SE Spain Research Articles (Page 1)

Mixing zones in carbonate coastal aquifers are dynamic interfaces where freshwater and seawater converge, triggering complex biogeochemical processes. This study investigates diagenetic barite (BaSO4) precipitation within such a mixing zone in the dolomitic aquifer of the Sierra de Gádor (SE Spain). Three sectors were analyzed: two active mixing zones—one associated with submarine discharge and the other affected by marine intrusion—and an uplifted, fossilized Pleistocene mixing zone. Mineralogical, petrographic, and geochemical analyses reveal extensive dissolution of the dolomitic bedrock, forming polygonal voids and fracture-controlled porosity, frequently covered by Fe and Mn oxides. Barite crystals were identified exclusively in the Fe oxide precipitates at depths where 80% of seawater is reached. The saturation index for barite in groundwater suggests near-equilibrium conditions across the fresh–brackish–saline transition; however, barite precipitation is localized where Fe oxides act as a geochemical barrier, concentrating Ba and enabling nucleation. SEM imaging shows well-formed euhedral barite crystals up to 100 µm in size. This form of crystallization would be similar to the marine diagenetic barite formation models involving organic matter degradation and Ba remobilization, translated to a coastal aquifer setting in this study. Trace metal analyses show significant enrichment of Pb (up to 20 wt%) and other elements (Zn, Ni, and Co), suggesting potential for ore-forming processes if redox conditions shift. This work proposes a conceptual model for diagenetic barite formation in coastal aquifers, emphasizing the role of Fe and Mn oxides as reactive substrates in metal cycling at the land–sea interface.

Green manure from cover crops enhances pesticide degradation and soil biological health.

Summary The Iberian endemic genus Tinautius Mateu, 1997 (Carabidae: Pterostichinae: Pterostichini) is distributed in subterranean habitats of the Betic Systems (SE Spain). It is represented by two hypogean species with different grades of troglobiomorphism: Tinautius troglophilus Mateu, 1997 and T. exilis Mateu, 2001. New records are provided for the two species; in the case of T. exilis, it is for first time recorded from the mesovoid shallow substratum (MSS) of the Sierra de Gádor. Morphological and morphometric differences between species were thorough assessed and compared in collection material from type and new localities (caves and MSS). The results support the segregation of both species in different genera. The genus Gadorites n. gen. is proposed, in which Gadorites exilis (Mateu, 2001) n. comb. is placed. Characters of taxonomical relevance are described and illustrated in detail. Similarities and differences to Caucasian subterranean Pterostichini are discussed. Implications of the presence of G. exilis n. comb. in the MSS are exposed.

Host genetic variability is relevant to understanding how parasites modulate natural selection in wild fish populations. Coastal lagoons are transitional ecosystems where knowledge lacks on relationships between genotypic diversity with parasitism. The aim of this study was to assess the effect of genetic diversity on host health and parasitological traits in fish inhabiting a Mediterranean lagoon. Black-striped pipefish Syngnathus abaster were collected in August 2023 and 2024 from the Mar Menor (Iberian lagoon, SE Spain). Genetic diversity was measured as Internal Relatedness (IR: a homozygosity index from microsatellite markers). Population frequency was lower for the medium IR level. For this same category, both health indices (external body condition and internal organs) indicated a worse status. Parasite prevalence, abundance and an index of life-cycle complexity (heteroxenous species) were greater for the medium level of genetic diversity. Such results are explained under a scenario of parasite-mediated disruptive selection: a higher disease pressure against the phenotypically intermediate individuals. Two contrasting strategies were detected to better control parasitism at the host genotypic level: (1) high homozygosity, and (2) high heterozygosity, which probably reflects better immuno-competence as a phenotypic trait. From an evolutionary perspective, parasites play a crucial role in shaping genetic diversity within host populations.

Facing challenges of urban landslide mapping by complementing geomorphological surveys and satellite interferometry in Alcoy (SE Spain)

Aim of study: Address farmers’ preferences for the adoption of agricultural best management practices in a climate change context and estimate their willingness to accept values for these practices. Area of study: Region of Murcia (SE Spain). Material and methods: The method employed is a discrete choice experiment, whose attributes are the agricultural best management practices for climate change adaptation [regulated deficit irrigation, crop diversification, organic fertilisation, crop residues management, narrowing farmland by 5%, perimeter hedgerows, biological control, enabling eco-tourism activities] and a subsidy to incentivise their adoption. Data were collected for a sample of 250 farmers and analysed by a mixed logit model. Main results: Narrowing farmland by 5%, biological control and the establishment of perimeter hedgerows were the practices generating the greatest values of disutility, and therefore they displayed higher willingness to accept values, ranging from 320 to 410 €/ha/year. In contrast, organic fertilisation and crop residues management were the practices with lowest levels of disutility, and so demanding lower compensatory payments to engage farmers to adopt, which rounded 110 €/ha/year, respectively. Preference heterogeneity was also assessed, revealing that the likelihood of adopting best management practices was determined by farm characteristics (farm size, crop type and farming system) and farmer factors (educational level). Research highlights: Farmers are willing to adopt agricultural best management practices for climate change adaptation if they are associated to properly designed incentives.

Characterisation of mountain-Mediterranean karst aquifers as lighthouses for the assessment of global change impacts in the Mediterranean region: the Sierra Seca aquifer system (SE Spain).

Over the past decades, intensive agriculture has expanded worldwide in response to the rising human demand for food. Intensive farming practices commonly involve the application of pesticides and other agrochemical compounds, contributing to the global decline in farmland bird populations, particularly aerial insectivores. Moreover, the increased mechanization of agricultural operations (e.g., grass cutting, tree pruning, and brush chipping) may destroy nests and reduce the breeding success of ground-nesting bird species. Here, we used a ground-nesting insectivorous bird, the Red-necked Nightjar (Caprimulgus ruficollis), as a model to test for the effects of organic vs. intensive farming practices on breeding performance. We used data from 191 nightjar nests monitored over a 4-year period in a highly cultivated landscape of SE Spain. Four breeding parameters (clutch size, hatching success, fledging success, and overall breeding success) were compared between two adjacent farms under organic and conventional intensive management. Additionally, we compared four population-level attributes (breeding phenology, breeding density, age structure of breeders, and foraging range size) considered to be important determinants of breeding performance. Nightjars breeding in the organic and in the intensive farms had a moderate breeding performance comparable to that reported in other, more extensive agricultural landscapes (e.g., vineyards). All breeding parameters and two out of the four measured population-level attributes were statistically not different between the organic and the intensive farm. However, nest aggregation was higher in the organic farm, and space use analyses revealed that GPS-tracked nightjars nesting within the intensive farm traveled to foraging areas outside the farm more often than those from the organic farm. This suggests that plasticity in foraging behavior (e.g., the use of alternative foraging sites) may buffer the potential negative effects of intensive farming practices (e.g., decreased prey availability) on the breeding performance of nightjars. Our study underlines the potential role of landscape complementation and ecological plasticity in space-use behaviors as determinants of breeding performance in farmland birds, enabling these species to (partly) compensate for the impacts of intensive agriculture.

The Onil and Ibi sections (Prebetic Zone, Betic Cordillera: Alicante, SE Spain) record a late Ypresian (Cuisian) to early Lutetian (~51 to ~43 Myr) carbonate platform succession, dated using larger benthic foraminifera (LBF) and planktonic foraminifera. Seven field lithofacies (L1 to L7) and five thin-section microfacies (Mf1–Mf5) were identified, indicating inner- to mid-ramp environments (from seagrass meadows to Maërl-LBF-dominated) in warm-water and low-latitude conditions. A distinctive feature of these platforms is their dominance by LBF in association with rhodophyceae, contrasting with typical coral reef factories. We propose a novel carbonate production model, “TC-factory”, to describe these warm-temperate systems. Integrated field logging, drone imagery, and microfacies data allowed us to define a sequence stratigraphic framework comprising five lower-frequency sequences (LFS: ~2 Myr average duration), each of them nesting various numbers of high-frequency sequences (HFS: ~0.25 to ~1 Myr). The LFSs belong to a higher-rank sequence bounded by regional unconformities. The five LFSs only broadly match the upper Ypresian and lower Lutetian cycles in global eustatic curves (~51 to ~43 Myr), indicating that other regional or local controls were important. The number of HFSs being fewer than expected also suggests additional controls, such as local tectonics, erosion during lowstands, or carbonate production feedback.

This study analyzes 1980–2020 landings data from three Mediterranean coastal lagoons—the Logarou and Rodia-Tsoukalio Lagoons (NW Greece) and the Mar Menor Lagoon (SE Spain)—to assess ecosystem changes and fishing pressure dynamics. The findings classify these systems as low-yielding, with productivity ranked as follows: Yield Logarou > Yield Rodia-Tsoukalio = Yield Mar Menor. Mean trophic level analysis (mTrL) revealed significant differences driven by the contribution of detritivorous and mid-level carnivorous species (TrL Mar Menor > TrL Rodia-Tsoukalio > TrL Logarou). The fishing pressure indices suggest reduced fishing intensity in the Greek lagoons, while in Mar Menor, a stable Fisheries in Balance (FiB) trend corresponded with stable yields despite eutrophication. Cluster analysis (CA) and principal component analysis (PCA) linked ecosystem differences to sediment characteristics and changes in habitat structure. These results underscore a transition of Mediterranean coastal lagoons toward new ecological states, highlighting the urgent need for habitat conservation and adaptive management strategies to ensure sustainable fisheries under increasing environmental pressures. These findings may be extrapolated to similar transitional coastal ecosystems facing comparable anthropogenic stressors worldwide, providing a broader framework for understanding and managing lagoon systems under changing environmental conditions.

Persistent metal and metalloid fluxes to the seafloor from an underlying mine tailings deposit 25years after disposal off Portmán Bay (SE Spain).

Characterization and potential causes of a whiting event in the Mar Menor coastal lagoon (Mediterranean, SE Spain).

The bivalve mollusk Pinna nobilis is critically endangered. The specimens from the Mar Menor coastal lagoon constitute one of only two surviving populations in Spain. Due to the eutrophic conditions and environmental collapse of the lagoon, the number of living individuals has been drastically reduced. Furthermore, these conditions, along with other factors, have made it difficult for the species to reproduce successfully. In this report, a new recruitment of individuals detected in the Mar Menor is described for the first time in years. It was considered their spatial and size distribution, and their estimated age.

Floods are a major threat to human life and economic assets. Monitoring these events is therefore essential to quantify and minimize such losses. Remote sensing has been used to extract flooded areas, with SAR imagery being particularly useful as it is independent of weather conditions. This approach is more difficult when detecting flooded areas in semi-arid environments, without a reference permanent water body, than when monitoring the water level rise of permanent rivers or lakes. In this study, Random Forest is used to estimate flooded cells after 19 events in Campo de Cartagena, an agricultural area in SE Spain. Sentinel-1 SAR metrics are used as predictors and irrigation ponds as training areas. To minimize false positives, the pre- and post-event results are compared and only those pixels with a probability of water increase are considered as flooded areas. The ability of the RF model to detect water surfaces is demonstrated (mean accuracy = 0.941, standard deviation = 0.048) along the 19 events. Validating using optical imagery (Sentinel-2 MSI) reduces accuracy to 0.642. This form of validation can only be applied to a single event using a S2 image taken 3 days before the S1 image. A large number of false negatives is then expected. A procedure developed to correct for this error gives an accuracy of 0.886 for this single event. Another form of indirect validation consists in relating the area flooded in each event to the amount of rainfall recorded. An RF regression model using both rainfall metrics and season of the year gives a correlation coefficient of 0.451 and RMSE = 979 ha using LOO-CV. This result shows a clear relationship between flooded areas and rainfall metrics.

The little fire ant (Wasmannia auropunctata), notable for its minute size and painful sting, has emerged as a significant threat in Mediterranean Europe. This widespread exotic species is well-known because of its invasive nature, impacting biodiversity, public health, and economic activities. Noted for the first time in Málaga (S Spain) in 2018, it has since expanded to other locations in the same province. Here we report the presence of W. auropunctata in La Marina (Alacant province, SE Spain), representing the fifth recorded population on the Iberian Peninsula and the first occurrence outside Málaga province. The species was found infesting a coastal area of approximately 5.1 hectares, with workers being observed in foraging trails across multiple surfaces and living in dense concentrations both indoors and outdoors. Exclusion of native ant species within the occupied area and direct engagement in combat with other species was observed. The population was discovered in September 2024; however, based on infestation density, spatial extent, and comparison with data of other Mediterranean exotic populations, the species likely established in the region prior to 2019. For the first time in Iberia, W. auropunctata was also detected in the coastal dunes adjacent to the infested urbanised area, highlighting its potential adaptability to dry Mediterranean habitats. The resilience of W. auropunctata, combined with its aggressive invasive traits and propensity to sting, underscores the urgent need for integrated management strategies to limit further expansion of the species in Iberia.

Abstract This paper describes the incorporation mechanism of Ni, Co and Cu in zoned marcasite-pyrite (FeS2) crystals from vein-type hydrothermal mineralization in the Sierra de Orihuela (Betic Cordillera, SE Spain). Single-spot analyses and X-Ray mapping by Electron Probe Micro-Analyzer (EPMA) of zoned marcasite-pyrite grains reveal positive correlations among Ni (up to 12.8 wt%), Co (up to 4.42 wt%) and Cu (up to 7.33 wt%), and negative correlation of these elements with Fe. In contrast, nanoscale analysis using High-Resolution Transmission Electron Microscopy (HRTEM) shows that these compositional variations result from a combination of solid solution and mineral nanoparticles of Ni, Co and Cu. The cores of the zoned grains are marcasite, which is depleted in Ni, Co, Cu and other trace metals. Cores are surrounded by zoned rims that contain inner portions with nanoscale zoning defined by alternating layers (∼500 nm thickness) of pyrite (FeS2) with cattierite (CoS2) and/or carrollite (CuCo2S4). This transitions to outer portions exhibiting Pa3 pyrite with frequent discrete mineral nanoparticles, including 80-120 nm-sized cubic Fd3¯m carrollite (CuCo2S4), tetragonal I4¯2d chalcopyrite (CuFeS2) and cubic Fd3¯m violarite (FeNi2S4). The shift in the mode of Ni, Co and Cu occurrence, from incorporation via solid solution to nanoparticles, reflects variations in the physicochemical conditions of the crystallizing system rather than the specific nature of the crystalline mineral matrix forming the zoned structure. The formation of the zoned structure begins with the initial crystallization of trace element-poor cores of marcasite. This is followed by pyrite rims displaying an outward progressive enlargement of the crystal lattice due to the incorporation of Ni, Co and Cu in solid solution, reaching characteristic d-spacings of carrollite and cattierite. Finally, direct precipitation of pyrite and Ni-Co-Cu-rich nanoparticles when pH increased, and salinity decreased. Nanoscale insights from Sierra de Orihuela mineralization provide an unprecedented view on the partitioning of Ni, Co and Cu into Fe-sulfides. These findings reveal mechanisms of metal enrichment in hydrothermal systems invisible to conventional tools applied to the study of mineral deposits.

Soils are a key element in the hydrological cycle through a number of soil properties that are complex to estimate and exhibit considerable spatial variability. Therefore, several techniques have been proposed for their estimation and mapping from point data along a given study area. In this work, four machine learning methods: Random Forest, Support Vector Machines, XGBoost and Multilayer Perceptrons, are used to predict and map the proportions of organic carbon, clay, silt and sand in the soils of the Campo de Cartagena (SE Spain). These models depend on a number of hyperparameters that need to be optimised to maximise accuracy, although this process can lead to overtraining, which affects the generalisability of the models. In this work it was found that neural networks gave the best results in validation, but on the test data the methods based on decision trees, random forest and xgboost were more accurate, although the differences were generally not significant. Accuracy values, as usual for soil variables, were not high. The RMSE values were 8.040 for SOC, 7.049 for clay, 10.227 for silt and 13.561 for loam. The layers obtained were then used to obtain annual curve number layers whose ability to reproduce runoff hydrographs was compared with the official CN layer. For high flow events, the CN layers obtained in this study gave better results (NSE=0.807, PBIAS=-4.7 and RMSE=0.4) than the official CN layers (NSE=-2.28, PBIAS=135.82 and RMSE=1.8).

A study of a Middle Miocene series (lower Langhian–Serravalian) in the El Bellical Basin (Almería) has revealed evidence of an ancient rocky coastline. This conclusion is supported by the discover of bioerosive structures on numerous boulders and pebbles from various conglomeratic beds. Four distinct ichnogenera have been identified: Entobia, Gastrochaenolites, Caulostrepsis, and Maeandropolydora, encompassing a total of eleven ichnospecies. These bioerosive structures were formed by clionaid sponges, lithophagous bivalves, and polychaete or spionid annelids, indicating they belong to the Entobia ichnofacies, typical of shallow, high-energy marine environments. A typical colonisation sequence was identified, beginning with clionaid sponges, followed by lithophagous bivalves, and then annelids, either contemporaneously or shortly thereafter. Additionally, some instances showed encrusting epilithozoan organisms. The conglomerate deposits further suggest the accumulation of large boulders and pebbles at the base of cliffs or as part of extensive, shallow, high-energy littoral environments with low sedimentation rates and abundant suspended nutrients. This evidence points to the existence of an ancient shoreline during the Lower Langhian–Serravalian (Middle Miocene) in this region, linked to the Mediterranean Neogene basins formed by the uplift of the Betic Cordillera and related to the extensional tectonic of this area.

Salt expulsion triggered by prograding clinoforms in the SW Valencia Trough (SE Spain)

Identifying surviving Pinna nobilis after the Mass Mortality Event (MME) in the Mediterranean: Proposal of a low-risk methodology for collecting genetic samples.