Recent variations of supraglacial lakes on the Baltoro Glacier in the central Karakoram Himalaya and its possible teleconnections with the pacific decadal oscillation

This study discusses the formation and variations of supraglacial lakes on the Baltoro glacier system in the central Karakoram Himalaya during the last four decades. We mapped supraglacial lakes on the Baltoro Glacier from 1978 to 2014 using Landsat MSS, TM, ETM + and LCDM images. Most of the glacial lakes were formed or expanded during the late 1970s–2008. After 2008, the total number and the area of glacial lakes were found to be lesser compared to previous years. We tried to find any teleconnections exists between the glacial lake changes in this region and the pacific decadal oscillation (PDO), which entered its prolonged warm regime in the late 1970s and again to its cold regime in 2008, based on observational investigation. The decrease in the number and area of the supraglacial lakes after 2008 is hypothesised to be linked with the recent cold phase of PDO.     

Integrating variations in the soil chloride profile and evaporativity for in-situ estimation of evaporation in arid zones: an application in south-eastern Morocco

In arid regions, knowledge of the evaporation rate from the water table is essential for appropriate management of scarce resources and to prevent land degradation. Soil chloride profiles in the unsaturated zone of a bare soil in an arid area of south-eastern Morocco were used to assess the evaporation flux, using chloride inventories in conjunction with evaporative demand. Moisture fluxes were calculated from measured chloride concentrations on the basis of a steady-state flow model. The chloride profiles displayed large variations in concentrations and had (1) low chloride concentrations near the soil surface, (2) maximum chloride concentrations at depths of 11–14 cm beneath the soil surface, respectively in July and February, and (3) gradually decreasing chloride concentrations while depth increased below these peaks. Evaporative demands were found to be inversely proportional to the depth of evaporation fronts and proportional to evaporation fluxes. In addition, the evaporation along the profiles seems to be controlled by the soil composition and texture. The investigation of chloride profiles in February and July enabled the determination of a value for annual evaporation (～30 mm), which is in good agreement with the value estimated by the Allison-Barnes type model (～32 mm).     

Impact of trace metals on denitrification in estuarine sediments of the Douro River estuary,Portugal

Denitrification influences the nitrogen budget in estuaries by removing fixed nitrogen from the inorganic pool; rates are dependent on both geological and geographic conditions as well as increasing anthropogenic impacts. In this study the effects of copper (Cu), chromium (Cr), zinc (Zn), cadmium (Cd) and lead (Pb), on the denitrification pathway were evaluated in subtidal and intertidal sediments of the Douro River estuary. Dinitrogen, N₂O and NO₂⁻ production rates were measured in triplicate slurries of field samples under different treatments of metal concentrations. Results demonstrated that similar metal amendments led to different site responses for denitrification, suggesting that variations in sediment properties (metal concentrations, grain size, organic matter content, etc.) and/or differences in denitrifying community tolerance modulate the level of metal toxicity. Denitrifying communities in subtidal muddy sediments were not affected by increasing concentrations of metals. In contrast, intertidal sandy sites revealed high sensitivity to almost all trace metals tested; almost complete inhibition by Cr (95%) and Cu (85%) was observed for 98 and 79 μg per gram of wet sediment respectively, and by Zn (92%) at the highest concentration added (490 μg per gram of wet sediment). Moreover, the addition of trace metals stimulated N₂O and NO₂⁻ accumulation in intertidal sandy (Zn, Cu, Cr and Cd) and muddy sediments (Cu and Zn), demonstrating a pronounced inhibitory effect on specific steps within the denitrification enzymatic system. In summary, the results obtained suggest that, according to the type of estuarine sediment, trace metals cannot only reduce total N removal from an estuary via denitrification but also can enhance the release of N₂O, a powerful greenhouse gas.     

137Cs, 60Co and 125I bioaccumulation by seaweeds from the Angra dos Reis nuclear power plant region

As part of a broad research program on the behavior of critical radionuclides to be discharged into the sea by the first Brazilian nuclear powerplant, the uptake accumulation and loss of ¹³⁷Cs, ⁶⁰Co and ¹²⁵I by locally abundant seaweed species was studiedUptake in static 12 liter aquarium experiments reached apparent steady-state in 2–7 days (⁶⁰Co and ¹²⁵I) or 2–3 weeks (¹³⁷Cs). Elimination followed a reverse pattern, being comparatively fast for ¹³⁷Cs and slow for ⁶⁰Co and ¹²⁵I. Dry weight bioaccumulation factors (BFs) were variable, falling in the 10¹ range for ¹³⁷Cs, 10³ for ¹²⁵I and 10³–10⁴ for ⁶⁰Co. Various short-term experiments performed over a 16 month period, showed marked temporal variations of ⁶⁰Co BFs for all species.The results demonstrated that the studied species may play an important role in the transfer of the critical radionuclides through local food webs and can be employed as useful monitors for routine or accidental radionuclide releases.     

Alteration de la fonction de reproduction chez Idotea balthica basteri (Crustacea,Isopoda) soumis a l'effet chronique d'un détergent non ionique

Reproduction is greatly affected when the crustacean isopod Idotea balthica basteri is exposed to detergents, maturation being considerably delayed. Adults suffer a significant decrease in fecundity, either through females failing to produce eggs or miscarrying, and so producing fewer juveniles. This decrease of fecundity is accompanied by hormonal changes. Many juveniles from animals exposed to detergents are malformed.     

Cenozoic tectonics on the Galicia margin,northwest Spain

Neogene tectonic activity (Betic Orogeny) along the southern plate boundary of Iberia, as it converged with Africa and the Alboran Plate was inserted between them, propagated along Iberia's west side as far north as Galicia, northwest Spain. As the activity propagated northward, it reactivated structures formed during the Paleozoic (Hercynian), the Early Cretaceous opening of the northern North Atlantic and the Bay of Biscay, and the Paleogene Pyrenean Orogeny when Iberia collided with Eurasia. Recent earthquakes indicate that this tectonism is still active today as far north as northwest Spain.     

Chloride transfer in cement‐based materials. Part 1. Theoretical basis and modelling

In this first part of the work, we develop macroscopic models for migration and diffusion–migration of ionic species in saturated porous media, based on periodic homogenization. The prior application is chloride transport in cementitious materials. The dimensional analysis of Nernst–Planck equation lets appear to dimensionless numbers characterizing the ionic transfer in the porous medium. Using experimental data obtained from electrodiffusion tests on cement‐based materials (Part II), these dimensionless numbers are linked to the perturbation parameter ?. For a strong imposed electrical field, the asymptotic expansion of Nernst–Planck equation leads to a macroscopic model where the migration is predominant. For a weak imposed electrical field or in natural diffusion, we obtain a macroscopic model coupling diffusion and migration at the same order. In both models, the expression of the homogenized diffusion tensor is identical and only involves the geometric properties of the material microstructure. Copyright © 2012 John Wiley & Sons, Ltd.     

Depuration dynamics of oysters (Crassostrea gigas) artificially contaminated by Salmonella enterica serovar Typhimurium

The State of Santa Catarina produces the greatest quantity of edible mollusks in Brazil. To guarantee sanitary qualify, mollusk cultures should be monitored for contamination by pathogenic microorganisms. A self-purification or "depuration" system that eliminates Salmonella enterica serovar Typhimurium contamination from oysters has been developed and evaluated. The depuration process occurred within a closed system, in which 1000 L of water was recirculated for 24 h. The water was sterilized with ultraviolet (UV) light, chlorine, or both together. Oysters (Crassostrea gigas) artificially contaminated with S. typhimurium were harvested every 6 h. Samples of oyster tissue were excised and both the presence and numbers of bacteria were determined. Combined UV light and chlorine treatments resulted in total elimination of bacteria within 12 h. Polymerase chain reaction detected bacteria in water exposed to the three treatments. This pioneering study is the first of its kind in Brazil and represents a major contribution to commercial mollusk culture in this country.