Dissertationen zum Thema „Gyre de l'Océan Indien“
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Thibault, Margot. „Composition, abundance, origin and distribution of plastic pollution accumulated in the Southern Indian Ocean gyre“. Electronic Thesis or Diss., La Réunion, 2024. https://elgebar.univ-reunion.fr/login?url=http://thesesenligne.univ.run/24_01_M_THIBAULT.pdf.
Der volle Inhalt der QuelleThe majority of mismanaged plastic waste enters the marine environment. Once in the oceans, these plastics drift until reaching subtropical convergence zones, where they accumulate to form “Garbage Patches”. Five zones have been discovered, including one in the southern Indian Ocean. This latter patch has undergone limited surface observation studies, and several predicted models indicate a different location, placing it either west or east of the basin. Supposedly the second most polluted “Garbage Patch” after the North Pacific, it is crucial to identify it for effective intervention accurately. Within this context, the doctoral project aimed to determine the composition, concentration, and origin of plastic debris accumulated in the Southwest Indian Ocean. Since the project's inception, 19 oceanographic campaigns have been conducted to visually monitor macro-debris (> 2.5 cm) and collect microplastics by manta trawl deployment (500 μm – 5 mm). Surveys of marine debris (macro-meso (5 mm – 2.5 cm) beached on uninhabited, remote islands have also been carried out to assess the concentration that does not remain on the surface. Furthermore, a long-term study of plastic pollution was initiated by identifying bio-indicator species in the region. All observations have been compared or complemented with plastic dispersion predictive models in the Indian Ocean. Of all the marine debris collected or observed, 95% consisted of plastics. Among plastics, the predominant subcategory was pre-existing fragmented hard plastics found on the ocean surface, beached on uninhabited islands, and ingested by bio-indicator species. The primary composition of these polymers was polyethylene and polypropylene, and it did not differ between the ocean surface and beaches. A concentration gradient of microplastics was also identified, ranging from 10^3 items.km^-2 at 40°E to 10^5 items.km^-2 at 65°E on latitudes 30/33°S. This gradient has been confirmed by plastic dispersion predicted models, although they tend to underestimate it. In addition, some of the macroplastics stranded on the islands originated mainly from Southeast Asian food packaging. Three species have been identified for long-term monitoring of plastic pollution in the region: loggerhead turtles (Caretta caretta), Barau's petrels (Pterodroma baraui), and tropical shearwaters (Puffinus baillonni). Future studies should include increasing sampling in the central and eastern parts of the Indian Ocean basin during different seasons, studying the impact of plastic debris on associated ecosystems, and developing tailored management solutions
Cornuault, Josselin. „Biodiversité, biogéographie et évolution des hémosporidies dans l'océan Indien“. Toulouse 3, 2012. http://thesesups.ups-tlse.fr/1845/.
Der volle Inhalt der QuelleUnderstanding biodiversity patterns is one of the major goals of ecology. Despite our increasing knowledge in the fields of evolutionary biology and ecology, the complexity and the multiplicicty of the processes underlying the assemblage of ecological systems continue to puzzle scientists. The field of biogeography has developed in an attempt to explain present species distributions by unravelling the factors involved in community assembly. The work presented in this manuscript aims at describing and understanding which processes were involved in the building of insular parasite communities. It specifically focuses on hemosporidian blood parasites infecting birds of the Indian Ocean and provides new insights into the processes explaining parasite diversity in insular systems. Results suggest that the hemosporidian communities of the Mascarene archipelago were assembled through a combination of multiple colonisations and in-situ diversifications. In particular, a group of Leucocytozoon parasites found their way to a number of islands in the Indian Ocean by following their Zosterops hosts in their evolutionary radiation. Such congruence of biogeographical histories of hosts and parasites has never been described in hemosporidians and allowed the identification of several co-divergence events, offering the possibility to date the parasite radiation and to propose a rate of molecular evolution for the parasites. Leucocytozoon parasites are also reported to be more diverse than Plasmodium in the Mascarene archipelago. This pattern may be the result of earlier and more numerous colonisations by Leucocytozoon. Alternatively, a lower turnover rate in Leucocytozoon could induce the same pattern. Finally, two lineages of Leucocytozoon are geographically segregated within the island of Réunion and we show that this pattern cannot be due to the sole effect of environmental factors and we suggest that competition or differential vector preference be involved
Lyard, Florent. „Modélisation de la marée océanique : application à l'océan indien“. Grenoble 1, 1992. http://www.theses.fr/1992GRE10157.
Der volle Inhalt der QuelleDongmo, Wamba Mathurin. „Tomographie de l'Océan Indien par inversion de forme d'onde“. Thesis, Université de Paris (2019-....), 2020. http://www.theses.fr/2020UNIP7077.
Der volle Inhalt der QuelleThe arrival of some plumes and the birth of hotspots at the Earth surface is more likely the cause of the break up of the Pangea ~200 Ma ago, during the jurassic era. The Gondwana was formed by many continental masses like Africa, Australia, India and Antarctic. The late cretaceous was affected by a biological crisis caused by a volcanic and/or asteroid cataclysm which provoke the disappearance of 90% of life on the Earth including dinosaurs, and produced India Deccan trapps with an area of 2 millions km^2 and thickness of 2.5-3 km. This volcanic disaster was associated with the birth of la Réunion hotspot ~65 Ma years ago, from there the india plate entered into the northward migration with a velocity of about 18-20 cm/year, and the closure of the Tethys ocean in front of the indian plate started; in the meantime the raising of basaltic lava from the indian ridges formed a new ocean floor behind the indian plate: this was the birth of indian ocean. In 1953 the Canadian researcher Tuzo Wilson suggested that such an intra-plate volcano may be due to a fixed hotspot in the mantle capable to create successive volcano on the surface; later in 1971 Jason Morgan suggested that the hotspot is fed by a mantle plume rising from the core-mantle boundary due to thermal instabilies. The goal of this thesis is to investigate the actual state of the plume in the entire indian ocean, responsible of many volcanic islands such as Maldives, Maurice and Réunion. By applying waveform inversion we are able to image the earth structure down to the lower mantle; we use Rhum-Rum data and also data collected from FDSN (Federation of Digital Seismograph Networks) data center to perfom our inversion. We perform the forward modelling with the spectral element method. For this regional case we use RegSEM (regional spectral element method) to compute synthetic seismograms that were compared to real seismograms later on. We divided the waveform into several wavepackets, each wavepacket corresponds to a specific mode. We inverted for two parameters, isotropic velocity and radial anisotropy.The result shows a large velocity anomaly channel extending from East to West over nearly ~2100 km in the Mascarene basin at a depth of 200 km. Our model also bring to light a plume under the Reunion hotspot with a broad head in the upper mantle and a narrow tail anchored in the lower mantle. Our model sheds light on the connection between the Reunion plume and the South African LLSVP (Large Low Shear Velocity Province), as well as between the Mascarene anomaly and the base of the lower mantle
Rocca, Olivier. „La tradition naturelle dans les politiques de l'Océan indien“. Aix-Marseille 3, 1999. http://www.theses.fr/1999AIX32026.
Der volle Inhalt der QuelleThe natural tradition gives the framework and the structure to understand many links between the political reason and its practice in natural environment. The natural tradition, which considers that desire is the central force which organizes social life and the political think it self, helps to understand many crisis of the indian ocean region, and prepares a new reflection about modernity
Le, Mouël-Conte Virginie. „La problématique du développement durable insulaire à travers l'exemple des îles du sud-ouest de l'Océan Indien“. Nice, 2003. http://www.theses.fr/2003NICE0032.
Der volle Inhalt der QuelleJacob, Jensen. „Contribution à la tectonique des plaques de l'océan Indien oriental“. Paris, Institut de physique du globe, 2013. http://www.theses.fr/2013GLOB0002.
Der volle Inhalt der QuelleThe frequent earthquakes in Indonesia are associated with the active subduction of the northern Wharton basin under Sunda trench. To better understand the subduction mechanism the age and structure of the subducting lithosphere have been analyzed by conducting a detailed marine magnetic interpretation of the Wharton basin. Validation of the identified magnetic isochrons is achieved by two-plate kinematic reconstructions for chron 20 young to 26 old, and by three-plate reconstructions involving Australia, Antarctica and India for the older chrons 34 young to 27 young, for which no conjugate anomalies exist in the basin. The resulting age and structure obtained for the missing part of the basin are draped on the top of the subducted lithosphere determined by seismic tomography to investigate the subduction processes and their consequences. The age and spreading rate influence physical parameters like the thickness, buoyancy, and rheology of the subducting lithosphere, which in turn result in variable "subductability" of the lithosphere, varying depth of the trench and its deviation from a regular arc. The subducted long-offset fracture zones and spreading axis play an important geodynamic role in opening asthenospheric windows through the deep slab, whereas subducting features like plateaus and seamounts affects shallower processes at the trench and in the seismogenic zone. To extend the results obtained by our three-plate reconstructions on the controversial Late Cretaceous spreading history of Australia and Antarctica, we investigate the early opening and spreading history of this plate boundary using the Bullard Contour Fit method. The method is appropriate for sinuous isochrons and in absence of clear fracture zones. Two pairs of symmetrical features are observed in the satellite-derived free-air gravity anomaly map over the conjugate margins, the strongest one interpreted as the continent-ocean boundary. They are considered as isochrons and tentatively dated 128 and 94 Ma. A proper reconstruction at 128 Ma is attained in three separate sections, with the western section corresponding to the motion between Australia-East Antarctica, the central one to the motion between the Polda Block (a transient micro-continent) and East Antarctica, and the eastern one to Tasmania and West Antarctica. The eastern margins of Australia and Tasmania are aligned. The conjugate margins of reconstructed Australia, Tasmania and West Antarctica on one hand, Lord Howe Rise and the Campbell Plateau (Zelandia) on the other hand, fit a small circle and suggest a transform motion. Aligning the Bellona Trough with the Bass Strait as an extension of the Southern Australia Fracture Zone predicts a total 600 km of transform motion, before the Tasman Sea and Pacific- Antarctic Ridge opened at ~83 Ma. The southeastward translation of East Antarctica resulted in compression and crustal thickening in West Antarctica, creating the Trans-Antarctic Mountains at the edges of different provinces - craton and orogenic terranes - and rheology. The initial opening of Australia-Antarctica is likely related to the Kerguelen hotspot inception at ~120 Ma
Carletti, Isabelle. „Étude de molécules bioactives isolées d'éponges marines de l'Océan Indien“. Nice, 2000. http://www.theses.fr/2000NICE5469.
Der volle Inhalt der QuelleSonzogni, Corinne. „Calibration et application de la méthode paléothermométrique des alkénones aux sédiments quaternaires de l'océan indien“. Aix-Marseille 3, 1997. http://www.theses.fr/1997AIX30033.
Der volle Inhalt der QuelleFagel, Nathalie. „Flux argileux du Néogène au Quaternaire dans l'Océan Indien nord : mise en évidence et interprétation“. Lille, 1993. http://www.theses.fr/1993LIL10193.
Der volle Inhalt der QuelleChakroun, Abdellatif. „Problèmes stratégiques, conflits armés et consentement à l'intervention dans la région de l'Océan indien“. Paris 10, 1994. http://www.theses.fr/1994PA100038.
Der volle Inhalt der QuelleChevallier, Luc. „Tectonophysique des volcans : exemples pris dans l'Océan indien et l'Atlantique Sud“. Phd thesis, Grenoble 1, 1987. http://tel.archives-ouvertes.fr/tel-00744418.
Der volle Inhalt der QuelleDuchiron, Bertrand. „Variabilité interannuelle de la pluviométrie dans l'espace riverain de l'océan indien“. Paris 7, 2002. http://www.theses.fr/2002PA070022.
Der volle Inhalt der QuelleThe interannual variability of rainfall in the coastal areas of the Indian ocean was analysed for the period 1946-1975 and regionalized then we establish statistical forcasting models of rainfall from oceano-atmospheric circulation indicators. A set of 130 well-spatially-distributed stations were selected from a pluviometric database. Missing values were statistically replaced and the output dataset was validated. Multivariate analyes (PCA and clustering analysis) were applied on these data to extract 21 homogeneous pluviometric regions. Times series are strongly correlated over a lag period ranging from 1 to 3 months with some atmospheric and oceanic anomaly indices recorded over the Indian and Pacific oceans. .
Somers, Shehnaz. „Le décepter dans la littérature orale de l'océan Indien : étude comparée“. Master's thesis, University of Cape Town, 1993. http://hdl.handle.net/11427/21490.
Der volle Inhalt der QuelleThis thesis examines the figure of the Trickster In the traditional literature of the Indian Ocean islands of the Seychelles, Mauritius and Reunion. Originating from a unique blend of cultures, the popular literature of these islands lend itself to a comparative study with other folklore. The first chapter considers various Interpretations of the Trickster and examines this figure in other traditional cultures. In this regard, we consulted the major works done on the Trickster in order to draw, in the second chapter, comparisons between the Trickster figures In these cultures and in that of the Indian Ocean Islands. The third chapter sets out the various structures of the African Trickster-tales as presented by certain theorists. These same structures appear, either wholly or in slightly altered ways, in the Trickster-tales of the Indian Ocean. The fourth chapter, therefore, is a structural analysis of the Indian Ocean tales, which accounts for the similarities and differences that exist between these tales and the African ones. The African and Indian Ocean folktales share a common function: they serve to Instruct and to Impart knoYJiedge. Thus the fifth chapter examines the lessons conveyed by the Indian ocean Trickster-tales and discovers that they can be of a practical, moral or linguistic nature. Certain themes and motifs which appear in the Indian Ocean tales are also recurrent in European and African folktales. The final chapter deals Ylith these themes and shows how they have been appropriated and assimilated into the social and cultural framework of the Indian Ocean islands. Having found that the Trickster appears in all cultures, we conclude this study by establishing reasons for the popularity and universality of the Trickster figure.
Davy, Céline. „Analyse du bruit microsismique associé à la houle dans l'océan Indien“. Thesis, La Réunion, 2015. http://www.theses.fr/2015LARE0024/document.
Der volle Inhalt der QuelleSeismic data recorded on oceanic islands can be used to analyze the swell through its signature in the microseismic noise. We first analysed the "secondary" noise sources, which are generated by the interaction of ocean waves with similar period within a storm, a cyclone or by the reflection phenomena off the coast. By analyzing secondary microseisms at the scale of the oceanic basin, we first performed a spatio-temporal tracking of the source, even localized thousands km off the recording seismic stations. Secondly, in the long-term, they can be used to follow the global climate change related to the ocean waves activity in a specific region. We also studied the "primary" seismic noise sources, which are created by the direct interaction of ocean waves with the coast. By analyzing these primary microseisms, we succeeded to characterize ocean waves locally in terms of amplitude, period, and, sometimes, direction of propagation. This showed that it is possible to use a seismic station as an ocean waves gauge to get precious swell data, particularly in remote and poorly instrumented areas. In the context of the Iles Éparses and of La Réunion Island, we studied a few extreme swells, which occur there frequently and can have strong social and environmental consequences. Finally, by using a temporary network of seismic stations installed in La Reunion, we studied the spatial variations of the seismic noise level across the island to characterize the swell impact on the different coasts. This study enables us to identify the most exposed spots to the swell, which may be attractive for generating renewable energy with this powerful resource yet underexploited
Izard, Lloyd. „Structuration spatiale et variabilité des écosystèmes mésopélagiques dans l'Océan Indien Sud“. Electronic Thesis or Diss., Sorbonne université, 2023. http://www.theses.fr/2023SORUS621.
Der volle Inhalt der QuelleThe Southern Indian Ocean hosts diverse oceanic environments, pelagic communities, and predator populations that have recently led to the establishment of conservation areas and UNESCO World Heritage recognition. However, predator populations in this region have displayed signs of decline, likely attributed to the impacts of climate change and prey dynamics. These prey populations consist predominantly of zooplankton and micronekton, playing a crucial role in marine ecosystems by influencing biogeochemical cycles and the transfer of energy and biomass along the trophic web. Nevertheless, the study of their structuring is intricate due to their deep distribution in the mesopelagic zone (200-1000 m) and their daily vertical migrations, making it one of the least explored areas on a global scale. In this thesis, we employ active acoustics, which provides high spatial and vertical resolution for tracking these organisms, to investigate the structuring of mesopelagic ecosystems in two contrasting oceanic systems. We initially examined their responses in a transition zone between these oceans, within the Saint-Paul and Amsterdam Islands region. Our findings indicate that nycthemeral migrations are the primary factor vertically structuring pelagic organisms, even within a pronounced transition zone. Three spatially coherent regions were identified, sharing common environmental and acoustic features. Observations at 38 kHz (commonly used in hydroacoustics) confirmed increased biological activity in the subtropical zone and a minimum in the subantarctic zone. However, our analyses also reveal a distinct acoustic response based on the acoustic frequency considered, in terms of vertical structuring and integrated biomass. Additionally, the low levels measured in the Southern Ocean appear inconsistent with the high biomasses consumed by the large marine predator populations in this region. These observations highlight an acoustic resonance issue in the study of these organisms. To investigate this phenomenon, our second study focused on the structuring of communities at a regional scale, proposing a two-frequency acoustic landscape classification, both probing depths of up to 1000 m. Four spatially coherent regions were identified based on the combination of vertical structuring at the two considered frequencies. The results of this study reveal a shift in the dominance of acoustic responses between 38 and 18 kHz at the subantarctic front, supporting the hypothesis of a community change at these latitudes and raising questions regarding the use of 38 kHz as a descriptor for mesopelagic communities. Given the complexity of acoustic data (potentially multivariate, with distinct vertical ranges, and four-dimensional), the work presented in this thesis also contributed to the development of functional analysis methods to reconcile the horizontal, vertical, and temporal variability of these ecosystems. As marine ecosystem management requires an understanding of the dynamics of these systems and the structuring of the communities within them, our work has also had implications in marine conservation. At the national level, it contributed to the extension of the Saint-Paul and Amsterdam Islands Nature Reserve, and at the international level, it contributed to the ecoregionalization of the pelagic zone in the subtropical and subantarctic region of the South Indian Ocean
Rivière, Françoise. „Effet des dépenses publiques d'infrastructures et d'éducation sur la croissance : approches macro-économique et micro-économique : cas de l'île de la Réunion, de l'île Maurice et de Madagascar“. Paris 1, 1998. http://www.theses.fr/1998PA010007.
Der volle Inhalt der QuelleThe aim of the thesis is to study the effect of public expenditures on infrastructures and education on economic growth of Reunion, Mauritius and Madagascar. The first part draw a synthesis of recent litterature dealing with endogenous growth and empirical investigations evaluating the productive impact of infrastructures and human capital. The second part consists of a macroeconometric analysis of the effect of public capital and human capital stocks on economic growth. This analysis lays on a description of the recent economic evolutions of the three economies, the construction of a database for each island over 1965-1994 and the use of various econometric methods (chronological series, econometrics of panel, simultaneous equations system). The econometric results clearly show a positive impact of human and public capital on Reunion and Mauritius growth. In contrast, the productive contribution of education is not significative as far as Madagascar is concerned. The third part is based on the analysis of microeconomic data from a survey concerning a sample of industrial firms in the three islands. An econometric study evaluate the impact of different level of education and different development obstacles on the firms productivity. The results are similar to those provided by the macroeconomic approach and reflect the different level of development of the three educative systems. The conclusions of the microeconomic analysis tend to precise the role of human capital and infrastructure dodation on economic development : others factors tend to hamper the development of exports (credit restraints, lack of external markets for Reunion; lack of qualified people for Mauritius; instable political and economical climate for Madagascar)
Imbert, Thierry. „La sédimentation volcanogène récente dans le Nord-Est de l'océan indien : téphrochronologie et diagenèse précoce“. Paris 11, 1988. http://www.theses.fr/1988PA112237.
Der volle Inhalt der QuelleMarine tephras studies are of great benefit for understanding the explosive volcanic history of an insuar arc, and also to evaluate their contribution to oceanisedimentation through their alteration products. In the first part this work propose a chronology of tephra deposition in the North Eastern Indian Ocean (Bengal Bay. Ninety east Ridge, Wharton Basin) and presents five periods of explosive volcanic pulse within the arc: 1; 0. 7; 0. 4; 0. 25; 0. 07 My. The glasses of rhyolitic composition, and widely dispersed by wind relate with ignimbrite formation on land. Ash layer deposits in the Bengal Bay originate from Toba eruptions since 0. 26 My, and from the North of Sumatra prior to this date. The deposits on the Ninetyeast Ridge come from the Padang Aerea (Central Sumatra. 0. 65 and 0. 07 My). The Sunda Strait volcanic activity is Jess dispersed than the ethers and deposits are limited to the North of the Warthon Basin. The second part discusses the first stage of alteration of aciditic lasses. The hydration ts heterogenous within individual ash layers and is related to the environment (bathymetry, burial, magma initial composition,. . . ). Ultrathin section studies revealed the neoformation of halloysite and illite on glass deposit insiliceous sediments, since the Eocene time. Experiments carried out at 25°c under closed conditions for one yearconfirm the exitence of a Si Al stage, and K incorporation during the beginning of the alteration process
Marsac, Francis. „Etude des relations entre l'hydroclimat et la pêche thonière hauturière tropicale dans l'océan Indien occidental“. Brest, 1992. http://www.theses.fr/1992BRES2027.
Der volle Inhalt der QuelleRahalison, Chantal. „Les îles du sud ouest de l'océan indien et la coopération régionale“. Toulouse 1, 1989. https://elgebar.univ-reunion.fr/login?url=http://thesesenligne.univ.run/H/1989TOU10012_Rahalison.pdf.
Der volle Inhalt der QuelleFour independents states and one french department located in the south west of the Indian ocean, all considered as underdeveloped for their respective social and economic situation are today firmly involved in regional cooperation as for many underdeveloped countries. They are Madagascar, Mauritius, the Seychelles, the Comoros and la Reunion that history and geography have already put together. The regional cooperation which constitute a solution to their development problems concerns all various scope from tourism exchanges through problems of fishing to cultural and social aspect. The relations among the islands have always existed and are still meeting many difficulties. Nevertheless an important progress has been made since the creation of the COI (commission of the Indian ocean )
Ahamada, Mmadi. „La Commission de l'océan indien, une organisation de développement et de coopération“. Paris 5, 2011. http://www.theses.fr/2011PA05D012.
Der volle Inhalt der QuelleSince its creation in 1984, the environment of the Indian Ocean Commission (IOC) knew profound turnovers. The internal and international evolutions appreciably transformed the stakes in the sub-regional cooperation. The members of the IOC suffer in common from the environmental fragility, the Small Island and vulnerable savings in front of natural disasters. The IOC is thus confronted with the challenge to find answers to questions and complex phenomena; in particular, the development of its island spaces. The complexity of these last ones requires another thought of development and the IOC is called to reorganize its axes of cooperation and modify its strategies to reach economic, social and sustainable development of it members. In spite of the progress achieved thanks to the cooperation of the IOC, its members collided with profound systematic disparities in the field of business, finance, foreign debt, rights and technology transfers, which limited their capacity to cooperate in a significant way. A whole series of structural factors also hindered the cooperation between members of the IOC. The incapability of the systems of communication and the lack of connectivity between countries as well as on national scale, constituted a major problem. Given the past and present sub-regional and regional experiences, can we talk in terms of the success of this approach for economies such as those of the islands of the southwest of the Indian Ocean? Can the sub-regional cooperation as it was and continues to be directed, allow its members to reach to the fixed objectives? How and in which measure can the IOC play a supranational role? Has IOC really an authority to oblige its members to respect their commitments? In short, we can wonder as to what extent the IOC can make the cooperation between it members a real control lever of development
Kane, Seydou Oumar. „Les relations maritimes et commerciales de Nantes avec l'océan Indien de 1825 à 1884“. Nantes, 1992. http://www.theses.fr/1992NANT3014.
Der volle Inhalt der QuelleDuring the period 1825 to 1884, nantes had organized 2183 maritimes expeditions for the indian ocean. This trading navigation had been domined by the traffic with the reunion and maurice. Theses two islands had noted the arrival of 1902 ships from the loire harbour in exchange the indians and mayotte, nossi-be, madagascar had received respectively 215 and 66ships. The importations had been composed essentialy of crude sugar. This farm produce was used for resupply nantes's refineries. The others importations consist of coffee, rice, spices and seasonings, oleaginous matters and animal's produces as horns and skin of oxen or buffalo. Nantes had exported bound for the indian ocean colonies several animals, foodstuffs and material of construction. In 1883-1884, the crisis of four refineries brought about the decline of this trade between nantes and indian ocean
Gourlan, Alexandra. „Stratigraphie isotopique du Néodyme dans l'océan Indien: Paléocirculation océanique et Érosion continentale“. Phd thesis, Institut de physique du globe de paris - IPGP, 2006. http://tel.archives-ouvertes.fr/tel-00494539.
Der volle Inhalt der QuelleLo, Monaco Claire. „Etude du carbone anthropique dans l'Océan Indien Austral : Distribution et variabilité décennale“. Phd thesis, Université Pierre et Marie Curie - Paris VI, 2006. http://tel.archives-ouvertes.fr/tel-00121242.
Der volle Inhalt der QuelleBouchard, Christian. „Le contexte énergétique des petites îles du sud-ouest de l'océan Indien“. Agence Régionale de l’Énergie Réunion (ARER), 2005. https://zone.biblio.laurentian.ca/dspace/handle/10219/329.
Der volle Inhalt der QuelleGourlan, Alexandra. „Stratigraphie isotopique de néodyme dans l'Océan Indien : Paléocirulation océanique et Erosion continentale“. Paris 7, 2006. http://www.theses.fr/2006PA077132.
Der volle Inhalt der QuelleNeodymium isotopic composition in marine sediment is a powerful proxy to investigate the past ocean circulation. Because Nd residence time is short (200-1000 yr), Nd is not isotopically homogenized in the global ocean. So, the Nd seawater isotopic composition is a function of changes in paleocirculation, source provenances and varies with the intensity of weathering of continents or volcanic arcs. We have applied a new technique using acetic acid for reconstructing the evolution of the deep seawater and the detritic signals in the Indian Ocean. The reliability of our technique has been assessed by comparison with techniques developed by Bayon et al. , (2002) and by Burton and Vance (2001). With this technique, we have studied two thematics: the equatorial Indian Ocean circulation and the Himalayan continental erosion. To reconstruct the evolution of the oceanic flow from the Pacific to the equatorial Indian Oceans since the Miocene, four ODP sites were chosen on both oceans. Remarkable results were obtained. The coincidence in εNd of seawater of two ODP sites distant from 3000 km establishes the existence of a strong broad westerly oceanic current (MIOJet) in the Indian Ocean from 13 to 3 Ma after a reorganization of the Indian Ocean paleocirculation and proves a rapid closure of the Indonesian seaway at 3-4 Ma in less than 2 Ma. We have also analyzed the seawater and the detritic Nd isotopic compositions of a site located near the Bengal fan on glacial-interglacial alternance. Results have shown that the εNd and δ18O curves fluctuate in conjunction during these periods and that εNd fluctuations were linked to the erosion regime in the Himalaya-Tibet and were not linked to the variations of the intensity of the deep ocean conveyor belt. These variations most probably reflect a significant storage of ice in the Himalaya-Tibet highlands during glacial periods
Djoumoi, Mohamed. „Plausibilité de la couverture boursière des prix des denrées de l'Océan Indien“. Montpellier 1, 2003. http://www.theses.fr/2003MON10048.
Der volle Inhalt der QuelleMaraldi, Claire. „Modélisation de la dynamique barotrope de l'océan Indien Austral : application à l'altimétrie“. Toulouse 3, 2008. http://www.theses.fr/2008TOU30168.
Der volle Inhalt der QuelleSeismic soundings, ice shelf elevation measurements and barotropic tide modelling, has been applied to estimate the bathymetry beneath the Amery Ice Shelf more accurately. The barotropic models have been validated by comparison with in situ and altimetric elevation measurements and current meter data. The comparison of our solutions with global models reveals the important role of regional modelling in coastal areas and beneath the floating ice shelves. The hydrodynamic model outputs have then been analysed. Further analysis of our regional tidal simulation has allowed us to examine and understand the tidal dynamics in the study region. We have then computed the energy budget to assess the model consistency and distinguish high dissipation sub-regions. In addition, using ECMWF atmospheric forced modelling, we could study barotropic circulation in the Southern Indian Ocean, characterize its modes of variability and quantify the impact of various forcing terms brought into play. Finally, the joint analysis of current velocities from the two simulations, baroclinic geostrophic and Ekman currents, has allowed us to estimate lateral mixing over the Kerguelen Plateau. Predominantly due to tidal velocities, this mixing explained the horizontal extension limits of the annual phytoplanktonic bloom observed over the northern plateau. Models of high frequency dynamics have also been applied to study altimetric signals. Firstly, they have been used as indicators to define regions of internal tide generation. By analysing altimetric measurements in these regions, we have characterized the sea surface signature of those waves, and estimated the energy dissipated through this process. The regional barotropic solutions have then served to correct altimetric measurements from aliased high frequency processes. The impact of these corrections has been quantified in coastal regions and beneath the Amery Ice Shelf. The corrected altimetric measurements have allowed us to study the local oceanic dynamics around the Kerguelen Islands. Over the Amery Ice Shelf, it has allowed us to observe a thinning of the floating shelf over its central part during the ENVISAT period
Martin, Noémie. „Les productions céramiques de l'océan indien occidental : implications culturelles au carrefour d'influences“. Paris, INALCO, 2010. http://www.theses.fr/2010INAL0023.
Der volle Inhalt der QuelleThe populations of the Eastern coast of Africa, Comoros ans Madagascar have participated in the trade networks of the Indian ocean since the 8th century. However, the narratives of the Arab Middle Age have show a break between the east-african communities and those of Comoros and Madagascar, understanding these in a geographic ans cultural continuum with the population of South-Eastern Asia. The anthropologic, ethnologic, linguistic and archaeological studies made in the twentieth century have shown the austronesian character of the population of Madagascar, while recognizing a Bantu influence. Through the ceramic productions of population of the western Indian ocean, this study examines the penetration of Austronesian cultural influence towards the east African coast, and conversely, the advance of Bantu cultural influence to the Comoros and Madagascar
Dubreuil, Céline. „Variabilité spatio-temporelle de l'ultraplancton dans le secteur indien de l'océan Austral“. Aix-Marseille 2, 2003. http://www.theses.fr/2003AIX22097.
Der volle Inhalt der QuelleBoyer, Montégut Clément de. „Couche mélangée océanique et bilan thermohalin de surface dans l'Océan Indien Nord“. Paris 6, 2005. https://tel.archives-ouvertes.fr/tel-00011449.
Der volle Inhalt der QuelleMichel, Charles. „Les îles Éparses : un avenir à inventer : étude géopolitique de l'espace constitué par les îles Europa, Bassas da India, Juan de Nova, les Glorieuses et Tromelin“. La Réunion, 2004. http://tel.archives-ouvertes.fr/tel-00488929/fr/.
Der volle Inhalt der QuelleRaniriharinosy, Harimanana. „Nations Unies : la poursuite de l'objectif de zone de paix dans l'Océan indien“. Aix-Marseille 3, 2000. http://www.theses.fr/2000AIX32075.
Der volle Inhalt der QuelleFilliozat, Manonmani. „L'océan oriental : connaissances hydrographiques françaises aux XVIIe et XVIIIe siècles“. Paris, EPHE, 2002. http://www.theses.fr/2002EPHE4036.
Der volle Inhalt der QuelleBehagle, Nolwenn. „Structuration acoustique du micronecton de l'écosystème océanique du sud-ouest de l'océan Indien“. Thesis, La Rochelle, 2015. http://www.theses.fr/2015LAROS039/document.
Der volle Inhalt der QuelleTo understand the functioning of an ecosystem, it is essential to understand the organization of its associated food web. While the distribution of primary production and top predators in the Southwest Indian Ocean's oceanic waters (10-60 ° S, 35-90 ° E) are well known, a lack of knowledge remains regarding the distribution of mid-trophic level organisms, despite their ecological (biological pump and key trophic role) and potentially economic (commercial fisheries in the near future) importance. To fill this gap, this work focused on the horizontal and vertical distribution and composition of micronektonic communities in this region. Micronekton comprises relatively small organisms (1 to 20 cm long) able to swim freely without being unduly affected by currents. Micronekton distributions have been studied at meso- and large-scale using acoustic recordings (38 kHz). A vertical structure in three layers has been identified ; the intensity and thickness of these layers vary depending on the considered time period (diel migration) and ocean conditions (meso-scale oceanic eddies and large-scale oceanic fronts). Horizontaly, the Southwestern Indian Ocean harbours the richest waters (10-800 m) in subtropical latitudes in summer and winter times. Since every organism has its own ecological characteristics, it was important to separatly describe the distribution of biological groups composing micronekton. A bi-frequency acoustic approach (38 and 120 kHz) allowed the distinction of micronektonic crustaceans from small mesopelagic gas-filled swimbladder fish in waters east of Kerguelen where micronektonic crustaceans where dominant in terms of overall acoustic density. Two distinct types of vertical structure were highlighted : an aggregative and a layer structure. Micronektonic crustaceans were characterized by layering, day and night, while other organisms (gas-filled swimbladder fish in particular) exhibited structure mixing aggregates and layers during the day, but only composed of layers during the night. In summary, the acoustic approach used in this work helped to describe the distribution and composition of micronektonic organisms and provides an essential knowledge base on the micronekton of the southwest Indian Ocean
Meetoo, Cherina. „Étude des conditions de cyclogénèse tropicale sur le sud-ouest de l'océan Indien“. Toulouse 3, 2014. http://thesesups.ups-tlse.fr/2515/.
Der volle Inhalt der QuelleMature tropical cyclones around the world form through similar atmospheric and oceanic processes. Whereas the necessary conditions for tropical cyclogenesis to occur are identical over all tropical basins, the specific environments within which pre-existing disturbances evolve into warm-core cyclonic circulations can be fairly different. This is partly due to the influence of large-scale climatic cycles (e. G. , ENSO, IOD, etc. ) and synoptic-scale propagating modes (e. G. , equatorial waves, MJO, etc. ). While many studies have examined the specific situations of the tropical basins in the northern hemisphere, storm formation is much less known in the southern hemisphere. This thesis presents an analysis of cyclogenetic evolution of named storms (tropical storms and cyclones) in the Southwestern Indian Ocean (10% of global cyclone activity) during 12 cyclonic seasons from December to March, from 1999-2000 to 2010-2011, based on ECMWF ERA-Interim reanalyses, METEOSAT satellite images and IBTrACS cyclone data, in connection with ENSO, MJO and equatorial waves (Equatorial Rossby, Mixed Rossby- Gravity and Kelvin waves). First, an objective method is used to detect tropical storms (also identified in the IBTrACS database) in the ERA-Interim reanalyses. The overall characteristics of cyclonic perturbations (warm/cold cores, baroclinicity and upper-level forcing) that evolve into tropical storms and cyclones in the SWIO are also discussed. Then, an objective determination of relevant predictors and their associated weight is presented, followed by the determination of their combination in a linear form to derive an environmental cyclogenesis tracker adapted to the SWIO cyclonic season. The various dynamical and thermodynamical environmental parameters that compose the tracker's formula are analyzed spectrally in space and time. The influence of the different wave modes on cyclogenesis is discussed through their impact on the environmental values that play a significant role in cyclogenesis. Finally, numerical simulations of tropical cyclone Alenga (Nov/Dec 2011) are carried out to study the small-scale processes involved in the storm's formation and development within an MJO active phase
Bouquillon, Anne. „Influences continentales et marines dans les sédiments cénozoi͏̈ques de l'Océan Indien Nord Oriental“. Lille 1, 1987. http://www.theses.fr/1987LIL10154.
Der volle Inhalt der QuelleGauvin-Bialecki, Anne. „Étude de cinq éponges de l'océan Indien : contribution chimiotaxonomique, recherche de molécules bioactives“. La Réunion, 1998. http://elgebar.univ-reunion.fr/login?url=http://thesesenligne.univ.run/98_02_Gauvin.pdf.
Der volle Inhalt der QuelleAyouba, Saffaride. „Tourisme et patrimoines. Valorisation et développement de territoires insulaires dans l'océan indien : Mayotte“. Thesis, Normandie, 2018. http://www.theses.fr/2018NORMR138/document.
Der volle Inhalt der QuelleMayotte, the 101st French department, one of the outermost regions (ORs) of the European Union, is a strategic place in the Western Indian Ocean, with one of the largest enclosed lagoons in the World. The island of Mayotte suffers from underdevelopment of infrastructures facilities from poverty and mass immigration from the other Comoros islands, after having rejected independance from France in the 1974 and 1976 referendums. This choice for Mayotte People, which leads to departmentalization in 2011, means an integration to French Republic principles and politics. By targeting territorial development, and hancing the value of a tropical island ressources after the abandonment of the plantation economy makes tourism an opportunity for development. In addition to the lack of accomodation facilities, an image close to the "exotic" expectation is yet missing. Invention and enhancement of Heritage, if not limited to the lagoon, require prior inventories, nowadays dispersed, and then unified by a Heritage making policy. This policy is gradually conducted around a new institution, the Museum of Mayotte (MuMa), a local Museum of Mankind taking in account both natural and cultural environments. These various choices, with first of all the construction of a brand image of Mayotte, then tourism development to enhance this image and making Heritage a tangible resource, engages many debates that can reach conflicts of use and meaning. This is true of both natural and cultural resources. For Why? For What? What to do? The Mahoran identity is torn between the party of irreducible singularity, through religion in particular, colonial Heritage, and that of departmentalization in a "one and indivisible" Republic. The thesis explores this succession of steps towards economic, social and political development, with Heritage as a guide and Culture as core issues
Corbière, Antoine. „Variabilité interannuelle à décennale du cycle océanique du carbone dans le gyre subpolaire de l'Océan Atlantique Nord“. Paris 6, 2008. http://www.theses.fr/2008PA066568.
Der volle Inhalt der QuelleColonna, Michel. „Chronologie des variations du niveau marin au cours du dernier cycle climatique (0-140 000 ans) dans la partie sud occidentale de l'océan Indien“. Aix-Marseille 1, 1994. http://elgebar.univ-reunion.fr/login?url=http://thesesenligne.univ.run/H/Colonna_1994.pdf.
Der volle Inhalt der QuelleTchicou, Richard. „Approche lagrangienne de la diffusion turbulente horizontale : Application au courant circumpolaire au sud de l'océan indien“. Paris, Muséum national d'histoire naturelle, 1998. http://www.theses.fr/1998MNHN0004.
Der volle Inhalt der QuelleRouhan, Germinal. „Systématique phylogénétique du genre Elaphoglossum Schott ex J. Sm (Elaphoglossaceae, Monilophytes) : approches morphologique, moléculaire, et implications biogéographiques pour la région de l'Océan Indien“. Paris, Muséum national d'histoire naturelle, 2005. http://www.theses.fr/2005MNHN0029.
Der volle Inhalt der QuelleElaphoglossum Shott ex J. Sm. (Elaphoglossaceae) is one of the most diversified Monilophyte genera. This great diversity is paradoxically associated to a simple and uniform general morphology. The aim of this thesis is to propose for the first time a supported phylogenetic hypothesis to clarify the taxonomy of the genus. To do that, morphological and molecular characters were analysed from a sample of 123 species. The results confirm the monophyly of the genus and suggest that it contains five well supported main clades. The phylogenetic tree resulting from this analysis was also used to examine biogeography of the genus, especially the origin of species in the Indian Ocean area. Because the genus radiated during the Cenozoic, long-distance dispersal probably best explains sister-group relationships between the diversity center of the Neotropics with the Paleotropical region of the Indian Ocean. Finally, the taxa from the latter region are revised
Fortilus, Jeanne Marie Rose. „Modélisation bioéconomique des pêcheries thonières : mise en place d'aires marines protégées en haute mer de l'Océan indien“. Nantes, 2012. http://www.theses.fr/2012NANT4023.
Der volle Inhalt der QuelleEn introduction de la thèse, j'expose tout d'abord les enjeux biologiques et économiques de la gestion des pêcheries, puis la problématique des aires marines protégées (AMPs), notamment en haute mer. Dans une seconde partie, la description de la structure en réseau du système bioéconomique a été réalisée: des stocks jusqu'aux di#érents marchés. Je présente ensuite comment la prise en compte de cette structure m'a permis d'homogénéiser les données de captures issues de la base de données Sardara et celles de commerce issues de la base de données Fishstat. Je propose alors une analyse succincte des données homogénéisées. Dans la dernière partie de la thèse, je développe un modèle bioéconomique de l'ensemble de la filière. Ce modèle est basé sur la notion d'équilibre de réseau lequel est reconnu comme de grande taille puis qu'il implique environ 1000 liens biologiques ou économiques. Les algorithmes que j'utilise pour le calcul de l'équilibre du réseau tout en itérant le principe sur plusieurs années sont fournis en annexe. Enfin, je montre que ce travail est capable de développer et d'analyser différents scénarii, de la mise en place d'AMPs au large, entre autres, dont les résultats sont analysés avant de conclure
Duflot, Valentin. „Quantification et étude du transport des polluants dans la troposphère tropicale de l'océan Indien“. Phd thesis, Université de la Réunion, 2011. http://tel.archives-ouvertes.fr/tel-00671951.
Der volle Inhalt der QuelleRajaonarivelo, Théogène. „Recherches sur l'établissement d'une coopération entre les îles du Sud-Ouest de l'Océan indien“. Aix-Marseille 3, 1993. http://www.theses.fr/1993AIX32023.
Der volle Inhalt der QuelleOn the 10th january in 1984 in victoria, the signature of the general co-operation agreementby madagascar, mauritius and the seychelles had given birth to the indian ocean commission creation (first international regional setup organisation in this area) and to the establishment of a new inter-islands co-operation. The coi propose for reaching a double objective : to care to institute, in the long term, the integration of the insular economies ; and, in the short and riddle terms, the well-balanced zone countries development. Considering the geographical and political particularity of the indianoceaniq space, the coi has had to research how to set possible degrees of the co-operation and projects selection. In spite of the intellectual value of the commission works, the cooperation had met serious problems with bringing into because of, in the one hand, the unfinished structural organisation's feature of the coi, and on the other hand, the interest conflicts wich oppose its state members. The inter-islands co-operation's future depends on their capa
Lilette, Valérie. „Conservation et patrimonialisation de la tortue marine dans le Sud-Ouest de l'océan Indien“. La Réunion, 2007. http://elgebar.univ-reunion.fr/login?url=http://thesesenligne.univ.run/07_08_Lilette_pap.pdf.
Der volle Inhalt der QuelleThe comparative study of conservation and heritage of marine turtle between Comoros and south-western Madagascar aims at understanding the process of convergence and divergence leading to the success or failure of projects, and the socio-economie changes they imply on a local scale. These conservation projects are based on the environmental ideology thaf focal communities mariage the new regulations. They recommend the development of eco-tourism as a solution to increase the value of natural sites or flagship species that need protection. The motivations of the different parties involved in these projects cain only be understood after reading the internal strategies an the institutions in which they lake part. The comparison of two monographs, Itsamia (Mohéli, Comoros) and Anakao (South-western Madagascar), aims at presenting the economie stakes induced by marine turties (through fishing, eco tourism valuation), and the shift that these events imply (valuation or devaluation of the animal). Maritime, economie and touristy antropology are tools that allow apprehending strategies of territorial assertion, identity reinforcement and emergence of new cultural spaces in coastal communities. The touristic value implies a distance between human and marine turties, thus making us wonder about the relationship we have with nature, locally and globally
Dyment, Jérôme. „Structure et évolution de la lithosphère océanique dans l'océan Indien : apport des anomalies magnétiques“. Université Louis Pasteur (Strasbourg) (1971-2008), 1991. http://www.theses.fr/1991STR13050.
Der volle Inhalt der QuelleAupiais, Dominique. „La part celtique dans l'héritage culturel et politique des comptoirs français de l'océan Indien“. Thesis, La Réunion, 2011. http://www.theses.fr/2011LARE0001/document.
Der volle Inhalt der QuelleFrom the inception of French Orient Company in 1642 to the end of the royal privilege bequeathed to the French East Indian Company in 1767, stretches the French trading post colonial period in the Indian Ocean. During more than one century, hundreds of colonists coming from littoral Brittany, Normans or Poitiers will settle in these outlandish outposts: In Fort Dauphin (Madagascar), in Bourbon Island, in Mahé (India), Chandernagor, Karikal, Yanaon, Isle de France, Rodrigues and the Seychelles. The settlers possess the cultural psyche of their compatriot of western France characterised by a deep celting rooting. Why does the western France possess such a specific feature? Because this part of France has been relatively spared by the many invasions coming from the South and the East of Europe: romanization and germanization. This thesis describes celtism witch was displayed in those regions and it has enriched “indoceanic interculturality”
Chaillou-Atrous, Virginie. „De l'Afrique orientale à l'océan indien occidental, histoire des engagés africains à La Réunion“. Nantes, 2010. http://www.theses.fr/2010NANT3024.
Der volle Inhalt der QuelleAfter the abolition of slavery in 1848, Reunion ne se planters asked for a re-organisation of colonial work and large recourse to a foreign labour force on hiring contract. Facing the constraints of the British government about the French recruitment in India, the authorities from Reunion turned more actively towards the African continent. First limited to the populations that were free originally, this recruitment expanded to captive populations in 1856, as Napoleon authorized hired help by “preliminary ransom” officially. Thus, in the second half of the 19th century, more than 30,000 Africans, especially from Mozambique, emigrated to Reunion to work on sugar plantations. Accomodated in bad conditions, ill-fed and badly considered by the Reunionnese post-slavery society, and submitted to excessive work, most of these workers were never repatriated of their country and entered a process of Creolism. Done in doubtful conditions and often similar to a new form of slave trade, the recruitment of African hired workers in Reunion was spoilt by a series of abuses that led to its prohibition in 1859. Yet by the end of the century, a new context and the pressing need of a workforce launched the negociations with the Portuguese authorities again. The recruitment of hired workers from Mozambique started again in 1887 but under strict regulations. This new wave of immigration was particular due to a slight number of recruitees and mass repatriations after a short stay on the island. Discouraged, the planters definitely stopped their attempts to recruit in Africa at the beginning of the 20th century and progressively resorted to local workforce. ²