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Goulet, Guillaume, i Guillaume Goulet. "Système de contrôle automatisé de l'eau en culture de sphaigne". Master's thesis, Université Laval, 2019. http://hdl.handle.net/20.500.11794/37734.
Pełny tekst źródłaLa culture de sphaigne est la production durable de biomasse de sphaigne sur une base renouvelable et cyclique. Un système de contrôle de l’eau est nécessaire pour maintenir le niveau de la nappe phréatique à une valeur définie au cours de la saison de croissance dans un contexte de conditions climatiques variables. Peu d’information et de documentation sont disponibles concernant la conception et l’opération de systèmes de contrôle de l’eau dans les bassins de culture de sphaigne. Les objectifs de ce projet sont de définir, concevoir et réaliser le système de drainage et d’irrigation souterraine pour la culture de sphaigne et de développer un système de contrôle correspondant aux contraintes du site de Shippagan au Nouveau-Brunswick installé en 2014. La définition d’un système d’irrigation et de drainage adapté est basée sur les connaissances du drainage et de l’irrigation en agriculture et des besoins physiologiques de la sphaigne. Le développement des équipements a été réalisé en adaptant les concepts du système aux contraintes du site. L’analyse du système comprend les mesures à effectuer, les éléments à contrôler et les consignes d’opération. Les appareils de mesure du niveau de l’eau permettent d’évaluer et de transmettre au contrôle central les niveaux d’eau des fossés et de la nappe phréatique. Le contrôle central analyse les conditions et contrôle les pompes et les barrages à hauteur variable. L’énergie est fournie par un système de panneaux solaires et de batteries. Les barrages à hauteur variable permettent d’ajuster le niveau d’eau dans les fossés. Le système et les équipements développés répondent aux objectifs de conception. Des améliorations et une optimisation sont à faire. Le système permettra de continuer les travaux notamment au niveau de la modélisation de l’écoulement de l’eau et du contrôle prédictif.
Sphagnum farming is the cultivation of Sphagnum mosses to produce biomass of non-decomposed Sphagnum fibers on a cyclic and renewable basis. A water control system is required to maintain the water table level through the season, in the context of variable weather conditions. A drainage and sub-irrigation system has been designed and installed in 2014 on the Sphagnum farming site near Shippagan (N.B). The objectives of this project are to define the drainage and irrigation system for Sphagnum farming and develop an adapted system for the site. The design of the system is based on the Sphagnum requirements, agricultural knowledge of drainage and irrigation and respect of site constrains. Water level measurement equipment allows evaluation and transmission of the water table level and the water level in ditches to the central control. The central control analyzes the conditions and control the pumps and the variable level dams. The energy is supplied by a system of solar panels and batteries. The variable level dam adapts the water output level in the control structure. The developed system achieves the design objectives. Improvement and optimization are planned. The system will be the basis of future research, in particular about flow modeling and predictive control.
Sphagnum farming is the cultivation of Sphagnum mosses to produce biomass of non-decomposed Sphagnum fibers on a cyclic and renewable basis. A water control system is required to maintain the water table level through the season, in the context of variable weather conditions. A drainage and sub-irrigation system has been designed and installed in 2014 on the Sphagnum farming site near Shippagan (N.B). The objectives of this project are to define the drainage and irrigation system for Sphagnum farming and develop an adapted system for the site. The design of the system is based on the Sphagnum requirements, agricultural knowledge of drainage and irrigation and respect of site constrains. Water level measurement equipment allows evaluation and transmission of the water table level and the water level in ditches to the central control. The central control analyzes the conditions and control the pumps and the variable level dams. The energy is supplied by a system of solar panels and batteries. The variable level dam adapts the water output level in the control structure. The developed system achieves the design objectives. Improvement and optimization are planned. The system will be the basis of future research, in particular about flow modeling and predictive control.
Cazaurang, Simon. "Caractérisation des propriétés de transfert de la couverture végétale inférieure arctique : approche expérimentale et numérique couplée". Electronic Thesis or Diss., Toulouse, INPT, 2023. http://www.theses.fr/2023INPT0125.
Pełny tekst źródłaArctic environments are the regions that see the most significant climate warming of the Northern Hemisphere. These wetlands are widespread in Arctic ecosystems due to the large accumulation of organic matter (peat) produced by the organisms found there, Sphagnum mosses and lichens. The presence of large amounts of permanently frozen soil horizons (permafrost) makes these environments vulnerable. Numerous signals (increasing average annual temperatures, precipitation anomalies, changes in plant diversity) can already be observed. Climate projections for the year 2100 predict increases in temperature and precipitation in northernmost Arctic regions. These increases lead to the activation of climate feedback loops, which in return amplify climate change. The aim of this thesis is to study the low vegetation cover of Arctic wetlands (Sphagnum, lichens, peat) by considering them as a porous medium. A set of experimental and numerical techniques for studying porous media will be applied to samples from several sites: Khanymey (Siberia) as first place, but also Abisko (Sweden). Some samples from Clarens (France) are collected to serve as test samples. The samples are digitally reconstructed using X-ray tomography. The digital reconstruction is then used to study the morphological (§I), hydraulic (§II) and thermal (§III) properties of this biological porous medium. (§I) The morphological study shows a high porosity (sometimes more than 90%) for Sphagnum, lichen, and peat samples. High specific surface areas indicate a significant exchange and absorption potential for the study of element transfer. Representative Elementary Volumes (REV) may be defined for a majority of the samples. (§II) The simulation of a single-phase flow is used to compute the effective permeability of the studied samples. Samples with a REV are studied by direct numerical simulation at the REV scale. For samples without REV, a pore network is generated from the sample reconstruction. In both cases, the obtained values of the effective permeability tensor show a high hydraulic conductivity. The results are similar to other experimental tests reported in the literature and make it possible to overcome the problem of sample compressibility. (§III) The thermal properties are characterized using a coupled experimental and numerical approach. The experimental approach consists in studying the steady-state conductive heat transfer. The characterization of the effective thermal conductivity highlights the insulating property of the Arctic vegetation cover, with consistent values between each type of sample. The value of the intrinsic thermal conductivity of the plant material is calculated by inverse modeling of the experiments. Taken together, these transfer property studies provide a solid basis for generating an effective boundary condition for Arctic vegetation cover. However, further work is needed, in particular to quantify the influence of solar radiation flux on the energy balance of the Arctic vegetation cover. To this end, a preliminary work is presented that confirms the need for further information on the radiative transfer properties of this porous biological interface
Fabre, Marie-Chantal. "Aspects écologiques et cytologiques de la reproduction sexuée chez deux espèces de sphaignes (bryophyta) : Sphagnum palustre L. et Sphagnum flexuosum dozy et molk". Lille 1, 1987. http://www.theses.fr/1987LIL10132.
Pełny tekst źródłaPouliot, Kathy. "Les routes minérales en tourbières à sphaignes : restauration par enfouissement". Master's thesis, Université Laval, 2018. http://hdl.handle.net/20.500.11794/28316.
Pełny tekst źródłaThe electric power transmission lines network spans across the territory of the province of Québec on 34 000 kilometers and some of its sections inevitably go through peatlands. This restoration project has been conducted on two peatlands where access roads were constructed under power lines: at Sainte-Eulalie (Centre-du-Québec) and Chénéville (Outaouais). A mineral road in a peatland changes the nature of the substrate and can influence the water table level and the physicochemical characteristics of the water and peat. These changes can modify the composition and diversity of the vegetal communities. We examined if burying the mineral material within the bog is an effective method to restore the peatland conditions. The restoration by the “Burial Under Peat Layer Method” (BUPLM) consists in excavating and burying the mineral material beneath the underlying peat material. The method should allow to reach restorations goals by (1) confining the nutrients introduced with the mineral material, (2) by conserving a peaty surface elevation similar to the adjacent areas and (3) by re-establishing typical peatland vegetation. Whether it is 1 or 3 years post-restoration, the results of the physicochemical analyses of the water sampled at various depths and distances of the buried road showed similar nutriments concentrations to the means observed in the reference ecosystems. The soil elevation differences in the restored areas between readings are insignificant. Less than a growth season post-restoration, the Sphagnum mosses cover at Chénéville is 33 ± 9 %. At Sainte-Eulalie, 3 years post-restoration, the Sphagnum cover is lower (5 ± 3 %) because of the quality and quantity of the material available in the drained right-of-way. The results of this project show that the BUPLM complies with restoration objectives. Furthermore, it is economically profitable in comparison with the complete removal of the mineral material.
Picard, Hélène F. "Établissement d'espèces de sphaignes dans un contexte de production de biomasse". Thesis, Université Laval, 2010. http://www.theses.ulaval.ca/2010/27402/27402.pdf.
Pełny tekst źródłaLeroy, Fabien. "Effets des changements de végétation dans les tourbières à sphaignes sur le cycle du carbone". Thesis, Orléans, 2017. http://www.theses.fr/2017ORLE2029/document.
Pełny tekst źródłaPeatlands have stored a third of the soil organic Carbon (C) in only 3% of the land area. However, in response to global change, boreal and temperate peatlands may shift from Sphagnum to vascular plant-dominated peatlands that may alter their C-sink function. This thesis aims at providing a better understanding of the vascular plants interactions in a Sphagnum dominated peatland and their implications on the C cycle. This work mainly focus on the invasion of a graminoid plant, Molinia caerulea, through a mesocosm experiment. Results from experiments show that vascular plants are both able to promote the growth of Sphagnum mosses as well as the decomposition of their litter. Molinia caerulea occurrence appears to increase the C sink capacity of Sphagnum peat mesocosms passing of 30 to 220 gC stock m⁻² y⁻1. This capacity of Molinia caerulea to store C is probably due to it high roots productivity. However, it also seems to stimulate the decomposition of ‘old’ C, stored as peat, by stimulating microorganisms activity through roots exudates. These latter also promote the dissolved organic C consumption and CO₂ and CH₄ emissions observed with Molinia caerulea occurrence, as well as the temperature sensitivity of C exports by altering the microbial communities. Molinia caerulea impacts on microorganisms also affect N cycle conducting to a decrease of N₂O emissions in these ecosystems
D'Angelo, Benoît. "Variabialité spatio-temporelle des émissions de GES dans une tourbière à Sphaignes : effets sur le bilan carbone". Thesis, Orléans, 2015. http://www.theses.fr/2015ORLE2058/document.
Pełny tekst źródłaPeatlands cover only 2 to 3% of the land area but store between 10 and 25% of the soil carbon. The outcome of the anthropic and climatic pressure on these ecosystems is uncertain regarding their functions and storage. A better understanding of these ecosystems is needed to determine the factors and their interactions on greenhouse gas (GHG) emission. This work consist in monitoring GHG emissions and controlling factors in a Sphagnum peatland to estimate its carbon balance. Experimentation on mesocosms were carried out to explore the effect of hydrology on the fluxes and a monitoring on 4 sites was made to study the daily variability. Results show that La Guette peatland was a carbon source (-220 ± 33 gC m-2 an-1) in spite of the high water table level. The importance of the spatial variability measured in the site was also demonstrate. The hydrology effect was confirmed by the mesocosms experiments and high water table level shows that gas transport might have an effect. Finally the study of the daily variability show that the temperature sensitivity of the respiration might be different between day and night and that synchronizing soil temperatures and respiration can improve the respiration representation
Gilbert, Daniel. "Les Communautés microbiennes à la surface des tourbières à sphaignes : structure, fonctionnement et impact des apports de fertilisants". Clermont-Ferrand 2, 1998. http://www.theses.fr/1998CLF22084.
Pełny tekst źródłaAndersen, Roxane. "Évaluation du succès de la restauration écologique des tourbières à sphaignes : intégrations des critères physico-chimiques et microbiologiques au suivi à long terme". Doctoral thesis, Université Laval, 2008. http://hdl.handle.net/20.500.11794/20579.
Pełny tekst źródłaSt-Arnaud, Claudia. "Dynamique de la végétation d'un fen pauvre face à une simulation de réchauffement climatique : réponses potentielles des tourbières boréales à sphaignes". Thesis, Université Laval, 2007. http://www.theses.ulaval.ca/2007/24414/24414.pdf.
Pełny tekst źródłaGroeneveld, Elisabeth. "Le Polytrichum strictum comme stabilisateur de substrat et plante compagne pour les sphaignes dans la restauration des tourbières exploitées par aspirateur /". Online version, 2002. http://www.gret-perg.ulaval.ca/GROENEVELD%E%MSc.pdf.
Pełny tekst źródłaBugnon, Jean-Luc. "Perspectives de restauration des tourbières dans l'est du Québec, réintroduction des sphaignes sur des tourbières extrêmement sèches ayant été exploitées par aspiration et abandonnées et, effets de la présence des plantes vasculaires sur la croissance des sphaignes, sur d'anciens sites d'exploitation de la tourbe par la coupe de blocs". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp05/mq25519.pdf.
Pełny tekst źródłaAndersen, Roxane. "Évaluation du succès de la restauration écologique des tourbières à sphaignes: intégrations des critères physico-chimiques et microbiologiques au suivi à long terme". Thesis, Université Laval, 2009. http://www.theses.ulaval.ca/2009/25938/25938.pdf.
Pełny tekst źródłaFabre, Marie-Chantal. "Aspects écologiques et cytologiques de la reproduction sexuée chez deux espèces de sphaignes (bryophytes), Sphagnum palustre L. et Sphagnum flexuosum Dozy et Molk". Grenoble 2 : ANRT, 1987. http://catalogue.bnf.fr/ark:/12148/cb376049104.
Pełny tekst źródłaQi, Guifang. "Hydrophobie des matiéres organiques et ses conséquences sur l’hystérése et l’évolution de leurs propriétés hydriques : application aux supports de culture organiques horticoles". Angers, 2011. http://www.theses.fr/2011ANGE0074.
Pełny tekst źródłaThe precise knowledge over time of physical properties of a plant roots environment is important for the effective management of irrigation and fertilization. This work is devoted to the assessment of the variations in water retention, shrinkage/swelling and wettability of organic materials used as growing media during several drying and resetting cycles. An important effort is done to develop the methods used to measure simultaneously and continuously the changes in volumetric deformation of the massif (shrinkage/swelling) and its water retention properties. Three materials, sphagnum peat, black peat and coco coir were tested with suction up to -32 kPa. The curves obtained show an important evolution during the first drying and rewetting cycle, however the second and third cycle is repetitive and superimposed. The drying intensity has the impact on the irreversibility of water retention measured on peat, however it is not very perceptible with black peat and coco coir. All materials tested showed a double porosities character with a porosity inter-fiber or inter-grain emptied around -1 kPa and another porosity intra-grain with the air entry pressure variable depending on materials, -15 kPa for blond peat and -40 kPa for black peat. The water repellency of material during the drying was assessed with two methods: sessile drop and capillary rising methods. This methodological approach allows finding out their correspondence and difference. The variation of wettability depends mainly on the humidity of material. If the effect of “ink bottle” is probably crucial in explaining the hysteresis of water retention properties in the most wet states, using a bimodal model of van Genuchten introduced a contact angle in resetting has shown the water repellency can explain the hysteresis in the case of more intense drying suction
Jassey, Vincent. "Impact d’un réchauffement climatique sur le fonctionnement de la sphagnosphère : relations polyphenols-communautés microbiennes". Thesis, Besançon, 2011. http://www.theses.fr/2011BESA2011/document.
Pełny tekst źródłaCarbon stocks of Sphagnum-peatlands are likely to be altered by climate warming due to important changes in “Sphagnum-microorganisms” relationships which are responsible for carbon sequestration. The objectives of the thesis are (1) to identify the chemical interactions between Sphagnum-polyphenols and Sphagnum associated microbial communities and (2) to understand the impact of warming on these relationships.An experimental design using Open-Top-Chambers (OTC) was used to simulate an increase of air temperatures (+1°C) on a peatland situated in Jura Mountains (Frasne, 25). Temperature increase induced a modification of the microbial food web with an increase of the biomass of bacteria and a strong decrease of the biomass of top-predators (-70%), i.e. testate amoebae. Warming also induced a decrease of Sphagnum-polyphenols, diminishing their inhibitory effect on microbial communities. In parallel, an increase of phenoloxidase enzymatic activities was recorded in OTC. Climate warming thus modified polyphenol-phenoloxidase interplay, two crucial components of carbon cycle in peatlands. Warming effects on the different components – i.e. polyphenols, phenoloxidases, microbial food web – induced a modification of Sphagnum-microbial communities interplay, favoring carbon and nutrient recycling, which could alter peatland functioning in long-term
Jassey, Vincent. "Impact d'un réchauffement climatique sur le fonctionnement de la sphagnosphère : relations polyphenols-communautés microbiennes". Phd thesis, Université de Franche-Comté, 2011. http://tel.archives-ouvertes.fr/tel-00802903.
Pełny tekst źródłaPouliot, Rémy. "Initiation du patron de buttes et de dépressions dans les tourbières ombrotrophes boréales". Thesis, Université Laval, 2011. http://www.theses.ulaval.ca/2011/27853/27853.pdf.
Pełny tekst źródłaBlier-Langdeau, Ariane. "La réponse au feu des communautés végétales d'une tourbière ombrotrophe restaurée". Master's thesis, Université Laval, 2019. http://hdl.handle.net/20.500.11794/35465.
Pełny tekst źródłaOmbrotrophic peatlands (bogs) are known to be Carbone sink partially because of their resistance and resilience to fire. In a global climatic change context with politics aiming toward a reduction of atmospheric Carbone emission, a quick restoration of every degrade peatlands is desirable. The Canadian horticultural industry developed a promising peatland restoration technique. More than 100 sites were restored in Canada and despite many success indicators, we still hope that restored peatlands are resistantandresilient to fire. Indeed, few studies assess an ecosystem response to a disturbance happening after restorationandnone evaluates the response to fire of restored peatlands. At the end of summer 2014, a fire occurred in a Southern Quebec bog, partially burning a ten years old restored sectoranda natural one nearby providing the first opportunity to study the response to fire of a restored peatland. This research is divided in two objectives: 1) determine if the peat accumulation potentialandplant cover are the same between the burnedandunburned parts of the restored sector one growing season after fireand2) compare the mosses strata recovery between the naturalandthe restored sectors. The phytobiomass production rate was similar between the burnedandunburned parts of the restored sectorandthe burned parts plant cover growths significantly during the first growing season after fire, even reaching a similar level as the unburned parts for some areas. Sphagnumhummocks of the restored sectors showed a better resistanceandrecovery than the one in the natural sector. Thus, this study shows a tendency to resilience to fire of restored ombrotrophic peatlands.
Francez, André-Jean. "Production primaire et accumulation de matiere organique dans les tourbieres a sphaignes des monts du forez (puy-de-dome). Influence des activites humaines sur leur fonctionnement et leur evolution". Paris 6, 1990. http://www.theses.fr/1990PA066749.
Pełny tekst źródłaDelaine, Maxence. "La composition des thèques d'amibes xénosomiques : utilisation potentielle comme bio-indicateur des dépôts de particules d’origine atmosphérique". Thesis, Besançon, 2016. http://www.theses.fr/2016BESA2017/document.
Pełny tekst źródłaTheca-like amoebae, also called thecaamoebius, are unicellular microorganisms, which construct a rigid envelope called theca (Adl et al., 2012). These themes have very varied sizes, shapes and natures (Ogden & Hedley, 1980). Recent studies on the composition of the themes have led to the hypothesis that xenosomal amoebae (constituted by exogenous particles) can constitute relevant bio-indicators of the particulate diversity of the mineral, organic and biological environment in which they evolve . The main objective of the research carried out during this thesis is therefore to characterize the composition of the xenosomal amoebae and to evaluate their potential use as bioindicators of deposits of atmospheric particles. For this purpose, amoeba theae were analyzed in situ under natural conditions and after artificial deposits of allochtonous mineral particles. Several major conclusions can be drawn from this work: (1) The size of the mineral particles integrated in the xenosomal theca of Bullinularia indica Is similar to that of mineral particles transported into the atmosphere; (2) the mineral particles integrated into the thecs are stable silicates under the physico-chemical conditions prevailing in the peatlands, bryophytes and soils studied; (3) some minerals such as phlogopite, even when present in high concentrations, are never integrated by amoebae; (4) the combination of observations on the size, shape and nature of the particles used by xenosomic amoebae forms the basis for the use of tea amoeba for bioindication of recent or former atmospheric particulate diversity
Delarue, Frédéric. "Dynamique des matières organiques labiles et récalcitrantes dans la tourbière de Frasne (Jura) : impact des conditions hydriques et d'un réchauffement simulé in situ". Phd thesis, Université d'Orléans, 2010. http://tel.archives-ouvertes.fr/tel-00574496.
Pełny tekst źródła"Dynamique de la végétation d'un fen pauvre face à une simulation de réchauffement climatique : réponses potentielles des tourbières boréales à sphaignes". Thesis, Université Laval, 2007. http://www.theses.ulaval.ca/2007/24414/24414.pdf.
Pełny tekst źródła"Évaluation du succès de la restauration écologique des tourbières à sphaignes: intégrations des critères physico-chimiques et microbiologiques au suivi à long terme". Thesis, Université Laval, 2009. http://www.theses.ulaval.ca/2009/25938/25938.pdf.
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