Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
The Tso Morari serpentinites in the Ladakh area, northwest Himalaya, originated from the forearc mantle overlying the northward subducting Neo-Tethys lithosphere and the margin of the Indian continent. The serpentinites are characterized by high concentration of fluid-mobile elements (FME: As, Sb, B, Li, and U) compared to ophiolitic or abyssal serpentinites. The Pb isotopic compositions of serpentinites show influence of the subducted Indian continental lithosphere. Trace element concentrations of antigorite determined in situ with Laser Ablation High Resolution Inductively Coupled Mass Spectrometer (LA-HR-ICP-MS) show high contents of FME including Pb, in contrast to the spatially associated iron oxides. Rare earth elements (REE) and compatible elements, such as Sc and Co, remained immobile during the hydration, allowing the identification of the primary minerals (olivine or orthopyroxene) from which serpentine formed. Serpentinized olivine displays higher Sb and As concentrations (up to 1000 x PM) than serpentinized orthopyroxenes that are enriched in Pb, Cs and Li (2 to up to 10 x PM).;We propose that the observed FME distribution in two types of serpentine reflect the differential incorporation of FME during the downward movement of the serpentinite along the subduction plane. At temperature lower than 400 degrees C, at shallow depths, olivine is preferentially serpentinized and incorporates elements that are fluid soluble at low temperatures, such as Sb and As. Above 400 degrees C, orthopyroxene is hydrated and incorporates Pb, Cs, Li and possibly Ba. Boron and U are incorporated in both types of serpentine suggesting that they are released from slabs at temperatures around 300-400 degrees C. The serpentine acts as a sink for water, but also for FME and transports them to deeper and hotter levels in the mantle, down to the isotherm 600-650 degrees C where dehydration occurs.
ISSN: 0009-2541

hal-00475565
https://hal.archives-ouvertes.fr/hal-00475565
DOI : 10.1016/j.chemgeo.2009.10.002

Éditeur(s) : Université des Antilles Études caribéennes
Résumé : In this study, we propose to analyze the limits of mass tourism in the French Antilles, specifically the decline of tourism, economic limits, and ecological degradation). The recognition of these limits is overdue, and signals a need to define another model for tourism development.The popular coastal sector in the south of Martinique has been subject new regulations to protect marine resources. These regulations require the development of new practices and a greater level of awareness for tourists, for example, around coral reefs and mangroves. Ecotourism programs aim to demonstrate to visitors the forests rich natural resources and biodiversity in general. It also features the inclusion of small rural businesses that benefit from additional sources of revenue as a result of ecotourism.The situation in the French Antilles is complex: Urbanization is fraught with serious consequences for the coastline. Tourism products currently being marketed on the island are not competitive (particularly against the political dynamics of the neighbouring island of Dominica). Ecotourism and sustainable tourism are just beginning to develop in such destinations, where tourism has been declining in the last ten years. The situation of the French Antilles is paradoxical in a region that generally has a very favourable tourism. Assessing these limits through the scope of ecotourism helps to highlight the causes of these difficulties and to adapting to new tourism practices.
Dans le cadre de cette étude, l’accent est mis sur les limites du tourisme de masse dans les Antilles françaises (dépréciation du tourisme, les contraintes économiques et les nuisances écologiques). La reconnaissance de ces limites est à l'origine de la prise de conscience tardive de la nécessité de définir un autre modèle de développement touristique.Dans le sud de la Martinique, le secteur le plus populaire du littoral, de nouvelles règlementations sont mises en place pour protéger les ressources marines. Cela nécessite le développement de nouvelles pratiques et de sensibilisation des touristes notamment autour des récifs coralliens et les mangroves. Les programmes autour de l'écotourisme visent également à montrer aux visiteurs la richesse des ressources forestières et de la biodiversité en général. Il comprend également les petites entreprises rurales qui reçoivent de nouveaux revenus grâce au tourisme.La situation est complexe dans les Antilles françaises: l'urbanisation est lourde de conséquences importantes sur la côte. Les produits touristiques commercialisés actuellement ne sont pas compétitifs (notamment contre la dynamique politique de l'île voisine de la Dominique). L'écotourisme et le tourisme durable commencent tout juste à se développer dans ces destinations où le tourisme classique est en difficulté depuis une dizaine d’années ; situation assez paradoxale au regard du dynamisme de ce secteur d’activité dans la région.
En el contexto de este estudio, nos proponemos analizar los límites del turismo de masas en las Antillas Francesas (depreciación del turismo, las limitaciones económicas, ecológicas y las molestias). Este reconocimiento de esos límites está en el origen de la conciencia tardía de la necesidad de definir otro modelo de desarrollo turístico.En el sector costero de la más popular, como en el sur de Martinica, se pone en la normativa nuevo lugar para proteger los recursos marinos. Esto requiere el desarrollo de nuevas prácticas y la sensibilización de los turistas, por ejemplo, alrededor de los arrecifes de coral y los manglares.Programas en torno al ecoturismo también tienen como objetivo dar al visitante la riqueza de los recursos forestales y la biodiversidad en general. También incluye las pequeñas empresas rurales que reciben los nuevos ingresos a través del turismo.Pero la situación es compleja en las Antillas francesas: la urbanización está llena de importantes consecuencias para la costa. Productos turísticos que se comercializan actualmente no son competitivos (en particular, contra la dinámica política de la cercana isla de Dominica). Ecoturismo y desarrollo sostenible están empezando a desarrollar en este destino turístico, donde el turismo está en problemas en los últimos diez años.Esta situación es bastante paradójico en un turismo regional muy favorable. Sin lugar a dudas, pensando en el ecoturismo contribuye a identificar los destinos de estos retrasos y dificultades para adaptarse a nuevas prácticas de turismo.
Martinique

Droits : info:eu-repo/semantics/openAccess
urn:doi:10.4000/etudescaribeennes.5262
http://journals.openedition.org/etudescaribeennes/5262

Éditeur(s) : HAL CCSD American Geophysical Union
Résumé : During the 2003 summer monsoon, the Hi-CLIMB seismological stations deployed across the Himalayan Range detected bursts of high-frequency seismic noise that lasted several hours to days. On the basis of the cross correlation of seismic envelopes recorded at 11 stations, we show that the largest transient event on 15 August was located nearby a village partially destroyed on that day by a devastating debris flow. This consistency in both space and time suggests that high-frequency seismic noise analysis can be used to monitor debris flow generation as well as the evacuation of the sediment. A systematic study of one year of seismic noise, focusing on the detection of similar events, provides information on the spatial and temporal occurrence of mass movements at the front of the Himalayas. With a 50% probability of occurrence of a daily event, a total of 46 debris flows are seismically detected. Most of them were generated in regions of steep slopes, large gullies, and loose soils during the 2003 summer monsoon storms. These events are compared to local meteorological data to determine rainfall thresholds for slope failures, including the cumulative rainfall needed to bring the soil moisture content to failure capacity. The inferred thresholds are consistent with previous estimates deduced from soil studies as well as sediment supply investigations in the area. These results point out the potential of using seismic noise as a dedicated tool for monitoring the spatiotemporal occurrence of landslides and debris flows on a regional scale.
ISSN: 0148-0227

hal-00464177
https://hal.archives-ouvertes.fr/hal-00464177
DOI : 10.1029/2008JF001198

Éditeur(s) : HAL CCSD American Geophysical Union
Résumé : Results are reported for an acidic water flow-through experiment conducted in a fractured argillaceous limestone sample (73% carbonates). The change in fracture geometry and related parameters is reported for six data sets obtained from synchrotron X-ray microtomography experiments. High-resolution three-dimensional images of the sample allowed quantification of the changes in fracture morphology at a spatial resolution of 6 ;μm. Mineral mass loss and permeability changes in the sample were also determined. Several physico-chemical phenomena were identified during the experiment. Initial smooth fracture surfaces evolved rapidly toward rough surfaces with uneven clay coverage due to the preferential dissolution of carbonate minerals compared to clay minerals whose dissolution rate is about 106 slower. A microporous clay coating progressively developed at the fluid-rock interface during heterogeneous dissolution of the fracture, while the global dissolution rate of the fracture walls exponentially decreased. The increase in surface roughness and the presumed reorganization of clays caused a progressive reduction in permeability. During the last flow-through stage, a large decrease in sample permeability was attributed to the large removal of clay particles; this process was responsible for a dramatic collapse of the fracture walls near the sample inlet and led to the development of preferential flow pathways. The development of the clay coating also acted as a barrier to flow and mass transfer between calcite grains and bulk solution and affected transport processes within the fracture
ISSN: 0043-1397

hal-00405333
https://hal.archives-ouvertes.fr/hal-00405333
DOI : 10.1029/2006WR005379

Éditeur(s) : Elsevier
Résumé : The distribution and speciation of mercury (Hg) in the water column, the inputs (wet deposition and tributaries) and the outputs (atmospheric evasion and outlet) of an artificial partially anoxic tropical lake (Petit-Sa-Lit reservoir, French Guiana) were investigated oil a seasonal basis in order to appraise the cycling and transformations of this metal. The total mercury (HgT) concentrations in the oxygenated epilimnetic waters averaged 5 +/- 3 pmol L-1 in the unfiltered samples (HgTUNF) and 4 +/- 2 pmol L-1 in the dissolved (HgTD) phase (< 0.45 mu m). On average, the monomethylmercury (MMHg) constituted 8%, 40%, and 18% of the HgT in the dissolved phase, tile particulate suspended matter and in tile unfiltered samples, respectively. Covariant elevated concentrations of particulate MMHg and chlorophyll a in the epilimnion suggest that phytoplankton is ail active component for the MMHg transfer in tile lake. In the anoxic hypolimnion the HgTUNF averages 13 +/- 6 pmol L-1 and tile HgTD 8 +/- 4 pmol L-1. The averages of MMHgP and MMHgD in hypolimnetic waters were two and three times the corresponding values of the epilimnion, 170 +/- 90 pmol g(-1) and 0.9 +/- 0.5 pmol L-1, respectively. In the long dry and wet seasons, at the flooded forest and upstream dam sampling stations, the vertical profiles of MMHgD concentrations accounted for two distinct maxima: one just below the oxycline and the other near the benthic interface. Direct wet atmospheric deposition accounted for 14 moles yr(-1) HgTUNF, with 0.7 moles yr(-1) as MMHgUNF, while circa 76 moles yr(-1) of HgTUNF, with 4.7 moles yr(-1) as MMHgUNF, coming from tributaries. Circa 78 moles (similar to 17% as MMHg) are annually exported through tile dam, while 23 moles yr(-1) of Hg-0 evolve in the atmosphere. A mass balance calculation suggests that the endogenic production of MMHgUNF attained 8.1 moles yr(-1), corresponding to a methylation rate of 0.06% d(-1). As a result, tile Petit-Saut reservoir is a large man-made reactor that has extensively altered mercury speciation in favor of methylated species.
Applied Geochemistry (0883-2927) (Elsevier), 2008-05 , Vol. 23 , N. 5 , P. 1101-1126

Droits : 2008 Elsevier Ltd All rights reserved.
http://archimer.ifremer.fr/doc/2008/publication-4198.pdf
DOI:10.1016/j.apgeochem.2007.11.006
http://archimer.ifremer.fr/doc/00000/4198/

Éditeur(s) : HAL CCSD Wiley
Résumé : International audience
BACKGROUND: Recent studies suggest that a Mediterranean dietary pattern during pregnancy may influence pregnancy outcomes. The aim of this study was to evaluate the effect of adherence to a Mediterranean diet (MD) during pregnancy on fetal growth restriction (FGR) and preterm delivery (PTD) in a French Caribbean island where the population is largely of African descent and presents dietary patterns similar to MD. METHODS: Using data from the TIMOUN Mother-Child Cohort Study conducted in Guadeloupe (French West Indies) between 2004 and 2007, we analysed data for 728 pregnant women who delivered liveborn singletons without any major congenital malformations. Degree of adherence to MD during pregnancy was evaluated with a semi-quantitative food frequency questionnaire based on nine dietary criteria. Multiple logistic regression models were used to analyse birth outcomes while taking potential confounders into account. RESULTS: Overall there was no association between MD adherence during pregnancy and the risk of PTD or FGR. However, pre-pregnancy body mass index was a strong effect modifier, and MD adherence was associated with a decreased risk of PTD specifically in overweight and obese women (adjusted odds ratio 0.7, 95% confidence interval 0.6, 0.9) (P heterogeneity <0.01). CONCLUSIONS: These results suggest that Caribbean diet during pregnancy may carry some benefits of MD and may contribute to reduce the risk of PTD in overweight and obese pregnant women.
ISSN: 0269-5022

hal-00988172
https://hal-univ-rennes1.archives-ouvertes.fr/hal-00988172
DOI : 10.1111/ppe.12113
PUBMED : 24754337

Éditeur(s) : Elsevier
Résumé : The French Guiana transform margin and Demerara abyssal plain have been recently surveyed in the framework of the EXTRAPLAC French Program of extension of the continental shelf (Guyaplac survey, Ifremer-IFP-SHOM-IPEV). Based on the interpretation of some of the data collected during the Guyaplac survey (Simrad-EM12 multibeam bathymetric data, backscatter imagery, and 3.5 kHz profiles), the area can be divided into three morphostructural domains. (1) The western Guiana margin, including a part of the Demerara plateau, an important bathymetric relief prolonging the continental platform off Guiana and Surinam. This domain is bounded by (1a) the NWSE trending northern border of the Demerara plateau which appears quite steep and corresponds to a transform segment of the margin, (1b) the N-S eastern border of the Demerara plateau which corresponds to a divergent segment of the margin. The Demerara plateau shows a segmented morphology, low slope gradients, and a very rough surface (ripples perpendicular to the slope direction). NNW-SSE structural steps seem to correspond to collapses of 100 km long blocs towards the east. Slumps initiate along these directions. The observed rough bathymetry seems to be related to creeping processes. At a greater scale (seismic data), this part of the margin has been totally destabilized (numerous imbricate transparent masses rooted at about 0.5 s.t.w.t.t. below seafloor). The NW-SE trending northern border of the Demerara plateau corresponds to a cliff-like continental slope, probably slightly smoother than other transform margins (Ghana/cote d'Ivoire margin). The N-S eastern border of Demerara plateau is characterized by numerous small-scale imbricate slumps. Some of these failures seem to be emplaced in the prolongation of the NNW-SSE structural steps identified on the Demerara plateau. (2) The eastern Guiana margin corresponds to a NW-SE oriented gullied transform margin segment. The associated continental slope is very steep and characterized by numerous imbricate slumps and related debris flows. Some undulated masses, probably corresponding to creeping sediments or to older mass-wasting events are still imprinted on bathymetry. This transform margin segment is nearly entirely destabilized and eroded. (3) The Demerara abyssal plain. This domain is characterized eastwards by channels belonging to the Amazon turbidite system and westwards, at the foot of Demerara continental slope, by sediment waves probably created by contour currents. To conclude, it seems that there is a strong relationship between the structure (transform and divergent segments) and the emplacement of recurrent slope instabilities. These are probably related to the steepness of the slopes but also to subsidence histories generating in some cases huge deep-seated collapses of the whole margin. Fluid ascents are common everywhere in the area, probably enhancing slope instability. Their origin is not constrained but the black shales or Cretaceous organic-rich layers could be good candidates.
Marine and Petroleum Geology (0264-8172) (Elsevier), 2009-05 , Vol. 26 , N. 5 , P. 711-723

Droits : 2008 Elsevier Ltd All rights reserved.
http://archimer.ifremer.fr/doc/2009/publication-6856.pdf
DOI:10.1016/j.marpetgeo.2008.02.010
http://archimer.ifremer.fr/doc/00000/6856/

Éditeur(s) : Université des Antilles Études caribéennes
Résumé : Depuis le xviie siècle, le canal du Midi connaît des conflits d’usage et des paysages forts différents. Actuellement, les Voies Navigables de France (VNF) comme la population locale et les touristes se confrontent à une crise paysagère et environnementale majeure. La disparition des platanes centenaires à cause du champignon et de l’épidémie du chancre coloré est inéluctable. Cette crise bouleverse les niveaux d’information et de perception d’un espace touristique de première importance pour la France avec une inscription au patrimoine mondial de l’Unesco en 1996. Les arbres sont un marqueur d’une identité paysagère et de représentations touristiques très fortes. À partir d’une recherche archivistique inédite portant sur l’évolution du paysage et de l’action des acteurs, couplée à une enquête de terrain entre 2008 et 2013 sur le comportement des touristes et des promeneurs, nos résultats montrent que l’action de protection et de conservation de ce paysage rentrent dans une alliance renouvelée entre le tourisme de masse et le tourisme responsable, ils en deviennent interdépendants. La communication et la pédagogie environnementale auprès du grand public sur le degré de nature de ce site rentrent aussi dans une action à son tour résiliente et de développement durable, les ambivalences des comportements des usagers dans leur vision d’un site touristique hybride s’observent.
Since the seventeenth century, the canal du Midi known conflicts of use and a variety of landscapes. Currently, Waterways of France (VNF) as the local population and tourists are confronted with a major landscape and environmental crisis. The disappearance of the old plane because of the fungus and the epidemic of colored canker is inevitable. This crisis disrupts levels of information and perception of a tourist area of prime importance for France with an inscription on the World Heritage by UNESCO in 1996. Trees are a marker of landscape identity and tourist representations very strong. From unprecedented archival research on the changing landscape and action actors, coupled with fieldwork between 2008 and 2013 on the behavior of tourists and walkers, our results show that the action of protection and conservation of the landscape fit into a renewed relationship between mass tourism and alternative tourism alliance, they become interdependent. Communication and environmental education to the public on the state of nature of this site are also included in an action to turn its resilient and sustainable development, the ambivalences of user behavior in their vision of a hybrid attraction are observed.
Desde el siglo XVII, el canal du Midi conocido conflictos de usar y varios paisajes. Actualmente, Vías Navegables de Francia (VNF) como la población local y los turistas se enfrentan a una crisis ambiental y paisaje. La desaparición de los plátanos por el champiñón y la epidemia del cancro colorido es inevitable. Esta crisis altera los niveles de información y la percepción de una zona turística de gran importancia para Francia con una inscripción en el Patrimonio de la Humanidad por la UNESCO en 1996. Los árboles son un marcador de la identidad del paisaje y representaciones turísticas muy fuertes. De investigación de archivo original sobre la evolución del paisaje y la acción de los actores, junto con el trabajo de campo entre 2008 y 2013 en el comportamiento de los turistas y caminantes locales, nuestros resultados muestran que la acción de protección y conservación de la forma del paisaje en una renovada relación y la alianza entre el turismo de masas y el turismo alternativo, se vuelven interdependientes. Comunicación y educación ambiental al público sobre el estado de la naturaleza de este sitio se incluyen en una acción para activar su desarrollo resiliente y sostenible, las ambivalencias de comportamiento de los usuarios en su visión de un sitio turístico híbrido se observan.
France
Canal du Midi

Droits : info:eu-repo/semantics/openAccess
urn:doi:10.4000/etudescaribeennes.7566
http://journals.openedition.org/etudescaribeennes/7566

Éditeur(s) : HAL CCSD Springer Verlag
Résumé : International audience
Fish mucus has important biological and ecologicalroles such as defense against fish pathogens andchemical mediation among several species. A non-targetedliquid chromatography–mass spectrometry metabolomicapproach was developed to study gill mucus of eight butterflyfishspecies in Moorea (French Polynesia), and theinfluence of several fish traits (geographic site and reefhabitat, species taxonomy, phylogeny, diet and parasitismlevels) on the metabolic variability was investigated. Abiphasic extraction yielding two fractions (polar and apolar)was used. Fish diet (obligate corallivorous, facultativecorallivorous or omnivorous) arose as the main driver ofthe metabolic differences in the gill mucus in both fractions,accounting for 23% of the observed metabolic variabilityin the apolar fraction and 13% in the polar fraction.A partial least squares discriminant analysis allowed us toidentify the metabolites (variable important in projection,VIP) driving the differences between fish with differentdiets (obligate corallivores, facultative corallivores andomnivorous). Using accurate mass data and fragmentationdata, we identified some of these VIP as glycerophosphocholines,ceramides and fatty acids. Level of monogeneangill parasites was the second most important factor shapingthe gill mucus metabolome, and it explained 10% of themetabolic variability in the polar fraction and 5% in theapolar fraction. A multiple regression tree revealed that themetabolic variability due to parasitism in the polar fractionwas mainly due to differences between non-parasitized andparasitized fish. Phylogeny and butterflyfish species werefactors contributing significantly to the metabolic variabilityof the apolar fraction (10 and 3%, respectively) buthad a less pronounced effect in the polar fraction. Finally,geographic site and reef habitat of butterflyfish species didnot influence the gill mucus metabolome of butterflyfishes.
ISSN: 0722-4028

hal-01563312
https://hal-univ-perp.archives-ouvertes.fr/hal-01563312
DOI : 10.1007/s00338-017-1554-0

Résumé : This report presents recent data on chemical contaminants in coastal and transition water bodies of Adour-Garonne district, acquired as part of the WFD (water measurements in 2009) and network ROCCH (measures in sediments in 1999 and 2008 and in shellfish each year between 2008 and 2010). It should be noted that only environmental quality standards exist for water, and in the absence of sediment and biota EQS, it is not possible to use these data to determine the chemical quality of water bodies. However, when other types of reference values are available (produced by OSPAR for example), they are used to argue the status of water bodies in support of the data obtained on the water under the control WFD monitoring.
Ce rapport présente les données récentes sur les contaminants chimiques dans les masses d’eaux côtières et de transition du district Adour-Garonne, acquises dans le cadre de la DCE (mesures dans l’eau en 2009) et du réseau ROCCH (mesures dans les sédiments en 1999 et 2008 et dans les mollusques, chaque année entre 2008 et 2010). Il est à noter que seules des normes de qualité environnementales existent pour l’eau, et qu’en l’absence de NQE biote et sédiment, il n’est pas possible d’utiliser ces données pour statuer sur la qualité chimique d’une masse d’eau. Néanmoins, lorsque d’autres types de valeurs de référence sont disponibles (produites dans le cadre d’OSPAR par exemple), elles sont utilisées pour argumenter le statut des masses d’eau, en appui des données obtenues sur l’eau dans le cadre du contrôle de surveillance DCE.

Droits : 2012 Ifremer
http://archimer.ifremer.fr/doc/00073/18459/16008.pdf
http://archimer.ifremer.fr/doc/00073/18459/

Éditeur(s) : HAL CCSD Université des Antilles
Résumé : International audience
The Caribbean Sea is emblematic of the cruise, it is known for its international routes, scenic postcards touting the charms of the region. The analysis of the cruise industry will highlight some limits and contradictions of current development patterns. The product "cruise" has evolved considerably. It’s now the cruise ship itself (temple of consumption and enclave floating) that became the object of the Cruise, the “Destination” of the cruise line.The cruise is part of mass tourism. It’s characterized by its huge boats, rationalization and cost optimization in the context of a market increasingly globalized capital. All data that must be analyzed to understand recent developments in the cruise and repeated challenges to the host territories.
El Mar Caribe es un emblema de la travesía. Esta conocido por sus rutas internacionales, postales escénicas explicando en detalle los encantos de la región. El análisis de la industria de los cruceros pondrán de relieve algunos límites y contradicciones de los patrones actuales de desarrollo. El producto "crucero" ha evolucionado considerablemente. Ahora es el crucero en sí (el templo del consumo y el enclave flotante) que se convirtió en el objeto del Crucero, el Destino "de la línea de cruceros. El crucero es parte del turismo de masas. Se caracteriza por sus grandes barcos, la racionalización y optimización de costes en el contexto de un mercado de capitales cada vez más globalizado. Todos los datos que se deben analizar para comprender la evolución reciente en el crucero y constantes desafíos a los territorios de acogida.
La mer des Caraïbes est un espace emblématique de la croisière. Au-delà de la réputation mondiale de ses destinations, des cartes postales qui vantent les charmes de la région, l’analyse de l’industrie de la croisière permet de souligner certaines limites et contradictions des modalités de développement actuelles. Le produit « croisière » a considérablement évolué : désormais c’est le paquebot en lui-même (temple de la consommation et enclave flottante) qui est devenu la destination du croisiériste. Ouverture au tourisme de masse, gigantisme des bateaux, rationalisation et optimisation des coûts dans le cadre d’un marché de plus en plus globalisé et capitalistique sont autant de données qui doivent être analysées pour comprendre l’évolution récente de la croisière et les défis renouvelés pour les territoires d’accueil.
ISSN: 1779-0980

hal-01624772
https://hal.archives-ouvertes.fr/hal-01624772
DOI : 10.4000/etudescaribeennes.3843

Éditeur(s) : HAL CCSD Station Biologique
Résumé : International audience
From fish samplings (rotenone: 6 February 2002 & 13 May 2003; boxtraps: January 2008 to July 2009) in amangrove lagoon, the demographic structure, reproductive period and diet of Lophogobius cyprinoides were studied.Individual fish were measured (< 1 mm), weighed (± 0.01 g), and sexed by observing the urogenital papilla, sex-ratios andtotal length (TL)-standard length and length-mass relationships were calculated. Five individuals per size class (2 mm) wereused to study sexual maturity by macroscopic observation of gonad structure with a sexual maturity scale, and diet byqualitative and quantitative examination of digestive tract contents and calculation of the following indices: levels offullness and vacuity; occurrence, number, and point frequencies of various food items, and quality of nutrition. Growth isisometric and sexual dimorphism in favor of males (78 vs. 64 mm), demographic structure (18 ≤ TL ≤ 78 mm) and conditionevolved over time, with a distinct femininization of the population. Sexual inversion appeared from 46 mm onward, andtotal masculinization at 72 mm. Protogynous hermaphrodism is advantageous in a sedentary, subcryptobenthic species thatis reproductively active almost throughout the year. The species has an omnivorous diet specialized in copepods and plants
ISSN: 0007-9723

hal-00746079
https://hal.univ-antilles.fr/hal-00746079

Éditeur(s) : HAL CCSD
Résumé : Karstic aquifers represent the most important fresh water reservoirs in many regions of the world like the Mediterranean Basin. However, because of complex processes of karstification, those aquifers are highly heterogeneous at all spatial scales and vulnerable to contamination. In this dissertation, we studied the potential of gravimetry and ambient seismic noise for hydrological modeling in karstic areas.The dolomitic area surrounding the “GEK” observatory in the Durzon catchment on the Larzac plateau, in France, is the preferred site for these studies. Inside the observatory, a superconducting gravimeter dedicated to hydrology has continuously measured gravity changes since 2011 with high precision, undertaken for the first time on a karst. From this gravity monitoring, we made conceptual hydrological models which laid the foundation of 1-D flow physical models. Indeed, gravimetry is an integrative hydro-geophysical method which allows 1) to consider the epikarst, locally heterogeneous as an equivalent tabular medium and 2) to define the types of transfer (fast & slow) occurring at the site. Especially, the lack of fast transfer through the GEK epikarst was precisely quantified for the first time at the field scale (~100m). Gravity-driven water mass balance with local meteorological data (evapotranspiration from a flux tower and precipitation) allowed setting the bottom outlet of the model to 1 mm.day-1. This flow has proved to be representative of the low-flow discharge at the only spring which represents all groundwater outflows from the catchment. This result supposes the homogeneity of the dolomitic epikarst almost at the basin scale. Model parameters were next calibrated using one year of ambient seismic noise monitored at two stations. Phase velocity changes obtained by cross-correlating the noise between 6 and 8 Hz were used as a ”timer” to follow the water infiltration between a depth of 30 and 60 meters. Thus, monitoring seismic velocity changes using ambient seismic noise demonstrates great potential for the study of deep and complex critical zones and could fill the instrumental gap currently existing in hydrology.Time-lapse gravity measurements with a spring-based portable gravimeter have also demonstrated the different behavior of two epikarsts and their variability at the scale of a few hundred meters. Monthly measurements around the observatory revealed the spatial homogeneity of this dolomitic epikarst: all the stations showed the same water storage changes. On the contrary, seasonal surface to depth gravity measurements along the underground passage of the Saint-Ferréol sinkhole, in limestone, have shown fast transfer and strong spatial variability of water storage. Lithology is then expected to play a part in the epikarst capacity to retain water. The precision needed to measure the weak hydrological induced signals during those surveys required robust methodology and an ambient temperature effect on measurements with spring-based gravimeter was observed in the field and quantified in the laboratory.
Les aquifères karstiques représentent des ressources en eau essentielles dans de nombreuses régions du monde comme le bassin Méditerranéen. Cependant, de par les processus complexes de karstification, ces aquifères sont hétérogènes à de nombreuses échelles et vulnérables. Dans cette thèse, nous étudions le potentiel de la gravimétrie et du bruit sismique ambiant pour la modélisation hydrologique en milieu karstique.Le site dolomitique de l’observatoire « GEK », sur le bassin du Durzon dans le Larzac, est le site d’étude privilégié de ces travaux. Dans l’observatoire, un gravimètre supraconducteur dédié à l’hydrologie mesure depuis 2011 les variations de gravité en continu et à une très haute précision, pour la première fois sur un karst. Des modèles hydrologiques conceptuels ont été réalisés à partir de cette surveillance gravimétrique et ont permis de poser les bases de modèles physiques d’écoulements 1-D. En effet la gravimétrie, intégratrice, permet 1) de considérer l’épikarst localement hétérogène comme un milieu tabulaire équivalent et 2) de définir les types de transfert à l’œuvre sur le site. En particulier, l’absence de transfert rapide dans l’épikarst a été quantifiée avec précision pour la première fois à l’échelle du terrain (~100m). A l’aide de données météorologiques locales, un bilan de masse précis a permis de définir le flux en limite inférieure du modèle à 1 mm.jour-1. Ce flux s’est montré représentatif du débit de basses-eaux de la source drainant l’ensemble du bassin. Ce résultat suppose une homogénéité de l’épikarst dolomitique quasiment à l’échelle du bassin. Les paramètres des modèles physiques ont ensuite pu être calibrés à l’aide d’un an d’intercorrélation du bruit sismique ambiant entre deux stations. Les variations de vitesses de phase obtenues entre 6 et 8Hz nous ont servi de « chronomètre » pour suivre l’infiltration entre 30 et 60m de profondeur. La surveillance passive des variations de vitesses sismiques par intercorrélation du bruit sismique ambiant montre ainsi un fort potentiel pour l’étude des zones critiques profondes et complexes à l’échelle du terrain et peut combler la lacune instrumentale qui existe actuellement en hydrologie.Des campagnes répétées de mesures avec un gravimètre portable à ressort ont également mis en évidence le fonctionnement différent de deux épikarsts et leur variabilité à l’échelle de la centaine de mètres. Des mesures mensuelles autour de l’observatoire ont mis en évidence l’homogénéité spatiale de cet épikarst dolomitique : toutes les stations ont les mêmes variations temporelles de stock d’eau. Au contraire, des mesures saisonnières en surface et en profondeur le long de la galerie souterraine calcaire de l’abîme de Saint-Ferréol ont montré une variabilité spatiale forte du stockage ainsi que du transfert rapide. La lithologie de l’épikarst est donc suspectée de jouer un rôle dans sa capacité de stockage. Lors de ces campagnes, la faiblesse du signal recherché a nécessité une méthodologie précautionneuse et un effet de température sur les mesures des gravimètres relatifs à ressort a été observé sur le terrain et quantifié en laboratoire.
https://tel.archives-ouvertes.fr/tel-01649606

NNT : 2016MONTT128
tel-01649606
https://tel.archives-ouvertes.fr/tel-01649606
https://tel.archives-ouvertes.fr/tel-01649606/document
https://tel.archives-ouvertes.fr/tel-01649606/file/2016_FORES_archivage.pdf

Éditeur(s) : Université des Antilles Études caribéennes
Résumé : Le tourisme de masse ayant déjà démontré ses limites et fait l’objet de critiques et d’indignation de la part des associations internationales de la protection de l’environnement cède peu à peu sa place au tourisme durable. Ce dernier tient compte de la protection de l’environnement et de la sauvegarde des richesses naturelles en offrant aux touristes des produits purement bio et des cultures tout à fait originales.Dans un contexte connu par sa complexité, vu les inégalités environnementales et sociales que connaît le Maroc, et pour remédier ce déséquilibre des acteurs économiques, des locaux dans la majorité des cas, ont opté pour des investissements touristiques dans les milieux ruraux. Ainsi des établissements touristiques ruraux commencent à prendre de l’ampleur, visant à consolider la notion du tourisme durable avec ses produits artisanaux locaux, ses variétés culinaires régionales et ses folklores saisonniers aux traditions bien enracinées. Mais ces actions sont-elles en mesure d’assurer un avenir prometteur à ces établissements ruraux, sans l’intervention de l’État qui a un rôle primordial à jouer en la matière de la formation et la qualification des ressources humaines dans le secteur du tourisme ; une formation pour préserver l’environnement et les ressources naturelles et donner un nouvel élan au tourisme rural dont la modernité demeure une référence essentielle.Par la beauté naturelle de leurs sites, la qualité de leurs aliments, le comportement clair et limpide de leurs personnes, les établissements d’hébergements touristiques ruraux marocains attirent déjà un nombre significatif de touristes qui viennent à l’origine pour un séjour de deux ou trois jours et prolongent souvent à une semaine séduits par la qualité du séjour. Eau pure, qualité de l’air, richesse culturelle, autant d’atouts qui justifient le soutien de ce genre de tourisme qui inspire notre enquête au niveau de la commune rurale d’Asni.
It is high people admitted that mass tourism has its limits as there have been consequences. Indeed several NGOS as well as international organizations aiming at the protection of the environment see that this destructive or harmful tourism is losing ground it is being substituted or replaced by eco-friendly tourism. This latter target the preservation of mother earth as well as its natural resources by providing a new type of tourism labeled rural tourism whose first and paramount objective is providing tourists with organic products. This green or rural tourism tries at all cost to promote artistic commodities, authentic cultures and purely traditional folk.Rural tourism is actually expecting more prosperity and progress but on condition that the local authorities and the government cooperate more to give a push to this kind of business via a perfect or division of human resources. Rural tourism represent a new image of modern tourism that aims to protect the environment and diversity. From the beauty of the natural land scape, the quality of the food served, the professionalism of the staff members the touristic accommodation units based in Moroccan countryside manage to attract a significant number of tourists, who often come for 2 or 3 days prolong their stay for a week for having fond a deep pleasure. The water is pure, the atmospheric air is filtered, the cultural wealth is vast, it is therefore appropriate to sustain and support this kind of tourism that inspires our investigation at the rural town of Asni.
Maroc
Asni

Droits : info:eu-repo/semantics/openAccess
urn:doi:10.4000/etudescaribeennes.7638
http://journals.openedition.org/etudescaribeennes/7638

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
Mass balances are often used to calculate sediment fluxes in foreland basins and denudation rates in adjacent mountain ranges on intermediate to long timescales (from a few tens of thousand to a million years). Here, we study the simple Quaternary catchment-alluvial fan system of the Kuitun River, in northern Tian Shan, to discuss some ideas about sediment storage, release, and bypass in relatively short (100 km long) sediment routing systems. This study shows that the Kuitun catchment and piedmont areas clearly present evidence of a significant and temporary storage of sediments during the Pleistocene. These sediments were then excavated and delivered farther into the foreland basin during the Holocene. The difference between the volumes of materials released from the catchment and piedmont areas (5.5 ± 1.7 km3) and the volume stored in a contemporaneous fan downstream (2.6 ± 0.6 km3) indicates that the latter did not trap the whole sediment load transported by the river. The alluvial fan was bypassed by 27 to 78% of this load toward its distal alluvial plain. If this value is well estimated, it implies a major volumetric partitioning of the deposits between the fan and the alluvial plain, with a very high sedimentation rate in the fan (1.97 ± 0.52 mm*y− 1) and a much lower one downstream (0.11 ± 0.11 mm*y− 1). However, this volumetric partitioning might only occur during periods with a very specific hydrological regime such as the Holocene deglaciation. Eventually, the peculiar sediment storage and release pattern within the Kuitun catchment and piedmont areas during the Pleistocene and Holocene complicates the calculation of mean paleodenudation rates using either sediment budgets or in situ produced cosmogenic nuclides.
ISSN: 0169-555X

insu-00985283
https://hal-insu.archives-ouvertes.fr/insu-00985283
https://hal-insu.archives-ouvertes.fr/insu-00985283/document
https://hal-insu.archives-ouvertes.fr/insu-00985283/file/jolivet-et_al-2014_HAL.pdf
DOI : 10.1016/j.geomorph.2014.01.024

Éditeur(s) : HAL CCSD Springer Verlag (Germany)
Résumé : International audience
Surface displacements due to temporal changes in environmental mass redistributions are observable in the coordinate time series of many Global Navigation Satellite System (GNSS) sites. In this study, we investigated the effect of loading on estimates of tectonic velocity computed from campaign-style GNSS observations. The study region is in the Pyrenees mountain range between France and Spain (ResPyr campaigns). In this area, seismic activity is continuous and moderate and the expected amplitude of the horizontal tectonic velocity is less than 0.5 mm/yr. In order to determine the velocity, 4 sparse GNSS campaigns were carried out from 1995 to 2010. Considering this small rate of deformation, loading phenomena can contribute a non-negligible artifact to the velocity computation that could affect our geodynamical interpretation. In this investigation, we specifically considered the atmospheric, hydrological, and non-tidal ocean loading phenomena. The computed loading deformations for this region show the horizontal displacements are dominated by the non-tidal ocean loading (maximum 4 mm for the North and 3.1 mm for the East components); the main vertical contributions are due to the atmospheric and continental water storage loading (maximum 14.3 for the atmosphere and 8.1 mm for the hydrology, respectively). We have found that the dominant loading effect on the horizontal velocity is the non-tidal ocean loading (mean of 0.11 mm/yr), whereas the vertical component is dominated by the hydrological loading (mean of 0.21 mm/yr). Since the study area is in a mountainous region, we also analyzed the difference between the atmospheric and the topography dependent atmospheric loading models at our GNSS campaign sites. We did not find any significant difference between the two atmospheric loading models in terms of horizontal velocity. Finally, we performed simulations to identify the optimum timing and frequency of future GNSS campaigns in this area that would minimize the loading effects on tectonic velocity estimates.
ISSN: 0039-3169

hal-00963629
https://hal.archives-ouvertes.fr/hal-00963629
DOI : 10.1007/s11200-012-0458-2

Éditeur(s) : Université des Antilles Études caribéennes
Résumé : Cette étude souligne l’importance des enjeux touristiques pour les îles tropicales. La singularité des espaces est trop souvent négligée en raison de la vigueur des représentations fantasmées de l’île tropicale qui est perçue tel un lieu paradisiaque, un lieu d’accomplissement de désirs illimités où s’écoule une vie facile, avec ses rivages ensoleillés, entre récifs coralliens et plages de sable blanc bordées de cocotiers. Ces richesses immatérielles reposent sur des ressources bien réelles, abondantes et vulnérables, à l’image des emblématiques récifs coralliens. Certes les destinations insulaires tropicales ne connaissent pas les niveaux de fréquentation des grandes régions du monde, mais leurs flux doivent être reconsidérés au regard des caractéristiques de ces territoires (faible superficie, charge de population, rareté de la terre, limites des ressources) qui nécessitent la définition d’indications spécifiques. Mais l’avènement d’un tourisme de masse dans ces ultimes frontières, ces « Pleasure Periphery » nécessite de s’interroger sur la viabilité des stratégies de développement mises en œuvre autour du tourisme.
This study highlights the importance of tourism issues for the tropical islands. The singularity of the spaces is too often overlooked because of the strength of fantasized representations of the tropical island which is seen as a paradise, a place of accomplishment desires unlimited with an easy life, with its sunny shores, between coral reefs and white sandy beaches lined with coconut trees. These intangible wealth are based on real resources, abundant and vulnerable, like the emblematic image of coral reefs. Although the tropical island destinations are not supported the weight of the major touristic regions of the world but their flows should be reconsidered in the light of the characteristics of these territories (small size, load population, shortage of land, limits of resources) that require defining specific indicators. But the advent of mass tourism in these last frontiers, these "Pleasure Periphery" needs to question the sustainability of tourism development strategies.

Droits : info:eu-repo/semantics/openAccess
urn:doi:10.4000/etudescaribeennes.852
http://journals.openedition.org/etudescaribeennes/852

Éditeur(s) : HAL CCSD Nature Publishing Group
Résumé : International audience
Carbon is transported from Earth's surface into its interior at subduction zones. Carbonates in sediments overlying hydrothermally altered rocks (including serpentinites) within the subducted slab are the main carriers of this carbon1. Part of the carbon is recycled back to the surface by volcanism, but some is transferred to the deep Earth1, 2. Redox transformations during shallow subduction control the transfer and long-term fate of carbon, but are poorly explored1, 3. Here we use carbon stable isotopes and Raman spectroscopy to analyse the reduction of carbonate in an exhumed serpentinite-sediment contact in Alpine Corsica, France. We find that highly crystalline graphite was formed during subduction metamorphism and was concentrated in the sediment, within a reaction zone in direct contact with the serpentinite. The graphite in this reaction zone has a carbon isotopic signature (δ13C) of up to 0.8±0.1‰, similar to that of the original calcite that composed the sediments, and is texturally associated with the calcium-bearing mineral wollastonite that is also formed in the process. We use mass-balance calculations to show that about 9% of the total carbonaceous matter in the sedimentary unit results from complete calcite reduction in the reaction zone. We conclude that graphite formation, under reducing and low-temperature conditions, provides a mechanism to retain carbon in a subducting slab, aiding transport of carbon into the deeper Earth.
ISSN: 1752-0894

hal-00903464
https://hal.archives-ouvertes.fr/hal-00903464
DOI : 10.1038/NGEO1827

Éditeur(s) : HAL CCSD Oxford University Press (OUP)
Résumé : Geodynamic models incorporating metamorphic phase transformations almost invariably assume the validity of the Boussinesq approximation that violates conservation of mass. In such models metamorphic density changes take place without volumetric effects. We assess the impact of the Boussinesq approximation by comparing models of orogeny accompanied by lower crustal eclogitization both with and without the approximation. Our results demonstrate that the approximation may cause errors approaching 100 per cent in characteristic measures of orogenic shape. Mass conservation errors in Boussinesq models amplify with model time. Mass conservative models of metamorphism are therefore essential to understand long-term tectonic evolution and to assess the importance of the different geodynamic processes.
ISSN: 0956-540X

hal-00617480
https://hal.archives-ouvertes.fr/hal-00617480
DOI : 10.1111/j.1365-246X.2011.05052.x

Éditeur(s) : HAL CCSD Cambridge University Press (CUP)
Résumé : The natural 15N abundance method for estimating symbiotic biological N2-fixation was tested on legume trees from two rain forests on contrasting soils (oxisols and spodosols) in French Guiana. When possible, the significance of N2-fixing species in the plant community was evaluated in terms of density, biomass and contribution of N2-fixation to the building up of the total nitrogen mass in the leaves. Of the two sites, the rain forest on spodosols was the less favourable for application of the [delta]15N method: the available soil nitrogen was isotopically similar to fixed-N2. Hence, the results showed that a reliable estimate of N2-fixation could not be obtained. A substantial contribution of fixed-N2 to the nitrogen nutrition of legumes was found on oxisols, with an average value of 54 % Ndfa (Nitrogen derived from the atmosphere). The contribution of the N2-fixing legumes to the biomass of the stand was estimated to be 2 t ha[minus sign]1 for the leaf biomass and 136 t ha[minus sign]1 for the total above-ground plant biomass. With 7.5 % of trees in the stand able to fix N2 (462 out of 6156), N2-fixation was estimated to be 7 kg ha[minus sign]1 y[minus sign]1. These results are the first use of the [delta]15N method to estimate nitrogen input by N2-fixing legumes to a natural rain forest. The inter-site variability observed in the [delta]15N of the non-fixing plants suggested different nitrogen-cycling processes in the two soils. The [delta]15N of the non-N2-fixing plants could be related to the soil nitrogen availability and be used as an indicator of efficient or non-efficient nitrogen-cycling rain forests. The spatial variability of the [delta]15N in the plant-available soil nitrogen pool and the nitrogen balance in tropical rain forests are discussed.
ISSN: 0266-4674

hal-01032201
https://hal.archives-ouvertes.fr/hal-01032201
DOI : 10.1017/S0266467499000644