Persistence and intensity of soil water repellency from soils with andic properties from the Campania region (Southwest, Italy) under different forest types

Congreso celebrado del 2-6, julio, 2012, en Fiera del Levante, Bari, Italia.Soil water repellency (SWR) is a property of many soils that is getting more and more interesting for the scientific community, because of its consequences on soil erosion risk, runoff or infiltration rates and even plant ecology. The presence of hydrophobic organic acids released by roots and plant tissues, fungal activity, organic matter mineralization rates, or wildfires are considered the main causes of SWR. Some of the consequences of SWR are reduced soil infiltration rates, enhanced runoff flow and soil erosion. Significance of these effects depends upon the severity and spatial variability of SWR. SWR is often associated to vegetation types, although it cannot be assumed that certain species always induce water repellency under natural conditions. Because of resins, waxes and aromatic oils in their tissues, evergreen trees as eucalyptus and coniferous are usually associated with soil hydrophobicity, although it has been found also in a variety of soils, climates and vegetation types. But the relationship between water repellent soils and plant species is not always one-to-one. Soil properties as texture, aggregation, acidity, microbiome and other are also implied in the development of hydrophobicity. Regarding organic matter, several authors have reported inconsistent results after studying the relationship between soil organic matter content and SWR. A possible explanation for this is that quality of organic matter is more important than content. Consequently, it is necessary to investigate the role that organic matter content and properties play in the development of hydrophobicity in different soil and vegetation types. The objective of this research is the study the relationship between SWR and organic matter properties in andic soils from the Campania region (SW Italy) under different vegetation types.Peer reviewe

Modelling constraints on the emission inventory and on vertical dispersion for CO and SO₂ in the Mexico City Metropolitan Area using Solar FTIR and zenith sky UV spectroscopy

International audienceEmissions of air pollutants in and around urban areas lead to negative health impacts on the population. To estimate these impacts, it is important to know the sources and transport mechanisms of the pollutants accurately. Mexico City has a large urban fleet in a topographically constrained basin leading to high levels of carbon monoxide (CO). Large point sources of sulfur dioxide (SO2) surrounding the basin lead to episodes with high concentrations. An Eulerian grid model (CAMx) and a particle trajectory model (FLEXPART) are used to evaluate the estimates of CO and SO2 in the current emission inventory using mesoscale meteorological simulations from MM5. Vertical column measurements of CO are used to constrain the total amount of emitted CO in the model and to identify the most appropriate vertical dispersion scheme. Zenith sky UV spectroscopy is used to estimate the emissions of SO2 from a large power plant and the Popocatépetl volcano. Results suggest that the models are able to identify correctly large point sources and that both the power plant and the volcano impact the MCMA. Modelled concentrations of CO based on the current emission inventory match observations suggesting that the current total emissions estimate is correct. Possible adjustments to the spatial and temporal distribution can be inferred from model results. Accurate source and dispersion modelling provides feedback for development of the emission inventory, verification of transport processes in air quality models and guidance for policy decisions

Spatial analysis for assessing soil organic carbon stocks in southern Spain

Comunicación oral presentada al European Geosciences Union General Assembly 2012, que tuvo lugar del 22-27, abril, 2012, en Viena, Austria.The objectives of the present study were to estimate current soil organic carbon (SOC) stocks for each land use and soil type, studying relationships between SOC stocks and selected environmental variables (elevation, temperature and precipitation).Peer reviewe

¿Catástrofes ecológicas en la estepa? Arqueología del Paisaje en el complejo minerometalúrgico de Kargaly (Región de Orenburg, Rusia)

Kargaly is one of the most important centers of mining and metallurgy in the great Eurasian steppe. Dr. E.N. Chernykh and his team (Institute of Archaeology, Russian Academy of Sciences, Moscow) and various researchers at the CSIC and other Spanish institutions have developed a joint project to undertake a comprehensive study of the site's two main phases of occupation, the Bronze Age (2nd millenium BC) and the first Russian industrialization (1745-1900 AD). The Russian members of the joint team are in charge of the archaeological investigations, while the Spanish members are studying metallurgical and mining technology and production, on the one hand, and the environmental context and impact of these activities, on the other. This article presents the research design and first results of the Palaeoenvironmental research at Kargaly. This work has two aspects. The first consisted of obtaining one of the most complete palaeoenvironmental data sets from the steppes through both the systematic sampling of archaeological sites to recover charcoal, seeds, fruits and pollen and the taking of palynological cores from natural deposits, on the other Both sampling programs were supported by radiocarbon dates. The second aspect, to which the greater part of this article is devoted, was dedicated to contextualizing the palaeobotanical evidence by studying the present-day landscape, with particular attention to understanding the processes which shape the variability of the pollen rain. Our purpose was to obtain explicit and measurable calibrative criteria which would enable us to answer the palaeoenvironmental questions raised by our archaeological and archaeometallurgical research. These questions include, most importantly, the following: what was the extent of forest (the energy base for the mining/metallurgical complex) during the Bronze Age? and how do we evaluate subsistence practices? (an issue related to the origins of agriculture on the steppe). Answering both questions require us to go beyond conventional palaeoenvironmental practice, since they require very specific information about the past spatial distribution of vegetation on both local and regional scales. We propose a methodological perspective that places the practice of palynology in archaeology within the goals, theoretical premisses, and methods of Landscape Archaeology. Using this framework we evaluate and identify the limitation of conventional palaeoenvironmental practice (particularly the use of pollen analysis in archaeology) and we develop an intensive application of model-based approach to palynology, one that combines study of the pollen rain with mathematical modelling of the landscape. To put it into practice we used modern methods of terrestrial observation, such as satellite imagery, grounded in the use of Geo graphical Information Systems (GIS) and global positioning (GPS) technology.Kargaly es uno de los centros de minería y metalurgia del cobre más significativos de la Gran Estepa Euroasiática. El Dr. E.N. Chernyj y su equipo (Instituto de Arqueología, Academia Rusa de Ciencias, Moscú) y varios investigadores del CSIC y de otras instituciones españolas desarrollan allí un proyecto conjunto para el estudio integral de sus dos fases de explotación: la Edad del Bronce (II milenio AC) y la primera industrialización rusa (1745-1900 AD). Los miembros rusos del equipo están a cargo de la investigación arqueológica de este proyecto coordinado y los miembros españoles del estudio de los aspectos tecnológicos y productivos de la minería y la metalurgia, por un lado, y del contexto ambiental de ambas actividades, así como de su impacto sobre el territorio por otro. El propósito de este artículo es presentar los planteamientos y primeros resultados del programa de estudios paleoambientales, que consta de dos fases. La primera dio lugar a uno de los registros paleoambientales más completos de esta región mediante muestreo sistemático antracológico, paleocarpológico y palinológico en varios yacimientos arqueológicos, y sondeos palinológicos en depósitos naturales. En ambos casos se contó con el apoyo de dataciones radiocarbónicas. La segunda fase, a la que se dedica la mayor parte del artículo, se orientó a la contextualización de ese registro mediante una investigación sobre el paisaje actual, con especial énfasis en la comprensión de los procesos de formación de la lluvia polínica. Su finalidad es obtener criterios explícitos y controlables de calibración para la interpretación de las cuestiones paleoambientales demandadas por la investigación arqueológica y arqueometalúrgica. Destaca entre ellas la evaluación de los recursos forestales durante la Edad del Bronce, base energética del complejo minero metalúrgico, y el problema del reconocimiento de las prácticas subsistenciales, en relación con la discusión sobre el comienzo de la economía productora en la Gran Estepa Euroasiática. Ambas rebasan el marco de la práctica paleoambiental convencional, al requerir información muy específica sobre la distribución espacial en el pasado de la vegetación a escala local y regional. Se propone un enfoque metodológico que enmarca la práctica de la palinología arqueológica en los objetivos, planteamientos teóricos y métodos de la Arqueología del Paisaje. Desde este marco se evalúan y diagnostican las limitaciones de la práctica convencional de la Arqueología paleoambiental (particularmente la palinología arqueológica) y se ofrece una aplicación intensiva del "enfoque modelizador" en paleopalinología basada en la combinación de métodos de modelización matemática del paisaje y de la lluvia polínica. Para su puesta en práctica se aplican métodos avanzados de observación de la Tierra, como la Teledetección espacial, apoyados en el uso intensivo de la tecnología de los Sistemas de Información Geográfica (GIS) y las técnicas de posicionamiento global (GPS)

Patterns and drivers of tree Mortality in Iberian Forests: climatic effects are modified by competition

Tree mortality is a key process underlying forest dynamics and community assembly. Understanding how tree mortality is driven by simultaneous drivers is needed to evaluate potential effects of climate change on forest composition. Using repeat-measure information fromc.400,000 trees from the Spanish Forest Inventory, we quantified the relative importance of tree size, competition, climate and edaphic conditions on tree mortality of 11 species, and explored the combined effect of climate and competition. Tree mortality was affected by all of these multiple drivers, especially tree size and asymmetric competition, and strong interactions between climate and competition were found. All species showed L-shaped mortality patterns (i.e. showed decreasing mortality with tree size), but pines were more sensitive to asymmetric competition than broadleaved species. Among climatic variables, the negative effect of temperature on tree mortality was much larger than the effect of precipitation. Moreover, the effect of climate (mean annual temperature and annual precipitation) on tree mortality was aggravated at high competition levels for all species, but especially for broadleaved species. The significant interaction between climate and competition on tree mortality indicated that global change in Mediterranean regions, causing hotter and drier conditions and denser stands, could lead to profound effects on forest structure and composition. Therefore, to evaluate the potential effects of climatic change on tree mortality, forest structure must be considered, since two systems of similar composition but different structure could radically differ in their response to climatic conditions