Дисертації з теми "Cycle du carbone inorganique"
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Brunet, Frédéric. "Variations de la signature isotopique (delta)13 C du carbone inorganique dissous dans les rivières et les fleuves." Toulouse 3, 2004. http://www.theses.fr/2004TOU30228.
The scientific objective of this work is to better understand the riverine carbon transfers to the oceans and to identify the different biogeochemical processes controlling these transfers using carbon isotopic signature (d13C). In order to do that, 25 watersheds have been investigated in the world, going from small catchments to large river basins. The results emphasize the major control of CO2 degassing to the atmosphere and of organic carbon oxidation (allochtonous and autochtonous) on the riverine d13CDIC. The average isotopic signature d13CDIC of the inorganic carbon riverine flux into the oceans has been estimated in this study to be -11,8. Finally, a first approach of a numerical model (d-Carb) has been developed to simulate the d13CDIC evolution in rivers
Corbière, Antoine. "Variabilité interannuelle à décennale du cycle océanique du carbone dans le gyre subpolaire de l'Océan Atlantique Nord." Paris 6, 2008. http://www.theses.fr/2008PA066568.
Nkoue-ndondo, Gustave-Raoul. "Le cycle du carbone en domaine tropical humide : exemple du bassin versant forestier du Nyong au sud Cameroun." Toulouse 3, 2008. http://thesesups.ups-tlse.fr/476/.
Spatial and temporal follow ups of carbon contents and its isotopic signature d13C in the Nyong river basin allow on one hand, at a local scale (small experimental catchment of Mengong), to identify the carbon sources, and on the other hand, at a regional scale (Nyong river basin), to understand the biogeochemical processes which control the carbon transformations and exchanges between the different reservoirs during the transfer from upstream to downstream. In these wet tropical ecosystems, the swampy soils of bottom valley low marshes present in surface a thick organic carbon rich horizon (12 to16 %), with isotopic signatures d13C of -29 ‰ in equilibrium with C3 plants (-32 ‰ to -28 ‰). During the rainy season, the mineralization of organic matter and the leaching of swampy areas are responsible of hight DOC contents (until 38 mg / L) in streamwaters, strong pCO2 and impoverished d13CDIC isotopic signatures (-20 ‰ on average). During the dry season, the shrinkage of the swampy zones facilitates the supply of streams by low DOC content (< 1mg / L) and enriched d13CDIC (d13CDIC until 7 ‰%) grounwaters. The carbon flux into the ocean is estimated to 1. 2*106 t C / year, i. E. 6. 24 t C/km2. Year, of which 80 % of DOC, 8 % of POC and 12 % of DIC. During the transfer from upstream to downstream, a DOC decrease of 33 % is observed in relation with oxidation processes. The resulting strong pCO2 facilitate the CO2 degassing towards the atmosphere, estimated for the Nyong river system at 2. 3* 105 t C / year. This CO2 degassing is accompanied by an isotopic enrichment of about 4 ‰. The weathering of silicate minerals by organic acids leads to a surplus of Ca+Mg (0. 5 < Ca+Mg / HCO3- < 2. 2) with regard to a natural weathering pathway by the carbonic acid (Ca+Mg / HCO3- = 0. 5). .
Koffi, Kouakou Urbain. "Distribution des paramètres du carbone et du flux de CO2 à l'interface air - mer dans l'Est de l'Atlantique tropical." Phd thesis, Université Pierre et Marie Curie - Paris VI, 2011. http://tel.archives-ouvertes.fr/tel-00945786.
Riquier, Laurent. "Perturbations des environnements marins, à la limite Frasnien-Famennien (Devonien Terminal) : apport de la géochimie inorganique et du magnétisme des roches." Lille 1, 2005. https://ori-nuxeo.univ-lille1.fr/nuxeo/site/esupversions/f1c218ee-6fde-4031-8185-25754832f1cb.
Ce phénomène d'altération a vraisemblablement été favorisé par un climat particulièrement chaud et humide. Durant l'épisode de dépôt de l'horizon Kellwasser supérieur, l'appauvrissement en oxygène résulterait de la stratification des eaux dans les environnements profonds, due à une diminution de la circulation océanique, causée par un confinement plus important des bassins. Cette stratification a été accrue durant la période de haut niveau marin associée à l'horizon Kelhvasser supérieur. Les eaux anoxiques ont pu se répandre dans les environnements de plates-formes à la faveur de la montée eustatique. La mise en place de conditions anoxiques, voire localement euxiniques, a favorisé la diffusion des nutriments libérés par la reminéralisation de la matière organique. Ces nutriments ont pu rejoindre épisodiquement les eaux de surface, à la faveur d'interruptions temporaires de la stratification des eaux, et ainsi intensifier la productivité primaire. Il est proposé que cette période de stockage accrue de carbone organique dans les sédiments ait fortement perturbé le cycle du carbone à long terme, conduisant, au final, à une chute notable de la pression de CO2 atmosphérique et au refroidissement du climat à la base du Famennien. Ainsi, ces travaux suggèrent que la formation des horizons Kellwasser résulte de la conjonction de divers' phénomènes, comprenant la tectonique s. L. ,l'évolution des végétaux, la physiographie des océans, la productivité marine, le tout en interactions directes et indirectes avec le climat
Duval, Bastien. "Ecodynamics of trace metals and metalloids in Pyrenean lakes in relation to climate change and anthropogenic pressure." Thesis, Pau, 2020. http://www.theses.fr/2020PAUU3046.
The management and conservation of Pyrenean high mountain lakes within the current context of climate change and increasing anthropogenic pressure require detailed knowledge of their biogeochemical functioning. In this doctoral thesis, five sampling campaigns were carried out (2017-2019) in more than 20 alpine lakes. The analysis of water samples allowed us to study the occurrence, the depth profiles, the geographical distribution and the seasonal trends of a large array of physico-chemical and biogeochemical parameters. Specifically, the cycle of carbon dioxide (CO2) and the fate of Potentially Harmful Trace Elements (PHTEs) were investigated. The mercury (Hg) was specially studied through the development of an analytical procedure for the measurement of trace concentrations in natural waters and through biogeochemical investigations on the distribution and the fate of Hg species in the water column, as well as in sediment archives.The new and robust procedure developed in this work to measure the total alkalinity (TA) and the dissolved inorganic carbon (DIC) allowed us to determine the other two parameters of the CO2 system, the pH and the fugacity of CO2 (fCO2). The bedrock characteristics of the watershed appear to be the most important parameters influencing the acid status of the studied lakes. Moreover, obtained fCO2 values indicate that lakes are sources of CO2 for the atmosphere.The measurement of various physico-chemical parameters allowed us to discriminate and classify the studied lakes according to their water geochemistry, highlighting the importance of the trophic status of the lakes, the geological background and the atmospheric inputs. The occurrence, sources and behaviour of the PHTEs were investigated with evidence of a contrast between geological and atmospheric inputs. Intensive monitoring revealed some PHTEs to be highly sensitive to environmental changes such as temperature and redox conditions.Monitoring natural concentrations of total Hg in aquatic systems remains a difficult challenge and there is a need for the development of low cost and easy handling analytical methods. The method for analysis of trace Hg concentrations developed and optimized in this work was successfully operational and exhibits a suitable limit of detection and an excellent reproducibility. Hg speciation results in the water column demonstrated the pristine state and the dynamic of the Pyrenean lakes. The homogeneity in the non-gaseous total Hg concentrations in the studied lakes confirmed the absence of local sources and the potential use of these ecosystems as sentinels of regional to global Hg contamination. While inorganic mercury (iHg) did not show seasonal variations, monomethylmercury(MMHg) was significantly higher in autumn 2018 and dissolved gaseous mercury (DGM) varied strongly within and among lakes. In-situ experiments confirmed the conditions that promote Hg methylation (stratified anoxic waters), demethylation and photoreduction (intense UV light).The historical Hg record in sediment archives highlighted temporal trends in Hg accumulation rates (HgARs) with a progressive increase since the 16th Century and the industrialization, mirroring the Hg production in Almadén mines (Southern Spain). Besides, Hg stable isotopes allow the identification of distinct anthropogenic sources as well as past climate variability.Overall, environmental changes in lake ecosystems, induced by either climatic conditions (temperature, light intensity) or anthropogenic pressure (atmospheric inputs, eutrophication, atmospheric CO2) are likely to produce significant impacts among CO2, specific PHTEs and Hg biogeochemical cycles in mountainous ecosystems
Furla, Paola. "Mécanismes de transport de carbone inorganique dans l'association symbiotique Cnidaire-dinoflagélle." Aix-Marseille 2, 1999. http://www.theses.fr/1999AIX22095.
Granier, Jean-Marie. "Transport du carbone inorganique en solution expérimentation et modélisation à différentes échelles... /." Grenoble 2 : ANRT, 1988. http://catalogue.bnf.fr/ark:/12148/cb37614037w.
Ndiaye, Mbalo. "Transfert de CO2 et stratégie d' apport du carbone inorganique en photobioréacteur." Thesis, Nantes, 2016. http://www.theses.fr/2016NANT4042/document.
Photobioreactors (PBR) applications for photosynthetic microorganisms cultivation, are varied and promising. Optimazing culture conditions is necessary in order to ensure economically viable PBR operation by ensuring adequate CO2 intake for all microorganisms at any point of the reactor while limiting losses by degassing. This study more specifically focuces on CO2 mass transfer from gas phase to liquid phase. Computational fluid dynamics CFD is used to achieve a fine analysis of the interactions that take place in these systems in order to have a better understanding of the phenomena governing their operation and predict the spatial and temporal distribution of the dissolved species and gas/liquid mass transfer performances. The numerical study of gas/liquid transfer using dynamic method with O2 and with CO2 shows that apparent kLa values obtained with O2 is higher. Unlike oxygen, CO2 bubbles depleted significantly during their rising in the liquid which results in a significant decrease of the exchange potential and therefore the apparent kLa. Thus photobioreactor scale-up with kLa of CO2 estimated from dynamic method with O2 could lead to an overestimation of the gas/liquid mass transfer capabilities at large scale. Moreover, PBR simulation with microalgae using CFD code shows that it is possible to bring dissolved CO2 sufficiently and homogeneously in a 100 L airlift PBR. In addition, conditions to control pH are determined for moderate CO2 concentrations in the gas phase
Beuf, Laurent. "Recherche des gènes impliqués dans l'assimilation du carbone inorganique chez Synechocystis PCC 6803." Aix-Marseille 2, 1993. http://www.theses.fr/1993AIX22078.
Rivé, Karine. "Origine du carbone inorganique dissous dans les rivières des zones volcaniques : le point de vue des isotopes du carbone." Paris 7, 2008. http://www.theses.fr/2008PA077222.
On Earth, chemical weathering of silicate rocks is one of the mechanisms which consumes CO₂. All of these processes could be part of a negative feedback loop exerted on the Earth's climate, which would allow its regulation over geological time. Volcanic rocks have an important role since they are responsible for 30 pourcents of total CO₂ by weathering. The main challenge of this study is to identify the origin of CO₂ involved in the reactions of weathering of rocks of four active volcanic areas: the West Indies, Reunion, the Iceland and the Massif Central. In this aim, the delta13C of dissolved inorganic carbon (DIC) and riverine major ions were combined. In a first step, a reliable method of sampling and analysis of delta¹³C DIC has been developed. The analyse of nearly 200 samples from rivers, soil and solutions hydrothermal springs has highlighted that the magmatic CO₂ contributes significantly to the weathering of volcanic rocks, or even that it represents most of the CO₂ consumed by weathering in Iceland and Reunion, the other main reservoir of CO2 being biogenic CO₂. In addition, magmatic CO₂ appears to contribute to the weathering in different ways: either through hydrothermal contributions, or as diffuse magmatic CO₂. Both types of CO₂ would be associated with different schemes of weathering: soil type regime at low temperature, and the hydrothermal regime. The consequence of these observations is an overstatement of the rate of atmospheric CO₂ previously calculated by the mean of major ions in active zones. There seem to be a link between the proportion of CO₂ magmatic and rates of chemical weathering of rocks, which would indicate a control of weathering of active volcanic areas by magmatic CO₂. This underlines the need for measures of delta¹³CDic on a global scale, particularly in volcanic areas
Martinez, Mathieu. "Spéciation et isotopie du soufre inorganique en milieu aqueux." Thesis, Pau, 2019. http://www.theses.fr/2019PAUU3009/document.
Sulfur is present in the hydrosphere at oxidation states ranging from sulfate (+VI) to sulfide (-II) and including many species at intermediate oxidation states, such as elemental sulfur (0), thiosulfate (-I, V) and sulfite (IV). These species in particular are considered as important intermediates in biological and abiotic reactions (oxidation, reduction or disproportionation) involving sulfur and are frequently coupled to the biogeochemical cycles of carbon, nitrogen, oxygen and iron.Sulfur cycle processes are studied by measuring the concentrations of different species containing sulfur (speciation analysis) and by measuring their respective isotope ratios (isotopic analysis). Analytical difficulties are frequently encountered because sulfur species, especially intermediate valence species, are present in low concentrations and are difficult to isolate. Thus, the isotope ratios of intermediate valence species are rarely determined. Methods for measuring isotope ratios of inorganic sulfur species, particularly the least abundant intermediate species, would be a great assistance in deciphering sulfur cycle processes.In this context, this thesis work was devoted to the development of analytical strategies combining speciation and isotopic analysis of sulfur, in order to measure sulfur isotope ratios of several inorganic species that can be simultaneously present in liquid samples. First, a speciation method for quantifying sulfite, sulfate and thiosulfate by liquid chromatography coupled to high-resolution inductively coupled plasma mass spectrometer (LC-HR-ICP-MS) was set up. Then, an off-line approach was developed for the isotopic analysis of sulfide, sulfate and thiosulfate. It consisted of a sample preparation by sequential precipitation of the sulfur species, followed by elemental analyzer coupled to isotope ratio mass spectrometer (EA-IRMS) analysis. This method made it possible to determine the δ34S values of sulfide, sulfate and thiosulfate with measurement uncertainties below 0.5 ‰ for water samples containing at least 27 µg of sulfur. This method has been applied to the study of spring waters and deep aquifer waters and the monitoring of isotopic fractionation of sulfur in a culture of sulfate-reducing bacteria.Moreover, an on-line analytical method coupling anionic separation and detection by multicollector inductively coupled plasma mass spectrometer (LC-MC-ICP-MS) has been developed for the determination of δ34S values of sulfite, sulfate and thiosulfate. This method allowed us to determine δ34S of sulfite, sulfate and thiosulfate for water samples containing as little as 1 µg of sulfur per species with measurement uncertainties below 0.6 ‰
Brunet, Frédéric. "VARIATIONS DE LA SIGNATURE ISOTOPIQUE δ13C DU CARBONE INORGANIQUE DISSOUS DANS LES RIVIÈRES ET LES FLEUVES". Phd thesis, Université Paul Sabatier - Toulouse III, 2004. http://tel.archives-ouvertes.fr/tel-00184081.
Cachier-Rivault, Hélène. "Approche isotopique du cycle atmosphérique du carbone particulaire." Grenoble 2 : ANRT, 1987. http://catalogue.bnf.fr/ark:/12148/cb376035474.
Tounsi, Khoudhir. "Le cycle du carbone dans l'Océan atlantique tropical." Toulouse 3, 1990. http://www.theses.fr/1990TOU30233.
Cachier-Rivault, Hélène. "Approche isotopique du cycle atmospherique du carbone particulaire." Paris 7, 1987. http://www.theses.fr/1987PA077061.
Labbe, Espéret Christiane. "Modélisation et conceptualisation : l'exemple du cycle du carbone." La Réunion, 2002. http://elgebar.univ-reunion.fr/login?url=http://thesesenligne.univ.run/02_07_Labbe_Esp.pdf.
Kirstetter, Anne-Sophie. "Etude de la fixation du carbone inorganique chez la levure pour la production industrielle de molécules d’intérêt." Thesis, Université Paris-Saclay (ComUE), 2016. http://www.theses.fr/2016SACLC015/document.
White biotechnologies have been developing quickly during the last decades, aiming at replacing chemical syntheses by biological processes for the industrial production of target compounds. In this context, the implementation of anaplerotic reactions in the metabolism is of great interest, since those reactions allow both production of dicarboxylic acids and direct fixation of inorganic carbon. This work is about the development of a metabolic engineering strategy using inorganic carbon fixation reactions to produce malic acid, a compound with various industrial applications. The yeast Saccharomyces cerevisiae was chosen as a host for its convenient use in industrial processes and the availability of genetic tools. The approach developed to produce malic acid is based on the overexpression of Escherichia coli phosphoenolpyruvate carboxylase (PEPC), S. cerevisiae peroxysomale malate dehydrogenase relocated in the cytosol (MDH) and Schizosaccharomyces pombe dicarboxylic acid carrier. A recombinant yeast strain expressing those three genes was obtained and characterised in shake-flasks experiments, involving more specifically calcium carbonate as an inorganic carbon source. Those experiments showed an enhancement of the malate production in the presence of calcium carbonate and allowed to obtain a concentration of 2.5 g/L from 50 g/L glucose, for a maximal yield of 0.046 gram malate per gram glucose. Fermentation experiments were performed in a 5 L bioreactor in the presence of air or 5% CO2 enriched air; they confirmed the positive effect of inorganic carbon addition as CO2 on malate production. A malate concentration of 1.46 g/L from 50 g/L glucose was obtained, giving a yield of 0.029 gram malate per gram glucose. Intermediate recombinant strains expressing PEPC and MDH were also characterised, for ethanol production, as they seemed to give increased ethanol yields, probably due to a transhydrogenase effect. Shake flasks and bioreactors experiments did unfortunately not confirm the yield improvement
Garnier, Jean-Marie. "Transport du carbone inorganique en solution : expérimentation et modélisation à différentes échelles (2.10⁻¹ , 10 et 10² à 10³ m)." Paris 11, 1988. http://www.theses.fr/1988PA112391.
Mariotti, Véronique. "Le cycle du carbone en climat glaciaire : état moyen et variabilité." Versailles-St Quentin en Yvelines, 2013. http://www.theses.fr/2013VERS0071.
Atmospheric CO2 variations, of around 100 ppm, between glacial and interglacial climates, and 14C variations, are not well understood. This is also the case for the 20 ppm variations of CO2 associated to abrupts events at glacial times. Combining both models and data, I have shown (1) that the sinking of brines mechanism - pockets of salt rejected by sea-ice formation - around Antarctica, likely able to explain glacial-interglacial CO2 variations according to previous studies, could also explain the 14C, (2) that an oscillation of this mechanism could also induce the 20 ppm variations of CO2, during abrupt events, (3) that marine productivity was correctly simulated on the glacial-interglacial time scale and during abrupts events and (4) that for both kinds of variations, it had a limited role on CO2
Bouttes, Nathaëlle. "L’évolution du cycle du carbone au cours du Quaternaire." Paris 6, 2010. http://www.theses.fr/2010PA066376.
Halvick, Philippe. "Contribution théorique à l'étude de la dynamique des réactions indirectes du type A + BC → AB + C : application à l'étude de la réaction C(3P)+ NO (X2PI)→CN (X2sigma+) + O(3P)." Bordeaux 1, 1987. http://www.theses.fr/1987BOR10616.
Gillon, Marina. "Etude des modes d'acquisition de la signature isotopique en carbone des eaux souterraines et préservation du signal environnemental lors de la recharge des aquifères." Paris 11, 2008. http://www.theses.fr/2008PA112038.
The management of groundwater needs the estimation of the water residence time in aquifers, that can be done through the measurement of 14C radioactive decay of the Total Dissolved Inorganic Carbon (TDIC). This approach requires the knowledge of the TDIC 14C initial activity in recharge water. The groundwater mineralisation occurs in the Unsaturated Zone (UZ), where water interacts with CO2 and carbonates (if existing). We focus here on these interactions between both CO2, TDIC and carbonates. Two UZ have been investigated in France: the carbonate-free Fontainebleau sands and the carbonated Astian sands. Each site is equipped with a specific and experimental equipment to collect groundwater, UZ water, gas and solid matrix (organic matter and carbonate). The field-data are completed by a numeric approach in order to evaluate the different factors that define the CO2 isotopic composition at the bottom of the UZ. The 13C of CO2 depends on the mean 13C of produced CO2, the amount of produced CO2 and the diffusion coefficient of CO2. Subsurface seasonal variations of 13C disappear with depth. Before 1950, the 14C activity of CO2 can be assumed equal to atmospheric 14C level. After 1950, due to the atmospheric nuclear test, it depends on 14C activity of young organic matter and atmospheric CO2. The presence of carbonates leads to a 13C-enrichment of and a 14C-depletion of CO2 with depth, depending on the carbonate precipitation/dissolution flux, the amount of produced CO2 and the diffusion coefficient of CO2
Bertucci, Anthony. "Etudes moléculaire et physiologique des mécanismes permettant l'utilisation du carbone inorganique chez le corail Scléractiniaire Stylophora pistillata (Esper, 1797)." Thesis, Aix-Marseille 2, 2010. http://www.theses.fr/2010AIX22112/document.
Coral reefs edification is based on the formation of a calcium carbonate skeleton byscleractinian corals. Many of these reef-building corals establish a symbiotic association with photosynthetic Dinoflagellates. Both processes involve the transport and utilization of inorganic carbon (Ci) coming from seawater for photosynthesis, and from animal metabolismfor calcification. This work focused on the molecular and physiological study of poorlyknown mechanisms that allow the utilization of Ci.Despite the importance of bicarbonate transport, no transporter has been characterized and their role in coral physiology is only suggested by pharmacological experiments. We have cloned a gene encoding a bicarbonate transporter in the coral Acropora sp. The conversion of this bicarbonate into CO2 for photosynthesis is mediated by the acidification of the are asurrounding the Dinoflagellate in the animal cell. This is performed by a P type H+-ATPasethat we characterized here. This is the first gene with a symbiosis-dependent expression in the symbiont.This work also allowed the cloning and the localization of two carbonic anhydrases (CA).The first one is involved in calcification, the second one plays a role in the intracellular pHregulation and the CO2 / HCO3- equilibrium. A pharmacological study of these two enzymes identified inhibitor and activator compounds that have been then used in physiology experiments. This last approach represents a more accurate study of the role of CAs incalcification
Suan, Guillaume. "Changements climatiques, cycle du carbone et production carbonatée au Pliensbachien-Toarcien." Lyon 1, 2008. http://www.theses.fr/2008LYO10194.
The relationships between changes in climate, carbon cycling and carbonate production in the Pliensbachian-Toarcian are investigated using geochemical, sedimentological and paleontological data acquired in Portugal, Italy and northern Siberia. Reconstructions of seawater temperatures inferred from the oxygen isotope composition of brachiopod shells reveal successive and marked cooling and warming episodes. The analysis of calcareous nannofossils and carbonate contents indicate that warming episodes corresponded to drastic carbonate production decline and extinction in both neritic and pelagic settings. Global variations in carbon isotope ratios indicate that warming events were probably controlled by atmospheric CO2 concentrations, likely caused by episodes of intense volcanism in South Africa and in Antarctica
Racapé, Virginie. "Étude de la distribution du δ13CDIC dans l’océan et évaluation de la composante anthropique du CO2". Paris 6, 2013. http://www.theses.fr/2013PA066791.
The isotopic composition of dissolved inorganic carbon (δ13CDIC) in the ocean is a useful semi-conservative tracer of the carbon cycle to study the anthropogenic CO2 component and paleo-circulation. The mean annual large scale distribution of this tracer is now relatively well documented in surface and at depth, but the temporal variability still needs to be completed. Based on new observations collected since the end of 90s until 2012, this study describes and interprets the seasonal, interannual to decadal variability of the δ13CDIC in three oceanic regions: the North-Atlantic subpolar gyre (NASPG), the gulf of Guinea and the Southwestern and Southern Indian Ocean. In the surface waters of these regions, the δ13CDIC seasonal amplitude varies from 0‰ to 1‰ and depends on the local balance between the biological activity and the ocean dynamics. Negligible in the short-term, the air-sea CO2 exchange includes a large anthropogenic contribution that changes the δ13CDIC in the long term, but could be masked (Indian ocean) or increased (NASPG) by the natural variability. For the global carbon budget, the decrease in δ13CDIC due to the anthropogenic carbon (Cant) uptake in the surface ocean, the so-called oceanic 13C Suess effect, provides additional information to better discriminate the natural variability from the anthropogenic signal. Based on the extended multi-linear regression (eMLR), the oceanic 13C Suess effect and the anthropogenic DIC changes have been estimated together in key regions for the Cant storage: the NASPG and the Southwestern Indian Ocean. These results revealed an anthropogenic change around -0. 013‰ (µmol kg-1)-1 in NASPG, which attests to the low renewal of the Labrador sea-water since the beginning of 90s. In the Indian Ocean, the anthropogenic carbon change, around -0. 021‰ (µmol kg-1)-1, highlights a steady residence time of surface waters. These results are compared to NEMO-PISCES model of IPSL. The δ13CDIC seasonal cycle is under-estimated 2 or 3 times by the model but the anthropogenic signal evaluation is comparable to the direct estimations obtained by this study
Amiotte, Suchet Philippe. "Cycle du carbone, érosion chimique des continents et transferts vers les océans /." Strasbourg : Université Louis Pasteur, Institut de géologie : Centre de Géochimie de la surface, CNRS, 1995. http://catalogue.bnf.fr/ark:/12148/cb35839549z.
Cadule, Patricia. "Modélisation des interactions entre le système climatique et le cycle du carbone." Paris 6, 2009. http://www.theses.fr/2009PA066142.
Mihalopoulos, Nikolaos. "Contribution à l'étude du cycle biogéochimique de l'oxysulfure de carbone dans l'atmosphérique." Paris 7, 1989. http://www.theses.fr/1989PA077162.
Amiotte, Suchet Philippe. "Cycle du carbone, erosion chimique des continents et transferts vers les oceans." Université Louis Pasteur (Strasbourg) (1971-2008), 1994. http://www.theses.fr/1994STR13061.
Friedlingstein, Pierre. "Modélisation du cycle du carbone biosphérique et étude du couplage biosphère-atmosphère." Doctoral thesis, Universite Libre de Bruxelles, 1995. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/212604.
Garnier, Matthieu. "Allocation du carbone et métabolisme azoté chez l’haptophyte Tisochrysis lutea." Nantes, 2016. https://archive.bu.univ-nantes.fr/pollux/show/show?id=014f2bc2-0d6e-41d6-af47-3bbc37ce8987.
The aim of this thesis is to improve knowledge on mechanisms involved in the response to nitrogen limitation and in lipid accumulation in the microalgae haptophyte Tisochrysis lutea. The wild type strain and a lipid accumulating mutant strain were grown under different nitrogen limitation and starvation and analyzed by functional genomics. Four genes of high-affinity nitrate/nitrite transporter (Nrt2) were identified and characterized to reveal the mechanisms involved in mineral absorption in this species. Transcriptomes of both strains were sequenced and proteins affected by nitrogen starvation and differentially expressed between the two strains were identified. We so identified the functions regulated by nitrogen deficiency and potentially involved in the accumulation of storage lipids. The responses of both strains to thin variations of nitrogen limitation were studied. The results of high-throughput proteomic analyzes suggest that the lipid-accumulation in the mutant strain is the result of carbon metabolism impacted overall, this spurred on signaling mechanisms. Two proteins have been studied since probably involved in carbon and nitrogen remobilization from amino acids catabolism during nitrogen limitation. This work increases knowledge on haptophytes, and brings assumptions on metabolic key involved in nitrogen limitation and carbon allocation in microalgae
Sellin, Murielle. "Complexes octaédriques du fer porteurs de deux ligands alcoxycarbonyle, alkyloxalyl, acétyle ou pyruvoyle : couplage carbone-carbone et isomérie chaîne-cycle." Brest, 1995. http://www.theses.fr/1995BRES2026.
Piccoli, Francesca. "High-pressure carbonation : a petrological and geochemical study of carbonated metasomatic rocks from Alpine Corsica." Thesis, Paris 6, 2017. http://www.theses.fr/2017PA066448/document.
The balance between the carbon input in subduction zone, mainly by carbonate mineral-bearing rock subduction, and the output of CO2 to the atmosphere by volcanic and metamorphic degassing is critical to the carbon cycle. At fore arc-subarc conditions (75-100 km), carbon is thought to be released from the subducting rocks by devolatilization reactions and by fluid-induced dissolution of carbonate minerals. All together, devolatilization, dissolution, coupled with other processes like decarbonation melting and diapirism, are thought to be responsible for the complete transfer of the subducted carbon into the crust and lithospheric mantle during subduction metamorphism. Carbon-bearing fluids will form after devolatilization and dissolution reactions. The percolation of these fluids through the slab- and mantle-forming rocks is not only critical to carbon cycling, but also for non-volatile element mass transfer, slab and mantle RedOx conditions, as well as slab- and mantle-rock rheology. The evolution of such fluids through interactions with rocks at high-pressure conditions is, however, poorly constrained. This study focuses on the petrological, geochemical and isotopic characteristic of carbonated-metasomatic rocks from the lawsonite-eclogite unit in Alpine Corsica (France). The study rocks are found along major, inherited lithospheric lithological boundaries of the subducted oceanic-to-transitional plate and can inform on the evolution of carbon-bearing high-pressure fluids during subduction. In this work, it will be demonstrated that the interaction of carbon-bearing fluids with slab lithologies can lead to high-pressure carbonation (modeled conditions: 2 to 2.3 GPa and 490-530°C), characterized by silicate dissolution and Ca-carbonate mineral precipitation. A detailed petrological and geochemical characterization of selected samples, coupled with oxygen, carbon and strontium, neodymium isotopic systematic will be used to infer composition and multi-source origin of the fluids involved. Geochemical fluid-rock interactions will be quantified by mass balance and time-integrated fluid fluxes estimations. This study highlights the importance of carbonate-bearing fluids decompressing along down-T paths, such as along slab-parallel lithological boundaries, for the sequestration of carbon in subduction zones. Moreover, rock-carbonation by fluid-rock interactions may have an important impact on the residence time of carbon and oxygen in subduction zones and lithospheric mantle reservoirs as well as carbonate isotopic signatures in subduction zones. Lastly, carbonation may modulate the emission of CO2 at volcanic arcs over geological time scales
Maffre, Pierre. "Interactions entre tectonique, érosion, altération des roches silicatées et climat à l'échelle des temps géologiques : rôle des chaînes de montagnes." Thesis, Toulouse 3, 2018. http://www.theses.fr/2018TOU30287.
This thesis explores how orogenies may affect the Earth climate through the quantification of the interactions between climate dynamics, continental erosion, silicate rock weathering rate and geological carbon cycle. The first chapter describes the mechanisms linking the continental topography and its impacts on the atmospheric and oceanic circulations, with emphasis on the thermohaline circulation. The second chapter compares the effects on continental weatherability of climate dynamics and erosional changes related to the presence of mountains. The third chapter describes a dynamic model of regolith designed for global scale simulations, and describes its transient behavior, as well as its response to a CO2 degassing. Finally, the last chapter presents a numerical model of the continental isotopic cycle of lithium, so that its reliability as a proxy of the past weathering can be tested. The model explores the case study of the Amazon lithium cycle
Paris, Guillaume. "Réponses du système Terre aux perturbations géologiques du cycle du carbone. Isotopes du carbone, modelisation et apport des isotopes du bore." Phd thesis, Institut de physique du globe de paris - IPGP, 2009. http://tel.archives-ouvertes.fr/tel-00655630.
Paris, Guillaume. "Réponses du système Terre aux pertubations géologiques du cycle du carbone : isotopes du carbone, modélisation et apport des isotopes du bore." Paris, Institut de physique du globe, 2009. http://www.theses.fr/2009GLOB0017.
Studying geological carbon cycle disruption helps to further understand modern carbon cycle and to better apprehend the consequences of the current increase in atmospheric CO2. Specifically, geological crisis highlight the reaction ability of the environment to stressful situation. We used a multi‐proxy approach to study the Triassic‐Jurassic (TJ) boundary events. This transition period is characterized by a succession of two carbon isotopes negative excursions (CINEs) in sections from Tethyan realm. Through GEOCLIM modeling, we show that the Central Atlantic Magmatic Province (CAMP) likely generated the carbonate production crisis observed during the first CINE provided that emplacement is modeled as a succession of intense short‐lived pulses (<400y) as suggested by recent studies. If emitted mantellic carbon is isotopically light (<‐20‰), CAMP emplacement also generated the first CINE. We investigated British and Austrian sections through carbon and nitrogen isotopes for local consequences of global TJ transition events (CAMP emplacement and sea level variations). We showed that the biological pump is perturbated by eutrophication and blooms of prokaryotic organisms. A supplementary tool is provided by boron isotopic composition (δ11B) of carbonates that record seawater pH. However, inter‐laboratory discrepancies prevent this tool from being broadly used. Here, we present a recently developed injection device for boron isotopes analysis on MC‐ICP‐ MS and use it for studying boron isotopes on Middle Jurassic limestones during a time of carbonate production perturbation. Nevertheless, we remain speculative in our interpretation for carbonate δ11B values record both seawater pH and δ11B values. As a consequence, we initiated the reconstruction of Phanerozoic seawater δ11B values by measuring δ11B values in marine halites. The reconstructed values exhibit clear variations through time that are related to geodynamic parameters. This study underlines the necessity for multi‐proxy approach to bring new light on atmospheric pCO2 and seawater chemical composition
Maisongrande, Philippe. "Modélisation du cycle du carbone dans la biosphère terrestre : intégration de données satellitaires." Toulouse, INPT, 1996. http://www.theses.fr/1996INPT131H.
Barral, Cuesta Abel. "The carbon isotope composition of the fossil conifer Frenelopsis as a proxy for reconstructing Cretaceous atmospheric CO2." Thesis, Lyon, 2016. http://www.theses.fr/2016LYSE1148.
The Cretaceous was a period characterized by strongly marked climate change and major carbon cycle instability. Atmospheric CO2 has repeatedly been pointed out as a major agent involved in these changing conditions during the period. However, long-term trends in CO2 described for the Cretaceous are not consistent with those of temperature and the large disturbance events of the carbon cycle described for the period. This raises a double question of whether descriptions of the long-term evolution of atmospheric CO2 made so far are accurate or, if so, atmospheric CO2 was actually a major driver of carbon cycle and climate dynamics as usually stated. In this thesis the close relationship between the carbon isotope composition of plants and atmospheric CO2 is used to address this question. Based on its ecological significance, distribution, morphological features and its excellent preservation, the fossil conifer genus Frenelopsis is proposed as a new plant proxy for climate reconstructions during the Cretaceous. The capacity of carbon isotope compositions of Frenelopsis leaves (d13Cleaf) to reconstruct past atmospheric CO2, with regards to both carbon isotope composition (d13CCO2) and concentration (pCO2), is tested based on materials coming from twelve Cretaceous episodes. To provide a framework to test the capacity of d13Cleaf to reconstruct d13CCO2 and allowing for climate estimates from carbon isotope discrimination by plants (?13Cleaf), a new d13CCO2 curve for the Cretaceous based on carbon isotope compositions of marine carbonates has been constructed. Comparison with d13Cleaf-based d13CCO2 estimates reveals that although d13CCO2 and d13Cleaf values follow consistent trends, models developed so far to estimate d13CCO2 from d13Cleaf tend to exaggerate d13CCO2 trends because of assuming a linear relationship between both values. However, given the hyperbolic relationship between ?13Cleaf and pCO2, by considering an independently-estimated correction factor for pCO2 for a given episode, d13Cleaf values may be a valuable proxy for d13CCO2 reconstructions. ?13Cleaf estimates obtained from d13CCO2 and d13Cleaf values were used to reconstruct the long-term evolution of pCO2. The magnitude of estimated pCO2 values is in accordance with that of the most recent and relevant model- and proxy-based pCO2 reconstructions. However, these new results evidence long-term drawdowns of pCO2 for Cretaceous time intervals in which temperature maxima have been described
Aumont, Olivier. "Etude du cycle naturel du carbone dans un modele 3d de l'ocean mondial." Paris 6, 1998. http://www.theses.fr/1998PA066396.
Kuppel, Sylvain. "Assimilation de mesures de flux turbulents d'eau et de carbone dans un modèle de la biosphère continentale." Versailles-St Quentin en Yvelines, 2012. http://www.theses.fr/2012VERS0041.
Assimilating terrestrial ecosystem data is an approach increasingly used to fill the gap between experimental observations and the ecophysiological theory as embodied in process-based land surface models. In this thesis, we have sought to use the information content of eddy covariance measurements of net carbon dioxide (NEE) and latent heat (LE) fluxes made at the sites of the FLUXNET global network, aiming at optimizing key parameters of the ORCHIDEE vegetation model and at refining the uncertainty budget. A Bayesian statistical approach has been chosen, so as to account for prior knowledge of the uncertainties related to the model parameters, the model equations, and the measurements. The major line of work has been to develop a data assimilation method where observations from several flux sites are simultaneously used as a constraint, in order to optimize a unique set of parameters considered as generic within a given class of ecosystem. We found that this multi-site approach significantly improves the model-data agreement at seasonal and annual time scales, with performances fairly similar to those brought by site-scaled, independently optimized parameters (single-site approach). We notably discuss the fact that the multi-site parameters’ values are not always a mere average of their single-site counterparts. Making use complementary data, we also evaluated the ability of the multi-site optimizations to improve the simulation of the gross carbon fluxes (photosynthesis and respiration) at the site scale, while at the global scale we considered the modeled phenology of the leaf cover and the seasonal cycle of the atmospheric CO2 concentration. Within our methodological developments, we have also proposed a technique to infer the statistical structure of the error stemming from inadequate and/or missing process representations in a global vegetation model such as ORCHIDEE. Focusing on net carbon fluxes, our results suggest that this « model error » deserves an explicit representation in the uncertainty budget inherent to carbon cycle modeling
Para, Julien. "Etude de la Matière Organique Dissoute Chromophorique et du rayonnement solaire (UV-visible) dans les eaux de surfaces côtières méditerranéennes et articques." Thesis, Aix-Marseille 2, 2011. http://www.theses.fr/2011AIX22041/document.
To understand, characterize, and predict the evolution of oceanic biogeochemical cycles in relation to the global climate change, it is necessary to better understand the dynamics of organic matter (OM). In this context, the overall objective of this thesis was to get more insights chromophoric dissolved fraction of OM (CDOM) dynamics in surface Mediterranean and Arctic coastal waters and to determine the impact on attenuation of ultraviolet (UVR) and visible (PAR) underwater radiation. For this, the study of optical properties of absorbance and fluorescence of CDOM, coupled with atmospheric and underwater radiometric measurements, were made during a seasonal cycle in the Bay of Marseille (SOFCOM station), and in the Beaufort Sea during summer 2009. The Bay of Marseilles is characterized by low amounts of CDOM (aCDOM(350) = 0.10 ± 0.02 m-1), particularly in end summer stratification period due to the intensity of the solar irradiance, enriched in UVR-B, which degrades and bleaches CDOM (SCDOM = 0.023 ± 0.003 nm-1). In this highly urbanized coastal area, the dynamics of CDOM are driven by biotic processes (in situ biological production and within the Rhône River plume) and abiotic (photo-bleaching and mixing). Our results showed that CDOM is mostly of autochthonous origin, even during Rhône plume intrusion events (photo-degradation of terrestrial CDOM during the transit). During bloom periods, the CDOM consists mainly of a recent type protein (peak T), which preferentially absorbs in the short UVR. These pulses of recent CDOM are superimposed on a persistent background of CDOM mainly composed of aged material, humic-type (peaks M and C), which absorbs UVR and PAR. Over the Canadian shelf of the Beaufort Sea, CDOM is highly abundant (aCDOMmax (350) = 6.36 m-1) and strongly influenced by allochthonous inputs from the Mackenzie (peaks A-C and M) decreasing conservatively with salinity. In marine waters (salinity> 25), CDOM had lower concentrations (aCDOM(350) = 0.21 ± 0.13 m-1) and originated from a recent in situ biological production favored by upwelling and brine injections (peaks B-T and M). Surprisingly, the main source of the marine humic-like component (peak M) was not autochthonous. This material originates from allochthonous inputs from the Mackenzie River, which traverses numerous lakes where intense biological activity occurs. We suggest that this activity is mainly due to the macrophytes development, which may in part explain the origin of the peak M. This source of organic allochthonous CDOM coupled to other processes such as photobleaching and absorption on the particles of terrestrial CDOM, could explain the high values of SCDOM (≈ 0.020 nm-1) recorded in the Mackenzie during summertime
Ståhl, Henrik. "Carbon-cycling in deep-sea and contrasting continental margin sediments /." Göteborg : Göteborg university, 2001. http://catalogue.bnf.fr/ark:/12148/cb401108738.
Lescure, Chantal. "Relation bassin versant-étang : étude quantitative de l'azote inorganique dans les échanges atmosphère-sol-eau." Lyon 1, 1987. http://www.theses.fr/1987LYO11740.
Boulard, Eglantine. "Stabilité de phases carbonatées en conditions mantelliques : implications pour le cycle géodynamique du carbone." Phd thesis, Institut de physique du globe de paris - IPGP, 2011. http://tel.archives-ouvertes.fr/tel-00669781.
Loukos, Harilaos. "Simulation du cycle oceanique du carbone dans l'atlantique equatorial. Validation de l'annee 1983 (focal)." Paris 6, 1995. http://www.theses.fr/1995PA066148.
Bergeot, Vincent. "Polymérisation par ouverture de cycle de l'ε-caprolactone dans le dioxyde de carbone supercritique". Bordeaux 1, 2002. http://www.theses.fr/2002BOR12584.
Lambert, Thibault. "Sources, production et transfert du carbone organique dissous dans les bassins versants élémentaires sur socle : apports des isotopes stables du carbone." Phd thesis, Université Rennes 1, 2013. http://tel.archives-ouvertes.fr/tel-00857422.
Martin, Olivier Valérie. "Etude par cytometrie en flux de la distribution des populations phytoplanctoniques en mediterranee. Mise en relation avec la production metabolique de co 2 et comparaison avec le golfe du saint-laurent." Aix-Marseille 2, 1997. http://www.theses.fr/1997AIX22130.
Crichton, Katherine. "The role of permafrost soils in the global carbon-cycle on the timescales of centuries to multi-millennia : a modelling study." Thesis, Grenoble, 2014. http://www.theses.fr/2014GRENU049/document.
This study aimed to develop a permafrost-carbon dynamic model to incorporate into the CLIMBER-2 Earth system model and to carry out simulations with a view to contributing to the knowledge of the carbon cycle. The work would, for the first time, allow a fully coupled modelling study with an earth system model which included dynamic atmosphere, ocean, vegetation and cryosphere components including frozen land to study paleoclimates. The availability of recent ice core data for CO2 and δ13C of atmospheric CO2 was to provide a means of validating model findings to identify whether a permafrost-carbon dynamic could have played a significant role in past changing climates.The deep Southern Ocean is an area of particular interest for glacial-interglacial CO2 variability, and current modelling efforts aim to recreate the observed CO2 changes using ocean mechanisms. These are often related to deep southern ocean carbon storage and release. So far the terrestrial biosphere has not been well-considered in transient simulations of the carbon cycle in Earth system models.A simplified permafrost-carbon mechanism was developed and validated and tuned using data from termination 1. It was found that in order to reproduce atmospheric CO2 and δ13C data (for atmosphere and ocean) during the termination, a combination of glacial ocean mechanisms and the permafrost-carbon mechanism was required. Following this finding, several glacial cycles were modelled to study the sensitivity of the permafrost-carbon mechanisms to CO2, ice sheets and insolation. Ice sheet extent was found to be particularly important in controlling the land area available for permafrost and therefore the carbon dynamics of permafrost-carbon. The permafrost-carbon mechanism, via carbon release from thawing soils responding to increasing summer insolation in higher northern latitudes, was found to very likely be the source of initial rises in CO2 on glacial terminations.Termination 1 CO2 data could be well reproduced, including the B-A/YD CO2 plateau, when fresh water forcing was applied to the north Atlantic. Fresh water forcing experiments pointed to the importance of the permafrost-carbon mechanism in fast changing climates. Very fast increases in atmospheric CO2 levels may be explained by fast soil-carbon release responding to increased heat transport to the northern hemisphere on AMOC resumption following an AMOC switch-off/reduction event, such as D/O events seen in the Greenland δ18O record. Future climate change projections represent fast warming events. Driving the model by emissions projections (RCP database) predicted increased peak CO2 and much longer term elevated CO2 levels relative to model outputs which did not include the permafrost carbon feedback.Analysis of ocean δ13C must take into account the dynamics of permafrost and land carbon in general and its effect on atmospheric δ13C levels. If this is not taken into account then ocean circulation may be over-invoked in attempting to explain changes in ocean δ13C and atmospheric CO2. The Earth system is not simply atmosphere and ocean. The findings in this work highlight that it is essential to consider land carbon dynamics when interpreting paleo-indicators for the carbon cycle.The permafrost-carbon mechanism reacts to temperature changes and amplifies the carbon cycle's response. It is stongly dependent not only on energy input (that determines soil temperature and permafrost location), but also on the area of land available globally on which it can exist. In order to properly model and understand the Earth system response to forcing in both future and past climates, the permafrost-carbon feedback mechanism is an important system component. This work has been a first step to address the role that the land cryosphere plays in the carbon cycle and climate system on long timescales, and further studies are essential