This thesis documents the work undertaken to investigate and improve the theoretical and practical requirements for two-dimensional hydrodynamic modelling of coastal and estuarine areas, in particular to the inter-related aspects of: - wetting and drying of relatively large intertidal areas, and - the influences of waves on both current generation and variations in mean water level. The work outlined in this thesis began as a result of a perceived lack of understanding and confidence in the application of finite element models to coastal and estuarine situations. In response to this observation an investigation into the modelling parameters, particularly those that affect model performance during the simulation of wetting and drying, was undertaken. This initial investigation into the effect of these parameters upon model performance forms the first component of this study. Testing was performed to provide a quantitative assessment of the effect of these parameters upon model performance. The initial tests were simple examples designed to investigate the behaviour of a single specific parameter. Subsequent tests were more complex and assessed the combinations of various parameter selections. Once the model was shown to accurately simulate the movement of waters in a coastal and estuarine environment, wave forces were incorporated. The aim of the second component of the study was to modify the hydrodynamic model to predict the net current and water levels attributable to the influences of waves. Tests examined the effects of the application of wave induced forces in a range of applications, including the simple case of a uniform beach, comparisons to a physical model, and an example from a real coastline. The final outcome of this study is the development of a modelling tool that can accurately represent the forces of tides, winds and waves upon water movement in a shallow coastal and/or estuarine region. Furthermore, the qualitative and quantitative assessments of parameters that affect the performance of the model provide greater confidence in model results and better understanding of the applicability and limits of the modelling technique. Principal outcomes of the study are: - an improved understanding of the parameters which influence the behaviour of hydrodynamic models; - a better understanding of the applicability and limits of the modelling technique; and - an enhanced software system based on an existing modelling software system which is applicable to studies that require simulation of the combined forces of tides, winds and waves.

Diss. (sammanfattning) Uppsala : Sveriges lantbruksuniversitet, 2008. / Härtill 6 uppsatser.

The development of offshore wind farms and marine renewable energy devices in the Mediterranean is central to both national, and international, energy strategies for countries bordering the Mediterranean Sea. The ecological impacts of marine renewable energy development in the Mediterranean region, although essential for policy makers, are as yet unknown. The Northern Adriatic is identified as a plausible site for offshore wind farm development. Using the wider region (Adriatic and Northern Ionian) as a case study, this thesis examines the likely impact to the marine environment if an offshore wind farm is established. Site suitability, based on wind speed, bathymetry, and larvae connectivity levels are investigated along with the plausibility of the turbines operating as artificial reefs in the area. As offshore wind farms may alter the larval connectivity and supply dynamics of benthic populations, a connectivity map was constructed to identify areas of high and low connectivity in the Adriatic Sea. The Puglia coast of Italy is a likely larval sink, and displays some of the highest connectivity within the region, suggesting potential inputs of genetic materials from surrounding populations. Considering offshore wind farms could operate as artificial reefs, an in-situ pilot project was established to simulate the presence of wind turbines. Macroinvertebrates colonized the new substrata within the first few months but were lower in abundance when compared to a natural hard substrata environment. Time, turbine location, and the material used for turbine construction all affected the macro-invertebrate communities. In addition, fish abundances, and diversity were lower around the simulated OWF foundations in comparison to a natural hard substrata environment, and no increases in fish abundance occurred around the simulated turbines when compared to reference sites of soft substrata. This observation was validated with the use of an ecosystem modelling software (Ecopath with Ecosim), which simulated the overall ecosystem level impacts that would occur if 50 offshore monopile wind turbines were introduced to the Northern Ionian and colonized by macroinvertebrate communities. When compared to the baseline scenario (no simulated introduction of an OWF), the introduction of new habitat had no discernible impacts to the structure or functioning of the marine ecosystem. Noticeable changes to the ecosystem were only apparent if fishing restrictions were enforced in parallel with the simulated offshore wind farm; the ecosystem appears to become more structured by top down predation. In addition seabirds are also impacted by the reduction of fishing discards as a food source. These results are the first attempt to quantify the suspected benefits of offshore wind farms operating as de-facto marine protected areas.

Dissertação(mestrado) - Universidade Federal do Rio Grande, Programa de Pós-Graduação em Engenharia Oceânica, Escola de Engenharia, 2011. / Submitted by Lilian M. Silva (lilianmadeirasilva@hotmail.com) on 2013-04-20T20:11:55Z No. of bitstreams: 1 Estudo de fibras de aço em blocos de concreto para a possível utilização em carapaça de molhes.pdf: 6421003 bytes, checksum: 60c7e55066658c2ba4d808a487cc9c33 (MD5) / Approved for entry into archive by Bruna Vieira(bruninha_vieira@ibest.com.br) on 2013-06-04T17:05:53Z (GMT) No. of bitstreams: 1 Estudo de fibras de aço em blocos de concreto para a possível utilização em carapaça de molhes.pdf: 6421003 bytes, checksum: 60c7e55066658c2ba4d808a487cc9c33 (MD5) / Made available in DSpace on 2013-06-04T17:05:53Z (GMT). No. of bitstreams: 1 Estudo de fibras de aço em blocos de concreto para a possível utilização em carapaça de molhes.pdf: 6421003 bytes, checksum: 60c7e55066658c2ba4d808a487cc9c33 (MD5) Previous issue date: 2011 / Este trabalho tem como propósito de estudo o possível uso da utilização das fibras de aço em blocos de contenção às ondas marinhas, de modo a influenciar a resistência e durabilidade dos mesmos. Foram analisados em exame visual, os tetrápodes do molhe leste da Barra do Cassino (Rio Grande – RS), nos quais, pode-se verificar sua deterioração através de quebras e desgastes nos recentes 10 anos seguidos após sua instalação. De modo a diminuir custos com reposições, serviços com mão-de-obra e influenciar na durabilidade dos blocos, buscando um aumento da ductibilidade e uma melhora quanto a ações dinâmicas, a adição de fibras de aço no concreto pode ser uma alternativa vantajosa. Para isso, foram estudados três diferentes teores de fibras além do concreto base(referência) com o intuito de verificar as resistências obtidas. Paralelamente aos ensaios de resistência, foram desenvolvidos ao longo dos 24 meses de curso, ensaios de durabilidade com blocos de concreto expostos às intempéries do ambiente marítimo, como também ensaio de imersão e secagem a blocos em solução contendo íons cloreto. Foram realizados ensaios de compressão axial, resistência à tração por compressão diametral e ensaios de resistência à tração na flexão em corpos de prova cilíndricos e prismáticos de forma analisar o comportamento da resistência de influência das fibras a estes blocos. Com o intento de verificar a energia necessária para fissurar e gerar o colapso em corpos de prova cilíndricos (10 x 80 cm) – estes reforçados por diferentes teores de fibras, ou não – foi desenvolvido um equipamento que simulasse o impacto recebido no cilindro pela batida constante de uma esfera, simulando a batida de um tetrápode contra outro provocada pela ação das ondas. O teor que apresentou melhor desempenho das propriedades mecânicas foi o traço de 90 kg/m³, devido a este ser o mais próximo do volume crítico do concreto analisado, pois com esse teor os ganhos de resistência são significativos quando comparados aos traços com teores menores. / This paper aims to study the possible use of steel fibers in blocks of contention to sea waves, in order to influence at their strength and durability. It was analyzed by visual examination, the tetra pod of the east breakwater of Cassino beach (Rio Grande – RS), in which their deterioration through wear and breaks in the recent 10 consecutive years after its installation were verified. Conductive to reduce replacement costs, services with manpower and influence in the durability of the blocks, seeking an increase in ductility and an improvement in the dynamic action, the addition of fibers of steel in concrete can be an attractive alternative. Aiming that, it was studied three different fiber content besides the base of concrete (reference) targeting an economic viability related to the obtained resistances. Alongside the resistance tests, it has been developed over the 24 months of the course, with durability testing on concrete blocks exposed to the elements of the maritime environment, as well as testing of immersion and drying of blocks in a solution containing chloride ions. In contemplation of this, it was performed axial compression tests, tensile strength by diametrical compression tests and tensile strength in bending specimens used in prismatic and cylindrical specimens in order to analyze the behavior of the strength of influence of the fibers to these blocks. Aiming to verify the energy needed to crack and generate the collapse on the body of cylindrical specimens (10 x 80 cm)- reinforced by different levels of fiber, or not – it was developed a device which simulates the received impact on a cylinder by the steady beat of a sphere, simulating the tetra pods impacts against each other caused by the wave action. The content that has presented the best performance of the mechanical properties was the print of 90 kg/m³, due to the aspect that it is closer to the critical volume of concrete analysis, since with this level, the strength gains are significant when compared to traits with lower levels.

La lignée verte (i.e. les plantes) est représentée dans l'océan par les algues appartenant aux Chlorophyta. Celles-ci contribuent en moyenne à 25% des séquences photosynthétiques (Dinoflagellés exclus) retrouvées dans les inventaires moléculaires pan-océanique. Bien que les Chlorophyta jouent un rôle important dans l'écologie de l'océan et nous permettent de comprendre l'histoire évolutive des plantes terrestres, leur diversité et leur distribution dans les eaux marines du globe est peu documentée. Après avoir optimisé une base de données de séquences de références ARNr 18S, j'ai procédé à l'analyse de données de métabarcodes produits par Ocean Sampling Day (OSD), qui a fourni des données utilisant 2 régions hypervariables du gène du 18S appelées V4 et le V9. La comparaison des images de diversité produites par le V4 et le V9 a illustré l'influence de la base de référence sur la diversité. Ensuite, l'analyse de l'ensemble des V4 a permis d'étudier la distribution des Chlorophyta dans l'océan mondial. De plus, la vérification de l'assignation automatique des OTUs par reconstruction phylogénétique grâce à la base de référence produite en début de thèse, a permis de confirmer l'existence de nouvelles lignées de prasinophytes et de confirmer que la classe des Mamiellophyceae dominait les eaux côtières, alors que les clades VII et IX des prasinophytes dominaient les eaux océaniques oligotrophiques. Ces analyses ont aussi permis de montrer l'écart entre la diversité environnementale et celle dans la base de référence, en particulier pour les genres Ostreococcus et Micromonas (Mamiellophyceae). / The green lineage that dominates on land is represented by Chlorophyta which account in average for 25% of photosynthetic sequences (Dinoflagellates excluded) in global marine molecular inventories. Although Chlorophyta are major keys for ecological understanding of the ocean, as well as the evolutionary story understanding of land plants, their diversity and distribution in marine waters has been understudied. This thesis aims at investigating the environmental diversity of marine Chlorophyta and describing their distributions based on available large scale metabarcoding datasets. First, a reference database of publicly available 18S rRNA sequences of Chlorophyta was assembled and critically curated. Next, the Ocean Sampling Day (OSD) 18S metabarcode datasets were analysed. Chlorophyta diversity was compared for a limited sample set based on two regions of the 18S rRNA: the V4 and V9 regions. Then, Chlorophyta distribution was studied using the full OSD V4 dataset. Careful taxonomic investigations using both automatic and hand checked assignation of OTUs using alignments and phylogenies allowed to confirm the existence of new environmental prasinophytes clades and to confirme, that the Mamiellophyceae were the major group in coastal waters, while prasinophytes Clade VII and IX were dominating the oceanic oligotrophic stations. Comparing V4 and V9 regions illustrated the influence of the reference database on diversity. Moreover, the taxonomic investigation highlighted the diversity gaps between reference databases and environmental datasets. This work emphasizes the neglected importance of Chlorophyta in marine waters and provides some suggestions for future research.

This thesis studies the static and fatigue failure of carbon fibre-epoxy composite for marine use. The primary objective is to investigate the effects of sea water ingress on the static and cyclic performance of laminated composites, by using the combination of experimental, numerical and analytical approaches. Experiments were carried out to collect evidence, including data and images, for further analysis. Samples were made from autoclave-cured carbon fibre-epoxy pre-preg for the static, moisture diffusion and fatigue tests. Three chambers were used in the diffusion test, containing fresh water (tap water), sea water and sea water at 70 bar hydrostatic pressure respectively. And the chambers were placed in an oven at a constant temperature 50 °C in order to accelerate the water absorption. Optical and scanning electron microscopies (SEM) were employed to inspect for manufacturing defects and to identify the failure modes. Some formulae were derived to predict the material properties of laminated composites, to validate the mechanical tests, and to explain the failure criteria of composites. Finite element analysis (FEA) was employed to study the phenomena that were observed in the experiments. FEA has the aim to simulate the static, diffusion and fatigue behaviour involving multiphysics and multiscale effects. The FEA modelling has revealed details of the stress and moisture distributions, which have helped to understand the failure mechanisms of laminated composites. Classical laminate theory (CLT) was employed to develop an analytical model. The basic principles of CLT were extended to three-dimensions, and the analytical solution was critically compared with the FEA results. Some MATLAB tools based on CLT were developed to predict the properties of laminated composites and to analyse the experimental data. These MATLAB codes are shown in the appendix. This thesis has contributed to an improved knowledge of the failure mechanisms of composite materials in both normal and marine environments, and to optimize structural design of FRP composites.

Les substances pharmaceutiques et les produits de soin utilisés pour la protection de la santé humaine sont retrouvés dans tous les compartiments du milieu aquatique. Certaines de ces substances présentent des caractéristiques physico-chimiques ou pharmacologiques suggérant une capacité à se bioaccumuler comme les filtres UV EHMC et OC aux log Kow supérieurs à 5 ou les benzodiazépines diazépam et tétrazépam aux log de Kow de 2,82 et 3,20. L'objectif de ce travail de thèse a été d'évaluer la contamination des moules par 3 filtres UV et de 2 benzodiazépines. Pour cela, une méthode analytique a été mise au point et validée pour le dosage de ces substances dans les moules. Le dosage de l'EHMC et de l'OC a montré qu'en milieu côtier la contamination des moules in situ provient majoritairement des activités récréatives en période estivale et que cette contamination est augmentée dans des zones semi-fermées. Des expérimentations de bioaccumulation sur ces deux substances ont montré que les moules ne bioaccumulent pas ces filtres UV ; elles reflètent les niveaux de contamination en temps réel. Les niveaux de benzodiazépines dans les moules ne sont pas détectables en milieu côtier. Des expérimentations en conditions contrôlées ont montré que les moules absorbent les benzodiazépines. Cependant, elles les éliminent et probablement les métabolisent. L'utilisation de moules pour l'étude de la contamination par des substances émergentes permet l'identification de zones ou de périodes à risque élevé. / Pharmaceutical and personal care products used for human health protection are detected in all aquatic ecosystems. Among them, some compounds have physico-chemical or pharmacological properties that suggest a bioaccumulation capability. It’s the case of the UV filters, EHMC and OC, with log Kow higher than 5 or pharmaceuticals like diazepam and tetrazepam, with log Kow higher than 2.82. The aim of these Phd works was to assess marine mussels contamination for UV filters and benzodiazepines. So, a new analytical method was developed and validated for the determination of these compounds in mussels. EHMC and OC analysis realized in mussels sampled in French coastal waters showed that mainly contamination came from recreational activities in summer season, and that semi-closed areas were more contaminated. Moreover, laboratory experiments showed that mussels had clearly not bioaccumulate these 2 UV filters. Contamination levels in mussels are controlled by water concentrations. Conversely, benzodiazepines were not detected in coastal mussels. However, laboratory experiments showed an accumulation of benzodiazepines in mussels, suggesting elimination and metabolization means. Mussels are nevertheless usefull bioindicators of marine contamination by emerging compounds, allowing to characterize higher risk areas or periods.

Le devenir des radionucléides naturels et anthropogéniques dans l’environnement demeure une préoccupation majeure des sociétés modernes nucléarisées. Parmi les compartiments environnementaux possiblement impactés, l’hydrosphère est ubiquitaire et peut transporter des composés ou éléments sur de très longues distances. L’évènement récent de Fukushima a démontré que le milieu marin pouvait être également directement impacté ce qui amène à des questionnements tant scientifiques que sociétaux. De nombreuses études ont déjà montré que les radionucléides présents dans l’eau de mer peuvent être fortement accumulés par les organismes marins mais pour autant leur spéciation est inconnue. Or cette connaissance est essentielle afin de maîtriser les mécanismes de transfert entre l’hydrosphère et la biosphère et d'évaluer in fine l’impact global sur l’Homme. Dans ce travail, nous avons choisi de déterminer expérimentalement la spéciation de trois actinides dans l’eau de mer dopée : l’uranium(VI), le neptunium(V) et l’américium(III) (via l’analogue europium(III)) en couplant des calculs de spéciation avec les outils spectroscopiques dont la Spectroscopie Laser Résolue en Temps (SLRT) et la Spectroscopie d'Absorption des Rayons X (EXAFS). Puis nous avons étudié les processus d’accumulation sur l’éponge A. cavernicola, choisi ici car considérée comme un biomoniteur de pollution pour les métaux lourds. L’accumulation de l’europium(III), de l’américium(III) et de l’uranium(VI) dans A. cavernicola a donc été investiguée à l'échelle de traces et ultra traces. Pour l'europium, les techniques d'imagerie X et électronique ont permis de localiser l'élément accumulé et d'en préciser la spéciation. / The fate of natural and anthropogenic radionuclides in the environment remains a major concern in our modern nuclearized societies. Among the environmental compartments, the hydrosphere is ubiquitous and can transport compounds or elements over very long distances. The recent event of Fukushima demonstrated that the marine environment could be directly affected and this raises both scientific and societal questions. Moreover, some studies have already shown that radionuclides present in seawater can be strongly accumulated by marine organisms although their speciation is most of the time unknown. Yet this knowledge is essential to better understand the transfer mechanisms from the hydrosphere to the biosphere and to evaluate their global impact on humans. In this work, we chose to experimentally determine the speciation of three actinides in doped seawater: uranium(VI), neptunium(V) and americium(III) (and the chemical surrogate europium(III)) by coupling speciation modeling with spectroscopic tools among which Time-Resolved Laser-Induced Fluorescence (TRLIF) and X-ray Absorption Spectroscopy (XAS). Then, we have studied the accumulation process in the sponge A. cavernicola, chosen here because it is considered as a biomonitor of heavy metal pollution. The accumulation of europium(III), americium(III) and uranium(VI) in A. cavernicola were investigated at trace and ultra-trace levels. Besides, for europium, X-ray and electronic imaging permit to localize the accumulated element in the sponge and to specify its speciation.

Declining sea ice area in the Canadian Arctic has gained significant attention with respect to the prospect of increased shipping activities along the Northwest Passage and Arctic Bridge shipping routes. Temporal trend and correlation analysis was performed on sea ice area data for total, first-year ice (FYI), and multi-year ice (MYI), and observed shipping activity within the Vessel Traffic Reporting Arctic Canada Traffic Zone (NORDREG zone) from 1990 to 2012. Relationships between declines in sea ice area and Arctic maritime activity were investigated alongside linkages to warming surface air temperatures (SAT) and an increasing melt season length. Statistically significant increases in vessel traffic were observed on monthly and annual time-scales, coincident with declines in sea ice area. Despite increasing trends, only weak correlations between the variables were identified, suggesting that other non-environmental factors have likely contributed to the observed increase in Arctic shipping activity including tourism demand, community re-supply needs, and resource exploration trends. As a first step towards quantifying spatial variability in shipping patterns, a case study was conducted using 2010 observed shipping data to reconstruct historical shipping routes using a least cost path (LCP) approach. This approach was able to successfully reconstruct vessel tracks compared to an independent data source (Automatic Identification System) to an accuracy of 10.42 km ± 0.67 km over the entire study area. A 25 km gridded product across the entire Canadian Arctic domain was produced for 2010, with this approach now providing a basis to apply this method over the entire record (since 1990) in future studies to investigate long term spatial variability and change of shipping activity across the Canadian Arctic.

The marine environment is polluted by plastics of all forms and sizes. To reduce this serious pollution, it is important to identify its sources. This work focuses on the me-chanically induced breakdown of plastic into smaller fragments as a source of secondary microplastic, the time scale in which these microplastics are formed as well as the influ-ence of different environmental conditions like matrix conditions, collision potential or UV irradiation on the abrasion and fragmentation behaviour of plastic debris. Since a systematic investigation of parameter influence is not possible in the environ-ment, laboratory experiments were developed to simulate natural conditions such as drift on the beach or wave action in the (low tide) surf and swash zone. For this purpose, selected plastic objects (PET bottles, HDPE caps, PS cups and LDPE bags) were ex-posed to collision and/or friction forces under different conditions. Besides visual in-spection of the destruction procedure, a number of different methods was used to char-acterize the process, e.g., counting of visible fragments (larger than 350 μm), micro-scopic analysis of the surface structure (binocular, SEM) and highly resolved analysis of particle numbers in the size range below 350 μm. In order to extract microplastic parti-cles (<5 mm) from the matrix, extraction methods were developed that were adapted to the given sample properties (matrix volume). Furthermore, based on the particle num-bers, the power law model was applied to analyse the fragmentation process in the con-text of the observed particle size distributions. Plastic samples exhibited various signs of mechanical impairment in form of surface abrasion, cracks, tears, perforation, crumpling and finally fragmentation. The formation of fragments in different sizes (macro-, meso- and microplastics) was observed. The plastic objects were classified according to their degree of destruction to elucidate the effect of the different experimental conditions. Results show that fragmentation and abrasion depend on individual properties of the plastic objects such as thickness or shape and on the potential of weakening the plastic structure by mechanical forces (collisions) or chemical degradation (UV irradiation). Environmental conditions also influence the plastic damage; surface abrasion plays a major role on the beach; fragmentation will most likely happen in the surf- and in the swash zone. However, both processes occur simultaneously and interact with each oth-er. Formation of secondary microplastics was shown to be likely in the marine environ-ment; it must therefore be considered as an important process in the light of microplastic contamination.