Search results for " river"

Application of Magnetic Susceptibility Measurements for Identification of Technogenic Horizons in Soil Profiles on the Example of the Vistula River C…

2018

Studies on magnetic properties of soils have been recently applied in the soil environment quality monitoring in relation to basic physical and chemical properties. However, the issue of distribution of ferrimagnetic materials in particular genetic soil horizons, especially in altered soils, has not yet been considered in environmental studies. The main subject of the research was to evaluate a potential of magnetic susceptibility measurements as implements for supporting the soil classification through indication of particular distinctive genetic horizons in the soil profile. The study objects were soils whose formation was strictly conditioned by hydrotechnical regulations in the area of …

Linking the Molecular Signature of Heteroatomic Dissolved Organic Matter to Watershed Characteristics in World Rivers

2015

Large world rivers are significant sources of dissolved organic matter (DOM) to the oceans. Watershed geomorphology and land use can drive the quality and reactivity of DOM. Determining the molecular composition of riverine DOM is essential for understanding its source, mobility and fate across landscapes. In this study, DOM from the main stem of 10 global rivers covering a wide climatic range and land use features was molecularly characterized via ultrahigh-resolution Fourier-transform ion cyclotron resonance mass spectrometry (FT-ICR-MS). FT-ICR mass spectral data revealed an overall similarity in molecular components among the rivers. However, when focusing specifically on the contributi…

Non-uniform Sediment Transport Estimation in Non-equilibrium Situations: Case Studies

2014

Abstract Quantitative estimate of sediment transport in alluvial channels is one of the most important task in river engineering. Even today, numerical models of sediment transport processes are confronted with some difficulties, often of conceptual nature. One of these difficulties is the simulation of non-uniform sediment transport in non-equilibrium situations, which requires the characterization of the ability of the alluvial system to immediately overcome the variations of the sediment boundary conditions. In this work a 1-D numerical model, which includes a new expression of the so-called “adaptation coefficient”, has been applied to test its capability to simulate the transient bed p…

Examen de las dinámicas socio-ecológicas en el valle medio del Xuquer (Valencia) desde el Paleolítico Medio hasta el Calcolítico

2017

En paisajes intensamente modificados por terrazas agrícolas y otros usos modernos del suelo, el patrón espacial y temporal del poblamiento prehistórico puede ser difícil de detectar usando métodos de prospección arqueológica tradicionales orientados a la localización de yacimientos part iculares. El abancalamiento del territorio para su explotación agrícola es norma común en el área de trabajo, por lo que es necesario examinar el paisaje en su conjunto, en lugar de intentar localiza r zonas concretas de actividad ant rópica prehistórica. Para superar estos desafíos, se ha empleado una estrategia estratificada, seleccionando aleato ria me nte las parcelas a prospectar, para examinar las diná…

Dissolved silica in the Garonne River waters : changes in the weathering dynamics

2000

The major ion chemistry of the Garonne River is indicative of seasonal variations in the weathering dynamics of the drainage basin. Using the geochemical model MEGA for calculation of the contribution of atmospheric CO2 to the total bicarbonate fluxes exported by the Garonne River allows estimations of the concentrations of the major dissolved elements that originate from silicate- and carbonate-rock weathering. The molecular ratio SiO2/Al2O3 was calculated for the 1989–1992 period to identify the main type of weathering in the Garonne River, and montmorillonite was shown to be the major mineral occurring in the weathering products. The seasonal variations of the SiO2/Al2O3 ratio also showe…

La ficción más grande: la poesía de Cristina Rivera Garza

2016

International audience

Las Formas Intranquilas. Poética transgenérica y sampleo literario en la escritura de Cristina Rivera Garza

2015

International audience

Nonuniform sediment transport estimation in non-equlibrium situations: study cases

2014

Molecular Signatures of Biogeochemical Transformations in Dissolved Organic Matter from Ten World Rivers

2016

Rivers carry large amounts of dissolved organic matter (DOM) to the oceans thereby connecting terrestrial and marine element cycles. Photo-degradation in conjunction with microbial turnover is considered a major pathway by which terrigenous DOM is decomposed. To reveal globally relevant patterns behind this process, we performed photo-degradation experiments and year-long bio-assays on DOM from ten of the largest world rivers that collectively account for more than one-third of the fresh water discharge to the global ocean. We furthermore tested the hypothesis that the terrigenous component in deep-sea DOM may be far higher than biomarker studies suggest, because of the selective photochemi…

Conservation of the Giant Freshwater Pearl Mussel (Pseudunio auricularius = Margaritifera auricularia Spengler, 1793) in Spain

2023

Las almejas de agua dulce o náyades son uno de los grupos faunísticos más amenazados del planeta. Entre ellos, la almeja gigante del Ebro o náyade auriculada (Pseudunio auricularius, Spengler 1793) es el bivalvo unionido más amenazado de Europa, y la población de la cuenca del río Ebro en España se encuentra en una situación crítica. El objetivo de esta tesis es aumentar el conocimiento científico del estado de conservación actual de la especie en España con el fin de aplicar acciones de gestión significativas para reducir su riesgo de extinción. El descenso de las poblaciones de náyades (Orden Unionida) en la cuenca del Ebro es generalizado, pero la situación en los canales asociados es cr…