SW Spain Research Articles

Insights from a comparative GIS-MCDA groundwater vulnerability assessment in a granitic and metasedimentary fractured rock media

This work proposes a comprehensive methodology for evaluating fissured hard-rock groundwater resources through an integrative approach based on fieldwork techniques, Geographic Information System (GIS)-based mapping, geospatial analysis and multiple-criteria decision analysis (MCDA). The study sites comprise distinct geological settings and geographic contexts, i.e. granitic rocks (NW Portugal) and metasedimentary rocks (SW Spain). A similar methodological approach was used in both areas to compare and assess the methodological approaches’ effectiveness. The cartographic, field, and laboratory data were analysed through GIS overlay and multi-criteria spatial analysis. This GIS-integrated analysis allowed the calculation of the Infiltration Potential Index (IPI) and groundwater vulnerability indexes: GOD-S, DRASTIC-Fm, SI and DISCO, as well as the development and improvement of the hydrogeological conceptual models. At the Entre-os-Rios site (NW Portugal), the IPI index showed that the most favourable areas for infiltration are the fractured granitic regions, where the slope has the lowest values, combined with forest areas. The recharge values are around 70 to 90 mm/year. Considering hydraulic connection with the borehole data, the DISCO index identified the geostructures with the most important trending to NNE-SSW, NE-SW and WNW-ESE in the area. The highest IPI values were identified in the regional aquifer quartzite unit at Herrera del Duque (SW Spain). The recharge values are around 60 to 80 mm/year. The DISCO index identified zones where discontinuities have a higher hydraulic connection to the borehole, mainly trending NW-SE and NE-SW. The models developed could be helpful for decision-making and sustainable water resources management regarding the planning of hydrogeological investigations, delineating potential contamination areas, and the definition of catchment protection areas.

EstuarIndex: an eco-geomorphological index to assess the conservation state of estuaries

The main objective of this work is to present a novel methodology to assess the environmental, ecological, and conservation status of mid-latitude estuaries by means of an index-based method, EstuarIndex. The EstuarIndex is an integration of four sub-indexes, assessing the status of the main subsystems present on estuaries: sandy environments, dunes, tidal flats, and the drainage network. Each sub-index includes variables combining three types of factors: morphosedimentary and oceanographic factors, ecological factors, and management and protection factors. The environmental status is finally evaluated in five possible classes: (1) Very low, (2) Low, (3) Medium, (4) High, and (5) Very High, according to EU requirements for classifying the conservation status of habitats. Three pilot zones along the Spanish coast have been chosen for testing the method: San Vicente de la Barquera estuary (N Spain), Guadiana estuary (SW Spain), and Ebro River delta mouth (E Spain). They present different oceanographic and geomorphological conditions. The results obtained have proven that EstuarIndex is a suitable methodology for the application to other estuaries. The systematic application of EstuarIndex on broad time scales would allow evaluating the system trends, what seems key for implementation of more realistic restoration strategies, and it has a great potential as a tool for environmental management in natural protected areas. Furthermore, it may help in the detection of the most relevant site-specific vulnerabilities for long-term sustainability in response to both natural and artificial drivers.

Unveiling High-Tech Metals in Roasted Pyrite Wastes from the Iberian Pyrite Belt, SW Spain

The Iberian Pyrite Belt (IPB), in the southwestern Iberian Peninsula, is a large metallogenic province exploited since ancient times. As a result of historical and current mining activity, a vast volume of metallic mineral waste, mainly derived from the processing of pyrite, is still in situ and polluting the environment. A specific mine waste residuum locally known in the area as “morrongos”, which was produced during pyrite roasting mainly in the 19th century, is evaluated here in order to unravel untapped resources of high-tech metals commonly used in high-tech devices. Applying a combination of whole-rock geochemical (ICP-AES, ICPMS, FA-AAS) and single-grain mineralogical techniques (EPMA, LA-ICP-MS, FESEM, and FIB-HRTEM) on the “morrongos”, we unhide the still-present remarkable concentrations of Au, Ag, Pb, Zn, and Cu in them. The mineralogical expressions for these economic metals include oxides (hematite, magnetite, and hercynite), arsenates, sulfates of the jarosite group, native metals, and, to a lesser extent, relictic sulfides. This first-ever estimation of these economic metals in this type of residue allows their revalorization, highlighting them as suitable sources for the exploitation and recovery of metals necessary for the clean energy transition.

Analysis of Aquifer‐System Deformation in the Doñana Natural Space (Spain) Using Unsupervised Cloud‐Computed InSAR Data and Wavelet Analysis

AbstractThis work is focused on the Almonte‐Marismas aquifer located within Doñana Natural Space (SW Spain); this aquifer is threatened by droughts, irrigation‐driven groundwater overexploitation, urban use, and the potential reactivation of gas extraction and storage projects. We present ground deformation measurements from Sentinel‐1 Interferometric Synthetic Aperture Radar (InSAR) data ranging from 1 to 2.5 cm, covering ∼2,500 km2 from 2014 to 2020. Detecting spatially distributed ground deformation over this agricultural area is challenging due to the low‐coherence radar signals; consequently, the ground movement results are on the same order of magnitude as the errors associated with InSAR data. We have approached this issue by considering auxiliary information such as groundwater levels, climatic time series, and pumping rates and analyzing their spatio‐temporal connections to ground displacements. We correlate InSAR and hydrogeological information through wavelet analysis, developing a Python package that allows applying the same methodology in other similar study areas. For the first time in the Doñana area, a significant relationship between distances to pumping wells and the displacement extent is detected. Moreover, other subsidence‐related triggering factors are identified, such as the soil moisture balance, clay shrinking‐swelling processes, and creep of geological formations. These results are highly valuable to support aquifer management decisions in the Doñana Natural Space; in this border region, three groundwater bodies were officially declared overexploited in 2020. Our findings provide a ground motion baseline assessment to help differentiate historical variations from any future anthropogenic effect in this complex marsh land ecosystem.

Hominid Alluvial Corridor (HAC) of the Guadalquivir and Guadaíra River Valleys (Southern Spain): Geoarchaeological Functionality of the Middle Paleolithic Assemblages during the Upper Pleistocene

This research addresses the geomorphological connectivity existing amid the piedmont’s karstic fillings (Sierra de Esparteros) and the Guadaíra and Guadalquivir Rivers’ alluvial terraces (SW of Spain), spotted with vestiges of human activities (Middle Palaeolithic). This study includes the analysis of 20 geoarchaeological sites and 28 lithic assemblages, with a total of 13,233 lithic pieces. Techno-typological and use–wear (SEM) analyses were conducted on these artifacts. Depending on the raw materials and the provenance of these lithic industries, two groups of assemblages were identified: one made of quartzite from the north, and another made of flint from the south. Two main geochronological periods were established (OSL and U/Th): (1) a short duration (MIS6/MIS5) and (2) a long duration (MIS5/MIS3). Techno-typological analysis showed three sorts of activities: (a) the provision and distribution of raw materials, (b) knapping, and (c) other activities that imply the use of a lithic workshop (LW), along with the settlement characteristics of habitual or recurrent (HS), temporary (TS), and indeterminate (IN). This geoarchaeological connectivity is called the “hominid alluvial corridor” (HAC). The underlined features are the geomorphological units, the continuum alluvial series, the raw material of the lithic industries as an indicator of provenance and transportation throughout the alluvial system, and the use–wear analysis of the tool-kit to interpret the functionality of the pieces.

Quantification and identification of damage caused by pests and fungi in dried figs from orchards with different levels of agronomic management in the main production areas of extremadura (SW Spain)

This work aimed to evaluate the effect of agronomic management and water regime on the number of lesions, levels of insect infestation and microbiological quality of dried figs in Extremadura. Dried fig samples from 18 orchards were collected. The results showed that birds were the primary pests, causing damage to dried figs, followed by insects and fungi. The effects of orchard management were more pronounced under irrigated conditions, with the percentage of undamaged dried figs and the number of insect-free fruits rising significantly with increasing management. Under rainfed conditions, the level of orchard management did not significantly influence damage. In addition, insects were detected in both damaged and undamaged dry figs. Cadra figulilella, Carpophilus hemipterus and Ceratitis capitata were the most common species. Regarding mycobiota, orchard conditions did not significantly affect fungi counts, but they did influence species composition. Aspergillus spp. were predominant under all conditions, followed by Alternaria spp. under irrigated conditions. This work provides relevant information on the different biotic agents that affect dried figs, showing that a higher level of management under irrigated conditions reduces pest incidence. Such knowledge is essential for designing control methods to obtain higher quality fruits.

Different evolution of tensile and compressive strength in concrete affected by acid mine drainage

Although not many studies have analysed the effects of acid mine drainage (AMD) on the durability of concrete, it is clear that such an aggressive environment affects the different mechanical parameters of this material. AMD is an environmental problem that affects the five continents and is especially widespread in the south western part of the Iberian Peninsula, in an area known as the Iberian Pyrite Belt.In this work, the effect of AMD on tensile and compressive strength of concrete has been evaluated, analysing the evolution of these two fundamental parameters on this structural material. For this purpose, a series of concrete samples were subjected to a controlled AMD environment in the laboratory, using water with pH 2.8 collected from the Tharsis Mine (SW Spain). The concrete samples were prepared in accordance with the parameters required by various international standards.The samples were subjected to the aggressive environment by AMD for two periods of time (3 and 6 months), after which they were subjected to non-destructive testing and destructive testing until breaking the samples by means of compression and tensile (indirect tensile test). In addition, Emission Scanning Electron Microscopy studies were performed on samples before AMD influence and on samples affected by AMD for six months.The obtained results using the ultrasonic equipment showed a decrease in concrete quality, an increase in porosity and permeability, the reduction of modulus of elasticity that reaches 8.5% after six months, as well as the appearance of microcracks. The destructive the tests showed that tensile strength is much more affected than the compressive strength: the tensile strength went from 4.31 MPa to 3.27 MPa (24%) after six months, while the compressive strength went from 48.22 MPa to 43.83 MPa (9%) in the same period of time. This different evolution means that the formulas used in international standards that relating compressive strength to tensile strength need to be modified by means of a correction factor.

Neanderthal footprints in the “Matalascañas trampled surface” (SW Spain): new OSL dating and Mousterian lithic industry

In the Huelva Coast of SW Spain erosion by recent marine storms revealed the presence of a paleosol where an extensive tracksite known as “Matalascañas Trampled Surface” (MTS) has been documented. The MTS includes tracks and trackways of large species of mammals, along with bird trace fossils, invertebrate burrows and root traces. Within this record, the presence of several hominin footprints and trackways stands out. Despite previous uncertainties about the producer of these footprints, new OSL age of 151 ± 11 ka secures their attribution to Neanderthals, the only hominins known to have been present in the Iberian Peninsula during the MIS6-5 transition. Moreover, typical Mousterian lithic industry with Levallois knapping was found associated with the ichnological record. This lithic industry is characterized by the selection of raw materials from outcrops in a short-distance range to the tracksite. The general characteristics of the lithics are derived both from the nature of the raw material and from the nature of the site itself, which cannot be seen as a settlement, but rather as a place of passage for fauna, including Neanderthals, where a few human individuals performed short-term activities, such as food procurement and/or meat processing.

A post-collisional batholith from Southern Iberia rooted in the Earth's mantle: Los Pedroches batholith

The Los Pedroches batholith (SW Spain) is one of the most salient igneous alignments of the Iberian massif. The batholith is considered one of the best examples of post-collisional batholiths of Iberia and is dominated by a biotite granodiorite that was emplaced in the shallow crust postdating the main deformation phases of the Variscan orogeny. In the Quintana de la Serena area, to the northwest of the batholith, granodiorites were partially emplaced into dacites characterized by the presence of abundant orthopyroxene. The quality of outcrops and abundant quarries in the area, together whit the near absence of local crustal contamination, make this zone an ideal location for petrogenetic studies about the origin of granodiorite magmas and their related microgranular enclaves. We present in this paper new SRHRIMPII-based zircon geochronology data that indicate orthopyroxene-bearing subvolcanic rocks emplaced and cooled at the age of 310 ± 2 Ma, slightly earlier than the intrusion and cooling of the massive granodiorites (307 ± 1 Ma and 306.6 ± 0.7 Ma) and their related mafic microgranular enclaves (307.8 ± 0.8 Ma). Whole rock geochemistry demonstrates that the three groups of rocks, dacites, granodiorites and mafic microgranular enclaves, define a coherent geochemical trend indicating that they are cogenetic and related by fractionation of a common parental magma. This study proves the role played by intermediate magmas of sanukitoid affinity in the generation of the most abundant and massive granodiorite rocks that form large post-collisional batholiths in Iberia.

Spatial distribution patterns of striped venus clam (Chamelea gallina, L. 1758) natural beds in the Gulf of Cádiz (SW Spain): Influence of environmental variables and management considerations

Spatial distribution of characteristic population parameters (density, biomass and mean size) of Chamelea gallina were analyzed from systematic survey data applying a geostatistical approach in the Gulf of Cádiz (SW Spain). The influence of static (depth and distance to inland outflows), dynamic (sediment and water column features) environmental variables on density, biomass and mean size was also investigated. The global estimations of kriged density mean was 8.30 ind m−2, biomass mean was 23.78 g m−2, and mean size was 18.71 mm, with the species heterogeneously distributed along the whole sandy subtidal strip of the coast of Huelva. The resulting kriged map shows the location and extension of the patches (5 NM range) in the study area; where the highest density and biomass hot-spots were observed near the river mouths, except for the Guadiana River. This species was present from 3 to 16 m, but preferred the depth window between 6-8 m, having a density and biomass peak at approximately 7 m depth. A negative and significant correlation was found between density/biomass and the coefficient of variation of mean size suggesting a density-dependent process. The most influential factors on density and biomass were depth, sediment characteristics (grain size and percentage of organic content), distance from river mouths and waste water treatment plants, and sea bottom temperature. This study, in addition to reporting on the current status of these natural beds and the influence of dynamic and static environmental variables on their distribution, proposes an additional approach to estimating several biological parameters in C. gallina that could be valuable for the spatial management of this commercial resource and highlight the role of marine protected areas.

First report of Eimeria myoxi in the garden dormouse (Eliomys quercinus Linnaeus, 1766) from Doñana Natural Area (Andalusia, SW Spain).

This work reports for the first time the presence and molecular characterization of Eimeria myoxi in the garden dormouse (Eliomys quercinus) from the Doñana Natural Area (Andalusia, SW Spain). Fresh faecal samples were collected from a total of 28 garden dormice, which were caught following current guidelines for the ethical use of animals in research, and processing by a standard flotation technique with saturated saline solution. Then, wet drops were examined microscopically, and the number of oocysts was semi-quantified. Eimeria oocysts were observed in 16 of the 28 (57.1%) faecal samples, showing most of them a very low number of oocysts (≤1 oocyst per microscopic field × 400). The unsporulated oocysts visualized in 16 faecal samples were subspherical and of length 19.2±1.2μm and width 17.4±1.1μm, being morphologically compatible with E. myoxi. This finding was supported by molecular analysis of the small subunit ribosomal RNA (SSU-rRNA) gene, identifying the same species in 22 of the 28 (78.6%) dormice, including 15 samples in which oocyst size was compatible with E. myoxi. Moreover, the subsequent analyses of the apicoplast open reading frame 470 (ORF470) and the mitochondrial cytochrome c oxidase subunit I (COI) genes confirmed the molecular identification of the isolates as E. myoxi. The phylogeny analyses were consistent with previous phylogenetic studies and support the existence of three lineages of rodent-infecting Eimeria species.

Indirect interactions between pollinators drive interaction rewiring through space

AbstractIn recent years, an extended body of literature has focused on the importance of either temporal or spatial dynamics in shaping the structure of interacting plant and pollinator communities. This improvement from a previously static and aggregated perspective has allowed us to understand many of the ecological processes that shape community assembly. However, fewer are the studies that have simultaneously focused on spatial and temporal dynamics, and even fewer are those that collect data across different habitat types to assess the generality of their findings. Here, we used a dataset collected weekly throughout the full flowering season for two consecutive years and within two contrasting habitat types in N and SW Spain: a mountain grassland area and the understory of sparse pine forests. We evaluated species and interaction persistence through space and time, pollinator fidelity, and turnover patterns in interaction composition while providing a potential mechanistic explanation for the patterns observed. Our results show that although species generalization does not explain species or interaction persistence, moderately generalist species are those showing the greatest fidelity to the subset of plant species they visit through space and time. Further, we find that interaction turnover through time is mostly driven by changes in species composition, while through space it is mostly driven by interaction rewiring resulting from indirect competitive interactions between pollinator species. Our results help to shed light on the potential mechanisms driving community assembly patterns beyond niche or neutral processes by adding within‐trophic‐level interactions that can modify pollinator preferences.

High Species Richness of Decapod Crustaceans on an Urban Rocky Shore Beach

The rocky intertidal shore of La Caleta, an urban beach located in Cádiz (SW Spain), was surveyed for decapod crustaceans over a year. Samplings were taken monthly (March 2015 to February 2016) in three differentiated zones during the spring low tides of every month at five sites, differentiated according to the hydrodynamic regimes and intertidal levels. A qualitative sampling (present/absent) was carried out by visual identification (minimally invasive), and only those specimens with uncertain identification were collected by hand, studied at the laboratory, or identified using their DNA barcode. A total of 44 species were identified. Comparison with species richness of decapod crustaceans in other Atlantic and Mediterranean intertidal or subtidal ecosystems (including protected areas) shows higher values in La Caleta, a surprising fact considering the type of habitat and its placement (an urban and unprotected shore).

Video-Monitoring Tools for Assessing Beach Morphodynamics in Tidal Beaches

Beach behaviour and evolution are controlled by a large number of factors, being susceptible to human-derived pressures and the impacts of climate change. In order to understand beach behaviour at different scales, systematic monitoring programs that assess shoreline and volumetric changes are required. Video-monitoring systems are widely used in this regard, as they are cost-effective and acquire data automatically and continuously, even in bad weather conditions. This work presents a methodology to use the basic products of low-cost IP video cameras to identify both the cross-shore and long-shore variability of tidal beaches. Shorelines were automatically obtained, digital elevation models (DEMs) were generated and validated with real data, and the outputs were combined to analyse beach behaviour from a morphodynamic perspective. The proposed methodology was applied to La Victoria Beach (SW Spain) for the analysis of beach variations over a 5-year period. The combination of shoreline position analysis and data from DEMs facilitates understanding and provides a complete overview of beach behaviour, revealing alongshore differences in an apparently homogeneous beach. Furthermore, the methods used allowed us to inter-relate the different processes occurring on the beach, which is difficult to achieve with other types of techniques.

DISTRIBUCION DE LOS FORAMINIFEROS PLANCTONICOS DEL PLIOCENO EN LA PLATAFORMA CONTINENTAL DEL SW DE ESPANA

Planktonic Foraminifera assemblages from cores of a borehole are studied. Depth interval is from 380 m to 2300 m. The drill site is located in the continental shelf of "Golfo de Cadiz" (SW Spain). The distribution of planktonic foraminiferal species is in agreement with Blow's zonation (1969) extending in age from the Messinian to the Pleistocene.

High resolution mass spectrometry (HRMS) determination of drugs in wastewater and wastewater based epidemiology in Cadiz Bay (Spain)

Multi-residue methods for the determination of the myriad of compounds of emerging concern (CECs) entering in the environment are key elements for further assessment on their distribution and fate. Here, we have developed an analytical protocol for the simultaneous analysis of 195 prescription, over-the-counter, and illicit drugs by using a combination of solid phase extraction (SPE) and determination by liquid chromatography coupled to high resolution mass spectrometry (LC-HRMS). The method was applied to the analysis of influent sewage samples from 3 wastewater treatment plants (WWTPs) from Cadiz Bay (SW Spain), enabling the quantification of more than 100 pharmaceuticals, 19 of them at average concentrations higher than 1 μg L−1, including caffeine (92 μg L−1), paracetamol (72 μg L−1), and ibuprofen (56 μg L−1), as well as several illicit drugs (e.g., cocaine). Wastewater based epidemiology (WBE) was applied for 27 of the detected compounds to establish their consumption in the sampling area, which has been never attempted before. Caffeine, naproxen, and salicylic acid stood out because of their high consumption (638, 51, and 20 g d−1·1000pop−1, respectively). Regarding illicit drugs, cocaine showed the highest frequency of detection and we estimated an average consumption of 3683 mg d−1·1000pop−1 in Cadiz Bay. The combination of new HRMS methods, capable of discriminating thousands of chemicals, and WBE will allow for a more comprehensive characterization of chemical substances and their consumption in urban environments in the near future.

Risk Assessment of a Coastal Ecosystem from SW Spain Exposed to CO2 Enrichment Conditions

The Weight-of-Evidence (WOE) approach uses multiple lines of evidence to analyze the adverse effects associated with CO2 enrichment in two stations from the Gulf of Cádiz (Spain) with different contamination degrees. Sediment contamination and metal (loid) mobility, toxicity, ecological integrity, and bioaccumulation from the samples exposed to different acidification scenarios (pH gradient from 8.0 to 6.0) were used in the WOE. The experiments were conducted under laboratory conditions using a CO2-bubbling system. Different integration approaches such as multivariate analyses were used to evaluate the results. The results indicated that the adverse biological effects under pH 6.5 were related to the mobility of dissolved elements (As, Fe, Cu, Ni, and Zn). Furthermore, the pH reduction was correlated to the increase of bioaccumulation of As, Cr, Cu, Fe, and Ni in the tissues of mussels at pH 7.0. The noncontaminated sediment showed environmental degradation related to the acidification at pH values of 7.0; whereas the sediment moderately contaminated showed both environmental risks, caused by acidification and the presence and the increase of the bioavailability of contaminants. The WOE approach supposes an effective tool to identify and distinguish the causes of adverse effects related to the enrichment of CO2 in marine environments.

Reconstructing the historical shoreline evolution of the Northern Bay of Cádiz (SW Spain) from geomorphological and geoarchaeological data

ABSTRACT During the last 3 ka, different human communities occupied the Bay of Cádiz (SW Spain), including Phoenician, Carthaginian, Roman, Medieval and Modern settlements. Traces of such historical occupations have been recognized along the bay from a geoarchaeological point of view. Some of them bear a palaeogeographical interest related to the historical location of the shoreline. At the same time, Holocene sedimentary units and geomorphological elements identified along the bay can be interpreted as evidences of its morphological evolution. The objective of the present paper is to represent all the available data about archaeological sites and geomorphology in the northern Bay of Cádiz, with the aim of combining both sources of data for elaborating a simple proposal of landscape evolution during the last 3 millennia. The base for mapping was multiple, from historical aerial photographs to satellite imagery and a digital terrain model with a maximum resolution of 0.35 m. .

A Methodology to Design a Wind Transfer Function: Application to the Valdevaqueros Dune (SW Spain)

In general, weather forecasting has been significantly developed at a large scale and, joined with statistical techniques, is used to predict at a local scale. However, there is no way to propagate winds between two nearby locations; this is a spatial transference, for example, for the waves. After studying coastal dunar systems affected by winds, we have proposed a way for the spatial propagation of wind for scales under 10 km. The proposed transference is based on local data, and it is developed in an easy and accurate way by different regression methods and the wind profile theory. The aim of this article is to establish a methodology for achieving a wind transfer function for local applications. For this purpose, we analyzed and compared data from a field experiment and from a nearby weather station. A combination of the wind profile and statistical downscaling technique formed the basis of this research, which leads to transfer equations for wind speeds and directions. To clarify the procedure, the proposed methodology was applied to the Valdevaqueros Coastal Dune in order to develop a transfer function using time series data from a nearby meteorological station located in Tarifa.

Characterization of the water bodies of Extremadura (SW Spain)

Extremadura is the region that stores the greatest amount of fresh water in Spain. Such water is mainly used for power generation, irrigation in agriculture, biodiversity conservation, tourism, recreation, and human and livestock consumption. Nevertheless, crucial information on the total number of water bodies and their geometrical characteristics and spatial distribution patterns are still missing. Thus, our main goal was to characterize the Extremenian water bodies geometrically and spatially through different statistical techniques such as kernel density, Moran’s index, the Getis-Ord Gi*, and principal component analysis (PCA). Firstly, all existing hydrological information was gathered, and using aerial aircraft imagery and satellite images, each water body (WB) was then carefully collected, checked, and corrected. We have inventoried 100,614 WBs (mean density: 2.45 WB km2), irregularly distributed on the territory. WBs with an area < 0.01 km2 (100 ha) represent 64.5% of the total. A multivariate statistical study was conducted, showing that livestock, aridity of the climate, and topography are the main factors controlling the density of water bodies (WBs) in this area. It can be concluded that monitoring of small bodies is crucial to understand their spatial distribution, since they are spread over areas in which extensive farming and commercial crops such as tobacco strongly influence the way of living of many families.