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125

Project log

José Noel Pérez-Asensio
added a research item
Here we developed and validated a new Benthic Foraminiferal Salinity (BFS) index from marginal-marine environments by analysing benthic foraminifera from the Holocene Guadalquivir estuary sediments (SW Spain). This index is formulated utilising only four species: Ammonia tepida and Haynesina germanica with higher tolerance to brackish waters and indicating lower salinity, and Elphidium translucens and Elphidium granosum indicative of greater marine influence and pointing to higher salinity. Thus, the BFS index is calculated easily and rapidly, and therefore it makes it possible to analyse a higher number of samples in less time. The BFS index values from the studied cores enabled the detailed description of subtle changes in the Guadalquivir estuary restriction during the Holocene. For this purpose, three degrees of salinity, depending on marine influence, were defined: higher (BFS index = 0.0–0.4, high marine influence), moderate (BFS index = 0.4–0.7, moderate marine influence), and lower (BFS index = 0.7–1.0, low marine influence). Before 2000 BCE, the estuary was moderately open and well-connected to the Atlantic Ocean. From 2000 BCE, the estuary experienced a greater marine influence, increasing in extension, as a consequence of a sea-level rise and subsidence. Immediately afterwards, it began to experience restriction processes due to southward shoreline progradation related to the growth of littoral spits and sediment supply. From 1400 to 1000 BCE, gradual restriction transformed the open estuary into a semiclosed estuary. A last phase of estuary restriction occurred from 1000 BCE to the present day, leading to the lowest salinity and the highest estuary restriction. Finally, the BFS index was successfully applied in two other marginal-marine environments: a Pleistocene lagoon in northern Italy, and a Pliocene coastal bay in southeastern Spain. The index allowed assessment of the degree of restriction in these different environments, supporting its utility in different regions, environments and timescales.
Antonio Rodríguez-Ramírez
added a research item
A multi-proxy palaeoenvironmental study (pollen, non-pollen palynomorphs, charcoal particles, mollusk mac-rofauna) of coastal marshland in Doñana National Park (southwestern Iberian Peninsula) was undertaken to trace environmental change, human activities related to woodland clearance, and past land-use during the mid-late Holocene (~5000-2800 cal BP). The results of this study are combined with archaeological data from the Copper and Bronze Ages and are subsequently compared with those of similar research carried out at the south-westernmost part of Europe with the aim of discerning regional differences or similarities. Our research has allowed us to recognize climate changes and four extreme wave events in the Guadalquivir paleoestuary, which might have contributed to both the cultural change that is observed in the archaeological record at the end of the Chalcolithic and the subsequent population decline during much of the Bronze Age.
Juan J.R. Villarías-Robles
added an update
By Sebastián Celestino-Pérez, Enrique Cerrillo-Cuenca, Ángel León, José Antonio López-Sáez, José N. Pérez-Asensio, Antonio Rodríguez-Ramírez & Juan J. R. Villarías-Robles. In Miguel Ferrer (ed.), Anejos Arbor 11: 50 Aniversario de la Estación Biológica de Doñana, pp. 81-100. Madrid: CSIC.
 
José Noel Pérez-Asensio
added 2 research items
There are reasons other than biological and environmental to argue for the preservation of Doñana National Park—reasons which are geological, archaeological, and anthropological. Up until the establishment of Estación Biológica of CSIC, the lower Guadalquivir River basin was home to a human community adapted to the rich, varied resources of a marshland milieu. Early in the 20th century, the construction of Palacio de la Marismilla led to the unexpected discovery of a yet older settlement: one by Cerro del Trigo, dated to the 2nd to the 6th century AD, which archaeologist G. Bonsor and philologist A. Schulten excavated in the 1920s. Their project confirmed such occupation, and, in the process, revealed an earlier, prehistoric one, along with clear signs of subsidence of the ground during the Holocene. In effect, Doñana National Park is a setting for relatively rapid geomorphological processes of scientific interest, which can be compared with those that climate oscillations and neo-tectonics have generated elsewhere in the planet over the past millennia. Since 2005 the interdisciplinary Hinojos Project has brought the relevance of these scientific accomplishments to bear on its own results—mainly, on the one hand, the evidence of settlement and cultural development that goes back to at least Neolithic times and, on the other, the traces of a rapid geomorphological dynamics that combines long phases of alluvial sedimentation and subsidence of the ground with short, periodic events of high-energy marine transgression. Full text in: http://editorial.csic.es/publicaciones/libros/12647/978-84-00-10101-5/donana-50-anos-de-investigaciones-cientificas.html KEY WORDS: Doñana, Guadalquivir paleo-estuary, Middle Holocene, Late Holocene, Geomorphological evolution, Neo-tectonics, Extreme Wave Events, Subsidence, Settlement changes, Neolithic, Copper Age, Bronze Age, Roman period, Islamic period. RESUMEN: Hay más razones que las biológicas y medioambientales para conservar Doñana: son razones geológicas, arqueológicas y antropológicas. Hasta la constitución de la Estación Biológica del CSIC en 1964, la comarca del bajo Guadalquivir estuvo habitada durante siglos por una comunidad humana adaptada al aprovechamiento de los muchos recursos que el medio marismeño ofrece. A comienzos del siglo XX, la construcción del Palacio de La Marismilla tuvo por efecto inesperado el descubrimiento de los restos de un poblamiento más antiguo aún: el del yacimiento de El Cerro del Trigo, de los siglos II a VI de nuestra era, que el arqueólogo G. Bonsor y el filólogo A. Schulten excavarían en la década de 1920. Su proyecto confirmó este poblamiento y, además, reveló indicios de otro, más remoto todavía, de la prehistoria, así como señales de una subsidencia general del terreno durante el Holoceno. El Espacio Natural es, en efecto, escenario de procesos geomorfológicos de duración relativamente rápida que tienen un gran interés científico; son comparables a los que generan en otras zonas del planeta las fluctuaciones climáticas y la neo-tectónica de los últimos milenios. El pluridisciplinar Proyecto Hinojos, iniciado en 2005, ha puesto en valor estos referentes para la ciencia sobre Doñana a la luz de sus propios resultados: principalmente, de un lado, evidencias de poblamiento y tradiciones culturales que se remontan al menos al Neolítico y, de otro, claros signos de una rápida dinámica geomorfológica de fases sedimentarias aluviales y de subsidencia, interrumpidas periódicamente por episodios erosivos de origen oceánico de alta energía. PALABRAS CLAVE: Doñana, paleo-estuario del Guadalquivir, Holoceno Medio, Holoceno Superior, evolución geomorfológica, neo-tectónica, episodios de transgresión oceánica extrema, subsidencia, cambios en poblamiento, Neolítico, Calcolítico, Edad del Bronce, época romana, época andalusí.