Tesi sul tema "Réchauffement de la Terre – Éocène"
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Meunier, Mathias. "Biodiversity, biostratigraphy, disparity and macroecology of middle Eocene radiolarians (Rhizaria) : insights to their biotic response to the Middle Eocene Climatic Optimum (MECO)". Electronic Thesis or Diss., Université de Lille (2022-....), 2023. http://www.theses.fr/2023ULILR078.
The Middle Eocene Climatic Optimum (MECO) is a global warming event that occurred ca. 40 Ma and temporarily interrupted the long-term Eocene cooling trend. Although the MECO represents one of the larger climatic disruptions of the Paleogene, its impact on the biosphere is still poorly understood. Based on a wide range of quantitative methods, this thesis aims to study the radiolarian paleodiversity dynamics and morphological disparity through the MECO, in order to gain a deeper understanding of the biotic perturbations associated with this climatic event. The taxonomic understanding of middle Eocene radiolarian species was first clarified, by documenting at the species level two well-preserved radiolarian faunas recovered from two distinct geographic regions: the equatorial Atlantic (ODP site 1260) and the North Atlantic (ODP site 1051). A total of 276 species were identified, including 37 new to science. Taking advantage of the cyclostratigraphic framework developed at Site 1260, we refined the global tropical radiolarian biozonation. The absolute ages of 71 radiolarian bioevents were calibrated and, by comparison with the equatorial Pacific record, the synchroneity of primary bioevents was demonstrated. Once the taxonomic and biostratigraphic frameworks were clarified, the main aim of this thesis was to assess the radiolarian biotic sensitivity to climate change. Two categories of metrics were used to achieve this objective. On the one hand, we performed a whole assemblage quantitative analysis at ODP Site 1051. This detailed investigation of the radiolarian fauna did not reveal any prominent turnover during the MECO, but only a slight increase in radiolarian taxic richness due to the poleward migration of several tropical radiolarian species. On the other hand, we applied geometric morphometric approaches to quantify the morphological disparity of radiolarian shell through the MECO interval. This study was focused on a single species (Podocyrtis papalis) from Site 1260, and showed that fluctuations in morphological disparity coincide with the warmest interval of the MECO. This signal is interpreted as an indicator of biological stress induced by the warming event
Vautrin, Quentin. "Dynamique évolutive des faunes de mammifères du Sud-Ouest européen durant les réchauffements climatiques intenses de l’Eocène, entre 56 Ma et 45 Ma : le cas des Lophiodontidae". Thesis, Montpellier, 2019. http://www.theses.fr/2019MONTG057.
The early Eocene is marked by a succession of major global warming events that culminated in a period of climatic optimum (EECO) corresponding to the warmest period of the Cenozoic. Due to their short duration and high intensity, these hyperthermal events are often considered as the best analogues of current global warming, and are correlated with important diversification of mammals in the North American fossil record. In Europe, the early Eocene localities are less well known and it is difficult to trace the impact of these climatic events. Lophiodontidae are a family of perissodactyl mammals found in abundance in European Eocene localities, particularly in southern France, making them a model of choice for studying the impacts of hyperthermal events on the evolutionary history of European mammals. The first part of this work consists of an exhaustive study of the intraspecific variability of this family. More than thirty polymorphic dental characters have been identified, as well as the presence of marked sexual dimorphism. The genus Paralophiodon has been revised in light of this high variability and is considered invalid. In all, several hundred specimens from 22 localities in southern Europe were studied and 2 new species belonging to the genus Eolophiodon have been identified. The revision of the lophiodontids of the Occitanie region, placed in a biostratigraphic framework, allow us to rediscuss of the controversial age of the “grès d’Aigne”, and to propose a late Ypresian-early Lutetian age (MP10b-MP11) for this formation, thus filling the previous known gap in the European fossil record. The study of basal lophiodontids, coupled with the results of a new phylogenetic analysis, places the lophiodontids close to chalicothera within the suborder Ancylopoda, suggesting an Asian origin of the family and an arrival of lophiodontids in southern Europe soon after PETM. The study of unpublished material and phylogenetic analyses constrained by the new biostratigraphic data make it possible to distinguish three major phases in the evolutionary history of lophiodontidae that seem to be correlated with the major climate changes of the Eocene. Basal radiation of lophiodontidae is contemporary to the hyperthermal events of the Ypresian and is marked by the multiplication of small size forms and is restricted to the Mesogean Province. The second radiation of lophiodontidae appears contemporaneous with the EECO and its marked by the appearance of the genus Lophiodon and the replacement of small sub-cursorial forms by more massive taxa with sligthly more molarized premolars. This radiation marks the end of the endemism of lophidontidae that dispersed throughout all Western Europe. Lophiodontidae radiate one last time at Lutetien during the post-EECO cooling, during the "Intra Eocene Mammal Turnover I". This radiation sees the introduction of giant forms (one to two tons), graviportal and with molarized teeth, interpreted as a response to the relative opening of the environment during the post-EECO cooling leading to drastic changes in diets
Morin, Xavier. "Biogéographie des espèces d'arbres européens et nord-américains : déterminisme et évolution sous l'effet du changement climatique". Montpellier 2, 2006. http://www.theses.fr/2006MON20056.
Kernevez, Lydia. "Coopération environnementale et réchauffement global". Aix-Marseille 2, 2001. http://theses.univ-amu.fr.lama.univ-amu.fr/2001AIX24012.pdf.
Hurault, Benoît. "Comportement d'un pergélisol expérimental soumis à un réchauffement". Caen, 2011. http://www.theses.fr/2011CAEN2073.
The goal of this work was providing experimental data to better constrain the impact of global warming on permafrost. Methodology was based on physical modeling in a cold room. This allows identifying and defining the evolution processes of the experimental permafrost. Experimental permafrost was built-up based on available field data. The lithology of the material used was a mixture of fine sand and loam from the plain of Caen. Ice content is between 30 and 80 %. Models are not scaled and dimensional problems are not considered. Indeed, these experiments are a preliminary work. This study on the behaviour of an experimental warming permafrost allows a better understanding of (i) the changes in topography (thaw-settlement), (ii) the changes in the active layer, (iii) the thermal evolution of an experimental permafrost (freezing and thawing fronts monitoring) and (iv) the influence of different parameters (temperature, lithology, water-content, ice-content and ice-layer). This work has contributed to the development of new experimental techniques and it will enhance physical modeling databases on permafrost
Séjourné, Antoine. "Formation et évolution des structures périglaciaires en contexte de réchauffement climatique : comparaison Terre-Mars". Phd thesis, Université Paris Sud - Paris XI, 2011. http://tel.archives-ouvertes.fr/tel-00713531.
Abdoli, Asghar. "Rôle de la température dans la variabilité des traits d'histoire de vie : le cas du chabot (''Cottus gobio L.'') à l'échelle d'un réseau hydrographique (Bez, France)". Lyon 1, 2005. http://www.theses.fr/2005LYO10050.
Dezutter, Thibaud. "Réchauffement et «match-mismatch» entre le phytoplancton et le zooplancton dans la mer de Beaufort". Master's thesis, Université Laval, 2017. http://hdl.handle.net/20.500.11794/27589.
The unprecedented pace of warming of the Arctic Ocean affect a wide range of pelagic processes, from microalgal production to fish recruitment. Sediment traps deployed on oceanographic moorings at the Beaufort Sea shelf break were used to investigate the impact of changes in ice cover and water temperature on the phenology of ice algae, phytoplankton and herbivorous copepods from the Calanus genus. Water temperature, salinity, microalgal fluxes and composition, and zooplankton abundance and composition in the traps were monitored over 5 of the 6 annual cycles from September 2009 to September 2015 (no data in 2014). Satellite-derived sea ice concentration and modeled snow depth were also retrieved for the same period. For 4 of the 5 years monitored, the upward migration of Calanus hyperboreus along with nauplii abundance were synchronized with peaks in diatoms export while the migration of Calanus glacialis preceded the peak in export of the ice algae Nitzschia frigida by 6 to 8 weeks. A disruption of these patterns was observed in 2013 as a mismatch between primary and secondary producers was observed. First, unusual warm water temperatures and significant diatom flux from October to December 2012 led to a shoaling of C. hyperboreus females winter vertical distribution and, thus, important egg spawning above 100 m with numerous nauplii swimming into the trap in March-April. Second, the late snow and ice melt in summer 2013 delayed the ice algae export, resulting in a mismatch with C. glacialis and N. frigida. As ice algae and phytoplankton are essential food source for the reproduction and development of Calanus copepods, a mismatch likely had negative impact on their recruitment and on the subsequent transfer of energy to carnivorous copepods, fish, and seabirds. Such mismatch events between phytoplankton and zooplankton will potentially occur more often owing to the rapidly changing environmental conditions in the Arctic Ocean.
Buteau, Sylvie. "Étude de l'affaiblissement du comportement mécanique du pergélisol dû au réchauffement climatique". Doctoral thesis, Université Laval, 2002. http://hdl.handle.net/20.500.11794/35031.
Brient, Florent. "Etude de la réponse des nuages tropicaux à un réchauffement climatique simulée par les modèles de climat". Paris 6, 2012. http://www.theses.fr/2012PA066072.
Lété, Catherine. "Le polymorphisme des Ostracodes du bassin de Tremp (Ilerdien) et de l'Alabama (limite Eocène/Oligocène) : intérêt pour la reconstitution des paléoenvironnements, intérêt pour l'évolution (spéciation)". Bordeaux 1, 1987. http://www.theses.fr/1987BOR10562.
Hiriart, Yolande. "Équité et risque moral dans les politiques de lutte contre le réchauffement climatique". Paris 1, 2000. http://www.theses.fr/2000PA010005.
Cascella, Kévin. "Impact du réchauffement climatique sur le krill en milieux polaires : thermotolérance et réponse Hsp70". Thesis, Paris 6, 2014. http://www.theses.fr/2014PA066646/document.
Polar regions are the first to be impacted by global warming. The physiological impact appraisal of a temperature increase over local species is critical to foresee future evolutions of polar ecosystems. Physiological consequences of temperature rises can affect organisms both in their hardness and survival. Krill stands as a key component for polar ecosystems and therefore constitutes the core diet of local predators. In such context, a thermal tolerance comparative analysis of three distinct polar krill species has been carried out: two Antarctic species Euphausia superba and Euphausia crystallorophias, and one Arctic species,Thysanoessa inermis. The determination of thermal tolerance (CT50) was conducted on these three species. E. superba and T. inermis analysis showed similar thermal tolerances, while E.crystallorophias CT50 was slightly lower. Five isoforms of Hsp70 have been characterized foreach species. Their gene expression has been monitored through temperature increases of their environment. This biomarkers monitoring allowed an estimation of the critical temperature at which cellular damages appear. Kinetic expressions vary for each species: a strong response was observed in Hsp70 T. inermis, whereas response is much lower in E.crystallorophias. For similar temperatures, E .superba does not provide any Hsp70 response,despite its high thermal tolerance. The accumulation of heat shock experiments on this species, in intensity and duration, still did not provide any Hsp70 response, although it confirmed its highly noticeable heat tolerance for an Antarctic organism
Gillard, Morgane. "Réponses de plantes aquatiques invasives au réchauffement climatique". Thesis, Rennes 1, 2016. http://www.theses.fr/2016REN1B014/document.
Climatic models predict a rise of globale surface temperature about 1 to 4°C by 2100. Climate modifications generated by this warming might favor biological invasions. The general objectif of this thesis was to explore the impacts of climate warming and climate change on four macrophytes invasive in Europe. This work focused on germination, growth, physiology and distribution of these species, through experiments in controlled conditions, in experimental garden and by using species distribution models. We showed that i) higher temperatures favor moderately the germination capacity of Ludwigia hexapetala and Ludwigia peploides subsp. montevidensis, decrease the seedlings survivorship but improve their biomass production, ii) the effect of increased temperature on macrophytes depends on the season, iii) a 3°C warming can modify metabolism without generating changes on the growth, iv) the water primroses L. hexapetala is the only species that showed both better apical and lateral growth when facing a warming, v) models predict an increase of the distribution surface of Ludwigia spp., Myriophyllum aquaticum and E. densa in their invasive ranges, and a decrease of their distribution area in the other continents, including their native range. This thesis offer a better understanding of climate changes consequences on invasive macrophytes in order to anticipate their futur colonisation potential
Joulian, Catherine. "Aspects microbiologiques de l'émission de méthane par les sols de rizière". Aix-Marseille 1, 1998. http://www.theses.fr/1998AIX11019.
Daloz, Anne Sophie. "Importance du couplage océan-atmosphère sur la sensibilité au réchauffement climatique : impact sur les ouragans". Toulouse 3, 2011. http://thesesups.ups-tlse.fr/2641/.
Ocean-atmosphere interactions are essential for tropical cyclones. The ocean provides the energy required to sustain tropical cyclones. The simulation of interactions between the ocean and tropical cyclones is therefore crucial and is the focus of this thesis. The first section introduces the rotated-stretched and coupled version of the general circulation model ARPEGE-Climate, developed for this thesis. This rotated-stretched version achieves a spatial resolution between 60 and 100 km over the North Atlantic basin, resolution required to study tropical cyclones. The coupling of ARPEGE-Climate with oceanic general circulation model NEMO has also allowed taking in consideration ocean-atmosphere of tropical cyclones. Two types of simulations are performed, on the one hand coupled simulations and on the other hand simulations with prescribed sea surface temperatures from the coupled simulation. The second section focuses on the ability of general circulation models from the Intercomparison program, TC-MIP, to represent tropical cyclone activity and its precursors on the main development region of the North Atlantic Ocean. General circulation models have strong difficulties to represent tropical cyclone activity in this region, certainly related to their low spatial resolution, between 1° and 2. 5°. Although, the following precursors of tropical cyclone activity have been identified in this region : African easterly waves activity, Sahelian rainfall and especially those that occurs over the Fouta-Djallon, 11 ° N, sea surface temperatures and vertical wind shear horizontal on the main development region, tropospheric humidity over the African west coast. The third section of the thesis presents sensitivity tests that were performed on ARPEGE-Climate rotated-stretched and coupled with NEMO. These tests show the importance of the stretching pole position, the setting of the convection scheme parameters and the coupling frequency. In the fourth section, the configurations of ARPEGE-Climate coupled and forced are compared to assess the impact of ocean-atmosphere coupling on tropical cyclone activity in the North Atlantic basin. It appears that the coupling : modifies the geographical distribution of cyclone activity over the North Atlantic basin; modifies the activity of African easterly waves, which in turn affects cyclone activity over the main development region; changes the seasonal cycle of tropical cyclone activity over the main development region, and thus on the entire North Atlantic basin. This section also presents the similarities and differences of the sensitivity to global warming of forced and coupled simulations. Both configurations present : an overall decrease, although small, of tropical cyclone activity over the North Atlantic basin, a decrease in tropical cyclone activity in the southern Gulf of Mexico and Caribbean Sea, an increase of tropical cyclone activity in the Sargasso Sea, an intensification of tropical cyclones in terms of pressure and maximum wind, an increase in tropical cyclonic precipitations. The coupled and forced simulations also show some differences, especially regarding the evolution of the distribution of cyclone activity in the Sargasso Sea or the main development region. Another important difference is the nature of tropical cyclone in the future climate. The coupled configuration shows much greater differences on the changes of nature of tropical cyclones
Lejeusne, Christophe. "Habitat fragmenté et métapopulations en milieu marin : structures démographiques et génétiques d'invertébrés cavernicoles dans un contexte de réchauffement climatique". Aix-Marseille 2, 2005. http://theses.univ-amu.fr.lama.univ-amu.fr/2005AIX22096.pdf.
Habitat fragmentation and global warming are two major threats on biodiversity. How are the life-history traits of species dwelling in fragmented habitats able to maintain a balance between extinctions and colonisations? Dark marine caves are a particularly interesting habitat that might provide essential clues to answer such a question. Three species of cave-dwelling mysids (Crustacea) of the genus Hemimysis display different levels of habitat fragmentation in the north-western (NW) Mediterranean that was used to address this issue, in part with the help of molecular techniques. A survey of the populations of the two sympatric and syntopic species H. Speluncola and H. Margalefi could show that the latter had replaced the former in most of their distribution range. The reason was found to be a significant warming of the Mediterranean combined with an experimentally-demonstrated higher thermal tolerance in H. Margalefi. To better apprehend how such large-scale perturbations influence mysids, a biomarker of short-term effects (heat shock proteins, HSPs) was evaluated on a 4-yr time-series of H. Margalefi samples. A very fine and tight relationship was evidenced between the variability in HSP expression and seasonal temperature fluctuations. It represents an essential step towards a future use of HSPs as biomarkers of biological effects of global warming. Before conducting any phylogeographic or population genetic study, research on the population dynamics and reproduction biology of H. Lamornae mediterranea and H. Margalefi was completed. Reproduction was found to occur year round, with more intense periods of recruitment in the two species (respectively 3 and 4). The “thermophilic” character of H. Margalefi compared with the two other species was confirmed by some population parameters. A spectacular parasitic outbreak (Thalassomyces sp. , Ellobiopsidae) was recorded, that showed the role played by such parasites in population regulation, particularly through a decreased thermal resistance in H. Margalefi. A genetic study using the mitochondrial gene coding for subunit I of the Cytochrome Oxidase has shown a very strong genetic population structuring in the two cave-dwelling species H. Speluncola and H. Margalefi, but not in the sciaphilic H. Lamornae mediterranea, whose habitat is much less fragmented. H. Margalefi displays 8 distinct genetic groups in the NW Mediterranean, with much restricted gene flow oriented according to the general current circulation, following a stepping-stone with isolation by distance model. At smaller geographical scale, local hydrodynamic barriers unexpectedly affect gene flow and determine metapopulation sizes. On the contrary, H. Lamornae mediterranea only shows genetic structuring at a larger scale (the NW Mediterranean). Since the dispersal capabilities of these two brooding species are similar, such results clearly evidence how the level of habitat fragmentation influences genetic structures. In addition to detailing the relationship between habitat fragmentation and gene flow, the present work could show how species' resistance to stress interplays with habitat fragmentation in conditioning their survival abilities. In the current context of global warming, this type of study might prove a useful reference in the near future
Delanoë, Julien. "Modèle inverse et algorithmique pour exploiter la synergie radar-lidar dans les missions en tandem CLOUDSAT et Calipso ou dans la mission EARTH-CARE". Versailles-St Quentin en Yvelines, 2005. http://www.theses.fr/2005VERS0026.
Regarding climate change, direct and indirect effects of the non precipitating ice clouds are essential contributors to the earth radiation balance. The cloud properties are however still not well documented. Therefore, during this PhD we have developed radar and radar/lidar methods in order to document the microphysical and radiative properties of the non precipitating clouds. Using the new radar method (RadOn) we have developed and discussed a cloud climatology over three European sites in the framework of the European CloudNET project. We have also compared the climatology results to the representation of clouds in four European weather forecast models. In the framework of the preparation of the future spatial missions, CloudSat/Calipso and EarthCare
Dutertre, Mickaël. "Invasion des populations férales de l'huître creuse Crassostrea gigas : stratégies d'alimentation et de reproduction dans les habitats turbides". Nantes, 2009. https://archive.bu.univ-nantes.fr/pollux/show/show?id=a1eb1a5d-ae97-4563-9654-dc3c0e36e8d4.
The Pacific oyster Crassostrea gigas showed phenotypic variations of its gill and labial palp size in relation to the quantity and quality of the suspended particulate matter. When turbidity increased, the increase of the palp size and the reduction of the gill size allowed higher clearance rate and pre-ingestive selection efficiency of the particles. In natural conditions, reproductive strategies of farmed and feral oysters were chiefly dependant from water temperature, and seston quantity and quality. Gonad maturation, spawn and gamete atresia were associated with physiological thresholds of water temperature. Relatively similar reproductive efforts suggest that not only farmed oysters, but also feral oysters, contribute to the Crassostrea gigas proliferation. A significant increase of the feral oyster natural recruitment was related to the rise of summer water temperatures. This relationship supports the historical observations showing simultaneous coastal water warming and Crassostrea gigas invasion in northern temperate ecosystems. In 2008 and 2009, summer mortalities have decimated the Crassostrea gigas juveniles reared in the French coastal ecosystems but have not much affected the invasive feral oysters, which could therefore be used to boost oyster farming
Favillier, Adrien. "Impacts du changement climatique sur l’activité des avalanches dans les Alpes : apports de la dendrogéomorphologie pour la reconstitution spatiotemporelle de l’activité des avalanches dans un contexte de changements environnementaux dans les hautes vallées du Guil et du Rhône Disentangling the impacts of exogenous disturbances on forest stands to assess multi-centennial tree-ring reconstructions of avalanche activity in the upper Goms Valley (Canton of Valais, Switzerland) Spatio-temporal maps of past avalanche events derived from tree-ring analysis: a case study in the Zermatt valley (Valais, Switzerland) Tree-ring reconstruction of snow avalanche activity: Does avalanche path selection matter? Non-stationarities induced by land-cover changes in dendrogeomorphic reconstructions of snow avalanche activity: Insights from the Queyras massif (French Alps) Complex signals in regional tree-ring reconstructions of snow avalanches: lessons from the Goms valley (Swiss alps) Impacts des fluctuations climatiques sur l’activité des avalanches dans le Queyras". Thesis, Université Clermont Auvergne (2017-2020), 2019. http://theses.bu.uca.fr/nondiff/2019CLFAL024_FAVILLIER.pdf.
For the 20th century, high mountain areas, such as the Alps, have undergone a significant warming with temperature increase twice as much as the global average. Such warming strongly alters the cryosphere components. It induces, for example, a shift from solid to liquid precipitation, more frequent and more intense snowmelt phases or a strong decrease in the amount and duration of snow cover, especially at the elevation of the snowrain transition. In the future, climate models forecast that snow depth will be significantly reduced and that snow properties such as snow stability will be modified. These changes in snow cover characteristics and amounts are expected to induce significant changes in snow avalanches activity. At the same time, afforestation induced by the abandonment of agriculture and grazing, the democratization of winter recreation activities and the urban sprawl on the slopes have strongly modified the mountain landscapes since the mid-18th century as well as the exposition of individuals to snow avalanches. In this context, a precise documentation of past snow avalanche activity is crucial to decipher and to understand the impacts of the undergoing climate warming on the snow avalanche activity. To date, this documentation usually relies on historical chronicles or systematic observations. However, the firsts are often discontinuous and focused on catastrophic events. The seconds are limited to the second half of the 20th century thus precluding a comparison from climatically distinct period. On forested paths, the dendrogeomorphic approach is theoretically a reliable approach complement to historical archives and series of systematic observation to infer past snow avalanche activity. Yet, so far, the robustness of this approach has been poorly questioned and no regional chronology, crucial to disentangle potential interferences between snow avalanche activity, climate fluctuations and socio-economic changes, has been developed in the Alps. In this PhD thesis proposes new methodological frameworks to (1) detect avalanche events from tree-ring series, (2) remove non-stationarities related to the decreasing number of trees over time in the reconstruction and (3) aggregate locals reconstructions in regional chronologies. Based on these development, homogenized multicentennial regional chronologies developed (4) for 10 paths of the Goms Valley (Valais canton, Swiss Alps, 1880-2014) and (5) 11 paths from the Queyras Massif (French Alps, 1560-2016) are confronted to climatic fluctuations and land use changes. At Goms, the absence of clear climatic signal in the regional chronology evidence the interference with local nonstationarities and question the need for a sampling strategy at the regional scale to create a robust chronology. In the Queyras massif, the strong decrease of avalanche activity observed over the 20th century is attributed to global warming and to the afforestation process
Issa, Alaa m. issa. "Impact de la souche Psjn de Paraburkholderia phytofirmans sur la tomate en réponse à une température élevée". Thesis, Reims, 2019. http://www.theses.fr/2019REIMS027.
High temperatures resulting from climate change can significantly influence plant growth, development, and susceptibility to pathogens. In this situation, agriculture needs to better adapt to climate change.In this context, certain Plant Growth Promoting Rhizobacteria (PGPR) are able to protect plants against biotic and/or abiotic stresses. It has been shown in the laboratory that the PGPR bacterium, Paraburkholderia phytofirmans strain PsJN, gives the grapevine a better tolerance under low temperatures. This protection is partly attributed to the modulation of carbohydrate metabolism through the maintenance of photosynthesis and an increase of soluble sugars levels.During this work, the bacterium P. phytofirmans was used to induce heat tolerance to tomato plants to anticipate the global warming effects. The objectives of the work were to characterize, from an agronomic, biochemical, physiological and molecular point of view, the impact of the bacteria on the plant response under heat stress conditions.The results of this study demonstrated the importance of the use of P. phytofirmans strain PsJN as a biological agent especially with respect to global warming. These results will meet the expectations of tomato breeders who aim to develop increased productivity while respecting the environment and offering a better tolerance to biotic and abiotic stresses
Ladeira, Garbaccio Grace. "Les aspects juridiques et économiques liés aux changements climatiques : l' étude de cas de la sidérurgie". Limoges, 2009. http://www.theses.fr/2009LIMO1004.
Scotto, d'Apollonia Lionel. "Les controverses climatiques : une analyse socioépistémique". Thesis, Montpellier 3, 2014. http://www.theses.fr/2014MON30024/document.
This PhD dissertation sets out to analyze, in a socioepistemic way, the various controversies relating to global warming. This work is based on two objectives: (1) to develop and test a reflective analysis tool developed as an ongoing investigation in a single analytical framework articulating existing and occasionally controversial frameworks. (2) To analyze actors' strategies and arguments in the different areas of mediation concerning controversial climate system of knowledge, regarding the understanding to disentangle epistemological and axiological dimensions. This thesis is based on a bibliometric work to build a socio-historical reconstruction of the main controversial elements from the eighteenth century to the present time. Following this epistemological basis the analysis progresses in three steps. The first is an analysis based on a researcher's corpus (climatologists or otherwise) in various situation of communication, secondly completed by inquiry detailed survey with individual and collective interviews and finally a sociolinguistic analysis. Only then does it become possible to provide a radiography of global warming controversies restoring the part we can see, the In and the Off, to unravel the ontological, epistemological and axiological dimensions
Bercovici, Antoine. "Reconstitutions paléoenvironnementales du domaine ouest téthysien à la transition permien-trias : impacts relatifs du climat, de la ré-organisation de la biosphère continentale et des topographies sur la préservation des systèmes sédimentaires continentaux". Rennes 1, 2009. http://www.theses.fr/2009REN1S194.
The final buildup of Pangea at the end of the Palaeozoic led to the formation of massive landmass unrivaled in later times. On a climatic perspective, the end of the Carboniferous ice age opened into a period of progressive warming, creating vast arid regions on land. The lower Triassic is the culmination of this trend, and represents a period where land vegetation is scarce or non-existent. Two causes can be inferred: the extreme aridification of climate or the slow recovery of terrestrial floras after the permo-triassic crisis (disappearance of 85% of species). During the lower Permian, continental sedimentation was limited in a series of isolated endoreic basins, in between differences in preservation and floral assemblages can be observed. In all sedimentary basins of the north-western tethyan domain, with the exception of the germanic basin, the Permian/Triassic transition is characterized by a lack of sedimentary deposition of variable time. All these observations imply the existence of a still active Variscan range, modifying the palaeoclimatic conditions and controlling sedimentation in the end-Permian sedimentary basins of western Europe. However, the general evolution of Permian floras is still linked at the first order to the global warming event, leading to profound modifications on terrestrial biotas long before the permian/Triassic biotic crisis
Doxa, Aggeliki. "Complex population dynamics in a changing environment : the impact of density dependence and environmental factors on the vital rates and dynamics of two long-lived bird species". Paris, Muséum national d'histoire naturelle, 2009. http://www.theses.fr/2009MNHN0001.
One of the challenges of modern population ecology is to provide the effective tools for population dynamics predictions in a rapidly changing environment. Reliable estimations of the effects of environmental variation on species dynamics require to integrate the effects of populations intrinsic parameters (e. G. , density) as well as external environmental factors. Importantly, these interacting effects are influenced by current and past conditions of the system, at both local and global scales. The present thesis aims to illustrate some of the aspects that need to be considered when assessing the impact of density and climatic factors on life history traits and on population dynamics, by using the example of two long-lived bird species, the Dalmatian pelican (Pelecanus crispus) and the Great white pelican (Pelecanus onocrotalus). The analyses showed that patterns of density-dependence can significantly interact with severe environmental stochasticity, producing unpredicted effects on population extinction risk. Large-scale climatic factors together with population density may similarly influence the survivorship of different population segments, resulting to spatial and temporal synchronisation between and within populations. Finally, interactions between until now cooperative species that are differently affected by climatic change may be a critical aspect for their future capacity to effectively respond to changing conditions
Legendre, Serge. "Les communautés de mammifères du paléogène (éocène supérieur et oligocène) d'Europe occidentale : structures, milieux et évolution". Montpellier 2, 1988. http://www.theses.fr/1988MON20036.
Crombet, Yann. "Impact du réchauffement climatique et de l'acidification des océans sur les diatomées". Thesis, Aix-Marseille, 2013. http://www.theses.fr/2013AIXM4030.
Specifically orientated on the diatoms' phytoplanktonic group, this work tryed to understand the impact of warming and ocean acidification on diatoms and aimed at understand the taxon's response to the ongoing climate change. Amospheric pCO2 increase since the first industrial revolution lead to the augmentation of dissoveld inorganic carbon (DIC) concentration in the surface ocean, and thus to the ocean acidification, accompanied by an ocean surface warming leading finally to the extension of oligotrophic areas well stratified and nutrient depleted. Different in situ and lab techniques were used in order to better understand the diatom role in oligotrophic system and their response to warming and acidification in an oligotrophic chemostat, limited by phosphate
Ben, Rais Lasram Frida. "Diversité ichtyologique en Méditerranée : patrons, modélisation et projections dans un contexte de réchauffement global". Montpellier 2, 2009. http://www.theses.fr/2009MON20004.
Due to its semi-enclosed shape, to its high species richness and high endemism levels and to its invasiveness, the Mediterranean Sea is one of the most particular and critical ecosystems of the world. The Mediterranean has been intensively studied since the Antiquity, yet foundations underlying fish diversity patterns have been overlooked. In this study, as a first step, we studied fish diversity patterns in the Mediterranean and their determinants. Towards this objective, we built the first comprehensive database on the spatial distributions of the 619 Mediterranean fish species. We then carried out spatial analyses in order to assess the relative contribution of historical and geometric contingencies as well as environmental influences in shaping fish biodiversity patterns. In a second step, we analyzed the correlates of dispersal success of exotic species and we assessed the spatial congruence with the endemic ichtyofauna within a global warming context. Finally, we modeled the present climatic envelopes of the most vulnerable Mediterranean fish species, i. E. The endemic species. We used those models to project expected spatial distributions of endemic species according to a global warming scenario in order to identify winner versus loser species as well as areas where a strong species turnover would occur. We showed that geometric constraints, primary production and temperature have an influence on species diversity patterns. It also appeared that the climate and the year of introduction into the Mediterranean are key determinants of the dispersal success of Lessepsian species. Within a global warming context, our results revealed an increasing spatial congruence between endemic and exotic fish faunas and for the latter, deep modifications in their assemblages expected in 2041-2060 and 2070-2099. In sum our results suggest that endemic species undergo a biotic pressure via exotic species and an abiotic pressure via global warming. The additional and potentially the synergetic effect of those pressures is likely to increase endemic species vulnerability
Lauffenburger, Mireille. "Estimation du réchauffement climatique dans le sud-est de la France (à l'est du Rhône), à la fin du XXIème siècle (2071-2100)". Aix-Marseille 1, 2007. http://www.theses.fr/2007AIX10022.
Dang, Christian K. "Rôle fonctionnel de la biodiversité : hyphomycètes aquatiques et décomposition des litières dans les cours d'eau". Toulouse 3, 2006. http://www.theses.fr/2006TOU30200.
Bodin, Xavier. "Géodynamique du pergélisol de montagne : fonctionnement, distribution et évolution récente : l'exemple du massif du Combeynot (Hautes Alpes)". Paris 7, 2007. http://www.theses.fr/2007PA070035.
This study intends to understand the state and the functioning of the mountain permafrost in a crystalline and poorly glacierised massif (Combeynot Massif, Hautes Alpes, France) on one hand, and on the other hand to express its distribution and evolution at variable spatic and temporal scales. First, the monitoring devices, helped by three very different years in nivo-meteorological terms, have revealed some of the main features of the thermal processes at the Laurichard rockglacier surface. The spatialisation of the winter surface temperatures clearly shows the influence of the very warm 2003 summer followed by the snowy 2003-2004 winter, that both contributed to prevent the cooling of the ground. This relation with the seasonal snow history, especially in early winter, is also demonstrated by the analysis of the annual velocity of the rockglacier and of the climatic data during the last two decades. At the scale of the whole massif, the relation climate/permafrost has been modelled by a statistico-empirical relationship which reproduœs the influence of the topoclimatic conditions on the permafrost. Four case studies have nevertheless revealed that the geodynamical context and its evolution during the Quaternary are essential in understanding the state and the distribution of the permafrost at slope and watershed scales. Finally, the recent climate warming seems to have induced a temporary speed-up of the creeping velocity of the permafrost, which subsequently arises the question of the stability of degrading slopes
Calmels, Fabrice. "Genèse et structure du pergélisol : étude de formes périglaciaires de soulèvement au gel au Nunavik (Québec nordique), Canada". Caen, 2005. http://www.theses.fr/2005CAEN2063.
Helioui, Khalil. "Le choix des permis d'émission négociables dans la lutte contre le réchauffement planétaire : enseignements d'une analyse économique". Paris, EHESS, 2004. http://www.theses.fr/2004EHES0027.
The Kyoto Protocol adopted Emission Trading (ET) to control greenhouse house gas emissions. However, the viability of this system is under question. This thesis assesses it potential sources of efficiency losses : transaction costs, market power, and dynamic distortions. We show that the last phenomenon is the most worrying. To what extent a control on domestic policies might reduce these distortions? The idea proves impracticable: too many uncertainties surrond the relevant control parameters. Comparing quantity against price instruments, we propose a hybrid scheme, ET combined with an international carbon tax, as a compromise between economic efficiency and political acceptability. While ET remains relevant to initiate and enlarge a climate coalition, the introduction of an international carbon tax could, in a second stage, strengthen coordination performances: since it diminishes permit value, it would reduce dynamic distortions and facilitate an agreement on the allocation of future emission rights. Such a hybrid instrument may ensure the long term viability of ET; and contribute to a renewed climate action
Fuentes, Espinoza Alejandro. "Vin, réchauffement climatique et stratégies des entreprises : comment anticiper la réaction des consommateurs ?" Thesis, Bordeaux, 2016. http://www.theses.fr/2016BORD0150/document.
It’s commonly accepted that global warming will have important consequences formany vineyards throughout the world, with impacts on wine production, on grape quality andtherefore on wines quality. In Bordeaux and other regions, warming is partly the cause of achange in the chemical composition of the grapes harvested under conditions of excessivematurity. The wines resulting from their vinification are richer in alcohol, less acidic andmarked by aromatic characteristics reminiscent wines produced in warmer and dryer latitudes.In this context, global warming will involve important economic stakes in wine consumption,and it may be useful to know the capacity of consumers to accept these wines durably. Theobjective of this thesis work is both forward-looking in relation to global warming and itsconsequences on wines quality and at the same time on the sustainable match between supplyand demand.The analysis methodology is an experimental market coupled with a sensory analysis.Experiences with consumers showed the influence of the characteristics of global warmingwines on consumer’s preferences and the wines valorisation on the market. Finally, the resultsshow that consumers have differentiated valorizations for oenological processes aimed atcorrecting the negative effects of global warming
Govetto, Benjamin. "Impact du réchauffement climatique : conséquence d'une élévation de la température sur la gamétogénèse analysée chez Rosa". Thesis, Aix-Marseille, 2017. http://www.theses.fr/2017AIXM0188.
Polyploidization, e.g. the increase in the number of chromosomes sets in an organism, is a phenomenon that would have contributed to the advent of major evolutionary steps such as the emergence of the seed and the flower in plants.Polyploidization can be induced by environmental clues, more particularly by thermal variations resulting in the production of 2n. It has been shown, in roses, that the application of high temperatures (from 30°C) during male gametogenesis leads to a high production of diplogametes as well as a high repression of the expression of the gene RhPS1, orthologue of the A. Thaliana AtPS1 gene. AtPS1 is involved in the formation of diplogametes, whose loss of function mutant has a strong production of male diplogametes, resulting from meiotic abnormalities. This work aims at characterizing or providing elements allowing for better comprehension of the RhPS1 function, by (i) the analysis of the phenotypes of rose lines showing a decrease of these transcripts, (ii) by looking for these potential protein interactors and (iii) investigating genes potentially regulated by RhPS1. The results of this work show that RhPS1 has a similar function to AtPS1 in A. thaliana. Thus, when this gene has a lower expression, meiotic abnormalities are only observed during the metaphase II stages or during the transition of Anaphase I / Metaphase II. Even though no protein interactant could be found, some genes potentially regulated by RhPS1 have been identified
Fouché, Julien. "Effets du réchauffement climatique sur le fonctionnement biogéochimique de deux cryosols arctiques dans la région de Salluit, Nunavik, Canada". Doctoral thesis, Université Laval, 2014. http://hdl.handle.net/20.500.11794/25418.
L’augmentation de la décomposition de la matière organique des cryosols arctiques sous l’effet du réchauffement et de la dégradation du pergélisol contribuerait à une rétroaction positive sur les changements climatiques. Nous étudions les interactions entre le régime thermique, le comportement hydrique et le fonctionnement biogéochimique de deux cryosols, l’un développé dans une tourbière (cryosol histique : H) et l’autre dans des argiles marines postglaciaires (cryosol turbique : T), en conditions naturelles et réchauffées expérimentalement. Les profils ont été instrumentés à Salluit (Nunavik, Canada ; 62°14’N, 75°38’W) et les mesures ont été faites pendant les étés 2010 et 2011. Du fait des propriétés isolantes de la tourbe, la couche active du site H est moins épaisse que celle du site T. Le réchauffement augmente la respiration de l’écosystème (ER) de manière plus intense pour H que pour T, bien que ER pour H soit plus faible. La sensibilité thermique de ER (Q10) est supérieure pour T que pour H et diminue avec le réchauffement pour les deux sols. L’étude montre que les cycles journaliers de ER forment des hystérésis en fonction de la température de surface du sol. L’explication de la variance de ER est améliorée lorsqu’on prend en compte la température minimale de la journée et la profondeur du front de dégel pour H. Pour T, l’ajout de la vitesse du vent et la radiation solaire améliore l’explication de la variance de ER. Nous montrons trois dynamiques spécifiques aux écosystèmes nordiques : 1) ER est dépendante des propriétés du sol et de la composition de la solution du sol ; 2) des variables thermo-indépendantes affectent significativement ER et 3) Q10 évolue au cours de la journée, la respiration basale varie d’une année sur l’autre. La décomposition de la matière organique serait la principale source de CO2 pour H alors que les processus végétaux contrôleraient ER pour T. L’approfondissement du front de dégel contrôle les concentrations des solutés dans la solution des deux cryosols. Nos résultats contribuent à la compréhension et à l’extrapolation des mesures ponctuelles dans les écosystèmes de toundra, pouvant amener à l’amélioration de la modélisation du cycle du carbone dans les cryosols. Mots clés : cryosol histique et turbique, modélisation thermique, teneur en eau volumique, toundra, réchauffement expérimental, respiration de l’écosystème, solution du sol, pergélisol arctique, décomposition de la matière organique, respiration dérivée de la végétation.
Increased organic mater decomposition rate in Arctic Cryosols due to warming and to permafrost thawing can lead to the release of greenhouse gases, thus potentially creating a positive feedback on climate change. We aim to assess the interactions between the thermal regime, the hydric behaviour and the biogeochemical functioning of two different permafrostaffected soils (i.e. Cryosols), one being developed in frozen peat (Histic Cryosol: H), the other being developed in postglacial marine clays (Turbic Cryosol: T), both in natural conditions and under an experimental warming. Profiles were instrumented in Salluit (Nunavik, Canada; 62°14’N, 75°38’W) and monitored during summers 2010 and 2011. Both thermal monitoring and modeling results stressed differences between sites due to the insulating properties of dried peat in summer the active layer at the H site is thinner than at the T site. The induced warming increased CO2 fluxes in both soils; this impact was however more striking at H even if ecosystem respiration (ER) was lower than at T. Temperature sensitivity of ER (Q10), which decreased with warming, was higher at T than at H. We highlighted that diurnal ER cycles showed hysteretic loops as a function of soil surface temperatures. Linear models performed to explain ER variance were improved when we added daily minimum temperature and thaw front depth at H. In contrast at T, adding wind speed and solar radiation in models improved the ER variance explanation. We showed three specific CO2 flux dynamics related to northern ecosystems: 1) the large difference of ER depending on soil properties and soil solution composition; 2) environmental variables strongly alter CO2 fluxes and 3) the diurnal Q10 variations and the inter annual variability of basal respiration. Our results support the assumption that organic matter decomposition might be the major source of CO2 at H while plant-derived processes dominated ER at T. Finally, the thaw front depth controlled solute concentrations in the soil solution at H and T. Our results contribute to understand and extrapolate the numerous punctual measurements of CO2 fluxes from tundra ecosystems, improving carbon cycle modeling in Cryosols. Keywords: Histic and Turbic Cryosol, Thermal modeling, Volumetric water content, Tundra, Experimental warming, Ecosystem respiration, Soil solution, Arctic permafrost, Organic matter decomposition, Plant-derived respiration.
Razakamanarivo, Ramarson Herintsitohaina. "Potentialités de stockage du carbone dans le système plante-sol des plantations d'eucalyptus des hautes terres malgaches". Montpellier SupAgro, 2009. http://www.theses.fr/2009NSAM0028.
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.
Carbon 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
Iltis, Corentin. "Effets du réchauffement climatique sur la performance d’un ravageur des cultures et impact sur les relations tritrophiques". Thesis, Bourgogne Franche-Comté, 2019. http://www.theses.fr/2019UBFCK051.
Global warming poses a major challenge to living organisms, particularly for ectothermic animals like insects, whose physiology and behaviour are closely related with direct thermal surroundings. This thesis aims at experimentally investigating the impacts of climate change on the overall performance of a major grapevine pest, the European grapevine moth (Lobesia botrana), and the associated consequences for interactions involving this phytophagous insect and adjacent trophic levels, more specifically natural enemies (parasitoids). The experiments conducted focus on three facets of climate change: an increase in mean temperature, an alteration of daily thermal range, and the occurrence of heat waves as extreme thermal events.Results highlight an impact of temperatures on both life-history traits related with larval performance (defensive abilities of caterpillars) and adult reproductive success, with demonstrated repercussions for the interaction between this pest and an oophagous parasitoid. Furthermore, they reveal an important variability of thermal responses occurring among traits and even facets of climate change, thereby suggesting complex consequences of this phenomenon in terms of pest population dynamics. Hence, predicting a species response to climate change requires adopting an integrative perspective of the biology of the focal species while considering the complexity of changes occurring in insect direct thermal environment
Calvès, Isabelle. "Effets du réchauffement climatique, de l’hypoxie et de la contamination chimique sur les réponses évolutives de populations de flet (Platichthys flesus)". Brest, 2011. http://www.theses.fr/2011BRES2067.
In this study, we explored molecular, physiological and genetic responses of flounder (Platichthys flesus) populations located in five estuaries showing contrasted environments: in Portugal (the Mondego: the southern limit of the flounder distribution area), in France (the eutrophicated Vilaine, the heavily polluted Seine, the pristine Canche) and in England (the polluted Tamar). Firstly, the genetic structure of these populations was analysed considered microsatellites and underlined the maintenance of the genetic diversity in the peripheral population of the Mondego; furthermore, significant differentiations by pair of populations underlined the particular genetic status of this Portuguese population. Secondly, the pattern of genetic variability observed for a candidate gene involved in the energetic metabolism, the AMP-desaminase, suggested that cocktails of pollutants act as selective agents directly or indirectly on this locus, in chronically contaminated systems (Seine & Tamar). The phenotypic responses of the flounder were measured in three estuaries (the Seine, the Vilaine and the Mondego). Investigations on gene expression showed CO II mRNA levels obviously reduced in the Mondego vs the other estuaries, and more generally that the flounder may minimize mitochondrial densities and maximize their ATP synthesis capacities in the most southern part of its distribution area. Estimations of average daily growth rate reading otoliths of juveniles suggested the existence of a latitudinal pattern, i. E. A growth rate increasing towards the North of Europe. Furthermore, hypoxia challenge tests were conducted in the laboratory and showed a differential pattern of resistance to hypoxia in the three populations; the population of the Mondego displaying probably a reduced capacity of resilience when faced to an additional stress as hypoxia. This study suggests several hypothesis on the functioning of natural populations in “extreme environments” that interact with them in novel or intense ways
Tabet, Jean-François. "Le contencieux de la responsabilité civile des risques naturels et technologiques". Montpellier 1, 2008. http://www.theses.fr/2008MON10034.
Dubois, Catherine, e Catherine Dubois. "Adapter les quartiers et les bâtiments au réchauffement climatique : une feuille de route pour accompagner les architectes et les désigners urbains québécois". Doctoral thesis, Université Laval, 2014. http://hdl.handle.net/20.500.11794/25461.
Thèse en cotutelle: doctorat sur mesure en ambiance physiques architecturales et urbaines, Université Laval, Québec; Institut National des Sciences Appliquées (INSA), Toulouse, France
L’augmentation des températures estivales induites par le dérèglement climatique est préoccupante pour les villes des latitudes tempérées froides parce qu’elle exacerbe le phénomène d’îlot de chaleur urbain (ICU) et réduit le confort thermique à l’intérieur des bâtiments. Le territoire de la Communauté métropolitaine de Québec (CMQ) sert de cas d’étude. Les architectes et les designers urbains, s’ils acquièrent les connaissances et les compétences adéquates, peuvent être aussi des acteurs clés de l’adaptation au changement climatique. Deux ateliers de travail collaboratifs réunissant architectes, ingénieurs et designers urbains ont fait état de lacunes à ce sujet. La création d’un outil d’aide à la conception (AAC) spécialisé sur la question de l’adaptation du cadre bâti à la chaleur a été envisagée pour résoudre ce problème. Une recension et une catégorisation d’outils d’AAC ont été conduites pour identifier les qualités susceptibles d’atteindre ce but. Pour le confirmer, sept des outils d’AAC recensés ont été testés par 14 étudiants inscrits à un atelier d’architecture de deuxième cycle de l’Université Laval. Les résultats de l’enquête qui comprend une analyse des présentations finales des projets, un questionnaire électronique et deux groupes de discussion conduits avec les étudiants de l’atelier ont mis en évidence la diversité et la pluralité des besoins des utilisateurs d’outils d’AAC. Pour ces raisons, nous proposons une « feuille de route » (FDR) de l’adaptation au changement climatique pour orienter les praticiens à travers la création d’un projet adapté à la hausse des températures estivales. Celle-ci comprend deux volets : le premier cherche à améliorer la compréhension des praticiens des principaux enjeux de l’adaptation au changement climatique par une organisation graphique et systémique des savoirs. Le deuxième cible et hiérarchise des outils d’AAC qui leur permettent d’acquérir ou de parfaire leurs connaissances de manière autonome. Huit entretiens individuels avec des praticiens de la région de Québec ont été conduits pour vérifier l’atteinte de ces objectifs. Les principaux résultats confirment : i) la capacité de la FDR d’améliorer la compréhension des praticiens, ii) l’intérêt des praticiens pour la formule d’autoapprentissage proposée et iii) la présence des qualités recherchées par les utilisateurs d’outil d’AAC dans la FDR.
L’augmentation des températures estivales induites par le dérèglement climatique est préoccupante pour les villes des latitudes tempérées froides parce qu’elle exacerbe le phénomène d’îlot de chaleur urbain (ICU) et réduit le confort thermique à l’intérieur des bâtiments. Le territoire de la Communauté métropolitaine de Québec (CMQ) sert de cas d’étude. Les architectes et les designers urbains, s’ils acquièrent les connaissances et les compétences adéquates, peuvent être aussi des acteurs clés de l’adaptation au changement climatique. Deux ateliers de travail collaboratifs réunissant architectes, ingénieurs et designers urbains ont fait état de lacunes à ce sujet. La création d’un outil d’aide à la conception (AAC) spécialisé sur la question de l’adaptation du cadre bâti à la chaleur a été envisagée pour résoudre ce problème. Une recension et une catégorisation d’outils d’AAC ont été conduites pour identifier les qualités susceptibles d’atteindre ce but. Pour le confirmer, sept des outils d’AAC recensés ont été testés par 14 étudiants inscrits à un atelier d’architecture de deuxième cycle de l’Université Laval. Les résultats de l’enquête qui comprend une analyse des présentations finales des projets, un questionnaire électronique et deux groupes de discussion conduits avec les étudiants de l’atelier ont mis en évidence la diversité et la pluralité des besoins des utilisateurs d’outils d’AAC. Pour ces raisons, nous proposons une « feuille de route » (FDR) de l’adaptation au changement climatique pour orienter les praticiens à travers la création d’un projet adapté à la hausse des températures estivales. Celle-ci comprend deux volets : le premier cherche à améliorer la compréhension des praticiens des principaux enjeux de l’adaptation au changement climatique par une organisation graphique et systémique des savoirs. Le deuxième cible et hiérarchise des outils d’AAC qui leur permettent d’acquérir ou de parfaire leurs connaissances de manière autonome. Huit entretiens individuels avec des praticiens de la région de Québec ont été conduits pour vérifier l’atteinte de ces objectifs. Les principaux résultats confirment : i) la capacité de la FDR d’améliorer la compréhension des praticiens, ii) l’intérêt des praticiens pour la formule d’autoapprentissage proposée et iii) la présence des qualités recherchées par les utilisateurs d’outil d’AAC dans la FDR.
For mid-latitude cities, higher summer temperatures due to climate change are a cause for concern because they aggravate the urban heat island phenomenon and reduce thermal comfort inside buildings. The territory of the Quebec Metropolitan Community (CMQ) is used as a case study. By acquiring the appropriate knowledge and skills, architects and urban designers can become key actors in adaptation to climate change. Two workshops bringing together architects and urban designers provided evidence of deficiencies in this area. We hypothesized that a design support tool (DST) focused on the issue of adaptation of mid-latitude cities to rising summer temperatures could help improve knowledge and skills of professionals in the field. We conducted a review and classification of DSTs, which highlight the tools’ features that are likely to reach this goal. To verify this, seven DSTs were selected and tested by fourteen students enrolled in a graduate-level architecture design studio. The results from this test, including an analysis of the final projects, a web-based questionnaire and two focus groups, highlighted the diversity and plurality of DSTs user needs. For these reasons, we propose a "roadmap" (RM) of the climate change adaptation to guide practitioners through the design of a project adapted to higher summer temperatures. It includes two parts: the first aims to improve the practitioners understanding of the key issues of climate change adaptation through a graphical and systemic organization of knowledge. The second seeks to target and prioritize DSTs that enable practitioners to acquire or enhance their knowledge on a self-learning basis. Eight individual interviews with professionals working within the CMQ territory were conducted to verify the RM goals achievement. The main results confirm : i) the RM ability to improve the practitioners understanding, ii) the interest of practitioners for the RM formula based on self-learning and iii) the presence of the qualities sought by the DSTs users within the RM.
For mid-latitude cities, higher summer temperatures due to climate change are a cause for concern because they aggravate the urban heat island phenomenon and reduce thermal comfort inside buildings. The territory of the Quebec Metropolitan Community (CMQ) is used as a case study. By acquiring the appropriate knowledge and skills, architects and urban designers can become key actors in adaptation to climate change. Two workshops bringing together architects and urban designers provided evidence of deficiencies in this area. We hypothesized that a design support tool (DST) focused on the issue of adaptation of mid-latitude cities to rising summer temperatures could help improve knowledge and skills of professionals in the field. We conducted a review and classification of DSTs, which highlight the tools’ features that are likely to reach this goal. To verify this, seven DSTs were selected and tested by fourteen students enrolled in a graduate-level architecture design studio. The results from this test, including an analysis of the final projects, a web-based questionnaire and two focus groups, highlighted the diversity and plurality of DSTs user needs. For these reasons, we propose a "roadmap" (RM) of the climate change adaptation to guide practitioners through the design of a project adapted to higher summer temperatures. It includes two parts: the first aims to improve the practitioners understanding of the key issues of climate change adaptation through a graphical and systemic organization of knowledge. The second seeks to target and prioritize DSTs that enable practitioners to acquire or enhance their knowledge on a self-learning basis. Eight individual interviews with professionals working within the CMQ territory were conducted to verify the RM goals achievement. The main results confirm : i) the RM ability to improve the practitioners understanding, ii) the interest of practitioners for the RM formula based on self-learning and iii) the presence of the qualities sought by the DSTs users within the RM.
Lenoir, Sylvain. "Impact du réchauffement climatique sur la distribution spatiale des ressources halieutiques le long du littoral français : observations et scénarios". Thesis, Lille 1, 2011. http://www.theses.fr/2011LIL10047/document.
This aims to study the impact of climate warming on the spatial distribution of fish in the North Atlantic, using the new habitat model called the Non-Parametric Probabilistic Ecological Niche Model (NPPEN). The model NPPEN is nonparametric and requires only presence data. It is based on concept of the ecological niche sensu Hutchinson. The model NPPEN tests the Mahalanobis generalised distance by permutations to produce and map the probability of species occurrence. The model is therefore well suited to study expected changes in the biogeography of marine species at macro-scale. Applying this new model on more than fifty marine species in the North Atlantic, has highlighted the impact of global warming on the biogeography of species, structure and trophodynamic of the marine ecosystem. Disruption, already observed in spatial distribution and abundance (probability of occurrence) of fish species such as Atlantic cod and lesser sandeel were found again. The majority of species will move northward to stay in an environment consistent with their ecological niche. The intensity and rapidity of the biogeographic movements expected, as the balance of gains or losses in the spatial range differ among fish; governed by the ability of species movement, their range of environmental tolerance (niche breadth) and the intensity of global warming
Hamon, Mathieu. "Caractérisation des effets du réchauffement climatique sur l'océan superficiel au cours des 50 dernières années". Thesis, Brest, 2012. http://www.theses.fr/2012BRES0095/document.
To identify and characterize the effects of global warming is one of the major scientific challenges of this new century. The rise of sea level, the hydrological changes are some consequences of this phenomenon which will influence all forms of life on Earth. Due to its high thermal capacity, it is estimated that 84% of the energy developed by global warming is stored in the first layers of the ocean. However, it is rather difficult to assess its overall impact over the last 50 years because the ocean is not warming uniformly and the inhomogeneous sampling (spatial and temporal) of oceanographic observations, instrumental errors (XBT) and biases related to the estimation process of global indicators can affect our assessment of the evolution of ocean parameters. To overcome these difficulties of in situ measurements analysis, we propose here an empirical correction of XBT data based on the analysis of collocated profiles, characterized by a parabolic function of the immersion of the probe and a thermal offset. From the corrected database, we present a new method for creating large-scale gridded fields based on the reconstruction of the natural modes of variability (DINEOF). Finally, we present the main results from these reconstructions in terms of global trends and variability of heat content and freshwater content. This work contributes to better document the oceanic variability in the 0-700m layer
Amiraux, Rémi. "Ice biota degradation in the Arctic environment : impact of bacterial stress state on this material's preservation and burial". Electronic Thesis or Diss., Aix-Marseille, 2017. http://www.theses.fr/2017AIXM0189.
With a rise in Arctic temperatures almost twice as large as the global average in recent decades, it is at high latitude that the effects of global warming are the most evident. Thus, some scientists have already predicted the complete disappearance of sea ice for 2050. Due to the future disappearance of ice algae and the increase of permafrost thawing, a reassessment of their respective contributions to CO2 storage was required. We have shown that unlike permafrost, ice algae are highly preserved in sediments (allowing CO2 storage) due to the inability of their bacteria to remineralize them. The combined effect of increasing discharge of permafrost by Arctic rivers and decreasing storage of ice algae due to the disappearance of sea ice should thus contribute to increase the global warming
Denis, Benjamin. "La politique internationale du climat: analyse du processus de construction du cadre international de lutte contre le réchauffement global". Doctoral thesis, Universite Libre de Bruxelles, 2006. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/210881.
Doctorat en sciences politiques
info:eu-repo/semantics/nonPublished
GOUGET, HERVE. "Etude de l'ozone troposphérique et de ses précurseurs à partir de l'interprétation des campagnes aéroportées STRATOZ III et TROPOZ II". Toulouse 3, 1996. http://www.theses.fr/1996TOU30249.
Drouet, Kévin. "Impact de la température sur la biogéographie et la phénologie des dinoflagellés benthiques toxiques du genre Ostreopsis en Méditerranée et en Atlantique". Electronic Thesis or Diss., Sorbonne université, 2020. http://www.theses.fr/2020SORUS379.
Harmful algal blooms (HABs) associated with the toxic benthic dinoflagellate Ostreopsis spp. are increasing around the world and responsible for sanitary, economic and ecological issues. The increasing number of reports of this dinoflagellate in recent decades suggests that climate change, and more particularly ocean warming, may be partly responsible for its expansion, especially in temperate zones. However, this link between warming waters and the development of Ostreopsis spp. blooms is difficult to prove and data concerning distribution areas or cellular responses to thermal variations are still lacking. This PhD thesis work provides new elements to answer this issue by addressing three main themes: 1) the phenology of blooms, 2) the distribution of species along a latitudinal gradient and 3) physiological adaptations to a temperature gradient. These questions were addressed by keeping the effect of temperature on the ecology of Ostreopsis spp. as the main thread and link between the three questions asked. This work was carried out using a multidisciplinary approach including statistical analyzes of datasets, genetic approaches based on environmental DNA, as well as ecophysiology and ecotoxicology approaches. The data used were acquired both from samples collected in the field and from experiments in a controlled environment in the laboratory. To meet the first objective, we analyzed the time series resulting from the ongoing monitoring of O. cf. ovata summer blooms in Monaco (NW Mediterranean Sea) set up since 2007 in order to determine the relationship between blooms phenology and environmental parameters. Although no environmental factor measured was able to fully explain the phenology of blooms, a strong positive correlation was found between positive sea surface temperature anomalies during spring and the timing of blooms, suggesting that the warmer the spring, the earlier the blooms of O. cf. ovata in Monaco. The second question of the thesis was addressed by analyzing new samples collected as part of a sampling campaign conducted along the coast of the Bay of Biscay in August-September 2018. This campaign aimed to establish the current distribution of Ostreopsis spp. in this area exhibiting a strong South-North thermal gradient, in order to initiate the analysis of a possible future expansion due to ocean warming. The processed results combined a classic benthic sampling approach, the use of artificial substrates for the collection of environmental DNA analyzed through molecular tools (rt-qPCR) as well as a Lagrangian modeling approach aiming at establishing the connectivity between sampling areas. We showed that only O. cf. siamensis was present in the Bay and that it could be found in certain areas up until the entrance to the English Channel, although blooms of O. cf. siamensis were only observed in the southeastern part of the Bay. This study allowed us to identify sentinel zones along the Bay of Biscay where new long-term monitoring could be set up in order to observe the potential expansion of O. cf. siamensis towards the North of the bay. Finally, the response of Ostreopsis spp. in relation with varying temperatures was studied in terms of growth capacity, physiological adaptations and toxicity in a thermal acclimation experiment. Different monoclonal strains were compared, including strains of O. cf. siamensis isolated in the Bay of Biscay during our 2018 campaign, as well as strains of O. cf. ovata from the northwestern Mediterranean Sea, correspongind to the two areas studied this thesis. The first results of this experiment indicate that the strains of O. cf. siamensis are able to acclimate and grow at temperatures between 16 ° C and 25 ° C, with an optimum growth temperature estimated around 22 ° C. In addition, the strains of O. cf. siamensis exhibited a higher level of toxicity at 22°C and 25°C than at 16°C and 19°C, indicating an effect of temperature on the toxicity of Ostreopsis spp. [...]
Debusschere, Vincent. "Contributions méthodologiques à l’éco-conception des convertisseurs électromagnétiques d’énergie". Cachan, Ecole normale supérieure, 2009. http://tel.archives-ouvertes.fr/tel-00443702/fr/.
Minimizing environmental impacts of human activity represent a major objective of sustainable development considering resources depletion and the limited capabilities of the environment to adapt. Devices with better environmental performance require a specific design approach integrating credible environmental criteria. It is indeed by acting at the early phase of design that it is likely to provide the maximum flexibility to minimize environmental impacts of a product (or service). This method is called eco-design. In the field of eco-design, these works are conduct on applications of electrical engineering and more specifically of electromagnetic energy converters. These components have the distinction of consuming energy during use. This particularity implies a strong connection between the operating mode of the device and its life cycle design. This thesis propose in a first part an introduction to life cycle assessment and to the basic principles of eco-design. The methodological perspectives that these considerations open in the specific field of Electrical Engineering are then described. In a second part, three Electrical Engineering cases of increasing complexity are studied : a simplified single-phase transformer, a permanent capacitor single-phase induction machine with very short operating times (real commercial product) and finally a three-phase induction machine with optimized power supply. These applications are used to emphasize the principles of eco-design and are optimized regarding three environmental criteria : the gross energy requirement, the resources depletion and the global warming potential. In fact, taking into account other environmental impacts is identical in terms of methodology. In these studies, we show that it is interesting to optimize the design of these electromagnetic converters on life cycle, when their cumulative operating time is small compared to the total time of use. The amount of operating losses is also a parameter having a significant action on the results of eco-design. The setting of these applications is also subject to various sensitivity studies in order to determine more precisely the influence of the elementary energy costs, the choice of raw materials, etc. . Finally, we introduce the definition of an energy efficiency on life cycle more appropriate to an eco-design methodology
Marelle, Louis. "Modélisation régionale des polluants à courte durée de vie (aérosols, ozone) en Arctique". Electronic Thesis or Diss., Paris 6, 2016. https://accesdistant.sorbonne-universite.fr/login?url=https://theses-intra.sorbonne-universite.fr/2016PA066190.pdf.
The Arctic is increasingly open to human activity due to rapid warming, associated with decreased sea ice extent. This warming is due, in part, to the effect of short-lived atmospheric pollutants (aerosols, ozone). As a result, Arctic pollutant emissions should increase in the future, and their impacts might become significant compared to the now predominant source due to pollution transport from the mid-latitudes. In this thesis, regional simulations of the Arctic troposphere are performed with the WRF-Chem model, combined with new emission estimates for oil and gas extraction and shipping in the Arctic. The model is used to analyze two case studies from recent airborne measurement datasets: POLARCAT-France in 2008, ACCESS in 2012. First, I investigate an aerosol transport event from Europe to the Arctic in spring 2008, in order to improve our understanding of this major source of Arctic pollution. Second, I determine the air quality and radiative impacts of shipping emissions in Northern Norway in summer 2012, where most current Arctic shipping occurs. I use these results to validate modeled pollution, and to improve WRF-Chem for Arctic studies. The updated model is used to investigate the current (2012) and future (2050) impacts of Arctic shipping and Arctic gas flaring in terms of air quality and radiative effects. Results show that Arctic flaring emissions are and should remain a strong source of local black carbon aerosols, causing warming, and that Arctic shipping is already a strong source of aerosols and ozone during summer. In 2050, diversion shipping through the Arctic Ocean could become a major source of local surface aerosol and ozone pollution