Canary Islands Research Articles

Assessing the Biogas Potential of Slaughterhouse Waste in Tenerife: A Sustainable Approach to Waste Management in an Outermost European Region

The Canary Islands, as an outermost region of Europe with fragmented territory, benefit from an exemption under Commission Regulation (EU) No 142/2011 allowing for animal by-products disposal in landfills. However, this practice has resulted in environmental and economic challenges, including reduced landfill capacity, increased greenhouse gas emissions, and missed opportunities for renewable energy production. Specifically, waste management in Tenerife faces significant challenges due to the burgeoning meat production and subsequent waste generation in its primary slaughterhouses. With an average annual production of 5,000 tons of waste, landfill capacity is nearing its limit. This study therefore aims to assess the biogas production potential from slaughterhouse waste in Tenerife and evaluate anaerobic digestion as an alternative approach. Various combinations of viscera, blood, and slaughterhouse sludge from cattle, pigs, goats, sheep, rabbits, and chickens were analyzed to determine their biogas potential. Results indicate that comprehensive valorization of these wastes could generate 12.86 GWh of energy, equivalent to approximately 20% of the energy consumed in the municipality's industrial sector. Moreover, this approach could reduce emissions by 5.88 Gg of CO2 equivalent and alleviate landfill pressures, thereby mitigating current waste management impacts. Given the region's reliance on imported fuels and limited territorial space, anaerobic digestion presents an environmentally and economically sustainable solution for managing slaughterhouse waste within a closed-loop system.

Genomic signals of adaptation to a natural CO2 gradient over a striking microgeographic scale

Our study explores genomic signs of adaptation in A. lixula to different water pH conditions. To achieve this, we analysed the genomics variation of A. lixula individuals living across a natural pH gradient in Canary Islands, Spain. We use a 2b-RADseq protocol with 74 samples from sites with varying pH levels (from 7.3 to 7.9 during low tide) and included a control site. We identified 14,883 SNPs, with 432 identified as candidate SNPs under selection to pH variations through redundancy analysis. While all SNPs indicated genomic homogeneity, the 432 candidate SNPs under selection displayed genomic differences among sites and along the pH gradient. Out of these 432 loci, 17 were annotated using published A. lixula transcriptomes, involved in biological functions such as growth. Therefore, our findings suggest local adaptation in A. lixula populations to acidification in CO2 vents, even over short distances of 75 m, underscoring their potential resistance to future Ocean Acidification.

Tourist mobility packages in an island mass tourism destination: Exploring preferences heterogeneity and willingness-to-pay

Ensuring a sustainable and efficient transportation system meeting visitor mobility needs is paramount for mass tourist destinations. Recognising this challenge, some destinations are embracing Mobility as a Service (MaaS) solutions as a strategy to create a more sustainable transportation system for tourists. This study uses a discrete choice experiment to analyse tourists’ preferences and willingness to pay for MaaS packages in two well-known municipalities of the Canary Islands, one of Europe’s premier mass tourism destinations. The empirical evidence of taste heterogeneity revealed by the analysis indicates that a one-size-fits-all solution is inadequate. Therefore, the development of mobility packages must be tailored to the specific needs of distinct tourist segments. This approach caters to individual preferences and maximises the perceived value for each tourist segment, promoting the adoption of sustainable transportation options.

On the presence of Solenocera membranacea (Decapoda, Dendrobranchiata, Solenoceridae) in the Canary Islands

Abstract We confirm the presence of the shrimp Solenocera membranacea (Risso, 1816) (Solenoceridae) in the Canary Islands. In this region, the species was only known from the capture of a specimen on the island of Lanzarote. The present finding based on a male collected on the island of Tenerife represents the second record. The data suggest that the species may be preferentially associated with soft mobile substrates, especially muddy ones, on continental shelves and upper slopes, while its presence on the hard bottoms of the volcanic archipelagos of Macaronesia would be testimonial.

Genetic and biological insights into Hydatigera taeniaeformis in invasive black rats from southern Chile

IntroductionThis study investigates the genetic variability of Hydatigera taeniaeformis in black rats (Rattus rattus), a common tapeworm that infects cats and rodents worldwide. Despite its widespread presence and zoonotic potential, little is known about the genetic diversity of this parasite in the Americas.MethodsWe conducted DNA barcoding analysis using mitochondrial cox1 gene sequences using samples collected from 171 invasive wild black rats, captured in the temperate rainforest of Southern Chile. We also included two adult parasites isolated from road killed Kodkods (Leopardus guigna), a small felid species native to the Americas.ResultsOur findings revealed only two haplotypes, suggesting low genetic variability in a parasite that arrived in the Americas with the Spanish colonization.DiscussionThese haplotypes are more closely related to parasite populations from Peru, Africa, Australia, and Europe, suggesting an origin linked to the Spanish colonization, possibly from North Africa via the Canary Islands. The study also analyzed infection rates, parasite size, and their correlation with host body size, age, and weight, revealing significant patterns. These results provide new insights into the biogeography and genetic diversity of H. taeniaeformis in a new geographical area, enhancing our understanding of its evolutionary history.

The Canary Islands, an Imperial Frontier: Decolonial Thought in South-South Relations in Northwest Africa

The Canary Islands, an Imperial Frontier: Decolonial Thought in South-South Relations in Northwest Africa

3-D intrinsic attenuation tomography using ambient seismic noise applied to La Palma Island (Canary Islands)

The potential of the island of La Palma (Canary Islands) to host geothermal resources is very high, mainly due to its high volcanic activity. The primary goal of this study is to get a tridimensional image of the seismic intrinsic attenuation using ambient seismic noise and to identify anomalies that may be linked to active geothermal reservoirs on La Palma island. For this purpose, we developed a new Ambient Noise Attenuation Tomography (ANAT) technique, which uses seismic ambient noise for imaging intrinsic attenuation in 3-D at a local scale down to 5 km depth. Our research identifies two areas with high attenuation in the island’s southern region. One area could be associated with hydrothermal alteration zones beneath the Cumbre Vieja volcanic complex. Another high-attenuation zone was observed in the island’s southern part, which could be associated with extensively fractured rocks that might facilitate the circulation of heated fluids. Furthermore, we discuss the geothermal relevance of such anomalies, making a comparison with previous resistivity, S-wave velocity and density models. This study confirms that intrinsic attenuation retrieved from the coda of Rayleigh waves is more sensitive to the presence of fluids than velocity. Fluids being a key component of active geothermal reservoirs, it is reasonable to expect intrinsic attenuation anomalies in these systems. Therefore, we conclude that ANAT can be useful for geothermal exploration.

Biocontrol Potential of a Native Trichoderma Collection Against Fusarium oxysporum f. sp. cubense Subtropical Race 4

The Canary Islands lead banana (Musa acuminata) production in the EU. Different fungal pathogens affect this crop in subtropical areas, with Fusarium oxysporum f. sp. cubense subtropical race 4 (Foc-STR4) being the most important in the Canary Islands. With the aim of developing environmentally sustainable techniques for disease control, this study presents the results of the evaluation of the antifungal capacity of a native Trichoderma collection (12 species, 109 isolates) obtained from banana soils. The results demonstrate the diversity of biocontrol genes and the in vitro antagonistic potential of different native Trichoderma species/isolates against two Foc-STR4 strains obtained from plants with Panama disease symptoms. Trichoderma virens (TF18), a dominant species in banana soils in the Canary Islands, showed a high capacity to inhibit the growth of Foc-STR4 in different in vitro assays. Trichoderma atrobrunneum (TF01) showed mycoparasitism capacity through the spiral coil around the hyphae of the pathogen. In addition, the genome analysis of T. atrobrunneum (TF03) showed 69 putative biosynthetic gene clusters, with the notable presence of the trichothecene tri5 gene. Finally, our work demonstrates that the soils of the Canary Islands banana crops are a potential source of environmentally adapted biological control agents to control or reduce the incidence of Foc-STR4.

German Intelligence during the Second World War: The Canary Islands as a Case Study

German Intelligence during the Second World War: The Canary Islands as a Case Study

Volcanic Terroirs: Exploring Minerals in Canary Red Wine

The mineral composition of monovarietal red wines from the Canary Islands was analyzed to evaluate the potential of mineral content as a marker for wine authenticity by geographical origin. Key minerals—K, Na, Mg, Mn, Fe, Cu, and Co—were quantified in 190 wine samples using flame absorption spectrometry. The study revealed slight mineral profile differences between recently introduced international grape cultivars and traditional ungrafted varieties. A significant correlation was found between K and Mg, highlighting their roles in vine physiology. The results indicated that Tenerife wines had elevated Fe and Mn, Lanzarote wines showed higher Na (likely from marine aerosols), and La Gomera wines had significantly high Mn. Linear discriminant analysis demonstrated that Mn, Mg, and Na differentiated wines by island with 85% classification accuracy, while Cu and Fe correlated with wine ageing. These findings emphasize the influence of volcanic soils and microclimate on mineral profiles, supporting mineral analysis as a cost-effective tool for classifying red wines by origin. This study offers insights into how terroir, grape cultivar, and winemaking practises define the unique characteristics of Canary Island wines.

Oceanic islands act as drivers for the genetic diversity of marine species: Cardita calyculata (Linnaeus, 1758) in the NE Atlantic as a case-study

Geographic distribution, as well as evolutionary and biogeographic processes and patterns of marine invertebrate benthic species are strongly shaped by dispersal ability during the life cycle. Remote oceanic islands lie at the brink of complex biotic and abiotic interactions which have significantly influenced the biodiversity patterns we see today. The interaction between geological environmental change and taxon-specific dispersal modes can influence species evolutionary patterns, eventually delimiting species-specific biogeographic regions. In this study, we compare the population genetic patterns of the marine bivalve Cardita calyculata in the northeast Atlantic, discussing the role of Macaronesian islands during past climatic cycles. The genetic structure and diversity patterns were outlined based on SSR-GBAS loci of 165 individuals and on the mitochondrial COI marker of 22 individuals from the Canary Islands, Madeira, Azores and the Mediterranean. The highly structured genetic pattern found among regions and within archipelagos suggests the central role of oceanic islands in promoting the divergence of the species in both the NE Atlantic and the Mediterranean. The high degree of divergence in the COI dataset (> 7%) suggests the existence of potential cryptic speciation that needs to be further explored with a more comprehensive sampling. Such patterns are only congruent with a scenario where C. calyculata populations were maintained during glacial/interglacial cycles, supporting the role of the studied archipelagos as drivers of diversity for marine biota. We stress the importance of developing studies for species with various life history and dispersal modes. In such a way, a more profound understanding of the biogeographic and evolutionary significance of oceanic islands can catalyse directed conservation efforts, especially in the context of the ongoing climate crisis.

Refinement of the volcanic slope rating approach for determining slope stability in volcanic rocks of the Canary Islands

AbstractDue to their genesis, volcanic rocks present some singularities that make their geotechnical characteristics significantly different from other, more common types of rock masses, such as sedimentary and metamorphic rocks. The formation mechanisms of volcanic rocks are varied, rapid and generally high energy. These processes give this type of rock geotechnical behaviour and geomechanical properties that are completely different from those of nonvolcanic materials, due to their high heterogeneity and anisotropy. In volcanic rock slopes, applying widely used geomechanical classifications to assess the quality of any rock mass present several challenges due to their distinctive and singular characteristics, which detract from their validity. For this reason, the Center for Studies and Experimentation of Public Works (CEDEX) of the Ministry of Public Works, under the agreement signed with the Ministry of Public Works and Transport of the Government of the Canary Islands, carried out during 2017 and 2018 an exhaustive analysis and reviews of existing geomechanical classifications and their applications to volcanic terrains. They developed a new geomechanical classification called VSR (volcanic slope rating), based on data obtained from 85 slopes across the Canary Islands, which allowed for the estimation of the stability of volcanic rock slopes by evaluating seven geotechnical parameters. This article presents the work conducted to review and calibrate this tool, based on the study of 94 slopes of different lithotypes throughout the Canary Islands (lavas, pyroclasts, heterogeneous), culminating in the proposal of a new classification for pyroclastic massifs (with new parameters and different weightings) and the adjustment of the current classification for the other slopes (regarding the Surface Regularity parameter). Therefore, the VSR geomechanical classification was applied to assess the stability of these 94 slopes, revealing a strong fit for Types A and C (R2 > 0.97), while the tool overestimated stability in Type B slopes, prompting a new classification proposal for this category.

The physical properties of two potential targets for space missions: (155140) 2005 UD and (612267) 2001 SG286

Abstract The ground-based characterization of asteroids is a key step for planning their exploration. The near-earth asteroid 155140 (2005 UD) is a potential flyby target of JAXA’s DESTINIY+ mission, while (612267) 2001 SG286 has been considered as a possible target for in-situ exploration. We aim to determine their physical properties using the observations obtained with various telescopes from Canary Islands Observatory. For 2005 UD we confirmed the two peak lightcurve, a rotation period of 5.224 ± 0.003 h and an amplitude of 0.34 mag. However, a three peak solution seemed also to fit the light-curve, but this was discarded as implausible. Using the obtained visible to near-infrared spectrum we classified it as a Cb-type, and we found a spectral matching with heated carbonaceous chondrite meteorites of CM2 type. The thermal emission flux at 2.2 μm points to an albedo of pV = 0.06 ± 0.02. There are significant differences in the spectrum of 2005 UD compared to that of (3200) Phaeton, hypothesized as its parent body. The accurate visible spectrum obtained with the GTC indicate that 2001 SG286 is an S-type asteroid. The photometric data obtained with INT suggests a rotation period of 12.30 ± 0.01 h and an amplitude of 0.64 mag. With these observations we found its absolute magnitude H = 21.4 ± 0.3, and estimate its size as 160 ± 45 m.

Composition of inshore ichthyoplankton community in the Canary islands from a spatial and seasonal perspective: Inshore ichthyoplankton of the Canary Islands

Early life stages of fish are insufficiently studied in most regions around the globe, and consequently, there is an important gap in knowledge on the life cycle of most teleosts. In the Canary Islands (Eastern Central Atlantic), most studies on ichthyoplankton communities are based on traditional net tows in open waters that provide information about early larval stages of pelagic species in the area, while nearshore benthic fish remain highly understudied. In this study, light traps were employed for the first time to assess post-larval stages of neritic fish in this archipelago. A two-year survey was carried out to collect nearshore fish larvae every 6 months at 11 localities from El Hierro, Tenerife and Lanzarote. A total of 3940 fish larvae classified into 13 orders, 28 families and 44 species were collected. These results provide a wide description of the composition of the inshore ichthyoplankton off the Canary Islands, across islands and seasons. Main environmental factors (SST, sea floor orography, oceanographic phenomena …) influencing the population dynamics of this community are discussed. Additionally, the ichthyoplankton assemblages were assessed from the intra-annual perspective, analyzing the species composition and abundances by months and seasons, and providing new insights into reproduction cycles of many common benthic fishes at shallow marine ecosystems of the islands. This study is important to further understand the life cycles of some of the most common fish species in the Canary Islands, unraveling main environmental factors that affect the success of their offspring that sustain populations.

Aerosol retrievals derived from a low-cost Calitoo sun-photometer taken on board a research vessel

This study presents a comprehensive 5-year period assessment of aerosol optical depth (AOD) and Å ngströn Exponent (AE) data from a hand-held Calitoo sun photometer on board the Ángeles Alvariño research vessel. Observations spanned March 2018 to September 2023, focusing on key maritime regions such as the Canary Islands, coasts of North Africa, the Mediterranean, Portugal, the Cantabrian, and the Bay of Biscay. The Calitoo device measures solar irradiance at three wavelengths (465, 540, and 619 nm). Uncertainty analysis for Calitoo AOD retrievals was performed using the Monte Carlo method, yielding an expanded uncertainty (UAOD) ranging between 0.008 and 0.050 with a mean and standard deviation of 0.032 ± 0.008 for the three wavelengths. Our results also highlight the remarkable calibration stability of the Calitoo (< 2.6%) over this 5-year period. Calitoo AOD values were assessed using reference AOD data from Santa Cruz de Tenerife (the Canary Islands), El Arenosillo (Huelva), and Palma de Mallorca (the Balearic Islands) AERONET (Aerosol Robotic Network) stations. The comparison revealed a good agreement with correlation coefficients ranging from 0.727 to 0.917 and mean bias ranging from -0.030 to -0.001. Additionally, the Calitoo AOD data were compared with MODIS (Moderate Resolution Imaging Spectroradiometer) and CAMS-ECMWF (Copernicus Atmosphere Monitoring Service-European Centre for Medium-Range Weather Forecasts) aerosol products obtaining that Calitoo AOD values were generally lower, showing negative mean bias of -0.063 and -0.024, respectively.The aerosol characterizations using AE vs. AOD plots in the three maritime study regions using 5-years of non-routine Calitoo data are similar to the corresponding aerosol characterizations performed with simultaneous AERONET-Cimel data.These findings underscore Calitoo’s reliability for aerosol studies in regions where AERONET instruments or other aerosol networks are unavailable. Likewise, given the low cost of Calitoo photometers, they could be deployed onboard a large number of merchant and passenger ships or in other remote or under-monitored areas, providing near real-time AOD/AE data to enhance our understanding of aerosols processes or for model or satellite assimilation/validation.

Taphonomy on the beach: experimental approach to bone modifications made by insects on an island (Gran Canaria, Canary Island, Spain)

Taphonomy on the beach: experimental approach to bone modifications made by insects on an island (Gran Canaria, Canary Island, Spain)

Sharing the ocean: fostering blue synergies for sustainable whale-watching

Whale-based tourism activities offer unique opportunities for humans to observe cetaceans in their natural habitats. Well-planned experiences can provide educational value and promote respectful enjoyment of marine wildlife. Conversely, poorly managed activities can negatively impact cetaceans by injuring or killing them (through collisions with boats) or altering their behavior, such as resting time, nursing or diving. This study presents an example of designing and implementing a whale-based tourism activity in the Canary Islands (Spain), with the participation of researchers, whale-watching operators and tour guides, public policy-makers, and civil society, with a strong focus on educational values. The coastal communities are crucial in promoting sustainable whale-watching practices through educational initiatives, community engagement, and stakeholder collaboration. The paper employs a process-monitoring approach to evaluate the whole procedure of whale-watching activity implementation. We assume that the success of any tourism activity depends on the process that leads to its creation. The analysis emphasizes the need for careful planning and execution to design and implement marine tourism experiences. Concerns for tourism satisfaction and safety and the need for environmental sustainability challenge the management of whale-watching operations. In this regard, engaging local communities, addressing safety and conservation concerns, and promoting responsible tourism practices are essential for mitigating these challenges and ensuring the long-term viability of whale watching as a sustainable and educational activity.

Academic and Employment Preferences of Nursing Students at the University of Las Palmas of Gran Canaria: A Cross-Sectional Study

Background/Objectives: It is well known that there are differences in the academic and employment preferences of nursing students once they have completed their undergraduate studies in nursing. These preferences are largely influenced by students’ affinity for certain thematic areas over others. Therefore, the objective of this study was to identify the employment and academic preferences of third- and fourth-year Nursing Degree students at the University of Las Palmas de Gran Canaria (ULPGC). Methods: A cross-sectional, descriptive observational study was conducted among nursing students across three campuses of the ULPGC (Canary Islands, Spain). An online questionnaire was used to collect various sociodemographic and academic variables, as well as preferences across ten thematic areas. Descriptive and bivariate inferential analyses were performed, along with a correlation analysis among the areas. Results: The areas of highest preference were “Emergency Nursing”, “General Nursing”, and “Family and Community Nursing”. The areas of lowest preference were “Other Areas (teaching, management, research)”, “Mental Health and Psychiatric Nursing”, and “Geriatric Nursing”. Three clusters of closely correlated areas were identified: cluster 1 (Intensive and Critical Care Nursing, Emergency and Emergency Nursing and Operating Theatre and Anaesthesia Nursing), cluster 2 (Obstetric-Gynaecological Nursing–Midwifery, Paediatric Nursing and Mental Health and Psychiatric Nursing) and cluster 3 (remaining areas). A significant proportion of students expressed intentions to pursue postgraduate studies. Conclusions: Strategies should be implemented to enhance students’ preferences in the areas of “Mental Health and Psychiatric Nursing” and “Geriatric Nursing”, which are areas where there is a high demand for nurses. It is also necessary to increase their interest in research, management, and teaching. This study was not registered.

Global tsunami modelling on a spherical multiple-cell grid

A model of shallow water equations (SWEs) on a spherical multiple-cell (SMC) grid of 4-level (2.5-5-10-20 km) spatial resolutions is used to simulate tsunami propagation on global ocean surfaces. The unstructured SMC grid retains rectangular cells of the longitude-latitude grid so that efficient finite-difference schemes could be used. It also supports multi-resolutions like mesh refinement to resolve small islands and coastline details while keeping models compact enough to fit into available computers. Two earthquake-induced tsunami cases are simulated and compared with available observations. Results indicate that the modelled tsunami arrival times agree well with observations while tsunami wave heights are underestimated, particularly the observed runups on remote coastal lands. Possible reasons for this underestimation include the smoothing scheme used to suppress numerical oscillations and the missing of initial kinetic energy input from the earthquakes. Another reason is the limitation of the SWEs to describe coastal bores and breaking waves in coastal waters. A possible tsunami scenario induced by a landslide in the Canary Islands is also simulated to assess its potential impact on Atlantic coastal regions. Model results indicate that this kind of tsunami may cause severe damage to local areas but its effects on far fields, like the UK and American coastal regions are small. As the initial landslide disturbance is overly simplified, this study does not give a true representation of a real landslide tsunami but rather a qualitative assessment of its impact on the Atlantic Ocean. More realistic initial condition and improved model representation of coastal processes are needed for further studies of this possible landslide hazard.

Predicting the future distribution of the Barbary ground squirrel (Atlantoxerus getulus) under climate change using niche overlap analysis and species distribution modeling.

This study combines niche overlap analysis with species distribution modeling (SDM) to examine the niche dynamics of Atlantoxerus getulus, a ground squirrel native to Morocco and Algeria that has been introduced to the Canary Islands. We compiled 1272 records of A. getulus in its native and exotic ranges and five bioclimatic variables for present and future climate conditions for the years 2050 and 2070. We assessed the ecological niche of the species using exploratory and ordination analyses, followed by the prediction of its distribution using the SpatialMaxent model. Our results showed that the niches of A. getulus exhibited equivalence (p > 0.05) and significant similarity (p < 0.05) between the native and exotic ranges. No observed niche expansion in the exotic area is shown to be associated with complete niche stability. However, 90% of the niche in the Canary Islands remains unfilled, suggesting potential for further invasion. Our results highlighted habitat contractions ranging from 41% (SSP245-2050) to 60% (SSP585-2070), associated with a shift in the centroid of suitable habitat towards the Atlantic coast. These contractions are particularly severe in Algeria, where suitable habitats could disappear by 2050, contrasting with stable habitats maintained in the Canary Islands under all scenarios. Urgent habitat restoration in Algeria is crucial, including efforts to combat poaching. In Morocco, targeted in situ conservation is recommended, while in the Canary Islands, the focus should be on invasive species management and public awareness campaigns to prevent further spread.