374 research outputs found

    The Canary Islands coastal transition zone – upwelling, eddies and filaments [Editorial]

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    3 pages.-- Printed version published in issue Aug-Sep 2004.-- Issue title: "The Canary Islands Coastal Transition Zone - Upwelling, Eddies and Filaments".Full-text version available Open Access at: http://www.iim.csic.es/~barton/html/pdfs.htmlThe marine science and technology (MAST) III program of the European Union funded the Canary Islands Azores Gibraltar Observations (CANIGO) project from 1996 to 1999 with the overarching objective of a better understanding of the physics, biogeochemistry and paleoceanography of the eastern subtropical North Atlantic. Parrilla et al., 2002 G. Parrilla, S. Neuer, P.Y. Le Traon and E. Fernandez-Suarez, Topical studies in oceanography: Canary Islands Azores Gibraltar Observations (CANIGO) Volume 1: Studies in the northern Canary Islands basin, Deep-Sea Research Part II-Topical Studies In Oceanography 49 (2002) (17), pp. 3409–3413. Article | PDF (73 K) | View Record in Scopus | Cited By in Scopus (12)Parrilla, Neuer, Le Traon, and Fernandez-Suarez (2002) edited two volumes of papers detailing many results of the project. The present compilation of papers complements those volumes by reporting observational work carried out in the last months of the project, too late for inclusion there. The component of CANIGO reported here, which focussed on the transition zone of the NW African coastal upwelling downstream of the Canary Islands, was an interdisciplinary effort involving researchers from ten institutes and universities in Spain, UK and France.This work was supported by the European Union (Project CANIGO, MAS3.CT96-0060).Peer reviewe

    Variability in the Canary Islands area of filament-eddy exchanges

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    24 pages, 17 figures, 1 table.-- Printed version published in issue Aug-Sep 2004.-- Issue title: "The Canary Islands Coastal Transition Zone - Upwelling, Eddies and Filaments".Full-text version available Open Access at: http://www.iim.csic.es/~barton/html/pdfs.htmlThe physical background to a suite of biological studies carried out in the Canary Islands upwelling region is presented. The area is unique in that the coastal transition zone is spanned by an archipelago of islands that shed mesoscale eddies of diameter 50–100 km into the alongshore flow. A recurrent filament and eddy system was sampled intensively to study the changing properties of waters as they are advected towards the open ocean in the filament and to investigate the exchanges between filament and eddies. The system was more complex than previously revealed. In early August, a single filament extended offshore from near Cape Juby. Two weeks later, a second filament had developed slightly farther north and extended offshore to merge with the first at 100 km offshore. The merged filament was entrained around a recurrent, topographically trapped cyclonic eddy and interacted with transient cyclonic and anticyclonic eddies shed from the island of Gran Canaria. Between the two filaments and the coast, a pair of counter-rotating eddies re-circulated water parcels for several weeks. Surface layer drifters cycled around this near-shore re-circulation several times before following convoluted paths that demonstrate significant exchange between continental shelf and open ocean waters.This work has been supported by the European Union (Project CANIGO, MAS3.CT96-0060). We thank the officers and crew of the BIO Hespérides, as well as the staff of the UTM (CSIC, Spain) for their invaluable help at sea. Analysis and writing up was supported by Catedra Patrimonial EX-010009 (Conacyt) while E.D.B. was on sabbatical leave at CICESE, Mexico.Peer reviewe

    CO2 antropogénico en la región de las Azores

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    The AZORES-I cruise was conducted in August 1998, spanning the length of three latitudinal large-scale sections at 22, 28 and 32ºW. The oceanic carbon system was oversampled by measuring total alkalinity, total inorganic carbon and pH. It is thus possible to estimate anthropogenic CO2 (CANT) and to investigate its relationship with the main water masses that are present. C CANT is calculated using the latest back-calculation techniques: φCTº and TrOCA methods. Although the two approaches produce similar vertical distributions, the results of the TrOCA method show higher CANT variability and produce higher inventories than those of the φCTº method. The large proportion of Mediterranean Water found in the northern part of the study area is the main cause of the observed increase northwards of C CANT inventories. Changes in C CANT inventories between 1981 and 2004 are evaluated using data from the TTO-NAS, OACES-93 and METEOR-60/5 cruises. According to the φCTº and TrOCA approaches, the average long-term rates of C CANT inventory change are 1.32±0.11 mol C m-2 y-1 (P=0.008) and 1.18±0.16 mol C m-2 y-1 (P=0.018), respectively. During the 1993-1998 a significant increase in the C CANT storage rate was detected by the φCTº method. It is thought that this stems directly from the enhanced Labrador Seawater formation after the increased advection observed at the time.La campaña de macro-escala Azores I se desarrolló durante el mes de agosto de 1998 y consta de tres secciones meridionales centradas en 22, 28 y 32ºW. El sobre-muestreo realizado del sistema del carbónico, con medidas de alcalinidad total, carbono inorgánico total y pH, ha permitido el cálculo del CO2 antropogénico (CANT) e investigar su distribución en las masas de agua presentes. El CANT se calculó mediante las últimas técnicas de retro-cálculo disponibles: los métodos φCTº y TrOCA. A pesar de que ambos procedimientos producen distribuciones verticales similares, los resultados del método TrOCA indican mayores inventarios y variabilidad de CANT que los estimados por el método φCTº. La elevada proporción de agua mediterránea presente al norte de la región estudiada es la causa principal del aumento hacia el norte de los inventarios de CANT. Las tasas de cambio en los inventarios de CANT entre 1981 y 2004 se han evaluado utilizando datos de las campañas TTO-NAS, OACES-93 y METEOR-60/5. Según los métodos φCTº y TrOCA, las tasas de cambio promedio a largo plazo del inventario de CANT en esta zona son de 1.32±0.11 mol C m -2 y-1 (p-valor=0.008) y de 1.18±0.16 mol C m-2 y-2 (p-valor=0.018), respectivamente. Durante el periodo 1993-1998 el método φCTº detecta un aumento significativo de la tasa de acumulación de CANT provocado posiblemente por las elevadas tasas de formación de agua de Labrador, derivadas del aumento de la advección observada en dicho periodo

    Mesoscale eddies: Hotspots of prokaryotic activity and differential community structure in the ocean

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    14 pages, 9 figures, 2 tablesTo investigate the effects of mesoscale eddies on prokaryotic assemblage structure and activity, we sampled two cyclonic eddies (CEs) and two anticyclonic eddies (AEs) in the permanent eddy-field downstream the Canary Islands. The eddy stations were compared with two far-field (FF) stations located also in the Canary Current, but outside the influence of the eddy field. The distribution of prokaryotic abundance (PA), bulk prokaryotic heterotrophic activity (PHA), various indicators of single-cell activity (such as nucleic acid content, proportion of live cells, and fraction of cells actively incorporating leucine), as well as bacterial and archaeal community structure were determined from the surface to 2000 m depth. In the upper epipelagic layer (0-200 m), the effect of eddies on the prokaryotic community was more apparent, as indicated by the higher PA, PHA, fraction of living cells, and percentage of active cells incorporating leucine within eddies than at FF stations. Prokaryotic community composition differed also between eddy and FF stations in the epipelagic layer. In the mesopelagic layer (200-1000 m), there were also significant differences in PA and PHA between eddy and FF stations, although in general, there were no clear differences in community composition or single-cell activity. The effects on prokaryotic activity and community structure were stronger in AE than CE, decreasing with depth in both types of eddies. Overall, both types of eddies show distinct community compositions (as compared with FF in the epipelagic), and represent oceanic hotspots of prokaryotic activity (in the epi- and mesopelagic realms)This research was supported by two grants of the Spanish Ministry of Education and Science to JA (Oceanic Eddies and Atmospheric Deposition—RODA, CTM 2004-06842-C03/MAR, and Shelf–Ocean Exchanges in the Canaries– Iberian Large Marine Ecosystem-CAIBEX, CTM 2007- 66498-C02), a grant of the Earth and Life Science Division of the Dutch Science Foundation (ALW-NWO; ARCHIMEDES project, 835.20.023) to GJH, and a predoctoral Fellowship of the Spanish Ministry of Education and Science (AP2005-3932) to FB. IL and JMG were also supported by project MODIVUS (CTM2005-04795/MAR). The work was carried out within the frame of the EU ‘Networks of Excellence’ MarBef and EurOceansPeer Reviewe

    Acceptability of the HPV vaccine among Spanish university students in the pre-vaccine era: a cross-sectional study

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    Introducción. El cáncer de cuello de útero (CCU), segunda causa de mortalidad por cáncer en mujeres, está asociado a la infección por virus de papiloma humano (VPH), cuya máxima prevalencia se sitúa entre los 20 y 24 años de edad. Desde 2006 se dispone de una vacuna contra el VPH. El objetivo de este estudio es evaluar los conocimientos sobre CCU, la infección por VPH y su vacuna, valorando su aceptabilidad en población universitaria. Métodos. Estudio transversal sobre 1.750 estudiantes de la Universidad de Alicante (2008) seleccionados al azar, proporcional por sexo y estudios, mediante un cuestionario ad-hoc validado. Se calcularon porcentajes, intervalos de confianza, tablas de contingencia según sexo, edad y tipo de estudios, calculando odds ratios ajustadas (OR). Resultados. Muestra con 58,6% mujeres y 6,6% de estudiantes biosanitarios. Un 87,3% dispuestos a vacunarse frente al VPH, el 94,3% vacunaría a sus hijas, un 48,0% había oído hablar de la vacuna. El 90,6% tiene bajos conocimiento sobre la infección por VPH y un 82,2% sobre la vacuna. Un 22,4% manifiesta conocer la asociación entre VPH y CCU. Las mujeres registran OR mayores en conocimientos y predisposición a vacunarse. La aceptabilidad de la vacuna contra VPH se asocia con el sexo y la confianza en las vacunas como método preventivo, la influencia de los conocimientos previos es escasa sobre la predisposición vacunal. Conclusiones. Alta aceptabilidad de la vacuna en el periodo estudiado. Aumentar la confianza hacia las vacunas puede influir en una mejor predisposición a vacunarse.Introduction. Cervical cancer (CC), the second most common cause of cancer deaths in women, is associated with the infection of human papillomavirus (HPV) and is more prevalent in women between the ages of 20 and 24. This research is aimed to determine the background about CC, the human papillomavirus infection and its vaccine, assessing its acceptability in university students. Methods. Cross-sectional study over 1,750 students from the University of Alicante (2008) selected at random, proportional associated to gender and studies, by a validated ad-hoc questionnaire. Percentages were computed, confidence intervals, contingency tables according to sex, age and type of studies, calculating adjusted odd ratios (OR). Results. A sample with 58.6 % of women and 6.6% of biohealth students was obtained. 87.3% were willing to have the vaccine to prevent human papillomavirus (HPV), 94.3% would give this vaccine to their daughters, and 48.0% had heard someone talk about the vaccine. 90.6% didn´t have a lot of knowledge about the HPV infection and 82.2% didn´t know much about the vaccine. 22.4% had knowledge of the association between HPV and CC. Women register higher OR in acknowledging the problem and are more receptive to having the vaccine. The HPV vaccine acceptability is associated to the sex, the confidence of vaccines as a preventive method; the influence of the background is low in relation to the vaccine predisposition. Conclusions. A high acceptability of the vaccine was observed in the period of the study. Raising confidence in people about the vaccines can influence for a better predisposition to be vaccinated

    Commissions Carte de l'Espagne dans les années 1850

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    La necesidad de contar con un mapa de base científica que cubriera todo el territorio español llevó al Estado a crear en paralelo varias Comisiones con cometidos geodésicos, topográficos y cartográficos durante la década de 1850. La labor simultánea de estas Comisiones se prolongó hasta 1859, cuando se aprobó la Ley de Medición del Territorio, que las fusionó en un único organismo. Este artículo analiza aspectos técnicos de los trabajos que realizaron estas Comisiones a partir de la información contenida en algunos documentos que custodia el Archivo Topográfico del IGN. Las conclusiones que se extraen son que estas Comisiones acometieron operaciones geodésicas que resultaron cruciales en el establecimiento ulterior de la red de triangulación peninsular, realizaron mediciones topográficas que fueron reutilizadas veinte años después en el levantamiento del Mapa Topográfico Nacional, e idearon las características catastrales que fueron adoptadas durante todo el siglo posterior para el Catastro de España.The need to have a scientific map covering the whole Spanish territory led the Government in the 1850´s to the foundation of various Commissions with powers on geodesy, topography and cartography. These several Agencies worked simultaneously until 1859, when the Law on Territory Measuring was passed by Parliament and these Commissions were merged in one single Office. Technical issues of the works accomplished by these Agencies are examined in this article using information included in some of the documents held at the Topographical Archive of the National Geographical Institute of Spain. The main conclusions drawn show that the geodetic works fulfilled by these Commissions were crucial in calculating the geodetic network afterwards, their topographic measurements were reused some twenty years later for accomplishing the National Topographical Map of Spain, and their cadastral guidelines were applied during the following century to the Spanish Cadastre.La grande croissance de la production immobilière dès moitié des années 90 jusqu´en 2007 et puis la forte crise (qui ont été déjà largement décrites) ne peuvent pas, cependant, être compris sans avoir en compte des procès sociodémographiques et du territoire qui ont soutenu l´spirale de la construction immobilière. Cet article a l´objet d´analyser la relation entre la mobilité résidentielle et la création de nouveau logement dans zones métropolitaines en partant de l´hypothèse que c´est précisément celle-là le principal facteur qui stimule la construction dans ces espaces. Pour cet objectif, il a été analysé la relation statistique entre la production immobilière et les flux de mobilité résidentielle entre municipalités dans les zones métropolitaines de Madrid et Seville. Les résultats montrent un scénario dans lequel chaque municipalité a lutté pour attirer les flux de mobilité résidentielle par l´offre de nouveau logement, ce qui a produit un surdimensionnement du stock résidentiel dans ces zones urbaines

    Population distribution and biomass variability of sardine and anchovy in the Canary current system as simulated by an end-to-end coupled model

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    Small pelagic fishes as sardine and anchovy account for as much as 20-25% of the world fisheries catch. They are particularly abundant in the four major eastern boundary upwelling ecosystems, where high levels of biological productivity are sustained by the supply of nutrient-rich water from beneath the photic zone. An intrinsic and puzzling feature of small pelagic fish is the large fluctuations of their population, typically occurring at decadal scales. The causes for such fluctuations have been extensively analyzed and discussed in the literature, yet our understanding of the mechanism involved is very limited. End-to-end models are emerging tools useful to test hypothesis for such fish population variability or to gain new insights into the problem. This comprehensive and complex model approach is now becoming possible largely thanks to the present-day computer power. This contribution focuses on the population dynamics of sardine (Sardina pilchardus) and anchovy (Engraulis encrasicolus) in the Canary Current Upwelling Ecosystem. We describe and present the results of an end-to-end coupled model simulation including these two small pelagic species. The end-to-end application includes three model components: the ROMS circulation sub-model, the lower trophic ecosystem sub-model NEMURO, and a recently developed individual-based model for the fish (Rose et al. 2015; Fiechter et al. 2015). The computational grid for the three models covers NW Africa and the Western Iberian Peninsula at a spatial resolution of 12 km. This resolution is sufficient for certain eddy variability to occur in ROMS. Different biological traits were prescribed for anchovy and sardine: temperature optimum, diet preferences, and the onset and duration of the spawning season, among others. A hind-cast simulation of the period 1958-2007 was carried out. Model results reveal a fairly different behavior of sardine and anchovy. Anchovies gather off the northern part of Morocco and the Gulf of Cadiz, whereas sardines appear more scattered across the domain, further offshore, and further south, where upwelling favorable conditions take place year round. Both species exhibit decadal-scale fluctuations in both the location of the center of mass of the population and their biomass abundance; the latter being reasonably correlated with historical landing records.Universidad de Málaga. Campus de Excelencia Internacional del Mar CEIMAR. Campus de Excelencia Andalucía Tec

    Aplicación de TIG en la generación de indicadores de calidad ambiental de sistemas playa-dunas

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    Se presentan resultados parciales del subproyecto “Ecosistemas y Biodiversidad: vigilancia de espacios arenosos protegidos de Canarias y África”, incluido en el 'Programa para el desarrollo de redes tecnológicas y de aplicación de datos de teledetección en África Occidental', TELECAN (MAC/3/C181), financiado por el Programa de Cooperación Transnacional Madeira-Azores-Canarias (MAC) 2007/2013. El objetivo principal era definir, mediante el uso de imágenes de satélite, indicadores de calidad ambiental para sistemas playa-dunas, al ser éstos espacios fundamentales en el desarrollo socio-económico de estos territorios, dado su atractivo turístico. En este trabajo se presentan los resultados obtenidos para una de las áreas piloto, Maspalomas (Gran Canaria, islas Canarias). Los indicadores se obtuvieron mediante el procesado de imágenes del satélite WorldView-2, con validación, en 2013, mediante campañas marinas. Asimismo, se utilizaron imágenes de archivo, correspondientes a los años 2010, 2011 y 2012. Estos indicadores se basaron en variables relacionadas con las características físicas y biológicas de las aguas litorales y de las playas y dunas. Los resultados indican una calidad, por lo general, alta y muy alta, tanto para el medio terrestre como para el marino, con superficies dentro de estas categorías del 20,3% y 75,3% y del 26,1% y 70,6%, respectivamente.Esta es una contribución del 'Programa para el desarrollo de redes tecnológicas y de aplicación de datos de teledetección en África Occidental', TELECAN (MAC/3/C181), financiado por el Programa de Cooperación Transnacional Madeira-Azores-Canarias (MAC) 2007/2013

    Diapycnal Nutrient Fluxes in the Cape Ghir upwelling region

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    European Geosciences Union General Assembly 22-27 April 2012, Vienna, Austria.-- 1 pageAn oceanographic survey was carried out from 18 to 29 October 2010 in the Canary Basin (PROMECA project). Near Cape Ghir, in the Northwest Africa coastal upwelling, 17 CTD casts were made to obtain continuous records of conductivity and temperature with depth, and to collect waters samples for nutrients analyses. Additionally, free-fall turbulence profiles were obtained at each station. 14 Expandable bathythermographs (XBTs) were deployed between stations to increase the grid resolution of the temperature field. Velocity data were acquired with a vessel-mounted Acoustic Doppler Current Profiler (ADCP) with a vertical bin size of 8 m. Water samples for nutrients: nitrate + nitrite (N+N), phosphates and silicates, were collected from 12 depths (down to 2000 m or the maximum depth), with 12-l Niskin bottles mounted on the rosettes sampler. The first results show low to moderate concentrations of nutrients offshore, with average values in the upper 150 m of 2.45 ± 1.98, 0.37 ± 0.18 and 1.47 ± 0.94 μM for N+N, phosphate and silicate, respectively. However, for stations near the Cape Ghir upwelling filament or influenced by this feature, a significant increase in the concentration of nutrients (up to 10 µM of N+N at 200 m) was observed. We have estimated and compared the diapycnal nutrient flux in the region by using two different approaches. First, we used the dissipation rates of turbulent kinetic energy and thermal variance estimated from microstructure data acquired from turbulence profilers, and applied a model based on the dissipation ratio. This way we obtain net turbulence diffusivities in regions where there is an interaction of processes of double diffusion and turbulence induced by vertical shear of the flow. The second approach is based on obtaining diapycnal diffusivities with parameterizations of the gradient Richardson number and density ratioPeer Reviewe
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