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The southwest of the Iberian Peninsula is subject to irregular rainfall patterns with recurring opposite events, periods of drought or intense rain. Based on documentary sources, in the context of the particular hydrological conditions of the city and its urban protection system, the corresponding impacts of the Guadalquivir River in Seville during the 18th century are examined. Events that reveal vulnerability to extreme weather events are described. This has allowed us to prepare the annual water risk index. From its quantification, the temporal evolution throughout the 18th century is obtained. Irregularly distributed, variability is observed, in which the effects of drought are more frequent in the first half of the century and floods in the final decades. [ABSTRACT FROM AUTHOR]

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]

A three year-long quasi continuum sampling dataset on the Guadalquivir estuary water quality was used to assess the role of light availability on its biological production. We found that inorganic nutrients within the estuary are very high (with mean values for inorganic nitrogen and phosphorous of 285 and 2.4 μM respectively) while phytoplankton biomass remains low most of the time (with a mean value of 2.6 mg/m 3 ). A strong relationship between phytoplankton biomass and water turbidity was found indicating that, indeed, light availability is the major constraint of primary production in this system. Most of the time this limitation of primary production is not associated to enhanced turbidity connected to fresh water inputs. Instead, our data indicate that, independently of freshwater inputs, the photosynthesis is restricted by tidal forcings enhancing turbidity in an estuary that has been highly modified. Our results match with classical theories on the functioning of well-mixed, estuarine ecosystems as well as with recent modeling exercises. We also discuss the potential impacts of this particular characteristic of some estuarine systems for their management and regulatory control. [ABSTRACT FROM AUTHOR]

Since the middle of the last century the river areas of Andalusia have undergone a process of degradation. This paper presents a historical and multiscale approach of the spatial distribution of river areas by using the land cover maps. At regional level, evidence of that Andalusia has lost a tenth of river areas over the last six decades. Secondly, analyzed of two local paradigmatic cases (Guadalmina river and Guadalquivir river) that can be extended to the rest of territory. The effort for the management of river areas has not been reflected in the results, being the interrelationships between water and land management (regional, sub regional and municipal) still an unresolved issue. [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]

Auf Grund zahlreicher archäologischen und kunsthistorischen Arbeiten zeigt der Aufsatz, wie die Grablöwen in die Italische und Iberische Halbinsel sowie in Galoromania und in Dazien eingeführt wurden. Der Grund dafür war, dass die römischen Eroberer den Wunsch hatten, ihren Toten eine Beerdigung wie in ihrer ursprünglichen Heimat zu gewähren. Wahrscheinlich waren die Grablöwen am Anfang ausschliesslich in den am meisten mit Römern bevölkerten Regionen (der mittlere und untere Mieresch, der untere Guadalquivir, die Rhonemündung usw.) geübt worden. Mit der Zeit und dem fortschreitenden Romanisierungsprozess wurden sie auch von anderen Teilen der Bevölkerung übernommen. So bewies er Verallgemeinerungstendenzen in der römischen Kultur. Alle hier erwähnten Gegende besassen schon vor der Eroberung eine gewisse "Löwenkultur", d.h. Gegenstände mit Löwenbildern, Erzählungen über Löwen etc. Die Grablöwen bereicherten diese Kultur. Die in unseren Zeiten bekannten Monumente sind Zeugen der damaligen Kultur und Beweise dafür, wie die Reichskultur sich zu vereinheitlichen versuchte. In Dazien wurden die Grablöwen auf die Zeit von 105-196 bis 273-275 begrenzt, insgesamt etwa 170 Jahre, d.h. die Zeit in der sich die Provinz unter römischen Berherrschung befand. Lang genug damit sie, zusammen mit anderen alltäglichen Phänomenen des römischen Lebens als Zeitpunkt verstanden werden kann, wo eine der interessantesten Colinden (profane Weihnachtslieder) entstehen konnte. Dies ist aber das Thema einer zukünftigen Studie. [ABSTRACT FROM AUTHOR]

* Premise of the study: The Ibero-North African Carex sect. Phacocystis river-shore group is a set of perennial helophytic species with poorly defined taxonomic boundaries. In the present study, we delimited the different taxonomic units, addressed the phylogeographic history, and evaluated the drivers of differentiation that have promoted diversification of these plants. * Methods: We analyzed molecular data using statistical parsimony for plastid sequences (26 samples from 26 populations) and principal coordinate analysis, neighbor joining, and Bayesian analysis of population structure for AFLPs ( 186 samples from 26 populations). Chromosome numbers from 14 samples (9 populations) are newly reported. * Key results: Three species can be distinguished (C. acuta, C. elata, and C. reuteriana). Unexpectedly for rhizome-growing helophytes, the vegetative reproduction detected was incidental. The widespread C. elata was found to be a genetically poorly differentiated taxon, whereas the local C. reuteriana displayed geographical structuring. Geographical factors seem to be the main driver of differentiation for both taxa. * Conclusions: Despite apparent morphological and ecological similarities, C. elata and C. reuteriana have disparate genetic structures and evolutionary histories, which may have originated from small ecological differences. Carex elata is broadly distributed throughout Europe, and its northern populations were recently founded, probably after the last glacial maximum. In contrast, C. reuteriana is an Ibero-North African endemic, with long-standing populations affected by isolation and limited gene flow. It is likely that high-density blocking effects and different gene-flow barriers act together to delimit its distribution and promote its relatively high population differentiation. [ABSTRACT FROM AUTHOR]

Abstract: Mysid shrimps are an important component of estuarine food webs because they play a key role in energy transfer as intermediate prey. We investigated the seasonal, tidal and depth specific variation in the diet of the estuarine mysids Neomysis integer and Rhopalophthalmus tartessicus and explored its implications for the planktonic community structure of a temperate estuary (Guadalquivir Estuary, SW Spain). Neomysis integer is an opportunistic omnivore feeding mainly on mesozooplankton and on members of the detrital–microbial loop, shifting prey seasonally according to availability. In contrast, R. tartessicus showed a more carnivorous diet and shifted its target prey during seasons of low resource availability. Despite statistically significant differences in diet composition, both species shared prey of similar size, particularly juvenile Mesopodopsis slabberi, the most abundant mysid species in this estuary, and copepods. Although these similarities imply inter-specific resource competition, their co-existence is achieved by niche partitioning and spatial segregation: the higher osmoregulatory capacity and foraging plasticity of N. integer confers a broader niche breadth for this species allowing N. integer to inhabit the more stressful oligohaline region of the estuary where R. tartessicus cannot survive. We propose that this mechanism relaxes the potential for competition between N. integer and R. tartessicus. [Copyright &y& Elsevier]

• 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]

Estuaries are significant methane (CH4) and nitrous oxide (N2O) emitters, although dynamics of both greenhouse gases in these ecosystems are regulated by complex processes. In this work, we aimed at characterizing the spatio-temporal distribution of CH4 and N2O in the Guadalquivir river estuary (SW Spain), the southernmost European estuary. During eight sampling cruises conducted between 2016 and 2017, surface water CH4 and N2O concentrations were measured along the salinity gradient of the estuary by using static-head space equilibration gas chromatography. The CH4 and N2O saturation ranges over the estuarine transect were 520-30,800% (average 2285%) and 40-390% (average 183%), respectively and air-water fluxes ranged from 13 to 1000 µmol m− 2 day− 1(average 66.2 µmol m− 2 day− 1) for CH4 and from − 7 to 35 µmol m− 2 day− 1 (average 8.5 µmol m− 2 day− 1) for N2O. A slight increase in the emissions was detected upstream and no seasonal trends were observed. Mixing between freshwater and oceanic waters influenced biogeochemistry of estuarine waters, affecting CH4 and N2O fluxes. In order to identify potential sources of CH4 and N2O, biogeochemical parameters involved in the formation pathways of both gases, such as salinity, dissolved oxygen, nutrients and organic matter were analyzed. Results suggested that sulfate inhibition and microbial oxidation played a relevant role in dissolved CH4 accumulation in the water column whereas associations found between N2O, nitrate and oxygen indicated that nitrification was a major source of this gas. Therefore, the influence of the tidal-fluvial interaction on ecosystem metabolism regulates trace gas dynamics in the Guadalquivir estuary. [ABSTRACT FROM AUTHOR]