Southern Tenerife Research Articles

High macrolides and fluoroquinolones resistance rate in Mycoplasma genitalium in southern Tenerife

Mycoplasma genitalium (MG) is a recognized sexually transmitted pathogen. Increasing resistance to main lines of treatment (macrolides and quinolones) justifies a genetic study of mutations to improve cure rates. A total of 8,508 samples from April 2018 to July 2022 were processed using AllplexTM STI Essential Assay. In MG positive cases 23S rRNA V domain, gyrA and parC genes were studied. Mutations detected were checked to assess their clinical significance and medical records were reviewed to obtain demographic and treatment information. Resistance study was performed on 92 samples (65 men and 27 women). In relation to the genotypic study, 28 patients presented mutations to macrolides (30.43%). Most common was A2059G (18.48%). For quinolones, 5 patients (5.43%) had clinically relevant mutations in parC gene. Of note was a patient with G295 mutation in gyrA associated with G248T in parC. Thirty subjects underwent a test of cure (TOC). Azithromycin was the most common empirical regimen and moxifloxacin the main alternative. High rate of resistance in our environment evidences the need for targeted therapy by genotypic study of macrolide resistance, supported by the detection of mutations in parC and gyrA to predict quinolones susceptibility and the use of TOC to evaluate treatment response.

The upper Pleistocene (1.8–0.7 Ma) explosive eruptive history of Las Cañadas, ocean-island volcano, Tenerife

While most ocean-island volcanism is effusive, recent evidence has demonstrated that intraplate ocean island volcanoes can exhibit protracted explosive histories, with catastrophic eruption styles and hazardous behaviour more typically associated with volcanoes in continental and plate-margin settings. Tenerife is the largest explosive ocean-island volcano on Earth, with a prolonged (∼2 Ma) post-erosional history of caldera-forming, plinian and ignimbrite eruptions of evolved composition. The 0.7–1.8 Ma succession with 20 newly defined formations is reported for southern Tenerife, Canary Islands. In the last 2 Myr, the Las Cañadas volcano has produced >42 pumice-fall eruptions, 21 with extensive ignimbrites, and 12 inferred caldera collapse events. Pyroclastic density currents have repeatedly travelled more than15 km from source to the ocean, filling valleys and burying extensive interfluves. A robust whole-rock chemistry dataset, selected mineral chemistry, coupled with new 40Ar/39Ar ages of units through the pyroclastic stratigraphy, allow recognition of magmatic trends within the system on the order of 100 ky. The catastrophic explosive eruptions form three, 0.2–0.5 Myr-duration clusters (the Ucanca, Guajara and Diego-Hernandez) that do not appear to correspond simply with geochemical cycles, or to cycles of increasing eruption size or explosivity as has been previously proposed. During the clusters, large eruption frequencies averaged 1 every 20–45 kyrs. The eruption clusters were separated by hiatuses of ∼240–260 kyr, recorded by soils and unconformities, and may reflect marked changes in geographic dispersals following giant landslide breaches in Las Cañadas caldera wall. Two concurrent evolutionary magmatic trends are distinguished: one producing crystal-rich magmas, the other formed the cooler crystal-poor magmas: both spanned over a million years until 0.66 Ma, when the former ceased.

Organochlorine pesticides and polychlorinated biphenyls in common kestrel eggs from the Canary Islands: Spatiotemporal variations and effects on eggshell and reproduction

Organochlorine (OC) pesticides were widely used on the Canary Islands (Spain) for intensive crop production and against plagues of African locust. A previous study performed in 1988–1994 showed a high concentration of p,p’-DDE in the eggs of common kestrels (Falco tinnunculus) from the island of Tenerife. The present study shows OC pesticide and polychlorinated biphenyl (PCBs) levels in 40 unhatched common kestrel eggs collected from southern Tenerife between 2009 and 2016. The protoporphyrin IX in eggshells has also been analysed in order to explore the use of this pigment as a biomarker. Egg biometry, status of embryo development, eggshell thickness and mass of extractable lipids of each egg were recorded. Surrounding land use and reproductive parameters (hatching and fledging rates) were obtained for each nest. The most abundant compound was p,p’-DDE (15.0 μg/g d.w), followed by PCBs (0.46 μg/g d.w.). The decline in p,p’-DDE levels in southern Tenerife (with 23.6 μg/g d.w. in 1988–1994) was 36.4%. p,p’-DDE levels were positively associated with the surface of active and abandoned cropland in a 200 m-radius around the nest and with proximity to urban areas. PCB levels were associated with proximity to roads. Shell thickness was negatively affected by the p,p’-DDE concentration. The concentration of protoporphyrin IX in the eggshell was negatively associated with the concentration of hexachlorobenzene in the egg content. Despite the total ban on the use of p,p’-DDT in Spain since 1986, p,p’-DDE levels remain elevated in those areas in which that use was formerly intensive.

Compositional variability of Pleistocene land snail assemblages preserved in a cinder cone volcano from Tenerife, Canary Islands

A Pleistocene land snail rich scoria sequence was studied to determine if it was influenced by taphonomic bias, climate change, or both, using a multifaceted approach that combines taphonomic, ecological, body size, and stable isotope data. Shell assemblages were sampled from two layers (Units A and B) in a cinder cone volcano of southern Tenerife (Canary Islands), dated to the glacial interval MIS 8 (~299–302ka). The two units differed in taphonomy, species composition, and abundance, with the upper Unit B showing higher diversity, abundance, and lower alteration than the lower Unit A. Larger bodied species dominated Unit A and were better preserved than smaller species. These mismatches likely resulted from physical differences in the sediment matrix surrounding fossils, with larger scoria grains of Unit A enhancing destruction rates and thus favoring preservation of larger (more durable) taxa than smaller scoria grains of Unit B. Comparisons with modern assemblages from the coastal scrub, the plant biome in which the Pleistocene site currently resides, indicates that no modern analogue exists for these fossil assemblages within this biome. Shell oxygen isotope values reveal that the local climate was colder/wetter during MIS 8 than at present, which also may explain variations in species composition through time. These data suggest that both taphonomic and climatic factors appear to have induced temporal variations in taxonomic composition, but it is difficult to determine which of these has more significantly influenced the observed results.

Morbillivirus and Pilot Whale Deaths, Canary Islands, Spain, 2015

Morbillivirus and Pilot Whale Deaths, Canary Islands, Spain, 2015

An updated and refined Holocene uplift history of southern Tenerife (Canary Islands) and the possible consequences for future volcanic activity

AbstractVarious uplift markers suggest asymmetrical uplift of Tenerife Island, with stable conditions in the north but significant uplift of up to 45 m in the south over the past ~42 ka. Fossil shells in beach deposits uplifted by 7.5–9 m were14C-dated at a Holocene age of 2460±35bp(1σ). This confirms earlier results and documents very young, and probably still ongoing, uplift of southern Tenerife potentially caused by ascending magma. This underlines that southern Tenerife is probably undergoing a further cycle of volcanic activity that started ~95 ka ago.

Mesorhizobial strains nodulating Anagyris latifolia and Lotus berthelotii in Tamadaya ravine (Tenerife, Canary Islands) are two symbiovars of the same species, Mesorhizobium tamadayense sp. nov.

Barranco de Tamadaya is a deep ravine located in southern Tenerife, which is included within a protected area where several endemic plants grow. Among them, two legumes are catalogued as critically endangered, Anagyris latifolia and Lotus berthelotii. Rhizobial strains isolated from their root nodules grown in soil samples from this ravine harboured symbiotic genes belonging to two distant symbiovars, but they shared identical 16S rRNA gene sequences (rrs). The phylogeny based on the rrs sequences placed these isolates in a separate subbranch that did not include any of the currently recognised Mesorhizobium species, but the resolution of the ribosomal tree did not permit further taxonomic conclusions. Nevertheless, multilocus sequence analysis (MLSA) of four housekeeping genes (atpD, recA, glnII and dnaK) and the rrs gene generated a highly supported Bayesian phylogeny, identifying these isolates as a new Mesorhizobium lineage. DNA–DNA hybridisation homology percentages were lower than 30% compared to type strains of the closest related species, and supported the phylogenetic data. Phenotypic characterisation also distinguished this lineage from the other closest Mesorhizobium species. The polyphasic approach thus confirmed that the isolates represented a novel species for which we propose the name Mesorhizobium tamadayense sp. nov. The type strain is Ala-3T (CECT 8040T, LMG 26736T).

Pleistocene forest on Tenerife's southern coast: a case study of Montaña Negra

Montaña Negra is a 121 m cinder cone in the Bandas del Sur region of southern Tenerife. Formed in the Middle Pleistocene, it comprises alternating phonolitic pumice deposits and scoria layers; the latter are extremely fossiliferous with good taphonomical fidelity. 40Ar/39Ar age determination provides new dates of 302 ± 7.6 ka and 299.9 ± 11.4 ka for the Lower and Upper Aldea Blanca pumice fall deposits, respectively. This chronological constraint allows comparison of the palaeo-habitat with the global climate at the time of pyroclastic activity. Abundant terrestrial gastropod species and rare disarticulated Coleoptera fragments are to be found. The occurrence of the endemic semi-slug genus Plutonia (Family Vitrinidae) is significant in indicating a woodland habitat in the region during the Middle Pleistocene. We suggest that this may have been forest, possibly dominated by laurel, which is in stark contrast to the present-day semi-desert. Copyright © 2011 John Wiley & Sons, Ltd.

A record of long-time rift activity and earthquake-induced ground effects in Pleistocene deposits of southern Tenerife (Canary Islands, Spain)

Faults with a well-defined strike direction that precisely coincides with the southern rift fault system occur in the study area in southern Tenerife. This fault system was generated contemporaneously with a chain of cinder cones ~948 ka. Open fractures in ignimbrites (~668 ka) and fossil beach deposits (~42 ka) of the El Medano area suggest that the rift-associated fault system was seismically active in the aftermath of the initial volcanic activity (~948 ka) and is probably still active. A second fault system striking perpendicular to the rift-related faults probably originates from a Holocene paleoearthquake of moderate intensity. Earthquake-induced ground effects in fossil beach deposits within the study area are consistent with seismically induced ground effects of several recent and well-documented earthquakes, as well as gravitational sliding triggered by an intense earthquake in the Nicoya Peninsula of Costa Rica in 1990. Both, the rift-associated and the earthquake-induced fault system, initially produced open fractures that were occupied by plants and subsequently stabilized by cementation, forming conspicuous sediment structures in fossil beach deposits of the El Medano site in southern Tenerife.

Taxonomic and nomenclatural notes onCrassulaceaeof the Canary Islands, Spain

Abstract Banares Baudet, A., Marrero Gomez, M. V. & Scholz, S.: Taxonomic and nomenclatural notes on Crassulaceae of the Canary Islands, Spain. — Willdenowia 38: 475–489. — ISSN 0511 -9618; © 2008 BGBM Berlin-Dahlem. doi:10.3372/wi.38.38208 (available via http://dx.doi.org/) Aeonium decorum var. alucense and Aichryson laxum var. latipetalum, from eastern La Gomera and southern Tenerife, respectively, are described as varieties new to science and illustrated. New combinations in Aeonium (A. arboreum subsp. holochrysum, A. canariense subsp. christii, A. canariense subsp. latifolium, A. canariense subsp. virgineum, A. lindleyi subsp. viscatum), Aichryson (A. tortuosum var. bethencourtianum) and Monanthes (M. minima subsp. adenoscepes) are validated. M. polyphylla subsp. amydros, thought to be endemic to La Gomera, is also reported for the island of La Palma. Additional descriptive data for M. wildpretii are provided. Special attention is paid to the morphological characteristics that differentiate some close...

Age distribution of cinder cones within the Bandas del Sur Formation, southern Tenerife, Canary Islands

AbstractThe Quaternary Bandas del Sur Formation in the south of Tenerife comprises a complex sequence of pyroclastic rocks and lavas. In contrast to the NW- and NE-Rift zone on Tenerife, the S-Rift zone comprises a number of characteristics with respect to the morphological features, eruption cyclicity and the geochemistry of the volcanic deposits. Various flank eruptions of the Las Cañadas volcano associated with basaltic lavas and the formation of cinder cones within the Bandas del Sur are important volcanic units for understanding the explosive volcanic cycles during the Pleistocene on Tenerife. A number of palaeomagnetic studies, as well as major and trace element geochemistry and two radio-isotope dates (K–Ar), have been carried out on prominent cinder cones, in order to discover their stratigraphic position. Combining our results with previous K–Ar data, the cones and lavas can be subdivided into three stratigraphic units. The first unit contains cinder cones with reverse magnetization and Y/Nb ratios between 0.37 and 0.41. Cinder cones which belong to the second unit show normal magnetization and Y/Nb ratios of < 0.35. The third unit comprises cinder cones with normal magnetization and Y/Nb ratios of about 0.47. The first two units were constructed between c. 0.948–0.779 Ma and 0.323–0.300 Ma. These units define volcanic cycles ending in violent Plinian eruptions. The third and youngest unit possibly marks the beginning of a further volcanic cycle that started c. 0.095 Ma ago.

Conspicuous sediment structures in fossil beach deposits (southern Tenerife, Canary Islands, Spain): paleoliquefaction features versus biogenic origin

Tubular-shaped concretions and concretionary dykes occur in Holocene fossil beach deposits between the township of El Medano and Punta Roja in southern Tenerife, Canary Islands. These sediment structures have been interpreted either as the result of (a) the interaction between hot ignimbrites that overflowed wet beaches; (b) fast accumulation of beach sands on hot and degassing ignimbrites; (c) paleoliquefaction caused by an earthquake (seismites). Based on the interpretation as seismites, an intense paleoearthquake with a moment magnitude of M = 6.8 was proposed to be responsible for the generation of the paleoliquefaction structures. However, we here reinterpret the sedimentary structures in question using the general criteria diagnostic for rhizocretions and root tubules with respect to their orientation, size, branching system, and style of cementation and, thus, consider them, to be of biogenic origin.

Degradation of an arid coastal landscape in relation to land use changes in Southern Tenerife (Canary Islands)

The results of the first study of land use changes between 1964 and 1992 in Southern Tenerife (Canary Islands) are presented and discussed in relation to the general socio-economic processes and the current nature conservation policy. The analysis of five main land use types with a geographic information system (GIS) revealed that the arid coastal landscape has been dramatically transformed during the past decades due to the increase of mass tourism and the intensification of agriculture, resulting in a large-scale destruction of the coastal scrub, the natural, endemic-rich vegetation. Between 1964 and 1992, the area occupied by irrigated crops increased strongly due to the transition from tomato to banana production. During the same period of time, the amount of abandoned farmland as well as the area used for housing and infrastructure increased markedly, the latter by more than 20 times. In nature reserves, most of the natural vegetation has survived but only in a degraded state, mainly due to recreation activities and illegal waste dumping. In unprotected areas, by contrast, 60% of the natural vegetation was lost between 1964 and 1992, and 86% of the native vegatation of recent lava flows. The results show that the current practice of protecting comparatively small natural areas is not sufficient to stop the massive destruction of natural vegetation. Surprisingly and disturbingly, there is evidence, that a substantial part (40%) of these losses could easily have been avoided by better environmental planning.

Pole Position: Migrant British Women Producing ‘Selves’ through Lap Dancing Work

This paper explores the motivations and experiences of British women working as lap dancers in the tourist resorts of southern Tenerife, with a particular focus on the subjective choices and processes undertaken by working-class women in the embodiment of positively evaluated identities. It uses Skeggs’ theoretical framework of ‘becoming respectable’ (1997) alongside other debates on ‘identity management’ in order to begin mapping the ways in which migrant British lap dancers produce themselves, negotiate gender and class, and seek forms of respectability, reputability and honour through their work. Drawing on empirical data, it will discuss how strong disassociations with the Other are formed, and how and why important binaries, particularly distinctions between lap dancing and prostitution and lap dancing and other ‘degraded’ forms of work and lifestyle are drawn in the dancers’ own stories of themselves. It will look at notions and processes of gaining ‘respectability’ through part of a wider migrant discourse, exploring how being a migrant lap dancer can serve as a vehicle for reproducing a ‘respectable’ and otherwise positively evaluated self on several levels.

The Quaternary pyroclastic succession of southeast Tenerife, Canary Islands: explosive eruptions, related caldera subsidence, and sector collapse

A much-revised Quaternary stratigraphy is presented for ignimbrites and pumice fall deposits of the Bandas del Sur, in southern Tenerife. New 40Ar/39Ar data obtained for the Arico, Granadilla, Fasnia, Poris, La Caleta and Abrigo formations are presented, allowing correlation with previously dated offshore marine ashfall layers and volcaniclastic sediments. We also provide a minimum age of 287±7 ka for a major sector collapse event at the Güimar valley. The Bandas del Sur succession includes more than seven widespread ignimbrite sheets that have similar characteristics, including widespread basal Plinian layers, predominantly phonolite composition, ignimbrites with similar extensive geographic distributions, thin condensed veneers with abundant diffuse bedding and complex lateral and vertical grading patterns, lateral gradations into localized massive facies within palaeo-wadis, and widespread lithic breccia layers that probably record caldera-forming eruptions. Each ignimbrite sheet records substantial bypassing of pyroclastic material into the ocean. The succession indicates that Las Cañadas volcano underwent a series of major explosive eruptions, each starting with a Plinian phase followed by emplacement of ignimbrites and thin ash layers, some of co-ignimbrite origin. Several of the ignimbrite sheets are compositionally zoned and contain subordinate mafic pumices and banded pumices indicative of magma mingling immediately prior to eruption. Because passage of each pyroclastic density current was characterized by phases of non-deposition and erosion, the entire course of each eruption is incompletely recorded at any one location, accounting for some previously perceived differences between the units. Because each current passed into the ocean, estimating eruption volumes is virtually impossible. Nevertheless, the consistent widespread distributions and the presence of lithic breccias within most of the ignimbrite sheets suggest that at least seven caldera collapse eruptions are recorded in the Bandas del Sur succession and probably formed a complex, nested collapse structure. Detailed field relationships show that extensive ignimbrite sheets (e.g. the Arico, Poris and La Caleta formations) relate to previously unrecognized caldera collapse events. We envisage that the evolution of the nested Las Cañadas caldera is more complex than previously thought and involved a protracted history of successive ignimbrite-related caldera collapse events, and large sector collapse events, interspersed with edifice-building phases.

Paleoearthquake evidence in Tenerife (Canary Islands) and possible seismotectonic sources

A series of clastic dikes and tubular vents were identified in southern Tenerife (Canary Islands). These features are the result of seismic liquefaction of a Holocene sand deposit, as the consequence of a high intensity paleoearthquake. The peak ground acceleration (pga) and magnitude of the paleoearthquake generating these liquefaction features were estimated by back calculation analysis. A representative value of 0.30 ± 0.05 g was obtained for the pga. From this, an earthquake intensity of IX was estimated for the liquefaction site. Magnitude bound methods and energy based approaches were used to determine the magnitude of the paleoearthquake, providing a moment magnitude M = 6.8. The zone in which the liquefaction structures are found has undergone tectonic uplift and is affected by two faults. One of these faults was responsible for displacing Holocene materials. Dating of the uplifted sand formation indicates an age of 10,081 ± 933 years, the liquefaction features ranging from this age to 3490 ± 473 years BP. This paleoearthquake was of much greater magnitude than those known historically. Faults with neotectonic activity are significant features that should be borne in mind when assessing the seismic hazards of the Canary Islands, presently considered as low and mainly of volcanic origin.

A serologic study of human toxocariasis in the Canary Islands (Spain): environmental influences.

The presence of anti-Toxocara antibodies in the human population of the Canarian Archipelago was studied by means of an indirect enzyme-linked immunosorbent assay with excretory/secretory antigen of infective-stage larva. A total of 14,074 were analyzed, resulting in the following distribution and prevalence by location: southern Tenerife 6,435 (2.5% positive), northern Tenerife 1,710 (6.7% positive), La Palma 1,214 (4.5% positive), La Gomera 264 (6.8% positive), El Hierro 204 (3.9% positive), Gran Canaria 2,875 (2.3% positive). Fuerteventura 277 (1.8% positive), and Lanzarote 1,095 (2.9% positive). The weighted average of the entire Archipelago was 3.4% positive. Neither age nor sex was found to be significantly associated with positive serology. The influence of the different Canarian mesoclimates on the spreading of this zoonosis is demonstrated, with significant differences being found between humid and arid islands. Likewise, a significant positive correlation was found between De Martonne's humidity-aridity index and percentage of people with evidence of parasite exposure on the different islands.

Caracterización morfoscópica de los materiales piroclásticos sálicos del sur de Tenerife (Islas Canarias)

In this work, several morphological aspects of volcanic ash grains from southern Tenerife are studied by S.E.M. Important variations in vesiculation, fracture and wheathering of pyroclasts are observed. It's possible to characterize diferent types of deposits (pyroclastic falIs, pyroclastic flow, surges, etc.) in function of the pumice fragments surface.

The Granadilla pumice deposit of Southern Tenerife, Canary Islands

The Granadilla pumice, the product of a large Plinian eruption, covers over 800 km2 of southern Tenerife. It is, for the most part, reversely graded, and is divided into four fall-units which characterise specific phases in the eruption. Isopach and isograde maps indicate a north-westerly palaeo-wind direction. The results of the granulometric analysis of 170 samples are presented, together with criteria which allow pyroclastic-fall and pyroclastic-flow deposits to be differentiated. The Granadilla eruption took place over 32,000 years B.P. after a considerable repose period. It began with intermittent pumice showers and increased to a continuous high intensity gas blast. Reduced activity during the early part of the eruption allowed rain-flush beds to form while the volcano was quietly venting large volumes of fine ash. The eruption concluded with a pyroclastic-flow which is absent higher on the volcano, having failed to adhere to the steep slopes. The deposits are composed of pumice lapilli, lithic fragments, and a small proportion of sanidine crystals. Each component shows better sorting characteristics than complete samples, the frequency curves of which are asymmetrically skewed by the admixture of varying percentages of lithic fragments. In the finer grades, high lithic percentages are the result of wind drift removing the fine-grained pumice from the eruption cloud. The Granadilla pumice and associated pyroclastic deposits originated in the caldera of Las Canadas to the north-east. The formation of this caldera cannot be explained simply by northward Iandslipping as has been suggested previously. The southward dispersal of many large volume ignimbrites undermines the theory for the formation of Las Canadas by simple landslipping, while the total volume of all pyroclastic deposits in southern Tenerife fully accounts for the volume of the caldera and the pre-Teide volcano. It is therefore believed the formation of the caldera was gradual, in response to the progressive emptying of the magma chamber during a series of largescale Plinian eruptions.