Dissertations / Theses on the topic 'LAC'
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Ramirez-Sanchez, Hermes Ulises. "Caractérisation hydrologique et sédimentologique d'un lac tropical : le lac Chapala (Mexique)." Nice, 2001. http://www.theses.fr/2001NICE5648.
Full textThe lake Chapala is the most important lake of Mexico. The bottom is however poorly bumped ; the average depth oscillates of 4 in 7,7m. The catchment area is located in a vast graben of the orientation E-W, related to the volcanic transmexicain axis (MVB). After the study of 35 physico-chemical parameters of the lake water during the 90’s, the main factor of the short-term variation is the alternance seasons, dry and rainy. The most significant parameter in the evolution in the long-term is due to the overuse of Rio Lerma water. The comparative analyses of the 3 bathymetric maps suggests that the average rate accumulation of sediments was higher between 1981-1997 that during the time of 1929-1981. The sedimentological analyses show the dominant fraction is consisted by the silts, followed by the clayey fraction and very few sands. Mineralogically the composition is characterized by smectites, quarts, feldspars, calcite and hematite. Stronger concentration in Ni, pB, As and Cu is observed in the first 25 cm of the cores ; this suggests an anthropic influence, related to the industrial development. The analyses of diatoms and phytolithes allow highlighting the biogenic dissolution of silica and the magnetic analyses the presences of titanomagnetite of volcanic origin. The radiochemistry of the Cs, Pb and Pu isotopes allow to estimate rates of sedimentation (SR) vary between 1 and 7 mm/a. The Eastern part and especially the deltaic zones of the rivers Lerma and Pasion show higher values. The (SR) and the magnetic susceptibility allow locating the chronology of the volcanic events of the Volcano Colima. Finally the distribution of the (SR), the geological framework, and the flat morphology of the bottom of the lake indicate that probably the Chappala basin corresponds to area of rift in its final stage of evolution. A relative regional subsidence influences the (SR), higher on an axis apparently parallel with the rift direction
Tran, khac Viet. "Le rôle des facteurs environnementaux sur la concentration des métaux-tracesdans les lacs urbains -Lac de Pampulha, Lac de Créteil et 49 lacs péri-urbains d’Ile de France." Thesis, Paris Est, 2016. http://www.theses.fr/2016PESC1160/document.
Full textLakes have a particular influence on the water cycle in urban catchments. Thermal stratification and a longer water residence time in the lake boost the phytoplankton production. Most metals are naturally found in the environment in trace amounts. Trace metals are essential to growth and reproduction of organisms. However, some are also well known for their toxic effects on animals and humans. Total metal concentrations do not reflect their ecotoxicity that depends on their properties and speciation (particulate, dissolved: labile or bioavailable and inert fractions). Trace metals can be adsorbed to various components in aquatic systems including inorganic and organic ligands. The ability of metal binding to dissolved organic matter (DOM), in particular humic substances, has been largely studied. In urban lakes, the phytoplankton development can produce autochthonous DOM, non humic substances that can have the ability of metal binding.. But there are few studies about trace metal speciation in lake water column.The main objectives of this thesis are (1) to obtain a consistent database of trace metal concentrations in the water column of representative urban lakes; (2) to access their bioavailability through an adapted speciation technique; (3) to analyze the seasonal and spatial evolution of the metals and their speciation; (4) to study the potential impact of environmental variables, particularly of dissolved organic matter related to phytoplankton production on metal bioavailability and (5) to link the metal concentrations to the land use in the lake watershed.Our methodology is based on a dense field survey of the water bodies in addition to specific laboratory analysis. The research has been conducted on three study sites: Lake Créteil (France), Lake Pampulha (Brazil) and a panel of 49 peri-urban lakes (Ile de France). Lake Créteil is an urban lake impacted by anthropogenic pollution. It benefits of a large number of monitoring equipment, which allowed us to collect a part of the data set. In Lake Pampulha catchment, the anthropogenic pressure is high. Lake Pampulha has to face with many pollution point and non-point sources. The climate and limnological characteristics of the lakes are also very different. The panel of 49 lakes of Ile de France was sampled once during three successive summers (2011-2013); they provided us with a synoptic, representative data set of the regional metal contamination in a densely anthropized region.In order to explain the role of the environmental variables on the metal concentrations, we applied the Random Forest model on the Lake Pampulha dataset and on the 49 urban lake dataset with 2 specific objectives: (1) in Lake Pampulha, understanding the role of environmental variables on the trace metal labile concentration, considered as potentially bioavailable and (2) in the 49 lakes, understanding the relationship of the environmental variables, more particularly the watershed variables, on the dissolved metal concentrations. The analysis of the relationships between the trace metal speciation and the environmental variables provided the following key results of this thesis.In Lake Pampulha, around 80% of the variance of the labile cobalt is explained by some limnological variables: Chl a, O2, pH, and total phosphorus. For the other metals, the RF model did not succeed in explaining more than 50% of the relationships between the metals and the limnological variables.In the 49 urban lakes in Ile de France, the RF model gave a good result for Co (66% of explained variance) and very satisfying for Ni (86% of explained variance). For Ni, the best explanatory variables are landuse variables such as “activities” (facilities for water, sanitation and energy, logistical warehouses, shops, office…) and “landfill”. This result fits with Lake Creteil where dissolved Ni concentration is particularly high and where the “activities” and “landfill” landuse categories are the highest
Tassin, Bruno. "Contribution à la modélisation écologique du lac Léman : modèles physiques et biogéochimiques du lac." Phd thesis, Ecole Nationale des Ponts et Chaussées, 1986. http://tel.archives-ouvertes.fr/tel-00523061.
Full textBégin, Paschale Noël. "Limnologie d'un lac sentinelle dans le Haut-Arctique canadien : le lac Ward Hunt, Nunavut." Doctoral thesis, Université Laval, 2020. http://hdl.handle.net/20.500.11794/67774.
Full textArctic regions are experiencing increases in atmospheric temperature at rates that are two to three times faster than the global mean. A rapid contraction of the cryosphere has resulted from this warming, with a decrease in lake ice cover thickness, area and duration. Several effects of degradation of the ice cover on lakes have been documented, but there is a lack of information concerning polar lakes covered by multi-year ice. Ward Hunt Lake, Canada’s northernmost lake, was until recently characterized by a perennial ice cover that remained in place from at least 1953 onwards. This ice cover degraded rapidly in the past few years, making Ward Hunt Lake a far northern sentinel of Arctic climate change. The main objective of this thesis was to define the structure and function of this lake as a model to better understand the nature and implications of changes that polar lakes are undergoing now and in the future, and to address a series of questions and hypotheses about their horizontal and vertical gradients in the face of these changes. The influence of the ice cover on the physicochemical and biological structure of Ward Hunt Lake was evaluated with a spatiotemporal approach. A 2-year, high-frequency record was obtained with a mooring installed in the deepest point of Ward Hunt Lake. This allowed comparison of the seasonal dynamics of water temperature, chlorophyll fluorescence and dissolved oxygen concentrations between a year where the ice cover completely disappeared (2016) and a year where it remained (2017). The seasonal disappearance of the ice cover resulted in the loss of heat in the water column due to mixing throughout the water column. Water temperatures, which reached 6.5°C at the bottom before mixing, dropped to 1°C in the whole water column. Complete mixing also caused dissolved oxygen concentration in the water column to reach equilibrium with the atmosphere whereas it rose to 140% saturation under the ice cover. During open water conditions, incident radiation declined in the water column due to sediment resuspension and increased chlorophyll a fluorescence. The loss of ice cover may have stimulated primary productivity, with a higher and earlier chlorophyll a fluorescence peak in 2016 than in 2017. Sampling along an inshore-offshore gradient revealed two patterns of physical and biological variation. Both patterns included an abrupt shift at the ice cover margin, which acts as a demarcation between the littoral and offshore zones. The results underscored the ecological role of the narrow ice-free water area (moat) that forms around the ice cover of polar lakes each summer. Principal food sources for zooplankton were identified through the analysis of fatty acid composition of the different components of the food web. The pelagic zooplankton diet was mainly composed of seston whereas communities associated with mosses dominated their diet in the littoral zone. High populations of chironomids in the genus Metriocnemus occurred in the benthos. Analysis of the vertical structure of the Ward Hunt Lake water column in summer showed that the ice cover, by limiting direct exchange with the atmosphere, allowed the onset of inverse thermal stratification and the accumulation of heat despite blocking 40 to 60% of incident radiation by reflection and attenuation. Incident radiation reaching the lake floor allowed the development of a rich benthic community, with photosynthetic pigment stocks that were one to two orders of magnitude above those in the overlying water column. The stability of the water column also limited gas diffusion, resulting in oxygen supersaturation up to 180% of air equilibrium and the accumulation of carbon dioxide, nitrous oxide and methane. Optical analysis of the water column indicated the presence of weakly colored dissolved organic matter that influenced the underwater spectral radiation regime. This study provides an integrated view of perennially ice-covered lakes at a turning point as they undergo transition towards a seasonal ice-cover regime. It highlights the importance of ice cover as a driver of limnological variables in the water column by controlling the availability of solar radiation for photosynthesis, and by limiting wind-induced exchanges with the atmosphere, thereby favoring water column stability and strong inshore-offshore gradients in many ecosystem features.
Abraham, Roberto G. "Imaging of BL Lac objects." Thesis, University of Oxford, 1991. http://ora.ox.ac.uk/objects/uuid:8af2b188-06a4-4412-bd2a-6ee27b0bf781.
Full textBusquet, Thierry. "Lac caninum dans les hyperprolactinémies." Bordeaux 2, 1990. http://www.theses.fr/1990BOR25083.
Full textMaleval, Véronique. "Le Lac de Saint-Pardoux et l'évolution morphologique des lacs de barrage artificiel." Limoges, 2002. http://www.theses.fr/2002LIMO2007.
Full textTouchard, Laurent. "Le Baï͏̈kal et le Leman : géographie et histoire de la géographie de deux lacs." Paris 4, 1994. http://www.theses.fr/1994PA040126.
Full textThe aim of the thesis is to define the geographical personality of two lakes, a siberian lake of planetary importance, l ake baikal, and a lake of medium size of the piedmont of the alps, the lake of geneva, in order to effect a regionalizat ion of the two lakes, which is built on their geographical identity. The first part is the study of the limnological research about the twolakes, to determine the importance of the geography. Then, assets of the geography, cartography, globality, studies at different scales are used. Some forty analytic maps describe the lacustrine basins, waters and organisms, and, in a second time, two synthetic maps define the problematics of the lakes. Finally, the pkanetary-scale study of lake baikal and the lake of geneva includes the influence of the longitude, the plate tectonics, the biological evolution and endemism, the development of the human technologies, the drainage basin-scale study includes hydrological balances, sedimentary filling up, pollution and eutrophication, and the regional-scale study confirms the definition of the geographical personality of the lake
Patterson, Kathryn Grace. "Gene regulation in the lac operon." Thesis, Montana State University, 2009. http://etd.lib.montana.edu/etd/2009/patterson/PattersonK0809.pdf.
Full textLindner, Thomas 1978. "STACEE observations of BL Lac objects." Thesis, McGill University, 2006. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=102998.
Full textGroleau, Alexis. "Precipitation de calcite, sedimentation et cycle du phosphore dans un lac alpin. Etude du lac du bourget." Marne-la-vallée, ENPC, 2000. http://www.theses.fr/2000ENPC0012.
Full textGarnier, Josette. "Peuplement phytoplanctonique et bacteries heterotrophes d'un lac peu profond (lac de creteil, region parisienne) : production, fonctionnement, evolution." Paris 6, 1989. http://www.theses.fr/1989PA066196.
Full textSiriki, Driss. "Dynamique des populations et évolution métabolique du phytoplancton d'un lac eutrophe, Lac Aydat, Puy-de-Dôme, France /." 63-Aubière : Impr. U.E.R. Sci, 1985. http://catalogue.bnf.fr/ark:/12148/cb36110328s.
Full textTruong, Thi Lan Huong. "Développement d'un modèle conceptuel d'évaluation des projets écotouristiques : le cas du lac Tuyen Lam, Vietnam /." Trois-Rivières : Université du Québec à Trois-Rivières, 2005. http://www.uqtr.ca/biblio/notice/resume/24623035R.pdf.
Full textTruong, Thi Lan Huong. "Développement d'un modèle conceptuel d'évaluation des projets écotouristiques : le cas du lac Tuyen Lam, Vietnam." Thèse, Université du Québec à Trois-Rivières, 2005. http://depot-e.uqtr.ca/1305/1/000131043.pdf.
Full textStroffek, Stéphane. "Les transferts verticaux de matière et leur modification par les bactéries hétérotrophes fixées sur particules en sédimentation dans les eaux de surface de deux grands lacs alpins (lac Léman, lac du Bourget, France)." Lyon 1, 1990. http://www.theses.fr/1990LYO10221.
Full textTroin, Magali. "Réponse hydrologique du Lac Mar Chiquita (Argentine) aux changements climatiques : approche par modélisation couplée lac - bassin versant - climat." Aix-Marseille 3, 2010. http://www.theses.fr/2010AIX30035.
Full textThe subtropical latitudes of South America have been experiencing a major hydroclimatic change since the early 1970’s that has had a major societal impact affecting the local economy of one of the most densely populated regions. This change resulted in an abrupt increase in lake levels including Laguna Mar Chiquita, a lake which now covers 6000 km2, while the sedimentary records over the last millennium show a long drying trend. In order to gain a better understanding of the relation between lake level fluctuations and the climate variability in this region, this work aims to simulate the hydrological behaviour of Laguna Mar Chiquita and the relationship with its catchment. The implementation of the lake water balance indicates that lake fluctuations at the beginning of the 1970’s were in direct response to increased runoff in its northern sub-basin, suggesting a tropical climate influence. The coupling of the lake water balance with a hydrological watershed model has led to simulate lake level variations in relation with the climate of the northern sub-basin, highlighting the minor human impact in the recent hydroclimatic transition. For the first time, an integrated basin-lake model in link to global climate is presented combining the results of hydrological basin-lake modelling with the outputs of the climate LMDZ model through a statistical downscaling approach. This novel approach allows to explore the ability of global climate models to accurately represent the regional climate. In addition, it confirms the tropical influence on forcing of recent hydrological variabilities in this region of South America
Eon, Séverine. "Effets des radiations ionisantes sur un complexe ADN-protéine : le complexe entre l'opérateur LAC et le répresseur LAC." Orléans, 2001. http://www.theses.fr/2001ORLE2024.
Full textGalharret, Paul. "Le lac de Parentis-Biscarrosse (40) : étude hydrogéologique détaillée du régime du lac et de son bassin versant." Bordeaux 3, 1988. http://www.theses.fr/1988BOR30205.
Full textGalharet, Paul. "Le Lac de Parentis-Biscarosse (40) étude hydrogéologique détaillée du régime du lac et de son bassin versant /." Grenoble 2 : ANRT, 1988. http://catalogue.bnf.fr/ark:/12148/cb37613764g.
Full textOubraim, Saïd. "Dynamique des populations des cladoceres d'un lac eutrophe du massif central francais : "le lac d'aydat", biomasse et production secondaire." Clermont-Ferrand 2, 1987. http://www.theses.fr/1987CLF2S895.
Full textOubraim, Saïd. "Dynamique des populations des cladocères d'un lac eutrophe du Massif Central français, le lac d'Aydat biomasse et production secondaire /." Grenoble 2 : ANRT, 1987. http://catalogue.bnf.fr/ark:/12148/cb37608590g.
Full textPassinring, Kedeu. "Milieux naturels et paysages du bassin-versant des lacs de Léré : Département du lac Léré, Tchad." Aix-Marseille 1, 2006. http://www.theses.fr/2006AIX10013.
Full textBenech, Vincent, and Jacques Quensière. "Dynamique des peuplements ichtyologiques de la région du lac Tchad (1966-78) : influence de la sécheresse sahélienne." Lille 1, 1987. http://www.theses.fr/1987LIL10173.
Full textEl, Ghachtoul Youssef. "Dynamique des populations des copepodes d'un lac eutrophe du massif central francais : "le lac d'aydat" : vie active et vie latente." Clermont-Ferrand 2, 1987. http://www.theses.fr/1987CLF2S891.
Full textEl, Ghachtoul Youssef. "Dynamique des populations des copépodes d'un lac euthrope du Massif Central français, le lac d'Aydat vie active et vie latente /." Grenoble 2 : ANRT, 1987. http://catalogue.bnf.fr/ark:/12148/cb37605380w.
Full textGoni, Ibrahim Baba. "Réalimentation des eaux souterraines dans le secteur nigérian du bassin du lac Tchad : approche hydrogéochimique." Avignon, 2002. http://www.theses.fr/2002AVIG0031.
Full textSpott, Stefanie. "Die Dimerisierungsoberfläche des Lac-Repressors aus Escherichia coli." [S.l. : s.n.], 2002. http://deposit.ddb.de/cgi-bin/dokserv?idn=964717239.
Full textTremblay, Joseph. "Les pratiques d'employabilité au Saguenay-Lac-Saint-Jean." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp05/mq26840.pdf.
Full textLamontagne, Éric. "Étude de la fracturation au Lac-St-Jean /." Thèse, Chicoutimi : Université du Québec à Chicoutimi, 1993. http://theses.uqac.ca.
Full textBouquet, Christian. "Insulaires et riverains du lac Tchad : étude géographique /." Paris : l'Harmattan, 1991. http://catalogue.bnf.fr/ark:/12148/cb35506452q.
Full textCouradeau, Estelle. "Géomicrobiologie des microbialites du lac alcalin d'Alchichica (Mexique)." Phd thesis, Université Paris-Diderot - Paris VII, 2012. http://tel.archives-ouvertes.fr/tel-00934407.
Full textCouradeau, Estelle. "Géomicrobiologie des microbialites du lac Alcalin d'Alchichica (Mexique)." Phd thesis, Paris 7, 2012. http://www.theses.fr/2012PA077015.
Full textStromatolites are organosedimentary structures resulting from the activity of microbes. Fossil stromatolites are considered to be among the oldest traces of life on Earth. Although stromatolites dominate thé Precambrian geological record, the abiotic and biological processes leading to their formation are still poorly understood. The main objective of this work was to study the formation of modem microbialites in order to better constrain the interprétation of the fossil ones. We studied living microbialites from the alkaline Lake Alchichica in Mexico. The first part of this work has been devoted to the description of Alchichica microbialites including mineral phases and the associated microbial diversity. Results obtained allowed us to build a hypothetical model of metabolic-geochemical reactions leading to carbonate précipitation or dissolution in Alchichica microbialites. In a second chapter, we described the early stages of fossilization of cyanobacterial colonies belonging to the order Pleurocapsales within aragonite. This study opens new perspectives in the research of calcified cyanobacteria in ancient rocks. The third part reports the discovery of a cyanobacterium capable of performing controlled intracellular biomineralization. This strain, that we tentatively called Candidatus Gloeomargarita lithophora belongs to the basal cyanobacterial order of the Gloeobacterales and forms intracellular inclusions of amorphous Ba-Sr-Ca-Mg carbonates. The discovery of this new pattern of biomineralization in cyanobacteria opens new perspectives for the interprétation of ancient fossil record
Papon, Pierre. "Les plans d'eau superficiels : définition, fonctionnement, aménagements : étude du lac Balaton, du lac de Grand-Lieu et de l'étang de Cieux." Limoges, 2007. http://aurore.unilim.fr/theses/nxfile/default/eae82125-06b1-45bf-a9bb-06340fa362b0/blobholder:0/2007LIMO2006.pdf.
Full textDemory, François. "Paleomagnetic dating of climatic events in Late Quaternary sediments of Lake Baikal (Siberia)." Phd thesis, Universität Potsdam, 2004. http://opus.kobv.de/ubp/volltexte/2005/181/.
Full textLake Baikal provides an excellent climatic archive for Central Eurasia as global climatic variations are continuously depicted in its sediments. We performed continuous rock magnetic and paleomagnetic analyses on hemipelagic sequences retrieved from 4 underwater highs reaching back 300 ka. The rock magnetic study combined with TEM, XRD, XRF and geochemical analyses evidenced that a magnetite of detrital origin dominates the magnetic signal in glacial sediments whereas interglacial sediments are affected by early diagenesis. HIRM roughly quantifies the hematite and goethite contributions and remains the best proxy for estimating the detrital input in Lake Baikal. Relative paleointensity records of the earth′s magnetic field show a reproducible pattern, which allows for correlation with well-dated reference curves and thus provides an alternative age model for Lake Baikal sediments. Using the paleomagnetic age model we observed that cooling in the Lake Baikal region and cooling of the sea surface water in the North Atlantic, as recorded in planktonic foraminifera δ18 O, are coeval. On the other hand, benthic δ18 O curves record mainly the global ice volume change, which occurs later than the sea surface temperature change. This proves that a dating bias results from an age model based on the correlation of Lake Baikal sedimentary records with benthic δ18 O curves. The compilation of paleomagnetic curves provides a new relative paleointensity curve, “Baikal 200”. With a laser-assisted grain size analysis of the detrital input, three facies types, reflecting different sedimentary dynamics can be distinguished. (1) Glacial periods are characterised by a high clay content mostly due to wind activity and by occurrence of a coarse fraction (sand) transported over the ice by local winds. This fraction gives evidence for aridity in the hinterland. (2) At glacial/interglacial transitions, the quantity of silt increases as the moisture increases, reflecting increased sedimentary dynamics. Wind transport and snow trapping are the dominant process bringing silt to a hemipelagic site (3) During the climatic optimum of the Eemian, the silt size and quantity are minimal due to blanketing of the detrital sources by the vegetal cover.
Brisset, Elodie. "Sensibilité des milieux de montagne aux forçages climatiques et anthropiques depuis 14 000 ans dans les Alpes du Sud : Approche multidisciplinaire (sédimentologie, géochimie, palynologie) et multi-sites (lac Petit, lac de Vens et lac d’Allos)." Thesis, Aix-Marseille, 2014. http://www.theses.fr/2014AIXM3017.
Full textWithin the context of increasing demographic pressures and hazards related to climate change, the problems posed by landscape erosion have become particularly crucial. The current management of Mediterranean mountain environments, which are highly exposed to erosion hazards, needs to be supported by a thorough understanding of their susceptibility to these hazards and their long-term trajectories.A retrospective analysis of environmental trajectories has been conducted from the study of three lacustrine sedimentary archives in the Southern Alps (Lakes Petit, Vens and Allos). This multi-disciplinary study, based on sedimentology, geochemistry and palynology, has enabled characterization of the dynamics of erosion and changes in plant cover over the last 14,000 years.In Lakes Allos and Vens, the start of the Holocene is marked by the maturing of ecosystems, by chemical weathering of soils and by forest encroachment at higher altitudes. These environmental changes resulted in progressive ecosystem stabilization, followed by a bio-pedological optimum, and subsequently by more open landscapes, and then soil destabilization. These four successive phases have ben dated, respectively, at 12,000-8000 cal. BP, 8000-6000 cal. BP, 6000-1900 cal. BP, and 1900 cal. BP to Present. The last of these phases occurred earlier, at 4200 cal. BP, in Lake Petit.The triggering of soil erosion has systematically been hinged on periods of heavy precipitation affecting landscapes rendered vulnerable, by human societies, to the effects of such perturbations
Lejolivet, Catherine. "Contribution à l'étude du recrutement des poissons du réservoir de Pareloup (Aveyron) : élevage et étude de la phase planctonophage des brochetons (Esox lucius L.) : régime alimentaire, croissance, répartition spatio-temporelle de la communauté alevinique en zonelittorale." Toulouse, INPT, 1988. http://www.theses.fr/1988INPT012A.
Full textSauvé, Anthony. "De route et de rivière : dérives et déroutes au fil de l'eau; Rivière des Outaouais - Lac des Deux-Montagnes - Lac Saint-Louis." Thesis, Université d'Ottawa / University of Ottawa, 2016. http://hdl.handle.net/10393/35091.
Full textPetit, Muriel. "Dynamique de la communaute bacterioplanctonique d'un reservoir mesotrophe (lac de pareloup) : consequences de la vidange du lac - relations avec sa gestion hydraulique." Toulouse 3, 1997. http://www.theses.fr/1997TOU30183.
Full textL'Heureux, Houde François-Xavier. "Géomorphologie d'un lac de cratère d'impact météoritique profond ennoyé par un barrage hydro-électrique : le cas du lac Manicouagan, est du Québec." Master's thesis, Université Laval, 2017. http://hdl.handle.net/20.500.11794/28050.
Full textAnalysis of high resolution bathymetric data and acoustic sub-bottom profiles acquired during the summers of 2014 and 2016 in the Manicouagan reservoir allowed the identification of numerous forms and sedimentary processes on the slopes and lake floor of former Lake Manicouagan. The following geomorphological analysis aims at better understanding the basin’s sedimentary dynamics following the deglaciation. Reaching 322 m deep, Lake Manicouagan was the deepest know lake east of the Great Lakes, before the flooding of the Manicouagan reservoir, whose depth now reaches 452 m. Lake Manicouagan can be divided into three areas: The north area, with a flat lake floor and steep slopes eroded by channels. The central area, where the deepest basins can be found. The south area, with an hummocky lake floor and gentler slopes, eroded by large gully systems. Before the flooding, sedimentary supply to the lake floor was dominated by river sources, through their deltas, and by gravity currents, causing the erosion of channels and gullies. The flooding of the reservoir caused a rise in the importance of mass movements in sedimentary transport to the lake floor, while eliminating river imput transport to the deep basins. The river sediments are now mostly deposited on the shelves and shores of the Manicouagan reservoir.
Piette-Lauzière, Gabriel. "Évolution et diversité de deux formes de ciscos (nigripinnis et artedi) dans un drainage proglaciaire du lac Algonquin." Master's thesis, Université Laval, 2019. http://hdl.handle.net/20.500.11794/33492.
Full textLaurentian Great Lakes ciscoes (Coregonus artedi, sensu lato) diversity arose via repeated local adaptive divergence. Much of this diversity has vanished or is threatened. For instance, the nigripinnis form is now extirpated from the Great Lakes but remains in L. Nipigon. Ciscoes with some characteristics of nigripinnis have recently been discovered with sympatric artedi in lakes historically covered by the Fossmill outlet, a proglacial drainage of L. Algonquin. This raises the evolutionary hypothesis that artedi and nigripinnis could have colonized the area as distinct pre-existing lineages. Hence, putative nigripinnis may represent a relict embodiment of the historical diversity of ciscoes from the Great Lakes. The objective of this research was to characterize the phenotypic diversity and the evolution of newly observed putative nigripinnis and artedi. To do so, fish were grouped by habitat of capture (benthic and pelagic) and by gill raker counts and contrasted morphologically and genetically. Differentiation within and across lakes was often observed and paralleled that of artedi and nigripinnis in L. Nipigon. Gill rakers, caudal peduncle and body depth were the most important traits differentiating cisco forms. These traits are associated with varying foraging and locomotion strategies. Genetic analyses using 6676 single nucleotide polymorphism (SNPs) markers show that nigripinnis populations found in and nearby Algonquin Provincial Park origin from an Atlantic glacial lineage and repeated in situ divergence. Pairs of sympatric ciscoes were on a continuum of ecological, morphological and genetic differentiation across lakes. The divergence of nigripinnis could be associated to different resource exploitation, such as alternative zooplankton prey. This thesis confirms, by a comparative and integrative approach, the occurrence of a nigripinnis form with an independent evolutionary origin relatively to reference nigripinnis in L. Nipigon. The newly discovered nigripinnis populations could be source for the reestablishment of the functional diversity of the Great Lakes.
Morin, Isabelle. "Predicting the ice clearing capacity of Lac St-Pierre." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape4/PQDD_0021/MQ58488.pdf.
Full textHammar, Petter. "lac of Time : Transcription Factor Kinetics in Living Cells." Doctoral thesis, Uppsala universitet, Beräknings- och systembiologi, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-198814.
Full textRoy, Ann-Julie. "Reconstitution de l'état trophique du lac Nairne, Charlevoix, QC." Thesis, Université Laval, 2012. http://www.theses.ulaval.ca/2012/29000/29000.pdf.
Full textResidents and municipalities surrounding many southern Quebec lakes have expressed concerns since the early 2000s following massive cyanobacterial blooms that were followed by rapid deterioration of the lake’s water quality. As a consequence, several research programs have been initiated in order to provide those municipalities with an array of tools for a better management of these water bodies. In this context, the municipality of Saint-Aimé-des-Lacs, the Association pour la Protection de l’Environnement du Lac Nairne (APELN) and a partnership CIMA+/ULaval, have joined forces to conduct a paleolimnological research project at Lake Nairne. This concerted study aims at describing the past and recent evolution of Lake Nairne’s trophic state, and also to provide policy makers with tools for the development of management plans specifically designed for the lake’s watershed. As part of this concerted study, this master’s thesis describes Lake Nairne’s historical trophic state fluctuations. Using a paleolimnological approach, fossil diatoms, geochemical analysis and photosynthetic fossil pigments have shown progressive eutrophication of the lake basin since 780 years BC and rapid deterioration of the lake’s water quality following the beginning of agricultural and industrial activities in the lake’s watershed. However, improvements in water quality were also noted since the recent slowdown of industrial operations and vegetation recolonization since 1950. These results highlight the profound impact that human settlement and activities can have on the ecological stability of Lake Nairne, but also the capacity of such aquatic ecosystems to partly recover following substantial modification of the lake’s watersheds.
Lavoie, Caroline. "Géomorphologie et quaternaire du Lac Guillaume-Delisle (Nunavik), Canada." Thesis, Université Laval, 2006. http://www.theses.ulaval.ca/2006/24158/24158.pdf.
Full textCanosa, Celestino Miguel. "FRI-BL Lac unification using ROSAT X-ray observations." Thesis, University of Bristol, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.340153.
Full textLafforgue, Michel. "Modelisation du fonctionnement d'un ecosysteme lacustre : le lac d'aydat." Paris, ENMP, 1990. http://www.theses.fr/1990ENMP0313.
Full textHassen, Tarek Ben. "La grappe de l'aluminium au Saguenay-Lac-Saint-Jean." Thèse, Chicoutimi : Université du Québec à Chicoutimi, 2005. http://theses.uqac.ca.
Full textCaranhac, Fanny. "Modélisation de la dynamique de populations piscicoles exploitées intégrant la variabilité individuelle de croissance : application aux corégones (Coregonus lavaretus) du lac d'Annecy." Lyon 1, 1999. http://www.theses.fr/1999LYO10046.
Full textDelalande, Manuëlla. "HYDROLOGIE ET GEOCHIMIE ISOTOPIQUE DU LAC MASOKO ET DE LACS VOLCANIQUES DE LA PROVINCE ACTIVE DU RUNGWE (SUD-OUEST TANZANIE)." Phd thesis, Université Paris Sud - Paris XI, 2008. http://tel.archives-ouvertes.fr/tel-00403009.
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