Éditeur(s) : HAL CCSD Maison de la géographie
Résumé : International audience
The paper points out the main divergences between the points of view of the inhabitants of Morne-Rouge (Martinique, French West Indies) and of volcanologists regarding the characteristics of a future eruption of Mount Pelée. The study is based on comparisons between the public’s perception of potentially threatened areas and scientific hazard maps.
El artículo trata de evidenciar las principales discrepancias entre el punto de vista de la población del Morne-Rouge (Martinica) y el de los vulcanólogos en cuanto a las características de una erupción venidera de la montagne Pelée. El estudio se funda, en particular, en una comparación entre la cartografía de la percepción de las zonas amenazadas y la cartografía de las zonas de amenazas volcánicas realizada por los científicos.
L’article met en évidence les principales divergences entre le point de vue des habitants du Morne-Rouge (Martinique) et celui des volcanologues à propos des caractéristiques d’une prochaine éruption de la montagne Pelée. Il s’appuie notamment sur une cartographie de la perception des espaces menacés, confrontée à l’évaluation scientifique des types et des zones d’aléa volcanique.
ISSN: 1769-7298

Droits : info:eu-repo/semantics/OpenAccess
hal-01161639
https://hal.archives-ouvertes.fr/hal-01161639
https://hal.archives-ouvertes.fr/hal-01161639/document
https://hal.archives-ouvertes.fr/hal-01161639/file/PELEE.pdf

Éditeur(s) : Wiley / Blackwell
Résumé : P>New seismic reflection data from the Grand Banks of Newfoundland and the Newfoundland Basin add to the growing knowledge of the composition, structure and history of this non-volcanic margin. Geophysical imaging is now approaching the extent of that done previously on the conjugate margin along Iberia, providing a valuable database for the development of rifting models. Two parallel profiles over the shelf platform image deep crustal fabric representing Precambrian or possibly Appalachian deformation as well as Mesozoic extension. Progressively more intense extension of continental crust is imaged oceanwards without the highly reflective detachments frequently seen on profiles off Galicia. A landward-dipping event 'L' is imaged sporadically and appears to be analogous to a similar event on the Iberian IAM9 profile. The transition zone is probably exposed serpentinized mantle as interpreted off the Iberian margin although there appears to be a difference in the character of ridge development and reflectivity. The distinctive 'U' reflection identified previously at the base of the Newfoundland Basin deep water sedimentary section and recently identified as one or more thin basalt sills is imaged on newly presented profiles that connect previously published profiles SCR3 and SCR2 showing that 'U' is highly regular and continuous except where interrupted by basement highs. 'U' is also seen to have a major impact on the ability to image underlying basement. A full transect beginning over completely unextended continental crust through to oceanic crust has provided a data set from which estimates of extension and the pre-rifting location of the present continental edge can be made. Two estimates were obtained; 85 km based on faulting and 120 km based on crustal thickness.
Geophysical Journal International (0956-540X) (Wiley / Blackwell), 2009-08 , Vol. 178 , N. 2 , P. 1004-1020

Droits : 2009 Wiley / Blackwell
http://archimer.ifremer.fr/doc/2009/publication-6919.pdf
DOI:10.1111/j.1365-246X.2009.04162.x
http://archimer.ifremer.fr/doc/00000/6919/

Éditeur(s) : Université des Antilles Études caribéennes
Résumé : Cet article analyse les interactions socioculturelles d’acteurs multiples ayant des intérêts divergents en regard de la reconnaissance d’un espace naturel à titre d’aire protégée, plus particulièrement le Parc marin du Saguenay–Saint-Laurent (PMSSL), situé au Québec à l’embouchure de la rivière Saguenay. Compris dans le sens d’espace socialisé et investi de valeurs parfois contradictoires, ce territoire constitue le cas empirique sur lequel repose l’analyse des logiques d’acteurs. La perspective ici mise de l’avant repose à la fois sur une décision de l’État de créer et de mettre en valeur une aire marine ainsi que sur la participation active des collectivités territoriales dans la gestion du patrimoine environnemental et culturel lié à leur identité propre. Si la participation des communautés locales apparaît comme un élément essentiel et démocratique dans la reconnaissance d’un espace naturel protégé, il apparaît tout aussi capital de bien saisir la logique qui sous-tend les actions de l’État et du milieu. Les résultats empiriques montrent deux logiques d’action distinctes à l’œuvre, une logique classique de planification et implantation stratégiques de l’état réservant une espace de participation programmée pour la communauté et une logique stratégique communautaire à caractère émergent, de portée moins englobante, mais adaptable aux nouvelles réalités et contraintes gouvernementales. Les résultats peuvent être représentés sous forme d’un processus de gouvernance à l’œuvre, un caractérisé par une participation de base, mais un qui suggère qu’un processus plus hautement démocratique nécessiterait un plus haut degré de vigilance dans la perspective communautaire, suffisante pour produire une meilleure symétrie de pouvoir démocratique entre l’État.
This paper analyzes the socio-cultural dynamic between multiple stakeholders with divergent interests concerning the formalization of the status of a natural area into a protected area. The empirical case under analysis is the creation of the Saguenay Marine Park located at the confluence of the St-lawrence and Saguenay rivers in Québec, a rural region represented by different localities showing some contradictions in socio-economic values and agendas. The dual perspective put forth is, first, the governmental decision one to create and promote a marine protected area, and second, the regional community one to participate in the process and adapt the management of their cultural and environmental heritage to their own perception of their socio-economic identity. The objective of analysis is to identify the logics of action underlying both processes. The empirical results show two distinct logics at work, a government logic of classic managerial planning and implementation into which the community has a programmed role and a community logic of emergent planning, less comprehensive in scope, but adaptable to the emerging realities and limitations of the governmnent one. They can be seen in tandem as representing a governance process at work, one with a basic participative character, but one which suggests that an enhanced democratic process entails a higher vigilance level from a community perspective, such as to produce a more even democratic symmetry of powers between the State and the regional community.
Québec

Droits : info:eu-repo/semantics/openAccess
urn:doi:10.4000/etudescaribeennes.3565
http://journals.openedition.org/etudescaribeennes/3565

Éditeur(s) : Wiley-blackwell
Résumé : The reef fauna connectivity of the West Indian Ocean (WIO) is one of the least studied globally. Here we use genetic analyses of the grouper Epinephelus merra (Bloch 1793) to determine patterns of connectivity and to identify barriers to dispersal in this WIO marine area. Phylogeographic and population-level analyses were conducted on cytochrome b sequences and microsatellites (13 loci) from 557 individuals sampled in 15 localities distributed across the West Indian Ocean. Additional samples from the Pacific Ocean were used to benchmark the WIO population structure. The high level of divergence revealed between Indian and Pacific localities (of about 4.5% in sequences) might be the signature of the major tectonic and climatic changes operating at the Plio-Pleistocene transition, congruently with numerous examples of Indo-Pacific speciation. In comparison, the E. merra sequences from the Indian Ocean constitute a monophyletic clade with a low average genetic distance (d < 0.5%). However both genetic markers indicated some structure within this ocean. The main structure revealed was the isolation of the Maldives from the WIO localities (a different group signature identified by clustering analysis, great values of differentiation). Both marker types reveal further significant structure within the WIO, mainly the isolation of the Mascarene Islands (significant AMOVA and isolation-by-distance patterns) and some patchy structure between the northernmost localities and within the Mozambique Channel. The WIO genetic structure of E. merra appeared congruent with main biogeographic boundaries and oceanographic currents.
Marine Ecology-an Evolutionary Perspective (0173-9565) (Wiley-blackwell), 2015-09 , Vol. 36 , N. 3 , P. 447-461

Droits : 2014 Blackwell Verlag GmbH
http://archimer.ifremer.fr/doc/00189/30046/28566.pdf
DOI:10.1111/maec.12153
http://archimer.ifremer.fr/doc/00189/30046/

Éditeur(s) : Wiley-blackwell Publishing, Inc
Résumé : P>Torsvik et al. recently presented a revised model for the opening of the South Atlantic Ocean. According to these authors, this new plate tectonic model is internally consistent and consistent with globally balanced plate motion solutions and takes into account realistic intraplate deformation. However, this model shows a number of kinematic and geological problems that we underline here, together with some comparisons with the new kinematic model recently proposed by Moulin et al.
Geophysical Journal International (0956-540X) (Wiley-blackwell Publishing, Inc), 2010-10 , Vol. 183 , N. 1 , P. 20-28

Droits : info:eu-repo/semantics/openAccess
http://archimer.ifremer.fr/doc/00014/12504/9878.pdf
DOI:10.1111/j.1365-246X.2010.04727.x
http://archimer.ifremer.fr/doc/00014/12504/

Éditeur(s) : Université des Antilles
Résumé : Una introducción a la seguridad turística requiere que nos ocupemos de una revisión bibliográfica. Ciertamente, los planes y los manuales parecen no traducirse en protocolos en momentos de emergencia. Ello sucede pues siempre un estado de emergencia se escapa de toda planificación pero también suele suceder por la falta de definiciones claras respecto a que es la seguridad. En este ensayo, discutiremos los paradigmas y tesis centrales de tres exponentes que han dedicado su vida a dicha tarea. Sevil Somnez, Abraham Pizam y Peter Tarlow han explorado las raíces del terrorismo y la seguridad por más de 20 años, y por eso, a pesar de la crítica, merecen su reconocimiento. La mejor forma de homenajearlos es discutir críticamente sus postulados. Con sus puntos de divergencia, los especialistas se encuentran preocupados por la dependencia occidental del terrorismo con los medios masivos de comunicación, aspecto a discutir en el presente trabajo de revisión.
Une introduction à la sécurité touristique nécessite un examen bibliographique. Certainement, les plans et les manuels semblent ne pas être traduits dans des protocoles de moments de secours. Il s’agit donc toujours d’état d'urgence confronté à l’évènement, sans planification et sans définitions claires de ce qu’est la sécurité. Dans cet essai, nous discuterons les paradigmes et les thèses centrales de trois auteurs qui ont consacré leur vie à la tâche mentionnée ci-dessus. Sevil Somnez, Abraham Pizam et Peter Tarlow ont exploré les racines du terrorisme et la sécurité pendant plus de 20 ans et pour cela, en dépit de la critique, ils méritent notre reconnaissance. La meilleure façon de leur rendre hommage est de discuter de manière critique de leurs postulats. Au-delà de leurs divergences, les spécialistes s’inquiètent de la dépendance occidentale au terrorisme sous le poids des mass-médias, aspect qu’il convient de discuter dans le présent travail de révision.
The specialized literature review is of paramount importance at time of exploring the current problems of tourism security. Certainly, plans and policies provided by guide-books are not being followed in disaster-contests simply chaos and disorder are the nature of emergencies. Beyond any protocol, crises and security are not properly defined by scholars. In this essay-review, we will not pay attention to define what tourism security means, lest by the lens of three senior scholars, Sevil Somnez, Abraham Pizam and Peter Tarlow, who have accomplished this task. They have explored not only the roots of terrorism but security over 20 years. Despite the criticism, they deserve recognition for this legacy. Based on substantial point of divergence, these specialists are concerned by the financial dependency of societies respecting to mass-media and its coverage of terrorist attacks.

Droits : info:eu-repo/semantics/openAccess
urn:doi:10.4000/etudescaribeennes.7530
http://etudescaribeennes.revues.org/7530

Éditeur(s) : Université de la Réunion
Résumé : The green turtle (Chelonia mydas) is an emblematic species of marine life. However, nowadays it is subject to many threats (poaching, by-catch). Even if there is deep growing measures for its protection, the green turtle still is an endangered species and it is listed in Appendix I of Washington Convention (CITES). In order to elaborate efficient conservation and management plans, perfect knowledge of green turtle biology, but also of its population structure and their characteristics, are needed. In this thesis, we have assessed genetic structure of green turtle populations in the South-Western Indian Ocean by using genetic tools. In all, 1551 tissue samples have been collected from our study zone and from our control site French Polynesia (37 samples). All kinds if individuals were sampled (except males in reproductive phase) from 15 sampling sites including nesting, foraging, and immature development site. We used both control region of mitochondrial DNA and 6 microsatellite loci to better infer maternal and paternal lineages. We identified 29 haplotypes in the South-Western Indian Ocean. They are distributed in 3 independent and highly divergent clades, including one composed with haplotypes from Atlantic Ocean. For 7 of these haplotypes, it was the first time they were detected in the study zone. Fifteen haplotypes were previously undescribed, distributed in all the 3 clades. These new haplotypes seem to be specific to the South-Western Indian Ocean, which is then an original zone. Besides, we found a high allelic richness. These results show the South-western Indian Ocean is rich and very diversified. This region plays an important role in the global diversity of the species. The South-Western Indian Ocean is one of the two contact zones presently known between the two metapopulations of green turtles (Atlantic-Mediterranean and Indo-Pacific). This contact induces a genetic cline based on CM8 (Atlantic) and C3 (Indo-Pacific) haplotype frequencies. Analysis of the microsatellite differentiation between individuals provides evidence of genetic exchanges between the two metapopulations in the region. The South-Western Indian Ocean participates to green turtle global genetic mixing. Studying the influence of several intrinsic and extrinsic factors on population structuring provides useful information for management plan elaboration. We found no significant difference between genetic structures of foraging females and males, contrary to immature turtles which seem to be organised in 'regional pools'. This organisation could be due to both immature natal homing and influence of oceanic currents. High mitochondrial differentiation of nesting females and low global microsatellite differentiation of our samples indicate male-mediated gene flow among populations of the study zone. The genetic composition of a sampling site presents no significant variation along the year, even if we could notice some trends. Nevertheless, it can be significantly different from a year to an other one. This may result from alternation of distinct populations on the same site. We noticed different evolution in 10 or 20 years of the genetic composition depending on the sampling site. Geographic distance seems not to have significant influence on population structuring concerning microsatellite markers. Nesting females of Saziley Beach (Mayotte Island, Comoros Archipelago) present genetic divergence from females nesting in the two other sampled beaches of this island. The observed population structure shows no contradiction with the organisation of oceanic currents in the South-Western Indian Ocean. Comparing the results from the two genetic markers used, we identified 8 genetic differentiated clusters of turtles in the study zone and at least 6 distinct populations. These clusters constitute 8 potential management units (MUs) which could serve as basis in the elaboration of conservation and management plans.
La tortue verte (Chelonia mydas) constitue l'un des espèces emblématiques de la vie marine, pourtant de nombreuses menaces pèsent de nos jours encore sur sa survie (braconnage, captures accidentelles). Ainsi, malgré l'essor de mesures de protection menées à travers pour sa sauvegarde, la tortue verte constitue une espèce 'en danger d'extinction' et figure dans l'Annexe I de la Convention de Washington (CITES). Afin d'élaborer des plans de gestion et de conservation qui soient efficaces, il est important d'avoir une parfaite connaissance de la biologie de la tortue verte, mais aussi de la structure de ses populations et de leurs caractéristiques. C'est dans ce cadre que s'inscrit la présente étude. L'objectif de cette étude était d'acquérir des connaissances sur la structure des populations de tortues vertes dans le sud-ouest de l'océan Indien grâce à l'utilisation de l'outil génétique. Au total, 1551 échantillons de tissu ont été collectés dans la zone d'étude et dans notre site témoin la Polynésie française (37 échantillons). Toutes les catégories d'individus ont été échantillonnées (excepté les mâles en phase de reproduction) et les 15 sites d'échantillonnage comprennent à la fois des sites de ponte, d'alimentation et de développement pour les immatures. Deux types de marqueurs ont été utilisés : la région contrôle de l'ADN mitochondrial et 6 loci microsatellites, afin d'appréhender au mieux l'apport des lignées maternelles et paternelles. Nous avons pu mettre en évidence la présence dans le sud-ouest de l'océan Indien de 29 haplotypes distincts, appartenant à trois clades fortement divergents dont l'un constitué d'haplotypes originaires de l'océan Atlantique. Parmi ces haplotypes, 7 ont été détectés pour la première fois dans la zone d'étude, et 15 autres n'ont jamais été précédemment décrits chez cette espèce. Ils sont présents dans chacun des 3 clades d'haplotypes. Ces nouveaux haplotypes semblent spécifiques à la région, et en font une zone originale. On observe par ailleurs une grande richesse allélique dans les effectifs analysés. Ces résultats montrent que le sud-ouest de l'océan Indien est une zone riche et très diversifiée. Cette région joue un rôle important dans la diversité génétique globale de l'espèce. Le sud-ouest de l'océan Indien constitue l'une des deux seules zones connues à l'heure actuelle de contact entre les deux métapopulations de tortues vertes (Atlantique-Méditerranée et Indo-Pacifique). Ce contact a entraîné la formation d'un cline génétique portant principalement sur les fréquences relatives des haplotypes CM8 (Atlantique) et C3 (Indo-Pacifique). Les résultats obtenus lors de l'analyse microsatellite de la différenciation entre les individus originaires des deux métapopulations montrent que le sud-ouest de l'océan Indien constitue une zone d'échanges génétiques entre les deux métapopulations, participant au brasage génétique de l'espèce. L'étude de facteurs, intrinsèques et extrinsèques, pouvant influencer la structuration des populations apportent de nombreuses informations qui pourraient s'avérer utiles lors de l'élaboration de plans de gestion. La structure des femelles et des mâles en alimentation ne diffère pas, contrairement à celle des immatures qui semble s'organiser en 'pools régionaux' qui seraient le fruit de l'interaction d'un comportement de philopatrie et d'une influence des courants océaniques. La forte différenciation mitochondriale des femelles en ponte et la très faible différenciation microsatellite observée à l'échelle de la région, indiquent l'existence de flux de gènes via les mâles. La composition génétique d'un site ne varie pas de manière significative au cours de l'année. Par contre, elle peut varier d'une année à l'autre, signifiant l'alternance dans certains sites de ponte de plusieurs populations distinctes. L'évolution de la composition génétique d'un groupe, au cours de 10 ou 20 ans, diffère selon le site considéré. La distance ne semble pas influencer de manière significative la structuration des populations au niveau microsatellite. Les femelles en ponte sur la plage de Saziley (Mayotte) diffèrent génétiquement de celles pondant sur les deux autres plages de l'île. La structure observée des populations est en accord avec l'organisation des courants océanique dans la région. La confrontation des résultats obtenus à partir des deux marqueurs génétiques utilisés, permet la détermination de 8 ensembles génétiquement différenciés dans la zone d'étude et l'identification d'au moins 6 populations distinctes. Ces ensembles constituent autant d'unités de gestion (MUs) potentielles qui pourront servir de base à l'élaboration de plans de gestion et de conservation.

Droits : info:eu-repo/semantics/openAccess
http://archimer.ifremer.fr/doc/2007/these-3532.pdf
http://archimer.ifremer.fr/doc/00000/3532/

Éditeur(s) : HAL CCSD Oxford University Press (OUP)
Résumé : International audience
Rifting in a cratonic lithosphere is strongly controlled by several interacting processes including crust/mantle rheology, magmatism, inherited structure and stress regime. In order to better understand how these physical parameters interact, a 2 yr long seismological experiment has been carried out in the North Tanzanian Divergence (NTD), at the southern tip of the eastern magmatic branch of the East African rift, where the southward-propagating continental rift is at its earliest stage. We analyse teleseismic data from 38 broad-band stations ca. 25 km spaced and present here results from their receiver function (RF) analysis. The crustal thickness and Vp/Vs ratio are retrieved over a ca. 200 × 200 km2 area encompassing the South Kenya magmatic rift, the NTD and the Ngorongoro-Kilimanjaro transverse volcanic chain. Cratonic nature of the lithosphere is clearly evinced through thick (up to ca. 40 km) homogeneous crust beneath the rift shoulders. Where rifting is present, Moho rises up to 27 km depth and the crust is strongly layered with clear velocity contrasts in the RF signal. The Vp/Vs ratio reaches its highest values (ca. 1.9) beneath volcanic edifices location and thinner crust, advocating for melting within the crust. We also clearly identify two major low-velocity zones (LVZs) within the NTD, one in the lower crust and the second in the upper part of the mantle. The first one starts at 15–18 km depth and correlates well with recent tomographic models. This LVZ does not always coexist with high Vp/Vs ratio, pleading for a supplementary source of velocity decrease, such as temperature or composition. At a greater depth of ca. 60 km, a mid-lithospheric discontinuity roughly mimics the step-like and symmetrically outward-dipping geometry of the Moho but with a more slanting direction (NE–SW) compared to the NS rift. By comparison with synthetic RF, we estimate the associated velocity reduction to be 8–9 per cent. We relate this interface to melt ponding, possibly favouring here deformation process such as grain-boundary sliding (EAGBS) due to lithospheric strain. Its geometry might have been controlled by inherited lithospheric fabrics and heterogeneous upper mantle structure. We evidence that crustal and mantle magmatic processes represent first order mechanisms to ease and locate the deformation during the first stage of a cratonic lithospheric breakup.
ISSN: 0956-540X

hal-01622078
https://hal.archives-ouvertes.fr/hal-01622078
https://hal.archives-ouvertes.fr/hal-01622078/document
https://hal.archives-ouvertes.fr/hal-01622078/file/plasmanGJI2017.pdf
DOI : 10.1093/gji/ggx177

Résumé : Le maintien de ressources génétiques suffisamment larges est nécessaire pour assurer la viabilité et le potentiel évolutif des populations naturelles. Cette thèse a le principal objectif de caractériser la diversité et la variabilité génétique chez le genre Virola (Myristicaceae) pour décrire les processus évolutifs qui en sont à l'origine. Premièrement,une étude de la régénération d'un échantillonnage exhaustif de V. michelii a été menée dans une parcelle du dispositif expérimental de Paracou ayant subi une exploitation forestière de faible intensité et comparée à une parcelle témoin. La diversité génétique mesurée à partir de marqueurs AFLP (Amplified Fragment-Length Polymorphism, N=229) en zones perturbées s'est révélée être plis grande qu'en zone non-perturbées. Puis, l'adaptation locale a été étudiée à travers ces mêmes individus et certains loci (AFLP) montrent une sélection divergente pour des environnements contrastés, indiquant un signe d'adaptation. Enfin, l'étude des niveaux de divergence génétique chez trois espèces de Virola du bouclier guyanais (V. michelii, V. surinamensis et V. kwatae) montrent que deux d'entre elles (V. surinamensis et V. kwatae) montrent de fortes similarités génétiques malgré leur distribution sur des environnements contrastés. des Flux de gènes intersécifiques ont été mis en évidence chez ces deux espèces-soeurs et l'hypothèse d'une spéciation écologique est avancée. Ce travail a permis d'aborder différents processus évolutifs à l'origine de la diversité génétique actuelle chez ces espèces forestières tropicales et peut fournir une contribution pour appréhender le devenir des populations.
Genetic diversity is an essential component of biodiversity. The maintenance of sufficient genetic resources is needed to ensure the adaptive potential and the viability of natural populations. In the current context of global changes, the study of adaptation in living organisms is a key task, particularly for tropical forest trees that are dominant components (in terms of biomass and as ecological drivers) of some of the most diverse ecosystems on Earth. The main objective of this thesis is to characterize genetic diversity and genetic variability to understand the evolutionary processes that act on them. This ecological-genetic study was carried out at the interspecific and intraspecific level in the Virola genus.If overall high levels of genetic diversity are a guarantee of prosperity for the future of the species, it seems essential to perform studies on the impact of environmental disturbance on genetic diversity. In the first section, the genetic consequences of regeneration dynamics were studied in an exhaustive sample of V. michelii in a low-intensity logging plot and in a control plot at the Paracou experimental site. A greater genetic diversity, measured from AFLP markers (Amplified Fragment Length Polymorphism, N = 229), was found in perturbed areas. Because studying genetic diversity within species may be useful for understanding species adaptation to environmental changes, in the second section. I studied local adaptation in a population of V. michelii on the Paracou experimental site. A genome scan approach with AFLPs (N = 229) was conducted on 77 adult individuals and 401 juveniles to identify genetic differences between populations associated to contrasting conditions for an array of environmental variables. Some loci (N = 2) were found to be subject to divergent selection, indicating adaptation to contrasting habitats.In the third section, the study of levels of genetic divergence in three Virola species of the Guiana Shield (V. michelii, V. surinamensis and V. kwatae) was investigated for nuclear and chloroplast molecular markers. V. surinamensis and V. kwatae showed strong genetic similarities despite their contrasting habitats preferences. Coalescent analyses have revealed, on one hand, a recent divergence between these two species suggesting an ecological speciation, and one the other hand that interspecific gene flow occurs between these sister-species.This work focuses on understanding evolutionary processes shaping genetic diversity and provides a useful contribution for biodiversity conservation programs.

http://www.theses.fr/2011AGUY0480/document

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
Tethyan ophiolites show an apparent poorly organized association of ultramafic andmafic rocks. By contrast tothe complete mantle-crustal sections of Semail-type ophiolite sheets, Tethyan ophiolites are characterized by asmaller amount of mafic rocks (gabbros and basalts), by the absence of any sheeted dyke complex and by thefrequent occurrence of oceanic sediments stratigraphically overlying mantle-derived peridotites and associatedgabbroic intrusions. Therefore, they are considered as typical remnants of oceanic lithosphere formed in slowspreadingenvironment or in ocean–continent transition at distal passive margins. In the very first models offormation of the Tethyan ophiolites, in the years 1980, the geodynamical processes leading to mantle unroofingwere poorly understood due to the paucity of data and concepts available at that time from the present-dayoceans. In particular, at that time, little work had focused on the distribution, origin and significance ofmafic rocks with respect to the dominant surrounding ultramafics. Here, we reconsider the geology of sometypical metaophiolites from the Western Alps and Corsica, and we show how results from the past decadeobtained in the current oceans ask for reassessing the significance of the Tethyan ophiolites in general. Revisitedexamples include a set of representative metaophiolites from the blueschists units of the Western Alps (Queyrasregion) and from Alpine Corsica (Golo Valley). Field relationships between the ophiolitic basement andthe metasedimentary/metavolcanic oceanic cover are described, outlining a typical character of the Tethyanophiolite lithological associations. Jurassic marbles and polymictic ophiolite metabreccias are unconformablyoverlying the mantle-gabbo basement, in a way strictly similar to what is observed in the non-metamorphicAppennine ophiolites or Chenaillet massif. This confirms that very early tectonic juxtaposition of ultramafic andmafic rocks occurred in the oceanic domain before subduction. This juxtaposition resulted from tectonic activitythat is now assigned to the development of detachment faults and to the formation of Oceanic Core Complexes(OCCs) at the axis of slow spreading ridges. This fundamental Plate Tectonics process is responsible for the exhumationand for the axial denudation of mantle rocks and gabbros at diverging plate boundaries. In addition, fieldrelationships between the discontinuous basaltic formations and the ultramafic–mafic basement indicate that thistectonic stage is followed or not by a volcanic stage.We discuss this issue in the light of available field constraints.
ISSN: 0012-8252

insu-01096467
https://hal-insu.archives-ouvertes.fr/insu-01096467
https://hal-insu.archives-ouvertes.fr/insu-01096467/document
https://hal-insu.archives-ouvertes.fr/insu-01096467/file/Lagabrielle-EarthSciRev-2014.pdf
DOI : 10.1016/j.earscirev.2014.11.004

Éditeur(s) : HAL CCSD
Résumé : International audience
High Pressure - Low Temperature (HP-LT) rocks testify for burying and exhumation of crustal material in subduction zones. The question of their exhumation is nevertheless still unclear. The Aegean domain offers several HP-LT belts. Especially, the Attic-Cycladic Blueschist unit (ACBU) is an example of a HP-LT unit exhumed in a convergent and then in a divergent context. It actually appears in metamorphic core complexes (MCCs) formed in the back-arc of the subduction. The syn-convergence "message" is however difficult to read because of the post-convergence structural and thermal overprint that accompanied the formation of the MCCs. Particularly, the geometry, the timing and the amount of the syn-orogenic exhumation remain unclear. We investigate theses questions with metamorphic petrology (Andros and Ios islands) and phengite population, single grain and in situ 40Ar-39Ar geochronology (Andros, Tinos, Syros and Ios islands). Based on these new constraints and a synthesis of published data, we are able to refine the geometry, the timing and the modes of the exhumation of the ACBU. Data from the whole Cyclades exhibit little differences in the age and P-T conditions at the successive stages of syn-orogenic exhumation. The peak of pressure (500±50 °C-18±1 kbar) has been reached at 50-55 Ma. The onset of the exhumation occurred at 40-45 Ma in blueschist facies conditions, between a basal thrust and a summital detachment. The following decompression was accompanied by cooling until 30-35 Ma (400±50 °C-8±1 kbar). At that time, the boundary conditions switched to extension. The change in boundary conditions is recorded by slowing of the exhumation and isobare heating. The conditions of post-orogenic exhumation differ from an island to another. The onset of post-orogenic exhumation is dated around 30 Ma in the northern Cyclades and 25 Ma in the southern Cyclades. It is related to top-to-the-North deformation in all the studied domain. The end of ductile deformation below the detachments is also diachronous (21 Ma in the North and 18 Ma in the South). Finally, we propose a model for the final steps of the exhumation related to the intrusion of granitic bodies around 14 Ma.
American Geophysical Union, Fall Meeting
San Francisco, United States

insu-00860510
https://hal-insu.archives-ouvertes.fr/insu-00860510
BIBCODE : 2010AGUFM.T23C2301L

Éditeur(s) : HAL CCSD Public Library of Science
Résumé : International audience
Few studies have been undertaken to assess the possible effects of bisphenol A (BPA) on the reproductive hormone balance in animals or humans with often contradictory results. We investigated possible direct endocrine disruption by BPA of the fetal testes of 2 rat strains (14.5-17.5 days post-coitum) and humans (8-12 gestational weeks) and under different culture conditions. BPA concentrations of 10-8M and 10-5M for 72h reduced testosterone production by the Sprague-Dawley fetal rat testes, while only 10-5M suppressed it in the Wistar strain. The suppressive effects at 10-5M were seen as early as 24h and 48h in both strains. BPA at 10-7-10-5M for 72h suppressed the levels of fetal rat Leydig cell insulin-like factor 3 (INSL3). BPA exposure at 10-8M, 10-7M, and 10-5M for 72h inhibited testosterone production in fetal human testes. For the lowest doses, the effects observed occurred only when no gonadotrophin was added to the culture media and were associated with a poorly preserved testicular morphology. We concluded that (i) BPA can display anti-androgenic effects both in rat and human fetal testes; (ii) it is essential to ascertain that the divergent effects of endocrine disruptors between species in vitro do not result from the culture conditions used, and/or the rodent strain selected; (iii) the optimization of each in vitro assay for a given species should be a major objective rather than the search of an hypothetical trans-species consensual model-system, as the organization of the testis is intrinsically different between mammalian species; (iv) due to the uncertainty existing on the internal exposure of the human fetal testis to BPA, and the insufficient number of epidemiological studies on the endocrine disruptive effects of BPA, caution should be taken in the extrapolation of our present results to the human reproductive health after fetal exposure to BPA.
ISSN: 1932-6203

hal-01121759
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01121759
PUBMED : 25706302
DOI : 10.1371/journal.pone.0117226

Éditeur(s) : HAL CCSD Wiley-Blackwell
Résumé : International audience
Based on their small size and genomic properties, ultrasmall prokaryotic groups like the Candidate Phyla Radiation have been proposed as possible symbionts dependent on other bacteria or archaea. In this study, we use a bipartite graph analysis to examine patterns of sequence similarity between draft and complete genomes from ultrasmall bacteria and other complete prokaryotic genomes, assessing whether the former group might engage in significant gene transfer (or even endosymbioses) with other community members. Our results provide preliminary evidence for many lateral gene transfers with other prokaryotes, including members of the archaea, and report the presence of divergent, membrane-associated proteins among these ultrasmall taxa. In particular, these divergent genes were found in TM6 relatives of the intracellular parasite Babela massiliensis.
ISSN: 1462-2912

Droits : http://creativecommons.org/licenses/by/
hal-01480348
http://hal.upmc.fr/hal-01480348
http://hal.upmc.fr/hal-01480348/document
http://hal.upmc.fr/hal-01480348/file/emi13477.pdf
DOI : 10.1111/1462-2920.13477

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) : HAL CCSD Wiley
Résumé : [b]Aim[/b][br/] Many tropical tree species have poorly delimited taxonomic boundaries and contain undescribed or cryptic species. We examined the genetic structure of a species complex in the tree genus Carapa in the Neotropics in order to evaluate age, geographic patterns of diversity and evolutionary relationships, and to quantify levels of introgression among currently recognized species.[br/] [br/] [b]Location[/b][br/] Lowland moist forests in the Guiana Shield, the Central and Western Amazon Basin, Chocó and Central America.[br/] [br/] [b]Methods[/b][br/] Genetic structure was analysed using seven nuclear simple sequence repeats (nuSSR), five chloroplast SSRs (cpSSR), and two chloroplast DNA (cpDNA) intergenic sequences (trnH-psbA and trnC-ycf6). Bayesian clustering analysis of the SSR data was used to infer population genetic structure and to assign 324 samples to their most likely genetic cluster. Bayesian coalescence analyses were performed on the two cpDNA markers to estimate evolutionary relationships and divergence times.[br/] [br/] [b]Results[/b][br/] Two genetic clusters (nu_guianensis and nu_surinamensis) were detected, which correspond to the Neotropical species C. guianensis (sensu latu) and C. surinamensis. Fourteen cpDNA haplotypes clustered into six haplogroups distributed between the two nuclear genetic clusters. Divergence between the haplogroups was initiated in the Miocene, with some haplotype structure evolving as recently as the Pleistocene. The absence of complete lineage sorting between the nuclear and chloroplast genomes and the presence of hybrid individuals suggest that interspecific reproductive barriers are incomplete. NuSSR diversity was highest in C. guianensis and, within C. guianensis, cpDNA diversity was highest in the Central and Western Amazon Basin. Regional genetic differentiation was strong but did not conform to an isolation-by-distance process or exhibit a phylogeographical signal.[br/] [br/] [b]Main conclusions[/b][br/] The biogeographical history of Neotropical Carapa appears to have been influenced by events that took place during the Neogene. Our results point to an Amazonian centre of origin and diversification of Neotropical Carapa, with subsequent migration to the Pacific coast of South America and Central America. Gene flow apparently occurs among species, and introgression events are supported by inconsistencies between chloroplast and nuclear lineage sorting. The absence of phylogeographical structure may be a result of the ineffectiveness of geographical barriers among populations and of reproductive isolation mechanisms among incipient and cryptic species in this species complex.
ISSN: 0305-0270

hal-01032395
https://hal.archives-ouvertes.fr/hal-01032395
DOI : 10.1111/j.1365-2699.2011.02678.x

Résumé : Le genre Crassostrea regroupe de nombreuses espèces dont la répartition mondiale s'étend sur une grande partie des régions côtières des basses et moyennes latitudes. La classification des différentes espèces décrites à partir des critères morphologiques et de répartition géographique est aujourd'hui remise en cause dans de nombreux cas par les nouvelles études utilisent les techniques récentes de biologie moléculaire. C'est en particulier grâce à l'apport des séquences génomiques variables, qu'il a été possible de déterminer différentes espèces présentes sur les côtes africaines et américaines (Lapègue & al.). La présence de l'espèce C. gasar, d'abord décrite en Afrique, a ainsi été montré en Amérique. La répartition de cette espèce sur les deux continents laisse supposer que les barrières géographiques on induit une limitation des flux géniques et donc permis une divergence génétique des populations. Pour confirmer cette hypothèse une étude génétique des populations sur 3 populations de chaque continent a donc été réalisée. Elle s'est basée sur le marqueur nucléaire ITS2, séquence non transcrite et variable du génome nucléaire. Il a donc été possible, grâce aux techniques de RFLP (restriction fragments length polymorphisme) de démontrer une forte différenciation génétique entre les deux continents. Cependant le séquençage montre une divergence nucléotidique faible (3%). Ceci laisse supposer qu'il n'y a pas de flux génique entre les deux continents, et que les populations ont divergé récemment. De plus, le polymorphisme intracontinental observé uniquement en Afrique nous laisse supposer les populations américaines seraient originaires d'Afrique. La mise au point du séquençage et la lecture de deux séquences pour des individus de chaque continent a de plus permis de sélectionner de nouvelles enzymes de restriction utilisable en RFLP pour poursuivre l'étude du polymorphisme entre les populations.

Droits : 2001 Univ. La Rochelle, Ifremer
http://archimer.ifremer.fr/doc/00033/14407/11700.pdf
http://archimer.ifremer.fr/doc/00033/14407/

Éditeur(s) : Université des Antilles Études caribéennes
Résumé : Una introducción a la seguridad turística requiere que nos ocupemos de una revisión bibliográfica. Ciertamente, los planes y los manuales parecen no traducirse en protocolos en momentos de emergencia. Ello sucede pues siempre un estado de emergencia se escapa de toda planificación pero también suele suceder por la falta de definiciones claras respecto a que es la seguridad. En este ensayo, discutiremos los paradigmas y tesis centrales de tres exponentes que han dedicado su vida a dicha tarea. Sevil Somnez, Abraham Pizam y Peter Tarlow han explorado las raíces del terrorismo y la seguridad por más de 20 años, y por eso, a pesar de la crítica, merecen su reconocimiento. La mejor forma de homenajearlos es discutir críticamente sus postulados. Con sus puntos de divergencia, los especialistas se encuentran preocupados por la dependencia occidental del terrorismo con los medios masivos de comunicación, aspecto a discutir en el presente trabajo de revisión.
Une introduction à la sécurité touristique nécessite un examen bibliographique. Certainement, les plans et les manuels semblent ne pas être traduits dans des protocoles de moments de secours. Il s’agit donc toujours d’état d'urgence confronté à l’évènement, sans planification et sans définitions claires de ce qu’est la sécurité. Dans cet essai, nous discuterons les paradigmes et les thèses centrales de trois auteurs qui ont consacré leur vie à la tâche mentionnée ci-dessus. Sevil Somnez, Abraham Pizam et Peter Tarlow ont exploré les racines du terrorisme et la sécurité pendant plus de 20 ans et pour cela, en dépit de la critique, ils méritent notre reconnaissance. La meilleure façon de leur rendre hommage est de discuter de manière critique de leurs postulats. Au-delà de leurs divergences, les spécialistes s’inquiètent de la dépendance occidentale au terrorisme sous le poids des mass-médias, aspect qu’il convient de discuter dans le présent travail de révision.
The specialized literature review is of paramount importance at time of exploring the current problems of tourism security. Certainly, plans and policies provided by guide-books are not being followed in disaster-contests simply chaos and disorder are the nature of emergencies. Beyond any protocol, crises and security are not properly defined by scholars. In this essay-review, we will not pay attention to define what tourism security means, lest by the lens of three senior scholars, Sevil Somnez, Abraham Pizam and Peter Tarlow, who have accomplished this task. They have explored not only the roots of terrorism but security over 20 years. Despite the criticism, they deserve recognition for this legacy. Based on substantial point of divergence, these specialists are concerned by the financial dependency of societies respecting to mass-media and its coverage of terrorist attacks.

Droits : info:eu-repo/semantics/openAccess
urn:doi:10.4000/etudescaribeennes.7543
http://journals.openedition.org/etudescaribeennes/7543

Éditeur(s) : Elsevier Sci Ltd
Résumé : Several marine geophysical data and piston-coring surveys acquired during the last decade allow one to better understand the close dynamic interactions between the sand-rich Orinoco turbidite system and the compressional structures of the Barbados prism. These interactions have been active since Eocene time as illustrated by the study of outcrops onshore Barbados Island. Because of strong morphologic and tectonic control in the east-Caribbean active margin, the present-day Orinoco turbiditic pattern system does not exhibit a classic fan geometry. The sea-floor geometry between the slope of the front of the Barbados prism and the slope of the South-American margin induces the convergence of the turbidite channels toward the abyssal plain, at the front of the accretionary prism. Also, whereas in most passive margins the turbidite systems are organized upstream to downstream as canyon, channel-levee and lobes, here, due to the tectonic control, the sedimentary system is organized upstream to downstream as channel-levee, canyons and channelized lobes. Indeed, at the edge of the Orinoco platform, the system has multiple sources with several distributaries and downstream the channel courses are complex with frequent convergences or divergences that are emphasized by the effects of the undulating seafloor tectonic morphologies associated with active thrust tectonics and mud volcanism. On top of the accretionary prism, turbidite sediments are filling transported piggy-back basins whose timing of sedimentation vs. deformation is complex. While erosion processes are almost absent on the highly subsiding Orinoco platform and in the upper part of the turbidite system, they develop mostly between 2000 and 4000 m of water depth, above the compressional structures of the Barbados prism (canyons up to 3 km wide and 300 m deep). In the abyssal plain, the main turbiditic channel develops toward the east and connects with the Vidal mid-Atlantic channel. The sediments transported in this channel are filling several elongated basins linked with fracture zones (notably the Barracuda Basin), and finally end their course in the Puerto-Rico trench, the deepest morphologic depression of the region. Piston-cores have demonstrated that turbidite sediments above the accretionary prism and in the abyssal plain are mostly coarse sandy deposits covered by recent pelagic planktonic-rich sediments, which corresponds to slower sand deposition during the post-glacial sea level rise. Numerical stratigraphic modelling suggests that during the last glacial event, the main depocentres were located above the tectonic prism and in the abyssal plain, at the front of the prism and that, during the Holocene eustatic rise, a large accommodation space formed on the shelf confining sedimentation mostly on the Orinoco deltaic platform and producing a starvation downstream in the turbidite system.
Marine And Petroleum Geology (0264-8172) (Elsevier Sci Ltd), 2015-06 , Vol. 64 , P. 76-103

Droits : 2015 Elsevier Ltd. All rights reserved.
http://archimer.ifremer.fr/doc/00252/36373/34913.pdf
DOI:10.1016/j.marpetgeo.2014.12.015
http://archimer.ifremer.fr/doc/00252/36373/

Éditeur(s) : HAL CCSD Royal Society, The
Résumé : Plant leaf litter generally decomposes faster as a group of different species than when individual species decompose alone, but underlyingmechanisms of these diversity effects remain poorly understood. Because resource C : N: P stoichiometry (i.e. the ratios of these key elements) exhibits strong control on consumers, we supposed that stoichiometric dissimilarity of litter mixtures (i.e. the divergence in C : N: P ratios among species) improves resource complementarity to decomposers leading to faster mixture decomposition. We tested this hypothesis with: (i) a wide range of leaf litter mixtures of neotropical tree species varying in C : N: P dissimilarity, and (ii) a nutrient addition experiment (C, N and P) to create stoichiometric similarity. Litter mixtures decomposed in the field using two different types of litterbags allowing or preventing access to soil fauna. Litter mixture mass loss was higher than expected from species decomposing singly, especially in presence of soil fauna. With fauna, synergistic litter mixture effects increased with increasing stoichiometric dissimilarity of litter mixtures and this positive relationship disappeared with fertilizer addition. Our results indicate that litter stoichiometric dissimilarity drives mixture effects via the nutritional requirements of soil fauna. Incorporating ecological stoichiometry in biodiversity research allows refinement of the underlying mechanisms of how changing biodiversity affects ecosystem functioning.
ISSN: 0962-8452

hal-01204222
https://hal.archives-ouvertes.fr/hal-01204222
DOI : 10.1098/rspb.2014.1682
PRODINRA : 289918

Éditeur(s) : HAL CCSD
Résumé : International audience
In two swordtail species of the genus Xiphophorus, the onset of puberty has been shown to be modulated at the P locus by sequence polymorphism and gene copy-number variation affecting the type 4 melanocortin hormone receptor Mc4r. The system works through the interaction of two allelic types, one encoding wild type and the other dominant-negative receptors. We have analyzed the structure and evolution of the P locus in the platyfish Xiphophorus maculatus, where as many as nine alleles of P determining the onset of sexual maturity in males and females, fecundity in females, and adult size in males are located on both the X and Y chromosomes in a region linked to the master sex-determining locus. In this species, mc4r has been amplified to up to 10 copies on both the X and Y chromosomes through recent large serial duplications. Subsequently, mc4r paralogues have diverged considerably into many different subtypes. Certain copies have acquired new untranslated regions through genomic rearrangements, and transposable element insertions and other mutations have accumulated in promoter regions, possibly explaining observed deviations from the classical mc4r transcriptional pattern. In the mc4r-coding sequence, in-frame insertions and deletions as well as nonsense and missense mutations have generated a high diversity of Mc4r-predicted proteins. Most of these variants are expressed in embryos, adults, and/or tumors. Functional receptor characterization demonstrated major divergence in pharmacological behavior for Mc4r receptors encoded by different copies of platyfish mc4r, with differences in constitutive activity as well as binding and stimulation by hormones. The high degree of allelic and copy-number variation observed between individuals can explain the high level of polymorphism for sexual maturation, fecundity, and body size in the platyfish: multiple combinations of Mc4r variants with different biochemical properties might interact to modulate the melanocortin signaling that regulates the hypothalamus-pituitary-gonadal axis.
GENETICS

hal-01544912
https://hal.archives-ouvertes.fr/hal-01544912
DOI : 10.1534/genetics.113.155952