CEAZA
The response of leaf respiration to water stress in Nothofagus species.
Sanhueza, C., Bascunan-Godoy, L., Corcuera, L., & Turnbull, M.
Nothofagus solandri is regarded as more tolerant to drought than Nothofagus menziesii in the field. However, the physiology of responses to water limitation in these species is not well understood. In this study, the thermal sensitivity of leaf respiration and its underlying metabolism in response to drought were investigated in mature trees and saplings. Respiration (R d) and photosynthesis (A max) were measured during drying and re-wetting cycles. In addition, respiratory pathway changes were evaluated by oxygen isotope fractionation and protein analyses. Under drought treatment in the glasshouse, both species showed similar photosynthetic performance, but under mild water stress N. solandri was able to increase A max. Under moderate water deficit (around −2 MPa), N. solandri increased respiration at a base temperature of 10°C (R 10) but then decreased it to initial values after re-watering. In N. menziesii, R 10 did not respond significantly to water-stress treatment. The temperature sensitivity of R d (Q 10 and E o) was unchanged for both species during the gradual deficit water treatment in the glasshouse. Although respiratory electron flow was mainly via the cytochrome pathway under all conditions, an increase in alternative oxidase/cytochrome oxidase protein content suggests that the alternative pathway is involved in modulating respiratory metabolism during the recovery after drought.
Año: 2013
Palabras claves: Alternative oxidase, cytochrome oxidase, drought, metabolism, New Zealand, trees.
Referencia APA: Sanhueza, C., Bascunan-Godoy, L., Corcuera, L., & Turnbull, M. (2013). The response of leaf respiration to water stress in Nothofagus species. New Zealand Journal Of Botany, 51(2), 88-103.
Analysis of benthic macroinvertebrates and biotic indices to evaluate water quality in rivers impacted by mining activities in northern Chile.
Alvial, I., Tapia, D., Castro, M., Duran, B., & Verdugo, C.
Catchments in the semiarid regions are especially susceptible to environmental perturbation associated with water scarcity, hydrological variations and overuse by anthropogenic activities. Using multivariate analysis to relate environmental and biological data, and diversity and biotic indices (ChBMWP, ChIBF), we analyzed the macroinvertebrate composition of 12 rivers of the semiarid region of northern Chile. A non-metric multidimensional scaling for macroinvertebrate taxa and a principal component analysis for environmental variables strongly separated upstream sites (e.g. Vacas Heladas and Malo Rivers), which presented low pH and high dissolved metal concentrations, from other sites. Effectively, CCA showed that metals and low pH, associated with the altitudinal gradient, determined the distributional patterns of macroinvertebrates in the Elqui catchment. The causes of these particular conditions could be related to geological processes and human impact. The biotic indices applied to the sampling sites corroborated and reflected these characteristics, with La Laguna and Turbio Rivers showing a diverse macroinvertebrate community and moderate to good water quality, and the Claro River showing favorable conditions for the development of aquatic biota, indicating its better quality relative to other stations. To the middle and low part of the basin, a change in the composition of the community was observed, with species that suggest an impact by an increase in organic matter, due to agricultural activities and urban settlements concentrated in this area. Our results suggest that macroinvertebrate taxa in northern Chile may be exceptional species, adapted to unfavorable geochemical conditions, and emphasize the need for protection of the semiarid basins of the region.
Año: 2013
Palabras claves: macro-invertebrates / biotic indices / multivariate analysis / semiarid region
Referencia APA: Alvial, I., Tapia, D., Castro, M., Duran, B., & Verdugo, C. (2013). Analysis of benthic macroinvertebrates and biotic indices to evaluate water quality in rivers impacted by mining activities in northern Chile. Knowledge And Management Of Aquatic Ecosystems, (407), 01.
Meteorological observations on the northern Chilean coast during VOCALS-REx.
Rutllant, J., Muñoz, R., & Garreaud, R.
Surface coastal observations from two automatic weather stations at Paposo (~25° S) and radiosonde observations at Paposo and Iquique (~20° S) were carried out during VOCALS-REx (VAMOS Ocean-Cloud-Atmosphere-Land Study Regional Experiment). Within the coastal marine boundary layer (MBL), sea–land breezes are superimposed on the prevailing southerlies, resulting in light northeasterly winds from midnight to early morning and strong southwesterlies in the afternoon. The prevailing northerlies above the MBL and below the top of the Andes are modulated by the onshore-offshore (zonal) flow forced by the diurnal cycle of surface heating/cooling along the western slope of the Andes. The daytime phase of this diurnal cycle is consistent with an enhanced afternoon coastal subsidence manifested in afternoon warming near the top of the subsidence inversion (~1.8 K at 800 hPa), lowering (~130 m) of its base (top of the MBL), and clearing of coastal Sc (stratocumulus) clouds. Results from a numerical simulation of the atmospheric circulation in a mean zonal cross section over the study area capture the afternoon zonal wind divergence and resulting subsidence of about 2 cm s−1 along a narrow (~10 km) coastal strip maximizing at around 800 hPa. Day-to-day variability in the MBL depth during VOCALS-REx shows sub-synoptic oscillations, aside from two major disruptions in connection with a deep trough and a cutoff low, as described elsewhere. These oscillations are phase-locked to those in sea-level pressure and afternoon alongshore southerlies, as found in connection with coastal lows farther south.
From 24-h forward trajectories issued from significant points at the coast and inland at the extremes of the diurnal cycle, it can be concluded that the strong mean daytime Andean pumping prevents any possibility of continental sulfur sources from reaching the free troposphere above the Sc cloud deck in at least a one-day timescale, under mean conditions. Conversely, coastal sources could contribute with sulfur aerosols preferentially in the morning, provided that the weak daytime inland flow becomes partially blocked by the coastal terrain.
Año: 2013
Palabras claves:
Referencia APA: Rutllant, J., Muñoz, R., & Garreaud, R. (2013). Meteorological observations on the northern Chilean coast during VOCALS-REx. Atmospheric Chemistry And Physics, 13(6), 3409-3422.
Anthropogenic marine debris in the coastal environment: A multi-year comparison between coastal waters and local shores.
Thiel, M., Hinojosa, I., Miranda, L., Pantoja, J., Rivadeneira, M., & Vásquez, N.
Anthropogenic marine debris (AMD) is frequently studied on sandy beaches and occasionally in coastal waters, but links between these two environments have rarely been studied. High densities of AMD were found in coastal waters and on local shores of a large bay system in northern-central Chile. No seasonal pattern in AMD densities was found, but there was a trend of increasing densities over the entire study period. While plastics and Styrofoam were the most common types of AMD both on shores and in coastal waters, AMD composition differed slightly between the two environments. The results suggest that AMD from coastal waters are deposited on local shores, which over time accumulate all types of AMD. The types and the very low percentages of AMD with epibionts point to mostly local sources. Based on these results, it can be concluded that a reduction of AMD will require local solutions.
Año: 2013
Palabras claves: Anthropogenic marine debris; Local shores; Coastal waters; Plastics; SE Pacific.
Referencia APA: Thiel, M., Hinojosa, I., Miranda, L., Pantoja, J., Rivadeneira, M., & Vásquez, N. (2013). Anthropogenic marine debris in the coastal environment: A multi-year comparison between coastal waters and local shores. Marine Pollution Bulletin, 71(1-2), 307-316
Daidzein and Genistein contents in seeds of quinoa (Chenopodium quinoa Willd.) from local ecotypes grown in arid Chile.
Lutz, M., Martínez, A., & Martínez, E.
The contents of bioactive compounds of quinoa (Chenopodium quinoa Willd.) are poorly known. We analyzed two isoflavones (daidzein and genistein) by HPLC in three local ecotypes of quinoa seeds from three different geographical and genetic regions in Chile: (a) Extreme North, with prevailing conditions of high temperature and dryness (local ecotype R49); (b) Center, with milder climate (local ecotype UdeC9); and (c) South, with cold, humid environment (local ecotype BO78). Genetic-driven differences among cultivars were tested by homogenizing the culture conditions of the three seed sources. In addition, seven commercial samples of quinoa purchased at local food markets were analyzed and compared to our experimental harvested seeds. In all samples daidzein content was higher than genistein (P < 0.05). The northern ecotype R49 exhibited higher content of isoflavones compared with the other two (UdeC9 and BO78), all grown under the same experimental conditions. Daidzein ranged from 1.15 (R49) to 0.70 (BO78) mg/100 g, while genistein varied from 0.25 (R49) to 0.05 (UdeC9) mg/100 g. Ecotype R49 had 1.6 and 1.7 fold higher daidzein contents than UdeC9 and BO78, respectively (P < 0.05). In the commercial samples, the daidzein/genistein ratio ranged from 25.2 to 3.9, daidzein ranged from 2.05 to 0.78 mg/100 g, and genistein ranged from 0.41 to 0.04 mg/100 g. To the best of our knowledge, this is the first report on the contents of daidzein and genistein in quinoa seeds. The study demonstrates that, besides its well-recognized nutritional value, quinoa possesses an excellent potential as a source of these health-promoting bioactive compounds.
Año: 2013
Palabras claves: Quinoa; Daidzein; Genistein; Isoflavones; Ecotypes.
Referencia APA: Lutz, M., Martínez, A., & Martínez, E. (2013). Daidzein and Genistein contents in seeds of quinoa (Chenopodium quinoa Willd.) from local ecotypes grown in arid Chile. Industrial Crops And Products, 49, 117-121.
Importance of geochemical factors in determining distribution patterns of aquatic invertebrates in mountain streams south of the Atacama Desert, Chile.
Alvial, I., Orth, K., Durán, B., Álvarez, E., & Squeo, F.
The ecology of macroinvertebrate communities in arid regions is still poorly understood. Here we examined how the community structure varied at spatial and temporal scales in streams and tributaries of the Huasco River in semi-arid region of Northern Chile. We expected that macroinvertebrate distribution may be responding to natural processes of mineralization described for Chilean semiarid basins. The relationships among biotic and abiotic variables were assessed through multivariate techniques (principal component analysis, non-metric multidimensional scaling, canonical correspondence analysis), and a two-way analysis of similarity was used to evaluate differences between basins and years (2007, 2008, and 2009). Significant differences in community structure and physical–chemical variables between basins (Del Carmen and Del Tránsito) were found, but not between years. Altitude, Mn, Al, Ca, Na, HCO3, and dissolved oxygen were the variables that best accounted for the communities distribution. In particular, high metals concentration in El Transito basin should determine low density and diversity of macroinvertebrates. Chironomidae, Ephydridae, and Glossiphoniidae were associated to waters with high metals content and acidic pH, whereas Baetidae, Hydroptilidae, and Blephariceridae were associated to sites with more favorable physical–chemical conditions. These results contribute to understand the ecological patterns of macroinvertebrates in arid regions and should lead to conservation and monitoring plans for this remote place.
Año: 2013
Palabras claves: Huasco basin, Desert climate, Macroinvertebrates, Biomonitoring, Habitat variables, Handling editor: Koen Martens
Referencia APA: Alvial, I., Orth, K., Durán, B., Álvarez, E., & Squeo, F. (2013). Importance of geochemical factors in determining distribution patterns of aquatic invertebrates in mountain streams south of the Atacama Desert, Chile. Hydrobiologia, 709(1), 11-25.
Estimating Spatial Distribution of Air Temperature from Meteorological Stations Using Atmospheric Model.
Montecinos, S., Bascuñán-Godoy, L., Salinas, P., Astudillo, O., & Lopez, D.
Planning agricultural procedures needs to take into account meteorological conditions. However, because of high associated costs, the density of meteorological stations is often not enough to cover all the cultivated or potentially cultivated areas. In this article we present a methodology to estimate seasonal maximum and minimum mean temperature in cultivated area using data registered in a sole or a few meteorological stations. The procedure is based on mesoscale modeling, which allows meteorological variables to be spatially distributed considering synoptic data and local characteristics.
Simulated daily cycle of temperature was compared with data registered at six meteorological stations located in the cultivated floor of the semiarid Limari Valley (Chile, 31°S). Although in some cases the simulated temperature differs in about 2°C with the observed one, a good fit between model results and experimental data was observed. Using the simulated seasonal minimum and maximum mean temperature fields, maps of temperature differences with respect to a reference station were drawn. In order to observe the influence of the orography on the lapse rate around a station, the methodology was applied for two reference stations located in places with different orographic characteristics. Results for winter and summer seasons are shown.
These generated maps can be used by farmers and agricultural planners to obtain information of seasonal minimum and maximum mean temperature from a station in any site of the cultivated area. This technique is a good alternative to obtain meteorological information at low costs, contributing to territorial planning for climate resilient agriculture sustainability.
Año: 2013
Palabras claves:
Referencia APA: Montecinos, S., Bascuñán-Godoy, L., Salinas, P., Astudillo, O., & Lopez, D. (2013). Estimating Spatial Distribution of Air Temperature from Meteorological Stations Using Atmospheric Model. Journal Of Agricultural Science, 5(2).
Can a breakdown in competition-colonization tradeoffs help explain the success of exotic species in the California flora?
Molina-Montenegro, M., Cleland, E., Watts, S., & Broitman, B.
Determining combinations of functional traits that allow a species to colonize new habitats has been central in the development of invasion ecology. Species able to establish in new communities harbor abilities or traits that allow them to use resources or tolerate stress in ways that native species cannot. Tradeoffs among species functional traits along the competition–colonization (CC) continuum, where competitive ability is a decreasing function of dispersal capacity, may allow invasive species to establish themselves in new habitats. The California flora offers a well-characterized model system to examine whether native and exotic species differ in the distribution of functional traits and to examine whether a breakdown of the CC tradeoff is present. We used a random subset of 1000 plants and examined seed traits and life form characteristics along with their seed size and adult height using the Jepson Manual of the plants of California. To test the hypothesis that active dispersal strategies aid in the success of exotic species, we classified species into four seed types according to the presence/absence of mechanisms associated with efficient dispersal. In addition, for each species we compiled data on seed size and adult plant height. We conducted all comparisons between native and exotic species within the four most speciose families to control for potential taxonomic non-independence. Exotic species had smaller seed size but greater plant height than natives of the same families. On the other hand, exotic species also displayed significantly greater proportions of functional traits that enhanced dispersal ability. Additionally, certain sets of functional traits were significantly associated with exotic species, such as annual life histories with small seeds and high dispersal capacity. In the random subset of the California flora examined, exotics of the most speciose plant families show functional trait combinations that appear to violate the tradeoff structures observed in their California counterparts. Our results suggest that taxonomically controlled comparisons of the CC tradeoff structure between natives and exotic species may shed light of the capacity of those exotic species invasive ability to colonize new habitats.
Año: 2012
Palabras claves:
Referencia APA: Molina-Montenegro, M., Cleland, E., Watts, S., & Broitman, B. (2012). Can a breakdown in competition-colonization tradeoffs help explain the success of exotic species in the California flora?. Oikos, 121(3), 389-395.
Characterization of the interactions between subterranean and superficial fluxes within an Andean catchment as a function of the spatio- temporal variability of climate.
Jourde, H., Blanc, M., Rochette, R., Ruelland, D., Hicks, E., & Oyarzun, R
In the semi-arid region of Norte Chico (Chile), climate variability, mainly controlled by ENSO and LNSO events, generates a high variability of both surface water and groundwater fluxes. Taking the upper Elqui catchment as an example, this study found that, during LNSO events, the abnormally high values of the runoff coefficient may be the consequence of a groundwater contribution to surface water flow. During ENSO events, however, the lower values of the runoff coefficient and the dynamics of the water table level highlight the recharge of the subsurface compartment. For the hydrological years characterized by a high pluviometric index during the 1977–2008 period, three dynamics of interaction between groundwater and surface water are identified : (i) the water table increases before the river discharge, and its logarithmic increase highlights a rapid recharge related to the concomitance of snowmelt and rainfall events ; (ii) the water table increases after the river discharge and its exponential increase shows a progressive intensification of the recharge over time ; and (iii) the water table and the river discharge increase are concomitant. Dynamics (i) and (ii) are observed during the ENSO events, when precipitation occurs over a long time period ; dynamic (iii) is observed during the neutral years, when high intensity precipitations occur over short periods. The analysis of these dynamics and runoff coefficients shows that when the mean annual precipitation is less than 70 mm, the relative equilibrium between runoff and recharge processes is broken, which may generate a high hydrological deficit; this threshold could thus be used as a warning for drought. Finally, the spatial variability of runoff coefficients shows a larger contribution of the subsurface compartment in catchment with a larger proportion of granites, suggesting a mountain front recharge from the alterites in the granitic watershed.
Año: 2012
Palabras claves: hydro-climatic variability, water resource, surface, subsurface interactions, snowmelt, Río Elqui, North-Central Chile.
Referencia APA: Jourde, H., Blanc, M., Rochette, R., Ruelland, D., Hicks, E., & Oyarzun, R. (2012). Caractérisation des interactions entre flux souterrains et superficiels dans un bassin andin en fonction de la variabilité spatio-temporelle du climat. La Houille Blanche, (2), 18-25
Activity patterns and predatory behavior of an intertidal nemertean from rocky shores: Prosorhochmus nelsoni (Hoplonemertea) from the Southeast Pacific.
Caplins, S., Penna-Diaz, M., Godoy, E., Valdivia, N., Turbeville, J., & Thiel, M.
Understanding the impact of environmental stressors on predator activity is a prerequisite to understanding the underlying mechanisms shaping community structure. The nemertean Prosorhochmus nelsoni is a common predator in the mid-intertidal zone on rocky shores along the Chilean coast, where it can reach very high abundances (up to 260 ind m−2) in algal turfs, algal crusts, barnacle crusts, and mixed substrata. Tidal and diurnal scans revealed that the activity of P. nelsoni is primarily restricted to night and early-morning low tides and is relatively low when air temperatures are high. On average, larger worms crawled faster than smaller worms, with their maximum velocity being influenced by substratum type. Their estimated rate of predation is 0.092 prey items nemertean−1 day−1, just below the laboratory rate of ~0.2 amphipods nemertean−1 day−1 previously estimated for this species. P. nelsoni consumes a diverse spectrum of prey items (i.e., amphipods, isopods, decapods, barnacles, and dipterans) and is possibly exerting a significant influence on its prey populations. We suggest that the opportunistic predatory behavior of this intertidal predator is caused by the trade-off between immediate persistence (e.g., avoidance of desiccation) and long-term survival through successful foraging.
Año: 2012
Palabras claves:
Referencia APA: Caplins, S., Penna-Diaz, M., Godoy, E., Valdivia, N., Turbeville, J., & Thiel, M. (2012). Activity patterns and predatory behavior of an intertidal nemertean from rocky shores: Prosorhochmus nelsoni (Hoplonemertea) from the Southeast Pacific. Marine Biology, 159(6), 1363-1374.
Application of water quality indices and analysis of the surface water quality monitoring network in semiarid North-Central Chile
Espejo, L., Kretschmer, N., Oyarzún, J., Meza, F., Núñez, J., Maturana, H., Soto, G., Oyarzo, P., Garrido, M., Suckel, F., Amezaga, J., Oyarzún, R.
Surface water quality has increasing importance worldwide and is particularly relevant in the semiarid North-Central Chile, where agriculture and mining activities are imposing heavy pressure on limited water resources. The current study presents the application of a water quality index in four watersheds of the 29°–33°S realm for the period 1999–2008, based on the Canadian Council of Ministers for the Environment approach and the Chilean regulation for irrigation water quality. In addition, two modifications to the index are tested and a comprehensive characterization of the existing monitoring network is performed through cluster analysis. The basins studied show fairly good water quality in the overall, specially the Limarí basin. On the other hand, the lower index values were obtained for the headwaters of Elqui, associated with the El Indio mining district. The first modification of the indicator (i.e., to consider parameters differentially according to their effect on human health or the environment) did not produce major differences with respect to the original index, given the generally good water quality. The second modification (i.e., to consider as threshold values the more restrictive figures derived from a set of regulations) yielded important differences in the indicator values. Finally, an adequate characterization of the monitoring network was obtained. The results presented spatial coherence and the information can be used as a basis for the optimization of the monitoring network if required.
Año: 2012
Palabras claves: CCME-WQI, Secondary water quality regulations, Physicochemical parameters, Heavy metals, Cluster analysis.
Referencia APA: Espejo, L., Kretschmer, N., Oyarzún, J., Meza, F., Núñez, J., & Maturana, H. et al. (2012). Application of water quality indices and analysis of the surface water quality monitoring network in semiarid North-Central Chile. Environmental Monitoring And Assessment, 184(9), 5571-5588.
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.