In the southwestern United States, precipitation in the high mountains is a primary source of groundwater recharge. Precipitation patterns, soil properties and vegetation largely control the rate and timing of groundwater recharge. The interactions between climate, soil and mountain vegetation thus have important implications for the groundwater supply. This study took place in the Sacramento Mountains, which is the recharge area for multiple regional aquifers in southern New Mexico. The stable isotopes of oxygen and hydrogen were used to determine whether infiltration of precipitation is homogeneously distributed in the soil or whether it is partitioned among soil-water ‘compartments’, from which trees extract water for transpiration as a function of the season. The results indicate that “immobile” or “slow” soil water, which is derived primarily from snowmelt, infiltrates soils in a relatively uniform fashion, filling small pores in the shallow soils. “Mobile” or “fast” soil water, which is mostly associated with summer thunderstorms, infiltrates very quickly through macropores and along preferential flow paths, evading evaporative loss. It was found that throughout the entire year, trees principally use immobile water derived from snowmelt mixed to differing degrees with seasonally available mobile-water sources. The replenishment of these different water pools in soils appears to depend on initial soil-water content, the manner in which the water was introduced to the soil (snowmelt versus intense thunderstorms), and the seasonal variability of the precipitation and evapotranspiration. These results have important implications for the effect of climate change on recharge mechanisms in the Sacramento Mountains.

Uruguay has a dense hydrographic network, nevertheless the knowledge of the aquatic macroinvertebrate community is still lacking. In recent decades afforestation with exotic species has increased which has produced changes in riparian vegetation of some rivers. The aim of this research was to determine the composition and trophic structure of macroinvertebrate community and its relationship to some physicochemical parameters in eight streams where the native forest is still well preserved and provide the basis for future studies. Samples were collected from December 2006 to December 2007. Temperature, dissolved oxygen, pH and conductivity were measured in situ. Taxonomic composition and abundance were determined, a principal component analysis and a canonical correspondence analysis were carried out with the physico-chemical and biological parameters. The alpha diversity was calculated using the Shannon-Weaver (H'), dominance of Simpson (D) and Pielou evenness indexes (J'). Beta diversity was determined employing similarity index of Bray-Curtis. A total of 1 291 specimens belonging 92 taxa were recorded. The most abundant taxa were Ephemeroptera (36%), Amphipoda (17%) and Coleoptera (12%). The streams show high diversity and low dominance. Conductivity, pH, and temperature were the main factors in determining the macroinvertebrate distribution and composition.

En este trabajo se ha estudiado la influencia del portainjerto sobre la composicion isotopica del mosto de vid (Vitis vinifera, L.). Las plantas de Cabernet Sauvignon injertadas sobre 101-14, 420A y 41B fueron cultivadas al aire libre y sometidas a tres regimenes hidricos. El portainjerto modifico de forma estadisticamente significativa el contenido de oxigeno-18 en el agua del mosto. Se observo que el enriquecimiento en oxigeno-18 estaba correlacionado positivamente con la diferencia de temperatura entre la canopy y el aire. Probablemente, la reduccion del factor de fraccionamiento de equilibrio no fue suficiente para compensar el enriquecimiento a traves del aumento del factor de fraccionamiento cinetico, debido al aumento del VPD en condiciones de baja disponibilidad hidrica. El 41B indujo el mayor enriquecimiento a pesar de evidenciar la mas elevada transpiracion foliar. Las diferencias observadas en la composicion isotopica del mosto podrian ser debidas a la influencia del portainjerto sobre la conductancia estomatica foliar y sobre la transpiracion de las bayas. Los resultados obtenidos pueden contribuir a aclarar ciertos aspectos en los estudios sobre la caracterizacion y autenticacion de vinos y otros productos agroalimentarios.

El analisis de los isotopos naturales del agua son una potente herramienta para caracterizar y autenticar el origen de los productos agroaliemtarios en general. En este trabajo se ha estudiado la influencia del regimen hidrico del suelo sobre la composicion isotopica del mosto de vid (Vitis vinifera L. cv. Cabernet Sauvignon) en condiciones de campo.

The present study examined the effect of experimentally elevating dietary Ca2+ and water hardness on survival and growth of silver catfish, Rhamdia quelen, exposed to different waterborne NH3 and O2 levels. In the dietary Ca2+ experiment of determination of NH3 lethal concentration in 96 h (LC50-96h) juveniles (4.06±0.27g and 7.82±1.2cm) were exposed to five different NH3 levels (in mg.L-1): 0.107±0.007 (control), 0.36±0.021, 0.773±0.074, 1.170±0.071 and 1.63±0.315 and four dietary Ca2+ levels (in % Ca2+): 0.45, 0.95, 1.45, and 2.45. In the waterborne Ca2+ experiment of LC50-96h juveniles (1.85±0.6g and 6.0±0.54cm) were maintained at five different NH3 levels (mg.L-1): 0.097±0.017 (control), 0.356±0.037, 0.779±0.141, 1.459±0.185 and 1.770±0.070 and four water hardness levels (in mg CaCO3.L-1): 34.5±4.4, 62.0±5.7, 116.0±9.3, and 174.0±22.42. In the dietary Ca2+ experiment of determination of O2 lethal concentration in 96 h (LC50-96h) juveniles (4.75 + 0.65 g e 7.56 + 0.61 cm) were exposed to five different O2 levels (in mg.L-1): (0.41±0.13, 0.71±0.15, 0.97±0.13, 1.44±0.35 e 6.41±0.60 mg/L) and four dietary Ca2+ levels (in % Ca2+): 0.45, 0.95, 1.45, and 2.45. In the waterborne Ca2+ experiment of LC50-96h juveniles (3.66 ± 0.75 g e 7.32± 0.5 cm) were maintained at five different O2 levels (mg.L-1): (0.27±0.10, 0.74±0.26, 1.33±0.14, 1.74±0.32 e 6.55±0.02 mg.L-1) and four water hardness levels (in mg CaCO3.L-1): (28, 116, 116 e 180). In the growth experiment juveniles (2.27±0.14g and 6.9±0.13cm) were exposed to two NH3 levels (mg.L-1), 0.021±0.001 and 0.623±0.039, and four water hardness levels (mg CaCO3.L-1): 32.1±4.6, 63.1±5.9, 119.9±10.0, and 177.3±8.1 for 40 days. In the growth experiment juveniles (3.66±0.75g and 7.32±0.5cm) were exposed to two O2 levels (1.47±0.04 and 6.46±0.06 mg.L-1), and four water hardness levels (mg CaCO3.L-1): 30±2.0, 61±2.5, 121±3.0 e 180±3.0 for 15 days. The NH3 LC50-96h was 0.73 mg.L-1 (0.63 - 0.84) in the dietary Ca2+ experiment, and LC50-96h was significantly higher in juveniles fed 0.45 and 0.95% dietary Ca2+. Water hardness did not change significantly NH3 LC50-96h, which was1.20 mg.L-1 (1.10 - 1.24). Weight gain, biomass and specific growth rate at end of the growth experiment were significantly higher in juveniles exposed to 0.021 mg.L-1 NH3 than those exposed to 0.623 mg.L- NH3. The increase of water hardness impaired all measured parameters in juveniles exposed to the lowest NH3 level, but increased them in those exposed to the highest NH3 level. The O2 LC50-96h was 0.89 mg/L (CI 0.64 1.34 mg/L) in the dietary Ca2+ experiment, and LC50-96h was significantly higher in juveniles fed 2.45 e 0.45% dietary Ca2+. Weight gain, biomass, length and specific growth rate at end of the growth experiment were significantly higher in juveniles exposed to 6.46±0.06 than those exposed to 1.47±0.04 mg.L-1O2 . The increase of water hardness increased all measured parameters in juveniles exposed to the lowest O2 level, but them impaired in those exposed to the highest O2 level. This study indicates that low dietary Ca2+ enhanced survival of silver catfish exposed to high NH3 and low O2 levels, and that the increase of water hardness is recommended only when this species is raised in waters with high growth NH3 and low O2 levels. | Este trabalho teve como objetivos verificar os efeitos da adição de Ca2+ na ração e na água na sobrevivência e crescimento de juvenis de jundiá (Rhamdia quelen) submetidos a diferentes níveis de amônia e oxigênio dissolvido. No experimento para verificar a eficácia da adição de Ca2+ na ração sobre a concentração letal 96h (CL50-96h) da amônia (NH3) os juvenis (4.06±0.27g e 7.82±1.2cm) foram expostos a cinco níveis de NH3 (em mg/L): 0,107±0,007 (controle); 0,360±0,021; 0,773±0,074; 1,170±0,071 e 1,630±0,315 e quatro níveis de Ca2+ na dieta (em % Ca2+): 0,45; 0,95; 1,45 e 2,45. Para verificar a eficácia do Ca2+ na água sobre a CL50-96h da NH3 , os juvenis (1,85±0,6g e 6,0±0,54cm) foram mantidos em cinco níveis de NH3 (mg/L): 0,097±0,017 (controle); 0,356±0,037; 0,779±0,141; 1,459±0,185 e 1,770±0,070 e quatro níveis de dureza (em mg CaCO3/L): 34,5±4,4; 62,0±5,7; 116,0±9,3 e 174,0±22,42. No experimento para avaliar a eficácia da adição de Ca2+ na ração sobre a CL50-96h do O2, os juvenis (4,75±0,65g e 7,56±0,61cm) foram expostos a cinco níveis de O2 (em mg/L): (0,41±0,13; 0,71±0,15; 0,97±0,13; 1,44±0,35 e 6,41±0,60 mg/L) e quatro níveis de Ca2+ na dieta (em % Ca2+): 0,45; 0,95; 1,45 e 2,45. Para verificar a eficácia do Ca2+ na água sobre a CL50-96h do O2, os juvenis (3,66±0,75g e 7,2±0,5cm) foram mantidos em cinco níveis de O2 (mg/L): 0,27±0,10; 0,74±0,26; 1,33±0,14; 1,74±0,32 e 6,55±0,02 mg.L-1) e quatro níveis de dureza (em mg CaCO3/L): (28, 116, 116 e 180). Para verificar a influência do Ca2+ na água sobre a sobrevivência e o crescimento, os juvenis (2,27±0,14g e 6,9cm) foram mantidos em dois níveis de NH3 (mg/L), 0,021±0,001 e 0,623±0,039, e quatro níveis de dureza na água (mg CaCO3/L): 32,1±4,6; 63,1±5,9; 119,9±10,0 e 177,3±8,1 por 40 dias. No segundo experimento de crescimento, os juvenis (3,66±0,75g e 7,32±0,5cm) foram mantidos dois níveis de O2 (1,47±0,04 e 6,46±0,06 mg/L), e quatro níveis de dureza na água (mg CaCO3/L): 30±2,0; 61±2,5; 121±3,0 e 180±3,0 por 15 dias. A CL50-96h para NH3 foi de 0,73 mg.L-1 (CI 0,63 0,84) no experimento com Ca2+ na dieta, com uma diferença significativa nos juvenis alimentados com 0,45 e 0,95% de Ca2+ na dieta. A dureza na água não influenciou a LC50-96h NH3, que foi de 1,20 mg/L (CI 1,10 - 1,24). No experimento para avaliar a influência dos níveis de NH3 no crescimento, o ganho de peso, biomassa e taxa de crescimento específico foram significativamente maiores nos juvenis expostos ao nível mais baixo de NH3 , do que naqueles mantidos no nível mais alto de NH3. Nesse experimento o aumento da dureza prejudicou os juvenis expostos ao nível mais baixo de NH3, mas o aumento beneficiou os juvenis mantidos no nível mais alto de NH3 em todos os parâmetros avaliados. A CL50-96h para o O2 foi de 0.89 mg/L (CI 0,64 1,34 mg/L) no experimento com Ca2+ na dieta e foi maior nos juvenis alimentados com 2.45 e 0.45% de Ca2+ na dieta. O ganho de peso, a biomassa, o comprimento e a taxa de crescimento específico foram significativamente maiores nos juvenis mantidos nas concentrações de 1,47±0,04 mg/L O2 do que os expostos a 6,46±0,06 mg/L O2. O aumento da dureza foi positivo para todos os parâmetros medidos nos juvenis expostos ao nível mais baixo de O2, mas prejudicou aqueles submetidos ao nível mais alto de O2. Este estudo indicou que dietas com baixos níveis de Ca2+ aumentam a sobrevivência de juvenis de jundia expostos a altos níveis de NH3 e baixas concentrações de O2, e ao aumento da dureza da água pode ser recomendada somente quando essa espécie é submetida a situações de hipóxia e altos níveis de NH3.

The current research was developed in Bahia of Jaramijó in the Province of Manabí during 2008, as part of the major project: " Characterization of the Ecuadorian Coast" that has been developing by INOCAR, in order to contribute to the proper use of resources and the environment. It characterized and assesses the results obtained in the research of the quality of water of Bahía of Jaramijó, taking into consideration the averages and their behaviour in each level studied in two different season in the year (wet-dry) and in two tide condition (ebb and flow) of the different parameter physical, chemical and microbiological. During the research was established that coastal marine waters of Bahía of Jaramijó, not show pollution of organic origin neither significant risk to the ecosystem as their chemical characteristics and microbiological showed good oxygenation that is related directly with low concentration of DBO5, acceptable ranks of pH, nearly nitrite absence, relatively low values of phosphate and nitrate except for silicate that showed the highest concentration in dry period which was probably related wit the abundance of cellular biomass specifically of the Coscinodiscus excentricus species. Bacterial load (total coliform and faecal) not reported microorganism pathogen contamination problems, except for a very specific site where was registered concentration above the permissible level, established in the Ecuadorian Environmental Legislation. Despite it evidence the presence of dissolved and dispersed hydrocarbon from petroleum (HDD) in dry period during the flow, such concentrations are below the permissible level established in UNESCO standard 1976, causing no pollution problems of this kind of pollutant. | La presente investigación se desarrolló en la Bahía de Jaramijó de la Provincia de Manabí durante el año 2008, como parte del macro proyecto "Caracterización de la Costa Ecuatoriana" que viene desarrollando el INOCAR, con la finalidad de contribuir en el uso adecuado de los recursos y el medio ambiente. Se caracteriza y evalúa los resultados obtenidos en el estudio de calidad de agua de la Bahía de Jaramijó, tomando en consideración los promedios y su comportamiento en cada nivel estudiado en las dos épocas del año (húmeda - seca) y en los dos estados de marea (flujo - reflujo) de los diferentes parámetros físicos, químicos y microbiológicos. Durante el estudio se estableció que, las aguas marino costera de la Bahía de Jaramijó, no presentan contaminación de origen orgánica ni peligro significativo al ecosistema ya que sus características químicas y microbiológicas mostraron buena oxygenación lo que está relacionado directamente con las bajas concentraciones de DBO5, rangos aceptables del pH, casi ausencia de nitrito, valores relativamente bajos de fosfato y nitrato a excepción del silicato que mostró las mayores concentraciones en la época seca lo que probablemente estuvo relacionado con la abundancia de la biomasa celular específicamente de las especies Coscinodiscus excentricus. La carga bacteriana (Coliformes totales y fecales) no reportó problemas de contaminación por microorganismos patógenos, a excepción de un sitio muy puntual donde se registraron concentraciones superiores al nivel permisible establecido en la Legislación Ambiental Ecuatoriana. A pesar de que se evidencia la presencia de Hidrocarburos Disueltos y Dispersos del Petróleo (HDD) en la época seca durante el flujo, tales concentraciones se encuentran muy por debajo del nivel permisible establecido en la norma UNESCO 1976, no ocasionando problemas de contaminación de este tipo de contaminante. | Published

As a result of pumping in excess of recharge, water levels in alluvial aquifers within the Eastern San Joaquin Groundwater Subbasin, 130 km east of San Francisco (California, USA), declined below sea level in the early 1950s and have remained so to the present. Chloride concentrations in some wells increased during that time and exceeded the US Environmental Protection Agency’s secondary maximum contaminant level of 250 mg/L, resulting in removal of some wells from service. Sources of high-chloride water include irrigation return in 16 % of sampled wells and water from delta sediments and deeper groundwater in 50 % of sampled wells. Chloride concentrations resulting from irrigation return commonly did not exceed 100 mg/L, although nitrate concentrations were as high as 25 mg/L as nitrogen. Chloride concentrations ranged from less than 100–2,050 mg/L in wells affected by water from delta sediments and deeper groundwater. Sequential electromagnetic logs show movement of high-chloride water from delta sediments to pumping wells through permeable interconnected aquifer layers. δD and δ¹⁸O data show most groundwater originated as recharge along the front of the Sierra Nevada, but tritium and carbon-14 data suggest recharge rates in this area are low and have decreased over recent geologic time. Managed aquifer recharge at two sites show differences in water-level responses to recharge and in the physical movement of recharged water with depth related to subsurface geology. Well-bore flow logs also show rapid movement of water from recharge sites through permeable interconnected aquifer layers to pumping wells.

Managed aquifer recharge (MAR) refers to intentional infiltration of surface water to an aquifer for facilitating natural water treatment and storage. MAR is often used as a treatment to remove natural organic matter from water in drinking water production. The sustainability of MAR depends on how the aquifer capacity to remove organic matter will evolve over the long term. This report explores the behavior of MAR systems by using a natural lake–aquifer system as a surrogate. Natural infiltration of lake water to groundwater has been going on for millennia at the research site in Finland chosen for this study. According to the measurements, the mean concentration of total organic carbon (TOC) in lake water was 3.0 mg/L. Within the distance of 3 m from the lake bank (retention time 7–15 days), already 46% of TOC was removed. At greater distances along the flow paths within the aquifer, 80–90% of TOC was removed. The observed TOC removal in the aquifer was slightly higher than the reported values at MAR sites, indicating that MAR can be an effective solution to the problem of removing natural organic matter in the long term. Signs of accumulation of organic matter were not observed in the aquifer, which suggests that biodegradation was the main removal method, and the role of sorption was minor. Several processes had an impact on oxygen levels in the aquifer, which led to spatial and seasonal changes in the redox conditions and in the iron and manganese concentrations in groundwater.