Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
The emerging orbicular batfish (Platax orbicularis) aquaculture is the most important fish aquacultureindustry in French Polynesia. However, bacterial infections are causing severe mortality episodes.Therefore, there is an urgent need to find an effective management solution. Besides the supplyingdifficulty and high costs of veterinary drugs in French Polynesia, batfish aquaculture takes place close tothe coral reef, where use of synthetic persistent drugs should be restricted. Medicinal plants andbioactive algae are emerging as a cheaper and more sustainable alternative to chemical drugs. We havestudied the effect of local Polynesian plants and the local opportunistic algae Asparagopsis taxiformis onbatfish when orally administered. Weight gain and expression of two immune-related genes (lysozyme ge Lys G and transforming growth factor beta - TGF-b1) were studied to analyze immunostimulant activityof plants on P. orbicularis. Results showed that several plants increased Lys G and TGF-b1 expressionon orbicular batfish after 2 and 3 weeks of oral administration. A. taxiformis was the plant displaying themost promising results, promoting a weight gain of 24% after 3 weeks of oral administration andsignificantly increasing the relative amount of both Lys G and TGF-b1 transcripts in kidney and spleen ofP. orbicularis.
ISSN: 1050-4648

hal-01381334
https://hal-univ-perp.archives-ouvertes.fr/hal-01381334
DOI : 10.1016/j.fsi.2016.09.011

Éditeur(s) : HAL CCSD Elsevier
Résumé : The relationship between deformation and so-called fluid paleotransfers in minor faults has been analysed in an argillaceous formation located in the Causses Basin in France. The fluid paleotransfers are related to the fault activity to a large extent. We attempt to estimate the intensity of paleo-deviatoric stress magnitudes under which the fault activity may have occurred and consequently, the change in the structural fault permeability. The paleo-deviatoric stress magnitudes were calculated with the inverse method of Etchecopar applied to calcite twinning. The measured crystals are contained within the core zone of minor faults and this study is based on a previous complete microtectonic and microstructural analysis of the faults. In this paper, analysis of calcite twinning has been applied for the first time to vein fillings associated small faults in a context of relatively weak deformation, a condition ensured by the tectonic and structural analysis. Calculation and discussion of the paleo-deviatoric stress tensors in relation to the evolution of the structural fault permeability and to the hydraulic behaviour of the faults are the aim of this paper. The analysed faults, created and active during the same tectonic event, were permeable under a (;σ;1;–;σ;3;) mean value of 40–50 MPa. On the other hand, the reactivation of faults during a second tectonic event implies mean (;σ;1;–;σ;3;) value higher than 40–50 MPa, especially for the faults that are poorly oriented with respect to the principal tectonic stress directions. The core zone of these faults remained sealed and impermeable or became permeable by development of microcracks inside the pre-existing fillings.
ISSN: 0040-1951

hal-00407577
https://hal.archives-ouvertes.fr/hal-00407577
DOI : 10.1016/j.tecto.2006.09.014

Éditeur(s) : HAL CCSD Oxford University Press (OUP)
Résumé : International audience
STUDY QUESTION: Can protein biomarkers of the male genital tract be identified in human seminal plasma? SUMMARY ANSWER: We identified potential biomarkers for each of the organs participating in the secretions of the human seminal plasma. WHAT IS KNOWN ALREADY: The seminal plasma fulfills critical functions for fertility by providing spermatozoa with a protective milieu, promoting their final maturation and modulating the immune responsiveness of the female reproductive tract. It is also considered to be a promising source of biomarkers of male infertility and/or pathologies of the male genital tract. STUDY DESIGN, SIZE, DURATION: This study combines proteomic analyses of normal seminal plasma together with transcriptomic gene expression profiling of human healthy tissues. MATERIALS, SETTING, METHODS: Non-liquefied seminal plasma proteins from a healthy donor were prefractionated using two sequential Proteominer™ libraries. Eight subproteome fractions were collected, trypsin digested and subjected to three successive mass spectrometry analyses for peptide characterization. The list of identified proteins was compared with and merged with other available data sets of the human seminal plasma proteome. The expression of corresponding genes was then investigated using tissue transcriptome profiles to determine where, along the male reproductive tract, these proteins were produced. Finally, tissue specificity of a selected subset of biomarker candidates was validated on human tissues. MAIN RESULTS AND THE ROLE OF CHANCE: We first performed a proteomic analysis of the human seminal plasma and identified 699 proteins. By comparing our protein list with other previous proteomic data sets, we found that 2545 unique proteins have been described so far in the human seminal plasma. We then profiled their expression at the gene level and identified 83 testis, 42 epididymis, 7 seminal vesicle and 17 prostate candidate protein markers. For a subset of testis-specific candidates, i.e. TKTL1, LDHC and PGK2, we further validated their germ cell expression and demonstrated that such markers could distinguish between semen from fertile and infertile men. LIMITATIONS, REASONS FOR CAUTION: While some of the markers we identified are well-known tissue-specific products, further dedicated studies to validate the biomarker status of new candidates will be required. Additionally, whether or not the abundance of these proteins is indeed decreased in some specific pathological situations remains to be determined. WIDER IMPLICATIONS OF THE FINDINGS: Using an integrative genomics approach, we identified biomarker candidates for each of the organs participating in the seminal plasma production. In this study, we essentially focused on germ cell markers and their potential application for the diagnosis of male infertility. Other types of markers also deserve a focused attention given their potential predictive value for various reproductive disorders, notably for prostate cancers. STUDY FUNDING/COMPETING INTEREST(S): This work was supported by the Proteomics Core Facility at Biogenouest and was funded by Conseil Régional de Bretagne, IBiSA and Agence de la Biomédecine grants. The authors declare that there exists a competing financial interest in this work that is related to a patent application on the use of identified germ cell-specific proteins in an antibody-based assay (Fertichip™) to predict the successful testicular biopsy outcomes in human non-obstructive azoospermia.
ISSN: 0268-1161

inserm-00814146
http://www.hal.inserm.fr/inserm-00814146
DOI : 10.1093/humrep/des360
PUBMED : 23024119

Éditeur(s) : HAL CCSD European Geosciences Union (EGU)
Résumé : International audience
Holocene climate fluctuations and human activity since the Neolithic have shaped present-day Mediter-ranean environments. Separating anthropogenic effects from climatic impacts to better understand Mediterranean pale-oenvironmental changes over the last millennia remains a challenging issue. High-resolution pollen analyses were un-dertaken on two cores from the Palavasian lagoon system (Hérault, southern France). These records allow reconstruction of vegetation dynamics over the last 4500 years. Results are compared with climatic, historical and archeological archives. A long-term aridification trend is highlighted during the late Holocene, and three superimposed arid events are recorded at 4600–4300, 2800–2400 and 1300–1100 cal BP. These periods of high-frequency climate variability coincide in time with the rapid climatic events observed in the Atlantic Ocean (Bond et al., 2001). From the Bronze Age (4000 cal BP) to the end of the Iron Age (around 2000 cal BP), the spread of sclerophyllous taxa and loss of forest cover result from anthropogenic impact. Classical Antiquity is characterized by a major reforestation event related to the concentration of rural activity and populations in coastal plains leading to forest recovery in the mountains. A major regional deforestation occurred at the beginning of the High Middle Ages. Around 1000 cal BP, forest cover is minimal while the cover of olive, chestnut and walnut expands in relation to increasing human influence. The present-day vegetation dominated by Mediterranean shrubland and pines has been in existence since the beginning of the 20th century.
ISSN: 1814-9324

hal-01447627
https://hal-univ-tlse2.archives-ouvertes.fr/hal-01447627
https://hal-univ-tlse2.archives-ouvertes.fr/hal-01447627/document
https://hal-univ-tlse2.archives-ouvertes.fr/hal-01447627/file/Azuara%20et%20al%202015_cor.pdf
DOI : 10.5194/cp-11-1769-2015

Éditeur(s) : HAL CCSD Elsevier
Résumé : SUBSURF
Statistical sequential analysis was performed on a series of sediment cores collected from the Têt prodelta in the Gulf of Lions, northwestern Mediterranean Sea, between October 2003 and October 2004. Seabed changes during that period were correlated to hydrodynamic conditions (waves and currents) and river discharge. Low sediment supply prevents full preservation of new sediment strata on this low-accumulation prodelta located on a microtidal, storm-dominated inner shelf. Severe meteorological events caused a rapid succession of erosion and deposition phases. For example, the December 2003 flood and storm produced a flood layer deposit that persisted for 2 months with only slight transformations due to early diagenesis and/or bioturbation, until a new storm event eroded this layer. A typical sedimentary sequence was observed for the secular deposits composed of a 10-cm-thick sandy layer overlaying siltyclayey layers. These characteristic features were used to analyse the last millennia sedimentary record of the Têt prodelta. The low preservation of freshly deposited sediments and variable sedimentation rates during the last millennia period yield a sedimentary sequence formed by the outcropping of muddy prodeltaic units intersected by heterogeneous siltysandy units similar to those formed under present day hydrodynamic conditions. No flood layer was found related to catastrophic flooding of the last century in the sedimentary record. The Little Ice Age ( 1550–1850 AD) probably favoured the formation of a well-developed muddy prodelta in the mouth of the Têt River. Later on, the decrease of sediment supply by rivers due to climate change and/or human activities (damming, irrigation), and the increase of the number of high-energy storms reaching the coast, induced a coarsening of the top sediment layer on this prodelta. This modern change of the substrate is also observed in the composition of benthic biota found in the substrate
ISSN: 0025-3227

hal-00407662
https://hal.archives-ouvertes.fr/hal-00407662
DOI : 10.1016/j.margeo.2007.04.009

Éditeur(s) : HAL CCSD Société géologique de France
Résumé : International audience
The central part of the Gulf of Lions shoreline is characterized by many coastal wetlands that resulted from the interaction between a process of shoreline regularization by migrations of littoral barriers and a slow filling of the back-barrier areas by the riverine and marine inputs. Analyses of Late-Holocene deposits with a very high-resolution multi-proxy study of two sediment cores, allow us to reconstruct the evolution of this coastal system. Two main Holocene sediment units are identified overlying a Pliocene carbonate continental formation. The lower unit consists of sandy and pebbly marine sediments deposited around 7800 B.P., during the final stand of the last sea level rise. Just above, the upper unit displays lagoonal grey clay silts with shells and some intercalated layers of silty sands related to paleostorm events. The age model was established from radiocarbon dating, for the oldest part of the core. Over the last century, sedimentation rates were calculated using the CFCS Pb-210 model, together with Cs-137 data. Radiocarbon data show an increase in he accumulation rate from the base to the top of cores. Marine sand units related to the last transgressive deposit allow to refine the curve of Holocene post-glacial sea level rise. Sedimentological and faunal analyses associated with chronological data provide a means for reconstructing the Late-Holocene paleoenvironments along this part of the coast and suggest that the final closure of the coastal lagoon by the sandy barrier occurred at around 730 +/- 120 yr cal B.P. The beginning of this closure, together with the progradation of the coastal plain, could be responsible for the decline in economic activity of the Lattara harbour during the Roman period.
La partie centrale du littoral du golfe du Lion est caractérisée par de nombreuses lagunes qui résultent de l'interaction entre un processus de régularisation du trait de côte par migration de barrières littorales et d'un lent remplissage des zones situées en arrière des barrières par des apports continentaux et marins. Les analyses des dépôts tardi-holocènes avec une étude multi-traceurs à très haute résolution de deux carottes sédimentaires nous permettent de reconstruire l'évolution de ce système côtier. Deux unités sédimentaires holocènes sont identifiées recouvrant une formation pliocène carbonatée. L'unité inférieure est constituée de sables et de galets d'origine marine déposés vers 7800 B.P., durant les stades ultimes de la dernière remontée marine. Audessus, l'unité supérieure montre des dépôts d'argile et de silt gris coquilliers d'origine lagunaire, dans lesquels sont intercalés des niveaux de sable silteux révélant la présence d'événements de tempêtes. Le modèle d'âge est établi à partir de dates radiocarbones pour les parties les plus anciennes des archives sédimentaires, tandis que pour le dernier siècle, les taux de sédimentation sont calculés en utilisant le modèle CFCS pour le 210Pb, associé aux données de 137Cs. Les données 14C montrent une augmentation du taux d'accumulation depuis la base jusqu'en surface des carottes. Les unités de sables marins liées aux dépôts de la dernière transgression marine permettent de préciser la courbe post-glaciaire de remontée du niveau marin. Les analyses sédimentologiques et faunistiques associées aux données chronologiques fournissent une méthode permettant de reconstituer les paléoenvironnements littoraux tardi-holocènes dans la zone d'étude et suggèrent que la fermeture finale de ces lagunes par le cordon sableux survient autour de 730 ± 120 ans cal B.P. Le début de cette fermeture, associée à la une progradation deltaïque, pourrait être responsable du déclin des activités économiques du port de Lattara durant la période Romaine.
EISSN: 1777-5817

halshs-00740923
https://halshs.archives-ouvertes.fr/halshs-00740923
DOI : 10.2113/gssgfbull.181.1.27

Éditeur(s) : HAL CCSD American Geophysical Union (AGU)
Résumé : International audience
We studied the patterns, rates and evolution of fluvial terraces and fault system during the building process of an intracontinental transpressional mountain in the Gobi-Altay (Mongolia). By analyzing incisions and offsets of fluvial terraces and alluvial fans, we show that the massif has grown by outward migration of thrust faults through time. On the northern flank, the present bounding thrust fault began its activity ~600 ka ago, while a more internal sub-parallel fault was still active until ~200-100 ka. Vertical offset of an alluvial fan abandoned ~100 ka ago allows an estimate of 0.1 mm/yr Upper Pleistocene - Holocene uplift rate. The morphology of the catchment-piedmont system strongly suggests a periodical formation of the alluvial surfaces, controlled by the climatic pulses, at the beginning of the wet interglacial periods. The abandonment of the alluvial terraces lags by several thousand years the abandonment of the alluvial fans, showing a diachronous incision propagating upstream. The incision rate deduced from the different elevations of straths exceeds of one order of magnitude the rock uplift rate. This excess is mostly due to ongoing drainage network growth at the core of the massif, and incision due to alluvial apron entrenchment near the outlet. This implies that fluvial response is mainly controlled by drainage growth, interaction with piedmont and cyclic climatic variations, rather than by rock uplift.
ISSN: 0278-7407

hal-00323558
https://hal.archives-ouvertes.fr/hal-00323558
https://hal.archives-ouvertes.fr/hal-00323558v2/document
https://hal.archives-ouvertes.fr/hal-00323558/file/Vassallo2007.pdf
DOI : 10.1029/2006TC002081

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
The Grande Terre of New Caledonia is enclosed by one of the longest barrier reefs in the world. For the first time, the fore-reef slopes of this barrier reef have been sampled by dredging, from 40 to 320 m deep, in order to analyze their sedimentological and biological characteristics. The rocks and sediments can be divided into seven sedimentary facies: bindstones dominated by coralline algal crusts, bindstones dominated by foraminiferal crusts, bindstones dominated by bryozoan crusts, coral framestones, bindstones and interstratified packstones rich in skeletal debris, packstones/wackestones and grainstones rich in rock gravels. Radiocarbon dating performed on encrusting organisms (coralline algae and acervulinids) and corals provide ages relatively young. These ages confirm that the encrusting organisms are modern and the corals mainly dated of Holocene are reworked due to the instability of the fore-reef slopes, especially during storms. Because the biological assemblages are distributed according to a bathymetric range depending on light intensity, a model of distribution of modern encrusting calcareous organisms can be proposed from our observations and analyses. From the upper reef slopes to approximately 90 m, thick coralline algal crusts are dominant and distributed in three groups. Group C, the shallowest parts of the fore slopes, is mainly characterized by mastophorids (Hydrolithon reinboldii, H. cf. munitum, Lithoporella melobesoides, Aethesolithon cf. problematicum, Neogoniolithon sp. and undetermined species) and lithophylloids (Lithophyllum sp., L. pustulatum). Group B, composed of lithophylloids (Lithophyllum sp., L. cf. kotschyanum, L. cf. moluccence, L. pustulatum), Mesophyllum sp. and Peyssonnelia sp. occurs from 15 to 40 m. Group A, rich in Mesophyllum sp., M. cf. mesomorphum, Peyssonnelia sp. and Sporolithon sp. is characteristic of deep reef slopes up to 90 m. Below approximately 90 m, when the light intensity decreases, the encrusting foraminifera acervulinids progressively replace the coralline algal crusts. Such a model is particularly useful to interpret and reconstruct the past Quaternary reef environments rich in crusts of coralline algae and/or foraminifera.
ISSN: 0025-3227

hal-00393705
https://hal.archives-ouvertes.fr/hal-00393705
DOI : 10.1016/j.margeo.2007.12.002

Éditeur(s) : HAL CCSD Copernicus Publications on behalf of the European Geosciences Union
Résumé : International audience
During the GWADASEIS cruise (Lesser Antilles volcanic arc, February–March 2009) a very high resolution (VHR) seismic-reflection survey was performed in order to constrain Late Quaternary to Present faulting. The profiles we obtained evidence frequent " ponding " of reworked sediments in the deepest areas, similar to the deposition of Mediterranean " homogenites ". These bodies are acoustically transparent (few ms t.w.t. thick) and are often deposited on the hanging walls of dominantly normal faults, at the base of scarps. Their thickness appears sufficient to compensate (i.e. bury) co-seismic scarps between successive earthquakes, resulting in a flat and horizontal sea floor through time. In a selected area (offshore Montserrat and Nevis islands), piston coring (4 to 7 m long) was dedicated to a sedimento-logical analysis of the most recent of these particular layers. It corresponds to non-stratified homogenous calcareous silty sand (reworked calcareous plankton and minor volcanoclas-tics). This layer can be up to 2 m thick, and overlies fine-grained hemipelagites. The upper centimeters of the latter represent the normal RedOx water/sediment interface. 210 Pb and 137 Cs activities lack in the massive sands, while a normal profile of unsupported 210 Pb decrease is observed in the hemipelagite below, together with a 137 Cs peak corresponding to the Atmospheric Nuclear Experiments (1962). The RedOx level was thus capped by a recent instantaneous major sedimentary event considered as post-1970 AD; candidate seismic events to explain this sedimentary deposits are either the 16 March 1985 earthquake or the 8 October 1974 one (M w = 6.3 and M w = 7.4, respectively). This leads to consider that the syntectonic sedimentation in this area is not continuous but results from accumulation of thick homogen-ites deposited after the earthquakes (as observed in the following weeks after Haiti January 2010 event, McHugh et al., 2011). The existence of such deposits suggests that, in the area of study, vertical throw likely results from cu-mulated effects of separated earthquakes rather than from aseismic creep. Examination of VHR profiles shows that all major co-seismic offsets are recorded in the fault growth sequence and that co-seismic offsets can be precisely estimated. By using a sedimentation rate deduced from 210 Pb decrease curve (0.5 mm yr −1) and taking into account minor reworking events detected in cores, we show that the Redonda system may have been responsible for five > M 6 events during the last 34 000 yr. The approach presented in this work differs from fault activity analyses using displaced sets of isochronous surfaces and postulating co-seismic offsets. Combining VHR seismic imagery and coring we can decipher co-seismic vs. slow continuous displacement, and thus actually estimate the amplitude and the time distribution of major co-seismic offsets.
Natural Hazards and Earth System Science

insu-01585969
https://hal-insu.archives-ouvertes.fr/insu-01585969
https://hal-insu.archives-ouvertes.fr/insu-01585969/document
https://hal-insu.archives-ouvertes.fr/insu-01585969/file/nhess-12-1755-2012-beck.pdf
DOI : 10.5194/nhess-12-1755-2012

Éditeur(s) : EDP Sciences
Résumé : The diversity of reef ecosystems, the multiplicity of reef resource uses and the breadth of the range of the island socio-cultural contexts concerned make coral reef fisheries (CRF) management in the South Pacific a complex task. The health and state of the targeted resources depend both on ecosystem characteristics (as determined by ecological and biological factors) and on fishing pressure, whose effects are only partly known. Increasing harvests from commercial and recreational fishing increasingly overlap with traditional Subsistence activity, creating an important CRF management challenge. This paper presents a new approach to CRF assessment and monitoring by providing a set of multidisciplinary indicators. The fisheries system is assessed from three different viewpoints: ecology of targeted populations, exploitation and the broader socio-econornic fishery context. The use of complementary indicators chosen from each of these fields could balance the chronic lack of human and financial resources for the management of these fisheries. We suggest the use of these indicators through an assessment grid or an indicator dashboard specifically adapted to given situations and management objectives determined through a participatory approach. The operational efficiency of this dashboard depends on i) dialogue between users, ii) the objectivity of the proposed monitoring, iii) the Visual transcription of divergent/convergent interests amongst stakeholders, and iv) stakeholder involvement in the decision-making process. The use and constraints of such a tool are described with reference to Ouvea atoll (New-Caledonia, South Pacific) for which an analysis of available indicators for assessing fisheries status is presented.
La diversité des écosystèmes coralliens, la multiplicité des modalités d'exploitation de leurs ressources et l'hétérogénéité des contextes socio-culturels insulaires rendent complexe la gestion des pêcheries récifo-lagonaires du Pacifique sud. La santé et l'évolution de ces ressources dépendent, d'une part, des caractéristiques propres de l'écosystème (obéissant à des facteurs biologiques et écologiques) et, d'autre part, de la pression de pêche dont certains effets seulement sont établis. La pêche traditionnelle aux fins de subsistance est aujourd'hui concurrencée par des activités à visées commerciales et récréatives, qui accroissent les prélèvements et soulèvent de nouveaux enjeux de gestion. L'article propose une approche pour l'évaluation et le suivi de ces pêcheries basée sur un ensemble d'indicateurs pluridisciplinaires. Le système « Pêche » est analysé de trois points de vue complémentaires : l'écologie des peuplements exploités, l'exploitation halieutique sensu stricto et le contexte économique et social plus large des pêcheries. La mise en place d'indicateurs issus de ces trois domaines vise à compenser le manque chronique de moyens financiers et humains pour la gestion des pêcheries coralliennes des îles du Pacifique sud. Nous suggérons que leur utilisation s'effectue au travers d'une grille d'évaluation ou tableau de bord répondant à des situations précises et des objectifs de gestion définis lors d'une approche participative. La portée opérationnelle de ce tableau de bord de gestion de la pêche repose sur i) la concertation engagée entre les usagers, ii) l'objectivité du suivi préconisé, iii) la transcription visuelle des intérêts convergents et/ou divergents des acteurs, et iv) leur implication dans le processus de décision. Les modalités et contraintes d'application de cet outil sont décrites sur l'exemple de l'atoll d'Ouvéa (Nouvelle-Calédonie, Pacifique Sud), pour lequel une analyse des indicateurs disponibles pour décrire l'état des pêcheries a été réalisée.
Aquatic Living Resources (0990-7440) (EDP Sciences), 2005-07 , Vol. 18 , N. 3 , P. 199-213

Droits : 2005 EDP Sciences, IFREMER, IRD
http://archimer.ifremer.fr/doc/2005/publication-716.pdf
DOI:10.1051/alr:2005026
http://archimer.ifremer.fr/doc/00000/716/

Éditeur(s) : HAL CCSD Laboratoire Arago
Résumé : International audience
The analysis of the C-O stable isotope composition of coral reef fish otoliths from Taiaro, a French Polynesian atoll normally isolated from the Pacific Ocean, has been performed to address two main questions. The first is to confirm previous results which suggest that a lagoonal coral reef fish population is able to achieve its ontogenetic cycle without any open ocean phase. If so, are O isotopic values of otoliths an indicator of temperature fluctuations in the tropical Pacific Ocean related to climate change and in particular temperature variations of water masses? δ18O and δ13C values on both lagoon and open ocean fish otoliths caught in 2006 indicated clearly that O-isotopes reached the isotopic equilibrium; in contrast, all δ13C values exhibited a strong isotopic disequilibrium related to metabolic activity. Stable isotope compositions revealed a clear differentiation between fish from lagoons and those from the open ocean (with a δ18O enrichment of 1 ‰ in favour of the lagoon). This confirmed a lack of connectivity between habitats and that fish from lagoon lived their entire life cycle in the lagoon. Both δ18O and δ13C data indicated differences between nucleus and edge signatures with changes in fish behavior from the larval life to adulthood (habitat, diet, etc.), and a clear adaptation of dietary behavior of lagoon fish. The comparison of the 2006 data set with those of 1994 showed that environmental conditions were stable in the lagoon, leading to a very narrow range of variations in the δ18O values. δ18O of fish otoliths of the open ocean exhibited a wider variation (+0.25 ‰) between 1994 and 2006, suggesting a decrease in temperature linked to a change of SST, which can be interpreted in terms of climate change associated with El Nino Southern Oscilation (ENENSO). These differences could also be due to a switch of habitats during the life cycle of fish from the open ocean.
ISSN: 0240-8759

hal-01162477
https://hal-univ-perp.archives-ouvertes.fr/hal-01162477

Éditeur(s) : HAL CCSD
Résumé : The Franceville Basin (2.1 Ga) in southeastern Gabon, hosts a black shale series well preserved (FB Formation) which represents an exceptional example of unmetamorphised Paleoproterozoic sediment strata. This basin includes the protore of one of the largest Mn-oxide laterite ore worldwide, mined by Eramet-Comilog. The aim of this this work is to determine formation conditions of this protore and to characterize the global sedimentary evolution of the FB Formation which include the protore. This 75 m thick protore is constituted of Mn carbonate-rich black shales which represent a potential ore deposit for the future. It was drilled, on the Bangombé plateau, during a recent campaign of 24 boreholes with an average depth of 125 m.Through multidisciplinary study on these cores and key outcrops of the basin, this work focuses on : i) the depositional environment of the Mn-protore and FB Formation ; ii) the processes of formation of the Mn-carbonates at 2.1 Ga and iii) the architecture and distribution of Mn-rich levels of the protore on the Bangombé Plateau.A detailed sedimentological and petrological study allowed us to redefine the division of the FB into nine units, named U1 to U9 from the base to the top. These units show a fine upward cycle up to U5 and a reverse coarse loop until U9. This division leads to a new interpretation to propose an evolution from a shoreface depositional environment controlled by deltaic currents (U1) to an offshore depositional environment with anoxic conditions (U2). In this basin, a system of submarine fan is developed, feeding a network of sand injections (injectites) covering the Bangombé plateau (70 km²) and with a thickness of 150 m affecting U4 to U7, including the Mn-protore. The protore depositional environment formed below the wave base limit (U4, U5 and U6) in a starved basin, controlled by biochemical sedimentation allowed the formation of Mn-carbonates. The end of starved basin, would allow the re-opening of the detrital input into the offshore basin (U7). This basin is then filled by storm bar deposits intersected by deltaic sub-aquatic channels (U8). The U9 unit corresponds to a quiet lagoon environment, allowing the multicellular organism development for the first time on the planet.A geochemical study allowed the characterization of the depositional environment of Mn-carbonates as an anoxic to sub-oxic and alkaline environment. For the first time, we showed that the manganese carbonates, present as bacteriomorph forms, are precipitated from the seawater by the mediated photosynthetic cyanobacterial activity, which allows CO2 / HCO3 depression of the environment and a local increase of pH. The cyanobacterial activity is controlled by the absence of bottom currents, which increase the detrital input. This would stop the activity of the cyanobacteria and thus would lead to the decrease of the Mn-concentration along the protore.Finally, well-log and a sequential correlation analyses allowed us to detail spatial and timing repartition of FB Formation deposit, controlled by a tectono-sedimentary model. We propose two- tectono-sedimentary phases. A first syn-tectonic phase (U1 to U3) controls the depocentres and sedimentation gaps. Turbidite coarse deposits are located in the most subsident part, clay deposits rather on the slope and carbonates on shoals. A second post-tectonic phase (U4 to U7) allows isopach deposits. The Mn-protore formed during the post-tectonic phase. However, it shows a variable thickness due to subsidence to the north of the Bangombé plateau. So, on the Bangombé plateau, Mn-contents increase towards the south, whereas the protore thickness increases towards the NNE. Moreover sand injectites decrease Mn-content in the eastern part of the Bangombé plateau and impact on the economic evaluation of the Mn-carbonates. Currently, the protore is structured by post-sedimentary faults, which lead to a non-continuity of the high Mn levels on the Bangombé plateau.
Le Bassin de Franceville situé au SE du Gabon présente une série de black shales (Formation FB) d'âge Paléoprotérozoïque (2,1 Ga) surmontant les grès de la Formation FA. Ce bassin peu déformé et non métamorphique représente une archive exceptionnelle des processus de dépôt de cette période de l’histoire de la Terre où la vie commence à se développer. En particulier, la Formation FB contient le protore d'un gisement mondial d'oxydes de manganèse exploité par la société Eramet-Comilog. L’objectif de ce travail est de préciser les conditions de formation de ce protore et de le replacer dans l’histoire du remplissage du bassin. Ce protore d'une épaisseur moyenne de 75 m est constitué de carbonates de manganèse ; il a fait l'objet d'une récente campagne de 24 forages carottés d'une profondeur moyenne de 125 m sur le plateau de Bangombé.A travers une approche pluridisciplinaire comprenant l'étude de ces forages et des affleurements clefs du bassin, ce travail porte sur la caractérisation i) de l'environnement de dépôt du protore et des séries qui l'encadrent (du toit du FA au toit du FB) ; ii) du mode de formation des carbonates de Mn à 2,1 Ga et iii) de l'architecture et de la répartition des hautes teneurs en Mn du protore qui représente un gisement potentiel du futur.L’étude pétro-sédimentaire détaillée a permis de distinguer neuf unités (U1 à U9) au sein de la Formation FB organisées suivant un cycle rétrogradant jusqu’à U5 puis progradant jusqu’à U9. Ce découpage montre une évolution du milieu de dépôt depuis un domaine de shoreface contrôlé par des courants deltaïques (U1) évoluant vers des dépôts d’offshore restreint (U2). Ce bassin enregistre ensuite un système de chenaux-levées turbiditiques (U3) qui alimentent un réseau d'injectites reconnu sur l’ensemble du Pl. de Bangombé et qui traverse 150 m de série (U4 à U7) en affectant le protore et ainsi les teneurs en Mn. L'environnement de dépôt du protore (U5 et U6) marque l’isolement du bassin qui devient affamé et contrôlé par une sédimentation biochimique à l’origine du dépôt des carbonates de Mn. L'Unité 7 correspond à la réouverture des apports détritiques en domaine d'offshore supérieur puis en domaine de shoreface dominé par des dépôts de tempêtes et de chenaux sous-aquatiques deltaïques (U8), et enfin lagunaire (U9) dans lequel apparaissent les premiers métazoaires de l’histoire de la planète, suivant une séquence régressive.Une étude géochimique a permis de préciser les conditions de dépôt du protore qui se forme en milieu alcalin anoxique à sub-oxique. Dans ce milieu, nous montrons pour la première fois une précipitation directe des carbonates de Mn sous forme bactériomorphe induite par l'activité photosynthétique des cyanobactéries qui consomment le CO2/HCO3 et conduisent à une augmentation du pH favorable à la formation des carbonates de Mn. L'activité cyanobactérienne est conditionnée par l’absence de courants de fond qui augmentent la turbidité du milieu et stoppent cette dernière.Les corrélations diagraphiques et séquentielles permettent de préciser la répartition spatiale et temporelle du FB permettant ainsi de replacer le protore dans l’histoire tectono-sédimentaire du bassin. Une première phase syn-tectonique (U1 à U3) contrôle l’épaisseur et la mise en place de dépôts turbiditiques dans les parties subsidentes, de dépôts argileux sur les pentes et de dépôt de carbonates sur les hauts-fonds. La seconde phase post tectonique (U4 à U7) permet la mise en place de dépôts relativement isopaques, bien que le protore enregistre une subsidence plus importante au nord du Pl. de Bangombé. On observe ainsi, sur le Plateau de Bangombé, des teneurs en Mn qui augmentent vers le sud alors que l’épaisseur du protore augmente vers le NNE. Postérieurement au dépôt du FB, le protore est structuré par des failles qui le compartimentent en touches de piano limitant ainsi sa continuité sur le Plateau de Bangombé.
https://hal.archives-ouvertes.fr/tel-01621460

tel-01621460
https://hal.archives-ouvertes.fr/tel-01621460
https://hal.archives-ouvertes.fr/tel-01621460/document
https://hal.archives-ouvertes.fr/tel-01621460/file/these_Dubois2017-MnGabon.pdf

Éditeur(s) : HAL CCSD Elsevier
Résumé : High-precision Ni isotopic variations are reported for the metal phase of equilibrated and unequilibrated ordinary chondrites, carbonaceous chondrites, iron meteorites, mesosiderites, and pallasites. We also report new Zn and Cu isotopic data for some of these samples and combine them with literature Fe, Cu, and Zn isotope data to constrain the fractionation history of metals during nebular (vapor/solid) and planetary (metal/sulfide/silicate) phase changes. The observed variations of the Ni-62/Ni-58, Ni-61/Ni-58, and Ni-60/Ni-58 ratios vary linearly with mass difference and define isotope fractionation lines in common with terrestrial samples. This implies that Ni was derived from a single homogeneous reservoir. While no Ni-60 anomaly is detected within the analytical uncertainties, Ni isotopic fractionation up to 0.45 parts per thousand per mass-difference unit is observed. The isotope compositions of Ni and Zn in chondrites are positively correlated. We suggest that, in ordinary chondrites, exchange between solid phases, in particular metal and silicates, and vapor followed by mineral sorting during accretion are the main processes controlling these isotopic variations. The positive correlation between Ni and Zn isotope compositions contrasts with a negative correlation between Ni (and Zn) and Cu isotope compositions, which, when taken together, do not favor a simple kinetic interpretation. The observed transition element similarities between different groups of chondrites and iron meteorites are consistent with the genetic relationships inferred from oxygen isotopes (IIIA/pallasites and IVA/L chondrites). Copper is an exception, which we suggest may be related to separate processing of sulfides either in the vapor or during core formation. (C) 2007 Elsevier Ltd. All rights reserved.
ISSN: 0016-7037

hal-00408304
https://hal.archives-ouvertes.fr/hal-00408304
DOI : 10.1016/j.gca.2007.06.049

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
High-grade migmatitic and mylonitic gneisses from the Day Nui Con Voi massif in northern Vietnam record temperatures of 760-810 °C at pressures of 6-10 kbars. High temperature conditions have resulted in the development of major element diffusional profiles in garnet. Laser ablation ICP-MS analyses of trace elements indicate that REE and Hf closely followed Rayleigh-like fractionation trends but underwent significant post-crystallization modification. Light REE and to a lesser extent, HREE rim-to-rim zonation profiles show progressive flattening with the decreasing garnet size. Nd and Sm are completely homogenized in the crystals smaller than 1.5 mm, while Lu always preserves variable degrees of core-to-rim concentration gradient. The observed REE patterns are interpreted as resulting from the combination of protracted garnet growth of progressively smaller crystals and intracrystalline diffusion. This had profound influence on Sm-Nd geochronology and resulted in isochron ages ranging from 50 to 32 Ma. The youngest age was obtained for a sample, where all garnet crystals are smaller than 2 mm in which light REE profiles are completely or nearly completely homogenized. Thus, only the youngest age represents geologically meaningful event, and 31.7 ± 0.9 Ma age is interpreted as the best estimate of the resetting episode due to high temperature diffusional homogenization of light REE during early Oligocene metamorphism. Older Sm-Nd ages reflect mixed analyses of variably reset individual garnet crystals. Lu-Hf isotopic analyses of bulk garnet fractions, despite yielding high parent/daughter isotopic ratios appeared very scattered and did not allow defining isochron ages. Instead, apparent ages defined by whole rock and individual garnet fractions range from c. 80 to 160 Ma. Very old apparent ages are interpreted as being the consequence of intracrystalline Lu diffusion and preservation of the original Hf distribution, which leads to lower 176Lu/177Hf ratios, and thus steeper (older) isochrons. Back diffusion of Lu during commonly observed resorption played a subordinate role in modifying isotope systematics.
ISSN: 0009-2541

hal-00813949
https://hal.archives-ouvertes.fr/hal-00813949
DOI : 10.1016/j.chemgeo.2012.04.024

Éditeur(s) : HAL CCSD American Association of Petroleum Geologists
Résumé : In reservoir engineering, hydrodynamic properties can be estimated from downhole electrical data using heuristic models (e.g., Archie and Kozeny-Carman's equations) relating electrical conductivity to porosity and permeability. Although proven to be predictive for many sandstone reservoirs, the models mostly fail when applied to carbonate reservoirs that generally display extremely complex pore network structures. In this article, we investigate the control of the three-dimensional (3-D) geometry and morphology of the pore network on the electrical and flow properties, comparing core-scale laboratory measurements and 3-D x-ray microtomography image analysis of samples from a Miocene reefal carbonate platform located in Mallorca (Spain). The results show that micrometer- to centimeter-scale heterogeneities strongly influence the measured macroscopic physical parameters that are then used to evaluate the hydrodynamic properties of the rock, and therefore, existing models might not provide accurate descriptions because these heterogeneities occur at scales smaller than those of the integration volume of the borehole geophysical methods. However, associated with specific data processing, 3-D imagery techniques are a useful and probably unique mean to characterize the rock heterogeneity and, thus, the properties variability.
ISSN: 0149-1423

hal-00950066
https://hal.archives-ouvertes.fr/hal-00950066
DOI : 10.1306/05221312134

Éditeur(s) : Oxford university press
Résumé : The response of fish assemblages to changes in protection status is a major issue for both biodiversity conservation and fishery management. In New Caledonia, the Abore reef marine reserve harbours more than 500 fish species, and has been subjected to changes in protection status since 1988. The present study investigates the impact of these changes on a wide subset of species (213), based on underwater visual counts collected before the opening and after the closure to fishing of this marine protected area (MPA). We analysed the spatial and temporal variability in fish assemblage attributable to protection status, explicitly considering habitat. To understand the successive responses of fish assemblage to fishing and protection, the assessment models included four criteria de. ning species groups that partition the fish assemblage: trophic regime, adult size, mobility, and interest for fishing. We could therefore identify the negative impact of opening the MPA to fishing on piscivores and highly mobile species. Surprisingly, target species were not affected more than non-target species. Model results were used to identify species groups that respond to fishing and protection. These results utilize fisheries-related criteria to provide new insight into the response of fish assemblages to protection from the perspective of MPA monitoring.
ICES Journal of Marine Science (1054-3139) (Oxford university press), 2009 , Vol. 66 , N. 1 , P. 170-179

Droits : 2009 ICES/CIEM. Oxford Journals
http://archimer.ifremer.fr/doc/2009/publication-6130.pdf
DOI:10.1093/icesjms/fsn204
http://archimer.ifremer.fr/doc/00000/6130/

Éditeur(s) : HAL CCSD Integrated Ocean Drilling Program
Résumé : This contribution is a compilation of electron microprobe analyses of primary minerals in mafic and ultramafic oceanic crustal rocks from Atlantis Massif. The samples were recovered during Integrated Ocean Drilling Program Expedition 304/305, which was designed to investigate the formation and evolution of oceanic core complexes. The analyses were performed at five different institutions, and while common standard reference materials were not utilized at all institutions, internal standards and routine operational protocols were undertaken to assure analysis quality. More than 5000 analyses of plagioclase, pyroxene, olivine, and spinel are compiled here as a collaborative effort to provide mineral analyses to the expedition shipboard science party and other interested researchers.
ISSN: 1930-1014

hal-00464225
https://hal.archives-ouvertes.fr/hal-00464225
DOI : 10.2204/iodp.proc.304305.202.2009

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
The current design studies on sodium-cooled fast reactors (SFRs) are breaking with the past since they are guided by a new set of design criteria arising from the objectives of Generation IV reactors. The new safety requirements lead to designing reactors with breakeven breeding cores because in terms of reactivity control, they minimize the need to limit the consequences of an inadvertent control rod withdrawal event. Furthermore, as the reactivity control needs are low, a breakeven core enables the use of absorbing materials with reduced efficiency (natural boron, hafnium, etc.), which may be less costly than enriched boron. However, control rods designed with low absorbing materials may present the disadvantage of a nonnegligible loss of efficiency due to their consumption under irradn. This paper presents a methodol. to accurately calc. and to analyze the impact of this consumption on reactivity control.
ISSN: 0302-2927

hal-01088526
https://hal.archives-ouvertes.fr/hal-01088526
DOI : 10.13182/NSE13-59

Éditeur(s) : HAL CCSD
Résumé : Coral reefs are amongst the richest and more emblematic ecosystems of the world. These hotspots of biodiversity provide many services to Human societies, bringing leisure and economic added values. In many areas, especially developing countries, these ecosystems are submitted to both climate change (rise of sea temperature and level, acidification) and human coastal pressures (urbanisation, resources exploitation). In this context, an increasing number of Marine Protected Areas is settled on coral reefs environments in order to ensure their conservation and to mitigate local pressures. Hence, one of MPAs Managers' missions is to bring ecological and social data together to build integrated indicators of effectiveness. In Reunion Island, a MPA called the Marine reserve of La Réunion was settled in 2007 along a densely urbanised and populated fringing reef coast. In order to better evaluate its MPA effectiveness, the manager requires the integration of social stakes to the management plan. A uses monitoring protocol was developed in this purpose using an ultra light aircraft and a camera. Data on 15 different recreational and non-recreational uses were acquired between 2010 and 2013, flying 48 times a year, and entered into a Geographic Information System. A huge resulting database allowed the building of an initial knowledge of the spatio-temporal distribution of uses within the Reserve. It also enabled the analysis of the uses' evolution regarding various factors of variations (amenities, facilities, shark attacks, tourism, etc.). Finally, we assessed the contribution to management efficiency using social indicators (governance, pressure indicators), and to interdisciplinary research in bringing ecologic and uses data together. This thesis brings a brand new information about coastal human activity and spatio-temporal dynamics of direct pressures on reef. This tool, designed to be reproducible and cost-optimized, enables the production of a set of indicators. Its integration to the management plan exclusively depends on the strategic choices of the manager.
Les récifs coralliens figurent parmi les biomes côtiers les plus emblématiques de la planète. Ces points chauds de la biodiversité mondiale sont convoités par les sociétés humaines pour leurs qualités paysagères et leur plus-value économique. Exposés au même titre que de nombreux écosystèmes côtiers aux changements climatiques (élévation de la température, acidification des océans), ils sont de toutes parts soumis à une anthropisation littorale mal maitrisée (urbanisation, surexploitation des ressources). Dans ce contexte, de plus en plus d' Aires Marines Protégées (AMP) s'établissent sur des écosystèmes anthropisés, les amenant à intégrer l'Homme au coeur de la gestion. À La Réunion où l'urbanisation littorale est dense et où le paysage des usages littoraux ne cesse de s’étoffer, une Réserve Naturelle Marine (RNMR) a été établie en 2007 sur un récif frangeant. L’évaluation de l’efficacité de cette AMP par son gestionnaire doit se faire par le biais d'un ensemble d'indicateurs écologiques et socio-économiques. C’est en vue d’apporter des connaissances sur la fréquentation et les usages pratiqués au sein de la RNMR que cette thèse a été initiée. Elaboré sur la base d'un suivi en ULM, un protocole a été reproduit chaque année entre 2010 et 2013 et a permis la constitution d'une base de données spatialisée, dont l'exploitation a produit trois types de résultats: i) une connaissance initiale de la répartition spatio-temporelle des usages au sein de la RNMR; ii) une compréhension de l'évolution des dynamiques spatio-temporelles à la lumière des facteurs de variations identifiés (aménagements, aménités, crise requin, tourisme, etc.), et iii) une contribution à la gestion par le développement d'indicateurs sociaux (gouvernance, pressions), et à la recherche interdisciplinaire par une confrontation des données de fréquentation et des données écologiques du milieu. La réflexion menée dans le cadre de cette thèse apporte un éclairage nouveau sur les usages et la fréquentation des littoraux coralliens à La Réunion, et leur traduction en termes de pression anthropique directe. Pensé pour être reproductible et optimisé en termes de coût, cet outil permet la production d’un ensemble d’indicateurs dont l’intégration au plan de gestion dépend exclusivement des choix stratégiques du gestionnaire.
https://tel.archives-ouvertes.fr/tel-01308703

Droits : http://creativecommons.org/licenses/by-nc-sa/
tel-01308703
https://tel.archives-ouvertes.fr/tel-01308703
https://tel.archives-ouvertes.fr/tel-01308703/document
https://tel.archives-ouvertes.fr/tel-01308703/file/Th%C3%A8se_Lemahieu.pdf

Éditeur(s) : HAL CCSD Royal Society, The
Résumé : International audience
Endemic species are frequently assumed to have lower genetic diversity than species with large distributions, even if closely related. This assumption is based on research from the terrestrial environment and theoretical evolutionary modelling. We test this assumption in the marine environment by analysing the mitochondrial genetic diversity of 33 coral reef fish species from five families sampled from Pacific Ocean archipelagos. Surprisingly, haplotype and nucleotide diversity did not differ significantly between endemic and widespread species. The probable explanation is that the effective population size of some widespread fishes locally is similar to that of many of the endemics. Connectivity across parts of the distribution of the widespread species is probably low, so widespread species can operate like endemics at the extreme or isolated parts of their range. Mitochondrial genetic diversity of many endemic reef fish species may not either limit range size or be a source of vulnerability.
ISSN: 0962-8452

hal-01333327
https://hal-univ-perp.archives-ouvertes.fr/hal-01333327
DOI : 10.1098/rspb.2014.1068