Search

The planktonic dinoflagellate Prorocentrum compressum is widespread in warm and temperate seas. A strain identified as P. cf. compressum BEA 0681B isolated from the island of Gran Canaria, NE Atlantic Ocean, showed a divergence in rDNA/ITS phylogenies with respect to P. compressum. The Canarian strain was oval, with an average length-to-width ratio of 1.35, smooth thecal surface with less than 150 thecal pores, including oblique pores, sometimes with a bifurcated opening. In contrast, P. compressum was rounder, with a length-to-width ratio < 1.2, with reticulate-foveate ornamentation and 200-300 pores per valve. We propose Prorocentrum canariense sp. nov. These species clustered as the most early-branching lineage in the clade Prorocentrum sensu stricto. Although this clade mainly contains planktonic species, the closer relatives were the benthic species P. tsawwassenense and P. elegans. Interestingly, P. compressum and P. canariense sp. nov. are widely distributed in temperate and warm seas without an apparent morphological adaptation to planktonic life. The formation of two concentric hyaline mucilaginous walls could contribute to this success. We discuss the use of Prorocentrum bidens to solve the nomenclature issue of P. compressum that was described citing a diatom as basionym., (© 2024 International Society of Protistologists.)

Extensive offshore meadows of Halimeda incrassata are documented for the first time in sandy bottoms of La Palma, Canary Islands. Halimeda incrassata forms dense sublittoral assemblages between 20 and 55 m, but isolated populations occur down to 65 m depth. This species currently spreads over an area of 9.14 ha. Population coverage varies with depth, with the highest values at 35- 40 m and an average cover of 62.34%. The calcified segments of H. incrassata act as a stable substratum in these soft bottoms for the growth of other macroalgae, such as the rhodophytes Lophocladia trichoclados and Cottoniella filamentosa. Specimens reach lengths of up to 10 cm, shorter than individuals from the Caribbean. Although it is difficult to ascertain whether this species is a recent introduction, there is evidence of a correlation between the increase in population coverage and recent ocean warming, constituting another example of the tropicalization of the marine flora of this region. [ABSTRACT FROM AUTHOR]

Remains of an adult specimen of the poorly known oceanic cephalopod, Taningia danae Joubin, 1931 were found floating in the south-western waters of Tenerife. Here we report for the first time an adult stage of the species in the Canary Islands. The remains, with a total weight of 21.169 kg, presumably belonged to a large adult female given the presence of spermatangia implanted intramuscularly in the ventral side of the mantle. This study confirms the presence of all life stages of the species in the Canary Islands. [ABSTRACT FROM AUTHOR]

Intertidal mollusks are subjected to an intense environmental pressure, from human-induced stressors, mainly harvesting, to competition for food and space with other species. Here we used mollusk shell size as a measure of size distribution and reproductive potential of intertidal limpets. Two species of exploited limpets ( Patella candei crenata and Patella aspera ) were monitored throughout the littoral of Tenerife (Canary Islands, NE Atlantic Ocean), an overpopulated island with a high coastal pressure. The exploitation of these two limpet species is controlled by regional legislation, with seasonal closures and limits of harvest for professional (10 kg) and recreational harvesters (3–5 kg). A long-term comparison (1994–2014) of limpet size has been conducted as a surrogate of the state of conservation of these two limpets. Both species showed populations dominated largely by small-sized individuals (<30 mm) and a lack of large adults (>60 mm). The proximity to coastal settlements was not a factor to explain limpet assemblage structure. The temporal (1994–2014) comparative study showed a sharp decrease in the mean size of both limpet species (7 mm in P . aspera and 5 mm in P . candei crenata ). These results might be indicative of overharvesting of both species in Tenerife. The conservation of the two studied species needs to be accomplished by the strict fulfillment of current protective strategies, as well as the creation of marine protected areas where intertidal harvesting is totally banned all over the year. [ABSTRACT FROM AUTHOR]

Many species have experienced recent range expansions due to human-mediated processes, such as the unintentional transport on ships or plastic waste and ocean warming, which facilitates many tropical species to tolerate living beyond their normal limit of distribution, with a potential impact on autochthonous assemblages. In September 2008, three colonies of the fire coral Millepora sp. (Cnidaria: Hydrozoa) were found on the southeastern coast of Tenerife (Canary Islands), though this species had been previously described to have a circumtropical distribution with Cape Verde Islands as its northern limit of distribution in the eastern Atlantic. The aim of this study was to determine the origin of these new colonies in the Canary Islands (11°N of its previously known northernmost limit of distribution) using variation in the cytochrome oxidase subunit I (COI) gene as a molecular marker. In order to do that, Millepora samples from Tenerife and Cape Verde Islands were collected for molecular analyses, and COI sequences from Caribbean samples listed in GenBank were also included in the analysis. Our results showed that all the specimens from Tenerife were genetically identical, suggesting that the colonization of the Canary Islands was the result of a very recent and strong founder effect. The nucleotide sequences of the samples from the Cape Verde and the Canary Islands were closer to the Caribbean than between themselves, pointing to the Caribbean population as the source population for both archipelagos, through independent founder events. The fact that Millepora sp. arrived to Cape Verde long before arriving to the Canaries (pleistocene fossils have been found in that archipelago) suggests that the habitat requirements for this species did not exist before in the Canarian archipelago. Therefore, the rising seawater temperatures recently registered in the Canary Islands could have facilitated the settlement of reef-forming corals drifting across the two basins of the Atlantic. [ABSTRACT FROM AUTHOR]

This work investigated the biology of Chaceon affinis in two isolated populations of the Atlantic Ocean, including depth distribution, sexual structure, reproductive patterns and intermoult period. Males were larger and heavier than females. Mean size decreased with depth for both males and females. The highest abundance was found at 600–799 m of depth for males and at 800–999 m depth stratum for females. The highest abundance of ovigerous females was found at the 800–999 m depth stratum. Of the different ovaries’ colour or colour shades recorded, only six categories were histologically characterized. The presence of spermatophores in the spermatheca of females in carapace stages II and III suggests that spermatophores are viable and used during the intermoult period. The size at sexual maturity in females was estimated at 104.4–104.7 mm carapace width (CW) in Madeira, and 109.3–110.5 mm CW in the Canary Islands. Only three categories of testes were identified. Mature testes consisted in a large mass, with highly coiled vasa deferentia visible to the naked eye. The size at sexual maturity in males was estimated at 113.8 mm CW in Madeira and 118.9 mm CW in the Canaries. The relative growth of males showed significant changes along the ontogeny and size at which allometric growth changes, as an indicator of morphometric maturity, occurred between 103.2 and 103.6 mm CW in Madeira and between 111.4 and 113.1 mm CW in the Canaries. In females, size at which allometric growth changes was found for maximum width of fifth abdominal somite (AS5W) at 98.2 mm CW in Madeira and 103.0 mm CW in the Canaries. The size at maturity obtained for C. affinis indicates that the minimum landing size (MLS) should not be set smaller than 125 mm CW in Madeira and 130 mm CW in the Canaries. This conservative MLS, higher than length at functional maturity, would safeguard immature individuals until they reach the size at which they can contribute to the reproductive capacity of the population. Ovigerous females were observed from October to April in Madeira, and in all months in the Canaries. Moreover, the observation of berried females in the last developmental stage in all quarters of the year suggests that gonad maturation and release of larvae are asynchronous throughout the spawning season. A total of 138 crabs with CW between 96 and 154 mm were tagged off Madeira. Of these, nine were recovered in the same area, more than 900 days after tagging. Eight of the recaptures were females with a wide range of CW confirming intermoult periods exceeding three years with expected growth per moult of less than 20 mm CW. [ABSTRACT FROM AUTHOR]

Species of the dinoflagellate genus Gambierdiscus are the cause of Ciguatera Fish Poisoning, common in tropical areas. Nevertheless, until recently this syndrome was not reported in the NE Atlantic Ocean. A new photosynthetic dinoflagellate species, Gambierdiscus silvae sp. nov. is described based on samples taken from tide pools on rocky shores of the Canary Islands (NE Atlantic Ocean). Its morphology was studied by light and scanning electron microscopy. The new species is anterioposteriorly compressed, lenticular in shape with an epitheca slightly higher than the hypotheca. It is round in apical view and has a thick smooth theca with many scattered pores. Plate formula is Po, 4′, 0a, 6″, 6c, 6s?, 5′″, 0p, 2″″. Plate 2′ is hatchet-shaped and Plate 2″″ is very wide and the largest of the hypotheca. Phylogenies inferred from the large subunit nuclear rRNA showed that three G. silvae strains clustered in a well supported sister clade to G. polynesiensis , distinct from the other species. G. australes was observed for the first time in the Atlantic, together with G. excentricus already reported from these islands. This work increases the number of Gambierdiscus species described and shows their unexpected diversity in the Canary Islands. [ABSTRACT FROM AUTHOR]

The island of Fuerteventura, a UNESCO Biosphere Reserve in the Atlantic Ocean, aims to develop renewable energy sources, in particular wave and offshore wind energy, to reduce its carbon footprint. In this context, the objectives of this work are: (i) to assess the wave and offshore wind resources around the island; and (ii) to determine the area or areas that are best suited for their exploitation, taking into account the resource assessment and other conditioning factors such as the bathymetry, distance to the coastline and ports, and offshore zoning prescribed by the authorities. To accomplish these objectives, hindcast wave and wind data obtained with numerical models are used alongside observations from meteorological stations. We identify two areas as having great potential for offshore wind farms; one of them is also very promising for a combined wave-wind farm (or a wave farm on its own). We characterise in detail the wind resource in both areas, and the wave resource in the latter: the wind resource, in terms of directions and velocities; and the wave resource, in terms of directions, significant wave heights and energy periods. In the case of the wind resource, most of the energy corresponds to NNE and NE winds with velocities between 8 and 14ms-1, which should be taken into account when selecting the offshore wind turbines. As for the wave resource, we find that most of the annual wave energy is provided by N and NNW waves with significant wave heights between 1.5m and 3.0m and energy periods between 10.5s and 13.5s. It follows that the Wave Energy Converters deployed in the area should have maximum efficiency in those ranges. In sum, Fuerteventura has a substantial wave and offshore wind resource, which is assessed in this work; two areas for their exploitation are proposed, and the ranges of wave and wind conditions for which the wave energy converters and offshore wind turbines to be installed should have maximum efficiency are determined. [ABSTRACT FROM AUTHOR]

Lack of knowledge of the marine realm may bias our perception of the current status and threats to marine biodiversity. Less than 10% of all ecological literature is related to the ocean, and the information we have on marine species that are threatened or on the verge of extinction is scarce. This lack of information is particularly critical for isolated areas such as oceanic archipelagos. Here we review published and grey literature on the current status of marine organisms in the Canary Islands as a case description of the consequences that current out-of-sight out-of-mind attitudes may have on this unique environment. Global change, as represented by coastal development, pollution, exotic species and climate change, are currently affecting the distribution and abundance of Canarian marine organisms, and pose multiple threats to local species and communities. Environmental risks are significant at community and species levels, particularly for threatened species. Failure to address these trends will result in shifts in local biodiversity with important ecological, social, and economic consequences. Scientists, policy makers, educators, and relevant societal groups need to collaborate to reverse deleterious coastal biodiversity trends. [ABSTRACT FROM AUTHOR]

The concentrations of 18 polychlorinated biphenyls (PCBs), 23 organochlorine pesticides (OCPs), and 16 polycyclic aromatic hydrocarbons (PAHs) were determined in the blubber and liver of 27 bottlenose dolphins ( Tursiops truncatus ) stranded along the Canary Islands coasts from 1997 to 2011. DDTs (mean of 60,960 and 445 ng/g lw., respectively) and PCBs (mean of 47,168 and 628 ng/g lw., respectively) were the predominant compounds in both tissues. Among PCBs the highly chlorinated PCB 180, 153 and 138 were the predominant congeners. We found a p , p ′-DDE/∑DDTs ratio of 0.87 in blubber and 0.88 in liver, which is indicative of DDT ageing. All the samples showed detectable values of any of the 16 PAH studied. Phenanthrene was the most frequently detected and at the highest concentration. According to our results, concentrations of OCPs, and especially PCBs, are still at toxicologically relevant levels in blubber of bottlenose dolphins of this geographical area. [ABSTRACT FROM AUTHOR]

The Canary Island Seamount Province forms a scattered hotspot track on the Atlantic ocean floor ~1300 km long and ~350 km wide, perpendicular to lithospheric fractures, and parallel to theNWAfrican continental margin. New 40Ar/39Ar datings show that seamount ages vary from 133 Ma to 0.2 Ma in the central archipelago, and from 142 Ma to 91 Ma in the southwest. Combining 40Ar/39Ar ages with plate tectonic reconstructions, I find that the temporal and spatial distribution of seamounts is irreconcilable with a deep fixed mantle plume origin, or derivation from passive mantle upwelling beneath a mid-ocean ridge. I conclude that shallow mantle upwelling beneath the Atlantic Ocean basin off the NW African continental lithosphere flanks produced recurrent melting anomalies and seamounts from the Late Jurassic to Recent, nominating the Canary Island Seamount Province as oldest hotspot track in the Atlantic Ocean, and most long-lived preserved on earth. [ABSTRACT FROM AUTHOR]

Abstract: Lanzarote (Canary Islands, Spain) is a UNESCO Biosphere Reserve (since 1993) located in the Atlantic Ocean. The island is aiming to change its energy production model in order to reduce its dependence on external, fossil-fuel-based energy sources. The local authorities hope to develop an energy production model based on clean, renewable sources, such as wave energy converters (WECs). This study analyses the island''s wave energy resources using a 51-year series of data obtained from numerical modelling (hindcast and forecast). The spatial distribution of wave power is analysed using data from nine points around the island. Significant resources (average wave power exceeding 30 kW/m and average annual wave energy of more than 270 MW h/m) are found to the north of the island, as well as to the west and the east (average wave power 25–30 kW/m). Considerable seasonal variability is found, with winters being rather high-energetic and summers quite mild. Variability coefficients are computed in order to select the best locations for WECs; the composition of the resource at each location is examined in terms of sea states in order to evaluate the suitability of WEC installation. Finally, three sites with similar conditions, all located on the north side of the island, are selected as the best candidates for WEC deployment. [Copyright &y& Elsevier]

The otolith was used to investigate the variability between Aphanopus carbo and Aphanopus intermedius inhabiting the north-eastern Atlantic Ocean. The results indicate a high degree of morphological affinity between species and areas; a noticeable metabolic change in the otolith shape was noted in the specimens of A. carbo, which may be related to migrations of individuals from shallow water (closer to the continental coast) to deeper water (archipelagos of Madeira and the Canary Islands). The results suggest a single population for both species in the north-eastern Atlantic Ocean, although not conclusively. [ABSTRACT FROM AUTHOR]

The article discusses a study on song characterization in Sylvia conspicillata, a perching bird found in Fuerteventura, Canary Islands in the Atlantic Ocean. The study says that bird songs help in studying the speciation processes and also help in characterizing the divergent characters among the population. The study reveals that the spectacled warbler consists of a complex repertoire for creating new song elements and lack of geographical barriers help in spreading the song freely.

We performed morphological and molecular studies of Laurencia catarinensis from the Canary Islands. This species has an entangled habit, cushion-like tuft formation, cortical cell walls, slightly to markedly projecting near the apex, and lacking lenticular thickenings in medullary cells. We inferred its phylogenetic position by analyzing the chloroplast-encoded rbc L gene sequences from 41 samples. The results demonstrate that specimens of L. catarinensis from the Canary Islands, where it is referred to as L. intricata, and those from Brazil (including specimens from the type locality in Santa Catarina) form a monophyletic clade with low genetic divergence (0-0.9%). In contrast, specimens of L. intricata from the type locality in Cuba, Mexico, and the USA were clearly distinct from L. catarinensis collected in Brazil and the Canary Islands, as shown by high genetic divergence values (4.9-5.7%). The type material of L. catarinensis from Brazil allowed us to identify all samples from the Canarian Archipelago as L. catarinensis. These findings expand the known geographical distribution of L. catarinensis to the eastern Atlantic Ocean and demonstrate an amphi-Atlantic distribution of the species. [ABSTRACT FROM AUTHOR]

Abstract: The present work analysed the main changes in subtidal algal assemblages in the last decade in an oceanic archipelago (Canary Islands – eastern Atlantic Ocean). Changes result from increases in cover of ephemeral benthic algae, such as the non-native chlorophyte Pseudotetraspora marina and the native cyanophytes Blennothrix lyngbyacea, Schizothrix calcicola and Schizothrix mexicana. Ephemeral algae overgrow subtidal assemblages which are extensively dominated by Lobophora variegata, but competitively do not exclude other species. Increases in the abundance of species coincided with a warming of about 2 °C in surface seawater temperature (SST) linked to the weakening of the Cold Canary Current and the Northwestern African upwelling. Shifts in the distribution and cover of ephemeral species follow the SST gradient from warmer waters in the western islands to colder waters in the eastern ones. While in the warmest western islands, species have spread quickly colonizing all type of substrates in just a few years (2005–2008), the occurrence of ephemerals towards the coldest eastern islands is yet inconspicuous. [Copyright &y& Elsevier]

The genus Osmundea is a strongly supported monophyletic group within the Laurencia complex and shows a disjunct distribution occurring in the North-East and South-West Pacific, the Indian and Atlantic oceans and the Mediterranean Sea. Its phenotypic plasticity on the Canary Islands may be the result of the high ecological variability partially due to the particular oceanographic characteristics in this region. The combination of molecular analyses based on the comparison of the chloroplast-encoded rbcL sequences and morphological data allowed us to delimit three distinct taxa from the coasts of the Canarian Archipelago: Osmundea pinnatifida, Osmundea truncata and an unidentified species, Osmundea sp. Moreover, the high value of genetic divergence between Osmundea sp. and the rest of the Osmundea species suggests that this taxon should be assigned to a new species within the Osmundea genus. Occurrence of O. hybrida and O. oederi (synonym: O. ramosissima) has not been confirmed. Our results also suggest a possibly questionable record of the taxa O. hybrida and O. oederi on the Canary Islands. [ABSTRACT FROM AUTHOR]

Abstract: Cetacean morbillivirus (CeMV) is considered the most pathogenic virus in cetaceans. Three strains have been already described: the dolphin morbillivirus (DMV), the porpoise morbillivirus (PMV) and the tentatively named pilot whale morbillivirus (PWMV). This study describes the molecular characterization of a strain of CeMV detected in the brain of a short-finned pilot whale that had stranded in the Eastern Atlantic Ocean around the Canary Islands and that showed lesions compatible with morbilliviral disease. Sequences for the nucleoprotein, phosphoprotein, fusion protein and haemagglutinin genes were obtained. The phylogenetic study showed high homology (97%) with the PWMV strain previously detected from a long-finned pilot whale stranded in the Western Atlantic Ocean. These results support the existing classification of CeMV into three principal genetic clusters. [Copyright &y& Elsevier]

Abstract: The island of El Hierro (Spain), a UNESCO Biosphere Reserve in the Atlantic Ocean, aims to become the first 100% renewable energy island in the world. With a €54 million wind project already under way, the present research looks at the island’s wave resource using a 44-year hindcast dataset obtained through numerical modelling. The geographical distribution of wave energy is examined on the basis of eight study sites around the island. A substantial resource is found west and north of El Hierro, with average wave power in the order of 25 kW m−1 and total annual energy in excess 200 MW h m−1; the resource is less abundant east and south of the island. In addition to these geographical variations, wave energy in El Hierro presents seasonal variations, with energetic winters and mild summers. After analysing the total resource and its spatial and seasonal variations, its composition in terms of sea states (significant wave heights and energy periods) is examined, and how this composition affects the selection of the Wave Energy Converters to be installed is discussed. [ABSTRACT FROM AUTHOR]

Following a series of surveys with bottom longlines and fish traps along the island slopes off the archipelagos of Madeira, Canaries and Cape Verde, and with bottom trawls along the coast of Morocco and Western Sahara between 2004 and 2006 many specimens of Synaphobranchus were caught, revealing the presence of two species. Based on these specimens and Museum preserved specimens from this area grey cutthroat, Synaphobranchus affinis Gunther, 1877, is recorded for the first time from off Portugal, Madeira archipelago, Great Meteor Seamount, Canary Islands, Morocco, Western Sahara, Cape Verde Islands, and Senegal. It is confirmed that S. kaupii is also conspecific in this area. Meristic and morphometric data of the specimens studied are also presented. [ABSTRACT FROM AUTHOR]

The fossil and subfossil mammal scenario of the oceanic islands of Macaronesia - the Azores, Madeira, and the Savage Islands (Portugal), the Canary Islands (Spain) and Cape Verde - is disconcertingly scant, consisting almost exclusively of the same taxonomic groups characterised by a homogeneous composition of species. The very few endemites can be referred essentially to three species of chiroptera in addition to three murids, which became extinct on the Canaries in historical times, and one representative of the taxonomic group of the Soricomorpha, the Canarian shrew, Crocidura canariensis Hutterer, Lopez-Hurado and Vogle 1987. It is the sole non-volant mammal still dispersed on the Canary Islands, where its occurrence is reported from Fuerteventura, La Graciosa, Lanzarote, and possibly from the two islets of Lobos and Montaña Clara. Owing to its vicinity to continental Africa, the Canary archipelago is the only one in the Eastern Atlantic islands to have been characterised by a non-volant mammalian fauna, whereas such elements do not appear to have been diffused in either the Azores or Cape Verde throughout the entire recent Quaternary. The current mammalian composition of these islands is characterised by the presence of species of almost entirely continental and anthropochorous origin. Evidence shows that the extant occurrence of non-volant mammals appears to be almost exclusively a result of human introduction during the late Holocene. The timing of such processes and the biological success of certain introductions (i.e., naturalisation) raise questions about the proper use of terms such as 'natural' or 'artificial' when dealing with expansions of anthropochorous range. [ABSTRACT FROM AUTHOR]

Palisada flagellifera (Ceramiales, Rhodophyta) is recorded for the first time in the eastern Atlantic Ocean off Tenerife, La Gomera, La Palma and Fuerteventura, Canary Islands, Spain. The specimens were collected in 2006–2009 growing from the lower intertidal to subtidal zones to 2 m depth at sites exposed to wave action. The species possesses a palisade-like arrangement of cortical cells in cross section, lacks secondary pit connections between them, and has tetrasporangia produced by three fertile pericentral cells (the third and the fourth additional and the second that becomes fertile), and a right-angled arrangement of tetrasporangia. Gametangia were not observed. The phylogenetic relationships were inferred by analyses of the chloroplast-encoded rbcL gene sequences from 46 taxa. The Canarian and Brazilian P. flagellifera specimens formed a highly supported clade with a low level of genetic variation in the rbcL sequences (0.02–0.04%), confirming that they are the same taxonomic entity. This study expands the geographical distribution of P. flagellifera to the eastern Atlantic Ocean. [ABSTRACT FROM AUTHOR]

Abstract: We compared in-situ and satellite-derived measures of the biological carbon pump efficiency at the two seemingly similar subtropical North Atlantic gyre time series sites, the Bermuda time series (BATS, Bermuda Atlantic time-series study and OFP, ocean flux program) in the western gyre and the ESTOC time series (European station for time-series in the ocean, Canary Islands) in the eastern gyre. Satellite-derived surface chlorophyll a was slightly lower at Bermuda compared to ESTOC (annual average of 0.10±0.04 vs. 0.14±0.05-mg-m−3), as was satellite-derived primary production (annual average of 380±77 vs. 440±80-mgC-m−2 d−1). However, export production normalized to primary production (export ratio) was higher at Bermuda by a factor of 2–3 when estimated using mesopelagic traps moored at 500-m depth and by a factor of 3–4 when estimated using surface-tethered drifting traps. When averaged seasonally, flux at BATS was highest in spring (March, April, May) at all depths followed by summer (June, July, August) and decreasing towards fall, but this seasonality was less visible at ESTOC. Seasonal comparison showed the fastest flux attenuation at Bermuda in winter and spring, coinciding with the highest POC flux. POC/PIC ratios derived from the moored traps were significantly higher at BATS than at ESTOC in fall and winter, but this difference was not significant in spring (p>0.05). This study shows that while the western and eastern Atlantic subtropical gyres have similar rates of primary production, the biological carbon pump differs between the two provinces. Higher new nutrient input observed at Bermuda compared to ESTOC might explain part of the difference in export ratio but alone is insufficient. Greater winter mixed-layer depths and higher mesoscale eddy activity at Bermuda resulting in pulsed production events of labile organic matter might explain both the higher export flux and export ratios found at Bermuda. [Copyright &y& Elsevier]

Abstract: We present hafnium (Hf) and neodymium (Nd) isotopic compositions and concentrations in surface waters of the eastern Atlantic Ocean between the coast of Spain and South-Africa. These data are complemented by Hf and Nd isotopic and concentration data, as well as rare earth element (REE) concentrations, in Saharan dust. Hafnium concentrations range between a maximum of 0.52pmol/kg in the area of the Canary Islands and a minimum value of 0.08pmol/kg in the southern Angola Basin. Neodymium concentrations also show a local maximum in the area of the Canary Islands (26pmol/kg) but are even higher between ∼20°N and ∼4°N reaching maximum concentrations of 35pmol/kg. These elevated concentrations provide evidence of inputs from weathering of the Canary Islands and from the partial dissolution of dust from the Sahara/Sahel region. The inputs from ocean island weathering are also reflected in radiogenic Hf and Nd isotopes. The Hf isotopic compositions of dust samples themselves are highly variable, ranging between ε Hf =−20 and −0.6. The combined Hf and Nd isotopic compositions of dust plot close to the “terrestrial array” during periods of appreciable dust load in the atmosphere. During low atmospheric dust loading combined Hf and Nd isotopic compositions similar to seawater are observed. Most of the variability can be explained in terms of variable degrees of zircon loss from the dust samples, which in turn is linked to sorting during atmospheric transport to the eastern Atlantic Ocean and possibly presorting by sedimentary redistribution on the continent. In addition, increasing relative proportions of radiogenic clay minerals with decreasing grain size may contribute to the radiogenic Hf isotopic compositions observed. While the Nd isotopic composition in the surface ocean reflects the Nd isotopic composition of the Saharan dust adjacent to the Sahara/Sahel region, the release of Hf from that dust appears to be incongruent and results in surface ocean Hf isotopic compositions which are ∼10 ε Hf more radiogenic than the bulk dust. Radiogenic Hf appears to be released from clays and possibly from trace apatite. Rare earth element patterns of dust samples indicate the presence of apatite but provide no evidence for ferromanganese grain coatings, suggesting that such coatings are insignificant in the release of Hf and Nd from Saharan dust to the surface ocean. The Nd isotopic composition of the surface waters becomes less radiogenic south of the equator, most likely reflecting the release of Nd from Congo river sediments. The release of Hf from Saharan dust and the Congo river sediments, however, does not produce distinct Hf isotopic signatures in the surface ocean, implying that the mobile fraction of Hf integrated over large continental areas is isotopically uniform. The Hf isotopic uniformity in the surface ocean means that the limited variability in deep water isotopic compositions is consistent with a short deep water residence time and reflects homogenous continental inputs rather than efficient deep water homogenization. [Copyright &y& Elsevier]

Cryptic speciation is repeatedly reported in sponge taxonomic studies. Most of the cryptic species, which were revealed by molecular markers, have never been formally described owing to the difficulty in finding diagnostic phenotypic characters. A previous molecular study revealed four genetically distinct species that had been misidentified as Scopalina lophyropodaSchmidt. One species was S. lophyropoda sensu stricto, whereas the other three were new species. Here, the three new species are formally described after careful searching for discriminatory phenotypic characters. The new species are Scopalina blanensis, sp. nov. from the north-western Mediterranean, S. ceutensis, sp. nov. from the Mediterranean coasts of Africa (Atlantic waters) and S. canariensis, sp. nov. from the Canary Islands, Atlantic Ocean. All of them are at first sight morphologically similar and inhabit shallow environments with resuspended sediment. However, a closer examination allowed us to find some differential features: e.g. the amount of spongin embedding the spicules, the degree of complexity of the skeletal tracts, the size and curvature of the styles, the growth habit and the colour tinge. Furthermore, an identification key to the Atlanto-Mediterranean Scopalinaspecies is presented. The differences between the genera Scopalina, Ulosaand Dictyonellaare also discussed. [ABSTRACT FROM AUTHOR]

Abstract: The Cream-coloured Courser Cursorius cursor is a poorly known species inhabiting arid environments of the Western Palaearctic. The easternmost main islands of the Canary archipelago (Fuerteventura and Lanzarote, North Atlantic Ocean, Spain) harbour a stable population. The species showed an intense habitat selection pattern in these islands. Its probability of occurrence was highest in locations of relatively flat terrain (maximum slope steepness <11%), below 197m a.s.l., with scarce shrub cover less than 16%, and a rock cover less than 23%. Roads were the only human disturbance among those considered in the study (i.e., dirt tracks, urban developments, agriculture), having a clear negative effect on the occurrence of the Cream-coloured Courser. This paper highlights the importance of an issue deserving greater attention in future studies: fine-grained habitat features, which are not directly related to vegetation structure, but are relative to topographic and lithological traits, largely determine habitat selection of birds inhabiting arid environments. [Copyright &y& Elsevier]

Abstract: We investigated spatio-temporal variability in the abundances and biomasses of four species of inshore serranids (the dusky grouper Ephinephelus marginatus, the island grouper Mycteroperca fusca, the painted comber Serranus scriba, and the blacktail comber S. atricauda) throughout the Canarian Archipelago (central-east Atlantic Ocean) with underwater visual transects. By means of a multiscaled sampling design spanning three orders of magnitude of spatial variability (from 10s of meters among replicated 100m2 transects to 100s of kilometres among islands) and four sampling periods, we related differences in the distributions of serranids to differences in the degree of human pressure, such as fishing intensity and human population. Differences in human pressure among islands provide the most parsimonious explanation for many of the consistent inter-island differences in the abundance and biomass of the analyzed species. Larger-bodied serranids (E. marginatus and M. fusca) are more vulnerable than the smaller species (S. scriba and S. atricauda). In fact, the larger, more vulnerable species have been almost completely extirpated from the most intensely fished islands. Our results show that the larger groupers have been overexploited throughout the Canary Islands, and highlight the urgent need for stringent management measures and better control of littoral reef fish resources. [Copyright &y& Elsevier]

Abstract: We investigated spatio-temporal variability in the population structure of the parrotfish, Sparisoma cretense (Linnaeus, 1758), throughout the Canarian Archipelago (eastern Atlantic Ocean) with underwater visual transects. By means of a multiscaled hierarchical sampling design spanning three orders of magnitude of spatial variability (from 10s of meters between replicated 100m2 transects to 100s of kilometres among islands) and four sampling times (twice a year in 2003 and 2004); we related differences between islands to differences in the degree of fishing pressure. The mean abundance of parrotfish across all counts was 6.79±0.46 ind 100m−2 (mean±S.E., n =768 transects), while the mean biomass was 593.81±45.61g 100m−2 (mean±S.E., n =768). Abundances and biomasses of S. cretense clearly differed between islands, although they were relatively consistent between the sampling times. The different abundances and biomasses observed between islands were correlated with fishing pressure, providing evidence that fishing was responsible for the inter-island differences. Differences in the size-structure between the eastern and western islands suggest differences in the recruitment periodicity at both groups of islands, which could be related to large-scale spatial variation in the oceanographic conditions across an east–west gradient along the Canary Islands. [Copyright &y& Elsevier]

Provides information about the age and growth of the blacktail comber Serranus atricauda Gunther, 1974 from the Canary Islands, eastern-central Atlantic. Description of length-weight relationship; Determination of age from annuli in whole otoliths; Growth parameters.

The article presents a study that explores the levels of polychlorinated biphenyls (PCB) congeners including the coplanar ones in the liver of six shark species collected around the Canary Islands in the North African Atlantic Ocean and to correlate these with their sex, age, size, habitat and diet. The shark samples were collected in the surroundings of the Canary Islands between July 93 and September 94, during spring and summer seasons when the islands were not an industrialized area and only moderately populated, with a petrol refinery located on one of the islands as a possible PCB emission source.

Laurencia caduciramulosa is recorded for the first time for the eastern Atlantic Ocean off Tenerife, Canary Islands, Spain. The specimens were collected in 2006, growing epilithically in the lower intertidal zone on moderately exposed rocky shores. This species is characterized by reduced size, a well-developed stolon-like basal system and erect axes with abundant deciduous branchlets that function as propagules, except on the uppermost portions of the branches, where they form crowns of branchlets. As in all other reports of this species, gametangia and sporangia were not observed. This study expands the geographical distribution of L. caduciramulosa to the eastern Atlantic Ocean. [ABSTRACT FROM AUTHOR]

In the last decade, several outbreaks of ciguatera fish poisoning (CFP) have been reported in the Canary Islands (central northeast Atlantic Ocean), confirming ciguatera as an emerging alimentary risk in this region. Five Gambierdiscus species, G. australes , G. excentricus , G. silvae , G. carolinianus and G. caribaeus , have been detected in macrophytes from this area and are known to produce the ciguatoxins (CTXs) that cause CFP. A characterization of the toxicity of these species is the first step in identifying locations in the Canary Islands at risk of CFP. Therefore, in this study the toxicity of 63 strains of these five Gambierdiscus species were analysed using the erythrocyte lysis assay to evaluate their maitotoxin (MTX) content. In addition, 20 of the strains were also analysed in a neuroblastoma Neuro-2a (N2a) cytotoxicity assay to determine their CTX-like toxicity. The results allowed the different species to be grouped according to their ratios of CTX-like and MTX-like toxicity. MTX-like toxicity was especially high in G. excentricus and G. australes but much lower in the other species and lowest in G. silvae . CTX-like toxicity was highest in G. excentricus , which produced the toxin in amounts ranging between 128.2 ± 25.68 and 510.6 ± 134.2 fg CTX1B equivalents (eq) cell -1 (mean ± SD). In the other species, CTX concentrations were as follows: G. carolinianus (100.84 ± 18.05 fg CTX1B eq cell -1 ), G. australes (31.1 ± 0.56 to 107.16 ± 21.88 fg CTX1B eq cell -1 ), G. silvae (12.19 ± 0.62 to 76.79 ± 4.97 fg CTX1B eq cell -1 ) and G. caribaeus ( -1 ). Unlike the similar CTX-like toxicity of G. australes and G. silvae strains from different locations, G. excentricus and G. caribaeus differed considerably according to the origin of the strain. These differences emphasise the importance of species identification to assess the regional risk of CFP.

The contents of 3 heavy metals (Al, Cd, and Pb) and 10 trace elements (B, Cr, Cu, Fe, Li, Mg, Ni, Sr, V, Zn) were determined by means of atomic emission spectrometry with inductively coupled plasma (ICP-OES) in 117 specimens of red mullet, Mullus surmuletus. The specimens were taken in two of the Canary Islands; two locations on the island of Tenerife: Candelaria on the northeast coast and Punta de Hidalgo on the north coast and Arguineguín, on the south coast of the island of Gran Canaria. No significant differences were found between the two sites in Tenerife regarding the metal content of the specimens studied, but differences were found between the specimens captured in Arguineguín and the two sites in Tenerife, the latter having higher concentrations of the analyzed metals.

Nowadays, the use of wild and culture harvest seaweed in food industry is a booming productive sector. In this context, a radiological characterization of five globally common seaweed species that were collected in arrival on Gran Canaria coast was carried out. The studied algae species were Cymopolia barbata, Lobophora variegata, Sargassum vulgare, Dictyota dichotoma and Haliptilon virgatum. Radionuclides analysed by alpha and gamma spectrometry were 238 U, 234 U, 235 U, 210 Po, 234 Th, 226 Ra, 210 Pb, 228 Th, 224 Ra, 40 K and 7 Be. Activity concentrations, ratios, and concentration factors (CF) were determined for all samples collected. The CF in algae was higher for reactive-particle radionuclides ( 210 Po, 234 Th, 228 Th and 210 Pb) than for conservative ones ( 40 K and the uranium isotopes). 210 Po, 228 Th and 234 Th CF were one or two orders of magnitude higher than those recommended by the IAEA. L. variegata, C. barbata and S. vulgare showed a clear preference for 210 Pb and 210 Po, for uranium radioisotopes, and for 40 K and 234 Th, respectively. A dosimetry assessment due to seaweed ingestion showed considerable values of annual committed effective dose for H. virgatum (605 ± 19 μSv/y), L. variegata (574 ± 17 μSv/y) and D. dichotoma (540 ± 30 μSv/y). Hence, this study suggests that an algae radiological characterization is recommended as part of the product valorising process., (Copyright © 2018. Published by Elsevier B.V.)

Summary Half a century ago, MacArthur and Wilson proposed that the number of species on islands tends toward a dynamic equilibrium diversity around which species richness fluctuates [ 1 ]. The current prevailing view in island biogeography accepts the fundamentals of MacArthur and Wilson’s theory [ 2 ] but questions whether their prediction of equilibrium can be fulfilled over evolutionary timescales, given the unpredictable and ever-changing nature of island geological and biotic features [ 3–7 ]. Here we conduct a complete molecular phylogenetic survey of the terrestrial bird species from four oceanic archipelagos that make up the diverse Macaronesian bioregion—the Azores, the Canary Islands, Cape Verde, and Madeira [ 8, 9 ]. We estimate the times at which birds colonized and speciated in the four archipelagos, including many previously unsampled endemic and non-endemic taxa and their closest continental relatives. We develop and fit a new multi-archipelago dynamic stochastic model to these data, explicitly incorporating information from 91 taxa, both extant and extinct. Remarkably, we find that all four archipelagos have independently achieved and maintained a dynamic equilibrium over millions of years. Biogeographical rates are homogeneous across archipelagos, except for the Canary Islands, which exhibit higher speciation and colonization. Our finding that the avian communities of the four Macaronesian archipelagos display an equilibrium diversity pattern indicates that a diversity plateau may be rapidly achieved on islands where rates of in situ radiation are low and extinction is high. This study reveals that equilibrium processes may be more prevalent than recently proposed, supporting MacArthur and Wilson’s 50-year-old theory. [ABSTRACT FROM AUTHOR]

Seaweeds are being consumed more often worldwide and are a source of essential minerals, fiber, vitamins, amino acids, and various bioactive compounds that have many beneficial effects on human health. However, marine pollution and the high capacity of seaweed to absorb metals may mean this food can also be dangerous to human health. The concentrations of some trace elements (B, Ba, Fe, Ni, Li, and V) and toxic metals (Al, Cd, and Pb) were determined in various species of wild seaweeds in the Phaeophyta group of brown algae from the Atlantic Ocean. Inductively coupled plasma atomic emission spectrometry revealed high concentrations of Al (256 mg/kg dry weight), Pb (3.92 mg/kg dry weight), and Cd (0.20 mg/kg dry weight) in Padina pavonica. Pb contributed the most to the tolerable daily intake (TDI) of toxic metals in these samples; 57.2 and 45.3% of the TDI for Pb was found in 5 g of dehydrated P. pavonica and Halopteris scoparia, respectively. This percent contribution is half of the recommended TDI for this metal, which is 34.24 μg/day; therefore, high consumption of these species is discouraged. The maximum TDIs established by various institutions for the other metals were not exceeded from the daily consumption of 5 g of the other dehydrated seaweeds evaluated in this study.

The African brown snapper Lutjanus dentatus is a fish native of the West African coastal zone of the Atlantic Ocean. Here we document the first recorded capture of this species in the Canary Islands, an archipelago close to Africa, in August 2013. [ABSTRACT FROM PUBLISHER]

An account of the species of the family Bramidae (Teleostei, Perciformes) from the Canary Islands is given. Pterycombus brama, Taractes asper and Taractes rubescens are recorded for the first time in the Canaries, which brings to six the number of bramid species recorded in the area. Available data on distribution, habitat, and morphometry of the studied species are presented. [ABSTRACT FROM AUTHOR]

The present knowledge of the marine phanerogams of the Canary Islands is poorly documented. Earlier studies of the marine phytobenthos along the Canarian coasts provides little information on seagrass ecosystems and their distributional patterns. This contribution summarizesthe available information about the three species reported for the islands: Cymodocea nodosa (Ucria) Ascherson, Halophila decipiens Ostenfeld and Zostera noltii Hornemann; and their distributional records is analized in relation with the main oceanographic and geomorphological conditions. Cymodocea nodosa and Halophila decipiens are present in shallow subtidal areas on diverse mobile substrata, whereas Zosteranoltii has been reported for intertidal communities in one eastern locality of Lanzarote Island, with historical records in Fuerteventuraand Gran Canaria Islands. At present, the latter species is not found in any of the mentioned localities and probably its has disappeareddue to anthropogenic activities (urban pollution, sediments disturbances). Most of the localities with seagrass communities are located in the eastern and southern coasts of the islands, always in shelteredareas, protected against Trade Winds. The vertical distribution of Cymodocea nodosa meadows ranges from (0.3) 2 to 35 m depth, whereas Halophila decipiens meadows are present between 6 to 40 m depth. [ABSTRACT FROM AUTHOR]