Cette thèse constitue une contribution à la modélisation numérique diphasique du transport sédimentaire en milieux côtiers et estuariens. L'approche diphasique diffère de l'approche dite classique en résolvant des équations de conservation de la masse, de la quantité de mouvement et de transport pour l'énergie cinétique turbulente séparément pour chaque phase. Les interactions entre le fluide et les particules sont alors représentées par des termes de transfert entre les deux phases. Le travail présenté dans cette thèse porte essentiellement sur la modélisation de la turbulence dans les écoulements diphasiques fluide particule.<br /><br />En terme de résultats, nous montrons que l'approche développée est capable de reproduire quantitativement les principaux processus mis en jeu dans le transport sédimentaire de particules non cohésives : la sédimentation et la dispersion turbulente des particules en milieu dilué. Le modèle développé confirme l'existence d'une différence de vitesse horizontale entre les particules et l'eau. Il simule les effets de dispersion des particules par le mouvement turbulent du fluide et l'atténuation de l'énergie cinétique turbulente du fluide due à la présence des particules. Une autre originalité de ce travail est de proposer un modèle diphasique à surface libre, bidimensionnel vertical, pour la simulation du transport sédimentaire. Nous avons identifié des lacunes entre les théories et les expériences notamment pour la simulation de la turbulence en écoulement dense. Nous proposons des solutions pour améliorer la simulation du comportement de matériaux cohésifs. Une tentative de simulation hydrosédimentaire sur l'estuaire de la Seine est présentée. Le phénomène de bouchon vaseux est qualitativement reproduit par le modèle sans qu'aucune loi d'érosion ou de dépôt ne soit imposée.

The goal of this thesis was to examine submerged macrophoe biomass, distribution, and ecosystem effects at scales large enough to incorporate the littoral zone into models of whole lake structure and function. Submerged macrophyte biomass and distribution was shown to be highly variable between growing seasons and primarily dependant upon air temperature and the timing of the onset of the growing season. Within a growing season, a mass balance study showed an undisturbed macrophyte bed to markedly lower phytoplankton biomass: total phosphorus ratios, although the net effect of the bed on the growing season phosphorus budget was minimal. The weedbed preferentially retained phytoplankton biomass while being a source of bacterial production to the open water. These findings were mirrored at the among lake scale, as planktonic respiration and bacterial production were higher in macrophyte dominated lakes than would be expected based on phytoplankton biomass alone. Further, phytoplankton biomass was lower than would be expected based on epilimnetic phosphorus levels, showing that the classical view of pelagic interactions that proposes phosphorus determines phytoplankton abundance, which in turn determines bacterial abundance through the production of organic carbon, becomes less relevant as macrophyte cover increases. Long term phosphorus accumulation in the littoral zone was shown to be linked to macrophyte biomass, and on average almost an order of magnitude higher than calculated from the growing season (June--October) phosphorus budget, suggesting that the bulk of phosphorus accumulation in weedbeds occurs outside of the growing season. Finally, sediment core data showed that while submerged weedbeds accumulate up to four times as much bulk sediment compared to the profundal zone, phosphorus accumulation in weedbeds is much less than observed in the profundal zone. These results strongly indicating that submerged macrophyte beds play a central role in trapping ep

[Truncated abstract] The lake boundaries are an important source of sediment, nutrients and chemicals. For life inside the lake, the exchange between the lake boundaries (littoral) and lake interior (pelagic) is of central importance to Limnology as the net flux of nutrients into the water column is both the driving force and limiting factor for most algae blooms found during the stratification period. Consequently, the understanding of the relevant processes defining such an exchange is a further step toward a sound basis for future decisions by lake managers in order to ensure high water quality. The objective of this research was to investigate the physical processes responsible for the exchange of water and particles between the lake boundaries and the lake interior. An integrated approach using field experiments and 3D modelling as applied to Lake Kinneret (Israel) is presented. The field data revealed large-scale metalimnion oscillations with amplitudes up to 10 m in response to westerly diurnal winds, the existence of a well-defined suspended particle intrusion into the metalimnion of the lake, characterized by high concentrations of organic matter, and a well-mixed benthic boundary layer (BBL). The changes in the thermal structure explained the observed vertical and horizontal movements of the suspended particle intrusion. The horizontal advective transport via the metalimnion, associated with the velocities induced by the basin-scale mode-two Poincare wave, controlled the exchange between the lake boundaries and lake interior on daily time scales. The observed BBL over the lake slope varied markedly with time and space. Detailed comparison of simulation results with field data revealed that the model captured the lake hydrodynamics for time scales from hours to days. The model could then be used to extract the residual motions in the various regions of the lake. The residual motions below the surface layer were predominantly forced by the basin-scale internal wave motions, but the residual motion in the surface layer was found to be very sensitive to the curl of the wind field. The residual circulation was responsible for redistributing mass throughout the lake basin on time scales from days to weeks. A clear connection of dynamics of the BBL with the large-scale features of the flow was addressed. The time history of the mixing in the BBL and the resulting cross-shore flux was shown to vary with the phase of the basin-scale internal waves.

Made available in DSpace on 2015-05-07T14:49:15Z (GMT). No. of bitstreams: 0 Previous issue date: 2006-02-21 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / Reef environments attract yearly, a huge influx of tourists and recreationists who relentlessly pursue the leisure and knowledge of marine biodiversity, generating a significant profit for the economy of locales with peculiarities for tourism and recreation. However, the touristicrecreational activity at environmental reefs presents negative implications for local biodiversity if not associated to a planned process, mainly when not interrelated to social, economical, and biological dimensions throughout the planning. The reef environments at the beaches of Seixas, Penha, and Arraial (on southern littoral of João Pessoa, capital of Paraíba state, Northeast Brazil) have a lower touristic-recreational influx as compared to other reefs in the state of Paraíba. However, there is already a timid touristic promotion advertising the reefs of that part of southern littoral of Paraíba, mostly the ones at Penha beach. Therefore, it was aimed in the present dissertation to present a proposal concerning tourism planning and recreation on environmental reefs situated at the above-mentioned beaches, through zoning and evaluation of recreational carrying capacity. Firstly, it was performed a diagnosis of the areas by focusing socio-economic and biological aspects that generated important information for constructing the zoning proposal and estimating the recreational carrying capacity (Cifuentes, 1992). With respect to the biological aspects, it was performed an analysis of the distribution of the cnidofauna (with emphasis on scleractinian corals, zoanthidean, and calcareous hydroids) in areas with and without recreational use, through visual records carried out in October and November 2005. With respect to the socioeconomical aspects, the artisanal fishermen s way of life at the Penha beach was characterized, as well as their perceptions on several subjects, like the reef environments, conservation units, and excluded zones for fishing and tourism, by applying structured interviews as data collection technique which was carried out in June and July 2005. The following cnidarians species were identified: five scleractinians (Siderastrea stellata, Mussismilia harttii, Montastrea cavernosa, Agaricia agaricites and Porites astreoides; four zoanthideans (Palythoa caribaeroum, Protopalythoa variabilis, Zoanthus sociatus, and Zoanthus nymphaeus); and one calcareous hydroid (Millepora alcicornis). A greater biodiversity was observed in the area without recreational use. The fishermen at the Penha beach usually go to the reef areas for fishing and leisure, and they showed to be receptive to tourism and to the proposal for the establishment of a conservation unit in the area. Four zone types were defined for the zoning, with distinct uses and patterns, besides a buffer zone adjacent to the continent, since indirect impacts caused by local human actions may reduce the reefs health. The recreational carrying capacity was established from 26 visits per day or 4,680 per year carried out to the reefs of Seixas beach. It is proposed here a flexible and adjustable touristic-recreational planning for the study area, which might be partly modified throughout time, as new data on local biota, physicochemical parameters, and increase of touristic-recreational influx may come out / Os ambientes recifais atraem, anualmente, um contingente de turistas e recreacionistas ávidos pelo divertimento e conhecimento da biodiversidade marinha, gerando um aporte financeiro significativo para as economias de locais com peculiaridades para o turismo e recreação. No entanto, a atividade turístico-recreativa em ambientes recifais reveste-se de um caráter destrutivo para a biodiversidade local quando desvinculado de um processo de planejamento, sobretudo quando não interrelaciona as dimensões sociais, econômicas e biológicas no transcorrer do planejamento. Os ambientes recifais das praias dos Seixas, Penha e Arraial (litoral sul da cidade de João Pessoa-PB) possuem um fluxo turísticorecreativo inferior ao de outros ambientes recifais da Paraíba. No entanto, já existe uma tímida promoção turística divulgando os recifes da área, sobretudo os da Penha. Assim, o objetivo desta dissertação foi o de apresentar uma proposta de planejamento do turismo e da recreação para os ambientes recifais das praias acima mencionadas, através do zoneamento e da avaliação da capacidade de carga recreativa. Num primeiro momento, o diagnóstico das áreas de estudo fez-se necessário, enfocando aspectos biológicos e sócioeconômicos, que geraram subsídios para a construção da proposta de zoneamento e para a determinação da capacidade de carga recreativa. Com respeito aos aspectos biológicos, foi realizada uma análise da distribuição da cnidofauna (com ênfase nos corais escleractínios, zoantídeos e hidróides calcários) em áreas com e sem uso recreativo, através de registro visual, nos meses de outubro e novembro de 2005. Quanto aos aspectos sócio-econômicos, o modo de vida dos pescadores artesanais da Penha foi caracterizado, bem como suas percepções sobre diversos assuntos, como ambientes recifais, unidades de conservação, zonas de exclusão de pesca e o turismo, utilizando a entrevista estrutura como técnica de coleta de dados, nos meses de junho e julho de 2005. Foram identificadas cinco espécies de corais escleractínios (Siderastrea stellata, Mussismilia harttii, Montastrea cavernosa, Agaricia agaricites e Porites astreoides; quatro de zoantídeos (Palythoa caribaeroum, Protopalythoa variabilis, Zoanthus sociatus, e Zoanthus nymphaeus); e um hidróide calcário (Millepora alcicornis). A maior biodiversidade foi observada na área sem uso recreativo. Os pescadores da Penha utilizam os ambientes recifais para o lazer e a pesca, e se mostraram receptivos ao turismo e a proposta de criação de uma unidade de conservação na área de estudo. Para o zoneamento foram definidos quatro tipos de zonas, com usos e padrões distintos, e uma zona de amortecimento na porção terrestre adjacente, pois os impactos indiretos provocados pela ação humana podem diminuir a saúde dos recifes. A capacidade de carga recreativa foi definida em 26 visitas/dia ou 4.680 anuais para o ambiente recifal da praia dos Seixas. Propõe-se aqui um planejamento flexível, ajustável e passível de ser modificado, ao longo do tempo, com o advento de dados referentes à biota local, aos parâmetros físico-químicos e ao aumento do fluxo turístico-recreativo

Made available in DSpace on 2015-03-13T17:10:36Z (GMT). No. of bitstreams: 1 AdaultoGB.pdf: 2543935 bytes, checksum: f4239d9ee714b76b4513d91d29a379aa (MD5) Previous issue date: 2006-08-25 / Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico / This present work has as its objective the analysis of transformations relating to the production processes in the Southern littoral urban space of the city of Jo?o Pessoa PB. The research estimated that the urban space is the product, means and condition of the society which produces it. The object-area of this inquiry is constituted of five districts: Altiplano Cabo Branco, Portal do Sol, Ponta do Seixas, Penha and Costa do Sol. The urban expansion which occurs in this area is characterized by the appearance of sufficient contradictory space phenomenona. On the other hand, the launching of real estate products such as the horizontal closed condominiums, directed towards the upper class, and the occurrence of areas of irregular occupation, inhabited by lower socioeconomic class and with a great lack of infrastructure and basic urban services, revealing the social contradictions. Due to this, processes such as auto-segregation and segregation imposed beyond the precarious and delinquent inclusion, has become the determining characteristic of this part of the city in analysis. The study also takes into account the appreciation of the new urban environmental zoning of Altiplano do Cabo Branco and from this moment on, start the discussion about the tendencies of urban expansion in this area, due to the interests and strategies of the real estate sector and the prominent role of the government in the current valorization process of urban soil of the area. The presence of residuals of agricultural businesses indicates a typical picture of the peri-urban areas configuring what we observe today at the Southern littoral of Jo?o Pessoa / O presente trabalho tem por objetivo analisar as transforma??es que est?o relacionadas com o processo de produ??o do espa?o urbano no Litoral Sul da cidade de Jo?o Pessoa PB. O estudo parte do pressuposto de que o espa?o urbano ? produto, meio e condi??o da sociedade que o produziu. A ?rea-objeto dessa investiga??o ? constitu?da por cinco bairros: Altiplano Cabo Branco, Portal do Sol, Ponta do Seixas, Penha e Costa do Sol. A expans?o urbana que ocorre nessa ?rea ? caracterizada pela emerg?ncia de fen?menos espaciais bastante contradit?rios. Por seu turno, o lan?amento de produtos imobili?rios como os condom?nios fechados horizontais, voltados para os estratos sociais de elevado poder aquisitivo, e a ocorr?ncia de ?reas de ocupa??o irregular, habitadas por camadas de baixo poder socioecon?mico e com grandes car?ncias de infra-estrutura e servi?os urbanos b?sicos, s?o reveladores das contradi??es sociais. Em fun??o disso, processos como auto-segrega??o e segrega??o imposta, al?m da inclus?o prec?ria ou marginal, tornam-se caracter?sticas marcantes dessa parte da cidade em an?lise. O estudo tamb?m faz uma aprecia??o do novo zoneamento urbano ambiental do Altiplano do Cabo Branco e, a partir dele, discute sobre as tend?ncias da expans?o urbana nessa ?rea, em face dos interesses e estrat?gias do setor imobili?rio e do papel proeminente do Estado no atual processo de valoriza??o do solo urbano da ?rea. A presen?a de res?duos de atividades rurais apontam para um quadro t?pico das ?reas periurbanas, tal como se configura grande parte do Litoral Sul de Jo?o Pessoa

Biodiversity of planktonic crustaceans, cladocerans and copepodans in southbohemian Naděje fishponds system were studied. Both fishpond and non-fishpond (pools, canals, sand-pits, river) localities were observed. Samples were taken from pelagic and littoral zones. Total of 21 species of copepodans and 44 species of cladocerans were recorded over whole area. Hypothesis {\clq}qA higher fish management intensity and higher fish stock cause a lower diversity of zooplankton in a pelagic zone`` was proven. Suppressed species are able to survive in a smaller space (littoral zones, pools, canals, fishponds with a lower fish stock and other non-fishpond localities), where predation pressure is not so strong. None or mild decline of a species diversity can be observed in large areas rich in different water ecosystems, with a reasonable management and production intensity. Different methods of sampling were also compared, those of {\clq}qprolovení litorálních partií`` proved good with the view of effectiveness.

Sand-pits which were formed especially in the floodplain of the Lužnice River since the 1950s currently constitute important landscape element of the Třeboň Basin. My diploma thesis is focused on the assessment of the impact of land use on the former sand-pits in the region of Veselí nad Lužnicí. Field investigations were carried out from the beginning of June till the end of August 2008. I mapped the land use of this area by using a map key. I put down particular areas {--} agricultural areas, forest areas, water areas, bild-up areas, other areas {--} into map photographs. The total area of the mapped territory was 989 hecteres. The biggest part of the area comprises of forest growths and field-grown plants. Water areas (with the main element of the mapped area {--} a system of former sandpits) formed 23% of the total area. On the bank sof the sand-pits were placed phytosociological relevé, which illustrated littoral vegetation and environment in which this vegetation is located, and what is the influence of human activity on vegetation. I placed 74 phytosociological relevé in this system. I recorded 125 plant species {--} out of these were 104 herb plants and 21 woody species. I recorded 41 nitrophilous, 52 wetland, 16 ruderal and 2 stronngly endangered species. Altogether, 20 water samplings were carried out. Horusice I sand-pit is the richest in nutrient, the poorest in nutrients is Horusice sand-pit.

La gestion du domaine public suscite des conflits récurrents en matière d’aménagement, de protection et de mise en valeur du littoral et cela concerne notamment les plages. On aurait pu penser que les instruments de contrôle foncier et patrimonial mis à la disposition des pouvoirs publics étaient assez efficaces pour leur permettre de mener à bien leurs missions. Mais la réglementation en vigueur concernant la gestion du domaine public maritime, et tout particulièrement celles des plages, est loin d’avoir apporté une sécurité juridique suffisante. La législation relative aux plages est confrontée à une insécurité juridique ; la réglementation devient difficile à maîtriser en raison de la complexité des règles et de leur « difficile transposition » dans les départements et régions d’Outre-mer liée à leur caractère insulaire, ce qui a pour conséquence d’obscurcir la loi et de rendre ainsi ineffectif le droit en vigueur. L’objet de la présente étude est de montrer que cette insécurité juridique est aggravée dans les Départements d’Outre-mer, de mesurer l’ineffectivité des règles entourant l’exploitation des plages et d’essayer d’éclaircir cet imbroglio juridique. / The management of the public domain is the root of recurrent problems affecting regional and coastal development, as well as environment al protection including notably the beaches. It Would be obvious to think that the measures taken to maintain a control over the real estate and heritage site put at the authorities disposal were effective enough to enable the carrying out of their mission, but the statements of fact is that the current regulation concerning the maritime public domain and especially the beaches, is not what was expected of it, that means a sufficient juridical security. The real issue is to show firstly, that the legislation concerning the beaches is confronted to a legal insecurity, then demonstrate that the regulation is becoming difficult to master because of the complexity of rules, as well as their tricky transposition in the overseas departments due to the insular nature of these regions. The consequence is the darkening of the law which leads inevitably to its inefficiency. The purpose of this study in to show that this juridical insecurity is worse in the overseas departments, to put also in evidence the ineffectiveness of the rules concerning the exploitation of the beaches, in order to clarify this juridical mess.

L'étude des milieux hétérogènes carbonatés et karstifiés trouve aujourd'hui de nombreuses applications dans les problématiques environnementales, comme la description fine de la structure d'un réservoir côtier, support d'un aquifère affecté par une intrusion d'eau salée. Au sud de l'ile de Majorque (Baléares, Espagne), la plate-forme carbonatée de Llucmajor représente un site privilégié pour ce type d'étude.La caractérisation des hétérogénéités ne peut être réalisée sans une description préalable des propriétés des réservoirs carbonatés et des facteurs modifiant la structure du réservoir. Un des paramètres clés définissant la structure hétérogène est la porosité. Au regard de la large gamme de tailles d'hétérogénéités allant du micromètre à la centaine de mètre, l'utilisation de méthodes multi-échelles est nécessaire.Ce travail de thèse a porté sur la détermination multi-échelles de la porosité, allant de la microporosité à la porosité karstique, et l'établissement de relations entre les changements d'échelles d'observation de ces propriétés. Dans un premier temps, l'application de la microtomographie à rayons X extrait la microporosité et la connectivité des réseaux microporeux. Puis, la tomographie a été utilisée avec une résolution plus faible afin d'étudier le réseau micro- et macroporeux à l'échelle de la carotte. A l'échelle du puits, les images de paroi de puits permettent de déterminer la porosité allant des macropores centimétriques aux karsts. Enfin, la géophysique de surface a permis d'observer l'extension des karsts et hétérogénéités dans une grande partie du site.Ainsi, la structure poreuse du site étudié a été intégrée dans la géologie régionale de la plate-forme. L'observatoire installé sur le site pour surveiller la propagation de l'eau salée dans l'aquifère peut être replacé dans son contexte géologique et pétrophysique, afin d'affiner l'interprétation de ses mesures de variations de salinité. / The study of heterogeneous and karstified carbonates is important in many environmental issues, like the detailed description of a coastal reservoir structure containing an aquifer affected by saline intrusion. At the south of the island of Mallorca (Spain), the Llucmajor carbonate platform represents a typical site for such researches. Characterization of heterogeneities requires a better knowledge of the carbonate reservoir properties and the various factors affecting the structure. One of the key parameters defining the heterogeneous structure is the porosity. According to the wide range of heterogeneity sizes from micrometer to hundreds of meters, the use of multiscale methods is required.This thesis focused on the determination of multiscale porosities from the microporosity to karstic porosity, and of relationships between observation scale changes of these properties. Firstly, the application of X-ray microtomography allows to extract the microporosity and the microporous network connectivity. Then, X-ray tomography was used with a lower resolution to study the micro- and macro-porous network at the core scale. At the borehole scale, the borehole wall images are used to determinate macrostructures from centimeter pores to karsts. Finally, surface geophysics allows to observe the extension of karst and heterogeneities at the site scale.Finally, the porous structure of the study site is integrated into the regional geology of the platform. A hydrogeophysical observatory was installed on site to monitor the spreading of salt water in the aquifer. The interpretation of its salinity measurements can take into account the geological and petrophysical context.

Après les catastrophes territoriales que le Mexique a subies au cours du XIXème siècle, le législateur mexicain a imposé une série de restrictions sévères sur la possession et la propriété des biens immobiliers sur les côtes et les frontières. Ces restrictions sont décrites dans l'article 27 de la Constitution Politique des États-Unis Mexicains, où il est signalé qu'aucun étranger ne peut avoir domaine directe de la terre dans une bande couvrant cinquante kilomètres de la côte et cent kilomètres de la frontière. Historiquement, toutefois, la propriété étrangère dans la zone restreinte a été toléré et même encouragé par des mécanismes juridiques tels que le fidéicommis sur des biens immobiliers en zone restreinte et les sociétés commerciales, de sorte que maintenant la côte mexicaine, particulièrement la péninsule de la Basse Californie, est dans un processus de reterritorialisation qui fait que tous les jours la terre passe aux mains d'étrangers et les côtes deviennent une zone d'exclusion. À travers de cette étude interdisciplinaire, on essayera de comprendre l'impact de ce processus sur la société péninsulaire et l'évolution du phénomène migratoire Nord-Sud qui se produit au Mexique. / After the territorial disaster Mexico suffered during the nineteenth century, the Mexican legislature imposed a series of tough restrictions on the possession and ownership of real estate both on coasts and borders. These restrictions are stated in the Article 27 of the Political Constitution of the Mexican United States. This Article stipules that no foreigner can have direct ownership of land in a strip comprising fifty kilometers from the shoreline and one hundred kilometers from the border. Historically, however, foreign ownership in restricted zones has been tolerated and even encouraged through legal mechanisms such as the Trust for Real Estate in the Restricted Zone and through Corporations. As a result of this, now, the Mexican coast, particularly in the peninsula of Baja California, is in a process of re territorialization. During this process, the land becomes property of foreigners and the coasts become Zone of Exclusion. Through an interdisciplinary study, we will try to understand the effects that this process has on the peninsular society and the evolution of the North -South migration phenomenon that occurs in Mexico. / Tras los desastres territoriales que México sufrió durante el siglo XIX, el legislador mexicano impuso una serie de fuertes restricciones a la posesión y propiedad de bienes inmuebles tanto en costas como en fronteras. Estas restricciones se encuentran señaladas en el artículo 27 de la Constitución Política de los Estados Unidos Mexicanos, en donde se estipula que ningún extranjero podrá tener dominio directo de la tierra en una franja que abarca cincuenta kilómetros a partir de la línea costera y cien kilómetros a partir de la línea fronteriza. Sin embargo, históricamente la propiedad extranjera en zona restringida ha sido tolerada e incluso fomentada a través de mecanismos jurídicos como el Fideicomiso de Bienes Inmuebles en Zona Restringida y las Sociedades Mercantiles, de tal manera que actualmente el litoral mexicano, en particular el de la península de Baja California, se encuentra en un proceso de reterritorialización al pasar cotidianamente a manos de extranjeros y convertirse las costas en zona de exclusión. A través de un estudio interdisciplinario se intentarán comprender los efectos que este proceso tiene sobre la sociedad peninsular así como la evolución del fenómeno migratorio Norte-Sur que se presenta en México.