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The Guadalquivir River Basin is one of the largest in the Iberian Peninsula and has a remarkable freshwater biodiversity. Although many studies on hydrological regimes or water quality have been conducted in this basin the biodiversity of freshwater fish, as well as their distribution and conservation status, has never been globally addressed as in other Iberian basins. In this context, we synthesized information on freshwater fish using field procedures and a bibliographic search. Fish distribution patterns at different spatial scales and general environmental conditions were analyzed as well as the conservation status of the fish community. We documented the presence of 40 species (20 native and 20 exotic) in the basin during the 20th century until today. However, we only captured 18 species during the field sampling, with a prevalence for any native species of less than 23% (except Luciobarbus sclateri). The highest species richness was found in mid reaches, while the lower reaches had very low diversity values. Around 50% of species are threatened; according to the IUCN, several species are declining at an alarming rate and others are probably extinct and/or their current status is unknown. Human disturbances during the last few decades have caused serious changes in fish distribution and consequently to their conservation status. Hydrological alterations, intensive agriculture and introduced species are probably the principal reasons for Guadalquivir's ichthyofauna imperilment. Our study indicates an urgent and real need to identify important areas for fish conservation to guarantee a minimum fish biodiversity conservation over the long term, as well as effective strategies for fish recovery where it still is possible. [ABSTRACT FROM AUTHOR]

From the analysis of writings and maps of the era of commercial trade with America, we have detected the existence of two completely unknown structures submerged at the mouth of the Guadalquivir River, the Bastion of San Felipe and the Dock of "La Riza ". By using Photographic Rectification as a survey method, we offer a research methodology which unifies the processes of documental analysis and those related to architectural surveys. As a result of this study, both structures are located and are plotted on maps of the river mouth on which we also show the position of the former navigation channel and a restitution of the map of Sanlúcar de Barrameda in the 18th century. We give several hypotheses about the use and the typology of both elements, as well as their impact on the morphological evolution of the coast. [ABSTRACT FROM AUTHOR]

In this study we assessed the effects of the recurrent disposal of dredged material from the Guadalquivir estuary (south-western Spain) in a marine disposal area. We analysed shifts in sediment characteristics as well as bioaccumulation and biomagnification of heavy metals through the benthic food web. Results showed that the significant increase in concentration of some heavy metals observed in the marine disposal area after the latest disposal event could be attributed to the deposition of river-dredged sediments. This increase could also explain the decreased amphipod survival in the ecotoxicology analysis. Heavy metal concentrations in organisms indicated some bioaccumulation in deposit feeders and predators but with no clear patterns nor biomagnification through the food web. Hence, combining studies that monitor shifts in sediment characteristics and their possible consequences for the food web seems to be an interesting approach that should be assessed further in this type of studies. • Recurrent depositions without enough recovery time lead to permanent changes. • Disposal area had coarser grain size, lower organic matter and metal concentration. • The disposal increased the concentration of metals which remained for one year. • Same bioaccumulation patterns were found in the disposal and control areas. [ABSTRACT FROM AUTHOR]

• Gulf of Cadiz zooplankton spatio-temporal variation described for the first time. • Guadalquivir River makes the difference and determines much of basin zonation. • General decrease in the last five years. This study provides the first comprehensive description of the Gulf of Cadiz (SW Spain) marine zooplankton community. To do this we compiled information from a number of surveys and monitoring programs carried out in the area over the last 14 years. Using this time-series of quarterly (3 times per year) resolution, we describe their general composition, spatio-temporal variability and relationship with environmental factors. Zooplankton is dominated by copepods (mainly Clausocalanus , Paracalanus , Oncaea and Oithona), except in warm periods, when outbreaks of cladocerans (mainly Penilia avirostris but also Podon intermedius and Pleopis polyphemoides) outnumber copepods, accounting for more than 80% of total abundance on occasion. Zooplankton diversity was found to be higher in deeper waters while the density of most taxa (but not their abundance) decreased towards the ocean. On top of this general coast-ocean pattern a north–south gradient could also be distinguished resulting in three distinct zones. In relation to environmental structuring, mesoscale processes, sea surface temperature, winds, river runoff and primary productivity were identified as main factors shaping this zonation. Overall, zooplankton abundance showed a decreasing trend during the study period (2001–2015), caused by a drop of summer abundances, that was mainly driven by cladocerans. [ABSTRACT FROM AUTHOR]

Morales, R.; Borrego, J.; Carro, B.M., and Morales, J.A, 2020. Depositional facies along the banks of Guadalquivir Estuary (SW Spain). In: Malvárez, G. and Navas, F. (eds.), Global Coastal Issues of 2020. Journal of Coastal Research, Special Issue No. 95, pp. 573–577. Coconut Creek (Florida), ISSN 0749-0208. The Guadalquivir Estuary is located at center of the Cadiz Gulf. It is an estuary supplied by one of the longest rivers of Spain. The Guadalquivir estuarine channel extends from the town of Sevilla to its mouth in front of Sanlúcar de Barrameda (Cádiz), bordering Doñana National Park along its southeastern margin. Guadalquivir River has an average discharge of 185 m3/s, with a strong seasonal character. This estuarine zone is characterized by a mesotidal range, with a mean tidal amplitude of two meters. Water usually has a high concentration of suspended matter, being one of the most turbid estuaries in the world. The channel margins mainly develop muddy facies with a clearly visible parallel lamination that has been described and interpreted as a result of the alternation between wet and dry seasons and longer climatic cycles. A zonation of the estuary is suggested as a result of the tidal facies distribution. [ABSTRACT FROM AUTHOR]

Spain has the most reservoirs in Europe, and is near the top of the list globally. Despite this, national hydrological planning still continues to rely overwhelmingly on this type of infrastructure. This indicates that the traditional hydraulic paradigm is deeply entrenched in Spain. The present work takes the new, hitherto unexplored perspective of public resistance, and seeks to complement other studies by aiming to understand why a hydrological transition, in line with environmental demands, has not taken place in Spain. In order to do this, we analyze data from a representative survey (years 2004–2013) of the residents of one of Spain's most densely regulated drainage basins, that of the Guadalquivir River. Our results reveal that during a several drought (2005–2008), people's support for the construction of new reservoirs declined sharply, whilst social resistance to changes in the water management strategy was associated with profiles closest to the agricultural sectorm and characterized by a lack of awareness about water distribution in productive sectors [ABSTRACT FROM AUTHOR]