are from 12 modern biomes and 30 countries, covering an altitudinal range of 0 to 6300 m asl. The most densely sampled regions are the Colombian Andes, the southeast coast of Brazil, and Patagonia. Underrepresented biomes are the warm temperate mixed forest (3%), dry forests (3%), and warm temperate rainforest (1%); whereas steppe, tropical rainforest, and cool grass shrublands, such as the páramos, are generally well represented (all > 17%). There are 126 records that span the late Pleistocene to the Last Glacial Maximum transition (21,000 cal yr BP), and > 20% of the records cover the Younger Dryas interval and the Pleistocene/Holocene transition. Reanalysis of numerous sites using multiproxy tools emphasize the informative value of this approach in paleoenvironmental reconstruction. We make suggestions for several pollen sites and regions to be visited again; similarly we identify some key research questions that have yet to be answered. The updated LAPD now provides the platform to support an exciting new phase of global palynological research in which multi-site data are being integrated to address current cutting-edge research questions. The LAPD compilation of sites and the literature database will be available through the Neotoma Paleoecology Database website and a new LAPD website by the end of 2015.
Año: 2015
Palabras claves: Pollen analysis; Latin America; Site distribution patterns; Age control density; Publication history; LAPD.
Referencia APA: Flantua, S., Hooghiemstra, H., Grimm, E., Behling, H., Bush, M., & González-Arango, C., Gosling, W.D., Ledru, M.P., Lozano-García, S., Maldonado, A., Prieto, A.R., Rull, V., Van Boxel, J.H. (2015). Updated site compilation of the Latin American Pollen Database. Review Of Palaeobotany And Palynology, 223, 104-115.
Comparison of DNA extraction methods for polymerase chain reaction amplification of guanaco (Lama guanicoe) fecal DNA samples.
Espinosa, M., Bertin, A., Squeo, F., Cortés, A., & Gouin, N.
Feces-based population genetic studies have become increasingly popular. However, polymerase chain reaction (PCR) amplification rates from fecal material vary depending on the species, populations, loci, and extraction protocols. Here, we assessed the PCR amplification success of three microsatellite markers and a segment of the mitochondrial control region of DNA extracted from field-collected feces of guanaco (Lama guanicoe) using two protocols - Qiagen DNA Stool Kit and 2 cetyltrimethylammonium bromide/phenol:chloroform:isoamyl alcohol (2CTAB/PCI) method. Chelex resin treatment to remove inhibitors was also tested. Our results show that the mitochondrial locus was the most difficult to amplify. PCR success rates
improved for all markers after Chelex treatment of extracted DNA, and 2CTAB/PCI method (95.83%) appeared to perform slightly better than stool kit (91.67%) for the nuclear markers. Amplification success was significantly influenced by the extraction method, Chelex treatment, and locus (P < 0.001) but not by the freshness of the feces (fresh vs old, P = 0.17). The repeatability levels were high without Chelex treatment (> 0.89), but they decreased slightly after treatment for amplification of nuclear markers and markedly after treatment for amplification of the mitochondrial control region. Thus, we showed that Chelex treatment gives high PCR success, especially for nuclear markers, and adequate DNA extraction rates can be achieved from L. guanicoe feces even from non-fresh fecal material. Although not significant, 2CTAB/PCI method tended to provide higher successful amplification rates on a whole set of samples, suggesting that the method could be particularly useful when using small sample sizes.
Año: 2015
Palabras claves: Non-invasive genetics; Mitochondrial control region;Microsatellites; Polymerase chain reaction inhibitors;Chelex treatment; Lama guanicoe.
Referencia APA: Espinosa, M., Bertin, A., Squeo, F., Cortés, A., & Gouin, N. (2015). Comparison of DNA extraction methods for polymerase chain reaction amplification of guanaco (Lama guanicoe) fecal DNA samples. Genetics And Molecular Research, 14(1), 400-406.
Changes of heritability and genetic correlations in production traits over time in red abalone ( Haliotis rufescens ) under culture.
Brokordt, K., Winkler, F., Farías, W., González, R., Castaño, F., Fullsack, P., & Herbinger, C.
Red abalone Haliotis rufescens is one of the most valuable mollusks in the international market, but it has a low growth rate. A breeding program is being developed to increase its growth rate in Chile. We estimated the changes in direct heritability (h2), maternal/common environments heritability (m2) and genetic correlations (rG) of growth traits (shell length and width, total mass, flesh mass and foot protein as an indicator of meat quality) measured during 2 years (every 4 months) from the juvenile stage (27 months) to the adult harvesting age (51 months), in 60 full-sib red abalone families. Heritabilities for growth traits measured in juveniles and young adults (27–35 months of age), were low (0.07–0.17) and not significant. Initial low h2 were associated with significant amounts of maternal/common environmental effects (m2 = 0.4). In young adults and abalone near the harvest age (39–51 months of age) h2 were much higher (0.32–0.75). These results emphasize the importance of multiple estimations of h2 over time. Among meat quality traits, only the h2 for the flesh mass for adults at harvesting age was significant (0.15). We observed strong positive rG (>0.9) between shell sizes (easy to measure) and total and flesh masses (trait more related to market value than shell sizes but harder to measure) for adults at harvesting age. Thus, if the 5% largest 51 month old abalone were selected from the population as broodstock we expect a positively correlated response on flesh mass of 23.4%.
Año: 2015
Palabras claves: Abalone aquaculture; heritability; maternal effects; growth; genetic improvement; Haliotis rufescens.
Referencia APA: Brokordt, K., Winkler, F., Farías, W., González, R., Castaño, F., Fullsack, P., & Herbinger, C. (2015). Changes of heritability and genetic correlations in production traits over time in red abalone (Haliotis rufescens) under culture. Aquaculture Research, 46(9), 2248-2259.
Mitochondrial DNA diversity of feral pigs from Karukinka Natural Park, Tierra del Fuego Island, Chile.
Aravena, P., Skewes, O., & Gouin, N.
: Control or eradication of exotic species is one of the greatest challenges facing biodiversity and ecosystem conservation. Domestic pigs (Sus scrofa domestica) were released and became feral in the southern region of Chilean Tierra del Fuego Island in the 1900s.
Currently, they inhabit part of Karukinka Natural Park, an area of global conservation concern. To gain insight into the control of this invasive species, we analyzed genetic variation in the mitochondrial DNA control region to determine the origin and population subdivision of feral pigs in Tierra del Fuego. Sequences from a sample of 42 feral pigs, 10 domestic pigs from local farms, and references from other countries and commercial breeds revealed 2 highly differentiated populations,
1 in the western and the other in the eastern area of the park, each harboring a different haplotype, suggesting no connectivity between populations. Comparison of these haplotypes with reference sequences from other countries and commercial breeds indicated that feral pigs from Chilean Tierra del Fuego are of European origin, very likely from
2 separate introduction events. The haplotype found in the western feral population was also identified in domestic pigs from a farm. This raises concerns regarding the possible connectivity between stocks from local farms and the wild population. Based on these results, we recommend the development of strategies for controlling the population of this invasive species in Karukinka Natural Park.
Año: 2015
Palabras claves: Feral pigs; Invasive species; mtDNA control region;Sus scrofa; Tierra del Fuego Island.
Referencia APA: Aravena, P., Skewes, O., & Gouin, N. (2015). Mitochondrial DNA diversity of feral pigs from Karukinka Natural Park, Tierra del Fuego Island, Chile. Genetics And Molecular Research, 14(2), 4245-4257.
Tefrocronología en curso superior del valle del río Cisne (44°S), Chile Austral.
Stern, C., De Porras, M., & Maldonado, A.
Based on their petrography and chemistry, 18 tephra analyzed from two lake and bog cores and one outcrop in the upper Río Cisnes valley are believed to have been derived from nine different eruptions of the Mentolat volcano, four of the Melimoyu volcano, and one from the Hudson volcano. Some of these tephra correlate chronologically and petrochemically with previously documented large eruptions of these volcanoes, including the Late-Glacial Ho eruption of Hudson (17,340 cal yrs BP), the mid-Holocene MEN1 eruption of Mentolat (7,710 cal yrs BP), and the Late-Holocene MEL2 eruption of Melimoyu (1,680 cal yrs BP). A Melimoyu-derived tephra from the outcrop occurs in glacial-lacustrine sediments and is considered to pre-date the Last Glacial Maximum (>19,670 cal yrs BP). The data suggest that none of the tephra were produced by explosive eruptions of the Maca, Cay and Yanteles volcanoes.
Año: 2015
Palabras claves: Tephra, Tephrochronology, Tephrostratigraphy, Volcanism, Andes, Chile.
Referencia APA: Stern, C., De Porras, M., & Maldonado, A. (2015). Tefrocronología en curso superior del valle del río Cisne (44°S), Chile Austral. Andean Geology, 42(2).
Detecting Subtle Seasonal Transitions of Upwelling in North-Central Chile.
Rahn, D., Rosenblüth*, B., & Rutllant, J.
Biological productivity in the ocean along the Chilean coast is tied to upwelling that is primarily forced by equatorward wind stress and wind stress curl on the ocean surface. Southerly alongshore flow is driven by the southeast Pacific (SEP) anticyclone, and its intensity and position vary on a range of time scales. Variability of the SEP anticyclone has been linked to large-scale circulations such as El Niño–Southern Oscillation and the Madden–Julian oscillation. The actual timing, duration, and nature of the seasonal meridional drift of the SEP anticyclone are associated with the onset, demise, and strength of the local upwelling season. Seasonal variation is especially marked at the Punta Lavapié (37°S) upwelling focus, where there is a clear upwelling season associated with a change of the cumulative upwelling index (CUI) slope between positive and negative. The Punta Lengua de Vaca (30°S) focus typically exhibits upwelling year-round and has less distinct transitions, making it more difficult to identify an enhanced upwelling season. A two-phase linear regression model, which is typically used to detect subtle climate changes, is applied here to detect seasonal changes in CUI at Punta Lengua de Vaca. This method objectively finds distinct transitions for most years. The spring-to-summer transition is more readily detected and the slackening of the upwelling-favorable winds, warmer waters, and longer wind strengthening–relaxation cycles change the coastal upwelling ecosystem. While the spring-to-summer transition at Punta Lengua de Vaca could be influenced by large-scale circulations, the actual dates of transition are highly variable and do not show a clear relationship.
Año: 2015
Palabras claves: Circulation/ Dynamics; Upwelling/downwelling; Atm/Ocean Structure/ Phenomena; Madden-Julian oscillation; Physical Meteorology and Climatology; Climate variability; Coastal meteorology; ENSO.
Referencia APA: Rahn, D., Rosenblüth*, B., & Rutllant, J. (2015). Detecting Subtle Seasonal Transitions of Upwelling in North-Central Chile. J. Phys. Oceanogr., 45(3), 854-867.
Potential Response to Selection of HSP70 as a Component of Innate Immunity in the Abalone Haliotis rufescens.
Brokordt, K., González, R., Farías, W., & Winkler, F.
Assessing components of the immune system may reflect disease resistance. In some invertebrates, heat shock proteins (HSPs) are immune effectors and have been described as potent activators of the innate immune response. Several diseases have become a threat to abalone farming worldwide; therefore, increasing disease resistance is considered to be a long-term goal for breeding programs. A trait will respond to selection only if it is determined partially by additive genetic variation. The aim of this study was to estimate the heritability (h2) and the additive genetic coefficient of variation (CVA) of HSP70 as a component of innate immunity of the abalone Haliotis rufescens, in order to assess its potential response to selection. These genetic components were estimated for the variations in the intracellular (in haemocytes) and extracellular (serum) protein levels of HSP70 in response to an immunostimulant agent in 60 full-sib families of H. rufescens. Levels of HSP70 were measured twice in the same individuals, first when they were young and again when they were pre-harvest adults, to estimate the repeatability (R), the h2 and the potential response to selection of these traits at these life stages. High HSP70 levels were observed in abalones subjected to immunostimulation in both the intracellular and extracellular haemolymph fractions. This is the first time that changes in serum levels of HSP70 have been reported in response to an immune challenge in molluscs. HSP70 levels in both fractions and at both ages showed low h2 and R, with values that were not significantly different from zero. However, HSP70 induced levels had a CVA of 13.3–16.2% in young adults and of 2.7–8.1% in pre-harvest adults. Thus, despite its low h2, HSP70 synthesis in response to an immune challenge in red abalone has the potential to evolve through selection because of its large phenotypic variation and the presence of additive genetic variance, especially in young animals.
Año: 2015
Palabras claves: Heat shock response, Immune response, Genetic polymorphism, Phenotypes, Young adults, Immune system proteins, Invertebrates, Crop genetics.
Referencia APA: Brokordt, K., González, R., Farías, W., & Winkler, F. (2015). Potential Response to Selection of HSP70 as a Component of Innate Immunity in the Abalone Haliotis rufescens. PLOS ONE, 10(11), e0141959.
Aeolian particles in marine cores as a tool for quantitative high-resolution reconstruction of upwelling favorable winds along coastal Atacama Desert, Northern Chile.
Flores-Aqueveque, V., Alfaro, S., Vargas, G., Rutllant, J., & Caquineau, S.
Upwelling areas play a major role in ocean biogeochemical cycles and ultimately in global climate, especially in higly productive regions as the South Eastern Pacific. This work is based on the analysis of the aeolian lithic particles accumulated in laminated sediments off Mejillones (23°S) in the eastern boundary Humboldt Current System. It proposes a high-resolution quantitative reconstruction of the upwelling-favorable southerly wind strength in the past ∼250 years, comparing its variability with changes in organic carbon export/preserved changes to the sea bottom. The increase of the intensity and variability in fluxes of particles larger than 35 μm and 100 μm since the second half of the 19th century and during the 20th century confirms a general strengthening of southerly winds in the region. Spectral analysis on the complete time-series of yearly depositional fluxes indicates that sedimentary variability can be explained by a combination of interannual (ENSO) to decadal (PDO) oscillations similar to the ones yielded by the analysis of the Interdecadal Pacific Oscillation index. However, when applied separately to the lithic fluxes of the first and last centuries of the time-series, the method shows that relative to the one of the interannual mode of variability, the influence of the decadal mode has increased in the recent period.
Based on the presence/absence of particles with sizes larger than 35/100 μm, each year of the time series is classified as a ‘Low wind’ (<6 m/s), ‘Intermediate wind’ (6–8 m/s), or ‘Strong wind’ (10 to >12 m/s) year. From the AD 1754–1820 period to the AD 1878–1998 one, the proportion of Low and Intermediate wind years decreased from 12% and 74% to 3% and 68%, respectively, whereas the proportion of strong wind years increased from 14% to 29%. For these periods the mean organic carbon also increased 22%, stating the strong relation between export/preservation productivity rate and southerly wind intensity.
In the recent period (from AD 1950 on) for which the Oceanic Niño Index is available, the strong wind years (AD 1982, 1983, 1994, and 1997) correspond to large values of this index, suggesting that constructive interferences that result from the interplay between interannual and decadal oscillations modes might explain in part the reinforcement of the winds along the North Chilean coast.
Año: 2015
Palabras claves:
Referencia APA: Flores-Aqueveque, V., Alfaro, S., Vargas, G., Rutllant, J., & Caquineau, S. (2015). Aeolian particles in marine cores as a tool for quantitative high-resolution reconstruction of upwelling favorable winds along coastal Atacama Desert, Northern Chile. Progress In Oceanography, 134, 244-255.