Les anhydrases carboniques (AC) sont des enzymes qui catalysent les réactions d'hydratation du CO2 et d'hydrolyse de l’OCS. L’AC présente dans les plantes et les microorganismes du sol influence le bilan atmosphérique d'OCS ainsi que celui du CO18O car les isotopes de l’oxygène sont échangés avec ceux des pools d'eau pendant l'hydratation duCO2. L’utilisation de l’OCS et du CO18O comme traceurs du cycle du C global ouvre une nouvelle voie pour estimer les contributions de la photosynthèse et de la respiration à grande échelle. Ceci requiert néanmoins une meilleure compréhension des facteurs contrôlant l'activité de l’AC des sols. Nous avons étudié le rôle du pH du sol et des communautés microbiennes sur l'activité de l’AC. Nous avons testé l’hypothèse que l'activité de l’AC serait (H1) inhibée dans les sols acides, et que (H2) les échanges isotopiques CO2-H2O seraient réduits dans les sols alcalins. Nous avons également présumé que l'activité de l’AC serait (H3) positivement corrélée à l'abondance des microorganismes phototrophes, et que (H4) la structure des communautés affecterait différemment les flux de CO18O et d’OCS. Nos résultats valident H1 et H2. Ils montrent aussi que les flux de CO2 dans le sol et l'activité d’AC associée sont positivement corrélés à l'abondance des microorganismes phototrophes (H3), tandis que le dépôt d'OCS dans les sols dépend de l'abondance des champignons (H4). Ces résultats sont en cours d’intégration dans un modèle de l'activité de l’AC des sols mondiaux, ce qui permettra une estimation robuste des flux globaux de photosynthèse et de respiration à partir de bilans atmosphériques de COS et CO18O. / Carbonic anhydrases (CA) are a group of enzymes that catalyse CO2 hydration and OCS hydrolysis. The presence of CA in plants and soil microorganisms is responsible for the largest atmosphere-biosphere exchange of OCS but also CO18O, because oxygen isotopes are exchanged with soil and plant water pools during CO2 hydration. Consequently, CO18O and OCS atmospheric mixing ratios have been proposed as complementary tracers of the global C cycle that could open avenues to estimate the contribution of photosynthesis and respiration at global scales. However, a mechanistic understanding of the drivers of CA activity is required. We investigated the role of soil pH and microbial community on soil CA activity. We hypothesised that CA activity should be(H1) inhibited in acidic soils but that (H2) the associated CO2-H2O exchange would also be reduced in alkaline soils. We further assumed that (H3) soil CA activity would be enhanced by an increase in soil phototrophs abundance, but that (H4) soil community structure would affect differently CO18O and OCS fluxes. Our results confirmed H1 and H2. We also confirmed that soil CO2 fluxes and the associated CA activity were positively correlated with phototrophic communities abundance (H3), while soil OCS uptake and the associated CA activity seemed driven by fungal abundance (H4). These findings are now being incorporated into a model of soil CA activity worldwide that will allow robust estimates of photosynthesis and respiration at large scales from the atmospheric budgets of OCS and CO18O.

This thesis is focused on attestation of ecotoxicity of octachlorstyrene (OCS), persistent organic pollutant (POP), by biological tests of toxicity. The toxicity of OCS was determined by using two kinds of alternative tests applied on fresh water organisms. First of them, Thamnotoxkit, is based on observation of mobility, immobilization or even killing of crustacean Thamnocephalus platyurus. The second one, Daphnotoxkit, applies crustacean Daphnia magna. For purposes of comparison, a standard test of toxicity – so called test of root growth inhibition of Sinapis alba and two fytotests – test of growth inhibition of Lemna minor and test of root growth inhibition of Allium cepa were performed as well.

Les activités anthropiques ainsi que des phénomènes naturels sont à l’origine de risques avérés pour l’environnement. L'Indonésie est un pays archipélagique qui contient de nombreuses îles et régions côtières, où la croissance exponentielle des activités anthropiques a exposé l’environnement indonésien à de graves détériorations au cours des dernières décennies. Cette étude vise à explorer (qualitativement et quantitativement) les niveaux de contamination des sédiment de surface et du biote (P. Viridis, P. erosa,) au travers de deux sites atelier : la baie de Jakarta et la lagune de Segara Anakan (Java, Indonésie).Les méthodes de préparation des échantillon (extraction par solvant puis purification par chromatographie d’adsorption) suivies de l’analyse des extraits par GC/MS/MS ont été développées et qualifiées (linéarité, spécificité, reproductibilité).Les n-alcanes, HAP, PCBs et OCs sont détectés à des teneurs pouvant atteindre respectivement 1935 µg/kgPS, 916 µg/kg PS, 116,49 µg/kg PS, et 16,70 µg/kg PS, dans des sediments et 1739 µg/kg PS des HAPs et 24,79 µg/kg PS des OCs dans le biote. Les hydrocarbures, comme les HAPs sont majoritairement d’origine pétrolière (fuites, transport utilisation) même si la contribution pyrolytique est toujours présente.L’évaluation du risque environnemental a été réalisés pour les HAP, PCBS et et les OCs en utilisant les lignes directrices de la qualité des sédiments (RQS). Ces données peuvent servir de référence de base dans le cadre du programme de gestion intégrée des bassins versants impliquant la biodiversité, l'écologie de l'eau douce, et l'activité économique dans le domaine de cette étude. / Environmental problems can increase due to anthropogenic activities or natural phenomena. Indonesia is an archipelagic country that consists of many islands and coastal regions, where the growth of anthrophogenic and natural activities has exhibited severe environmental degradation in the past few decades. This study aims to explore (both qualitatively and quantitatively) the extent and sources of organic contaminants, i.e., n-alkanes in surface sediments; PAHs, PCBs and OCs in sediments and mussels, P. viridis from Jakarta Bay, North Jakarta, and P. erosa from the Segara Anakan Lagoon. Each protocol was continued with qualitative and quantitative analysis by GC-QQQ(triple-quadropole)/MS. Matrix interferences have been evaluated with proper samples with suitable yield of extraction and analysis. The n-alkanes, PAHs, PCBs and Organochlorin pesticides are detected in the highest levels in sediments, respectively 1935 µg/kg dw, 916 µg/kg dw, 116,49 µg/kg dw, and 16,70 µg/kg dw. In addition, the highest levels of PAHs (1739 µg/kg dw) and OCs levels (24,79 µg/kg dw) were found in biota. The source of hydrocarbons source, such the PAHs were generalelly petroleum source (transport utilization) although the pyrolytic are still present in sediments and biota. Environmental risk assessment from sediment quality guidelines (SQGs) were used to evaluate the probability risk in marine environments. Besides SQGs, sediments and mussels also in regard to the extent of the PAHs, PCBs and OCs (i.e. pp’-DDE) have been compared to other studies conducted at some polluted sites.

La question principale de notre travail de recherche est: A quel type d'organisation internationale appartient l'OCS et quels sont ses buts d'existence ? Pourquoi les pays-membres coopèrent-ils au sein de l'Organisation ? Pourquoi coopèrent-ils dans des domaines dont ils ont établi les règles de coopération et sur quelles questions spécifiques ont-ils choisi de répondre ? Quels sont ses règles et les mécanismes de prise de décision, et quels sont sa structure organisationnelle et son mode de fonctionnement ? La deuxième question est : quelles sont ses raisons d'existence, ses buts et ses objectifs? Et la troisième interrogation est quelles sont ses promesses (potentiels) et ses limites ? En se basant sur la « théorie » des organisations internationales, à quel type d'organisation internationale l'OCS peut-elle appartenir ? Une Organisation de coopération ou d'intégration ? On peut se demander quels sont les véritables objectifs d'une telle organisation. Est-ce que l'OCS a pour but de contrebalancer l'Occident ou y a-t-il d'autres raisons à son existence ? Quelles sont ces raisons ? Pour répondre à ces interrogations, deux hypothèses doivent être mises en évidence. Dans la première hypothèse, l'OCS est une organisation de coopération régionale comme beaucoup d'autres organisations régionales déjà existantes (OTAN, OTSC, CEI, etc.) Dans la deuxième hypothèse, l'OCS est une organisation néo-réaliste ou même néo-libérale étant donné que de simple coopération elle se transforme en une organisation d'intégration régionale, qui conduit à l'apparition d'une nouvelle région unique (unifiée) et qui se dirige vers le régionalisme. / The main question of our research is what kind of international organization is the SCO and what are its reasons for existence? In terms of the theory of international organizations to which type of international organization, the SCO can belong? The Organization of cooperation or integration? One wonders what the real objectives of the organization. Is the SCO aims to counteract the West, or there are other reasons for its existence? What are those reasons? Is it destined to exercise a single regional role in the manner of existing organizations such as CSTO, ECO, CIS, etc..., or does it move into the ranks of a world power? Are the objectives of the existence of this structure is to serve the great powers like Russia and China or it is also to serve to the small countries of Central Asia? Do the member countries have common objectives or individual, selfish? Is the SCO is an instrument of countries to achieve their national interests or they have a common desire to unite and grow together, to be a force in an "unfair" world?To answer these questions, two assumptions should be highlighted.For the first case, the SCO is a regional cooperation organization like many other existing regional organizations (NATO, CSTO, CIS, etc.). The SCO is an instrument of foreign policy of member countries to achieve its objectives joint problem solving as: regional security, economic development and cooperation policyIn the latter case, the SCO is transformed from mere cooperation in the organization of regional integration, which leads to the emergence of a new region (unified) - which moves towards regionalism. To these questions our dissertation is dedicated.

An algorithm for extracting event information from a Coulomb Explosion Imaging (CEI) position sensitive detector (PSD) is developed and compared with previously employed schemes. The PSD is calibrated using a newly designed grid overlay and validates the quality of the described algorithm. Precision calculations are performed to determine how best the CEI apparatus at The University of Waterloo can be improved. An algorithm for optimizing coincidence measurements of polyatomic molecules in CEI experiments is developed. Predictions of improved efficiency based on this algorithm are performed and compared with experiments using a triatomic molecule. Analysis of an OCS targeted CEI experiment using highly charged Argon ions to initiate ionization is performed. The resulting measurements are presented using a variety of visualization tools to reveal asynchronous and sequential fragmentation channels of OCS3+.

An algorithm for extracting event information from a Coulomb Explosion Imaging (CEI) position sensitive detector (PSD) is developed and compared with previously employed schemes. The PSD is calibrated using a newly designed grid overlay and validates the quality of the described algorithm. Precision calculations are performed to determine how best the CEI apparatus at The University of Waterloo can be improved. An algorithm for optimizing coincidence measurements of polyatomic molecules in CEI experiments is developed. Predictions of improved efficiency based on this algorithm are performed and compared with experiments using a triatomic molecule. Analysis of an OCS targeted CEI experiment using highly charged Argon ions to initiate ionization is performed. The resulting measurements are presented using a variety of visualization tools to reveal asynchronous and sequential fragmentation channels of OCS3+.

Barrier island restoration and nourishment is necessary for sustaining coastal systems worldwide. In the Mississippi River Delta Plain, the lack of sediment supply, relative sea level rise, and reworking of abandoned delta lobes promote rapid disintegration of barriers, which can contribute to mainland storm impacts. Barrier island restorations that utilize higher quality sediments (Outer Continental Shelf- OCS) are expected to exhibit higher resiliency, withstanding coastal erosion, event-induced erosion, and ongoing transgression when compared to barriers nourished using lower quality nearshore (NS) sands. Additionally, use of OCS sediments increases sediment supply by adding material to the system supporting increased barrier longevity by maintaining a subaerial footprint longer compared to NS sediments. We used the Delft3D modeling suite to study barrier geomorphic trajectories nourished using OCS/NS sands, compared with control simulations with no nourishment. Resulting morphologies from 18 simulations with forcing that included annualized forcing, storms, and SLR are evaluated and compared.

L'explosion démographique a conduit à une augmentation intensive des contaminants environnementaux issus de différentes émissions anthropiques, par exemple, les hydrocarbures de pétrole, les pesticides, les biphényles polychlorés (BPC) ainsi que d’autres déchets ménagers tels que les détergents utilisés comme nettoyants ménagers. Du fait de leur persistance et du point de vue toxicologique, les résidus de ces contaminants organiques, qui peuvent être détectés dans les différentes matrices environnementales (eau, sédiments, air et biotes), parfois à très faible concentration (micropolluants), ont conquis l'attention du public. Cette étude vise à déterminer les niveaux de concentration de contaminants sélectionnés dans les sédiments de surface et à identifier la source de ces produits chimiques dans le ruisseau Cortiou. Les résultats ont montré une forte contamination par les hydrocarbures dans la zone étudiée. De plus, ces résultats ont probablement reflété le fait que les processus de biodégradation se sont produits parallèlement à une répartition chronique des charges d’épuration non traitées. Ces polluants organiques ont également confirmé un effet néfaste sur le biote marin et plus particulièrement sur les communautés benthiques pour certaines stations / Demographic explosion has led to increase intensively environmental contaminants issued from different anthropogenic release e.g. petroleum hydrocarbons, pesticides, polychlorinated biphenyls (PCBs) and also other domestic waste such as detergents as household cleaner. Due to their persistence and the toxicological point of view, the remnants of these organic contaminants, which can be detected in the different environmental matrices (water, sediment, air and biota), sometimes with very low concentration (micropollutants), has gained the public attention. This study aims to determine the concentration levels of selected contaminants in surficial sediments and identifying the source of these chemicals in Cortiou Creek. The results showed high contamination by hydrocarbons in the studied area. Additionally, these results probably reflected that biodegradation processes occurred concomitantly with a chronic apportionment of untreated sewage loading. These organic pollutants also confirmed an adverse effect for marine biota and more particularly for benthic communities for some stations

Persistent organic pollutants (POPs) are hydrophobic substances that readily sorb to organic matter in particles and colloids instead of being freely dissolved in the water phase. This sorption affects the bio­availability and environmental transport of the POPs. The major part of this thesis concerns the role of sediments as secondary sources of POPs. As the primary emissions decrease, contaminated sediments where POPs have accumulated can become the main source of contamination. If the contaminated sediment by time becomes covered with cleaner layers, the POPs are buried and no longer in contact with the aquatic environment. Experiments in this thesis showed, however, that new invading species can alter the sediment-water dynamics as a result of their bioturbation, i.e. mixing of sediment particles and pore-water. Marenzelleria spp., invading species in the Baltic Sea that burrow deeper than native species, were found to increase the remobilization of buried contaminants. The sediment-to-water flux was inversely related to the burial depth (2-10 cm) of the POP congeners (polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers) and also inversely related to the hydrophobicity of the congener. The flux was therefore most pronounced for less hydrophobic contaminants, which was linked to the bioirrigating behaviour of these species. Marenzelleria spp. also accumulated the buried POPs and increased concentrations in surface sedi­ment. Contaminants previously considered buried at a ’safe’ depth can thus be remobilized as a result of the invasion of Marenzelleria spp. in the Baltic Sea. One method to decrease the remobilization of contaminants from sediments is ’capping’, i.e. a layer of clean material is placed as a cap on the sediment. By amending the cap with active materials, which sequester the POPs and decrease their availability, thinner layers can be used (’active capping’ or ’thin-layer capping’). Results from an experiment with thin-layer capping using different active materials (activated carbon (AC) and kraft lignin) showed that both the sediment-to-water flux and the bioaccumulation by benthic species of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs), hexachlorobenzene (HCB) and octachlorostyrene (OCS) decreased with increased thick­ness of the cap layer (0.5-5 cm). Amendments with active materials further increased the cap efficiency. AC was more efficient than kraft lignin, and a 3 cm cap with 3.3% AC reduced the flux and bioaccumulation with ~90%. The reduction of the sediment-to-water flux was inversely related to the hydrophobicity of the POP, and reductions in the flux had similar magnitudes as reductions in the concentration in deep-burrowing polychaetes, demonstrating the importance of bioturbation for sediment-to-water transport. In a one-year study on the levels of PCDD/Fs, PCBs, and HCB in a coastal area of the Baltic Sea, the correlations between the POP levels and the levels of particles and organic carbon in the water were found to differ for POPs of different structure and hydrophobicity. The levels of PCDD/Fs decreased to one third in May, which could be related to the increased sedimentation, i.e. water-to-sediment transport, during spring bloom.