Erosional processes in rocky and sedimentary coasts

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Degradation of a transgressive coastal Dunefield by pines plantation and strategies for recuperation (Lagoa Do Peixe National Park, Southern Brazil)

The transgressive dunefield of the Lagoa de Peixe Natural Park was modified drastically due to intensive pine plantation and the leeward development of the associated degraded areas. The present study analyzed the disturbances in the dunefield of the Lagoa do Peixe Natural Park due to pine tree plantation and the impact of the subsequent deforestation program conducted in the region. Aerial photographs, satellite images, and DGPS topographic data collected over a 70-year-long period were retrieved, analyzed, and compared, which allowed the observation of the geomorphological evolution of the dunefield. In addition, a profile of GPR on the inlet (during a period with the channel closed) was analyzed. In 1948, the surface of the sand barrier was occupied by high transverse dunes and low barchan dunes. Pine tree plantation on the inner side fixed the transgressive dunes and, consequently, avoided the filling of the shallow lagoon, although degraded areas were generated on the lee side of the pines. Simultaneous pine plantations in the backshore avoided the aeolian sediment input to the dunefield, generating a large interdune area along with the development of a few parabolic dunes, which resulted in cannibalization of the transgressive dunes. In 2001, pine trees occupied 15.03% of the total area analyzed in the present study, while the degraded area accounted for 10.81% of the total area. Progressive deforestation was performed (ring bound technique for tree gradual death), maintaining three lines of pines in contact with the dunes, to promote autochthonous vegetation growth, thereby preventing the filling of the adjacent lagoon with aeolian sediments. By the year 2018, the pine tree plantation area reduced to 3.25%, the dunefield area was 79.03%, and the extension of the degraded areas had increased and reached 17.71% of the total area. The pine tree plantation and the deforestation for conservation purposes are the main factors explaining the degradation of the dunefield during the period between 1948 and 2018, while regional climatic oscillations contributed as the secondary factor. Although internationally controversial, the present case study demonstrates that the removal of this exotic vegetation, through dune vegetation recovery programs, is often unsuccessful and may generate more degraded areas. However, in the case presented here, it was essential to remove the forest to ensure the dune field geodynamics and, therefore, the base (biotope) of the natural system (maintenance of the lagoon and the dunefield)

Implementación de radioterapia estereotáxica torácica en un hospital terciario: resultados preliminares

La RT estereotáxica extracraneal (SBRT) es el tratamiento de elección para pacientes con carcinoma de pulmón no microcítico (CPNM) en estadios iniciales (T1-2N0M0) inoperables o que rechazan ser intervenidos, y es una alternativa a la cirugía para pacientes de alto riesgo quirúrgico. Mediante SBRT torácica se administran altas dosis de radiación en muy pocas fracciones, sobre un volumen pulmonar relativamente pequeño. La pérdida de exactitud en su administración provoca drásticos cambios en la posibilidad de cura y toxicidad. Exige por tanto una cuidadosa planificación y administración del tratamiento, teniendo en cuenta el movimiento respiratorio. Su alta eficacia y baja toxicidad ha motivado que su implementación crezca de forma exponencial. 2 OBJETIVO Implementar la SBRT torácica en el Hospital Clínico San Carlos de Madrid (HCSC) para el tratamiento de pacientes con CPNM en estadio inicial, y para nódulos pulmonares sin diagnóstico histológico pero con alta probabilidad de malignidad, sin tumor activo extratorácico. Se describen los protocolos diseñados para su implementación, adaptados a las características del HCSC. Para evaluar la técnica implementada se han analizado los siguientes objetivos secundarios en los primeros 20 tratamientos: precisión en el control del movimiento tumoral, toxicidad aguda y subaguda, impacto del tratamiento en la calidad de vida, y cambios morfo-funcionales en la 18F-FDG PET/TC realizada a las 24-96 horas y a las 8-10 semanas tras finalizar el tratamiento, frente a los parámetros basales en la 18F-FDG PET/TC de planificación..

Combined beach - inner shelf erosion in short and medium term (Maspalomas, Canary Islands)

The analysis of the accurate topo-bathymetric digital elevation model (DEM), the cartography of the submarine sedimentary cover and the monitoring of short (seasonal) and medium-term (2000-2009) morphological changes have permitted depicting the erosional trend in the short and medium-term of the Maspalomas sedimentary system. Short-term analysis showed intense sedimentary fluxes between the beaches and the inner shelf, and sedimentary exchanges with other sectors of the inner shelf, while the steep slope inner shelf fronting La Bajeta cape was identified as a sink area. In the medium-term the sediment budget showed high erosion of the supratidal and intertidal sectors of the beaches due to storm waves in the 2005-2006 winter, followed by accretion over the next four years, but which did not reach the initial sedimentary state. The inner shelf and subtidal sector of the beaches showed negative budgets in the short and medium-term. Interannual variability of the wave and wind regimes determines decadal beach erosion-accretion cycles, while long-term climatic change, evidenced at the study area by a decrease of trade winds and NE wave intensity in 2005, is expected to produce a possible increase of erosion at the El Inglés inner shelf and consequently a decrease in sediment inputs to the El Inglés beach and Maspalomas dune field. Finally, the influence of the geological heritage is depicted by the Fataga gully’s control of the present coastal morphology, and by the island relief control of the wind, waves and current directions in the study area

Human disturbances of shoreline morphodynamics and dune ecosystem at the Puerto Velero spit (Colombian caribbean)

Evolution of present coastal environments is controlled by both natural processes and anthropogenic activities, last one causing global, regional and local disturbances. This study analyze the effects of shortage of sediments from Magdalena River and tourism development in the recent shoreline morphodynamics and dune vegetation structure of the Puerto Velero spit, in the northern Colombian Caribbean coast. Shoreline position, dune vegetation and human occupation were taken from the interpretation of satellite images, aerial photographs and field trips. Three methods were applied to analyze shoreline migration. It allowed to deduce trends of very high erosion for the outer neck and moderate to high erosion for the inner neck, while the northern border and the point of the spit present an erosional trend in the outer and inner. Therefore, the outer neck and iner neck show predominance of an erosional trend, more intense for the outer one, while the northern border and particularly the point of the spit present trends of high and very high accretion. It implicates a present progradation of the spit, but a narrowing of its neck. The shortage of coastal sand due to the construction of a jettie at Magdalena River favored the formation of the spit by the erosion of the extinct Isla Verde barrier island, but currently cause erosion of the neck. Erosion of the outer and inner neck is also due to the impact of local disturbances on the backshore and dune system, mainly a rapid increase of occupation and a large circulation of people and vehicles. Dune vegetation distribution is affected by these disturbance, including the presence of invasive aloctonous Calotropis procera over a large area of the dune field. The natural climatic oscillations, particularly the negative El Niño Southern Oscillation (ENSO) events, also favor the progradation of the spit. The analysis of these disturbances on the present geomorphological and ecological evolution on the spit constitutes an important instrument for coastal management

Tasas de transporte de Ekman y afloramiento costero al noroeste de África a partir de la simulación numérica de campos de viento superficiales

La simulación del campo de vientos superficial en el océano, al noroeste de África, ha sido obtenida usando el modelo mesoescala de código abierto Weather Research and Forecasting (WRF). El rango espacio-temporal elegido para la simulación abarca la región de la Macaronesia central/norte (40º N, 20º W - 25º N, 5º W) durante un mes (noviembre del 2007). Para la ejecución eficiente de esta simulación en un escenario de recursos computacionales limitados ha sido necesario emplear las últimas técnicas en cálculo distribuido poliarquitectónico. Una vez obtenido el campo de vientos, se han derivado las corrientes superficiales debidas al esfuerzo del viento, el transporte de Ekman y los índices de afloramiento para toda la zona, para cada día y en media global. La validación cualitativa y cuantitativa de los resultados obtenidos ha sido realizada comparándola con estudios previos de teledetección realizados por otros grupos de investigación, así como con las simulaciones generadas a partir del modelo atmosférico RAMS. Este modelo ha sido empleado para la mismas condiciones espacio-temporales descritas anteriormente por el Centro de Estudios Ambientales del Mediterráneo (CEAM).We have run a computer simulation of the atmosphere processes and evolution in order to obtain the surface wind field over the ocean. To accomplish this task, we have made use of the mesoescalar open source atmospheric model Weather Research and Forecasting (WRF). The spatial and temporal ranges used for the simulation correspond to the month of November 2007 and the central/north Macaronesia (40N, 20W - 25N, 5W). For an efficient implementation of this simulation in a scenario of rather limited computational resources, it has been necessary to make use of the latest poly architecture distributed computing techniques. Once the wind field has been obtained, we have derived surface currents due to wind stress, Ekman transport and upwelling indices for the whole area, daily and global mean. We have qualitatively and quantitatively compared these results with experimental values derived by other research groups (using remote sensing tools). Finally we have also verified that the results are consistent with those obtained by the numerical model RAMS run for the same space-time conditions described above by the Centre for Mediterranean Environmental Studies (CEAM).Ciencias Experimentale

Dune System Restoration in Osório Municipality (Rio Grande do Sul, Brazil): Good Practices Based on Coastal Management Legislation

Dune Management Plans are useful tools to integrate coastal development, dune conservation and even dune restoration. The environmental legislation of Rio Grande do Sul (South of Brasil) establishes a Permanent Preservation Area of 60-m minimum width that should be protected in the coastal dune systems. This study shows the implementation of a coastal management plan in Osório Municipality (N of Rio Grande do Sul) for the restoration of the foredune. The analysis of previous evolution (1997–2010) of the dune field showed widths lower than the legal requirement and decreasing in the last years. Then, a dune restoration plan was designed and implemented in 2011. The measures included the planned retreat of the road located back the foredune, channelization of the northern whashout’s mouth with a structure under the foredune, installation of sand fences and control of the pedestrian accesses to the beach by both a pathway and a footbridge. Finally, efficiency of the management plan was assessed by monitoring (2011–2016) the foredune evolution, which permitted to conclude a satisfactory result. Only the foredune sector close to the washout’ mouth did not achieve the expected minimum width, but it can be considered acceptable considering its higher sedimentary dynamics, the inherent difficulties of these structures and the short monitoring period from the implementation of the plan

El efecto de exposición en el patrón sedimen- tario del sector submareal de tres playas en la Ría de Muros y Noia (NO de España)

En este trabajo se presenta la comparación de los sedimentos superficiales de la plataforma proximal de tres complejos playeros situados en las inmediaciones de la embocadura de la Ría de Muros y Noia. En cada uno de ellos, se han identificado las distintas poblaciones sedimentarias en función de los análisis granulométricos realizados. La aplicación de un análisis estadístico de componentes principales a las fracciones granulométricas, contenido en carbonatos y materia orgánica, ha permitido diferenciar poblaciones de muestras y la interpretación sedimentaria de las mismas. Las diferencias observadas en la distribución de las poblaciones sedimentarias de los tres complejos estudiados son una consecuencia del grado de exposición de cada complejo al oleaje dominante y de la presencia de afloramientos rocosos sumergidos que ejercen un efecto barrera.The subaquatic sediments from the inner continental shelf of three beach systems located in the surrondings of Ría de Muros y Noia mouth are compared. Different sedimentary populations have been stablished according to the granulometric distribution from each system. The grain-size distribution, carbonate and organic matter content have been compared by means of a principal component analysis. The results allow the identification of different populations as well as their sedimentary significance. The observed differences between the sedimentary populations from each system are explained as a consequence of their grade of exposure towards the dominant waves and the presence of subaquatic rocks, which introduce a barrier effect

Impact of terrestrial mining and intensive agriculture in pollution of estuarine surface sediments: Spatial distribution of trace metals in the Gulf of Uraba, Colombia

The Gulf of Uraba (northwestern Colombia) is a geostrategic region, rich in biodiversity and natural resources. Its economy is mainly based on agribusinesses and mining activities. In this research is determined the impact of these activities in bottom surface sediments of the estuary. Thus, grain size, total organic carbon, total nitrogen, carbonates, Ag, Al, Ca, Cr, Cu, Fe, Hg, Mg, Mn, Ni, Pb and Zn concentrations from 17 surface sediment samples were obtained and enrichment factors (EF) as well as geo-accumulation indices (Igeo) were calculated to determine the contamination level in the gulf. EF and Igeo values revealed that the estuary is extremely contaminated with Ag and moderately contaminated with Zn. Therefore, the observed enrichment of Ag may be explained as a residue of the extraction of gold and platinum-group metals and the enrichment with Zn associated mainly to pesticides used in banana plantations. (C) 2016 Elsevier Ltd. All rights reserved