Éditeur(s) : HAL CCSD Springer Verlag
Résumé : International audience
The release of polycyclic aromatic hydrocarbons (PAHs) into the environment has increased very substantially over the last decades. PAHs are hydrophobic molecules which can accumulate in high concentrations in sediments acting then as major secondary sources. Fish contamination can occur through contact or residence nearby sediments or though dietary exposure. In this study, we analyzed certain physiological traits in unexposed fish (F1) issued from parents (F0) exposed through diet to three PAH mixtures at similar and environmentally relevant concentrations but differing in their compositions. For each mixture, no morphological differences were observed between concentrations. An increase in locomotor activity was observed in larvae issued from fish exposed to the highest concentration of a pyrolytic (PY) mixture. On the contrary, a decrease in locomotor activity was observed in larvae issued from heavy oil mixture (HO). In the case of the third mixture, light oil (LO), a reduction of the diurnal activity was observed during the setup of larval activity. Behavioral disruptions persisted in F1-PY juveniles and in their offspring (F2). Endocrine disruption was analyzed using cyp19a1b:GFP transgenic line and revealed disruptions in PY and LO offspring. Since no PAH metabolites were dosed in larvae, these findings suggest possible underlying mechanisms such as altered parental signaling molecule and/or hormone transferred in the gametes, eventually leading to early imprinting. Taken together, these results indicate that physiological disruptions are observed in offspring of fish exposed to PAH mixtures through diet.
ISSN: 0944-1344

hal-01121865
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01121865
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01121865/document
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01121865/file/Exposures%20of%20zebrafish_accepted.pdf
DOI : 10.1007/s11356-015-4157-8

Éditeur(s) : HAL CCSD Springer Verlag
Résumé : International audience
ISSN: 0927-6947

hal-00508319
https://hal.archives-ouvertes.fr/hal-00508319

Éditeur(s) : HAL CCSD Springer Verlag
Résumé : The activity of the Damavand volcano (Central Alborz, northern Iran) began 1.8 Ma ago and continued up to 7 ka BP. Although the volcanic suite is clearly of shoshonitic affinity, only two petrographic types can be distinguished in the studied lavas: (1) weakly differentiated absarokites (49 < %SiO2 < 51), scattered around the volcano but with a regional extension, (2) highly differentiated banakites (59 < %SiO2 < 63), which form the bulk of the 4,000 m thick volcanic pile. All lavas are alkalic (3.7 < %K2O < 5), REE and LILE-rich (e.g., 85 < La < 148 ppm; 9 < Th < 32 ppm) and show highly fractionated REE patterns (69 < La/Yb < 115) and pronounced Nb-Ta negative anomalies. The absarokites are characterised by Sr (0.7045-0.7046) and Nd (0.51266-0.51269) isotope compositions close to the Bulk Earth values, and distinct from those of the banakites (0.7047 < Sr-87/Sr-86 < 0.7049, 0.51258 < Nd-143/Nd-144 < 0.51262). The Pb isotope ratios are also slightly lower in the absarokites than in the banakites (18.71 < Pb-206/Pb-204 < 18.77, 15.62 < Pb-207/Pb-204 < 15.63, 38.85 < Pb-208/Pb-204 < 38.91, and 18.77 < Pb-206/Pb-204 < 18.84, 15.62 < Pb-207/Pb-204 < 15.64, 38.94 < Pb-208/Pb-204 < 39.06, respectively). Overall, there is a clear tendency towards higher Sr, Pb and lower Nd isotope ratios with increasing degree of differentiation. This study suggests that the absarokites result from a low degree of partial melting (similar to 5%) of a highly metasomatized mantle source, which inherited its characteristics from an old subduction setting. The initiation of volcanic activity 1.8 Ma ago results from variations in the lithospheric thermal regime, probably related to lithospheric delamination as proposed for Anatolia (Pearce et al. 1990). The banakites are mainly generated by extensive fractional crystallisation (similar to 70%) of the absarokitic magma, with a limited amount (a few percents) of assimilation of an old crustal component, in the form of bulk assimilation or AFC processes, which both can explain the Sr, Nd and Pb isotope data.
ISSN: 1437-3254

hal-00411553
https://hal.archives-ouvertes.fr/hal-00411553
DOI : 10.1007/s00531-006-0159-6

Éditeur(s) : HAL CCSD Springer Verlag
Résumé : International audience
We provide a first-order necessary and sufficient condition for optimality of lower semicontinuous functions on Banach spaces using the concept of subdifferential. From the sufficient condition we derive that any subdifferential operator is monotone absorbing, hence maximal monotone when the function is convex.
ISSN: 0925-5001

hal-00761658
https://hal.archives-ouvertes.fr/hal-00761658
ARXIV : 1212.0532
DOI : 10.1007/s10898-013-0078-6

Éditeur(s) : HAL CCSD Springer Verlag
Résumé : International audience
ISSN: 0010-7999

hal-01664653
https://hal.archives-ouvertes.fr/hal-01664653
DOI : 10.1007/s00410-017-1394-5

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

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

Éditeur(s) : HAL CCSD Springer Verlag
Résumé : Vertical displacements on the SW-NE T (e) over capt fault (Eastern Pyrenees Axial Zone, France), which separates the Variscan Canigou-Caranca and Mont-Louis massifs, were constrained using a thermochronologic multi-method approach. Ar-40/Ar-39 data from the granitic Mont-Louis massif record its Variscan cooling history and reveal no ages younger than Early Cretaceous, while the Canigou-Caranca gneiss massif records systematically younger Ar-40/Ar-39 ages. These younger Ar-40/Ar-39 ages in the Canigou-Caranca gneiss massif are the result of partial to total rejuvenation of argon isotopic systems related to a thermal flow coeval with the Cretaceous HT-BP metamorphism in the North Pyrenean Zone. Only the deepest rocks from the Canigou-Caranca suffered this extensive Mid-Cretaceous thermal overprint probably due to differential burial around 4 km at that time. The post Mid-Cretaceous vertical displacements along the T (e) over capt fault are recorded by "low" temperature thermochronology using K-feldspar Ar-40/Ar-39, zircon and apatite fission track and (U-Th)/He datings. The Mont-Louis granite samples experienced a long period of protracted cooling reflecting a lack of thermo-tectonic activity in this area from Late Palaeozoic to Early Cenozoic, followed by cooling from 55-60 Ma to Late Eocene at a mean rate of 15-20 degrees C/Ma in the final stage. This cooling stage corresponds to T (e) over capt fault reactivation with a reversed component, promoting exhumation of the Mont-Louis roof zone contemporaneously with the south-vergent Pyrenean thrusting. In the Canigou-Caranca massif, the main cooling event occurred from 32 to 18 Ma at a maximum rate of 30 degrees C/Ma during Early Oligocene followed by a more moderate rate of 3 degrees C/Ma from Late Oligocene to Early Burdigalian, coeval with the normal reactivation of the T (e) over capt fault in brittle conditions that accommodated the final exhumation of the massif during the opening of the Gulf of Lion.
ISSN: 1437-3254

hal-00411442
https://hal.archives-ouvertes.fr/hal-00411442
DOI : 10.1007/s00531-007-0179-x

Éditeur(s) : HAL CCSD Springer Verlag (Germany) Springer Verlag
Résumé : International audience
The dissolution of carbonate rocks usually leads to both porosity (ϕ) and permeability (k) increase. We present experimental evidences and physical-based models of positive and anti-correlated dynamics of k and ϕ observed during dissolution experiments of carbonate rocks. We study the way the rate of change of ϕ and k is controlled by the degree of undersaturation of the percolating solution for two different types of carbonate rocks. We document the occurrence of an anti-correlated k−ϕ trend when the flowing fluid (deionized water) has a weak capacity of dissolution. A positive correlation is found when CO2 is added to the deionized water to increase the potential dissolution rate. Detailed analyses of the microstructures of the rock performed by X-ray microtomography reveal that low dissolution rate favors detachment of solid particles and their subsequent accumulation at the pore-throat inlet. Particles are detached from the rock matrix due to the differential dissolution rate of the indurated grains and the microporous cement. We then propose a simple phenomenological model to interpret the effect of the pore-throat clogging by the accumulation of partially dissolved carbonate particles. We conjecture that permeability is controlled by the decrease of the effective hydraulic radius and the increase of the tortuosity due to partial and localized obstruction of the pore network. Conversely, increasing the level of undersaturation of the flowing solution leads to an augmented potential of dissolving most of the transported particles before they reach the throats. In this case, both k and ϕ increase and display power-law correlations.
ISSN: 0169-3913

hal-01174145
https://hal.archives-ouvertes.fr/hal-01174145
DOI : 10.1007/s11242-015-0456-2

Éditeur(s) : HAL CCSD Springer Verlag (Germany) Springer Verlag
Résumé : International audience
Arenal volcano is nearly unique among arc volcanoes with its 42 year long (1968–2010) continuous, small-scale activity erupting compositionally monotonous basaltic andesites that also dominate the entire, ~7000 year long, eruptive history. Only mineral zoning records reveal that basaltic andesites are the result of complex, open-system processes deriving minerals from a variety of crystallization environments and including the episodic injections of basalt. The condition of the mafic input as well as the generation of crystal-rich basaltic andesites of the recent, 1968–2010, and earlier eruptions were addressed by an experimental study at 200 MPa, 900–1,050 °C, oxidizing and fluid-saturated conditions with various fluid compositions [H2O/(H2O + CO2) = 0.3–1]. Phase equilibria were determined using a phenocryst-poor (~3 vol%) Arenal-like basalt (50.5−wt% SiO2) from a nearby scoria cone containing olivine (Fo92), plagioclase (An86), clinopyroxene (Mg# = 82) and magnetite (Xulvö = 0.13). Experimental melts generally reproduce observed compositional trends among Arenal samples. Small differences between experimental melts and natural rocks can be explained by open-system processes. At low pressure (200 MPa), the mineral assemblage as well as the mineral compositions of the natural basalt were reproduced at 1,000 °C and high water activity. The residual melt at these conditions is basaltic andesitic (55 wt% SiO2) with 5 wt% H2O. The evolution to more evolved magmas observed at Arenal occurred under fluid-saturated conditions but variable fluid compositions. At 1,000 °C and 200 MPa, a decrease of water content by approximately 1 wt% induces significant changes of the mineral assemblage from olivine + clinopyroxene + plagioclase (5 wt% H2O in the melt) to clinopyroxene + plagioclase + orthopyroxene (4 wt% H2O in the melt). Both assemblages are observed in crystal-rich basalt (15 vol%) and basaltic andesites. Experimental data indicate that the lack of orthopyroxene and the presence of amphibole, also observed in basaltic andesitic tephra units, is due to crystallization at nearly water-saturated conditions and temperatures lower than 950 °C. The enigmatic two compositional groups previously known as low- and high-Al2O3 samples at Arenal volcano may be explained by low- and high-pressure crystallization, respectively. Using high-Al as signal of deeper crystallization, first magmas of the 1968–2010 eruption evolved deep in the crust and ascent was relatively fast leaving little time for significant compositional overprint by shallower level crystallization.
ISSN: 0010-7999

hal-01115717
https://hal.archives-ouvertes.fr/hal-01115717
DOI : 10.1007/s00410-014-1040-4

Éditeur(s) : HAL CCSD Springer Verlag
Résumé : Intraguild predation (IGP) is a type of biological interaction involving the killing and consuming of competing species that exploit similar and often limited resources. This phenomenon is widespread among a great variety of taxonomic groups and has already been reported for mosquito (Diptera: Culicidae) larvae. Moreover, the larvae of certain mosquito species of the tribe Sabethini have evolved modified mouthparts ending in rigid apical structures signaling their capacity to be effective intraguild predators. We assumed that IGP confers a selective advantage under severe competitive conditions by both providing an immediate energetic gain and reducing potential competition. Because potential competition is likely to increase with decreasing habitat size, we hypothesized that the proportion of species with modified mouthparts would increase in smaller aquatic habitats. We tested this hypothesis by examining the mosquito species naturally associated with phytotelmata of decreasing sizes in French Guiana. We show that the degree of specialization in mosquito-phytotelm associations is high, suggesting a long coevolutive process. Indeed, short-term interaction experiments confirmed that species with modified mouthparts are able to prey upon similarly-sized intraguild prey and are, thus, effective intraguild predators. In addition, these species are larger and associated with smaller phytotelmata than those with typical mouthparts. Moreover, below a certain threshold of phytotelm size, only species with modified mouthparts were present. These results show that IGP confers a selective advantage under severe competitive conditions and results from the coadaptation of mosquito species to their specific phytotelm habitat. The presence of functionally analogous structures in different mosquito genera also implies that IGP has emerged from convergent evolution in small phytotelmata.
ISSN: 0269-7653

hal-01603304
https://hal.archives-ouvertes.fr/hal-01603304
DOI : 10.1007/s10682-016-9862-3
PRODINRA : 405771

Éditeur(s) : HAL CCSD Springer Verlag (Germany) Springer Verlag
Résumé : International audience
Replenished axial melt lenses at fast-spreading mid-oceanic ridges may move upward and intrude into the overlying hydrothermally altered sheeted dikes, resulting in high-grade contact metamorphism with the potential to trigger anatexis in the roof rocks. Assumed products of this process are anatectic melts of felsic composition and granoblastic, two-pyroxene hornfels, representing the residue after partial melting. Integrated Ocean Drilling Program Expeditions 309, 312, and 335 at Site 1256 (eastern equatorial Pacific) sampled such a fossilized oceanic magma chamber. In this study, we simulated magma chamber roof rock anatectic processes by performing partial melting experiments using six different protoliths from the Site 1256 sheeted dike complex, spanning a lithological range from poorly to strongly altered basalts to partially or fully recrystallized granoblastic hornfels. Results show that extensively altered starting material lacking primary magmatic minerals cannot reproduce the chemistry of natural felsic rocks recovered in ridge environments, especially elements sensitive to hydrothermal alteration (e.g., K, Cl). Natural geochemical trends are reproduced through partial melting of moderately altered basalts from the lower sheeted dikes. Two-pyroxene hornfels, the assumed residue, were reproduced only at low melting degrees (<20 vol%). The overall amphibole absence in the experiments confirms the natural observation that amphibole is not produced during peak metamorphism. Comparing experimental products with the natural equivalents reveals that water activity (aH2O) was significantly reduced during anatectic processes, mainly based on lower melt aluminum oxide and lower plagioclase anorthite content at lower aH2O. High silica melt at the expected temperature (1000–1050 °C; peak thermal overprint of two-pyroxene hornfels) could only be reproduced in the experimental series performed at aH2O = 0.1.
ISSN: 0010-7999

hal-01174139
https://hal.archives-ouvertes.fr/hal-01174139
DOI : 10.1007/s00410-015-1136-5

Éditeur(s) : HAL CCSD Springer Verlag
Résumé : International audience
ISSN: 1387-3547

hal-01093626
https://hal-agroparistech.archives-ouvertes.fr/hal-01093626
DOI : 10.1007/s10530-010-9714-y

Éditeur(s) : HAL CCSD Springer Verlag
Résumé : International audience
The actin cytoskeleton is a dynamic structure that provides an interactive platform for organelles and cellular components. It also serves as track for membranes and vesicles that move via myosin. The actin cytoskeleton of Symbiodinium is a well-organized reticular structure suggestive of multiple membrane interactions, very likely including those of the chloroplast. The Symbiodinium chloroplast membrane network is, in turn, a highly organized structure, suggestive of being under the control of an organizing network. We visualized the chloroplast membranes of cultured Symbiodinium sp. under various light conditions and observed changes dependent on illumination intensity. Since we suspected interaction between these two organelles, and we knew that the Symbiodinium actin cytoskeleton collapses upon treatment with either latrunculin B, an actin microfilament-disrupting agent, or butanedione monoxime, a myosin function inhibitor, we tested the Symbiodinium sp. oxygen evolution in their presence. Upon latrunculin B addition, the oxygen production decreased compared to non-treated cells; however, this was not observed after a 24 h latrunculin treatment. On the contrary, butanedione monoxime treatment caused a non-recoverable dysfunction of the chloroplast causing a severe loss in oxygen production even after long-term exposure. Using electron microscopy, we observed an alteration of the Symbiodinium sp. chloroplast distribution after latrunculin B treatment, with respect to untreated cells. Furthermore, a thorough disorganization of the chloroplast grana was observed after butanedione monoxime treatment. These data suggest that an actomyosin system would be important for chloroplast organization and distribution, and critical for normal photosynthetic function of Symbiodinium sp.
ISSN: 0166-8595

hal-01546164
https://hal.archives-ouvertes.fr/hal-01546164
DOI : 10.1007/s11120-015-0142-9

Éditeur(s) : HAL CCSD Springer Verlag
Résumé : International audience
ISSN: 0029-8549

hal-00524665
https://hal.archives-ouvertes.fr/hal-00524665

Éditeur(s) : HAL CCSD Springer Verlag
Résumé : ODP Leg 209 Site 1274 mantle peridotites are highly refractory in terms of lack of residual clinopyroxene, olivine Mg# (up to 0.92) and spinel Cr# (∼0.5), suggesting high degree of partial melting (>20%). Detailed studies of their microstructures show that they have extensively reacted with a pervading intergranular melt prior to cooling in the lithosphere, leading to crystallization of olivine, clinopyroxene and spinel at the expense of orthopyroxene. The least reacted harzburgites are too rich in orthopyroxene to be simple residues of low-pressure (spinel field) partial melting. Cu-rich sulfides that precipitated with the clinopyroxenes indicate that the intergranular melt was generated by no more than 12% melting of a MORB mantle or by more extensive melting of a clinopyroxene-rich lithology. Rare olivine-rich lherzolitic domains, characterized by relics of coarse clinopyroxenes intergrown with magmatic sulfides, support the second interpretation. Further, coarse and intergranular clinopyroxenes are highly depleted in REE, Zr and Ti. A two-stage partial melting/melt–rock reaction history is proposed, in which initial mantle underwent depletion and refertilization after an earlier high pressure (garnet field) melting event before upwelling and remelting beneath the present-day ridge. The ultra-depleted compositions were acquired through melt re-equilibration with residual harzburgites. Electronic supplementary material Supplementary material is available in the online version of this article at ;; and is accessible for authorized users
ISSN: 0010-7999

hal-00404655
https://hal.archives-ouvertes.fr/hal-00404655
DOI : 10.1007/s00410-006-0148-6

Éditeur(s) : HAL CCSD Springer Verlag
Résumé : International audience
ISSN: 1385-1292

hal-01295221
https://hal.archives-ouvertes.fr/hal-01295221
DOI : 10.1007/s11117-016-0412-6

Éditeur(s) : HAL CCSD Springer-Verlag
Résumé : International audience
With hull-mounted multibeam echosounder data, wereport for the first time along the active Ecuadorian margin,acoustic signatures of water column fluid emissions and seep-relatedstructures on the seafloor. In total 17 flare-shaped acousticanomalies were detected from the upper slope (1250 m) to the shelfbreak (140 m). Nearly half of the flare-shaped acoustic anomaliesrise 200–500 m above the seafloor. The base of the flares is generallyassociated with high-reflectivity backscatter patchescontrasting with the neighboring seafloor. We interpret these flaresas caused by fluid escape in the water column, most likely gases.High-resolution seismic profiles show that most flares occur closeto the surface expression of active faults, deformed areas, slopeinstabilities or diapiric structures. In two areas tectonic deformationdisrupts a Bottom Simulating Reflector (BSR), suggesting thatburied frozen gas hydrates are destabilized, thus supplying free gasemissions and related flares. This discovery is important as it opensthe way to determine the nature and origin of the emitted fluids andtheir potential link with the hydrocarbon system of the forearcbasins along the Ecuadorian margin.
ISSN: 0033-4533

insu-01267238
https://hal-insu.archives-ouvertes.fr/insu-01267238
DOI : 10.1007/s00024-015-1230-7

Éditeur(s) : HAL CCSD Springer Verlag/EDP Sciences
Résumé : absent
ISSN: 1286-4560

hal-01032265
https://hal.archives-ouvertes.fr/hal-01032265
DOI : 10.1051/forest:2005048

Éditeur(s) : HAL CCSD Springer Verlag
Résumé : International audience
Glioblastoma (GB) is the most frequent and aggressive type of primary brain tumor. Recurrences are mostly located at the margin of the resection cavity in the peritumoral brain zone (PBZ). Although it is widely believed that infiltrative tumor cells in this zone are responsible for GB recurrence, few studies have examined this zone. In this study, we analyzed PBZ left after surgery with a variety of techniques including radiology, histopathology, flow cytometry, genomic, transcriptomic, proteomic, and primary cell cultures. The resulting PBZ profiles were compared with those of the GB tumor zone and normal brain samples to identify characteristics specific to the PBZ. We found that tumor cell infiltration detected by standard histological analysis was present in almost one third of PBZ taken from an area that was considered normal both on standard MRI and by the neurosurgeon under an operating microscope. The panel of techniques used in this study show that the PBZ, similar to the tumor zone itself, is characterized by substantial inter-patient heterogeneity, which makes it difficult to identify representative markers. Nevertheless, we identified specific alterations in the PBZ such as the presence of selected tumor clones and stromal cells with tumorigenic and angiogenic properties. The study of GB-PBZ is a growing field of interest and this region needs to be characterized further. This will facilitate the development of new, targeted therapies for patients with GB and the development of approaches to refine the per-operative evaluation of the PBZ to optimize the surgical resection of the tumor.
ISSN: 0167-594X

hal-01117083
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01117083
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01117083/document
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01117083/file/Characterizing%20the%20Peritumoral%20Brain%20Zone_accepted.pdf
DOI : 10.1007/s11060-014-1695-8

Éditeur(s) : HAL CCSD Springer Verlag
Résumé : The patterns of the distribution of fungal species and their potential interactions with trees remain understudied in Neotropical rainforests, which harbor more than 16,000 tree species, mostly dominated by endomycorrhizal trees. Our hypothesis was that tree species shape the non-mycorrhizal fungal assemblages in soil and litter and that the diversity of fungal communities in these two compartments is partly dependent on the coverage of trees in the Neotropical rainforest. In French Guiana, a long-term plantation and a natural forest were selected to test this hypothesis. Fungal ITS1 regions were sequenced from soil and litter samples from within the vicinity of tree species. A broad range of fungal taxa was found, with 42 orders and 14 classes.Significant spatial heterogeneity in the fungal communities was found without strong variation in the species richness and evenness among the tree plots. However, tree species shaped the fungal assemblages in the soil and litter, explaining up to 18 % of the variation among the communities in the natural forest.These results demonstrate that vegetation cover has an important effect on the structure of fungal assemblages inhabiting the soil and litter in Amazonian forests, illustrating the relative impact of deterministic processes on fungal community structures in these highly diverse ecosystems.
ISSN: 0095-3628

hal-01595373
https://hal.archives-ouvertes.fr/hal-01595373
DOI : 10.1007/s00248-016-0839-0
PRODINRA : 395655
PUBMED : 27645139