Paracas dust storms: Sources, trajectories and associated meteorological conditions

Autores:

Briceño-Zuluaga, F., Castagna, A., Rutllant, J.A., Flores-Aqueveque, V., Caquineau, S., Sifeddine, A., Velazco, F., Gutierrez, D., Cardich, J.

Resumen:

Dust storms that develop along the Pisco-Ica desert in Southern Peru, locally known as “Paracas” winds have ecological, health and economic repercussions. Here we identify dust sources through MODIS (Moderate Resolution Imaging Spectroradiometer) imagery and analyze HYSPLIT (Hybrid Single Particles Lagrangian Integrated Trajectory) model trajectories and dispersion patterns, along with concomitant synoptic-scale meteorological conditions from National Centers for Environmental Prediction/National Center for Atmospheric Research reanalysis (NCEP/NCAR). Additionally, surface pressure data from the hourly METeorological Aerodrome Report (METAR) at Arica (18.5°S, 70.3°W) and Pisco (13.7°S, 76.2°W) were used to calculate Alongshore (sea-level) Pressure Gradient (APG) anomalies during Paracas dust storms, their duration and associated wind-speeds and wind directions. This study provides a review on the occurrence and strength of the Paracas dust storms as reported in the Pisco airfield for five-year period and their correspondence with MODIS true-color imagery in terms of dust-emission source areas. Our results show that most of the particle fluxes moving into the Ica-Pisco desert area during Paracas wind events originate over the coastal zone, where strong winds forced by steep APGs develop as the axis of a deep mid-troposphere trough sets in along north-central Chile. Direct relationships between Paracas wind intensity, number of active dust-emission sources and APGs are also documented, although the scarcity of simultaneous METAR/MODIS data for clearly observed MODIS dust plumes prevents any significant statistical inference. Synoptic-scale meteorological composites from NCEP/NCAR reanalysis data show that Paracas wind events (steep APGs) are mostly associated with the strengthening of anticyclonic conditions in northern Chile, that can be attributed to cold air advection associated with the incoming trough. Compared to the MODIS images, HYSPLIT outputs were able to spatially reproduce trajectories and dust dispersion plumes during the Paracas wind storms. HYSPLIT trajectories revealed that part of the wind-eroded lithological material can be transported downwind several kilometers along the Peruvian coast and also deposited over the nearby coastal ocean, giving support to the presence of an aeolian signal in continental shelf sediments, of great importance for paleoenvironmental studies.

Año: 2017

Palabras claves: Aeolian transport, HYSPLIT trajectories, Dust storms, Southern, Peru, Synoptic-scale meteorological patterns

Reproductive patterns in demersal crustaceans from the upper boundary of the OMZ off north-central Chile

Autores:

Gallardo, M., González López, A., Ramos, M., Mujica, A., Muñoz, P., Sellanes, J. and Yannicelli, B.

Resumen:

Pleuroncodes monodon (Crustacea: Munididae) supports one of the main trawling fisheries over the continental shelf off Chile between 25°S and 37°S within the upper boundary of the oxygen minimum zone (OMZ). Although the reproductive cycle of P. monodon has been described, the relationship between this key biological process and the variability of the OMZ has not been comprehensibly addressed neither for P. monodon nor for other OMZ resident species. In this study a set of 14 quasi-monthly oceanographic cruises carried out between June 2010 and November 2011 were conducted over the continental shelf off Coquimbo (30°S) to investigate the temporal variability of: i) dissolved oxygen concentration, temperature and chlorophyll-a at relevant depths ii) the presence and proportion of occurrence of P. monodon ovigerous females and juveniles from benthic trawls; iii) the presence of different stage larvae in the plankton, and iv) similar biological data for other species from the OMZ and shallower depths crustaceans. During summer months oxygen levels and bottom temperature were lower than in winter, while chlorophyll-a concentration was maximum in summer coinciding with an active (but not maximum) upwelling season. P. monodon maximum egg carrying occurred in winter during periods of increased oxygenation. Egg carrying females were never found at depths where oxygen concentration was below 0.5 ml L−1, while over 50% of the autumn and spring cohorts of juveniles occurred at oxygen concentrations below that level. The depth range occupied by ovigerous females was more restricted than the rest of the population and their depth of occurrence followed the variability of the upper OMZ. The larval release period of OMZ resident species extends over late winter and spring, and its main peak precedes that of coastal species (spring) and the spring-summer chlorophyll-a maximum. We propose that for OMZ resident species, brood carrying during warmer and more oxygenated conditions in the adult benthic environment, might favor embryonic development, so OMZ seasonal variability could be acting as a selective pressure to synchronize reproductive periods.

Año: 2017

Palabras claves: Pleuroncodes monodonOxygen Minimum ZoneReproductive cycleLarval releaseHumboldt currents systems

Recent Deceleration of the Ice Elevation Change of Ecology Glacier (King George Island, Antarctica)

Autores:

Pętlicki, M., Sziło, J., MacDonell, S., Vivero, S. and Bialik, R.

Resumen:

Glacier change studies in the Antarctic Peninsula region, despite their importance for global sea level rise, are commonly restricted to the investigation of frontal position changes. Here we present a long term (37 years; 1979–2016) study of ice elevation changes of the Ecology Glacier, King George Island (62∘11′S, 58∘29′W). The glacier covers an area of 5.21 km2 and is located close to the H. Arctowski Polish Antarctic Station, and therefore has been an object of various multidisciplinary studies with subject ranging from glaciology, meteorology to glacial microbiology. Hence, it is of great interest to assess its current state and put it in a broader context of recent glacial change. In order to achieve that goal, we conducted an analysis of archival cartographic material and combined it with field measurements of proglacial lagoon hydrography and state-of-art geodetic surveying of the glacier surface with terrestrial laser scanning and satellite imagery. Overall mass loss was largest in the beginning of 2000s, and the rate of elevation change substantially decreased between 2012–2016, with little ice front retreat and no significant surface lowering. Ice elevation change rate for the common ablation area over all analyzed periods (1979–2001–2012–2016) has decreased from −1.7 ± 0.4 m/year in 1979–2001 and −1.5 ± 0.5 m/year in 2001–2012 to −0.5 ± 0.6 m/year in 2012–2016. This reduction of ice mass loss is likely related to decreasing summer temperatures in this region of the Antarctic Peninsula.

Año: 2017

Palabras claves: glaciology; ice elevation change; glacial retreat; DEM; Terrestrial Laser Scanning; Antarctica; South Shetland Islands

The Andes Cordillera. Part I: snow distribution, properties,and trends (1979–2014)

Autores:

Mernild, S., Liston, G., Hiemstra, C., Malmros, J., Yde, J. and McPhee, J.

Resumen:

Snow cover presence, duration, properties, and water amount play a major role in Earth’s climate systemthrough its impact on the surface energy budget. Snow cover conditions and trends (1979–2014) were simulated for SouthAmerica – for the entire Andes Cordillera. Recent data sets and SnowModel developments allow relatively high-resolutionsof 3-h time step and 4-km horizontal grid increment for this domain. US Geological Survey’s Global Multi-resolution TerrainElevation Data 2010 topography, Global Land Cover (GlobCover), Randolph Glacier Inventory (v. 4.0) glacier, and NASAmodern-era retrospective analysis for research and a pplications data sets were used to simulate rst-order atmospheric forcing(e.g. near-surface air temperature and precipitation, including the fraction of precipitation falling as snow) and terrestrial snowcharacteristics (e.g. snow cover days, snow water equivalent depth, and snow density). Simulated snow conditions were veriedagainst moderate-resolution imaging spectroradiometer-derived snow cover extent and 3064 individual direct observations ofsnow depths. Regional variability in mean annual air temperature occurred: positive trends in general were seen in the highAndes Cordillera, and negative trends at relatively lower elevations both east and west of the Cordillera. Snow precipitationshowed more heterogeneous patterns than air temperature due to the inuence from atmospheric conditions, topography, andorography. Overall, for the Cordillera, much of the area north of 23∘S had a decrease in the number of snow cover days, whilethe southern half experienced the opposite. The snow cover extent changed ∼−15% during the simulation period, mostlybetween the elevations of ∼3000 and 5000 m above sea level (a.s.l.). However, below 1000 m a.s.l. (in Patagonia) the snowcover extent increased. The snow properties varied over short distances both along and across the Andes Cordillera.

Año: 2016

Palabras claves: Andes Cordillera; modelling; NASA MERRA; MODIS; SnowModel; snow; snow classication; South America

Diversification dynamics, species sorting, and changes in the functional diversity of marine benthic gastropods during the Pliocene-Quaternary at temperate western South America

Autores:

Rivadeneira MM, Nielsen SN

Resumen:

Functional diversity based on species traits is a powerful tool to investigate how changes in species richness and composition affect ecosystem functioning. However, studies aimed at understanding changes in functional diversity over large temporal and spatial scales are still scant. Here we evaluate the combined effect of diversification and species sorting on functional diversity of fossil marine gastropods during the Pliocene-Quaternary transition in the Pacific coast of South America. We analyzed a total of 172 species in 29 Pliocene and 97 Quaternary sites. Each species was characterized according to six functional traits: body size, feeding type, mobility, attachment, life-habit, and larval mode. Functional diversity was estimated according to four indexes (functional richness, evenness, divergence and dispersion) based on functional traits measured. Extrapolated species richness showed a slight yet not significant decrease from the Pliocene to the Quaternary despite the fact that a large faunal turnover took place; furthermore, a large extinction of Pliocene species (61–76%) was followed by a high pulse of appearances (49–56%) during the Quaternary. Three out of four indices of functional diversity (evenness, divergence and dispersion) increased significantly towards the Quaternary which is more than expected under a random turnover of species. The increase in functional diversity is associated with a loss of large-sized carnivore forms, which tended to be replaced by small-sized grazers. Hence, this trait-selective species turnover, even in the absence of significant changes in species richness, likely had a large effect and has shaped the functional diversity of present-day assemblages.

Año: 2017

Palabras claves: Species diversity, Species extinction, Pliocene epoch, Physiological parameters, Gastropods, Biodiversity, Malacology, Marine fossils.

The importance of scale-dependent ravine characteristics on breeding-site selection by the Burrowing Parrot, Cyanoliseus patagonus

Autores:

Ramirez-Herranz, M., Rios, R., Vargas-Rodriguez, R., Novoa-Jerez, J. and Squeo, F.

Resumen:

In birds, the environmental variables and intrinsic characteristics of the nest have important fitness consequences through its influence on the selection of nesting sites. However, the extent to which these variables interact with variables that operate at the landscape scale, and whether there is a hierarchy among the different scales that influences nest-site selection, is unknown. This interaction could be crucial in burrowing birds, which depend heavily on the availability of suitable nesting locations. One representative of this group is the burrowing parrot, Cyanoliseus patagonus that breeds on specific ravines and forms large breeding colonies. At a particular site, breeding aggregations require the concentration of adequate environmental elements for cavity nesting, which are provided by within ravine characteristics. Therefore, intrinsic ravine characteristics should be more important in determining nest site selection compared to landscape level characteristics. Here, we assess this hypothesis by comparing the importance of ravine characteristics operating at different scales on nest-site selection and their interrelation with reproductive success. We quantified 12 characteristics of 105 ravines in their reproductive habitat. For each ravine we quantified morphological variables, distance to resources and disturbance as well as nest number and egg production in order to compare selected and non-selected ravines and determine the interrelationship among variables in explaining ravine differences. In addition, the number of nests and egg production for each reproductive ravine was related to ravine characteristics to assess their relation to reproductive success. We found significant differences between non-reproductive and reproductive ravines in both intrinsic and extrinsic characteristics. The multidimensional environmental gradient of variation between ravines, however, shows that differences are mainly related to intrinsic morphological characteristics followed by extrinsic variables associated to human disturbance. Likewise, within reproductive ravines, intrinsic characteristics are more strongly related to the number of nests. The probability of producing eggs, however, was related only to distance to roads and human settlements. Patterns suggest that C. patagonus mainly selects nesting sites based on intrinsic morphological characteristics of ravines. Scale differences in the importance of ravine characteristics could be a consequence of the particular orography of the breeding habitat. The arrangement of resources is associated to the location of the gullies rather than to individual ravines, determining the spatial availability and disposition of resources and disturbances. Thus, nest selection is influenced by intrinsic characteristics that maximize the fitness of individuals. Scaling in nest-selection is discussed under an optimality approach that partitions patch selection based on foraging theory.

Año: 2017

Palabras claves: Nesting site, Burrowing bird, Intrinsic morphological characteristic, Foraging, Landscape variables.

Genetic variation of loci potentially under selection confounds species–genetic diversity correlations in a fragmented habitat

Autores:

Bertin, A., Gouin, N., Baumel, A., Gianoli, E., Serratosa, J., Osorio, R. and Manel, S.

Resumen:

Positive species–genetic diversity correlations (SGDCs) are often thought to result from the parallel influence of neutral processes on genetic and species diversity. Yet, con-founding effects of non-neutral mechanisms have not been explored. Here, we investigate the impact of non-neutral genetic diversity on SGDCs in high Andean wetlands.We compare correlations between plant species diversity and genetic diversity (GD)calculated with and without loci potentially under selection (outlier loci). The study system includes 2188 specimens from five species (three common aquatic macroinvertebrate and two dominant plant species) that were genotyped for 396 amplified fragment length polymorphism loci. We also appraise the importance of neutral processes onSGDCs by investigating the influence of habitat fragmentation features. Significant positive SGDCs were detected for all five species (mean SGDC = 0.52  0.05). While only a few outlier loci were detected in each species, they resulted in significant decreases in GD and in SGDCs. This supports the hypothesis that neutral processes drive species–genetic diversity relationships in high Andean wetlands. Unexpectedly, the effects on genetic diversity GD of the habitat fragmentation characteristics in this study increased with the presence of outlier loci in two species. Overall, our results reveal pitfalls in using habitat features to infer processes driving SGDCs and show that a few loci potentially under selection are enough to cause a significant downward bias in SGDC. Investigating confounding effects of outlier loci thus represents a useful approach to evidence the contribution of neutral processes on species–genetic diversity relationships.

Año: 2017

Palabras claves: Community genetics, connectivity, habitat, high Andean wetlands, outlier loci,species–genetic diversity correlations.

The Revival of Quinoa: A Crop for Health

Autores:

Lutz, M., Bascuñan-Godoy, L.

Resumen:

Quinoa (Chenopodium quinoa Willd.) is a basic food in pre‐hispanic Andean communities, used not only as a food but also for medicinal purposes. The interest in quinoa has increased because of its plasticity to adapt to environmental conditions: it tolerates frost, salinity and drought; it grows on marginal and arid soils and high altitudes. The nutritional quality of quinoa is well recognized: protein content ranges 13–17 g/100 g, with an amino acid score above 1.0 and it is gluten free. The grain contains starch and free sugars, with a glycemic index ranging 35–53, depending on the cooking time. It also contains bioactive phytochemicals such as dietary fiber, carotenoids, phytosterols, squalene, fagopyritols, ecdysteroids and polyphenols. The composition of quinoa varies among ecotypes and is affected by environmental factors: some amino acids and phytochemicals augment under stress episodes. The rationale for the revival of quinoa and its reintroduction into the diet is related with the epidemiological situation, which includes diseases that exhibit risk factors that may be reduced with a balanced nutritious diet, in which quinoa plays a major role, being considered as a “superfood.” Moreover, it is one of the crops selected by Food and Agriculture Organization (FAO) to offer food security.

Año: 2017

Palabras claves: Quinoa, Chenopodium quinoa Willd., ancient crop, nutritional quality, chemical composition, bioactives, health, crop plasticity.

Towards local governance of marine resources and ecosystems on Easter Island

Autores:

Aburto, J. A., Gaymer, C. F., and Cundill, G.

Resumen:

1.- Social-ecological system sustainability depends in part upon the fit between ecosystems and institutions.

2.- In 2014, the local community on Easter Island started a bottom-up process to improve marine resources conservation and management.

3.- Local stakeholders formed a working group that has regular meetings and goals, such as creating a sea council and some basic action plans, thus initiating a local governance transformation process.

4.- A participatory process was conducted together with a local organization that led the marine conservation issues on the island to define the factors that could favour and/or undermine the formation of the sea council. Also, the stakeholders that must be present in such a sea council were identified.

5.- Twelve factors that could facilitate or hinder the implementation of a sea council were identified. The lack of representativeness of public institutions is a major challenge.

6.- Public institutions are designed to ensure compliance with central government strategies, but the decisions do not represent the worldview of islanders.

7.- The results showed the potential value of conducting a participatory process to identify the key issues that could hinder or favour a desired governance transformation process. The participatory process also highlighted governance mismatches that are important to consider in attempts to pursue more effective fishery governance on Easter Island, and other Island communities.

8.- Centralized governance systems do not respond rapidly to locally observed social and ecological dynamics. By contrast, a local decision-making system based on traditional laws and local governance can more rapidly respond to observed changes.

9.- The participatory process presented here holds the potential to support local people in their planning and coordination for marine conservation and management in order to optimize bottom-up change processes involving multiple stakeholders with different interests, values and levels of power.

Año: 2017

Palabras claves: Local governance; community-based management; participation; bottom-up process; Easter Island; stakeholder analysis; social-ecological fit.

Influence of seasonal freshwater streamflow regimes on phytoplankton blooms in a Patagonian fjord

Autores:

Iriarte, J.L., Leon-Muñoz, J., Marcé, R., Clément, A., Lara, C.

Resumen:

Large-scale regional phenomena and global climate trends may alter the freshwater discharge of large Patagonian rivers and could modify local circulation patterns in ways that influence phytoplankton dynamics. Modifications detected in the streamflow regime of the Puelo River (41.5° S, Patagonia, Chile) in recent decades may affect the regularity of seasonal phytoplankton blooms in Reloncaví Fjord. We examined the occurrence/frequency of spring–summer and autumn phytoplankton blooms in Reloncaví Fjord with respect to seasonal and inter-annual changes in freshwater streamflows from 2003 to 2011. Surface chlorophyll-a derived from satellite-ocean colour and phytoplankton abundances revealed that significant recurrences of autumn phytoplankton blooms (> 2 mg Chl-a m−3, > 500 cell mL−1) were associated with historical low mean freshwater streamflows, mainly in autumn (< 350 m3 s−1). On the other hand, the occurrence of spring–summer blooms was related to high streamflows (> 470 m3 s−1) that increased mixing in the upper photic layer enough to enhance phytoplankton growth. Our findings imply that the intensity of autumn blooms in Reloncaví Fjord could be modulated by streamflow strength.

Año: 2017

Palabras claves: Chlorophyll-a, hydrological regimes, Patagonian fjords, phytoplankton blooms, satellite-ocean colour.