Éditeur(s) : HAL CCSD
Résumé : The Tyrrhenian Sea is usually interpreted to be a Neogene back-arc basin that opened by continental rifting and oceanic spreading caused by the eastward migration of the Apennine subduction system from Tortonian to Pliocene times. Rifting of the Tyrrhenian Sea started first along the Eastern Sardinian margin during the Tortonian-Messinian times. The " METYSS " project aims at better constraining the relations between crustal tectonics, salt tectonics and sedimentation from Messinian times to present-day. The " METYSS 1 " cruise (2009, R/V "Téthys II"-INSU) allowed us to obtain about 1200 km of high-resolution seismic reflection profiles along the SE Corsican margin, and along the upper and middle parts of the Eastern Sardinian margin, Western Tyrrhenian. This new dataset clearly illustrates that this area has been highly dissected during the rifting stage by N-S trending normal faults delineating ridges and basins, as previously described. The Messinian seismic markers (UU and MU) locally display fan-shaped stratal geometries, but the mechanism responsible for such geometries, i.e., salt tectonics or rifting, has yet to be carefully deciphered. We also mapped the spatial distribution of the mobile salt (MU). The highly variable thickness of the confined salt basins may be related to the initial pre-Messinian basin geometry or to the fact that sediment deposition was syn-rift. Southeastward, salt tectonics appears highly vigorous. More surprisingly, our data demonstrate that some of the major faults have been significantly reactivated during the post-rift period, up to late Quaternary time. Such recent fault activity has been recorded by bathymetric scarps and associated footwall debris flows. Moreover, some of this post-rift deformation can be evidenced within the Plio-Quaternary sequence by a regional unconformity. The post-Miocene deformation style varies greatly between different areas of the margin, and can also be strongly influenced by the presence or absence of mobile Messinian evaporites (MU).
13ème Congrès Français de Sédimentologie
Dijon, France

hal-00657310
https://hal-brgm.archives-ouvertes.fr/hal-00657310

Éditeur(s) : Elsevier
Résumé : Marine fish larvae undergo major morphological and cellular changes during the first month of life. The ontogeny of the gastrointestinal tract combines these two aspects of the larval development and is very interesting in that the timing of functional changes appears genetically hard-wired. The goal of this paper is to give an overview of the gastrointestinal development process in marine fish larvae, with particular attention to three species: sea bass; red drum; and sole, since the description of gut maturation in fish larvae was initiated during the last decade with these species. During the early stages, marine fish larvae exhibit particular digestive features. Concerning the exocrine pancreas, amylase expression decreases with age from the third week post-hatching in sea bass and red drum (approximately 400 degree days), whereas expression of other enzymes (trypsin, lipase, phospholipase A2...) increases until the end of the larva period. Moreover, secretory function of the exocrine pancreas progressively develops and becomes efficient after the third week of life. Concerning the intestine, enzymes of the enterocyte cytosol (in particular peptidase) have higher activity in young larvae than in older. Approximately in the fourth week of post-hatching development in sea bass, red drum and sole larvae, the cytosolic activities dramatically decline concurrently with a sharp increase in membranous enzyme activities of the brush border, such as alkaline phosphatase, aminopeptidase N, maltase... This process characterises the normal maturation of enterocytes in developing fish larvae and also in other vertebrates' species. The establishment of an efficient brush border membrane digestion represents the adult mode of digestion of enterocytes. This paper also describes the role of diet on the development of the gastrointestinal tract. Indeed, the maturational process of digestive enzyme can be enhanced, stopped, or delayed depending on the composition of the diet.
Comparative Biochemistry and Physiology Part C: Toxicology & Pharmacology (1532-0456) (Elsevier), 2001-12 , Vol. 130 , N. 4 , P. 477-487

Droits : 2001 Elsevier Science Inc. All rights reserved
http://archimer.ifremer.fr/doc/2001/publication-650.pdf
DOI:10.1016/S1532-0456(01)00274-5
http://archimer.ifremer.fr/doc/00000/650/

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

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

Éditeur(s) : HAL CCSD
Résumé : International audience
The core of South East Asia is composed of a mosaic of continental blocks, among which the Indochina and theSouth China blocks (present day northern Vietnam), amalgamated during the Permian and/or the Triassic. LatePermian to Late Triassic geodynamic evolution of these two blocks remains controversial. The main discussionpoints concern the existence and the closure of an oceanic domain separating the Indochina and the South Chinablocks during this period. Especially, the polarity and the timing of the subduction zone that led to the collisionbetween the blocks as well as the present location of the suture delimiting them are a matter of debate. Despite thevaluable information they can provide, the sedimentary basins from northern Vietnam have been neglected in theprevious studies dealing with the geodynamic evolution of South East Asia.To determine the geodynamic evolution of the area, the basins of Sam Nua and Song Da, presently locatedin North Vietnam, have been investigated using a combined approach involving sedimentology, geochronology(U-Pb/zircon) and geochemistry (whole-rock major and trace elements composition of both volcanic and volcaniclasticrocks). The palaeoenvironment evolution, the main unconformities, their age and the tectonic affinitiesof the interbedded volcanic and volcaniclastics series have been characterized for these two basins. Our resultsdemonstrate (i) that the Song Da Basin exhibits a palaeogeographic affinity with the South China block, (ii) theoccurrence of extensive calk-alkaline volcanism and associated volcaniclastic deposits in the Sam Nua Basin,related to the existence of an active magmatic arc during the Early and the lower Middle Triassic, (iii) a Southdipping (present day coordinate) oceanic lithosphere beneath the Indochina block, deduced from the location ofthe magmatic arc south of the potential suture zones, (iv) that an angular unconformity postdates the lower MiddleTriassic volcaniclastic deposits in the Sam Nua basin. This unconformity, crosscutting the subduction relateddeposits, is interpreted as the result of the collision between the Indochina and the South China blocks.
European Geoscience Union General Assembly 2015
Vienne, Austria

insu-01137675
https://hal-insu.archives-ouvertes.fr/insu-01137675

Éditeur(s) : HAL CCSD Taylor & Francis
Résumé : International audience
The functional organization of the circadian system and the location of the main circadian oscillators vary through phylogeny. Present study investigates by in situ hybridization the anatomical location of the clock gene gPer1b in forebrain and midbrain, pituitary, and in two peripheral locations, the anterior intestine and liver, in a teleost fish, the goldfish (Carassius auratus). Moreover, the daily expression profiles of this gene were also studied by quantitative Real Time-PCR. Goldfish were maintained under a 12L–12D photoperiod and fed daily at 2 h after lights were switched on. A wide distribution of gPer1b mRNA in goldfish brain and pituitary was found in telencephalon, some hypothalamic nuclei (including the homologous to mammalian SCN), habenular nucleus, optic tectum, cerebellum and torus longitudinalis. Moreover, gPer1b expression was observed, for the first time in teleosts, in the pituitary, liver and anterior intestine. Day/night differences in gper1b mRNA abundance were found by in situ hybridization, with higher signal at nighttime that correlates with the results obtained by RT-PCR, where a rhythmic gPer1b expression was found in all tissues with acrophases at the end of the night. Amplitudes of gper1b rhythms vary among tissues, being higher in liver and intestine than in the brain, maybe because different cues entrain clocks in these locations. These results support the existence of functional clocks in many central and peripheral locations in goldfish coordinated, ticking at the same time
ISSN: 0742-0528

hal-01197353
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01197353
DOI : 10.3109/07420528.2015.1049615
PUBMED : 26171989

Éditeur(s) : HAL CCSD Consejo Superior de Investigaciones Científicas
Résumé : International audience
The temporal variation in carbon and nitrogen isotopic compositions (noted as δ 13 C and δ 15 N) was investigated in the convict surgeonfish (Acanthurus triostegus) at Moorea (French Polynesia). Over a period of 24 days, juveniles were reared in aquaria and subjected to two different feeding treatments: granules or algae. The dynamics of δ 13 C and δ 15 N in two muscles (the adductor mandibulae complex and the epaxial musculature) having different functions were compared. At the end of experiments, a steady-state isotopic system in each muscle tissue was not reached. Especially for the algal treatment, we found different patterns of variation in isotopic compositions over time between the two muscles. The turnovers of δ 13 C showed opposite trends for each muscle but differences are mitigated by starvation and by the metamorphosis. Our study highlighted that the metabolism of coral reef fish may be subjected to catabolism or anabolism of non-protein precursors at settlement, inducing variation in isotopic compositions that are not linked to diet change. Comparación de la dinámica de variación isotópica en dos músculos de un pez de arrecife de coral durante la fase de asentamiento Resumen: La variación temporal en la composiciones isotópicas del carbono y nitrógeno (δ 13 C y δ 15 N) fue investigada en el pez cirujano Acanthurus triostegus en Moorea (Polinesia Francesa). Durante un período de 24 días, peces juveniles se mantuvieron en acuarios y se sometieron a dos tratamientos de alimentación: gránulos o algas. Se compararon las dinámicas de cambio δ 13 C y δ 15 N en dos músculos con diferentes funciones (complejo aductor mandibular y musculatura epiaxial). Al final de los experimentos, no se alcanzó un sistema isotópico de estado estacionario en ningún tejido. Especialmente para el tratamiento de algas, encontramos distintos patrones de variación en composiciones isotópicas en el tiempo entre los dos músculos. Las variaciones en δ 13 C mostraron tendencias opuestas para cada músculo, pero las diferencias fueron mitigadas por la inanición y la metamorfosis. Nuestro estudio destaca que el metabolismo de los peces de arrecife puede ser sometido a catabolismo o anabolismo por los precursores no proteicos durante el asentamiento, induciendo variación en las composi-ciones isotópicas que no están vinculados al cambio de dieta.
ISSN: 0214-8358

Droits : http://creativecommons.org/licenses/by-nc/
hal-01212253
https://hal-univ-perp.archives-ouvertes.fr/hal-01212253
https://hal-univ-perp.archives-ouvertes.fr/hal-01212253/document
https://hal-univ-perp.archives-ouvertes.fr/hal-01212253/file/1598-3145-1-PB.pdf
DOI : 10.3989/scimar.04225.31A

Éditeur(s) : Elsevier Science Bv
Résumé : In this study, three microdiets were tested on weaning of Florida pompano larvae: Otohime, Gemma and a reference diet LR803. The experimental system was stocked with 11-day-old larvae, which were co-fed micro-diets and live food from 11 dph to 17 dph then micro-diets only until 28 dph. Survival from 11 dph to 28 dph was similar for all treatments, with an average of 33%. At the end of the trial, the Gemma larvae were significantly longer and heavier than larvae fed the other diets. Significant differences were observed in fatty acid composition of the diets and larvae between treatments. The Gemma larvae incorporated the lowest amount of eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA) and arachidonic acid (ARA). However, they had the highest DHA/EPA and ARA/EPA ratios, which is in agreement with the concept that the proportions of polyunsaturated fatty acids could be of greater importance than their absolute amount. Results from the enzyme analysis suggest that fishmeal is suitable as the main protein source for Florida pompano larvae compared to krill meal. This study gives new insights on Florida pompano early nutritional requirements and demonstrated the full functionality of the pancreas at 16 days post hatch, opening possibilities of an earlier weaning time.
Aquaculture (0044-8486) (Elsevier Science Bv), 2014-02 , Vol. 422 , P. 268-276

Droits : 2013 Elsevier B.V. All rights reserved
http://archimer.ifremer.fr/doc/00169/28067/26282.pdf
DOI:10.1016/j.aquaculture.2013.12.006
http://archimer.ifremer.fr/doc/00169/28067/

Éditeur(s) : Institut national agronomique Paris Grignon
Résumé : The flat oyster Ostrea edulis L. is the indigenous oyster of the Atlantic as well as the Mediterranean coasts of Europe. Its commercial exploitation dates back to Antiquity but its breeding is now threatened by two parasitic protozoa, among which Bonamia ostreae. Various aspects of the genetics of this species' natural and farmed populations have been studied with the aid of microsatellite markers. At first, the implementation and the screening of two partial genomic libraries made it possible to identify 28 new microsatellite loci. Analysis of the segregation of 12 of these loci and of two enzymatic loci shows that most microsatellite loci are transmitted in a Mendelian way, but some loci have significant segregation distortions. Moreover, seven linkage groups, of which four contain at least two markers, were identified in Ostrea edulis. The genetic variability of three populations selected for one or two generations for resistance to Bonamia ostreae was analysed with the aid of 5 microsatellite loci. In spite of the absence of genealogical data, we have shown that these selected populations were descended from a very low number of founding genitors (from 3 to 15 depending on the population) and for two populations, we were able to reconstruct the genealogy and the relationships between the individuals were identified. These selected populations have, in addition to a very low genetic variability, real and at times high levels of consanguinity. These results have a significant implication for the continuation of the selection programme (consanguinity management, augmentation of genetic variability by introducing wild genitors). The geographical structuring of the genetic variability of natural populations of Ostrea edulis has been analysed with the aid of 5 microsatellite loci on a sampling covering almost the entire distribution area of the species (from Norway to the Adriatic Sea). The results are consistent with those published in the literature and using enzymatic markers. The populations show a low level of differentiation that could correspond to a model of isolation by distance. The Atlantic populations, which have a reduced polymorphism, could be descended from post-glacial recolonisation from Mediterranean populations that had survived the glaciations of the Quaternary Period. The current distribution of flat oyster populations is surely also subject to anthropogenic activities. Finally, the genetic bases of the heterozygosis-growth correlation were studied in a natural population with the aid of enzymatic and microsatellite markers. Although leads favouring the direct contribution of enzymatic loci have been found, biases in the sampling design make it impossible to come to a formal conclusion. However, this study has made it possible to show that the capture of individuals over a short period (around ten days) leads to a sampling of a population descended from a very low number of founding genitors, in contradiction with the generally accepted idea that marine bivalve populations are large panmictic populations with significant, efficient numbers. These results confirm in a natural population the observations of a significant reduction of efficient sizes in hatchery populations.
L'huître plate Ostrea edulis L. est l'huître indigène des côtes européennes aussi bien atlantiques que méditerranéennes. Son exploitation commerciale remonte à l'Antiquité mais son élevage est aujourd'hui menacé par deux protozoaires parasites dont Bonamia ostreae. Différents aspects de la génétique des populations naturelles et cultivées de cette espèce ont été étudiés à l'aide de marqueurs microsatellites. Dans un premier temps, la réalisation et le criblage de deux banques génomiques partielles ont permis l'identification de 28 nouveaux locus microsatellites. L'analyse de la ségrégation de 12 de ces locus et de deux locus enzymatiques montre que la plupart des locus microsatellites sont transmis de façon mendélienne, mais certains locus présentent des distorsions de ségrégation importantes. Par ailleurs, sept groupes de liaison dont quatre contiennent au moins deux marqueurs ont été identifiés chez Ostrea edulis. La variabilité génétique de trois populations sélectionnées depuis une ou deux générations pour une résistance à Bonamia ostreae a été analysée à l'aide de 5 locus microsatellites. Malgré l'absence de données généalogiques, nous avons montré que ces populations sélectionnées étaient issues d'un très faible nombre de géniteurs fondateurs (de 3 à 15 selon les populations) et pour deux populations, la généalogie a pu être reconstituée et les liens de parenté entre les individus ont été identifiés. Ces populations sélectionnées présentent, outre une très faible variabilité génétique, des niveaux de consanguinité réels et parfois élevés. Ces résultats ont une implication importante pour la continuation du programme de sélection (gestion de la consanguinité, augmentation de la variabilité génétique par introduction de géniteurs sauvages). La structuration géographique de la variabilité génétique des populations naturelles d'Ostrea edulis a été analysée à l'aide de 5 locus microsatellites sur un échantillonnage couvrant presque toute l'aire de répartition de l'espèce (de la Norvège à la Mer Adriatique). Les résultats sont cohérents avec ceux publiés dans la littérature et utilisant des marqueurs enzymatiques. Les populations montrent un niveau de différenciation faible qui pourrait correspondre à un modèle d'isolement par la distance. Les populations atlantiques, qui présentent un polymorphisme réduit, pourraient être issues de recolonisation post-glaciaire à partir de populations méditerranéennes ayant survécu aux glaciations du Quaternaire. La répartition actuelle des populations d'huître plate est certainement aussi soumise aux actions anthropiques. Enfin, les bases génétiques de la corrélation hétérozygotie-croissance ont été étudiées dans une population naturelle à l'aide de marqueurs enzymatiques et microsatellites. Bien que des pistes en faveur de la contribution directe des locus enzymatiques aient été trouvées, des biais dans le dispositif expérimental ne permettent pas de conclure de façon formelle. Cependant, cette étude a permis de montrer que le captage d'individus sur une faible période (une dizaine de jours) conduit à l'échantillonnage d'une population issue d'un nombre très réduit de géniteurs fondateurs, en contradiction avec l'idée reçue que les populations de bivalves marins sont de larges populations panmictiques à effectif efficace important. Ces résultats confirment dans une population naturelle les observations de réduction importante des tailles efficaces dans des populations d'écloserie.

Droits : info:eu-repo/semantics/openAccess
http://archimer.ifremer.fr/doc/1998/these-1919.pdf
http://archimer.ifremer.fr/doc/00000/1919/

Éditeur(s) : Ecole Nationale Supérieure Agronomique de Rennes (ENSAR)
Résumé : Artificial Fish Aggregating Devices (FADs) are known to concentrate tropical tunas. This aggregative behaviour drastically increases the vulnerability of these species to fishing. Alternatively, FADs can be used as oceanic observatories to study the aggregative behaviour of large pelagic fish. We conducted sea surveys in Martinique (Lesser Antilles) to i) establish a typology of the pelagic fish aggregations found around moored FADs ii) study their relations with their biotic and abiotic environment and the local fishery. The mean biomass of large pelagic fish aggregations was also estimated to provide scientific inputs to achieve a sustainable management of the moored FAD fishery. The first part presents the background of the study. We introduce the regional pelagic ecosystem, the aggregative behaviour of pelagic fish around FADs and the Martinican moored FAD fishery. The second part begins with a presentation of the conceptual framework of the study: the hierarchy theory. Observation scales and survey methodology are therefore described. Repeated echosounder surveys run in a star pattern were conducted around 2 moored FADs, in combination with underwater video observations, classical fishing experiments and CTD profiles. In the third part, the elements of the [moored FAD ¿ pelagic fish - environment - fishing] system and their interactions are numerically characterised in the vertical plane. The main type of pelagic fish aggregation was a large aggregation distributed in sub-surface (40-100 m) within a radius of 400 m of the FAD. This aggregation was mostly made of 60 cm FL blackfin tunas (Thunnus atlanticus). It appeared at sunrise and mostly spread away in the late afternoon. It was observed during all daytime surveys. The average density and the vertical structure of the micronektonic sound scattering layers (SSLs) were assessed locally around a FAD for 48h cycles. These SSLs descriptors showed positive correlation with the size and the abundance of the sub-surface tuna aggregation. Whereas this aggregation accounted for about 95% of the total biomass aggregated around a moored FAD, it was nearly unexploited by the local commercial fishermen. The fourth part focuses on the sub-surface tuna aggregation. A high variability of the spatial distribution of the aggregation was evidenced in the horizontal plane at daily, day to day and monthly temporal scales. These variations were related to fluctuations of the global abundance of the aggregation. The daytime average density of sub-surface tuna was modelled as a function of the distance to FAD, within an advection-diffusion framework. Based on these results, a universal kriging model was designed to assess the mean maximum daily biomass of the sub-surface tuna aggregation. This mean biomass estimate yielded 11 tons with an estimation error of 26%. To conclude, we present a hierarchical organization in space and time of a sub-surface tuna population distributed within a network of moored FADs, from micro to meso-scale. We suggest that the spatial distribution of tunas can be explained from fine to coarse-scales by behavioural processes (self-organization, feeding, aggregative behaviour) whereas their spatial distribution is mainly forced by environmental processes at broader scales.
L'utilisation de Dispositifs de Concentration de Poissons permet de provoquer la formation de larges agrégations de thonidés autour de dispositifs artificiels, ce qui augmente considérablement la vulnérabilité de ces ressources vis-à-vis de l'exploitation halieutique. Les DCP peuvent également être utilisés en tant qu'observatoires océaniques, afin d'étudier le comportement agrégatif du macronecton pélagique. Nous avons ainsi réalisé des observations autour de DCP ancrés en Martinique, afin de définir une typologie des agrégations de macronecton et de étudier leurs relations avec leur environnement biotique, abiotique et l'exploitation halieutique locale. Nous avons ensuite estimé la biomasse moyenne de macronecton agrégé autour d'un DCP ancré, afin de fournir des éléments scientifiques nécessaires à une gestion durable de ces ressources. La première partie présente le contexte de l'étude i.e. l'écosystème pélagique régional, le phénomène d'agrégation du macronecton autour des DCP et la pêche associée aux DCP ancrés en Martinique. La deuxième partie introduit la théorie de la hiérarchie qui a fourni le cadre conceptuel de l'étude et présente les échelles et méthodes d'observation. Le principal outil d'observation est un échosondeur scientifique, mis en oeuvre le long de parcours en étoile autour du DCP. Les prospections acoustiques ont été combinées à des observations vidéo sous marines, des pêches expérimentales et un suivi in-situ de l'environnement abiotique. La troisième partie présente une typologie des éléments constituant le système [DCP ancré - macronecton - environnement - pêche] dans le plan vertical et précise leurs interactions. Le type d'agrégation de macronecton dominant est une grande agrégation composée d'une majorité de thons noirs (Thunnus atlanticus) de taille moyenne (60 cm) distribuée en sub-surface (40-100 m), dans un rayon de 300 m autour de la tête des DCP. Cette agrégation se forme au lever du soleil et se disperse presque totalement dans l'après midi. Elle a été observée de jour lors de toutes les campagnes. Une corrélation positive entre la densité et la structure moyenne des couches micronectoniques diurnes évaluée localement autour du DCP au cours de 48 h et les dimensions et l'énergie acoustique de l'agrégation de thons de subs-surface a été mise en évidence. Malgré le fait que cette agrégation représente en moyenne 95 % de l'énergie acoustique du macronecton autour des DCP, elle est presque inexploitée par les pêcheurs artisans locaux. La quatrième partie met en évidence les fortes variations conjointes de la distribution spatiale dans le plan horizontal de la densité de l'agrégation de thons de sub-surface et de son abondance globale. Ces variations ont été observées au cours du cycle nycthéméral et aux échelles inter-journalières et mensuelles. La distribution spatiale moyenne de la densité diurne de l'agrégation en fonction de la distance au centre de gravité de l'agrégation est cependant très stable et peut être modélisée au moyen d'une équation d'advection-diffusion. Un modèle de krigeage universel, utilisant les résultats du modèle d'advection-diffusion, a permis d'évaluer la biomasse maximale journalière moyenne de l'agrégation de thons de sub-surface à une dizaine de tonnes, avec un coefficient de variation d'estimation de 26%. Nous proposons une représentation hiérarchique synthétique de la distribution spatiale d'une sous-population de thons dans un réseau de DCP ancrés de la micro à la méso-échelle. Nous suggérons que la distribution spatiale des thons est déterminée principalement à l'échelle fine (100m-1km) et à l'échelle grossière (1-10 km) par des processus comportementaux (auto-organisation, agrégation, nutrition) et par des processus environnementaux à échelle plus large.

Droits : info:eu-repo/semantics/openAccess
http://archimer.ifremer.fr/doc/2006/these-1735.pdf
http://archimer.ifremer.fr/doc/2006/sup-1735.pdf
http://archimer.ifremer.fr/doc/00000/1735/

Éditeur(s) : Blackwell science
Résumé : Peneid shrimp are commonly reared in clear-water aquaria or tanks for short-term studies of 4-6 weeks during controlled experiments, such as nutrition studies to estimate dietary nutrient requirements. Recently, in line with the genetic program at Centre Oceanologique du Pacifique (COP), experimental clear-water facilities were tested for the first time over a longer rearing period. Environmental conditions used to maintain animal growth in clear-water system using a well-balanced diet were defined. After 100 days, shrimp growth rates tended to decrease and only by adjusting the diet could shrimp complete their life cycle and reach maturation size of around 40 g. This paper presents information on stocking density, diet quality and husbandry linked to reproduction that must be considered to successfully rear animals from PL's to breeder size in clear water. By following these protocols a minimum amount of breeders can be used to meet production goals. Moreover, by isolating a small group of individuals, genetic diversity can be preserved, thereby allowing specific crosses for selective breeding purposes. Length of trials, amount of feed, composition of feed, growth performances and maturation success are reported and should encourage further studies to optimize rearing conditions in clear-water rearing.
Aquaculture Research (1355-557X) (Blackwell science), 2004-11 , Vol. 35 , N. 13 , P. 1244-1252

Droits : 2004 Blackwell Synergy
http://archimer.ifremer.fr/doc/2004/publication-619.pdf
DOI:10.1111/j.1365-2109.2004.01145.x
http://archimer.ifremer.fr/doc/00000/619/

Éditeur(s) : HAL CCSD Oxford University Press (OUP)
Résumé : International audience
Ocean loading effects cause 3-D displacements large enough to affect space geodesy measurements either at the subdiurnal periods or at longer time scales by the means of spurious signals. GPS measurements, in turn, could provide local improvements of the models in coastal areas if their ability to precisely monitor such rapid displacements is assessed. In this paper, we use 105 days of continuous GPS measurements collected in 2004 in the French Brittany and Cotentin region to investigate: (1) the precision achieved by the GPS analysis on measuring 3-D subdiurnal displacements and amplitude and phase of the tidal constituents, (2) the quality of the most recent ocean tide model FES2004 in such a complex coastal context. Indeed, in this area, tide amplitudes are among the largest in the world (up to 16 cm of loading displacements on the vertical component) and are believed to show strong shallow-water tides. From a state of the art GPS analysis using the scientific GAMIT software over 2-h sessions, we test two independent strategies for the realization of the reference frame. The position time series are then compared with the displacements predicted by the FES2004 model applied on an elastic Earth model. The two sets of results are consistent with each other at the same level of agreement than with the predicted displacements, namely 3–5 mm on the horizontal components, 10 mm on the vertical. This assesses the capability of this technique for measuring 3-D ocean tide loading deformation. We validate the FES2004 model in the Brittany area, even though it slightly (2–7 mm) underestimates the three components amplitudes. With a harmonic analysis of the observed position time series, we obtain nevertheless an agreement at a submillimetre level for the M2, N2, O1, Q1 tidal constituents and at a millimetre level for the K1 and S2 tidal constituents. Moreover, we can extract a significant M4 load signal at the 95 per cent confidence level from the GPS time series at the stations located in the Mont St Michel area. The detection of other shallow-water constituents would be helpful to understand the amplitude deficit between the FES2004 predicted and GPS observed displacements.
ISSN: 0956-540X

insu-00335909
https://hal-insu.archives-ouvertes.fr/insu-00335909
https://hal-insu.archives-ouvertes.fr/insu-00335909/document
https://hal-insu.archives-ouvertes.fr/insu-00335909/file/Vergnolle_GJI_08_revised.pdf
DOI : 10.1111/j.1365-246X.2008.03734.x

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
BACKGROUND: Mutations in the telomerase complex (TERT and TR) are associated with pulmonary fibrosis and frequent hematologic manifestations. The aim of this study was to characterize the prognosis of lung transplantation in patients with TERT or TR mutations. METHODS: Patients with documented TERT or TR mutations who received a lung transplant between 2007 and 2013 in France were identified via an exhaustive search of the lung transplantation network, one expert genetic laboratory, and the clinical research network on rare pulmonary diseases. RESULTS: There were 9 patients (7 men) with TERT (n = 6) or TR (n = 3) mutations who received a single (n = 8) or a double (n = 1) lung transplant for pulmonary fibrosis. Median age was 50 years (range, 35-61 years) at diagnosis and 52 years (range, 37-62 years) at the time of lung transplantation. Thrombocytopenia was present in 7 patients before lung transplantation. After lung transplantation, 6 patients developed myelodysplasia and/or bone marrow failure, directly contributing to death in 4 cases. Anemia was observed in 9 patients, and neutropenia was observed in 3 patients. The median survival after lung transplantation was 214 days (range, 59-1,709 days). CONCLUSIONS: Patients with mutations of the telomerase complex are at high risk of severe hematologic complications after lung transplantation, in particular, bone marrow failure. Specific recommendations should be developed for appropriate guidance regarding hematologic risk assessment before transplantation and management of the post-transplantation immunosuppressive regimen.
ISSN: 1053-2498

hal-01146848
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01146848
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01146848/document
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01146848/file/Severe%20hematological%20complications%20after%20lung%20transplantation_accepted.pdf
DOI : 10.1016/j.healun.2014.11.010

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
Deformation of the continental lithosphere is traditionally modeled assuming that heat production in the subcontinental lithospheric mantle is negligible. Although this may be appropriate for highly depleted Archean lithosphere, studies of mantle xenoliths and lithospheric-derived mafic rocks suggest that heat productions of up to 0.4 ;μW/m3 may be attained in the mantle of Phanerozoic and Neoproterozoic regions due to modal metasomatism. To investigate the effect of a local enrichment in heat-producing elements within the lithospheric mantle on the continental deformation, we performed a series of 2D thermo-mechanical models simulating the deformation of a lithospheric plate 1000 km long, which contains in its central part a 200 km wide and 20 km-thick mantle layer with a heat production of 0.05;–0.25 ;μW/m3 between 40 and 80 km depth, leading to a local enhancement of the surface heat flow by 1;–5 mW/m2. Compression models show that a 20 km-thick layer with a heat production as low as 0.05 ;μW/m3 within the shallow lithospheric mantle leads to strain localization in both the enriched mantle and the overlying crust. Strain localization depends exponentially on the temperature increase in the lithosphere section, which is controlled by the volume of metasomatized mantle and the intensity of the metasomatic enrichment in heat-producing elements. A heat production of 0.25 μW/m3 between 60 and 80 km depth results, for instance, in strains within and above the metasomatized mantle 5 times higher than in the surrounding lithosphere. Strain localization also depends on the location of the heat-producing domain and on the plate rheological structure; deeper heat-producing domains and weaker plates leading to stronger localization. These results provide an explanation for strain localization in intraplate environments, leading to the formation of orogenic belts situated hundreds to thousands of kilometers away from known plate boundaries, as observed in the Neoproterozoic belts of Gondwana and in the present-day deformation of the Asian plate.
ISSN: 0012-821X

hal-00411386
https://hal.archives-ouvertes.fr/hal-00411386
DOI : 10.1016/j.epsl.2008.07.040

Éditeur(s) : HAL CCSD
Résumé : International audience
This study assessed the usefulness of UV spectrophotometry for the monitoring of a yeast-based deoxygenation process proposed for ships' ballast water treatment to prevent the transfer of aquatic invasive species. Ten-day laboratory experiments using three treatment concentrations and different water types were conducted and resulted in complete oxygen depletion of treated waters. The treatment performance and quality of treated waters were determined by measuring the UV-visible absorbance spectra of water samples taken over time. Samples were also used for laboratory analysis of water quality properties. The UV absorbance spectra values were strongly correlated (r = 0.96) to yeast cell density in treated waters. The second-order derivative (D (2)) of the spectra varied greatly over time, and the spectrum profiles could be divided into two groups corresponding to the oxygenated and anoxic phases of the treatment. The D (2) value at 215 nm was strongly correlated (r = 0.94) to ammonia levels, which increased over time. The D (2) value at 225 nm was strongly correlated (r  extgreater 0.97) to DO concentration. Our results showed that UV spectrophotometry may provide a rapid assessment of the behavior and performance of the yeast bioreactor over time by quantifying (1) the density of yeast cells, (2) the time at which anoxic conditions were reached, and (3) a water quality index of the treated water related to the production of ammonia. We conclude that the rapidity of the technique confers a solid advantage over standard methods used for water quality analysis in laboratory and would permit the direct monitoring of the treatment performance on-board ships
Environmental Monitoring and Assessment

hal-01286253
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01286253
DOI : 10.1007/s10661-016-5209-3
PUBMED : 26944435

Éditeur(s) : Elsevier
Résumé : Sea cruises were conducted for 57 days over 16 months to characterise pelagic fish aggregations around 2 moored fish aggregating devices (FADs) in Martinique (Lesser Antilles). Echosounder surveys run in a star pattern were used in conjunction with obliquely beamed sonar observations. An echo-integration-by-shoal algorithm was implemented to isolate pelagic fish shoals from sound scattering layers and to compute mean morphometric, positional and density parameters. Tree regressions were used to select and classify pelagic fish Target Strengths (TS), with reference to their spatial and temporal characteristics. The main type of pelagic fish aggregation was a large sub-surface aggregation. It was observed during all daytime periods within a radius of 400 m of the FAD. A smaller type of aggregation was observed closer to the surface and to the FAD in 65% of daytime periods. Large scattered fish were observed in 16% of daytime periods. At night, a medium-sized aggregation was detected in the sub-surface in 75% of night-time periods. The sizes of the fish inside the aggregations (determined from TS values) were lower in the small near-surface aggregation than in the large sub-surface aggregation. Mean packing densities of sub-surface medium fish and near-surface small fish aggregations (determined from TS and shoal acoustic density) were respectively 0.2 fish per m3 and 1.3 fish per m3. The acoustic methodology and results are discussed with reference to the characteristics and performance of the echosounder and to the spatial structure of pelagic fish aggregations around moored FADs in Martinique.
Fisheries Research (0165-7836) (Elsevier), 2006-06 , Vol. 82 , N. 1-3 , P. 162-175

Droits : Elsevier 2006
http://archimer.ifremer.fr/doc/2006/publication-1734.pdf
DOI:10.1016/j.fishres.2006.06.025
http://archimer.ifremer.fr/doc/00000/1734/

Éditeur(s) : HAL CCSD
Résumé : International audience
The SOX8 and SOX9 transcription factors are involved in, among others, sex differentiation, male gonad development and adult maintenance of spermatogenesis. Sox8(-/-) mice lacking Sox9 in Sertoli cells fail to form testis cords and cannot establish spermatogenesis. Although genetic and histological data show an important role for these transcription factors in regulating spermatogenesis, it is not clear which genes depend upon them at a genome-wide level. To identify transcripts that respond to the absence of Sox8 in all cells and Sox9 in Sertoli cells we measured mRNA concentrations in testicular samples from mice at 0, 6 and 18 days post-partum. In total, 621 and 629 transcripts were found at decreased or increased levels, respectively, at different time points in the mutant as compared to the control samples. These mRNAs were categorized as preferentially expressed in Sertoli cells or germ cells using data obtained with male and female gonad samples and enriched testicular cell populations. Five candidate genes were validated at the protein level. Furthermore, we identified putative direct SOX8 and SOX9 target genes by integrating predicted SOX-binding sites present in potential regulatory regions upstream of the transcription start site. Finally, we used protein network data to gain insight into the effects on regulatory interactions that occur when Sox8 and Sox9 are absent in developing Sertoli cells. The integration of testicular samples with enriched Sertoli cells, germ cells and female gonads enabled us to broadly distinguish transcripts directly affected in Sertoli cells from others that respond to secondary events in testicular cell types. Thus, combined RNA profiling signals, motif predictions and network data identified putative SOX8/SOX9 target genes in Sertoli cells and yielded insight into regulatory interactions that depend upon these transcription factors. In addition, our results will facilitate the interpretation of genome-wide in vivo SOX8 and SOX9 DNA binding data.
Andrology

hal-00877013
https://hal.archives-ouvertes.fr/hal-00877013
DOI : 10.1111/j.2047-2927.2012.00049.x
PUBMED : 23315995

Éditeur(s) : HAL CCSD
Résumé : Poster
The Lesser Caucasus in Armenia is an active volcanic and tectonic zone which resulted from the collision of the Arabian and the Eurasian plates since Neogene times. The During Quaternary, Lesser Caucasus was uplifted (0.3 mm/yr; Mitchell and Westaway, 1999) and experienced extensional tectonics times. Large lakes developed in graben structures. The diatomitic sequences of the Shamb paleo-lake (South Armenia) offer a rare opportunity to give new insights of Western Asia paleo-climate. Based on macroflora analysis, Bruch and Gabrielyan (2002) proposed a cooling and drying general climate trend through Pleistocene times in relation with a general uplift of the chain. Several questions have to be answer for this poorly investigated region. Did the climate record humid glacials and arid interglacials as suggested northward in Kazakhstan? What are the vegetation and climate responses to orbital parameters and to the monsoon? Moreover the lesser Caucasus is known as the entrance way used by the first hominids in Eurasia during Pleistocene time. How was the environment at this time? We present an integrated palynological, 40Ar/39Ar isotopic and magnetostratigraphic study for the most complete section (Joannin et al., in press). 40Ar/39Ar dating of two volcaniclastic layers provided ages of 1.24 ± 0.03 and 1.16 ± 0.02 Ma (2. Magnetostratigraphic data show that the entire Shamb section is of reversed polarity which correlates with part of the Matuyama period (1.785-1.070 Ma). Pollen assemblages and macroremains diversity revealed an alternation of glacial and interglacial phases that are compared with climate changes inferred from the global isotopic curve. The Shamb section ranges from approximately 1.300 to 1.080 Ma in age (marine isotopic stages 40 to 31). The vegetation of the Lesser Caucasus developed in a mosaic pattern in a Pleistocene continental, mostly arid climate, similar to the present-day climate. The vegetation changes record a dominant climate response to the obliquity orbital parameter. The influence of precession could not be established from the Shamb data. Pollen and macroflora both indicate that glacial periods were cold and dry and that interglacials were warm with local humidity. The early Pleistocene climatic model for Western Asia is thus similar to the climatic model for the Mediterranean area. Bruch, A., Gabrielyan, I.G., 2002. Quantitative data of the Neogene climatic development in Armenia and Nakhichevan. Acta Universitatis Carolinae – Geologica 46, 41–48. Joannin, S., Cornée, J.J., Münch, P., Fornari, M., Vasiliev, J., Krijgsman, W., Nahapetyan, S., Gabrielyan, Y., Ollivier, V., Roiron, P., Chataîgnier, C. In press. Early Pleistocene climatic cycles in continental deposits of the Lesser Caucasus of Armenia inferred from palynology, magnetostratigraphy, and 40Ar/39Ar dating. Earth and Planetary Science Letters. Mitchell, J., Westaway, R., 1999. Chronology of Neogene and Quaternary uplift and magmatism in the Caucasus: constraints from K-Ar dating of volcanism in Armenia. Tectonophysics 304, 157–186.
EGU Eurasian Climate and Tectonics
Vienne, Austria

hal-00481799
https://hal.archives-ouvertes.fr/hal-00481799

Éditeur(s) : PSIC 11 - 11th Pacific Science Inter-Congress : Pacific Countries and their Ocean: Facing Local and Global Changes / 2nd Symposium on French Research in the Pacific. March 2 - 6, 2009 Tahiti, French Polynesia.
Résumé : In aquaculture, Artemia nauplii are commonly used as live prey; and represent 40 % of the total aquaculture feed demands in the early stages. However, the production of Brine shrimp is very unstable from one year to another and in the late 90’s, only 20 % of the world aquaculture need was covered. An insufficient offer leads to higher prices of the Artemia cysts and consequently, the price of shrimp juveniles from hatchery. In New Caledonia, marine aquaculture is mainly based on the blue shrimp Litopenaeus stylirostris. From Zoea 3 to 10 days old post-larvae (P10), the shrimp are mainly fed with live preys. Eleven kilos of Artemia cyst are necessary for producing one million of P10. From a sanitary point of view, Artemia can be a virus carrier and Vibrio population increase is often detected in the larval rearing tank the day after the feeding with live prey. Up to now, Brine shrimp are delivered in excess but with the cost and sanitary problems, Saint-Vincent laboratory has started some experiments in order to optimise the use of Artemia in shrimp larval rearing. The first tests were conducted to determine the effect of the Artemia quantity on the growth and the survival rate at different post-larval stages (P8-P11, P5-P8 and M3-P3). It was shown that four to twelve times fold Artemia was necessary for P8-P11 compared to M3-P3. And it was also noticed that the “optimized”quantity of live food at M3-P3 was twice lower than the recommended amount of the hatchery feeding protocol in New Caledonia. A better knowledge of the real feed requirement in the early life of the blue shrimp will be helpful to decrease the cysts quantities used in shrimp hatcheries but also the associated sanitary impact. And further, these results will give data for developing formulated diets which will replace the live prey and will increase the biosecurity and the sustainability of the production of the blue juvenile shrimp in New Caledonia.
En aquaculture, les nauplii d’Artemia sont largement utilisés comme proies vivantes et représentent près de 40 % des besoins en aliments pour la production des stades précoces. Cependant, l’approvisionnement en Artemia peut fluctuer de façon importante d’une année sur l’autre. Ainsi vers la fin des années 90, la demande mondiale a pu être satisfaite seulement à hauteur de 20%. Les années avec une offre insuffisante correspondent à des augmentations importantes du cours mondial des cystes d’artemia avec des répercussions sur le prix des animaux juvéniles produits en écloserie. En Nouvelle-Calédonie, l’aquaculture marine est principalement basée sur la crevette bleue Litopenaeus stylirostris. Les larves de cette espèce, à partir du stade Zoé 3, se nourrissent essentiellement de proies vivantes. Ainsi pour produire un million de Post-larves de 10 jours il faut compter 11 kilos de cystes d’Artemia. Outre le problème posé par le coût, les artemii peuvent également représenter un risque sanitaire pour l’écloserie. En effet certaines souches sont infectées par des virus qui peuvent contaminer les crevettes et de façon plus générale l’introduction des artemii dans le volume d’élevage larvaire s’accompagne le plus souvent d’une flambée de la flore vibrionacée. Jusqu’à présent, les Artemii étaient distribuées en excès cependant du fait de leur coût et des risques sanitaires, le laboratoire de St Vincent a débuté un travail pour optimiser leur utilisation en production larvaire de crevette. Ainsi, nos premières expérimentation sur l’effet de la dose en artemii sur le développement et la survie des larves de crevettes ont permis de déterminer les rations optimales pour les stades larvaires P8-P11, P5-P8 et M3-P3. Nous avons ainsi montré que la ration de proies vivantes était 4 à 12 fois plus importante à P8-P11 qu’à M3-P3. Par ailleurs la dose optimale déterminée au cours de nos expérimentations était pour les stades M3-P3 deux fois moins élevée que celle préconisée par le protocole actuel des écloseries commerciales de Nouvelle-Calédonie. Nous voyons ainsi, qu’une meilleure compréhension des besoins alimentaires de la crevette au cours de son développement permettra de diminuer de façon substantielle les proies vivantes utilisées ainsi que le risque sanitaire associé. A terme, ces travaux donneront des bases au développement d’aliments inertes en remplacement des proies vivantes et à la production durable, en conditions de biosécurité, des crevettes bleues juvéniles pour la filière Calédonienne

Droits : info:eu-repo/semantics/openAccess
http://archimer.ifremer.fr/doc/00198/30877/29245.pdf
http://archimer.ifremer.fr/doc/00198/30877/

Éditeur(s) : Elsevier
Résumé : Previous studies conducted on the continental shelf in the Southeast Bay of Biscay influenced by Gironde waters (one of the two largest rivers on the French Atlantic coast) showed the occurrence of late winter phytoplankton blooms and phosphorus limitation of algal growth thereafter. In this context, the importance of dissolved organic phosphorus (DOP) for both algae and bacteria was investigated in 1998 and 1999 in terms of stocks and fluxes. Within the mixed layer, although phosphate decreased until exhaustion from winter to spring, DOP remained high and phosphate monoesters made up between I I to 65% of this pool. Total alkaline phosphatase activity (APA, V-max) rose gradually from winter (2-8 nM h(-1)) to late spring (100-400 nM h-1), which was mainly due to an increase in specific phytoplankton (from 0.02 to 3.0 nmol mu gC(-1) h(-1)) and bacterial APA (from 0.04 to 4.0 nmol mu gC(-1) h(-1)), a strategy to compensate for the lack of phosphate. At each season, both communities had equal competitive abilities to exploit DOP but, taking into account biomass, the phytoplankton community activity always dominated (57-63% of total APA) that of bacterial community (9-11%). The dissolved APA represented a significant contribution. In situ regulation of phytoplanktonic APA by phosphate (induction or inversely repression of enzyme synthesis) was confirmed by simultaneously conducted phosphate-enrichment bioassays. Such changes recorded at a time scale of a few days could partly explain the seasonal response of phytoplankton communities to phosphate depletion.
Journal of Experimental Marine Biology and Ecology (0022-0981) (Elsevier), 2005-05 , Vol. 318 , N. 2 , P. 213-225

Droits : 2005 Elsevier B.V. All rights reserved
http://archimer.ifremer.fr/doc/2005/publication-608.pdf
DOI:10.1016/j.jembe.2004.12.017
http://archimer.ifremer.fr/doc/00000/608/

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
Wasilewski et al. (1979) concluded that no magnetic remanence existed in the uppermost mantle and that even if present, such sources would be at temperatures too high to contribute to long wavelength magnetic anomalies (LWMA). However, new collections of unaltered mantle xenoliths indicate that the uppermost mantle could contain ferromagnetic minerals. 1. The analysis of some LWMA over cratons and forearcs suggest magnetic sources in the uppermost mantle. 2. The most common ferromagnetic phase in the uppermost mantle is stoichiometric magnetite. Assuming a 30 km-thick crust, and crustal and mantle geotherms of 15 °C/km and 5 °C/km, respectively, the 600 °C Curie temperature implies a 30 km-thick layer of mantle. 3. The uppermost mantle is cooler than 600 °C in Archean and Proterozoic shields (> 350 °C), subduction zones (> 300 °C) and old oceanic basins (> 250 °C). 4. Recently investigated sets of unaltered mantle xenoliths contain pure magnetite inclusions in olivine and pyroxene formed in equilibrium with the host silicate. 5. The ascent of mantle xenoliths occurs in less than a day. Diffusion rates in olivine suggest that the growth of magnetite possible within this time frame cannot account for the size and distribution of magnetite particles in our samples. 6. Demagnetization of natural remanent magnetization (NRM) of unaltered mantle xenoliths unambiguously indicates only a single component acquired upon cooling at the Earth's surface. This is most easily explained as a thermoremanent magnetization acquired by pre-existing ferromagnetic minerals as xenoliths cool rapidly at the Earth's surface from magmatic temperatures, acquired during ascent. 7. Modern experimental data suggest that the wüstite-magnetite oxygen buffer and the fayalite-magnetite-quartz oxygen buffer extend several tens of km within the uppermost mantle. 8. The magnetic properties of mantle xenoliths vary consistently across tectonic settings. In conclusion, the model of a uniformly non-magnetic mantle should be revisited. Keywords
ISSN: 0040-1951

hal-01053923
https://hal.archives-ouvertes.fr/hal-01053923
DOI : 10.1016/j.tecto.2014.01.004