Éditeur(s) : Pêche thonière et dispositifs de concentration de poissons, Caribbean-Martinique, 15-19 Oct 1999
Résumé : This paper develops a comparative overview of the development of Fish Aggregating Devices (or fads) by the tropical purse seine fisheries in various ocean areas (Atlantic, Indian, Western and Eastern Pacific Oceans). First, a comparative review of fishery statistics is developed. Recent catches on fads by purse seiners can be estimated at a level of one million tons yearly. This comparison allows to describe the fishing zones and catch trends over time, the species composition and size taken in the various fad fisheries. Skipjack tuna is the dominant species in most fad fisheries, but significant amounts of yellowfin and bigeye are also frequently taken under fads. The paper also presents an overview of various observer data concerning the by-catches of the various fisheries using fads. This comparison allows to estimate the total worldwide yearly by-catches at about 100,000 t, and their species composition in each ocean. The fad technology used in the various oceans by purse seiners is described. The recent use of fads by purse seiners has introduced major uncertainties in most stock assessments, because analyses are hampered by changes in the fishing effort in a fad fishery, by changes in fishing zones and in sizes caught. As a last point, the management of fads presently done or in view by the various tuna bodies are introduced. It appears that the present massive use of fads worldwide is perhaps an unsafe fishing mode, which could produce serious overfishing of many stocks. There is then a consensus that the use of fads needs to be controlled and limited to sustainable biological levels.

Droits : Ifremer
http://archimer.ifremer.fr/doc/00042/15278/12664.pdf
http://archimer.ifremer.fr/doc/00042/15278/

Résumé : Les stocks des éléments dans les sols, et en particulier ceux du carbone, sont en constante évolution sous l’effet de facteurs naturels (climat, végétation, teneurs en argiles, etc.) et anthropiques (usages des sols, etc.). Notre objectif est donc, (i) de mieux comprendre les relations entre type de sol, système de culture et quantité de carbone stockée, (ii) d’étudier les conséquences des changements d’usage et de gestion des terres sur les formes de matière organique dans les sols et (iii) de préciser le rôle de la matière organique sur les propriétés physiques des sols.Des situations agro-pédologiques représentatives des trois grands modèles minéralogiques des sols tropicaux (Sols à allophanes (argiles non cristallisées), Sols à argiles 1/1 et Sols à argiles 2/1) et présentant des systèmes culturaux de différents niveaux d’intensification (monocultures intensives destinées à l’exportation, systèmes paysans faiblement intensifiés, etc.) ont ainsi été sélectionnées sur les sols de Martinique. Par ailleurs, afin de limiter les effets des usages antérieurs des parcelles, nous avons généralement choisi des situations culturales âgées au minimum de 3 ans.L’analyse des stocks de carbone des différentes parcelles fait apparaître des comportements différents : dans les sols à allophanes, il y a un effet de la minéralogie sur la stabilisation des matières organiques ; dans les sols à argiles cristallisées, il existe une corrélation entre la teneur en carbone (ou le stock organique) et la texture (ou teneur en éléments fins), aussi bien pour les situations non cultivées que pour les situations sous cultures. L’amplitude des variations (diminution) des stocks en carbone observées sous l’effet de différents modes de gestion des sols, dépend elle aussi de la texture : dans les sols sableux, la potentialité de séquestration du carbone est faible ou nulle, en revanche, les potentialités de stockage du carbone sont plus fortes dans les sols argileux.L’estimation des stocks totaux de carbone à l’échelle de la Martinique, pour un mètre de profondeur et pour une situation moyenne entre les cartes d’usage des terres de 1969/1970 et 1979/1980, s’élèvent à 11,859 Mt de C calculés pour 95,8% de la surface.La distribution de la matière organique du sol varie avec la texture du sol : dans les sols sableux, à faibles teneurs en matière organique, les matières organiques sont principalement associées aux fractions sableuses ; dans les sols argileux, plus riches en matières organiques, 50 à 60 % de la matière organique sont associées à la fraction argileuse. De même, la dynamique de la matière organique dépend également de la texture du sol : dans les sols sableux, les variations des stocks organiques sont essentiellement dues à la perte ou à l’accumulation en carbone de la fraction sableuse ; dans les sols argileux, la fraction argileuse participe de manière prépondérante aux variations des stocks organiques de ces sols lors de leur mise en culture ou en prairie ; les sols sablo-argileux ont un comportement intermédiaire entre ces deux pôles.La stabilité structurale varie avec la minéralogie. Les andosols (ou ALL) présentent un haut degré d’agrégation et de stabilité, du à la présence d’allophanes et à leur association particulière avec les composés organiques. Dans les sols à argiles cristallisées, la stabilité de l’agrégation est plus élevée dans les sols à argiles 1/1 (ou LAC) ; les valeurs les plus faibles sont généralement observées dans les parcelles sur sols à argiles 2/1 (ou HAC). En outre, la mise en culture se traduit généralement par une diminution de la stabilité de l’agrégation.L’intensification des cultures (labours fréquents, faibles restitutions de matière organique au sol, etc.) accentue la perte de la stabilité de l’agrégation provoquée par la mise en culture, en particulier dans les parcelles sur sols à argiles 2/1 (ou HAC).
Soils elements stocks, and particularly those of carbon, are in constant evolution under natural factors effect (climate, vegetation, clays content, etc) and anthropic factors effect (soils uses, etc). Our objective is thus, (i) to better understand the relations between soil, farming system and stored carbon quantity, (ii) to study the consequences of soils uses changes and of soils managements changes on organic matter shapes in soil and (iii) to specify organic matter role on soil properties physics.Representative agri-pedological situations of the three great mineralogical models of tropical soils (allophonic soils (not crystallized clays), 1:1 clay soils and 2:1 clay soils) and presenting agricultural systems of various levels of intensification (intensive monocultures intended for export, slightly intensified farming systems, etc) were thus selected in the soils of Martinique. In addition, to limit the effects of their former uses, we generally chose to the minimum 3 years old farming situations.The analysis of the various lands carbon stocks reveals different behaviors: in allophonic soils, a correlation exists between carbon content (or organic stock) and texture (or fine elements content), as well for not cultivated as for cultivated situations. Variations ranges (reduction) of carbon stocks observed under various management soils systems effect, also depends on texture: in sandy soils, carbon sequestration potentiality is low or null, on the other hand, carbon storage potentialities are higher in clay soils.The estimation of total carbon stocks on the scale of Martinique, for one meter of depth and for and average situation between the use soils charts of 1969/70 and 1979/80, rises to 11,859 Mt of C calculated for 95,8% of the surface.Soil organic matter distribution varies with soil texture: in sandy soils, with low contents of organic matter, organics matters are mainly associated with the sandy fractions; in clay soils, richer in organic matters, 50 to 60% of the organic matters are associated with the argillaceous fraction. In the same way, the organic matter dynamics also depends on soil texture: in sandy soils, organic stocks variations are primarily due to carbon loss or accumulation of the sandy fraction; in clay soils, the argillaceous fraction takes part in a dominating way in organic stocks variations of these soils at the time of their setting in culture or meadow; the sand-clay soils have an intermediate behavior between these two poles.Structural stability varies with mineralogy. Andosols (or ALL) present a high degree of aggregation and stability, due to the presence of allophones and their particular association with the organics compounds. In crystallized clay soils, aggregation stability is higher in 1:1 clay soils (or LAC); the lowest values are generally observed in the lands on 2:1 clay soils (or HAC). Moreover, culture setting generally results in aggregation stability reduction.Cultures intensification (frequent ploughings, low organic matter restitutions to the soil, etc) accentuates aggregation stability loss caused by culture setting, particularly in lands on 2:1 clay soils (or HAC).

http://www.theses.fr/2012AGUY0513/document

Éditeur(s) : HAL CCSD
Résumé : Biogenic volatile organic compound (BVOCs) emissions play an important role in regional air quality and global atmospheric chemistry. In addition, these natural VOC emissions serve important biological functions including attracting and repelling pollinators and herbivores. Some biological organisms use ambient air as a communication medium and the oxidation of these compounds brings about the concentration gradients sensed by insects and other organisms. Isoprene is the predominant BVOC emitted by vegetation and tropical forests are the dominant global source. This compound is very reactive in the atmosphere and contributes to the reactions that control tropospheric oxidant concentrations and thus the concentrations and lifetimes of longer-lived species. This paper presents a study on the seasonal variations in isoprene and some other significant BVOCs such as µ-pinene, µ-pinene, limonene, e-µ ocimene and longifolene, measured at the Guyaflux Tower located in a wet tropical forest in Paracou French Guiana (5o16´54´´N, 52o54´44´´W), during the year of 2011, using the Relaxed Eddy Accumulation technique at approximately 20 meters high above the canopy. The results show a lower concentration of isoprene during the month of February and March which correspond to the wet season with an average of 0,545 µg/m3 and 0,341 µg/m3, respectively followed by a slight increase in middle April (still wet season) and a higher concentration later in mid-June. The same behavior was observed for µ-pinene with higher concentrations for the same periods as isoprene however with a smaller increase. All the other compounds had concentrations below 1 µg/m3during the whole year: The monoterpene, e-µ ocimene, was observed and is known as a stress compound but the vegetation at the site did not face any known severe stress condition such as excessive drought or flooding. Concerning the fluxes, the results showed that just a small amount of BVOCs were deposited by wet or dry process and the majority of them were released in the atmosphere. Isoprene was by far the biogenic volatile organic compound with the highest concentration and flux, followed by alpha-pinene. The lowest concentration and flux rate for all the studied compounds was observed during the months of March and late July and beginning of August indicating a lower production of those BVOCs by vegetation during those periods. Previous limited studies in Amazonia and the Congo suggested that a higher concentration and flux rate of isoprene and µ-pinene should be expected during the dry season with lower emissions during the wet season, which is in relative agreement with what was observed at this tropical forest site in French Guiana. The exceptions were observed in April and June which correspond to a long wet period in which the concentration of isoprene and µ-pinene increased more than it was expected for this time of the year. The observations will be compared to output from the global chemistry transport model CAM-chem, which includes the MEGAN biogenic emissions model.
10th EGU General Assembly
vienne, Austria

hal-01204214
https://hal.archives-ouvertes.fr/hal-01204214
PRODINRA : 276525

Éditeur(s) : HAL CCSD Elsevier
Résumé : The correct characterization of the effective reactive transport dynamics is an important issue for modeling reactive transport on the Darcy scale, specifically in situations in which reactions are localized, that is when different reactions occur in different portions of the porous medium. Under such conditions the conventional approach of homogenizing only the porous medium chemistry is not appropriate. We consider here reactive transport in a porous medium that is characterized by mass transfer between a mobile and a distribution of immobile regions. Chemical and physical heterogeneities are reflected by distributions of kinetic reaction rate constants and residence times in the immobile zones. We derive an effective reactive transport equation for the mobile solute that is characterized by non-local physical mass transfer and reaction terms. Specifically, chemical heterogeneity is upscaled in terms of a reactive memory function that integrates both chemical and physical heterogeneity. Mass transfer limitations due to physical heterogeneity yield effective kinetic rate coefficients that can be much smaller than the volumetric average of the local scale coefficients. These results help to explain and quantify the often reported discrepancy between observed field reaction rate constants and the ones obtained under well mixed laboratory conditions. Furthermore, these results indicate that transport under physical and chemical heterogeneity cannot be upscaled separately.
ISSN: 0169-7722

hal-00617674
https://hal.archives-ouvertes.fr/hal-00617674
DOI : 10.1016/j.jconhyd.2010.06.002

Éditeur(s) : HAL CCSD
Résumé :   Diffusion du document : INRA Antilles-Guyane, UMR ECOFOG, F97387 Kourou, Guyane (France) Diplôme : DEA
il s'agit d'un type de produit dont les métadonnées ne correspondent pas aux métadonnées attendues dans les autres types de produit : DISSERTATION
This work on tropic al humid forest of Paracou includes 16 permanent sample plots covering a total surface of 119 hectares. Ten hectares of them are taken up by floodplains which characteristic is a continuous no-deep underground water level with phases of strong surface water logging. Three items have been studied : (i) Checking that during dry season the maps of the underground water level including its limits are reliable, (ii) Characterising the most suitable ecological niches for certain species, (iii) Additional updating the floodplains characterisation by precisely analysing the chemical soil content as well as the physiological reaction of the Symphonia Globulifera . Checking the underground water level in dry season enabled to put down to a quite good measurement reliability by GIS. The classification ecological of species proposed in this work is based on the relative density in floodplain and drain soil very similar to that which concerns a surface located ten or more kilometres further. This lets us assess that this classification is of a good reliability as long as the climate conditions are quite similar to ours in Paracou. Furthermore the presence of pneumatophores in the Symphonia Globulifera is a good biological criterion as long as it shows a long time ground moisture saturation. By analysing the life litter and the soil we mentioned that the leaf content and the soil content indicate a better nutritional value (phosphorus, calcium and potassium) in the floodplains. For phosphorus the relation between the life litter and the soil results put forward that the Olsen method gives a better explanation of the real phosphorus availability for the trees.
Le dispositif de recherche sur la forêt tropicale humide de Paracou est composé de 16 parcelles permanentes couvrant au total 119 ha, dont 10 ha sont occupés par des bas-fonds, caractérisés par l'existence permanente d'une nappe peu profonde et par des périodes de fort engorgement en surface. Notre étude avait trois objectifs : (i) vérifier la fiabilité des cartes de la profondeur de nappe en saison sèche, qui délimitent ces bas-fonds, (ii) caractériser les préférences écologiques de quelques espèces et (iii) compléter la caractérisation des bas-fonds par l'analyse de la richesse chimique du sol et l'étude de la réaction physiologique du Symphonia globulifera. La vérification sur la profondeur de nappe en saison sèche a montré que les imprécisions des cartes étaient d'ampleur limitée, sans incidence forte par rapport à l'ensemble des données. Le classement écologique des espèces proposé dans cette étude, basé sur leurs densités relatives dans les bas-fonds et hors des bas-fonds, est très similaire à celui présenté par une autre étude, dans un dispositif situé à plusieurs dizaines de kilomètres. Cela suggère que ce classement a une bonne validité, tant que les conditions climatiques ne diffèrent pas trop de celles rencontrées à Paracou. Par ailleurs, la présence des pneumatophores du Symphonia globulifera est un bon critère biologique signalant un engorgement hydrique prolongé du sol. Au niveau des analyses de la litière et du sol, les teneurs foliaires et les teneurs dans le sol semblent indiquer que la nutrition en phosphore, calcium et potassium est meilleure en bas-fonds. Au niveau de la méthode de mesure du phosphore assimilable, les relations entre les résultats de la litière et celles du sol suggèrent que la méthode d'Olsen rend mieux compte de la disponibilité effective du phosphore pour les arbres de la forêt tropicale humide que la méthode de Duchaufour.
https://hal.archives-ouvertes.fr/hal-01189229

hal-01189229
https://hal.archives-ouvertes.fr/hal-01189229
PRODINRA : 17050

Éditeur(s) : HAL CCSD American Geophysical Union (AGU)
Résumé : International audience
We use digital elevation models and satellite imagery data completed with field observations to develop an integrated morphotectonic analysis of the anomalous topography of the Central Cordillera of Patagonia between 46 degrees S and 48 degrees S, in a region overlying subducted segments of the Chile Spreading Ridge. This region shows a number of peculiar features, not expected in a normal subduction-related belt located away from a buried spreading center. First, it is characterized by overall short-wavelength topography and highly contrasted reliefs, typical of deeply incised young mountain belts, but surprisingly, also by an average very low elevation of similar to 900 m. Second, the Cordillera lacks central high reliefs; instead, there is a central, depressed domain with average low slope gradients including the deepest point of the study area (300 m below sea level in the bottom of Lake General Carrera/Buenos Aires). This depressed area is flanked by western and eastern regions of higher elevation having opposite general slope dips. To the east, the central Patagonian Cordillera is now separated from the flat plains of the Pampean domain (representing its former piedmont) and several elevated basaltic plateaus (mesetas) by 160 degrees N-180 degrees N trending morphotectonic corridors and the western border scarps of the mesetas. These scarps correspond to neotectonic features controlled by recent vertical faults, mostly active after 3 Ma. Remnants of a former peneplain, the Avellanos surface, are widespread within the entire Cordilleran region. From geological evidence, this peneplain formed between 15 and 4 Ma and was connected originally with the mesetas domain and now is dissected by these corridors. It is shown that a negative inversion related to extensional and strike-slip faulting occurred in the frontal region of the Cordillera at 3 Ma synchronously with the emplacement of magmatic products. Timing of the extensional deformation in central Patagonia is concomitant with the migration at depth of different segments of the South Chile Ridge, which entered the trench at 6 and 3 Ma, respectively, and the consequent opening of a slab window allows asthenospheric hot mantle to reach lithospheric regions. Finally, migration of segments of the Chile Spreading Ridge since 6 Ma triggered regional uplift of the Cordillera followed by limited extension in relation with increased thermal weakening of the crust.
ISSN: 0278-7407

hal-00486334
https://hal.archives-ouvertes.fr/hal-00486334
DOI : 10.1029/2009TC002453

Éditeur(s) : HAL CCSD National Academy of Sciences
Résumé : International audience
The integration of foreign genetic information is central to the evolution of eukaryotes, as has been demonstrated for the origin of the Calvin cycle and of the heme and carotenoid biosynthesis pathways in algae and plants. For photosynthetic lineages, this coordination involved three genomes of divergent phylogenetic origins (the nucleus, plastid, and mitochondrion). Major hurdles overcome by the ancestor of these lineages were harnessing the oxygen-evolving organelle, optimizing the use of light, and stabilizing the partnership between the plastid endosymbiont and host through retargeting of proteins to the nascent organelle. Here we used protein similarity networks that can disentangle reticulate gene histories to explore how these significant challenges were met. We discovered a previously hidden component of algal and plant nuclear genomes that originated from the plastid endosymbiont: symbiogenetic genes (S genes). These composite proteins, exclusive to photosynthetic eukaryotes, encode a cyanobacterium-derived domain fused to one of cyanobacterial or another prokaryotic origin and have emerged multiple, independent times during evolution. Transcriptome data demonstrate the existence and expression of S genes across a wide swath of algae and plants, and functional data indicate their involvement in tolerance to oxidative stress, phototropism, and adaptation to nitrogen limitation. Our research demonstrates the ``recycling'' of genetic information by photosynthetic eukaryotes to generate novel composite genes, many of which function in plastid maintenance.
ISSN: 0027-8424

hal-01544793
https://hal.archives-ouvertes.fr/hal-01544793
DOI : 10.1073/pnas.1517551113

Éditeur(s) : HAL CCSD AGU and the Geochemical Society
Résumé : International audience
Analysis of the microstructures in the km-scale mantle shear zone that separates the northern and the central parts of the Lanzo peridotite massif provides evidence of an evolution in time and space of deformation processes accommodating shearing in the shallow mantle within an extensional setting. This shear zone displays an asymmetric distribution of deformation facies. From south to north, gradual reorientation of the foliation of coarse porphyroclastic plagioclase-bearing peridotites is followed by development of protomylonites, mylonites, and mm-scale ultramylonite bands. A sharp grain size gradient marks the northern boundary. Early deformation under near-solidus conditions in the south is recorded by preservation of weakly deformed interstitial plagioclase and almost random clinopyroxene and plagioclase crystal orientations. Feedback between deformation and melt transport probably led to melt focusing and strain weakening in the shear zone. Overprint of melt-rock reaction microstructures by solid-state deformation and decrease in recrystallized grain size in the protomylonites and mylonites indicate continued deformation under decreasing temperature. Less enriched peridotite compositions and absence of ultramafic dykes or widespread melt-impregnation microstructures north of the shear zone and clinopyroxene and amphibole enrichment in the mylonites and ultramylonites suggest that the shear zone acted as both a thermal barrier and a high-permeability channel for late crystallizing fluids. These observations, together with chemical data indicating faster cooling of central Lanzo relative to the northern body, corroborate that this shear zone is a mantle detachment fault. All deformation facies have crystal preferred orientations consistent with deformation by dislocation creep with dominant activation of the (010)[100] and (100)[001] systems in olivine and orthopyroxene, respectively. Dynamic recrystallization produces dispersion of olivine CPO but not a change of dominant deformation mechanism. Evidence for activation of grain boundary sliding is limited to mm-scale ultramylonite bands, where solid-state reactions produced very fine grained polymineralic aggregates. Except for these latest stages of deformation, strain localization does not result from the microstructural evolution; the grain size decrease is a consequence of the need to deform a rock volume whose strength continuously increases because of decreasing temperature conditions. Strain localization in the intermediate levels thus essentially results from the more localizing behavior of both the deep, partially molten, and shallow parts of this extensional shear zone distribution.
ISSN: 1525-2027

hal-00644844
https://hal.archives-ouvertes.fr/hal-00644844
DOI : 10.1029/2011GC003627

Éditeur(s) : HAL CCSD Wiley
Résumé : International audience
Emerging high data rate wireless communication systems, currently under development, will operate at millimeter waves (MMW) and specifically in the 60 GHz band for broadband short-range communications. The aim of this study was to investigate potential effects of MMW radiation on the cellular endoplasmic reticulum (ER) stress. Human skin cell lines were exposed at 60.4 GHz, with incident power densities (IPD) ranging between 1 and 20 mW/cm(2) . The upper IPD limits correspond to the ICNIRP local exposure limit for the general public. The expression of ER-stress sensors, namely BIP and ORP150, was then examined by real-time RT-PCR. Our experimental data demonstrated that MMW radiations do not change BIP or ORP150 mRNA basal levels, whatever the cell line, the exposure duration or the IPD level. Co-exposure to the well-known ER-stress inducer thapsigargin (TG) and MMW were then assessed. Our results show that MMW exposure at 20 mW/cm(2) inhibits TG-induced BIP and ORP150 over expression. Experimental controls showed that this inhibition is linked to the thermal effect resulting from the MMW exposure. Bioelectromagnetics. 35:444-451, 2014. © 2014 Wiley Periodicals, Inc.
ISSN: 0197-8462

hal-01063910
https://hal.archives-ouvertes.fr/hal-01063910
DOI : 10.1002/bem.21864
PUBMED : 25099539

Éditeur(s) : Pergamon-elsevier Science Ltd
Résumé : Shrimp farming in New Caledonia typically uses a flow-through system with water exchange rates as a tool to maintain optimum hydrological and biological parameters for the crop. Moreover, the effluent shows hydrobiological characteristics (minerals, phytoplankton biomass and organic matter) significantly higher than that of the receiving environment. Separate surveys were carried out in a bay (CH Bay) with a medium-size intensive farm (30 ha) (PO) and in a mangrove-lined creek (TE Creek) near a larger semi-intensive farm (133 ha) (SO). Net loads of nitrogen exported from the semi-intensive farm and the intensive farm amounted to 0.68 and 1.36 kg ha(-1) day(-1), respectively. At CH Bay, discharge effects were spatially limited and clearly restricted to periods of effluent release. The high residence time at site TE favoured the installation of a feedback system in which organic matter was not exported. Mineralization of organic matter led to the release of nutrients, which in turn, caused in an increased eutrophication of this ecosystem. The study of the pico- and nanophytoplankton assemblages showed (i) a shift in composition from picophytoplankton to nanophytoplankton from offshore towards the coast and (ii) a shift within the picophytoplankton with the disappearance of Prochlorococcus and the increase of picoeucaryotes towards the shoreline. These community changes may partially be related to a nitrogen enrichment of the environment by shrimp farm discharges. Thus, in view of the recent addition of the New Caledonian lagoon to the UNESCO World Heritage list, the data presented here could be a first approach to quantify farm discharges and evaluate their impact on the lagoon. (C) 2010 Elsevier Ltd. All rights reserved.
Marine Pollution Bulletin (0025-326X) (Pergamon-elsevier Science Ltd), 2010 , Vol. 61 , N. 7-12 , P. 387-398

Droits : 2010 Elsevier Ltd All rights reserved.
http://archimer.ifremer.fr/doc/00014/12527/9882.pdf
DOI:10.1016/j.marpolbul.2010.07.005
http://archimer.ifremer.fr/doc/00014/12527/

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
Abstract View references (35)La0.6Sr0.4Co0.2Fe0.8O3-δ (LSCF) hollow fibres were prepared by a phase inversion/sintering method using polyetherimide as a binder. In order to overcome surface exchange kinetics limitation, LSCF hollow fibres were coated with ∼200nm palladium (Pd) nanoparticles. The O2 flux of best performing membranes increased by up to 350% in comparison to unmodified LSCF hollow fibres. Optimal enhancement was achieved with a single Pd coating. Additional coatings resulted in reduced O2 fluxes, thus counter acting the beneficial spill-over effect of the catalyst. Long term stability testing in atmospheric air at 850°C showed that a LSCF membrane modified with a single Pd coating continually outperformed a pure LSCF hollow fibre for over 400h, though the level of enhancement was reduced over time. A dramatic reduction in performance of more than 45% occurred within the first 24h of testing, which was attributed to the coalescence and aggregation of Pd catalyst particles to ∼1000nm size at the LSCF grain boundaries. This greatly reduced the available area for the oxygen species to spill-over onto the LSCF surface and thus reduced the overall O2 flux. © 2011 Elsevier B.V.
ISSN: 0376-7388

hal-01683196
https://hal.univ-antilles.fr/hal-01683196
DOI : 10.1016/j.memsci.2011.07.008

Éditeur(s) : Elsevier Science Bv
Résumé : Monitoring fish and underwater habitats, particularly in and around marine protected areas (MPAs) requires non-destructive observation methods. This is generally achieved by divers conducting underwater visual censuses (UVC), but video-based techniques are now being used more often to observe underwater macrofauna and habitats. A comparison of these two techniques is relevant with the development of high-definition (HD) video, which constitutes a substantial improvement over previously available video resolutions at limited extra cost. We conducted a paired observation experiment involving both HD video and UVC in an MPA located in the New Caledonian lagoon, which is a highly diversified coral reef ecosystem. We compared three techniques for counting fish along 50 m x 4 m delineated strip transects: UVC and two video techniques in which the diver used either a straight trajectory (I-type transect) or a browsing one (S-type transect). The results showed that the proportion of fish that were not identified up to the species level did not exceed 3.3% in video observations versus 1.7% in UVC. The abundance and species richness were larger in UVC than in videos, and S-type transects detected more individuals and species than I-type transects. The average abundance and species richness observed by UVC were 1094 individuals and 69.7 species per transect respectively. In comparison with UVC. I-type and S-type video transects detected on average 56% and 61% of the abundance and 85% and 77% of the species richness seen by UVC respectively. Our results showed that, in comparison to UVC data recorded in situ, the post field analysis of HD video images provided representative observations of fish abundance and species diversity, although fewer species and individuals were detected. The advantages and shortcomings of each observation technique for monitoring fish assemblages, particularly in an MPA are discussed. HD video appears to be a cost-effective technique in terms of the human resources and time needed for field implementation. Overall, this study suggests that HD video-based techniques constitute an interesting complement to UVC, or an alternative when these cannot be implemented. (C) 2010 Elsevier B.V. All rights reserved.
Fisheries Research (0165-7836) (Elsevier Science Bv), 2011-01 , Vol. 107 , N. 1-3 , P. 84-93

Droits : 2010 Elsevier B.V. All rights reserved.
http://archimer.ifremer.fr/doc/00031/14192/11470.pdf
DOI:10.1016/j.fishres.2010.10.011
http://archimer.ifremer.fr/doc/00031/14192/

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
A laser ablation ICP-MS U-Pb age of 17.84 +/- 0.12 Ma (late Burdigalian) was obtained from monazites separated from a leucocratic diatexite collected in close proximity to a small peridotite massif incorporated into the lower crustal sequence of the Edough Massif (north-eastern Algeria), a southern segment of the peri-Mediterranean Alpine Belt. Monazites extracted from a neighbouring deformed leucogranite intruding early Paleozoic phyllites yield a consistent age of 17.4 +/- 1.3 Ma. Zircons occurring in the same leucogranite, with magmatic characteristics, have an age of 308 +/- 7 Ma interpreted as dating magmatic crystallisation of the leucogranite and reflecting partial melting during the Hercynian orogeny. Low Th/U domains (Th/U<0.10) from the same grains substantiate recrystallisation during a younger metamorphic event whose upper age limit is 286 +/- 11 Ma. These results emphasize the polycyclic evolution of basement rocks preserved in the crystalline units of the western Mediterranean and indicate that part of their metamorphic features were inherited from older, Hercynian, events. Taken together with published Ar-Ar dates, the late Burdigalian age of monazites indicates a rapid cooling rate of c. 370 degrees C/Ma and is regarded as closely approximating the emplacement of the peridotites into the Hercynian basement. The monazite ages are significantly younger than those recorded for orogenic peridotites from the Betic-Rif oroctine and for the timing of lithospheric extension forming the Alboran sea. It is also younger than rifting and back-arc extension opening the Liguro-Provencal basin. The late Burdigalian age is interpreted as dating the incipient rifting event that opened the Algerian basin, which is consequently not a continuation of the Liguro-Provencal basin. At the scale of the western Mediterranean, these observations concur with current models supporting slab roll-back and an eastwards migration of extension in the western Mediterranean, but suggest that the Algerian basin opened as a result of torsion and stretching of the Thethyan slab due to its steepening under the Alboran microplate.
ISSN: 0009-2541

hal-00424511
https://hal.archives-ouvertes.fr/hal-00424511
DOI : 10.1016/j.chemgeo.2008.11.016

Éditeur(s) : Elsevier
Résumé : The "Summer Syndrome", a septicemic vibriosis caused by Vibrio nigripulchritudo, is responsible for one of the two main seasonal mortalities which affect shrimp aquaculture in New Caledonia. It was identified for the first time in December 1997 in an intensive shrimp farm (called farm DF) and has been enzootic ever since. The "Summer syndrome" affects shrimp during warm-season growout. Although the geographic area concerned is limited, it is a potential threat for the industry in that the disease could spread. Analysis of grow out data from 1991 to 2002 in this farm was carried out in order to characterize the disease and the environmental conditions in relation to mortality. Results of farm DF were compared to data from farms not affected by the disease (called farms HC). The "Summer syndrome" occurs during the warm season which is characterized by an increase in water temperature and sunny duration. This disease is characterized by simultaneously highest densities and weakest drying duration between crops in the farms studied. Between 1991 and 2002, the increase of feed input and nitrogen rate in feed has led to a significant increase of the growth rate over the years in farm DF. At the same time, water management has not changed and has induced an increase in environmental waste production. In consequence, an early eutrophication of water is observed, which is concomitant with the beginning of the mortality outbreaks. This could play a role by inducing directly or indirectly a stress for shrimp and/or a growth and/or virulence factors of the pathogen.
Aquaculture (0044-8486) (Elsevier), 2006-08 , Vol. 261 , N. 3 , P. 1039-1047

Droits : 2006 Elsevier
http://archimer.ifremer.fr/doc/2006/publication-1868.pdf
DOI:10.1016/j.aquaculture.2006.08.036
http://archimer.ifremer.fr/doc/00000/1868/

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
Xenoestrogens may persist in the environment by binding to sediments or suspended particulate matter serving as long-term reservoir and source of exposure, particularly for organisms living in or in contact with sediments. In this study, we present for the first time an effect-directed analysis (EDA) for identifying estrogenic compounds in a sediment sample using embryos of a transgenic reporter fish strain. In the tg(cyp19a1b-GFP) transgenic zebrafish strain, the expression of GFP (green fluorescent protein) in the brain is driven by an oestrogen responsive element in the promoter of the cyp19a1b (aromatase) gene. The selected sediment sample of the Czech river Bilina had already been analysed in a previous EDA using the yeast oestrogen screening assay and had revealed fractions containing estrogenic compounds. When normal phase HPLC (high performance liquid chromatography) fractionation was used for the separation of the sediment sample, the biotest with transgenic fish embryos revealed two estrogenic fractions. Chemical analysis of candidate compounds in these sediment fractions suggested alkylphenols and estrone as candidate compounds responsible for the observed estrogenic effect. Alkylphenol concentrations could partially explain the estrogenicity of the fractions. However, xenoestrogens below the analytical detection limit or non-targeted estrogenic compounds have probably also contributed to the sample's estrogenic potency. The results indicated the suitability of the tg(cyp19a1b-GFP) fish embryo for an integrated chemical-biological analysis of estrogenic effects.
ISSN: 0166-445X

hal-01072210
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01072210
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01072210/document
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01072210/file/Effect-directed_analysis_for_estrogenic_compounds-final.pdf
DOI : 10.1016/j.aquatox.2014.05.016

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
The thermal evolution of sediments in the shallowest part of sedimentary basins is challenging to investigate as most of the geothermometers are at their application limits. This is typically the case of the Callovian-Oxfordian claystones at the eastern border of the Paris Basin. A recent 2000 m deep well penetrated the entire Jurassic and Triassic sedimentary series and permitted coring of sediments never reached by previous drilling in this part of the basin. Thanks to the use of several independent geothermometers (apatite fission track thermochronology, fluid inclusion microthermometry, clay mineralogy and sedimentary organic matter evolution) the burial history of the Mesozoic series has been reconstructed, modeled and calibrated using kinetic algorithms relevant to the various paleothermometers used. In addition to these conventional methods, an innovative approach was developed using the temperature-dependence of the magnetic mineral assemblage within clay-rich sediments ("MagEval"). Thermal modeling indicates that the Callovian-Oxfordian and the Lower Triassic experienced maximum burial temperatures of 50 +/- 5 C-circle and 90 +/- 10 C-circle respectively, i.e., about 25 C higher than present-day. This temperature offset implies the erosion of several hundred meters of sediments which, depending on the thermal flux and conductivity considered, most likely constituted Upper Cretaceous chalk deposits. Falling sea level resulted in the exposure and subsequent dismantling of the chalk cover at the beginning of Cenozoic times. The eastern border of the basin was then subjected to slow erosion and discrete tectonic deformation.
ISSN: 0264-8172

hal-01313142
https://hal.archives-ouvertes.fr/hal-01313142
DOI : 10.1016/j.marpetgeo.2013.08.019

Éditeur(s) : HAL CCSD American Geophysical Union
Résumé : International audience
The 856 A.D. Qumis earthquake (M7.9) is the most destructive earthquake to have occurred in Iran, killing more than 200,000 people and destroying the cities of Damghan and the old Parthian capital of Shahr-i Qumis (Hecatompylos). This study combines evidence of historical seismicity with observations of the geomorphology and paleoseismology to provide the first detailed description of active faulting in the Damghan region of the east Alborz mountains, Iran. Regional left-lateral shear is accommodated on the Astaneh, Damghan, and North Damghan faults. Quaternary alluvial fans have been displaced along the Astaneh fault, with 15–20 m stream offsets recording the cumulative displacement over the last two to five earthquakes. A paleoseismology study from a single trench along a 5–10 km segment of the Astaneh fault reveals a rupture prior to 1300 A.D. and significantly later than 600 B.C. Despite the limitations of a single trench in documenting the spatial and temporal evolution of the fault over the late Quaternary, we are nevertheless able to bracket the last event to a time period consistent with the 856 A.D. earthquake. Two older earthquakes were also identified during the Holocene occurring between 600 B.C. and 4600 B.C. and between 4600 B.C. and 9600 B.C. The location of our trench within a bend on the Astaneh fault, which could act as a barrier to rupture propagation, means the three earthquakes recovered from our trench over the Holocene may represent a minimum. Further trenching will reveal how the Astaneh fault ruptures over repeated earthquakes and, consequently, the magnitude and extent of slip during the 856 A.D. earthquake.
ISSN: 0148-0227

hal-00551330
https://hal.archives-ouvertes.fr/hal-00551330
https://hal.archives-ouvertes.fr/hal-00551330v2/document
https://hal.archives-ouvertes.fr/hal-00551330/file/Hollingsworth2010.pdf
DOI : 10.1029/2009JB007185

Éditeur(s) : HAL CCSD
Résumé : International audience
BACKGROUND: Semi Volatile Organic Compounds (SVOCs) are contaminants commonly found in dwellings as a result of their use as plasticizers, flame retardants, or pesticides in building materials and consumer products. Many SVOCs are suspected of being neurotoxic, based on mammal experimentation (impairment of locomotor activity, spatial learning/memory or behavioral changes), raising the question of cumulative risk assessment. The aim of this work is to estimate the relative toxicity of such SVOCs, based on neuronal death. METHOD: SVOCs fulfilling the following conditions were included: detection frequency >10% in dwellings, availability of data on effects or mechanism of action for neurotoxicity, and availability of dose-response relationships based on cell viability assays as a proxy of neuronal death. Benchmark concentration values (BMC) were estimated using a Hill model, and compared to assess relative toxicity. RESULTS: Of the 58 SVOCs selected, 28 were suspected of being neurotoxic in mammals, and 21 have been documented as inducing a decrease in cell viability in vitro. 13 have at least one dose-response relationship that can be used to derive a BMC based on a 10% fall in neuronal viability. Based on this in vitro endpoint, PCB-153 appeared to be the most toxic compound, having the lowest BMC10 (0.072μM) and diazinon the least toxic compound, having the highest BMC10 (94.35μM). We showed that experimental designs (in particular choice of cell lines) had a significant influence on BMC calculation. CONCLUSION: For the first time, the relative in vitro toxicity of 13 indoor contaminants belonging to different chemical families has been assessed on the basis of neuronal cell viability. Lack of comparable toxicity datasets limits the number of SVOCs that can be included. More standardized protocols in terms of cell lines, species and exposure duration should be developed with a view to cumulative risk assessment.
Toxicology Letters

hal-01579605
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01579605
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01579605/document
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01579605/file/Fournier%20et%20al.%20-%20Relative%20toxicity%20for%20indoor%20semi%20volatile%20organic.pdf
DOI : 10.1016/j.toxlet.2017.07.875

Résumé : Évoquer la place des libres de couleur en Martinique des origines à 1815, c'est évoqué un curieux paradoxe. Afin d'appréhender ce dernier et aborder la position des libres de couleur dans la société, il a fallu se pencher sur le processus de formation de ce groupe de 1635 à la veille de la Révolution française, en mettant en lumière l'origine de celui-ci, le statut, la condition des personnes, la répartition géographique, la situation socioéconomique et les réseaux de sociabilité qu'ils utilisent dans la société. L'abord de ce processus ne pouvait se faire sans la prise en compte de la politique menée par l'administration envers l'affranchissement. L'utilisation des registres paroissiaux (puis de l'état civil) et du notariat a permis la confrontation entre la théorie (le droit colonial), et, la pratique quotidienne. Il a fallu ensuite mettre en évidence dans un second temps comment, malgré la Révolution française et de ses idéaux, de son impact en Martinique, la ségrégation perdure à l'encontre du groupe des libres de couleur et confirme l'entre-deux de celui-ci dans la société, en dépit de son accroissement numérique (via l'affranchissement principalement) et économique, et ce, jusqu'au début de la Restauration. La politique coloniale menée par les différentes administrations qui se succèdent et les troubles qui perturbent l'ordre établi ont favorisé la compréhension du phénomène. Si, les libres de couleur furent assimilés dès 1685 aux sujets naturels du royaume de France, ils ne purent pourtant exercer comme les Blancs, certaines charges publiques, certaines professions libérales, certains emplois dans la milice (officiers). Cependant, certains d'entre eux réussirent à se hisser économiquement au niveau des négociants blancs avant 1815. Néanmoins, ils demeurèrent cantonnés dans une place mitoyenne entre Blancs et esclaves, une "zone tampon", un entre-deux discriminatoire et ségrégatif. Ces libres de couleur qui étaient aussi bien des noirs que des métis furent rejetés par les Blancs qu'ils souhaitaient égaler et méprisaient en général les esclaves alors qu'ils étaient souvent liés à eux par un ancêtre noir. Comme les Blancs, ils possédaient des esclaves, des terres et des maisons. Pourtant, leur situation dans la société fut très paradoxale.
To evoke the place of free coloureds in Martinic from the earliest times to 1815, it is evoked a curious paradox. In order to apprehend this last and to tackle free coloureds position in the society, it had to look into the process of development of this group from 1635 to the day before french revolution. The access of this process could not become without taking into consideration of the political controlled by the administration on emancipation. The utilization of parish registers (then registers of births, marriages and deaths) and deeds executed by a notary permitted confrontation between the theory (the colonial right) and the daily practical. It had to show how in spite of french revolution and these ideals, and this impact in Martinic, the segregation be continued against free coloureds group and confirmed space in between of this group in the society in spite of these numerical and economic growth (by way of emancipation principally), and those, as far as the beginning of the Restoration. The colonial political controlled by different administrations who followed one another and unrest who perturbed etablished order assisted the comprehension of this phenomenon. If free coloureds were assimilated since 1685 to natural subjects of french kingdom with the same rights, privileges and immunities, they did not exercise as whites some public responsabilities and offices, some liberal trades, some positions in militia (officers). Before the end of observation period (1815), some people were succeded to hoist themselves economically on a level with whites wholesalers. In spite of that, they were limited in a intermediate place between whites and slaves, a "buffer zone". Free coloureds who were as well as blacks than halfcastes have been rejected by whites that they would wish to equal and despised in general slaves even when they had common interests (a mother or a sister in slavery). As whites, they possessed slaves, estates and houses. However, their situation was so paradoxical in the colonial society.

http://www.theses.fr/2011AGUY0395/document

Éditeur(s) : Elsevier
Résumé : The Summer Syndrome is a new shrimp disease that has been affecting a shrimp growout farm in New Caledonia since end of 1997. It was recognized to be caused by a systemic vibriosis due to Vibrio nigripulchritudo. This new disease turned out almost immediately enzootic in the shrimp farm involved and has affected all its crops ever since. Since the year 2000, V. nigripulchritudo strains have been found in several shrimp farms, although Summer Syndrome is still limited to one particular area, affecting, since 2003, two adjoining farms. As part of a multidisciplinary research program, a high-frequency survey was carried out during the summer 2002-2003 in two shrimp farms: one affected farm and another one in which pathogenic strains could be isolated but without any disease event. It permitted a good description of V. nigripulchritudo dynamics in shrimp and the ecosystem in both farms. The study of virulence characteristics of some isolates showed that pathogenic and non-pathogenic strains occur in the shrimp farms environment and that both may be found at the same time in one farm. Our results strongly suggest a persistence of pathogenic strains in wet zones of the pond sediment at low concentrations between crops in the affected farm, and their development during the rearing cycle as a cause of shrimp infection.
Aquaculture (0044-8486) (Elsevier), 2006-03 , Vol. 253 , N. 1-4 , P. 105-113

Droits : 2005 Elsevier B.V. All rights reserved
http://archimer.ifremer.fr/doc/2006/publication-1110.pdf
DOI:10.1016/j.aquaculture.2005.07.031
http://archimer.ifremer.fr/doc/00000/1110/