Zaragoza, Spain
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Petrovic M.,Catalan Institution for Research and Advanced Studies | Ginebreda A.,IDAEA | Acuna V.,ICRA | Batalla R.J.,UdL CTFC | And 13 more authors.
TrAC - Trends in Analytical Chemistry | Year: 2011

Water resources are directly and indirectly affected by anthropogenic activities (e.g., changes in land use) and natural factors (e.g., climate change), that is, global change. The Mediterranean basin is one of the most vulnerable regions of the world to global change, and one of the " hot spots" for forthcoming problems of water availability. The present review provides an overview about the relationship between chemical quality (especially concerning organic microcontaminants) and water scarcity, particularly in the Mediterranean area. We include an overview of environmental contaminants and analytical methodologies and consider the fate and the behavior of organic contaminants, and the effects of pollutants on ecosystems. © 2011 Elsevier Ltd.

Marlon J.R.,Yale University | Kelly R.,Neptune and Company | Daniau A.-L.,CNRS Laboratory of Oceanic Environments and Paleo-environments (EPOC) | Vanniere B.,University of Burgundy | And 14 more authors.
Biogeosciences | Year: 2016

The location, timing, spatial extent, and frequency of wildfires are changing rapidly in many parts of the world, producing substantial impacts on ecosystems, people, and potentially climate. Paleofire records based on charcoal accumulation in sediments enable modern changes in biomass burning to be considered in their long-term context. Paleofire records also provide insights into the causes and impacts of past wildfires and emissions when analyzed in conjunction with other paleoenvironmental data and with fire models. Here we present new 1000-year and 22000-year trends and gridded biomass burning reconstructions based on the Global Charcoal Database version 3 (GCDv3), which includes 736 charcoal records (57 more than in version 2). The new gridded reconstructions reveal the spatial patterns underlying the temporal trends in the data, allowing insights into likely controls on biomass burning at regional to global scales. In the most recent few decades, biomass burning has sharply increased in both hemispheres but especially in the north, where charcoal fluxes are now higher than at any other time during the past 22000 years. We also discuss methodological issues relevant to data-model comparisons and identify areas for future research. Spatially gridded versions of the global data set from GCDv3 are provided to facilitate comparison with and validation of global fire simulations. © Author(s) 2016. CC Attribution 3.0 License.

Gonzalez-Sanchis M.,IPE CSIC | Murillo J.,University of Zaragoza | Latorre B.,University of Zaragoza | Comin F.,IPE CSIC | Garcia-Navarro P.,University of Zaragoza
Journal of Hydraulic Engineering | Year: 2012

The application of a two-dimensional (2D) finite volume numerical model to real flood events in the Ebro River is presented. The hydraulic model used is based on the 2D transient shallow-water equations on the irregular bed that are able to compute flow advance over a dry bed. This study involves the reliable simulation of not only the flood wave advance but also the drying process in a series of events of different magnitude. The importance of the correct characterization of the roughness coefficient and the topography is emphasized in the study. The former is estimated from a previous classification of structurally homogeneous habitats, and the latter is defined by merging the digital terrain model data with a hydraulic river bed elevation reconstruction algorithm. The calibration of the full model resulting from the roughness, bed river, and flow simulation models is based on field measurements of the flooded area for two steady discharges. The validation is performed by comparing the numerical results with the water levels measured during five flood events at certain times, with the flooded area and time series of continuous point measurements of water depth during different situations throughout the year. Because the model provides correct predictions of the surface processes both for low and high flow discharges, the simulation results are used to analyze the present floodplain hydrodynamics. In the same way, different topographic scenarios, on the basis of changes in the hydraulic riverfloodplain connectivity, are generated to analyze their potentially beneficial effect in the floodplain geomorphic dynamics. © 2012 American Society of Civil Engineers.

Moussaid B.,Moulay Ismaï University | El Ouardi H.,Moulay Ismaï University | Casas-Sainz A.,University of Zaragoza | Villalain J.J.,University of Burgos | And 4 more authors.
Journal of African Earth Sciences | Year: 2013

The aim of this work is to study the Anisotropy of the Magnetic Susceptibility (AMS) in two Jurassic-Cretaceous synclines located in the northern border of the Central High Atlas (Morocco): the Aït Attab and Ouaouizaght basins. AMS is used in order to obtain the magnetic fabric and its relationship with the kinematic evolution of both basins. The tectonic evolution of the basins, still under discussion, is mostly considered as the result of inversion during Tertiary and perhaps since Bathonian, of extensional and/or strike-slip Jurassic basins. Both basins are filled with Upper Jurassic to Lower Cretaceous silts and sandstones, with less frequent marine marly limestones.The bulk magnetic susceptibility (km) generally shows higher values in the red facies (163.2 E-6 in AT and 168.6 E-6 in WZ) than in the yellowish marly limestones (97.88 E-6 in AT and 132 E-6 in WZ). Most sites show an oblate magnetic fabric. The rock magnetic analyses indicate that the main carrier of the magnetic susceptibility for the red facies is hematite, whereas in the yellowish facies there is a dominance of paramagnetic minerals. In both basins, the magnetic lineation (long axis of the ellipsoid, kmax axes) shows a predominant E-W direction. The overlapping of the stress fields during the Atlasic basins evolution, in both compressional and extensional regimes and hinder the straightforward interpretation of the magnetic fabrics. However, a coeval N-S compression during the times of sedimentation with an E-W transtension can explain the magnetic lineation found in many of the sites analyzed in the present work. There are also other less frequent directions of kmax axes (NE-SW and NW-SE) are interpreted as the result of local change of the stress field during the early extensional stage of basin formation. © 2013 Elsevier Ltd.

Lopez-Vicente M.,EEAD CSIC | Lana-Renault N.,University of La Rioja | Garcia-Ruiz J.M.,IPE CSIC | Navas A.,EEAD CSIC
Journal of Soils and Sediments | Year: 2011

Purpose: Sediment delivery from headwater catchments to reservoirs is a serious threat to reservoir sustainability and is a critical issue in Mediterranean environments where water resources are scarce. In this study we assessed the consequences of two landscape management scenarios (natural vegetation recovery and scrub clearance) on soil erosion and sediment yield. The results were analyzed in relation to predicted and measured rates of soil erosion and sediment yield, with the aim of promoting better management practices. Materials and methods: The study area was the Arnás River catchment (284 ha), which is located in the central Spanish Pyrenees; the area includes abandoned and poorly managed fields. The combination of the RUSLE and SEDD models of soil erosion and sediment delivery was evaluated in terms of its ability to predict annual rates of sediment yield, using field measurement data for seven water years at the gauging station. The consequences of natural plant succession in other areas of the Spanish Pyrenees and scrub clearance practices implemented by certain regional governments to increase grazing meadow areas and reduce the incidence of wildfires were spatially analyzed using GIS. The main sediment source areas were identified, and their specific and total sediment yields were calculated. Results and discussion: The predicted soil loss under existing conditions was 2.6 Mg ha-1 year-1, with 5% of the surface area affected by rates greater than 2 Mg. The measured sediment yield range was 69-534 Mg year-1. The maximum sediment yield detected was associated with an extraordinary debris flow. The predicted rates were strongly correlated to measured rates (Nash-Sutcliffe coefficient = 0.72). The main sources were alluvial deposits [specific sediment yield (SSY) = 51 Mg ha-1 year-1], bare soil (SSY = 12), unpaved trails (SSY = 11), lots (SSY = 4), and pastures (SSY = 1). Under a scenario of vegetation recovery, decreases of 3%, 17%, and 16% in soil loss and sediment delivery and yield (respectively) are predicted, whereas increases of 15%, 5%, and 2% are predicted following scrub clearance practices. Conclusions: Coupling the RUSLE and SEDD models enabled estimation of annual values of soil erosion and sediment delivery in monitored and unmonitored catchments of small and medium size, making this approach a useful tool for risk analysis. Management practices that combine fire-risk control, by the implementation of scrub clearance practices, with the effects of plant succession on sediment production are suggested as the best management strategy. © 2011 Springer-Verlag.

Rodriguez-Rodriguez L.,University of Oviedo | Jimenez-Sanchez M.,University of Oviedo | Dominguez-Cuesta M.J.,University of Oviedo | Rinterknecht V.,University of St. Andrews | And 3 more authors.
Quaternary Science Reviews | Year: 2014

New evidence in the NW region of the Iberian Peninsula (~42°N 6°W) of a glacial advance coeval with the global Last Glacial Maximum (LGM) of the Marine Isotope Stage 2 has been identified through a dataset of exposure ages based on 23 10Be concentration measurements carried out on boulder samples taken from a set of latero-frontal moraines. Results span the interval 19.2-15.410Beka, matching the last deglaciation period when Iberia experienced the coldest and driest conditions of the last 25ka, and are consistent with Lateglacial chronologies established in other mountain regions from SW Europe. The extent of the LGM stade identified in this work is similar to the local maximum ice extent stade recorded and dated as prior to 33ka using radiocarbon and optically stimulated luminescence. This work showcases how multiple-dating approaches and detailed geomorphological mapping are required to reconstruct realistic palaeoglacier evolution models. © 2013 Elsevier Ltd.

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