CLIMATE CHANGE IMPACTS ON WATER RESOURCES

(1) Global changes in climate may have large impacts on regional water resources and the frequency of drought or ood events. Changes in precipitation or temperature may also severely modify the available water resources for users in several sectors. Here, we examine climate change scenarios for the Gallego river (a tributary of the larger Ebro river in Spain) in the context of quantitative water resources management for the basin. Projected changes to precipitation and temperature are derived from an ensemble of 6 Regional Climate Models (RCMs) run for the period 2071-2100 under the SRES A2 emissions scenario and are subsequently bias corrected before input into a hydrological model. The use of RCM ensembles is important for the incorporation of uncertainties derived from different model structures, parameterizations and boundary conditions into the hydrological modeling process and subsequent climate change impact assessment. All 6 RCMs project decreases in annual precipitation with some RCMs projecting a slight increase between December and February. Additionally, all models project a >3 � C increase in annual mean temperature over the basin, with some models projecting a 9 � C temperature increase during summer months. Hydrological simulations using the GEOTRANSF model, with the climate change scenarios as input, show that projected water availability for the Gallego is lower for the 2071-2100 period than for 1961-1990, with an increasing number of dry years. During the water-storage period (October to March), medium to low ows are reduced, while during the irrigation period (April to September), streamow is reduced across the entire range of ows. The projected changes vary across the basin and are also not uniform throughout the year. Stronger drying occurs during the summer with potentially important implications for water resource management across many sectors including agriculture, with a reduction in the amount of water available for irrigation and hydropower generation, due to projected seasonal reductions in reservoir levels

A time-dependent multi-layered mathematical model of filtration and solute exchange, the revised Starling principle and the Landis experiments

Cell oxygenation and nutrition is vitally important for human and animal life. Oxygen and nutrients are transported by the blood stream and cross microvessel walls to penetrate the cell's membrane. Pathological alterations in the transport of oxygen, and other nutrition elements, across microvessel walls may have serious consequences to cell life, possibly leading to localized cell necrosis. We present a transient model of plasma filtration and solute transport across microvessel walls by coupling flow and transport equations, the latter being non-linear in solute concentration. The microvessel wall is modeled through the superimposition of two or more membranes with different physical properties, representing key structural elements. With this model, the combined effect of the endothelial cells, the glycocalyx and other coating membranes specific of certain microvessels, can be analyzed. We investigate the role of transient external pressures in the study of trans-vascular filtration and solute exchange during the drop of blood capillary pressure due to the pathological decrease of blood volume called hypovolaemia, as well as hemorrhage. We discuss the advantage of using a multi-layered model, rather than a model considering the microvessel wall as a single and homogeneous membrane

Combining next-generation pyrosequencing with microarray for large scale expression analysis in non-model species

<p>Abstract</p> <p>Background</p> <p>The next generation sequencing technologies provide new options to characterize the transcriptome and to develop affordable tools for functional genomics. We describe here an innovative approach for this purpose and demonstrate its potential also for non-model species.</p> <p>Results</p> <p>The method we developed is based on 454 sequencing of 3' cDNA fragments from a normalized library constructed from pooled RNAs to generate, through <it>de novo </it>reads assembly, a large catalog of unique transcripts in organisms for which a comprehensive collection of transcripts or the complete genome sequence, is not available. This "virtual transcriptome" provides extensive coverage depth, and can be used for the setting up of a comprehensive microarray based expression analysis. We evaluated the potential of this approach by monitoring gene expression during berry maturation in <it>Vitis vinifera </it>as if no other sequence information was available for this species. The microarray designed on the berries' transcriptome derived from half of a 454 run detected the expression of 19,609 genes, and proved to be more informative than one of the most comprehensive grape microarrays available to date, the GrapeArray 1.2 developed by the Italian-French Public Consortium for Grapevine Genome Characterization, which could detect the expression of 15,556 genes in the same samples.</p> <p>Conclusion</p> <p>This approach provides a powerful method to rapidly build up an extensive catalog of unique transcripts that can be successfully used to develop a microarray for large scale analysis of gene expression in any species, without the need for prior sequence knowledge.</p

Assessing the effects of hydrological and chemical stressors on macroinvertebrate community in an Alpine river: the Adige river as a case study

In this study, the combined effects of hydrological and chemical stressors on benthic macroinvertebrates were evaluated in order to explore the response of the biological community to multiple stressors. The Adige River, located in the south‐eastern Alps, was selected as a case study because representative of the situation of a large river in which the variety of stressors present in the Alpine region act simultaneously. As expected, streamflow showed a seasonal pattern, with high flows in the spring-summer period; however, locally, the natural hydrological regime was altered by the presence of hydropower systems, which chiefly affected low flows. Multivariate analysis showed seasonal and spatial patterns in both chemical and hydrological parameters with a clear gradient in the concentration of nitrate, personal care, and pharmaceutical products moving from headwaters to the main stem of the river. The macroinvertebrate community composition was significantly different in summer and winter and between up and downstream sites. Streamflow alteration chiefly due to water use by hydropower affected community composition but not richness or diversity. Gammarus sp., Hirudinea, and Psychomyia sp., were positively correlated with flow variability, increasing their densities in the sites with higher streamflow variability because of hydropeaking. The results obtained in this study show that the composition of the macroinvertebrate community responded to seasonality and to changes in the main stressors along the river and highlights the importance of the spatial and temporal variability of stressors in this Alpine river. Taking into account, this variability will help the decision‐making process for improving basin management

Utjecaj induciranog tranzijentnog toka na transport u prirodnim vodonosnicima

In situ remediation is an effective technique to reduce risk caused by contaminated aquifers. However, low groundwater-flow velocity – typical in natural aquifers – hinders dilution, thereby reducing remediation efficiency. A possible strategy to overcome this problem consists of forcing the flow field by means of a geo-engineered system of alternate pumping. This work is aimed at investigating the coupled effect of geo-engineered unsteady flow and natural aquifer heterogeneity on remediation. Here we introduce an innovative analytical formulation to quantify dilution in 3D heterogeneous porous media under the effect of alternate pumping. Our solution relies on a simplified first-order framework, which limits the solution to point-like sources, weakly heterogeneous media, and slowly oscillating transient flows. Our results indicate that the efficiency of the unsteady flow field is mostly ruled by local-scale dispersion. Furthermore, we analyze several schemes of alternate pumping, thereby showing that inducing a forced rotation in the mean trajectory enhances remediation efficiency.Sanacija podzemnih voda je uspješna metoda smanjivanja rizika uzrokovanog zagađenim vodonosnicima. Prirodni vodonosnici su obilježeni malim brzinama podzemne vode što otežava razrjeđivanje, a time i efikasnost procesa sanacije. Navedeni problem se potencijalno može riješiti prisilnim protjecanjem ako se uvede sustav izmjeničnog utiskivanja. U ovom radu će se istražiti povezani utjecaj takvog projektiranog nestacionarnog tečenja i prirodne heterogenosti vodonosnika na proces sanacije. Uveden je inovativni analitički pristup za procjenu razrjeđenja u 3D heterogenom poroznom mediju pod utjecajem izmjeničnog utiskavanja. Predloženo rješenje spada u klasu prvog reda, što ga ograničava na točkaste izvore, blago heterogeni medij i tranzijentne tokove sa sporim promjenama. Ostvareni rezultati su ukazali da je efikasnost polja nestacionarnog tečenja dominatno pod utjecaj disperzije na lokalnoj skali. Nadalje, analizirano je nekoliko različitih shema izmjeničnog utiskivanja, što je ukazalo da induciranje prisilne rotacije u srednjoj trajektoriji toka povećava efikasnost procesa sanacije

Functional genomic analysis of constitutive and inducible defense responses to Fusarium verticillioides infection in maize genotypes with contrasting ear rot resistance.

Background: Fusarium verticillioides causes ear rot in maize (Zea mays L.) and accumulation of mycotoxins, that affect human and animal health. Currently, chemical and agronomic measures to control Fusarium ear rot are not very effective and selection of more resistant genotypes is a desirable strategy to reduce contaminations. A deeper knowledge of molecular events and genetic basis underlying Fusarium ear rot is necessary to speed up progress in breeding for resistance. Results: A next-generation RNA-sequencing approach was used for the first time to study transcriptional changes associated with F. verticillioides inoculation in resistant CO441 and susceptible CO354 maize genotypes at 72 hours post inoculation. More than 100 million sequence reads were generated for inoculated and uninoculated control plants and analyzed to measure gene expression levels. Comparison of expression levels between inoculated vs. uninoculated and resistant vs. susceptible transcriptomes revealed a total number of 6,951 differentially expressed genes. Differences in basal gene expression were observed in the uninoculated samples. CO441 genotype showed a higher level of expression of genes distributed over all functional classes, in particular those related to secondary metabolism category. After F. verticillioides inoculation, a similar response was observed in both genotypes, although the magnitude of induction was much greater in the resistant genotype. This response included higher activation of genes involved in pathogen perception, signaling and defense, including WRKY transcription factors and jasmonate/ ethylene mediated defense responses. Interestingly, strong differences in expression between the two genotypes were observed in secondary metabolism category: pathways related to shikimate, lignin, flavonoid and terpenoid biosynthesis were strongly represented and induced in the CO441 genotype, indicating that selection to enhance these traits is an additional strategy for improving resistance against F. verticillioides infection. Conclusions: The work demonstrates that the global transcriptional analysis provided an exhaustive view of genes involved in pathogen recognition and signaling, and controlling activities of different TFs, phytohormones and secondary metabolites, that contribute to host resistance against F. verticillioides. This work provides an important source of markers for development of disease resistance maize genotypes andmay have relevance to study other pathosystems involving mycotoxin-producing fungi

Evaluation of genotoxic potential throughout the upper and middle stretches of Adige river basin

In this study a comprehensive genotoxicological survey throughout the upper and middle stretches of Adige river basin is presented. The study was carried out at 7 sites located along the Adige main course and one the most significant tributaries, the Noce creek, both presenting different levels of pollution pressure. To give an insight into the nature of the genotoxic activity we employed the battery of prokaryotic and eukaryotic assays. Mutagenicity in water samples was evaluated by SOS/umuC test in Salmonella typhimurium TA1535/pSK1002. The level of DNA damage as a biomarker of exposure (comet assay) and biomarker of effect (micronucleus assay) and the level of oxidative stress as well (Fpg - modified comet assay) were studied in blood cells of Salmo cenerinus Nardo, 1847 and Salmo marmoratus Cuvier, 1829. Within the applied bioassays, comet assay showed the highest potential for discriminating the sampling sites which are under lesser extent of pressure (sampling sites 1-Barnes at Bresimo and 4-Noce downstream S. Giustina) from the sites under high pressure (sampling sites 5-Noce at Mezzolombardo and 6/7-Adige upstream and downstream municipality of Trento). Significant correlation between the standard and Fpg - modified comet assay indicated that oxidative stress could be a major contributor to observed DNA damage in collected specimens

Particle bound pollutants in rivers: Results from suspended sediment sampling in Globaqua River Basins

Transport of hydrophobic pollutants in rivers such as polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs) and heavy metals is often facilitated by suspended sediment particles, which are typically mobilized during high discharge events. Suspended sediments thus represent a means of transport for particle related pollutants within river reaches and may represent a suitable proxy for average pollutant concentrations estimation in a river reach or catchment. In this study, multiple high discharge/turbidity events were sampled at high temporal resolution in the Globaqua River Basins Sava (Slovenia, Serbia), Adige (Italy), and Evrotas (Greece) and analysed for persistent organic pollutants such as PAHs (polycyclic aromatic hydrocarbons) or PCBs (polychlorinated biphenyls) and heavy metals. For comparison, river bed sediment samples were analysed as well. Further, results are compared to previous studies in contrasting catchments in Germany, Iran, Spain, and beyond. Overall results show that loadings of suspended sediments with pollutants are catchment-specific and relatively stable over time at a given location. For PAHs, loadings on suspended particles mainly correlate to urban pressures (potentially diluted by sediment mass fluxes) in the rivers, whereas metal concentrations mainly display a geogenic origin. By cross-comparison with known urban pressure/sediment yield relationships (e.g. for PAHs) or soil background values (for metals) anthropogenic impact – e.g. caused by industrial activities – may be identified. Sampling of suspended sediments gives much more reliable results compared to sediment grab samples which typically show a more heterogeneous contaminant distribution. Based on mean annual suspended sediment concentrations and distribution coefficients of pollutants the fraction of particle facilitated transport versus dissolved fluxes can be calculated