Éditeur(s) : HAL CCSD
Résumé : Designing biodiversity conservation plans requires knowledge on the biogeographic distribution of taxabut also accurate estimates of species richness and diversification processes. However, measuring the phyleticrichness can be biased by the use of inappropriate taxonomical characters, leading to erroneous speciesdelimitation and diversity estimates.This work explores the phyletic richness at several taxonomic levels (generic, specific and intraspecific) ofthe hydrozoan family Aglaopheniidae (Marktanner-Turneretscher, 1890), with a particular focus on the South-Western Indian Ocean. Firstly, using several newly constructed phylogenies based on mitochondrial andnuclear markers, this study reveals that the phyletic diversity of this family is at underestimated by at least 50%:all studied genera are polyphyletic or with doubtful monophyletic status. Then, using several speciesdelimitation methods based on molecular markers, it sheds light on the richness of cryptic diversity of thisfamily, enlightening the potential of using an integrative taxonomic approach on these morphologically simpleorganisms. Finally, the population genetics of an Aglaopheniidae brooding species shows a high populationsstructuring with pervasive pattern of isolation by distance at several geographic scales (several to thousands ofkilometres), implying a potentially high cryptic diversity existing in this family.The results of this work provide new insights on Aglaopheniidae diversity, underlining the potentialinfluence of reproductive mode on the phyletic diversity and diversification processes of brooding hydrozoanbrooders. This thesis further highlights the relevance of using several complementary
La conservation et la gestion sur le long terme de la biodiversité nécessitent une connaissance de larépartition des taxons, mais également une estimation précise de leur diversité spécifique ainsi que desprocessus de spéciation ayant permis leur formation. Cependant, la mesure de la richesse phylétique peut êtrebiaisée par l’utilisation de caractères taxinomiques ne permettant pas de délimiter les espèces de manièreappropriée.Ce travail de thèse propose d’explorer la diversité phylétique à plusieurs niveaux taxinomiques(générique, spécifique et intra-spécifique) des Aglaopheniidae, une famille d’hydrozoaires, notamment présentedans le Sud-Ouest de l’océan Indien. Dans un premier temps, en utilisant des phylogénies basées sur plusieursmarqueurs (mitochondriaux et nucléaires), ce travail démontre que la diversité phylétique de cette famille est,au minimum, sous-estimée de moitié: tous les genres de la famille sont polyphyléthiques ou présentent un statutmonophylétique restant à confirmer. Dans un deuxième temps, l’utilisation de méthodes de délimitationd’espèces basées sur des données moléculaires met en évidence la diversité cryptique très élevée des morphoespècesétudiées, révélant l’intérêt potentiel des protocoles de taxinomie intégrative chez les organismesmorphologiquement simples. Enfin, l’étude de génétique des populations d’une espèce incubatriced’Aglaopheniidae révèle l’importance de la structuration des populations et de l’isolement par la distance chezcette espèce à plusieurs échelles géographiques (de quelques kilomètres à plusieurs milliers), impliquant unepotentielle diversité cryptique extrêmement élevée chez cette famille.L’ensemble des connaissances acquises lors de ce travail de thèse fournit un nouveau regard sur ladiversité de la famille des Aglaopheniidae, soulignant le potentiel impact du cycle de reproduction sur ladiversité phylétique et les processus de spéciation des hydrozoaires incubateurs. Cette thèse met en évidence lapertinence de l’utilisation de plusieurs procédures complémentaires de délimitation d’espèces pour étudier ladiversité des organismes morphologiquement simples.
https://hal.archives-ouvertes.fr/tel-01359424

tel-01359424
https://hal.archives-ouvertes.fr/tel-01359424
https://hal.archives-ouvertes.fr/tel-01359424/document
https://hal.archives-ouvertes.fr/tel-01359424/file/These%20manuscrit%20final.pdf

Éditeur(s) : Academic Press Inc Elsevier Science
Résumé : Several Vibrio species are known to be pathogenic to the Pacific oyster Crassostrea gigas. Survival varies according to pathogen exposure and high mortality events usually occur in summer during gametogenesis. In order to study the effects of gametogenetic status and ploidy (a factor known to affect reproduction allocation in oysters) on vibriosis survival, we conducted two successive experiments. Our results demonstrate that a common bath challenge with pathogenic Vibrio splendidus and Vibrio aestuarianus on a mixture of mature, spawning and non-mature oysters can lead to significant mortality. Previous bath challenges, which were done using only non-mature oysters, had not produced mortality. Immunohisto-chemical analyses showed the affinity of Vibrio for gonadic tissues, highlighting the importance of sexual maturity for vibriosis infection processes in oysters. Mortality rate results showed poor repeatability between tanks, however, in this bath challenge. We then tested a standardized and repeatable injection protocol using two different doses of the same combination of two Vibrio species on related diploid and triploid oysters at four different times over a year. Statistical analyses of mortality kinetics over a 6-day period after injection revealed that active gametogenesis periods correspond to higher susceptibility to vibriosis and that there is a significant interaction of this seasonal effect with ploidy. However, no significant advantage of triploidy was observed. Triploid oysters even showed lower survival than diploid counterparts in winter. Results are discussed in relation to differing energy allocation patterns between diploid and triploid Pacific oysters. (C) 2010 Elsevier Inc. All rights reserved.
Journal Of Invertebrate Pathology (0022-2011) (Academic Press Inc Elsevier Science), 2011-02 , Vol. 106 , N. 2 , P. 179-191

Droits : 2010 Elsevier Inc. All rights reserved.
http://archimer.ifremer.fr/doc/00030/14108/11368.pdf
DOI:10.1016/j.jip.2010.09.003
http://archimer.ifremer.fr/doc/00030/14108/

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
Tropical islands are characterized by thermal and orographical forcings which may generate microscale air mass circulations. The Lesser Antilles Arc includes small tropical islands (width lower than 50 km) where a total of one-and-a-half million people live. Air quality over this region is affected by anthropogenic and volcanic emissions, or saharan dust. To reduce risks for the population health, the atmospheric dispersion of emitted pollutants must be predicted. In this study, the dispersion of anthropogenic nitrogen oxides (NOx) is numerically modelled over the densely populated area of the Guadeloupe archipelago under weak trade winds, during a typical case of severe pollution. The main goal is to analyze how microscale resolutions affect air pollution in a small tropical island. Three resolutions of domain grid are selected: 1 km, 333 m and 111 m. The Weather Research and Forecasting model (WRF) is used to produce real nested microscale meteorological fields. Then the weather outputs initialize the Lagrangian Particle Dispersion Model (FLEXPART). The forward simulations of a power plant plume showed good ability to reproduce nocturnal peaks recorded by an urban air quality station. The increase in resolution resulted in an improvement of model sensitivity. The nesting to subkilometer grids helped to reduce an overestimation bias mainly because the LES domains better simulate the turbulent motions governing nocturnal flows. For peaks observed at two air quality stations, the backward sensitivity outputs identified realistic sources of NOx in the area. The increase in resolution produced a sharper inverse plume with a more accurate source area. This study showed the first application of the FLEXPART-WRF model to microscale resolutions. Overall, the coupling model WRF-LES-FLEXPART is useful to simulate the pollutant dispersion during a real case of calm wind regime over a complex terrain area. The forward and backward simulation results showed clearly that the subkilometer resolution of 333 m is necessary to reproduce realistic air pollution patterns in this case of short-range transport over a complex terrain area. Globally, this work contributes to enrich the sparsely documented domain of real nested microscale air pollution modelling. This study dealing with the determination of the proper resolution grid and proper turbulence scheme, is of significant interest to the near-source and complex terrain air quality research community.
ISSN: 1352-2310

hal-01349208
https://hal.archives-ouvertes.fr/hal-01349208
DOI : 10.1016/j.atmosenv.2016.05.028

Éditeur(s) : HAL CCSD Elsevier
Résumé : We have studied the phase transformation of forsterite to wadsleyite under shear stress at the Earth's transition zone pressure and temperature conditions. Two-step experiments were performed using a multi-anvil press. First, we hot pressed iron-free forsterite at 6 or 11 GPa and 1100 degrees C. Then we deformed a slab of this starting material using a direct simple shear assembly at 16 GPa and 1400 degrees C for 1, 15, 35, 40, or 60 min. Both the starting material and the deformed samples were characterized using optical and scanning electron microscopy including measurements of crystal preferred orientations (CPO) by electron back scattered diffraction (EBSD), transmission electron microscopy (TEM), and Fourier transform infrared spectroscopy (FTIR). The phase transformation occurs very rapidly, in less than 1 min, and metastable forsterite relics are not observed after deformation. The grain size of wadsleyite is slightly smaller than the forsterite starting material. The water contents obtained from FTIR analyses in forsterite and wadsleyite are 65-124 wt ppm H2O and 114-736 wt ppm H2O, respectively, which are well below water solubility at similar conditions in the presence of free water. Wadsleyite aggregates display weak CPO patterns with [1 0 0] axes concentrated at low angle to the shear direction, [0 1 0] axes perpendicular to the shear plane and nearly random [0 0 1] axes. Only a few dislocations were observed in wadsleyite with TEM. This observation is consistent with the assumption that most dislocations formed during the initial high-stress stages of these stress-relaxation experiments, were consumed in the phase transformation, probably enhancing the transformation rate. CPO patterns vary as a function of the water content: with increasing water content the density of [1 0 0] axes parallel to the shear direction decreases, and the density of [0 0 1] axes increases. Viscoplastic self-consistent modeling of CPO evolution using previously reported glide systems for wadsleyite, i.e., [1 0 0]{0 k 1} and 1/2 (1 1 1){1 0 1}, cannot reproduce the measured CPO, unless the [0 0 1](0 1 0) system, for which dislocations have not been observed by TEM, is also activated. In addition, wadsleyite grain growth suggests the participation of diffusion-assisted processes in deformation. Calculated anisotropies for P and S-waves using measured CPO are always below 1%. This very low anisotropy is due to both the low finite strain achieved in the experiments, which leads to weak wadsleyite CPO, and to the diluting effect of added majorite. The present experiments emphasize the importance of stress, grain size evolution and water content in the forsterite to wadsleyite phase transformation and subsequent deformation in the transition zone.
ISSN: 0031-9201

hal-00617430
https://hal.archives-ouvertes.fr/hal-00617430
DOI : 10.1016/j.pepi.2010.11.001

Éditeur(s) : HAL CCSD Cambridge University Press
Résumé : International audience
The reproduction of Rhinecanthus aculeatus (Linnaeus,1758), a tropical Indo-Pacific reef fish, occurs aroundthe full and new moon (Kuwamura 1997). Spawningbegins 16 to 45 min before the sunrise. The courtshipsbegin 7 to 27 min before the spawning. A specific behaviourof the courtships is when the male places itsrostrum against the caudal peduncle of the female(Kuwamura 1997).Observations have been recorded in the lagoon ofTiahura [shallow sandy area (0.5 - 2 m deep) withalgae Hypnea spinella (C.Agardh) Kützing, 1847 -Moorea, French Polynesia; 17°29′27′ S, 149°53′32″O]in March and April 2015. Fifteen R. aculeatus (fivemales and ten females) lived in this area where themales have territories, which included the subterritoriesof the females. During video-recorded courtships,in addition to the behaviour described byKuwamura (the nuzzling), two new behaviours havebeen observed: circling and touching. During the circling,the male and the female swim to the surface inprogressively larger circles (Fig. 1). The circling behaviourhas been observed in other Balistidae such asPseudobalistes flavimarginatus (Rüppell, 1829) andBalistapus undulatus (Park, 1797) (Lobel andJohannes 1980). During the touching, the abdomensof the male and the female’s touch each other withoutgametes emission (Fig. 2). The touching has been reportedfor Xanthichthys mento (Jordan and Gilbert1882) (Kawase 2003).Although Balistidae present different reproductivestrategies, they have common reproduction features,such as the time and the day of hatching andspawning (Kawase 2003). Our observations are innovativebecause the courtship of R. aculeatus is morecomplicated than previously described. This resultsuggests, thus, that Balistidae have also some commoncourtship behaviour features. These behaviours mayfacilitate the release of gametes, as with the nuzzling(Kuwamura 1997) or can convince the partner to mate.We do not know if these patterns are phylogeneticallyrelated. But as the egg care strategy of Balistidae (biparentalvs maternal) appears to be related to the distributionof food and breeding sites, more than by thephylogeny (Kuwamura 1997), more studies on thistopic will be useful to better understand the establishement of these behaviours.
EISSN: 1755-2672

hal-01562097
https://hal-univ-perp.archives-ouvertes.fr/hal-01562097
DOI : 10.1007/s12526-016-0464-7

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
In fold and thrust belts drainage organization and patterns of sedimentation depend conceptually on the ability or not for preexisting reaches to incise uplifting thrust sheets. In this study we investigate experimentally the dynamics of drainage network in a wedge submitted to shortening and erosion. It allows us to reproduce and to monitor the interactions between tectonics, erosion and sedimentation during the development of up to five successive thrust sheets. In the experiments channels adjust to uplift rate by both increasing their slope and narrowing their channels as it is observed in nature. The series of experiments shows that the proportion of persistent preexisting transverse channels increases with the ratio of rainfall over shortening rates. The experiments confirm the view that the competition between discharge and tectonic uplift controls along-strike variations in sediment flux in sedimentary basins by controlling the drainage organization. If the transverse channels draining a wedge are not diverted, a line-source dispersal system develops in front of the active structure. If channels are diverted in the backlimb of the frontal structure it results in point-sourced depositional systems separated by areas fed only by small channels developing in the front of the wedge. Fans accumulated in front of the active structures reveal two stages of sedimentation, one of progradation, while the frontal structure is active and a second one of valley backfilling and thrust sealing during internal deformation of the wedge. The experiments also suggest that spatial variations in rock uplift rate along a thrust front may be evidenced by minimum-discharge variations of persistent transverse channels.
ISSN: 0040-1951

insu-01252482
https://hal-insu.archives-ouvertes.fr/insu-01252482
DOI : 10.1016/j.tecto.2015.09.007

Éditeur(s) : HAL CCSD BioScientifica
Résumé : International audience
The general rules established from mammalian species for the regulation of spermatogenesis by gonadotropins may not be fully relevant in fish. Particularly, Fsh is as potent as Lh to stimulate steroidogenesis and the Fsh receptor is expressed in Leydig cells. In seasonal breeders, Fsh is likely the major gonadotropin involved in spermatogenesis onset and Lh is required to support spermatogenesis progression and gamete release. However, the genes that relay the action of Fsh and Lh have been poorly investigated in fish. The present study was aimed at identifying gonadotropin-dependent genes expressed in the testis during fish puberty. We cultured pubertal trout testicular explants for 96 h, with or without gonadotropin, and analyzed transcriptome variations using microarrays. Fsh and Lh had similar effects on a large group of genes while other genes were preferentially regulated by one or the other gonadotropin. We showed that most of the responsive genes were expressed in somatic cells and exhibited relevant patterns during the seasonal reproductive cycle. Some genes preferentially modulated by Lh could be involved in testicular cell fate (pvrl1 and bty) or sperm maturation (ehmt2 and racgap1) and will deserve further examination. Besides Fsh's effects on the steroidogenic pathway, our study demonstrates that Fsh coordinates relevant stimulatory and inhibitory paracrine factors known to regulate early germ cell proliferation and differentiation. Some of these genes belong to major regulatory pathways including the Igf pathway (igf1b/igf3 and igfbp6), the Tgfb pathway (amh, inha, inhba, and fstl3), the Wnt pathway (wisp1), and pleiotrophin (mdka).
ISSN: 0952-5041

inserm-00812401
http://www.hal.inserm.fr/inserm-00812401
DOI : 10.1530/JME-12-0197
PUBMED : 23045716

Éditeur(s) : HAL CCSD Public Library of Science
Résumé : International audience
Patterns of connectivity and self-recruitment are recognized as key factors shaping the dynamics of marine populations. Connectivity is also essential for maintaining and restoring natural ecological processes with genetic diversity contributing to the adaptation and persistence of any species in the face of global disturbances. Estimates of connectivity are crucial to inform the design of both marine protected areas (MPAs) and MPA networks. Among several approaches, genetic structure is frequently used as a proxy for patterns of connectivity. Using 8 microsatellite loci, we investigated genetic structure of the two-banded sea bream Diplodus vulgaris, a coastal fish that is both commercially and ecologically important. Adults were sampled in 7 locations (stretches of coastline approximately 8 km long) and juveniles in 14 sites (~100 to 200 m of coastline) along 200 km of the Apulian Adriatic coast (SW Adri-atic Sea), within and outside an MPA (Torre Guaceto MPA, Italy). Our study found similar genetic diversity indices for both the MPA and the surrounding fished areas. An overall lack of genetic structure among samples suggests high gene flow (i.e. connectivity) across a scale of at least 200 km. However, some local genetic divergences found in two locations demonstrate some heterogeneity in processes renewing the population along the Apulian Adriatic coast. Furthermore, two sites appeared genetically divergent, reinforcing our observations within the genetic makeup of adults and confirming heterogeneity in early stage genetics that can come from either different supply populations or from chaotic genetic patchiness occurring under temporal variation in recruitment and in the reproductive success. While the specific role of the MPA is not entirely known in this case, these results confirm the presence of regional processes and the key role of connectivity in maintaining the local population supply.
ISSN: 1932-6203

hal-01442055
https://hal-univ-perp.archives-ouvertes.fr/hal-01442055
https://hal-univ-perp.archives-ouvertes.fr/hal-01442055/document
https://hal-univ-perp.archives-ouvertes.fr/hal-01442055/file/journal.pone.0167441.pdf
DOI : 10.1371/journal.pone.0167441.s009

Éditeur(s) : Cushman Foundation for Foraminiferal Research
Résumé : The objectives of this study were to observe foraminiferal colonization patterns and behavior in shrimp ponds in New Caledonia during a shrimp-growing (farming) cycle. Weekly collecting at 10 stations in 8 shrimp ponds yielded a total of 170 samples accompanied by environmental data. Seawater pumped from the nearby ocean filled the ponds at the beginning of the growth cycle and its daily renewal maintained salinity at 32-39, and supplied the ponds with influxes of smaller, mostly juvenile, foraminifera. A few days after initial filling, the pioneering species Ammonia tepida and Quinqueloculina seminula appeared, with A. tepida dominant. Their high reproduction rates increased both living and dead assemblage densities during the first 10 weeks. Populations of these two species then stabilized with higher oxygen demand (drop of redox) and consumption of living foraminifera by shrimp. Only a few colonizers subsequently appeared, which was attributed to the isolation of the pond, despite the high rate of water renewal. Only one pond had notably higher species richness, but it could not be distinguished from the others by its physicochemical parameters. The species that appeared in ponds initially barren of foraminifera also survived where there was water seepage between growing cycles, suggesting that the assemblages had already reached equilibrium with the environment. Despite the number of environmental parameters measured, only oxygen and reactive organic matter correlated with the microfauna on a weekly timescale. We assume that other parameters do not significantly affect foraminifera until they reach critical threshold. Consistent with previous studies, A. tepida was the species most tolerant of organic influx, but its relative abundance dropped once the organic matter flocculated and settled, leading to disoxic conditions in the sediment. Conversely, Q. seminula was able to climb through the floc and reach the oxygenated layer, where its relative abundance increased.
Journal of Foraminiferal Research (0096-1191) (Cushman Foundation for Foraminiferal Research), 2009-10 , Vol. 39 , N. 4 , P. 249-266

Droits : 2009 Cushman Foundation for Foraminiferal Research
http://archimer.ifremer.fr/doc/2009/publication-6954.pdf
DOI:10.2113/gsjfr.39.4.249
http://archimer.ifremer.fr/doc/00000/6954/

Éditeur(s) : Academic Press Ltd- Elsevier Science Ltd
Résumé : Several empirical and theoretical studies have shown how the exploitation of food sources, the choice of resting sites or other types of collective decision-making in heterogeneous environments are facilitated and modulated by social interactions between conspecifics. It is well known that many pelagic fishes live in schools and that this form of gregarious behavior provides advantages in terms of food intake and predator avoidance efficiency. However, the influence of social behavior in the formation of aggregations by tuna under floating objects (FOBs) is poorly understood. In this work, we investigated the collective patterns generated by different theoretical models, which either include or exclude social interactions between conspecifics, in the presence of two aggregation sites. The resulting temporal dynamics and distributions of populations were compared to in situ observations of tuna behavior. Our work suggests that social interactions should be incorporated in aggregative behavior to reproduce the temporal patterns observed in the field at both the individual and the group level, challenging the common vision of tuna aggregations around FOBs. Our study argues for additional data to further demonstrate the role of social behavior in the dynamics of these fish aggregations. Understanding the interplay between environmental and social factors in the associative behavior of fish with FOBs is necessary to assess the consequences of the widespread deployment of artificial FOBs by fishermen.
Journal Of Theoretical Biology (0022-5193) (Academic Press Ltd- Elsevier Science Ltd), 2014-10 , Vol. 359 , P. 161-170

Droits : 2014 Elsevier Ltd. All rights reserved.
http://archimer.ifremer.fr/doc/00195/30638/29091.pdf
DOI:10.1016/j.jtbi.2014.06.010
http://archimer.ifremer.fr/doc/00195/30638/

Éditeur(s) : Pergamon-elsevier Science Ltd
Résumé : Climate may act on the dispersal and connectivity of marine populations through changes in the oceanic circulation and temperature, and by modifying species' prey and predator distributions. As dispersal and connectivity remain difficult to assess in situ, a first step in studying the effects of climate change can be achieved using biophysical models. To date, only a few biophysical models have been used for this purpose. Here we review these studies and also include results from other recent modelling efforts. We show that increased sea temperature, a major change expected under climate warming, may impact dispersal and connectivity patterns via changes in reproductive phenology (e.g., shift in the spawning season), transport (e.g., reduced pelagic larval duration under faster development rates), mortality (e.g., changes in the exposure to lethal temperatures), and behaviour (e.g.. increased larval swimming speed). Projected changes in circulation are also shown to have large effects on the simulated dispersal and connectivity patterns. Although these biophysical modelling studies are useful preliminary approaches to project the potential effects of climate change, we highlight their current limitations and discuss the way forward, in particular the need for adequate coupled hydrodynamic-biogeochemical simulations using atmospheric forcing from realistic climate change scenarios. (C) 2010 Elsevier Ltd. All rights reserved.
Progress In Oceanography (0079-6611) (Pergamon-elsevier Science Ltd), 2010-10 , Vol. 87 , N. 1-4 , P. 106-113

Droits : 2010 Elsevier Ltd All rights reserved.
http://archimer.ifremer.fr/doc/00031/14176/11522.pdf
DOI:10.1016/j.pocean.2010.09.005
http://archimer.ifremer.fr/doc/00031/14176/

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
We have inferred the deformation mechanisms of antigorite by high-resolution EBSD mapping of samples from Cerro del Almirez ultramafic massif (Betic Cordillera, SE Spain). Textural relations and phase diagram calculations constrain the foliation development conditions to the subduction prograde path at up to 600-630 °C and 1.6-1.9 GPa. Deformation was followed by static annealing of antigorite at ca. 680 °C. The Crystal Preferred Orientation (CPO) of antigorite is characterised by a strong alignment of (001) poles normal to the foliation plane and a weaker, but clear, parallelism between [100] axes and the macroscopic lineation defined by the elongation of magnetite aggregates. Analysis of misorientations across subgrains shows predominance of [010] rotation axis, consistent with activation of the [100](001) slip system. However, tilt subgrain boundaries subparallel to (100), probably formed by edge dislocations of this system, are subsidiary. Most subgrain boundaries are subparallel to (001) planes. They are interpreted as (001) twins wherein continuing viscoplastic deformation resulted in a slight increase of the misorientation between the twins. Modelling of the evolution of the antigorite CPO using a lower bound approach and considering different deformation regimes and sets of basal and non-basal slip systems has shown that intensities of [100] and [010] maxima reflect the relative strength of the antigorite [100](001) and [010](001) systems. Activation of other basal or non-basal slip systems does not change significantly the CPO patterns, but results in less concentrated CPO. 3D transpression models better reproduce the CPO of natural antigorite serpentinites. We propose that the widespread occurrence of strong CPO in high-pressure antigorite serpentinite is consistent with deformation by dislocation creep with dominant glide on [hk0](001), together with the activation of twinning, implying that a power law rheology would better account for the mechanical behaviour of antigorite serpentinite deep in the subduction channel and mantle wedge.
ISSN: 0012-821X

hal-00795511
https://hal.archives-ouvertes.fr/hal-00795511
DOI : 10.1016/j.epsl.2012.06.049

Éditeur(s) : Elsevier
Résumé : The present work is based on a set of bottom trawl surveys performed in the Gulf of Lions between 1983 and 1992. A new method which couples the STATIS multitable approach with the logic of correspondence analysis (CoA) is proposed to study the stability of spatial organization of demersal assemblages in terms of species composition. This CoA version of STATIS has provided a clear representation of the stable part of the spatial structure of the assemblages. In addition, it gave an insight into the interannual variations of the distribution of each population around the reference structure. Our results showed that the demersal assemblages of the Gulf of Lions exhibited strong spatial structuring, mainly orientated along a bathymetric gradient. This gradient is structured around three major regions: the coast, the continental shelf and the continental slope. Despite sampling variations that occurred during the course of the study, the analysis showed a high degree of reproducibility for this spatial pattern. With the exception of Mullus surmuletus, the species considered in this investigation exhibit limited variations in their spatial distribution. Finally, in the absence of log-books covering the activities of commercial fishing vessels, these findings constitute a base of reference for the analysis of the dynamics of fishing fleets exploiting the demersal resources of the Gulf of Lions.
Ce travail porte sur une série de campagnes de chalutage de fond réalisé dans le golfe du Lion entre 1983 et 1992. Une nouvelle méthode fondée sur le couplage de la technique multitableaux STATIS et de l'analyse factorielle des correspondances (AFC) est proposée afin d'étudier l'organisation spatio-temporelle des assemblages démersaux, poissons et quelques céphalopodes, en terme de composition spécifique. Cette version AFC de STATIS a fourni une représentation claire de la part stable de l'organisation spatiale des assemblages. De plus, elle nous a permis d'appréhender les variations interannuelles de la distribution de chaque population autour de la structure de référence. Nos résultats montrent que les assemblages démersaux du golfe du Lion présentent une forte structuration spatiale, principalement orientée selon un gradient bathymétrique. Ce dernier est structuré en trois grandes régions: la côte, le plateau continental et le talus continental. En dépit des variations d'échantillonnage survenues au cours de la période d'étude, l'analyse a mis en évidence une forte reproductibilité de ce schéma d'organisation. A l'exception de Mullus surmuletus, les espèces considérées dans ce travail présentent des variations limitées de leur distribution spatiale. Enfin, en l'absence de livres de bord sur l'activité des navires professionnels, ces résultats constituent une base de référence pour l'analyse de la dynamique des flottilles exploitant les ressources démersales dans le golfe du Lion.
Aquatic Living Resources (Elsevier), 1998-03 , Vol. 11 , N. 2 , P. 75-85

Droits : 1998 Published by Elsevier SAS
http://archimer.ifremer.fr/doc/1998/publication-875.pdf
DOI:10.1016/S0990-7440(98)80063-6
http://archimer.ifremer.fr/doc/00000/875/

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
The New Caledonia ophiolite (Peridotite Nappe) is dominated by mantle lithologies, composed of forearc-related refractory harzburgites and minor lherzolites in both the spinel and plagioclase facies.In this study, a comprehensive geochemical data set (major, trace elements and Sr–Nd isotopes) is used to constrain the mantle evolution of the lherzolites and their relationships with the basalts from the Poya Terrane, which tectonically underlies the mantle rocks. The majority of the lherzolites are low-strain porphyroclastic tectonites. They likely record an asthenospheric origin followed by re-equilibration at lithospheric conditions, as supported by geothermometric estimates (T = 1100–940 °C and 920–890 °C for porphyroclastic and neoblastic spinel-facies assemblages, respectively). Olivine composition (Fo = 88.5–90.0 mol%), spinel Cr# ([molar 100 • Cr/(Cr + Al)] = 13–17) and relatively high amounts (7–8 vol%) of Al2O3- and Na2O-rich clinopyroxene (up to 0.5 and 6.5 wt.%, respectively) indicate a moderately depleted geochemical signature for the spinel lherzolites. Bulk rock and clinopyroxene rare earth elements (REE) patterns display a typical abyssal-type signature, i.e. steeply plunging LREE accompanied by nearly flat HREE to MREE. Clinopyroxene REE compositions of the spinel lherzolites may be reproduced by small amounts of fractional melting of a garnet lherzolite precursor (~ 4%), followed by 4%–5% melting in the spinel peridotite field. The plagioclase lherzolites show melt impregnation microstructures, Cr- and Ti-rich spinels and incompatible trace element enrichments (REE, Ti, Y, and Zr) in bulk rocks and clinopyroxenes. Impregnation modelling for these elements suggests that the plagioclase lherzolites originated from residual spinel lherzolites by entrapment of highly depleted (non-aggregated) MORB melt fractions in the shallow oceanic lithosphere. Nd isotope compositions of the investigated peridotites are consistent with derivation from an asthenospheric mantle source that experienced a recent MORB-producing depletion event. This evolution was most likely accomplished in a spreading ridge. However, geochemical trace element modelling and Nd isotopes do not support a genetic mantle–crust link between the lherzolites and enriched-MOR-type basalts from the Poya Terrane.
ISSN: 0024-4937

hal-01412440
https://hal.archives-ouvertes.fr/hal-01412440
DOI : 10.1016/j.lithos.2016.04.030

Éditeur(s) : American Geophysical Union
Résumé : Noise with periods 3 to 10 s, ubiquitous in seismic records, is expected to be mostly generated by pairs of ocean wave trains of opposing propagation directions with half the seismic frequency. Here we present the first comprehensive numerical model of microseismic generation by random ocean waves, including ocean wave reflections. Synthetic and observed seismic spectra are well correlated (r > 0.85). On the basis of the model results, noise generation events can be clustered in three broad classes: wind waves with a broad directional spectrum (class I), sea states with a significant contribution of coastal reflections (class II), and the interaction of two independent wave systems (class III). At seismic stations close to western coasts, noise generated by class II sources generally dominates, but it is intermittently outshined by the intense class III sources, limiting the reliability of seismic data as a proxy for storm climates. The modeled seismic noise critically depends on the damping of seismic waves. At some mid-ocean island stations, low seismic damping is necessary to reproduce the observed high level and smoothness of noise time series that result from a spatial integration of sources over thousands of kilometers. In contrast, some coastal stations are only sensitive to noise within a few hundreds of kilometers. This revelation of noise source patterns worldwide provides a wealth of information for seismic studies, wave climate applications, and new constraints on the possible directional distribution of wave energy.
Journal of Geophysical Research ( JGR ) - Oceans (0148-0227) (American Geophysical Union), 2011-09 , Vol. 116 , N. C09004 , P. 21 p.

Droits : 2011 by the American Geophysical Union
http://archimer.ifremer.fr/doc/00044/15531/12926.pdf
DOI:10.1029/2011JC006952
http://archimer.ifremer.fr/doc/00044/15531/

Éditeur(s) : Elsevier Science Bv
Résumé : Climatic and anthropogenic changes are able to engender modifications in the aerosol composition at different geographical and temporal scales The present study addresses this question for the trace metal concentrations (TM = Al, Fe, Mn, Co, Ni, Cu, Pb, Cd and Zn) of aerosol from the North-western Mediterranean coast of France (Cap Ferrat, nearby Nice) between 1986 and 2008. From seasonal variations (2006-08) and decadal trends (1986-2008) of TM concentrations. three groups of elements can be distinguished They consist of different aerosol sources: crustal-derived elements (Al, Fe. Mn and Co), trace metals of anthropogenic origin (Pb, Cd and Zn) and a third, intermediate, group of trace metals that presented both anthropogenic and natural/crustal influences (Ni and Cu). Reproducible seasonal patterns were observed for crustal and intermediate elements with highest concentrations between May and November. while anthropogenic trace metals did not show a pronounced seasonal cycle Nevertheless, highest concentrations of anthropogenic trace metals occurred mostly in autumn/winter. Aerosol concentrations of anthropogenic TMs decreased remarkably over the last two decades, while crustal trace metals did not show any evolution Nickel and copper aerosol concentrations remained constant, as well. Lead concentrations decreased from 1986 (29.34 ng m(-3)) to 2008 (3.33 ng m(-3)). overall by 90%. Cadmium and zinc aerosol concentrations decreased by 66 and 54%, respectively, between 1998 and 2006-08. from 0.27 to 0.09 ng m(-3) and from 23.9 to 10.9 ng m(-3). respectively. These findings demonstrate the response of the atmospheric environment to the implementation of antipollution policies Possible changes of trace metal emissions sources and local influences are discussed (C) 2010 Elsevier B V. All rights reserved.
Science Of The Total Environment (0048-9697) (Elsevier Science Bv), 2010-06 , Vol. 408 , N. 13 , P. 2629-2638

Droits : 2010 Elsevier B.V. All rights reserved.
http://archimer.ifremer.fr/doc/00006/11688/8503.pdf
DOI:10.1016/j.scitotenv.2010.02.042
http://archimer.ifremer.fr/doc/00006/11688/

Éditeur(s) : HAL CCSD Springer
Résumé : International audience
Traditional network generation models aim to replicate global structural properties observed on various real-world networks through synthetic link formation mechanisms such as triadic closure or preferential attachment. Nowadays, the large amount of data available allow to study more precisely the link formation processes and to compare models with real situations. In this work, we analyze the network formed by the communication activities of the users of a telephony operator for studying the link formation process. Our goal is to identify the underlying formation mechanisms and checking if they match those proposed in traditional models. Indeed, the communications emitted and received by users are strong indicators for understanding the underlying patterns of the link formation process and highlighting how some individual properties induce the formation process in such a network. In a first study conducted at a global level, we show that the traditional mechanisms commonly used in network generation models cannot reproduce alone the link formation in this network. In a second study, we adopt a new point of view and analyze locally the link formation process by searching for correlations between some user attributes and the formation of the new links. The results obtained show that a very strong percentage of new links are formed between individuals with strong similarity.
ISSN: 1869-5450

hal-01312310
https://hal.univ-antilles.fr/hal-01312310
DOI : 10.1007/s13278-015-0304-y

Éditeur(s) : HAL CCSD
Résumé : International audience
Paracetamol and NSAIDs, in particular acetylsalicylic acid (aspirin) and ibuprofen, are among the most used and environmentally released pharmaceutical drugs. The differences in international trends in the sale and consumption of mild analgesics reflect differences in marketing, governmental policies, habits, accessibility, disease patterns and the age distribution of each population. Biomonitoring indicates ubiquitous and high human exposure to paracetamol and to salicylic acid, which is the main metabolite of acetylsalicylic acid. Furthermore, evidence suggests that analgesics can have endocrine disruptive properties capable of altering animal and human reproductive function from fetal life to adulthood in both sexes. Medical and public awareness about these health concerns should be increased, particularly among pregnant women.
Nature Reviews Endocrinology

hal-01359566
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01359566
DOI : 10.1038/nrendo.2016.55
PUBMED : 27150289

Éditeur(s) : Public Library Science
Résumé : Where conservation resources are limited and conservation targets are diverse, robust yet flexible priority-setting frameworks are vital. Priority-setting is especially important for geographically widespread species with distinct populations subject to multiple threats that operate on different spatial and temporal scales. Marine turtles are widely distributed and exhibit intra-specific variations in population sizes and trends, as well as reproduction and morphology. However, current global extinction risk assessment frameworks do not assess conservation status of spatially and biologically distinct marine turtle Regional Management Units (RMUs), and thus do not capture variations in population trends, impacts of threats, or necessary conservation actions across individual populations. To address this issue, we developed a new assessment framework that allowed us to evaluate, compare and organize marine turtle RMUs according to status and threats criteria. Because conservation priorities can vary widely (i.e. from avoiding imminent extinction to maintaining long-term monitoring efforts) we developed a "conservation priorities portfolio" system using categories of paired risk and threats scores for all RMUs (n = 58). We performed these assessments and rankings globally, by species, by ocean basin, and by recognized geopolitical bodies to identify patterns in risk, threats, and data gaps at different scales. This process resulted in characterization of risk and threats to all marine turtle RMUs, including identification of the world's 11 most endangered marine turtle RMUs based on highest risk and threats scores. This system also highlighted important gaps in available information that is crucial for accurate conservation assessments. Overall, this priority-setting framework can provide guidance for research and conservation priorities at multiple relevant scales, and should serve as a model for conservation status assessments and priority-setting for widespread, long-lived taxa.
Plos One (1932-6203) (Public Library Science), 2011-09 , Vol. 6 , N. 9 , P. 1-14

Droits : 2011 Wallace et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License
http://archimer.ifremer.fr/doc/00050/16097/13573.pdf
DOI:10.1371/journal.pone.0024510
http://archimer.ifremer.fr/doc/00050/16097/

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
Since the Shea, J.B. and Morgan (1979) study, investigators have repeatedly shown that the learning of a set of movement patterns (as evaluated in a retention test) is enhanced when acquisition occurred under a random rather than a blocked schedule of practice. Supposedly, this is the case because a random schedule of practice necessitates more elaborate cognitive activities than a blocked schedule before each acquisition trial can be initiated. Our main objective was to determine whether the advantage for learning found for random practice increases as a function of the number of acquisition trials. During acquisition, the results indicated a general tendency for smaller movement reproduction errors under a blocked rather than a random schedule of practice. However, this effect disappeared with larger amount of acquisition trials. In retention, larger errors were observed when acquisition occurred under a blocked rather than a random schedule of practice. Finally, the disadvantage for learning observed for the blocked schedule of practice disappeared under a block-repeated condition in which each movement pattern was first practiced under a blocked schedule which was then repeated a second time. The results are discussed in terms of the so-called contextual interference effect and indicates some of its limitations.
ISSN: 0001-6918

hal-01662846
https://hal.archives-ouvertes.fr/hal-01662846
DOI : 10.1080/00222895.1994.9941657
PUBMED : 8165923