Science.gov

Sample records for north western mediterranean

  1. Floating debris in the Ligurian Sea, north-western Mediterranean.

    PubMed

    Aliani, Stefano; Griffa, Annalisa; Molcard, Anne

    2003-09-01

    Results from visual sightings of large floating debris are presented, taken in the Ligurian Sea, a sub-basin of the north-western Mediterranean Sea which belongs to the recently stated "Cetacean Sanctuary". Data have been collected during three oceanographic cruises, during the summer of 1997 and 2000. Results for the 1997 data suggest a debris density of the order of 15-25 objects km(-2), while for the 2000 data, a lower density of the order of 3-1.5 objects km(-2) is found. The difference between the two results appears statistically significant using simple tests. Possible reasons for the observed variability are discussed, including meteorological forcing, marine currents and debris input variability.

  2. Neustonic microplastic and zooplankton in the North Western Mediterranean Sea.

    PubMed

    Collignon, Amandine; Hecq, Jean-Henri; Glagani, François; Voisin, Pierre; Collard, France; Goffart, Anne

    2012-04-01

    Neustonic microplastic and zooplankton abundance was determined in the North Western Mediterranean Sea during a summer cruise between July 9th and August 6th 2010, with a break between July 22 th and 25th due to a strong wind event. Ninety percent of the 40 stations contained microplastic particles (size 0.3-5mm) of various compositions: e.g., filaments, polystyrene, thin plastic films. An average concentration of 0.116 particles/m(2) was observed. The highest abundances (>0.36 particles/m(2)) were observed in shelf stations. The neustonic plastic particles concentrations were 5 times higher before than after the strong wind event which increased the mixing and the vertical repartition of plastic particles in the upper layers of the water column. The values rise in the same order of magnitude than in the North Pacific Gyre. The average ratio between microplastics and mesozooplankton weights was 0.5 for the whole survey and might induce a potential confusion for zooplankton feeders.

  3. Vortices generation mechanisms in North western Mediterranean Sea

    NASA Astrophysics Data System (ADS)

    Fraunie, P.; Redondo, J. M.; Schaeffer, A.; Molcard, A.; Forget, P.; Garreau, P.

    2012-04-01

    Mesoscale eddies have been observed in Northwestern Mediterranean Sea from satellites, RV cruises and more recently using HF radars. Different non linear mechanisms have been identified and investigated using process oriented high resolution numerical modelling. In particular, wind induced inertial motion and baroclinic instability cases have been illustrated and documented. Statistics of vortices occurence allow a better accounting for coherent structures for pollutants and nutriments dispersion and retention. Acknowledgements : GIRAC project (FUI - CG83 -TPM), ESA, HYMEX programme

  4. Barotropic eastward currents in the western Gulf of Lion, north-western Mediterranean Sea, during stratified conditions

    NASA Astrophysics Data System (ADS)

    Petrenko, A.; Dufau, C.; Estournel, C.

    2008-11-01

    The circulation of the Gulf of Lion, a large continental shelf north of the western basin of the Mediterranean Sea, is complex and highly variable. During stratified conditions, unexpected barotropic eastward currents can be detected, mostly in the western part of the gulf. Care is given to retrieve inertial oscillations when necessary. The primitive-equation free-surface model Symphonie is used to investigate the processes which can generate and influence these eastward currents. Three main wind forcing create these barotropic eastward currents: northwesterlies channelled in the western part of the gulf, northwesterlies and north winds both homogeneous throughout the gulf. In the first case, the wind stress curl of the channeled northwesterlies generates an elongated cyclonic circulation in the western part of the Gulf of Lion. The southern part of this cyclonic circulation is a barotropic eastward current, detected west of longitude 4.5°E. In the second case, a homogeneous northwesterly wind creates an intrusion of the along-slope geostrophic current on the shelf, generating a strong coastal jet going northward above Cap Creus. In stratified conditions, intrusion at this western end of the continental shelf only occurs during this type of wind forcing. The coastal jet goes north then detaches itself from the coast and goes eastward, north of the 100 m isobath. In the third case, a homogeneous north wind creates an eastward current which occupies the whole shelf north of latitude 43°N. The first two cases are studied in more details since cruise data corroborate the model simulations. The striking characteristic of these eastward currents is that they are barotropic despite the stratified conditions. Otherwise, their amplitude and exact locations are slightly different for the different cases of circulation. These eastward currents probably have an impact on the residence time of water masses in the Gulf of Lion, and hence on the total water budget of the gulf

  5. "Scale oriented" embedded modeling of the North-Western Mediterranean in the frame of MFSTEP

    NASA Astrophysics Data System (ADS)

    Estournel, C.; Auclair, F.; Lux, M.; Nguyen, C.; Marsaleix, P.

    2007-02-01

    An embedded forecasting system was developed for the North-Western Mediterranean including a regional model and a coastal model of the Gulf of Lion. The system is based on the Symphonie hydrodynamic free surface model and on the variational initialization and forcing platform VIFOP. It was shown that a pre-modeling period of 7 days before beginning the forecast allows the growth of the small scales. The embedded forecasts have been compared to the MFS observing system. It was basically found that in the North-Western Mediterranean, the MFS basin-scale model and thus the regional model forecasts are characterized by large negative biases of salinity in the first 100 m under the surface leading thus to too light subsurface waters. The underestimation of temperature by the regional model just below the surface and its overestimation at 30 m deep can be associated to an overestimation of the turbulent mixing. The regional and coastal models allow to represent a number of processes especially those induced by the wind as coastal upwelling under stratified conditions, dense water formation over the Gulf of Lion shelf, deep mixing in the convection zone or influence on the Northern Current penetration in the Gulf of Lion.

  6. "Scale oriented" embedded modeling of the North-Western Mediterranean in the frame of MFSTEP

    NASA Astrophysics Data System (ADS)

    Estournel, C.; Auclair, F.; Lux, M.; Nguyen, C.; Marsaleix, P.

    2009-04-01

    An embedded forecasting system was developed for the North-Western Mediterranean at 3-km resolution. The system is based on the Symphonie hydrodynamic free surface model and on the variational initialization and forcing platform VIFOP. The regional model is initialized and forced at its open lateral boundaries by the MFS GCM and forced at the surface by the ALADIN numerical weather prediction model. Once a week, a five-day forecast is produced after a hindcast of seven days. This pre-modeling period of 7 days before beginning the forecast allows the development of the small scale features associated to the high resolution. The relevance of the 5-day forecast strategy has been examined by comparing the forecasted fields to hindcast fields (forced by meteorological and oceanic analyses) considered as a reference. Mismatches remain at a very low level indicating a good quality of the forecasted forcing fields and also possibly to the strong wind conditions which prevailed during the period. The embedded forecasts have been compared to the MFS observing system (SST and MedArgo) during 6 forecast cycles between September 2004 and February 2005. It was basically found that in the North-Western Mediterranean, the MFS basin-scale model and thus the regional model forecasts are characterized by large negative biases of salinity in the first 100 m under the surface leading thus to too light subsurface waters. The underestimation of temperature by the regional model just below the surface and its overestimation at 30m deep can be attributed to an overestimation of the turbulent mixing. The regional model allows to represent a number of processes especially those induced by the wind as coastal upwelling under stratified conditions, dense water formation over the Gulf of Lion shelf, deep mixing in the convection zone or influence on the Northern Current penetration in the Gulf of Lion.

  7. Lagrangian analysis of satellite-derived currents: Application to the North Western Mediterranean coastal dynamics

    NASA Astrophysics Data System (ADS)

    Bouffard, Jerome; Nencioli, Francesco; Escudier, Romain; Doglioli, Andrea Michelangelo; Petrenko, Anne A.; Pascual, Ananda; Poulain, Pierre-Marie; Elhmaidi, Dalila

    2014-03-01

    Optimal interpolation methods for improving the reconstruction of coastal dynamics from along-track satellite altimetry measurements have been recently developed over the North Western Mediterranean Sea. Maps of satellite-derived geostrophic current anomalies are generated using these methods, and added to different mean circulation fields in order to obtained absolute geostrophic currents. The resulting fields are then compared to standard AVISO products, and their accuracies are assessed with Lagrangian diagnostics. The trajectories of virtual particle clusters are simulated with a Lagrangian code either with new current fields or with the AVISO ones. The simulated trajectories are then compared to 16 in situ drifter trajectories to evaluate the performance of the different velocity fields. The comparisons show that the new current fields lead to better results than the AVISO one, especially over the shallow continental shelf of the Gulf of Lion. However, despite the use of innovative strategies, some altimetry limitations still persist in the coastal domain, where small scale processes remain sub-sampled by conventional altimetry coverage but will benefit from technological development in the near future. Some of the limitations of the Lagrangian diagnostics presently used are also analyzed, but dedicated studies will be required for future further investigations.

  8. Time variability of the north-western Mediterranean Sea pH over 1995-2011.

    PubMed

    Marcellin Yao, Koffi; Marcou, Olivier; Goyet, Catherine; Guglielmi, Véronique; Touratier, Franck; Savy, Jean-Philippe

    2016-05-01

    Factors controlling ocean acidification and its temporal variations were studied over the 1995-2011 period at the Dyfamed site at 10 m depth, in the North Mediterranean Sea. The results indicated a mean annual decrease of 0.003 ± 0.001 pH units on the seawater scale. The seasonal variability was characterized by a pH decrease during springtime and a strong pH increase in late fall. Anthropogenic CO2 (CANT) absorption by the ocean was the key driver of seawater acidification in this region, accounting for about 70% of the observed drop in pH, followed by water temperature (about 30%). The total inorganic carbon (CT) data showed a CT increase of 30.0 ± 1.0 μmol kg(-1) per decade. This decadal increase is mainly due to the CANT penetration (43.2 μmol kg(-1) per decade) in surface waters, which is mitigated for by relatively small opposing changes in CT due to physical and biological processes. PMID:26994464

  9. Holocene climate variability in the North-Western Mediterranean Sea (Gulf of Lions)

    NASA Astrophysics Data System (ADS)

    Jalali, B.; Sicre, M.-A.; Bassetti, M.-A.; Kallel, N.

    2016-01-01

    Sea surface temperatures (SSTs) and land-derived input time series were generated from the Gulf of Lions inner-shelf sediments (NW Mediterranean Sea) using alkenones and high-molecular-weight odd-carbon numbered n-alkanes (TERR-alkanes), respectively. The SST record depicts three main phases: a warm Early Holocene ( ˜ 18 ± 0.4 °C) followed by a cooling of ˜ 3 °C between 7000 and 1000 BP, and rapid warming from ˜ 1850 AD onwards. Several superimposed multi-decadal to centennial-scale cold events of ˜ 1 °C amplitude were also identified. TERR-alkanes were quantified in the same sedimentary horizons to identify periods of high Rhone River discharge and compare them with regional flood reconstructions. Concentrations show a broad increase from the Early Holocene towards the present with a pronounced minimum around 2500 BP and large fluctuations during the Late Holocene. Comparison with Holocene flood activity reconstructions across the Alps region suggests that sediments of the inner shelf originate mainly from the Upper Rhone River catchment basin and that they are primarily delivered during positive North Atlantic Oscillation (NAO).

  10. Late Holocene climate change in the western Mediterranean: centennial-scale vegetation and North Atlantic Oscillation variability

    NASA Astrophysics Data System (ADS)

    Ramos Román, M. J.; Jimenez-Moreno, G.; Anderson, R. S.; García-Alix, A.; Toney, J. L.; Jiménez-Espejo, F. J. J.; Carrión, J. S.

    2015-12-01

    Sediments from alpine peat bogs and lakes from the Sierra Nevada in southeastern Spain (western Mediterranean area) have been very informative in terms of how vegetation and wetland environments were impacted by past climate change. Recently, many studies try to find out the relationship between solar activity, atmosphere and ocean dynamics and changes in the terrestrial environments. The Mediterranean is a very sensitive area with respect to atmospheric dynamics due to (1) its location, right in the boundary between subtropical and temperate climate systems and (2) the North Atlantic Oscillation (NAO) is one of the main mechanism that influence present climate in this area. Here we present a multi-proxy high-resolution study from Borreguil de la Caldera (BdlC), a peat bog that records the last ca. 4500 cal yr BP of vegetation, fire, human impact and climate history from the Sierra Nevada. The pollen, charcoal and non-pollen palynomorphs (NPPs) reconstruction in the BdlC-01 record evidence relative humidity changes in the last millennia interrupting the late Holocene aridification trend. This study shows a relative arid period between ca. 4000 and 3100 cal yr BP; the Iberian Roman humid period (ca. 2600 to 1600 cal yr BP); a relative arid period during the Dark Ages (from ca. AD 500 to AD 900) and Medieval Climate Anomaly (from ca. AD 900 to ca. AD 1300) and predominantly wetter conditions corresponding with The Little Ice Age period (from ca. AD 1300 to AD 1850). This climate variability could be explained by centennial scale changes in the NAO and solar activity.

  11. Downward and suspended sediment fluxes in the Palamós submarine canyon (North-Western Mediterranean)

    NASA Astrophysics Data System (ADS)

    Palanques, A.; Martín, J.; Puig, P.; Guillén, J.

    2003-04-01

    The Palamós canyon is deeply incised in the Northern Catatonia continental shelf (North-western Mediterranean) which favour an active shelf-slope sediment transfer. To study particle dynamics in this canyon, seven moorings arrays equipped with current meters, turbidimeters and sediment traps were deployed near the bottom along the main canyon axis (400, 1200 and 1700 m depth), on both canyon walls (1200 m depth) and on the adjacent slope (1200 m depth). One set of these instruments was also deployed at intermediate waters (400 m water depth) in the canyon axis. At surface and mid-depths, suspended sediment fluxes were oriented along the mean flow direction (NE-SW), whereas near-bottom sediment fluxes were more constrained by the local bathymetry. The higher near-bottom downward and suspended particle fluxes were not recorded in the canyon head but in the mid-canyon axis, suggesting additional sediment supplies through or over the canyon walls and/or sediment resuspension in the mid canyon region. Several events of sharp sediment flux increases took place in the mid-canyon axis site during the water stratification season. These events could be related to the action of internal waves and even to fishing activities. In the canyon walls, downward and suspended particle fluxes were higher in the southern wall, where currents were lower than in the northern wall, evidencing an asymmetrical pattern. In the adjacent slope sediment fluxes were significantly lower than in the canyon. An important increase of downward particle fluxes in the canyon axis and both walls occurred by mid-November when a severe storm took place. The pattern of the sediment fluxes in the Palamós Canyon has some differences in relation to those observed in other Mediterranean submarine canyons and has downward particle fluxes from 2 to10 times higher than other studied canyons of this region.

  12. Deep phylogeographic divisions and long-term persistence of forest invertebrates (Hexapoda: Collembola) in the North-Western Mediterranean basin.

    PubMed

    Cicconardi, F; Nardi, F; Emerson, B C; Frati, F; Fanciulli, P P

    2010-01-01

    The North-Western Mediterranean basin is well known for its high number of relictual endemic taxa, and has been indicated as one of the world's major biodiversity hotspots at the species level. A possible contributing factor may be long-term persistence of populations and their prolonged stability. This study was designed to investigate the phylogeographic structure of three common species of the genus Lepidocyrtus (Hexapoda: Collembola), soil-dwelling arthropods characterized by limited dispersal capabilities and generally associated with forest habitats. We observed a remarkable geographic structure, with numerous deeply divergent genetic lineages occupying islands as well as mainland sites with no apparent gene flow among most sites, even across distances of only tens of kilometres. The reconstructed time frame for the evolution of these lineages suggests divergence between 5 and 15 Ma. This indicates a remarkably ancient origin and long-term persistence of individual lineages over a fine geographic scale despite the occurrence of abrupt sea level and climatic fluctuations in the area. This further suggests that currently recognized morphological species might be a serious underestimation of the true springtail biodiversity within this region. PMID:20015142

  13. Structure and Dynamics of North-western Mediterranean Rocky Benthic Communities along a Depth Gradient

    NASA Astrophysics Data System (ADS)

    Garrabou, J.; Ballesteros, E.; Zabala, M.

    2002-09-01

    The structure and dynamics of four Mediterranean communities along a depth gradient (5 to 20 m depth) were investigated. The main environmental factors relevant to the organization of benthic communities varied predictably with depth, decreasing both in magnitude and in temporal variability. The following hypotheses were tested on the organization of communities as depth increases: (1) community structure increases in complexity, (2) community dynamics decrease, and (3) temporal (seasonal) variations both in community structure and dynamics become dampened. A series of photographs (310 cm2 each) of 12 permanent plots were taken monthly over a 2-year period. Plots belonged to one of four communities, two algal- and two animal-dominated by animals. In the analysis of photographs, a novel methodological approach was employed using techniques borrowed from landscape ecology. Community structure was quantified using three landscape pattern indices: number of patches, mean patch size and Shannon's diversity index. Community dynamics were measured by calculating spatially explicit area changes over time by overlaying drawings corresponding to different sampling times. The results support the hypotheses tested. Firstly, the shallower, algae-dominated communities, had, in general, significantly lower structure (i.e. patch-mosaics were less heterogeneous), than were deeper communities dominated by animals. Secondly, community dynamics were significantly larger in shallower communities than in deeper communities. Thirdly, temporal changes in community structure and dynamics were generally dampened with depth showing, in some cases, significant temporal patterns in structure and dynamics, which were consistent with seasonal variations. These depth-related trends in community structure and dynamics in subtidal Mediterranean communities may respond to strong changes in community determining factors (nutrient availability, physical disturbance, predation). Finally, it is

  14. Invasion of Mediterranean Annual Grasses in Western North America Ecosystems: Kids in a Candy Store

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In this issue of Plant and Soil, Blank and Sforza (2007) contribute to a growing body of work focused on describing mechanisms by which exotic annual grasses invade ecosystems in the western United States. Their findings, that medusahead wildrye (Taeniatherum caput-medusae [L.] Nevski) was most pro...

  15. Holocene climate variability in the North-Western Mediterranean Sea (Gulf of Lions)

    NASA Astrophysics Data System (ADS)

    Jalali, B.; Sicre, M.-A.; Bassetti, M.-A.; Kallel, N.

    2015-07-01

    Sea surface temperatures (SSTs) and land-derived input time series were generated from the Gulf of Lions inner-shelf sediments (NW Mediterranean Sea) using alkenones and high-molecular-weight odd-carbon numbered n-alkanes (TERR-alkanes), respectively. The SST record depicts three main phases: a warm Early Holocene (∼ 18 ± 0.4 °C) followed by a cooling of ∼ 3 °C (from 7000 to 1000 BP) and rapid warming from ∼ 1850 AD onwards. Several superimposed multi-decadal cooling events of ∼ 1 °C amplitude were also identified. TERR-alkanes were also quantified to identify periods of high river discharge in relation with flood events of the Rhone River and precipitations. Their concentrations show a broad increase from the early Holocene towards present with a pronounced minimum around 2500 BP and large fluctuations during the second part of the Holocene. Comparison with Holocene flood activity reconstructions across the Alps region suggests that sediments of the inner shelf originate mainly from the Upper Rhone River catchment basin and that they are primarily delivered during positive NAO.

  16. Long-range transport and mixing of aerosol sources during the 2013 North American biomass burning episode: analysis of multiple lidar observations in the western Mediterranean basin

    NASA Astrophysics Data System (ADS)

    Ancellet, Gerard; Pelon, Jacques; Totems, Julien; Chazette, Patrick; Bazureau, Ariane; Sicard, Michaël; Di Iorio, Tatiana; Dulac, Francois; Mallet, Marc

    2016-04-01

    Long-range transport of biomass burning (BB) aerosols between North America and the Mediterranean region took place in June 2013. A large number of ground-based and airborne lidar measurements were deployed in the western Mediterranean during the Chemistry-AeRosol Mediterranean EXperiment (ChArMEx) intensive observation period. A detailed analysis of the potential North American aerosol sources is conducted including the assessment of their transport to Europe using forward simulations of the FLEXPART Lagrangian particle dispersion model initialized using satellite observations by MODIS and CALIOP. The three-dimensional structure of the aerosol distribution in the ChArMEx domain observed by the ground-based lidars (Minorca, Barcelona and Lampedusa), a Falcon-20 aircraft flight and three CALIOP tracks, agrees very well with the model simulation of the three major sources considered in this work: Canadian and Colorado fires, a dust storm from western US and the contribution of Saharan dust streamers advected from the North Atlantic trade wind region into the westerlies region. Four aerosol types were identified using the optical properties of the observed aerosol layers (aerosol depolarization ratio, lidar ratio) and the transport model analysis of the contribution of each aerosol source: (i) pure BB layer, (ii) weakly dusty BB, (iii) significant mixture of BB and dust transported from the trade wind region, and (iv) the outflow of Saharan dust by the subtropical jet and not mixed with BB aerosol. The contribution of the Canadian fires is the major aerosol source during this episode while mixing of dust and BB is only significant at an altitude above 5 km. The mixing corresponds to a 20-30 % dust contribution in the total aerosol backscatter. The comparison with the MODIS aerosol optical depth horizontal distribution during this episode over the western Mediterranean Sea shows that the Canadian fire contributions were as large as the direct northward dust outflow

  17. Long range transport and mixing of aerosol sources during the 2013 North American biomass burning episode: analysis of multiple lidar observations in the Western Mediterranean basin

    NASA Astrophysics Data System (ADS)

    Ancellet, G.; Pelon, J.; Totems, J.; Chazette, P.; Bazureau, A.; Sicard, M.; Di Iorio, T.; Dulac, F.; Mallet, M.

    2015-11-01

    Long range transport of biomass burning (BB) aerosols between North America and the Mediterranean region took place in June 2013. A large number of ground based and airborne lidar measurements were deployed in the Western Mediterranean during the Chemistry-AeRosol Mediterranean EXperiment (ChArMEx) intensive observation period. A detailed analysis of the potential North American aerosol sources is conducted including the assessment of their transport to Europe using forward simulations of the FLEXPART Lagrangian particle dispersion model initialized using satellite observations by MODIS and CALIOP. The three dimensional structure of the aerosol distribution in the ChArMEx domain observed by the ground-based lidars (Menorca, Barcelona and Lampedusa), a Falcon-20 aircraft flight and three CALIOP tracks, agree very well with the model simulation of the three major sources considered in this work: Canadian and Colorado fires, a dust storm from Western US and the contribution of Saharan dust streamers advected from the North Atlantic trade wind region into the Westerlies region. Four aerosol types were identified using the optical properties of the observed aerosol layers (aerosol depolarization ratio, lidar ratio) and the transport model analysis of the contribution of each aerosol source: (I) pure BB layer, (II) weakly dusty BB, (III) significant mixture of BB and dust transported from the trade wind region (IV) the outflow of Saharan dust by the subtropical jet and not mixed with BB aerosol. The contribution of the Canadian fires is the major aerosol source during this episode while mixing of dust and BB is only significant at altitude above 5 km. The mixing corresponds to a 20-30 % dust contribution in the total aerosol backscatter. The comparison with the MODIS AOD horizontal distribution during this episode over the Western Mediterranean sea shows that the Canadian fires contribution were as large as the direct northward dust outflow from Sahara.

  18. Mineral dust deposition in Western Mediterranean basin

    NASA Astrophysics Data System (ADS)

    Vincent, Julie; Laurent, Benoit; Bergmatti, Gilles; Losno, Rémi; Bon Nguyen, Elisabeth; Chevaillier, Servanne; Roulet, Pierre; Sauvage, Stéphane; Coddeville, Patrice; Ouboulmane, Noura; Siour, Guillaume; Tovar Sanchez, Antonio; Massanet, Ana; Morales Baquero, Rafael; Di Sarra, Giogio; Sferlazzo, Damiano; Dulac, François; Fornier, Michel; Coursier, Cyril

    2014-05-01

    North African deserts are the world's largest sources of atmospheric mineral dust produced by aeolian erosion. Saharan dust is frequently transported toward Europe over the Mediterranean basin. When deposited in oceanic areas, mineral dust can constitute a key input of nutrients bioavailable for the oceanic biosphere. For instance, Saharan dust deposited in the in the Mediterranean Sea can be a significant source of nutrient like Fe, P and N during summer and autumn. Our objective is to study the deposition Saharan mineral dust in the western Mediterranean basin and to improve how deposition processes are parameterized in 3D regional models. To quantify the deposition flux of Saharan dust in the western Mediterranean region a specific collector (CARAGA) to sample automatically the insoluble atmospheric particle deposition was developed (LISA-ICARE) and a network of CARAGA collectors have been set up. Since 2011, eight CARAGA are then deployed in Frioul, Casset, Montandon and Ersa in France, Mallorca and Granada in Spain, Lampedusa in Italia, and Medenine in Tunisia, along a South-North gradient of almost 2000km from the North African coast to the South of Europe. We observe 10 well identified dust Saharan deposition events at Lampedusa and 6 at Mallorca for a 1-yr sampling period. These dust events are sporadic and the South-North gradient of deposition intensity and frequency is observed (the highest dust mass sampled at the stations are : 2,66 g.m-2 at Lampedusa ; 0,54 g.m-2 at Majorque ; 0,33 g.m-2 at Frioul ; 0,16 g.m-2 at Casset). The ability of the CHIMERE model to reproduce the deposition measurements is tested. The mineral dust plumes simulated over the western Mediterranean basin are also compared to satellite observations (OMI, MODIS) and in-situ measurements performed during the ChArMEx campaign and in the AERONET stations.

  19. Characterizing, modelling and understanding the climate variability of the deep water formation in the North-Western Mediterranean Sea

    NASA Astrophysics Data System (ADS)

    Somot, Samuel; Houpert, Loic; Sevault, Florence; Testor, Pierre; Bosse, Anthony; Taupier-Letage, Isabelle; Bouin, Marie-Noelle; Waldman, Robin; Cassou, Christophe; Sanchez-Gomez, Emilia; Durrieu de Madron, Xavier; Adloff, Fanny; Nabat, Pierre; Herrmann, Marine

    2016-08-01

    Observing, modelling and understanding the climate-scale variability of the deep water formation (DWF) in the North-Western Mediterranean Sea remains today very challenging. In this study, we first characterize the interannual variability of this phenomenon by a thorough reanalysis of observations in order to establish reference time series. These quantitative indicators include 31 observed years for the yearly maximum mixed layer depth over the period 1980-2013 and a detailed multi-indicator description of the period 2007-2013. Then a 1980-2013 hindcast simulation is performed with a fully-coupled regional climate system model including the high-resolution representation of the regional atmosphere, ocean, land-surface and rivers. The simulation reproduces quantitatively well the mean behaviour and the large interannual variability of the DWF phenomenon. The model shows convection deeper than 1000 m in 2/3 of the modelled winters, a mean DWF rate equal to 0.35 Sv with maximum values of 1.7 (resp. 1.6) Sv in 2013 (resp. 2005). Using the model results, the winter-integrated buoyancy loss over the Gulf of Lions is identified as the primary driving factor of the DWF interannual variability and explains, alone, around 50 % of its variance. It is itself explained by the occurrence of few stormy days during winter. At daily scale, the Atlantic ridge weather regime is identified as favourable to strong buoyancy losses and therefore DWF, whereas the positive phase of the North Atlantic oscillation is unfavourable. The driving role of the vertical stratification in autumn, a measure of the water column inhibition to mixing, has also been analyzed. Combining both driving factors allows to explain more than 70 % of the interannual variance of the phenomenon and in particular the occurrence of the five strongest convective years of the model (1981, 1999, 2005, 2009, 2013). The model simulates qualitatively well the trends in the deep waters (warming, saltening, increase in the

  20. Surface waters are a source of polychlorinated biphenyls to the coastal atmosphere of the North-Western Mediterranean Sea.

    PubMed

    García-Flor, Nuria; Dachs, Jordi; Bayona, Josep M; Albaigés, Joan

    2009-05-01

    Atmospheric (gaseous and particulate) and seawater (dissolved and particulate in the surface microlayer and underlying waters) samples were collected in 2001 and 2002 in two North-Western Mediterranean contrasting coastal environments, Banyuls-sur-Mer (France) and Barcelona (Spain). The total aerosol suspended particle concentrations (microg m(-3)) were higher in Barcelona (266+/-132) than in Banyuls-sur-Mer (149+/-43), even under near-gale conditions. The influence of the marine aerosol in the total suspended particles (TSP) concentration was backed by both organic carbon (OC) and elemental carbon (EC) concentrations, as they exhibited lower levels in Banyuls (3+/-2 microg OC m(-3) and 0.4+/-0.3 microg EC m(-3)) than in Barcelona (31+/-26 microg OC m(-3) and 6+/-8 microg EC m(-3)). Moreover, samples from Barcelona, both atmospheric and seawater, showed greater variability than in Banyuls (Snedecor's test (p<0.001)) possibly reflecting the influence of urban sources of pollutants. Concentrations of atmospheric PCBs (Sigma41 congeners) off-shore Barcelona ranged from 389 to 1410 pg m(-3) in the gas phase and from 71 to 78 pg m(-3) in the aerosol phase. In Banyuls, concentrations were 30.7-858 pg m(-3) in the gas phase and 12.8-41.2 pg m(-3) in the aerosol phase. Their gas-particle partitioning suggested that PCBs in the samples were close to equilibrium (deduced from the regression of the experimental logK(p) and logP(l)(0)). Moreover, a positive correlation was found between wind direction, wind speed and atmospheric PCB concentrations, which is consistent with the fact the PCB concentration of the marine waters, influenced by coastal run-off, become a secondary source for these semi-volatile compounds after volatilization to the coastal atmosphere. This is supported by the high dissolved concentrations in the coastal surface waters, and specially by the enrichment found in the surface microlayer.

  1. The fate of Cystoseira crinita, a forest-forming Fucale (Phaeophyceae, Stramenopiles), in France (North Western Mediterranean Sea)

    NASA Astrophysics Data System (ADS)

    Blanfuné, A.; Boudouresque, C. F.; Verlaque, M.; Thibaut, T.

    2016-11-01

    In the Mediterranean Sea, Fucales, and in particular the species of the genus Cystoseira C. Agardh, are habitat-forming species dominating several benthic assemblages from the littoral fringe down to 70-80 m depth in the clearest waters. They generate high primary production involved in the maintenance of diversified trophic levels, they provide shelter, food, habitat and nursery areas to many species, and they are long-lived species that constitute a good model for studying human impact on species diversity. Cystoseira crinita Duby is a Mediterranean endemic cespitose species, living in shallow waters (0-5 m depth), in places with little wave action and high solar irradiance. To reconstruct the long-term patterns of change in its distribution along the French Mediterranean coast (French Catalonia, Languedoc, Provence, French Riviera and Corsica), all the historical data (published articles, unpublished reports and herbarium vouchers) collected since the 18th century were searched and analysed. To assess the current status of the species, several field surveys were conducted between 2010 and 2016 by snorkelling and SCUBA diving. Cystoseira crinita is currently extinct in French Catalonia, near-extinct in Languedoc and western Provence, and functionally extinct on the French Riviera coast, while the eastern Provence and Corsican populations have remained stable. The main probable causes of decline are habitat destruction and overgrazing by herbivores.

  2. Characteristics of Geostrophic Eddies in the North Western Mediterranean as observed by Gliders and simulated by a high-resolution Model: formation, behaviour and dissipation

    NASA Astrophysics Data System (ADS)

    Bosse, Anthony; Testor, Pierre; Mortier, Laurent; Damien, Pierre; Estournel, Claude; Marsaleix, Patrick; Beguery, Laurent; Bernardet, Karim; Taillandier, Vincent; d'Ortenzio, Fabrizio; Prieur, Louis; Coppola, Laurent; Bourrin, François

    2013-04-01

    Since 2008, gliders repeated transects crossing the basin of the North Western Mediterranean Sea and regularly sampled mesoscale structures with an high horizontal resolution of about 2-3 km between each profile required in that region of small internal deformation radius (<10km). By analysing more than 50 000 profiles collected by these gliders in the last 5 years, we were able to identify several types of eddies regarding the water mass composing their cores: Winter Intermediate Water (WIW), Levantine Intermediate Water (LIW), Western Mediterranean Deep Water (WMDW). Most of them are anticyclonic structures with Rossby Number greater than 0.1 and tend to be characterized by a core in the inner ocean. Some of them whose formation has been dated several months back in time can be qualified as long lived features. Of particular interest to assess the role of mesoscale eddies in the ocean circulation, a Submesoscale Coherent Vortex (SCV) composed of newly WMDW was observed nine months after its formation. We also used a 1 year run of a high resolution (1km, 40 vertical levels) numerical model of the region (SYMPHONIE) which is able to reproduce similar eddies. In this study we discuss their formation process (instability of the boundary current, or diapycnal mixing followed by geostrophic adjustment) based on comparisons between these observations and the model outputs, and try to estimate their impact on the general circulation of this basin.

  3. Detection and Characterization of Deep-coral Banks in the Cap de Creus Canyon (North western Mediterranean) Using Visual and Acoustic Methods

    NASA Astrophysics Data System (ADS)

    Orejas, C.; Lo Iacono, C.; Gori, A.; Gili, J.; Puig, P.

    2007-12-01

    Dense banks of the white coral Madrepora oculata and Lophelia pertusa have been visually detected along the walls of the Cap de Creus Canyon, north-western Mediterranean, by using ROVs and the man submersible JAGO (IFM-GEOMAR) during three cruises (October 2005, July 2006, September 2007), in the walls of the Cap de Creus canyon (North-western Mediterranean), by 200-400 m depth range. The obtained images offered valuable information for the characterization of the communities (species composition) and abundance of the coral species as well as the conservation stage of them. We identified several patches and sampled selectively organisms in order to identify and set up experimental ecological work with coral species (feeding and physiological ecology). Visual inspections were complemented with two sidescan sonar surveys, carried out in the study area in February and April 2007, using the C-Max 2 model operating at 100 kHz. Acoustic mapping turned out to be a reliable tool in the study of coral facies, offering the possibility to survey greater areas than the ones covered with visual inspections. Moreover, sidescan sonar images gave accurate information about the seafloor backscatter, and some of the high-reflective patches could suggest the presence of corals. During the last survey, carried out in September 2007, we assay to calibrate the side scan sonar images using the video images from the JAGO, During the surveys we also analysed the water composition (Particulate Organic Carbon, C/N and Nutrients), as well as the planktonic community close to the sea floor in order to have a comprehensive picture of the whole system.

  4. Lonely populations in the deep: genetic structure of red gorgonians at the heads of submarine canyons in the north-western Mediterranean Sea

    NASA Astrophysics Data System (ADS)

    Pérez-Portela, Rocío; Cerro-Gálvez, Elena; Taboada, Sergi; Tidu, Carlo; Campillo-Campbell, Carolina; Mora, Joan; Riesgo, Ana

    2016-09-01

    The red gorgonian Paramuricea clavata plays a central role in coralligenous ecosystems of the Mediterranean Sea, being relatively abundant in shallow habitats (5-35 m depth). Recently, deeper populations have been discovered at the heads of submarine canyons in the north-western Mediterranean Sea, between 50 and 70 m deep. Colonies from some of these deeper populations were exceptionally large (>1 m high), contrasting with the general prevalence of smaller size classes in shallower populations. Importantly, the high pressure of trawling activities on the nearby continental shelf could threaten these populations of large and old colonies. Although the genetic diversity and structure of populations in shallow habitats is relatively well known, very little is known about deeper populations. We aimed to assess the genetic structure, connectivity and potential demographic decline of six deep populations of P. clavata located at the heads of La Fonera, Blanes and Arenys de Mar submarine canyons, as well as potential gene flow between those and the two nearest shallow populations. A total of 188 individuals were genotyped using nine microsatellite loci. Results showed strong genetic differentiation among populations in different submarine canyons, among populations within one of the canyons and between shallow and deep populations. Gene flow among populations was very limited, estimates of effective population size in some populations were small, and evidence of recent population reductions (bottlenecks) was detected in several populations. The large genetic differentiation in populations of P. clavata among canyons is related to limited effective dispersal.

  5. Marine litter on Mediterranean shores: Analysis of composition, spatial distribution and sources in north-western Adriatic beaches.

    PubMed

    Munari, Cristina; Corbau, Corinne; Simeoni, Umberto; Mistri, Michele

    2016-03-01

    Marine litter is one descriptor in the EU Marine Strategy Framework Directive (MSFD). This study provides the first account of an MSFD indicator (Trends in the amount of litter deposited on coastlines) for the north-western Adriatic. Five beaches were sampled in 2015. Plastic dominated in terms of abundance, followed by paper and other groups. The average density was 0.2 litter items m(-2), but at one beach it raised to 0.57 items m(-2). The major categories were cigarette butts, unrecognizable plastic pieces, bottle caps, and others. The majority of marine litter came from land-based sources: shoreline and recreational activities, smoke-related activities and dumping. Sea-based sources contributed for less. The abundance and distribution of litter seemed to be particularly influenced by beach users, reflecting inadequate disposal practices. The solution to these problems involves implementation and enforcement of local educational and management policies. PMID:26725754

  6. Marine litter on Mediterranean shores: Analysis of composition, spatial distribution and sources in north-western Adriatic beaches.

    PubMed

    Munari, Cristina; Corbau, Corinne; Simeoni, Umberto; Mistri, Michele

    2016-03-01

    Marine litter is one descriptor in the EU Marine Strategy Framework Directive (MSFD). This study provides the first account of an MSFD indicator (Trends in the amount of litter deposited on coastlines) for the north-western Adriatic. Five beaches were sampled in 2015. Plastic dominated in terms of abundance, followed by paper and other groups. The average density was 0.2 litter items m(-2), but at one beach it raised to 0.57 items m(-2). The major categories were cigarette butts, unrecognizable plastic pieces, bottle caps, and others. The majority of marine litter came from land-based sources: shoreline and recreational activities, smoke-related activities and dumping. Sea-based sources contributed for less. The abundance and distribution of litter seemed to be particularly influenced by beach users, reflecting inadequate disposal practices. The solution to these problems involves implementation and enforcement of local educational and management policies.

  7. The Devil We Don't Know: Investigating Habitat and Abundance of Endangered Giant Devil Rays in the North-Western Mediterranean Sea

    PubMed Central

    Notarbartolo di Sciara, Giuseppe; Lauriano, Giancarlo; Pierantonio, Nino; Cañadas, Ana; Donovan, Greg; Panigada, Simone

    2015-01-01

    The giant devil ray Mobula mobular, the only Mediterranean mobulid, is subject to mortality caused by directed and accidental captures in fisheries throughout the region. Whilst the combination of human impacts, limited range and a low reproductive potential is not inconsistent with its endangered listing, there are insufficient data to enable a quantitative assessment of trends. Without this, it is difficult to assess and prioritise threats and develop effective conservation actions. Using results from aerial surveys conducted between 2009 and 2014 over the Ligurian, Corsican, Sardinian, northern and central Tyrrhenian seas (626,228 km2), this study provides the first quantitative information on giant devil ray abundance and habitat choice in the western Mediterranean. Devil rays were observed in all seasons except winter, with their estimated abundance in the study area peaking in summer. The overall uncorrected mean density in the study area during summer was estimated at 0.0257 individuals km-2 (range: 0.017–0.044), resulting in a total abundance estimate of 6,092 (12.7%CV) individuals at the surface; once corrected for availability bias, this estimate indicates a summer presence of >12,700 devil rays in the study area. Rays were mostly observed alone even if occasionally, larger aggregations up to a maximum of 18 individuals were observed. Although observed throughout the study area, spatial modelling identified their preferred habitat to be over a broad strip connecting the Tuscan Archipelago to Eastern Sardinia, over a wide range of water depths ranging from 10 to 2000m. The observed seasonal changes in giant devil ray distribution in this study, combined with similar evidence from other areas in the Mediterranean, support the hypothesis that the species undertakes latitudinal migrations across the region, taking advantage of highly productive waters in the north during summer, and warmer southern waters during winter. PMID:26580814

  8. The Devil We Don't Know: Investigating Habitat and Abundance of Endangered Giant Devil Rays in the North-Western Mediterranean Sea.

    PubMed

    Notarbartolo di Sciara, Giuseppe; Lauriano, Giancarlo; Pierantonio, Nino; Cañadas, Ana; Donovan, Greg; Panigada, Simone

    2015-01-01

    The giant devil ray Mobula mobular, the only Mediterranean mobulid, is subject to mortality caused by directed and accidental captures in fisheries throughout the region. Whilst the combination of human impacts, limited range and a low reproductive potential is not inconsistent with its endangered listing, there are insufficient data to enable a quantitative assessment of trends. Without this, it is difficult to assess and prioritise threats and develop effective conservation actions. Using results from aerial surveys conducted between 2009 and 2014 over the Ligurian, Corsican, Sardinian, northern and central Tyrrhenian seas (626,228 km2), this study provides the first quantitative information on giant devil ray abundance and habitat choice in the western Mediterranean. Devil rays were observed in all seasons except winter, with their estimated abundance in the study area peaking in summer. The overall uncorrected mean density in the study area during summer was estimated at 0.0257 individuals km-2 (range: 0.017-0.044), resulting in a total abundance estimate of 6,092 (12.7%CV) individuals at the surface; once corrected for availability bias, this estimate indicates a summer presence of >12,700 devil rays in the study area. Rays were mostly observed alone even if occasionally, larger aggregations up to a maximum of 18 individuals were observed. Although observed throughout the study area, spatial modelling identified their preferred habitat to be over a broad strip connecting the Tuscan Archipelago to Eastern Sardinia, over a wide range of water depths ranging from 10 to 2000m. The observed seasonal changes in giant devil ray distribution in this study, combined with similar evidence from other areas in the Mediterranean, support the hypothesis that the species undertakes latitudinal migrations across the region, taking advantage of highly productive waters in the north during summer, and warmer southern waters during winter. PMID:26580814

  9. Study on the location and fit of continents in western central Pangea with a focus on the Mediterranean and North Atlantic Ocean

    NASA Astrophysics Data System (ADS)

    Kwon, Ohyeok; Cheong, Hyeong-Bin

    2015-04-01

    Since Alfred Wegener proposed the theory of continental drift more than a century ago, continuous effort to reconstruct the super continent Pangea has been carried out paleo-geographically during past several decades. Although a remarkable success has been achieved, there remains still a great uncertainty on the precise location and fits of the continents that constitute the Pangea. While the fits are recognized as quite complete for Gondwana, the northern part of Pangea, the fits for Laurasia which contains North Ameraica and Eurasia, are left with a lot of improvement. What the two giant continents look like when they were fitted to form the Pangea is also a unsolved question. Several hypothesis for the fits of Laurasia and Gondwana have been raised, and the scenarios of Pangea A1, Pangea A2, Pangea B, and Pangea C were proposed hitherto. Recently, an updated version very close to Pangea A2 was suggested by authors including Van der Voo, Trond H. Torsvik, which have improved several deficiencies of the Pangea A2. However, it was found that the new scenario cannot be fully supported by the paleomagnetism data. Furthermore, it is not in complete agreement with previous paleogeological surveys on major geological features such as Variscan and Caledonian orogenic belt, indicating that a more sophisticated scenario is needed still for the Pangea. The purpose of this study is to reconstruct the continents in western central Pangea with a focus on the Mediterranean and North Atlantic Ocean. A new fit of continents to form the Pangea is proposed, where the continents are fitted with enhanced accuracy compared to other models of Pangea particularly for the Mediterranean Sea, central America, Iran Plateau etc.. The results suggest that the continents were not distorted significantly on the process of drifting and merging during the past 200 million years.

  10. 3d Operational Hydrodinamic Modelling System as a Support to Oil Spill Responses in the Ligurian Sea (North-Western Mediterranean)

    NASA Astrophysics Data System (ADS)

    Del Giudice, T.; Quagliati, M.; Bertolotto, R.; Pedroncini, A.; Cusati, L. A.

    2014-12-01

    Accidental oil spills have a significant impact on marine ecosystems reminding us the importance of an efficiency emergency planning to ensure a quick and proper response. In this phase, the numerical modelling approach emerges as a useful tool in order to simulate the scenarios and addresses the issue of oil dispersion in the case of a spill. The 3D operational hydrodynamic modelling system of the Ligurian Sea (North-Western Mediterranean) is used as a base to predict the possible oil trajectory and to track the path and fate of spilled oil under the prevailing hydrodynamic and meteorological conditions. The operative chain of the hydrodynamic model was developed by DHI Italia for the Regional Environment Protection Agency (ARPAL) operating in the Ligurian region (Italy) with the objective to preserve the environment, support the activities of the Civil Protection Department and promote a sustainable, healthy and safety management of the local resources. In this chain the MFS Mediterranean 3D model (operated within MyOcean EU Project - Copernicus Programme) was downscaled from 6.5 km to finer nearshore mesh (500 m). The increased spatial resolution allows the correct simulation of current developments in the vicinity of morphological discontinuities such as the promontory of Portofino on the Ligurian coast. The meteorological forcing is provided by MOLOCH, a LAM model operated by ARPAL together with fresh water discharges from the main rivers through hydrological modelling. Since the Ligurian Sea recently hosted the transfer of wreck Costa Concordia some real time simulations of hypothetical oil spill were performed to support the crisis unit of the Genoa Coast Guard. Simulations led to interesting results concerning the importance of updated weather conditions, which strongly influence current trends, focusing on the importance of the continuity of the modelling chain.

  11. Assessment of the coastal dynamics in a nested zoom and feedback on the boundary current: the North-Western Mediterranean Sea case

    NASA Astrophysics Data System (ADS)

    Declerck, Amandine; Ourmières, Yann; Molcard, Anne

    2016-09-01

    The Northern Current (hereafter NC), the major current in the North-Western Mediterranean (hereafter NWM) basin, has been largely investigated in the litterature for its mesoscale features. Its behaviour in the Var region can strongly condition the downstream flow along the Gulf of Lions shelf and Spain coast, making this zone a key area. However, the sub-mesoscale dynamics of the area and its potential impacts on the rest of the flow are not well known. This work reveals the potential interest of better simulating high-resolution dynamics in a restricted area and how this could improve the circulation representation in a larger area. To address this question, a very high resolution configuration (1/192∘) nested in an already existing high-resolution configuration (1/64∘) has been developed, using the NEMO model. Comparisons with observations show that the very high-resolution changes only weakly the mean NC characteristics but can significantly modify individual mesoscale events such as eddies and meanders occurring in the zoomed area. Furthermore, the coastal dynamics and episodic intrusions of a NC secondary branch inside a semi-enclosed bay appear to be significantly enhanced. In a second stage, the assessment of the feedback of this improved dynamics on the regional mesoscale dynamics is shown, this being allowed by the two-way coupling option of the embedded configuration using AGRIF.

  12. Assessment of the coastal dynamics in a nested zoom and feedback on the boundary current: the North-Western Mediterranean Sea case

    NASA Astrophysics Data System (ADS)

    Declerck, Amandine; Ourmières, Yann; Molcard, Anne

    2016-11-01

    The Northern Current (hereafter NC), the major current in the North-Western Mediterranean (hereafter NWM) basin, has been largely investigated in the litterature for its mesoscale features. Its behaviour in the Var region can strongly condition the downstream flow along the Gulf of Lions shelf and Spain coast, making this zone a key area. However, the sub-mesoscale dynamics of the area and its potential impacts on the rest of the flow are not well known. This work reveals the potential interest of better simulating high-resolution dynamics in a restricted area and how this could improve the circulation representation in a larger area. To address this question, a very high resolution configuration (1/192∘) nested in an already existing high-resolution configuration (1/64∘) has been developed, using the NEMO model. Comparisons with observations show that the very high-resolution changes only weakly the mean NC characteristics but can significantly modify individual mesoscale events such as eddies and meanders occurring in the zoomed area. Furthermore, the coastal dynamics and episodic intrusions of a NC secondary branch inside a semi-enclosed bay appear to be significantly enhanced. In a second stage, the assessment of the feedback of this improved dynamics on the regional mesoscale dynamics is shown, this being allowed by the two-way coupling option of the embedded configuration using AGRIF.

  13. Variability of slope current positioning from space: Application to the Northern Current in the North Western Mediterranean Sea

    NASA Astrophysics Data System (ADS)

    Bouffard, Jerome; Marmain, Julien; Bosse, Anthony; Petrenko, Anne; Forget, Philippe; Doglioli, Andrea; Testor, Pierre; Mortier, Laurent

    The space-time variability of slope currents plays a key role on the across-shore transport of natural and anthropogenic elements. It is therefore of critical importance to monitor the front positioning associated with these hydrodynamical features in a synoptic way, in particular along densely populated coasts such as the littoral zone of the Mediterranean Sea. Our paper proposes to address this issue by developing a new multi-satellite altimetric-based approach aiming at monitoring the long-term behaviour of the Northern Current, from 2002 to 2012. Our method is assessed by direct comparisons with observations from glider transects of the current, coastal HF radar and a moored current-meter. Despite important limitations due to the current altimetric sampling and a lower accuracy in the 50 km coastal band, we demonstrate the ability of our new method to characterize the variability of the front positioning from intra-seasonal to annual scales. We particularly focus the analysis on the Gulf of Lion, where the distance between the mean geostrophic flow and the coast allows a good detection of high frequency signals associated with slope current intrusions over the continental shelf. We show that such abrupt events generally occur in autumn and are forced by heterogeneous, strong and rapidly evolving south-easterly wind events. This work is based on an original exploitation of the existing along-track altimetry data and paves the way for new applications within the prospect of the next satellite generation whose technology is more suitable for coastal studies.

  14. The low frequency Western Mediterranean summer variability: relevance, feedbacks and predictability.

    NASA Astrophysics Data System (ADS)

    Jose, Ortizbevia Maria; Antonio, Ruizdeelvira; Francisco Jose, Alvarez-Garcia; Miguel, Tasambay-Salazar

    2016-04-01

    In a recent study, OrtizBeviá et al. (2012) have defined a seasonal index, the Western Mediterranean Index, in order to characterize the Western Mediterranean summer variability. They have found there a statistically significant feedback between the Mediterranean and the North Pacific variability, characterized by the Pacific North America Mode Index. They have detected also a feedback between the Western Mediterranean in summer and the variability of some areas of the North Atlantic basin. Based on these statistical linear relationship they proposed a model to forecast the part of the Western Mediterranean variability represented by the Western Mediterranean Index in summer and autumn and validate it through some hindcast experiments, with a moderate, but significant skill. OrtizBeviá et al.(2012) presented also the evidence of the existence of a low frequency, multidecadal component in the Western Mediterranean summer variability. In the work to be presented here we extend the previous one, focusing on the long term variability. We perform similar statistical analysis on selected data fields that span more than 100 years. We add a second index to the characterisation of the Western Mediterranean variability and are then able to show the relevance of the Western Mediterranean summer variability for european air temperature and precipitation seasonal anomalies. Our analyses show that the variability represented by two North Atlantic Indexes play a key role in the Western Mediterranean summer variability. They also proof the existence of a feedback between this variability and that of the Pacific North America Mode, for an extended period of more than 140 years. The performance of the different predictive models built on the basis of those linear relationships are tested in a series of hindcast experiments. References Ortiz Beviá, M. J.; Alvarez García

  15. Benthic fluxes of oxygen and nutrients in sublittoral fine sands in a north-western Mediterranean coastal area

    NASA Astrophysics Data System (ADS)

    Sospedra, J.; Falco, S.; Morata, T.; Gadea, I.; Rodilla, M.

    2015-04-01

    Traditionally, benthic metabolism in sublittoral permeable sands have not been widely studied, although these sands can have a direct and transcendental impact in coastal ecosystems. This study aims to determine oxygen and nutrient fluxes at the sediment-water interface and the study of possible interactions among environmental variables and the benthic metabolism in well-sorted fine sands. Eight sampling campaigns were carried out over the annual cycle in the eastern coast of Spain (NW Mediterranean) at 9 m depth station with permeable bottoms. Water column and sediment samples were collected in order to determine physico-chemical and biological variables. Moreover, in situ incubations were performed to estimate the exchange of dissolved solutes in the sediment-water interface using dark and light benthic chambers. Biochemical compounds at the sediment surface ranged between 160 and 744 μg g-1 for proteins, 296 and 702 μg g-1 for carbohydrates, and between 327 and 1224 μg C g-1 for biopolymeric carbon. Chloroplastic pigment equivalents in sediments were mainly composed by chlorophyll a (1.81-2.89 μg g-1). These sedimentary organic descriptors indicated oligotrophic conditions according to the biochemical approach used. In this sense, the most abundant species in the macrobenthic community were sensitive to organic enrichment. In dark conditions, benthic fluxes behaved as a sink of oxygen and a source of nutrients. Oxygen fluxes (between -26,610 and -10,635 μmol m-2 d-1) were related with labile organic fraction (r=-0.86, p<0.01 with biopolymeric carbon; r=-0.91, p<0.01 with chloroplastic pigment equivalents). Daily fluxes of dissolved oxygen, that were obtained by adding light and dark fluxes, were only positive in spring campaigns (6966 μmol m-2 d-1) owing to the highest incident irradiance levels (r=0.98, p<0.01) that stimulate microphytobenthic primary production. Microphytobenthos played an important role on benthic metabolism and was the main primary

  16. Methyl mercury distributions in relation to the presence of nano- and picophytoplankton in an oceanic water column (Ligurian Sea, North-western Mediterranean)

    NASA Astrophysics Data System (ADS)

    Heimbürger, Lars-Eric; Cossa, Daniel; Marty, Jean-Claude; Migon, Christophe; Averty, Bernard; Dufour, Aurélie; Ras, Josephine

    2010-10-01

    Recent findings on the distribution of methylated mercury (MeHg T) in waters have highlighted the importance of organic carbon remineralization on the production of these compounds in the open ocean. Here, we present the first time-series (20 monthly samplings between July 2007 and May 2009) of high-resolution vertical profiles (10-12 depths in a 2350 m water column) of MeHg T distributions in an open ocean environment, the Ligurian Sea (North-western Mediterranean Sea). Concentrations varied within the sub-picomolar range (general mean: 0.30 ± 0.17 pmol L -1, n = 214) with the lowest values at the surface, increasing with depth up to the oxygen minimum zone, and decreasing slowly at greater depth. Concentrations in the surface waters never exceeded 0.15 pmol L -1, while the highest concentrations (up to 0.82 pmol L -1) were associated to the hypoxycline during the autumn bloom. A detailed vertical MeHg T profile reveals a "double-peak" pattern, coincidental with the two microbial layers described by Tanaka and Rassoulzadegan (2002), the so-called "microbial food web" in the euphotic zone (<100 m) and the "microbial loop" in the aphotic zone (>100 m). Temporal variations in the MeHg T abundance and distribution in the water column were linked to seasonality. The highest MeHg T concentrations were found in the oxygen minimum zone during the period of stratification, and coincide with the greatest abundance of nano- and picophytoplankton (cyanobacteria, nanoflagellates, etc.) in the euphotic layer. None of our deep MeHg T measurements (˜100 m above the sea bottom) revealed a significant sedimentary source of MeHg T. We explored the correlation between MeHg T concentrations and the apparent oxygen utilization, a proxy of organic matter remineralization, over the study period. Results of this study strengthen the hypothesis that net mercury methylation in the open ocean occurs in the water column, is linked to organic matter regeneration, and is promoted by the

  17. Survey of submesoscale structures at the margin of the Northern Current in the North Western Mediterranean Sea using Gliders: observations and diagnostics

    NASA Astrophysics Data System (ADS)

    Bosse, Anthony; Testor, Pierre; Mortier, Laurent; Beguery, Laurent; Bernardet, Karim; Taillandier, Vincent; d'Ortenzio, Fabrizio; Prieur, Louis; Coppola, Laurent; Bourrin, François

    2013-04-01

    From 2008 on, repeated sections crossing the Northern Current (NC) were operated by gliders as part of a global observing system (MOOSE project) of the North Western Mediterranean Sea. This work is dedicated to the analysis of the submesoscale thermohaline variability at the margin of this current observed by gliders. The mean circulation of the basin is characterized by a cyclonic gyre (whose Northern part is the so-called NC) associated with a doming of the isopycnals preconditionning the whole interior basin to great vertical mixing. The thermal and haline differences between the Atlantic Water (AW) transported by the NC and older and modified AW off the coast leads to a frontal structure. Especially in winter, when the mixed layer depth used to reach several hundreds of meters offshore, isopycnal outcropping and the role of frontal processes are enhanced leading to intense variability at scales smaller than the deformation radius. Based on diagnostics using the Potential Vorticity (PV) computed from the glider data assuming quasi-geostrophic conditions and no variation in the alongshore direction, we discuss the dynamical processes at work, with a focus on 2 typical examples: (1) the first example takes place in winter during a strong vertical mixing event. While the glider crossed the frontal region, the temperature and salinity fields exhibit vertical motions at depths about 0-400m. Frontogenesis might be at play through mesoscale strain since the glider shows an intense mesoscale activity but a weak stratification and enhanced horizontal buoyancy gradient actually make the Ertel PV reach negative values and symmetric instability is likely to be a prominent mechanism explaining the observed variability. (2) the second example takes place in spring. We identify an episode of down-front wind blowing during the glider deployment which could have extracted PV from the surface layer. However, the geostrophic turbulence is in that case likely to play a key role in

  18. Abrupt climate shift in the Western Mediterranean Sea

    PubMed Central

    Schroeder, K.; Chiggiato, J.; Bryden, H. L.; Borghini, M.; Ben Ismail, S.

    2016-01-01

    One century of oceanographic measurements has evidenced gradual increases in temperature and salinity of western Mediterranean water masses, even though the vertical stratification has basically remained unchanged. Starting in 2005, the basic structure of the intermediate and deep layers abruptly changed. We report here evidence of reinforced thermohaline variability in the deep western basin with significant dense water formation events producing large amounts of warmer, saltier and denser water masses than ever before. We provide a detailed chronological order to these changes, giving an overview of the new water masses and following their route from the central basin interior to the east (toward the Tyrrhenian) and toward the Atlantic Ocean. As a consequence of this climate shift, new deep waters outflowing through Gibraltar will impact the North Atlantic in terms of salt and heat input. In addition, modifications in the Mediterranean abyssal ecosystems and biogeochemical cycles are to be expected. PMID:26965790

  19. Abrupt climate shift in the Western Mediterranean Sea.

    PubMed

    Schroeder, K; Chiggiato, J; Bryden, H L; Borghini, M; Ben Ismail, S

    2016-01-01

    One century of oceanographic measurements has evidenced gradual increases in temperature and salinity of western Mediterranean water masses, even though the vertical stratification has basically remained unchanged. Starting in 2005, the basic structure of the intermediate and deep layers abruptly changed. We report here evidence of reinforced thermohaline variability in the deep western basin with significant dense water formation events producing large amounts of warmer, saltier and denser water masses than ever before. We provide a detailed chronological order to these changes, giving an overview of the new water masses and following their route from the central basin interior to the east (toward the Tyrrhenian) and toward the Atlantic Ocean. As a consequence of this climate shift, new deep waters outflowing through Gibraltar will impact the North Atlantic in terms of salt and heat input. In addition, modifications in the Mediterranean abyssal ecosystems and biogeochemical cycles are to be expected. PMID:26965790

  20. Abrupt climate shift in the Western Mediterranean Sea

    NASA Astrophysics Data System (ADS)

    Schroeder, K.; Chiggiato, J.; Bryden, H. L.; Borghini, M.; Ben Ismail, S.

    2016-03-01

    One century of oceanographic measurements has evidenced gradual increases in temperature and salinity of western Mediterranean water masses, even though the vertical stratification has basically remained unchanged. Starting in 2005, the basic structure of the intermediate and deep layers abruptly changed. We report here evidence of reinforced thermohaline variability in the deep western basin with significant dense water formation events producing large amounts of warmer, saltier and denser water masses than ever before. We provide a detailed chronological order to these changes, giving an overview of the new water masses and following their route from the central basin interior to the east (toward the Tyrrhenian) and toward the Atlantic Ocean. As a consequence of this climate shift, new deep waters outflowing through Gibraltar will impact the North Atlantic in terms of salt and heat input. In addition, modifications in the Mediterranean abyssal ecosystems and biogeochemical cycles are to be expected.

  1. The effect of breakwaters on the structure of marine soft-bottom assemblages: a case study from a North-Western Mediterranean basin.

    PubMed

    Becchi, Claudia; Ortolani, Irene; Muir, Alexander; Cannicci, Stefano

    2014-10-15

    This two-year study is the first attempt to analyse the ecological effects of breakwater systems on soft-bottom assemblages along the North Tyrrhenian coast. Differently from previous studies focusing on infauna of on-shore and off-shore sides, we compared the assemblages inhabiting the surrounding soft-bottoms not directly protected by the breakwaters, defining our sampling stations at varying distances from the breakwaters and at constant distance from the coast. Data collected revealed that abundance, species richness and M-AMBI ecological quality differed between northern and southern sides, and were related to distance from structures. Multivariate analyses of relationships between assemblages and abiotic characteristics support this hypothesis. The extension of these effects, that resulted to be weak and limited to a restricted area, could be a consequence of coastal current on local hydrodynamics. This study provides novel and critical information for the management of the coastal defence infrastructure spreading along the western coast of Italy. PMID:25152186

  2. Enteric fever in Mediterranean north Africa.

    PubMed

    Ghenghesh, Khalifa Sifaw; Franka, Ezzedin; Tawil, Khaled; Wasfy, Momtaz O; Ahmed, Salwa F; Rubino, Salvatore; Klena, John D

    2009-01-01

    Typhoid fever is endemic in the Mediterranean North African countries (Morocco, Algeria, Tunisia, Libya, and Egypt) with an estimated incidence of 10-100 cases per 100,000 persons. Outbreaks caused by Salmonella enterica serovar Typhi are common and mainly due to the consumption of untreated or sewage-contaminated water. Salmonella enterica Paratyphi B is more commonly involved in nosocomial cases of enteric fever in North Africa than expected and leads to high mortality rates among infants with congenital anomalies. Prevalence among travellers returning from this region is low, with an estimate of less than one per 100,000. Although multidrug resistant strains of Salmonella Typhi and Paratyphi are prevalent in this region, the re-emergence of chloramphenicol- and ampicillin-susceptible strains has been observed. In order to better understand the epidemiology of enteric fever in the Mediterranean North African region, population-based studies are needed. These will assist the health authorities in the region in preventing and controlling this important disease.

  3. Towards an impact assessment of bauxite red mud waste on the knowledge of the structure and functions of bathyal ecosystems: The example of the Cassidaigne canyon (north-western Mediterranean Sea).

    PubMed

    Dauvin, Jean-Claude

    2010-02-01

    Since 1967, the alumina plants in the Marseilles area (Barasse and Gardanne) have been discharging the mineral residue (i.e., red mud) resulting from the alkaline processing of bauxite into the submarine Cassidaigne canyon (north-western Mediterranean Sea) through pipes situated at 320-330 m in depth. The Barasse pipe stopped being used in 1988. From 1987 to 1996, many decrees and regulations were promulgated by the French State to rule the conditions under which the Gardanne alumina refinery was authorized to dispose of the bauxite residue in the sea. The refinery was required: (i) to study the hydrodynamic circulation in the Cassidaigne canyon to evaluate the potential dispersion and transport of fine elements discharged into the water mass and their impact on the pelagic ecosystem; (ii) to survey the marine environment every five years to control the expansion and thickness of the red mud deposit and compare the evolution of the benthic macrofauna at representative sampling sites in the environment affected by the red mud discharge with that of reference sites outside of the red mud plume; (iii) to study the effect of the discharge on fishing activities; and (iv) to investigate the toxicity of the red mud, particularly its persistence, accumulation, interaction and effect on the marine ecosystem, paying special attention to the bio-accumulation of chromium and vanadium. A Scientific Committee was created to insure an independent evaluation of the studies promised by the manufacturer in response to the State's regulations. Since the beginning of the 1960s, data have been accumulating on the structure and long-term functioning of the Cassidaigne bathyal ecosystem. This paper presents the collaborative efforts of the State-Manufacturer-Committee triplet and summarizes the main results obtained during the last period's sea campaigns (1991-2007). This paper also illustrates how national regulations concerning manufacturers, such as Gardanne alumina refinery, have

  4. Detection of Saharan dust and biomass burning events using near-real-time intensive aerosol optical properties in the north-western Mediterranean

    NASA Astrophysics Data System (ADS)

    Ealo, Marina; Alastuey, Andrés; Ripoll, Anna; Pérez, Noemí; Cruz Minguillón, María; Querol, Xavier; Pandolfi, Marco

    2016-10-01

    The study of Saharan dust events (SDEs) and biomass burning (BB) emissions are both topics of great scientific interest since they are frequent and important polluting scenarios affecting air quality and climate. The main aim of this work is evaluating the feasibility of using near-real-time in situ aerosol optical measurements for the detection of these atmospheric events in the western Mediterranean Basin (WMB). With this aim, intensive aerosol optical properties (SAE: scattering Ångström exponent, AAE: absorption Ångström exponent, SSAAE: single scattering albedo Ångström exponent and g: asymmetry parameter) were derived from multi-wavelength aerosol light scattering, hemispheric backscattering and absorption measurements performed at regional (Montseny; MSY, 720 m a.s.l.) and continental (Montsec; MSA, 1570 m a.s.l.) background sites in the WMB. A sensitivity study aiming at calibrating the measured intensive optical properties for SDEs and BB detection is presented and discussed. The detection of SDEs by means of the SSAAE parameter and Ångström matrix (made up by SAE and AAE) depended on the altitude of the measurement station and on SDE intensity. At MSA (mountain-top site) SSAAE detected around 85 % of SDEs compared with 50 % at the MSY station, where pollution episodes dominated by fine anthropogenic particles frequently masked the effect of mineral dust on optical properties during less intense SDEs. Furthermore, an interesting feature of SSAAE was its capability to detect the presence of mineral dust after the end of SDEs. Thus, resuspension processes driven by summer regional atmospheric circulations and dry conditions after SDEs favoured the accumulation of mineral dust at regional level having important consequences for air quality. On average, SAE, AAE and g ranged between -0.7 and 1, 1.3 and 2.5 and 0.5 and 0.75 respectively during SDEs. Based on the aethalometer model, BB contribution to equivalent black carbon (BC) accounted for 36 and 40

  5. Unexpected abundance and long-term relative stability of the brown alga Cystoseira amentacea, hitherto regarded as a threatened species, in the north-western Mediterranean Sea.

    PubMed

    Thibaut, Thierry; Blanfuné, Aurélie; Markovic, Laurent; Verlaque, Marc; Boudouresque, Charles F; Perret-Boudouresque, Michèle; Maćic, Vesna; Bottin, Lorraine

    2014-12-15

    Cystoseira amentacea is a Mediterranean endemic alga thriving on very shallow rocky substrates. It has been considered as a threatened species, having experienced a steady decline and is therefore protected by international conventions. The historical distribution of the species has been assessed along the French Mediterranean coast, on the basis of 467 articles and herbarium vouchers. We have produced an accurate map of its current distribution and abundance along 1832 km of coastline, through in situ surveys. C. amentacea was observed along 1125 km of shoreline, including 33% of almost continuous or continuous belt. In most of its range, there is no evidence of loss, except in 4 areas of Provence, French Riviera and Corsica. A significant relation was found between the absence or low abundance of C. amentacea and the vicinity of ports and large sewage outfalls. The status of conservation of the species should therefore be reassessed. PMID:25440190

  6. Unexpected abundance and long-term relative stability of the brown alga Cystoseira amentacea, hitherto regarded as a threatened species, in the north-western Mediterranean Sea.

    PubMed

    Thibaut, Thierry; Blanfuné, Aurélie; Markovic, Laurent; Verlaque, Marc; Boudouresque, Charles F; Perret-Boudouresque, Michèle; Maćic, Vesna; Bottin, Lorraine

    2014-12-15

    Cystoseira amentacea is a Mediterranean endemic alga thriving on very shallow rocky substrates. It has been considered as a threatened species, having experienced a steady decline and is therefore protected by international conventions. The historical distribution of the species has been assessed along the French Mediterranean coast, on the basis of 467 articles and herbarium vouchers. We have produced an accurate map of its current distribution and abundance along 1832 km of coastline, through in situ surveys. C. amentacea was observed along 1125 km of shoreline, including 33% of almost continuous or continuous belt. In most of its range, there is no evidence of loss, except in 4 areas of Provence, French Riviera and Corsica. A significant relation was found between the absence or low abundance of C. amentacea and the vicinity of ports and large sewage outfalls. The status of conservation of the species should therefore be reassessed.

  7. Bacteria as part of bioluminescence emission at the deep ANTARES station (North-Western Mediterranean Sea) during a one-year survey

    NASA Astrophysics Data System (ADS)

    Martini, S.; Michotey, V.; Casalot, L.; Bonin, P.; Guasco, S.; Garel, M.; Tamburini, C.

    2016-10-01

    Bioluminescent bacteria have been studied during a one-year survey in 2011 at the deep ANTARES site (Northwestern Mediterranean Sea, 2000 m depth). The neutrino underwater telescope ANTARES, located at this station, has been used to record the bioluminescence at the same depth. Together with these data, environmental variables (potential temperature, salinity, nutrients, dissolved organic carbon and oxygen) have been characterized in water samples. The year 2011 was characterized by relatively stable conditions, as revealed by minor variability in the monitored oceanographic variables, by low bioluminescence and low current speed. This suggests weak eukaryote participation and mainly non-stimulated light emission. Hence, no processes of dense water have affected the ANTARES station during this survey. Abundance of bioluminescent bacteria belonging to Photobacterium genus, measured by qPCR of the luxF gene, ranged from 1.4×102 to 7.2×102 genes mL-1. Their effective activity was confirmed through mRNA luxF quantification. Our results reveal that bioluminescent bacteria appeared more active than the total counterpart of bacteria, suggesting an ecological benefit of this feature such as favoring interaction with macro-organisms. Moreover, these results show that part of the bioluminescence, recorded at 2000 m depth over one year, could be due to bioluminescent bacteria in stable hydrological conditions.

  8. Long-term decline of the populations of Fucales (Cystoseira spp. and Sargassum spp.) in the Albères coast (France, North-western Mediterranean).

    PubMed

    Thibaut, Thierry; Pinedo, Susana; Torras, Xavier; Ballesteros, Enric

    2005-12-01

    Only five of fourteen species of Fucales reported at the end of the XIXth century are currently present in the Albères Coast (France, NW Mediterranean). According to historical data there has been a steady decrease of all the populations since the 1940s. Seven taxa now extinct (Cystoseira crinita, Cystoseira barbata, Cystoseira foeniculacea f. tenuiramosa, Cystoseira spinosa, Cystoseira spinosa var. compressa, Sargassum hornschuchii and Sargassum vulgare) were considered frequent and some of them were the dominant and engineering species in several phytobenthic assemblages. Moreover, only one of the five species left, shows no signs of regression (Cystoseira compressa), two are considered as rare (Cystoseira caespitosa, Cystoseira zosteroides), and one is very rare (Cystoseira elegans). Cystoseira mediterranea, a species that was reported to make a continuous belt along the shores of the Albères coast, has almost disappeared from some areas. Overgrazing by sea urchins, outcompetition by mussels, habitat destruction, scientific research sampling and, probably, human trampling and chemical pollution are to be blamed for the decline of populations thriving in shallow waters. Deep-water species have been affected by an increase in water turbidity and, probably, chemical pollution and direct plant destruction attributed to net fishing. If degradation of the environmental conditions continues, the remaining Cystoseira species will face a most unwelcome prospect. Even after the removal of the causes that led to its die-off, natural restoration of extinct species seems not to be possible because the decline has also affected populations from nearby areas and zygotes are unable to disperse over long distances. Urgent management actions have to be designed in order to improve the current situation of the populations of Fucales in the Albères coast.

  9. Long-term decline of the populations of Fucales (Cystoseira spp. and Sargassum spp.) in the Albères coast (France, North-western Mediterranean).

    PubMed

    Thibaut, Thierry; Pinedo, Susana; Torras, Xavier; Ballesteros, Enric

    2005-12-01

    Only five of fourteen species of Fucales reported at the end of the XIXth century are currently present in the Albères Coast (France, NW Mediterranean). According to historical data there has been a steady decrease of all the populations since the 1940s. Seven taxa now extinct (Cystoseira crinita, Cystoseira barbata, Cystoseira foeniculacea f. tenuiramosa, Cystoseira spinosa, Cystoseira spinosa var. compressa, Sargassum hornschuchii and Sargassum vulgare) were considered frequent and some of them were the dominant and engineering species in several phytobenthic assemblages. Moreover, only one of the five species left, shows no signs of regression (Cystoseira compressa), two are considered as rare (Cystoseira caespitosa, Cystoseira zosteroides), and one is very rare (Cystoseira elegans). Cystoseira mediterranea, a species that was reported to make a continuous belt along the shores of the Albères coast, has almost disappeared from some areas. Overgrazing by sea urchins, outcompetition by mussels, habitat destruction, scientific research sampling and, probably, human trampling and chemical pollution are to be blamed for the decline of populations thriving in shallow waters. Deep-water species have been affected by an increase in water turbidity and, probably, chemical pollution and direct plant destruction attributed to net fishing. If degradation of the environmental conditions continues, the remaining Cystoseira species will face a most unwelcome prospect. Even after the removal of the causes that led to its die-off, natural restoration of extinct species seems not to be possible because the decline has also affected populations from nearby areas and zygotes are unable to disperse over long distances. Urgent management actions have to be designed in order to improve the current situation of the populations of Fucales in the Albères coast. PMID:16026805

  10. Modelling for anchovy recruitment studies in the Gulf of Lions (Western Mediterranean Sea)

    NASA Astrophysics Data System (ADS)

    Nicolle, Amandine; Garreau, Pierre; Liorzou, Bernard

    2009-12-01

    Anchovy ( Engraulis encrasicolus) is an important commercial species and one of the most abundant pelagic fish in the Gulf of Lions and the Catalan Sea. The factors influencing its recruitment are crucial to fisheries and ecological research. Among those factors transport of larvae by hydrodynamics (currents) is important because it determines whether the organisms can reach areas favourable to recruitment or are dispersed. Therefore, the first step in anchovy recruitment modelling is to simulate North-western Mediterranean Sea circulation. Several years (2001-2008) of hydrodynamics were simulated with the MARS-3D code. The resulting simulated currents and salinity are used by Lagrangian tool, Ichthyop, to transport anchovy eggs and larvae to the Western Mediterranean Sea. The aim of this study is to understand the main hydrodynamic processes that control anchovy transport and the effects of diel vertical migration on the transport and final distribution of anchovy.

  11. Per- and polyfluoroalkyl substances in the Western Mediterranean Sea waters.

    PubMed

    Brumovský, Miroslav; Karásková, Pavlína; Borghini, Mireno; Nizzetto, Luca

    2016-09-01

    The spatial and temporal distribution of per- and polyfluoroalkyl substances (PFASs) in the open Western Mediterranean Sea waters was investigated in this study for the first time. In addition to surface water samples, a deep water sample (1390 m depth) collected in the center of the western basin was analyzed. Perfluorohexanoic acid (PFHxA), perfluoroheptanoic acid (PFHpA), perfluorooctanoic acid (PFOA), perfluorohexanesulfonate (PFHxS) and perfluorooctanesulfonate (PFOS) were detected in all samples and were the dominant PFASs found. The sum of PFAS concentrations (ΣPFASs) ranged 246-515 pg/L for surface water samples. PFASs in surface water had a relatively homogeneous distribution with levels similar to those previously measured in the Atlantic near the Strait of Gibraltar, in water masses feeding the inflow to the Mediterranean Sea. Higher concentrations of PFHxA, PFHpA and PFHxS were, however, found in the present study. Inflowing Atlantic water and river/coastal discharges are likely the major sources of PFASs to the Western Mediterranean basin. Slightly lower (factor of 2) ΣPFASs was found in the deep water sample (141 pg/L). Such a relatively high contamination of deep water is likely to be linked to recurring deep water renewal fed by downwelling events in the Gulf of Lion and/or Ligurian Sea. PMID:27314632

  12. Atmospheric patterns driving Holocene productivity in the Alboran Sea (Western Mediterranean): a multiproxy approach.

    NASA Astrophysics Data System (ADS)

    Ausin, Blanca; Flores, Jose-Abel; Sierro, Francisco Javier; Cacho, Isabel; Hernández-Almeida, Iván; Martrat, Belén; Grimalt, Joan

    2014-05-01

    This study is aimed to reconstruct productivity during the Holocene in the Western Mediterranean as well as to investigate what processes account for its short-term variability. Fossil coccolithophore assemblages have been studied along with Mg/Ca and Uk'37-estimated Sea Surface Temperature (SST) and other paleoenvironmental proxies. The study site is located in a semi-permanent area of upwelling in the Alboran Sea. This productive cell is of special interest since is closely related to local hydrological dynamics driven by the entering Atlantic Jet (AJ). The onset of this productive cell is suggested at 7.7 ka cal. B.P. and linked to the establishment of the anticyclonic gyres. From 7.7 ka cal. BP to present, the N ratio and accumulation rate of Florisphaera profunda show successive upwelling and stratification events. This alternation is simultaneous to changes in the Western Mediterranean Deep Water (WMDW) formation rate in the Gulf of Lions [Frigola et al., 2007], along with changes in Mg/Ca-estimated SST, relative abundance of reworked nannoliths, pollen grains record [Fletcher et al., 2012] and n-hexacosan-1-ol index. Two scenarios are proposed to explain short-term climatic and oceanographic variability: [1] Wetter climate and weaker north-westerlies blowing over the Gulf of Lions trigger a slackening of the WMDW formation. Consequently, a minor AJ inflows the Alboran Sea leading to less vertical mixing and a deepening of the nutricline and hence, long-term stratification events. [2] Arid climate and stronger north-westerlies enable WMDW reinforcement. In turn, increased AJ triggers vertical mixing and nutricline shoaling, and therefore, productive periods. Finally, changes in atmospheric patterns (e.g. the winter North Atlantic Oscillation; [Olsen et al., 2012]) prove to be useful in explaining the WMDW formation in the Gulf of Lions and associated short-term productivity variations in the Alboran Sea. References Fletcher, W. J., M. Debret, and M. F

  13. The last glacial-interglacial transition and dinoflagellate cysts in the western Mediterranean Sea

    NASA Astrophysics Data System (ADS)

    Rouis-Zargouni, Imene; Turon, Jean-Louis; Londeix, Laurent; Kallel, Néjib; Essallami, Latifa

    2012-02-01

    Using the analysis of dinoflagellate cysts in three deep-sea sediments cores situated in the Sicilian-Tunisian Strait, in the Gulf of Lions and in the Alboran Sea, we reconstruct the paleoenvironmental changes that took place during the last glacial-interglacial transition in the western Mediterranean Sea. The development of the warm microflora Impagidinium aculeatum and especially Spiniferites mirabilis appears to be an important proxy for recognizing warm periods as the Bölling/Alleröd and the Early Holocene. Bitectatodinium tepikiense, Spiniferites elongatus and Nematosphaeropsis labyrinthus mark the end of the Heinrich event 1 and the Younger Dryas. This cold microfloral association confirms the drastic climate changes in the western Mediterranean Sea synchronous to the dry and cold climate which occurred in the South European margin. The dinocyst N. labyrinthus shows high percentages in all studied regions during the Younger Dryas. Its distribution reveals a significant increase from the South to the North of this basin during this cold brief event. Thus, we note that this species can be considered as a new eco-stratigraphical tracer of the Younger Dryas in the western Mediterranean Sea.

  14. Implementation and Challenges of the Tsunami Warning System in the Western Mediterranean

    NASA Astrophysics Data System (ADS)

    Schindelé, F.; Gailler, A.; Hébert, H.; Loevenbruck, A.; Gutierrez, E.; Monnier, A.; Roudil, P.; Reymond, D.; Rivera, L.

    2015-03-01

    The French Tsunami Warning Center (CENALT) has been in operation since 2012. It is contributing to the North-eastern and Mediterranean (NEAM) tsunami warning and mitigation system coordinated by the United Nations Educational, Scientific, and Cultural Organization, and benefits from data exchange with several foreign institutes. This center is supported by the French Government and provides French civil-protection authorities and member states of the NEAM region with relevant messages for assessing potential tsunami risk when an earthquake has occurred in the Western Mediterranean sea or the Northeastern Atlantic Ocean. To achieve its objectives, CENALT has developed a series of innovative techniques based on recent research results in seismology for early tsunami warning, monitoring of sea level variations and detection capability, and effective numerical computation of ongoing tsunamis.

  15. Inconsistencies in coastal dune genesis and development in the western Mediterranean Cabopino Dune system, southern Spain

    NASA Astrophysics Data System (ADS)

    Guisado-Pintado, Emilia; Malvárez, Gonzalo; Jackson, Derek; Navas, Fatima

    2016-04-01

    It is generally agreed that a falling sea level regime is required in the long term to establish dunes as distinctive landform features along a coast. Sedimentary (supply) bodies from fluvial, glacial sources or marine platform processes also need to be in place. In most Atlantic-facing coastal dune systems the current morpho-sedimentary structures are usually associated with the period between 18K BP and present when both glacial and riverine sediments emplaced sediments within the active zone of present sea level to help form beaches and dunes. Mediterranean coastal dunes fronted by steep continental shelves, such as in the western Mediterranean coast of southern Spain are, however, not associated with glacial deposits and thus are only present in association with river mouths and/or coastal lagoons. Their development is attributed to very recent sediment supply, which, combined with other forcing factors such as wind and waves, several orders of magnitude below those of north Atlantic systems, explains their limited extent. Some coastal dune fields however, do not seem to respond to this general pattern because of their scale and, more importantly, their origin linked possibly to marine platform processes rather than riverine or lagoonal development. Here, we examine the Cabopino dune system in southern Spain offering a conceptual model of their genesis and development as an "Atlantic" dune system within a Mediterranean setting. This is demonstrated by their scale (the largest in the Spanish Mediterranean) and their morphodynamic link to nearshore and platform processes in the last 18,000 years.

  16. Food-web traits of the North Aegean Sea ecosystem (Eastern Mediterranean) and comparison with other Mediterranean ecosystems

    NASA Astrophysics Data System (ADS)

    Tsagarakis, K.; Coll, M.; Giannoulaki, M.; Somarakis, S.; Papaconstantinou, C.; Machias, A.

    2010-06-01

    A mass-balance trophic model was built to describe the food-web traits of the North Aegean Sea (Strymonikos Gulf and Thracian Sea, Greece, Eastern Mediterranean) during the mid-2000s and to explore the impacts of fishing. This is the first food-web model representing the Aegean Sea, and results were presented and discussed in comparison to other previous ecosystems modelled from the western and the central areas of the basin (South Catalan and North-Central Adriatic Seas). Forty functional groups were defined, covering the entire trophic spectrum from lower to higher trophic levels. Emphasis was placed on commercial invertebrates and fish. The potential ecological role of the invasive ctenophore, Mnemiopsis leidyi, and several vulnerable groups (e.g., dolphins) was also explored. Results confirmed the spatial productivity patterns known for the Mediterranean Sea showing, for example, that the total biomass is highest in N.C. Adriatic and lowest in N. Aegean Sea. Accordingly, food-web flows and several ecosystem indicators like the mean transfer efficiency were influenced by these patterns. Nevertheless, all three systems shared some common features evidencing similarities of Mediterranean Sea ecosystems such as dominance of the pelagic fraction in terms of flows and strong benthic-pelagic coupling of zooplankton and benthic invertebrates through detritus. The importance of detritus highlighted the role of the microbial food-web, which was indirectly considered through detritus dynamics. Ciliates, mesozooplankton and several benthic invertebrate groups were shown as important elements of the ecosystem linking primary producers and detritus with higher trophic levels in the N. Aegean Sea. Adult anchovy was shown as the most important fish group in terms of production, consumption and overall effect on the rest of the ecological groups in the model, in line with results from the Western Mediterranean Sea. The five fishing fleets considered (both artisanal and

  17. Interannual differences for sea turtles bycatch in Spanish longliners from Western Mediterranean Sea.

    PubMed

    Báez, José C; Macías, David; García-Barcelona, Salvador; Real, Raimundo

    2014-01-01

    Recent studies showed that regional abundance of loggerhead and leatherback turtles could oscillate interannually according to oceanographic and climatic conditions. The Western Mediterranean is an important fishing area for the Spanish drifting longline fleet, which mainly targets swordfish, bluefin tuna, and albacore. Due to the spatial overlapping in fishing activity and turtle distribution, there is an increasing sea turtle conservation concern. The main goal of this study is to analyse the interannual bycatch of loggerhead and leatherback turtles by the Spanish Mediterranean longline fishery and to test the relationship between the total turtle by-catch of this fishery and the North Atlantic Oscillation (NAO). During the 14 years covered in this study, the number of sea turtle bycatches was 3,940 loggerhead turtles and 8 leatherback turtles, 0.499 loggerhead turtles/1000 hooks and 0.001014 leatherback turtles/1000 hooks. In the case of the loggerhead turtle the positive phase of the NAO favours an increase of loggerhead turtles in the Western Mediterranean Sea. However, in the case of leatherback turtle the negative phase of the NAO favours the presence of leatherback turtle. This contraposition could be related to the different ecophysiological response of both species during their migration cycle.

  18. Interannual differences for sea turtles bycatch in Spanish longliners from Western Mediterranean Sea.

    PubMed

    Báez, José C; Macías, David; García-Barcelona, Salvador; Real, Raimundo

    2014-01-01

    Recent studies showed that regional abundance of loggerhead and leatherback turtles could oscillate interannually according to oceanographic and climatic conditions. The Western Mediterranean is an important fishing area for the Spanish drifting longline fleet, which mainly targets swordfish, bluefin tuna, and albacore. Due to the spatial overlapping in fishing activity and turtle distribution, there is an increasing sea turtle conservation concern. The main goal of this study is to analyse the interannual bycatch of loggerhead and leatherback turtles by the Spanish Mediterranean longline fishery and to test the relationship between the total turtle by-catch of this fishery and the North Atlantic Oscillation (NAO). During the 14 years covered in this study, the number of sea turtle bycatches was 3,940 loggerhead turtles and 8 leatherback turtles, 0.499 loggerhead turtles/1000 hooks and 0.001014 leatherback turtles/1000 hooks. In the case of the loggerhead turtle the positive phase of the NAO favours an increase of loggerhead turtles in the Western Mediterranean Sea. However, in the case of leatherback turtle the negative phase of the NAO favours the presence of leatherback turtle. This contraposition could be related to the different ecophysiological response of both species during their migration cycle. PMID:24764769

  19. Interannual Differences for Sea Turtles Bycatch in Spanish Longliners from Western Mediterranean Sea

    PubMed Central

    Báez, José C.; García-Barcelona, Salvador

    2014-01-01

    Recent studies showed that regional abundance of loggerhead and leatherback turtles could oscillate interannually according to oceanographic and climatic conditions. The Western Mediterranean is an important fishing area for the Spanish drifting longline fleet, which mainly targets swordfish, bluefin tuna, and albacore. Due to the spatial overlapping in fishing activity and turtle distribution, there is an increasing sea turtle conservation concern. The main goal of this study is to analyse the interannual bycatch of loggerhead and leatherback turtles by the Spanish Mediterranean longline fishery and to test the relationship between the total turtle by-catch of this fishery and the North Atlantic Oscillation (NAO). During the 14 years covered in this study, the number of sea turtle bycatches was 3,940 loggerhead turtles and 8 leatherback turtles, 0.499 loggerhead turtles/1000 hooks and 0.001014 leatherback turtles/1000 hooks. In the case of the loggerhead turtle the positive phase of the NAO favours an increase of loggerhead turtles in the Western Mediterranean Sea. However, in the case of leatherback turtle the negative phase of the NAO favours the presence of leatherback turtle. This contraposition could be related to the different ecophysiological response of both species during their migration cycle. PMID:24764769

  20. Characterization of West Nile virus isolates from Spain: new insights into the distinct West Nile virus eco-epidemiology in the Western Mediterranean.

    PubMed

    Sotelo, Elena; Fernandez-Pinero, Jovita; Llorente, Francisco; Agüero, Montserrat; Hoefle, Ursula; Blanco, Juan M; Jiménez-Clavero, Miguel A

    2009-12-20

    West Nile virus (WNV) is a mosquito-borne flavivirus which causes important morbidity and mortality in birds, horses and humans. In the Western Mediterranean region, WNV causes sporadic, self-limited outbreaks, with few or no human cases. Here we report the characterization of two recent Western Mediterranean WNV isolates, obtained in Spain in 2007 from two golden eagles. Complete genome sequence comparisons revealed high identity between these isolates and close relationship with other Western Mediterranean WNV strains isolated since 1996. Phylogenetic analysis within this group indicated that two distinct phylogenetic groups have emerged from earlier strains. Pathogenicity analysis in mice showed that the Spanish isolate is less pathogenic than other strains either from the Western Mediterranean (Morocco 2003) or from North America (NY'99). Changes in amino acid position NS3-249 (claimed as a virulence marker) did not influence the pathogenicity observed. PMID:19833373

  1. The Isotopic History of Western North American Grasslands

    NASA Astrophysics Data System (ADS)

    Crowley, B. E.; Koch, P. L.

    2007-12-01

    Over the last 20 years, researchers have detected a rise in carbon isotope values of fossil mammals, paleosol minerals, and organic substrates roughly 6 to 8 Ma, which indicates an increase in the relative abundance of C4 grass at localities around the world. Prior research has shown that this increase in C4 abundance did not occur in cool high latitude regions, nor did it occur at sites around the Mediterranean. Similarly, modern California and Nevada do not support native C4 grasses. These states have a water regime similar to the Mediterranean region, with hot and dry summers, and most precipitation occurring during the cool winter months. Because the amount of C4 grass in North American ecosystems correlates positively with growing season temperature, it is not surprising that these western states, which have a winter growing season, do not support C4 plants. This does not necessarily imply, however, that C4 plants have never been favored in these western states. We used the carbon isotope composition of fossil ungulate tooth enamel as a proxy for C4 plant abundance in California and Nevada from 18 Ma to the present. Our carbon isotope data suggest that whereas there are very few native C4 species living in California or Nevada today, C4 plants may have been present in the region as early as the Late Miocene. Furthermore, there is an indication that C4 plants may have increased in abundance in the region during Pleistocene glacial periods.

  2. Modern view of Western Mediterranean hydrography (Arne Richter Award Lecture for OYS)

    NASA Astrophysics Data System (ADS)

    Schroeder, Katrin

    2015-04-01

    water has spread out into the western Mediterranean so that now it forms a bottom layer of warm salty water up to 1000 m thick throughout the western Mediterranean basin. The new bottom water has provided a natural tracer release experiment for understanding how bottom water fills the basin. The processes of deep water formation, the filling of the western Mediterranean with the new deep waters formed in the north, and the mixing between old and new deep waters are keys to understand how the Mediterranean is changing under changing climate conditions. An important open issue is how the old and new deep waters mix, on what time scale and by what processes, and in particular to quantify the role of turbulent mixing in the overall diffuse upwelling, the returning branch of the vertical thermohaline circulation.

  3. Heat flow map of the western Mediterranean basins

    SciTech Connect

    Foucher, J.P.; Burrus, J.; Vedova, B.D.

    1988-08-01

    More than 400 terrestrial heat flow determinations have been carried our in the western Mediterranean basins. These include results of detailed surveys in the Ligurian Sea and in the Gulf of Lions and Tyrrhenian basins, as well as sparse measurements in the Gulf of Valencia and the Algerian basin. Most of the measurements are surficial, obtained from the temperatures sensed by outrigged thermistors mounted on weight-driven probes penetrating the sediment to 3 to 10 m. Thermal conductivity was measured either on cores or in situ. The authors present a heat flow map of the western Mediterranean basins based on the available geothermal results. Mean regional heat flow values range from 55 to 105 mW m/sup /minus/2/ in the Lugiran and Gulf of Lions basin and from 50 to 200 m mW m/sup /minus/2/ in the Tyrrhenian Sea. In the latter basin, high heat flow characterizes areas of recent intensive thinning of the continental crust and associated incipient oceanic crust formation. In the former basins, heat flow tends to increase from the Provencal coast of France to the Corsican and Sardinian margins, which may reflect on increasing heat contribution from the mantle.

  4. Present-day stress field in the Gibraltar Arc (western Mediterranean)

    NASA Astrophysics Data System (ADS)

    FernáNdez-IbáñEz, F.; Soto, J. I.; Zoback, M. D.; Morales, J.

    2007-08-01

    The Gibraltar Arc in the western Mediterranean consists of the Betic and Rif Alpine chains and the Alboran Sea Basin. Four types of stress indicators (wellbore breakouts, earthquake focal plane mechanisms, young geologic fault slip data, and hydraulic fracture orientations) indicate a regional NW-SE compressive stress field resulting from Africa-Eurasia plate convergence. In some particular regions, deviations of SHmax are observed with respect to the regional stress field. They are gentle-to-moderate (22°-36°) anticlockwise rotations located along the North Alboran margin and moderate-to-significant (36°-78°) clockwise rotations around the Trans-Alboran Shear Zone (TASZ). This is a broad fault zone composed of different left-lateral strike-slip fault segments running from the eastern Betics to the Alhoceima region in the Rif and resulting in a major bathymetric high in the Alboran Sea (the Alboran Ridge fault zone). Some of these stress rotations appear to be controlled by steep gradients of crustal thickness variation across the North Alboran margin and/or differential loading imposed by thick sedimentary accumulations in basin depocenters parallel to the shoreline. Other stress perturbations may be related to active left-lateral, strike-slip deformation within the TASZ that crosscuts the entire orogenic arc on a NE-SW trend and represents a key element to understand present-day deformation partitioning in the western Mediterranean.

  5. Diversity, distribution and population size structure of deep Mediterranean gorgonian assemblages (Menorca Channel, Western Mediterranean Sea)

    NASA Astrophysics Data System (ADS)

    Grinyó, Jordi; Gori, Andrea; Ambroso, Stefano; Purroy, Ariadna; Calatayud, Clara; Dominguez-Carrió, Carlos; Coppari, Martina; Lo Iacono, Claudio; López-González, Pablo J.; Gili, Josep-Maria

    2016-06-01

    Gorgonians are a key group of organisms in benthic marine communities with a wide bathymetric and geographical distribution. Although their presence on continental shelves and slopes has been known for more than 100 years, knowledge concerning the ecology of deep gorgonian species is still in a very preliminary stage. To overcome this situation, gorgonian assemblages located at 40-360 m depth were studied over a large geographical area on the continental shelf and upper slope of the Menorca Channel (Western Mediterranean Sea). A quantitative analysis of video transects recorded by a manned submersible and a remotely operated vehicle, were used to examine the diversity, distribution and demography of gorgonian species. Results showed high gorgonian diversity within this depth range (a total of nine species were observed) compared to Mediterranean coastal areas. Gorgonian assemblages on the continental shelf and upper slope were mostly monospecific (respectively 73% and 76% of occupied sampling units contained one single species), whereas shelf edge assemblages were highly multispecific (92% of occupied sampling units contained several species). This contrasts with the monospecificity of Mediterranean coastal gorgonian assemblages. Gorgonian populations on the continental shelf were mostly dominated by small colonies (88% of measured colonies) with few intermediate and large colonies (12% of measured colonies). In deeper areas small colonies were still dominant (60% of measured colonies), but intermediate and large colonies were much more abundant (40% of measured colonies). This suggests high recruitment rates on the continental shelf, but perturbations (trammel nets, long lines and strong storms) may limit the presence of intermediate and large colonies. Conversely, on the shelf edge and upper slope a more stable environment may allow colonies to reach larger dimensions. The identification and ecological characterization of these deep assemblages further extends

  6. The thrust belts of Western North America

    SciTech Connect

    Moulton, F.C.

    1993-08-01

    Most of the Basin and Range physiographic province of western North America is now believed to be part of the overthrust. The more obvious overthrust belt along the eastern edge of the Basin and Range Province is named the Sevier orogenic belt, where older rocks are observed thrust onto younger rocks. More detailed surface geological mapping, plus deep multiple-fold geophysical work and many oil and gas wildcat wells, have confirmed an east-vergent shortened and stacked sequence is present in many places in the Basin and Range. This western compressive deformed area in east central Nevada is now named the Elko orogenic belt by the U.S. Geological Survey. This older compressed Elko orogenic belt started forming approximately 250 m.y. ago when the North American plate started to move west as the Pangaea supercontinent started to fragment. The North American plate moved west under the sediments of the Miogeocline that were also moving west. Surface-formed highlands and oceanic island arcs on the west edge of the North American plate restricted the westward movement of the sediments in the Miogeocline, causing east-vergent ramp thrusts to form above the westward-moving North American plate. The flat, eastward-up-cutting thrust assemblages moved on the detachment surfaces.

  7. Major storm periods and climate forcing in the Western Mediterranean during the Late Holocene

    NASA Astrophysics Data System (ADS)

    Degeai, Jean-Philippe; Devillers, Benoît; Dezileau, Laurent; Oueslati, Hamza; Bony, Guénaëlle

    2015-12-01

    Big storm events represent a major risk for populations and infrastructures settled on coastal lowlands. In the Western Mediterranean, where human societies colonized and occupied the coastal areas since the Ancient times, the variability of storm activity for the past three millennia was investigated with a multi-proxy sedimentological and geochemical study from a lagoonal sequence. Mappings of the geochemistry and magnetic susceptibility of detrital sources in the watershed of the lagoon and from the coastal barriers were undertaken in order to track the terrestrial or coastal/marine origin of sediments deposited into the lagoon. The multi-proxy analysis shows that coarser material, low magnetic susceptibility, and high strontium content characterize the sedimentological signature of the paleostorm levels identified in the lagoonal sequence. A comparison with North Atlantic and Western Mediterranean paleoclimate proxies shows that the phases of high storm activity occurred during cold periods, suggesting a climatically-controlled mechanism for the occurrence of these storm periods. Besides, an in-phase storm activity pattern is found between the Western Mediterranean and Northern Europe. Spectral analyses performed on the Sr content revealed a new 270-year solar-driven pattern of storm cyclicity. For the last 3000 years, this 270-year cycle defines a succession of ten major storm periods (SP) with a mean duration of 96 ± 54 yr. Periods of higher storm activity are recorded from >680 to 560 cal yr BC (SP10, end of the Iron Age Cold Period), from 140 to 820 cal yr AD (SP7 to SP5) with a climax of storminess between 400 and 800 cal yr AD (Dark Ages Cold Period), and from 1230 to >1800 cal yr AD (SP3 to SP1, Little Ice Age). Periods of low storm activity occurred from 560 cal yr BC to 140 cal yr AD (SP9 and SP8, Roman Warm Period) and from 820 to 1230 cal yr AD (SP4, Medieval Warm Period).

  8. Aerosol optical, microphysical and radiative properties at regional background insular sites in the western Mediterranean

    NASA Astrophysics Data System (ADS)

    Sicard, Michaël; Barragan, Rubén; Dulac, François; Alados-Arboledas, Lucas; Mallet, Marc

    2016-09-01

    In the framework of the ChArMEx (the Chemistry-Aerosol Mediterranean Experiment; http://charmex.lsce.ipsl.fr/) program, the seasonal variability of the aerosol optical, microphysical and radiative properties derived from AERONET (Aerosol Robotic Network; http://aeronet.gsfc.nasa.gov/) is examined in two regional background insular sites in the western Mediterranean Basin: Ersa (Corsica Island, France) and Palma de Mallorca (Mallorca Island, Spain). A third site, Alborán (Alborán Island, Spain), with only a few months of data is considered for examining possible northeast-southwest (NE-SW) gradients of the aforementioned aerosol properties. The AERONET dataset is exclusively composed of level 2.0 inversion products available during the 5-year period 2011-2015. AERONET solar radiative fluxes are compared with ground- and satellite-based flux measurements. To the best of our knowledge this is the first time that AERONET fluxes are compared with measurements at the top of the atmosphere. Strong events (with an aerosol optical depth at 440 nm greater than 0.4) of long-range transport aerosols, one of the main drivers of the observed annual cycles and NE-SW gradients, are (1) mineral dust outbreaks predominant in spring and summer in the north and in summer in the south and (2) European pollution episodes predominant in autumn. A NE-SW gradient exists in the western Mediterranean Basin for the aerosol optical depth and especially its coarse-mode fraction, which all together produces a similar gradient for the aerosol direct radiative forcing. The aerosol fine mode is rather homogeneously distributed. Absorption properties are quite variable because of the many and different sources of anthropogenic particles in and around the western Mediterranean Basin: North African and European urban areas, the Iberian and Italian peninsulas, most forest fires and

  9. Tsunami deposits in the Balearic Islands (western Mediterranean) and implications for hazard assessment.

    NASA Astrophysics Data System (ADS)

    Paris, Raphael; Wassmer, Patrick; Roger, Jean; Loevenbruck, Anne

    2010-05-01

    Significant earthquakes occur along the north Algerian and Carboneras faults (e.g. Djijelli 1865, Zemmouri 2003) and they may generate tsunamis in the western Mediterranean Basin and Alboran Sea, where tsunami hazard are poorly documented. The coast of southern Spain and Balearic Islands are densely populated, with touristic areas and important harbors. The 2003 event generated a small tsunami in the Balearic Islands (ships were moved by oscillations during more than 2 hours in some harbors). Reicherter et al. (2009) found evidences of two past tsunamis in lagoon of the Cabo de Gata (near Almeria), which they ascribed to the 1522 earthquake and an earlier event (< 850 BP). Field surveys along the coasts of Mallorca and Menorca islands revealed few evidences of past tsunamis. Thin sandy layers with marine bioclasts, possibly deposited by tsunamis, were found in three areas at altitudes always lower than 2m. Boulder clusters were found along the southern coast of Mallorca, but they could have been deposited by storms as well. These investigations are realized in the framework of the MAREMOTI project, funded by the French ANR and leaded by the CEA - DASE. Reicherter, K., Becker-Heidmann, P., 2009. Tsunami deposits in the western Mediterranean: remains of the 1522 Almeria earthquake? Geological Society Special Publications, London, 316, 217-235.

  10. The distribution and cycling of mercury species in the western Mediterranean

    NASA Astrophysics Data System (ADS)

    Cossa, Daniel; Martin, Jean-Marie; Takayanagi, Kazufumi; Sanjuan, Jane

    Total mercury concentrations were determined in water samples from ten vertical profiles in the western Mediterranean. Most Hg concentrations ranged from 0.5 to 4 pM, with a geometric mean of 2.26 pM. Such concentrations are in the same range as those measured in the North Atlantic and equatorial Pacific waters. There is no indication that the presence of geothermal activity or cinnabar deposits around the Mediterranean basin induces higher mercury concentrations in waters. Vertical concentration profiles were characterized by a maximum just below the thermocline, which is mainly developed in regions with relatively high primary production in the overlying waters. These observations support the remobilization model according to which, the mercury, associated with degradable organic matter, is solubilized from the particles accumulated in the thermocline layer. Additional measurements of certain mercury species, including reactive mercury (HgR) and gaseous species [elemental mercury (Hg°) and dimethylmercury (DMHg)], were performed on three profiles in the Alboran Sea and the Strait of Gibraltar. While 50% of the total mercury consisted of unidentified organic association, a maximum of the three determined species were observed below the thermocline: up to 0.71 pM, 0.43 pM and 0.30 pM for HgR, Hg° and DMHg, respectively. DMHg and Hg° appear to be formed in the low oxygen zone. A specific methylation rate of 3 × 10-9 s-1 can be estimated, which is six times higher than the values proposed for the North Atlantic waters (Mason et al., 1995a, Water, Air and Soil Pollution, 80, 665-677). The mass balance budget in the western Mediterranean shows that, while the total mercury exchanges at the straits are not unbalanced, mercury enters the Mediterranean as inorganic mercury and is exported to the Atlantic Ocean partially as methylated species. Riverine input is mainly composed by particulate mercury which is readily accumulated in coastal sediments. The dissolved

  11. Environmental footprints of Mediterranean versus Western dietary patterns: beyond the health benefits of the Mediterranean diet

    PubMed Central

    2013-01-01

    Background Dietary patterns can substantially vary the resource consumption and environmental impact of a given population. Dietary changes such as the increased consumption of vegetables and reduced consumption of animal products reduce the environmental footprint and thus the use of natural resources. The adherence of a given population to the Mediterranean Dietary Pattern (MDP) through the consumption of the food proportions and composition defined in the new Mediterranean Diet pyramid can thus not only influence human health but also the environment. The aim of the study was to analyze the sustainability of the MDP in the context of the Spanish population in terms of greenhouse gas emissions, agricultural land use, energy consumption and water consumption. Furthermore, we aimed to compare the current Spanish diet with the Mediterranean Diet and in comparison with the western dietary pattern, exemplified by the U.S.A. food pattern, in terms of their corresponding environmental footprints. Methods The environmental footprints of the dietary patterns studied were calculated from the dietary make-up of each dietary pattern, and specific environmental footprints of each food group. The dietary compositions were obtained from different sources, including food balance sheets and household consumption surveys. The specific environmental footprints of food groups were obtained from different available life-cycle assessments. Results The adherence of the Spanish population to the MDP has a marked impact on all the environmental footprints studied. Increasing adherence to the MDP pattern in Spain will reduce greenhouse gas emissions (72%), land use (58%) and energy consumption (52%), and to a lower extent water consumption (33%). On the other hand, the adherence to a western dietary pattern implies an increase in all these descriptors of between 12% and 72%. Conclusions The MDP is presented as not only a cultural model but also as a healthy and environmentally

  12. Instantaneous mantle dynamics of the Western Mediterranean region

    NASA Astrophysics Data System (ADS)

    Mohammadi, S.; Geenen, T.; van den Berg, A. P.; Spakman, W.

    2012-04-01

    Our research is concerned with the establishment of links between deep mantle processes and surface deformation. Our main focus is on the instantaneous mantle dynamics of the European-Mediterranean region and its surface responses. Here we have constructed instantaneous 3-D dynamic models of the Western Mediterranean region with focus on subduction below Betic-Rif-Alboran region. The driving forces in the models are due to temperature variation, which is derived from seismic tomography. The tomography model, which is used in our research, is the global P-wave speed model UU-P07 (M. Amaru, PhD Thesis, Utrecht University, 2007; Van der Meer et al., Nature Geoscience, 2010). For the subducted slab in this region we have assumed a temperature profile according to the Jurassic-Early Cretaceous age of the oceanic lithosphere. The boundary conditions used in the dynamic models allow us to include constraints from motions of the larger tectonic plates regarding the convergence of African and Eurasian plates. We present the topography response and the predicted patterns of surface deformations for this region based on a number of assumptions regarding the scaling of tomography to temperature and density, and rheology. A depth and temperature dependent rheology is assumed for most of the domain. Lithosphere faults are modeled with low viscosity zones. The mesh-generating tool used enables us to have finer resolution at the scale of a few kilometers in fault zones and along plate boundaries in the area of interest. 1) This research is part of the EUROCORES TOPO-EUROPE, particularly of project TOPO-4D

  13. Connection between South Mediterranean climate and North African atmospheric circulation during the last 50,000 yr BP North Atlantic cold events

    NASA Astrophysics Data System (ADS)

    Bout-Roumazeilles, V.; Combourieu Nebout, N.; Peyron, O.; Cortijo, E.; Landais, A.; Masson-Delmotte, V.

    2007-12-01

    High-resolution clay mineralogical analyses were performed on sediment deposited during the last 50,000 yr in the Alboran sea (ODP Site 976). The clay mineral record is compared with pollen assemblages and with annual precipitation (Pann) and mean temperatures of the coldest month (MTCO) reconstructed with the modern analog technique (MAT). Enhanced contribution of palygorskite, a typical wind-blown clay mineral, characterizes the North Atlantic cold climatic events. Coeval development of the semi-arid vegetation (Artemisia rich) associated with a drastic fall of reconstructed precipitations and temperatures, suggest cold and arid continental conditions in the West Mediterranean area during North Atlantic cold events. The clay mineral association, especially the palygorskite content and the illite-to-kaolinite ratio, indicate western Morocco as one of the major source of the clay-size fraction during the North Atlantic cold events. The maximum abundance of Artemisia associated with the presence of Argania pollen both indicate Morocco as the main origin for pollen during these cold periods. The comparison of these pollen and clay mineral-specific features allows us to pinpoint western Morocco as the dominant source of wind-blown particles during North Atlantic cold events. These specific mineralogical composition and palynological assemblages reveal enhanced aridity over North Africa and intensification of winds favouring dust erosion and transport from North Africa toward the Alboran Sea during the North Atlantic cold events. According to atmospheric models, such a meridian transport (1) likely results from the development of strong and stable anticyclonic conditions over the tropical Atlantic and North Africa, similar to today's summer meteorological configuration and (2) implies a northward position of the westerly winds during North Atlantic cold events. Finally the synoptic situation over the West Mediterranean during the North Atlantic cold events is compared

  14. Historical biogeography of the land snail Cornu aspersum: a new scenario inferred from haplotype distribution in the Western Mediterranean basin

    PubMed Central

    2010-01-01

    Background Despite its key location between the rest of the continent and Europe, research on the phylogeography of north African species remains very limited compared to European and North American taxa. The Mediterranean land mollusc Cornu aspersum (= Helix aspersa) is part of the few species widely sampled in north Africa for biogeographical analysis. It then provides an excellent biological model to understand phylogeographical patterns across the Mediterranean basin, and to evaluate hypotheses of population differentiation. We investigated here the phylogeography of this land snail to reassess the evolutionary scenario we previously considered for explaining its scattered distribution in the western Mediterranean, and to help to resolve the question of the direction of its range expansion (from north Africa to Europe or vice versa). By analysing simultaneously individuals from 73 sites sampled in its putative native range, the present work provides the first broad-scale screening of mitochondrial variation (cyt b and 16S rRNA genes) of C. aspersum. Results Phylogeographical structure mirrored previous patterns inferred from anatomy and nuclear data, since all haplotypes could be ascribed to a B (West) or a C (East) lineage. Alternative migration models tested confirmed that C. aspersum most likely spread from north Africa to Europe. In addition to Kabylia in Algeria, which would have been successively a centre of dispersal and a zone of secondary contacts, we identified an area in Galicia where genetically distinct west and east type populations would have regained contact. Conclusions Vicariant and dispersal processes are reviewed and discussed in the light of signatures left in the geographical distribution of the genetic variation. In referring to Mediterranean taxa which show similar phylogeographical patterns, we proposed a parsimonious scenario to account for the "east-west" genetic splitting and the northward expansion of the western (B) clade which

  15. Cementation of Upper Miocene reefs in western Mediterranean

    SciTech Connect

    Esteban, M.; Calvet, F.

    1983-03-01

    Coral reefs in the western Mediterranean (southeast Spain, Balearic Island, northern Morocco, Sicily, and Italy) show a wide variety of cement types, ranging from completely tight, well-cemented, to poorly cemented reefs with most of the primary porosity still preserved. Cementation processes in those coral reefs appear to be controlled to a great extent by repeated changes of relative sea levels and regional variations of seawater chemistry. Reef progradation occurred during four to six (or more) important sea level changes, resulting in complicated geometric relationships of reef complexes and their freshwater lenses. Progradation occurred during sea level rises and falls and is reflected in abrupt escarpments in some field localities, generally separated by important terraced erosional surfaces. Various types of aragonitic isopachous cement fringes of marine origin, 0.1 to 1.5 cm (.04 to .6 in.) thick, are well preserved in some localities. This is probably due to subsequent plugging by gypsum cement during the Messinian salinity crises. Another possible effect of salinity fluctuations is the abundance of thick crusts of peletoidal, micrite cement of marine origin, locally forming about three-fourths of the volume of the reef core.

  16. The Overthrust Belt of Western North America

    SciTech Connect

    Verrall, P.

    1993-02-01

    The Overthrust Belt extends for 5000 mi (8000 km) from the Brooks Range in Alaska to the Sierra Madre Oriental in Mexico. It consists of northeastward vergent thrust and fold structures involving late Precambrian to early Tertiary sedimentary section. These sediments represent deposition off the western rift margin, formed in late Precambrian time, of the North American Precambrian craton. The northeastward thrusting continued throughout the Mesozoic as a response to the convergence of the East Pacific Plate with the North American Plate. This convergence resulted in subduction beneath the North American Plate except at the northwest end (the Brooks Range) where the result was obduction. Convergence ceased when the west edge of the East Pacific Plate reached the subduction zone. The sedimentary section involved in the Thrust Belt contains good Devonian to Cretaceous hydrocarbon source rocks, and Ordovician to traps related to the thrusting (simple thrust sheets, imbricate thrust sheets, folded thrust sheets, step anticlines, footwall cutoffs, footwall anticlines, etc.). Field methods involved in exploration for hydrocarbons include field geological mapping, remote sensing (aerial photography and Landsat imagery), various seismic refraction and seismic reflection techniques (including modern detailed three dimension surveys) and potential field methods such as gravity and magnetic surveying. Studies of the field data include paleontology, source rock and hydrocarbon migration studies, structural and stratigraphic analyses, and the processing of geophysical data. This work has succeeded in two major areas: the Western Canadian Rocky Mountain Foothills, a major gas province producing mainly from Paleozoic reservoirs; and the Wyoming-Idaho-Utah portion of the thrust belt, also a major gas producer from Paleozoic reservoirs and, in addition, a major oil producer from the Jurassic Nugget Sandstone.

  17. Aerosol properties over the western Mediterranean basin: temporal and spatial variability

    NASA Astrophysics Data System (ADS)

    Lyamani, H.; Valenzuela, A.; Perez-Ramirez, D.; Toledano, C.; Granados-Muñoz, M. J.; Olmo, F. J.; Alados-Arboledas, L.

    2015-03-01

    This study focuses on the analysis of Aerosol Robotic Network (AERONET) aerosol data obtained over Alborán Island (35.90° N, 3.03° W, 15 m a.s.l.) in the western Mediterranean from July 2011 to January 2012. Additional aerosol data from the three nearest AERONET stations (Málaga, Oujda and Palma de Mallorca) and the Maritime Aerosol Network (MAN) were also analyzed in order to investigate the temporal and spatial variations of aerosol over this scarcely explored region. High aerosol loads over Alborán were mainly associated with desert dust transport from North Africa and occasional advection of anthropogenic fine particles from central European urban-industrial areas. The fine particle load observed over Alborán was surprisingly similar to that obtained over the other three nearest AERONET stations, suggesting homogeneous spatial distribution of fine particle loads over the four studied sites in spite of the large differences in local sources. The results from MAN acquired over the Mediterranean Sea, Black Sea and Atlantic Ocean from July to November 2011 revealed a pronounced predominance of fine particles during the cruise period.

  18. 18. Detail of stonework, north side, immediately west of western ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    18. Detail of stonework, north side, immediately west of western abutment reinforcing, facing south. - Dubbs Bridge, Spinnerstown Road (State Route 2031) spanning Hosensack Creek, Dillingerville, Lehigh County, PA

  19. 1. VIEW SOUTH, NORTH ELEVATION Delaware, Lackawanna & Western ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    1. VIEW SOUTH, NORTH ELEVATION - Delaware, Lackawanna & Western Railroad Freight & Rail Yard, Multiple Unit Light Inspection Shed, New Jersey Transit Hoboken Terminal Rail Yard, Hoboken, Hudson County, NJ

  20. 2. VIEW NORTH, SOUTH ELEVATION Delaware, Lackawanna & Western ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    2. VIEW NORTH, SOUTH ELEVATION - Delaware, Lackawanna & Western Railroad Freight & Rail Yard, Multiple Unit Light Inspection Shed, New Jersey Transit Hoboken Terminal Rail Yard, Hoboken, Hudson County, NJ

  1. New and rare sponges from the deep shelf of the Alboran Island (Alboran Sea, Western Mediterranean).

    PubMed

    Sitjà, Cèlia; Maldonado, Manuel

    2014-01-01

    The sponge fauna from the deep shelf (70 to 200 m) of the Alboran Island (Alboran Sea, Western Mediterranean) was investigated using a combination of ROV surveys and collecting devices in the frame of the EC LIFE+ INDEMARES Grant aimed to designate marine areas of the Nature 2000 Network within Spanish territorial waters. From ROV surveys and 351 examined specimens, a total of 87 sponge species were identified, most belonging in the Class Demospongiae, and one belonging in the Class Hexactinellida. Twenty six (29%) species can be regarded as either taxonomically or faunistically relevant. Three of them were new to science (Axinella alborana nov. sp.; Axinella spatula nov. sp.; Endectyon filiformis nov. sp.) and 4 others were Atlantic species recorded for the first time in the Mediterranean Sea (Jaspis eudermis Lévi & Vacelet, 1958; Hemiasterella elongata Topsent, 1928; Axinella vellerea Topsent, 1904; Gelliodes fayalensis Topsent, 1892). Another outstanding finding was a complete specimen of Rhabdobaris implicata Pulitzer-Finali, 1983, a species only known from its holotype, which had entirely been dissolved for its description. Our second record of the species has allowed a neotype designation and a restitution of the recently abolished genus Rhabdobaris Pulitzer-Finally, 1983, also forcing a slight modification of the diagnosis of the family Bubaridae. Additionally, 12 species were recorded for the first time from the shelf of the Alboran Island, including a few individuals of the large hexactinellid Asconema setubalense Kent, 1877 that provided the second Mediterranean record of this "North Atlantic" hexactinellid. ROV explorations also revealed that sponges are an important component of the deep-shelf benthos, particularly on rocky bottoms, where they make peculiar sponge gardens characterized by a wide diversity of small, erect species forming a dense "undergrowth" among a scatter of large sponges and gorgonians. The great abundance and the taxonomic

  2. Aerosol properties over the western Mediterranean Basin: temporal and spatial variability

    NASA Astrophysics Data System (ADS)

    Lyamani, H.; Valenzuela, A.; Perez-Ramirez, D.; Toledano, C.; Granados-Muñoz, M. J.; Olmo, F. J.; Alados-Arboledas, L.

    2014-08-01

    This study focuses on the analysis of AERONET aerosol data obtained over Alborán Island (35.95° N, 3.01° W, 15 m a.s.l.) in the western Mediterranean from July 2011 to January 2012. Additional aerosol data from three nearest AERONET stations and the Maritime Aerosol Network (MAN) were also analyzed in order to investigate the aerosol temporal and spatial variations over this scarcely explored region. Aerosol load over Alborán was significantly larger than that reported for open oceanic areas not affected by long-range transport. High aerosol loads over Alborán were mainly associated with desert dust transport from North Africa and occasional advection of anthropogenic fine particles from Italy. The fine particle load observed over Alborán was surprisingly similar to that obtained over the other three nearest AERONET stations in spite of the large differences in local aerosol sources. The results from MAN acquired over the Mediterranean Sea, Black Sea and Atlantic Ocean from July to November 2011 revealed a pronounced predominance of fine particles during the cruise period. Alborán was significantly less influenced by anthropogenic particles than the Black Sea and central and eastern Mediterranean regions during the cruise period. Finally, the longer AERONET dataset from Málaga (36.71° N, 4.4° W, 40 m a.s.l.), port city in southern Spain, shows that no significant changes in columnar aerosol loads since the European Directive on ship emissions was implemented in 2010 were observed over this site.

  3. Variability of mineral dust deposition in the western Mediterranean basin and south-east of France

    NASA Astrophysics Data System (ADS)

    Vincent, Julie; Laurent, Benoit; Losno, Rémi; Bon Nguyen, Elisabeth; Roullet, Pierre; Sauvage, Stéphane; Chevaillier, Servanne; Coddeville, Patrice; Ouboulmane, Noura; di Sarra, Alcide Giorgio; Tovar-Sánchez, Antonio; Sferlazzo, Damiano; Massanet, Ana; Triquet, Sylvain; Morales Baquero, Rafael; Fornier, Michel; Coursier, Cyril; Desboeufs, Karine; Dulac, François; Bergametti, Gilles

    2016-07-01

    Previous studies have provided some insight into the Saharan dust deposition at a few specific locations from observations over long time periods or intensive field campaigns. However, no assessment of the dust deposition temporal variability in connection with its regional spatial distribution has been achieved so far from network observations over more than 1 year. To investigate dust deposition dynamics at the regional scale, five automatic deposition collectors named CARAGA (Collecteur Automatique de Retombées Atmosphériques insolubles à Grande Autonomie in French) have been deployed in the western Mediterranean region during 1 to 3 years depending on the station. The sites include, from south to north, Lampedusa, Majorca, Corsica, Frioul and Le Casset (southern French Alps). Deposition measurements are performed on a common weekly period at the five sites. The mean dust deposition fluxes are higher close to the northern African coasts and decrease following a south-north gradient, with values from 7.4 g m-2 year-1 in Lampedusa (35°31' N, 12°37' E) to 1 g m-2 year-1 in Le Casset (44°59' N, 6°28' E). The maximum deposition flux recorded is of 3.2 g m-2 wk-1 in Majorca with only two other events showing more than 1 g m-2 wk-1 in Lampedusa, and a maximum of 0.5 g m-2 wk-1 in Corsica. The maximum value of 2.1 g m-2 year-1 observed in Corsica in 2013 is much lower than existing records in the area over the 3 previous decades (11-14 g m-2 year-1). From the 537 available samples, 98 major Saharan dust deposition events have been identified in the records between 2011 and 2013. Complementary observations provided by both satellite and air mass trajectories are used to identify the dust provenance areas and the transport pathways from the Sahara to the stations for the studied period. Despite the large size of African dust plumes detected by satellites, more than 80 % of the major dust deposition events are recorded at only one station, suggesting that the dust

  4. Paleoceanography. Onset of Mediterranean outflow into the North Atlantic.

    PubMed

    Hernández-Molina, F Javier; Stow, Dorrik A V; Alvarez-Zarikian, Carlos A; Acton, Gary; Bahr, André; Balestra, Barbara; Ducassou, Emmanuelle; Flood, Roger; Flores, José-Abel; Furota, Satoshi; Grunert, Patrick; Hodell, David; Jimenez-Espejo, Francisco; Kim, Jin Kyoung; Krissek, Lawrence; Kuroda, Junichiro; Li, Baohua; Llave, Estefania; Lofi, Johanna; Lourens, Lucas; Miller, Madeline; Nanayama, Futoshi; Nishida, Naohisa; Richter, Carl; Roque, Cristina; Pereira, Hélder; Sanchez Goñi, Maria Fernanda; Sierro, Francisco J; Singh, Arun Deo; Sloss, Craig; Takashimizu, Yasuhiro; Tzanova, Alexandrina; Voelker, Antje; Williams, Trevor; Xuan, Chuang

    2014-06-13

    Sediments cored along the southwestern Iberian margin during Integrated Ocean Drilling Program Expedition 339 provide constraints on Mediterranean Outflow Water (MOW) circulation patterns from the Pliocene epoch to the present day. After the Strait of Gibraltar opened (5.33 million years ago), a limited volume of MOW entered the Atlantic. Depositional hiatuses indicate erosion by bottom currents related to higher volumes of MOW circulating into the North Atlantic, beginning in the late Pliocene. The hiatuses coincide with regional tectonic events and changes in global thermohaline circulation (THC). This suggests that MOW influenced Atlantic Meridional Overturning Circulation (AMOC), THC, and climatic shifts by contributing a component of warm, saline water to northern latitudes while in turn being influenced by plate tectonics.

  5. Paleoceanography. Onset of Mediterranean outflow into the North Atlantic.

    PubMed

    Hernández-Molina, F Javier; Stow, Dorrik A V; Alvarez-Zarikian, Carlos A; Acton, Gary; Bahr, André; Balestra, Barbara; Ducassou, Emmanuelle; Flood, Roger; Flores, José-Abel; Furota, Satoshi; Grunert, Patrick; Hodell, David; Jimenez-Espejo, Francisco; Kim, Jin Kyoung; Krissek, Lawrence; Kuroda, Junichiro; Li, Baohua; Llave, Estefania; Lofi, Johanna; Lourens, Lucas; Miller, Madeline; Nanayama, Futoshi; Nishida, Naohisa; Richter, Carl; Roque, Cristina; Pereira, Hélder; Sanchez Goñi, Maria Fernanda; Sierro, Francisco J; Singh, Arun Deo; Sloss, Craig; Takashimizu, Yasuhiro; Tzanova, Alexandrina; Voelker, Antje; Williams, Trevor; Xuan, Chuang

    2014-06-13

    Sediments cored along the southwestern Iberian margin during Integrated Ocean Drilling Program Expedition 339 provide constraints on Mediterranean Outflow Water (MOW) circulation patterns from the Pliocene epoch to the present day. After the Strait of Gibraltar opened (5.33 million years ago), a limited volume of MOW entered the Atlantic. Depositional hiatuses indicate erosion by bottom currents related to higher volumes of MOW circulating into the North Atlantic, beginning in the late Pliocene. The hiatuses coincide with regional tectonic events and changes in global thermohaline circulation (THC). This suggests that MOW influenced Atlantic Meridional Overturning Circulation (AMOC), THC, and climatic shifts by contributing a component of warm, saline water to northern latitudes while in turn being influenced by plate tectonics. PMID:24926012

  6. Biochronology, paleobiogeography and faunal turnover in western Mediterranean Cenozoic mammals.

    PubMed

    Palombo, Maria R

    2009-12-01

    Cenozoic terrestrial mammals from Sardinia contribute substantial information for reconstructing the complex history of the western Mediterranean. The occurrence of endemic perissodactyls in Eocene marine and marsh deposits suggests the existence of ecological or physical barriers between the Corso-Sardinian massif and the Iberian-Occitanic area. At the end of the Oligocene, isolation of Sardinia was almost complete, although a migration from Europe occurred at the beginning of the Early Miocene, as indicated by the unbalanced endemic fauna from Oschiri. During the Late Miocene, the Tusco-Sardinian palaeobioprovince came into existence as an isolated region inhabited by the quite diversified, but notably endemic, Oreopithecus fauna. Sardinia was definitely isolated from Tuscany by the Messinian, but temporary connections with the European mainland possibly allowed the colonization of forerunners of some Sardinian Pliocene taxa. During the Plio-Pleistocene, Sardinia maintained permanent isolation. However, sea level drop, resulting in a relatively short distance between Sardinia and the European mainland, allowed different migratory events. From the Late Pliocene to the Late Pleistocene-Holocene, two main mammalian faunal complexes (FC) can be recognized: the Nesogoral FC (Late Pliocene-Early Pleistocene) and the Microtus (Tyrrhenicola) FC (late Early Pleistocene-Early Holocene). At the transition from Nesogoral to Microtus (Tyrrhenicola) FC, approximately 47% of the genera and 76% of the species disappeared, while approximately 58% of the genera and 71% of the species appeared. A noticeable turnover followed the arrival of Neolithic man and his accompanying fauna. Nonetheless, Praemegaceros was still present at about 7000 years BP, while Microtus (Tyrrhenicola) and Prolagus are respectively recorded in the Bronze and Iron Ages.

  7. Tectonic and petrologic evolution of the Western Mediterranean: the double polarity subduction model

    NASA Astrophysics Data System (ADS)

    Melchiorre, Massimiliano; Vergés, Jaume; Fernàndez, Manel; Torné, Montserrat; Casciello, Emilio

    2016-04-01

    The geochemical composition of the mantle beneath the Mediterranean area is extremely heterogeneous. This feature results in volcanic products whose geochemical features in some cases do not correspond to the geodynamic environment in which they are sampled and that is observed at present day. The subduction-related models that have been developed during the last decades to explain the evolution of the Western Mediterranean are mainly based on geologic and seismologic evidences, as well as petrography and age of exhumation of the metamorphic units that compose the inner parts of the different arcs. Except few cases, most of these models are poorly constrained from a petrologic point of view. Usually the volcanic activity that affected the Mediterranean area since Oligocene has been only used as a corollary, and not as a key constrain. This choice is strictly related to the great geochemical variability of the volcanic products erupted in the Western Mediterranean, due to events of long-term recycling affecting the mantle beneath the Mediterranean since the Variscan Orogeny, together with depletion episodes due to partial melting. We consider an evolutionary scenario for the Western Mediterranean based on a double polarity subduction model according to which two opposite slabs separated by a transform fault of the original Jurassic rift operated beneath the Western and Central Mediterranean. Our aim has been to reconstruct the evolution of the Western Mediterranean since the Oligocene considering the volcanic activity that affected this area since ~30 Ma and supporting the double polarity subduction model with the petrology of the erupted rocks.

  8. Influence of environmental parameters on the life-history and population dynamics of cuttlefish Sepia officinalis in the western Mediterranean

    NASA Astrophysics Data System (ADS)

    Keller, Stefanie; Valls, Maria; Hidalgo, Manuel; Quetglas, Antoni

    2014-05-01

    The cuttlefish Sepia officinalis constitutes an important fishery resource in the Mediterranean, where it is exploited by both the bottom trawl and small-scale fleet. However, there is currently scarce information on the Mediterranean stocks, since most studies on the population dynamics of this species have been undertaken in the northeast Atlantic. In this work we first analysed different aspects of the cuttlefish life-history from the western Mediterranean such as population structure, reproduction and the trade-offs between somatic condition and reproduction investments. Secondly, we investigated the effects of different environmental parameters (e.g. climate indices, sea surface temperature (SST), rainfall, chlorophyll-a concentration (Chla) and moon phase) on these populations, analysing several landing time series spanning the last 45 years. Our results revealed that Mediterranean cuttlefish populations exhibit strong seasonal variations owing to a reproductive migration towards coastal waters. The positive relationships between somatic and reproductive condition pointed to an income breeder strategy; this was reinforced by the percentage of empty stomachs, which was lowest just before the reproductive period peak. Despite the putative high sensitivity of cephalopod populations to external abiotic factors, our results showed that Mediterranean cuttlefish populations were not affected by most of the environmental parameters investigated. Significant effects were found for SST and a local climatic index, but no or very weak influences were evident for other parameters such as large-scale climatic phenomena (e.g. North Atlantic Oscillation, Mediterranean Oscillation) or other locally-related variables (e.g. rainfall, Chla). Our results revealed a shift in the cuttlefish population dynamics in the early 1980s, which could be related to important changes in the local hydroclimatology reported by previous authors.

  9. North-south palaeohydrological contrasts in the central Mediterranean during the Holocene: tentative synthesis and working hypotheses

    NASA Astrophysics Data System (ADS)

    Magny, M.; Combourieu-Nebout, N.; de Beaulieu, J. L.; Bout-Roumazeilles, V.; Colombaroli, D.; Desprat, S.; Francke, A.; Joannin, S.; Ortu, E.; Peyron, O.; Revel, M.; Sadori, L.; Siani, G.; Sicre, M. A.; Samartin, S.; Simonneau, A.; Tinner, W.; Vannière, B.; Wagner, B.; Zanchetta, G.; Anselmetti, F.; Brugiapaglia, E.; Chapron, E.; Debret, M.; Desmet, M.; Didier, J.; Essallami, L.; Galop, D.; Gilli, A.; Haas, J. N.; Kallel, N.; Millet, L.; Stock, A.; Turon, J. L.; Wirth, S.

    2013-09-01

    On the basis of a multi-proxy approach and a strategy combining lacustrine and marine records along a north-south transect, data collected in the central Mediterranean within the framework of a collaborative project have led to reconstruction of high-resolution and well-dated palaeohydrological records and to assessment of their spatial and temporal coherency. Contrasting patterns of palaeohydrological changes have been evidenced in the central Mediterranean: south (north) of around 40° N of latitude, the middle part of the Holocene was characterised by lake-level maxima (minima), during an interval dated to ca. 10 300-4500 cal BP to the south and 9000-4500 cal BP to the north. Available data suggest that these contrasting palaeohydrological patterns operated throughout the Holocene, both on millennial and centennial scales. Regarding precipitation seasonality, maximum humidity in the central Mediterranean during the middle part of the Holocene was characterised by humid winters and dry summers north of ca. 40° N, and humid winters and summers south of ca. 40° N. This may explain an apparent conflict between palaeoclimatic records depending on the proxies used for reconstruction as well as the synchronous expansion of tree species taxa with contrasting climatic requirements. In addition, south of ca. 40° N, the first millennium of the Holocene was characterised by very dry climatic conditions not only in the eastern, but also in the central- and the western Mediterranean zones as reflected by low lake levels and delayed reforestation. These results suggest that, in addition to the influence of the Nile discharge reinforced by the African monsoon, the deposition of Sapropel 1 has been favoured (1) by an increase in winter precipitation in the northern Mediterranean borderlands, and (2) by an increase in winter and summer precipitation in the southern Mediterranean area. The climate reversal following the Holocene climate optimum appears to have been punctuated

  10. Fueling plankton production by a meandering frontal jet: a case study for the Alboran Sea (Western Mediterranean).

    PubMed

    Oguz, Temel; Macias, Diego; Garcia-Lafuente, Jesus; Pascual, Ananda; Tintore, Joaquin

    2014-01-01

    A three dimensional biophysical model was employed to illustrate the biological impacts of a meandering frontal jet, in terms of efficiency and persistency of the autotrophic frontal production, in marginal and semi-enclosed seas. We used the Alboran Sea of the Western Mediterranean as a case study. Here, a frontal jet with a width of 15-20 km, characterized by the relatively low density Atlantic water mass, flows eastward within the upper 100 m as a marked meandering current around the western and the eastern anticyclonic gyres prior to its attachment to the North African shelf/slope topography of the Algerian basin. Its inherent nonlinearity leads to the development of a strong ageostrophic cross-frontal circulation that supplies nutrients into the nutrient-starved euphotic layer and stimulates phytoplankton growth along the jet. Biological production is larger in the western part of the basin and decreases eastwards with the gradual weakening of the jet. The higher production at the subsurface levels suggests that the Alboran Sea is likely more productive than predicted by the satellite chlorophyll data. The Mediterranean water mass away from the jet and the interiors of the western and eastern anticyclonic gyres remain unproductive. PMID:25372789

  11. Flash heat simulation events in the north Mediterranean basin

    NASA Astrophysics Data System (ADS)

    Mazon, Jordi; Pino, David

    2013-04-01

    According to the definition of flash heat event proposed by Mazon et al. in the European Meteorology Meeting (2011 and 2012) from the studied case produced in the Northeast of the Iberian peninsula on 27th August 20120, some other flash heat events have been detected by automatic weather stations around the in the Mediterranean basin (South Italy, Crete island, South Greece and the northeast of the Iberian peninsula). Flash heat event covers those events in which a large increase of temperature last a spatial and temporal scale between heat wave (defined by the WMO as a phenomenon in which the daily maximum temperature of more than five consecutive days exceeds the average maximum temperature by 5°C, with respect to the 1961-1990 period) and heat burst (defined by the AMS as a rare atmospheric event characterized by gusty winds and a rapid increase in temperature and decrease in humidity that can last some minutes). Thus flash heat event may be considered as a rapid modification of the temperature that last several hours, lower than 48 hours, but usually less than 24 hours. Two different flash heat events have been simulated with the WRF mesoscale model in the Mediterranean basin. The results show that two different mechanisms are the main causes of these flash heat events. The first one occurred on 23rd March 2008 in Crete Island due to a strong Foehn effect caused by a strong south and southeast wind, in which the maximum temperature increased during some hours on the night at 32°C. The second one occurred on 1st August 2012 in the northeast of the Iberian Peninsula, caused by a rapid displacement of warm a ridge from North Africa that lasted around 24 hours.

  12. WMOP: The SOCIB Western Mediterranean Sea OPerational forecasting system

    NASA Astrophysics Data System (ADS)

    Renault, Lionel; Juza, Mélanie; Garau, Bartolomé; Sayol, Juan Manuel; Orfila, Alejandro; Tintoré, Joaquín

    2013-04-01

    Development of science based ocean-forecasting systems at global, regional, sub-regional and local scales is needed to increase our understanding of ocean processes and to support knowledge based management of the marine environment. In this context, WMOP (Western Mediterranean sea /Balearic OPerational system) is the forecasting subsystem component of SOCIB, the new Balearic Islands Coastal Observing and Forecasting System. The WMOP system is operational since the end of 2010. The ROMS model is forced every 3 hours with atmospheric forcing derived from AEMET/Hirlam and daily boundary conditions provided by MFS2 from MyOcean/MOON. Model domain is implemented over an area extending from Gibraltar strait to Corsica/Sardinia (from 6°W to 9°E and from 35°N to 44.5°N), including Balearic Sea and Gulf of Lion. The grid is 631 x 539 points with a resolution of ~1.5km, which allows good representation of mesoscale and submesoscale features (first baroclinic Rossby radius ~10-15 km) of key relevance in this region. The model has 30 sigma levels, and the vertical s coordinate is stretched for boundary layer resolution, also essential to capture extreme events water masses formation and dynamical effects. Bottom topography is derived from a 2' resolution database. Online validation procedures based on inter-comparison of model outputs against observing systems and reference models such as MFS and Mercator are used to assess at what level the numerical models are able to reproduce the features observed from in-situ systems and remote sensing. The intrinsic three-dimensional variability of the coastal ocean and open-ocean exchanges imply the need of muti-plaform observing systems covering a variety of scales. Fixed moorings provide a good temporal resolution but poor spatial coverage, while satellite products provide a good spatial coverage but just on the surface layer. Gliders can provide a reasonable spatial variability in both horizontal and vertical axes. Thus, inter

  13. A newly discovered Pliocene volcanic field on the western Sardinia continental margin (western Mediterranean)

    NASA Astrophysics Data System (ADS)

    Conforti, Alessandro; Budillon, Francesca; Tonielli, Renato; De Falco, Giovanni

    2016-02-01

    A previously unknown submerged volcanic field offshore western Sardinia (western Mediterranean Sea), has been identified based on swath bathymetric data collected in 2009, 2010 and 2013, and high-resolution seismic profiles collected in 2011 and 2013. About 40 conical-shaped volcanic edifices (maximum width of about 1600 m and maximum height of about 180 m) and several lava outcrops (up to 1,200 m wide) were recognized at 20 to 150 m water depth over an area of 800 km2. The volcanic edifices are mainly eruptive monogenic vents, mostly isolated with a rather distinct shape, or grouped to form a coalescent volcanic body in which single elements are often still recognizable. High-resolution seismics enabled identifying relationships between the volcanic bodies and continental margin successions. The edifices overlie a major erosional surface related to the margin exposure following the Messinian salinity crisis, and are overlain by or interbedded with an early Pliocene marine unit. This seismo-stratigraphic pattern dates the volcanic activity to the early Pliocene, in agreement with the radiometric age of the Catalano island lavas (4.7 Ma) reported in earlier studies. The morphometry of the volcanic bodies suggests that cone erosion was higher at shallow water depths. Indeed, most of the shallow edifices are strongly eroded and flattened at 125 to 130 m water depth, plausibly explained by recurrent sub-aerial exposure during Pleistocene sea-level lowstands, whereas cones in deeper water are much better preserved. Volcanic vents and lava deposits, hereafter named the Catalano volcanic field (CVF), are emplaced along lineaments corresponding to the main directions of the normal fault system, which lowered the Sinis Basin and the western Sardinia continental margin. The CVF represents a volumetrically relevant phase of the late Miocene - Quaternary anorogenic volcanic cycle of Sardinia, which is related to the first stage of the extensional tectonics affecting the island

  14. Lagged influence of North Atlantic Oscillation on population dynamics of a Mediterranean terrestrial salamander

    NASA Astrophysics Data System (ADS)

    Salvidio, Sebastiano; Oneto, Fabrizio; Ottonello, Dario; Pastorino, Mauro V.

    2016-04-01

    The North Atlantic Oscillation (NAO) is a large-scale climatic pattern that strongly influences the atmospheric circulation in the northern Hemisphere and by consequence the long-term variability of marine and terrestrial ecosystem over great part of northern Europe and western Mediterranean. In the Mediterranean, the effects of the NAO on vertebrates has been studied mainly on bird populations but was rarely analysed in ectothermic animals, and in particular in amphibians. In this study, we investigated the relationships between winter, spring and summer NAO indexes and the long-term population dynamics of the plethodontid salamander Speleomantes strinatii. This terrestrial salamander was monitored inside an artificial cave in NW Italy for 24 consecutive years. The relationships between seasonal NAO indexes and the salamander dynamics were assessed by cross-correlation function (CCF) analysis, after prewhitening the time series by autoregressive moving average statistical modelling. Results of CCF analyses indicated that the salamander abundance varied in relation to the one-year ahead winter NAO ( P = 0.018), while no relationships were found with spring and summer indexes. These results strengthen some previous findings that suggested a high sensitivity of temperate terrestrial amphibians to wintertime climatic conditions.

  15. Plate boundary evolution in the western-central Mediterranean: From the past to the present.

    NASA Astrophysics Data System (ADS)

    Wortel, Rinus; Faccenna, Claudio; Govers, Rob; Polonia, Alina; Baes, Marzieh

    2013-04-01

    The evolution of the Calabrian and Gibraltar arcs and that of the margins of northern Africa and Sicily are part of the final phase of opening of the western Mediterranean basins. Jointly, they are the central topic of the TopoMed project concerning the plate boundary reorganization of the western-central Mediterranean, one of the projects of the TOPO-EUROPE programme (EUROCORES/ESF). The structure and evolution of the Gibraltar arc region are discussed in a separate presentation. This final stage of opening shows intriguing lateral variations from the Calabrian Arc, via the northern margin of Sicily to the North-African (Algerian) margin. In concert, they provide an excellent opportunity to study the evolution of an expanding oceanic realm that may be at the verge of entering a new phase of closure. Our studies encompass detailed analyses of deep penetration seismic data, multibeam bathymetry and field observations, and numerical model experiments addressing lithospheric scale process-oriented aspects. Special attention is given to the aspect that the region is embedded in a context of ongoing Africa-Eurasia plate convergence and to the role of structures, inherited from earlier stages of basin opening, in controlling the recent and ongoing evolution. For the Calabrian accretionary wedge the focus is on assessing the present state of deformation, including seismic activity, and other accompanying processes. We show that the Calabrian wedge is segmented (in direction along the arc) in two different lobes, the western and eastern lobe corresponding with detached and still continuous parts of the subducting slab, respectively. For the Northern Sicily margin we propose that its earlier history involving STEP faulting has preconditioned the lithosphere structure to the extent that it promotes initiation of a new southward-dipping subduction zone. The northern African margin is in a very special transitional situation in which the retreating northward subduction has

  16. Novel fen ecosystems in western North Carolina

    NASA Astrophysics Data System (ADS)

    Wilcox, J. D.

    2012-12-01

    Western North Carolina is mountainous, and groundwater flows from hillslope recharge zones to valley stream and spring discharge zones. Depending on surface topography and geologic conditions, the water table may approach or intersect the ground surface to form seepage wetlands, or fens. Fen ecosystems can be very sensitive to changes in land use, groundwater pumping, and upslope development. This presentation will focus on two sites where historical land use and human activity played important roles in creating or preserving fen ecosystems. Both sites now support—and are being managed to protect—federally endangered flora and fauna. The first site is home to Sarracenia oreophilia, an endangered pitcher plant that thrives on saturated soils with low nutrient content. The site's early history includes tree clearing, drain tile installation, and cattle grazing, while more recent management activities have included drain tile excavation, manual invasive removal, and prescribed burns. A 15-year water-level record indicates seasonal artesian conditions wet a 3m clay unit (K=2E-5 cm/sec) beneath the site, which is able to retain moisture during drier periods. Shorter "clay wetting periods" during drought years (1999-2000; 2007-2008) correspond to reduced clump counts in pitcher-plant surveys. The second site is a former aggregate quarry that now supports over 60 bog turtles (Clemmys muhlenbergii). The biggest threat to this site is encroachment of non-native and invasive multiflora rose (Rosa multiflora) and other large woody species. Management activities include manual removal and prescribed goat herbivory. Current efforts to characterize the springs, water-table, and surface-water flows will be used to detect changes in the future to the hydrologic regime in the fen.

  17. Browning boreal forests of western North America

    NASA Astrophysics Data System (ADS)

    Verbyla, David

    2011-12-01

    , suggesting that direct temperature stress might be a factor in some species. Since warm growing seasons are also typically dry growing seasons, direct temperature stress and moisture stress could occur simultaneously. For example, 2004 was the warmest summer in over 200 years in boreal Alaska (Barber et al 2004) but it was also during a drought with less than 50 mm of summer precipitation recorded in Fairbanks. In Fairbanks, the length of the growing season, as defined as the period above freezing, has increased by 45 per cent over the past 100 years, with no significant increase in precipitation (Wendler and Shulski 2009). Regional winter runoff has increased, likely associated with permafrost thawing (Brabets and Walvoord 2009), while surface water has decreased, likely associated with increased evapotranspiration (Riordan et al 2006, Anderson et al 2007, Berg et al 2009). The mean annual air temperature in boreal Alaska has increased by over 1.5 °C during the past 50 years (Stafford et al 2000), and is projected to increase by 3-7 °C by end of this century (Walsh et al 2008). Thus, it would be surprising if a declining NDVI trend was not occurring in the western boreal region of North America as the climate continues to warm. Insects and disease in the North American boreal forest may also affect the NDVI browning trends (Malmström and Raffa 2000), as the life histories of damaging insects may be linked to a warming boreal climate. For example, warmer temperatures contributed to the spruce beetle outbreaks in Alaska with a reduction in the beetle life cycle from two years to one year (Berg et al 2006). Thus, as the boreal climate continues to warm, tree growth reduction and mortality from insects and diseases may become more substantial. In boreal Alaska, recent alder dieback and mortality is likely to be related to alder's susceptibility to a canker-causing fungus in drought years (Ruess et al 2009). Recent widespread and prolonged outbreaks of aspen leaf miner and a

  18. What drives LGM precipitation over the western Mediterranean? A study focused on the Iberian Peninsula and northern Morocco

    NASA Astrophysics Data System (ADS)

    Beghin, P.; Charbit, S.; Kageyama, M.; Combourieu-Nebout, N.; Hatté, C.; Dumas, C.; Peterschmitt, J.-Y.

    2016-04-01

    The evolution of precipitation is a key question concerning future climatic changes, especially in regions like the Mediterranean area which are currently prone to droughts. The influence of atmospheric circulation changes (in the mid-latitude westerlies or in the strength of the subtropical subsidence), along with changes in local mechanisms generating precipitation (such as convection) make it difficult to predict precipitation changes confidently over this area. Understanding its governing mechanisms is crucial. A possible approach is to test our understanding on different documented past climatic contexts. This paper focuses on the Last Glacial Maximum period (LGM) over the western Mediterranean region and puts in perspective the available information inferred from paleo-climatic records and the outputs of nine global climate models. We first review the available information on LGM precipitation in this region and find that the environmental conditions prevailing at this period range from humid to semi-arid, depending on the proxies. Model outputs from the PMIP3-CMIP5 database also yield a wide range of mean annual responses in this area, from wetter to drier conditions with respect to the pre-industrial period. This variety of responses allows to investigate the mechanisms governing LGM precipitation in the western Mediterranean area. Over the Iberian Peninsula and northern Morocco, most models simulate a larger amount of LGM precipitation in winter w.r.t. the pre-industrial period. This feature is mainly due to the large-scale effect of the southward shift of the North Atlantic jet stream, which is closely associated with the surface air temperature changes over the northwestern North Atlantic. In summer, precipitation changes mainly result from convection and are correlated to local surface air temperature anomalies, highlighting the key role of local processes. These contrasted changes in winter and summer, linked to different mechanisms, could explain the

  19. EVIDENCE OF AIRBORNE CONTAMINATION OF WESTERN NORTH AMERICAN MOUNTAIN ECOSYSTEMS

    EPA Science Inventory

    There is emerging evidence that mountain ecosystems in the western USA are receiving deposition of persistent bioaccumulative toxicants with origins in North America and elsewhere in the Northern Hemisphere. The toxic materials include metals and organic compounds. Of particula...

  20. Floating plastic debris in the Central and Western Mediterranean Sea.

    PubMed

    Ruiz-Orejón, Luis F; Sardá, Rafael; Ramis-Pujol, Juan

    2016-09-01

    In two sea voyages throughout the Mediterranean (2011 and 2013) that repeated the historical travels of Archduke Ludwig Salvator of Austria (1847-1915), 71 samples of floating plastic debris were obtained with a Manta trawl. Floating plastic was observed in all the sampled sites, with an average weight concentration of 579.3 g dw km(-2) (maximum value of 9298.2 g dw km(-2)) and an average particle concentration of 147,500 items km(-2) (the maximum concentration was 1,164,403 items km(-2)). The plastic size distribution showed microplastics (<5 mm) in all the samples. The most abundant particles had a surface area of approximately 1 mm(2) (the mesh size was 333 μm). The general estimate obtained was a total value of 1455 tons dw of floating plastic in the entire Mediterranean region, with various potential spatial accumulation areas. PMID:27540696

  1. Seafloor imagery from the BIG'95 debris flow, western Mediterranean

    NASA Astrophysics Data System (ADS)

    Lastras, G.; Canals, M.; Hughes-Clarke, J. E.; Moreno, A.; de Batist, M.; Masson, D. G.; Cochonat, P.

    2002-10-01

    Seafloor backscatter data are used to image the product of one of the youngest major mass-wasting events in the northwestern Mediterranean Sea: a 26 km3 debris-flow deposit that covers 2000 km2 of the Ebro continental slope and base of slope, offshore Spain. Backscatter images provide unprecedented insights on debris-flow dynamics in the deep sea. A pattern of low-backscatter patches represents large sediment blocks that moved while keeping their internal coherence. High-backscatter alignments restricted to topographic lows that represent coarse sediment pathways separate the blocks. The results presented prove the occurrence of large catastrophic sediment failures near heavily populated coastal areas even in continental margins considered to be geodynamically quiet, such as those of the northwestern Mediterranean.

  2. Interannual variability of the Mediterranean outflow observed in Espartel sill, western Strait of Gibraltar

    NASA Astrophysics Data System (ADS)

    GarcíA-Lafuente, J.; Delgado, J.; SáNchez RomáN, A.; Soto, J.; Carracedo, L.; DíAz Del RíO, G.

    2009-10-01

    Four-year time series of observations in Espartel sill at the western part of the Strait of Gibraltar have been analyzed in order to investigate the variability of the Mediterranean outflow. It is assumed that the observed variability comes from the changing properties of the dense waters that are located at the maximum depth from where they can be uplifted in the upstream basin (Alborán Sea, inside the Mediterranean Sea) and evacuated through the strait. From this perspective, the following three mechanisms are investigated: (1) the replenishment of the deep basin by newly formed Western Mediterranean Deep Water that, depending on its density, can either uplift old resident waters or lay above them leaving in any case a cold signature in the temperature series; (2) the presence/absence of the energetic anticyclonic gyres in the Alborán Sea, particularly the western one, which can transfer momentum to the underlying Mediterranean vein and provide it with additional energy to ascend over the sills of the strait; and (3) the meteorologically enhanced flows that follow the rapid changes of atmospheric pressure over the western Mediterranean basin, which would be able to aspire deeper waters residing in the upstream basin. The three mechanisms act on different timescales, from annual in case (1) to monthly in case (2) to weekly in case (3) although these two latter are modulated annually by the seasonal prevalence of the western Alborán gyre in summer and of the strong meteorologically driven fluctuations in winter. The mechanisms overlap at annual timescales making it difficult to separate out the different contributions.

  3. Population genetic history of Aristeus antennatus (Crustacea: Decapoda) in the Western and Central Mediterranean Sea.

    PubMed

    Marra, Annamaria; Mona, Stefano; Sà, Rui M; D'Onghia, Gianfranco; Maiorano, Porzia

    2015-01-01

    Aristeus antennatus is an ecologically and economically important deep-water species in the Mediterranean Sea. In this study we investigated the genetic variability of A. antennatus sampled from 10 sampling stations in the Western and Central Mediterranean. By comparing our new samples with available data from the Western area, we aim to identify potential genetic stocks of A. antennatus and to reconstruct its historical demography in the Mediterranean. We analyzed two regions of mitochondrial DNA in 319 individuals, namely COI and 16S. We found two main results: i) the genetic diversity values consistent with previous data within the Mediterranean and the absence of barriers to gene flow within the Mediterranean Sea; ii) a constant long-term effective population size in almost all demes but a strong signature of population expansion in the pooled sample about 50,000 years B.P./ago. We propose two explanation for our results. The first is based on the ecology of A. antennatus. We suggest the existence of a complex meta-population structured into two layers: a deeper-dwelling stock, not affected by fishing, which preserves the pattern of historical demography; and genetically homogeneous demes inhabiting the fishing grounds. The larval dispersal, adult migration and continuous movements of individuals from "virgin" deeper grounds not affected by fishing to upper fishing areas support an effective 'rescue effect' contributing to the recovery of the exploited stocks and explain their genetic homogeneity throughout the Mediterranean Sea. The second is based on the reproduction model of this shrimp: the high variance in offspring production calls for a careful interpretation of the data observed under classical population genetics and Kingman's coalescent. In both cases, management policies for A. antennatus will therefore require careful evaluation of the meta-population dynamics of all stocks in the Mediterranean. In the future, it will be particularly relevant to

  4. Population genetic history of Aristeus antennatus (Crustacea: Decapoda) in the Western and Central Mediterranean Sea.

    PubMed

    Marra, Annamaria; Mona, Stefano; Sà, Rui M; D'Onghia, Gianfranco; Maiorano, Porzia

    2015-01-01

    Aristeus antennatus is an ecologically and economically important deep-water species in the Mediterranean Sea. In this study we investigated the genetic variability of A. antennatus sampled from 10 sampling stations in the Western and Central Mediterranean. By comparing our new samples with available data from the Western area, we aim to identify potential genetic stocks of A. antennatus and to reconstruct its historical demography in the Mediterranean. We analyzed two regions of mitochondrial DNA in 319 individuals, namely COI and 16S. We found two main results: i) the genetic diversity values consistent with previous data within the Mediterranean and the absence of barriers to gene flow within the Mediterranean Sea; ii) a constant long-term effective population size in almost all demes but a strong signature of population expansion in the pooled sample about 50,000 years B.P./ago. We propose two explanation for our results. The first is based on the ecology of A. antennatus. We suggest the existence of a complex meta-population structured into two layers: a deeper-dwelling stock, not affected by fishing, which preserves the pattern of historical demography; and genetically homogeneous demes inhabiting the fishing grounds. The larval dispersal, adult migration and continuous movements of individuals from "virgin" deeper grounds not affected by fishing to upper fishing areas support an effective 'rescue effect' contributing to the recovery of the exploited stocks and explain their genetic homogeneity throughout the Mediterranean Sea. The second is based on the reproduction model of this shrimp: the high variance in offspring production calls for a careful interpretation of the data observed under classical population genetics and Kingman's coalescent. In both cases, management policies for A. antennatus will therefore require careful evaluation of the meta-population dynamics of all stocks in the Mediterranean. In the future, it will be particularly relevant to

  5. Population Genetic History of Aristeus antennatus (Crustacea: Decapoda) in the Western and Central Mediterranean Sea

    PubMed Central

    Marra, Annamaria; Mona, Stefano; Sà, Rui M.; D’Onghia, Gianfranco; Maiorano, Porzia

    2015-01-01

    Aristeus antennatus is an ecologically and economically important deep-water species in the Mediterranean Sea. In this study we investigated the genetic variability of A. antennatus sampled from 10 sampling stations in the Western and Central Mediterranean. By comparing our new samples with available data from the Western area, we aim to identify potential genetic stocks of A. antennatus and to reconstruct its historical demography in the Mediterranean. We analyzed two regions of mitochondrial DNA in 319 individuals, namely COI and 16S. We found two main results: i) the genetic diversity values consistent with previous data within the Mediterranean and the absence of barriers to gene flow within the Mediterranean Sea; ii) a constant long-term effective population size in almost all demes but a strong signature of population expansion in the pooled sample about 50,000 years B.P./ago. We propose two explanation for our results. The first is based on the ecology of A. antennatus. We suggest the existence of a complex meta-population structured into two layers: a deeper-dwelling stock, not affected by fishing, which preserves the pattern of historical demography; and genetically homogeneous demes inhabiting the fishing grounds. The larval dispersal, adult migration and continuous movements of individuals from “virgin” deeper grounds not affected by fishing to upper fishing areas support an effective ‘rescue effect’ contributing to the recovery of the exploited stocks and explain their genetic homogeneity throughout the Mediterranean Sea. The second is based on the reproduction model of this shrimp: the high variance in offspring production calls for a careful interpretation of the data observed under classical population genetics and Kingman’s coalescent. In both cases, management policies for A. antennatus will therefore require careful evaluation of the meta-population dynamics of all stocks in the Mediterranean. In the future, it will be particularly

  6. Crustal deformation evidences for viscous coupling and fragmented lithosphere at the Nubia-Iberia plate boundary (Western Mediterranean)

    NASA Astrophysics Data System (ADS)

    Palano, Mimmo; González, Pablo J.; Fernández, José

    2016-04-01

    A spatially dense crustal velocity field, based on up to 15 years of GNSS observations at more than 380 sites and extensively covering the Iberian Peninsula and Northern Africa, allow us to provide new insights into two main tectonic processes currently occurring in this area. We detected a slow large-scale clockwise rotation of the Iberian Peninsula with respect to a local pole located closely to the northwestern sector of the Pyrenean mountain range (Palano et al., 2015). Although this crustal deformation pattern could suggest a rigid rotating lithosphere block, this model would predict significant shortening along the Western (off-shore Lisbon) and North Iberian margin which cannot totally ruled out but currently is not clearly observed. Conversely, we favour the interpretation that this pattern reflects the quasi-continuous straining of the ductile lithosphere in some sectors of South and Western Iberia in response to viscous coupling of the NW Nubia and Iberian plate boundary in the Gulf of Cádiz. Furthermore, the western Mediterranean basin appears fragmented into independent crustal tectonic blocks, which delimited by inherited lithospheric shear structures and trapped within the Nubia-Eurasia collision, are currently accommodating most of the plate convergence rate. Among these blocks, an (oceanic-like western) Algerian one is currently transferring a significant fraction of the Nubia-Eurasia convergence rate into the Eastern Betics (SE Iberia) and likely causing the eastward motion of the Baleares Promontory. Most of the observed crustal ground deformation can be attributed to processes driven by spatially variable lithospheric plate forces imposed along the Nubia-Eurasia convergence boundary. Nevertheless, the observed deformation field infers a very low convergence rates as observed also at the eastern side of the western Mediterranean, along the Calabro Peloritan Arc, by space geodesy (e.g. Palano, 2015). References Palano M. (2015). On the present

  7. Crustal and Lithospheric Structure of the Western Mediterranean: Pds Receiver Function Results from the PICASSO Experiment

    NASA Astrophysics Data System (ADS)

    Thurner, S.; Palomeras, I.; Levander, A.

    2012-12-01

    The Betic Mountains in southern Spain, the Gibraltar Arc, the Alboran Sea, and the Rif and Atlas Mountains in northern Africa comprise the western Mediterranean tectonic region, which has been affected by simultaneous extension and compression throughout the Cenozoic. Multiple geodynamic models have been invoked to explain the coeval compressional and extensional tectonic processes, including slab roll-back (Royden, 1993; Lonergan and White, 1997; Gutscher et al., 2002), accompanied and followed by lithospheric convective downwelling (Seber et al., 1996; Calvert et al., 2000), and delamination (Platt et al., 1996). We use Ps teleseismic receiver functions to investigate the crustal and lithospheric structure throughout this region. PICASSO (Program to Investigate Convective Alboran Sea System Overturn) is a multi-disciplinary, international investigation seeking to improve our understanding of the geodynamics of the western Mediterranean. The PICASSO deployment includes 89 broadband stations distributed linearly from central Spain to the Morocco-Algeria border. For this study we supplemented the PICASSO dataset with data from six other Moroccan, Spanish, Portuguese, and German networks in the region. Using 167 events (M > 6.0) recorded at a total of 240 stations we calculated 1 Hz and 2Hz receiver functions. The receiver functions were then CCP stacked to create a 3D image volume of the region. The Pds receiver functions indicate crustal thicknesses between ~42-47 km in southern Spain beneath the Betic Mountains and ~35-45 km across the Gibraltar Strait. Beneath both the Rif and Betic Mountains we observe complex crustal structures, including two strong positive arrivals around Moho depth (~50 km). A number of models can explain this feature, including those associated thrust systems in each region. In Morocco, along a NW-SE transect from the Gibraltar Strait across the Atlas Mountains, we observe thick crust in the north beneath the Rif Mountains and to the south

  8. Pathogenicity of two recent Western Mediterranean West Nile virus isolates in a wild bird species indigenous to Southern Europe: the red-legged partridge.

    PubMed

    Sotelo, Elena; Gutierrez-Guzmán, Ana Valeria; del Amo, Javier; Llorente, Francisco; El-Harrak, Mehdi; Pérez-Ramírez, Elisa; Blanco, Juan Manuel; Höfle, Ursula; Jiménez-Clavero, Miguel Angel

    2011-01-01

    West Nile virus (WNV) is an emerging zoonotic pathogen whose geographic spread and incidence in humans, horses and birds has increased significantly in recent years. WNV has long been considered a mild pathogen causing self-limiting outbreaks. This notion has changed as WNV is causing large epidemics with a high impact on human and animal health. This has been particularly noteworthy since its introduction into North America in 1999. There, native bird species have been shown to be highly susceptible to WNV infection and disease with high mortalities. For this reason, the effect of WNV infection in North American bird species has been thoroughly studied by means of experimental inoculations in controlled trials. To a lesser extent, European wild birds have been shown to be affected clinically by WNV infection. Yet experimental studies on European wild bird species are lacking. The red-legged partridge (Alectoris rufa) is a gallinaceous bird indigenous to the Iberian Peninsula, widely distributed in South Western Europe. It plays a key role in the Mediterranean ecosystem and constitutes an economically important game species. As such it is raised intensively in outdoor facilities. In this work, red-legged partridges were experimentally infected with two recent WNV isolates from the Western Mediterranean area: Morocco/2003 and Spain/2007. All inoculated birds became viremic and showed clinical disease, with mortality rates of 70% and 30%, respectively. These results show that Western Mediterranean WNV variants can be pathogenic for some European bird species, such as the red-legged partridge. PMID:21314967

  9. Pathogenicity of two recent Western Mediterranean West Nile virus isolates in a wild bird species indigenous to Southern Europe: the red-legged partridge

    PubMed Central

    2011-01-01

    West Nile virus (WNV) is an emerging zoonotic pathogen whose geographic spread and incidence in humans, horses and birds has increased significantly in recent years. WNV has long been considered a mild pathogen causing self-limiting outbreaks. This notion has changed as WNV is causing large epidemics with a high impact on human and animal health. This has been particularly noteworthy since its introduction into North America in 1999. There, native bird species have been shown to be highly susceptible to WNV infection and disease with high mortalities. For this reason, the effect of WNV infection in North American bird species has been thoroughly studied by means of experimental inoculations in controlled trials. To a lesser extent, European wild birds have been shown to be affected clinically by WNV infection. Yet experimental studies on European wild bird species are lacking. The red-legged partridge (Alectoris rufa) is a gallinaceous bird indigenous to the Iberian Peninsula, widely distributed in South Western Europe. It plays a key role in the Mediterranean ecosystem and constitutes an economically important game species. As such it is raised intensively in outdoor facilities. In this work, red-legged partridges were experimentally infected with two recent WNV isolates from the Western Mediterranean area: Morocco/2003 and Spain/2007. All inoculated birds became viremic and showed clinical disease, with mortality rates of 70% and 30%, respectively. These results show that Western Mediterranean WNV variants can be pathogenic for some European bird species, such as the red-legged partridge. PMID:21314967

  10. Influence of the Mediterranean outflow on the isotopic composition of neodymium in waters of the North Atlantic

    NASA Technical Reports Server (NTRS)

    Piepgras, D. J.; Wasserburg, G. J.

    1983-01-01

    Measurements of the Nd-143/Nd-144 ratio, expressed as epsilon-Nd(0), made in sea water samples obtained at depths from 0 to 4850 m at stations 95, 101, and 30 of North-Atlantic cruise 109-1 of the RV Atlantis II are reported and analyzed. In the 1000-m sample at station 95, determined by salinity, O2, PO4, NO3, SiO2, potential-temperature, and pressure profiles to correspond to the core of the Mediterranean outflow, an epsilon-Nd(0) value of -9.8 + or - 0.6 was found, a significant increase over the layers above and below, where epsilon-Nd(0) is about -12. Mixing estimations give a value for pure Mediterranean waters of approximately -6; continental drainage or volcanic deep-sea sediments are considered possible sources for this more radiogenic Nd. The epsilon-Nd(0) peak in the western North Atlantic (station 30) is found at the surface, and the deep waters are less radiogenic than in the eastern North Atlantic, suggesting multiple Nd sources. Possible origins and distribution mechanisms are discussed.

  11. Recent benthic foraminiferal assemblages and their relationship to environmental variables on the shoreface and inner shelf off Valencia (western Mediterranean).

    PubMed

    López-Belzunce, María; Blázquez, Ana M; Pretus, Joan Lluís

    2014-10-01

    The environmental variables that determine the distributions of benthic foraminiferal assemblages on the shoreface and inner shelf of the north of Valencia province (Western Mediterranean) are identified. The possible influence of variables such as water depth, distance from shore, hydrodynamics, substrate type, carbonate content, organic matter content and human activity is evaluated. Multivariate cluster-Q-type analysis and redundancy analysis (RDA) are used to identify the environmental variables that have the greatest influence on the assemblage distribution. The spatial distribution of the assemblages is closely associated with water depth and substrate. The diversity and abundance of foraminifera shells increase with depth and their conservation improves. The most common species in the study area are Ammonia beccarii, Rosalina globularis, Buccella granulata, Planorbulina mediterranensis, and Lobatula lobatula. The presence of wastewater in the study area has not polluted the foraminiferal assemblages (absence of anomalous shells). The direction of the discharge plume is a potential source of nutrients for deep water.

  12. Amount and distribution of neustonic micro-plastic off the western Sardinian coast (Central-Western Mediterranean Sea).

    PubMed

    de Lucia, Giuseppe Andrea; Caliani, Ilaria; Marra, Stefano; Camedda, Andrea; Coppa, Stefania; Alcaro, Luigi; Campani, Tommaso; Giannetti, Matteo; Coppola, Daniele; Cicero, Anna Maria; Panti, Cristina; Baini, Matteo; Guerranti, Cristiana; Marsili, Letizia; Massaro, Giorgio; Fossi, Maria Cristina; Matiddi, Marco

    2014-09-01

    A plethora of different sampling methodologies has been used to document the presence of micro-plastic fragments in sea water. European Marine Strategy suggests to improve standard techniques to make future data comparable. We use Manta Trawl sampling technique to quantify abundance and distribution of micro-plastic fragments in Sardinian Sea (Western Mediterranean), and their relation with phthalates and organoclorine in the neustonic habitat. Our results highlight a quite high average plastic abundance value (0.15 items/m(3)), comparable to the levels detected in other areas of the Mediterranean. "Site" is the only factor that significantly explains the differences observed in micro-plastic densities. Contaminant levels show high spatial and temporal variation. In every station, HCB is the contaminant with the lowest concentration while PCBs shows the highest levels. This work, in line with Marine Strategy directives, represents a preliminary study for the analysis of plastic impact on marine environment of Sardinia. PMID:24776304

  13. Cenozoic geodynamic evolution of the western Mediterranean domain: A view from the Neogene peri-Tyrrhenian basins

    SciTech Connect

    Roure, F.; Montadert, L.; Mueller, C.

    1988-08-01

    Biostratigraphic and structural studies of synorogenic Neogene deposits in the southern Apennines, Calabria, and Cicily are compared to similar data from Sardinia and the Tyrrhenian Sea to trace the geodynamic evolution of the western Mediterranean domain.

  14. Parapsyche species (Trichoptera: Hydropsychidae: Arctopsychinae) of western North America.

    PubMed

    Givens, Donald R

    2015-12-14

    The adult female, pupa, and larva of the 5 western North American species of the arctopsychine genus Parapsyche-P. almota Ross 1938, P. elsis Milne 1936, P. extensa Denning 1949a, P. spinata Denning 1949b, and P. turbinata Schmid 1968-are reviewed. The female and larva of P. extensa are described for the first time. The larvae of P. spinata and P. turbinata are described for the first time. The chaetotaxy of the larval forms of western North American Parapsyche is discussed and scanning electron micrographs are presented. Keys to the females, known pupae, and larvae are provided. Distributional and biological data are also included.

  15. Parapsyche species (Trichoptera: Hydropsychidae: Arctopsychinae) of western North America.

    PubMed

    Givens, Donald R

    2015-01-01

    The adult female, pupa, and larva of the 5 western North American species of the arctopsychine genus Parapsyche-P. almota Ross 1938, P. elsis Milne 1936, P. extensa Denning 1949a, P. spinata Denning 1949b, and P. turbinata Schmid 1968-are reviewed. The female and larva of P. extensa are described for the first time. The larvae of P. spinata and P. turbinata are described for the first time. The chaetotaxy of the larval forms of western North American Parapsyche is discussed and scanning electron micrographs are presented. Keys to the females, known pupae, and larvae are provided. Distributional and biological data are also included. PMID:26701494

  16. Investigating frontal variability from repeated glider transects in the Ligurian Current (North West Mediterranean Sea)

    NASA Astrophysics Data System (ADS)

    Piterbarg, L.; Taillandier, V.; Griffa, A.

    2014-01-01

    Mesoscale variability of the Ligurian Current (North Western Mediterranean Sea) is studied using glider data from a repeated cross-frontal transect. The Ligurian Current is characterized by a complex time variability, with propagation velocities that can be compared to those of the glider. As a consequence, time variability can appear as folded into space variability in the glider data through the mechanism of Doppler smearing. In this paper, we provide a general framework to illustrate the effects of spatial and temporal variability and introduce a simple methodology to at least partially unfold the uncertainty. We capitalize on the fact that the glider repeatedly covers the transect, and we build time series of isopycnal depth at fixed points using nonlinear interpolation in time and spatial smoothing. Estimates of the isopycnal space patterns are obtained at various times, and a function fitting is used when appropriate allowing to describe the frontal time variability through a few descriptive parameters. Results show a mesoscale signal with scales consistent with what is known in the literature, and characterized by a cross-shore oscillation of the front between approximately 15 and 50 km offshore. The frontal oscillation is quite smooth during the first four transects with propagation speed significantly lower than the glider (≈ 8 km/day), so that the deconvolution method is robust. Local wind also appears to play a role. During the last two transects, instead, the system undergoes dramatic changes with time scales of the order of a day, so that the deconvolution is more problematic.

  17. Speleothem records of western Mediterranean. Hydrological variability along the Last Interglacial Period and marine linkages

    NASA Astrophysics Data System (ADS)

    Torner, Judit; Cacho, Isabel; Moreno, Ana; Stoll, Heather; Belmonte, Anchel; Sierro, Francisco J.; Frigola, Jaime; Martrat, Belen; Fornós, Joan; Arnau Fernández, Pedro; Hellstrom, John; Cheng, Hai; Edwards, R. Lawrence

    2016-04-01

    This study aims to identify and characterize regional hydrological variability in the western Mediterranean region in base to different geochemical parameters (δ18O, δ13C, and Mg/Ca ratios). Speleothems have been recovered from several caves located in southern central Pyrenees one and the others form the Balearic Islands. Their chronologies have been constructed in base on U/Th absolute dating and indicate that the speleothem sequences cover the end of the last interglacial and the glacial inception. One of the most remarkable features of the records is the intense and abrupt shift toward more arid conditions that marks the end of the last interglacial (MIS 5e). Furthermore, our speleothem records also show relatively humid but highly variable hydrological conditions during the interstadial periods from MIS 5c to 5a. These speleothem records have been compared with new generated western Mediterranean marine records from the Balearic Sea (MD99-2343) and Alboran Sea (OPD-977). Marine records include (1) proxies of sea surface temperature and changes in evaporation-precipitation rates based on pair analysis of δ18O and the Mg/Ca ratios in planktonic foraminifera Globigerina bulloides; (2) proxies of deep-water currents associated with the Western Mediterranean Deep Water (WMDW) based on grain size analyses. The results reveal that arid conditions on land were coeval with cold sea surface sub-stages (MIS 5b and 5d), and also with increases in the intensity of the WMDW-related currents. By contrast, humid and hydrological unstable atmosphere conditions were synchronous with sea surface warm sub-stages, and lower WMDW-related currents intensities (MIS 5a, c and e). Consequently, our results highly evidence a strong atmospheric-oceanic coupling, involving parallel changes in both surface but also deep western Mediterranean Sea conditions during the last interglacial period and the glacial inception.

  18. Carbonate speleothems from western Mediterranean gypsum karst: palaeoclimate implications

    NASA Astrophysics Data System (ADS)

    Columbu, Andrea; Drysdale, Russell; Woodhead, Jon; Chiarini, Veronica; De Waele, Jo; Hellstrom, John; Forti, Paolo; Sanna, Laura

    2016-04-01

    Gypsum caves are uncommon environments for carbonate speleothems (cave deposits). Contrary to limestone caves, the only source of non-atmospheric carbon is from biogenic CO2 produced by the overlying soils. Enhanced CO2 content in soils is in turn related with climate, where warm temperatures and high humidity favour plant activity .().....(Fairchild and Baker, 2012). Although poorly decorated, the exploration of northern Italian and Spanish gypsum karst systems reveals the existence of several generations of carbonate speleothems, which have been dated with the U-Th series method .()......(Hellstrom, 2003; Scholz and Hoffmann, 2008). Their ages coincide with current and previous two interglacials (MIS 1, 5e and 7e and Greenland interstadials (GIS) 19, 20, 21 and 24. Considering that these periods are amongst the most pronounced warm-wet pulsations over the last 250,000 ...(Martrat et al., 2007; NGRIP, 2004), and that CO2 has a fundamental role in this karst process, this study explores the climate-driven hydrogeological conditions necessary to trigger carbonate deposition in gypsum voids. The further correlation with sapropel events 5, 4, 3 and 1, considered symptomatic of enhanced rainfall across the whole Mediterranean basin .(.)(Emeis et al., 1991), highlights the importance of flow-rate in the fracture network and infiltration of meteoric water into the caves. The combination of high CO2 and a phreatic status of the fracture network is thus indispensable for the formation of carbonate speleothems in gypsum karst. This condition appears to be triggered by periods of orbital precession minimum, when the monsoonal activity peaked in the Atlantic area. Stable oxygen isotope signatures suggest that the speleothems did not grow during any interglacial-glacial or main interstadial-stadial transitions, confirming that variations from optimum climate conditions may hamper the formation of this category of speleothems. New speleological exploration and sampling campaign

  19. Middle to Late Pleistocene coastal deposits of Eivissa (Western Mediterranean): Chronology and evolution.

    NASA Astrophysics Data System (ADS)

    Del Valle, Laura; Pomar, Francisco; Fornós, Joan J.; Gómez-Pujol, Lluís; Anechitei-Deacu, Valentina; Timar-Gabor, Alida

    2016-04-01

    This study deals with the sedimentary and stratigraphical description of Pleistocene deposits from seven coastal areas of Eivissa (Balearic Islands). Twenty two sedimentary facies have been described involving the succession of eolian, colluvial and edaphic environments. Carbonate sandstones, breccias and silty deposits are the main component of these sequences. Despite the extensive eolian systems outcropping along the coast of Eivissa, there are very few studies performed to chronological framework of these deposits. Luminescence measurements were carried out using an automated RisØ TL/OSL-DA-20 reader in the Luminescence Dating Laboratory of Babes-Bolyai University (Cluj-Napoca, Romania) under low intensity red light. OSL dating of nineteen eolian levels indicate that their deposition took place between the Middle and Late Pleistocene, establishing a paleoclimatic evolution of Eivissa Island since 755 ka to 70 Ka. Eolian activity in the Eivissa Island can be correlated with regression episodes which took place during cold periods associated with different isotopic stages, concretely the MIS 18, 16, 12, 10, 8, 6 and 4. Similar results have been obtained from many sites along the western Mediterranean Sea such as Mallorca (Pomar i Cuerda, 1979; Nielsen et al, 2004; Fornós et al, 2009), Sardinia (Andreucci et al, 2009; Pascucci et al, 2014), Liguria (Pappalardo et al., 2013). Keywords: Eolian dunes, Pleistocene, Climatic evolution, Eivissa. References - Andreucci, S.; Pascucci, V.; Murray, A. S.; Clemmensen, L. B. 2009. Late Pleistocene coastal evolution of San Giovanni di Sinis, west Sardinia (Western Mediterranean). Sedimentary Geology, 216: 104- 116 - Fornós, J.J.; Clemmensen, L.B.; Gómez-Pujol, L.; Murray, A. 2009. Late Pleistocene carbonate aeolianites on Mallorca, Western Mediterranean: a luminescence chronology. Quaternary Science reviews 28: 2697-2709. -Nielsen, K.A.; Clemmensen, L.B.; Fornós, J.J. 2004. Middle Pleistocene magnetostratigraphy and

  20. An animated reconstruction of Western Mediterranean tectonics since 19Ma

    NASA Astrophysics Data System (ADS)

    Hames, C. R.; Platt, J. P.

    2010-12-01

    We present tectonic reconstructions and an animation of the deformation around the Alboran Sea (westernmost Mediterranean) from 19 Ma to present. Displacement data were constrained using published kinematic and paleomagnetic data from the external Betic-Rif thrust belt, including linear indicators of slip on thrust surfaces; estimates of shortening determined by restoration of cross sections; and paleomagnetically determined vertical-axis rotations. We use ArcGIS along with Adobe products to organize our data points and create the animations. The Alboran domain moved approximately 250 km westward relative to Iberia and Africa, with convergence directions varying from 310° to 295° on the Iberian side of the arc, and from 235° to 215° on the African side. The difference in direction is primarily a result of relative motion between Iberia and Africa. Extensional collapse of the Alboran domain following Paleogene contractional tectonics led to counter-clockwise rotation of the Internal Rif into its present orientation, and to the development of strike-slip shear zones that transfer differential displacement from within the Alboran Domain into the external thrust belt. These shear zones allowed the limbs of the arc to tighten by rotation and extension, with the Betic sector of the arc rotating clockwise by 25° and the southern Rif rotating counter-clockwise by approximately 55°. Oblique convergence with opposite sense in the two limbs of the arc caused rotation of thrust sheets and other structures by amounts that were substantially larger than the bulk rotation of the limbs of the arc, accompanied by distributed shear in the rear of the thrust wedge. The reconstruction allows visualization of the interaction between the extending Alboran Domain and contractional tectonics in the thrust belt. It also allows quantification of the amount of lithosphere that was subducted or otherwise destroyed during relative motion between the Alboran Domain and the surrounding

  1. Balearic insular isolation and large continental spread framed the phylogeography of the western Mediterranean Cheirolophus intybaceus s.l. (Asteraceae).

    PubMed

    Garnatje, T; Pérez-Collazos, E; Pellicer, J; Catalán, P

    2013-01-01

    Recent Quaternary geological and climate events have shaped the evolutionary histories of plant species in the Mediterranean basin, one of the most important hotspots of biodiversity. Genetic analyses of the western Mediterranean Cheirolophus intybaceus s.l. (Asteraceae) based on AFLP were conducted to establish the relationships between its close species and populations, to reconstruct the phylogeography of the group and to analyse potential unidirectional versus bidirectional dispersals between the Ibero-Provençal belt and the Balearic Islands. AFLP data revealed two main genetic groups, one constituted by the Balearic populations and Garraf (NE Iberia) and the other formed by the remaining mainland populations that were further sub-structured into two geographically separated subgroups (SE + E Iberia and NE Iberia + SW France). Genetic diversity and spatial structure analyses suggested a mid-Pleistocene scenario for the origin of C. intybaceus in southern Iberia, followed by dispersal to the north and a single colonisation event of the Balearic archipelago from the near Dianic NE Iberian area. This hypothesis was supported by paleogeographic data, which showed the existence of terrestrial connections between the continent and the islands during the Middle-Late Pleistocene marine regressions, whereas the more recent single back-colonisation of the mainland from Mallorca might be explained by several hypotheses, such as long-distance dispersal mediated by migratory marine birds or sea currents.

  2. Heat flow in the Alboran Sea, western Mediterranean

    NASA Astrophysics Data System (ADS)

    Polyak, B. G.; Fernàndez, M.; Khutorskoy, M. D.; Soto, J. I.; Basov, I. A.; Comas, M. C.; Khain, V. Ye.; Alonso, B.; Agapova, G. V.; Mazurova, I. S.; Negredo, A.; Tochitsky, V. O.; de la Linde, J.; Bogdanov, N. A.; Banda, E.

    1996-10-01

    The results of the first regional heat flow survey carried out in the Alboran Basin are presented. The survey consists of 98 heat flow measurements obtained using a violin type probe, 697 nautic miles of gravity profiles, 1446 nautic miles of bathymetric survey, and 22 gravity cores. A remarkable difference in heat flow patterns exists between the western (WAB) and eastern (EAB) parts of the Alboran Basin. The average heat flow in the WAB is 69 ± 6 mW m -2 with a generally increasing trend towards the centre and to the east. In contrast, the heat flow pattern in the EAB shows an average value of 124 ± 8 mW m -2 and it is maintained rather constant for the overall area. Superimposed on this general pattern there are some local thermal anomalies, associated with hydrothermal activity, which have been detected in the central WAB (up to 123 mW m -2), in the South Alboran Basin (SAB) (up to 153 mW m -2) and in the Djibouti Bank (DB) (up to 254 mW m -2). After corrections for thermal refraction, sedimentation and cooling of volcanic bodies, the resulting heat flow distribution in the WAB is smoother, but still shows the increasing trend towards the centre and to the east. In the EAB, the application of these corrections did not lead to any noticeable changes. A 1-D approach that combines heat flow data, crustal structure and elevation shows a dramatic decrease in lithospheric thickness from the WAB (50-90 km) to the EAB (38-40 km). Likewise, the resulting crustal thickness is around 14-16 km in the central part of the WAB, increasing towards the borders of the basin, whereas in the EAB the crustal thickness varies between 12.5 and 14.5 km in its western part, and between 10 and 11.5 km in its eastern part.

  3. 30. Photograph looking north from western pool, along the cribs ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    30. Photograph looking north from western pool, along the cribs and channel toward the east forebay. U.S. 24 is on the left, the archaeological overburden windrow is on the right. - Wabash & Erie Canal, Lock No. 2, 8 miles east of Fort Wayne, adjacent to U.S. Route 24, New Haven, Allen County, IN

  4. A Cross Generational Dialect Study in Western North Carolina

    ERIC Educational Resources Information Center

    Holt, Yolanda Feimster

    2011-01-01

    This dissertation evaluates the relationship between African American English and White Vernacular English as spoken in a small rural town in western North Carolina for consistencies in vowel production by group membership and for participation in the Southern Vowel Shift (SVS), a vowel rotation currently occurring in the Southern United States. A…

  5. CHARACTERIZATION OF WESTERN NORTH ATLANTIC RIGHT WHALE SPRING FEEDING HABITAT

    EPA Science Inventory

    The Great South Channel region of the southwestern Gulf of Maine, between George's Bank and Cape Cod, is the primary spring feeding ground for the western North Atlantic population of the I northern right whale, E. glacialis .Since this whale is so endangered, it is critical to i...

  6. Seismic source and structure estimation in the western Mediterranean using a sparse broadband network

    NASA Astrophysics Data System (ADS)

    Thio, Hong Kie; Song, Xi; Saikia, Chandan K.; Helmberger, Donald V.; Woods, Bradley B.

    1999-01-01

    We present a study of regional earthquakes in the western Mediterranean geared toward the development of methodologies and path calibrations for source characterization using regional broadband stations. The results of this study are useful for the monitoring and discrimination of seismic events under a comprehensive test ban treaty, as well as the routine analysis of seismicity and seismic hazard using a sparse array of stations. The area consists of several contrasting geological provinces with distinct seismic properties, which complicates the modeling of seismic wave propagation. We started by analyzing surface wave group velocities throughout the region and developed a preliminary model for each of the major geological provinces. We found variations of crustal thickness ranging from 45 km under the Atlas and Betic mountains and 37 km under the Saharan shield, to 20 km for the oceanic crust of the western Mediterranean Sea, which is consistent with earlier works. Throughout most of the region, the upper mantle velocities are low which is typical for tectonically active regions. The most complex areas in terms of wave propagation are the Betic Cordillera in southern Spain and its north African counterparts, the Rif and Tell Atlas mountains, as well as the Alboran Sea, between Spain and Morocco. The complexity of the wave propagation in these regions is probably due to the sharp velocity contrasts between the oceanic and continental regions as well as the the existence of deep sedimentary basins that have a very strong influence on the surface wave dispersion. We used this preliminary regionalized velocity model to correct the surface wave source spectra for propagation effects which we then inverted for source mechanism. We found that this method, which is in use in many parts of the world, works very well, provided that data from several stations are available. In order to study the events in the region using very few broadband stations or even a single station

  7. Size distribution and optical properties of mineral dust aerosols transported in the western Mediterranean

    NASA Astrophysics Data System (ADS)

    Denjean, C.; Cassola, F.; Mazzino, A.; Triquet, S.; Chevaillier, S.; Grand, N.; Bourrianne, T.; Momboisse, G.; Sellegri, K.; Schwarzenbock, A.; Freney, E.; Mallet, M.; Formenti, P.

    2015-08-01

    This study presents in situ aircraft measurements of Saharan mineral dust transported over the western Mediterranean basin in June-July 2013 during the ChArMEx/ADRIMED (the Chemistry-Aerosol Mediterranean Experiment/Aerosol Direct Radiative Impact on the regional climate in the MEDiterranean region) airborne campaign. Dust events differing in terms of source region (Algeria, Tunisia and Morocco), time of tranport (1-5 days) and height of transport were sampled. Mineral dust were transported above the marine boundary layer, which conversely was dominated by pollution and marine aerosols. The dust vertical structure was extremely variable and characterized by either a single layer or a more complex and stratified structure with layers originating from different source regions. Mixing of mineral dust with pollution particles was observed depending on the height of transport of the dust layers. Dust layers carried higher concentration of pollution particles at intermediate altitude (1-3 km) than at elevated altitude (> 3 km), resulting in scattering Angstrom exponent up to 2.2 within the intermediate altitude. However, the optical properties of the dust plumes remained practically unchanged with respect to values previously measured over source regions, regardless of the altitude. Moderate light absorption of the dust plumes was observed with values of aerosol single scattering albedo at 530 nm ranging from 0.90 to 1.00 ± 0.04. Concurrent calculations from the aerosol chemical composition revealed a negligible contribution of pollution particles to the absorption properties of the dust plumes that was due to a low contribution of refractory black carbon in regards to the fraction of dust and sulfate particles. This suggests that, even in the presence of moderate pollution, likely a persistent feature in the Mediterranean, the optical properties of the dust plumes could be assimilated to those of native dust in radiative transfer simulations, modeling studies and

  8. Size distribution and optical properties of mineral dust aerosols transported in the western Mediterranean

    NASA Astrophysics Data System (ADS)

    Denjean, C.; Cassola, F.; Mazzino, A.; Triquet, S.; Chevaillier, S.; Grand, N.; Bourrianne, T.; Momboisse, G.; Sellegri, K.; Schwarzenbock, A.; Freney, E.; Mallet, M.; Formenti, P.

    2016-02-01

    This study presents in situ aircraft measurements of Saharan mineral dust transported over the western Mediterranean basin in June-July 2013 during the ChArMEx/ADRIMED (the Chemistry-Aerosol Mediterranean Experiment/Aerosol Direct Radiative Impact on the regional climate in the MEDiterranean region) airborne campaign. Dust events differing in terms of source region (Algeria, Tunisia and Morocco), time of transport (1-5 days) and height of transport were sampled. Mineral dust were transported above the marine boundary layer, which conversely was dominated by pollution and marine aerosols. The dust vertical structure was extremely variable and characterized by either a single layer or a more complex and stratified structure with layers originating from different source regions. Mixing of mineral dust with pollution particles was observed depending on the height of transport of the dust layers. Dust layers carried a higher concentration of pollution particles below 3 km above sea level (a.s.l.) than above 3 km a.s.l., resulting in a scattering Ångström exponent up to 2.2 below 3 km a.s.l. However, the optical properties of the dust plumes remained practically unchanged with respect to values previously measured over source regions, regardless of the altitude. Moderate absorption of light by the dust plumes was observed with values of aerosol single scattering albedo at 530 nm ranging from 0.90 to 1.00. Concurrent calculations from the aerosol chemical composition revealed a negligible contribution of pollution particles to the absorption properties of the dust plumes that was due to a low contribution of refractory black carbon in regards to the fraction of dust and sulfate particles. This suggests that, even in the presence of moderate pollution, likely a persistent feature in the Mediterranean, the optical properties of the dust plumes could be assumed similar to those of native dust in radiative transfer simulations, modelling studies and satellite retrievals

  9. The east-west-north colonization history of the Mediterranean and Europe by the coastal plant Carex extensa (Cyperaceae).

    PubMed

    Escudero, M; Vargas, P; Arens, P; Ouborg, N J; Luceño, M

    2010-01-01

    Coastal plants are ideal models for studying the colonization routes of species because of the simple linear distributions of these species. Carex extensa occurs mainly in salt marshes along the Mediterranean and European coasts. Variation in cpDNA sequences, amplified fragment length polymorphisms (AFLPs) and simple sequence repeats (SSRs) of 24 populations were analysed to reconstruct its colonization history. Phylogenetic relationships indicate that C. extensa together with the South American Carex vixdentata and the southern African Carex ecklonii form a monophyletic group of halophilic species. Analyses of divergence times suggest that early lineage diversification may have occurred between the late Miocene and the late Pliocene (Messinian crisis). Phylogenetic and network analyses of cpDNA variation revealed the monophyly of the species and an ancestral haplotype contained in populations of the eastern Mediterranean. The AFLP and SSR analyses support a pattern of variation compatible with these two lineages. These analyses also show higher levels of genetic diversity and differentiation in the eastern population group, which underwent an east-to-west Mediterranean colonization. Quaternary climatic oscillations appear to have been responsible for the split between these two lineages. Secondary contacts may have taken place in areas near the Ligurian Sea in agreement with the gene flow detected in Corsican populations. The AFLP and SSR data accord with the 'tabula rasa' hypothesis in which a recent and rapid colonization of northern Europe took place from the western Mediterranean after the Last Glacial Maximum. The unbalanced west-east vs. west-north colonization may be as a result of 'high density blocking' effect.

  10. The influence of wind direction on the capture of the wood warbler (Phylloscopus sibilatrix), an uncommon migratory species in the western Mediterranean.

    PubMed

    Barriocanal, Carles; Montserrat, David; Robson, David

    2011-11-01

    The wood warbler (Phylloscopus sibilatrix) is a migratory species in the western Mediterranean wintering in the Gulf of Guinea region, West Africa. In autumn and spring, this species, along with the populations breeding in Ireland and Britain, uses the Italian peninsula as its main axis of migration. From the data of captured birds at several ringing stations in the western Mediterranean (Balearic Islands and coastal Iberian Peninsula), we analyzed capture rates of the species during spring migration from 1993 to 2007. Based on the selection of days with a significant number of captures and those without captures, we analyzed the effect of wind direction over the western Mediterranean to determine a relationship between winds and the number of captures. From a total of 663 wood warblers captured between 1993 and 2007, a total of 31 days have been selected as significant days with a high number of captures, and 31 days have been selected as no-capture days. On days of maximum captures, winds coming from an easterly direction, i.e. Algeria and Tunisia, were dominant, indicating days with a clear eastern component. Contrary to expected results, captures were also made on days when the wind direction was predominantly from a northerly direction. Analysis of the origin of the winds in north eastern Spain (western Mediterranean) revealed that the majority of northerly winds originated from Africa and not from Europe as is usual for this region. Days or periods selected as no-capture days were characterized by winds coming from a northerly (European origin) or westerly direction.

  11. [Proof of the indigenous nature of Populus alba L. in the western Mediterranean Basin].

    PubMed

    Roiron, Paul; Ali, Adam A; Guendon, Jean-Louis; Carcaillet, Christopher; Terral, Jean-Frédéric

    2004-02-01

    Around the western Mediterranean Basin, the ecological status of Populus alba, whether indigenous or introduced, is controversial. This note presents new palaeobotanical data based on analyses of leaf imprints from a travertine formation located in southern France. This travertine presents two levels with Populus alba imprints. The oldest level is dated back by 14C to the Early Holocene, i.e., 8890 +/- 70 BP. This demonstrates that Populus alba is an autochthonous species of the southern-France vegetation, removing speculations reporting that its distribution area was greatly influenced by Roman civilization. Finally, we discuss this new data in regard to other Pleistocene and Holocene deposits circum the Mediterranean Basin and in Europe, where this species was identified. PMID:15060983

  12. Chemical contamination baseline in the Western basin of the Mediterranean Sea based on transplanted mussels.

    PubMed

    Andral, Bruno; Galgani, François; Tomasino, Corinne; Bouchoucha, Marc; Blottiere, Charlotte; Scarpato, Alfonso; Benedicto, José; Deudero, Salud; Calvo, Monica; Cento, Alexandro; Benbrahim, Samir; Boulahdid, Moustapha; Sammari, Cherif

    2011-08-01

    The MYTILOS project aimed at drawing up a preliminary report on coastal chemical contamination at the scale of the Western Mediterranean (continental coasts of the Balearic Islands, Sicily, Sardinia, Corsica and Maghreb) based on a transplanted mussels methodology validated along the French coasts since 1996 by Ifremer and the Rhône Méditerranée & Corsica water board. MYTILOS is backed up by the INTERREG III B/MEDOC programme, the PNUE/PAM-MEDPOL and Rhône Méditerranée & Corsica water board. Three cruises (2004, 2005, 2006) have taken place to assess the first state of chemical contamination along the Western Mediterranean shores with the same methodology. Approximately 120 days were spent at sea deploying and retrieving 123 mussel bags. The results obtained for all studied contaminants were equivalent to those obtained along the French coast according the RINBIO network. These similarities relate to both the highest measured levels and background levels throughout the 123 stations. The areas of greatest impact were mainly urban and industrial centers and the outlets of major rivers, with a far higher midsea impact on the dilution of organic compounds than on metals. Metal levels measured in midsea zones were found to be similar to those in natural shellfish populations living along the coast. On a global scale we can observe that the contaminants levels in the Mediterranean Sea are in the same range as in other areas worldwide. Overall, the research demonstrates the reliability of this methodology for marine pollution monitoring, especially in the Mediterranean sea. PMID:20862467

  13. The role of North African rivers in driving Mediterranean-Atlantic exchange

    NASA Astrophysics Data System (ADS)

    Flecker, Rachel; Marzocchi, Alice; van der Schee, Marlies; Meijer, Paul; Lofi, Johanna; Lunt, Dan

    2014-05-01

    The main driver for exchange through the Gibraltar Strait today is the density contrast between Mediterranean and Atlantic water. Mediterranean water is more saline than Atlantic water because the amount of water the Mediterranean loses through evaporation exceeds both precipitation and freshwater input from rivers. This means it has a negative hydrologic budget. In the Late Miocene however, a very large river known as the Esohabi River drained across North Africa and had its mouth in the Gulf of Sirt. This river was sourced in palaeo-Lake Chad and was strongly influenced by precession-driven monsoonal rainfall. Multiple General Circulation Model simulations through a single precessional cycle indicate that river water may only have reached the Mediterranean in significant quantities in summer during particular orbital configurations e.g. precession minima combined with eccentricity maxima. However, during high amplitude eccentricity maxima, the volume of water supplied through the Esohabi and Nile rivers may have been sufficient to switch the hydrologic budget from negative to positive. In doing so, the fresh water supply should have reduced the salinity of the Mediterranean and consequently the density contrast with adjacent Atlantic water leading to a reduction in exchange. In this presentation we explore the evidence for the timing and nature of freshwater input to the Mediterranean from North Africa. We also consider how relevant this freshwater flux may be in determining some of the major environmental and sedimentological changes in the Late Miocene to early Pliocene including some of the salinity changes that occurred during the Messinian Salinity Crisis.

  14. The two main steps of the Atlas building and geodynamics of the western Mediterranean

    NASA Astrophysics Data System (ADS)

    de Lamotte, Dominique Frizon; Bezar, Bertrand Saint; Bracène, Rabah; Mercier, Eric

    2000-08-01

    The Atlas system (Morocco, Algeria, and Tunisia) constitutes an important morphologic barrier fringing the Sahara platform. Its structural style changes along strike from a thick-skinned style in Morocco to a thin-skinned one in Algeria and Tunisia. The position relative to the Tell-Rif system is also different in eastern Algeria and Tunisia where the two systems are adjacent and in western Algeria and Morocco where they are separated by large rigid cores (Moroccan Meseta and Algerian High Plateaux). New data, as well as a reappraisal of available data, show that the Atlas build up occurred everywhere during two main phases of late Eocene and Pleistocene-lower Quaternary age, respectively. These phases are clearly distinct and do not represent end points of a progressive deformation. An additional Tortonian event exists in the eastern region where the Tell-Rif is thrusting directly over the Atlas. From Oligocene to middle Miocene the development of the Tell-Rif accretionary prism is coeval to subduction rollback of Maghrebian Tethys lithosphere and related to the opening of the western Mediterranean Sea. For kinematic and chronological reasons this process cannot account for the two specific steps of the Atlas building. They are better explained assuming that they record two jolts in the convergence of Africa with respect to Europe and correspond roughly to the initiation and the cessation of the subduction processes active in the western Mediterranean region.

  15. Direct ageing of Thunnus thynnus from the eastern Atlantic Ocean and western Mediterranean Sea using dorsal fin spines.

    PubMed

    Luque, P L; Rodriguez-Marin, E; Landa, J; Ruiz, M; Quelle, P; Macias, D; Ortiz De Urbina, J M

    2014-06-01

    This study deals with important methodology issues that affect age estimates of eastern Atlantic bluefin tuna Thunnus thynnus using dorsal fin spines. Nearly 3800 spine sections were used from fish caught in the north-east Atlantic Ocean and western Mediterranean Sea over a 21 year period. Edge type and marginal increment analyses indicated a yearly periodicity of annulus formation with the translucent bands (50% of occurrence) appearing from October to May. Nucleus vascularization seriously affected specimens older than 6 years, with the disappearance of 40-50% of the presumed annuli by that age. An alternate sectioning location was a clear improvement and this finding is an important contribution to the methodology of using this structure for ageing the full-length range of eastern T. thynnus. Finally, there were no significant differences between the coefficients of von Bertalanffy growth model estimated from mean length at age data (L∞  = 327.4; k = 0.097; t0  = -0.838) and those estimated from the growth curves accepted for the eastern and western T. thynnus management units. PMID:24890407

  16. Nutrient and trace metals atmospheric deposition in the western Mediterranean: source apportionment

    NASA Astrophysics Data System (ADS)

    Desboeufs, Karine; Bon Nguyen, Elisabeth; Simeoni, Pasquale; Dulac, François

    2015-04-01

    Mediterranean Sea is a typical LNLC region particularly well adapted to assess the role of ocean-atmosphere exchanges. Throughout the summer stratification period when diffusion through the thermocline is low, atmospheric inputs become the main external source of nutrients to the surface open waters of the MS, mostly by wet deposition in the western basin.Here, we show a 3-yr time continuous series of nutrient (N, P) and trace metals (Cr, Cu, Fe, P, V, Zn) total deposition fluxes in Corsica. Between March 2008 and May 2011, a monitoring station was operated with a weekly sampling time step at Galeria (42.44°N; 8.65°E) on the western coast of Corsica in the framework of the projects DUNE (a Dust Experiment in a Low Nutrient Low Chlorophyll Ecosystem) and then ChArMEx (the Chemistry-Aerososl Mediterranean Experiment). Monthly fluxes were measured to assess the temporal variability of the measured elements over the Western Mediterranean. Nutrients deposition presented a clear seasonal pattern which was different for each studied nutrients, emphasizing a difference of sources for the nutrients. The results show no dust event larger than 0.68 g m-2 so that the maximum yearly flux was among the lowest ever observed in Corsica (1.7 g m-2 y-1). One dust deposition event could contribute up to 30% of yearly deposition fluxes of nutrient and trace metals, confirming the high temporal variability of atmospheric deposition. However a source apportionment work via statistical methods shows that the yearly deposition fluxes of considered nutrient and trace metals were dominated by anthropogenic sources, except for Fe. Acknowledgements: DUNE project was funded by ANR. ChArMEx (http://charmex.lsce.ipsl.fr) is funded by CNRS/INSU, ADEME, CEA and Météo-France in the framework of the programme MISTRALS (http://www.mistrals-home.org)

  17. Origin of fine carbonaceous particulate matter in the Western Mediterranean Basin: fossil versus modern sources

    NASA Astrophysics Data System (ADS)

    Cruz Minguillón, María.; Perron, Nolwenn; Querol, Xavier; Szidat, Sönke; Fahrni, Simon; Wacker, Lukas; Reche, Cristina; Cusack, Michael; Baltensperger, Urs; Prévôt, André S. H.

    2010-05-01

    The present work was carried out in the frame of the international field campaign DAURE (Determination of the sources of atmospheric Aerosols in Urban and Rural Environments in the western Mediterranean). The objective of this campaign is to study the aerosol pollution episodes occurring at regional scale during winter and summer in the Western Mediterranean Basin. As part of this campaign, this work focuses on identifying the origin of fine carbonaceous aerosols. To this end, fine particulate matter (PM1) samples were collected during two different seasons (February-March and July 2009) at two sites: an urban site (Barcelona, NE Spain) and a rural European Supersite for Atmospheric Aerosol Research (Montseny, NE Spain). Subsequently, 14C analyses were carried out on these samples, both in the elemental carbon (EC) fraction and the organic carbon (OC) fraction, in order to distinguish between modern carbonaceous sources (biogenic emissions and biomass burning emissions) and fossil carbonaceous sources (mainly road traffic). Preliminary results from the winter period show that 40% of the OC at Barcelona has a fossil origin whereas at Montseny this percentage is 30%. These values can be considered as unexpected given the nature of the sites. Nevertheless, the absolute concentrations of fossil OC at Barcelona and Montseny differ by a factor of 2 (the first being higher), since the total OC at Montseny is lower than at Barcelona. Further evaluation of results and comparison with other measurements carried out during the campaign are required to better evaluate the origin of the fine carbonaceous matter in the Western Mediterranean Basin. Acknowledgements: Spanish Ministry of Education and Science, for a Postdoctoral Grant awarded to M.C. Minguillón in the frame of Programa Nacional de Movilidad de Recursos Humanos del Plan nacional de I-D+I 2008-2011. Spanish Ministry of Education and Science, for the Acción Complementaria DAURE CGL2007-30502-E/CLI.

  18. Bird migration routes and risk for pathogen dispersion into western Mediterranean wetlands.

    PubMed

    Jourdain, Elsa; Gauthier-Clerc, Michel; Bicout, Dominique J; Sabatier, Philippe

    2007-03-01

    Wild birds share with humans the capacity for moving fast over large distances. During migratory movements, birds carry pathogens that can be transmitted between species at breeding, wintering, and stopover places where numerous birds of various species are concentrated. We consider the area of the Camargue (southern France) as an example to highlight how ad hoc information already available on birds' movements, abundance, and diversity can help assess the introduction and transmission risk for birdborne diseases in the western Mediterranean wetlands. Avian influenza and West Nile viruses are used as examples because birds are central to the epidemiology of these viruses. PMID:17552088

  19. Bird migration routes and risk for pathogen dispersion into western Mediterranean wetlands.

    PubMed

    Jourdain, Elsa; Gauthier-Clerc, Michel; Bicout, Dominique J; Sabatier, Philippe

    2007-03-01

    Wild birds share with humans the capacity for moving fast over large distances. During migratory movements, birds carry pathogens that can be transmitted between species at breeding, wintering, and stopover places where numerous birds of various species are concentrated. We consider the area of the Camargue (southern France) as an example to highlight how ad hoc information already available on birds' movements, abundance, and diversity can help assess the introduction and transmission risk for birdborne diseases in the western Mediterranean wetlands. Avian influenza and West Nile viruses are used as examples because birds are central to the epidemiology of these viruses.

  20. Trends in Western North Pacific Tropical Cyclone Intensity

    NASA Astrophysics Data System (ADS)

    Wu, Man-Chi; Yeung, Kai-Hing; Chang, Wen-Lam

    2006-11-01

    Using the tropical cyclone best track data from the U.S. Department of Defense's Joint Typhoon Warning Center (JTWC), Webster et al. found that between the two consecutive 15-year periods of 1975-1989 and 1990-2004, the percentage of typhoons in the western North Pacific meeting the definition of categories 4 and 5 on the Saffir-Simpson Hurricane Scale has increased from 25% to 41% of all typhoons in that ocean basin

  1. A magmatic probe of dynamic topography beneath western North America

    NASA Astrophysics Data System (ADS)

    Klöcking, M.; White, N. J.; Maclennan, J.

    2014-12-01

    A region centered on the Yellowstone hotspot and encompassing the Colorado Plateau sits at an elevation 2 km higher than the cratonic North America. This difference broadly coincides with tomographically observed variations in lithospheric thickness: ~120 km beneath western North America, ~240 km beneath the craton. Thermochronology of the Grand Canyon area, sedimentary flux to the Gulf of Mexico, and river profile inversion all suggest that regional uplift occurred in at least two separate stages. High resolution seismic tomographic models, using USArray data, have identified a ring of low velocity material beneath the edges of the Colorado Plateau. Magmatism coincides with these low velocity zones and shows distinct phases: an overall increase in volume around 40 Ma and a change from lithospheric to asthenospheric signatures around 5 Ma. Volcanism is also observed to migrate north-east with time. Here, we attempt to integrate these different observations with lithospheric thickness. A dynamic topography model of progressive lithospheric erosion over a hot mantle plume might account for uplift as well as the temporal and spatial distribution of magmatism across western North America. Thinning of the lithosphere around the edges of the Colorado Plateau in combination with the hotter mantle potential temperature of a plume could create isostatic and dynamic uplift as well as allowing for melt production. To test this model, we have analysed around 100 samples from volcanic centers across western North America by ICP-MS for rare earth elements (REE). Most of the samples are younger than 5 Ma, and all of them have previously been analysed by XRF. Using trace element ratios such as La/Yb and Nb/Y we assess depth of melting and melt fraction, respectively. In addition, we use REE inversion modelling to estimate melt fractions as a function of depth and temperature of melting. The results are compared to existing constraints on lithospheric thickness and mantle potential

  2. Changes toward earlier streamflow timing across western North America

    USGS Publications Warehouse

    Stewart, I.T.; Cayan, D.R.; Dettinger, M.D.

    2005-01-01

    The highly variable timing of streamflow in snowmelt-dominated basins across western North America is an important consequence, and indicator, of climate fluctuations. Changes in the timing of snowmelt-derived streamflow from 1948 to 2002 were investigated in a network of 302 western North America gauges by examining the center of mass for flow, spring pulse onset dates, and seasonal fractional flows through trend and principal component analyses. Statistical analysis of the streamflow timing measures with Pacific climate indicators identified local and key large-scale processes that govern the regionally coherent parts of the changes and their relative importance. Widespread and regionally coherent trends toward earlier onsets of springtime snowmelt and streamflow have taken place across most of western North America, affecting an area that is much larger than previously recognized. These timing changes have resulted in increasing fractions of annual flow occurring earlier in the water year by 1-4 weeks. The immediate (or proximal) forcings for the spatially coherent parts of the year-to-year fluctuations and longer-term trends of streamflow timing have been higher winter and spring temperatures. Although these temperature changes are partly controlled by the decadal-scale Pacific climate mode [Pacific decadal oscillation (PDO)], a separate and significant part of the variance is associated with a springtime warming trend that spans the PDO phases. ?? 2005 American Meteorological Society.

  3. Characterization of a Strain of Fukuyoa paulensis (Dinophyceae) from the Western Mediterranean Sea.

    PubMed

    Laza-Martínez, Aitor; David, Helena; Riobó, Pilar; Miguel, Irati; Orive, Emma

    2016-07-01

    A single cell of the dinoflagellate genus Fukuyoa was isolated from the island of Formentera (Balearic Islands, west Mediterranean Sea), cultured, and characterized by morphological and molecular methods and toxin analyses. This is the first report of the Gambierdiscus lineage (genera Fukuyoa and Gambierdiscus) from the western Mediterranean Sea, which is cooler than its eastern basin. Molecular analyses revealed that the Mediterranean strain belongs to F. paulensis and that it bears LSU rDNA sequences identical to New Zealand, Australian, and Brazilian strains. It also shared an identical sequence of the more variable ITS-rDNA with the Brazilian strain. Toxin analyses showed the presence of maitotoxin, 54-deoxyCTX1B, and gambieric acid A. This is the first observation of the two latter compounds in a Fukuyoa strain. Therefore, both Gambierdiscus and Fukuyoa should be considered when as contributing to ciguatera fish poisoning. Different strains of Fukuyoa form a complex of morphologically cryptic lineages where F. paulensis stands as the most distantly related nominal species. The comparison of the ITS2 secondary structures revealed the absence of CBCs among strains. The study of the morphological and molecular traits depicted an unresolved taxonomic scenario impacted by the low strains sampling. PMID:26686980

  4. Regional genetic differentiation among populations of Cladocora caespitosa in the Western Mediterranean

    NASA Astrophysics Data System (ADS)

    Casado-Amezúa, Pilar; Kersting, Diego K.; Templado, José; Machordom, Annie

    2014-12-01

    Cladocora caespitosa is the only reef-forming zooxanthellate scleractinian in the Mediterranean Sea. This endemic coral has suffered severe mortality events at different Mediterranean sites owing to anomalous summer heat waves related to global climate change. In this study, we assessed genetic structure and gene flow among four populations of this species in the Western Mediterranean Sea: Cape Palos (SE Spain), Cala Galdana (Balearic Islands), Columbretes Islands, and L'Ametlla (NE Spain). The results obtained from Bayesian approaches, F ST statistics, and Bayesian analysis of migration rates suggest certain levels of genetic differentiation driven by high levels of self-recruitment, a fact that is supported by egg-retention mechanisms. Conversely, genetic connectivity among distant populations, even if generally low, seems to be related to sporadic dispersal events through regional surface currents linked to the spawning period that occurs at the end of summer-beginning of autumn. These features, together with a certain isolation of the Columbretes Islands, could explain the regional genetic differentiation found among populations. These results help to better understand population structure and connectivity of the species and will serve as an approach for further studies on different aspects of the biology and ecology of C. caespitosa.

  5. Marine debris ingestion in loggerhead sea turtles, Caretta caretta, from the Western Mediterranean.

    PubMed

    Tomás, J; Guitart, R; Mateo, R; Raga, J A

    2002-03-01

    Marine debris represents an important threat for sea turtles, but information on this topic is scarce in some areas, such as the Mediterranean sea. This paper quantifies marine debris ingestion in 54 juvenile loggerhead sea turtles (Caretta caretta) illegally captured by fishermen in Spanish Mediterranean waters. Curved carapace length was measured, necropsies were performed and debris abundance and type was recorded. Different types of debris appeared in the gastrointestinal tract of 43 turtles (79.6%), being plastics the most frequent (75.9%). Tar, paper, Styrofoam, wood, reed, feathers, hooks, lines, and net fragments were also present. A regression analysis showed that the volume of debris increased proportionally to the size of the turtles. The high variety of debris found and the large differences in ingestion among turtles indicated low feeding discrimination of this species that makes it specially prone to debris ingestion. Our data suggest that more severe control of litter spills and greater promotion of environmental educational programmes are needed in the Western Mediterranean.

  6. Characterization of a Strain of Fukuyoa paulensis (Dinophyceae) from the Western Mediterranean Sea.

    PubMed

    Laza-Martínez, Aitor; David, Helena; Riobó, Pilar; Miguel, Irati; Orive, Emma

    2016-07-01

    A single cell of the dinoflagellate genus Fukuyoa was isolated from the island of Formentera (Balearic Islands, west Mediterranean Sea), cultured, and characterized by morphological and molecular methods and toxin analyses. This is the first report of the Gambierdiscus lineage (genera Fukuyoa and Gambierdiscus) from the western Mediterranean Sea, which is cooler than its eastern basin. Molecular analyses revealed that the Mediterranean strain belongs to F. paulensis and that it bears LSU rDNA sequences identical to New Zealand, Australian, and Brazilian strains. It also shared an identical sequence of the more variable ITS-rDNA with the Brazilian strain. Toxin analyses showed the presence of maitotoxin, 54-deoxyCTX1B, and gambieric acid A. This is the first observation of the two latter compounds in a Fukuyoa strain. Therefore, both Gambierdiscus and Fukuyoa should be considered when as contributing to ciguatera fish poisoning. Different strains of Fukuyoa form a complex of morphologically cryptic lineages where F. paulensis stands as the most distantly related nominal species. The comparison of the ITS2 secondary structures revealed the absence of CBCs among strains. The study of the morphological and molecular traits depicted an unresolved taxonomic scenario impacted by the low strains sampling.

  7. Invasion by a Japanese marine microorganism in western North America

    USGS Publications Warehouse

    McGann, M.; Sloan, D.; Cohen, A.N.

    2000-01-01

    The earliest record in western North America of Trochammina hadai Uchio, a benthic foraminifer common in Japanese estuaries, is from sediment collected in Puget Sound in 1971. It was first found in San Francisco Bay in sediment samples taken in 1983, and since 1986 has been collected at 91% of the sampled sites in the Bay, constituting up to 93% of the foraminiferal assemblage at individual sites. The species is also present in recent sediment samples from 12 other sites along the west coast of North America. The evidence indicates that T. hadai is a recent introduction to San Francisco Bay, and is probably also not native to the other North American sites. Trochammina hadai was probably transported from Japan in ships' ballast tanks, in mud associated with anchors, or in sediments associated with oysters imported for mariculture. Its remarkable invasion of San Francisco Bay suggests the potential for massive, rapid invasions by other marine microorganisms.

  8. The mantle flow field beneath western North America.

    PubMed

    Silver, P G; Holt, W E

    2002-02-01

    Although motions at the surface of tectonic plates are well determined, the accompanying horizontal mantle flow is not. We have combined observations of surface deformation and upper mantle seismic anisotropy to estimate this flow field for western North America. We find that the mantle velocity is 5.5 +/- 1.5 centimeters per year due east in a hot spot reference frame, nearly opposite to the direction of North American plate motion (west-southwest). The flow is only weakly coupled to the motion of the surface plate, producing a small drag force. This flow field is probably due to heterogeneity in mantle density associated with the former Farallon oceanic plate beneath North America. PMID:11834831

  9. Integrated survey of elemental stoichiometry (C, N, P) from the Western to Eastern Mediterranean Sea

    NASA Astrophysics Data System (ADS)

    Pujo-Pay, M.; Conan, P.; Oriol, L.; Cornet-Barthaux, V.; Falco, C.; Ghiglione, J.-F.; Goyet, C.; Moutin, T.; Prieur, L.

    2010-10-01

    This paper provides an extensive vertical and longitudinal description of the biogeochemistry in the whole Mediterranean Sea during the summer 2008. During this strong stratified period, the distribution of nutrients, particulate and dissolved organic carbon (DOC), nitrogen (DON) and phosphorus (DOP) were investigated along a 3000 km transect (BOUM cruise) crossing the Western and Eastern Mediterranean basins. The partitioning of chemical C, N and P species among all these mineral and organic pools has been analysed to produce a detailed spatial and vertical extended examination of the elemental stoichiometry. Surface Mediterranean waters were depleted in nutrients and the thickness of this depleted layer increased towards the East from about 10 m in the Gulf of Lion to more than 100 m in the Levantine basin, concomitantly to the gradual deepening of the thermocline and nutriclines. We used threshold in oxygen concentration to discriminate the water column in three layers; surface (Biogenic Layer BL), intermediate (Mineralization Layer ML), and deep layer (DL) and to propose a schematic representation of biogeochemical fluxes between the different compartments and to compare the functioning of the two basins. The stoichiometry revealed a clear longitudinal and vertical gradient in the mineral fraction with a P-depletion evidenced on both dimension. As a consequence of the severe deficiency in phosphorus, the C:N:P ratios in all pools within the BL largely exceed the Redfield ratios. Despite these gradients, the deep estimated fluxes in the mineral compartment tend towards the canonical Redfield values in both basins. A change in particulate matter composition has been evidenced by a C increase relative to N and P along the whole water column in the western basin and between BL and ML in the eastern one. More surprisingly, a decrease in N relative to P with depth was encountered in the whole Mediterranean Sea. We suggest that there was a more rapid recycling of N

  10. Patterns of genetic diversity in Hepatozoon spp. infecting snakes from North Africa and the Mediterranean Basin.

    PubMed

    Tomé, Beatriz; Maia, João P; Salvi, Daniele; Brito, José C; Carretero, Miguel A; Perera, Ana; Meimberg, Harald; Harris, David James

    2014-03-01

    Species of Hepatozoon Miller, 1908 are blood parasites most commonly found in snakes but some have been described from all tetrapod groups and a wide variety of hematophagous invertebrates. Previous studies have suggested possible associations between Hepatozoon spp. found in predators and prey. Particularly, some saurophagous snakes from North Africa and the Mediterranean region have been found to be infected with Hepatozoon spp. similar to those of various sympatric lizard hosts. In this study, we have screened tissue samples of 111 North African and Mediterranean snakes, using specific primers for the 18S rRNA gene. In the phylogenetic analysis, the newly-generated Hepatozoon spp. sequences grouped separately into five main clusters. Three of these clusters were composed by Hepatozoon spp. also found in snakes and other reptiles from the Mediterranean Basin and North Africa. In the other two clusters, the new sequences were not closely related to geographically proximate known sequences. The phylogeny of Hepatozoon spp. inferred here was not associated with intermediate host taxonomy or geographical distribution. From the other factors that could explain these evolutionary patterns, the most likely seems series of intermediate hosts providing similar ribotypes of Hepatozoon and a high prevalence of host shifts for Hepatozoon spp. This is indicated by ribotypes of high similarity found in different reptile families, as well as by divergent ribotypes found in the same host species. This potentially low host specificity has profound implications for the systematics of Hepatozoon spp.

  11. Patterns of genetic diversity in Hepatozoon spp. infecting snakes from North Africa and the Mediterranean Basin.

    PubMed

    Tomé, Beatriz; Maia, João P; Salvi, Daniele; Brito, José C; Carretero, Miguel A; Perera, Ana; Meimberg, Harald; Harris, David James

    2014-03-01

    Species of Hepatozoon Miller, 1908 are blood parasites most commonly found in snakes but some have been described from all tetrapod groups and a wide variety of hematophagous invertebrates. Previous studies have suggested possible associations between Hepatozoon spp. found in predators and prey. Particularly, some saurophagous snakes from North Africa and the Mediterranean region have been found to be infected with Hepatozoon spp. similar to those of various sympatric lizard hosts. In this study, we have screened tissue samples of 111 North African and Mediterranean snakes, using specific primers for the 18S rRNA gene. In the phylogenetic analysis, the newly-generated Hepatozoon spp. sequences grouped separately into five main clusters. Three of these clusters were composed by Hepatozoon spp. also found in snakes and other reptiles from the Mediterranean Basin and North Africa. In the other two clusters, the new sequences were not closely related to geographically proximate known sequences. The phylogeny of Hepatozoon spp. inferred here was not associated with intermediate host taxonomy or geographical distribution. From the other factors that could explain these evolutionary patterns, the most likely seems series of intermediate hosts providing similar ribotypes of Hepatozoon and a high prevalence of host shifts for Hepatozoon spp. This is indicated by ribotypes of high similarity found in different reptile families, as well as by divergent ribotypes found in the same host species. This potentially low host specificity has profound implications for the systematics of Hepatozoon spp. PMID:24563141

  12. Monitoring the mesoscale circulation of the Western Mediterranean Sea using SSS derived from SMOS

    NASA Astrophysics Data System (ADS)

    Olmedo, Estrella; Isern-Fontanet, Jordi; Turiel, Antonio; Portabella, Marcos; Ballabrera-Poy, Joaquim

    2016-04-01

    The circulation in the Mediterranean Sea is characterized by the inflow of fresh waters from the Atlantic Ocean through the Strait of Gibraltar. These waters, characterized by their lower salinity, create baroclinic instabilities that spawn eddies with sizes of the order of 100 km. These eddies have been widely analyzed using Sea Surface Temperature (SST) observations. Recent improvements in the Sea Surface Salinity (SSS) retrieval and bias correction methodologies applied to the Soil Moisture and Ocean Salinity (SMOS) satellite data have led, for the first time, to the generation of SSS maps that capture the signature of these structures. This opens the door for the generation of high spatial and temporal density maps in the Mediterranean, which can be used in a wide variety of oceanographic applications. In particular, the signature of the Alboran gyre and the eddy propagation across the Algerian coast are well reproduced, allowing for the first time to characterize the baroclinicity of the flow. The SMOS data are strongly affected by Radio Frequency Interference (RFI) and land-sea contamination in the Mediterranean Sea. Two important SSS retrieval algorithm improvements are proposed in this study. First, with more than six years of SMOS data acquisitions, there is enough data to empirically characterize and correct systematic biases. Second, the filtering criterion has been modified to account for the statistical distributions of SSS at each ocean grid point. This allows retrieving a value of SSS which is less affected by outliers originated from RFI and other effects. In this study, high level (spatio-temporally consistent) SSS maps are obtained by averaging the SMOS SSS retrievals using a classical objective analysis scheme and then combining the resulting maps with Sea Surface Temperature (SST) maps by means of multifractal fusion. The SSS fused maps contain well-defined spatial structures, suitable for studying the mesoscale activity in the Western

  13. Assessment and intercomparison of numerical simulations in the Western Mediterranean Sea

    NASA Astrophysics Data System (ADS)

    Juza, Mélanie; Mourre, Baptiste; Renault, Lionel; Tintoré, Joaquin

    2014-05-01

    The Balearic Islands Coastal Observing and Forecasting System (SOCIB, www.socib.es) is developing high resolution numerical simulations (hindcasts and forecasts) in the Western Mediterranean Sea (WMOP). WMOP uses a regional configuration of the Regional Ocean Modelling System (ROMS, Shchepetkin and McWilliams, 2005) with a high spatial resolution of 1/50º (1.5-2km). Thus, theses simulations are able to reproduce mesoscale and in some cases sub-mesoscale features that are key in the Mediterranean Sea since they interact and modify the basin and sub-basin circulation. These simulations are initialized from and nested in either the Mediterranean Forecasting System (MFS, 1/16º) or Mercator-Océan simulations (MERCATOR, 1/12º). A repeated glider section in the Ibiza Channel, operated by SOCIB, has revealed significant differences between two WMOP simulations using either MFS or MERCATOR (hereafter WMOP-MFS and WMOP-MERC). In this study, MFS, MERCATOR, WMOP-MFS and WMOP-MERC are compared and evaluated using available multi-platform observations such as satellite products (Sea Level Anomaly, Sea Surface Temperature) and in situ measurements (temperature and salinity profiles from Argo floats, CTD, XBT, fixed moorings and gliders; velocity fields from HF radar and currentmeters). A quantitative comparison is necessary to evaluate the capacity of the simulations to reproduce observed ocean features, and to quantify the possible simulations biases. This will in turn allow to improve the simulations, so as to produce better ocean forecast systems, to study and better understand ocean processes and to address climate studies. Therefore, various statistical diagnostics have been developed to assess and intercompare the simulations at various spatial and temporal scales, in different sub-regions (Alboran Sea, Western and Eastern Algerian sub-basins, Balearic Sea, Gulf of Lion), in different dynamical zones (coastal areas, shelves and "open" sea), along key sections (Ibiza and

  14. Molecular systematics of the wolf spider genus Lycosa (Araneae: Lycosidae) in the Western Mediterranean Basin.

    PubMed

    Planas, Enric; Fernández-Montraveta, Carmen; Ribera, Carles

    2013-05-01

    In this study, we present the first molecular phylogeny of the wolf spider genus Lycosa Latreille, 1804 in the Western Mediterranean Basin. With a wide geographic sampling comprising 90 localities and including more than 180 individuals, we conducted species delimitation analyses with a Maximum Likelihood approach that uses a mixed Yule-coalescent model to detect species boundaries. We estimated molecular phylogenetic relationships employing Maximum Likelihood and Bayesian Inference methods using mitochondrial and nuclear sequences. We conducted divergence time analyses using a relaxed clock model implemented in BEAST. Our results recovered 12 species that form four groups: Lycosa tarantula group comprising L. tarantula the type species of the genus, L. hispanica and L. bedeli; Lycosa oculata group composed of L.oculata, L. suboculata and three putative new species; Lycosa baulnyi group formed by the maghrebian L. baulnyi and L. vachoni and Lycosa fasciiventris group that includes two widespread species, L. fasciiventris and L. munieri. We found that each group of species shows a characteristic burrowing behavior and molecular and morphological diagnostic characters. Molecular clock analyses support the hypothesis of a relatively recent evolutionary origin of diversification of the group (4.96 Mya (3.53-6.45 Mya)). The establishment of the Mediterranean-like climate and the Pleistocenic glacial cycles seem to have been the main factors that promoted the diversification within the group. Finally, the results obtained in this study together with the revision of museum specimens, descriptions, redescriptions and illustrations, lead us to propose 18 nomenclatural changes (synonymies, generic transfers and nomina dubia) concerning the genera Lycosa, Allocosa and Hogna in the Western Mediterranean. PMID:23416758

  15. Molecular systematics of the wolf spider genus Lycosa (Araneae: Lycosidae) in the Western Mediterranean Basin.

    PubMed

    Planas, Enric; Fernández-Montraveta, Carmen; Ribera, Carles

    2013-05-01

    In this study, we present the first molecular phylogeny of the wolf spider genus Lycosa Latreille, 1804 in the Western Mediterranean Basin. With a wide geographic sampling comprising 90 localities and including more than 180 individuals, we conducted species delimitation analyses with a Maximum Likelihood approach that uses a mixed Yule-coalescent model to detect species boundaries. We estimated molecular phylogenetic relationships employing Maximum Likelihood and Bayesian Inference methods using mitochondrial and nuclear sequences. We conducted divergence time analyses using a relaxed clock model implemented in BEAST. Our results recovered 12 species that form four groups: Lycosa tarantula group comprising L. tarantula the type species of the genus, L. hispanica and L. bedeli; Lycosa oculata group composed of L.oculata, L. suboculata and three putative new species; Lycosa baulnyi group formed by the maghrebian L. baulnyi and L. vachoni and Lycosa fasciiventris group that includes two widespread species, L. fasciiventris and L. munieri. We found that each group of species shows a characteristic burrowing behavior and molecular and morphological diagnostic characters. Molecular clock analyses support the hypothesis of a relatively recent evolutionary origin of diversification of the group (4.96 Mya (3.53-6.45 Mya)). The establishment of the Mediterranean-like climate and the Pleistocenic glacial cycles seem to have been the main factors that promoted the diversification within the group. Finally, the results obtained in this study together with the revision of museum specimens, descriptions, redescriptions and illustrations, lead us to propose 18 nomenclatural changes (synonymies, generic transfers and nomina dubia) concerning the genera Lycosa, Allocosa and Hogna in the Western Mediterranean.

  16. Crust and upper mantle of the western Mediterranean - Constraints from full-waveform inversion

    NASA Astrophysics Data System (ADS)

    Fichtner, Andreas; Villaseñor, Antonio

    2015-10-01

    We present a full-waveform tomographic model of the western Mediterranean crust and mantle constructed from complete three-component recordings from permanent and temporary networks. The incorporation of body and multi-mode surface waves in the period range from 12-150 s allows us to jointly resolve crustal and mantle structures, including the Guadalquivir, Tajo and Ebro basins at shallow depth, as well as the western Mediterranean subduction system in the transition zone. No mantle plumes can be detected beneath the European Cenozoic rift system, including the Massif Central. In addition to the well-studied Alboran slab, a strong E-W trending high-velocity anomaly is present around 200-300 km depth beneath the Algerian coast. This previously undetected African slab is detached from the surface and broken into two segments. It may be interpreted as the slab that caused the opening of the Liguro-Provençal basin through successive roll-back between 35-15 Ma.

  17. Cenomanian-Turonian organic facies in the western Mediterranean and along the adjacent Atlantic margin

    SciTech Connect

    Kuhnt, W.; Herbin, J.P.; Thurow, J.; Wiedmann, J.

    1988-08-01

    Pre-Cenomanian sediments of the western Mediterranean and adjacent Atlantic margin are characterized by low total organic content (TOC) with an important terrestrial component. During the Cenomanian, TOC increased and the marine component became dominant, culminating around the Cenomanian-Turonian boundary with TOC up to 40%. After the Turonian, organic-rich sediments progressively disappeared and were replaced by more oxygenated sediments. Study methods include considering data from outcrops, DSDP/ODP sites, or petroleum wells. Detailed data from onshore locations allowed the development of high-resolution stratigraphy, analysis of depositional environment, and calculation of sedimentation rates. Analysis of these data indicates Cenoamnian-Turonian organic-rich sediments can be observed in a wide range of bathymetric settings. They are widespread in the western Mediterranean and Atlantic and have been especially studied in Italy (Apennines, southern Alps), Tunisia (Bahloul), Algeria, Morocco (Rif Mountains, Atlas Mountains, Tarfaya), Gibraltar arch, Spain (Betics, Bay of Biscay, Galicia margin), Senegal (Cape Verde basin, Casamance), and Nigeria (Benue, Calabar flank).

  18. A long term (1999-2008) study of radar anomalous propagation conditions in the Western Mediterranean

    NASA Astrophysics Data System (ADS)

    Magaldi, A. V.; Mateu, M.; Bech, J.; Lorente, J.

    2016-03-01

    In this paper a study of the radio propagation environment of electromagnetic waves prevailing in the lower troposphere of the Western Mediterranean basin is presented. Deviations from atmospheric average or standard radio propagation conditions (anomalous propagation or AP) can affect significantly the quality of weather radar observations and other telecommunication systems. This is particularly important when ducting or superrefraction is present and spurious echoes resulting from the interaction of the beam with the ground or sea surface may appear. These AP conditions occur mainly when temperature inversions or strong moisture gradients are present. The period covered in this study ranges from 1999 to 2008 and conditions were derived from the Weather Research and Forecasting (WRF) modeling system, using the Japanese 25-year Reanalysis (JRA25) dataset as initial and boundary data. From the WRF model, we use the temperature, moisture, and pressure fields with a grid length of 30-km horizontal resolution and 250 m vertical resolution to compute several indices such as the Vertical Refractivity Gradient, Vertical Modified Refractivity Gradient and a Ducting Index. Results obtained show that on the Western Mediterranean coast the most favorable conditions for superrefraction are found in summer, while the most affected areas are the Gulf of Valencia, the Strait of Gibraltar and the Northern Gulf of Lion. Additionally, a comparison with radiosonde data recorded in Barcelona (NE Spain) is also performed indicating an overall agreement between model and observational data despite a tendency to decrease subrefractive events by the WRF model.

  19. An evaluation of surface micro- and mesoplastic pollution in pelagic ecosystems of the Western Mediterranean Sea.

    PubMed

    Faure, Florian; Saini, Camille; Potter, Gaël; Galgani, François; de Alencastro, Luiz Felippe; Hagmann, Pascal

    2015-08-01

    This study examines the distribution, abundance and characteristics of surface micro- and mesoplastic debris in the Western Mediterranean Sea. 41 samples were collected in 2011 (summer) and 2012 (summer). Results, firstly, revealed that micro- (<5 mm) and mesoplastic debris were widely and uniformly distributed in this area with average concentrations of 130,000 parts/km(2) and 5700 parts/km(2), respectively. Importantly, a strong correlation between micro- and mesoplastic concentrations was identified. Secondly, a classification based on the shape and appearance of microplastics indicated the predominant presence of fragments (73%) followed by thin films (14%). Thirdly, the average mass ratio of microplastic to dry organic matter has been measured at 0.5, revealing a significant presence of microplastics in comparison to plankton. Finally, a correction method was applied in order to correct wind mixing effect on microplastics' vertical distribution. This data allows for a comprehensive view, for the first time, of the spatial distribution and nature of plastic debris in the Western Mediterranean Sea.

  20. The Pre-Messinian Total Petroleum System of the Provence Basin, Western Mediterranean Sea

    USGS Publications Warehouse

    Pawlewicz, Mark

    2004-01-01

    The Provence Basin is in that portion of the western Mediterranean Sea that is deeper than 2 kilometers. The basin lies essentially beyond the outer continental shelf, between the countries of France, Italy, and Algeria, the Balearic Islands, and the islands of Sardinia and Corsica. It encompasses nearly 300,000 square kilometers and includes the Rhone River submarine fan on the continental slope of southern France. It is province 4068 in the World Energy study. A single, hypothetical, total petroleum system (TPS), the Pre-Messinian TPS (406801), was described for the Provence Basin. The designation hypothetical is used because there is no hydrocarbon production from the basin. The Provence Basin is a deep-water Tertiary rift basin in which the geothermal gradients vary regionally. The Red Sea Basin shares a similar geologic and thermal history with the rifted western Mediterranean Sea and was used as an analog to better understand the genesis of the Provence Basin and as a guide to estimating possible undiscovered amounts of hydrocarbons. For this assessment the basin was given a potential, at the mean, for undiscovered resources of 51 trillion cubic feet (1.4 trillion cubic meters) gas, 0.42 billion barrels oil, and 2.23 million barrels natural gas liquids.

  1. Rapid Middle Eocene temperature change in western North America

    NASA Astrophysics Data System (ADS)

    Methner, Katharina; Mulch, Andreas; Fiebig, Jens; Wacker, Ulrike; Gerdes, Axel; Graham, Stephan A.; Chamberlain, C. Page

    2016-09-01

    Eocene hyperthermals are among the most enigmatic phenomena of Cenozoic climate dynamics. These hyperthermals represent temperature extremes superimposed on an already warm Eocene climate and dramatically affected the marine and terrestrial biosphere, yet our knowledge of temperature and rainfall in continental interiors is still rather limited. We present stable isotope (δ18O) and clumped isotope temperature (Δ47) records from a middle Eocene (41 to 40 Ma) high-elevation mammal fossil locality in the North American continental interior (Montana, USA). Δ47 paleotemperatures of soil carbonates delineate a rapid +9/-11 °C temperature excursion in the paleosol record. Δ47 temperatures progressively increase from 23 °C ± 3 °C to peak temperatures of 32 °C ± 3 °C and subsequently drop by 11 °C. This hyperthermal event in the middle Eocene is accompanied by low δ18O values and reduced pedogenic carbonate concentrations in paleosols. Based on laser ablation U/Pb geochronology of paleosol carbonates in combination with magnetostratigraphy, biostratigraphy, stable isotope, and Δ47 evidence, we suggest that this pronounced warming event reflects the Middle Eocene Climatic Optimum (MECO) in western North America. The terrestrial expression of northern hemisphere MECO in western North America appears to be characterized by warmer and wetter (sub-humid) conditions, compared to the post-MECO phase. Large and rapid shifts in δ18O values of precipitation and pedogenic CaCO3 contents parallel temperature changes, indicating the profound impact of the MECO on atmospheric circulation and rainfall patterns in the western North American continental interior during this transient warming event.

  2. Optical characteristics of biomass burning and desert dust over the Western Mediterranean during summer: a case study

    NASA Astrophysics Data System (ADS)

    Basart, Sara; Sicart, Michaël; María Baldasano, José; Lane, Diego; Comerón, Adolfo

    2013-04-01

    The present contribution reports on the aerosol vertical distributions in Barcelona (Spain) which were obtained when very high aerosol concentrations were observed on summer 2012. An EARLINET lidar system and AERONET sunphotometer located in Barcelona performed intensive measurements in the framework of the ACTRIS (Aerosols, Clouds, and Trace gases Research InfraStructure Network) project. The data that were collected allow the characterization of the optical properties of the aerosols in this region, benefiting from the synergy of various remote sensing instruments. Due to its location in the Mediterranean basin, Barcelona metropolitan area is influenced by two major aerosol source regions: Europe and the Western Mediterranean Basin, as a major source of anthropogenic pollutants, and North Africa, as a principal source of natural dust. As a result, the composition of atmospheric aerosols in Barcelona station is a mixing of aerosols. During the period between 1 - 2 July, AOD reached high values (~ 0.5). In addition to anthropogenic local contributions, other aerosols long-range transported were also detected. Between 1 - 3 July, strong forest fires occurred in Alicante where advected to Barcelona area. On the other hand, between 28th June and 1st July, the northeastern Iberian Peninsula was affected by the intrusion of Saharan dust. The presence of Saharan dust was successfully forecasted by the BSC-DREAM8b dust regional model. MODIS and AERONET data, as well as air-mass backward trajectories confirmed the existence of biomass burning and desert dust in the case examined. Desert dust was detected between 2 and 4 km (above sea level, a.s.l) with maximum dust concentrations at ~ 4 km a.s.l on 1st June. On the other hand, favourable meteorological conditions made possible that biomass burning from Alicante was southern advected to Barcelona during the study period.

  3. First External Quality Assessment of Molecular and Serological Detection of Rift Valley Fever in the Western Mediterranean Region

    PubMed Central

    Monaco, Federica; Cosseddu, Gian Mario; Doumbia, Baba; Madani, Hafsa; El Mellouli, Fatiha; Jiménez-Clavero, Miguel Angel; Sghaier, Soufien; Marianneau, Philippe; Cetre-Sossah, Catherine; Polci, Andrea; Lacote, Sandra; Lakhdar, Magtouf; Fernandez-Pinero, Jovita; Sari Nassim, Chabane; Pinoni, Chiara; Capobianco Dondona, Andrea; Gallardo, Carmina; Bouzid, Taoufiq; Conte, Annamaria; Bortone, Grazia; Savini, Giovanni; Petrini, Antonio; Puech, Lilian

    2015-01-01

    Rift Valley fever (RVF) is a mosquito-borne viral zoonosis which affects humans and a wide range of domestic and wild ruminants. The large spread of RVF in Africa and its potential to emerge beyond its geographic range requires the development of surveillance strategies to promptly detect the disease outbreaks in order to implement efficient control measures, which could prevent the widespread of the virus to humans. The Animal Health Mediterranean Network (REMESA) linking some Northern African countries as Algeria, Egypt, Libya, Mauritania, Morocco, Tunisia with Southern European ones as France, Italy, Portugal and Spain aims at improving the animal health in the Western Mediterranean Region since 2009. In this context, a first assessment of the diagnostic capacities of the laboratories involved in the RVF surveillance was performed. The first proficiency testing (external quality assessment—EQA) for the detection of the viral genome and antibodies of RVF virus (RVFV) was carried out from October 2013 to February 2014. Ten laboratories participated from 6 different countries (4 from North Africa and 2 from Europe). Six laboratories participated in the ring trial for both viral RNA and antibodies detection methods, while four laboratories participated exclusively in the antibodies detection ring trial. For the EQA targeting the viral RNA detection methods 5 out of 6 laboratories reported 100% of correct results. One laboratory misidentified 2 positive samples as negative and 3 positive samples as doubtful indicating a need for corrective actions. For the EQA targeting IgG and IgM antibodies methods 9 out of the 10 laboratories reported 100% of correct results, whilst one laboratory reported all correct results except one false-positive. These two ring trials provide evidence that most of the participating laboratories are capable to detect RVF antibodies and viral RNA thus recognizing RVF infection in affected ruminants with the diagnostic methods currently

  4. First External Quality Assessment of Molecular and Serological Detection of Rift Valley Fever in the Western Mediterranean Region.

    PubMed

    Monaco, Federica; Cosseddu, Gian Mario; Doumbia, Baba; Madani, Hafsa; El Mellouli, Fatiha; Jiménez-Clavero, Miguel Angel; Sghaier, Soufien; Marianneau, Philippe; Cetre-Sossah, Catherine; Polci, Andrea; Lacote, Sandra; Lakhdar, Magtouf; Fernandez-Pinero, Jovita; Sari Nassim, Chabane; Pinoni, Chiara; Capobianco Dondona, Andrea; Gallardo, Carmina; Bouzid, Taoufiq; Conte, Annamaria; Bortone, Grazia; Savini, Giovanni; Petrini, Antonio; Puech, Lilian

    2015-01-01

    Rift Valley fever (RVF) is a mosquito-borne viral zoonosis which affects humans and a wide range of domestic and wild ruminants. The large spread of RVF in Africa and its potential to emerge beyond its geographic range requires the development of surveillance strategies to promptly detect the disease outbreaks in order to implement efficient control measures, which could prevent the widespread of the virus to humans. The Animal Health Mediterranean Network (REMESA) linking some Northern African countries as Algeria, Egypt, Libya, Mauritania, Morocco, Tunisia with Southern European ones as France, Italy, Portugal and Spain aims at improving the animal health in the Western Mediterranean Region since 2009. In this context, a first assessment of the diagnostic capacities of the laboratories involved in the RVF surveillance was performed. The first proficiency testing (external quality assessment--EQA) for the detection of the viral genome and antibodies of RVF virus (RVFV) was carried out from October 2013 to February 2014. Ten laboratories participated from 6 different countries (4 from North Africa and 2 from Europe). Six laboratories participated in the ring trial for both viral RNA and antibodies detection methods, while four laboratories participated exclusively in the antibodies detection ring trial. For the EQA targeting the viral RNA detection methods 5 out of 6 laboratories reported 100% of correct results. One laboratory misidentified 2 positive samples as negative and 3 positive samples as doubtful indicating a need for corrective actions. For the EQA targeting IgG and IgM antibodies methods 9 out of the 10 laboratories reported 100% of correct results, whilst one laboratory reported all correct results except one false-positive. These two ring trials provide evidence that most of the participating laboratories are capable to detect RVF antibodies and viral RNA thus recognizing RVF infection in affected ruminants with the diagnostic methods currently

  5. IBAMar 2.0: 36 years sampling on the Western Mediterranean Sea

    NASA Astrophysics Data System (ADS)

    Aparicio, A.; López-Jurado, J. L.; Balbín, R.; Jansá, J.; Amengual, B.

    2012-04-01

    IBAMar 2.0 is a new database created from the oceanographic data obtained during the development of different oceanographic projects by the Balearic Center of Spanish Institute of Oceanography (IEO) and conducted from 1974 and ongoing in the Western Mediterranean basin (Balearic Sea and Algerian Basin). This database collects data from 27 research projects with 134 oceanographic surveys and 6463 sampling stations. IBAMar 2.0 database covers 36 year sampling and approximately 210,846 km2 in the Western Mediterranean Sea (WM). The effort applied for obtaining this data was growing from less than 100 station/year to more than 700 in the year 2009. IBAMar 2.0 database includes main hydrographic parameters such as pressure, temperature, salinity and others as dissolved oxygen, turbidity, chlorophyll-a and nutrients (nitrates, nitrites, phosphates and silicates). Most of the data from 1990 until now were obtained with multiparametric CTDs, although earlier data corresponding to cast sampling with Niskin bottles were incorporated too. The main goal of this database is to establish a climatology for the most significant variables to study the existence of decadal cycles or long-term trends, trying to better understand the behaviour of the hydrographic conditions of the Spanish Mediterranean coast, at both seasonal and interannual time scale and long term. From these studies is possible to provide answers on topical issues as the thermohaline anomaly of the deep waters of WM, the spatial distribution of dissolved oxygen minimum, or the effects of the Climate Change on the hydrodynamics characteristics of the study area [1]. Future work includes data quality control based on standard protocols like [2] and publishing IBAMar 2.0 (including next surveys) on the website of the Mediterranean Group on Climate Change of IEO (http://www.ma.ieo.es/gcc/). There, the data could be obtained summarized as seasonal climatology. These will include horizontal sections at standard depths

  6. Assessing surface sediment dynamics along the north-west coast of Marsa Dhouiba (Tunisia, southern Mediterranean)

    NASA Astrophysics Data System (ADS)

    Khiari, Nouha; Atoui, Abdelfattah; Brahim, Mouldi; Sammari, Chérif; Charef, Abdelkrim; Aleya, Lotfi

    2016-04-01

    An investigation was conducted from summer 2012 to winter 2013 at 25 stations along the Tunisian coast near Kef Abbed at Marsa Dhouiba (north-east Mediterranean Sea) to analyse grain size, sediment mineralogy and currents. Particle-size analysis shows that sand deposits at shallow depths are characterised by S-shaped curves, indicating a degree of agitation and possible transport by rip currents near the bottom. At greater depths (between 10 and 30 m), the bottom is covered by coarse sand and gravel. A current was observed transporting sediment eastward along the coast; another seaward current was also noted. Generated by wind, swell and especially waves from west to north-west, the two currents transport clay and silt-sized sediment seaward. An Acoustic Doppler Current Profiler showed Marsa Dhouiba's coastal current to follow a direction 175° East, with its main axis running north/north-west parallel to the coast and its minor axis also running north/north-west. Analysis of current components indicates that the velocities u and v are oriented north to south. Sediment evolution in shallow waters is dependent on detrital inputs from streams and winds. The coarse fraction of surface sediments in Marsa Dhouiba presents 87% of total sediments and is located at depths of 10-30 m. Sediment dynamics in the Marsa Dhouiba region are closely related to the west/north-west swell.

  7. Plants used in artisanal fisheries on the Western Mediterranean coasts of Italy

    PubMed Central

    2013-01-01

    Background Artisanal fisheries in the Mediterranean, especially in Italy, have been poorly investigated. There is a long history of fishing in this region, and it remains an important economic activity in many localities. Our research entails both a comprehensive review of the relevant literature and 58 field interviews with practitioners on plants used in fishing activities along the Western Mediterranean Italian coastal regions. The aims were to record traditional knowledge on plants used in fishery in these regions and to define selection criteria for plant species used in artisanal fisheries, considering ecology and intrinsic properties of plants, and to discuss the pattern of diffusion of shared uses in these areas. Methods Information was gathered both from a general review of ethnobotanical literature and from original data. A total of 58 semi-structured interviews were carried out in Liguria, Latium, Campania and Sicily (Italy). Information on plant uses related to fisheries were collected and analyzed through a chi-square residual analysis and the correspondence analysis in relation to habitat, life form and chorology. Results A total of 60 plants were discussed as being utilized in the fisheries of the Western Italian Mediterranean coastal regions, with 141 different uses mentioned. Of these 141 different uses, 32 are shared among different localities. A multivariate statistical analysis was performed on the entire dataset, resulting in details about specific selection criteria for the different usage categories (plants have different uses that can be classified into 11 main categories). In some uses, species are selected for their features (e.g., woody), or habitat (e.g., riverine), etc. The majority of uses were found to be obsolete (42%) and interviews show that traditional fishery knowledge is in decline. There are several reasons for this, such as climatic change, costs, reduction of fish stocks, etc. Conclusions Our research correlates functional

  8. RAMS-forecasts comparison of typical summer atmospheric conditions over the Western Mediterranean coast

    NASA Astrophysics Data System (ADS)

    Gómez, I.; Caselles, V.; Estrela, M. J.; Niclòs, R.

    2014-08-01

    The Regional Atmospheric Modeling System (RAMS) has been used in order to perform a high-resolution numerical simulation of two meteorological events related to the most common atmospheric environments during the summer over the Western Mediterranean coast: mesoscale circulations and western synoptic advections. In this regard, we take advantage of the operational RAMS configuration running within the real-time forecasting system environment already implemented over this Mediterranean area, precisely in the Valencia Region and nearby areas. The attention of this paper is especially focused on identifying the main features of both events and the ability of the model in resolving the associated characteristics as well as in performing a comprehensive evaluation of the model by means of diverse meteorological observations available within the selected periods over the area of study. Additionally, as this paper is centred in RAMS-based forecasts, two simulations are operated applying the most two recent versions of the RAMS model implemented in the above-mentioned system: RAMS 4.4 and RAMS 6.0. Therefore, a comparison among both versions of the model has been performed as well. Finally, it is our intention to contrast the RAMS forecasts for two completely different atmospheric conditions common with the area of study in the summer. A main difference between the simulation of both meteorological situations has been found in the humidity. In this sense, whilst the model underestimates this magnitude considering the mesoscale event, especially at night time, the model reproduces the daily humidity properly under the western synoptic advection.

  9. Mesozoic evolution of the Valencia trough: Implications for the understanding of the Western Mediterranean

    NASA Astrophysics Data System (ADS)

    Etheve, Nathalie; Frizon de Lamotte, Dominique; Mohn, Geoffroy; Roca, Eduard; Gorini, Christian; Blanpied, Christian

    2014-05-01

    The Western Mediterranean records a multi-stage tectonic evolution characterized by a complex succession of rifting to compressive episodes during the Cenozoic. The Valencia through was formed in this geodynamic framework and is classically interpreted as an aborted Tertiary rift related to back-arc extension. Notably, the Tertiary rifting is superimposed to the Jurassic opening of the Tethys basin, the early Cretaceous opening of the Bay of Biscay-Pyrenees basins and the late Cretaceous-early Tertiary inversion of these basins (e.g. Iberian range, Catalan Coastal range). Since the last twenty years, many studies contributed to the understanding of the Tertiary history of this area, whereas the pre-Tertiary evolution of the Valencia trough remains poorly investigated. Therefore, we initiated a research project in the Valencia trough benefiting from the acquisition of high quality seismic surveys allowing a better imaging of the Mesozoic sequences. This PhD project aims to understand the mechanisms and the role of structural inheritance that controlled the evolution of the Valencia trough and its impact on the sedimentary infilling since the Mesozoic. The relation between the sedimentary infilling, subsidence and crustal thinning mechanisms during the Cenozoic are investigated aiming to unravel critical information on rifting processes. This study will be based on correlations between onshore and offshore observations. Structural and stratigraphic evolution will be defined on land and compared with seismic sections and well data at sea. Eventually, these data will enable us to propose coherent land-sea interpretations of the area, providing a better understanding of the tectono-stratigraphic context. Our poster show preliminary results obtained from fieldwork on the western margin of the Valencia trough coupled with seismic interpretations. Eventually, results of this study may lead to better constrain the kinematic reconstruction of the western Mediterranean

  10. North-South precipitation patterns in western North America on interannual-to-decadal timescales

    USGS Publications Warehouse

    Dettinger, M.D.; Cayan, D.R.; Diaz, Henry F.; Meko, D.M.

    1998-01-01

    The overall amount of precipitation deposited along the West Coast and western cordillera of North America from 25??to 55??N varies from year to year, and superimposed on this domain-average variability are varying north-south contrasts on timescales from at least interannual to interdecadal. In order to better understand the north-south precipitation contrasts, their interannual and decadal variations are studied in terms of how much they affect overall precipitation amounts and how they are related to large-scale climatic patterns. Spatial empirical orthogonal functions (EOFs) and spatial moments (domain average, central latitude, and latitudinal spread) of zonally averaged precipitation anomalies along the westernmost parts of North America are analyzed, and each is correlated with global sea level pressure (SLP) and sea surface temperature series, on interannual (defined here as 3-7 yr) and decadal (>7 yr) timescales. The interannual band considered here corresponds to timescales that are particularly strong in tropical climate variations and thus is expected to contain much precipitation variability that is related to El Nino-Southern Oscillation; the decadal scale is defined so as to capture the whole range of long-term climatic variations affecting western North America. Zonal EOFs of the interannual and decadal filtered versions of the zonal-precipitation series are remarkably similar. At both timescales, two leading EOFs describe 1) a north-south seesaw of precipitation pivoting near 40??N and 2) variations in precipitation near 40??N, respectively. The amount of overall precipitation variability is only about 10% of the mean and is largely determined by precipitation variations around 40??-45??N and most consistently influenced by nearby circulation patterns; in this sense, domain-average precipitation is closely related to the second EOF. The central latitude and latitudinal spread of precipitation distributions are strongly influenced by precipitation

  11. Some physical drivers of changes in the winter storm tracks over the North Atlantic and Mediterranean during the Holocene.

    PubMed

    Brayshaw, David James; Hoskins, Brian; Black, Emily

    2010-11-28

    The winter climate of Europe and the Mediterranean is dominated by the weather systems of the mid-latitude storm tracks. The behaviour of the storm tracks is highly variable, particularly in the eastern North Atlantic, and has a profound impact on the hydroclimate of the Mediterranean region. A deeper understanding of the storm tracks and the factors that drive them is therefore crucial for interpreting past changes in Mediterranean climate and the civilizations it has supported over the last 12 000 years (broadly the Holocene period). This paper presents a discussion of how changes in climate forcing (e.g. orbital variations, greenhouse gases, ice sheet cover) may have impacted on the 'basic ingredients' controlling the mid-latitude storm tracks over the North Atlantic and the Mediterranean on intermillennial time scales. Idealized simulations using the HadAM3 atmospheric general circulation model (GCM) are used to explore the basic processes, while a series of timeslice simulations from a similar atmospheric GCM coupled to a thermodynamic slab ocean (HadSM3) are examined to identify the impact these drivers have on the storm track during the Holocene. The results suggest that the North Atlantic storm track has moved northward and strengthened with time since the Early to Mid-Holocene. In contrast, the Mediterranean storm track may have weakened over the same period. It is, however, emphasized that much remains still to be understood about the evolution of the North Atlantic and Mediterranean storm tracks during the Holocene period.

  12. Metabolism of Centropages species in the Mediterranean Sea and the North Atlantic Ocean

    NASA Astrophysics Data System (ADS)

    Gaudy, Raymond; Thibault-Botha, Delphine

    2007-02-01

    Information on the metabolism rates of Centropages typicus and congeneric species ( C. hamatus, C. furcatus, C. brachiatus and C. abdominalis) in neritic areas of the Mediterranean Sea, the North Atlantic Ocean and the Pacific Ocean are reported here. Respiration rates and excretion rates are strongly influenced by abiotic (i.e. temperature, salinity) and biotic factors (i.e. food availability and composition). Differences in the response of respiratory rates to temperature of acclimated, acclimatized and adapted individuals are clearly observed among regions of the Mediterranean Sea and the West and East shores of the Atlantic Ocean. Food supply also strongly affects respiration and excretion rates, as well as the size, sex and stage development of the individuals. The co-measurement of these two rates allows confirmation of the omnivory or carnivory oriented feeding habits of these species. The role of this neritic genus in coastal environment is also discussed.

  13. Understanding the North Atlantic Oscillation and Its Effects in the Mediterranean

    NASA Astrophysics Data System (ADS)

    Trigo, Ricardo M.; Serrano, Sergio M. Vicente

    2010-11-01

    ESF-MedCLIVAR Workshop on Hydrological, Socioeconomic and Ecological Impacts of the North Atlantic Oscillation in the Mediterranean; Zaragoza, Spain, 24-27 May 2010; According to the latest Intergovernmental Panel on Climate Change report, the Mediterranean basin represents one of the most important hot spots of climate change in the world, with recent trends toward a hotter and drier climate being related to changes in atmospheric circulation patterns. Among these patterns the North Atlantic Oscillation (NAO) is the most important one and the only one that exerts a clear influence throughout the year, although with stronger intensity and extension during winter. In the framework of the European Science Foundation's Mediterranean Climate Variability and Predictability (MedCLIVAR) program (http://www.medclivar.eu/), a thematic workshop devoted to the hydrological, socioeconomic, and ecological impacts of the NAO in the Mediterranean area was held in Spain. The main objective of this 3-day workshop was to foster interaction in this increasingly interdisciplinary topic, in particular, among climatologists, hydrologists, geographers, agronomists, biologists, and other scientists. The workshop was attended by 62 participants from 15 different countries and included a mix of senior scientists and graduate students. The workshop was divided into five sessions focusing on (1) natural hazards, including droughts, severe precipitations, floods, heat waves, and cold spells; (2) vegetation activity and agriculture production; (3) natural ecosystems and environment, including forest dynamics, fisheries, dynamics of animal populations, and air quality; (4) geomorphology, including landslides and debris flows, erosivity mechanisms, and surface erosion processes; and (5) renewable energies production, including hydraulic, eolic, and solar.

  14. Deciphering the Western Mediterranean mantle heterogeneities through a statistical approach of the erupted volcanic rocks.

    NASA Astrophysics Data System (ADS)

    Fernandez, M.; Melchiorre, M.; Verges, J.; Coltorti, M.; Torne, M.; Casciello, E.

    2015-12-01

    The Western Mediterranean (We-Me) is characterized by a complex geodynamic history related to subduction events that can be explained by three different models: A) N-NW dipping slab extending from the Gibraltar arc to the Balearic promontory retreating in S-SE direction; B) NW dipping slab under the Balearic promontory, retreating in SE direction towards the Gibraltar strait C) two opposite-directed subductions separated by a transform fault subparellel to the Pierre Fallot Fault Since Oligocene the geological evolution of this part of the Mediterranean is characterized by widespread volcanic activity, related to subductive (orogenic) or intraplate (anorogenic) settings. We merged two huge orogenic and anorogenic datasets containing over 14,000 chemical analyses and processed them through factor analysis, in order to reduce the large number of geochemical parameters describing each sample (major/trace elements, isotopic ratios) through a smaller number of factors. Binary diagrams obtained combining seven resulting factors allow to distinguish the anorogenic field from the orogenic one. Anorogenic rocks usually fall in a narrow range of variation, while orogenic are characterized by a greater variability and by alignment along different trends. These different trends account for large heterogeneities of the sub lithospheric mantle due to extensive recycling of geochemically different materials through time, supporting the idea that different reservoirs are responsible for the Mediterranean volcanism [1]. The spatio-temporal evolution of the We-Me lamproites allows us to speculate a two-step evolution of the mantle beneath southern Spain. This evolution has been evaluated in light of the three models. We therefore propose that a type C model accounting for the presence of two juxtaposed slabs beneath the We-Me is the most feasible model to describe the geodynamic evolution of this area. [1] Conticelli et al. (2009). Lithos 107, 68-92.

  15. The use of non-linearity techniques (correlation dimension) to analyze western Mediterranean rainfall time series

    NASA Astrophysics Data System (ADS)

    Pérez Lluch, María. Carmen; Pascual-Aguilar, Juan Antonio; Andreu, Vicente

    2010-05-01

    The Mediterranean climate patterns are characterized by the great rain variability between years combined whit recurrent drought periods and highly intense rain events. These last becomes critical in this area because incise, usually, immediately after the summer dry period, when the vegetation cover is less capable to protect the soil against rainfall aggressiveness and the wildfire period is finishing. These circumstances favour the intensification of erosion processes and the incidence of landslides, floods, etc. Within the scope of the Valencia Community (Western Mediterranean Region), rain displays a high variability as a result of the Mediterranean sea influence and certain local factors, which favour that great part of the precipitations, take place at micro-scale level, assuming a random behaviour of precipitations. In order to have a better knowledge on rain dynamics and to detect the possible differences caused by the regionalization, four temporal series (40 years) have been selected pertaining to climate stations (Castellón, Valencia, Sueca and Alicante) located in the coastal zone of the study area (Valencia Community, Spain). They are characterized by three concrete climatic regions, and are analysed under the deterministic chaos perspective. A non-linear technique, correlation dimension, is used to carry out this analysis. This technique allows calculating the necessary variables to explain the rain behaviour and to establish suitable models that assume their complexity. The results suggest a possible chaotic behaviour in the four series analysed, obtaining a great variability in the zones of Sueca and Castellón. Statistically, the comparison of the results with the coefficient of variation shows coincidences in almost all the series considered. The only exception was the station of Sueca, where an inverse relation is obtained. Similarly, from a geographic perspective, the obtained results are related favourably to the particular characteristics of

  16. Reappraisal of the 1887 Ligurian earthquake (western Mediterranean) from macroseismicity, active tectonics and tsunami modelling

    NASA Astrophysics Data System (ADS)

    Larroque, C.; Scotti, O.; Ioualalen, M.; Hassoun, V.; Migeon, S.

    2012-04-01

    Early in the morning, of February 23, 1887 a major damaging earthquake hit the towns along the Italian and French Riviera. The earthquake was followed by a tsunami wave with a maximum runup of 2 m near Imperia. At least 600 hundred people died, mainly due to building collapses. The "Ligurian earthquake" occurred at the junction between the Southern French-Italian Alps and the Ligurian Basin in the western Mediterranean. For such historical event, the epicentre and the equivalent magnitude are difficult to characterize with a high degree of precision, and the tectonic fault responsible for the earthquake is still debated today. The recent MALISAR marine geophysical survey allowed identifying a set of N60-70°E recent scarps at the foot of the northern Ligurian margin, revealing a large system of active faults. The scarps correspond to cumulative reverse faulting, with a minor strike-slip component, consistent with the present-day kinematics of earthquakes. Since we have also identified submarine failures in the time-range of the Ligurian earthquake we addressed the question of the submarine slide-induced tsunami. Nevertheless, the maximum volume involved by these submarine slides was in the range of 0.005 km3. Such a volume appears too small to trigger a tsunami with the observed extent and run-up characteristics. Therefore, we propose that the rupture of fault segments belonging to the 80 km-long northern Ligurian Faults system is the source of the 1887 Ligurian earthquake. We investigate the macroseismic data from the historical databases SISFRANCE-08 and DBMI-04 using several models of intensity attenuation with distance and focal depth. Modelling results are consistent with the location offshore, indicating an epicentre around 43.70°-43.78°N and 7.81°-8.07°E with a magnitude Mw in the range of 6.3-7.5. A refinement of this range of magnitude is discussed in the light of the tsunami modelling. Numerous earthquake sources scenarios have been tested with

  17. Evaluation of Atlantic bluefin tuna reproductive potential in the western Mediterranean Sea

    NASA Astrophysics Data System (ADS)

    Aranda, Guillermo; Medina, Antonio; Santos, Agustín; Abascal, Francisco J.; Galaz, Txema

    2013-02-01

    Ovarian tissue samples of Atlantic bluefin tuna (ABFT) spawners (n = 49) caught by purse seine in the Balearic Sea (western Mediterranean) were used to assess the stock reproductive characteristics. The frequency of spawning females estimated by the postovulatory follicle method was 84% and the spawning periodicity 1.2 days. Using an unbiased stereological method, the realized batch fecundity was estimated from counts of postovulatory follicles (POFs), whereas the batch fecundity of the subsequent spawn was estimated by quantification of the number of follicles containing oocytes at maturation stage (OMFs). The number of POFs was used as a reliable proxy of the realized batch fecundity, as it represents the actual number of eggs released in the last spawning event. The average relative realized batch fecundity was estimated to be approximately 48 eggs g- 1 of total body mass. While the absolute batch fecundity was isometrically related to the fork length, the relative batch fecundity was not dependent on fish size, which leads to the assumption that all length classes contribute proportionally to their size, towards the total number of eggs spawned by the broodstock. Size-related variations in the sex ratio were observed in the study area and in other Mediterranean locations; females were more abundant in mid-size classes while males predominated in large-size classes.

  18. Conservation of native Pacific trout diversity in western North America

    USGS Publications Warehouse

    Penaluna, Brooke E.; Abadía-Cardoso, Alicia; Dunham, Jason; García de León, Francisco J; Gresswell, Robert E.; Luna, Arturo Ruiz; Taylor, Eric B.; Shepard, Bradley B.; Al-Chokhachy, Robert K.; Muhlfeld, Clint C.; Bestgen, Kevin R.; Rogers, Kevin H.; Escalante, Marco A; Keeley, Ernest R; Temple, Gabriel; Williams, Jack E.; Matthews, Kathleen; Pierce, Ron; Mayden, Richard L.; Kovach, Ryan; Garza, John Carlos; Fausch, Kurt D.

    2016-01-01

    Pacific trout Oncorhynchus spp. in western North America are strongly valued in ecological, socioeconomic, and cultural views, and have been the subject of substantial research and conservation efforts. Despite this, the understanding of their evolutionary histories, overall diversity, and challenges to their conservation is incomplete. We review the state of knowledge on these important issues, focusing on Pacific trout in the genus Oncorhynchus. Although most research on salmonid fishes emphasizes Pacific salmon, we focus on Pacific trout because they share a common evolutionary history, and many taxa in western North America have not been formally described, particularly in the southern extent of their ranges. Research in recent decades has led to the revision of many hypotheses concerning the origin and diversification of Pacific trout throughout their range. Although there has been significant success at addressing past threats to Pacific trout, contemporary and future threats represented by nonnative species, land and water use activities, and climate change pose challenges and uncertainties. Ultimately, conservation of Pacific trout depends on how well these issues are understood and addressed, and on solutions that allow these species to coexist with a growing scope of human influences.

  19. Impact of climate variability in the western Mediterranean during the last 20,000 years: oceanic and atmospheric responses

    NASA Astrophysics Data System (ADS)

    Rodrigo-Gámiz, M.; Martínez-Ruiz, F.; Jiménez-Espejo, F. J.; Gallego-Torres, D.; Nieto-Moreno, V.; Romero, O.; Ariztegui, D.

    2011-07-01

    Eolian input fluctuations and paleoceanographic conditions in the western Mediterranean have been reconstructed by using a multi-proxy approach to infer climate variability for the last 20,000 yr. A sediment core from the East Alboran Sea basin provides high-resolution geochemical, mineralogical and grain size distribution records from the Last Glacial Maximum onward. The accurate chronology obtained, closely related with the North Greenland Ice core Project, has provided a detailed paleoclimate reconstruction at the centennial-millennial time scale. Mineral and chemical compositions as well as sediment grain size distribution have been used to establish both fluvial and eolian input variations, deep-water current intensity, and ventilation and productivity conditions at the time of deposition. During the cold period Greenland Stadial-2a, the analyzed proxies evidence significant climate oscillations. Redox proxies, showing marked Mn/Al and Fe/Al peaks, as well as granulometric parameters, support major changes in thermohaline circulation, with active circulation triggered by the Western Mediterranean Deep Water formation. Ba/Al ratios and the presence of authigenic barite point to high productivity during the Last Heinrich event. At this time, Zr/Al, Si/Al and Ti/Al ratios as well as quartz and palygorskite contents also corroborate dryer conditions in the Alboran borderlands, with a major reorganization of atmospheric circulation at the beginning of the deglaciation and during the Last Heinrich event. In contrast, a decreasing trend in the Zr/Al ratio and increasing Mg/Al, K/Al and illite + chlorite/kaolinite ratios would indicate enhanced river runoff and supporting lower eolian dust input and wetter periods during the Bölling-Alleröd. Short-term and abrupt climate oscillations such as the Intra-Alleröd Cold Period are likewise reflected by minor yet conspicuous changes in eolian proxies. During the Younger Dryas, we distinguish an initial cold and dry phase

  20. Cetacean response to summer maritime traffic in the Western Mediterranean Sea.

    PubMed

    Campana, I; Crosti, R; Angeletti, D; Carosso, L; David, L; Di-Méglio, N; Moulins, A; Rosso, M; Tepsich, P; Arcangeli, A

    2015-08-01

    Maritime traffic is one of many anthropogenic pressures threatening the marine environment. This study was specifically designed to investigate the relationship between vessels presence and cetacean sightings in the high sea areas of the Western Mediterranean Sea region. We recorded and compared the total number of vessels in the presence and absence of cetacean sightings using data gathered during the summer season (2009-2013) along six fixed transects repeatedly surveyed. In locations with cetacean sightings (N = 2667), nautical traffic was significantly lower, by 20%, compared to random locations where no sightings occurred (N = 1226): all cetacean species, except bottlenose dolphin, were generally observed in locations with lower vessel abundance. In different areas the species showed variable results likely influenced by a combination of biological and local environmental factors. The approach of this research helped create, for the first time, a wide vision of the different responses of animals towards a common pressure. PMID:26009840

  1. The Central-Western Mediterranean: Anomalous igneous activity in an anomalous collisional tectonic setting

    NASA Astrophysics Data System (ADS)

    Lustrino, Michele; Duggen, Svend; Rosenberg, Claudio L.

    2011-01-01

    The central-western Mediterranean area is a key region for understanding the complex interaction between igneous activity and tectonics. In this review, the specific geochemical character of several 'subduction-related' Cenozoic igneous provinces are described with a view to identifying the processes responsible for the modifications of their sources. Different petrogenetic models are reviewed in the light of competing geological and geodynamic scenarios proposed in the literature. Plutonic rocks occur almost exclusively in the Eocene-Oligocene Periadriatic Province of the Alps while relatively minor plutonic bodies (mostly Miocene in age) crop out in N Morocco, S Spain and N Algeria. Igneous activity is otherwise confined to lava flows and dykes accompanied by relatively greater volumes of pyroclastic (often ignimbritic) products. Overall, the igneous activity spanned a wide temporal range, from middle Eocene (such as the Periadriatic Province) to the present (as in the Neapolitan of southern Italy). The magmatic products are mostly SiO 2-oversaturated, showing calcalkaline to high-K calcalcaline affinity, except in some areas (as in peninsular Italy) where potassic to ultrapotassic compositions prevail. The ultrapotassic magmas (which include leucitites to leucite-phonolites) are dominantly SiO 2-undersaturated, although rare, SiO 2-saturated (i.e., leucite-free lamproites) appear over much of this region, examples being in the Betics (southeast Spain), the northwest Alps, northeast Corsica (France), Tuscany (northwest Italy), southeast Tyrrhenian Sea (Cornacya Seamount) and possibly in the Tell region (northeast Algeria). Excepted for the Alpine case, subduction-related igneous activity is strictly linked to the formation of the Mediterranean Sea. This Sea, at least in its central and western sectors, is made up of several young (< 30 Ma) V-shaped back-arc basins plus several dispersed continental fragments, originally in crustal continuity with the European

  2. Isolation of 91 polymorphic microsatellite loci in the western Mediterranean endemic Carex helodes (Cyperaceae)1

    PubMed Central

    Arroyo, Juan M.; Escudero, Marcial; Jordano, Pedro

    2016-01-01

    Premise of the study: Microsatellite primers were developed for Carex helodes (Cyperaceae), a western Mediterranean endemic that is locally distributed in southern Portugal and southwestern Spain and rare in northern Morocco. Methods and Results: One hundred nine nuclear microsatellite markers were developed using a shotgun pyrosequencing method, resulting in 91 polymorphic and 18 monomorphic loci when tested using 19 individuals sampled from five populations from Portugal, Spain, and Morocco. Loci averaged 3.23 alleles per locus (SD = 1.15). In a single population (Cortelha population, Portugal), the 34 most polymorphic loci showed a mean observed heterozygosity of 0.357 (SD = 0.292) and mean expected heterozygosity of 0.384 (SD = 0.255). Conclusions: Next-generation sequencing allowed us to develop a high number of genetic markers with levels of polymorphism adequate to study gene flow among populations. However, when genotyping the individuals within a population, we found low levels of variation. PMID:26819859

  3. One decade of thermohaline variability in the deep western Mediterranean Sea (2004-2014)

    NASA Astrophysics Data System (ADS)

    Schroeder, Katrin; Ismail, S. Ben; Bryden, Harry; Borghini, Mireno; Sparnocchia, Stefania; Chiggiato, Jacopo; Ribotti, Alberto

    2015-04-01

    Recent intense deep water formation events in the western Mediterranean have produced a huge amount of a new deep water. Significantly warmer and saltier than previously, it substituted the resident deep water. The deep structure and properties began to change after winter 2004/2005 and the water rapidly spread towards the interior of the basin, in the direction of the Strait of Gibraltar and within the Tyrrhenian Sea. The changes observed over the past 10 years are substantial: since 2004 we witnessed increases in deep water temperature and salinity 3-4 times faster than during 1961-2004. The possible impacts these changes could have on a global scale are still an open issue.

  4. Isotopes in Western North American snowpack 1993 - 2013

    NASA Astrophysics Data System (ADS)

    Anderson, L.; Berkelhammer, M. B.; VanSistine, P.

    2013-12-01

    The interpretation of oxygen isotope-based climate proxies in the western North America, including those from lake sediment calcite, tree cellulose, leaf waxes, and speleothems, each depend on assumptions about the site-specific and regional patterns of the isotopic composition of seasonal precipitation. Here we explore isotopic ratios in the integrated Rocky Mountain snowpack (IRMS) since 1993 for >45 high-elevation locations per year between northern Montana and northern New Mexico. The isotopic network comprises the most extensive spatial and temporal effort to document snowpack isotopic values to be conducted beyond Polar Regions. The dataset provides new insight into the processes that influence the isotopic composition of Western North American winter precipitation. Preliminary assessments indicate a number of spatial features that are similar to those observed in existing isotopic networks from North America but with additional spatial and temporal detail over this topographically complex region. Lower isotopic ratios generally occur with higher latitude, a reflection of condensation at cooler temperatures associated with more common Arctic air mass incursions, which bring isotopically depleted vapor. Higher elevation sites also generally have lower isotopes ratios, but this is most likely as a consequence of orographic rainout. East-west isotopic gradients occur as a consequence of preferential rainout as air masses pass from west to east over the spine of the cordillera and when southern tracking lows generate east to west upslope flow. Previous studies have also indicated that isotopes in precipitation track interannual shifts in atmospheric regimes that lead to changes in jet stream strength and position and the frequency that Arctic, sub-tropical or Pacific air masses reach the Rockies. We hypothesize that these changes also yield distinct impacts on the isotopic ratio of the snowpack and use the unique spatial and temporal density of the IRMS dataset

  5. Spatially Explicit Modeling Reveals Cephalopod Distributions Match Contrasting Trophic Pathways in the Western Mediterranean Sea

    PubMed Central

    Puerta, Patricia; Hunsicker, Mary E.; Quetglas, Antoni; Álvarez-Berastegui, Diego; Esteban, Antonio; González, María; Hidalgo, Manuel

    2015-01-01

    Populations of the same species can experience different responses to the environment throughout their distributional range as a result of spatial and temporal heterogeneity in habitat conditions. This highlights the importance of understanding the processes governing species distribution at local scales. However, research on species distribution often averages environmental covariates across large geographic areas, missing variability in population-environment interactions within geographically distinct regions. We used spatially explicit models to identify interactions between species and environmental, including chlorophyll a (Chla) and sea surface temperature (SST), and trophic (prey density) conditions, along with processes governing the distribution of two cephalopods with contrasting life-histories (octopus and squid) across the western Mediterranean Sea. This approach is relevant for cephalopods, since their population dynamics are especially sensitive to variations in habitat conditions and rarely stable in abundance and location. The regional distributions of the two cephalopod species matched two different trophic pathways present in the western Mediterranean Sea, associated with the Gulf of Lion upwelling and the Ebro river discharges respectively. The effects of the studied environmental and trophic conditions were spatially variant in both species, with usually stronger effects along their distributional boundaries. We identify areas where prey availability limited the abundance of cephalopod populations as well as contrasting effects of temperature in the warmest regions. Despite distributional patterns matching productive areas, a general negative effect of Chla on cephalopod densities suggests that competition pressure is common in the study area. Additionally, results highlight the importance of trophic interactions, beyond other common environmental factors, in shaping the distribution of cephalopod populations. Our study presents a valuable

  6. Dynamics of double-polarity subduction: application to the Western Mediterranean

    NASA Astrophysics Data System (ADS)

    Peral, M.; Zlotnik, S.; Fernandez, M.; Verges, J.; Jiménez-Munt, I.; Torne, M.

    2015-12-01

    The evolution of the Western Mediterranean is a highly debated question by geologists and geophysicists. Even though most scientists agree in considering slab roll-back to be the driving mechanism of the tectonic evolution of this area, there is still no consensus about the initial setup and its time evolution. A recent model proposed by Vergés and Fernàndez (2012) suggests a lateral change in subduction polarity of the Ligurian-Thetys oceanic domain to explain the formation and evolution of the Betic-Rif orogenic system and the associated Alboran back-arc basin. Such geodynamic scenario is also proposed for different converging regions. The aim of this study is to analyze the dynamic evolution of a double-polarity subduction process and its consequences in order to test the physical feasibility of this interaction and provide geometries and evolutions comparable to those proposed for the Western Mediterranean. The 3D numerical model of double-polarity subduction is carried out via the Underworld framework. Tectonic plate behavior is described by equations of fluid dynamics in the presence of several different phases. Underworld solves a non-linear Stokes flow problem using Finite Elements combined with particle-in-cell approach, thus the discretization combines a standard Eulerian Finite Element mesh with Lagrangian particles to track the location of the phases. The final model consists of two oceanic plates with viscoplastic rheology subducting into the upper mantle and the problem is driven by Rayleigh-Taylor instability. The main factors to be studied are the interaction between the two plates, the poloidal and toroidal mantle fluxes, the velocity variations of slabs, the stress distribution and the variations in the trench morphology.

  7. Dynamics of double-polarity subduction: application to the Western Mediterranean

    NASA Astrophysics Data System (ADS)

    Peral, Mireia; Zlotnik, Sergio; Fernandez, Manel; Vergés, Jaume; Jiménez-Munt, Ivone; Torne, Montserrat

    2016-04-01

    The evolution of the Western Mediterranean is a highly debated question by geologists and geophysicists. Even though most scientists agree in considering slab roll-back to be the driving mechanism of the tectonic evolution of this area, there is still no consensus about the initial setup and its time evolution. A recent model suggests a lateral change in subduction polarity of the Ligurian-Thetys oceanic domain to explain the formation and evolution of the Betic-Rif orogenic system and the associated Alboran back-arc basin. Such geodynamic scenario is also proposed for different converging regions. The aim of this study is to analyze the dynamic evolution of a double-polarity subduction process and its consequences in order to test the physical feasibility of this interaction and provide geometries and evolutions comparable to those proposed for the Western Mediterranean. The 3D numerical model is carried out via the Underworld framework. Tectonic plate behavior is described by equations of fluid dynamics in the presence of several different phases. Underworld solves a non-linear Stokes flow problem using Finite Elements combined with particle-in-cell approach, thus the discretization combines a standard Eulerian Finite Element mesh with Lagrangian particles to track the location of the phases. The final model consists of two oceanic plates with viscoplastic rheology subducting into the upper mantle in opposite direction and the problem is driven by Rayleigh-Taylor instability. We study the influence of the boundary conditions in the model evolution, and the slab deformation produced by the proximity between both plates. Moreover the case of asymmetric friction on the lateral sides of slabs is also considered. Simulations of single subduction models are used as a reference, to compare results and understand the influence of the second plate. We observe slight differences in the trench retreat velocity and the slab morphology near the contact area when plates are

  8. Spatially Explicit Modeling Reveals Cephalopod Distributions Match Contrasting Trophic Pathways in the Western Mediterranean Sea.

    PubMed

    Puerta, Patricia; Hunsicker, Mary E; Quetglas, Antoni; Álvarez-Berastegui, Diego; Esteban, Antonio; González, María; Hidalgo, Manuel

    2015-01-01

    Populations of the same species can experience different responses to the environment throughout their distributional range as a result of spatial and temporal heterogeneity in habitat conditions. This highlights the importance of understanding the processes governing species distribution at local scales. However, research on species distribution often averages environmental covariates across large geographic areas, missing variability in population-environment interactions within geographically distinct regions. We used spatially explicit models to identify interactions between species and environmental, including chlorophyll a (Chla) and sea surface temperature (SST), and trophic (prey density) conditions, along with processes governing the distribution of two cephalopods with contrasting life-histories (octopus and squid) across the western Mediterranean Sea. This approach is relevant for cephalopods, since their population dynamics are especially sensitive to variations in habitat conditions and rarely stable in abundance and location. The regional distributions of the two cephalopod species matched two different trophic pathways present in the western Mediterranean Sea, associated with the Gulf of Lion upwelling and the Ebro river discharges respectively. The effects of the studied environmental and trophic conditions were spatially variant in both species, with usually stronger effects along their distributional boundaries. We identify areas where prey availability limited the abundance of cephalopod populations as well as contrasting effects of temperature in the warmest regions. Despite distributional patterns matching productive areas, a general negative effect of Chla on cephalopod densities suggests that competition pressure is common in the study area. Additionally, results highlight the importance of trophic interactions, beyond other common environmental factors, in shaping the distribution of cephalopod populations. Our study presents a valuable

  9. Historical development of ornithophily in the western North American flora.

    PubMed Central

    Grant, V

    1994-01-01

    The 129 ornithophilous plant species in western North America have floristic affinities with one or the other of four geofloras: the Arcto-Tertiary flora (101 species), Madro-Tertiary flora (19 species), Madrean-Tethyan flora (8 species), and Neotropical flora (1 species). The last three floras have been in continuous contact with hummingbirds since some time early in the Tertiary, and ornithophily is old in this subset of western ornithophilous plants. The Arcto-Tertiary flora had no contact with hummingbirds in Eurasia or in its early history in North America. Ornithophily is a new condition in Arcto-Tertiary plant groups, dating from the first significant contact of these plants with hummingbirds in the Eocene. Buildup of the hummingbird pollination system in the Arcto-Tertiary flora is expected to be gradual and stepwise for several reasons. Ornithophilous plant groups with Arcto-Tertiary affinities in the modern western flora form a graded series with respect to taxonomic rank, taxonomic size, and ecological diversity. The series consists of one large genus (Castilleja), three small genera (Zauschneria, etc.), species groups in several genera (Penstemon, Aquilegia, etc.), single ornithophilous species in otherwise nonornithophilous genera (seven genera--e.g., Pedicularis, Monardella), and ornithophilous races in otherwise nonornithophilous species (known in two species). It is suggested that the gradations in size of the groups approximately reflect stages in their development, with the largest ornithophilous genus being oldest, with single ornithophilous species being relatively recent, and with ornithophilous races being most recent. The observed distribution of numbers of ornithophilous species among genera is in agreement with the expectation of a gradual and stepwise development of ornithophily. PMID:7937964

  10. Regional variations in shear wave anisotropy beneath western North America

    NASA Astrophysics Data System (ADS)

    Currie, C.; Cassidy, J.; Hyndman, R.; Bostock, M.

    2003-04-01

    We have examined shear wave splitting of SKS phases at 25 broadband stations in western North America to constrain regional trends in anisotropy at the Cascadia subduction zone (CSZ) and adjacent regions. At most stations, well-constrained shear wave splitting parameters (delay time and fast direction) were obtained for data from a wide range of azimuths. Delay times of 1.0 to 1.5 s indicate a mantle source for the anisotropy, most likely strain-induced lattice preferred orientation of anisotropic mantle minerals. The fast directions at the CSZ are in good agreement with models for mantle deformation associated with subduction. Within the forearc, fast directions at stations above the Juan de Fuca Plate are parallel to the subduction direction (N70E), suggesting deformation in the mantle beneath the plate due to plate motion. Above the Explorer Plate at the northern end of the CSZ, fast directions are N30E. This may reflect either the more northerly subduction direction of that plate, or a transition from subduction-related deformation to along-margin flow parallel to the transcurrent Queen Charlotte Fault to the north. At four stations in the central backarc, fast directions are parallel to the Juan de Fuca-North America convergence direction, consistent with models of subduction-induced mantle wedge flow. No clear splitting was observed at the two most northern backarc stations, indicating little to no horizontal anisotropy beneath these stations, possibly due to vertical mantle flow around the northern edge of the subducted plate. At a station near the western edge of the North America craton, the splitting parameters show significant azimuthal variations with a 90° periodicity, characteristic of multiple layers of anisotropy. The observations were fit using a two-layer model with an upper anisotropic layer with a fast direction of N12E and delay time of 1.4 s, and a lower layer with a fast direction of N81E and delay time of 2.0 s. The North America craton is

  11. PICASSO: Shear velocities in the Western Mediterranean from Rayleigh Wave tomography

    NASA Astrophysics Data System (ADS)

    Palomeras, I.; Thurner, S.; Levander, A.

    2012-12-01

    The Western Mediterranean has been affected by complex subduction and slab rollback, simultaneously with compression due to African-European convergence. The deformed region occupies a wide area from the intra-continental Atlas mountain belt in Morocco to the southern Iberian Massif in Spain. Evolutionary models of the Western Mediterranean invoke extensive slab rollback and compression in the Cenozoic, as well as likely upper mantle delamination scenarios during formation of the Alboran domain, the Betics, Rif, and Atlas Mountains. PICASSO (Program to Investigate Convective Alboran Sea System Overturn) is a multidisciplinary, international investigation of the Alboran System and surrounding areas. In this study we have analyzed data from the 95 PICASSO broadband stations with data from the Spanish IberArray and Siberia Array in Spain and Morocco, the University of Muenster array in the Atlas Mountains and the permanent Spanish and Portuguese networks. We present Rayleigh wave tomography results made from 168 teleseimic events recorded by 237 stations from April 2009 to April 2011. We measured Rayleigh phase velocities using the two-plane-wave method to remove complications due to multi-pathing, and finite-frequency kernels to improve lateral resolution. Phase velocities were then inverted for shear velocity structure on a grid of 0.5 by 0.5 degree to form a well-resolved 3D shear velocity model to 230 km depth. Our results show low S-velocities (2.9 km/s) in the crust beneath the Gibraltar Strait. Low upper mantle S-velocities are mapped beneath the Middle and High Atlas at ~60 km depth suggesting an elevated asthenosphere beneath these young mountain belts, in agreement with receiver functions analysis (Thurner et al, this session). Beneath the Western Alboran Sea, upper-mantle velocities change laterally from high velocities (>4.5 km/s) in the east to lower velocities to the west (~4.3 km/s). The Rayleigh wave tomography is consistent with P-tomography that

  12. Measurements of Land Subsidence Rates on the North-western Portion of the Nile Delta Using Radar Interferometry Techniques

    NASA Astrophysics Data System (ADS)

    Fugate, Joseph M.

    The Nile Delta is home to around 75 million people and most of Egypt's farmland and agricultural production. This area is currently threatened by Mediterranean Sea waters due to factors such as sediment starvation, climate change, and sea level fluctuations as well as subsidence. The low elevation and relief of the Nile Delta exposes many coastal communities, including the city of Alexandria, to potential inundation. This situation has become a concern for the area's residents but a better understanding of the processes occurring there can aid in deciding a suitable response. Recent studies have documented Holocene subsidence rates in the northeast part of the Nile Delta that average up to 8mm/year. In this study, PS-InSAR techniques are used to measure modern land subsidence rates on the north-central and north-western Nile Delta. Persistent Scatterer Interferometric Synthetic Aperture Radar (PS-InSAR) techniques were applied to 23 ESA radar scenes from 2 orbital tracks spanning from 1992 to 2000 in the north-central and north-west portions of the Nile Delta. The area includes the cities of Alexandria, Greater Mahala, and Mansoura as well as the Rosetta promontory and lake Burullus, Idku Lagoon, and Maryut Lagoon. Results indicate that modern average-vertical ground motion velocities for the north-western and north-central Nile Delta range from emergent to subsidence of 8.5 mm/yr. The range of velocities measured are spatially varied in a complex way across the study area. Patterns of subsidence correlate closely to areas of most recent sediment deposition such as along coastlines and rivers, as well as in lagoons and lakes. Average subsidence velocities are also lower across the western sections of the Nile Delta than in the northeastern delta.

  13. Volatile organic compounds (VOCs) in photochemically aged air from the Eastern and Western Mediterranean

    NASA Astrophysics Data System (ADS)

    Derstroff, Bettina; Stoenner, Christof; Klüpfel, Thomas; Sauvage, Carina; Crowley, John; Phillips, Gavin; Parchatka, Uwe; Lelieveld, Jos; Williams, Jonathan

    2015-04-01

    In summer 2014 a comprehensively instrumented measurement campaign (CYPHEX) was conducted in northwest Cyprus in order to investigate atmospheric oxidation chemistry in the Mediterranean region. The site was periodically influenced by the northerly Etesian winds advecting air from Eastern Europe (Turkey and Greece) and from westerly winds bringing more photochemically processed emissions from Western Europe (Spain and France). In this study the data from a Proton Transfer Reaction Time of Flight Mass Spectrometer (PTR-TOF-MS) are analyzed. Generally, oxidized volatile organic compounds (OVOCs) such as methanol and acetone were measured in high mixing ratios (max. 9.5 ppb, min. 1.3 ppb, average 3.2 ppb for methanol, max. 7.9 ppb, min. 1.3 ppb, average 2.4 ppb for acetone ) while precursors like propane showed low values (max. 500 ppt). This demonstrates that the air measured was oxidized to a high degree over the Mediterranean Sea. Low values of acetonitrile throughout the campaign indicated no significant influence of biomass burning on the data. Temporal variations in VOC mixing ratios and precursor/product ratios over the campaign can be explained by using the HYSPLIT backward trajectory model which delineated air masses originating from Eastern and Western Europe. Diel variations of reactive VOCs such as isoprene and terpenes were also observed at the site. A sharp increase in isoprene and monoterpenes at circa 9:00 local time indicated that the 600 m hilltop site was influenced by ascending boundary layer air at this time. In this study, particular emphasis is placed on acetic (ethanoic) acid measured by PTR- TOF-MS and calibrated by a permeation source. Acetic acid is an atmospheric oxidation product of multiple volatile organic compounds, emitted directly from vegetation, and found in abundance in the Mediterranean region (max. 2.7 ppb, min. 0.2 ppb, average 0.8 ppb). Acetic acid contributes to the acidity of precipitation in remote areas, can be incorporated

  14. View north, showing western docking structure U.S. Coast Guard ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    View north, showing western docking structure - U.S. Coast Guard Sandy Hook Station, Western Docking Structure, West of intersection of Canfield Road & Hartshorne Drive, Highlands, Monmouth County, NJ

  15. Contribution of planktonic and benthic food sources to the diet of the reef-forming vermetid gastropod Dendropoma petraeum in the western Mediterranean

    NASA Astrophysics Data System (ADS)

    Vizzini, Salvatrice; Colombo, Francesca; Costa, Valentina; Mazzola, Antonio

    2012-01-01

    In the Mediterranean Sea, the vermetid Dendropoma petraeum (Monterosato, 1884) forms highly biodiverse reefs that have received increasing attention in recent years although very little is known about the food habit of this species. The main goal of this study was to describe the trophic role of planktonic and benthic food sources for D. petraeum. Specimens from three morphological zones of the reef (inner edge, cuvette and outer edge) at two sites with different wave exposure along the north-western coast of Sicily (Italy; western Mediterranean) were compared for δ 13C and δ 15N. Isotopic determinations were also carried out on potential food sources identified in epilithon, reef macroalgae and suspended particulate organic matter. δ 13C for D. petraeum showed significantly more depleted values in the more exposed conditions (i.e. the site with higher wave exposure and outer edge of the reef), while δ 15N did not differ appreciably. These results suggest greater exploitation of benthic sources in the sheltered than in the exposed site and reveal diet shift and trophic flexibility at a small spatial scale for the reef-former D. petraeum.

  16. Compressional tectonic inversion of the Algero-Balearic basin: Latemost Miocene to present oblique convergence at the Palomares margin (Western Mediterranean)

    NASA Astrophysics Data System (ADS)

    Giaconia, Flavio; Booth-Rea, Guillermo; Ranero, César R.; Gràcia, Eulàlia; Bartolome, Rafael; Calahorrano, Alcinoe; Lo Iacono, Claudio; Vendrell, Montserrat G.; Cameselle, Alejandra L.; Costa, Sergio; Gómez de la Peña, Laura; Martínez-Loriente, Sara; Perea, Hector; Viñas, Marina

    2015-07-01

    Interpretation of new multichannel seismic reflection profiles indicates that the Palomares margin was formed by crustal-scale extension and coeval magmatic accretion during middle to late Miocene opening of the Algero-Balearic basin. The margin formed at the transition between thinned continental crust intruded by arc volcanism and back-arc oceanic crust. Deformation produced during the later positive inversion of the margin offshore and onshore is partitioned between ~N50°E striking reverse faults and associated folds like the Sierra Cabrera and Abubacer anticlines and N10-20°E sinistral strike-slip faults like Palomares and Terreros faults. Parametric subbottom profiles and multibeam bathymetry offshore, structural analysis, available GPS geodetic displacement data, and earthquake focal mechanisms jointly indicate that tectonic inversion of the Palomares margin is currently active. The Palomares margin shows a structural pattern comparable to the north Maghrebian margins where Africa-Eurasia plate convergence is accommodated by NE-SW reverse faults, NNW-SSE sinistral faults, and WNW-ESE dextral ones. Contractive structures at this margin contribute to the general inversion of the Western Mediterranean since ~7 Ma, coeval to inversion at the Algerian margin. Shortening at the Alboran ridge and Al-Idrisi faults occurred later, since 5 Ma, indicating a westward propagation of the compressional inversion of the Western Mediterranean.

  17. Deep-sea suprabenthos assemblages (Crustacea) off the Balearic Islands (western Mediterranean): Mesoscale variability in diversity and production

    NASA Astrophysics Data System (ADS)

    Cartes, J. E.; Mamouridis, V.; Fanelli, E.

    2011-04-01

    The composition of suprabenthic crustacean assemblages, their diversity, production (P) and production/biomass (P/B) ratios, were analyzed at species level along two transects situated to the north (N) and south (S) of Mallorca (Balearic Islands, western Mediterranean) at depths between 134 m and 760 m, based on a ca. bi-monthly sampling performed between August 2003 and June 2004. Differences with depth and season in assemblage composition and diversity were analyzed as a function of the contrasting environmental features (e.g. water mass dynamics) of the two areas. We identified 187 species (18 decapods, 5 euphausiids, 16 mysids, 76 gammaridean amphipods, 13 hyperiids, 1 caprellid, 21 isopods and 37 cumaceans). Substantial mesoscale variability in the deep-sea suprabenthic assemblages coupled with diversity trends between the N and S transects were found. Seasonality was the most important gradient influencing the dynamics of suprabenthos over the upper (350 m) and middle (650-750 m) slope in the N area. Conversely, the S area appeared to be more stable temporally with depth as the main gradient inducing assemblage differences. Different depth-related patterns were observed both for diversity and P/B. To the north diversity was very low at the shelf-break, increasing on the upper-slope ( H' > 3.00) and then decreasing again on the middle-slope. To the south diversity increased smoothly downward, reaching the highest values on the middle-slope. Regarding productivity, P/B was highest at intermediate depths to the north (over ca. 450-500 m), while to the south highest P/Bs were found deeper (over ca. 600-650 m). The higher P/B at intermediate depths found along N are likely due to higher % of organic matter (OM) in sediments, a product of oceanographic frontal systems. In particular, P/B was higher along N among omnivores and detritus feeders (e.g. Andaniexis mimonectes, Lepechinella manco and combined cumaceans), coupled to enriched OM in sediments, while along S

  18. Ulva (Chlorophyta, Ulvales) Biodiversity in the North Adriatic Sea (Mediterranean, Italy): Cryptic Species and New Introductions.

    PubMed

    Wolf, Marion A; Sciuto, Katia; Andreoli, Carlo; Moro, Isabella

    2012-12-01

    Ulva Linnaeus (Ulvophyceae, Ulvales) is a genus of green algae widespread in different aquatic environments. Members of this genus show a very simple morphology and a certain degree of phenotypic plasticity, heavily influenced by environmental conditions, making difficult the delineation of species by morphological features alone. Most studies dealing with Ulva biodiversity in Mediterranean waters have been based only on morphological characters and a modern taxonomic revision of this genus in the Mediterranean is not available. We report here the results of an investigation on the diversity of Ulva in the North Adriatic Sea based on molecular analyses. Collections from three areas, two of which subject to intense shipping traffic, were examined, as well as historical collections of Ulva stored in the Herbarium Patavinum of the University of Padova, Italy. Molecular analyses based on partial sequences of the rbcL and tufA genes revealed the presence of six different species, often with overlapping morphologies: U. californica Wille, U. flexuosa Wulfen, U. rigida C. Agardh, U. compressa Linnaeus, U. pertusa Kjellman, and one probable new taxon. U. californica is a new record for the Mediterranean and U. pertusa is a new record for the Adriatic. Partial sequences obtained from historical collections show that most of the old specimens are referable to U. rigida. No specimens referable to the two alien species were found among the old herbarium specimens. The results indicate that the number of introduced seaweed species and their impact on Mediterranean communities have been underestimated, due to the difficulties in species identification of morphologically simple taxa as Ulva.

  19. A sharp Moho step under Central and Eastern Betics, Western Mediterranean region

    NASA Astrophysics Data System (ADS)

    de Lis Mancilla, Flor; Aguilera-Molina, Antonio; Heit, Benjamin; Morales, Jose; Yuan, Xiaohui; Stich, Daniel; Martin, Rosa

    2016-04-01

    Previous geophysical studies in the northern limit of the western Mediterranean region have showed that the Iberian crust understrusts the Alboran domain under its contact with the External zones. They observe the presence of slab-type feature of Iberian lithosphere at the western Betics and interpret tearing and delamination of this Iberian slab at central and eastern Betics. To map the variations of the lithospheric structure between the different geological domains under central and eastern Betics, we deploy two dense seismic profiles (~120 and ~160 km length). The spacing between stations, around 2-3 km, allows mapping with high accuracy variations of the crustal structure. By interpreting P-receiver functions, we observe sharp Moho steps of ~15-17 km underneath the Internal zones (Alboran domain) at both profiles. The images suggest that the Iberian crust undertrusts the more deformed Alboran crust and terminates sharply under the contact between the Alpujarride and the Nevado-Filabre complexes (Alboran domain). The thickness of the Iberian crust near the edge, ~17 km, and its position along the contact suggest that the breaking of the Iberian slab occurs in the transitional crust of the Iberian Paleomargin.

  20. Pleistocene phylogeography and cryptic diversity of a tiger beetle, Calomera littoralis, in North-Eastern Mediterranean and Pontic regions inferred from mitochondrial COI gene sequences

    PubMed Central

    Rewicz, Tomasz; Płóciennik, Mateusz; Grabowski, Michał

    2016-01-01

    Background. Calomera littoralis is a Palearctic species, widely distributed in Europe; inhabiting predominantly its Atlantic, Mediterranean and Black Sea coastlines. Methods. Its phylogeography on the Balkan Peninsula and on the north-western Black Sea coast was inferred using a 697 bp long portion of the mitochondrial COI gene, amplified from 169 individuals collected on 43 localities. Results. The results revealed two genetically divergent groups/lineages, the southern one inhabiting both the Balkan Peninsula and the Pontic Region and the northern one found exclusively in the Pontic Region. Species delimitation based on DNA barcoding gap suggested an interspecific level of divergence between these groups. Multivariate analysis of eight male and female morphometric traits detected no difference between the groups, implying they may represent cryptic species. The Bayesian time-calibrated reconstruction of phylogeny suggested that the lineages diverged ca. 2.3 Ma, in early Pleistocene. Discussion. The presence of the two genetically divergent groups results most likely from contemporary isolation of the Pontic basin from the Mediterranean that broke the continuous strip of coastal habitats inhabited by C. littoralis. Demographic analyses indicated that both lineages have been in demographic and spatial expansion since ca. 0.15 Ma. It coincides with the terminal stage of MIS-6, i.e., Wartanian/Saalian glaciation, and beginning of MIS-5e, i.e., Eemian interglacial, during which, due to eustatic sea level rise, a wide connection between Mediterranean and the Pontic basin was re-established. This, along with re-appearance of coastal habitats could initiate north-east expansion of the southern lineage and its secondary contact with the northern one. The isolation of the Pontic basin from the Mediterranean during the Weichselian glaciation most likely did not have any effect on their phylogeography. PMID:27547517

  1. Pleistocene phylogeography and cryptic diversity of a tiger beetle, Calomera littoralis, in North-Eastern Mediterranean and Pontic regions inferred from mitochondrial COI gene sequences.

    PubMed

    Jaskuła, Radomir; Rewicz, Tomasz; Płóciennik, Mateusz; Grabowski, Michał

    2016-01-01

    Background. Calomera littoralis is a Palearctic species, widely distributed in Europe; inhabiting predominantly its Atlantic, Mediterranean and Black Sea coastlines. Methods. Its phylogeography on the Balkan Peninsula and on the north-western Black Sea coast was inferred using a 697 bp long portion of the mitochondrial COI gene, amplified from 169 individuals collected on 43 localities. Results. The results revealed two genetically divergent groups/lineages, the southern one inhabiting both the Balkan Peninsula and the Pontic Region and the northern one found exclusively in the Pontic Region. Species delimitation based on DNA barcoding gap suggested an interspecific level of divergence between these groups. Multivariate analysis of eight male and female morphometric traits detected no difference between the groups, implying they may represent cryptic species. The Bayesian time-calibrated reconstruction of phylogeny suggested that the lineages diverged ca. 2.3 Ma, in early Pleistocene. Discussion. The presence of the two genetically divergent groups results most likely from contemporary isolation of the Pontic basin from the Mediterranean that broke the continuous strip of coastal habitats inhabited by C. littoralis. Demographic analyses indicated that both lineages have been in demographic and spatial expansion since ca. 0.15 Ma. It coincides with the terminal stage of MIS-6, i.e., Wartanian/Saalian glaciation, and beginning of MIS-5e, i.e., Eemian interglacial, during which, due to eustatic sea level rise, a wide connection between Mediterranean and the Pontic basin was re-established. This, along with re-appearance of coastal habitats could initiate north-east expansion of the southern lineage and its secondary contact with the northern one. The isolation of the Pontic basin from the Mediterranean during the Weichselian glaciation most likely did not have any effect on their phylogeography. PMID:27547517

  2. Comparison data for Seasat altimetry in the western North Atlantic

    NASA Technical Reports Server (NTRS)

    Cheney, R. E.

    1981-01-01

    The radar altimeter flown on Seasat in 1978 collected approximately 1,000 orbits of high quality data (5-8 precision). In the western North Atlantic these data were combined with a detailed gravimetric geoid in an attempt to produce profiles of dynamic topography. In order to provide a basis for evaluation of these profiles, available oceanographic observations in the Gulf Stream/Sargasso Sea region have been compiled into a series of biweekly maps. The data include XBT's, satellite infrared imagery, and selected trajectories of surface drifters and sub-surface SOFAR floats. The maps document the known locations of the Gulf Stream, cyclonic and anticyclonic rings, and mid-ocean eddies during the period July to October 1978.

  3. Morphometric features as tribal predictors in north-western Amazonia.

    PubMed

    Milton, K

    1983-01-01

    Multivariate analyses of variance were carried out on stature and weight of 50 adults (25 males, 25 females) from each of two linguistically distinct groups, Maku and Tukanoan, living sympatrically in north-western Amazonia. Results showed significant intertribal differences, with Maku (sylvan hunter-gatherers) being both shorter and lighter than their Tukanoan (riparian fisher-gardeners) conspecifics. Classification with a linear discrimination function achieved 80% accuracy. Stature or weight were equally good predictors of group for men, but for women weight rather than stature was a more powerful predictor. These data offer support for the view that some factor(s) associated with life within the equatorial forest environment appear to select for generally small body physique in humans. PMID:6638939

  4. Imaging active faulting in a region of distributed deformation from the joint clustering of focal mechanisms and hypocentres: Application to the Azores-western Mediterranean region

    NASA Astrophysics Data System (ADS)

    Custódio, Susana; Lima, Vânia; Vales, Dina; Cesca, Simone; Carrilho, Fernando

    2016-04-01

    The matching between linear trends of hypocentres and fault planes indicated by focal mechanisms (FMs) is frequently used to infer the location and geometry of active faults. This practice works well in regions of fast lithospheric deformation, where earthquake patterns are clear and major structures accommodate the bulk of deformation, but typically fails in regions of slow and distributed deformation. We present a new joint FM and hypocentre cluster algorithm that is able to detect systematically the consistency between hypocentre lineations and FMs, even in regions of distributed deformation. We apply the method to the Azores-western Mediterranean region, with particular emphasis on western Iberia. The analysis relies on a compilation of hypocentres and FMs taken from regional and global earthquake catalogues, academic theses and technical reports, complemented by new FMs for western Iberia. The joint clustering algorithm images both well-known and new seismo-tectonic features. The Azores triple junction is characterised by FMs with vertical pressure (P) axes, in good agreement with the divergent setting, and the Iberian domain is characterised by NW-SE oriented P axes, indicating a response of the lithosphere to the ongoing oblique convergence between Nubia and Eurasia. Several earthquakes remain unclustered in the western Mediterranean domain, which may indicate a response to local stresses. The major regions of consistent faulting that we identify are the mid-Atlantic ridge, the Terceira rift, the Trans-Alboran shear zone and the north coast of Algeria. In addition, other smaller earthquake clusters present a good match between epicentre lineations and FM fault planes. These clusters may signal single active faults or wide zones of distributed but consistent faulting. Mainland Portugal is dominated by strike-slip earthquakes with fault planes coincident with the predominant NNE-SSW and WNW-ESE oriented earthquake lineations. Clusters offshore SW Iberia are

  5. The influence of oceanographic scenarios on the population dynamics of demersal resources in the western Mediterranean: Hypothesis for hake and red shrimp off Balearic Islands

    NASA Astrophysics Data System (ADS)

    Massutí, Enric; Monserrat, Sebastià; Oliver, Pere; Moranta, Joan; López-Jurado, José Luis; Marcos, Marta; Hidalgo, Manuel; Guijarro, Beatriz; Carbonell, Aina; Pereda, Pilar

    2008-06-01

    The aim of the present paper is to study the relationships between some climatic indices and parental stock, recruitment and accessibility to trawl fishery of hake ( Merluccius merluccius) and red shrimp ( Aristeus antennatus) off Balearic Islands (western Mediterranean). Available annual catch per unit effort, recruitment and spawning stock biomass have been used as biological data. As environmental data, the meso-scale IDEA index and the large-scale North Atlantic Oscillation (NAO) and Mediterranean Oscillation (MO) indices have been used. To analyze possible links between these indices with the population dynamics of demersal resources, two non-linear approaches have been applied: (i) stock-recruitment relationships from Ricker and Beverton-Holt models, by sequentially incorporating environment factors; (ii) generalized additive modelling, both classical general and threshold non-additive models were considered. The latter simulate an abrupt change in explicative variables across different phases (time periods or climatic index values). The results have shown that two oceanographic scenarios around the Balearic Islands, associated with macro and meso-scale climate regimes, can influence the population dynamics of hake and red shrimp. This is especially true for recruitment, which seems to be enhanced during low NAO and IDEA indices periods. During these periods, colder-than-normal winters generate high amounts of cold Western Mediterranean Intermediate Waters (WIW) in the Gulf of Lions, which flow southwards and reach the Balearic Islands channels in spring, increasing the productivity in the area. This oceanographic scenario could also be favourable to the distribution of hake on the fishing grounds where the trawl fleet targets this species, increasing its accessibility to the fishery. Both spawning stock and abundance of red shrimp seems to be also enhanced by high MO index periods, which could reflect the increased presence of the saline and warm Levantine

  6. Widespread Triploidy in Western North American Aspen (Populus tremuloides)

    PubMed Central

    Mock, Karen E.; Callahan, Colin M.; Islam-Faridi, M. Nurul; Shaw, John D.; Rai, Hardeep S.; Sanderson, Stewart C.; Rowe, Carol A.; Ryel, Ronald J.; Madritch, Michael D.; Gardner, Richard S.; Wolf, Paul G.

    2012-01-01

    We document high rates of triploidy in aspen (Populus tremuloides) across the western USA (up to 69% of genets), and ask whether the incidence of triploidy across the species range corresponds with latitude, glacial history (as has been documented in other species), climate, or regional variance in clone size. Using a combination of microsatellite genotyping, flow cytometry, and cytology, we demonstrate that triploidy is highest in unglaciated, drought-prone regions of North America, where the largest clone sizes have been reported for this species. While we cannot completely rule out a low incidence of undetected aneuploidy, tetraploidy or duplicated loci, our evidence suggests that these phenomena are unlikely to be significant contributors to our observed patterns. We suggest that the distribution of triploid aspen is due to a positive synergy between triploidy and ecological factors driving clonality. Although triploids are expected to have low fertility, they are hypothesized to be an evolutionary link to sexual tetraploidy. Thus, interactions between clonality and polyploidy may be a broadly important component of geographic speciation patterns in perennial plants. Further, cytotypes are expected to show physiological and structural differences which may influence susceptibility to ecological factors such as drought, and we suggest that cytotype may be a significant and previously overlooked factor in recent patterns of high aspen mortality in the southwestern portion of the species range. Finally, triploidy should be carefully considered as a source of variance in genomic and ecological studies of aspen, particularly in western U.S. landscapes. PMID:23119006

  7. Widespread triploidy in Western North American aspen (Populus tremuloides).

    PubMed

    Mock, Karen E; Callahan, Colin M; Islam-Faridi, M Nurul; Shaw, John D; Rai, Hardeep S; Sanderson, Stewart C; Rowe, Carol A; Ryel, Ronald J; Madritch, Michael D; Gardner, Richard S; Wolf, Paul G

    2012-01-01

    We document high rates of triploidy in aspen (Populus tremuloides) across the western USA (up to 69% of genets), and ask whether the incidence of triploidy across the species range corresponds with latitude, glacial history (as has been documented in other species), climate, or regional variance in clone size. Using a combination of microsatellite genotyping, flow cytometry, and cytology, we demonstrate that triploidy is highest in unglaciated, drought-prone regions of North America, where the largest clone sizes have been reported for this species. While we cannot completely rule out a low incidence of undetected aneuploidy, tetraploidy or duplicated loci, our evidence suggests that these phenomena are unlikely to be significant contributors to our observed patterns. We suggest that the distribution of triploid aspen is due to a positive synergy between triploidy and ecological factors driving clonality. Although triploids are expected to have low fertility, they are hypothesized to be an evolutionary link to sexual tetraploidy. Thus, interactions between clonality and polyploidy may be a broadly important component of geographic speciation patterns in perennial plants. Further, cytotypes are expected to show physiological and structural differences which may influence susceptibility to ecological factors such as drought, and we suggest that cytotype may be a significant and previously overlooked factor in recent patterns of high aspen mortality in the southwestern portion of the species range. Finally, triploidy should be carefully considered as a source of variance in genomic and ecological studies of aspen, particularly in western U.S. landscapes.

  8. Long-range Transport of Aerosol at a Mountain Site in the Western Mediterranean Basin

    NASA Astrophysics Data System (ADS)

    Roberts, Greg; Corrigan, Craig; Ritchie, John; Pont, Véronique; Claeys, Marine; Sciare, Jean; Dulac, François

    2016-04-01

    The Mediterranean Region has been identified as sensitive to changes in the hydrological cycle, which could affect the water resources for millions of people by the turn of the century. However, prior to recent observations, most climate models have not accounted for the impacts of aerosol in this region. Past airborne studies have shown that aerosol sources from Europe and Africa are often transported throughout the lower troposphere; yet, because of their complex vertical distribution, it is a challenge to capture the variability and quantify the contribution of these sources to the radiative budget and precipitation processes. The PAEROS ChArMEx Mountain Experiment (PACMEx) complemented the regional activities by collecting aerosol data from atop a mountain on the island of Corsica, France in order to assess boundary layer / free troposphere atmospheric processes. In June/July 2013, PACMEx instruments were deployed at 2000 m.asl near the center of Corsica, France to complement ground-based aerosol observations at 550 m.asl on the northern peninsula, as well as airborne measurements. Comparisons between the peninsula site and the mountain site show similar general trends in aerosol properties; yet, differences in aerosol properties reveal the myriad transport mechanisms over the Mediterranean Basin. Using aerosol physicochemical data coupled with back trajectory analysis, different sources have been identified including Saharan dust transport, residual dust mixed with sea salt, anthropogenic emissions from Western Europe, and a period of biomass burning from Eastern Europe. Each period exhibits distinct signatures in the aerosol related to transport processes above and below the boundary layer. In addition, the total aerosol concentrations at the mountain site revealed a strong diurnal cycling the between the atmospheric boundary layer and the free troposphere, which is typical of mountain-top observations. PACMEx was funded by the National Science Foundation

  9. Transport and Evolution of Aerosol Above/Below the Boundary Layer in the Western Mediterranean Basin

    NASA Astrophysics Data System (ADS)

    Roberts, G. C.; Corrigan, C.; Ritchie, J.; Pont, V.; Claeys, M.; Sciare, J.; Mallet, M.; Dulac, F.

    2014-12-01

    The Mediterranean Region has been identified as sensitive to changes in the hydrological cycle, which could affect the water resources for millions of people by the turn of the century. However, prior to recent observations, most climate models have not accounted for the impacts of aerosol in this region. Past airborne studies have shown that aerosol sources from Europe and Africa are often transported throughout the lower troposphere; yet, because of their complex vertical distribution, it is a challenge to capture the variability and quantify the contribution of these sources to the radiative budget and precipitation processes. The PAEROS ChArMEx Mountain Experiment (PACMEx) complemented the regional activities of the ChArMEx/ADRIMED summer 2013 campaign by collecting aerosol data from atop a mountain on the island of Corsica, France in order to assess boundary layer / free troposphere atmospheric processes. In June/July 2013, PACMEx instruments were deployed at 2000 m.asl near the center of Corsica to complement ground-based aerosol observations at 550 m.asl on the northern peninsula, as well as airborne measurements. Comparisons between the peninsula site and the mountain site show similar general trends in aerosol properties; yet, differences in aerosol properties reveal the myriad transport mechanisms over the Mediterranean Basin. Using aerosol physicochemical data coupled with back trajectory analysis, different sources have been identified including Saharan dust transport, residual dust mixed with sea salt, anthropogenic emissions from Western Europe, and a period of biomass burning from Eastern Europe. Each period exhibits distinct signatures in the aerosol related to transport processes above and below the boundary layer. In addition, the total aerosol concentrations at the mountain site revealed a strong diurnal cycling between the atmospheric boundary layer and the free troposphere, which is typical of mountain-top observations. PACMEx was funded by the

  10. Life history of the deep-sea cephalopod family Histioteuthidae in the western Mediterranean

    NASA Astrophysics Data System (ADS)

    Quetglas, Antoni; de Mesa, Aina; Ordines, Francesc; Grau, Amàlia

    2010-08-01

    The life cycle of the two species of the deep-sea family Histioteuthidae inhabiting the Mediterranean Sea ( Histioteuthis reversa and Histioteuthis bonnellii) was studied from monthly samples taken throughout the year during daytime hours by bottom trawl gears. A small sample of individuals found floating dead on the sea surface was also analyzed. Both species were caught exclusively on the upper slope at depths greater than 300 m. Their frequency of occurrence increased with depth and showed two different peaks, at 500-600 m and 600-700 m depth in H. bonnellii and H. reversa, respectively, which might indicate spatial segregation. Maturity stages were assigned using macroscopic determination and confirmed with histological analyses. Although mature males were caught all year round, no mature females were found, which suggests that their sexual maturation in the western Mediterranean takes place deeper than the maximum depth sampled (800 m). In fact, the increase in mean squid size with increasing depth in H. reversa indicates an ontogenetic migration to deeper waters. The individuals of both species found floating dead on the sea surface were spent females which had a relatively large cluster of small atresic eggs and a small number of remaining mature eggs scattered in the ovary and mantle cavity. The sizes of these females were clearly larger than the largest individuals caught with bottom trawls. A total of 12 and 7 different types of prey, belonging to three major taxonomic groups (crustaceans, osteichthyes and cephalopods), were identified in the stomach contents of H. reversa and H. bonnellii, respectively. In both species fishes were by far the main prey followed by crustaceans, whereas cephalopods were found only occasionally. The preys identified, mainly myctophids and natantian crustaceans, indicate that both histioteuthids base their diet on pelagic nictemeral migrators.

  11. Multi-platform operational validation of the Western Mediterranean SOCIB forecasting system

    NASA Astrophysics Data System (ADS)

    Juza, Mélanie; Mourre, Baptiste; Renault, Lionel; Tintoré, Joaquin

    2014-05-01

    The development of science-based ocean forecasting systems at global, regional, and local scales can support a better management of the marine environment (maritime security, environmental and resources protection, maritime and commercial operations, tourism, ...). In this context, SOCIB (the Balearic Islands Coastal Observing and Forecasting System, www.socib.es) has developed an operational ocean forecasting system in the Western Mediterranean Sea (WMOP). WMOP uses a regional configuration of the Regional Ocean Modelling System (ROMS, Shchepetkin and McWilliams, 2005) nested in the larger scale Mediterranean Forecasting System (MFS) with a spatial resolution of 1.5-2km. WMOP aims at reproducing both the basin-scale ocean circulation and the mesoscale variability which is known to play a crucial role due to its strong interaction with the large scale circulation in this region. An operational validation system has been developed to systematically assess the model outputs at daily, monthly and seasonal time scales. Multi-platform observations are used for this validation, including satellite products (Sea Surface Temperature, Sea Level Anomaly), in situ measurements (from gliders, Argo floats, drifters and fixed moorings) and High-Frequency radar data. The validation procedures allow to monitor and certify the general realism of the daily production of the ocean forecasting system before its distribution to users. Additionally, different indicators (Sea Surface Temperature and Salinity, Eddy Kinetic Energy, Mixed Layer Depth, Heat Content, transports in key sections) are computed every day both at the basin-scale and in several sub-regions (Alboran Sea, Balearic Sea, Gulf of Lion). The daily forecasts, validation diagnostics and indicators from the operational model over the last months are available at www.socib.es.

  12. Living on the Edge: Demography of the Slender-Billed Gull in the Western Mediterranean

    PubMed Central

    Sanz-Aguilar, Ana; Tavecchia, Giacomo; Afán, Isabel; Ramírez, Francisco; Doxa, Aggeliki; Bertolero, Albert; Gutiérrez-Expósito, Carlos; Forero, Manuela G.; Oro, Daniel

    2014-01-01

    Small and peripheral populations are typically vulnerable to local extinction processes but important for the metapopulation dynamics of species. The Slender-billed gull (Chroicocephalus genei) is a long-lived species breeding in unstable ephemeral coastal habitats. Their Western Mediterranean populations are relatively small and represent the edge of their global geographical distribution. At a local scale, using long-term data (14 years) on annual breeding success and capture-resights of marked individuals, we estimated and compared the vital rates and evaluated the connectivity of two Spanish populations (Ebro Delta and Doñana) varying in their local environmental conditions. At a metapopulation scale, we analyzed 22 years of data on breeding numbers to predict their future prospects by means of population demographic models. Local survival and breeding success of gulls from the Ebro Delta was lower than those from Doñana, which is likely the result of higher permanent emigration and/or winter mortality in the former. Gulls from the Ebro Delta wintered mostly in Mediterranean areas whereas those from Doñana did so in Atlantic coasts, where food availability is higher. Whereas adult local survival was constant, juvenile local survival showed temporal parallel variations between colonies, probably related to natal dispersal to other breeding colonies. Our results suggested that dispersal was higher at the Ebro Delta and gulls emigrating from their natal colonies settled preferentially in close patches. We found large fluctuations in breeding numbers among local populations probably related to the fact that the Slender-billed gull is a species adapted to unstable and unpredictable habitats with high abilities to disperse between suitable patches depending on environmental stochastic conditions during breeding. PMID:24664115

  13. Organotin contamination in sediments from the Western Mediterranean enclosures following 10 years of TBT regulation.

    PubMed

    Díez, S; Abalos, M; Bayona, J M

    2002-02-01

    Organotin (OT) compounds, namely butyl and phenyl, were measured in 38 recent sediments collected in harbours of the Western Mediterranean Sea (Northern: 4 and Southern: 9) and domestic and industrial sewage disposal sites (Northern: 9 and Southern: 1). Butyltins were the predominant tin species identified as being tributyltin (TBT) widespread in the whole area which suggests recent inputs of OTs. The highest levels of TBT were detected in commercial harbours associated with inputs from large vessels (average value: 5.0 microg TBT g(-1). Moreover, relatively high TBT values were also detected in fishing and recreational boating areas (average level ca. 1.0 microg TBTg(-1)). Phenyltin derivatives occurred at lower levels than butyltins being the monophenyltin the predominant compound (average values 45-945 ng g(-1)). The large predominance of the phenyltin degradation products (i.e. mono and diphenyltin) over the parent compound (i.e. triphenyltin) suggests that there are almost no recent inputs of these compounds. Furthermore, a comparative study of the OT occurrence in the sewage sludge disposal sites offshore Barcelona and Almeria (domestic) and into the Tarragona harbour (industrial) shows that domestic primary sewage sludge effluents can contribute to coastal OT pollution (244ng TBT g(-1)). Nevertheless, sewage sludge is a secondary source of OT contamination in the coastal environment in comparison to commercial harbours. In a comparative study with previous data collected in the late 1980s, the present study reveals that OT regulations established in the Mediterranean region in 1991 on the use of TBT-based antifouling paints have been effective in marinas, but reveals a significant TBT contamination in commercial and fishing harbours. PMID:11848361

  14. First report of Gyrodactylus spp. (Platyhelminthes: Monogenea) in the western Mediterranean Sea: molecular and morphological descriptions.

    PubMed

    Huyse, T; Pampoulie, C; Audenaert, V; Volckaert, F A M

    2006-08-01

    The Gyrodactylus spp. fauna on species of gobies, Pomatoschistus, Gobiusculus, and Knipowitschia (Gobiidae: Teleostei), from the western Mediterranean and Adriatic seas is strikingly similar to that found in the Baltic Sea and eastern Atlantic Ocean, both in morphology and in internal transcribed spacer (ITS) rRNA. The fauna consisted of Gyrodactylus branchialis, G. ostendicus, G. gondae, G. rugiensis, G. rugiensoides, and G. arcuatus. No new species have been found. A morphometric comparison between G. branchialis from the Mediterranean and Adriatic seas and its type locality in Ostend (Belgium) showed significant differences in ventral bar and marginal hook features. The morphometric variation was lower in G. rugiensis, whereas no significant differences were found in G. ostendicus. Gyrodactylus branchialis and G. ostendicus collected on P. microps were slightly different in the ITS rDNA (-0.6%) compared with specimens on the closely related P. marmoratus, probably reflecting ongoing speciation. A hybrid zone was identified in the Vaccarès lagoon complex (France) where both host species are sympatric. There was no clear geographic or host-related pattern in the variation found in the ITS2 rDNA in G. arcuatus sampled from P. microps, G. flavescens, Pungitius pungitius, K. panizzae, and its original host Gasterosteus aculeatus (2 polymorphic sites). Of all studied species, only G. arcuatus, G. rugiensis, and G. rugiensoides showed minor intraspecific variation in the ITS rDNA. Hence, the physical separation by a shoreline of more than 10,000 km is hardly reflected in the parasite ITS rDNA.

  15. Vertical distribution, diversity and assemblages of mesopelagic fishes in the western Mediterranean

    NASA Astrophysics Data System (ADS)

    Olivar, M. P.; Bernal, A.; Molí, B.; Peña, M.; Balbín, R.; Castellón, A.; Miquel, J.; Massutí, E.

    2012-04-01

    The mesopelagic fish community of the western Mediterranean was studied during two cruises carried out in December 2009 and July 2010 in the shelf and slope zones around the Balearic Islands. Much of what was previously known about this deep water group of fishes in the Mediterranean Sea came from studies performed using planktonic and small midwater nets. This study was the first attempt to use large pelagic trawls and small nets combined with information about the main sound scattering layers to analyse mesopelagic fish composition, diversity and species assemblages. This community is characterised by a relatively low diversity compared to other oceanic regions of the world, with Myctophiformes and Stomiiformes being the main contributors. Bathymetry and the level of the water column were the most important factors structuring the investigated fish assemblages, and similar vertical patterns were observed for the different species collected during the two study periods. A shelf assemblage composed of a few species of myctophids, with Notoscopelus elongatus being the main contributor, was distinguished. The slope assemblage included both Myctophiformes and Stomiiformes that showed differences in their day-night main location along the water column. In terms of species behaviour, two important groups were detected. The first was non-migrant or weakly migrant species, with the paradigmatic example being the gonostomatid Cyclothone braueri, which occurred at a depth of 400-600 m; this species is partly responsible for the permanent acoustic (38 kHz) response at this depth. The second group, near-surface migrants at night, was represented by most of the juvenile and adult myctophids, exemplified by Ceratoscopelus maderensis, with the exception of just a few of the largest size classes of some species, such as Lampanyctus crocodilus and N. elongatus that remain near the bottom.

  16. Fog water collection and reforestation at mountain locations in a western Mediterranean basin region

    NASA Astrophysics Data System (ADS)

    Valiente, Ja; Estrela, Mj; Corell, D.; Fuentes, D.; Valdecantos, A.

    2010-07-01

    Previous studies carried out by the authors have shown the potential of fog water collection at several mountain locations in the Valencia region (western Mediterranean basin). This coastal region features typical conditions for a dry Mediterranean climate characterized by a pluviometric regime ranging from 400 to 600 mm with a strong annual dependence. Dry conditions together with land degradation that frequently results after recurrent fires occurred in the past make a difficult self-recovery for native forest vegetation so that some kind of human intervention is always recommended. In plots reforested with Mediterranean woody species, periods of more than 120 days without significant precipitation (>5 mm) result in mortality rates above 80% during the first summer in the field. The good potential of fog-water collection at certain mountain locations is considered in this study as an easily available water resource for the reforestation of remote areas where native vegetation cannot be reestablished by itself. A large flat panel made of UV-resistant HD-polyethylene monofilament mesh was deployed at a mountain location for bulk fog water harvesting. Water was stored in high-capacity tanks for the whole length of the experimental campaign and small timely water pulses localized deep in the planting holes were conducted during the summer dry periods. Survival rates and seedling performance of two forest tree species, Pinus pinaster and Quercus ilex, were quantified and correlated to irrigation pulses in a reforestation plot that took an area of about 2500 m2 and contained 620 1-year-old plants. Before and concurrently to the flat panel deployment, a passive omnidirectional fog-water collector of cylindrical shape was set in the area in combination to other environmental instruments such as a rain gauge, a wind direction and velocity sensor and a temperature and humidity probe. Proper orientation of the large flat panel was possible once the direction of local winds

  17. Strain partitioning along the western margin of North America

    NASA Astrophysics Data System (ADS)

    Pearson, Christopher F.; Snay, R. A.

    2014-07-01

    This paper describes an elastic block model for the interseismic horizontal crustal velocity field occurring in that part of the United States located west of longitude 100° W and between latitudes 31°N and 49°N. We developed the model by simultaneously inverting 6873 GPS-derived velocity vectors and 166 geological fault slip rates for the angular velocities (i.e. the Euler poles relative to the North America plate) of 46 elastic blocks, horizontal strain rate tensors for 38 of these blocks, and the spatially variable elastic coupling coefficients on faults that bound adjacent blocks. While the model covers all of the western United States located between Canada and Mexico, this paper focuses on the region residing south of Cape Mendocino where plate boundary deformation is accommodated predominantly by slip on the San Andreas fault system. Block strain rates (which account for deformation associated with distributed faults within blocks) are systematically higher in blocks located in the western part of the model and adjacent to the plate boundary. Strain rate magnitudes range from over 10-7/yr for some blocks adjacent to the San Andreas fault system to values of about 10-9/yr for blocks located in eastern Nevada and western Utah. Blocks adjacent to the San Andreas fault system are characterized by strain rate tensors that correspond to uniaxial contraction perpendicular to the local strike of the San Andreas. The highest rates of fault normal contraction are associated with the northern end of the fault (north of San Francisco) and in the southern end (south of Los Angeles). The central San Andreas (including the creeping segment of the fault) is characterized by strain rate tensors more consistent with dextral shear. Thus the northern and southern ends of the fault are consistent with a transpressional strain partitioning model with strike slip occurring on the San Andreas fault system and distributed shortening occurring within the blocks adjacent to this

  18. Mercury and methylmercury in aquatic sediment across western North America.

    PubMed

    Fleck, Jacob A; Marvin-DiPasquale, Mark; Eagles-Smith, Collin A; Ackerman, Joshua T; Lutz, Michelle A; Tate, Michael; Alpers, Charles N; Hall, Britt D; Krabbenhoft, David P; Eckley, Chris S

    2016-10-15

    Large-scale assessments are valuable in identifying primary factors controlling total mercury (THg) and monomethyl mercury (MeHg) concentrations, and distribution in aquatic ecosystems. Bed sediment THg and MeHg concentrations were compiled for >16,000 samples collected from aquatic habitats throughout the West between 1965 and 2013. The influence of aquatic feature type (canals, estuaries, lakes, and streams), and environmental setting (agriculture, forest, open-water, range, wetland, and urban) on THg and MeHg concentrations was examined. THg concentrations were highest in lake (29.3±6.5μgkg(-1)) and canal (28.6±6.9μgkg(-1)) sites, and lowest in stream (20.7±4.6μgkg(-1)) and estuarine (23.6±5.6μgkg(-1)) sites, which was partially a result of differences in grain size related to hydrologic gradients. By environmental setting, open-water (36.8±2.2μgkg(-1)) and forested (32.0±2.7μgkg(-1)) sites generally had the highest THg concentrations, followed by wetland sites (28.9±1.7μgkg(-1)), rangeland (25.5±1.5μgkg(-1)), agriculture (23.4±2.0μgkg(-1)), and urban (22.7±2.1μgkg(-1)) sites. MeHg concentrations also were highest in lakes (0.55±0.05μgkg(-1)) and canals (0.54±0.11μgkg(-1)), but, in contrast to THg, MeHg concentrations were lowest in open-water sites (0.22±0.03μgkg(-1)). The median percent MeHg (relative to THg) for the western region was 0.7%, indicating an overall low methylation efficiency; however, a significant subset of data (n>100) had percentages that represent elevated methylation efficiency (>6%). MeHg concentrations were weakly correlated with THg (r(2)=0.25) across western North America. Overall, these results highlight the large spatial variability in sediment THg and MeHg concentrations throughout western North America and underscore the important roles that landscape and land-use characteristics have on the MeHg cycle. PMID:27130329

  19. An Overview of the DAURE Campaign: Aerosols Emissions and Evolution in the Western Mediterranean Basin

    NASA Astrophysics Data System (ADS)

    Pandolfi, Marco; Querol, Xavier; Alastuey, Andrés.; Jimenez, Jose L.

    2010-05-01

    DAURE (Determination of the sources of atmospheric Aerosols in Urban and Rural Environments in the western Mediterranean) is a multidisciplinary international measurement campaign mainly aimed at estimating the sources and origin of atmospheric fine aerosols in the Western Mediterranean Basin (WMB), with particular attention to the carbonaceous fraction. Main focuses of the campaign are the study of the origin of the intense pollution episodes frequently occurring at regional scale in summer and winter in the WMB (Perez et al., 2008) and the emission, formation, transport and transformation of aerosols during these polluted scenarios. The peculiar atmospheric dynamics in the WMB, regulated by complex climatic and orographic effects (Millán et al., 1997), together with the large pollutant emissions from densely populated areas, large industrial areas and ports located along the coastline, give rise to a complex phenomenology for aerosol formation and transformation. In this context, extremely high concentrations of fine particulate matter (mainly PM1, particulate matter with aerodynamic diameter < 1um) are usually registered at regional background stations, with levels even higher than those simultaneously registered at urban stations. DAURE brings together state-of-the-art measurements and modeling techniques from about 20 International and Spanish Institutions. The DAURE campaign took place during winter (February-March 2009) and summer (July 2009) at an urban site (Barcelona, 80 m a.s.l., NE Spain) and a regional background site (Montseny, 720 m a.s.l., NE Spain, a Supersite of the EUSAAR network). Widespread in situ aerosol sampling techniques (such as PM optical counters, PM samplers, MAAP, CPC, SMPS, Rotating Drum Impactor, among others) and remote sensing techniques (LIDAR, sunphotometer) have been applied together with state-of-the-art methods such as 14C (Szidat et al., 2006), Proton-Transfer Reaction Mass Spectrometry (PTRMS) for VOCs, and High

  20. NEAMWave12: The First Tsunami Exercise in the North-eastern Atlantic, the Mediterranean and Connected Seas

    NASA Astrophysics Data System (ADS)

    Necmioglu, Ocal; Matias Matias, Luis; Schindelé, François; Behrens, Jörn; Tinti, Stefano; Chouliaras, Gerasimos; Melis, Nicos; Carrilho, Fernando; Santoro, Francesca; Rudloff, Alexander; Crochet, Emilie; Gonzalez, Mauricio

    2013-04-01

    The first tsunami exercise of the Tsunami Early Warning and Mitigation System in the North-eastern Atlantic, the Mediterranean and connected seas (NEAMTWS) has been conducted on 27-28 November 2012 involving 19 of the 39 member countries of the Intergovernmental Coordination Group (ICG) for NEAMTWS. NEAMWave12 involved the simulation of the assessment of a tsunami, based on an earthquake-driven scenario followed by alert message dissemination by Candidate Tsunami Watch Provider (CTWP) (Phase A) and continued with the simulation of the National Tsunami Warning Center's/Tsunami Warning Focal Point's (NTWC/TWFP) and Civil Protection Authoritie's (CPA) actions (Phase B), as soon as the message produced in Phase A has been received. There were four earthquake triggered tsunami scenarios in NEAMWave12 in different parts of the NEAM Region, where each CTWP (CENALT-France, NOA-Greece, IPMA-Portugal and KOERI-Turkey) was responsible for a single scenario. The CENALT Scenario was based on a plausible worst-case scenario of magnitude 7.5 along the Western Mediterranean Algerian margin at a fault located close to 21-22 August 1856 Jijel earthquakes. The NOA scenario was based on an earthquake similar to the well-known Amorgos earthquake, which was followed by a tsunami that devastated the Aegean Sea on 9 July 1956. The IPMA scenario was based on the 1 November 1755 Lisbon event with the assumption that the event represents the worst-case tsunami scenario impacting the NE Atlantic region. Finally, the KOERI scenario was based on a Mw=8.4 worst-case interpretation of the 8 August 1303 Crete and Dodecanese Islands earthquake resulting in destructive inundation in the Eastern Mediterranean. Initial evaluation of the exercise indicates that all CTWPs successfully participated in the exercise, where existing operational and some future prototype systems were utilized. System end-users (NTWC/TWFP/CPA) benefited from the exercise considerably, demonstrating the first successful test

  1. Towards understanding the influence of environmental conditions on demersal resources and ecosystems in the western Mediterranean: Motivations, aims and methods of the IDEADOS project

    NASA Astrophysics Data System (ADS)

    Massutí, E.; Olivar, M. P.; Monserrat, S.; Rueda, L.; Oliver, P.

    2014-10-01

    The multidisciplinary IDEADOS project funded by the Spanish Government was developed between 2009 and 2012 aiming to determine the relationships between environmental conditions and the nekto-benthic slope communities in two areas of the western Mediterranean, north and south of the Balearic Islands, with different geomorphologic and hydrodynamic characteristics. In this paper we describe the background and goals of this project, its study area and the sampling strategy applied, as well as the main conclusions reached in a final workshop. This volume is a compendium of the main contributions presented at this workshop, which have been peer-reviewed and can represent the state of the art of the complex interactions between the pelagic domain and the slope benthic communities, within the context of the hydrodynamics and oligotrophy of the Balearic Islands, and considering different temporal scales and organization levels.

  2. An integrated geophysical study of north African and Mediterranean lithospheric structure

    NASA Astrophysics Data System (ADS)

    Dial, Paul Joseph

    1998-07-01

    This dissertation utilizes gravity and seismic waveform modeling techniques to: (1) determine models of lithospheric structure across northern African through gravity modeling and (2) determine lithospheric and crustal structure and seismic wave propagation characteristics across northern Africa and the Mediterranean region. The purpose of the gravity investigation was to construct models of lithospheric structure across northern Africa through the analysis of gravity data constrained by previous geological and geophysical studies. Three lithospheric models were constructed from Bouguer gravity data using computer modeling, and the gravity data was wavelength-filtered to investigate the relative depth and extent of the structures associated with the major anomalies. In the Atlas Mountains area, the resulting earth models showed slightly greater crustal thickness than those of previous studies if a low density mantle region is not included in the models. However, if a low density mantle region (density = 3.25 g/cm3) was included beneath the Atlas, the earth models showed little crustal thickening (38 km), in accord with previous seismic studies. The second portion of the research consisted of seismic waveform modeling of regional and teleseismic events to determine crustal and lithospheric structure across northern Africa and the Mediterranean. A total of 174 seismograms (145 at regional distances (200--1400 km) and 29 with epicentral distances exceeding 1900 km) were modeled using 1-D velocity models and a reflectivity code. At regional distances from four stations surrounding the western Mediterranean basin (MAL, TOL, PTO and AQU) and one station near the Red Sea (HLW), 1-D velocity models can satisfactorily model the relative amplitudes of both the Pnl and surface wave portions of the seismograms. Modeling of propagation paths greater than 1900 km was also conducted across northern Africa and the Mediterranean. The results indicate that the S-wave velocity model

  3. First evidence for an earthquake-induced tsunami and tsunamites in the western Mediterranean: the 1522 Almera earthquake

    NASA Astrophysics Data System (ADS)

    Betzler, C.; Reicherter, K.; Huebscher, C. P.; Becker-Heidmann, P.

    2005-12-01

    The 1522 Almeri-a earthquake (M > 6.5) affected large areas in the western Mediterranean and caused more than 2500 causalities. Different epicentral areas have been suspected, mainly along the 50 km long sinistral Carboneras Fault Zone (CFZ), however no on-shore surface ruptures and paleoseismological evidences for this event have been found. High-resolution sea floor imaging (narrow beam sediment profiler) yields evidence for an offshore rupture along a strand of the CFZ that is supported by evaluation of historic documents. We present a new isoseist map of the 1522 Almeri-a earthquake. Based on these data, a new epicentral area precisely at the observed sea floor rupture area is proposed at N 36°42', W 2°23' in the Gulf of Almeri-a. Drilling in lagunas and salinas of the near-by Cabo de Gata area proved sedimentary evidence for paleo-tsunamis along the Spanish Mediterranean coast. Several coarse grained intervals with fining-up and thinning-up sequences, rip-off clasts, shells of lamellibranchs and foraminifera show erosive bases. The coarse-grained intervals show up to three sequences divided from the next one by a small clayey layer. These intervals are interpreted as tsunamites. We have also found multiple intercalations of those coarse grained layers downhole, which is interpreted as either an expression of repeated earthquake activity or tsunami-like waves induced by submarine slides triggered seismic shaking in the Gulf of Almeri-a. The coast of southern Spain, the Costa de Sol, is one of the touristic hot spots in the Mediterranean Europe and very densely populated. Hence, the impact on the vulnerability is of great concern for society and economy, considering destructive earthquakes in costal residential and industrial areas, especially a holiday and recreation area in the western Mediterranean region. Our evidence suggests a certain tsunami potential and hazard for offshore active and seismogenic faults in the western Mediterranean region.

  4. Sedimentological imprint on subseafloor microbial communities in Western Mediterranean Sea Quaternary sediments

    NASA Astrophysics Data System (ADS)

    Ciobanu, M.-C.; Rabineau, M.; Droz, L.; Révillon, S.; Ghiglione, J.-F.; Dennielou, B.; Jorry, S.-J.; Kallmeyer, J.; Etoubleau, J.; Pignet, P.; Crassous, P.; Vandenabeele-Trambouze, O.; Laugier, J.; Guégan, M.; Godfroy, A.; Alain, K.

    2012-09-01

    An interdisciplinary study was conducted to evaluate the relationship between geological and paleoenvironmental parameters and the bacterial and archaeal community structure of two contrasting subseafloor sites in the Western Mediterranean Sea (Ligurian Sea and Gulf of Lion). Both depositional environments in this area are well-documented from paleoclimatic and paleooceanographic point of views. Available data sets allowed us to calibrate the investigated cores with reference and dated cores previously collected in the same area, and notably correlated to Quaternary climate variations. DNA-based fingerprints showed that the archaeal diversity was composed by one group, Miscellaneous Crenarchaeotic Group (MCG), within the Gulf of Lion sediments and of nine different lineages (dominated by MCG, South African Gold Mine Euryarchaeotal Group (SAGMEG) and Halobacteria) within the Ligurian Sea sediments. Bacterial molecular diversity at both sites revealed mostly the presence of the classes Alphaproteobacteria, Betaproteobacteria and Gammaproteobacteria within Proteobacteria phylum, and also members of Bacteroidetes phylum. The second most abundant lineages were Actinobacteria and Firmicutes at the Gulf of Lion site and Chloroflexi at the Ligurian Sea site. Various substrates and cultivation conditions allowed us to isolate 75 strains belonging to four lineages: Alpha-, Gammaproteobacteria, Firmicutes and Actinobacteria. In molecular surveys, the Betaproteobacteria group was consistently detected in the Ligurian Sea sediments, characterized by a heterolithic facies with numerous turbidites from a deep-sea levee. Analysis of relative betaproteobacterial abundances and turbidite frequency suggested that the microbial diversity was a result of main climatic changes occurring during the last 20 ka. Statistical direct multivariate canonical correspondence analyses (CCA) showed that the availability of electron acceptors and the quality of electron donors (indicated by age

  5. Rapid inundation estimates using coastal amplification laws in the Western Mediterranean basin

    NASA Astrophysics Data System (ADS)

    Gailler, Audrey; Hébert, Hélène; Schindelé, François

    2016-04-01

    Numerical tsunami propagation and inundation models are well developed and have now reached an impressive level of accuracy, especially in locations such as harbors where the tsunami waves are mostly amplified. In the framework of tsunami warning under real-time operational conditions, the main obstacle for the routine use of such numerical simulations remains the slowness of the numerical computation, which is strengthened when detailed grids are required for the precise modeling of the coastline response of an individual harbor. Thus only tsunami offshore propagation modeling tools using a single sparse bathymetric computation grid are presently included within the French Tsunami Warning Center (CENALT), providing rapid estimation of tsunami impact at Western Mediterranean and NE Atlantic basins scale. We present here a work that performs quick estimates of the coastal impact at individual harbors from these high sea forecasting tsunami simulations. The method involves an empirical correction based on the Green's theoretical amplification law. The main limitation is that its application to a given coastal area would require a large database of previous observations, in order to define the empirical parameters of the correction equation. As no tide gage records of significant tsunamis are available for the Western Mediterranean French coasts, we use a set of points of interest distributed along these coasts, where maximum water heights are calculated for both fake events and well-known historical tsunamigenic earthquakes in the area. This synthetic dataset is obtained through accurate numerical tsunami propagation and inundation modeling by using several nested bathymetric grids of increasingly fine resolution close to the shores. Non linear shallow water tsunami modeling performed on a single 2' coarse bathymetric grid are compared to the values given by time-consuming nested grids simulations, in order to check to which extent the simple approach based on the

  6. Wave ensemble forecast in the Western Mediterranean Sea, application to an early warning system.

    NASA Astrophysics Data System (ADS)

    Pallares, Elena; Hernandez, Hector; Moré, Jordi; Espino, Manuel; Sairouni, Abdel

    2015-04-01

    The Western Mediterranean Sea is a highly heterogeneous and variable area, as is reflected on the wind field, the current field, and the waves, mainly in the first kilometers offshore. As a result of this variability, the wave forecast in these regions is quite complicated to perform, usually with some accuracy problems during energetic storm events. Moreover, is in these areas where most of the economic activities take part, including fisheries, sailing, tourism, coastal management and offshore renewal energy platforms. In order to introduce an indicator of the probability of occurrence of the different sea states and give more detailed information of the forecast to the end users, an ensemble wave forecast system is considered. The ensemble prediction systems have already been used in the last decades for the meteorological forecast; to deal with the uncertainties of the initial conditions and the different parametrizations used in the models, which may introduce some errors in the forecast, a bunch of different perturbed meteorological simulations are considered as possible future scenarios and compared with the deterministic forecast. In the present work, the SWAN wave model (v41.01) has been implemented for the Western Mediterranean sea, forced with wind fields produced by the deterministic Global Forecast System (GFS) and Global Ensemble Forecast System (GEFS). The wind fields includes a deterministic forecast (also named control), between 11 and 21 ensemble members, and some intelligent member obtained from the ensemble, as the mean of all the members. Four buoys located in the study area, moored in coastal waters, have been used to validate the results. The outputs include all the time series, with a forecast horizon of 8 days and represented in spaghetti diagrams, the spread of the system and the probability at different thresholds. The main goal of this exercise is to be able to determine the degree of the uncertainty of the wave forecast, meaningful

  7. Concentrations and patterns of organochlorine pesticides and PCBs in Mediterranean monk seals (Monachus monachus) from Western Sahara and Greece.

    PubMed

    Borrell, Assumpció; Cantos, Gemma; Aguilar, Alex; Androukaki, Eugenia; Dendrinos, Panagiotis

    2007-08-01

    Blubber from Mediterranean monk seals (Monachus monachus) from the Western Sahara coast (Atlantic), sampled during 1996-1999, and from the Greek coast (Mediterranean), sampled during 1995-1999, was analyzed for organochlorine pollutants (OCs). In both populations, no significant difference was found between sexes. In the Atlantic population, mature females presented greater percentages of higher chlorinated PCB (polychlorinated biphenyl) congeners in relation to total PCBs (sum of 25 congeners) than pups, indicating a differential transfer of PCB congeners through lactation. In the Mediterranean, the reduced sample size of adult individuals precluded proper statistical investigation of age-related variation. Significant differences in concentrations and pollutant patterns were found between populations. Thus, Mediterranean individuals presented significantly higher levels of HCB (hexachlorobenzene), tPCB, and DDTs (dichlorodiphenyltrichloroethane) concentrations and DDE/tDDT and tDDT/tPCB ratios than their counterparts from the Atlantic. Moreover, the relative proportion of different congeners in relation to the total PCB load (congener/tPCB) was also different between the two areas. The 100*tDDT/tPCB ratio in Atlantic seals was 38.46, which indicates a predominance of industrial inputs over those associated with agriculture. Conversely, in the Mediterranean seal population, the 100*tDDT/tPCB ratio was 177.1, denoting a proportionally higher contribution of pollutants of agricultural origin. PMID:17499843

  8. Sea surface temperature variability in the central-western Mediterranean Sea during the last 2700 years: a multi-proxy and multi-record approach

    NASA Astrophysics Data System (ADS)

    Cisneros, Mercè; Cacho, Isabel; Frigola, Jaime; Canals, Miquel; Masqué, Pere; Martrat, Belen; Casado, Marta; Grimalt, Joan O.; Pena, Leopoldo D.; Margaritelli, Giulia; Lirer, Fabrizio

    2016-04-01

    This study presents the reconstructed evolution of sea surface conditions in the central-western Mediterranean Sea during the late Holocene (2700 years) from a set of multi-proxy records as measured on five short sediment cores from two sites north of Minorca (cores MINMC06 and HER-MC-MR3). Sea surface temperatures (SSTs) from alkenones and Globigerina bulloides Mg / Ca ratios are combined with δ18O measurements in order to reconstruct changes in the regional evaporation-precipitation (E-P) balance. We also revisit the G. bulloides Mg / Ca-SST calibration and re-adjusted it based on a set of core-top measurements from the western Mediterranean Sea. Modern regional oceanographic data indicate that Globigerina bulloides Mg / Ca is mainly controlled by seasonal spring SST conditions, related to the April-May primary productivity bloom in the region. In contrast, the alkenone-SST signal represents an integration of the annual signal. The construction of a robust chronological framework in the region allows for the synchronization of the different core sites and the construction of "stacked" proxy records in order to identify the most significant climatic variability patterns. The warmest sustained period occurred during the Roman Period (RP), which was immediately followed by a general cooling trend interrupted by several centennial-scale oscillations. We propose that this general cooling trend could be controlled by changes in the annual mean insolation. Even though some particularly warm SST intervals took place during the Medieval Climate Anomaly (MCA), the Little Ice Age (LIA) was markedly unstable, with some very cold SST events mostly during its second half. Finally, proxy records for the last centuries suggest that relatively low E-P ratios and cold SSTs dominated during negative North Atlantic Oscillation (NAO) phases, although SSTs seem to present a positive connection with the Atlantic Multidecadal Oscillation (AMO) index.

  9. Joint analysis of continental and regional background environments in the Western Mediterranean: PM1 and PM10 concentrations and composition

    NASA Astrophysics Data System (ADS)

    Ripoll, A.; Minguillón, M. C.; Pey, J.; Pérez, N.; Querol, X.; Alastuey, A.

    2014-06-01

    The complete chemical composition of atmospheric particulate matter (PM1 and PM10) from a continental (Montsec, MSC, 1570 m a.s.l.) and a regional (Montseny, MSY, 720 m a.s.l.) background site in the Western Mediterranean Basin (WMB) were jointly studied for the first time for a relatively long-term series (January 2010-March 2013). Differences on average PM concentration and composition and on seasonal variation between both sites were attributed to: distance to anthropogenic sources, altitude, height evolution of the planetary boundary layer (PBL) throughout the year, variations in the air mass origin, and changes in meteorology. The diverse meteorological episodes showed different influence at regional and continental scale. When long-range transport from Central and Eastern Europe and from North Africa occurs, the continental background site is frequently more influenced, thus indicating a preferential transport at high altitude layers. Conversely, the regional background was more influenced by regional processes. In winter, anticyclonic conditions enhance the stagnation of air masses with the consequent accumulation of pollutants at regional scale in the WMB, whereas the continental background site remains in the free troposphere. Totally different conditions drive the aerosol phenomenology in summer. Weak pressure gradients and elevated insolation generate recirculation of air masses and enhances the development of the PBL, causing the aging of aerosols and incrementing pollutant concentrations over a larger area, including the continental background. This is reflected in a more similar relative composition and absolute concentrations of PM components at both regional and continental background environments in the warmer season Peculiarities of the WMB are: (a) high relevance of African dust transport and regional dust resuspension; (b) low biomass burning contribution; (c) low summer nitrate concentrations; and (d) high aerosol homogenization in summer.

  10. Wind induced energy-momentum distribution along the Ekman-Stokes layer. Application to the Western Mediterranean Sea climate

    NASA Astrophysics Data System (ADS)

    Sayol, J. M.; Orfila, A.; Oey, L.-Y.

    2016-05-01

    Wind-wave interaction in the Western Mediterranean Sea is analyzed using 16 years of model data. The mass transport and energy distribution due to wind and waves are integrated through the Ekman-Stokes layer and then spatially and seasonally analyzed. The Stokes drift is estimated from an empirical parameterization accounting for local surface wind and the significant wave height. The impact of the Stokes drift depends on wind variability at the ocean surface and also on the geographical configuration of the basin. The Western Mediterranean Sea has on average a wind energy input two times higher in winter than in summer, and the Stokes-Ekman mass transport interaction term contributes approximately 10-15% of the total wind induced transport, but at some locations the contribution is as much as 40% or more.

  11. Travertine from Egypt's Western Desert: a terrestrial proxy for North African paleohydrology and paleoclimate during the Quaternary

    NASA Astrophysics Data System (ADS)

    Jimenez, G.; Crossey, L. J.; Karlstrom, K. E.; Polyak, V. J.; Asmerom, Y.

    2013-12-01

    The 'Green Sahara' pluvial phases that overprinted North African aridity during the Pleistocene are well recognized in tropical and Mediterranean marine records. Comparatively few studies have investigated the terrestrial expression of these pluvials, though, in part because of the paucity of paleohydrology archives in the desert. In this study, we show that travertine in Egypt's Western Desert constitutes a unique terrestrial proxy for the North African hydrologic cycle. In the Western Desert, travertine (defined inclusively as chemically-precipitated continental carbonate) deposits in paleo-oasis springs during times of high hydrologic head. Since head increases as meteoric precipitation falls in southern groundwater recharge areas, large-scale travertine accumulations can record pluvial episode durations as well as their geochemical characteristics. We built a database of new and previously-published U/Th ages from five paleo-oasis areas spanning a north-south gradient through the Western Desert. Integrating this geochronology with stable isotope and 87Sr/86Sr geochemistry of travertine samples, we present a terrestrial record of North African pluvial periods for the last ~650 ka. We show that groundwater sources for travertine remain constant through space and time, implying hydrological similarity between pluvial periods. The timing of travertine deposition is inconsistent over shorter (~10 ka) timescales in the various paleo-oases, though, suggesting that local hydrology may obscure the travertine response to pluvials. However, we observe significant travertine deposition across several areas between approximately 100 to 300 ka, and 450 to 600 ka, with a hiatus in between; we interpret these depositional 'peaks' to correspond with maxima in the 400-ka component of eccentricity. Thus, contrary to prior literature, we find that travertine deposition in the Western Desert, and thus pluvial occurrence, responds to orbitally-paced changes in equatorial insolation

  12. Diet and feeding strategies of mesopelagic fishes in the western Mediterranean

    NASA Astrophysics Data System (ADS)

    Bernal, Ainhoa; Olivar, M. Pilar; Maynou, Francesc; Fernández de Puelles, M. Luz

    2015-06-01

    Myctophids, gonostomatids and sternoptychids are the most abundant teleosteans worldwide and constitute an important assemblage of the mesopelagic ecosystem, functioning as vehicles of energy and matter through trophic webs. This study concentrates on the trophic ecology of the most abundant mesopelagic fishes of the western Mediterranean (WM) based on stomach content analysis. The myctophids (in this study: Benthosema glaciale, Ceratoscopelus maderensis, Lobianchia dofleini, Myctophum punctatum, Hygophum benoiti, Hygophum hygomii, Lampanyctus crocodilus, Lampanyctus pusillus and Notoscopelus elongatus) perform extensive diel migrations across the water column, between the surface to as deep as 1000 m, interacting with plankton and micronekton at multiple depths, and generally feeding in the epipelagic layers at night. In contrast, the gonostomatids Cyclothone braueri, Cyclothone pygmaea, and the sternoptychid Argyropelecus hemigymnus remain below epipelagic layers, feeding at different times throughout the day and night. The diet composition, trophic niche breadth and prey selectivity of 11 of these fish species were determined for juvenile and adult individuals from two surveys performed in December 2009 and July 2010 in the western Mediterranean Sea. The number of prey items varied among species, e.g. Myctophum punctatum was the species with the highest feeding intensity, reaching ca. 700 prey items in a stomach, whereas the mean number of prey in Cyclothone braueri was low (usually 1 or 2 prey per stomach). A dietary shift towards larger prey was evident from juveniles to the largest and oldest adult individuals, despite trophic niche breadths did not increase with body length for any of these mesopelagic species. The diets of the small gonostomatids, sternoptychid and early juveniles of myctophids were dominated by non-calanoid copepods, ostracods, and other small zooplankton, whereas medium-sized myctophids, e.g. L. dofleini or H. benoiti, preyed mainly on

  13. Morphodynamic implications for shoreline management of the western-Mediterranean sector of Egypt

    NASA Astrophysics Data System (ADS)

    Frihy, Omran E.

    2009-09-01

    Although the western-Mediterranean coast of Egypt between Sallum and Alexandria, ~550 km long, has maintained a considerable equilibrium throughout history, developers have built traditional protective structures in an effort to form sheltered recreational beaches without taking into consideration its geomorphologic characteristics, coastal processes and their harmful impact on the coastal environment and human safety. The improper practices in this environmentally valuable region have induced us to undertake an initiative to carry out a morphodynamic analysis to provide a framework for understanding the relationship between coastal morphology and the prevailing dynamic forces. Based on the degree of natural protection or wave sheltering, the study shoreline can be categorized into four distinct morphotypical stretches: (1) high-energy wave-exposed shores and the outer margins of the rocky headlands, (2) moderate to high wave-energy beaches along semi-exposed embayments and bays mostly downdrift of the rocky headlands, (3) low-wave energy at semi-exposed headland lee-sided and pocket beaches, and (4) calm wave-sheltered enclosing water basins for safe anchorages, moorings and recreation beaches. The results deducted will have practical applications for shoreline management initiatives regarding sustained sites suitable for future beachfront development such as safe swimming conditions, sport facilities, water intakes and sheltered areas for vessels. In addition, benefits realized by the understanding of the morphodynamic processes would enhance our awareness of the significance of the role of western coast morphodynamics in supporting sustainable development via shoreline management. As far as sustainability is concerned, the selection of appropriate sites would help avoiding or minimizing the formation of the hard structures needed for creating safe recreation beaches. On a national scale, results reached could provide reliable database for information that can be

  14. Late Glacial and Holocene gravity deposits in the Gulf of Lions deep basin, Western Mediterranean

    NASA Astrophysics Data System (ADS)

    Dennielou, B.; Bonnel, C.; Sultan, N.; Voisset, M.; Berné, S.; Beaudouin, C.; Guichard, F.; Melki, T.; Méar, Y.; Droz, L.

    2003-04-01

    Recent investigations in the Gulf of Lions have shown that complex gravity processes and deposits occurred in the deep basin since the last Glacial period. Besides the largest western Mediterranean turbiditic system, Petit-Rhône deep-sea fan (PRDSF), whose built-up started at the end of Pliocene, several sedimentary bodies can be distinguished: (1) The turbiditic Pyreneo-Languedocian ridge (PLR), at the outlet of the Sète canyon network, whose activity is strongly connected to the sea level and the connection of the canyons with the rivers. It surface shows long wave-length sediment waves, probably in relation with the turbiditic overspill. (2) An acoustically chaotic unit, filling the topographic low between the PRDSF and the PLR, the Lower Interlobe Unit. Possible source areas are the Sète canyon and/or the Marti Canyon. (3) An acoustically transparent unit, below the neofan, filling the same topographic low, the Western Transparent Unit, interpreted as a debris-flow. Recent sediment cores have shown that this sedimentary is composed of folded, laminated mud, both in its northern and southern fringes. (4) The Petit-Rhône neofan, a channelized turbiditic lobe resulting from the last avulsion of the Petit-Rhône turbiditic channel and composed of two units. The lower, acoustically chaotic facies unit, corresponding to an initial stage of the avulsion, similar to the HARP facies found on the Amazon fan. The upper, transparent, slightly bedded, channel-levee shaped unit, corresponding to the channelized stage of the avulsion. (5) Up to ten, Deglacial to Holocene, thin, fine sand layers, probably originating from shelf-break sand accumulations, through the Sète canyon network. (6) Giant scours, in the southern, distal part of the neofan, possibly linked to turbiditic overflow from the neo-channel, probably corresponding to channel-lobe transition zone features (Wynn et al. 2002). Recent investigations have shown no evidence of bottom current features.

  15. The probability of tropical cyclone landfalls in Western North Pacific

    NASA Astrophysics Data System (ADS)

    Bonazzi, A.; Bellone, E.; Khare, S.

    2012-04-01

    The Western North Pacific (WNP) is the most active basin in terms of tropical cyclone and typhoon occurrences. The densely populated countries that form the western boundary of WNP basin -- e.g. China, Japan and the Philippines -- are exposed to extreme wind gusts, storm surge and fresh water flooding eventually triggered by Tropical Cyclones (TC) events. Event-based catastrophe models (hereafter cat models) are extensively used by the insurance industry to manage their exposure against low-frequency/high-consequence events such as natural catastrophes. Cat models provide their users with a realistic set of stochastic events that expands the scope of a historical catalogue. Confidence in a cat model ability to extrapolate peril and loss statistics beyond the period covered by observational data requires good agreement between stochastic and historical peril characteristics at shorter return periods. In WNP risk management practitioners are faced with highly uncertain data to base their decisions. Albeit 4 national agencies maintain best track catalogues, data are generally based on satellite imageries with very limited central pressure (CP) and maximum velocity (VMAX) measurements -- regular flight reconnaissance missions stopped in 1987. As a result differences up to 20 knots are found in estimates of VMAX from different agencies as documented in experiment IOP-10 during Typhoon Megi in 2010. In this work we present a comprehensive analysis of CP and VMAX probability distributions at landfall across the WNP basin along a set of 150 gates (100 km coast segments) based on best track catalogues from Japan Meteorological Agency, Joint Typhoon Warning Center, China Meteorological Agency and Hong Meteorological Agency. Landfall distributions are then used to calibrate a random-walk statistical track model. A long simulation of 100,000 years of statistical TC tracks will ultimately constitute the central building block of a basin-wide stochastic catalogue of synthetic TC

  16. Cottonwood Tree Rings and Climate in Western North America

    NASA Astrophysics Data System (ADS)

    Friedman, J. M.; Edmondson, J.; Griffin, E. R.; Meko, D. M.; Merigliano, M. F.; Scott, J. A.; Scott, M. L.; Touchan, R.

    2012-12-01

    In dry landscapes of interior western USA, cottonwood (Populus spp.) seedling establishment often occurs only close to river channels after floods. Where winter is sufficiently cold, cottonwoods also have distinct annual rings and can live up to 370 years, allowing us to reconstruct the long-term history of river flows and channel locations. We have analyzed the annual rate of cottonwood establishment along streams in Montana, Wyoming, Colorado, North Dakota and Idaho. Because the trees germinate next to the river, establishment rates are strongly correlated with the rate of channel migration driven by floods. Along large rivers dominated by snowmelt from the mountains, interannual variation in peak flows and cottonwood establishment is small, and century-scale variation driven by climate change is apparent. The upper Snake, Yellowstone and Green rivers all show a strong decrease in cottonwood establishment beginning in the late 1800s and continuing to the present, indicating a decrease in peak flows prior to flow regulation by large dams. This is consistent with published tree-ring studies of montane conifers showing decreases in snowpack at the same time scale. In contrast, beginning in the late 1800s cottonwood ring widths along the Little Missouri River, North Dakota show an increase in annual growth that continues into the present. Because annual growth is strongly correlated with April-July flows (r=0.69) the ring-width data suggest an increase in April-July flows at the same time tree establishment dates suggest a decrease in peak flows. These results may be reconciled by the hypothesis that increases in low temperatures have decreased snowpack while lengthening the growing season.

  17. Orbital control of the western North Pacific summer monsoon

    NASA Astrophysics Data System (ADS)

    Wu, Chi-Hua; Chiang, John C. H.; Hsu, Huang-Hsiung; Lee, Shih-Yu

    2016-02-01

    Orbital forcing exerts a strong influence on global monsoon systems, with higher summer insolation leading to stronger summer monsoons in the Northern Hemisphere. However, the associated regional and seasonal changes, particularly the interaction between regional monsoon systems, remain unclear. Simulations using the Community Earth System Model demonstrate that the western North Pacific (WNP) summer monsoon responds to orbital forcing opposite to that of other major Northern Hemisphere monsoon systems. Compared with its current climate state, the simulated WNP monsoon and associated lower-tropospheric trough is absent in the early Holocene when the precession-modulated Northern Hemisphere summer insolation is higher, whereas the summer monsoons in South and East Asia are stronger and shift farther northward. We attribute the weaker WNP monsoon to the stronger diabatic heating of the summer Asian monsoon—in particular over the southern Tibetan Plateau and Maritime Continent—that in turn strengthens the North Pacific subtropical high through atmospheric teleconnections. By contrast, the impact of the midlatitude circulation changes on the WNP monsoon is weaker when the solar insolation is higher. Prior to the present WNP monsoon onset, the upper-tropospheric East Asian jet stream weakens and shifts northward; the monsoon onset is highly affected by the jet-induced high potential vorticity intrusion. In the instance of the extreme perihelion-summer, the WNP monsoon is suppressed despite a stronger midlatitude precursor than present-day, and the midlatitude circulation response to the enhanced South Asian precipitation is considerable. These conditions indicate internal monsoon interactions of an orbital scale, implying a potential mechanistic control of the WNP monsoon.

  18. Ageostrophic Frontal Processes Controlling Phytoplankton Production in the Catalano-Balearic Sea (Western Mediterranean)

    PubMed Central

    Oguz, Temel; Macias, Diego; Tintore, Joaquin

    2015-01-01

    Buoyancy-induced unstable boundary currents and the accompanying retrograde density fronts are often the sites of pronounced mesoscale activity, ageostrophic frontal processes, and associated high biological production in marginal seas. Biophysical model simulations of the Catalano-Balearic Sea (Western Mediterranean) illustrated that the unstable and nonlinear southward frontal boundary current along the Spanish coast resulted in a strain-driven frontogenesis mechanism. High upwelling velocities of up to 80 m d-1 injected nutrients into the photic layer and promoted enhanced production on the less dense, onshore side of the front characterized by negative relative vorticity. Additional down-front wind stress and heat flux (cooling) intensified boundary current instabilities and thus ageostrophic cross-frontal circulation and augmented production. Specifically, entrainment of nutrients by relatively strong buoyancy-induced vertical mixing gave rise to a more widespread phytoplankton biomass distribution within the onshore side of the front. Mesoscale cyclonic eddies contributed to production through an eddy pumping mechanism, but it was less effective and more limited regionally than the frontal processes. The model was configured for the Catalano-Balearic Sea, but the mechanisms and model findings apply to other marginal seas with similar unstable frontal boundary current systems. PMID:26065688

  19. Polycyclic aromatic hydrocarbons in sediments and mussels of the western Mediterranean Sea

    SciTech Connect

    Baumard, P.; Budzinski, H.; Garrigues, P.

    1998-05-01

    The distribution of polycyclic aromatic hydrocarbons (PAHs) has been investigated in superficial sediments and mussels (Mytilus galloprovincialis) of the western Mediterranean sea. The analyses were performed by gas chromatography coupled to mass spectrometry (GC-MS). The PAH concentrations ranged from 1 to 20,500 ng/g in the sediments. Different molecular indices allowed differentiation between the different pollutant sources. On the French coast, PAHs originated mainly from incomplete combustion of organic matter (pyrolytic origin), whereas for some sites in Corsica and Sardinia an overimposition of petrogenic PAHs occurred. The mussel PAH concentrations ranged from 25 to 390 ng/g. The total and individual PAH bioaccumulation factors were calculated. The correlation between sediment and mussel PAH content was discussed in terms of bioavailability. It was possible to distinguish different absorption routes for the xenobiotics according to their physicochemical properties. Because the mussel distribution of phenanthrene and anthracene seems to be governed by their water solubility, these compounds were probably mainly absorbed as the water-dissolved form, whereas the heavier molecular weight PAHs (more than four aromatic rings), whose sediment and mussel concentrations are correlated with higher correlation coefficients than for phenanthrene and anthracene, were probably mainly absorbed as adsorbed on particles. Furthermore, a possible preferential biotransformation of benzo[a]pyrene over benzo[e]pyrene is discussed.

  20. Source apportionment of PM10 in the Western Mediterranean based on observations from a cruise ship

    NASA Astrophysics Data System (ADS)

    Schembari, C.; Bove, M. C.; Cuccia, E.; Cavalli, F.; Hjorth, J.; Massabò, D.; Nava, S.; Udisti, R.; Prati, P.

    2014-12-01

    Two intensive PM10 sampling campaigns were performed in the summers of 2009 and 2010 on the ship Costa Pacifica during cruises in the Western Mediterranean. Samples, mainly collected on an hourly basis, were analysed with different techniques (Particle Induced X-Ray Emission, PIXE; Energy Dispersive - X Ray Fluorescence, ED-XRF; Ion Chromatography, IC; Thermo-optical analysis) to retrieve the PM10 composition and its time pattern. The data were used for obtaining information about the sources of aerosol, with a focus on ship emissions, through apportionment using chemical marker compounds, correlation analysis and Positive Matrix Factorization (PMF) receptor modelling. For the campaign in 2010, 66% of the aerosol sulphate was found to be anthropogenic, only minor contributions of dust and sea salt sulphate were observed while the biogenic contribution, estimated based on the measurements of MSA, was found to be more important (26%), but influenced by large uncertainties. V and Ni were found to be suitable tracers of ship emissions during the campaigns. Four sources of aerosol were resolved by the PMF analysis; the source having the largest impact on PM10, BC and sulphate was identified as a mixed source, comprising emissions from ships. The correlations between sulphate and V and Ni showed the influence of ship emissions on sulphate in marine air masses. For the leg Palma-Tunis crossing a main ship route, the correlations between aerosol sulphate and V and Ni were particularly strong (r2 = 0.9 for both elements).

  1. Ageostrophic Frontal Processes Controlling Phytoplankton Production in the Catalano-Balearic Sea (Western Mediterranean).

    PubMed

    Oguz, Temel; Macias, Diego; Tintore, Joaquin

    2015-01-01

    Buoyancy-induced unstable boundary currents and the accompanying retrograde density fronts are often the sites of pronounced mesoscale activity, ageostrophic frontal processes, and associated high biological production in marginal seas. Biophysical model simulations of the Catalano-Balearic Sea (Western Mediterranean) illustrated that the unstable and nonlinear southward frontal boundary current along the Spanish coast resulted in a strain-driven frontogenesis mechanism. High upwelling velocities of up to 80 m d(-1) injected nutrients into the photic layer and promoted enhanced production on the less dense, onshore side of the front characterized by negative relative vorticity. Additional down-front wind stress and heat flux (cooling) intensified boundary current instabilities and thus ageostrophic cross-frontal circulation and augmented production. Specifically, entrainment of nutrients by relatively strong buoyancy-induced vertical mixing gave rise to a more widespread phytoplankton biomass distribution within the onshore side of the front. Mesoscale cyclonic eddies contributed to production through an eddy pumping mechanism, but it was less effective and more limited regionally than the frontal processes. The model was configured for the Catalano-Balearic Sea, but the mechanisms and model findings apply to other marginal seas with similar unstable frontal boundary current systems. PMID:26065688

  2. Ageostrophic Frontal Processes Controlling Phytoplankton Production in the Catalano-Balearic Sea (Western Mediterranean).

    PubMed

    Oguz, Temel; Macias, Diego; Tintore, Joaquin

    2015-01-01

    Buoyancy-induced unstable boundary currents and the accompanying retrograde density fronts are often the sites of pronounced mesoscale activity, ageostrophic frontal processes, and associated high biological production in marginal seas. Biophysical model simulations of the Catalano-Balearic Sea (Western Mediterranean) illustrated that the unstable and nonlinear southward frontal boundary current along the Spanish coast resulted in a strain-driven frontogenesis mechanism. High upwelling velocities of up to 80 m d(-1) injected nutrients into the photic layer and promoted enhanced production on the less dense, onshore side of the front characterized by negative relative vorticity. Additional down-front wind stress and heat flux (cooling) intensified boundary current instabilities and thus ageostrophic cross-frontal circulation and augmented production. Specifically, entrainment of nutrients by relatively strong buoyancy-induced vertical mixing gave rise to a more widespread phytoplankton biomass distribution within the onshore side of the front. Mesoscale cyclonic eddies contributed to production through an eddy pumping mechanism, but it was less effective and more limited regionally than the frontal processes. The model was configured for the Catalano-Balearic Sea, but the mechanisms and model findings apply to other marginal seas with similar unstable frontal boundary current systems.

  3. Late Miocene/Early Pliocene vertebrate fauna from Mallorca (Balearic Islands, Western Mediterranean): an update.

    PubMed

    Bover, Pere; Rofes, Juan; Bailon, Salvador; Agustí, Jordi; Cuenca-Bescós, Gloria; Torres, Enric; Alcover, Josep Antoni

    2014-03-01

    The vertebrate fossil record from the Balearic Islands (western Mediterranean) has improved considerably over the past decade, especially in Mallorca and Menorca. In Menorca, the Pliocene terrestrial fauna was updated by the discovery and description of the large-sized leporid Nuralagus, several reptiles and an amphibian. In Mallorca, paleontological exploration yielded 2 deposits with a Late Miocene/Early Pliocene chronology, Caló den Rafelino (CdR) and Na Burguesa-1 (NB-1). So far, 4 new mammalian taxa and 2 new reptiles have been identified for the CdR deposit, whereas the faunal assemblage from the recently discovered deposit (Apr 2012) of NB-1 is currently composed of, at least, 6 terrestrial mammals, 8 reptiles and an amphibian. Its faunal composition and some primitive characteristics of the obtained taxa suggest that the chronology of this deposit is slightly earlier than the CdR. The terrestrial vertebrates recorded in these 2 Mallorcan deposits are changing the view of the paleofaunal assemblage previously known for the Plio-Pleistocene of the island. Morphological characteristics displayed by some of the taxa suggest that these faunas would be at the beginning of an isolated evolution. In this paper we present a preliminary report on the fossils recovered from the NB-1 deposit, as well as some unpublished data from CdR, and we analyze the whole fauna from both Mallorcan deposits, focusing on taxonomical and paleobiogeographical aspects. PMID:24673762

  4. Hydrogen peroxide in the western Mediterranean Sea: a tracer for vertical advection

    NASA Astrophysics Data System (ADS)

    Johnson, Kenneth S.; Willason, Stewart W.; Wiesenburg, Denis A.; Lohrenz, Steven E.; Arnone, Robert A.

    1989-02-01

    Hydrogen peroxide, micronutrients, chlorophyll, primary production and light were measured at a series of stations in the western Mediterranean Sea. Hydrogen peroxide concentrations greater than 100 nmol 1 -1 were found in this region. There was a significant relationship between hydrogen peroxide and primary production rates near the surface where the light intensity was high. This link between hydrogen peroxide and biological activity may have resulted from photochemically reactive organic compounds that were excreted during photosynthesis or from the direct biological production of hydrogen peroxide. Elevated concentrations were not found in the deep chlorophyll maximum however, which indicates that high light intensities are necessary for biogenic hydrogen peroxide production in this area. Hydrogen peroxide concentrations decreased much more slowly with depth than did light. The decoupling of light and hydrogen peroxide must have been due to a combination of a slow decay rate and rapid vertical transport. However, simple calculations indicate that eddy diffusion alone could not have transported enough hydrogen peroxide to produce the effects that were seen. Large anomalies in the concentration profiles that were detected in frontal regions indicate that hydrogen peroxide can be a useful tracer of vertical transport in the upper ocean. The size of the anomalies appears to be coupled to the salinity gradient across the front, which drives the frontal circulation.

  5. Eddy properties in the Western Mediterranean Sea from satellite altimetry and a numerical simulation

    NASA Astrophysics Data System (ADS)

    Escudier, Romain; Renault, Lionel; Pascual, Ananda; Brasseur, Pierre; Chelton, Dudley; Beuvier, Jonathan

    2016-06-01

    Three different eddy detection and tracking methods are applied to the outputs of a high-resolution simulation in the Western Mediterranean Sea in order to extract mesoscale eddy characteristics. The results are compared with the same eddy statistics derived from satellite altimetry maps over the same period. Eddy radii are around 30 km in altimetry maps whereas, in the model, they are around 20 km. This is probably due to the inability of altimetry maps to resolve the smaller mesoscale in the region. About 30 eddies are detected per day in the basin with a very heterogeneous spatial distribution and relatively short lifespans (median life around 13 days). Unlike other areas of the open ocean, they do not have a preferred direction of propagation but appear to be advected by mean currents. The number of detected eddies seems to present an annual cycle when separated according to their lifespan. With the numerical simulation, we show that anticyclones extend deeper in the water column and have a more conic shape than cyclones.

  6. Comparative diversity analysis in sandy littoral ecosystems of the western Mediterranean

    NASA Astrophysics Data System (ADS)

    Colombini, I.; Fallaci, M.; Milanesi, F.; Scapini, F.; Chelazzi, L.

    2003-10-01

    A comparative faunal analysis was carried out in sandy littoral localities differing both morphologically and in human impact. The study sites were located in the western Mediterranean basin along the coasts of Morocco, Tunisia, the Maltese Islands and Italy. These were typical beach-dune ecosystems more (Smir, Morocco; Zouara, Tunisia; Burano, Italy) or less (Ir-Ramla tat-Torri, Malta and Ir-Ramla l-Hamra, Gozo) structurally developed accordingly. Species richness was evaluated using standard trapping techniques with pitfall traps along the transects perpendicular to the shoreline. Only isopods and coleopterans were used in the analysis. In each locality, an analysis was conducted on both the beach and the dune separately, and on the entire ecosystem in the two seasons (spring and autumn). Species were studied both quantitatively and qualitatively using ecological coefficients (relative abundance) and Fisher's diversity index. To evaluate the evenness of the community, Shannon-Weaver index was calculated and compared with Brillouin index. For both indices, the maximum values were computed and were used to obtain the evenness of the community through Pielou index. In addition, Simpson's dominance index was considered. Percentages of similarities between localities were analysed in the two seasons and in total using the Renkonen index. The overall analysis showed that general trends could be found for both orders that were studied and gave indications on habitat quality. The study showed that when monitoring was carried out systematically both in space and time, arthropods could be used as important tool to assess beach health.

  7. Environmental factors controlling particulate mass fluxes on the Mallorca continental slope (Western Mediterranean Sea)

    NASA Astrophysics Data System (ADS)

    Pasqual, Catalina; Amores, Angel; Flexas, M. Mar; Monserrat, Sebastià; Calafat, Antoni

    2014-10-01

    Settled material recorded by two near bottom sediment traps deployed from November 2009 to February 2011 at northern (Sóller) and southern (Cabrera) slopes of Mallorca Island (Western Mediterranean) is studied with the aim of discerning their possible origin. The total settled particulate mass fluxes (TMF) at Sóller station were found to be, on average, 2.8 times greater than at Cabrera location during the deployment period, although both time series had a similar temporal evolution. It is suggested that wind episodes affecting the entire area were the common forcing, causing a primary production enhancement and being responsible of the similar temporal behavior. The greater sediment amounts collected in Sóller are explained on the basis of two physical mechanisms: 1) a number of successive eddies generated by instabilities of the Balearic Current that are regularly observed on satellite images, some of which have been reported to reach the seabed, thus increasing near bottom velocities and causing sediment resuspension. And 2) bottom trapped waves that are evidenced from a wavelet analysis in Sóller which could affect the TFM by enhancing sediment resuspension or advecting material from the surrounding areas.

  8. Seasonal evolution of the mediterranean water propagation in the north Atlantic

    NASA Astrophysics Data System (ADS)

    Filyushkin, B. N.; Moshonkin, S. N.; Kozhelupova, N. G.

    2008-12-01

    The Climatic variability of the seasonal water exchange in the Strait of Gibraltar and the spatial structure of the tongue of the Mediterranean Waters (MW) in the Atlantic Ocean are studied. The analysis is based on the results of a numerical experiment using a 3D ocean circulation model developed at the Institute of Computational Mathematics (ICM RAS) with a resolution of the dataset over the latitude and longitude equal to 0.25 degree. The seasonal evolution of the salinity and density fields is calculated in the North Atlantic (from 20 °S, including the Mediterranean Sea) and in the Arctic Ocean (including the Bering Sea). The comparison of the model estimates with the results of field observations demonstrated good agreement. The transport of the MW into the Atlantic is close to the observed data (during the year, it varies from 1.8 Sv in the winter to 0.9 Sv in the summer). The complex pattern of the currents in the region of the MW spreading is confirmed. The alternating character of the saline MW tongue at the 1000-m level is shown for the first time. It is found that the zones of maximum salinities in the open part of the ocean coincide with the main trajectories of migration of MW lenses and the regions of their decomposition.

  9. Biodiversity of zoobenthic hard-substrate sublittoral communities in the Eastern Mediterranean (North Aegean Sea)

    NASA Astrophysics Data System (ADS)

    Antoniadou, Chryssanthi; Chintiroglou, Chariton

    2005-03-01

    The spatial dispersion of zoobenthos from sublittoral hard substrate communities in the northern part of the Aegean Sea has been studied during summer 1997 and 1998. Material was collected by SCUBA diving, by totally scraping off five replicate quadrates (400 cm 2 each) at three depth levels (15, 30, 40 m) from six sites located in Chalkidiki peninsula, plus one in Kavala Gulf. The examination of the 19,343 living specimens collected revealed the presence of 314 species. Though the multivariate analyses showed high similarity between stations, the structure of this sciaphilic algal community seems to have an increased spatial heterogeneity. Four distinct facies were recorded in accordance with the occurrence of different algal forms, the degree of hard substrate inclination and the water clarity. A short review on the biodiversity of sublittoral communities in the Mediterranean revealed the affinity between the western and the eastern basin and also among the photophilic and the sciaphilic algal communities.

  10. Acidic and alkaline precipitation in the Cilician Basin, north-eastern Mediterranean Sea.

    PubMed

    Ozsoy, T; Saydam, A C

    2000-05-15

    Samples from precipitation events collected at Erdemli during February 1996-June 1997 were analyzed to determine their particulate aluminium content, in addition to pH and conductivity measurements. Backward air mass trajectories corresponding to the rainy days were analyzed to determine potential source regions of acidic and alkaline constituents transported to the Cilician Basin. Approximately 28% of the rain samples were found to be acidic and the trajectories associated with half of the acid precipitation events were from the Mediterranean Basin and the Balkan Peninsula, while the other half were from the Anatolian mainland and local sources. Rain samples were found to be alkaline (58%), with their trajectories originating from North Africa and the Middle East. As a result of its CaCO3 content, mineral dust from these arid regions significantly increased the pH of rainwater.

  11. Phylogeography of Canada Geese (Branta canadensis) in western North America

    USGS Publications Warehouse

    Scribner, K.T.; Talbot, S.L.; Pearce, J.M.; Pierson, B. J.; Bollinger, K.S.; Derksen, D.V.

    2003-01-01

    Using molecular genetic markers that differ in mode of inheritance and rate of evolution, we examined levels and partitioning of genetic variation for seven nominal subspecies (11 breeding populations) of Canada Geese (Branta canadensis) in western North America. Gene trees constructed from mtDNA control region sequence data show that subspecies of Canada Geese do not have distinct mtDNA. Large- and small-bodied forms of Canada Geese were highly diverged (0. 077 average sequence divergence) and represent monophyletic groups. A majority (65%) of 20 haplotypes resolved were observed in single breeding locales. However, within both large- and small-bodied forms certain haplotypes occurred across multiple subspecies. Population trees for both nuclear (microsatellites) and mitochondrial markers were generally concordant and provide resolution of population and subspecific relationships indicating incomplete lineage sorting. All populations and subspecies were genetically diverged, but to varying degrees. Analyses of molecular variance, nested-clade and coalescence-based analyses of mtDNA suggest that both historical (past fragmentation) and contemporary forces have been important in shaping current spatial genetic distributions. Gene flow appears to be ongoing though at different rates, even among currently recognized subspecies. The efficacy of current subspecific taxonomy is discussed in light of hypothesized historical vicariance and current demographic trends of management and conservation concern.

  12. Neurospora in temperate forests of western North America.

    PubMed

    Jacobson, David J; Powell, Amy J; Dettman, Jeremy R; Saenz, Gregory S; Barton, Magdalen M; Hiltz, Megan D; Dvorachek, William H; Glass, N Louise; Taylor, John W; Natvig, Donald O

    2004-01-01

    The fungal genus Neurospora has a distinguished history as a laboratory model in genetics and biochemistry. The most recent milestone in this history has been the sequencing of the genome of the best known species, N. crassa. The hope and promise of a complete genome sequence is a full understanding of the biology of the organism. Full understanding cannot be achieved, however, in the absence of fundamental knowledge of natural history. We report that species of Neurospora, heretofore thought to occur mainly in moist tropical and subtropical regions, are common primary colonizers of trees and shrubs killed by forest fires in western North America, in regions that are often cold and dry. Surveys in 36 forest-fire sites from New Mexico to Alaska yielded more than 500 cultures, 95% of which were the rarely collected N. discreta. Initial characterization of genotypes both within a site and on a single tree showed diversity consistent with sexual reproduction of N. discreta. These discoveries fill important gaps in knowledge of the distribution of members of the genus on both large and small spatial scales and provide the framework for future studies in new regions and microhabitats. The overall result is that population biology and genetics now can be combined, placing the genus Neurospora in a unique position to expand its role in experimental biology as a useful model organism for ecology, population genetics and evolution.

  13. Radioactive Contamination of the North-western Black Sea Sediments

    NASA Astrophysics Data System (ADS)

    Gulin, S. B.; Polikarpov, G. G.; Egorov, V. N.; Martin, J. M.; Korotkov, A. A.; Stokozov, N. A.

    2002-03-01

    The paper deals with the input and deposition of the man-made radionuclides 137Cs, 238 Pu, 239+240Pu and 241Am introduced to the north-western Black Sea, over the last few decades, as the result of atmospheric nuclear weapons testing and the Chernobyl nuclear accident. One approach taken was to retrieve the deposition records of these radionuclides in the sediments. The deposition chronology was compared with monitoring data of the post-Chernobyl input of 137Cs to the NW Black Sea sediments from the Danube River. The partitioning of 137 Cs between suspended matter and water was traced along the salinity gradient in the Danube mixing zone. In sediments deposited in the vicinity of the Danube delta and the Dniepr estuary, the activity of Chernobyl 137Cs had reached its maximum 5 and 10 years after the accident, respectively. The activity ratio of 137Cs to 239+240Pu and 241 Am revealed a higher mobility of 137Cs in the Danube River basin compared to plutonium and americium. The percentage of particulate 137Cs and its distribution coefficient vs salinity have allowed the estimation of sedimentary scavenging and desorption of caesium in the Danube mixing zone. Comparison of the post-Chernobyl 137Cs input from the Danube to the 137Cs inventory in the adjacent Black Sea sediments showed that more than 70% of this radionuclide was deposited in the Danube-Black Sea mixing zone.

  14. Influence of the Western Pacific teleconnection pattern on Western North Pacific tropical cyclone activity

    NASA Astrophysics Data System (ADS)

    Choi, Ki-Seon; Moon, Il-Ju

    2012-09-01

    This study analyzes the characteristics of Western North Pacific (WNP) tropical cyclone (TC) activity and large-scale environments according to the Western Pacific (WP) teleconnection pattern in summer. In the positive WP phase, an anomalous cyclone and an anomalous anticyclone develop in the low and middle latitudes of the East Asia area, respectively. As a result, southeasterlies are reinforced in the northeast area of East Asia (including Korea and Japan), which facilitates the movement of TC to this area, whereas northwesterlies are reinforced in the southwest area of East Asia (including southern China and the Indochina Peninsula) which blocks the movement of TC to that area. Due to the spatial distribution of this reinforced pressure system, TCs that develop during the positive WP phase move and turn more to the northeast of the WNP than TCs which develop during the negative WP phase. The characteristics of this TC activity during the positive WP phase are associated with the upper tropospheric jet being located farther to the northeast. TCs during the negative WP phase mainly move to the west from the Philippines toward southern China and the Indochina Peninsula. Due to the terrain effect caused by the passage of TCs in mainland China, the intensity of TCs during the negative WP phase is weaker than those during the positive WP phase.

  15. Mediterranean climate patterns and wine quality in North and Central Italy

    NASA Astrophysics Data System (ADS)

    Dalu, John David; Baldi, Marina; Dalla Marta, Anna; Orlandini, Simone; Maracchi, Gianpiero; Dalu, Giovanni; Grifoni, Daniele; Mancini, Marco

    2013-09-01

    Results show that the year-to-year quality variation of wines produced in North and Central Italy depends on the large-scale climate variability, and that the wine quality improvement in the last four decades is partially due to an increase of temperature and to a decrease of precipitation in West and Central Mediterranean Europe (WME; CME). In addition, wine quality is positively correlated with air temperature throughout the entire active period of the grapevine, weakly negatively correlated with precipitation in spring, and well negatively correlated in summer and fall. The month-to-month composites of the NAO anomaly show that, in years of good quality wine, this anomaly is negative in late spring, oscillates around zero in summer, and is positive in early fall; while, in years of bad quality wine, it is positive in late spring and summer, and negative in early fall, i.e. its polarity has an opposite sign in spring and fall in good versus bad years. The composite seasonal maps show that good wines are produced when the spring jet stream over the Atlantic diverts most of the weather perturbations towards North Europe, still providing a sufficient amount of rainwater to CME; when summer warming induced by southerly winds is balanced by the cooling induced by westerly winds; and when a positive geopotential anomaly over WME shelters CME from fall Atlantic storms. Bad quality wines are produced when the jet stream favors the intrusion of the Atlantic weather perturbations into the Mediterranean. Results suggest that atmospheric pattern persistencies can be used as precursors for wine quality forecast.

  16. Mercury and methylmercury in aquatic sediment across western North America

    USGS Publications Warehouse

    Fleck, Jacob; Marvin-DiPasquale, Mark C.; Eagles-Smith, Collin A.; Ackerman, Joshua T.; Lutz, Michelle A; Tate, Michael T.; Alpers, Charles N.; Hall, Britt D.; Krabbenhoft, David P.; Eckley, Chris S.

    2016-01-01

    Large-scale assessments are valuable in identifying primary factors controlling total mercury (THg) and monomethyl mercury (MeHg) concentrations, and distribution in aquatic ecosystems. Bed sediment THg and MeHg concentrations were compiled for > 16,000 samples collected from aquatic habitats throughout the West between 1965 and 2013. The influence of aquatic feature type (canals, estuaries, lakes, and streams), and environmental setting (agriculture, forest, open-water, range, wetland, and urban) on THg and MeHg concentrations was examined. THg concentrations were highest in lake (29.3 ± 6.5 μg kg− 1) and canal (28.6 ± 6.9 μg kg− 1) sites, and lowest in stream (20.7 ± 4.6 μg kg− 1) and estuarine (23.6 ± 5.6 μg kg− 1) sites, which was partially a result of differences in grain size related to hydrologic gradients. By environmental setting, open-water (36.8 ± 2.2 μg kg− 1) and forested (32.0 ± 2.7 μg kg− 1) sites generally had the highest THg concentrations, followed by wetland sites (28.9 ± 1.7 μg kg− 1), rangeland (25.5 ± 1.5 μg kg− 1), agriculture (23.4 ± 2.0 μg kg− 1), and urban (22.7 ± 2.1 μg kg− 1) sites. MeHg concentrations also were highest in lakes (0.55 ± 0.05 μg kg− 1) and canals (0.54 ± 0.11 μg kg− 1), but, in contrast to THg, MeHg concentrations were lowest in open-water sites (0.22 ± 0.03 μg kg− 1). The median percent MeHg (relative to THg) for the western region was 0.7%, indicating an overall low methylation efficiency; however, a significant subset of data (n > 100) had percentages that represent elevated methylation efficiency (> 6%). MeHg concentrations were weakly correlated with THg (r2 = 0.25) across western North America. Overall, these results highlight the large spatial variability in sediment THg and MeHg concentrations throughout western North America and underscore the important roles that landscape and land

  17. Role of the Alboran Sea volcanic arc choking the Mediterranean to the Messinian salinity crisis and foundering biota diversification in North Africa and Southeast Iberia

    NASA Astrophysics Data System (ADS)

    Booth-Rea, Guillermo; Ranero, Cesar R.; Grevemer, Ingo

    2016-04-01

    The Mediterranean Sea desiccated ~5.96 million years ago when it became isolated from the world oceans during the Messinian salinity crisis. This event permitted the exchange of terrestrial biota between Africa and Iberia contributing to the present rich biodiversity of the Mediterranean region. The cause chocking the Mediterranean has been proposed to be tectonic uplift and dynamic topography but the driving mechanism still remains debated. We present a new wide-angle seismic profile that provides a detailed image of the thickness and seismic velocity distribution of the crust in the eastern Alboran basin. The velocity model shows a characteristic structure of a subduction-related volcanic arc with a high-velocity lower crust and a 16-18 km total-thickness igneous crust that magmatic accreted mostly between ~10-6 Ma across the eastern Alboran basin. Estimation of the isostatically corrected depth of the arc crust taking into account the original thermal structure and sediment-loading subsidence since 6 Ma places a large area of the eastern Alboran basin above sea level at the time. This estimation is supported by geophysical data showing subaereal erosional unconformities for that time. This model may explain several up-to-now-disputed features of the Messinian salinity crisis, including: the progressive isolation of the Mediterranean since 7.1 Ma with the disappearance of open marine taxa, the existence of evaporites mostly to the east of the volcanic arc, the evidence that the Gibraltar straits were not a land bridge offered by continuous Messinian open marine sediments at ODP site 976 in the western Alboran basin, the importance of southeastern Iberia and North Africa as centres of biota diversification since before the salinity crisis, and patterns of speciation irradiating from SE Iberia and the eastern Rif in some taxons.

  18. Total Mercury in Surface and Deep Waters in the Western and Eastern Mediterranean Sea

    NASA Astrophysics Data System (ADS)

    Varde', M.; Cofone, F.; Servidio, A.; Rosselli, A.; Hedgecock, I. M.; Ammoscato, I.; Mannarino, V.; Sprovieri, F.; Gensini, M.; Pirrone, N.

    2014-12-01

    In the framework of the Italian National Research Council (CNR) Med-Oceanor measurement program and as part of the Global Mercury Observation System (GMOS) objectives, we performed two cruise campaigns with the CNR's Research Vessel (RV) Urania, in the western and eastern Mediterranean Basin, in the summers of 2012 and 2013. Total Mercury (THg) concentration in seawater was systematically measured at different depths from the sea bottom to the surface. A total of 155 surface and deep seawater samples at 25 selected stations were collected during the cruise campaigns using a stainless-steel rosette system on which 24 Niskin bottles (10L) were mounted. Continuous monitoring of temperature, conductivity, salinity and oxygen with depth were obtained by CTD measurements. All fluorinated containers were cleaned prior to use following GMOS SOPs. The chemical reagents used were suitable for ultra-trace Hg analysis. After sampling, samples were preserved by adding HCl solution to the sample bottles, which were refrigerated during transportation and analyzed within four weeks of the end of the oceanographic campaign. Sea water samples were analyzed in the laboratory following the US-EPA 1631 method revision E (US-EPA, 2002). To assess the critical issues related to mercury (Hg) contamination and to prevent leakage of Hg through volatilization we used all necessary precautions for sampling, sample stabilization, preservation and subsequent analysis in the laboratory. Quality assurance and quality control were performed using transport blanks, laboratory blanks and use of seawater certified reference materials. The accuracy of the analytical procedures for the determination of THg in sea water was corroborated by participation in a global inter-laboratory comparison study for THg in natural waters. THg concentrations in surface and deep waters found in the Mediterranean basin during the last two cruise campaigns Med-Oceanor as well as the THg measurements in sea water

  19. Seasonal population dynamics of Zeuxapta seriolae (Monogenea: Heteraxinidae) parasitising Seriola dumerili (Carangidae) in the Western Mediterranean.

    PubMed

    Repullés-Albelda, Aigües; Kostadinova, Aneta; Raga, Juan Antonio; Montero, Francisco E

    2013-03-31

    We examined the seasonal and yearly population dynamics of the monogenean pathogen Zeuxapta seriolae on juvenile fish from wild populations of Seriola dumerili. The study is based on bimonthly monitoring between April, 2005 and April, 2007 off Majorca, and newly obtained monogenean population data for juvenile fish from three additional localities in the Western Mediterranean (off Alicante, Corsica and Sardinia). We documented the highest intensities and abundances of Z. seriolae, with mean abundance values similar to or higher than those reported in the single case of wild fish mortalities reported to date. There was a recurrent pattern of seasonal change in infection with Z. seriolae in the populations of S. dumerili off Majorca, with substantially higher parasite loads during the warm season (April to June). Mean parasite abundance was significantly correlated with seawater temperature and associated with higher proportions of juvenile worms in the parasite populations, thus suggesting increased transmission rates at higher temperatures. There was a significant negative association between abundance of Z. seriolae and fish length. Comparisons with the samples of younger and older fish off Majorca indicated that whereas infection parameters gradually increased in the first year of juvenile fish life, larger/older fish (>43 cm; 1+) were much lightly infected than the smaller/younger (<30 cm; 0+) juvenile fish examined in the same season. The observed increases in abundance during the warm weather months were invariably associated with sharp increases in monogenean aggregation levels and this was in contrast with the markedly low levels for both parameters during the cold season months. These data, coupled with the strong negative correlation between the levels of aggregation of Z. seriolae and mean fish total length, indicate that heavily infected individuals are being rapidly removed (i.e. within 2-3 months) from the host population thus reducing the

  20. The BIG'95 event, Balearic Islands, Western Mediterranean Sea: numerical simulation of the possibly generated tsunami

    NASA Astrophysics Data System (ADS)

    Tinti, S.; Canals, M.; Pagnoni, G.; Zaniboni, F.; Iglesias, O.; Lastras, G.

    2009-04-01

    The BIG'95 debris flow that occurred ~11 kyrs BP affected an area of about 2200 km2 of the Ebro margin, in the Western Mediterranean Sea. The debris flow originated at the upper continental slope and involved a sediment volume of ~26 km3. After a total runout of 110 km the distalmost deposits resulting from this mass movement partly filled the upper course of the Valencia Channel at 2000 m depth. Multibeam bathymetry and backscatter maps, deep-towed side scan images, high-resolution seismic reflection profiles, submarine video records, sedimentological and mass physical properties measurement on sediment cores, and in situ geotechnical tests constitute a valuable dataset providing the basis to model the landslide evolution. Different observational elements in this data set jointly with numerical modelling simulations suggest that the downslope mass movement was rather fast (i.e. peak velocities of 50 ms-1 and 20 ms-1 have been reported for the loose sediment fraction and individual blocks, respectively). It was subsequently inferred that the BIG'95 could have generated a tsunami potentially impacting the Balearic and the Spanish coasts. In this work we explore the tsunamigenic potential of the BIG'95 by applying numerical codes that have been developed by the University of Bologna Tsunami Research Team. The code UBO-BLOCK is used for the simulation of the slide motion on a Lagrangian grid moving along with the body: the mass is split into a set of interacting blocks, that conserve the volume but can change their shape. The movement of the mass on the sea bottom generates tsunami impulses that are calculated and interpolated on the static tsunami computational grid by the intermediate code UBO-TSUIMP. The tsunami propagation is computed via the code UBO-TSUFE, solving the Navier-Stokes equations in the shallow water approximation on the computational domain, constituted by triangles whose dimension depends on the local sea depth. This work has been performed in the

  1. Climate variability in the Eastern and Western Mediterranean Sea over the last two millennia: a contribution of PaleoMex/MISTRALS

    NASA Astrophysics Data System (ADS)

    Gogou, Alexandra; Sicre, Marie-Alexandrine; Triantaphyllou, Maria; Parinos, Konstantine; Bouloubassi, Ioanna; Dimiza, Margarita; Rousakis, Grigoris; Korres, Gerasimos; Kallel, Nejib; Jalali, Bassem; Kaberi, Helen; Ezat, Ullah; Lykousis, Vasilios

    2013-04-01

    Recent compilations of Mediterranean 2k paleoclimate archives (Luterbacher et al., 2012, MedClivar Book) stressed the lack of high-resolution/ continuous marine records. The two new high-resolution sea surface temperature (SSTs) time-series presented here from the shallow coastal shelf sediments of the Gulf of Lions and deeper ocean one of the Aegean Sea using alkenone paleothermometry, are thus an important contribution. SST values are roughly 2°C warmer in the Eastern than Western Mediterranean sites in agreement with our knowledge of the production pattern of the main alkenone producer Emiliania huxleyi in the two basins. Both SST-record reveal significant variability of cool/warm intervals, corresponding to the continental European and Northern Hemisphere climatic variability. While distant from each other, SSTs at the two sites show some degree of similarity: increasing SSTs from ~ 600 to 1300 AD followed by a significant cooling till the early 1600's marking the onset of an outstanding warm period reaching values similar to present day. After a sharp decrease ending around 1700 yrs AD, the last three centuries indicate gradually rising SSTs by about 1°C/100 yrs. To our knowledge the latter feature has been undocumented in North Atlantic cores but often observed in paleoclimate reconstructions of the European climate, though with different regional timing and amplitude. This unexpected finding may reflect feedbacks from the surrounding land-masses contributing to "continentalize" the Mediterranean climate. Another notable feature is the short-lived abrupt cooling in the Aegean record between 1816 and 1824 yr AD, possibly expressing the surface water cooling subsequent to the Tambora volcanic eruption of 1815 yrs AD. * We acknowledge financial support from MEDECOS (Marin-ERA, EU/FP6) Project and the Greek General Secretary of Research and Technology. Luterbacher J, Garcia-Herrera R, Allan R, Alvarez-Castro BG, Benito G, Booth J, Büntgen U, Colombaroli D

  2. Black Sea and Mediterranean Sea interaction: influence of the North Aegean dynamics

    NASA Astrophysics Data System (ADS)

    Androulidakis, Yannis; Krestenitis, Yannis; Kourafalou, Vassiliki

    2013-04-01

    The brackish Black Sea Waters outflow to the Aegean Sea, through the Dardanelles Straits, affects and determines significantly the hydrodynamic and physical characteristics of the Aegean Sea. At the same time, it affects several biological parameters, like chl-a concentrations, and, therefore, the general quality of the marine environment. The investigation and mathematical simulation of the North Aegean's physical oceanography contributes to the knowledge and understanding of the buoyant waters' circulation initial conditions in the wider East Mediterranean region. The implementation and adaptation of the 3-d hydrodynamic mathematical model HYCOM (Hybrid Coordinate Ocean Model) in the North Aegean Sea (1/50οx1/50o), significantly contributes to the investigation of the area's hydrodynamic circulation. HYCOM, due to its hybrid coordinate operation, can describe at a satisfactory level, all the different topography and mixing cases of the complicated N. Aegean region. In addition, the high resolution atmospheric forcing and the nesting with a data assimilated broader Mediterranean HYCOM model along the southern open boundary of the North Aegean model, benefit the quality of the results and constitutes an important tool on the description and understanding of the Black Sea influence to the region's dynamics. A fundamental objective is the application and comparison of different Dardanelles outflow parameterizations based a) on the Black Sea water budget, b) on current measurements from a telemetric station in Limnos Island, and c) on historical time series. The Black Sea Waters plume evolution and the circulation patterns are dependant on the outflow rate magnitude, the flow distribution inside the straits and the prevailing winds. The long-term simulation covers the period of the last 20 years (1990-2010), investigating several physical characteristics of the North Aegean Sea, such as the deep water masses evolution, the major Black Sea waters circulation patterns

  3. UHP metamorphism in the Western Mediterranean : A tale of a Tethys fragment (Edough Massif, NE Algeria) and its geodynamic consequences

    NASA Astrophysics Data System (ADS)

    Bruguier, Olivier; Bosch, Delphine; Caby, Renaud; Fernandez, Laure; Abdallah, Nachida; Arnaud, Nicolas; Hammor, Dalila; Laouar, Rabah; Mechati, Medhi; Monié, Patrick; Ouabadi, Aziouz; Toubal, Abder

    2016-04-01

    The Edough Massif of NE Algeria is part of the Maghrebides, a peri-Mediterranean Alpine belt that extends from Morocco to Tunisia. The belt resulted mainly from the eastward retreat of the Tethyan slab and from the drift of continental fragments, some of which finally collided with the north African margin. In this study we report the recent discovery of metamorphic diamonds (5-30 μm in size) included in a garnet megacryst and identified by Raman spectroscopy and the characteristic sharp band at 1332 cm‑1 for crystalline diamond. The studied megacryst was taken from a weathered actinolitite horizon inserted within a major mylonite-ultramylonite band, which outcrops at the base of an allochtonous oceanic unit thrust onto the African paleomargin. The host garnet is almandine-dominant with a sharp increase in grossular component in the rim and is rich in exsolution of small acicular rutile needles. Major and trace elements show a gradual but significant zonation from core to rim characterized by a decrease in HREE, Y and Mn, typical of a prograde growth in a closed system. Trace element analyses of large prismatic rutile (up to 300 μm) indicate that the host metamorphic rock was a mafic protolith of MORB affinity and the Zr-in-rutile thermometry indicates a temperature range of 724-778°C for rutile growth. U-Pb analyses of these large rutile crystals provide an age of 32.4 ± 3.3 Ma interpreted as dating the prograde subduction stage of the mafic protolith. Minute zircons (≤ 30μm), disseminated in the garnet, display a multifaceted appearance and low Th/U ratios consistent with a metamorphic origin. The lack of HREE depletion in these zircons indicates that their metamorphic growth was not coeval with garnet. U-Pb analyses and Ti-in-zircon thermometry indicate they nucleated at 20.9 ± 2.2 Ma during near isothermal decompression related to exhumation of the UHP units. This study allows bracketing the age of UHP metamorphism in the Western Mediterranean to the

  4. UHP metamorphism in the Western Mediterranean : A tale of a Tethys fragment (Edough Massif, NE Algeria) and its geodynamic consequences

    NASA Astrophysics Data System (ADS)

    Bruguier, Olivier; Bosch, Delphine; Caby, Renaud; Fernandez, Laure; Abdallah, Nachida; Arnaud, Nicolas; Hammor, Dalila; Laouar, Rabah; Mechati, Medhi; Monié, Patrick; Ouabadi, Aziouz; Toubal, Abder

    2016-04-01

    The Edough Massif of NE Algeria is part of the Maghrebides, a peri-Mediterranean Alpine belt that extends from Morocco to Tunisia. The belt resulted mainly from the eastward retreat of the Tethyan slab and from the drift of continental fragments, some of which finally collided with the north African margin. In this study we report the recent discovery of metamorphic diamonds (5-30 μm in size) included in a garnet megacryst and identified by Raman spectroscopy and the characteristic sharp band at 1332 cm-1 for crystalline diamond. The studied megacryst was taken from a weathered actinolitite horizon inserted within a major mylonite-ultramylonite band, which outcrops at the base of an allochtonous oceanic unit thrust onto the African paleomargin. The host garnet is almandine-dominant with a sharp increase in grossular component in the rim and is rich in exsolution of small acicular rutile needles. Major and trace elements show a gradual but significant zonation from core to rim characterized by a decrease in HREE, Y and Mn, typical of a prograde growth in a closed system. Trace element analyses of large prismatic rutile (up to 300 μm) indicate that the host metamorphic rock was a mafic protolith of MORB affinity and the Zr-in-rutile thermometry indicates a temperature range of 724-778°C for rutile growth. U-Pb analyses of these large rutile crystals provide an age of 32.4 ± 3.3 Ma interpreted as dating the prograde subduction stage of the mafic protolith. Minute zircons (≤ 30μm), disseminated in the garnet, display a multifaceted appearance and low Th/U ratios consistent with a metamorphic origin. The lack of HREE depletion in these zircons indicates that their metamorphic growth was not coeval with garnet. U-Pb analyses and Ti-in-zircon thermometry indicate they nucleated at 20.9 ± 2.2 Ma during near isothermal decompression related to exhumation of the UHP units. This study allows bracketing the age of UHP metamorphism in the Western Mediterranean to the

  5. Man-induced salinity and temperature increases in western Mediterranean deep water. (Reannouncement with new availability information)

    SciTech Connect

    Rohling, E.J.; Bryden, H.L.

    1992-07-15

    The historical data base is used to study property changes in both the Western Mediterranean Deep Water (WMDW) and the Levantine Intermediate Water (LIW). Changes in WMDW properties during the past century have been described previously, although on a more limited data base. We are not aware of any previous study of changes in LIW properties. In the extensive data base we used, increases appear in both WMDW temperature and salinity, from 1909 to the present, which substantiate previously reported observations. In addition, we find that the density of WMDW seems to have increased as well, which disagrees with previous suggestions that it has remained constant. We observe that the WMDW temperature increase displays a distinct acceleration starting about 1955 and that a similar, although less conspicuous, acceleration occurs in the WMDW salinity increase. From our study of historical data on LIW properties, the LIW salinity also appears to have increased since 1909. We argue that the warming trend in WMDW may well be a response to the salinity increase, which seems to be imported from the eastern Mediterranean by LIW, and as such our observations endorse a recently published hypothesis. The increase in LIW salinity, in turn, is attributed to changes in the eastern Mediterranean freshwater budget, resulting from damming of major rivers that drain either directly or indirectly into the eastern Mediterranean.

  6. Effects of tropical North Atlantic SST on tropical cyclone genesis in the western North Pacific

    NASA Astrophysics Data System (ADS)

    Yu, Jinhua; Li, Tim; Tan, Zhemin; Zhu, Zhiwei

    2016-02-01

    The tropical cyclone genesis number (TCGN) in July-October (JASO) over the western North Pacific (WNP) exhibits a robust interannual variation. It shows a longitudinally tri-pole pattern with a high in the eastern WNP and South China Sea (SCS) and a low in the western WNP, which explain 42.2 and 23.4 % of total TCGN variance in the eastern WNP and SCS, respectively. The high-low-high pattern is similar to that derived from a TC genesis potential index (GPI). To understand the cause of the longitudinal distribution of the dominant interannual mode, we examine the contributions of environmental parameters associated with GPI. It is found that relative humidity and relative vorticity are important factors responsible for TC variability in the SCS, while vertical shear and relative vorticity are crucial in determining TC activity in eastern WNP. A simultaneous correlation analysis shows that the WNP TCGN in JASO is significantly negatively correlated (with a correlation coefficient of -0.5) with sea surface temperature anomalies (SSTA) in the tropical North Atlantic (TNA). The longitudinal distribution of TC genesis frequency regressed onto TNA SSTA resembles that regressed upon the WNP TCGN series. The spatial patterns of regressed environmental variables onto the SSTA over the TNA also resemble those onto TCGN in the WNP, that is, an increase of relative humidity in the SCS and a weakening of vertical shear in the eastern WNP are all associated with cold SSTA in the TNA. Further analyses show that the cold SSTA in the TNA induce a negative heating in situ. In response to this negative heating, a low (upper)-level anomalous aniti-cyclonic (cyclonic) flows appear over the subtropical North Atlantic and eastern North Pacific, and to east of the cold SSTA, anomalous low-level westerlies appear in the tropical Indian Ocean. Given pronounced mean westerlies in northern Indian Ocean in boreal summer, the anomalous westerly flows increase local surface wind speed and surface

  7. Hydrodynamic modelling of coastal seas: the role of tidal dynamics in the Messina Strait, Western Mediterranean Sea

    NASA Astrophysics Data System (ADS)

    Cucco, Andrea; Quattrocchi, Giovanni; Olita, Antonio; Fazioli, Leopoldo; Ribotti, Alberto; Sinerchia, Matteo; Tedesco, Costanza; Sorgente, Roberto

    2016-07-01

    This work explores the importance of considering tidal dynamics when modelling the general circulation in the Messina Strait, a narrow passage connecting the Tyrrhenian and the Ionian subbasins in the Western Mediterranean Sea. The tides and the induced water circulation in this Strait are among the most intense oceanographic processes in the Mediterranean Sea. The quantification of these effects can be particularly relevant for operational oceanographic systems aimed to provide short-term predictions of the main hydrodynamics in the Western Mediterranean subbasins. A numerical approach based on the use of a high-resolution hydrodynamic model was followed to reproduce the tides propagation and the wind-induced and thermohaline water circulation within the Strait and in surrounding areas. A set of numerical simulations was carried out to quantify the role of the Strait dynamics on the larger-scale water circulation. The obtained results confirmed the importance of a correct representation of the hydrodynamics in the Messina Strait even when focusing on predicting the water circulation in the external sea traits. In fact, model results show that tidal dynamics deeply impact the reproduction of the instantaneous and residual circulation pattern, waters thermohaline properties and transport dynamics both inside the Messina Strait and in the surrounding coastal and open waters.

  8. Aerosol vertical distribution, optical properties and transport over Corsica (western Mediterranean)

    NASA Astrophysics Data System (ADS)

    Léon, J.-F.; Augustin, P.; Mallet, M.; Bourrianne, T.; Pont, V.; Dulac, F.; Fourmentin, M.; Lambert, D.; Sauvage, B.

    2015-03-01

    This paper presents the aerosol vertical distribution observed in the western Mediterranean between February and April 2011 and between February 2012 and August 2013. An elastic backscattering lidar was continuously operated at a coastal site in the northern part of Corsica Island (Cap Corse) for a total of more than 14 000 h of observations. The aerosol extinction coefficient retrieved from cloud-free lidar profiles are analyzed along with the SEVIRI satellite aerosol optical depth (AOD). The SEVIRI AOD was used to constrain the retrieval of the aerosol extinction profiles from the lidar range-corrected signal and to detect the presence of dust or pollution aerosols. The daily average AOD at 550 nm is 0.16 (±0.09) and ranges between 0.05 and 0.80. A seasonal cycle is observed with minima in winter and maxima in spring-summer. High AOD days (above 0.3 at 550 nm) represent less than 10% of the totality of daily observations and correspond to the large scale advection of desert dust from Northern Africa or pollution aerosols from Europe. The respective origin of the air masses is confirmed using FLEXPART simulations in the backward mode. Dust events are characterized by a large turbid layer between 2 and 5 km height while pollution events show a lower vertical development with a thick layer below 3 km in altitude. However low level dust transport is also reported during spring while aerosol pollution layer between 2 and 4 km height has been also observed. We report an effective lidar ratio at 355 nm for pollution aerosols 68 (±13) Sr while it is 63 (±18) Sr for dust. The daily mean AOD at 355 nm for dust events is 0.61 (±0.14) and 0.71 (±0.16) for pollution aerosols events.

  9. Origin of lipid biomarkers in mud volcanoes from the Alboran Sea, western Mediterranean

    NASA Astrophysics Data System (ADS)

    López-Rodríguez, C.; Stadnitskaia, A.; De Lange, G. J.; Martínez-Ruíz, F.; Comas, M.; Sinninghe Damsté, J. S.

    2013-11-01

    Mud volcanoes (MVs) are the most prominent indicators of active methane/hydrocarbon venting at the seafloor on both passive and active continental margins. Their occurrence in the Western Mediterranean is patent at the West Alboran Basin, where numerous MVs develop overlaying a major sedimentary depocenter containing overpressured shales. Although some of these MVs have been studied, the detailed biogeochemistry of expelled mud so far has not been examined in detail. This work provides the first results on the composition and origin of organic matter, Anaerobic Oxidation of Methane (AOM) processes and general characteristics on MV dynamics using lipid biomarkers as the main tool. Lipid biomarker analysis was performed on MV expelled material (mud breccias) and interbedded hemipelagic sediments from Perejil, Kalinin and Schneider's Heart MVs located in the northwest margin of the Alboran Sea. The n-alkane-distributions and n-alkane-derived indices (CPI and ACL), in combination with the epimerization degree of hopanes (22S/(22S + 22R)) indicate that all studied mud breccia have a similar biomarker composition consisting of mainly thermally immature organic matter with an admixture of petroleum-derived compounds. This concordant composition indicates that common source strata must feed all three studied MVs. The past or present AOM activity was established using lipid biomarkers specific for anaerobic methanotropic archaea (irregular isoprenoids and DGDs) and the depleted carbon isotope composition (δ13C) of crocetane/phytane. The presence of these lipid biomarkers, together with the low amounts of detected GDGTs, is consistent with the dominance of anaerobic methanotrophs of the ANME-2 over ANME-1, at least in mud breccia from Perejil MVs. In contrast, the scarce presence or lack of these AOM-related lipid biomarkers in sediments from Kalinin and Schneider's Heart MVs, suggest no recent active methane seepage has occurred at these sites. Moreover, the observed

  10. Meso-scale variability of coastal suprabenthic communities in the southern Tyrrhenian Sea (western Mediterranean)

    NASA Astrophysics Data System (ADS)

    Fanelli, E.; Cartes, J. E.; Badalamenti, F.; D'Anna, G.; Pipitone, C.; Azzurro, E.; Rumolo, P.; Sprovieri, M.

    2011-02-01

    Meso-scale spatial variability of coastal suprabenthic communities inhabiting muddy bottoms at 50-80 m depth in three gulfs of northern Sicily (Western Mediterranean) was here investigated. Although similar as concerns the hydrological and oceanographic conditions, the three areas, that encompass a large portion of the continental shelf (135 km), are characterized by different geo-morphological features. In addition, they are subjected to different trawl fishery pressures. The Gulf of Castellammare is a semi-enclosed bay, where the trawling activity has been banned since 1990. The Gulf of Termini Imerese and the Gulf of Sant'Agata are open areas, subjected to high trawl fishing intensity. In terms of density, gammarid amphipods showed differences among the three gulfs; in terms of biomass, cumaceans and amphipods were more abundant in the Gulf of Castellammare than in the other two areas. Multivariate analyses provided evidence for separation of suprabenthic assemblages between the Gulf of Castellammare and the other two gulfs. The Gulf of Castellammare seemed to host the most diversified and stable community according to α- and β-diversity indices. In the same way the low value of δ 13C vs. δ 15N correlation found in the gulf of Castellammare, which evidences the occurrence of several food sources, supports the idea of a higher stability in the semi-enclosed, trawl-ban area. In the other two areas δ 13C vs. δ 15N correlations were high, suggesting the existence of a pelagic source sustaining the suprabenthic communities. This is also confirmed by the lower δ 13C concentrations found in suprabenthic species. Taking into account the homogeneous oceanographic conditions among gulfs, other factors, such as geo-morphology and trawling pressure should be involved in the observed differences among the three areas in terms of assemblage structure, diversity, and trophodynamics of suprabenthic communities.

  11. Comparison of Western immunoblotting and microimmunofluorescence for diagnosis of Mediterranean spotted fever.

    PubMed Central

    Teysseire, N; Raoult, D

    1992-01-01

    One-hundred serum samples from 41 patients suffering from Mediterranean spotted fever (MSF) were tested by microimmunofluorescence (MIF) and Western blot (WB; immunoblot). Immunoglobulin G (IgG), IgM, and IgA antibody-specific responses to the high-molecular-mass species-specific protein antigens (115 kDa and 135 kDa) of Rickettsia conorii, as well as to cross-reactive lipopolysaccharide (LPS) antigens, were observed. The WB assay detected IgM-type antibodies earlier than did the MIF assay. These antibodies were often directed against nonspecific LPS and may have a questionable positive predictive value. In addition, an IgG reaction to a 60-kDa protein was observed in four cases of malignant forms of MSF but was never observed in cases of mild forms. This reaction could be correlated with a marker of the severity of the development of MSF. From a previous MIF survey of blood donors, 9 negative, 11 IgG-positive, and 6 IgM-positive serum samples were selected for comparison by WB. Sera negative by MIF were also negative by WB. MIF IgG-positive sera showed a specific response to R. conorii in the WB assay, but the six serum samples from this seroepidemiological study positive for IgM by MIF were almost all negative by the WB assay. One was positive for IgM against the LPS but was considered a false positive. The WB is shown to provide a new tool for serodiagnosis. Images PMID:1537916

  12. Real-time weather forecasting in the Western Mediterranean Basin: An application of the RAMS model

    NASA Astrophysics Data System (ADS)

    Gómez, I.; Caselles, V.; Estrela, M. J.

    2014-03-01

    A regional forecasting system based on the Regional Atmospheric Modeling System (RAMS) is being run at the CEAM Foundation. The model is started twice daily with a forecast range of 72 h. For the period June 2007 to August 2010 the verification of the model has been done using a series of automatic meteorological stations from the CEAM network and located within the Valencia Region (Western Mediterranean Basin). Air temperature, relative humidity and wind speed and direction of the output of the model have been compared with observations. For these variables, an operational verification has been performed by computing different statistical scores for 18 weather stations. This verification process has been carried out for each season of the year separately. As a result, it has been revealed that the model presents significant differences in the forecast of the meteorological variables analysed throughout the year. Moreover, due to the physical complexity of the area of study, the model presents different degree of accuracy between coastal and inland stations. Precipitation has also been verified by means of yes/no contingency tables as well as scatter plots. These tables have been built using 4 specific thresholds that have permitted to compute some categorical statistics. From the results found, it is shown that the precipitation forecast in the area of study is in general over-predicted, but with marked differences between the seasons of the year. Finally, dividing the available data by season of the year, has permitted us to analyze differences in the observed patterns for the magnitudes mentioned above. These results have been used to better understand the behavior of the RAMS model within the Valencia Region.

  13. Coastal and mesoscale dynamics characterization combining glider and altimetry: case study over the Western Mediterranean Sea

    NASA Astrophysics Data System (ADS)

    Jerome, Bouffard; Pascual, Ananda; Ruiz, Simon; Isabelle Pujol, Marie; Faugere, Yannice; Larnicol, Gilles; Tintore, Joaquin

    Satellite altimetry allows a direct computation of geostrophic velocity anomalies. However, conventional altimetry measurements remain largely spurious in coastal zone, due to several factors such as inaccurate geophysical corrections (e.g. atmospheric and tidal signals) as well as environmental issues (land contamination in the altimetric and radiometric footprints). At the present time and in the attempt of future relevant technologies (cf. SWOT satellite), experimen-tal coastal altimeter products are under development (XTRACK, PISTACH, COASTALT. . . ). The main efforts consist in the application of coastal-oriented corrections and the review of the data recovery strategies near the coast. The new coastal altimetric products need to be assessed with independent data before to be used in synergy with other measurements and fully exploited for scientific applications. This is the frame of this study as part of an intensive observational program conducted in the Western Mediterranean Sea. We present here the main outcomes resulting from the combination of coastal altimetry and gliders. Gliders -autonomous underwater vehicles -allow to provide precise and high resolution data complementary to altimetry (temperature, salinity, pressure, velocity. . . ) both at surface and over the whole water column. Since July 2007, several glider missions have been performed along Jason-1, Jason-2 and ENVISAT altimeters. The altimetric sea level anomalies have been processed from both standard and coastal-oriented strategies. Furthermore, new methodologies have also been developed in order to combine surface glider geostrophic velocities (derived from CTD measurements) with integrated currents estimated by the glider (derived from GPS locations every 6 hours). These approaches prove to be very efficient to improve the budget errors and homogenize the physical contents of altimetry and glider data. Further, the combined analysis of the two datasets provides interesting insights of

  14. Seismic stratigraphy, subsidence history, and tectonic evolution of the Alboran Sea, western Mediterranean

    SciTech Connect

    Watts, A.B. ); Doherty, J.I.C.; Banda, E. ); Platt, J. )

    1991-08-01

    Seismic reflection profile, gravity and geoid data, and well data have been used to examine the tectonic evolution of the Alboran Sea, a small basin in the western Mediterranean. Previous seismic refraction data suggest that the basin is underlain by stretched continental crust which thins from about 40 km beneath Iberia and Morocco to as much as 15 km in the basin center. According to commercial well data, the earliest sediments are lower Burdigalian, suggesting that extension was initiated during the early Miocene. The thinning is part of a sidespread extensional event that appears have modified the crustal structure in the Balearic, Algerian, and Valencia Trough basins to the east. In the case of the Alboran Sea basin, however, the extent to which extensional processes account for the crustal structure is obscured by the competing effects of compression due, for example, to thrust/fold loading in the flanking Betic and Rif cordillera. Backstripping of commercial wells in the Iberian margin reveals an exponentially decreasing subsidence that is similar in form to that of many rift-type basins. However, DSDP Site 121, located on a basement high in the basin center, shows an accelerating subsidence that is more typical of foreland-type basins. Recent studies in the Valencia Trough, show that the relative of extensional and compressional processes can be estimated through an integrated approach of flexural backstripping, crustal restoration, and gravity and geoid modeling along selected transects of a basin. The authors paper presents the results of such an approach to the Alboran Sea and evaluates its implications for current models for the tectonic evolution of the basin.

  15. Sensitivity analysis of runoff modeling to statistical downscaling models in the western Mediterranean

    NASA Astrophysics Data System (ADS)

    Grouillet, B.; Ruelland, D.; Ayar, P. V.; Vrac, M.

    2015-10-01

    This paper analyzes the sensitivity of a hydrological model to different methods to statistically downscale climate precipitation and temperature over four western Mediterranean basins illustrative of different hydro-meteorological situations. The comparison was conducted over a common 20 year period (1986-2005) to capture different climatic conditions in the basins. Streamflow was simulated using the GR4j conceptual model. Cross-validation showed that this model is able to correctly reproduce runoff in both dry and wet years when high-resolution observed climate forcings are used as inputs. These simulations can thus be used as a benchmark to test the ability of different statistically downscaled datasets to reproduce various aspects of the hydrograph. Three different statistical downscaling models were tested: an analog method (ANALOG), a stochastic weather generator (SWG) and the "cumulative distribution function - transform" approach (CDFt). We used the models to downscale precipitation and temperature data from NCEP/NCAR reanalyses as well as outputs from two GCMs (CNRM-CM5 and IPSL-CM5A-MR) over the reference period. We then analyzed the sensitivity of the hydrological model to the various downscaled data via five hydrological indicators representing the main features of the hydrograph. Our results confirm that using high-resolution downscaled climate values leads to a major improvement of runoff simulations in comparison to the use of low-resolution raw inputs from reanalyses or climate models. The results also demonstrate that the ANALOG and CDFt methods generally perform much better than SWG in reproducing mean seasonal streamflow, interannual runoff volumes as well as low/high flow distribution. More generally, our approach provides a guideline to help choose the appropriate statistical downscaling models to be used in climate change impact studies to minimize the range of uncertainty associated with such downscaling methods.

  16. Sensitivity analysis of runoff modeling to statistical downscaling models in the western Mediterranean

    NASA Astrophysics Data System (ADS)

    Grouillet, Benjamin; Ruelland, Denis; Vaittinada Ayar, Pradeebane; Vrac, Mathieu

    2016-03-01

    This paper analyzes the sensitivity of a hydrological model to different methods to statistically downscale climate precipitation and temperature over four western Mediterranean basins illustrative of different hydro-meteorological situations. The comparison was conducted over a common 20-year period (1986-2005) to capture different climatic conditions in the basins. The daily GR4j conceptual model was used to simulate streamflow that was eventually evaluated at a 10-day time step. Cross-validation showed that this model is able to correctly reproduce runoff in both dry and wet years when high-resolution observed climate forcings are used as inputs. These simulations can thus be used as a benchmark to test the ability of different statistically downscaled data sets to reproduce various aspects of the hydrograph. Three different statistical downscaling models were tested: an analog method (ANALOG), a stochastic weather generator (SWG) and the cumulative distribution function-transform approach (CDFt). We used the models to downscale precipitation and temperature data from NCEP/NCAR reanalyses as well as outputs from two general circulation models (GCMs) (CNRM-CM5 and IPSL-CM5A-MR) over the reference period. We then analyzed the sensitivity of the hydrological model to the various downscaled data via five hydrological indicators representing the main features of the hydrograph. Our results confirm that using high-resolution downscaled climate values leads to a major improvement in runoff simulations in comparison to the use of low-resolution raw inputs from reanalyses or climate models. The results also demonstrate that the ANALOG and CDFt methods generally perform much better than SWG in reproducing mean seasonal streamflow, interannual runoff volumes as well as low/high flow distribution. More generally, our approach provides a guideline to help choose the appropriate statistical downscaling models to be used in climate change impact studies to minimize the range

  17. Climate effects on historic bluefin tuna captures in the Gibraltar Strait and Western Mediterranean

    NASA Astrophysics Data System (ADS)

    Ganzedo, Unai; Polanco-Martínez, Josué M.; Caballero-Alfonso, Ángela M.; Faria, Sérgio H.; Li, Jianke; Castro-Hernández, José J.

    2016-06-01

    Historical capture records of bluefin tuna (Thunnus thynnus; BFT hereafter) from the Gibraltar Strait and Western Mediterranean show pronounced short- and long-term fluctuations. Some of these fluctuations are believed to be associated with biological and ecological process, as well as distinct climate factors. For the period of study (1700-1936) of this work, we found a long-term increasing trend in the BFT captures and in the climate variables. After applying a statistical time series analysis of relevant climate variables and long-term tuna capture records, it is highlighted the role played by sea-surface temperature (SST) on bluefin population variations. The most relevant result of this study is the strong correlation found between the total solar irradiance (TSI) - an external component of the climate system - and bluefin captures. The solar irradiance could have affected storminess during the period under study, mainly during the time interval 1700-1810. We suggest physico-biological mechanisms that explain the BFT catch fluctuations in two consecutive time intervals. In the first period, from 1700 to 1810, this mechanism could be high storm and wind activity, which would have made the BFT fisheries activities more difficult by reducing their efficacy. In contrast, during the interval from 1810 to 1907, the effects of wind and storms could be on spawning behaviour and larval ecology, and hence on year class strength, rather than on fish or fisherman's behaviour. These findings open up a range of new lines of enquiry that are relevant for both, fisheries and climate change research.

  18. Knowledge exchange for climate adaptation planning in western North America

    NASA Astrophysics Data System (ADS)

    Garfin, Gregg; Orr, Barron

    2015-04-01

    In western North America, the combination of sustained drought, rapid ecosystem changes, and land use changes associated with urban population growth has motivated concern among ecosystem managers about the implications of future climate changes for the landscapes which they manage. Through literature review, surveys, and workshop discussions, we assess the process of moving from concern, to planning, to action, with an emphasis on questions, such as: What are the roles of boundary organizations in facilitating knowledge exchange? Which practices lead to effective interactions between scientists, decision-makers, and knowledge brokers? While there is no "one size fits all" science communication method, the co-production of science and policy by research scientists, science translators, and decision-makers, as co-equals, is a resource intensive, but effective practice for moving adaptation planning forward. Constructive approaches make use of alliances with early adopters and opinion leaders, and make strong communication links between predictions, impacts and solutions. Resource managers need information on the basics of regional climate variability and global climate change, region-specific projections of climate changes and impacts, frank discussion of uncertainties, and opportunities for candid exploration of these topics with peers and subject experts. Research scientists play critical roles in adaptation planning discussions, because they assist resource managers in clarifying the cascade of interactions leading to potential impacts and, importantly, because decision-makers want to hear the information straight from the scientists conducting the research, which bolsters credibility. We find that uncertainty, formerly a topic to avoided, forms the foundation for constructive progress in adaptation planning. Candid exploration of the array of uncertainties, including those due to modeling, institutional, policy and economic factors, with practitioners, science

  19. On the Effects of Parameterized Mediterranean Overflow on North Atlantic Ocean Circulation and Climate

    NASA Astrophysics Data System (ADS)

    Wu, W.; Danabasoglu, G.; Large, W.

    2006-12-01

    A Mediterranean overflow parameterization has been implemented in the ocean component of the NCAR Community Climate System Model (CCSM3) to represent the sub-grid scale exchanges through the Strait of Gibraltar and associated entrainment. It is evaluated by comparing solutions from the coarse resolution (nominally 3 degree) global ocean model to observations and high resolution process model results. The properties (temperature, salinity and volume) and depths of the inflow, outflow, entrainment and product waters are all close to observed estimates and stable after 300 years of integration. The seasonal cycle of the exchange has a reasonable amplitude, but its phase is advanced by three months from summer to spring. The improvement relative to either blocking the strait, or excavating a too wide channel is demonstrated. The effects on the circulation and properties of the North Atlantic are most prominent at about 1100 m. They include the formation of a realistic salt tongue across the basin and modified currents and younger water in the eastern basin offshore of the overflow. Climate impacts were assessed by comparing fully coupled climate models with and without the overflow parameterization after 300 years. The effects on North Atlantic sea surface temperature and heat flux do not match, suggesting an atmospheric response. Only minor differences were evident in the meridional overturning circulation and the ocean heat transport.

  20. Active Tectonics of the western Mediterranean: GPS evidence for roll back of a delaminated subcontinental lithospheric slab beneath the Rif Mountains, Morocco.

    NASA Astrophysics Data System (ADS)

    Vernant, P.; Fadil, A.; McClusky, S.; Reilinger, R.; Gomez, F.; Ben Sari, D.; Mourabit, T.; Feigl, K.; Barazangi, M.

    2005-12-01

    The location and character of the Africa-Eurasia plate boundary in the western Mediterranean remain equivocal. Miocene to present extension of the interplate Alboran domain occurs within the context of ongoing Africa-Eurasia convergence. Ideas to explain the apparently synchronous subsidence of the Alboran Sea and uplift of the adjacent Betic and Rif mountain belts are still widely debated. To understand better the tectonics of this region, we determine the surface deformation in Morocco from five years of GPS survey observations of a 22-station survey network, 4 continuously recording GPS stations, and 4 IGS stations in Iberia. In addition to the expected Africa-Eurasia relative motion, the results indicate roughly southward motion (~3 mm/yr) of the Rif Mountains, Morocco relative to stable Africa. The associated crustal shortening of the Rif is balanced by extension and opening of the adjacent Alboran Sea. Motion of the Rif is approximately normal to the direction of Africa-Eurasia relative motion, and is difficult to relate to deformation induced by plate boundary interactions. We suggest that Rif-Alboran deformation is the combination of the differential plate motion between Iberia and Africa, and sub-lithospheric dynamic processes. The continental crust characterizing the Alboran region and the N-S asymmetry of the observed deformation (i.e., no evidence for north-directed shortening in the Betic Mountains north of the Alboran Sea) suggests that delamination and south-directed roll back of the African lithospheric mantle under the Rif/Alboran domain is driving the recent geologic evolution of the westernmost Mediterranean region.

  1. Interpretation of coastal sediment quality based on trace metal and PAH analysis, benthic foraminifera, and toxicity tests (Sardinia, Western Mediterranean).

    PubMed

    Schintu, Marco; Buosi, Carla; Galgani, François; Marrucci, Alessandro; Marras, Barbara; Ibba, Angelo; Cherchi, Antonietta

    2015-05-15

    An integrated approach for the assessment of coastal sediment quality was utilised in three areas of Sardinia (Western Mediterranean, Italy). Sediments were analysed for trace metals and polycyclic aromatic hydrocarbons (PAHs), while benthic foraminifera were used as bioindicators. Furthermore, the embryo-toxicity test was used to provide ecologically relevant information using rapid and cost-effective screening tools. The aim was to evaluate the usefulness of coupling different analytical tools. The results revealed the presence of polluted sediments in areas exposed to petrochemical industries, smelters or military settlements. However, while foraminifera have presented similar indications for chemical analysis of contamination levels in the different areas, the toxicity test exhibited a poor relationship with the contaminants measured individually. The results raise questions concerning the bioavailability of contaminants released by sediments in the water column. Overall, the toxicity rate was significant in many samples in comparison with other sites studied in other Mediterranean regions. PMID:25795553

  2. Multiple deformation at the western edge of the Carolina slate belt, north-central North Carolina

    SciTech Connect

    Hibbard, J.P.; Shell, G.S.; Wilkins, J.K. ); Samson, S.; Wortman, G. . Dept. of Geology)

    1994-03-01

    In north-central North Carolina, volcanic-plutonic rocks of the Carolina slate belt are separated from gneisses of the Milton belt to the west by a wide, ENE-trending, polygenetic structural zone. Within a portion of this zone, the Country Line Creek complex (CLCC) forms the western edge of the slate belt. Rocks of the CLCC span a wide age range and include mafic and granitoid gneisses with subordinate pelitic schist, granitoid pegmatite, and a concordant sheet-like intrusion, the Yanceyville metagranite. The complex is heterogeneously deformed and metamorphosed. Along the SE margin of the structural zone, steeply-dipping, strongly foliated biotite granitoid and mafic gneisses of the complex appear to be intruded by the Roxboro metagranite of the Carolina slate belt. To the NW, in more interior portions of the zone, the CLCC is affected by multiphase foliations and folds that record a dextral oblique normal shear event. Here, the Yanceyville metagranite is affected by a strong foliation that is folded. A preliminary new date on the Roxboro pluton of ca. 545 Ma, indicates a Late Precambrian or older timing of deformation along the SE margin of the zone. In contrast, a preliminary, ca. 340 Ma, age on the Yanceyville metagranite indicates multiple stage Late Paleozoic deformation for interior portions of the zone. Regional structural and isotopic data hint that the Precambrian deformation may record initial interactions between the Milton and Carolina slate belts. Subsequently, this contact was reactivated during Alleghanian orogenesis.

  3. WILD SALMON IN WESTERN NORTH AMERICA; THE HISTORICAL AND POLICY CONTEXT

    EPA Science Inventory

    Nearly all of the participants in the Salmon 2100 Project concluded that wild salmon recovery efforts in western North America (especially California, Oregon, Washington, Idaho, and southern British Columbia), as earnest, expensive, and socially disruptive as they currently are, ...

  4. WILD SALMON IN WESTERN NORTH AMERICA: FORECASTING THE MOST LIKELY STATUS IN 2100

    EPA Science Inventory

    The future of wild salmon in western North America (especially California, Oregon, Washington, Idaho, and southern British Columbia), as earnest, expensive, and socially disruptive as current recovery efforts are, does not appear likely to realize sustain biologically significan...

  5. Population structure and group composition of western lowland gorillas in north-western Republic of Congo.

    PubMed

    Magliocca, F; Querouil, S; Gautier-Hion, A

    1999-01-01

    Population studies are an essential part of conservation actions. Under exceptional observation conditions we studied a western lowland gorilla population visiting the Maya salt-clearing (north of the Parc national d'Odzala, P.N.O., Congo) over an 8 month period; 36 groups and 18 solitary individuals (a total of 420 individuals) have been identified visiting the clearing, which suggests a high gorilla density in the region. Ninety-six percent of the gorillas entered the clearing in groups. One-male groups had a mean size of 11.2. Ninety percent of solitary individuals were silver-back males. Compared with other populations of both lowland gorillas and mountain gorillas, the Maya population had the highest immature rate and the highest number of infants per female. Ecological correlates that could explain the attractiveness of the Maya clearing are discussed. The present status and the renewal rate of the Maya population indicate the need for further studies and confirm the importance of developing eco-tourism in this region as part of the sustainable park management activities developed by the ECOFAC programme (European Union). The results also provide arguments to support the proposal for extending the P.N.O. to include this region, which is rich in salt-clearings and attracts many other key-species of mammal such as forest elephants.

  6. Joint analysis of continental and regional background environments in the western Mediterranean: PM1 and PM10 concentrations and composition

    NASA Astrophysics Data System (ADS)

    Ripoll, A.; Minguillón, M. C.; Pey, J.; Pérez, N.; Querol, X.; Alastuey, A.

    2015-01-01

    The complete chemical composition of atmospheric particulate matter (PM1 and PM10) from a continental (Montsec, MSC, 1570 m a.s.l.) and a regional (Montseny, MSY, 720 m a.s.l) background site in the western Mediterranean Basin (WMB) were jointly studied for the first time over a relatively long-term period (January 2010-March 2013). Differences in average PMX concentration and composition between both sites were attributed to distance to anthropogenic sources, altitude, and different influence of atmospheric episodes. All these factors result in a continental-to-regional background increase of 4.0 μg m-3 for PM10 and 1.1 μg m-3 for PM1 in the WMB. This increase is mainly constituted by organic matter, sulfate, nitrate, and sea salt. However, higher mineral matter concentrations were measured at the continental background site owing to the higher influence of long-range transport of dust and dust resuspension. Seasonal variations of aerosol chemical components were attributed to evolution of the planetary boundary layer (PBL) height throughout the year, variations in the air mass origin, and differences in meteorology. During warmer months, weak pressure gradients and elevated insolation generate recirculation of air masses and enhance the development of the PBL, causing the aging of aerosols and incrementing pollutant concentrations over a large area in the WMB, including the continental background. This is reflected in a more similar relative composition and absolute concentrations of continental and regional background aerosols. Nevertheless, during colder months the thermal inversions and the lower vertical development of the PBL leave MSC in the free troposphere most of the time, whereas MSY is more influenced by regional pollutants accumulated under winter anticyclonic conditions. This results in much lower concentrations of PMX components at the continental background site with respect to those at the regional background site. The influence of certain

  7. The Seismic Broad Band Western Mediterranean (wm) Network and the Obs Fomar Pool: Current state and Obs activities.

    NASA Astrophysics Data System (ADS)

    Pazos, Antonio; Davila, Jose Martin; Buforn, Elisa; Bezzeghoud, Mourad; Harnafi, Mimoun; Mattesini, Mauricio; Caldeira, Bento; Hanka, Winfried; El Moudnib, Lahcen; Strollo, Angelo; Roca, Antoni; Lopez de Mesa, Mireya; Dahm, Torsten; Cabieces, Roberto

    2016-04-01

    The Western Mediterranean (WM) seismic network started in 1996 as an initiative of the Royal Spanish Navy Observatory (ROA) and the Universidad Complutense de Madrid (UCM), with the collaboration of the GeoForschungsZentrum (GFZ) of Potsdam. A first broad band seismic station (SFUC) was installed close to Cádiz (South Spain). Since then, additional stations have been installed in the Ibero-Moghrebian region. In 2005, the "WM" code was assigned by the FDSN and new partners were jointed: Evora University (UEVO, Portugal), the Scientifique Institute of Rabat (ISRABAT, Morocco), and GFZ. Now days, the WM network is composed by 15 BB stations, all of them with Streckaisen STS-2 or STS-2.5 sensors, Quanterra or Earthdata digitizers and SeiscomP. Most them have co-installed a permanent geodetic GPS stations, and some them also have an accelerometer. There are 10 stations deployed in Spanish territory (5 in the Iberian peninsula, 1 in Balearic islands and 4 in North Africa Spanish places) with VSAT or Internet communications, 2 in Portugal (one of them without real time), and 3 in Morocco (2 VSAT and 1 ADSL). Additionally, 2 more stations (one in South Spain and one in Morocco) will be installed along this year. Additionally ROA has deployed a permanent real time VBB (CMG-3T: 360s) station at the Alboran Island. Due to the fact that part of the seismic activity is located at marine areas, and also because of the poor geographic azimuthal coverage at some zones provided by the land stations (specially in the SW of the San Vicente Cape area), ROA and UCM have acquired six broad band "LOBSTERN" OBS, manufactured by KUM (Kiel, Germany), conforming the OBS FOMAR pool. Three of them with CMG-40T sensor and the other with Trillium 120. These OBS were deployed along the Gibraltar strait since January to November 2014 to study the microseismicity in the Gibraltar strait area. In September 2015 FOMAR network has been deployed in SW of the San Vicente Cape for 8 months as a part of

  8. Erosion of continental margins in the Western Mediterranean due to sea-level stagnancy during the Messinian Salinity Crisis

    NASA Astrophysics Data System (ADS)

    Just, Janna; Hübscher, Christian; Betzler, Christian; Lüdmann, Thomas; Reicherter, Klaus

    2011-02-01

    High-resolution multi-channel seismic data from continental slopes with minor sediment input off southwest Mallorca Island, the Bay of Oran (Algeria) and the Alboran Ridge reveal evidence that the Messinian erosional surface is terraced at an almost constant depth interval between 320 and 380 m below present-day sea level. It is proposed that these several hundred- to 2,000-m-wide terraces were eroded contemporaneously and essentially at the same depth. Present-day differences in these depths result from subsidence or uplift in the individual realms. The terraces are thought to have evolved during one or multiple periods of sea-level stagnancy in the Western Mediterranean Basin. According to several published scenarios, a single or multiple periods of relative sea-level stillstand occurred during the Messinian desiccation event, generally known as the Messinian Salinity Crisis. Some authors suggest that the stagnancy started during the refilling phase of the Mediterranean basins. When the rising sea level reached the height of the Sicily Sill, the water spilled over this swell into the eastern basin. The stagnancy persisted until sea level in the eastern basin caught up with the western Mediterranean water level. Other authors assigned periods of sea-level stagnancy to drawdown phases, when inflowing waters from the Atlantic kept the western sea level constant at the depth of the Sicily Sill. Our findings corroborate all those Messinian sea-level reconstructions, forwarding that a single or multiple sea-level stagnancies at the depth of the Sicily Sill lasted long enough to significantly erode the upper slope. Our data also have implications for the ongoing debate of the palaeo-depth of the Sicily Sill. Since the Mallorcan plateau experienced the least vertical movement, the observed terrace depth of 380 m there is inferred to be close to the Messinian depth of this swell.

  9. Malaria transmission in two localities in north-western Argentina

    PubMed Central

    Dantur Juri, María J; Zaidenberg, Mario; Claps, Guillermo L; Santana, Mirta; Almirón, Walter R

    2009-01-01

    Background Malaria is one of the most important tropical diseases that affects people globally. The influence of environmental conditions in the patterns of temporal distribution of malaria vectors and the disease has been studied in different countries. In the present study, ecological aspects of the malaria vector Anopheles (Anopheles) pseudopunctipennis and their relationship with climatic variables, as well as the seasonality of malaria cases, were studied in two localities, El Oculto and Aguas Blancas, in north-western Argentina. Methods The fluctuation of An. pseudopunctipennis and the malaria cases distribution was analysed with Random Effect Poisson Regression. This analysis takes into account the effect of each climatic variable on the abundance of both vector and malaria cases, giving as results predicted values named Incidence Rate Radio. Results The number of specimens collected in El Oculto and Aguas Blancas was 4224 (88.07%) and 572 (11.93%), respectively. In El Oculto no marked seasonality was found, different from Aguas Blancas, where high abundance was detected at the end of spring and the beginning of summer. The maximum mean temperature affected the An. pseudopunctipennis fluctuation in El Oculto and Aguas Blancas. When considering the relationship between the number of malaria cases and the climatic variables in El Oculto, maximum mean temperature and accumulated rainfall were significant, in contrast with Aguas Blancas, where mean temperature and humidity showed a closer relationship to the fluctuation in the disease. Conclusion The temporal distribution patterns of An. pseudopunctipennis vary in both localities, but spring appears as the season with better conditions for mosquito development. Maximum mean temperature was the most important variable in both localities. Malaria cases were influenced by the maximum mean temperature in El Oculto, while the mean temperature and humidity were significant in Aguas Blancas. In Aguas Blancas peaks of

  10. Alkalinity distribution in the western North Atlantic Ocean margins

    NASA Astrophysics Data System (ADS)

    Cai, Wei-Jun; Hu, Xinping; Huang, Wei-Jen; Jiang, Li-Qing; Wang, Yongchen; Peng, Tsung-Hung; Zhang, Xin

    2010-08-01

    Total alkalinity (TA) distribution and its relationship with salinity (S) along the western North Atlantic Ocean (wNAO) margins from the Labrador Sea to tropical areas are examined in this study. Based on the observed TA-S patterns, the mixing processes that control alkalinity distribution in these areas can be categorized into a spectrum of patterns that are bracketed by two extreme mixing types, i.e., alongshore current-dominated and river-dominated. Alongshore current-dominated mixing processes exhibit a segmented mixing line with a shared mid-salinity end-member. In such cases (i.e., Labrador Sea, Gulf of Maine, etc.), the y-intercept of the high salinity segment of the mixing line is generally higher than the local river alkalinity values, and it reflects the mixing history of the alongshore current. In contrast, in river-dominated mixing (Amazon River, Caribbean Sea, etc.), good linear relationships between alkalinity and salinity are generally observed, and the zero salinity intercepts of the TA-S regressions roughly match those of the regional river alkalinity values. TA-S mixing lines can be complicated by rapid changes in the river end-member value and by another river nearby with a different TA value (e.g., Mississippi-Atchafalaya/Gulf of Mexico). In the wNAO margins, regression intercepts and river end-members have a clear latitudinal distribution pattern, increasing from a low of ˜300 μmol kg-1 in the Amazon River plume to a high value between ˜500-1100 μmol kg-1 in the middle and high latitude margins. The highest value of ˜2400 μmol kg-1 is observed in the Mississippi River influenced areas. In addition to mixing control, biological processes such as calcification and benthic alkalinity production may also affect ocean margin alkalinity distribution. Therefore, deriving inorganic carbon system information in coastal oceans using alkalinity-salinity relationships, in particular, those of generic nature, may lead to significant errors.

  11. LLNL Middle East, North Africa and Western Eurasia Knowledge Base

    SciTech Connect

    O'Boyle, J; Ruppert, S D; Hauk, T F; Dodge, D A; Ryall, F; Firpo, M A

    2001-07-12

    The Lawrence Livermore National Laboratory (LLNL) Ground-Based Nuclear Event Monitoring (GNEM) program has made significant progress populating a comprehensive Seismic Research Knowledge Base (SRKB) and deriving calibration parameters for the Middle East, North Africa and Western Eurasia (ME/NA/WE) regions. The LLNL SRKB provides not only a coherent framework in which to store and organize very large volumes of collected seismic waveforms, associated event parameter information, and spatial contextual data, but also provides an efficient data processing/research environment for deriving location and discrimination correction surfaces. The SRKB is a flexible and extensible framework consisting of a relational database (RDB), Geographical Information System (GIS), and associated product/data visualization and data management tools. This SRKB framework is designed to accommodate large volumes of data (almost 3 million waveforms from 57,000 events) in diverse formats from many sources (both LLNL derived research and integrated contractor products), in addition to maintaining detailed quality control and metadata. We have developed expanded look-up tables for critical station parameter information (including location and response) and an integrated and reconciled event catalog data set (including specification of preferred origin solutions and associated phase arrivals) for the PDE, CMT, ISC, REB and selected regional catalogs. Using the SRKB framework, we are combining traveltime observations, event characterization studies, and regional tectonic models to assemble a library of ground truth information and phenomenology (e.g. travel-time and amplitude) correction surfaces required for support of the ME/NA/WE regionalization program. We also use the SRKB to integrate data and research products from a variety of sources, such as contractors and universities, to merge and maintain quality control of the data sets. Corrections and parameters distilled from the LLNL SRKB

  12. The role of the exchanges through the Strait of Gibraltar on the budget of elements in the Western Mediterranean Sea: consequences of human-induced modifications.

    PubMed

    Gómez, Fernando

    2003-06-01

    The role of the Strait of Gibraltar on the exchanges of substances between Mediterranean Sea and the Atlantic Ocean is reviewed. The previous estimations have been recalculated by using a similar water flux and compared with the river and atmospheric inputs to the Western Mediterranean Sea. The man-induced changes in the dimensions of the Strait of Gibraltar increasing (planning the sill) or reducing of the cross-section by a total or partial dam are discussed. A total dam will control the sea-level rise in the Mediterranean Sea, but an annual increase of major nutrient concentrations of 1-2% could be expected, lower than the rate of increase of the river and atmospheric inputs in the Western Mediterranean Sea. The increase of the cross-section of the Strait by increasing the depth (planning) at the sill could compensate the increase of the external nutrient inputs.

  13. North American Legumes for Rangeland Restoration, Conservation, and Forage Production in the Western U.S.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Land managers do not have many alternatives to choose from when seeding North American legume species on rangelands of the western U.S. As part of an initiative to address that need, research was conducted with basalt milkvetch (Astragalus filipes), western prairie clover (Dalea ornata), and Searls...

  14. Dispersion and transport of tropospheric aerosol and pollutants in the Western Mediterranean: the role of the Po Valley under different transport regimes

    NASA Astrophysics Data System (ADS)

    Bucci, Silvia; Fierli, Federico; Ravetta, François; Raut, Jean Christophe; Cristofanelli, Paolo; Decesari, Stefano; Diliberto, Luca; Größ, Johannes; Pap, Ines; Weinhold, Kay; Wiedensohler, Alfred; Cairo, Francesco

    2016-04-01

    same season, the combination of airborne measurements with transport and chemical model analysis, allowed to individuate two episodes of inversion in the main advection pattern (23th -24th June and 26th -27th June), causing an easterly pollution export from the Po basin toward the Genoa Gulf (North-Western Mediterranean). Using the CO species as a tracer of pollution, we estimated the Po Valley contribution over the local pollution background value. The CO plume affected a layer from the sea level to 1000 m over the Genoa Gulf, with concentrations reaching 50 ppbv.

  15. Origin of lipid biomarkers in mud volcanoes from the Alboran Sea, western Mediterranean

    NASA Astrophysics Data System (ADS)

    López-Rodríguez, C.; Stadnitskaia, A.; De Lange, G. J.; Martínez-Ruíz, F.; Comas, M.

    2014-06-01

    Mud volcanoes (MVs) are the most prominent indicators of active methane/hydrocarbon venting at the seafloor on both passive and active continental margins. Their occurrence in the western Mediterranean is patent at the West Alboran Basin, where numerous MVs develop overlaying a major sedimentary depocentre containing overpressured shales. Although some of these MVs have been studied, the detailed biogeochemistry of expelled mud so far has not been examined in detail. This work provides the first results on the composition and origin of organic matter, anaerobic oxidation of methane (AOM) processes and general characteristics on MV dynamics using lipid biomarkers as the main tool. Lipid biomarker analysis was performed on MV expelled material (mud breccias) and interbedded hemipelagic sediments from Perejil, Kalinin and Schneider's Heart MVs located in the northwest margin of the Alboran Sea. The n alkane distributions and n alkane-derived indices (CPI and ACL), in combination with the epimerization degree of hopanes (22S/(22S+22R)) indicate that all studied mud breccia have a similar biomarker composition consisting of mainly thermally immature organic matter with an admixture of petroleum-derived compounds. This concordant composition indicates that common source strata must feed all three studied MVs. The past or present AOM activity was established using lipid biomarkers specific for anaerobic methanotrophic archaea (irregular isoprenoids and dialkyl glycerol diethers) and the depleted carbon isotope composition (δ13C) of crocetane/phytane. The presence of these lipid biomarkers, together with the low amounts of detected glycerol dialkyl glycerol tetraethers, is consistent with the dominance of anaerobic methanotrophs of the ANME-2 over ANME-1, at least in mud breccia from Perejil MVs. In contrast, the scarce presence or lack of these AOM-related lipid biomarkers in sediments from Kalinin and Schneider's Heart MVs, suggests that no recent active methane seepage

  16. Comparing the Gibraltar and Calabrian subduction zones (central western Mediterranean) based on seismic tomography

    NASA Astrophysics Data System (ADS)

    Argnani, Andrea; Battista Cimini, Giovanni; Frugoni, Francesco; Monna, Stephen; Montuori, Caterina

    2016-04-01

    The Central Western Mediterranean (CWM) was shaped by a complex tectonic and geodynamic evolution. Deep seismicity and tomographic studies point to the existence, under the Alboran and Tyrrhenian Seas, of lithospheric slabs extending down to the bottom of the mantle transition zone, at 660 km depth. Two narrow arcs correspond to the two slabs, the Gibraltar and Calabrian Arcs (e.g., Monna et al., 2013; Montuori et al., 2007). Similarities in the tectonic and mantle structure of the two areas have been explained by a common subduction and roll-back mechanism for the opening of the CWM, in which the two arcs are symmetrical end products. In spite of this unifying model, a wide amount of literature from different disciplines shows that many aspects of the two areas are still controversial. We present a new 3-D tomographic model at mantle scale for the Calabrian Arc and compare it with a recently published 3-D tomographic model for the Gibraltar Arc by Monna et al (2013). The two models are based on non-linear inversion of teleseismic phase arrivals, and have scale and parametrization that allow for a direct comparison. Unlike previous studies the tomographic models here presented include Ocean Bottom Seismometer broadband data, which improved the resolution of the mantle structures in the marine areas surrounding the arcs. We focus on key features of the two models that constrain reconstructions of the geodynamic evolution of the CWM (e.g., Monna et al., 2015). At Tortonian time the opening of the Tyrrhenian basin was in its initial stage, and the Calabrian arc formed subsequently; on the contrary, the Gibraltar arc was almost completely defined. We hypothesize that the complexity of the continental margin approaching the subduction zone played a key role during the final stages of the arc formation. References Monna, S., G. B. Cimini, C. Montuori, L. Matias, W. H. Geissler, and P. Favali (2013), New insights from seismic tomography on the complex geodynamic evolution

  17. Isotopic composition of carbon and nitrogen of suprabenthic fauna in the NW Balearic Islands (western Mediterranean)

    NASA Astrophysics Data System (ADS)

    Madurell, T.; Fanelli, E.; Cartes, J. E.

    Stable isotope (δ 13C and δ 15N) analyses were performed on suprabenthic fauna collected in the western Mediterranean (NW Balearic Islands), at depths ranging between 350 and 780 m. Samples were collected seasonally at bi-monthly intervals during six cruises performed between August 2003 and June 2004, using a Macer-GIROQ suprabenthic sledge (0.5 mm mesh size). Twenty-four separate species (5 mysids, 12 amphipods, 2 cumaceans, 2 isopods, 1 euphausiid, 1 decapod and 1 fish) and bulk copepods were analyzed on a seasonal basis for stable carbon and nitrogen isotopes. Stable nitrogen isotope ratios (δ 15N) ranged from 2.3‰ (the amphipod Lepechinella manco in September 2003) to 13.0‰ (the amphipod Rhachotropis caeca in August 2003). δ 13C values ranged from - 24.2 (the cumacean Campylaspis sulcata in June 2004) to - 16.1 (the amphipod Bruzelia typica in November 2006). Both δ 13C and δ 15N values suggest that there are three trophic levels within the suprabenthic community. However, considering the bathymetric range of the species, the results suggest that the deepest assemblage supported only two trophic levels. The stable isotope ratios of suprabenthic fauna displayed a continuum of values and confirmed a wide spectrum of feeding types (from filter-feeders to predators). In general, and in spite of the poor knowledge about diets available for most suprabenthic species, higher δ 15N were found for carnivorous amphipods (e.g. Rhachotropis spp., Nicippe tumida) consuming copepods. Low overlap for δ 13C and δ 15N values was observed, though δ 15N values where less variable than δ 13C, which suggests high resource partitioning in this assemblage. Seasonal variations in isotopic composition for both δ 13C and δ 15N were low (less than 1‰ and 3‰, respectively) and variable depending on species. Low correlations between δ 13C and δ 15N of suprabenthic fauna were found for all periods studied, though increasing from February 2004 to June 2004 (after the

  18. Metazoan parasites in the head region of the bullet tuna Auxis rochei (Osteichthyes: Scombridae) from the western Mediterranean Sea.

    PubMed

    Mele, S; Saber, S; Gómez-Vives, M J; Garippa, G; Alemany, F; Macías, D; Merella, P

    2015-11-01

    The head region of 72 bullet tuna Auxis rochei from the western Mediterranean Sea (south-east Spain and the Strait of Gibraltar) was examined for parasites. Seven metazoan species were found in the fish from south-east Spain: three monogeneans, two trematodes and two copepods, whereas only three species were isolated in the fish from the Strait of Gibraltar. A comparison of the levels of infection of the parasites according to fish size in south-east Spain showed that the prevalence of Didymozoon auxis and the mean abundance of Allopseudaxine macrova were higher in the larger hosts (range of fork length = 38-44 cm) than in the smaller ones (33-37 cm). A comparison of the parasite infections according to geographical region showed that the mean abundances of Nematobothriinae gen. sp. and Caligus bonito were higher in fish from south-east Spain than in those from the Strait of Gibraltar. A comparison of the parasite fauna of A. rochei from the Mediterranean Sea with the published data on Auxis spp. from the Atlantic, Indian and Pacific Oceans revealed the closest similarity between the Mediterranean A. rochei and the Atlantic A. thazard.

  19. The western Mediterranean basin as an aged aerosols reservoir. Insights from an old-fashioned but efficient radiotracer

    NASA Astrophysics Data System (ADS)

    Brattich, E.; Hernández-Ceballos, M. A.; Orza, J. A. G.; Bolívar, J. P.; Tositti, L.

    2016-09-01

    The long-term contemporary 210Pb time series acquired during the period 2004-2011 at two distant sites of different altitude in the Mediterranean basin, El Arenosillo (40 m a.s.l. in southwestern Spain) and Mt. Cimone (2165 m a.s.l. in northern Italy), are analyzed and compared. Besides being considered a tracer of continental air masses, 210Pb radionuclide is also a proxy of fine stable aerosol. For this reason, the measurements of PM10 mass concentrations collected at the same time and the corresponding 210Pb/PM10 ratio at the two sites are considered to gain better insights into the origin and size of the particles. Three statistical trajectory methods are applied to identify and characterize the 210Pb source regions at the two sites. The three methods yield similar outcomes in the source identification, which strengthens the robustness of our results. In addition to the importance of the transport from areas of continental Europe, this study highlights the relevant role of the Mediterranean Sea as a major 210Pb reservoir layer associated to the aged air masses that accumulate in the western Mediterranean basin. The analysis of the sources points out the significant influence of northern Africa to 210Pb increases at both sites as well, even though the most intensive episodes are not of Saharan origin.

  20. Geochemical signal in drip waters and carbonates from three year monitoring of Drac Cave in Mallorca (Western Mediterranean)

    NASA Astrophysics Data System (ADS)

    Cacho, Isabel; Cisneros, Mercé; Torner, Judit; Moreno, Ana; Stoll, Heather; Bladé, Ileana; Fornos, Joan

    2016-04-01

    In order to establish the potential connection between climatic conditions over Mallorca and the chemistry of speleothem growths, a still ongoing monitoring exercise is in development in Drac Cave in Mallorca (Spain) starting from April 2013. This location in the Western Mediterranean was selected to represent Mediterranean semi-arid climatic conditions within a wider monitoring plan covering a transect across the northern part of the Iberian Peninsula, from the Catabric realm, across the Pyrenees and Iberian ranges until the Mediterranean, within the framework of the OPERA research project. Drip waters have been recovered at weakly resolution and carbonate precipitates represent seasonal periods. This monitoring is complemented with drip water and carbonate collection at seasonal scale in another cave close to Drac Cave. This second cave was selected in order to represent comparable climatic conditions but far of any human land-intervention since the Drac cave is partially located under an urban developed area, although drip water and carbonate collection is performed in a location bellow autochthonous forest. First results show that drip flow has a rather constant rate along the year even though the large contrast on rain availability. In contrast, chemical signal of the drip waters shows a rapid response (few days) to changes in rain patterns but of relatively small magnitude. Isotopes in the carbonate precipitates present a seasonal signal and trend that reflect changes in the drip water composition. This data set, although preliminary, will be discussed in the context of the changing meteorological conditions of the last three years.

  1. PRKCZ methylation is associated with sunlight exposure in a North American but not a Mediterranean population.

    PubMed

    Aslibekyan, Stella; Dashti, Hassan S; Tanaka, Toshiko; Sha, Jin; Ferrucci, Luigi; Zhi, Degui; Bandinelli, Stefania; Borecki, Ingrid B; Absher, Devin M; Arnett, Donna K; Ordovas, Jose M

    2014-11-01

    Sunlight exposure has been shown to alter DNA methylation patterns across several human cell-types, including T-lymphocytes. Since epigenetic changes establish gene expression profiles, changes in DNA methylation induced by sunlight exposure warrant investigation. The purpose of this study was to assess the effects of sunlight exposure on CD4+ T-cell methylation patterns on an epigenome-wide scale in a North American population of European origin (n=991). In addition, we investigated the genetic contribution to epigenetic variation (methylQTL). We used linear regression to test the associations between methylation scores at 461,281 cytosine-phosphate-guanine (CpG) sites and sunlight exposure, followed by a genome-wide association analysis (methylQTL) to test for associations between methylation at the top CpG locus and common genetic variants, assuming an additive genetic model. We observed an epigenome-wide significant association between sunlight exposure and methylation status at cg26930596 (p=9.2×10(-8)), a CpG site located in protein kinase C zeta (PRKCZ), a gene previously shown to be entrained by light. MethylQTL analysis resulted in significant associations between cg26930596 and two intergenic single nucleotide polymorphisms on chromosome 3, rs4574216 (p=1.5×10(-10)) and rs4405858 (p=1.9×10(-9)). These common genetic variants reside downstream of WWTR1, a transcriptional co-activator of PRKCZ. Associations observed in the North American population, however, did not replicate in an independent Mediterranean cohort. Our preliminary results support the role of sunlight exposure in epigenetic processes, and lay the groundwork for future studies of the molecular link between sunlight and physiologic processes such as tumorigenesis and metabolism.

  2. PRKCZ methylation is associated with sunlight exposure in a North American but not a Mediterranean population

    PubMed Central

    Aslibekyan, Stella; Dashti, Hassan S.; Tanaka, Toshiko; Sha, Jin; Ferrucci, Luigi; Zhi, Degui; Bandinelli, Stefania; Borecki, Ingrid B.; Absher, Devin M.; Arnett, Donna K.; Ordovas, Jose M.

    2015-01-01

    Sunlight exposure has been shown to alter DNA methylation patterns across several human cell-types, including T-lymphocytes. Since epigenetic changes establish gene expression profiles, changes in DNA methylation induced by sunlight exposure warrant investigation. The purpose of this study was to assess the effects of sunlight exposure on CD4+ T-cell methylation patterns on an epigenome-wide scale in a North American population of European origin (n = 991). In addition, we investigated the genetic contribution to epigenetic variation (methylQTL). We used linear regression to test the associations between methylation scores at 461 281 cytosine-phosphate-guanine (CpG) sites and sunlight exposure, followed by a genome-wide association analysis (methylQTL) to test for associations between methylation at the top CpG locus and common genetic variants, assuming an additive genetic model. We observed an epigenome-wide significant association between sunlight exposure and methylation status at cg26930596 (p = 9.2 × 10−8), a CpG site located in protein kinase C zeta (PRKCZ), a gene previously shown to be entrained by light. MethylQTL analysis resulted in significant associations between cg26930596 and two intergenic single nucleotide polymorphisms on chromosome 3, rs4574216 (p = 1.5 × 10−10) and rs4405858 (p = 1.9 × 10−9). These common genetic variants reside downstream of WWTR1, a transcriptional co-activator of PRKCZ. Associations observed in the North American population, however, did not replicate in an independent Mediterranean cohort. Our preliminary results support the role of sunlight exposure in epigenetic processes, and lay the groundwork for future studies of the molecular link between sunlight and physiologic processes such as tumorigenesis and metabolism. PMID:25075435

  3. When did Mediterranean Outflow Water begin to circulate into the North Atlantic?

    NASA Astrophysics Data System (ADS)

    Hernández Molina, Francisco Javier; Stow, Dorrik A. V.; Zarikian, Carlos

    2014-05-01

    The southwestern Iberian margin records critical evidence of Mediterranean Outflow Water (MOW) following its exit through the Strait of Gibraltar. Data collected during Integrated Ocean Drilling Program (IODP) Expedition 339 provide new constraints on MOW circulation patterns from Pliocene to present time, which indicate an alternative sequence of events in the establishment of global ocean circulation patterns. Following the opening of the Strait of Gibraltar (5.46 Ma), a limited volume of weak MOW entered the Atlantic at about 4.5- 4.2 Ma. Two depositional hiatuses evident at 3.2-3.0 Ma and 2.4-2.1 Ma indicate that significant MOW circulation into the North Atlantic did not occur until the Late Pliocene and early Pleistocene. These hiatuses accompany other changes in sedimentary processes. A younger event at 0.9-0.7 Ma suggests additional Pleistocene phase of MOW intensification. These events are coeval with global changes in deep-water sedimentation associated with shifts in global thermohaline circulation (THC). The events evident from sediment cores and seismic records interpreted here suggest that MOW provided an important, additional component of warm, saline waters to northern latitudes, thus enhancing Atlantic Meridional Overturning Circulation (AMOC). Similar changes have been globally described, suggesting a link between climatic shifts, THC and plate tectonic events.

  4. Atmospheric wet deposition of soluble macro-nutrients in the Cilician Basin, north-eastern Mediterranean sea.

    PubMed

    Ozsoy, Türkan

    2003-12-01

    In order to estimate wet deposition atmospheric fluxes of macro-nutrients into the eastern Mediterranean coastal waters, soluble inorganic phosphate (PO4(3-)), nitrate (NO3-) and nitrite (NO2-) concentrations in precipitation (from February 1996 to June 1997) have been measured at a coastal sampling site, Erdemli, Turkey. Water-soluble inorganic PO4(3)-P, a reactive, bioavailable, limiting macro-nutrient in the oligotrophic waters of the eastern Mediterranean was studied with respect to its contribution to biological productivity. Reactive PO4(3-)-P and NO2(-) + NO3(-)-N concentrations were found to be highly variable in rainwater samples. One of the aims of the study was to determine the contribution of dust transport to the soluble macro-nutrient budget of the eastern Mediterranean. No differences were found between the mean reactive P and NO(2-) + NO3(-)-N concentrations of "red rain" and normal rain events. Most likely as a result of low solubility of crustal phosphorus, dust episodes were not found to be important sources of reactive P, in terms of wet deposition. The annual wet deposition fluxes of reactive PO4(3-)-P and NO2(-) + NO3(-)-N into the Cilician Basin were respectively estimated to be 0.010 g P m(-2) per year and 0.23 g N m(-2) per year, which are comparable to the fluxes from land-based sources in the north-eastern Mediterranean. The incorporation of water soluble bioavailable PO4(3-)-P and NO2(-) + NO3(-)-N delivered via atmospheric wet deposition could be responsible for approximately 3.3% (0.40 g C m(-2) per year) and 11.0% (1.31 g C m(-2) per year) respectively, of the mean annual new production in the north-eastern Mediterranean.

  5. Gulf of California analogue for origin of Late Paleozoic ocean basins adjacent to western North America

    SciTech Connect

    Murchey, B.L. )

    1993-04-01

    Ocean crust accreted to the western margin of North America following the Late Devonian to earliest Missippian Antler orogeny is not older than Devonian. Therefore, ocean crust all along the margin of western North America may have been very young following the Antler event. This situation can be compared to the present-day margin of North America which lies adjacent to young ocean crust as a result of the subduction of the Farallon plate and arrival of the East Pacific spreading ridge. Syn- and post-Antler rifting that occurred along the North American margin may well be analogous to the formation of the Gulf of California by the propagation of the East Pacific spreading ridge. Black-arc rifting associated with the subduction of very old ocean crust seems a less likely mechanism for the early stages of ocean basin formation along the late Paleozoic margin of western North America because of the apparent absence of old ocean crust to the west of the arc terranes. The eastern Pacific basins were as long-lived as any truly oceanic basins and may have constituted, by the earliest Permian, a single wedge-shaped basin separated from the western Pacific by rifted fragments of North American arc-terranes. In the Permian, the rifted arcs were once again sites of active magmatism and the eastern Pacific basins began to close, from south (Golconda terrane) to north. Final closure of the northernmost eastern Pacific basin (Angayucham in Alaska) did not occur until the Jurassic.

  6. Experimental infection of house sparrows (Passer domesticus) with West Nile virus isolates of Euro-Mediterranean and North American origins

    PubMed Central

    2014-01-01

    West Nile virus (WNV) is a zoonotic arboviral pathogen transmitted by mosquitoes in a cycle involving wild birds as reservoir hosts. The virus has recently emerged in North America and re-emerged in Europe. North American WNV outbreaks are often accompanied by high mortality in wild birds, a feature that is uncommon in Europe. The reason for this difference is unknown, but the intrinsic virulence of the viruses circulating in each continent and/or the susceptibility to the disease of Palearctic as opposed to Nearctic wild bird species could play a role. To assess this question, experimental inoculations with four lineage 1 WNV strains, three from southern Europe (Italy/2008, Italy/2009 and Spain/2007) and one from North America (NY99) were performed on house sparrows (Passer domesticus), a wild passerine common in both continents. Non-significant differences which ranged from 0% to 25% were observed in mortality for the different WNV strains. Viremias lasted from 1 to 5–6 days post-inoculation (dpi) in all cases; individuals inoculated with NY99 had significantly higher titres than those inoculated with any of the Euro-Mediterranean strains. Remarkably, host competence was found to be higher for NY99 than for the other strains. Consequently, albeit being pathogenic for house sparrows, some Euro-Mediterranean strains had reduced capacity for replication in -and transmission from- this host, as compared to the NY99 strain. If applicable also to other wild bird host species, this relatively reduced transmission capacity of the Euro-Mediterranean strains could explain the lower incidence of this disease in wild birds in the Euro-Mediterranean area. PMID:24641615

  7. Abundance and distribution of Tursiops truncatus in the Western Mediterranean Sea: an assessment towards the Marine Strategy Framework Directive requirements.

    PubMed

    Lauriano, Giancarlo; Pierantonio, Nino; Donovan, Greg; Panigada, Simone

    2014-09-01

    The Mediterranean Sea common bottlenose dolphin population has been assessed as Vulnerable according to the IUCN Red List Criteria. The species is also included in several International Agreements, European Union Regulations and Directives. Amongst them, a strict protection and identification of special conservation areas are requested by the EU Habitats Directive. Despite direct takes, by-catch, chemical and acoustic pollution, and prey depletion, general habitat degradation and fragmentation have been indicated as detrimental for the species, the degree to which these threats pose population risk is still largely unknown. At present it is thus not possible to depict the actual status of the population and to assess prospective trends. To address this gap in the current knowledge, line transect distance sampling aerial surveys were conducted in a wide portion of the Western Mediterranean Sea between the summer of 2010 and winter 2011. A total of 165 parallel transects equally spaced at 15 km were designed providing homogeneous coverage probability. Overall, 21,090 km were flown on effort and 16 bottlenose dolphin sightings were recorded and used for the analysis. The surface abundance and density estimates resulted in 1676 animals (CV = 38.25; 95% CI = 804-3492) with a density of 0.005 (CV = 38.25%). These results represent the first ever estimates for the common bottlenose dolphin over a wide portion of the Western Mediterranean Sea Subregion, with the potential to be useful baseline data to inform conservation. Specifically, they could be used as indicators under the Marine Strategy Framework Directive requirements, in conjunction with other study methods. PMID:24784442

  8. Dolomitizing seas in evaporitic basins: A model for pervasive dolomitization of upper Miocene reefal carbonates in the western Mediterranean

    SciTech Connect

    Oswald, E.J.; Schoonen, M.A.A.; Meyers, W.J. )

    1991-03-01

    Petrographic, stratigraphic, and stable-isotopic data from a dolomitized upper Miocene reef complex on Mallorca, Spain, coupled with the presence of extensive Messinian subtidal evaporite deposits throughout the western Mediterranean suggests that Messinian evaporitic brines were responsible for dolomitization. Thermodynamic reaction-path modeling was undertaken to more rigorously and quantitatively demonstrate the dolomitizing potential of this evaporitic system. These calculations provide maximum amounts of dissolution or precipitation (moles/L) to maintain a specified fluid-rock equilibrium. Significant amounts of dolomite can be created when brines ar concentrated by evaporation prior to reaction with calcite. Heavy stable isotopes of Mallorcan dolomites are consistent with an evaporitic origin; however, lighter stable isotopes do not preclude this model. Calculations show that mixing evolved brines with unaltered seawater or continental waters produces a suite of fluids with much greater dolomitization potential than seawater and oxygen-isotope signatures approaching those of seawater. This evaporitic-basin model serves as one hypothesis for the many dolomitized upper Miocene reef complexes around the western Mediterranean, and may be applicable to many older Phanerozoic carbonates associated with basinal evaporites.

  9. Estimates of volume, heat and freshwater budgets for the Arctic Mediterranean and North Atlantic in relation to the main physical processes: Insight from the EU-NACLIM observations

    NASA Astrophysics Data System (ADS)

    Rudels, Bert; Hansen, Bogi; Karstensen, Johannes; McCarthy, Gerard; Quadfasel, Detlef

    2016-04-01

    The EU NACLIM (North Atlantic Climate) project aims to understand the forcing of the North Atlantic circulation and its importance for the climate of northwestern Europe. NACLIM comprises extensive modelling studies of the atmosphere, ocean and climate, but here mainly the oceanographic observations are presented. The core observation areas are the North Atlantic Subpolar Gyre and the Greenland-Scotland Ridge, separating the North Atlantic from the Arctic Mediterranean Sea. These are the areas, where the waters of the lower limb of the Meridional Overturning Circulation (MOC) are formed and sink into the deep North Atlantic to return southward, mainly in the Deep Western Boundary Current (DWBC). The exchanges across the Greenland-Scotland Ridge, both the northward flowing Atlantic and the returning dense waters, have been monitored over decades, as have the circulation in the Subpolar gyre and the convection and mode water formation in the Labrador Sea. These studies are extended southward to the RAPID array located in the Subtropical gyre at 26oN to capture the MOC further south, and northward into the Arctic Mediterranean Sea and the formation area of the densest water in the DWBC. In the Subtropical gyre the ocean circulation is mainly forced by the wind, while in the Subpolar gyre the atmospheric influence, in addition to wind forcing, also has a large thermodynamic component, changing the characteristics of the water masses and the density structure of the gyre. The importance of cooling and freshwater input increases in the Arctic Mediterranean Sea. Variability and a recent declining trend of the MOC strength have been observed in the Subtropical gyre at the RAPID array. By contrast, both the northward flow across the Greenland-Scotland Ridge and the overflows have remained steady during the observation periods. An increased atmospheric freshwater flux does not appear to affect the dense water formation in the Arctic Mediterranean, mainly because the low

  10. A large scale survey of trace metal levels in coastal waters of the Western Mediterranean basin using caged mussels (Mytilus galloprovincialis).

    PubMed

    Benedicto, José; Andral, Bruno; Martínez-Gómez, Concepción; Guitart, Carlos; Deudero, Salud; Cento, Alessandro; Scarpato, Alfonso; Caixach, Josep; Benbrahim, Samir; Chouba, Lassaad; Boulahdid, Mostefa; Galgani, François

    2011-05-01

    A large scale study of trace metal contamination (Hg, Cd, Pb and Ni) by means of caged mussels Mytilus galloprovincialis was undertaken along the coastal waters of the Western Mediterranean Sea within the context of the MYTILOS project. Individual mussels from an homogeneous population (shell size 50 ± 5 mm) obtained from an aquaculture farm were consecutively caged and deployed at 123 sites located in the Alborán, North-Western, South-Western and Tyrrhenian sub-basins for 12 weeks (April-July) in 2004, 2005 and 2006. After cage recoveries, both the metal content in the whole mussel tissue and the allometric parameters were measured. Statistical analysis of the datasets showed significant differences in concentrations between sub-basins for some metals and mussel condition index (CI). Linear regression models coupled to the CI were revisited for the data adjustment of certain trace metals (Hg, Cd and Ni), and four level categories were statistically derived to facilitate interregional comparison. Seawater masses surrounding coastal areas impacted by run-off from land mineralised coasts and industrial activities displayed the highest concentration ranges (Hg: 0.15-0.31 mg kg(-1) dw; Cd: 1.97-2.11; Ni: 2.18-3.20 and Pb: 3.1-3.8), although the levels obtained in most of the sites fitted within moderate or low categories, and they could be considered as baseline concentrations. However, few sites considered little-influenced by human activities, at present, showed high concentrations of Cd, Ni and Pb, which constitute new areas of concern. Overall, the use of active biomonitoring (ABM) approach allowed to investigate trace metal contamination in order to support policy makers in establishing regional strategies (particularly, with regard to the European Marine Strategy Directive). PMID:21384032

  11. Climate changes in south western Iberia and Mediterranean Outflow variations during two contrasting cycles of the last 1 Myrs: MIS 31-MIS 30 and MIS 12-MIS 11

    NASA Astrophysics Data System (ADS)

    Sánchez Goñi, M. F.; Llave, E.; Oliveira, D.; Naughton, F.; Desprat, S.; Ducassou, E.; Hodell, D. A.; Hernández-Molina, F. J.

    2016-01-01

    Grain size analysis and physical properties of Sites U1388, U1389 and U1390 collected in the Contourite Depositional System of the Gulf of Cádiz during the Integrated Ocean Drilling Program (IODP) Expedition 339 "Mediterranean Outflow" reveal relative changes in bottom current strength, a tracer of the dynamics of the Mediterranean Outflow Water (MOW), before and after the Middle Pleistocene Transition (MPT). The comparison of MOW behavior with climate changes identified by the pollen analysis and δ18O benthic foraminifera measurements of Site U1385, the Shackleton Site, collected in the south western Iberian margin shows that the interval MIS 31-MIS 30, ~ 1.1-1.05 million years ago (Ma), before the MPT, was marked by wetter climate and weaker bottom current than the interval MIS 12-MIS 11 (0.47-0.39 Ma), after the MPT. Similarly, the increase in fine particles from these glacials to interglacials and in coarse fraction from interglacials to glacials was coeval with forest and semi-desert expansions, respectively, indicating the lowering/enhancement of MOW strength during periods of regional increase/decrease of moisture. While these findings may not necessarily apply to all glacial/interglacial cycles, they nonetheless serve as excellent supporting examples of the hypothesis that aridification can serve as a good tracer for MOW intensity. The strongest regional aridity during MIS 12 coincides with a remarkable increase of coarse grain size deposition and distribution that we interpret as a maximum in MOW strength. This MOW intensification may have pre-conditioned the North Atlantic by increasing salinity, thereby triggering the strong resumption of the Meridional Overturning Circulation that could contribute to the great warmth that characterizes the MIS 11c super-interglacial.

  12. The Contribution of the Topo-Iberia Project to the Knowledge of the Western Mediterranean Geodynamics.

    NASA Astrophysics Data System (ADS)

    Diaz Cusi, J.

    2012-12-01

    The large scale research program Topo-Iberia aims to unravel the complex structure and mantle processes in the area of interaction between the African and European continental plates in the western Mediterranean. The project, funded by the Spanish Ministry of Science and Education, started in 2007 and will be active till Fall 2013. Topo-Iberia has gathered expertise of different fields of the Earth Sciences. One of the key assets of the project involves the deploying of a technological observatory platform, IberArray, with unprecedented resolution and coverage. This platform is currently building up a comprehensive, multidisciplinary data set, stored by the SIGEOF database, which includes seismological, GPS and magnetotelluric data. Using also other analytical methodologies included in the Topo-Iberia program (potential fields, quantitative analysis of the topography, dating methods) the final scope of the project is to study the relationship between superficial and deep-rooted processes. Topo-Iberia has also benefited from the interaction with other projects investigating the same area, as the American program PICASSO, the French Pyrope or the Portuguese WILAS. This interaction includes sharing the available data to better assess the key geological questions. This contribution will present the current state of the most significant scientific results which are arising from the data acquired using the Iberarray platform. -. SKS splitting analysis has provided a spectacular image of the anisotropic pattern over the area, including a clear rotation of the fast velocity direction along the Gibraltar Arc. -. Receiver functions have revealed the crustal thickness variations beneath the Rif and southern Iberia, including a crustal root beneath the Rif not clearly documented previously. The 410-km and 660-km upper mantle discontinuities have been investigated using novel cross-correlation/stacking techniques. -. Surface wave tomography using both earthquakes and ambient

  13. Soil and plant contamination by lead mining in Bellmunt (Western Mediterranean Area)

    NASA Astrophysics Data System (ADS)

    Bech, Jaume; Duran, Paola; Barceló, Juan; Roca, Núria; Tume, Pedro; Poschenrieder, Charlotte

    2010-05-01

    Galena has been mined in Bellmunt (Priorat, Western Mediterranean Area) since ancient times until 1972. While sediment pollution originated by the mining activity in the Ebro river passing the region has been investigated (Ferré, 2007), the local impact on soils and plants has received little attention. Here we report the first results on the concentrations of major metal contaminants and antimony in soils and representative plants from 5 selected sites with different pollutant burdens around the mining area. Both total (HNO3, HF, HClO4 digest) and extractable (EDTA) soil concentrations were studied. The range of total and extractable soil values in mgkg-1 is as follows: Sb 9.7-31 and 2.4-7.2; Cu: 89-823 and 20-62; Pb: 19-39 and 18-33; Zn: 318-989 and 79-287 mg•kg-1, respectively). Soils had alkaline pH (7.7-8.2), organic matter contents ranging from 0.8 to 2.4%, and a sandy-loam or a loamy-sand texture. All analysed plant species showed enhanced root and shoot concentrations of Pb, Cu, Zn and Sb when growing on the more polluted soils, and all but one restricted the translocation of metals from roots to shoots exhibiting shoot/root concentration ratios lower than unity. A notably exception was Moricandia moricandioides. This species of the Brassicaceae family exhibited higher Zn concentrations in the shoots than in the roots at all sampling sites yielding shoot/root concentration ratios up to 5.5. This metal accumulation pattern was only observed for Zn and not for other analysed metal contaminants. The concentrations of other, poorly mobile metals, like Pb or Cu were always higher in roots than in shoots (e.g. Pb shoot/root ratios ranged from 0.12 to 0.41). Taking into account the high Pb burden of the soil samples and these low shoot/root Pb ratios, it can be excluded that the particular Zn accumulation pattern of Moricandia moricandioides was biased by soil contamination of shoot samples. To the best of our knowledge, this is the first report of a Zn

  14. Recent Inversion, Seismic Potential, and Neogene Kinematics of the Algerian Margin (Western Mediterranean) from Offshore Studies

    NASA Astrophysics Data System (ADS)

    Deverchere, J.; Yelles, K.; Bracene, R.; Mercier de Lepinay, B. F.; Cattaneo, A.; Medaouri, M.; Gaullier, V.; Babonneau, N.; Ratzov, G.; Boudiaf, A.; Graindorge, D.; Kherroubi, A.; Strzerzynski, P. H.; Authemayou, C.; Djellit, H.; Heddar, A.; Maradja'03; Maradja-Samra'05 Scientific Teams

    2011-12-01

    The reasons to study the Algerian margin (Western Mediterranean) are at least threefold: (1) the seismic hazard offshore is obviously present but unconstrained, (2) the way the opening of the Algerian basin occurred is highly debated, and (3) this margin represents one of the rare examples on Earth of an ongoing subduction inception. We present an overview of recent findings on the tectonic evolution of this margin, where most of the plate convergence between Africa and Europe is taken up today, mostly from cruises MARADJA and MARADJA2/SAMRA led by joint Algerian and French teams. Large, overlapping active thrust faults and folds apparently dominate the seismotectonic pattern from the Atlas domain on land to the foot of the margin offshore, with a clear segmentation. Strain is distributed across the whole area, with a significant part of the relative plate convergence taken up offshore. Fault activity offshore is tenuous and most often indirect (Plio-Quaternary growth strata, folds, uplifted basins, scars and slope breaks). Along the eastern margin, faults form stepwise, en-échelon systems on the slope and in the deep basin. Some thrusts identified turn to fault-propagation folds at the sub-surface. Thrusts interact with the sediment flux, Messinian salt and seafloor currents, forming complex structures at deep-sea fans and scarps or scars on the main slope breaks. The 2003 Mw 6.9 Boumerdes rupture is correlated segmented cumulative scarps on the slope and at the foot of the margin. Using various VHR seismic reflection and coring analyses, we show that the record of turbidite deposition since ca. 10.000 yrs can be identified and correlated over long distances within or across large segments of the margin affected by the 1954, 1980 and 2003 events. The consequences in term of earthquake size and recovery of their recurrences (identification of paleo-events) are explored and discussed. Although we cannot associate the triggering of large turbidity currents to a

  15. Circulation of a Meaban-Like Virus in Yellow-Legged Gulls and Seabird Ticks in the Western Mediterranean Basin

    PubMed Central

    Cerdà-Cuéllar, Marta; Lecollinet, Sylvie; Pearce-Duvet, Jessica; Busquets, Núria; García-Bocanegra, Ignacio; Pagès, Nonito; Vittecoq, Marion; Hammouda, Abdessalem; Samraoui, Boudjéma; Garnier, Romain; Ramos, Raül; Selmi, Slaheddine; González-Solís, Jacob; Jourdain, Elsa; Boulinier, Thierry

    2014-01-01

    In recent years, a number of zoonotic flaviviruses have emerged worldwide, and wild birds serve as their major reservoirs. Epidemiological surveys of bird populations at various geographical scales can clarify key aspects of the eco-epidemiology of these viruses. In this study, we aimed at exploring the presence of flaviviruses in the western Mediterranean by sampling breeding populations of the yellow-legged gull (Larus michahellis), a widely distributed, anthropophilic, and abundant seabird species. For 3 years, we sampled eggs from 19 breeding colonies in Spain, France, Algeria, and Tunisia. First, ELISAs were used to determine if the eggs contained antibodies against flaviviruses. Second, neutralization assays were used to identify the specific flaviviruses present. Finally, for colonies in which ELISA-positive eggs had been found, chick serum samples and potential vectors, culicid mosquitoes and soft ticks (Ornithodoros maritimus), were collected and analyzed using serology and PCR, respectively. The prevalence of flavivirus-specific antibodies in eggs was highly spatially heterogeneous. In northeastern Spain, on the Medes Islands and in the nearby village of L'Escala, 56% of eggs had antibodies against the flavivirus envelope protein, but were negative for neutralizing antibodies against three common flaviviruses: West Nile, Usutu, and tick-borne encephalitis viruses. Furthermore, little evidence of past flavivirus exposure was obtained for the other colonies. A subset of the Ornithodoros ticks from Medes screened for flaviviral RNA tested positive for a virus whose NS5 gene was 95% similar to that of Meaban virus, a flavivirus previously isolated from ticks of Larus argentatus in western France. All ELISA-positive samples subsequently tested positive for Meaban virus neutralizing antibodies. This study shows that gulls in the western Mediterranean Basin are exposed to a tick-borne Meaban-like virus, which underscores the need of exploring the spatial and

  16. The multidecadal component of the Mediterranean summer variability

    NASA Astrophysics Data System (ADS)

    OrtizBevia, M. J.; RuizdeElvira, A.; Alvarez-Garcia, F. J.; Tasambay-Salazar, M.

    2016-09-01

    This study targets the low frequency components of the anomalous Mediterranean summer climatic variability. This last is characterised here by two indexes obtained from a statistical analysis of Mediterranean sea surface temperature anomalies. The evolution of the first of them, the Western Mediterranean Index, is dominated by a multidecadal timescale. This Index has a strong statistical impact on the summer air temperature anomalies in the European region. In the other index, the Mediterranean Dipole Index, the decadal timescale plays a major part. This last Index is linked to anomalous summer precipitations in some central European regions. A statistical methodology is used in order to identify some feedback relationships between the two Mediterranean indexes and other climate indexes which characterise some global or regional variability. In the case of the Western Mediterranean Index, the analysis reveals significant feedback relationships with two of these indexes. The selected predictors are introduced as variables in a statistical feedback model. The cross-skills scored in a cross-validation hindcast experiment reveals an important potential predictability. In this way, the multidecadal Mediterranean summer sea surface temperature variability appears as the result of two forcings, one related to the north-western Atlantic processes and the other connected to the north tropical Atlantic, and to a weak feedback onto the Atlantic. In the case of the Mediterranean Dipole Mode Index we have not found enough predictive potential in the feedback relationships identified.

  17. Relationships between El Niño-Southern Oscillation and nitrogen concentrations in a Western Mediterranean river

    NASA Astrophysics Data System (ADS)

    Sigro, J.; Vegas-Vilarrúbia, T.; Giralt, S.; Brunet, M.

    2010-05-01

    El Niño-Southern Oscillation (ENSO) is the dominating mode of interannual climate variability at global scale (Brönnimann, 2007). ENSO extreme negative and positive phases can significantly influence on climatic conditions in Europe, affecting precipitation mainly in spring and autumn (Mariotti et al., 2002; Moron and Ward 1998), but also during winter (Brönnimann et al., 2007; Pozo-Vázquez et al., 2005). Over the Iberian Peninsula (IP), ENSO teleconnections can modulate the frequency and intensity of precipitation (Brunet and López, 1991; Rodó et al., 1997; Rodríguez-Puebla et al., 1998), with a time-lag between the ENSO and its effect on precipitation ranging from 3 to 21 months (Rodó et al., 1997). Large areas of the IP are also affected by severe droughts during the final months of La Niña years and the initial months of the following year, while other areas are affected by dry conditions during the first months of El Niño years, as well as during the summers and autumns of the following year (Muñoz-Diaz and Rodrigo, 2005; Vicente-Serrano, 2005). Here we explore the possibility that nitrate concentration in the Llobregat River (North-eastern Spain) is influenced by ENSO events, which are modulating precipitation variability over the Western Mediterranean basin. The Southern Oscillation Index during La Niña years, the self-calibrating Palmer Hydrological Drought Index (van der Schrier et al., 2006; Wells et al., 2004), and nitrate concentrations were significantly correlated on a seasonal basis in the Llobregat River, with both drought and nitrate concentrations increasing during positive ENSO phases. Our hypothesis is that initially unusual within-stream nitrate increases would take place, owing to higher-than-normal evaporation from the river. During drought periods, the hydrological deficit favours nitrate accumulation in the catchment's soils and, thus, a decline in allochthonous inputs to the river water would be expectable. Besides, on the late

  18. Miocene to Pliocene osmium isotopic records of Mediterranean sediments

    NASA Astrophysics Data System (ADS)

    Kuroda, Junichiro; Jiménez-Espejo, Francisco J.; Nozaki, Tatsuo; Gennari, Rocco; Lugli, Stefano; Manzi, Vinicio; Roveri, Marco; Flecker, Rachel; Suzuki, Katsuhiko; Yoshimura, Toshihiro; Sierro, Francisco; Ohkouchi, Naohiko

    2015-04-01

    In the late Miocene the Mediterranean Sea experienced a salinity crisis and thick sequences of evaporites precipitated across the basin. In this study we report Os isotopic records from drilled cores in the Mediterranean; the Balearic Sea, the Tyrrhenian Sea, the Ionian Basin and the Florence Rise. Pliocene sediments at all sites show 187Os/188Os values close to that of the coeval ocean water, indicating that the Mediterranean was connected to the North Atlantic. Evaporitic sediments deposited during the late Miocene however, have 187Os/188Os values lower than coeval ocean water values and samples from the eastern Mediterranean and Ionian basins are particularly low. Os isotopic ratios of the pre-evaporite sediments in the western Mediterranean are almost identical to that of the coeval ocean water. In contrast, equivalent sediments from the Florence Rise have significantly lower 187Os/188Os values. The offset of Mediterranean evaporite 187Os/188Os is attributed to limited exchange with the North Atlantic during the Messinian Salinity Crisis (MSC). The source of unradiogenic Os is likely to be weathering of ultramafic rocks (ophiolites) cropping out in the Mediterranean's drainage basins. The offset in the Os ratio on the Florence Rise is attributed either to limited water exchange between eastern and western Mediterranean, or to local effects associated with exhumation of ophiolites around the eastern Mediterranean Sea.

  19. Pliocene Transgression in the Western Mediterranean Sea: Strontium Isotopes from Cuevas Del Almanzora (Se Spain)

    NASA Astrophysics Data System (ADS)

    Müller, Daniel W.

    1993-02-01

    The deposition of marine sediments in the deep Mediterranean basins following the Messinian salinity crisis ("Zanclean Deluge") began at 4.9 Ma and continued until normal marine conditions prevailed at 4.6 Ma. The Betic Strait of southeast Spain, the Rif Strait of northern Morocco, and the Strait of Gibraltar have been postulated as possible entry ways for the marine waters into the Mediterranean. Two possible explanations have been offered for the timing of the deposition of marine hemipelagic marls in the Vera Basin (Cuevas del Almanzora section) within the Betic Strait: (1) early Pliocene, representing the "Zanclean Deluge" (Cita et al., 1980), (2) Messinian (˜5.7 Ma), representing the last marine stage before the Messinian salinity crisis (Benson and Rakic-El Bied, 1991; Benson et al., 1991). The strontium isotopic ratio on mixed assemblages of foraminifers from these marine marls was determined in order to assess their ages. The average 87Sr/86Sr (0.709033±24) of the seven measured samples is, compared to the base of the Miocene/Pliocene boundary stratotype at Capo Rossello, Sicily, higher by 38 × 10-6 and yields an age of 4.6±0.5 Ma when compared to the established open ocean Sr seawater curve. The determined age indicates that (1) the first 3.6 m of marine deposits of the Cuevas del Almanzora section sensu Cita et al. (1980) including the passage zone are Pliocene, (2) the earliest marine Pliocene might not be represented at Cuevas del Almanzora indicating that this marginal basin at the edge of the Mediterranean Sea, yet within the former Betic Strait, was filled progressively by a marine transgression originating from the Mediterranean Sea around 4.6 Ma. The absence of lowermost Pliocene sediments could suggest that the Betic Strait did not serve as a conduit for the water masses entering the Mediterranean basins during the early Pliocene; and (3) the presence of an early evolutionary stage of Globorotalia margaritae in the Moroccan Bou Regreg section

  20. Surface-air mercury fluxes across Western North America: A synthesis of spatial trends and controlling variables

    USGS Publications Warehouse

    Eckley, Chris S.; Tate, Michael T.; Lin, Che-Jen; Gustin, Mae S.; Dent, Stephen; Eagles-Smith, Collin A.; Lutz, Michelle A; Wickland, Kimberly; Wang, Bronwen; Gray, John E.; Edwards, Grant; Krabbenhoft, David P.; Smith, David

    2016-01-01

    Mercury (Hg) emission and deposition can occur to and from soils, and are an important component of the global atmospheric Hg budget. This paper focuses on synthesizing existing surface-air Hg flux data collected throughout the Western North American region and is part of a series of geographically focused Hg synthesis projects. A database of existing Hg flux data collected using the dynamic flux chamber (DFC) approach from almost a thousand locations was created for the Western North America region. Statistical analysis was performed on the data to identify the important variables controlling Hg fluxes and to allow spatiotemporal scaling. The results indicated that most of the variability in soil-air Hg fluxes could be explained by variations in soil-Hg concentrations, solar radiation, and soil moisture. This analysis also identified that variations in DFC methodological approaches were detectable among the field studies, with the chamber material and sampling flushing flow rate influencing the magnitude of calculated emissions. The spatiotemporal scaling of soil-air Hg fluxes identified that the largest emissions occurred from irrigated agricultural landscapes in California. Vegetation was shown to have a large impact on surface-air Hg fluxes due to both a reduction in solar radiation reaching the soil as well as from direct uptake of Hg in foliage. Despite high soil Hg emissions from some forested and other heavily vegetated regions, the net ecosystem flux (soil flux + vegetation uptake) was low. Conversely, sparsely vegetated regions showed larger net ecosystem emissions, which were similar in magnitude to atmospheric Hg deposition (except for the Mediterranean California region where soil emissions were higher). The net ecosystem flux results highlight the important role of landscape characteristics in effecting the balance between Hg sequestration and (re-)emission to the atmosphere.

  1. Riverine transport of terrestrial organic matter to the North Catalan margin, NW Mediterranean Sea

    NASA Astrophysics Data System (ADS)

    Sanchez-Vidal, Anna; Higueras, Marina; Martí, Eugènia; Liquete, Camino; Calafat, Antoni; Kerhervé, Philippe; Canals, Miquel

    2013-11-01

    Rivers are the primary pathway for organic matter transport from the terrestrial to the marine environment and, thus, river fluxes are critical in regulating the quantity of terrestrial organic matter that reaches the coastal ecosystems. Hydrodynamic processes typical of the coastal zone can lead to the transport of terrestrial organic matter across the continental shelf and beyond. Such organic matter can eventually reach the deep margin and basin ecosystems. Riverine inputs of organic matter to the sea can be a significant food source to marine ecosystems contributing to carbon cycling in these ecosystems. In order to assess the marine carbon cycle it is essential to know the biogeochemical characteristics and temporal dynamics of the fluvial organic matter input discharged by rivers to the coastal zone. In this study we present a one and a half year long (November 2008 to May 2010) assessment on organic carbon (OC) and nitrogen (N) inputs from the three main rivers discharging into the North Catalan margin (Tordera, Ter and Fluvià, from south to north). Furthermore, we investigate the characteristics of the particulate organic matter discharged by these rivers by means of stable isotopic (δ13C and δ15N) and grain size analyses. We found that the hydrological regime of the rivers is a relevant factor in regulating the quantity and mediating the quality of organic matter inputs to the North Catalan margin. Overall, the three main rivers discharging into the study area deliver 1266 and 159 tonnes of terrestrial OC and N per year, respectively, to the coastal zone. Most of the OC and N load is transported during floods, which indicates that the Mediterranean climate of the area, with a strong seasonal contrast in precipitation, determines the timing of the main inputs of OC and N to the sea. Therefore, the annual OC and N load experiences a high temporal variability associated to the number and magnitude of floods with in each hydrological year. In addition, we

  2. Gone with the plate: the opening of the Western Mediterranean basin drove the diversification of ground-dweller spiders

    PubMed Central

    2011-01-01

    Background The major islands of the Western Mediterranean--Corsica, Sardinia, and the Balearic Islands--are continental terrenes that drifted towards their present day location following a retreat from their original position on the eastern Iberian Peninsula about 30 million years ago. Several studies have taken advantage of this well-dated geological scenario to calibrate molecular rates in species for which distributions seemed to match this tectonic event. Nevertheless, the use of external calibration points has revealed that most of the present-day fauna on these islands post-dated the opening of the western Mediterranean basin. In this study, we use sequence information of the cox1, nad1, 16S, L1, and 12S mitochondrial genes and the 18S, 28S, and h3 nuclear genes, along with relaxed clock models and a combination of biogeographic and fossil external calibration points, to test alternative historical scenarios of the evolutionary history of the ground-dweller spider genus Parachtes (Dysderidae), which is endemic to the region. Results We analyse 49 specimens representing populations of most Parachtes species and close relatives. Our results reveal that both the sequence of species formation in Parachtes and the estimated divergence times match the geochronological sequence of separation of the main islands, suggesting that the diversification of the group was driven by Tertiary plate tectonics. In addition, the confirmation that Parachtes diversification matches well-dated geological events provides a model framework to infer substitution rates of molecular markers. Divergence rates estimates ranged from 3.5% My-1 (nad1) to 0.12% My-1 (28S), and the average divergence rate for the mitochondrial genes was 2.25% My-1, very close to the "standard" arthropod mitochondrial rate (2.3% My-1). Conclusions Our study provides the first unequivocal evidence of terrestrial endemic fauna of the major western Mediterranean islands, whose origin can be traced back to the

  3. Pigment distribution and primary production in the western Mediterranean as derived and modeled from coastal zone color scanner observations

    NASA Astrophysics Data System (ADS)

    Morel, André; André, Jean-Michel

    1991-07-01

    A set of 114 coastal zone color scanner (CZCS) images of the western Mediterranean (mainly in the year 1981) have been processed and analyzed to describe the algal biomass evolution and estimate its potential carbon fixation. For that, the pigment concentration in the top layer, Csat, is used through empirical relationships to infer the depth-integrated pigment content of the productive column, tot. A spectral light-photosynthesis model driven by tot is operated with additional information, namely, about sea temperature and photosynthetically available radiation (computed from astronomical and atmospherical parameters then combined with a cloud climatology). This model also includes a standard set of physiological parameters which account for the light capture by algae and for the use of this radiant energy in photosynthesis. This model allows a climatology of ψ* the cross section for photosynthesis per unit of areal chlorophyll, to be produced and then convoluted with the biomass maps after they have been averaged and composited. On average and for the whole western Mediterranean, the pigment concentration in the upper layer is about 0.25 mg Chl m-3, leading to an areal mean concentration of 21 mg Chl m-2. The maximum (bloom) occurs in early May in all zones. Seasonal variations in algal biomass are much more marked in the northern part than in the southern part (apart from Alboran Sea); the south Tyrrhenian basin and the central part of the Algerian basin are steadily oligotrophic. The mean annual carbon fixation rate for the whole basin is about 94 g C m-2 yr-1, or 106 and 87, for the northern and southern basins when separately considered. The seasonality is expressed by a six-fold change in the production rate (between February and May) within the northern zone, whereas only a two-fold change occurs in the southern zone between the same months. These estimates, which compare well with previous episodic field data, considerably extend our knowledge of

  4. Multiproxy assessment of Holocene relative sea-level changes in the western Mediterranean: sea-level variability and improvements in the definition of the isostatic signal

    NASA Astrophysics Data System (ADS)

    Vacchi, Matteo; Rovere, Alessio; Marriner, Nick; Morhange, Christophe; Spada, Giorgio; Fontana, Alessandro

    2016-04-01

    After the review of 918 radiocarbon dated Relative Sea-Level (RSL) data-points we present here the first quality-controlled database constraining the Holocene sea-level histories of the western Mediterranean Sea (Spain, France, Italy, Slovenia, Croatia, Malta and Tunisia). We reviewed and standardized the geological RSL data-points using a new multi-proxy methodology based on: (1) modern taxa assemblages in Mediterranean lagoons and marshes; (2) beachrock characteristics (cement fabric and chemistry, sedimentary structures); and (3) the modern distribution of Mediterranean fixed biological indicators. These RSL data-points were coupled with the large number of archaeological RSL indicators available for the western Mediterranean. We assessed the spatial variability of RSL histories for 22 regions and compared these with the ICE-5G VM2 GIA model. In the western Mediterranean, RSL rose continuously for the whole Holocene with a sudden slowdown at ~7.5 ka BP and a further deceleration during the last ~4.0 ka BP, after which time observed RSL changes are mainly related to variability in isostatic adjustment. The sole exception is southern Tunisia, where data show evidence of a mid-Holocene high-stand compatible with the isostatic impacts of the melting history of the remote Antarctic ice sheet. Our results indicate that late-Holocene sea-level rise was significantly slower than the current one. First estimates of GIA contribution indicate that, at least in the northwestern sector, it accounts at least for the 25-30% of the ongoing sea-level rise recorded by Mediterranean tidal gauges. Such contribution is less constrained at lower latitudes due to the lower quality of the late Holocene index points. Future applications of spatio-temporal statistical techniques are required to better quantify the gradient of the isostatic contribution and to provide improved context for the assessment of 20th century acceleration of Mediterranean sea-level rise.

  5. Coralligenous "atolls": discovery of a new morphotype in the Western Mediterranean Sea.

    PubMed

    Bonacorsi, Marina; Pergent-Martini, Christine; Clabaut, Philippe; Pergent, Gérard

    2012-01-01

    Coralligenous habitat and rhodoliths beds are very important in terms of biodiversity in the Mediterranean Sea. During an oceanographic campaign, carried out in northern Cap Corse, new coralligenous structures have been discovered. These structures, never previously identified in the Mediterranean Sea, are named "coralligenous atolls" because of their circular shape. The origin and growth dynamics of these atolls are still unknown but their form does not appear to result from hydrodynamic action and an anthropogenic origin also seems unlikely. However, this kind of shape seems rather closer to that of other circular structures (e.g. pockmarks) the origin of which is related to gaseous emissions. Further studies are needed to confirm this hypothesis through chemical analysis. PMID:23199634

  6. Distributions of Pu, Am and Cs in margin sediments from the western Mediterranean (Spanish coast).

    PubMed

    Gascó, C; Antón, M P; Pozuelo, M; Meral, J; González, A M; Papucci, C; Delfanti, R

    2002-01-01

    Continental margins are important areas to be considered when studying the distributions and depositions of pollutants, both conventional and radioactive. Coastal sediments accumulate most of those contaminants which can be introduced following atmospheric and/or fluvial pathways. Moreover, their residence times within the water column are usually shortened due to their affinity to associate with the downward falling particulate matter, more abundant at shallower depths. In this paper the distribution profiles and inventories of plutonium, americium and cesium are detailed, providing useful information about recent sedimentation phenomena such as sediment mixing, slumping processes and bioturbation. Unsupported 210Pb data are used as reliable indicators of enhanced/reduced deposition events. Also, the calculated inventories have enabled the estimation of the radiological contribution of the Spanish Mediterranean margin to the total radioactivity deposited onto the Mediterranean sea floor.

  7. Coralligenous "atolls": discovery of a new morphotype in the Western Mediterranean Sea.

    PubMed

    Bonacorsi, Marina; Pergent-Martini, Christine; Clabaut, Philippe; Pergent, Gérard

    2012-01-01

    Coralligenous habitat and rhodoliths beds are very important in terms of biodiversity in the Mediterranean Sea. During an oceanographic campaign, carried out in northern Cap Corse, new coralligenous structures have been discovered. These structures, never previously identified in the Mediterranean Sea, are named "coralligenous atolls" because of their circular shape. The origin and growth dynamics of these atolls are still unknown but their form does not appear to result from hydrodynamic action and an anthropogenic origin also seems unlikely. However, this kind of shape seems rather closer to that of other circular structures (e.g. pockmarks) the origin of which is related to gaseous emissions. Further studies are needed to confirm this hypothesis through chemical analysis.

  8. Variability of fine and coarse aerosol over the Western Mediterranean Basin during the Minerva 2015 research cruise campaign

    NASA Astrophysics Data System (ADS)

    Castagna, Jessica; Carbone, Francesco; Naccarato, Attilio; Moretti, Sacha; Esposito, Giulio; Bencardino, Mariantonia; D'Amore, Francesco; Sprovieri, Francesca; Pirrone, Nicola

    2016-04-01

    The Mediterranean Basin, due to its semi-enclosed configuration, is heavily affected by air pollution and it is becoming, in the last years, a region of particular interest of study for its implications regarding both health effects and environmental impacts. The area is surrounded by a densely populated as well as industrialized coast, and even affected by natural sources. So, it is important to know how the various sources contributes to increase air pollution levels and discriminate among them. With special regard to aerosol pollution, natural sources, like Saharan dust, volcanoes, and fires, as well as anthropogenic sources, such as industry, road and marine traffic, and fuel combustion from heating, can equally increase the values of this dangerous pollutant. While on the land we can find numerous monitoring sites, there are not continuous measurements on the sea. For this reason, since 2000 the Institute of Atmospheric Pollution of the National Research Council (CNR-IIA) is conducting regular oceanographic campaigns of measurements in the Mediterranean Sea. In this context, here we report the results obtained during the last cruise campaign, which took place in the Western Mediterranean sector and was conducted on-board the Italian research vessel Minerva during summer 2015 (from June 27th to July 13th). Fine (PM2.5) and Coarse (PM2.5-10) particulate size fractions were collected on PTFE membrane filters (Advantec MFS) and their mass concentrations determined gravimetrically. Successively, all the filters were digested with a mixture of HNO3/H2O2 in an microwaves digestion system and then analyzed by ICP-MS for the determination of the major and trace elements. Outcomes regarding the particulate mass concentration, the content and the distribution of the analyzed elements over both PM size fractions will be discussed taking into account potential contributing sources as well as different meteorological conditions.

  9. Late Pleistocene Climatic Changes in the Western Mediterranean Inferred from Temperature, Productivity and Eolian Input Records: Implications for Human Dispersal

    NASA Astrophysics Data System (ADS)

    Hambach, B.; Rosell Mele, A.; Martinez-Garcia, A.

    2009-12-01

    The relation between climate and hominid dispersal has yet a number of unsettled issues, largely due to the lack of regional climate records in areas with significant hominid remains. Scientific evidence from the Mediterranean region indicates that humans evolved into their present form during key climatic intervals as indicated by the records of the earliest Europeans from Atapuerca (Spain) and Dmanisi (Georgia). However, it remains unclear which route was used by the early hominids to populate Europe (via the strait of Gibraltar or the Levantine Corridor). In this sense, it is still not clear if the climatic conditions during this period were favorable for hominid crossing via the strait of Gibraltar or not. To gain a better insight into the Iberian peninsular climate during the late Pleistocene, a marine sediment core from the Alboran Sea, Western Mediterranean, is used to reconstruct climate relevant variables related to surface ocean and atmospheric circulation by applying a set of organic geochemical proxies (biomarkers). In a first approach we present high resolution data (2 ky) for the interval from 0 to 500 ky. The results of this multi-biomarker analysis give new insights into past ocean climate conditions as well as into the processes that occurred onshore during this period. The reconstruction of sea surface temperatures is done by the analysis of alkenones (UK37-index). Total chlorins concentration is used as proxy for paleoproductivity. Terrestrial eolian inputs and vegetation changes are determined by the analysis of n-alkyl compounds (long chain n-alkanes, n-alkenols and n-alkanoic acids) which are major components of leaf waxes from terrestrial higher plants. Like mineral aerosols, these compounds are wind-transported from local vegetation sources to adjacent oceans where the particles settle and are preserved in ocean sediments with very little diagenetic alteration. These biomarkers offer a promising tool for reconstructing terrestrial vegetation

  10. Invasion of the red seaweed Heterosiphonia japonica spans biogeographic provinces in the Western North Atlantic Ocean.

    PubMed

    Newton, Christine; Bracken, Matthew E S; McConville, Megan; Rodrigue, Katherine; Thornber, Carol S

    2013-01-01

    The recent invasion of the red alga Heterosiphonia japonica in the western North Atlantic Ocean has provided a unique opportunity to study invasion dynamics across a biogeographical barrier. Native to the western North Pacific Ocean, initial collections in 2007 and 2009 restricted the western North Atlantic range of this invader to Rhode Island, USA. However, through subtidal community surveys, we document the presence of Heterosiphonia in coastal waters from Maine to New York, USA, a distance of more than 700 km. This geographical distribution spans a well-known biogeographical barrier at Cape Cod, Massachusetts. Despite significant differences in subtidal community structure north and south of Cape Cod, Heterosiphonia was found at all but two sites surveyed in both biogeographic provinces, suggesting that this invader is capable of rapid expansion over broad geographic ranges. Across all sites surveyed, Heterosiphonia comprised 14% of the subtidal benthic community. However, average abundances of nearly 80% were found at some locations. As a drifting macrophyte, Heterosiphonia was found as intertidal wrack in abundances of up to 65% of the biomass washed up along beaches surveyed. Our surveys suggest that the high abundance of Heterosiphonia has already led to marked changes in subtidal community structure; we found significantly lower species richness in recipient communities with higher Heterosiphona abundances. Based on temperature and salinity tolerances of the European populations, we believe Heterosiphonia has the potential to invade and alter subtidal communities from Florida to Newfoundland in the western North Atlantic.

  11. Hydrogeological features conditioning trophic levels of quarry lakes in western Po plain (north-western Italy)

    NASA Astrophysics Data System (ADS)

    De Luca, Domenico Antonio; Castagna, Sara; Lasagna, Manuela

    2013-04-01

    Quarry lakes occur in plains areas due to the extraction of alluvial sand and gravel used for grout and concrete in the construction industry. Excavation depths can reach and intersect the groundwater surface, thus creating a lake. Because of the need to optimize efficiency, the number of active open pit mines has increased in recent years; consequently, the global number of pit lakes will increase in coming decades (Castendyk and Eary 2009; Klapper and Geller 2001; Castro and Moore 2000). Similar to natural lakes, pit lakes are subject to eutrophication process, both during and after quarrying activity; during mining activity, the eutrophic level is strongly controlled by the excavation method. In the Piedmont territory (north-western Italy) there are 70 active quarry lakes, corresponding to approximately 0.1% of the entire plain area. Quarry lakes, located primarily along the main rivers occur in alluvial deposits of the plain area and have average depths between 20 and 30 m (maximum of 60 m deep) and surface areas between 3 and 30 hectares (Castagna 2008). The present study describes the trophic status of 23 active quarry lakes in the Piedmont plain that were evaluated by applying classifications from scientific literature. Currently, the majority of the studied quarry lakes may be defined as mesotrophic or eutrophic according to the trophic state classifications. Based on historic data, lake trophic levels have increased over time, during active mining. At the end of mining activity, further deterioration of water quality was expected, especially for smaller lakes with minimal oxygen stratification and higher levels of nutrients and algal growth. In addition, the paper focuses on the pit lake water quality and pit dimension; From an environmental perspective the excavation of quarry lakes with an appreciable size will likely result in a better safeguard of water quality and enhanced possibilities for lake end use after the cessation of mining. Piedmont quarry

  12. Evolution of hydraulic traits in closely related species pairs from Mediterranean and nonMediterranean environments of North America.

    PubMed

    Bhaskar, Radika; Valiente-Banuet, Alfonso; Ackerly, David D

    2007-01-01

    Chaparral shrubs in California experience cool, wet winters and hot, dry summers characteristic of mediterranean-type climates; by contrast, morphologically similar close relatives in central Mexico experience summer rainfall. A comparison of closely related species pairs was conducted to examine whether evolutionary divergences in plant hydraulic conductivity were associated with contrasting seasonality of precipitation. Six species pairs in Santa Barbara, California and Tehuacan, Mexico were chosen to test for repeated directional divergences across the habitat contrast. Additionally, evolutionary correlations were examined using phylogenetically independent contrasts (PICs) among a suite of hydraulic traits, including stem- and leaf-specific conductivity, resistance to embolism, wood density, inverse Huber value, and minimum seasonal water potential. Leaf-specific conductivity was generally higher in California, but for most hydraulic traits the species pairs exhibited varied evolutionary trajectories across the climate contrast. A significant correlation was found between divergences in xylem resistance to embolism and minimum seasonal water potential, but no evolutionary trade-off was found between resistance and stem conductivity. Higher leaf-specific conductivity may be adaptive in California, where soil and atmospheric droughts coincide during summer months. This response is consistent with a hydraulic strategy of high leaf water supply under high evaporative demand to prevent excessive drops in water potential.

  13. Slab dragging and the recent geodynamic evolution of the western Mediterranean plate boundary region

    NASA Astrophysics Data System (ADS)

    Spakman, Wim; Chertova, Maria V.; van den Berg, Arie P.; Thieulot, Cedric; van Hinsbergen, Douwe J. J.

    2016-04-01

    The Tortonian-Present geodynamic evolution of the plate boundary between North Africa and Iberia is characterized by first-order enigmas. This concerns, e.g., the diffuse tectonic activity of the plate boundary; the crustal thickening below the Rif; the closing of the northern Moroccan marine gateways prior to the Messinian Salinity Crisis; crustal extension of the central to eastern Betics; the origin and sense of motion of the large left-lateral Trans Alboran Shear Zone (TASZ) and Eastern Betic Shear Zone (EBSZ); and lithosphere delamination of the North African continental edge. Many explanations have been given for each of these seemingly disparate tectonic features, which invariably have been addressed in the plate tectonic context of the NW-SE relative plate convergence between the major plates since the Tortonian, mostly independently from each other. Usually there is no clear role for the subducted slab underlying the region, except for presumed rollback, either to SW or to the W, depending on the type of observations that require explanation. Here we integrate the dynamic role of the slab with the NW-SE relative plate convergence by 3-D numerical modelling of the slab evolution constrained by absolute plate motions (Chertova et al., JGR,2014 & Gcubed 2014). By combining observations and predictions from seismology, geology, and geodesy, with our numerical 3-D slab-mantle dynamics modelling, we developed a new and promising geodynamic framework that provides explanations of all noted tectonic enigmas in a coherent and connected way. From the Tortonian until today, we propose that mantle-resisted slab dragging combines with the NW-SE plate convergence across the (largely) unbroken plate boundary to drive the crustal deformation of the region. Slab dragging is the lateral transport, pushing or pulling, of slab through the mantle by the absolute motion of the subducting plate (Chertova et al., Gcubed, 2014). Because the slab is connected to both the Iberian

  14. Do submarine landslides and turbidites provide a faithful record of large magnitude earthquakes in the Western Mediterranean?

    NASA Astrophysics Data System (ADS)

    Clare, Michael

    2016-04-01

    Large earthquakes and associated tsunamis pose a potential risk to coastal communities. Earthquakes may trigger submarine landslides that mix with surrounding water to produce turbidity currents. Recent studies offshore Algeria have shown that earthquake-triggered turbidity currents can break important communication cables. If large earthquakes reliably trigger landslides and turbidity currents, then their deposits can be used as a long-term record to understand temporal trends in earthquake activity. It is important to understand in which settings this approach can be applied. We provide some suggestions for future Mediterranean palaeoseismic studies, based on learnings from three sites. Two long piston cores from the Balearic Abyssal Plain provide long-term (<150 ka) records of large volume turbidites. The frequency distribution form of turbidite recurrence indicates a constant hazard rate through time and is similar to the Poisson distribution attributed to large earthquake recurrence on a regional basis. Turbidite thickness varies in response to sea level, which is attributed to proximity and availability of sediment. While mean turbidite recurrence is similar to the seismogenic El Asnam fault in Algeria, geochemical analysis reveals not all turbidites were sourced from the Algerian margin. The basin plain record is instead an amalgamation of flows from Algeria, Sardinia, and river fed systems further to the north, many of which were not earthquake-triggered. Thus, such distal basin plain settings are not ideal sites for turbidite palaoeseimology. Boxcores from the eastern Algerian slope reveal a thin silty turbidite dated to ~700 ya. Given its similar appearance across a widespread area and correlative age, the turbidite is inferred to have been earthquake-triggered. More recent earthquakes that have affected the Algerian slope are not recorded, however. Unlike the central and western Algerian slopes, the eastern part lacks canyons and had limited sediment

  15. Trophodynamics of suprabenthic fauna on coastal muddy bottoms of the southern Tyrrhenian Sea (western Mediterranean)

    NASA Astrophysics Data System (ADS)

    Fanelli, E.; Cartes, J. E.; Badalamenti, F.; Rumolo, P.; Sprovieri, M.

    2009-02-01

    The trophodynamics of suprabenthic fauna were analyzed in the Gulf of Castellammare (North-western Sicily, Italy) at depths ranging between 40 and 80 m. Variations in species abundance and biomass together with changes in nitrogen and carbon stable isotope composition were explored at a seasonal scale, from November 2004 to June 2005. Suprabenthos showed maximum biomass and abundance from late winter to summer, while minimum values were found in autumn. The highest abundances of mysids and copepods occurred in March, 1 month after the peak of primary production. Amphipod abundance was higher in summer, likely due to a relative increase in organic matter in the sediments. Statistical analysis provided evidence for separation of sample abundances as a function of season. The best match between suprabenthos abundance and environmental variables was found with Chlorophyll a recorded 3 months before the sampling. Stable isotope analyses suggest a relatively complex food web in the Gulf of Castellammare with several potential food sources. Some suprabenthic species (i.e. mysids and copepods) exhibited depleted values of δ13C, indicating a planktonic source of nutrition. Cumaceans and amphipods displayed more enriched δ13C values, pointing to more detritivorous behaviour. A third group with intermediate δ13C values comprised species with a mixed diet (e.g. Ampelisca spp., Apherusa vexatrix and Harpinia spp.). Assuming a 15N-enrichment of ca. 2.54‰ between consumers and their diet, at least two trophic levels can be distinctly identified: (1) filter feeders/grazers (mysids, copepods), suspension/deposit feeders ( Ampelisca spp., A. vexatrix, small Goneplax rhomboides) and omnivores, alternatively feeding on detritus and small invertebrates such as meiobenthos (the cumacean Leucon mediterraneus or the amphipod Westwoodilla rectirostris); (2) carnivores on small crustaceans and zooplankton (the amphipod Harpinia spp., the gobiid fish Lesuerigobius suerii and the decapod

  16. Response of rocky reef top predators (Serranidae: Epinephelinae) in and around marine protected areas in the Western Mediterranean Sea.

    PubMed

    Hackradt, Carlos Werner; García-Charton, José Antonio; Harmelin-Vivien, Mireille; Pérez-Ruzafa, Ángel; Le Diréach, Laurence; Bayle-Sempere, Just; Charbonnel, Eric; Ody, Denis; Reñones, Olga; Sanchez-Jerez, Pablo; Valle, Carlos

    2014-01-01

    Groupers species are extremely vulnerable to overfishing and many species are threatened worldwide. In recent decades, Mediterranean groupers experienced dramatic population declines. Marine protected areas (MPAs) can protect populations inside their boundaries and provide individuals to adjacent fishing areas through the process of spillover and larval export. This study aims to evaluate the effectiveness of six marine reserves in the Western Mediterranean Sea to protect the populations of three species of grouper, Epinephelus marginatus, Epinephelus costae and Mycteroperca rubra, and to understand in which circumstances MPAs are able to export biomass to neighbouring areas. All the studied MPAs, except one where no grouper was observed, were able to maintain high abundance, biomass and mean weight of groupers. Size classes were more evenly distributed inside than outside MPAs. In two reserves, biomass gradients could be detected through the boundaries of the reserve as an indication of spillover. In some cases, habitat structure appeared to exert a great influence on grouper abundance, biomass and mean individual weight, influencing the gradient shape. Because groupers are generally sedentary animals with a small home range, we suggest that biomass gradients could only occur where groupers attain sufficient abundance inside MPA limits, indicating a strongly density-dependent process. PMID:24905331

  17. Response of Rocky Reef Top Predators (Serranidae: Epinephelinae) in and Around Marine Protected Areas in the Western Mediterranean Sea

    PubMed Central

    Hackradt, Carlos Werner; García-Charton, José Antonio; Harmelin-Vivien, Mireille; Pérez-Ruzafa, Ángel; Le Diréach, Laurence; Bayle-Sempere, Just; Charbonnel, Eric; Ody, Denis; Reñones, Olga; Sanchez-Jerez, Pablo; Valle, Carlos

    2014-01-01

    Groupers species are extremely vulnerable to overfishing and many species are threatened worldwide. In recent decades, Mediterranean groupers experienced dramatic population declines. Marine protected areas (MPAs) can protect populations inside their boundaries and provide individuals to adjacent fishing areas through the process of spillover and larval export. This study aims to evaluate the effectiveness of six marine reserves in the Western Mediterranean Sea to protect the populations of three species of grouper, Epinephelus marginatus, Epinephelus costae and Mycteroperca rubra, and to understand in which circumstances MPAs are able to export biomass to neighbouring areas. All the studied MPAs, except one where no grouper was observed, were able to maintain high abundance, biomass and mean weight of groupers. Size classes were more evenly distributed inside than outside MPAs. In two reserves, biomass gradients could be detected through the boundaries of the reserve as an indication of spillover. In some cases, habitat structure appeared to exert a great influence on grouper abundance, biomass and mean individual weight, influencing the gradient shape. Because groupers are generally sedentary animals with a small home range, we suggest that biomass gradients could only occur where groupers attain sufficient abundance inside MPA limits, indicating a strongly density-dependent process. PMID:24905331

  18. Response of rocky reef top predators (Serranidae: Epinephelinae) in and around marine protected areas in the Western Mediterranean Sea.

    PubMed

    Hackradt, Carlos Werner; García-Charton, José Antonio; Harmelin-Vivien, Mireille; Pérez-Ruzafa, Ángel; Le Diréach, Laurence; Bayle-Sempere, Just; Charbonnel, Eric; Ody, Denis; Reñones, Olga; Sanchez-Jerez, Pablo; Valle, Carlos

    2014-01-01

    Groupers species are extremely vulnerable to overfishing and many species are threatened worldwide. In recent decades, Mediterranean groupers experienced dramatic population declines. Marine protected areas (MPAs) can protect populations inside their boundaries and provide individuals to adjacent fishing areas through the process of spillover and larval export. This study aims to evaluate the effectiveness of six marine reserves in the Western Mediterranean Sea to protect the populations of three species of grouper, Epinephelus marginatus, Epinephelus costae and Mycteroperca rubra, and to understand in which circumstances MPAs are able to export biomass to neighbouring areas. All the studied MPAs, except one where no grouper was observed, were able to maintain high abundance, biomass and mean weight of groupers. Size classes were more evenly distributed inside than outside MPAs. In two reserves, biomass gradients could be detected through the boundaries of the reserve as an indication of spillover. In some cases, habitat structure appeared to exert a great influence on grouper abundance, biomass and mean individual weight, influencing the gradient shape. Because groupers are generally sedentary animals with a small home range, we suggest that biomass gradients could only occur where groupers attain sufficient abundance inside MPA limits, indicating a strongly density-dependent process.

  19. Intestinal helminth fauna of bottlenose dolphin Tursiops truncatus and common dolphin Delphinus delphis from the western Mediterranean.

    PubMed

    Quiñones, Ruth; Giovannini, Anna; Raga, J Antonio; Fernández, Mercedes

    2013-06-01

    We report on the intestinal helminth fauna of 15 bottlenose dolphins Tursiops truncatus and 6 short-beaked common dolphins Delphinus delphis from the western Mediterranean. Eight helminth species were found in bottlenose dolphin, i.e., the digeneans Synthesium tursionis, Brachycladium atlanticum, and Pholeter gastrophilus, the nematode Anisakis sp., and the cestodes Tetrabothrius forsteri, Diphyllobothrium sp., Strobilocephalus triangularis, and tetraphyllidean plerocercoids. Brachycladium atlanticum, S. triangularis , and tetraphyllidean plerocercoids are new host records. No T. forsteri had previously been reported in Mediterranean bottlenose dolphins. Three species of helminths were recorded in the common dolphin, i.e., the digenean Synthesium delamurei (which was a new host record), and the cestodes T. forsteri and tetraphyllidean plerocercoids. The intestinal helminth communities of bottlenose and common dolphins are depauperate, similar to that of other cetacean species, but those from bottlenose dolphins harbored a higher number of helminth species. This study supports the notion that oceanic cetaceans, such as common dolphins, have a comparatively poorer helminth fauna than that of neritic species, such as bottlenose dolphins, because the likelihood of parasite recruitment is decreased.

  20. Adjustment of the tree-ring response of Juniperus thurifera to climate in the Western Mediterranean region

    NASA Astrophysics Data System (ADS)

    Varino, Filipa; DeSoto, Lucia; Trigo, Ricardo M.; Gouveia, Célia; Andrade, José; campelo, Filipe; Nabais, Cristina

    2013-04-01

    Juniperus thurifera L. is a long-lived conifer tree endemic to western Mediterranean region. It is well adapted to continental Mediterranean weather conditions such as negative winter temperatures or summer drought and is capable to maintain the photosynthetic activity all year round, making it a suitable species to study tree-ring sensitivity to climate change. In this work we have used tree-ring width data of J. thurifera trees from six stands located in northern Spain (Soria, Barrios de Luna and Desert of Monegros) and High Atlas in Morocco (Armd, Oukaimeden and Ourika) and correlated with climatic information (temperature and precipitation) from the Climate Research Unity (CRU) database. We have evaluated separately the growth patterns and climatic response of the populations from Spain and Morocco as they showed distinct seasonal dependence to temperature and precipitation. Afterwards, according to the length of both databases (ring-width and surface climate variables), we evaluated the role played by the climatic variables on the species growth pattern through time. We observed an increase of growth sensitivity to summer drought in Spain, whereas such sensitivity was not verify in Morocco"

  1. Millennial-scale Hydrological Fluctuations in Western Mediterranean During the Last 20 ka: The Sedimentary Record of Lake Estanya (NE Spain)

    NASA Astrophysics Data System (ADS)

    Morellon, M.; Valero-Garcés, B.; Moreno, A.; Gonzalez-Samperiz, P.; Rico, M.; Corella, J.; Mata, P.; Martin-Puertas, C.; Anselmetti, F.; Ariztegui, D.; Schnelmann, M.

    2007-12-01

    The impact of North Atlantic changes in Western Mediterranean Sea has been widely documented by marine records (Cacho et al., 2001; Martrat et al., 2004 and 2007; Moreno et al., 2005). Although this teleconnection has also been recorded in several mountain records of northern Spain (Allen et al., 1996; Leira and Santos, 2002; González-Samperiz et al., 2006), the environmental effects and the hydrological amplitude of these fluctuations in continental, low-land areas of Iberian Peninsula are still poorly understood. The multi-proxy study of sediment cores from karstic Lake Estanya (Pre-Pyrenees, NE Spain) provides the first continuous record of the hydrological evolution in this area during the deglaciation. The chronological model, based on 14 AMS radiocarbon dates shows an age of ca. 20,000 calendar years BP for the base of the sequence. Seismic stratigraphy revealed a sedimentary filling up to 15 m thick consisting on three main units identifiable through the lake basin and deposited during the Lateglacial, Early-to-Mid Holocene and Late Holocene, respectively. Sediment analyses have been carried out in cores from the deepest area of the lake. Sedimentary facies have been defined after the integration of sedimentological and mineralogical proxies (X-ray diffraction and SEM), high-resolution analyses of light elements (Al, Si, P, S, K, Ca, Ti, Mn and Fe) by XRF core-scanner and stable isotope analyses of ostracods, carbonate phases and organic matter. Increased run-off and higher lake levels are interpreted from massive, clastic facies while more concentrated waters and shallower conditions were more frequent during deposition of laminated and organogenic gypsum-rich facies. Lateglacial sequence shows fluctuating but shallow lake conditions followed by a large increase in water availability during the Early Holocene and lowered lake levels and arid conditions for the Mid-to-Late Holocene (4.2 - 0.8 ka). Fluctuating but higher lake levels occurred during the last

  2. Body condition of the deep water demersal resources at two adjacent oligotrophic areas of the western Mediterranean and the influence of the environmental features

    NASA Astrophysics Data System (ADS)

    Rueda, L.; Moranta, J.; Abelló, P.; Balbín, R.; Barberá, C.; Fernández de Puelles, M. L.; Olivar, M. P.; Ordines, F.; Ramón, M.; Torres, A. P.; Valls, M.; Massutí, E.

    2014-10-01

    Body condition indices not only are often used as reliable indicators of the nutritional status of individuals but also can they be utilized to provide insights regarding food availability and habitat quality. The aim of this study was to evaluate the connection between the body condition of the demersal species and the environmental features in the water column (i.e. the hydrographic conditions and the potential trophic resources) in two proximate areas, the north and south regions of the Balearic Islands (western Mediterranean), viz., the Balearic sub-basin (BsB) and the Algerian sub-basin (AsB), respectively, with different geomorphological and hydrodynamic features. Body condition indices were calculated for individuals of 21 demersal species including 11 teleosts, 4 elasmobranchs, 3 cephalopods and 3 crustaceans, which represented > 70-77% of the deep water resources, captured by bottom trawling. The morphometric indices, viz., Relative Condition Index (Kn) and Standardised Residuals (SR) from the length-weight relationship, were used. The results for each one of the 21 species indicated a significantly better condition in terms of Kn and SR in the BsB, for 7 and 9 species, respectively. In addition, a general model, including the 21 species together, showed better body condition in the BsB, and during the summer. The spatial and temporal differences in the body condition are discussed in the context of the environmental variables characterising both the study areas, which showed significant variations, for some of the hydrographic features (chlorophyll a, dissolved oxygen, salinity, potential density and temperature), as well as for some of the potential trophic resources (mesopelagic and epibenthic fauna). These findings suggest an environmental effect on the body condition of the deep-water resources in the Balearic Islands, one of the most oligotrophic areas of the western Mediterranean, and reveal more suitable environmental conditions for these species

  3. [Strong genetic differentiation of the gilthead sea bream Sparus aurata (L., 1758) between the two western banks of the Mediterranean].

    PubMed

    Chaoui, Lamya; Kara, M Hichem; Quignard, Jean Pierre; Faure, Eric; Bonhomme, François

    2009-04-01

    We characterised four samples of gilthead sea bream from the two western Mediterranean banks with three microsatellite loci and two RAPDs systems. Contrarily to what could be predicted for a highly mobile species with a planktonic larval dispersal phase, we observed a strong and significant genetic differentiation at all loci between the two banks (F(st)=0.069(***)), whereas two samples from the Gulf of Lions were almost identical (F(st)=0.003 ns) while the two from the Gulf of Annaba displayed varied levels of differentiation according to the molecular marker considered. RAPDs showed a similar trend as microsatellites. The reasons for this surprisingly strong genetic differentiation, as compared to what has been observed in other species over comparable geographical distance, may be sought for either in a smaller as suspected larval dispersal, or in the non-neutrality of the loci studied. PMID:19304263

  4. X-chromosome SNP analyses in 11 human Mediterranean populations show a high overall genetic homogeneity except in North-west Africans (Moroccans)

    PubMed Central

    2008-01-01

    Background Due to its history, with a high number of migration events, the Mediterranean basin represents a challenging area for population genetic studies. A large number of genetic studies have been carried out in the Mediterranean area using different markers but no consensus has been reached on the genetic landscape of the Mediterranean populations. In order to further investigate the genetics of the human Mediterranean populations, we typed 894 individuals from 11 Mediterranean populations with 25 single-nucleotide polymorphisms (SNPs) located on the X-chromosome. Results A high overall homogeneity was found among the Mediterranean populations except for the population from Morocco, which seemed to differ genetically from the rest of the populations in the Mediterranean area. A very low genetic distance was found between populations in the Middle East and most of the western part of the Mediterranean Sea. A higher migration rate in females versus males was observed by comparing data from X-chromosome, mt-DNA and Y-chromosome SNPs both in the Mediterranean and a wider geographic area. Multilocus association was observed among the 25 SNPs on the X-chromosome in the populations from Ibiza and Cosenza. Conclusion Our results support both the hypothesis of (1) a reduced impact of the Neolithic Wave and more recent migration movements in NW-Africa, and (2) the importance of the Strait of Gibraltar as a geographic barrier. In contrast, the high genetic homogeneity observed in the Mediterranean area could be interpreted as the result of the Neolithic wave caused by a large demic diffusion and/or more recent migration events. A differentiated contribution of males and females to the genetic landscape of the Mediterranean area was observed with a higher migration rate in females than in males. A certain level of background linkage disequilibrium in populations in Ibiza and Cosenza could be attributed to their demographic background. PMID:18312628

  5. Tracking regional and global teleconnections recorded by western North American speleothem records

    NASA Astrophysics Data System (ADS)

    Oster, Jessica L.; Kelley, Neil P.

    2016-10-01

    Speleothem proxy records are useful for interrogating past climates in the low and mid-latitudes given their ability to provide continuous, high-resolution, and long-lived records that can be dated with high precision. Several speleothem oxygen isotope records from western North America have recently been developed that highlight the importance of this archive in documenting past changes in atmospheric circulation. Taken individually, these records hint at teleconnections between western North American hydroclimate and climate changes in the high northern latitudes and tropics. However, there has been no systematic investigation of global climate teleconnections to this region that draws upon the body of North American speleothem records as a whole. Here we review the dominant controls on precipitation oxygen isotopes across the region, and conduct statistical comparisons and network visualizations of high-resolution speleothem oxygen isotope records from western North America to investigate the regional response to pronounced climate changes of the last deglaciation and to determine the pattern of global teleconnections to this region. We find that most western North American speleothem oxygen isotope records demonstrate a robust and consistent response to the events of the last deglaciation, despite differing controls on the oxygen isotope ratio of precipitation across the region. One record that receives a strong influence from the Gulf of Mexico exhibits a contrasting pattern in oxygen isotopes relative to most of the other records, which are dominated by westerly storms generated in the Pacific. During the studied interval, major shifts in Western North American speleothem records appear broadly synchronous at least within the uncertainty of age models. We also find strong statistical linkages between western North American speleothem records and speleothem records of Asian monsoon variability and other records from regions directly influenced by movement of

  6. Phylogenetic relationships of Western Mediterranean West Nile virus strains (1996-2010) using full-length genome sequences: single or multiple introductions?

    PubMed

    Sotelo, Elena; Fernández-Pinero, Jovita; Llorente, Francisco; Vázquez, Ana; Moreno, Ana; Agüero, Montserrat; Cordioli, Paolo; Tenorio, Antonio; Jiménez-Clavero, Miguel Ángel

    2011-11-01

    In recent years, West Nile virus (WNV) has re-emerged in the Western Mediterranean region. As a result, the number of complete WNV genome sequences available from this region has increased, allowing more detailed phylogenetic analyses, which may help to understand the evolutionary history of WNV circulating in the Western Mediterranean. To this aim, the present work describes six new complete WNV sequences from recent outbreaks and surveillance in Italy in 2008-2009 and in Spain in 2008 and 2010. Comparison with other sequences from different WNV clusters within lineage 1 (clade 1a) confirmed that all Western Mediterranean WNV isolates obtained since 1996 (except one from Tunisia, collected in 1997) cluster in a single monophyletic group (here called 'WMed' subtype). The analysis differentiated two subgroups within this subtype, which appear to have evolved from earlier WMed strains, suggesting a single introduction in the area, and further dissemination and evolution. Close similarities between WNV variants circulating in consecutive years, one in Spain, between 2007 and 2008, and another in Italy between 2008 and 2009, suggest that the virus possibly overwinters in Western Mediterranean sites. The NS3(249)-proline genotype, recently proposed as a virulence determinant for WNV, has arisen independently at least twice in the area. Overall, these results indicate that the frequent recurrence of outbreaks caused by phylogenetically homogeneous WNV in the Western Mediterranean since 1996 is consistent with a single introduction followed by viral persistence in endemic foci in the area, rather than resulting from independent introductions from exogenous endemic foci.

  7. The role of lantern fish (Myctophidae) in the life-cycle of cetacean parasites from western Mediterranean waters

    NASA Astrophysics Data System (ADS)

    Mateu, Paula; Nardi, Valentina; Fraija-Fernández, Natalia; Mattiucci, Simonetta; Gil de Sola, Luis; Raga, Juan Antonio; Fernández, Mercedes; Aznar, Francisco Javier

    2015-01-01

    Myctophids (lantern fish) and cephalopods play a key role in trophic webs from the continental slope and oceanic waters linking the zooplankton to top predators. Many cetaceans feed on both lantern fish and cephalopods, and such prey would thus be expected to bridge the trophic gap in the life-cycles of helminths infecting cetaceans. However, information on the life-cycles of most of these helminths is extremely scanty. We examined the parasite fauna of myctophids and cephalopods in two areas from the western Mediterranean where at least 21 helminth taxa from cetaceans have been reported and both cetacean diversity and abundance is high. A total of 1012 individuals of 8 lantern fish species, namely, Ceratoscopelus maderensis, Lampanyctus crocodilus, Notoscopelus elongatus, Benthosema glaciale, Myctophum punctatum, Lobianchia dofleini, Diaphus holti and Hygophum benoiti, and 792 individuals of 2 cephalopod species, Alloteuthis media and Sepietta oweniana, were collected from the Gulf of Valencia and Alboran Sea (Spanish Mediterranean) during 2010-2012 and examined for larval helminths. All these species have been reported as prey for at least some cetacean species in the area. Only five helminth taxa were found. The nematodes Anisakis pegreffii and Anisakis physeteris were detected in N. elongatus and C. maderensis (overall prevalence for Anisakis: 8.1% and 0.5%, respectively). Their prevalence in N. elongatus was significantly higher than that from the other three myctophid species with n>50 individuals. A single individual of Hysterothylacium sp. was found in N. elongatus (prevalence: 0.5%) and Raphidascarididae gen. spp. in N. elongatus and L. crocodilus (prevalence: 20.3% and 0.7%, respectively). Juvenile didymozoid digeneans (Torticaecum type) were detected in N. elongatus and L. crocodilus (prevalence: 18.5% and 4.3%, respectively). Two unidentified cestode plerocercoids were collected from N. elongatus. Our study suggests, for the first time, that myctophids

  8. Clay Mineral Assemblages as Proxies for Reconstructing Messinian Paleoenvironments in the Western Mediterranean

    NASA Astrophysics Data System (ADS)

    Martinez-Ruiz, Francisca; Comas, Menchu; Vasconcelos, Crisogono

    2014-05-01

    Significant tectonic and climate changes at time of the Messinian Salinity Crisis (MSC) led to a complex sedimentation involving marked changes in sediment composition, particularly in clay mineral assemblages. One of the noticeable mineralogical changes across this time interval is the strong smectite increase in Messinian deposits in comparison to the underlying Tortonian and overlaying Pliocene sediments. As no break in the clay mineralogy is recognized in the open ocean (Chamley et al., 1978), such changes are also distinctive of the Mediterranean basins. Since the early discoveries of the giant Messinian evaporite formation (DSDP Legs 13 and 42A), a vast literature contributed, during the last decades, to the continuous debate and re-examination of the actual Messinian paleoenvironment. Drilled records in the westernmost Mediterranean (Alboran Sea) have shown significant changes in the mineralogical assemblages associated to the Messinian events. This basin is depleted of significant salt deposits. Site 976 (ODP Leg 161) recovered a 670-m-thick, middle Miocene (Serravallian) to Pleistocene/Holocene sedimentary sequence, including a thin interval of Messinian sediment, lying directly upon the metamorphic basement. Analysis of clay mineral assemblages from the sedimentary cover of Hole 976B revealed an homogeneous clay association composed of illite, smectite, chlorite and kaolinite with no major changes in clay mineral abundances except for the sediment interval dated as Messinian, which is characterized by a sharp smectite increase (Martinez-Ruiz et al., 1999). Transmission Electron Microscope analyses of clay minerals revealed that smectite composition corresponds to Al-rich beidellites, which supports the existence of such smectites in peri-Mediterranean soils. Smectite formation was favored by the climate conditions at that time, comprising progressive aridification and the alternation of wet and dry climatic episodes. Diagenesis in these smectites is

  9. Late-Pleistocene evolution of the East Mediterranean shallow continental shelf of north-central Israel

    NASA Astrophysics Data System (ADS)

    Shtienberg, Gilad; Dix, Justin; Waldmann, Nicolas; Makovsky, Yizhaq; Bookman, Revital; Roskin, Joel; Bialik, Or; Golan, Arik; Sivan, Dorit

    2016-04-01

    Sea-level fluctuations are a dominant and dynamic mechanism that control coastal environmental through time. This is especially the case for the successive regressions and transgressions over the last interglacial cycle, which have shaped the deposition, preservation and erosion patterns of unconsolidated sediments currently submerged on continental shelves. The current study focuses on an integrated high-resolution marine and terrestrial litho-stratigraphic and geophysical framework of the north-central Mediterranean coastal zone of Israel. The interpretation enabled the reconstruction of the coastal evolution over the last ˜130 ka. A multi-disciplinary approach was applied by compiling existing elevation raster grids, bathymetric charts, detailed lithological borehole data-sets, a dense 110 km long sub-bottom geophysical survey and seven continuous boreholes sediment records. Based on seismic stratigraphic analysis, observed geometries, and reflective appearances, six bounding surfaces and seven seismic units were identified and characterized. Meanwhile, the chronostratigraphy of the terrestrial side was constructed through integration of magnetic susceptibility, sedimentological and geochemical analysis with 17 new OSL ages. The seismic units were correlated with the available terrestrial borehole data and then associated to the retrieved terrestrial chronostratigraphy to produce a 4D reconstruction model of the paleo-landscape. The entire unconsolidated sequence overlies a calcareous aeolianite (locally named Kurkar unit) dated from ˜131 - ˜104 ka, which represents the top of the last interglacial cycle dune sediments. The lower unconsolidated unit consists of a red silty loam dated to ˜71 ka. This Red-Paleosol unit is overlaid by a dark brown clayey silty loam This Brown-Paleosol unit dates to ˜58 - ˜36 ka and is overlaid by a dark silty clay wetland deposit dated to ˜21 - ˜10 ka. The wetland unit is topped by a quartz sand dated to ˜6.6 - 0.1 ka

  10. On cold spells in North America and storminess in western Europe

    NASA Astrophysics Data System (ADS)

    Messori, Gabriele; Caballero, Rodrigo; Gaetani, Marco

    2016-06-01

    We discuss the dynamical and statistical links between cold extremes over eastern North America and storminess over western Europe, with a focus on the midlatitude jet stream, the North Atlantic Oscillation (NAO) and the Pacific-North American Pattern (PNA). The analysis is performed on the European Centre for Medium-Range Weather Forecasts 20th Century Reanalysis. The large-scale circulation associated with the cold spells corresponds to advection of cold air from the Arctic region into North America and to a very zonal and intense North Atlantic jet, shifted persistently south of its climatological location. These features of the Atlantic jet are conducive to destructive windstorms and intense precipitation over a large part of southern and continental Europe and the British Isles. The cold spells are preceded by a negative NAO and followed by a positive PNA; however, we interpret the associated circulation anomalies as being distinct from these standard modes of climate variability.

  11. Nutrient control of phytoplankton photosynthesis in the western North Atlantic

    NASA Technical Reports Server (NTRS)

    Platt, Trevor; Sathyendranath, Shubha; Ulloa, Osvaldo; Harrison, William G.; Hoepffner, Nicolas; Goes, Joaquim

    1992-01-01

    Results from several years of oceanographic cruises are reported which show that the parameters of the photosynthesis-light curve of the flora of the North Sargasso Sea are remarkably constant in magnitude, except during the spring phytoplankton bloom when their magnitudes are noticeably higher. These results are interpreted as providing direct evidence for nutrient control of photosynthesis in the open ocean. The findings also reinforce the plausibility of using biogeochemical provinces to partition the ocean into manageable units for basin- or global-scale analysis. They show that seasonal changes in critical parameter should not be overlooked if robust carbon budgets are to be constructed, and illustrate the value of attacking the parameters that control the key fluxes, rather than the fluxes themselves, when investigating the ocean carbon cycle.

  12. Lead isotopes in the western North Atlantic: Transient tracers of pollutant lead inputs

    SciTech Connect

    Veron, A.J. |; Church, T.M.; Flegal, A.R.

    1998-08-01

    In the early 1980s, Patterson and colleagues demonstrated that most lead in oceanic surface waters had an anthropogenic origin. Their discovery occurred during the phasing out of leaded gasoline in North America initiated in the previous decade. The corresponding decrease in anthropogenic lead emissions, verified by Pb/{sup 210}Pb ratios, accounted for the systematic decline in lead concentrations in surface waters of the western Sargasso Sea. Subsequent changes in anthropogenic lead inputs to the western Sargasso Sea surface waters have been documented by measurements of lead concentrations, isotopic compositions ({sup 206}Pb/{sup 207}Pb, {sup 208}Pb/{sup 206}Pb), and Pb/{sup 210}Pb ratios in precipitation and seawater for the period of 1981 to 1994. These data indicate the easterly trade winds are now the primary source of atmospheric lead in Bermuda, and they confirm that the decline of lead concentrations in the North Atlantic is associated with the phasing out of leaded gasoline in North America and western Europe over the past decade. Moreover, temporal variations in the relative contribution of industrial lead inputs from the two sides of the North Atlantic over that period can be quantified based on differences in their isotopic composition. The transient character of those isotopic signatures also allows calculations of pollutant lead penetration rates into the mixed layer and upper thermocline of the western Sargasso Sea.

  13. A new species of Anthocoris (Hemiptera: Heteroptera: Anthocoridae) from western North America

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Anthocoris aquilivenis Lewis, n. sp. is described from the mountainous areas of western North America. It is compared to the Nearctic species Anthocoris tomentosus Péricart and Anthocoris antevolens White, and to Anthocoris sibiricus Reuter, a related Palearctic species. Illustrations are provided o...

  14. CHALLENGES TO SUSTAINING DIADROMOUS FISHES THROUGH 2100: LESSONS LEARNED FROM WESTERN NORTH AMERICA

    EPA Science Inventory

    An evaluation of the history of efforts to reverse the long-term decline of Pacific salmon in western North America provides instructive policy lessons for the potential recovery of diadromous fishes throughout the world. From California to southern British Columbia, wild runs o...

  15. Whales, Dolphins, and Porpoises of the Western North Atlantic: A Guide to Their Identification.

    ERIC Educational Resources Information Center

    Leatherwood, Stephen; And Others

    This field guide is designed to permit observers to identify the cetaceans (whales, dolphins, and porpoises) they see in western North Atlantic, including the Caribbean Sea, the Gulf of Mexico, and the coastal waters of the United States and Canada. The animals described are not grouped by scientific relationships but by similarities in appearance…

  16. USDA-ARS Poisonous Plant Research Laboratory: History and current research on western North American rangelands

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Poisonous plants on western North American rangelands have historically been troublesome to livestock producers. Research on toxic plants was initiated by U.S. Department of Agriculture in the late 1890’s to solve problems for the livestock industry. The USDA-ARS Poisonous Plant Research Laborator...

  17. Quinoa cultivation in western North America: lessons learned and the path forward

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Quinoa (Chenopodium quinoa Willd) is a relatively new crop to farmers in North America; however recent interest in domestic cultivation of quinoa has skyrocketed due to a rapid, worldwide increase in demand for this nutritious and delicious Andean crop. Researchers at five western U.S. universities ...

  18. The Current State of European Studies in North America and of Scholarly Publishing in Western Europe.

    ERIC Educational Resources Information Center

    Hacken, Richard

    1998-01-01

    Relates how scholarly publishing in Western Europe feeds into North America. Discusses globalization, regionalism, and particularism; new models and research methodology; Biblio-Darwinism (survival of the fittest publishing languages) and the language of the imprint; differing academic infrastructures of Europe; booming scholarly-title production;…

  19. CHALLENGES TO SUSTAINING DIADROMOUS FISHES THROUGH 2100: LESSONS LEARNED FROM WESTERN NORTH AMERICA

    EPA Science Inventory

    An evaluation of the history of efforts to reverse the long-term decline of Pacific Salmon in western North America provides instructive policy lessons for the potential recovery of diadromous fishes throughout the world. From California to southern British Columbia, wild runs of...

  20. A new species of Empruthotrema (Monogenea: Monocotylidae) from Pteromylaeus bovinus (Myliobatidae) from the Western Mediterranean.

    PubMed

    Hernández-Orts, Jesús S; Ahuir-Baraja, Ana E; Raga, Juan A; Montero, Francisco E

    2010-12-01

    Empruthotrema chisholmae n. sp. is described from specimens recovered from a bull ray Pteromylaeus bovinus (Geoffroy Saint-Hilaire, 1817) at the Oceanogràfic Aquarium in Valencia, Spain. The bull ray was caught in the Spanish Mediterranean (Puerto de Mazarrón, Murcia). The new species resembles 4 others of the same genus ( Empruthotrema dasyatidis Whittington and Kearn, 1992, Empruthotrema kearni Whittington, 1990, Empruthotrema stenophallus Chisholm and Whittington, 2005, and Empruthotrema tasmaniensis Chisholm and Whittington, 1999) in having a haptor with 13 marginal loculi, the posteriormost loculus single and medial. The new species can be distinguished from these other species of the genus by the morphology of the sclerotized male copulatory organ, which is the shortest described. The new species also differs from the other species by the following combination of features: haptor with 13 marginal loculi, the presence of eyespots, the absence of an accessory piece associated with the male copulatory organ, and a long egg appendage (more than 150 µm). Empruthotrema chisholmae is the first species of the genus reported from the Mediterranean. PMID:21158614

  1. Hydro-geochemical aspects of Mediterranean temporary ponds in western Crete.

    PubMed

    Stamati, Fotini; Nikolaidis, Nikolaos; Dimitriou, Elias; Koussouris, Theodore

    2008-01-01

    The hydrologic and geochemical conditions that prevail in Mediterranean temporary ponds (MTPs), create a unique environment for many rare and endangered species. Mediterranean temporary ponds are habitats of high ecological value, which are vulnerable to imminent climatic changes, as well as to human activities. This article examines the hydrology and the nitrogen and phosphorous geochemical cycles of four MTPs in Crete. Field and laboratory studies provided the necessary information for the development of a conceptual understanding of the hydrologic and biogeochemical processes that affect the fate of nitrogen and phosphorous in these MTPs. Their hydrology was driven by deposition, infiltration, and evaporation. The hydroperiod of the ponds varied between 40 and 160 d. Mineralization and nutrient release capacity experiments illustrated the significant role that MTP sediments played in enhancing the geochemistry of the aqueous phase. Such ecosystem functions (i.e., mineralization, nutrient release) exhibited high variability among MTPs necessitating site-specific studies with immediate implications to management. It is very important to understand the local hydrogeochemical and climatic conditions to ensure appropriate environmental measures for their management and conservation.

  2. Possible relationship between East Asian summer monsoon and western North Pacific tropical cyclone genesis frequency

    NASA Astrophysics Data System (ADS)

    Choi, Ki-Seon; Cha, Yumi; Kim, Hae-Dong; Kang, Sung-Dae

    2016-04-01

    In the present study, the fact that strong positive correlations have existed between East Asian summer monsoons (EASMs) and western North Pacific tropical cyclone (TC) genesis frequency over the last 37 years was found. To figure out the cause of these correlations, 7 years (positive East Asian summer monsoon index (EASMI) phase) that have the highest values and 7 years (negative EASMI phase) that have the lowest values in the normalized EASM index were selected and the differences in averages between the two phases were analyzed. In the positive EASMI phase, TCs mainly occurred in the northwestern waters of the tropical and subtropical western North Pacific and showed a tendency to move from the far eastern waters of the Philippines, pass the East China Sea, and move northward toward Korea and Japan. On the 500 hPa streamline, whereas anomalous anticyclones developed in the East Asia middle-latitude region, anomalous cyclones developed in the tropical and subtropical western North Pacific. Therefore, in this phase, whereas EASMs were weakened, western North Pacific summer monsoons (WNPSMs) were strengthened so that some more TCs could occur. In addition, in the case of the East China Sea and the southern waters of Japan located between the two anomalous pressure systems, TCs could move some more toward the East Asia middle-latitude region in this phase. According to an analysis of the 850 hPa relative vorticity, negative anomalies were strengthened in the East Asia middle-latitude region while positive anomalies were strengthened in the region south to 25 N. Therefore, in the positive EASMI phase, whereas EASMs were weakened, WNPSMs were strengthened so that some more TCs could occur. According to an analysis of the 850 and 200 hPa horizontal divergence, whereas anomalous downward flows were strengthened in the East Asia middle-latitude region, anomalous upward flows were strengthened in the tropical and subtropical western North Pacific. According to an analysis

  3. Evolution of the Arctic-North Atlantic and the Western Tethys

    SciTech Connect

    Ziegler, P.A. )

    1988-01-01

    This volume provides an overview of the late Paleozoic to recent geological evolution of the continents and shelves bordering the North Atlantic Ocean, the Norwegian-Greenland Sea, the Arctic Ocean, and the Mediterranean Sea. The evolution of these seas has been the subject of many studies and compilations, which discuss the evolution of oceanic basins on the basis of their magnetic sea-floor anomalies. The volume presented combines this information with geological data from the adjacent shelf and onshore areas. It retraces the evolution of sedimentary basins developed during the rifting phases that preceded the opening of these oceans and highlights the scope of the associated intra-plate phenomena. The author presents a reconstruction of the late Paleozoic and early Mesozoic development of Europe, northernmost Africa and northeastern North America-Greenland and discusses the different orogenic cycles that accompanied the stepwise assembly of Pangea and the early rifting phases heralding its break-up.

  4. REV-ERB-ALPHA circadian gene variant associates with obesity in two independent populations: Mediterranean and North American

    PubMed Central

    Garaulet, Marta; Smith, Caren E.; Gomez-Abellán, Purificación; Ordovás-Montañés, María; Lee, Yu-Chi; Parnell, Laurence D.; Arnett, Donna K.; Ordovás, José M.

    2014-01-01

    Scope Despite the solid connection between REV-ERB and obesity, the information about whether genetic variations at this locus may be associated with obesity traits is scarce. Therefore our objective was to study the association between REV-ERB-ALPHA1 rs2314339 and obesity in two independent populations. Methods and results Participants were 2214 subjects from Spanish Mediterranean (n = 1404) and North American (n = 810) populations. Anthropometric, biochemical, dietary, and genotype analyses were performed. We found novel associations between the REV-ERB-ALPHA1 rs2314339 genotype and obesity in two independent populations: in Spanish Mediterranean and North American groups, the frequency of the minor-allele-carriers (AA+ AG) was significantly lower in the “abdominally obese” group than in those of the “nonabdominally obese” group (p < 0.05). Minor allele carriers had lower probability of abdominal obesity than noncarriers, and the effect was of similar magnitude for both populations (OR ≈ 1.50). There were consistent associations between REV-ERB-ALPHA1 genotype and obesity-related traits (p < 0.05). Energy intake was not significantly associated with REV-ERB-ALPHA1 rs2314339. However, physical activity significantly differed by genotype. A significant interaction between the REV-ERB-ALPHA1 variant and monounsaturated-fatty-acids (MUFA) intake for obesity was also detected in the Mediterranean population. Conclusion This new discovery highlights the importance of REV-ERB-ALPHA1 in obesity and provides evidence for the connection between our biological clock and obesity-related traits. PMID:24173768

  5. The food of Near East, North West and Western African regions.

    PubMed

    Burlingame, Barbara

    2003-01-01

    Among the countries that can be classified as Near East Africa, North West Africa, and Western Africa, there is a great diversity of foods and dietary patterns. Prevalence of undernourishment as defined by FAO using dietary energy supply data, varies dramatically among these countries, with Tunisia in the lowest prevalence category (<2.5%), and Sierra Leone in the highest prevalence category (>35%). Throughout the 1960's, the dietary energy supply of North West African and Western African countries was similar. However, since the 1970s a great and consistent improvement has been seen in North and North West African countries. Both the proportion and number of undernourished in North Africa is now very similar to that of North America. Oil use, energy from fat, and protein from plant versus animal sources account for a large part of the food pattern differences between countries in these regions. Using Tunisia and Sierra Leone as examples again, dietary diversity as measured by the percentage of energy from foods other than starchy staples, is about 50% in the former, while in the latter, it is only 36%. Fatty fruits such as olives, cocoa and palm fruit have a special role in both the diet and the economies of the region. PMID:14505995

  6. The food of Near East, North West and Western African regions.

    PubMed

    Burlingame, Barbara

    2003-01-01

    Among the countries that can be classified as Near East Africa, North West Africa, and Western Africa, there is a great diversity of foods and dietary patterns. Prevalence of undernourishment as defined by FAO using dietary energy supply data, varies dramatically among these countries, with Tunisia in the lowest prevalence category (<2.5%), and Sierra Leone in the highest prevalence category (>35%). Throughout the 1960's, the dietary energy supply of North West African and Western African countries was similar. However, since the 1970s a great and consistent improvement has been seen in North and North West African countries. Both the proportion and number of undernourished in North Africa is now very similar to that of North America. Oil use, energy from fat, and protein from plant versus animal sources account for a large part of the food pattern differences between countries in these regions. Using Tunisia and Sierra Leone as examples again, dietary diversity as measured by the percentage of energy from foods other than starchy staples, is about 50% in the former, while in the latter, it is only 36%. Fatty fruits such as olives, cocoa and palm fruit have a special role in both the diet and the economies of the region.

  7. Predicting Grizzly Bear Density in Western North America

    PubMed Central

    Mowat, Garth; Heard, Douglas C.; Schwarz, Carl J.

    2013-01-01

    Conservation of grizzly bears (Ursus arctos) is often controversial and the disagreement often is focused on the estimates of density used to calculate allowable kill. Many recent estimates of grizzly bear density are now available but field-based estimates will never be available for more than a small portion of hunted populations. Current methods of predicting density in areas of management interest are subjective and untested. Objective methods have been proposed, but these statistical models are so dependent on results from individual study areas that the models do not generalize well. We built regression models to relate grizzly bear density to ultimate measures of ecosystem productivity and mortality for interior and coastal ecosystems in North America. We used 90 measures of grizzly bear density in interior ecosystems, of which 14 were currently known to be unoccupied by grizzly bears. In coastal areas, we used 17 measures of density including 2 unoccupied areas. Our best model for coastal areas included a negative relationship with tree cover and positive relationships with the proportion of salmon in the diet and topographic ruggedness, which was correlated with precipitation. Our best interior model included 3 variables that indexed terrestrial productivity, 1 describing vegetation cover, 2 indices of human use of the landscape and, an index of topographic ruggedness. We used our models to predict current population sizes across Canada and present these as alternatives to current population estimates. Our models predict fewer grizzly bears in British Columbia but more bears in Canada than in the latest status review. These predictions can be used to assess population status, set limits for total human-caused mortality, and for conservation planning, but because our predictions are static, they cannot be used to assess population trend. PMID:24367552

  8. Predicting grizzly bear density in western North America.

    PubMed

    Mowat, Garth; Heard, Douglas C; Schwarz, Carl J

    2013-01-01

    Conservation of grizzly bears (Ursus arctos) is often controversial and the disagreement often is focused on the estimates of density used to calculate allowable kill. Many recent estimates of grizzly bear density are now available but field-based estimates will never be available for more than a small portion of hunted populations. Current methods of predicting density in areas of management interest are subjective and untested. Objective methods have been proposed, but these statistical models are so dependent on results from individual study areas that the models do not generalize well. We built regression models to relate grizzly bear density to ultimate measures of ecosystem productivity and mortality for interior and coastal ecosystems in North America. We used 90 measures of grizzly bear density in interior ecosystems, of which 14 were currently known to be unoccupied by grizzly bears. In coastal areas, we used 17 measures of density including 2 unoccupied areas. Our best model for coastal areas included a negative relationship with tree cover and positive relationships with the proportion of salmon in the diet and topographic ruggedness, which was correlated with precipitation. Our best interior model included 3 variables that indexed terrestrial productivity, 1 describing vegetation cover, 2 indices of human use of the landscape and, an index of topographic ruggedness. We used our models to predict current population sizes across Canada and present these as alternatives to current population estimates. Our models predict fewer grizzly bears in British Columbia but more bears in Canada than in the latest status review. These predictions can be used to assess population status, set limits for total human-caused mortality, and for conservation planning, but because our predictions are static, they cannot be used to assess population trend. PMID:24367552

  9. Predicting grizzly bear density in western North America.

    PubMed

    Mowat, Garth; Heard, Douglas C; Schwarz, Carl J

    2013-01-01

    Conservation of grizzly bears (Ursus arctos) is often controversial and the disagreement often is focused on the estimates of density used to calculate allowable kill. Many recent estimates of grizzly bear density are now available but field-based estimates will never be available for more than a small portion of hunted populations. Current methods of predicting density in areas of management interest are subjective and untested. Objective methods have been proposed, but these statistical models are so dependent on results from individual study areas that the models do not generalize well. We built regression models to relate grizzly bear density to ultimate measures of ecosystem productivity and mortality for interior and coastal ecosystems in North America. We used 90 measures of grizzly bear density in interior ecosystems, of which 14 were currently known to be unoccupied by grizzly bears. In coastal areas, we used 17 measures of density including 2 unoccupied areas. Our best model for coastal areas included a negative relationship with tree cover and positive relationships with the proportion of salmon in the diet and topographic ruggedness, which was correlated with precipitation. Our best interior model included 3 variables that indexed terrestrial productivity, 1 describing vegetation cover, 2 indices of human use of the landscape and, an index of topographic ruggedness. We used our models to predict current population sizes across Canada and present these as alternatives to current population estimates. Our models predict fewer grizzly bears in British Columbia but more bears in Canada than in the latest status review. These predictions can be used to assess population status, set limits for total human-caused mortality, and for conservation planning, but because our predictions are static, they cannot be used to assess population trend.

  10. Digenean species diversity in teleost fishes from the Gulf of Gabes, Tunisia (Western Mediterranean)

    PubMed Central

    Derbel, H.; Châari, M.; Neifar, L.

    2012-01-01

    This study is the first attempt to survey the diversity of fish digeneans in the Gulf of Gabes (southern coast of Tunisia). A total of 779 fishes belonging to 32 species were sampled. 53 species of Digenea belonging to 15 families were recorded. Among these species, 24 are reported for the first time from the coast of Tunisia. We report one new host record, Lecithochirium sp. from Sardinella aurita. The Hemiuridae is the dominant family. A host-parasite list is presented with the information on the prevalence, abundance and mean intensity of each species collected. The diversity of Digenea is compared with other localities in the Mediterranean Sea and the northern east of Tunisia. The Gulf of Gabes shows the lowest diversity linked to the anthropogenic activities and impact of exotic species. The use of Digenea as indicators of the state of the ecosystem is discussed. PMID:22550623

  11. Gastrointestinal helminths of Cuvier's beaked whales, Ziphius cavirostris, from the western Mediterranean.

    PubMed

    Fernández, Mercedes; Aznar, F Javier; Montero, Francisco E; Georgiev, Boyko B; Raga, Juan A

    2004-04-01

    We examined the gastrointestinal helminth fauna of 2 Cuvier's beaked whales, Ziphius cavirostris, stranded on the Spanish Mediterranean coast. Information regarding intestinal parasites of this species is provided for the first time. Six helminth taxa were identified. Thirty type II larvae of the nematode Anisakis sp. were found in the stomach and the intestine of both hosts; 2 type I larvae of Anisakis sp. were found in the intestine of 1 host. One juvenile of the acanthocephalan Bolbosoma vasculosum was found in the intestine; the metacestode Scolex pleuronectis was found mainly in the terminal colon and the anal crypts of both hosts; adult cestodes of Tetrabothrius sp., which may represent a new species, were collected from the duodenum of 1 host. Composition of the intestinal parasitic community is similar to that of other oceanic cetaceans, which mostly include species of Bolbosoma and tetrabothriids (Cestoda).

  12. Severe rainfall events over the western Mediterranean Sea: A case study

    NASA Astrophysics Data System (ADS)

    Riesco Martín, Jesús; Mora García, Manuel; de Pablo Dávila, Fernando; Rivas Soriano, Luis

    2013-06-01

    A study of severe rainfall (≥ 100 mm in 24 h) over the Spanish provinces of Malaga, Granada y Almeria (close to the Alboran Sea, the westernmost part of the Mediterranean Sea) has been performed using 5 years (2006-2010) of data. The episodes of heavy rainfall were classified using the moisture flux at the 850 hPa pressure level and the lifted index. This gave three types, associated with situations of intense moisture flux and little static instability, moderate moisture flux and static instability, and moderate moisture flux and strong static instability. Representative cases of each type were analyzed, and it was found that both non-convective (41% of cases) and convective (59% of cases) systems caused the episodes of severe precipitation considered in this study. The convective structures included isolated and persistent convective systems, multicellular convective systems, and mesoscale convective systems.

  13. The Role of Soil Water and Land Feedbacks in Decadal Drought in Western North America

    NASA Astrophysics Data System (ADS)

    Langford, S.; Chikamoto, Y.; Noone, D. C.

    2013-12-01

    Western North America is susceptible to severe impacts of megadroughts, as evidenced by tree-core or lake sediment records. Future predictions suggest that this region will become more arid, with further consequences for water resources. Understanding the mechanisms of drought variability and persistence in western North America is critical for the eventual development of effective forecasting methods. The ocean is expected to be the main source of decadal memory in the system as the atmosphere varies on a much shorter timescale. The ocean's role in driving the low-frequency variability of the system is potentially predictable. However, low-frequency precipitation anomalies in western North America can occur in the absence of ocean feedbacks. Sea surface temperature anomalies in the north Pacific Ocean only account for around 20 per cent of the low-frequency winter precipitation in California in the CMIP5 historical runs. This is not sufficient to use the skill of global coupled models in predicting ocean conditions ahead of time to successfully forecast the possibility of long-term drought in western North America. Megadroughts therefore may be generated by unpredictable atmospheric noise, or persisted by other sources of low-frequency variability such as land processes and feedbacks. Snowpack in western North America is a crucial water resource for the surrounding communities, storing the winter precipitation for use later in the year. Likewise, soil moisture integrates the precipitation signal; the time scale depends on the depth and characteristics of the soil. Water storage and related variables are more predictable on longer timescales than precipitation, as measured by anomaly correlation for hindcasts compared to a 'perfect model' control run with CESM1.0.3. The importance of antecedent land conditions in persisting megadroughts in western North America is explored with ensemble simulations of CESM1.0.3, where the atmosphere is perturbed at the initiation

  14. Early rise and contractional reactivation of distal salt diapirs in the western Mediterranean : a new two-step scenario

    NASA Astrophysics Data System (ADS)

    Gaullier, Virginie; Vendeville, Bruno; Sage, Françoise; Droz, Laurence

    2014-05-01

    Some of the world's most spectacular salt structures are located along salt-bearing continental margins along which large amount of sediments have prograded seaward. The structural style includes extensional, diapiric and contractional features, which implies that, there, both salt and its sediment overburden have been subjected to significant amounts of along-slope displacement. Contractional structures are typically found along the lower slope, whereas extensional structures are located along the upper slope and on the shelf. Around 6 Ma ago, the Mediterranean basin underwent spectacular paleo-environmental changes during the Messinian Salinity Crisis: the margins were deeply eroded in response to a sea-level drop of more than 1500 m, and thick evaporitic series were deposited in the deep basins. The Messinian mobile salt is therefore post-rift since the opening of the Liguro-Provençal basin formed during the Oligo-Aquitanian age (the main tilting of the margins due to the rifting had already happened and the base of the salt layer was often sub-horizontal or even landward-dipping). Plio-Quaternary tectonics in the deep western Mediterranean is dominated by huge thin-skinned salt tectonics with gravity spreading and/or gliding above the Messinian décollement. It is typically characterized by proximal extension, mid-slope translation, and distal shortening. The distal region of the western Mediterranean, especially in the Gulf of Lions, comprises circular or elongate diapirs, whose initiation was traditionally attributed to combined shortening and sediment loading. Nevertheless, new seismic data and re-interpretation of older ones recently showed that salt tectonics there started very early in the deepest parts of the basin, immediately after deposition of the mobile salt, as is attested by lateral thickness changes and internal angular unconformities within the Messinian Upper Unit, while the Upper Unit in the upslope region remained isopach. This means that

  15. Performance of salmon fishery portfolios across western North America

    PubMed Central

    Griffiths, Jennifer R; Schindler, Daniel E; Armstrong, Jonathan B; Scheuerell, Mark D; Whited, Diane C; Clark, Robert A; Hilborn, Ray; Holt, Carrie A; Lindley, Steven T; Stanford, Jack A; Volk, Eric C

    2014-01-01

    Quantifying the variability in the delivery of ecosystem services across the landscape can be used to set appropriate management targets, evaluate resilience and target conservation efforts. Ecosystem functions and services may exhibit portfolio-type dynamics, whereby diversity within lower levels promotes stability at more aggregated levels. Portfolio theory provides a framework to characterize the relative performance among ecosystems and the processes that drive differences in performance. We assessed Pacific salmon Oncorhynchus spp. portfolio performance across their native latitudinal range focusing on the reliability of salmon returns as a metric with which to assess the function of salmon ecosystems and their services to humans. We used the Sharpe ratio (e.g. the size of the total salmon return to the portfolio relative to its variability (risk)) to evaluate the performance of Chinook and sockeye salmon portfolios across the west coast of North America. We evaluated the effects on portfolio performance from the variance of and covariance among salmon returns within each portfolio, and the association between portfolio performance and watershed attributes. We found a positive latitudinal trend in the risk-adjusted performance of Chinook and sockeye salmon portfolios that also correlated negatively with anthropogenic impact on watersheds (e.g. dams and land-use change). High-latitude Chinook salmon portfolios were on average 2·5 times more reliable, and their portfolio risk was mainly due to low variance in the individual assets. Sockeye salmon portfolios were also more reliable at higher latitudes, but sources of risk varied among the highest performing portfolios. Synthesis and applications. Portfolio theory provides a straightforward method for characterizing the resilience of salmon ecosystems and their services. Natural variability in portfolio performance among undeveloped watersheds provides a benchmark for restoration efforts. Locally and regionally

  16. Simulations of Western North American Hydroclimate during the Little Ice Age and Medieval Climate Anomaly

    NASA Astrophysics Data System (ADS)

    Simon, S. M.; Mann, M. E.; Steinman, B. A.; Feng, S.; Zhang, Y.; Miller, S. K.

    2013-12-01

    Despite the immense impact that large, modern North American droughts, such as those of the 1930s and 1950s, have had on economic, social, aquacultural, and agricultural systems, they are smaller in duration and magnitude than the multidecadal megadroughts that affected North America, in particular the western United States, during the Medieval Climate Anomaly (MCA, ~ 900-1300 AD) and the Little Age (LIA, ~1450-1850 AD). Although various proxy records have been used to reconstruct the timing of these MCA and LIA megadroughts in the western United States, there still exists great uncertainty in the magnitude and spatial coherence of such droughts in the Pacific Northwest region, especially on decadal to centennial timescales. This uncertainty motivates the following study to establish a causal link between the climate forcing that induced these megadroughts and the spatiotemporal response of regional North American hydroclimates to this forcing. This study seeks to establish a better understanding of the influence of tropical Pacific and North Atlantic SSTs on North American drought during the MCA and LIA. We force NCAR's Community Atmospheric Model version 5.1.1 (CAM 5) with prescribed proxy-reconstructed tropical Pacific and North Atlantic SST anomalies from the MCA and LIA, in order to investigate the influence that these SST anomalies had on the spatiotemporal patterns of drought in North America. To isolate the effects of individual ocean basin SSTs on the North American climate system, the model experiments use a variety of SST permutations in the tropical Pacific and North Atlantic basin as external forcing. In order to quantify the spatiotemporal response of the North American climate system to these SST forcing permutations, temperature and precipitation data derived from the MCA and LIA model experiments are compared to lake sediment isotope and tree ring-based hydroclimate reconstructions from the Pacific Northwest. The spatiotemporal temperature and

  17. Diversity of Bradyrhizobium strains nodulating Lupinus micranthus on both sides of the Western Mediterranean: Algeria and Spain.

    PubMed

    Bourebaba, Yasmina; Durán, David; Boulila, Farida; Ahnia, Hadjira; Boulila, Abdelghani; Temprano, Francisco; Palacios, José M; Imperial, Juan; Ruiz-Argüeso, Tomás; Rey, Luis

    2016-06-01

    Lupinus micranthus is a lupine distributed in the Mediterranean basin whose nitrogen fixing symbiosis has not been described in detail. In this study, 101 slow-growing nodule isolates were obtained from L. micranthus thriving in soils on both sides of the Western Mediterranean. The diversity of the isolates, 60 from Algeria and 41 from Spain, was addressed by multilocus sequence analysis of housekeeping genes (16S rRNA, atpD, glnII and recA) and one symbiotic gene (nodC). Using genomic fingerprints from BOX elements, 37 different profiles were obtained (22 from Algeria and 15 from Spain). Phylogenetic analysis based on 16S rRNA and concatenated atpD, glnII and recA sequences of a representative isolate of each BOX profile displayed a homogeneous distribution of profiles in six different phylogenetic clusters. All isolates were taxonomically ascribed to the genus Bradyrhizobium. Three clusters comprising 24, 6, and 4 isolates, respectively, accounted for most of the profiles. The largest cluster was close to the Bradyrhizobium canariense lineage, while the other two were related to B. cytisi/B. rifense. The three remaining clusters included only one isolate each, and were close to B. canariense, B. japonicum and B. elkanii species, respectively. In contrast, phylogenetic clustering of BOX profiles based on nodC sequences yielded only two phylogenetic groups. One of them included all the profiles except one, and belonged to symbiovar genistearum. The remaining profile, constituted by a strain related to B. elkanii, was not related to any well-defined symbiotic lineage, and may constitute both a new symbiovar and a new genospecies. PMID:27236566

  18. Revealing polychaetes invasion patterns: Identification, reproduction and potential risks of the Korean ragworm, Perinereis linea (Treadwell), in the Western Mediterranean

    NASA Astrophysics Data System (ADS)

    Arias, Andrés; Richter, Alexandra; Anadón, Nuria; Glasby, Christopher J.

    2013-10-01

    An established population of the polychaetous annelid Perinereis linea (Treadwell) is reported for the first time outside its native distribution range (NW Pacific). This exotic worm has reached the Western Mediterranean (Mar Menor lagoon) via importing live fishing-bait as it is commonly used by anglers in Mar Menor lagoon, an area largely used for recreational fishing. To avoid confusion with other related species, and because the scientific name has been in synonymy for many years, P. linea is redescribed and illustrated. We focus on the reproductive biology and ecology of P. linea to help to understand its introduction, naturalization and spread along this coastal lagoon. Comparison between the Mediterranean population with a native population from South Korea revealed that the species exhibits a great reproductive plasticity and adaptability, which depends on the environmental conditions. Perinereis linea can reproduce after acquiring the epitokous form or prior to complete epitokal modification. In the Mar Menor lagoon population females release eggs asynchronically without completing epitokal modifications. However, under particular laboratory conditions females produce eggs synchronically and release them after complete epitokal transformations. Fertilization can occur internally in the female coelom, and females release zygotes and larvae through openings in their body walls; they are then incubated in gelatinous masses attached to the female parapodia. The sperm morphology is of the ent-aquasperm type. The eggs and larvae are attacked by symbiotic ciliate protozoa that feed on their yolk reserves. These foreign ciliates may act as carriers of disease in native beachworms and constitute an important risk for the ecosystem health. Finally, we provide recommendations on the prevention of the adverse effects that this exotic ragworm can cause in receiving ecosystems.

  19. Late Miocene sedimentary architecture of the Ebro Continental Margin (Western Mediterranean): Implications to the Messinian Salinity Crisis

    NASA Astrophysics Data System (ADS)

    Cameselle, Alejandra L.; Urgeles, Roger; De Mol, Ben; Camerlenghi, Angelo

    2014-05-01

    The Messinian Salinity Crisis (MSC) resulted from a significant multi-phase drop and subsequent reflooding of the Mediterranean Sea during the Late Miocene. In a relatively short time span (5.96 to 5.33 Ma), partial desiccation of the basin and consequent subaerial exposure of the continental margins resulted in widespread erosion of continental shelves and slopes and regressive erosion along major fluvial valleys. Using 3D seismic reflection data from the Ebro Margin (Western Mediterranean), we provide new insights into the origin of the Messinian Erosional Surface (MES) and timing of the capture of the subaerial Ebro Basin. The observed sedimentary architecture of the Ebro Continental Margin indicates a sedimentary-active continental slope and delta progradation during Middle-Late Miocene, in a normal regressive context associated to a pre-Messinian proto-Ebro River. Configuration of the clinoforms below the MES suggests that deltaic sediments of the Messinian Paleo-Ebro River deposited during the Tortonian and initial Messinian sea-level drawdown. The MES formed at the top of the Tortonian Highstand, where a fluvial network was deeply carved, and in the topset region of the Messinian Falling Stage Systems Tract, where minor erosion occurred. The patterns of Messinian erosion and sedimentation produced a MES with a step-like profile. Significant Miocene progradation and the mature development attained by the Messinian Ebro River network during the MSC indicate that capture of the Ebro Basin occurred prior to the MSC. Fluvial deposits are outstandingly preserved on the main valleys of the MES indicating that re-flooding of the margin was extremely rapid. Therefore, the step-like profile of the MES was created during the latest stages of the main Messinian sea-level drawdown and lowstand.

  20. Late Miocene sedimentary architecture of the Ebro Continental Margin (Western Mediterranean): implications to the Messinian Salinity Crisis

    NASA Astrophysics Data System (ADS)

    Cameselle, Alejandra L.; Urgeles, Roger; De Mol, Ben; Camerlenghi, Angelo; Canning, Jason C.

    2014-03-01

    The Messinian Salinity Crisis (MSC) resulted from a significant multi-phase drop and subsequent reflooding of the Mediterranean Sea from 5.96 to 5.33 Ma. Well-developed drainage networks, characterized by step-like profiles and abrasion platforms, are associated to this event. The Ebro Continental Margin (Western Mediterranean) presents an additional complexity since the capture of the drainage of the adjacent subaerial Ebro Basin took place sometime prior to the Messinian stage. Using 3D seismic reflection data, this work provides new insights into the origin of the step-like profile of the Messinian erosional surface (MES) and timing of the capture of the subaerial Ebro Basin. The results obtained indicate a sedimentary-active continental slope and delta progradation during Middle-Late Miocene, in a normal regressive context associated to a pre-Messinian proto-Ebro River. The mature development attained by the Messinian Ebro River network during the MSC corroborates that the capture of the Ebro Basin occurred prior to the MSC. The configuration of the clinoforms below the MES suggests that deltaic sediments of the Messinian Paleo-Ebro River deposited during the Tortonian and initial Messinian sea-level drawdown. The MES formed at the top of the Tortonian Highstand, where a fluvial network was deeply carved, and in the topset region of the Messinian Falling Stage Systems Tract, where minor erosion occurred. Fluvial deposits are outstandingly preserved on the main valleys of the MES. Therefore, the step-like profile of the MES was not created during Zanclean inundation, but during the latest stages of the main Messinian sea-level fall and lowstand.

  1. Dyke belt in North Western margin of Siberian platform

    NASA Astrophysics Data System (ADS)

    Ryabov, Victor

    2015-04-01

    The Early Triassic dyke swarm belt is strengthening at about 500 km (50-60 km width) along the northern margin of Siberian platform. Its locations is limited from the north by rift structure of the Yenisei-Khatanga trough, and from the south by Kystyktah-Ayan-Ambardah uprise. From west to east dyke belt is crossing Norilsk, Kamensky and Maimecha-Kotuiskaya province. In this direction the composition of dykes changing from basic rthrough alkali-basic to alkali-ultramafic varieties. The sickness of dykes varies from 0,5-10m up to 90 m and length - from 5-15 m to 140 km. The orientation of the bulk of dykes coincides with the direction of the major structural and tectonic lineaments of the region. Dykes are often refer to the fault planes. The composition of dykes may vary along the stretches. The density of hundreds of basaltic dykes and small intrusions in the dyke swarms is not permanent and sometimes essentially uneven. They form a compact dyke swarms of dykes, stocks and sub layering bodies veins. In dyke package on Huor-Uyallah river here are 20 subparallel dykes of different chemical composition at a distance of 2 km Lack of the evidence of the dykes crossing allows to assume their formation during the same magmatic cycle. Dykes cross cut through the entire incision of basaltic plateau. They did not created the flow effusions and refer to the final stage trap magmatism. Ar/Ar age of the youngest dykes in the province Kamenska 238-247 Ma. the age of lamproite dyke in Norilsk province is 235 Ma. Dykes are represented by dolerites trachydolerites, syenites, minettes, lamprophyres (camptonite, spessartite, vosgesite), avgitites, melanephelinite, alnoites, limburgites alkaline picrites, meimechites. Their content vary widely: SiO2 - 35,7-62,6; TiO2- 0,4-7,5; Al2O3- 4,4-17,5; Fe2O3- 4,6-20,6; MnO- 0,08-0,44; MgO- 0,8-31,5; CaO- 0,7-15,4; Na2O- 0,01-6,5; K2O 0,8-5,3 wt.%; P2O5 0,1-1,2 wt.%. The h Bolsheavamskaya volcanic basin in Kamensky province is most abundant in

  2. Seismicity of the Earth 1900‒2013 Mediterranean Sea and vicinity

    USGS Publications Warehouse

    Herman, Matthew W.; Hayes, Gavin P.; Smoczyk, Gregory M.; Turner, Rebecca; Turner, Bethan; Jenkins, Jennifer; Davies, Sian; Parker, Amy; Sinclair, Allison; Benz, Harley M.; Furlong, Kevin P.; Villaseñor, Antonio

    2015-09-08

    The Mediterranean region is seismically active due to the convergence of the Africa Plate with the Eurasia plate. Present day Africa-Eurasia motion ranges from ~4 millimeters per year (mm/yr) in a northwest-southeast direction in the western Mediterranean to ~10 mm/yr (north-south) in the eastern Mediterranean. The Africa-Eurasia plate boundary is complex, and includes extensional and translational zones in addition to the dominant convergent regimes characterized by subduction and continental collision. This convergence began at approximately 50 million years ago and was associated with the closure of the Tethys Sea; the Mediterranean Sea is all that remains of the Tethys. The highest rates of seismicity in the Mediterranean region are found along the Hellenic subduction zone of southern Greece and the North Anatolian Fault Zone of northwestern Turkey, but significant rates of current seismicity and large historical earthquakes have occurred throughout the region spanning the Mediterranean Sea.

  3. Seismicity of the Earth 1900‒2013 Mediterranean Sea and vicinity

    USGS Publications Warehouse

    Herman, Matthew W.; Hayes, Gavin P.; Smoczyk, Gregory M.; Turner, Rebecca; Turner, Bethan; Jenkins, Jennifer; Davies, Sian; Parker, Amy; Sinclair, Allison; Benz, Harley M.; Furlong, Kevin P.; Villaseñor, Antonio

    2015-01-01

    The Mediterranean region is seismically active due to the convergence of the Africa Plate with the Eurasia plate. Present day Africa-Eurasia motion ranges from ~4 millimeters per year (mm/yr) in a northwest-southeast direction in the western Mediterranean to ~10 mm/yr (north-south) in the eastern Mediterranean. The Africa-Eurasia plate boundary is complex, and includes extensional and translational zones in addition to the dominant convergent regimes characterized by subduction and continental collision. This convergence began at approximately 50 million years ago and was associated with the closure of the Tethys Sea; the Mediterranean Sea is all that remains of the Tethys. The highest rates of seismicity in the Mediterranean region are found along the Hellenic subduction zone of southern Greece and the North Anatolian Fault Zone of northwestern Turkey, but significant rates of current seismicity and large historical earthquakes have occurred throughout the region spanning the Mediterranean Sea.

  4. New records of Merriam’s Shrew (Sorex merriami) from western North Dakota

    USGS Publications Warehouse

    M. J.Shaughnessy Jr.,; Woodman, Neal

    2015-01-01

    Despite having a broad geographic distribution, Merriam's Shrew (Sorex merriami Dobson 1890) is known from a relatively few, widely-scattered localities. In North Dakota, the species was known from only a single poorly-preserved specimen collected in 1913 near Medora. We recently collected two new specimens of Merriam's Shrew from Billings and McKenzie counties in the western quarter of the state. These specimens confirm the presence of S. merriami in North Dakota and better define the northeastern edge of the species' distribution.

  5. Investigating the presence of organochlorine pesticides and polychlorinated biphenyls in wild and farmed gilthead sea bream (Sparus aurata) from the Western Mediterranean sea.

    PubMed

    Serrano, Roque; Barreda, Mercedes; Blanes, Miguel A

    2008-05-01

    The presence of organochlorine pesticides and polychlorinated biphenyls in wild and farmed gilthead sea bream (Sparus aurata) from the Western Mediterranean, Spain, is investigated. These pollutants were determined in white and red muscle and liver by gas chromatography coupled to tandem mass spectrometry. Contaminant profiles present in both wild and farmed fish tissues include DDTs, PCBs and HCB. The highest concentrations of contaminants were found in liver, and an increase in pollutant levels was observed in autumn, before spawning. This fact is explained in light of increased food intake when sea water temperatures increase. Gilthead sea bream from Western Mediterranean populations showed significantly higher concentrations of DDTs and PCBs than farmed fish from the same area. This fact is attributed to the low level of organochlorine contaminants present in fish feed supplied to the cultured fish. The diet is highlighted as an important factor in understanding differences observed in organochlorine pollutants levels of fish tissues.

  6. Geographical variation in metazoan parasites of the deep-sea fish Bathypterois mediterraneus Bauchot, 1962 (Osteichthyes: Ipnopidae) from the Western Mediterranean

    NASA Astrophysics Data System (ADS)

    Mateu, Paula; Montero, Francisco E.; Carrassón, Maite

    2014-05-01

    This study examines the parasite fauna of Bathypterois mediterraneus, the most common fish below 1500 m in Western Mediterranean waters. Samples were obtained during July 2010 from the continental slope of two different areas (off Catalonia and Balearic Islands) in three different bathymetric strata at depths between 1000 and 2200 m. The parasite fauna of B. mediterraneus included a narrow range of species: Steringophorus cf. dorsolineatum, Scolex pleuronectis, Hysterothylacium aduncum, Anisakis sp. larva 3 type II and Sarcotretes sp. Steringophorus cf. dorsolineatum and H. aduncum were the most predominant parasites. H. aduncum showed significant differences in abundance between depths of 2000-2200 m with 1000-1400 m and 1400-2000 m, irrespective of locality, whereas S. cf. dorsolineatum showed significant differences between the two localities at all depths except for 2000-2200 m. We suggest the possible usefulness of these two parasites as geographical indicators for discriminating discrete stocks of B. mediterraneus in Western Mediterranean waters.

  7. Rare earth element transport in the western North Atlantic inferred from Nd isotopic observations

    NASA Technical Reports Server (NTRS)

    Piepgras, D. J.; Wasserburg, G. J.

    1987-01-01

    The relationship between the Nd isotopic composition in the Atlantic waters and the origin and circulation of the water masses was investigated. Samples were collected in the western North Atlantic between 7 and 54 deg N. The isotopic composition (Nd-143/Nd-144 ratios) showed extensive vertical structure at all locations. In regions where a thermocline was well-developed, large isotopic shifts were observed across the base of the thermocline, while regions without a thermocline were characterized by much more gradual shifts in isotopic composition with depth. The data reveal an excellent correlation between the Nd isotopic distribution in the western North Atlantic water column and the distribution of water masses identified from temperature and salinity measurements.

  8. Late Ordovician-Early Silurian chitinozoans from north-eastern and western Illinois, USA

    USGS Publications Warehouse

    Butcher, A.; Mikulic, Donald G.; Kluessendorf, Joanne

    2010-01-01

    Samples of uppermost Ordovician and Silurian strata from two cores from north-eastern and western Illinois were processed for chitinozoans. Due to apparent sea-floor oxidation or palaeoenvironmental constraints, very few samples yielded specimens, but those that did allow tentative correlation with established biostratigraphical zonations for the Chitinozoa. Samples from the Wilhelmi Formation of core DH76-21 in north-eastern Illinois yielded Spinachitina fragilis, a typically earliest Silurian taxon. A sample from the Maquoketa Group strata of core Principia #4, western Illinois, yielded a monospecific assemblage of Conochitina elegans, which is suggestive of a late Ordovician age. Higher in this core, a sample from the upper strata of the Bowling Green Dolomite yielded an assemblage indicating a late Rhuddanian to Aeronian age, including Angochitina hansonica, previously only described from strata in Nevada, and one new species, Fungochitina illinoisensis. ?? 2009 Elsevier B.V. All rights reserved.

  9. Assimilation of lidar signals: application to aerosol forecasting in the western Mediterranean basin

    NASA Astrophysics Data System (ADS)

    Wang, Y.; Sartelet, K. N.; Bocquet, M.; Chazette, P.; Sicard, M.; D'Amico, G.; Léon, J. F.; Alados-Arboledas, L.; Amodeo, A.; Augustin, P.; Bach, J.; Belegante, L.; Binietoglou, I.; Bush, X.; Comerón, A.; Delbarre, H.; García-Vízcaino, D.; Guerrero-Rascado, J. L.; Hervo, M.; Iarlori, M.; Kokkalis, P.; Lange, D.; Molero, F.; Montoux, N.; Muñoz, A.; Muñoz, C.; Nicolae, D.; Papayannis, A.; Pappalardo, G.; Preissler, J.; Rocadenbosch, F.; Sellegri, K.; Wagner, F.; Dulac, F.

    2014-11-01

    This paper presents a new application of assimilating lidar signals to aerosol forecasting. It aims at investigating the impact of a ground-based lidar network on the analysis and short-term forecasts of aerosols through a case study in the Mediterranean basin. To do so, we employ a data assimilation (DA) algorithm based on the optimal interpolation method developed in the Polair3D chemistry transport model (CTM) of the Polyphemus air quality modelling platform. We assimilate hourly averaged normalised range-corrected lidar signals (PR2) retrieved from a 72 h period of intensive and continuous measurements performed in July 2012 by ground-based lidar systems of the European Aerosol Research Lidar Network (EARLINET) integrated into the Aerosols, Clouds, and Trace gases Research InfraStructure (ACTRIS) network and an additional system in Corsica deployed in the framework of the pre-ChArMEx (Chemistry-Aerosol Mediterranean Experiment)/TRAQA (TRAnsport à longue distance et Qualité de l'Air) campaign. This lidar campaign was dedicated to demonstrating the potential operationality of a research network like EARLINET and the potential usefulness of assimilation of lidar signals to aerosol forecasts. Particles with an aerodynamic diameter lower than 2.5 μm (PM2.5) and those with an aerodynamic diameter higher than 2.5 μm but lower than 10 μm (PM10-2.5) are analysed separately using the lidar observations at each DA step. First, we study the spatial and temporal influences of the assimilation of lidar signals on aerosol forecasting. We conduct sensitivity studies on algorithmic parameters, e.g. the horizontal correlation length (Lh) used in the background error covariance matrix (50 km, 100 km or 200 km), the altitudes at which DA is performed (0.75-3.5 km, 1.0-3.5 km or 1.5-3.5 km a.g.l.) and the assimilation period length (12 h or 24 h). We find that DA with Lh = 100 km and assimilation from 1.0 to 3.5 km a.g.l. during a 12 h assimilation period length leads to the

  10. Avian mercury exposure and toxicological risk across western North America: A synthesis

    USGS Publications Warehouse

    Ackerman, Josh; Eagles-Smith, Collin A.; Herzog, Mark; Hartman, Christopher; Peterson, Sarah; Evers, David C.; Jackson, Allyson K.; Elliott, John E.; Vander Pol, Stacy S.; Bryan, Colleen E.

    2016-01-01

    Methylmercury contamination of the environment is an important issue globally, and birds are useful bioindicators for mercury monitoring programs. The available data on mercury contamination of birds in western North America were synthesized. Original data from multiple databases were obtained and a literature review was conducted to obtain additional mercury concentrations. In total, 29219 original bird mercury concentrations from 225 species were compiled, and an additional 1712 mean mercury concentrations, representing 19998 individuals and 176 species, from 200 publications were obtained. To make mercury data comparable across bird tissues, published equations of tissue mercury correlations were used to convert all mercury concentrations into blood-equivalent mercury concentrations. Blood-equivalent mercury concentrations differed among species, foraging guilds, habitat types, locations, and ecoregions. Piscivores and carnivores exhibited the greatest mercury concentrations, whereas herbivores and granivores exhibited the lowest mercury concentrations. Bird mercury concentrations were greatest in ocean and salt marsh habitats and lowest in terrestrial habitats. Bird mercury concentrations were above toxicity benchmarks in many areas throughout western North America, and multiple hotspots were identified. Additionally, published toxicity benchmarks established in multiple tissues were summarized and translated into a common blood-equivalent mercury concentration. Overall, 66% of birds sampled in western North American exceeded a blood-equivalent mercury concentration of 0.2 μg/g wet weight (ww; above background levels), which is the lowest-observed effect level, 28% exceeded 1.0 μg/g ww (moderate risk), 8% exceeded 3.0 μg/g ww (high risk), and 4% exceeded 4.0 μg/g ww (severe risk). Mercury monitoring programs should sample bird tissues, such as adult blood and eggs, that are most-easily translated into tissues with well-developed toxicity benchmarks and that

  11. Trans-Pacific transport of Saharan dust to western North America: A case study

    NASA Astrophysics Data System (ADS)

    McKendry, Ian G.; Strawbridge, Kevin B.; O'Neill, Norman T.; MacDonald, Anne Marie; Liu, Peter S. K.; Leaitch, W. Richard; Anlauf, Kurt G.; Jaegle, Lyatt; Fairlie, T. Duncan; Westphal, Douglas L.

    2007-01-01

    The first documented case of long-range transport of Saharan dust over a pathway spanning Asia and the Pacific to western North America is described. Crustal material generated by North African dust storms during the period 28 February to 3 March 2005 reached western Canada on 13-14 March 2005 and was observed by lidar and sunphotometer in the Vancouver region and by high-altitude aerosol instrumentation at Whistler Peak. Global chemical models (GEOS-Chem and NRL NAAPS) confirm the transport pathway and suggest source attribution was simplified in this case by the distinct, and somewhat unusual, lack of dust activity over Eurasia (Gobi and Takla Makan deserts) at this time. Over western North America the dust layer, although subsiding close to the boundary layer, did not appear to contribute to boundary layer particulate matter concentrations. Furthermore, sunphotometer observations (and associated inversion products) suggest that the dust layer had only subtle optical impact (aerosol optical thickness (τa500) and Ångström exponent (α440-870) were 0.1 and 1.2, respectively) and was dominated by fine particulate matter (modes in aerodynamic diameter at 0.3 and 2.5 μm). High-altitude observations at Whistler, British Columbia, confirm the crustal origin of the layer (rich in Ca++ ions) and the bimodal size distribution. Although a weak event compared to the Asian trans-Pacific dust events of 1998 and 2001, this novel case highlights the possibility that Saharan sources may contribute episodically to the aerosol burden in western North America.

  12. Trans-Pacific Transport of Saharan Dust to Western North America: A Case Study

    NASA Technical Reports Server (NTRS)

    Kendry, Ian G. M.; Strawbridge, Kevin B.; O'Neill, Norman; Macdonald, Anne Marie; Liu, Peter S. K.; Leaitch, W. Richard; Anlauf, Kurt G.; Jaegle, Lyatt; Fairlie, T. Duncan; Westphal, Douglas L.

    2007-01-01

    The first documented case of long range transport of Saharan dust over a pathway spanning Asia and the Pacific to Western North America is described. Crustal material generated by North African dust storms during the period 28 February - 3 March 2005 reached western Canada on 13-14 March 2005 and was observed by lidar and sunphotometer in the Vancouver region and by high altitude aerosol instrumentation at Whistler Peak. Global chemical models (GEOS-CHEM and NRL NAAPS) confirm the transport pathway and suggest source attribution was simplified in this case by the distinct, and somewhat unusual, lack of dust activity over Eurasia (Gobi and Takla Makan deserts) at this time. Over western North America, the dust layer, although subsiding close to the boundary layer, did not appear to contribute to boundary layer particulate matter concentrations. Furthermore, sunphotometer observations (and associated inversion products) suggest that the dust layer had only subtle optical impact (Aerosol Optical Thickness (Tau(sub a500)) and Angstrom exponent (Alpha(sub 440-870) were 0.1 and 1.2 respectively) and was dominated by fine particulate matter (modes in aerodynamic diameter at 0.3 and 2.5microns). High Altitude observations at Whistler BC, confirm the crustal origin of the layer (rich in Ca(++) ions) and the bi-modal size distribution. Although a weak event compared to the Asian Trans-Pacific dust events of 1998 and 2001, this novel case highlights the possibility that Saharan sources may contribute episodically to the aerosol burden in western North America.

  13. Organic compounds temporal trends at some invertebrate species from the Balearics, Western Mediterranean.

    PubMed

    Deudero, S; Box, A; March, D; Valencia, J M; Grau, A M; Tintore, J; Calvo, M; Caixach, J

    2007-08-01

    Concentrations of persistent organic pollutants (POPs) such as hexachlorobenzene (HCB), dichlore diphenyl trichloretane (DDT), polychlorinated biphenyls (PCBs), and gamma-hexachlorocyclohexane (gamma-HCH or lindane) were determined in tissue of marine benthic invertebrates such as Mytilus galloprovincialis, Chamelea gallina, Venus verrucosa, Lithophaga lithophaga and Paracentrotus lividus. Species were selected due to their habitat, trophic level, feeding behaviour and their consumption. Invertebrate species were systematically sampled from December 1996 to December 2005 from several sites along the Balearic Islands. The highest concentrations of PCBs (785ng/g lipid) were found in M. galloprovincialis while the lowest concentrations were found in the sea-urchin P. lividus (193ng/g lipid). Among the 7 PCB quantified congeners the higher values are mainly obtained for CB138 and CB153. All bivalves presented higher PCBs contents than the sea-urchin P. lividus are possibly linked with the bioaccumulation process of POPs throughout the food web and to differential detoxifying mechanisms. The concentration of SigmaDDT exceeds that of HCB and gamma-HCH at all species and sampling stations. DDT concentrations ranged from 0.4ng/g ww at the bivalve C. gallina in 2002, to values of 15.8ng/g ww at the bivalve L. lithophaga in 1998. The values obtained for the organic compounds (HCH, HCB, PCBs, DDT) depend upon the place and year of sampling and are compared to values found by other authors for the mussel M. galloprovincialis in other Mediterranean areas. gamma-HCH and HCB were found in lower concentrations than the other POPs. PMID:17524450

  14. Pockets, conduits, channels, and plumes: links to volcanism and orogeny in the rollback dominated western Mediterranean

    NASA Astrophysics Data System (ADS)

    Miller, Meghan S.; Sun, Daoyuan; O'Driscoll, Leland; Becker, Thorsten W.; Holt, Adam; Diaz, Jordi; Thomas, Christine

    2015-04-01

    Detailed mantle and lithospheric structure from the Canary Islands to Iberia have been imaged with data from recent temporary deployments and select permanent stations from over 300 broadband seismometers. The stations extended across Morocco and Spain as part of the PICASSO, IberArray, and Morocco-Münster experiments. We present results from S receiver functions (SRF), shear wave splitting, waveform modeling, and geodynamic models that help constrain the tectonic evolution of the westernmost Mediterranean, including orogenesis of the Atlas Mountains and occurrence of localized alkaline volcanism. Our receiver function images, in agreement with previous geophysical modeling, show that the lithosphere is thin (~65 km) beneath the Atlas, but thickens (~100 km) over a very short length scale at the flanks of the mountains. We find that these dramatic changes in lithospheric thickness also correspond to dramatic decreases in delay times inferred from S and SKS splitting observations of seismic anisotropy. Pockets and conduits of low seismic velocity material below the lithosphere extend along much of the Atlas to Southern Spain and correlate with the locations of Pliocene-Quaternary magmatism. Waveform analysis from the USC linear seismic array across the Atlas Mountains constrains the position, shape, and physical characteristics of one localized, low velocity conduit that extends from the uppermost mantle (~200 km depth) up to the volcanoes in the Middle Atlas. The shape, position and temperature of these seismically imaged low velocity anomalies, topography of the base of the lithosphere, morphology of the subducted slab beneath the Alboran Sea, position of the West African Craton and correlation with mantle flow inferred from shear wave splitting suggest that the unusually high topography of the Atlas Mountains and isolated recent volcanics are due to active mantle support that may be from material channeled from the Canary Island plume.

  15. Magmatic evolution of the Alboran region: The role of subduction in forming the western Mediterranean and causing the Messinian Salinity Crisis

    NASA Astrophysics Data System (ADS)

    Duggen, Svend; Hoernle, Kaj; van den Bogaard, Paul; Harris, Chris

    2004-01-01

    The magmatic evolution of the Alboran region (westernmost Mediterranean) contains important clues for improving our understanding of the origin of Mediterranean-style back-arc basins and the desiccation of the Mediterranean Sea in the Messinian. We use new laser 40Ar/ 39Ar age and geochemical (major and trace element and O-Sr-Nd-Pb isotope) data from igneous rocks from southern Spain, the Alboran Sea and northern Morocco to reconstruct the magmatic evolution of the westernmost Mediterranean since the Eocene. Lower Oligocene dikes near Malaga (33.6±0.6 Ma) and Middle to Upper Miocene volcanic rocks from the Alboran Sea area (6.57±0.04 to 11.8±0.4 Ma) can be subdivided into two groups: (1) LREE-depleted (relative to N-MORB), primarily tholeiitic series, and (2) LREE-enriched, primarily calc-alkaline series volcanic rocks. Both groups are generally enriched in fluid-mobile elements (e.g. Rb, Th, U, K and Pb) relative to fluid-immobile elements (e.g. Nb, Ta, LREE). The LREE-depleted group has 143Nd/ 144Nd (0.5128-0.5130) isotope ratios similar to Atlantic MORB but higher 87Sr/ 86Sr (0.7046-0.7100). In contrast, the LREE-enriched group has less radiogenic Nd (0.5121-0.5126) and tend to more radiogenic Sr (0.7066-0.7205) isotopic composition. Pb isotope ratios are surprisingly uniform and have compositions similar to marine sediments. Analyses of mineral separates show that mafic melts with relatively low δ 18O (5.6-7.2‰) had high 87Sr/ 86Sr (0.7048-0.7088), Δ7/4 (10.6-14.1) and Δ8/4 (40.0-49.3). Modeling of the trace elements and Sr-Nd-Pb-O isotopic compositions provides compelling evidence for the contamination of the mantle source with hydrous fluids/melts, which can be explained through subduction of oceanic lithosphere beneath the Alboran Basin but not through detachment/delamination of lithospheric mantle. We present a geodynamic model that reconstructs the Late Eocene to Quaternary evolution of the western Mediterranean through westward roll-back of

  16. First Detection of Bat White-Nose Syndrome in Western North America

    PubMed Central

    Palmer, Jonathan M.; Lindner, Daniel L.; Ballmann, Anne E.; George, Kyle G.; Griffin, Kathryn; Knowles, Susan; Huckabee, John R.; Haman, Katherine H.; Anderson, Christopher D.; Becker, Penny A.; Buchanan, Joseph B.; Foster, Jeffrey T.; Blehert, David S.

    2016-01-01

    ABSTRACT White-nose syndrome (WNS) is an emerging fungal disease of bats caused by Pseudogymnoascus destructans. Since it was first detected near Albany, NY, in 2006, the fungus has spread across eastern North America, killing unprecedented numbers of hibernating bats. The devastating impacts of WNS on Nearctic bat species are attributed to the likely introduction of P. destructans from Eurasia to naive host populations in eastern North America. Since 2006, the disease has spread in a gradual wavelike pattern consistent with introduction of the pathogen at a single location. Here, we describe the first detection of P. destructans in western North America in a little brown bat (Myotis lucifugus) from near Seattle, WA, far from the previously recognized geographic distribution of the fungus. Whole-genome sequencing and phylogenetic analyses indicated that the isolate of P. destructans from Washington grouped with other isolates of a presumed clonal lineage from the eastern United States. Thus, the occurrence of P. destructans in Washington does not likely represent a novel introduction of the fungus from Eurasia, and the lack of intensive surveillance in the western United States makes it difficult to interpret whether the occurrence of P. destructans in the Pacific Northwest is disjunct from that in eastern North America. Although there is uncertainty surrounding the impacts of WNS in the Pacific Northwest, the presence of the pathogen in western North America could have major consequences for bat conservation. IMPORTANCE White-nose syndrome (WNS) represents one of the most consequential wildlife diseases of modern times. Since it was first documented in New York in 2006, the disease has killed millions of bats and threatens several formerly abundant species with extirpation or extinction. The spread of WNS in eastern North America has been relatively gradual, inducing optimism that disease mitigation strategies could be established in time to conserve bats

  17. First Detection of Bat White-Nose Syndrome in Western North America.

    PubMed

    Lorch, Jeffrey M; Palmer, Jonathan M; Lindner, Daniel L; Ballmann, Anne E; George, Kyle G; Griffin, Kathryn; Knowles, Susan; Huckabee, John R; Haman, Katherine H; Anderson, Christopher D; Becker, Penny A; Buchanan, Joseph B; Foster, Jeffrey T; Blehert, David S

    2016-01-01

    White-nose syndrome (WNS) is an emerging fungal disease of bats caused by Pseudogymnoascus destructans. Since it was first detected near Albany, NY, in 2006, the fungus has spread across eastern North America, killing unprecedented numbers of hibernating bats. The devastating impacts of WNS on Nearctic bat species are attributed to the likely introduction of P. destructans from Eurasia to naive host populations in eastern North America. Since 2006, the disease has spread in a gradual wavelike pattern consistent with introduction of the pathogen at a single location. Here, we describe the first detection of P. destructans in western North America in a little brown bat (Myotis lucifugus) from near Seattle, WA, far from the previously recognized geographic distribution of the fungus. Whole-genome sequencing and phylogenetic analyses indicated that the isolate of P. destructans from Washington grouped with other isolates of a presumed clonal lineage from the eastern United States. Thus, the occurrence of P. destructans in Washington does not likely represent a novel introduction of the fungus from Eurasia, and the lack of intensive surveillance in the western United States makes it difficult to interpret whether the occurrence of P. destructans in the Pacific Northwest is disjunct from that in eastern North America. Although there is uncertainty surrounding the impacts of WNS in the Pacific Northwest, the presence of the pathogen in western North America could have major consequences for bat conservation. IMPORTANCE White-nose syndrome (WNS) represents one of the most consequential wildlife diseases of modern times. Since it was first documented in New York in 2006, the disease has killed millions of bats and threatens several formerly abundant species with extirpation or extinction. The spread of WNS in eastern North America has been relatively gradual, inducing optimism that disease mitigation strategies could be established in time to conserve bats susceptible

  18. Designing conservation strategies to preserve the genetic diversity of Astragalus edulis Bunge, an endangered species from western Mediterranean region.

    PubMed

    Peñas, Julio; Barrios, Sara; Bobo-Pinilla, Javier; Lorite, Juan; Martínez-Ortega, M Montserrat

    2016-01-01

    Astragalus edulis (Fabaceae) is an endangered annual species from the western Mediterranean region that colonized the SE Iberian Peninsula, NE and SW Morocco, and the easternmost Macaronesian islands (Lanzarote and Fuerteventura). Although in Spain some conservation measures have been adopted, it is still necessary to develop an appropriate management plan to preserve genetic diversity across the entire distribution area of the species. Our main objective was to use population genetics as well as ecological and phylogeographic data to select Relevant Genetic Units for Conservation (RGUCs) as the first step in designing conservation plans for A. edulis. We identified six RGUCs for in situ conservation, based on estimations of population genetic structure and probabilities of loss of rare alleles. Additionally, further population parameters, i.e. occupation area, population size, vulnerability, legal status of the population areas, and the historical haplotype distribution, were considered in order to establish which populations deserve conservation priority. Three populations from the Iberian Peninsula, two from Morocco, and one from the Canary Islands represent the total genetic diversity of the species and the rarest allelic variation. Ex situ conservation is recommended to complement the preservation of A. edulis, given that effective in situ population protection is not feasible in all cases. The consideration of complementary phylogeographic and ecological data is useful for management efforts to preserve the evolutionary potential of the species. PMID:26844014

  19. Designing conservation strategies to preserve the genetic diversity of Astragalus edulis Bunge, an endangered species from western Mediterranean region

    PubMed Central

    Barrios, Sara; Bobo-Pinilla, Javier; Lorite, Juan; Martínez-Ortega, M. Montserrat

    2016-01-01

    Astragalus edulis (Fabaceae) is an endangered annual species from the western Mediterranean region that colonized the SE Iberian Peninsula, NE and SW Morocco, and the easternmost Macaronesian islands (Lanzarote and Fuerteventura). Although in Spain some conservation measures have been adopted, it is still necessary to develop an appropriate management plan to preserve genetic diversity across the entire distribution area of the species. Our main objective was to use population genetics as well as ecological and phylogeographic data to select Relevant Genetic Units for Conservation (RGUCs) as the first step in designing conservation plans for A. edulis. We identified six RGUCs for in situ conservation, based on estimations of population genetic structure and probabilities of loss of rare alleles. Additionally, further population parameters, i.e. occupation area, population size, vulnerability, legal status of the population areas, and the historical haplotype distribution, were considered in order to establish which populations deserve conservation priority. Three populations from the Iberian Peninsula, two from Morocco, and one from the Canary Islands represent the total genetic diversity of the species and the rarest allelic variation. Ex situ conservation is recommended to complement the preservation of A. edulis, given that effective in situ population protection is not feasible in all cases. The consideration of complementary phylogeographic and ecological data is useful for management efforts to preserve the evolutionary potential of the species. PMID:26844014

  20. Spatial and temporal variation of seasonal synchrony in the deep-sea shrimp Aristeus antennatus in the Western Mediterranean

    NASA Astrophysics Data System (ADS)

    Hidalgo, Manuel; Rueda, Lucía; Molinero, Juan Carlos; Guijarro, Beatriz; Massutí, Enric

    2015-08-01

    Resolving drivers of spatial synchrony in marine species is fundamental for the management and conservation of deep-sea ecosystems. Here we examine an 11-year data set of monthly catches per unit of effort (CPUE) of the red-shrimp Aristeus antennatus. These data comprise 16 locations of two population subunits in the Western Mediterranean, the Catalan coast and the Balearic archipelago. The analysis of their seasonal covariation and its space-time structure showed small-scale geographical segregation of locations linked with the seasonal fluctuations of CPUE. Results further revealed that seasonal synchrony dominates at short spatial scales (ca. 50 km), while asynchrony prevails are broader spatial scales (ca. 200-300 km). This spatial pattern, however, varied over the period examined, although it was specific for each population subunit suggesting contrasting drivers of seasonal synchrony. The Balearic Islands, a patchier population subunit, displayed a seasonal synchrony pattern mainly dependent on biological and oceanographic processes at local scales. By contrast, in the Catalan coast, the pattern appeared related with regional-scale climate, which triggers spatial differences in the phenology of primary producers and the timing of food advection to the seabed. These cascading processes depicted by our investigation shed light on underlying mechanisms shaping the temporal synchrony of broadly distributed deep-sea populations.

  1. Designing conservation strategies to preserve the genetic diversity of Astragalus edulis Bunge, an endangered species from western Mediterranean region.

    PubMed

    Peñas, Julio; Barrios, Sara; Bobo-Pinilla, Javier; Lorite, Juan; Martínez-Ortega, M Montserrat

    2016-01-01

    Astragalus edulis (Fabaceae) is an endangered annual species from the western Mediterranean region that colonized the SE Iberian Peninsula, NE and SW Morocco, and the easternmost Macaronesian islands (Lanzarote and Fuerteventura). Although in Spain some conservation measures have been adopted, it is still necessary to develop an appropriate management plan to preserve genetic diversity across the entire distribution area of the species. Our main objective was to use population genetics as well as ecological and phylogeographic data to select Relevant Genetic Units for Conservation (RGUCs) as the first step in designing conservation plans for A. edulis. We identified six RGUCs for in situ conservation, based on estimations of population genetic structure and probabilities of loss of rare alleles. Additionally, further population parameters, i.e. occupation area, population size, vulnerability, legal status of the population areas, and the historical haplotype distribution, were considered in order to establish which populations deserve conservation priority. Three populations from the Iberian Peninsula, two from Morocco, and one from the Canary Islands represent the total genetic diversity of the species and the rarest allelic variation. Ex situ conservation is recommended to complement the preservation of A. edulis, given that effective in situ population protection is not feasible in all cases. The consideration of complementary phylogeographic and ecological data is useful for management efforts to preserve the evolutionary potential of the species.

  2. Tree species diversity of natural mixed stands in eastern Black Sea and western Mediterranean region of Turkey.

    PubMed

    Ozcelik, Ramazan

    2009-09-01

    Differences in free species diversity of natural mixed stands were compared between the eastern Black sea region (EBSR) and western Mediterranean region (WMR) of Turkey, to clarify the effects of differences in forest structure, focusing on the tree species occurring in each. Species diversity with special reference to stand structure, of natural mixed stands was quantified by Shannon-Wiener index (H'), equitability index (J'), and species richness index (R). All species diversity indices were significantly higher in EBSR than in WMR. According to the coefficients of homogeneity (CH), stands in EBSR are generally have uneven-aged stand structure, but in WMR even-aged stand structure is more common. Uneven-aged stands have more tree species diversity than even-aged forests due to complex vertical forest structure and species composition. According to Pearson's coefficients, species diversity indices and richness are closely related the average stand diameter (Ds) in uneven-aged stands of EBSR, but average stand diameter (Ds), age (A), and stand density (SDI) are the most important stand parameters in even-aged stands of WMR in Turkey.

  3. Dichelyne (Cucullanellus) romani n. sp. (Nematoda: Cucullanidae) in notacanthid fishes from the Northeast Atlantic and Western Mediterranean.

    PubMed

    Isbert, Wolf; Montero, Francisco Esteban; Carrassón, Maite; González-Solís, David

    2015-05-01

    A new cucullanid, Dichelyne (Cucullanellus) romani n. sp. (Nematoda: Cucullanidae), is described from the digestive tract of two notacanthid fishes, Notacanthus chemnitzii Bloch and N. bonaparte Risso (Notacanthiformes: Notacanthidae), from the Northeast Atlantic and Western Mediterranean. The presence of a precloacal sucker and ten pairs of caudal papillae in males allocates it to the subgenus Cucullanellus Törnquist, 1931. The new species differs from other members of this subgenus in its larger body size, smaller spicule/body length ratio, the distribution of caudal papillae, and the position of deirids and excretory pore. Both notacanthid fishes act as definitive hosts with slightly larger nematode specimens detected in N. chemnitzii. A wide intraspecific variability was found in the distribution of caudal papillae, and in some specimens the position of deirids, excretory pore and length of intestinal caecum also varied. A complete list of all assigned species of the subgenus Cucullanellus is presented and discussed as there are several uncertainties regarding the validity and synonymy of some species. This is the first species of Dichelyne Jägerskiöld, 1902 in a notacanthid fish and one of the only two records in deep-sea fish species.

  4. Bat reproduction declines when conditions mimic climate change projections for western North America.

    PubMed

    Adams, Rick A

    2010-08-01

    Climate change models predict that much of western North America is becoming significantly warmer and drier, resulting in overall reductions in availability of water for ecosystems. Herein, I demonstrate that significant declines in the reproductive success of female insectivorous bats occur in years when annual environmental conditions mimic the long-term predictions of regional climate change models. Using a data set gathered on bat populations from 1996 through 2008 along the Front Range of Colorado, I compare trends in population numbers and reproductive outcomes of six species of vespertilionid bats with data on mean annual high temperature, precipitation, snow pack, and stream discharge rates. I show that levels of precipitation and flow rates of small streams near maternity colonies is fundamentally tied to successful reproduction in female bats, particularly during the lactation phase. Across years that experienced greater than average mean temperatures with less than average precipitation and stream flow, bat populations responded by slight to profound reductions in reproductive output depending on the severity of drought conditions. In particular, reproductive outputs showed profound declines (32-51%) when discharge rates of the largest stream in the field area dropped below 7 m3/s, indicating a threshold response. Such sensitivity to environmental change portends severe impacts to regional bat populations if current scenarios for climate change in western North America are accurate. In addition, bats act as early-warning indicators of large-scale ecological effects resulting from further regional warming and drying trends currently at play in western North America.

  5. Covariability of western tropical Pacific-North Pacific atmospheric circulation during summer

    PubMed Central

    Yun, Kyung-Sook; Yeh, Sang-Wook; Ha, Kyung-Ja

    2015-01-01

    North Pacific subtropical high (NPSH) is permanent high-pressure system over the Northern Pacific Ocean and it extends to the western North Pacific during the boreal summer (June-July-August), which is so called the western North Pacific subtropical high (WNPSH). Here, we examine the covariability of the NPSH-WNPSH during summer using both observation and Coupled Model Intercomparison Project phase 5 (CMIP5) model data. The statistical analyses indicate that the NPSH-WNPSH covariability shows significant decadal variability in the observations, in addition, the in-phase relationship of NPSH-WNPSH is enhanced after the mid-to-late 1990s. A dipole-like sea surface temperature (SST) pattern, i.e., a warming in the western Pacific and a cooling in the eastern Pacific, is dominant after the mid-to-late 1990s, which acts to enhance the covariability of NPSH-WNPSH by modulating the atmospheric teleconnections. However, the covariability of NPSH-WNPSH in the future climate is not much influenced by the anthropogenic forcing but it is largely characterized by the natural decadal-to-interdecadal variability, implying that the enhancement of NPSH-WNPSH covariability after the mid-to-late 1990s could be considered as part of decadal-to-interdecadal variability. PMID:26594044

  6. The intertropical convergence zone modulates intense hurricane strikes on the western North Atlantic margin

    PubMed Central

    van Hengstum, Peter J.; Donnelly, Jeffrey P.; Fall, Patricia L.; Toomey, Michael R.; Albury, Nancy A.; Kakuk, Brian

    2016-01-01

    Most Atlantic hurricanes form in the Main Development Region between 9°N to 20°N along the northern edge of the Intertropical Convergence Zone (ITCZ). Previous research has suggested that meridional shifts in the ITCZ position on geologic timescales can modulate hurricane activity, but continuous and long-term storm records are needed from multiple sites to assess this hypothesis. Here we present a 3000 year record of intense hurricane strikes in the northern Bahamas (Abaco Island) based on overwash deposits in a coastal sinkhole, which indicates that the ITCZ has likely helped modulate intense hurricane strikes on the western North Atlantic margin on millennial to centennial-scales. The new reconstruction closely matches a previous reconstruction from Puerto Rico, and documents a period of elevated intense hurricane activity on the western North Atlantic margin from 2500 to 1000 years ago when paleo precipitation proxies suggest that the ITCZ occupied a more northern position. Considering that anthropogenic warming is predicted to be focused in the northern hemisphere in the coming century, these results provide a prehistoric analog that an attendant northern ITCZ shift in the future may again return the western North Atlantic margin to an active hurricane interval. PMID:26906670

  7. The intertropical convergence zone modulates intense hurricane strikes on the western North Atlantic margin.

    PubMed

    van Hengstum, Peter J; Donnelly, Jeffrey P; Fall, Patricia L; Toomey, Michael R; Albury, Nancy A; Kakuk, Brian

    2016-01-01

    Most Atlantic hurricanes form in the Main Development Region between 9°N to 20°N along the northern edge of the Intertropical Convergence Zone (ITCZ). Previous research has suggested that meridional shifts in the ITCZ position on geologic timescales can modulate hurricane activity, but continuous and long-term storm records are needed from multiple sites to assess this hypothesis. Here we present a 3000 year record of intense hurricane strikes in the northern Bahamas (Abaco Island) based on overwash deposits in a coastal sinkhole, which indicates that the ITCZ has likely helped modulate intense hurricane strikes on the western North Atlantic margin on millennial to centennial-scales. The new reconstruction closely matches a previous reconstruction from Puerto Rico, and documents a period of elevated intense hurricane activity on the western North Atlantic margin from 2500 to 1000 years ago when paleo precipitation proxies suggest that the ITCZ occupied a more northern position. Considering that anthropogenic warming is predicted to be focused in the northern hemisphere in the coming century, these results provide a prehistoric analog that an attendant northern ITCZ shift in the future may again return the western North Atlantic margin to an active hurricane interval. PMID:26906670

  8. The intertropical convergence zone modulates intense hurricane strikes on the western North Atlantic margin

    NASA Astrophysics Data System (ADS)

    van Hengstum, Peter J.; Donnelly, Jeffrey P.; Fall, Patricia L.; Toomey, Michael R.; Albury, Nancy A.; Kakuk, Brian

    2016-02-01

    Most Atlantic hurricanes form in the Main Development Region between 9°N to 20°N along the northern edge of the Intertropical Convergence Zone (ITCZ). Previous research has suggested that meridional shifts in the ITCZ position on geologic timescales can modulate hurricane activity, but continuous and long-term storm records are needed from multiple sites to assess this hypothesis. Here we present a 3000 year record of intense hurricane strikes in the northern Bahamas (Abaco Island) based on overwash deposits in a coastal sinkhole, which indicates that the ITCZ has likely helped modulate intense hurricane strikes on the western North Atlantic margin on millennial to centennial-scales. The new reconstruction closely matches a previous reconstruction from Puerto Rico, and documents a period of elevated intense hurricane activity on the western North Atlantic margin from 2500 to 1000 years ago when paleo precipitation proxies suggest that the ITCZ occupied a more northern position. Considering that anthropogenic warming is predicted to be focused in the northern hemisphere in the coming century, these results provide a prehistoric analog that an attendant northern ITCZ shift in the future may again return the western North Atlantic margin to an active hurricane interval.

  9. Radiostrontium in the western North Pacific: characteristics, behavior, and the Fukushima impact.

    PubMed

    Povinec, Pavel P; Hirose, Katsumi; Aoyama, Michio

    2012-09-18

    The impact of the Fukushima-derived radiostrontium ((90)Sr and (89)Sr) on the western North Pacific Ocean has not been well established, although (90)Sr concentrations recorded in surface seawater offshore of the damaged Fukushima Dai-ichi nuclear power plant were in some areas comparable to or even higher than (as those in December 2011 with 400 kBq m(-3)(90)Sr) the (137)Cs levels. The total amount of (90)Sr released to the marine environment in the form of highly radioactive wastewater could reach about 1 PBq. Long-term series (1960-2010) of (90)Sr concentration measurements in subtropical surface waters of the western North Pacific indicated that its concentration has been decreasing gradually with a half-life of 14 y. The pre-Fukushima (90)Sr levels in surface waters, including coastal waters near Fukushima, were estimated to be 1 Bq m(-3). To better assess the impact of about 4-5 orders of magnitude increased radiostrontium levels on the marine environment, more detail measurements in seawater and biota of the western North Pacific are required.

  10. The intertropical convergence zone modulates intense hurricane strikes on the western North Atlantic margin.

    PubMed

    van Hengstum, Peter J; Donnelly, Jeffrey P; Fall, Patricia L; Toomey, Michael R; Albury, Nancy A; Kakuk, Brian

    2016-01-01

    Most Atlantic hurricanes form in the Main Development Region between 9°N to 20°N along the northern edge of the Intertropical Convergence Zone (ITCZ). Previous research has suggested that meridional shifts in the ITCZ position on geologic timescales can modulate hurricane activity, but continuous and long-term storm records are needed from multiple sites to assess this hypothesis. Here we present a 3000 year record of intense hurricane strikes in the northern Bahamas (Abaco Island) based on overwash deposits in a coastal sinkhole, which indicates that the ITCZ has likely helped modulate intense hurricane strikes on the western North Atlantic margin on millennial to centennial-scales. The new reconstruction closely matches a previous reconstruction from Puerto Rico, and documents a period of elevated intense hurricane activity on the western North Atlantic margin from 2500 to 1000 years ago when paleo precipitation proxies suggest that the ITCZ occupied a more northern position. Considering that anthropogenic warming is predicted to be focused in the northern hemisphere in the coming century, these results provide a prehistoric analog that an attendant northern ITCZ shift in the future may again return the western North Atlantic margin to an active hurricane interval.

  11. Ebro margins sedimentary system in the western Mediterranean Sea, from delta to deep sea

    SciTech Connect

    Nelson, C.H.; Maldonado, A. )

    1988-08-01

    During Holocene high sea level, delta-front lobes of silty mud have deposited beside a lobate Ebro delta. Topset and foreset beds of these lobes extend up to 20 km offshore in up to 30 m of water. Geostrophic currents advect fine silt and clay from river discharge and storm wave resuspension in the delta front and deposit up to 20 m of bottomset beds in a distal prodelta clay belt formed on the inner to middle shelf for 70 km south from the delta. Intensified water circulation and increased bottom-current speeds inhibit prodelta progradation over the outer shelf and north of the delta and south of the clay belt, where the shelf narrows. Deposition of Holocene hemipelagic mud on the upper slope is restricted, but some modern Ebro sediment apparently bypasses to the deep margin. During Pleistocene low sea level, a series of shelf-edge deltas resulted in extensive progradation of foreset mud beds over the continental slope east of the modern delta and south to the Columbretes Islands. In the north, rapid sediment progradation has resulted in large canyons ({plus minus}5 km wide), unconfined sediment gravity flows, and deposition of large sediment aprons (50 km diameter) downslope from canyon mouths. In the south, narrow canyons ({plus minus}2 km wide) have funneled turbidity currents to side-by-side channel-levee complexes younger and smaller to the southwest. Subsidence of the Valencia trough has facilitated sediment transport from these channel-levee complexes into Valencia Valley and thence to the Valencia fan, 200 km to the northeast. Consequently, during low sea level stands a major portion of Ebro sediment is transported north to the Valencia fan, whereas the main progradational history of the Ebro margin has been offshore and to the south of the present delta.

  12. Differing Eocene floral histories in southeastern North America and Western Europe: influence of paleogeography

    USGS Publications Warehouse

    Frederiksen, N.O.

    1995-01-01

    Pollen data show that in southeastern North America, the Eocene angiosperm flora attained its maximum relative diversity some 8 m.y. after the late early Eocene to earliest middle Eocene to earliest middle Eocene climatic maximum. Increasing diversity resulted in part from the flora's position on a large continent which allowed easy migration. In western Europe, the floral diversity began decreasing even before the climatic maximum. Paleogeography played large roles in this diversity decrease. In western Europe, terrestrial floras were on islands and peninsulas in the sea, so that the floras underwent increasing isolation and partial local extermination. Temperate plants generally did not migrate to western Europe, because of a lack of nearby uplands, lack of northern terrestrial source areas for these plants, and presence of the Turgai Straights barrier. -from Authors

  13. Selected plant microfossil records of the terminal Cretaceous event in terrestrial rocks, western North America

    USGS Publications Warehouse

    Nichols, D.J.

    2007-01-01

    Terrestrial or nonmarine rocks of western North America preserve a record of major disruption and permanent alteration of plant communities precisely at the K-T boundary - in the same rocks that preserve geochemical and mineralogical evidence of the terminal Cretaceous impact event. Plant microfossil records from many localities show abrupt disappearance of pollen species (= plant extinctions) closely associated with impact ejecta deposits containing iridium and shocked quartz. Localities discussed in detail in this review are Starkville South, Clear Creek North, Old Raton Pass, and Sugarite in the Raton Basin of Colorado and New Mexico; West Bijou in the Denver Basin, Colorado; Sussex in the Powder River Basin, Wyoming; and Pyramid Butte and Mud Buttes in the Williston Basin, North Dakota. ?? 2007 Elsevier B.V. All rights reserved.

  14. Trends of air pollution in the Western Mediterranean Basin from a 13-year database: A research considering regional, suburban and urban environments in Mallorca (Balearic Islands)

    NASA Astrophysics Data System (ADS)

    Cerro, J. C.; Cerdà, V.; Pey, J.

    2015-02-01

    This study is focused in the evolution of NO, NO2, SO2, O3 and PM10 concentrations, from 2000 to 2012, at urban, suburban and regional observatories in the Balearic Islands (Spain), an insular region in the Western Mediterranean. At urban and suburban areas, daily patterns of most pollutants are strongly linked to land-traffic emissions, being the regional background less influenced. SO2 variations, however, are mostly driven by the impact of other sources different from road traffic, including shipping emissions and power generation. Urban NOx, SO2 and PM10 concentrations exhibit a common weekly pattern, with a very slight accumulation during the weekdays and sharp decreases (15-39%) on weekends. Our long-term database displays clear decreasing NO and NO2 concentrations from 2000 onwards, prominent in the urban environment (-1.1 μg/m3 year), and moderate in suburban and regional areas (up to -0.3 μg/m3 year). At urban sites, O3 behaviour (+1.0 μg/m3 year) is opposite to that of NO, one of its main depletion agents. A moderate O3 increasing trend (+0.5 μg/m3 year) is detected at regional background areas, whereas a modest decreasing trend occurred at the suburban background (-0.4 μg/m3 year), probably caused by enhanced vehicular emissions over these areas induced by urban planning and mobility policies. Finally, substantial PM10 drops are obvious, -0.7 μg/m3 year at urban and suburban areas, and -0.5 μg/m3 year in the regional background. Our results link the sharpest declines to air masses from western to northern sectors, pointing to effective pollution abatement strategies at a European scale. Some additional benefits are connected to the implementation of diverse local policies. The effect of the North Atlantic Oscillation (NAO) was investigated. Negative NAO phases were related to additional air quality benefits, while positive phases mostly contributed to air degradation.

  15. Detection of Anthropogenic pressures on western Mediterranean irrigation systems (La Albufera de Valencia agriculture system, eastern Spain)

    NASA Astrophysics Data System (ADS)

    Pascual-Aguilar, J. A.; Andreu, V.; Picó, Y.

    2012-04-01

    Irrigation systems are considered as one of the major landscapes features in western Mediterranean environments. Both socio-economic and cultural elements are interrelated in their development and preservation. Generally, due to their location in flat lands and close to major urban-industrial zones, irrigation lands are suffering of intense pressures that can alter their agricultural values, environmental quality and, consequently, the sustainability of the systems. To understand the nature of anthropogenic pressures on large Mediterranean water agricultural systems a methodology based on environmental forensics criteria has been developed and applied to La Albufera Natural Park in Valencia (Eastern Spain), a protected area where traditional irrigation systems exists since Muslim times (from 8th to 15th centuries). The study analysed impacts on water and soils, for the first case the fate of emerging contaminants of urban origin (pharmaceuticals and illegal drugs) are analysed. Impact on soils is analysed using the dynamics urban expansion and the loss and fragmentation of soils. The study focused is organised around two major procedures: (1) analysis of 16 water samples to identify the presence of 14 illicit drugs and 17 pharmaceutical compounds by Liquid Chromatography-Mass Spectrometry techniques; (2) spatial analysis with Geographical Information Systems (GIS) integrating different sources and data formats such as water analysis, social, location of sewage water treatment plan and the synchronic comparison of two soil sealing layers -for the years 1991 and 2010. Results show that there is a clear trend in the introduction of pharmaceutical in the irrigation water through previous use of urban consumption and, in many cases, for receiving the effluents of wastewaters treatment plants. Impacts on soils are also important incidence in the fragmentation and disappearance of agricultural land due to soil sealing, even within the protected area of the Natural Park

  16. Late Quaternary Biogeographic and Climatic Changes in Western North America: Evidence From Mapped Arrays of Packrat Midden Data.

    NASA Astrophysics Data System (ADS)

    Strickland, L. E.; Thompson, R. S.; Anderson, K. H.; Pelltier, R. T.

    2005-12-01

    The USGS/NOAA North American Packrat Midden Database is a standardized archive of published paleobotanical data derived from packrat middens in western North America. We use midden age, location, and species presence-absence data from this dataset to generate maps illustrating the past occurrence of important woody plant taxa in western North America during the late Quaternary. We explore late Quaternary changes in the distributions of selected plant taxa commonly found in packrat middens and presently associated with western desert ( Carnegiea gigantea), steppe ( Artemisia tridentata-type), woodland (pinyon pines), montane ( Pinus ponderosa), and subalpine ( Pinus flexilis) plant communities. We compare the current geographic and climatic distributions of these taxa with the present-day climates at sites where these taxa have been found in packrat midden macrofossil assemblages. These comparisons suggest that late Pleistocene climates in western North America were generally characterized by cooler-than-present summers and by much greater-than-present mean annual precipitation.

  17. Causes of daily cycle variability of atmospheric pollutants in a western Mediterranean urban site (DAURE campaign)

    NASA Astrophysics Data System (ADS)

    Reche, Cristina; Moreno, Teresa; Viana, Mar; Querol, Xavier; Alastuey, Andrés.; Jimenez, Jose L.; Pandolfi, Marco; Amato, Fulvio; Pérez, Noemí; Moreno, Natalia

    2010-05-01

    The 2009 DAURE Aerosol Campaign (23-February-2009 to 27-March-2009 and 1-July to 31-July) (see Presentation: Pandolfi et al., section AS3.2) had the objective of characterising the main sources and chemical processes controlling atmospheric pollution due to particulate matter in the Mediterranean site of Barcelona (Spain). An urban and a rural background site were selected in order to describe both kinds of pollution setting. Several parameters were taken into consideration, including the variability of mass concentration in the coarse and fine fractions, particle number, amount of black carbon and the concentration of gaseous pollutants (SO2, H2S, NO, NO2, CO, O3) present. Comparisons between the chemical composition of ambient atmospheric particles during day versus night were made using twelve-hour PM samples. The data shown here are focused on results obtained for the urban site where two main atmospheric settings were distinguishable in winter, namely Atlantic advection versus local air mass recirculation. During the warmer months Saharan dust intrusions added a third important influence on PM background. The data demonstrate that superimposed upon these background influences on city air quality are important local contributions from road traffic, construction-demolition works and shipping. There is also a major local contribution of secondary aerosols, with elevated number of particles occurring at midday (and especially in summer) when nucleation processes are favoured by photochemistry. Concentrations of SO2 peak at different times to the other gaseous pollutants due to regular daytime onshore south-easterly breezes bringing harbour emissions into the city. Road traffic in Barcelona also has a great impact on air quality, as demonstrated by daily and weekly cycles of gaseous pollutants, black carbon and the finer fraction of PM, with peaks being coincident with traffic rush-hours (8-10h and 20-22h), levels of pollution increasing from Monday to Friday, and

  18. Increasing Springtime Ozone Mixing Ratios in the Free Troposphere Over Western North America

    NASA Technical Reports Server (NTRS)

    Cooper, O. R.; Parrish, D. D.; Stohl, A.; Trainer, M.; Nedelec, P.; Thouret, V.; Cammas, J. P.; Oltmans, S. J.; Johnson, B. J.; Tarasick, D.; Leblanc, T.; McDermid, I. S.; Jaffe, D.; Gao, R.; Stith, J.; Ryerson, T.; Aikin, K.; Campos, T.; Weinheimer, A.; Avery, M. A.

    2010-01-01

    In the lowermost layer of the atmosphere - the troposphere - ozone is an important source of the hydroxyl radical, an oxidant that breaks down most pollutants and some greenhouse gases. High concentrations of tropospheric ozone are toxic, however, and have a detrimental effect on human health and ecosystem productivity1. Moreover, tropospheric ozone itself acts as an effective greenhouse gas. Much of the present tropospheric ozone burden is a consequence of anthropogenic emissions of ozone precursors resulting in widespread increases in ozone concentrations since the late 1800s. At present, east Asia has the fastest-growing ozone precursor emissions. Much of the springtime east Asian pollution is exported eastwards towards western North America. Despite evidence that the exported Asian pollution produces ozone, no previous study has found a significant increase in free tropospheric ozone concentrations above the western USA since measurements began in the late 1970s. Here we compile springtime ozone measurements from many different platforms across western North America. We show a strong increase in springtime ozone mixing ratios during 1995-2008 and we have some additional evidence that a similar rate of increase in ozone mixing ratio has occurred since 1984. We find that the rate of increase in ozone mixing ratio is greatest when measurements are more heavily influenced by direct transport from Asia. Our result agrees with previous modelling studies, which indicate that global ozone concentrations should be increasing during the early part of the twenty-first century as a result of increasing precursor emissions, especially at northern mid-latitudes, with western North America being particularly sensitive to rising Asian emissions. We suggest that the observed increase in springtime background ozone mixing ratio may hinder the USA s compliance with its ozone air quality standard.

  19. Increasing springtime ozone mixing ratios in the free troposphere over western North America.

    PubMed

    Cooper, O R; Parrish, D D; Stohl, A; Trainer, M; Nédélec, P; Thouret, V; Cammas, J P; Oltmans, S J; Johnson, B J; Tarasick, D; Leblanc, T; McDermid, I S; Jaffe, D; Gao, R; Stith, J; Ryerson, T; Aikin, K; Campos, T; Weinheimer, A; Avery, M A

    2010-01-21

    In the lowermost layer of the atmosphere-the troposphere-ozone is an important source of the hydroxyl radical, an oxidant that breaks down most pollutants and some greenhouse gases. High concentrations of tropospheric ozone are toxic, however, and have a detrimental effect on human health and ecosystem productivity. Moreover, tropospheric ozone itself acts as an effective greenhouse gas. Much of the present tropospheric ozone burden is a consequence of anthropogenic emissions of ozone precursors resulting in widespread increases in ozone concentrations since the late 1800s. At present, east Asia has the fastest-growing ozone precursor emissions. Much of the springtime east Asian pollution is exported eastwards towards western North America. Despite evidence that the exported Asian pollution produces ozone, no previous study has found a significant increase in free tropospheric ozone concentrations above the western USA since measurements began in the late 1970s. Here we compile springtime ozone measurements from many different platforms across western North America. We show a strong increase in springtime ozone mixing ratios during 1995-2008 and we have some additional evidence that a similar rate of increase in ozone mixing ratio has occurred since 1984. We find that the rate of increase in ozone mixing ratio is greatest when measurements are more heavily influenced by direct transport from Asia. Our result agrees with previous modelling studies, which indicate that global ozone concentrations should be increasing during the early part of the twenty-first century as a result of increasing precursor emissions, especially at northern mid-latitudes, with western North America being particularly sensitive to rising Asian emissions. We suggest that the observed increase in springtime background ozone mixing ratio may hinder the USA's compliance with its ozone air quality standard.

  20. Why were Past North Atlantic Warming Conditions Associated with Drier Climate in the Western United States?

    NASA Astrophysics Data System (ADS)

    Wong, C. I.; Potter, G. L.; Montanez, I. P.; Otto-Bliesner, B. L.; Behling, P.; Oster, J. L.

    2014-12-01

    Investigating climate dynamics governing rainfall over the western US during past warmings and coolings of the last glacial and deglaciation is pertinent to understanding how precipitation patterns might change with future global warming, especially as the processes driving the global hydrological reorganization affecting this drought-prone region during these rapid temperature changes remain unresolved. We present model climates of the Bølling warm event (14,500 years ago) and Younger Dryas cool event (12,200 years ago) that i) uniquely enable the assessment of dueling hypothesis about the atmospheric teleconnections responsible for abrupt temperature shifts in the North Atlantic region to variations in moisture conditions across the western US, and ii) show that existing hypotheses about these teleconnections are unsupported. Modeling results show no evidence for a north-south shift of the Pacific winter storm track, and we argue that a tropical moisture source with evolving trajectory cannot explain alternation between wet/dry conditions, which have been reconstructed from the proxy record. Alternatively, model results support a new hypothesis that variations in the intensity of the winter storm track, corresponding to its expansion/contraction, can account for regional moisture differences between warm and cool intervals of the last deglaciation. Furthermore, we demonstrate that the mechanism forcing the teleconnection between the North Atlantic and western US is the same across different boundary conditions. In our simulation, during the last deglaciation, and in simulations of future warming, perturbation of the Rossby wave structure reconfigures the atmospheric state. This reconfiguration affects the Aleutian Low and high-pressure ridge over and off of the northern North American coastline driving variability in the storm track. Similarity between the processes governing the climate response during these distinct time intervals illustrates the robust nature

  1. Detection of North American eastern and western equine encephalitis viruses by nucleic acid amplification assays.

    PubMed

    Lambert, Amy J; Martin, Denise A; Lanciotti, Robert S

    2003-01-01

    We have developed nucleic acid sequence-based amplification (NASBA), standard reverse transcription PCR (RT-PCR), and TaqMan nucleic acid amplification assays for the rapid detection of North American eastern equine encephalitis (EEE) and western equine encephalitis (WEE) viral RNAs from samples collected in the field and clinical samples. The sensitivities of these assays have been compared to that of virus isolation. While all three types of nucleic acid amplification assays provide rapid detection of viral RNAs comparable to the isolation of viruses in Vero cells, the TaqMan assays for North American EEE and WEE viral RNAs are the most sensitive. We have shown these assays to be specific for North American EEE and WEE viral RNAs by testing geographically and temporally distinct strains of EEE and WEE viruses along with a battery of related and unrelated arthropodborne viruses. In addition, all three types of nucleic acid amplification assays have been used to detect North American EEE and WEE viral RNAs from mosquito and vertebrate tissue samples. The sensitivity, specificity, and rapidity of nucleic acid amplification demonstrate the usefulness of NASBA, standard RT-PCR, and TaqMan assays, in both research and diagnostic settings, to detect North American EEE and WEE viral RNAs. PMID:12517876

  2. Looking for long-term changes in hydroid assemblages (Cnidaria, Hydrozoa) in Alboran Sea (South-Western Mediterranean): a proposal of a monitoring point for the global warming

    NASA Astrophysics Data System (ADS)

    González-Duarte, Manuel María; Megina, Cesar; Piraino, Stefano

    2014-12-01

    In the last 20-30 years, the temperature of the Mediterranean Sea has increased and global warming is allowing the establishment of tropical-affinity species into more temperate zones. Sessile communities are particularly useful as a baseline for ecological monitoring; however, a lack of historical data series exists for sessile marine organisms without commercial interest. Hydroids are ubiquitous components of the benthic sessile fauna on rocky shores and have been used as bio-indicators of environmental conditions. In this study on the benthic hydroid assemblages of the Chafarinas Islands (Alboran Sea, South-Western Mediterranean), we characterized the hydroid assemblages, identified the bathymetric gradients, and compared them with a previous study carried out in 1991. Hydroid assemblages showed a significant difference both between year and among depths. Furthermore, eight species not present in 1991 were found, including two possible new species and the tropical and subtropical species Sertularia marginata. Due to its strategic position at the entrance of the Mediterranean and the existence of previous data on hydroid assemblages, the Chafarinas Islands are proposed as a possible monitoring point for entrance of Atlantic tropical species into the Mediterranean Sea.

  3. Three Centuries of Synchronous Forest Defoliator Outbreaks in Western North America

    PubMed Central

    Flower, Aquila

    2016-01-01

    Insect outbreaks often occur synchronously across large spatial scales, but the long-term temporal stability of the phenomenon and the mechanisms behind it are not well understood. In this study, I use a widespread lepidopteran defoliator native to western North America—the western spruce budworm—as a case study to explore patterns of and potential causes for synchronous population fluctuations. Analyses of synchrony are typically severely limited by the short historical records available for many species. To overcome this limitation, I compiled multi-century dendrochronological reconstructions of western spruce budworm outbreaks from across much of the species’ range. This allowed me to analyze synchrony at a sub-continental spatial scale over the last three centuries. I found statistically significant synchrony among regional outbreak records up to 2,000 km apart and identified numerous outbreak periods that occurred synchronously across much of the species’ range. I quantified spatial and temporal associations between climate and synchronous outbreak periods using paleoclimate reconstructions. The spatial patterns of outbreak histories and climate records were remarkably similar, with higher similarity in outbreak histories apparent between regions with more similar climate conditions. Synchronous outbreaks typically occurred during periods of average or above average moisture availability preceded by periods of low moisture availability. My results suggest that climatic variability has played a key role in synchronizing western spruce budworm population fluctuations in disjunct forests across western North America for at least the last three centuries. Widespread synchrony appears to be a natural part of this species’ population dynamics, though synchronous outbreaks have occurred more frequently during the 20th century than during prior centuries. This study uses a novel combination of statistical methods and dendrochronological data to provide

  4. Hidden diversity and host specificity in cycliophorans: a phylogeographic analysis along the North Atlantic and Mediterranean Sea.

    PubMed

    Obst, Matthias; Funch, Peter; Giribet, Gonzalo

    2005-12-01

    In order to elucidate the evolutionary history and the population structure of the members of the phylum Cycliophora, which live commensally on three species of lobsters, we studied sequence variation in the mitochondrial gene cyctochrome c oxidase subunit I. Overall 242 sequences from 16 locations on both coasts of the North Atlantic, including the North Sea and the Mediterranean, were analysed, revealing 28 haplotypes, with a maximum sequence divergence of 16.6%. Total genetic diversity was high (h = 0.8322, pi = 0.0898), as it was for the commensals on Homarus americanus (17 haplotypes, h = 0.7506, pi = 0.0504). However, it was low for commensals on Nephrops norvegicus (6 haplotypes, h = 0.3899, pi = 0.0035), and intermediate for cycliophorans on Homarus gammarus (5 haplotypes, h = 0.3020, pi = 0.0140). Although two of the host lobsters co-inhabit the coastal waters of Europe, a strong genetic structure (78.45% of the observed genetic variation) was detected among populations on all host species, indicating the existence of a reproductively isolated species on each lobster. In addition, genetic structure over long distances exists among populations on each host species. Such patterns can be explained by the limited dispersal ability of the cycliophoran chordoid larva. Demographic and phylogenetic analyses suggest old and possibly cryptic populations present on H. americanus and H. gammarus, while the latter may have experienced recent bottlenecks, perhaps during Pleistocene glaciations. Populations on N. norvegicus appear to be of recent origin. PMID:16313603

  5. Gulf Stream variability in western North Atlantic off Cape Lookout, North Carolina

    NASA Astrophysics Data System (ADS)

    Pedersen, A. B.; Seidenkrantz, M.-S.; Mienis, F.; Fischel, A.; Frank, N.; Hebbeln, D.

    2012-04-01

    Cold-water coral mounds are common on the SE slope of the US (SEUS) from Florida to Cape Hatteras between depths of 400-600 m. The coral areas lie in the vicinity of the Gulf Stream, which is characterized by strong currents transporting relatively warm water northwards along the SEUS slope. Thus far little is known about the environmental conditions inside the SEUS coral communities and particularly the effects of the nearby Gulf Stream. Near Cape Lookout (North Carolina margin) cold-water corals have formed mound structures, which have a teardrop shape with a sediment tail at the lee side of the mounds, indicating the presence of a strong uni-directional current. The mounds were found to be partly covered with living Lophelia pertusa colonies and partly with sediment and dead coral framework. A 3.4 m long piston core was collected in 2010 during a cruise with the RV Pelagia. This pistoncore was used to determine the changes of the current strength in time in the study area. Different measurements including foraminiferal counts, stable oxygen and carbon isotopes, XRF and magnetic susceptibility were carried out to determine the changes in current strength in the area. Furthermore, cold-water coral fragments were dated with U/Th and foraminifera from the same depth intervals were dated with C14. Datings show that all corals have the same age around 5500 years. However, the sediment in between the corals showed ages ranging between 4700 and 13000 years. Based on the foraminifera data three zones could be observed in the core. Zone 1 ranges between 13000 and 10000 years, zone 2 between 10000-7200 years and zone 3 between 7200-4700 years. These zones all show the gradual onshore movement of the Gulf Stream, that can be related to a rapid rise in sea level as a response to the last deglaciation. This movement has gradually widened the band of the Gulf Stream, thereby compressing the surface and deeper water masses. The strength of the current decreased when fresh water

  6. Prediction of dominant intraseasonal modes in the East Asian-western North Pacific summer monsoon

    NASA Astrophysics Data System (ADS)

    Oh, Hyoeun; Ha, Kyung-Ja

    2016-10-01

    Intraseasonal monsoon prediction is the most imperative task, but there remains an enduring challenge in climate science. The present study aims to provide a physical understanding of the sources for prediction of dominant intraseasonal modes in the East Asian-western North Pacific summer monsoon (EA-WNPSM): pre-Meiyu&Baiu, Changma&Meiyu, WNPSM, and monsoon gyre modes classified by the self-organizing map analysis. Here, we use stepwise regression to determine the predictors for the four modes in the EA-WNPSM. The selected predictors are based on the persistent and tendency signals of the sea surface temperature (SST)/2m air temperature and sea level pressure fields, which reflect the asymmetric response to the El Niño Southern Oscillation (ENSO) and the ocean and land surface anomalous conditions. For the pre-Meiyu&Baiu mode, the SST cooling tendency over the western North Pacific (WNP), which persists into summer, is the distinguishing contributor that results in strong baroclinic instability. A major precursor for the Changma&Meiyu mode is related to the WNP subtropical high, induced by the persistent SST difference between the Indian Ocean and the western Pacific. The WNPSM mode is mostly affected by the Pacific-Japan pattern, and monsoon gyre mode is primarily associated with a persistent SST cooling over the tropical Indian Ocean by the preceding ENSO signal. This study carries important implications for prediction by establishing valuable precursors of the four modes including nonlinear characteristics.

  7. Prediction of dominant intraseasonal modes in the East Asian-western North Pacific summer monsoon

    NASA Astrophysics Data System (ADS)

    Oh, Hyoeun; Ha, Kyung-Ja

    2015-12-01

    Intraseasonal monsoon prediction is the most imperative task, but there remains an enduring challenge in climate science. The present study aims to provide a physical understanding of the sources for prediction of dominant intraseasonal modes in the East Asian-western North Pacific summer monsoon (EA-WNPSM): pre-Meiyu&Baiu, Changma&Meiyu, WNPSM, and monsoon gyre modes classified by the self-organizing map analysis. Here, we use stepwise regression to determine the predictors for the four modes in the EA-WNPSM. The selected predictors are based on the persistent and tendency signals of the sea surface temperature (SST)/2m air temperature and sea level pressure fields, which reflect the asymmetric response to the El Niño Southern Oscillation (ENSO) and the ocean and land surface anomalous conditions. For the pre-Meiyu&Baiu mode, the SST cooling tendency over the western North Pacific (WNP), which persists into summer, is the distinguishing contributor that results in strong baroclinic instability. A major precursor for the Changma&Meiyu mode is related to the WNP subtropical high, induced by the persistent SST difference between the Indian Ocean and the western Pacific. The WNPSM mode is mostly affected by the Pacific-Japan pattern, and monsoon gyre mode is primarily associated with a persistent SST cooling over the tropical Indian Ocean by the preceding ENSO signal. This study carries important implications for prediction by establishing valuable precursors of the four modes including nonlinear characteristics.

  8. Effects of a Warmer Climate on Stress Complexes in Forests of Western North America

    NASA Astrophysics Data System (ADS)

    Peterson, D. L.; McKenzie, D.; Littell, J.

    2005-12-01

    A warmer climate in western North America will first affect those forests that are most susceptible to soil moisture stress. Increased water deficit will accelerate the normal stress complex experienced in forests, which typically involves some combination of multi-year drought, insects, and fire. Symptoms of prolonged drought and insects are currently manifested in extensive dieback of pine species in the pinyon-juniper forest of the American Southwest, an area where only a few tree species can survive. Less severe dieback has occurred in mixed conifer forests of the Sierra Nevada, an area also subjected to air pollution stress. Bark beetles are proliferating and killing millions of hectares of dry forest in the northern interior of western North America, setting up the prospect of large and intense fires. Recent analyses of area burned by fire in the 11 large Western states of the conterminous United States indicate that fire area will be at least twice as high in the warmer climate predicted by general circulation models. Such a large increase in disturbance superimposed on forests with increased stress from drought and insects may have significant effects on growth, regeneration, and long-term distribution and abundance of forest species.

  9. Molecular and pathogenic variation within Melampsora on Salix in western North America reveals numerous cryptic species.