Éditeur(s) : Public Library Science
Résumé : Background: The Astrophorida (Porifera, Demospongiae(rho)) is geographically and bathymetrically widely distributed. Systema Porifera currently includes five families in this order: Ancorinidae, Calthropellidae, Geodiidae, Pachastrellidae and Thrombidae. To date, molecular phylogenetic studies including Astrophorida species are scarce and offer limited sampling. Phylogenetic relationships within this order are therefore for the most part unknown and hypotheses based on morphology largely untested. Astrophorida taxa have very diverse spicule sets that make them a model of choice to investigate spicule evolution. Methodology/Principal Findings: With a sampling of 153 specimens (9 families, 29 genera, 89 species) covering the deep- and shallow-waters worldwide, this work presents the first comprehensive molecular phylogeny of the Astrophorida, using a cytochrome c oxidase subunit I (COI) gene partial sequence and the 59 end terminal part of the 28S rDNA gene (C1-D2 domains). The resulting tree suggested that i) the Astrophorida included some lithistid families and some Alectonidae species, ii) the sub-orders Euastrophorida and Streptosclerophorida were both polyphyletic, iii) the Geodiidae, the Ancorinidae and the Pachastrellidae were not monophyletic, iv) the Calthropellidae was part of the Geodiidae clade (Calthropella at least), and finally that v) many genera were polyphyletic (Ecionemia, Erylus, Poecillastra, Penares, Rhabdastrella, Stelletta and Vulcanella). Conclusion: The Astrophorida is a larger order than previously considered, comprising ca. 820 species. Based on these results, we propose new classifications for the Astrophorida using both the classical rank-based nomenclature (i.e., Linnaean classification) and the phylogenetic nomenclature following the PhyloCode, independent of taxonomic rank. A key to the Astrophorida families, sub-families and genera incertae sedis is also included. Incongruences between our molecular tree and the current classification can be explained by the banality of convergent evolution and secondary loss in spicule evolution. These processes have taken place many times, in all the major clades, for megascleres and microscleres.
Plos One (1932-6203) (Public Library Science), 2011-04 , Vol. 6 , N. 4 , P. -

Droits : 2011 Ca´rdenas et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
http://archimer.ifremer.fr/doc/00137/24817/22903.pdf
DOI:10.1371/journal.pone.0018318
http://archimer.ifremer.fr/doc/00137/24817/

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
Alpine Corsica consists of a stack of variably metamorphosed units of continental and Tethys-derived rocks. It represents an excellent example of high-pressure (HP) orogenic belt, such as the Western Alps, exposed over a small and accessible area. Compared to the Western Alps, the geology of Alpine Corsica is poorly unraveled. During the 1970s-80s, based on either lithostratigraphic or metamorphic field observations, various classifications of the belt have been proposed, but these classifications have been rarely matched together. Furthermore, through time, the internal complexity of large domains has been progressively left aside in the frame of large-scale geodynamic reconstructions. As a consequence, major open questions on the internal structure of the belt have remained unsolved. Apart from a few local studies, Alpine Corsica has not benefited of modern developments in petrology and basin research. This feature results in several uncertainties when combining lithostratigraphic and metamorphic patterns and, consequently, in the definition of an exhaustive architecture of the belt. In this paper we provide a review on the geology of Alpine Corsica, paying particular attention to the available lithostratigraphic and metamorphic classifications of the metamorphic terranes. These data are completed by a new and exhaustive metamorphic dataset obtained by means of thermometry based on Raman Spectroscopy of Carbonaceous Material (RSCM). This technique provides reliable insights on the peak temperature of the metamorphic history for CM-bearing metasediments. A detailed metamorphic characterization of metasediments, which have been previously largely ignored due to retrogression or to the lack of diagnostic mineralogy, is thus obtained and fruitfully coupled with the available lithostratigraphic data. Nine main tectono-metamorphic units are defined, from subgreenschist (ca. 280-300 °C) to the lawsonite-eclogite-facies (ca. 500-550 °C) condition. These units are homogeneous in metamorphism, laterally continuous and have characteristic lithostratigraphic features. This study also suggests a direct link between the pre-orogenic extensional setting and the present-day compressional structure of Alpine Corsica, indicating that large sections of subducted lithosphere were subducted and exhumed as coherent domains. These features provide important insight on the mechanism of stacking and exhumation of HP rocks, and make Alpine Corsica a unique reference for mountain-building processes in Tethyan-type orogens.
ISSN: 0012-8252

hal-00814433
https://hal.archives-ouvertes.fr/hal-00814433
DOI : 10.1016/j.earscirev.2012.10.003

Éditeur(s) : HAL CCSD Springer Verlag/EDP Sciences
Résumé : Le développement de modèles de dynamique forestière adaptés aux forêts tropicales humides est compliqué par la très grande diversité spécifique caractérisant ces forêts. Les modélisateurs ont souvent eu recours, pour simplifier le problème, à des techniques de regroupement d'espèces. Il existe des méthodes diverses de regroupement, qui relèvent de trois grands types de stratégie : (i) stratégie écologique subjective, (ii) stratégie écologique basée sur l'analyse de données, (iii) stratégie des processus de dynamique populationnelle. Dans le cadre des deux premières stratégies, une espèce est affectée à un groupe et un seul alors que dans le cadre de la troisième, des groupes d'espèces sont définis pour chacun des processus de dynamique (recrutement, croissance, mortalité) pris séparément, et chaque espèce est affectée à trois groupes. Dans la littérature, on trouve peu d'exemples de congruence ou de convergence entre les groupes définis par ces différentes méthodes. Ceci peut être expliqué par l'indépendance existant entre les caractères utilisés pour fabriquer tel ou tel groupe, ou encore par la grande variabilité intra-spécifique de ces caractères. Nous argumentons et concluons sur le fait que le recours à la stratégie des processus de dynamique paraît être la meilleure pour construire des groupes d'espèces adaptés à la prédiction de la dynamique des forêts tropicales.
ISSN: 1286-4560

hal-01032060
https://hal.archives-ouvertes.fr/hal-01032060
DOI : 10.1051/forest:2005084

Résumé : La dengue constitue actuellement l'arbovirose la plus répandue sur la planète avec 40% de la population mondiale exposée, soit environ 2,5 milliards de personnes. La maladie est endémique dans tous les continents excepté l'Europe même si les premiers cas de transmission autochtone ont été observés en France métropolitaine et en Croatie en 2010. L'augmentation régulière de son incidence fait actuellement de la dengue un problème de santé publique majeur dans les pays tropicaux et une menace pour d'autres pays du monde. En raison de son mode de transmission, la dengue constitue une maladie étroitement liée à l'environnement. L'urbanisation constitue un facteur important dans l'émergence ou la réémergence d'épidémies de dengue dans les pays tropicaux. Cette étude menée a pour objet d'analyser les liens existant entre le domaine de la santé (situation sanitaire et épidémiologique de la dengue) et de celui de l'environnement (évolution de l'urbanisation) en Guadeloupe continentale entre 2000 et 2008.Pour ce faire, les cas suspects et confirmés de dengue ont été recueillis. L'incidence pour ces deux types de cas a été calculée puis représentée à deux échelles administratives différentes: communes et sections. Les facteurs environnementaux comprenant les variables physiques et socio-démographiques ont été pris en compte pour la définition, l'identification et l'analyse de l'évolution des contextes d'habitation durant la période étudiée. Deux méthodes ont été utilisées: la classification «Raster» consistant en une analyse régulière basée sur des mailles de taille identique et la classification « Vecteur» s'appuyant sur les limites administratives des sections. Ces classifications ont permis de décrire la répartition des différents contextes d'habitation sur le territoire de la Guadeloupe et d'obtenir des indicateurs qui ont été analysés en relation avec les données sanitaires. Il a été mis en évidence que la situation épidémiologique de la dengue dans le département s'est significativement aggravée au cours de la période étudiée. Des épidémies majeures sont apparues en 2001, 2005/2006 et 2007. Le nord Basse-Terre, la région Pointoise ainsi que le sud-est de la Grande-Terre, de la ville du Gosier à Saint-François le long de la côte, sont les régions les plus concernées par l'augmentation d'incidence de la maladie. Concernant les contextes d'habitation, huit contextes distincts ont été identifiés: touristique, naturel, intermédiaire, agricole, résidentiel, rural, périurbain et urbain. Le contexte intermédiaire correspond à des régions de transition entre les autres contextes d'habitation. La différence entre les contextes agricoles et ruraux réside dans la prédominance de surface agricole pour le premier alors que le contexte rural est caractérisé par les espaces cultivés habités. L'évolution surfacique de ces contextes au cours du temps a été analysée en relation avec les incidences. Les résultats montrent que les contextes d'habitation sont statistiquement.associés à l'incidence de la dengue en Guadeloupe. En particulier, les contextes touristiques, résidentiels et ruraux possèdent une association positive élevée avec l'incidence de la dengue.
At present, dengue fever has become the arbovirose the most wide-spread worldwide with 40 % ofthe exposed population, 2,5 billion people. The disease is endemie in all the continents excepted Europe even though the fust cases ofautochthonoustransmissionwere observedinmetropolitanFranceandCroatiain2010.Because oftherecentincrease of its incidence, dengue fever is now a major public health problem in the tropical countries and a threat for the other countries in the worldwide. Due to its mode oftransmission, the disease is closely linked to the environment. Urbanization is an important factor ofthe emergence or the re-emergence of dengue in the tropical countries. This study aims to analyze the links between health and environment domains, which correspond to the epidemiological situation of the dengue and the evolution ofthe urbanization in Guadeloupe.Information about suspect and confirmed cases of dengue were collected. The incidence of suspect and confirmed cases has been estimated, then represented at two different administrative boundaries: communes and sections. Environmental factors including the physical and socio-demographic variables were taken into account to the definition, the identification and the analyze ofevolution of the housing patterns during the studied period. Two methods were used: Il Raster" consisting of a regular analysis based on squares units and "Vector" based on the administrative limits of sections. These classifications allowed to describe the distribution ofthe different housing patterns ofGuadeloupe and to estimate indicators for the analyzing of sanitary data. The results highlight a worsening ofepidemiological situation ofthe dengue over the time in the department. Major outbreaks occurred in 2001,2005/2006 and 2007. The north Basse-Terre, the Pointe-à-Pitre urban area as weIl as the whole coast (frOID the city of Gosier to Saint-François) ofthe southeast ofGrande-Terre were the most affected regions by the increase ofincidence of dengue. Concerning the housing classes, eight different patterns were identified: tourist, natural, intermediate, agricultural, residential, rural, suburban and urban. The intermediate class corresponds to buffer regions between the other patterns. The difference between the agricultural and rural contexts lies in the predominance ofagricultural surface for the first one while the rural context is characterized by the inhabited farmland. The evolution over time of spatial extend ofthese patterns was described in relation with incidence. Results showed that the housing patterns are statically associated with the incidence ofdengue in Guadeloupe. In particular, the touristic, residential and rural patterns have a high positive association with dengue incidence.

http://www.theses.fr/2012AGUY0565/document

Éditeur(s) : HAL CCSD Springer Verlag
Résumé : International audience
Heartwood/sapwood profile and the tradeoff between trunk and crown increment in a natural forest: the case study of a tropical tree (Dicorynia guianensis Amsh., Fabaceae) Key message Sapwood area and the radial growth rate of the trunk follow the same pattern at breast height, with an initial increase and subsequent constant value, resulting from the increasing growth allocation toward the crown rather than tree decline. Heartwood area and heartwood volume in the trunk increase more rapidly after this shift occurs. Abstract Sapwood (SW) and heartwood (HW) are two functionally distinct classifications of wood in perennial stems for which quantities can vary greatly in tropical trees. Numerous positive correlations have been found between the radial growth rate (RGR) and SW quantity; however, variations in the SW/HW quantities have not been studied in light of the ontogenetic variation of RGR. Wood core sampling, intensive measurements of tree structure (number of branches, stem volumes), and radial growth monitoring were performed on an abundant and highly exploited tree species in French Guiana (Dicorynia guianensis) to investigate the relationship between RGR, SW/HW quantity, tree structure, and their variations on the course of a tree's ontogeny. SW area and RGR followed the same pattern of variation throughout tree development, both increasing first and reaching a steady state after 50 cm DBH (diameter at breast height). After this value, we observed a strong increase in both the HW area and HW volume increment, concomitant with a more rapid increase in crown volume. The stabilization of RGR for trees with DBH >50 cm was related not to a tree's decline but rather to an increasing wood allocation to the crown, confirming that RGR at breast height is a poor indicator of whole-tree growth for bigger individuals. We also confirmed that HW formation is an ontogenetic process managing SW quantity that is continuously and increasingly produced within the crown as the tree grows. This study highlights the effect of growth-mediated ontogenetic changes on the localization of water and carbohydrate storage within a tree, resulting from SW and HW dynamics throughout tree ontogeny.
ISSN: 0931-1890

hal-01654003
https://hal.archives-ouvertes.fr/hal-01654003
https://hal.archives-ouvertes.fr/hal-01654003/document
https://hal.archives-ouvertes.fr/hal-01654003/file/Lehnebach%20et%20al.%E2%80%94Trees%202016-%20Own%20version.pdf
DOI : 10.1007/s00468-016-1473-7

Éditeur(s) : HAL CCSD
Résumé : International audience
Tension wood, a tissue developed by angiosperm trees to actively recover their verticality, has long been defined by the presence of an unlignified cellulosic inner layer in the cell wall of fibres, called the G-layer. Although it was known that some species have no G-layer, the definition was appropriate since it enabled easy detection of tension wood zones using various staining techniques for either cellulose or lignin. For several years now, irrespective of its anatomical structure, tension wood has been defined by its high mechanical internal tensile stress. This definition enables screening of the diversity of cell walls in tension wood fibres. Recent results obtained in tropical species with tension wood with a delay in the lignification of the G-layer opened our eyes to the effective presence of large amounts of lignin in the G-layer of some species. This led us to review older literature mentioning the presence of lignin deposits in the G-layer and give them credit. Advances in the knowledge of tension wood fibres allow us to reconsider some previous classifications of the diversity in the organisation of the fibre walls of the tension wood.
ISSN: 0928-1541

hal-01636686
https://hal.archives-ouvertes.fr/hal-01636686
https://hal.archives-ouvertes.fr/hal-01636686/document
https://hal.archives-ouvertes.fr/hal-01636686/file/2017_Ghislain-Clair_IAWAJ_DiversityOrganisationLignificationTensionWoodFibreWalls-AReview.pdf
DOI : 10.1163/22941932-20170170

Éditeur(s) : HAL CCSD Coastal Education and Research Foundation
Résumé : Nearshore bars are generally present on sandy coasts and play a significant role in wave breaking and sediment exchange between beach and shoreface. The study area is located on the Languedoc-Roussillon coast in the Gulf of Lions (southern part of the French Mediterranean coast). This microtidal environment is classified as a wave-dominated coast. The sand coast displays different bar systems (single or multiple; straight or crescentic). The alongshore variability of bar morphology in the nearshore zone was investigated in August 2009 during one week, using a topo-bathymetric LIDAR data set (300 km(2)). LIDAR makes it possible to cover a large area in a very short time with a high resolution. The topo-bathymetric LIDAR offers the added benefit of morphological information about the beach-sea transition in very shallow water (below I in), data often difficult if not impossible to obtain with traditional techniques. The purpose of this paper is 1) to depict the distribution of bars and their characteristics along the 180 km coast of the Gulf of Lions; 2) to update the classifications of sand bars typologies in Languedoc-Roussillon; 3) to pay particular attention to the description of the intricate inner system. Globally, cross-shore distribution of subtidal morphologies is characterized by both an outer and an inner system. The outer system is crescent-shaped in the south and straight in the northern part with a distinctive regional delimitation. The inner system comprises an inner bar and, near the coast, a complex fluctuating bar called Low Bar Beach (LBB). Several intermediate states were identified and added to the new classification proposed in this paper. These results clearly emphasize the importance of LIDAR technology for a better understanding of bar behaviour and single and/or multi-bar beach organisation.
ISSN: 0749-0208

hal-00783187
https://hal.archives-ouvertes.fr/hal-00783187