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Auteur BOAVIDA, J.; PAULO, D.; AURELLE, D.; ARNAUD-HAOND, S.; MARSCHAL, C.; REED, J.; GONCALVES, J.M.S.; SERRAO, E.A. url  doi
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  Titre A Well-Kept Treasure at Depth: Precious Red Coral Rediscovered in Atlantic Deep Coral Gardens (SW Portugal) after 300 Years Type Article scientifique
  Année (down) 2016 Publication Revue Abrégée Plos One  
  Volume 11 Numéro 1 Pages  
  Mots-Clés  
  Résumé Background The highly valuable red coral Corallium rubrum is listed in several Mediterranean Conventions for species protection and management since the 1980s. Yet, the lack of data about its Atlantic distribution has hindered its protection there. This culminated in the recent discovery of poaching activities harvesting tens of kg of coral per day from deep rocky reefs off SW Portugal. Red coral was irregularly exploited in Portugal between the 1200s and 1700s, until the fishery collapsed. Its occurrence has not been reported for the last 300 years. Results Here we provide the first description of an Atlantic red coral assemblage, recently rediscovered dwelling at 60-100 m depth in southern Portugal. We report a very slow growth rate (0.23 mm year-1), comparable to Mediterranean specimens. In comparison with most of the Mediterranean reports, the population reaches much larger sizes, estimated to be over one century old, and has a more complex coral branch architecture that promotes a rich assemblage of associated species, with boreal and Mediterranean affinities. Atlantic red coral is genetically distinct, yet mitochondrial analyses suggest that red corals from the Atlantic may have introgressed the Mediterranean ones after migration via the Algeria current. Our underwater surveys, using advanced mixed-gas diving, retrieved lost fishing gear in all coral sites. Besides illegal harvesting, the use and loss of fishing gears, particularly nets, by local fisheries are likely sources of direct impacts on these benthic assemblages. Conclusions We extended the knowledge on the distribution of C. rubrum in the Atlantic, discovered its genetic distinctiveness, and reveal a rich deep-dwelling fauna associated to these coral assemblages. These findings support a barrier role of the Atlantic-Mediterranean transition zone, but reveal also hints of connectivity along its southern margin. The results highlight the genetic and demographic uniqueness of red coral populations from SW Iberia. However, we also report threats to these vulnerable populations by direct and indirect fishing activities and argue that its protection from any mechanically destructive activities is urgent as a precautionary approach. This study advances our understanding of phylogeographic barriers and range edge genetic diversity, and serves as a baseline against which to monitor future human and environmental disturbances to Atlantic C. rubrum.  
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  ISSN 1932-6203 ISBN Médium  
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  Numéro d'Appel MARBEC @ isabelle.vidal-ayouba @ collection 1513  
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Auteur Keller, S.; BARTOLINO, V.; HIDALGO, M.; BITETTO, I.; CASCIARO, L.; CUCCU, D.; ESTEBAN, A.; GARCIA, C.; GAROFALO, G.; JOSEPHIDES, M.; JADAUD, A.; LEFKADITOU, E.; MAIORANO, P.; MANFREDI, C.; MARCETA, B.; MASSUT, E.; MICALLEF, R.; PERISTERAKI, P.; RELINI, G.; SARTOR, P.; SPEDICATO, M.T.; TSERPES, G.; QUETGLAS, A. url  doi
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  Titre Large-scale spatio-temporal patterns of Mediterranean cephalopod diversity Type Article scientifique
  Année (down) 2016 Publication Revue Abrégée Plos One  
  Volume 11 Numéro 1 Pages  
  Mots-Clés  
  Résumé Species diversity is widely recognized as an important trait of ecosystems’ functioning and resilience. Understanding the causes of diversity patterns and their interaction with the environmental conditions is essential in order to effectively assess and preserve existing diversity. While diversity patterns of most recurrent groups such as fish are commonly studied, other important taxa such as cephalopods have received less attention. In this work we present spatio-temporal trends of cephalopod diversity across the entire Mediterranean Sea during the last 19 years, analysing data from the annual bottom trawl survey MEDITS conducted by 5 different Mediterranean countries using standardized gears and sampling protocols. The influence of local and regional environmental variability in different Mediterranean regions is analysed applying generalized additive models, using species richness and the Shannon Wiener index as diversity descriptors. While the western basin showed a high diversity, our analyses do not support a steady eastward decrease of diversity as proposed in some previous studies. Instead, high Shannon diversity was also found in the Adriatic and Aegean Seas, and high species richness in the eastern Ionian Sea. Overall diversity did not show any consistent trend over the last two decades. Except in the Adriatic Sea, diversity showed a hump-shaped trend with depth in all regions, being highest between 200-400 m depth. Our results indicate that high Chlorophyll a concentrations and warmer temperatures seem to enhance species diversity, and the influence of these parameters is stronger for richness than for Shannon diversity.  
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  Numéro d'Appel MARBEC @ isabelle.vidal-ayouba @ collection 1517  
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Auteur Garavelli, L.; Colas, F.; Verley, P.; Kaplan, D.M.; Yannicelli, B.; Lett, C. url  doi
openurl 
  Titre Influence of Biological Factors on Connectivity Patterns for Concholepas concholepas (loco) in Chile Type Article scientifique
  Année (down) 2016 Publication Revue Abrégée Plos One  
  Volume 11 Numéro 1 Pages e0146418  
  Mots-Clés Biological transport; Biophysics; Chile (country); Death rates; Fecundity; Hydrodynamics; Larvae; Marine biology  
  Résumé In marine benthic ecosystems, larval connectivity is a major process influencing the maintenance and distribution of invertebrate populations. Larval connectivity is a complex process to study as it is determined by several interacting factors. Here we use an individual-based, biophysical model, to disentangle the effects of such factors, namely larval vertical migration, larval growth, larval mortality, adults fecundity, and habitat availability, for the marine gastropod Concholepas concholepas (loco) in Chile. Lower transport success and higher dispersal distances are observed including larval vertical migration in the model. We find an overall decrease in larval transport success to settlement areas from northern to southern Chile. This spatial gradient results from the combination of current direction and intensity, seawater temperature, and available habitat. From our simulated connectivity patterns we then identify subpopulations of loco along the Chilean coast, which could serve as a basis for spatial management of this resource in the future.  
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  Numéro d'Appel MARBEC @ alain.herve @ collection 1534  
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Auteur De Wit, R.; Gautret, P.; Bettarel, Y.; Roques, C.; Marlière, C.; Ramonda, M.; Nguyen Thanh, T.; Tran Quang, H.; Bouvier, T. url  doi
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  Titre Viruses Occur Incorporated in Biogenic High-Mg Calcite from Hypersaline Microbial Mats Type Article scientifique
  Année (down) 2015 Publication Revue Abrégée PLoS ONE  
  Volume 10 Numéro 6 Pages e0130552  
  Mots-Clés  
  Résumé Using three different microscopy techniques (epifluorescence, electronic and atomic force microscopy), we showed that high-Mg calcite grains in calcifying microbial mats from the hypersaline lake “La Salada de Chiprana”, Spain, contain viruses with a diameter of 50–80 nm. Energy-dispersive X-ray spectrometer analysis revealed that they contain nitrogen and phosphorus in a molar ratio of ~9, which is typical for viruses. Nucleic acid staining revealed that they contain DNA or RNA. As characteristic for hypersaline environments, the concentrations of free and attached viruses were high (>1010 viruses per g of mat). In addition, we showed that acid treatment (dissolution of calcite) resulted in release of viruses into suspension and estimated that there were ~15 × 109 viruses per g of calcite. We suggest that virus-mineral interactions are one of the possible ways for the formation of nano-sized structures often described as “nanobacteria” and that viruses may play a role in initiating calcification.  
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  Numéro d'Appel MARBEC @ alain.herve @ collection 1283  
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Auteur Bertrand, S.; Joo, R.; Fablet, R. url  doi
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  Titre Generalized Pareto for Pattern-Oriented Random Walk Modelling of Organisms’ Movements Type Article scientifique
  Année (down) 2015 Publication Revue Abrégée PLoS ONE  
  Volume 10 Numéro 7 Pages e0132231  
  Mots-Clés  
  Résumé How organisms move and disperse is crucial to understand how population dynamics relates to the spatial heterogeneity of the environment. Random walk (RW) models are typical tools to describe movement patterns. Whether Lévy or alternative RW better describes forager movements is keenly debated. We get around this issue using the Generalized Pareto Distribution (GPD). GPD includes as specific cases Normal, exponential and power law distributions, which underlie Brownian, Poisson-like and Lévy walks respectively. Whereas previous studies typically confronted a limited set of candidate models, GPD lets the most likely RW model emerge from the data. We illustrate the wide applicability of the method using GPS-tracked seabird foraging movements and fishing vessel movements tracked by Vessel Monitoring System (VMS), both collected in the Peruvian pelagic ecosystem. The two parameters from the fitted GPD, a scale and a shape parameter, provide a synoptic characterization of the observed movement in terms of characteristic scale and diffusive property. They reveal and quantify the variability, among species and individuals, of the spatial strategies selected by predators foraging on a common prey field. The GPD parameters constitute relevant metrics for (1) providing a synthetic and pattern–oriented description of movement, (2) using top predators as ecosystem indicators and (3) studying the variability of spatial behaviour among species or among individuals with different personalities.  
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  Numéro d'Appel MARBEC @ isabelle.vidal-ayouba @ collection 1325  
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