Dissertations / Theses on the topic 'Écologie des rivages – Tunisie'
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Chaabane, Abdelaziz. "Etude de la végétation du littoral septentrional de Tunisie : typologie, syntaxonomie et éléments d'aménagement." Aix-Marseille 3, 1993. http://www.theses.fr/1993AIX30058.
Full textFourt, Maïa. "Histoire de la pêche des éponges en Méditerranée et son adaptation récente au changement régional." Thesis, Aix-Marseille, 2019. http://theses.univ-amu.fr.lama.univ-amu.fr/191217_FOURT_178pyka634dl637hqgt642gcc_TH.pdf.
Full textIn the Mediterranean Sea, small scale fisheries are firmly anchored in the culture of this maritime area. Sponge fishing has been practiced in the Mediterranean since antiquity. Although contributing to an important exportation market until the mid-20th century, it has recently shown signs of weakness, leading to the collapse of the overall production. This study proposed an interdisciplinary approach applied to over two centuries of sponge fishing history. The first part of this study presents a spatial analysis of the fishery at the Mediterranean scale, considering several key periods in order to identify geographical areas where important changes have occurred. The second part analyses the sponge production and the fishing effort variations in the Aegean area and in Tunisia. The last part of this work is dedicated to an analysis of the fishermen’s adaptive choices faced to the sponge fishing activity upheavals. The study shows that up to the 1970s the factors that influenced this fishery were mainly the societal demand, the fragile economic situation of the fishing communities, changes in uses, as well as the socio-political and economic relationships between Mediterranean countries. Since 1986, frequent epizootic events related to changes in thermal regimes have weakened the sponge stocks. Remaining fishermen have mainly adapted to the irregular availability of the resource by targeting other species, or by relying more on other already existing fishing activities
Hattab, Tarek. "Impacts du changement global sur les assemblages d’espèces exploitées sud méditerranéens, application au golfe de Gabès (Tunisie) : de la modélisation des niches aux conséquences trophiques." Thesis, Montpellier 2, 2014. http://www.theses.fr/2014MON20041/document.
Full textThe Mediterranean Sea is a marine biodiversity hot spot highly affected by several sources of disturbances interacting synergistically: global warming, habitat loss and overfishing threaten marine biodiversity and disrupt the ecosystem balance. To ensure a sustainable management of coastal marine ecosystems according to the Ecosystem Approach to Fisheries, it is necessary to study the ecosystem responses to these disturbances. However, despite the variety of global change studies in Mediterranean areas, ecosystems responses to these changes remain poorly understood and particularly at the southern part of the Mediterranean Sea. In this PhD thesis, the Gulf of Gabes was chosen as study area since it is one of the most affected regions by global change which makes it a mesocosm model of more regional patterns that occur in the Mediterranean Sea. In this study, as a first step, we replaced the Gulf of Gabes in its biogeographic and ecosystem regional context. This was achievied through a phylogenetic-based delineation of biogeographical species pools of coastal Mediterranean fishes and using an ecosystem model to describe its structure and functioning in comparison with other Mediterranean ecosystem model properties. We therefore projected potential future geographic ranges and assemblages composition of biogeographical exploited species pool according to global warming and habitat loss scenarios. Then we assessed their effects on food web structure. Taking into account the taxonomy and inter-species evolutionary relationships, we generate a new bioregionalisation of the continental shelf based on the turnover of lineages. Our results showed that climate is the major driver of species distribution and assemblage's composition. In addition, the exploration of phylogenetic dissimilarity across the Tunisian coast highlighted four major biogeographic areas showing a low spatial congruence with zoning used for fisheries management in Tunisia.Projected range shifts of the 60 main exploited species of the Gulf of Gabes through the implementation of a new climate model (NEMOMED8) revealed that, by the end of the century, 34 species could contract their ranges including 12 species that could become locally extinct across the Gulf of Gabes. Furthermore, by combining Posidonia meadows loss scenarios and climate change projections, our results showed that the magnitudes of the changes range induced by climate change are larger than those resulting from the loss of habitat.The Ecopath mass-balance model allowed us to describe the structure and functioning of the ecosystem of the Gulf of Gabes in comparison with other Mediterranean ecosystems. These models encompass the entire trophic spectrum from phytoplankton to higher trophic levels as well as the main fishing activities in the area. The model results showed that, among the fishing activities studied, bottom trawling was identified as the activity having the widest-ranging impacts across the different functional groups and the largest impacts on some commercially-targeted demersal fish species. Finally, to study the effects of species range shift on food web structure, we used a new methodology to infer trophic interactions between species. Based on the robust relationship between the size of prey and predators, we predicted the current food webs and project potential changes in their structures. We found that a significant portion of the Gulf of Gabes would face an increase of connectance and an extension of trophic pathways in parallel with a decrease in the number of prey per predator and the number of predators per prey. This PhD thesis paves the way towards the understanding of the role of biodiversity in maintaining ecosystem functioning
Perez, Thierry. "Qualité de l'environnement marin littoral : Etude des spongiaires pour la bioévaluation des peuplements de substrats durs." Aix-Marseille 2, 2001. http://www.theses.fr/2001AIX22001.
Full textCorre, Sophie. "Contribution à l'étude des peuplements bactériens des écosystèmes littoraux : les bactéries épiphytes de la Phéophycée Laminaria digitata." Brest, 1991. http://www.theses.fr/1991BRES2030.
Full textBensoussan, Nathaniel. "Choix des échelles de temps pertinentes et développements instrumentaux complémentaires pour une approche intégrée du fonctionnement de communautés littorales." Aix-Marseille 2, 2004. http://theses.univ-amu.fr.lama.univ-amu.fr/2004AIX22102.pdf.
Full textThe questions of the relevant time strategies and ways to access key parameters (CO2-bicarbonates-carbonates system) to study the functionning of littoral communities were examined. The analysis, of a semi-continuous time-series conducted in a shallow NW Mediterranean cove allowed to document the variability, at different time scales (hour, day, season, year), of environmental parameters and O2. Community gross primary production and respiration, high due to the activity of macrophytes, and their variability were examined. An instrument for in situ automatic measurements of pH and Total Alkalinity was developped and deployed at the study site to estimate the contribution of community metabolism (organic and inorganic C metabolism) to the C cycle. The variability of phytoplaktonic activity, studied by means of a module for in situ semi-continuous measurement, was also studied
Darnaude, Audrey. "Apports fluviaux en zone côtière et réseaux trophiques marins benthiques : Transfert de matière organique particulaire terrigène jusqu'aux poissons plats au large du Rh^one." Aix-Marseille 2, 2003. http://www.theses.fr/2003AIX22025.
Full textHasnaoui, Brahim. "Chênaies du nord de la Tunisie : écologie et régénération." Aix-Marseille 1, 1992. http://www.theses.fr/1992AIX11048.
Full textKhemiri, Abdallah. "Rapports entre populations d'abeilles (Apis mellifera intermissa V. Buttel. Reepen) et milieu en Kroumirie (Tunisie du Nord Ouest)." Aix-Marseille 1, 1993. http://www.theses.fr/1993AIX11059.
Full textKhebour, Allouche Faiza. "Éthologie du paysage : contribution à l’étude des changements d’états des paysages de la Dorsale Tunisienne et du Cap Bon." Toulouse 2, 2007. http://www.theses.fr/2007TOU20005.
Full textThese thesis deals with the changement Meditarranean surroundings states. Three small Tunisian Dorsal and Cap Bon basin banks of mediterranean climate : sub-humid, semi-arid and arid are under study. The first chapter is devoted to a regional presentation through the study of the organisation and the evolution of dorsal landscapes taking into consideration the climate, the relief and human interventions. Chapter two highlights the examination of seasonal conditions changements mainly according to climatic factors. A monthly follow-up between october 2002 and october 2003 is brought about in fifteen resorts. Typological analysis and hyrodynamic interpretation contribute to the determination of seasonal conditions chronology. Chapter three stresses the study of plurianual conditions chagements inquired at farmers. The changements stretch over about thirty years (1956-2003). The collected elements involving 244 parcels and their statistical treatments have led to the defination of pluriannual states chronics. The outcome of this study allows the definition of many new concepts about landscape ethology which are compared to those obtained in Caucasus and Senegal
Fehri, Noômène. "Les rapports entre les processus morphogéniques et les pratiques agro-pastorales dans la plaine oléicole de Sfax : exemple du bassin versant de l'oued Chaal-Tarfaoui (Plaine de Sfax, Tunisie centro-orientale)." Aix-Marseille 1, 2003. http://www.theses.fr/2003AIX10103.
Full textBrithmer, Ronald. "Approche écologique de la gestion des ressources naturelles sur le littoral : exemples de la Martinique." Bordeaux 3, 1994. http://www.theses.fr/1994BOR30037.
Full textThis thesis aims to study the coast line of martinique. It's got two essential purposes. - in a first time to study the ecological parameters (ground, climate) which govern the installation of the different environments encountered on the coastline. - in a second time to make some proposals in order to manage the natural resources. So, this document in structured in four parts : - a report as an "inventory of fixtures" of the coastline of martinique. It develops the physical aspects as well as the human resources. - some technical uses of the ecological and above all clematic given informations in order to have a thematic cartograph y of the island and to clonclude a bioclimatic map of this department. - two concrete practices regarding the management of the naturel resources : an approach of the legislature concerning the surroundings of the coastline to be protected and the forestation of some cleaned areas from endermic vegetable species. - some perspective to manage and follow up the natural resources from the use of satellite pictures spot
David, Arthur. "Détection des perturbateurs endocriniens dans les milieux aquatiques littoraux par l'étude des sédiments, moules et préleveurs passifs : apport de l'outil analytique et des modèles cellulaires." Montpellier 1, 2009. http://www.theses.fr/2009MON13505.
Full textMany organic pollutants issued from different sources are present into freshwater and coastal waters. Since these lipophilic contaminants are present at trace levels in water, accumulator compartments such as sediments, passive samplers (semipermeable membrane devices) and mussels can be used to assess their concentration in aquatic systems. It is known that some organic pollutants can disrupt the endocrine system of humans and biota by binding the estrogen receptor (ER). Detection of endocrine disruptors (ED) can thus be performed using in vitro bioassays which expressed the ER. These bioassays give informations on the global activity of environmental samples while chemical analysis can be be used in order to identify chemicals responsable of the observed activity. The objective of the thesis was to determine the feasibility and the relevance of using bioessays on various types of environmental extracts (mussels, sediments, passive samplers) to report the level of organic contamination of diverse Mediterranean aquatic systems (river, coastal lagoon, submarine outfall). The Lez River and its coastal environment were selected as case study to estimate the impact of the sewage treatment process (STP) discharge in the particular context of the small Mediterranean rivers. The results of the bioessays and the chemical analysis clearly showed the impact of the wastewater discharge. High concentrations of aromatic polycyclic hydrocarbons and alkylphenols were measured into sediments that were sampled downstream the STP outlet and into coastal lagoons. The study of the distribution of ED between mussels, sediment and passive samplers in the coastal lagoons clearly showed the role of sediment in the contamination of the water column. Finally, combination of bioassays and chemical analysis were satisafactory to assess the environmental contamination by EDs
Morschel, Jean. "L'eau et les paysages dans la Dorsale Tunisienne : expliquer le cheminement des flux hydriques en fonction des organisations présentes dans le milieu naturel." Nice, 2006. https://tel.archives-ouvertes.fr/tel-00532885.
Full textSeveral hydrological models are currently in use for predicting floods at the catchment outlet. These vary from lumped rainfall-runoff models which ignore flow processes in the catchment to distributed process-based models which attempt to quantify lateral and vertical fluxes. Few of these models integrate extensive field work and most are based almost entirely on readily available digital data. However flow processes are strongly affected by linear features (paths, roads, hedges. . . ) which are not easily detectable on most digital supports and by factors such as surface roughness or soil depth for which there is often no real data. In the approach described in this Thesis, the catchment was subdivided into landscape segments based on field mapping. These units represent homogeneous morpho-dynamic units that govern vertical and lateral fluxes of water and soil. The Thesis describes the method used for creating the units and landscape segments which will be used for quantifying both runoff and soil erosion
Bendali, Frédéric. "Dynamique de la végétation et mobilité du sable en Jeffara tunisienne." Montpellier 2, 1987. http://www.theses.fr/1987MON20255.
Full textZakhia, Frédéric. "Diversité des bactéries hôtes de légumineuses méditerranéennes en Tunisie et au Liban." Montpellier 2, 2004. http://www.theses.fr/2004MON20006.
Full textEl, Khorchani Ali. "Approche dendrochronologique de l'influence des changements climatiques sur la productivité des forêts de pin d'Alep (Pinus halepensis Mill. ) en Tunisie." Aix-Marseille 3, 2006. http://www.theses.fr/2006AIX30037.
Full textThe study of Aleppo pine reaction to interannual climate variations makes it possible to specify its ecology and to predict its future productivity in the context of climate change. Nineteen Aleppo pine stands, sampled from humid to arid bioclimate were the subject of a dendroecologic study based on the relation climate-tree ring (ring-width, wood density). For each stand, using radial growth and actual climate data made it possible to calibrate two statistical growth models. Using simulated climate data according to 2x CO2 made it possible to predict future Aleppo pine growth. A statistical model that stands on simple climate parameters (precipitation, temperatures) simulates a strong growth decrease (up to 100% in arid bioclimate) that is linked with precipitation decrease and spring temperature increase. A bioclimatic model that stands on water balance parameters (actual evapotranspiration) simulates an average growth decrease (20%) that is linked with spring and summer water stress increase. The study of Aleppo pine productivity trend evidences both a strong radial growth decrease (50%) and a earlywood density increase (20%) during the second half of the 20th century. Comparing these results with predictions resulting from both models shows that Aleppo pine survival at its southern limit (arid bioclimate) is threatened by the future climate changes
Savoye, Nicolas. "Origine et transfert de la matière organique particulaire dans les écosystèmes littoraux macrotidaux." Brest, 2001. http://www.theses.fr/2001BRES2034.
Full textOuerchfani, Wafa. "La vulgarisation écologique dans le paysage médiatique tunisien." Paris 13, 2008. http://www.theses.fr/2008PA131018.
Full textElloumi, Jannet. "Distribution et rôle des microorganismes de la boucle microbienne dans la saline de Sfax : contribution à l'étude du fonctionnement microbiologique d'un milieu extrême." Clermont-Ferrand 2, 2006. http://www.theses.fr/2006CLF21639.
Full textMchergui, Chokri. "Restauration écologique dans un système estuarien fortement anthropisé : applications au compartiment sol des écotones rivulaires et aux marais alluvionnaires de la Basse Vallée de Seine." Rouen, 2014. http://www.theses.fr/2014ROUES045.
Full textThe first part of the thesis is devoted to diagnose the current state (morphology and functioning) of soils in riparian ecosystems and follow their potential capacity to remove nitrogen during experiments microcosms. The main results of morphology and functional measurements (in situ and ex situ) show that soils in riparian ecosystems cannot be grouped according to their degree of connectivity. Functional measurements showed that low connected sites remains favorable to the sink of carbon and nitrogen removal. Then, I assessed the effect of flood duration due to the daily water fluctuation versus river floods on N removal in riparian soils, a microbially-mediated soil process, through two experiments studies. The first of two studies showed that the daily water fluctuation has a significant effect on the improvement of purifying capacity of soils. The second study showed that disconnected soils have found their normal functions after a change of water regime. Also, it suggests that between 3- and 7-day long waterlogging is needed in the disconnected soils for it to exhibit a significant denitrification level. The second part of the thesis focused in the evaluation of success of the restoration experience following the filling of gravel-pit using dredged sediments. Overall, the results obtained in this part show that (1) the diachronic monitoring of soil characteristics is not efficient to assess if typical wetland soil characteristics are reached in reconstituted soils in a short duration of follow and (2) the functional approach (in situ and ex situ) relative to soil respiration, mineralization of C and N and denitrification appear to be a good tool for evaluating
Morvan, Julie. "Foraminifères benthiques de l'Estran de la baie de Bourgneuf : variabilités spatiale et temporelle : utilisation en tant que bio-indicteurs après une pollution par hydrocarbures." Angers, 2006. http://www.theses.fr/2006ANGE0046.
Full textThe study of the spatial and temporal distribution of benthic foraminifera at different scales has allowed us to better define their ecology in the salt marshes of the bay of Bourgneuf, Vendée (France). Our results show a very variability of faunal density and composition in response to the meteorological conditions, the physico-chemical properties of the seawater and the sediment characteristics (organic matter content, topography, grain size). In 1999, this bay was affected by the Erika oil spill. Benthic foraminifers are commonly used as bio-indicators of oil pollution because they react rapidly to environmental changes. The assessment of the potential impact of this pollution is based on a spatial and temporal monitoring at three sites since january 2000 to july 2004. Very low densities have been observed during at least 21 months after the first arrival of oil. It can not be proved that these exceptionally low standing stocks are due to the toxicity of the oil. We think that the mechanical cleaning of the most polluted sites, an indirect consequence of the Erika oil spill, may have contributed considerably to create a stressed environment for the foraminiferal faunas. In the laboratory, experiments were performed to evaluate foraminiferal responses submitted to Erika oil. The addition of solutions of pollutants caused strongly increasing mortality, but in some cases also reproductive events. In experiments with very high contents of the pollutant, morphological and cytological abnormalities were observed
Tafer, Boulares. "Etude phyto-écologique et syndynamique des complexes de végétation halophile de la plaine de Mohammadia (Macta Oranie) Algérie." Aix-Marseille 3, 1993. http://www.theses.fr/1993AIX30061.
Full textLozachmeur, Olivier. "La consécration du concept de "gestion intégrée des zones côtières" en droit international, communautaire et national." Nantes, 2004. http://www.theses.fr/2004NANT4012.
Full text"Integrated coastal zone management" (ICZM) is a dynamic process in which a coordinated strategy is developed and implemented for the allocation of environment, socio-cultural and institutional resources to achieve the conservation and sustainable multiple use of the coastal zone. After its recognition during the Rio Conference in 1992, the concept was took up by the international community and international organisations. In Europe, this approach was made concrete by the publication of a European strategy of ICZM in 2000 and by a Recommendation to the states members in 2002. Following the dedication of the ICZM concept by the french Government in 2001 and by the french Parliament in 2002, France prepare a national ICZM strategy since 2003. So certain instruments (SMVM, DTA, SDAGE, SAGE, bay contracts. . . ) fit partially in a prospect for ICZM, many efforts and legal adaptation still remain to make so that this concept is truly implemented in our country
Jauffret, Sandrine. "Validation et comparaison de divers indicateurs des changements à long term dans les écosystèmes méditerranéens arides : application au suivi de la désertification dans le Sud tunisien." Aix-Marseille 3, 2001. http://www.theses.fr/2001AIX30066.
Full textAs many rangelands surrounding the Mediterranean Basin, the Tunisian arid zone, characterised by scattered steppic vegetation, is commonly viewed as degraded landscapes. In Arid Mediterranean regions, vegetation dynamics is indeed affected by hunian and non-human disturbances and stresses which induce desertification processes. In this context, the objectives of this research were to identify and validate various indicators of long term changes to provide information useful for the management of arid lands. The study is focussed on the understanding of 1) the structure and functioning of ecosystems and 2) the changes that occur in space and time in response to degradation. The ecological indicators allow us to describe different organisation levels from species to the ecosystem and the landscape. The diachronic comparison of vegetation maps of 1975 and 2000 allow a more complete diagnosis about the evolution of ecosystems and landscapes over the last three decades. .
Supangat, Agus. "Contribution à l'étude biogéologique du domaine paralique indonésien." Montpellier 2, 1996. http://www.theses.fr/1996MON20158.
Full textMialhe, François. "Le développement de l'aquaculture saumâtre dans l'Aire Pacifique : évolution des paysages, dynamiques socio-économiques et impacts environnementaux dans deux territoires au Pérou et aux Philippines." Paris 7, 2010. http://www.theses.fr/2010PA070077.
Full textBased on two case studies in the Philippines (Pampanga) and Peru (Tumbes), the goal of this thesis was to analyze the development of aquaculture with an emphasis on the initial causes of aquaculture, its history, its spatial development, and on its socioeconomic impacts at a range of space and time scales. The methodology associates satellite image processing with fieldwork. Several pond mapping methods based on a combination of multispectral classification techniques and mathematical morphology were tested and compared. Field investigation methods involved questionnaires, interviews, harvesting of second-hand data, direct observation, and a participation in daily activities of various stakeholders. Finally, I crafted a multi-agent model based on empirical data collected in the Pampanga delta with the aim of exploring the influence of a range of environmental and social parameters on landscape evolution
Rambinintsaotra, Saholy Harinirina. "Vers la gestion intégrée des zônes côtières à Madagascar." Limoges, 2006. http://www.theses.fr/2006LIMO0512.
Full textThe coastal zones occupy a very important place in the human's life. They represent, like forests and the agricultural areas, the systems that maintained life on earth. The coastal zones biodiversity contain very weak ecosystems, which mostly suffer from human pressures. Facing this wealth, the different pressures on the coastal territories and the many legal texts that organize this space, the concept of integrated coastal zones management is recommanded by the international instruments. It is mainly the 17th Chapter of the Action plan 21, adopted by the United Nations Conference on Environment and Development (UNCED) organized in Rio in june 1992 which is the basis of this system. The interest of these global and integrated solutions causes a big capacity of adaptation concerning all the different concepts that are led. The main question is to know if the Malagasy legal setting is able to face the changes required by this concept of global management. In relation to the different conflicts that exist on the coastal space, many opportunities offered by the integration of the modern and the traditional right appear, in order to implement the integrated coastal zones management' approach in the country
Hamdi, Ali. "Eléments pour l'éducation relative à l'environnement : étude de l'évolution conceptuelle et des attitudes chez les élèves tunisiens de la deuxième année secondaire à travers leurs conceptions sur l'écosystème forestier." Dijon, 2007. http://www.theses.fr/2007DIJOL035.
Full textFaucher, Christine. "Écologie dynamique d'une plage de sable fin, St-Michel-en-Grève, après la pollution pétrolière de l'"Amoco-Cadiz"." Brest, 1986. http://www.theses.fr/1986BRES0011.
Full textDuport, Eric Marc Yann. "Quantification de la bioturbation dans les écosystèmes marins côtiers : caractérisation des groupes fonctionnels responsables du remaniement sédimentaire." Aix-Marseille 2, 2006. http://theses.univ-amu.fr.lama.univ-amu.fr/2006AIX22054.pdf.
Full textIn order to define the biological and environmental factors playing a role in the sediment reworking intensity changes, works have been carried out both on monospecific Nereis diversicolor population (in vitro) and in situ macrobenthic communities. The studies about in situ communities were realised over time in contrasted Mediterranean environments : St. Antoine canal (Gulf of Fos) and Thau Lagoon. The first part of this work was to characterize the species and more particularly their belonging bioturbation functional group according to their tropic and locomotive behaviors. In the second part, using particle tracers (luminophores), intensity of sediment reworking induced by organisms was quantified. The impact of the different studied factors on sediment reworking intensity was assessed with 1-D model. The results of the in vitro experiment showed the existence of a non-linear relationship between density of gallery-diffusor N. Diversicolor and sediment reworking intensity. The intensity of biodiffusive transport (Db) and the biotransport (r) first increased with the density and then reached a maximal value. This experimentation showed the importance of the population density which appears as a key factor in the sedimentary ecosystem functioning. The studies related to in situ communities allowed to highlight the crucial importance of the species functional traits and the functional diversity of the communities on the sediment mixing dynamics. This work has enabled us to show that temporal changes in sediment reworking are a complex phenomenon which can be explain by combined influence of biological factors (functional composition and density of the community), associated with the direct and indirect influence of environmental (temperature of water, oxygen concentration in the sediments, organic quantity of matter in the sedimentary column and particle size)
Hedi, Abdeljabbar. "Biodiversité des bactéries halophiles de Chotts et Sebkhas tunisiens et applications biotechnologiques." Aix-Marseille 1, 2009. http://theses.univ-amu.fr.lama.univ-amu.fr/2009AIX11034.pdf.
Full textHypersaline environments are found in a wide variety of aquatic and terrestrial ecosystems. Bacterial aerobic communities were recovered from sediments of the shallow salt lake of the hypersalins environments and their distribution with respect to salinity gradients was established. The north and south of Tunisia consists of numerous ecosystems including extreme environments in which the microbial diversity has not been studied. We isolated the bacterial and archaeal communities in the shallow salt lake (El-Djerid and Sebkhas) and their distribution with respect to different physico-chemical characteristics like salinity gradients was established. The characterization was performed by using phenotypic characters including morphological, physiological, biochemical, nutritional test and phylogenetic approaches. Due to the economic importance of salt obtained from this lake, a microbial survey has been conducted. Physico-chemical analysis showed that the salts contain sufficient ions and hardness to support extremely halophilic bacteria. The salt collected from the lake contained a microbial community well adapted to the specific physical and nutritional conditions of each site. The results of analyses were quite similar and demonstrated the phenotypic heterogeneity of the species in question. Extreme bacteria were recovered from sampling sites, which contained up to 250 g/l NaCl. Results of this study were discussed with regard to the ecological significance of these microorganisms in the breakdown of organic matter in hypersalins environments together with the potential use of them in the industry. The purpose of this research was to examine their phenotypic features and their physiological and biochemical characteristics with the aim to screen for metabolites of industrial interest produced by the novel halophilic isolates. A new halophilic anaerobe was isolated from the hypersaline surface sediments of El-Djerid Chott, Tunisia. The isolate, designated as strain 6SANG, grew at NaCl concentrations ranging from 14 to 30%. Based on phenotypic and phylogenetic characteristics, we propose that this bacterium be classified as a novel species of a novel genus, Halanaerobaculum
Dufresne, Carine. "Les risques de disparition d'écosystèmes littoraux en Méditerranée : analyse prospective dans les Alpes-Maritimes et en Ligurie : thèse." Nice, 2004. http://www.theses.fr/2004NICE2026.
Full textThe human activities are intense on the Mediterranean coast and oblige the ecosystems to maintain a favourable stability for their development. The man proposes a partial or total conservation of their specificities but some threats persist. The analysis of the disappearance risks, with the prospective approach of the scenarios, is interesting to do for the ecosystems of Posidonia and of Caulerpa in Alpes-Maritimes and Ligurie. This method detects the principal components in the evolution of the ecosystems and the essential components for the proposition of the future strategies
Jeanson, Matthieu. "Morphodynamique du littoral de Mayotte : des processus au reseau de surveillance." Littoral, 2009. https://tel.archives-ouvertes.fr/tel-00449987.
Full textMayotte Island is characterised by a vast reef-lagoon complex comprising significant mangrove development. Several field experiments involving hydrodynamic measurements, topographic surveys, and observations were coupled with the analysis of aerial photographs in order to gain a better understanding of the evolution of the reef-lagoon complex and of the morphodynamic interactions. The results highlight a remarkably variable mangrove system subject to progression or stability in the north and east of the island, but exhibiting a clearly regressive pattern along the southern and western shores. The hydrodynamic data acquired during the field experiments clearly bring out the spatial and temporal variations in wave and mean current patterns involved in these differences. These data also throw light on the short-term morphodynamics of the small pocket beaches associated with some of these mangroves. The degree of exposure to waves, and reef structure, notably in terms of width and elevation relative to the tidal frame, have a determining influence on the afore-mentioned variations in mangrove dynamics along the shores of the island, and in the greater vulnerability of the mangrove shores of the south and west of the island, especially in the face of strong impinging development pressures. The extermination of these mangrove systems leads to a reorganisation of the sediment stocks and the emergence of new shoreline morphodynamic patterns. These changes have necessitated the construction of an operational observatory aimed at monitoring the coastal dynamics. This tool is based on a network sourced by the measurements and field observations integrated into a GIS
Ba, Antoine. "Télédétection par analyse de retours d’onde LIDAR et spectrométrie à hautes résolutions des espaces sensibles en environnement côtier." Thesis, Nantes, 2017. http://www.theses.fr/2017NANT4040/document.
Full textCoastal dunes are ecosystems of high ecological interest as well as coastal defenses against marinerelated hazards, especially in the current climate change and coastal erosion context. The understanding of dune morphology and the dynamics of its components allows to apprehend its functioning and enables to provide a pertinent and durable coastal zone management. The hyperspectral imagery is a technique allowing the passive observation of optical properties of a surface scene constituents. This method is particularly adapted for covering large geographical areas, with an appropriate spatial scale for observing the coastal features. The LiDAR (Light Detection And Ranging) remote sensing is an active method measuring the Earth’s topography. The full-waveform LiDAR, in addition to provide data on the surface elevation, allows to acquire data on the density and light diffusion power of an observed scene features. Therefore, simultaneous acquisition of both data types should improve the monitoring of Earth’s surfaces. In order to compare and process the data from both types of remote sensing method, a pre-processing step of geometric and radiometric corrections should be applied to the hyperspectral images and full-waveform LiDAR data. Following this step, two applications on the hyperspectral/LiDAR data coupling were developed for the estimation on the vegetation distribution over two coastal dunes systems on the island of Noirmoutier, Vendée, France. The first application built up a mapping methodology for the dune vegetation, from a habitat to a specie scale, in order to discuss the species distribution as well as assessing their impact on the dune morphology evolution. The second application, a complete procedure of vegetation habitats was developed, combining the chemical and the light diffusion properties of the dune surfaces
Brun, Stéphane. "De l'erg à la forêt : dynamique des unités paysagères d'un boisement en région littorale : forêt des dunes de Menzel Belgacem, Cap Bon, Tunisie." Paris 4, 2006. http://www.theses.paris-sorbonne.fr/brun/paris4/2006/brun/html/index-frames.html.
Full textIn the Cap Bon peninsula, located in the north-eastern Tunisia, the forestation of the Menzel Belgacem's dunes constitutes one of the first attempt of forest creating during the French protectorate. From 1930, sands have been gradually stabilized and today the new forest came over the sand deposits. The Dar Chichou's forest, more than 6000 adjoining hectares, represents an striking example of Mediterranean dunal forest. Before all this study seek to draw up the balance sheet of the interventions conducted by the forest services from the beginning of the 20th century. The approach is based on the use of remote sensing data, compared with field information, for the build-up of a landscape units map. The Northern area of the Cap Bon, where the stamp of the coast is omnipresent, is characterized by a fast evolution of the natural habitat and by heavy landscapes changes. Many projects are planned and the society expectations are becoming insistent and often contradictory. Thus our thesis aim to analyse the changes assigned to the landscapes features. The comparison of georeferenced and multidate data allows to follow up the evolution of the rural landscape in the northern Cap Bon from 1900. It shows a sensitive change of the landscapes which illustrate itself by the progressive forestation of the large dunal sling of Dar Chichou. We endeavour to demonstrate the interest of such a methodology in reaching recommendation of new terms management able to fit the various functions of the forest habitat
Chaieb, Mohamed. "Influence des réserves hydriques du sol sur le comportement comparé de quelques espèces végétales de la zone aride tunisienne." Montpellier 2, 1989. http://www.theses.fr/1989MON20126.
Full textSelmi, Mohsen. "Différenciation des sols et fonctionnement des écosystèmes forestiers sur grès numidien de Kroumirie : (Tunisie)." Nancy 1, 1985. http://www.theses.fr/1985NAN10430.
Full textMonroy, Ata Arcadio. "Installation de plantes pérennes de la zone aride soumises à des contraintes hydriques contrôlées et à des coupes." Montpellier 2, 1989. http://www.theses.fr/1989MON20025.
Full textNiang-Freu, Fatou Kiné. "Tourisme et environnement littoral : les exemples de la Petite Côte et de la Grande Côte du Sénégal." Bordeaux 3, 2010. http://www.theses.fr/2010BOR30062.
Full textTourism is the second economic activity generator of revenue in Senegal. On the Senegalese coastline, particularly on the Little Coast and the Great Coast, it relies on reliable assets. However, it is also a factor of socio-cultural, economic and spatial transformation of the coastline. Through its developed sites, infrastructures and activities, touristic development creates a new environment that is often perceived as deterioration. This area is facing contamination and damage caused by sources which are not linked to tourism. This leads inevitably to negative impacts on the sustainability of investments in tourism. The thesis offers, firstly, a geographical analysis of disequilibrium between the Great Coast and the Little Coast of Senegal. It studies then the different strategies of management and development of parks, reserves, and cultural and historical heritage. Thirdly, it tries to suggest perspectives and solutions for a sustainable development and management of tourism in Senegal
Michel, Claude. "Exploitation des poissons en milieu lagunaire méditerranéen : dynamique du peuplement ichtyologique de la lagune de Tunis et des populations exploitées." Perpignan, 1986. http://www.theses.fr/1986PERP0017.
Full textHabib-Dhouibi, Mohamed. "Biologie et écologie d'Ectomyelois ceratoniae Zeller (Lepidoptera Pyralidae) dans deux biotopes différents au sud de la Tunisie et recherche de méthodes alternatives de lutte." Paris 6, 1989. http://www.theses.fr/1989PA066141.
Full textLespilette, Magali. "La phosphatase alcaline en milieu marin : ses caractéristiques, son évolution spatiotemporelle, son origine et sa régulation en relation avec le métabolisme des composés phosphorés dans la rade de Toulon." Toulon, 2009. http://tel.archives-ouvertes.fr/tel-00641975/fr/.
Full textOur work consisted of a monthly annual cycle of the evolution of the concentrations of the inorganic, hydrolysable organic phosphorus, oxidizable in the little bay and the large bay of Toulon (France). The activity of alkaline phosphatase (APA) responsible for conversions of the organic phosphorus in inorganic phosphorus was measured in parallel. The concentrations in inorganic phosphorus are always low (70-80 mM), in particular during summer. They fluctuate from April until September and are more stable during the rest of the year. The hydrolysable fraction represents in average 17-22 % of the total organic phosphorus which 4 % correspond to the hydrolysable fraction by the phosphatase. Those concentrations evolve in the same way as the inorganic forms. The dissolved APA represents 10 to 35 % on average of the total activity. It includes high and in low affinity components, the activity with low affinity being always higher than the strong affinity one. In both sites, the activities with weak affinity present maxima which coincide with phytoplanktonic abundances. The particulate activity is responsible of 60 % of the total activity. It also contains high and low affinity components. The activity with high affinity would be external and its optimal pH is close to sea water, while the activity with low affinity would be internal and its optimal pH is superior to 9. The high affinity of particulate activity is particularly high for the smallest size class (0,45-1 µm) while the low affinity one is higher for the largest size class (> 90µm). This intracellular activity is several hundred times higher for cirripeds larvae than to the other zooplanctonic forms. The high affinity APA is always low when SRP concentrations are high. On the other hand, it often increases when these concentrations decrease. When it is not the case, the concentrations in organic phosphorus hydrolysable were high. All these data allows to better understand the mode of regulation of the APA by the phosphorus compounds and to conclude that the measure of its strong affinity component can be considered as the best indicator of the phosphorus stress in Toulon bay
Grattepanche, Jean-David. "Trophodynamisme des protozoaires microzooplanctoniques en Manche orientale." Littoral, 2011. http://www.theses.fr/2011DUNK0300.
Full textThis PhD firstly aims to characterize the structure and variability of the heterotrophic protists community in the Eastern English Channel, in relation to the phytoplankton recurrent spring blooms and secondly to understand their trophic link with both phyto- and zooplankton. In situ survey was carried out from February 2007 to July 2009 and allowed to assess (1) the seasonal variability of heterotrophic protists related to the phytoplankton succession (bottom-up control) ; (2) the year to year variability in relation with Phaeocystis globosa bloom magnitude and duration ; (3) the importance of dinoflagellates as major consumers of phytoplankton, particularly of diatoms and P. Globosa colonies (<100 μm). This survey also suggested the top-down control on heterotrophic protists by copepods. Dilution ets carried out throughout the spring 2009 confirmed in situ observations. In fact, microzooplankton consumption often equalled or exceeded phytoplankton production. Results from size-fractionated dilution experiments revealed different size class of prey for ciliates (< 10 μm) and dinoflagellates (> 10 μm) suggesting the lack of trophic competition. The PhD then focused on the importance of heterotrophy in the Eastern English Channel via a dark microcosms experiment (19 days). This experiment confirmed that heterotrophic protists communities were efficient consumers of phytoplankton. Metazoans peaked one week delay after protists, suggesting time lag response to available trophic resource for these two groups. This experiment allowed to estimate the metazoan impact (particularly rotifers) on microplanktonic protozoans (predation/competition)
Vantrepotte, Vincent. "Caractérisation bio-optique des eaux côtières en Manche Orientale pour l'estimation de la production primaire et le suivi des poussées phytoplanctoniques : application à la télédétection satellitaire "couleur de l'eau" en milieu côtier." Littoral, 2003. http://www.theses.fr/2003DUNK0100.
Full textThe coastal ecosystems are among the most productive but also the most variable ones at both spatial and temporal scales. Remote sensing of "ocean colour" seems to be well adapted to study phytoplankton dynamics in such variable systems, due to its high spatial resolution and high temporal frequency. Remote sensing development in coastal waters (belonging to case 2 waters) requires simultaneously the characterization of : (i) the phytoplankton dynamics, (ii) the bio-optical properties of the optically active compartments of seawater (phytoplankton, yellow substances and non-phytoplankton particulate matter) and (iii) the variability of algal photosynthetic parameters. These points correspond to the objectives of our study, for which 5 mesoscale campaigns at sea were carried out in the eastern English Channel in 2000. At an ecological point of view, various ecosystems ("province") were discriminated on their hydro-biological characteristics. At a bio-optical point of view, the absorption spectra of yellow substances, phytoplankton and non-phytoplankton particulate matter present different dynamics (both at space and season scales), related to different environmental and/or biological factors. The variability of the algal photosynthetic parameters was studied on various spatial and temporal scales in order to define and adapted strategy for the mesoscale primary production modelling in the Eastern English Channel
Ben, Abdallah Manel. "Etude de la diversité microbienne (bactéries et archées) d'un environnement hypersalé tunisien, le Chott El Jerid : applications biotechnologiques." Thesis, Aix-Marseille, 2016. http://www.theses.fr/2016AIXM4757.
Full textThe present work concerns microbial biodiversity of prokaryotic communities, sulfate-reducing bacteria, and methanogens targeting the 16S rRNA gene and functional gene markers encoding the dissimilatory sulfite reductase β-subunit gene (dsrB) and alpha subunit of the methyl-coenzyme M reductase (mcrA), respectively from samples collected in the dry and wet seasons from Chott El Jerid. Phylogenetic analysis targeting the 16S rRNA gene showed that bacteria were grouped to Proteobacteria and Firmicutes detected at both seasons, whereas, Bacteroidetes, Actinobacteria and Betaproteobacteria were present only in the wet season. Deinococcus-Thermus group were observed in the dry season. Archaeal sequences were belonged to the phyla of Euryarchaeota in both seasons and Crenarchaeota was appeared in wet season. Sulfate-reducing bacteria, related to Deltaproteobacteria class were dominant mainly in wet season proved by two techniques DGGE and QPCR. From enrichment cultures, anaerobic fermentative bacteria were isolated in pure cultures, related to Halanaerobiaceae and Halobacteroidaceae families. Phylogenetic analysis, phenotypic and physiological characteristics showed a novel strain Sporohalobacter salinus related to Sporohalobacter lortetii, an unique species of genus Sporohalobacter described until now
Ellili, Ahlem. "Approche des mécanismes de tolérance d'Atriplex halimus subsp. halimus L. au sel et aux éléments traces métalliques et métalloïdes : perspectives pour sa gestion sur le territoire du Parc National des Calanques." Thesis, Aix-Marseille, 2017. http://www.theses.fr/2017AIXM0340.
Full textOn the PNCal, a multidisciplinary team has taken into account the pollution left by past industrial activities and works to reconcile the objectives of diffuse pollution management and biodiversity conservation. Atriplex halimus is a known invasive species in protected areas. It is necessary to provide criteria for deciding whether to maintain it for phytostabilisation or for its eradication on the maritime domain subject to seaspray and lead and arsenic pollution. The bibliographic analysis and examination of the aerial photographs of the site since 1925 does not indicate a recent implantation and invasion by A.halimus. The in situ study shows Atriplex halimus resistance to heavy metals and arsenic along a contamination gradient and in the saltspray area. This synchronic study was prolonged by the demonstration of a fluctuation of the health indicators of the aerial parts and the root symbionts associated with the seasonal physiological variations. We tested germination and growth of A. halimus ex situ and the soil-plant transfers on a wider range of soil pollution from the PNCal. The results: an inhibition of A.halimus growth in soil of PNCal related to soil pollution, salinity and oligotrophy. To the physiological tolerance to TMM mentioned in the bibliography, we added the determinant contribution of root symbiosis and the adsorption of TMM on the mineral phase. This study shows that the potential invasion of pollutant-tolerant plants can be easily tested by analyzing both the in situ study of spontaneous populations as well as the biotic and abiotic factors favoring their germination and growth in ex situ analyzes. This method provides decisive tools for managers of protected areas
Rossi, Nadège. "Ecologie des communautés planctoniques méditerranéennes et étude des métaux lourds (Cuivre, Plomb, Cadmium) dans différents compartiments de deux écosystèmes côtiers (Toulon, France)." Toulon, 2008. http://tel.archives-ouvertes.fr/tel-00439972/fr/.
Full textEcological studies of bacteria, phytoplankton and zooplankton are of major interest because these organisms constitute the food web basis. In coastal ecosystems, plankton communities are subjected to anthropogenic inputs which could influence their ecology. The framework of this study is plankton ecology and measurments of metal concentrations in different compartments of coastal ecosystems. An annual study (sampling twice a month) and a diel cycle were made in two neighbouring ecosystems differently affected by anthropogenic inputs, Little Bay and Large Bay of Toulon (France, north-west Mediterranean Sea), considering bacteria, phytoplankton and zooplankton communities. During the annual cycle, copper, lead and cadmium concentrations were measured in seawater, suspended particulate matter, bacteria, phytoplankton and zooplankton. Results showed that plankton ecology was principally influenced by meteorological conditions, both bays showing a different functioning because of their geomorphology. Plankton density was higher in Little Bay than in Large Bay, whereas diversity was higher in Large Bay than in Little Bay. Concerning metals, the in situ study showed metal concentrations higher in Little Bay than in Large Bay whatever the compartment studied. Some biological factors as density, taxonomic composition and the place where organisms live, showed an influence on the metal composition of plankton communities. Bacteria and phytoplankton showed great capacities to concentrate metals, in particular for copper and lead. In contrast, zooplankton constituted a break in the metal bioaccumulation along the food web. Finally, the important role of the suspended particulate matter as a metal trap was confirmed, showing the importance of working on pure plankton samples to have a good estimation of metal concentrations in the different plankton compartments
Reynaud, Christian. "Contribution à la formalisation et à la communication d'un concept d'écologie des milieux littoraux : les ecosystèmes paraliques - interprétation épistémologique et propositions didactiques." Montpellier 2, 1997. http://www.theses.fr/1997MON20039.
Full textLachenal, Anne-Marie. "Ecologie des ostracodes du domaine méditerranéen : application au golfe de Gabès (Tunisie orientale) : les variations du niveau marin depuis 30 000 ans." Lyon 1, 1988. http://www.theses.fr/1988LYO10037.
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