Made available in DSpace on 2015-03-13T17:08:32Z (GMT). No. of bitstreams: 1 WernerFT.pdf: 4981794 bytes, checksum: 659d4c7e2270b32fa3929a5b6a5ab459 (MD5) Previous issue date: 2002-02-26 / This dissertation the results of a research developed in the area of S?o Bento do Norte and Cai?ara do Norte, northern coast of the State of Rio Grande do Norte, during the period of June of 2000 to August of 2001, in the ambit of the projects MAMBMAR? (CNPq/CTPETRO) and PROBRAL (CAPES/DAAD).The objective principal of this research was the characterization of the sedimentary dynamics of this coast, with base in data of coastal process (winds, currents, waves and tides), with topographical risings (beach profiles and dunes), satellite images and sedimentary analyses. The more specific objectives were accomplished the coastal monitoring of this coast, to verify the maintenance of an erosive tendency or progradacional after the groynes construction for contention of the erosion in the beach of Cai?ara do Norte, as well as to verify the influence of the features of bottom of the platform interns adjacent on the pole petroliferous of Guamar?. The executed monitoramento allowed to identify that the movement of the sediments, along the year, in that area, is cyclical, reaching the largest oscillations during the months of winter (deposition) and they will summer (erosion). The sedimentologic studies indicated a general tendency for sands quartzosas, with gravel presence, moderately to good selected, with asymmetry predominantly negative. In agreement with the parameter of Dean (1957), used in the identification of the state morfodin?mico of the beaches, monitored beaches, are basically reflectivas with tendency to middlemen, what frames that space of the coast norteriograndense, as a space strongly vulnerable to erosive processes. The studies developed in the platform, it interns of this area, allowed to visualize for the first time, in large scale, the distribution of the features of the submarine bottom to the batom?trico coat of 25 meters. Being pointed out the presence of a high one topographical submerged, with about 5 meters of height, 1 km of width and more than 24 meters of extension, located in the platform it interns in front of S?o Bento do Norte; coincident with the trend of the system of flaws of Carnaubais. This feature relay an important paper on the control of the sedimentary processes and oceanographic, as well as in the coastal evolution of this area of the RN state, and they affect the area of the pole petroliferous of Guamar? directly. These results contribute to a better knowledge of the processes in the area, and consequently as subsidies implantation of measures of coastal and environmental protection for the cities of S?o Bento do Norte and Cai?ara do Norte, as well as to understand how the geological-sedimentary processes and oceanographic, in this area, are influencing the characteristics geoambientais of the pole petroliferous of Guamar? / Esta disserta??o apresenta os resultados de uma pesquisa desenvolvida na regi?o de S?o Bento do Norte e Cai?ara do Norte, litoral setentrional do Estado do Rio Grande do Norte, durante o per?odo de Junho de 2000 a Agosto de 2001, no ?mbito dos projetos MAMBMAR? (CNPq/CTPETRO) e PROBRAL (CAPES/DAAD). O objetivo principal da pesquisa foi a caracteriza??o da din?mica sedimentar do litoral em quest?o, com base em dados relativos ? din?mica costeira (ventos, correntes, ondas e mar?s), levantamentos topogr?ficos (perfis de praia e dunas), imagens de sat?lite e an?lises sedimentol?gicas. Como objetivos espec?ficos foram realizados o monitoramento deste litoral, com o fim de verificar a manuten??o de uma tend?ncia erosiva ou progradacional ap?s a constru??o de gabi?es para conten??o da eros?o na praia de Cai?ara do Norte, bem como verificar a influ?ncia das fei??es de fundo da plataforma interna adjacente sobre o p?lo petrol?fero de Guamar?. O monitoramento executado permitiu identificar que a movimenta??o dos sedimentos, ao longo do ano, nessa regi?o, exibe um padr?o c?clico, atingindo as maiores oscila??es durante os meses de inverno (deposi??o) e ver?o (eros?o). Os estudos sedimentol?gicos indicaram uma tend?ncia geral para areias quartzosas, com presen?a de cascalho, moderadamente a bem selecionadas, com assimetria predominantemente negativa. De acordo com o par?metro de Dean (1957), as praias monitoradas s?o basicamente reflectivas com tend?ncia a intermedi?rias, o que enquadra esse trecho da costa norteriograndense como fortemente vulner?vel a processos erosivos. Os estudos desenvolvidos na plataforma interna desta regi?o permitiram visualizar pela primeira vez, em macroescala, a distribui??o das fei??es do fundo submarino at? a is?bata de 25 metros. Ressaltando-se a presen?a de um alto topogr?fico submerso, com cerca de 5 metros de altura, 1 km de largura e mais de 24 metros de extens?o, localizado na plataforma interna em frente a cidade de S?o Bento do Norte, coincidente com o trend do Sistema de Falhas de Carnaubais. Esta fei??o exerce um papel importante no controle dos processos sedimentares e oceanogr?ficos, bem como na evolu??o costeira desta regi?o do Estado do RN, que afetam diretamente a regi?o do p?lo petrol?fero de Guamar?. Estes resultados contribuem para um melhor conhecimento dos processos atuantes na regi?o e, conseq?entemente, fornece subs?dios para a implementa??o de medidas de prote??o costeira e ambiental para as cidades de S?o Bento do Norte e Cai?ara do Norte, bem como para o melhor entendimento de modo como os processos geol?gicos e oceanogr?ficos atuantes nesta ?rea, v?m influenciando nas caracter?sticas geoambientais do p?lo petrol?fero de Guamar?

<p> The Morrissey Formation of the Kootenay Group was mapped and sampled in three outcrops in southwestern Alberta and southeastern British Columbia; Burnt Ridge and Sparwood Ridge in British Columbia and Adanac Mine sight in Alberta. </p> <p> The lowest unit mapped was within the upper Fernie Formation (Passage beds) and consists of interbeds of sandstone and siltstone that were deposited as shallow water marine sediments. </p> <p> The Morrissey Formation conformably overlies the Fernie Formation and contains two members; the Weary Ridge Member and the Moose Mountain Member. The Weary Ridge Member consists of fine to medium grain, parallel and trough crossbedded sandstone, that was deposited as a delta-front-sand facies produced by coalescing of delta-sands from three to four delta complexes. The overlying Moose Mountain Member consists of high angle trough crossbedded, coarse grain, "salt and pepper" sandstone representing a distributary mouth bar environment. The Moose Mountain Member is unconventional in that the upper portion contains two units not seen in other sections. A marine trace fossil unit and a beach unit are both found within the upper portion of the member. These two units represent a transgression caused by channel switching and a regression and reworking of sediments into a beach respectively. </p> <p> Above the Morrissey Formation are the continental coals and fluvial systems of the Mist Mountain Formation. </p> <p> Petrographic studies on twenty five thin sections show two sedimentary sources for the Formation. The first source being chert rich Upper Paleozoic carbonates and the second source is Lower Paleozoic clastics that have previously been derived from a metamorphic complex of the Canadian Shield. The sandstones are cemented by quartz syntaxial overgrowths implying that there was a moderate degree of pressure solution, indicating a fairly high overburden pressure during diagenesis. </p> / Thesis / Bachelor of Science (BSc)

O presente estudo teve por objetivo avaliar a influência de esgotos domésticos e petroquímicos, dispostos por via de emissário submarino, nas composições físico-químicas e microbiológicas da coluna dágua e na geoquímica dos sedimentos, bem como investigar uma possível relação entre o meio e a composição química das carapaças do foraminífero Ammonia tepida. Para atingir tal objetivo foram coletadas 10 amostras de água e de sedimento superficial, no entorno dos emissários do Araçá e do Terminal Petrolífero Almirante Barroso (TEBAR), além de um ponto controle, no canal de São Sebastião, SP, em março e abril de 2007. Em cada amostra de água foram realizadas análises físico-químicas e microbiológicas. Nos sedimentos, foram realizadas análises granulométricas e geoquímicas (macronutrientes, elementos maiores e traços). Do sedimento, carapaças coradas (indivíduos vivos) e não coradas (mortos) de A. tepida foram triadas e analisadas em espectrômetros de energia dispersiva (MEV-EDS) e de emissão atômica (ICP-OES) para análise química dos elementostraços. Os resultados das análises físico-químicas e microbiológicas da água, indicaram que a coluna dágua não estava contaminada, no momento da amostragem, pois todos os valores obtidos estavam dentro dos limites exigidos pela resolução do CONAMA, nº 357/2005. Os resultados granulométricos mostraram que o sedimento é litoclástico e mais psamítico no Araçá, e mais pelítico, no TEBAR. Já os dados geoquímicos de carbono orgânico, nitrogênio, enxofre e fósforo revelaram que ambas as regiões são propícias ao enriquecimento desses elementos. A concentração de elementos-traço, na maioria dos pontos estudados, nas duas áreas, quando comparada aos valores guia de causaefeito, não foi considerada tóxica para a biota marinha. Contudo, foi observado enriquecimento significativo de cádmio, em certas áreas no Araçá, e de bário, no TEBAR. A concentração deste último elemento, provavelmente, está relacionada à água de produção do terminal. Os elementos-traço das carapaças de A. tepida coradas, em ambos os emissários, apresentaram maior número de correlações significativas com o sedimento, sugerindo que carapaças de foraminíferos mortos estão mais susceptíveis ao viés dos processos diagenéticos. No TEBAR, foram observadas correlações significativas positivas entre os teores de Co, Cr, Mn e Pb nos sedimentos e os elementos-traço das carapaças coradas. Já no Araçá, somente os teores de Cr correlacionaram-se positiva e significativamente aos teores encontrados nas carapaças coradas. Isto corrobora com a influência da composição do sedimento nas reações intracelulares dos foraminíferos, refletidas na construção do exoesqueleto. Diante do exposto, os resultados deste estudo trouxeram luz a novas questões que permitiram inferir que a auto-depuração da água do mar, em ambas as regiões, e a estação de tratamento de efluentes, no TEBAR, não se revelaram eficientes na diluição e/ou remoção do conteúdo de nutrientes, matéria orgânica e elementos maiores e traço. / The goal of this study was to evaluate the influence of domestic and petrochemical sewage, discharged through a submarine sewage outfall, on the physicochemical and microbiological composition of the water column and the geochemistry of sediments. As well as to investigate a possible relationship between the environment and the chemical composition of Ammonia tepida foraminifer\'s tests. The area where this study was focused on two sewage emissaries: Araçá and Almirante Barroso Petroliferous Terminal (TEBAR), both located in São Sebastião Channel, São Paulo, Brazil. To achieve this goal, 10 water and bottom sediments samples in in March and April of 2007 were collected form each outfall. A background sample also collected as a control. For each water sample physicochemical and microbiological analyses were carried out and, in the sediments, grainsize and geochemical (macronutrients, major and trace elements) were analyzed. Trace elements found in the tests of stained (live) and unstained (dead) Ammonia tepida were identified by scanning electron microscopy using energy dispersive spectroscopy (SEM-EDS) and by inductively coupled plasma optical emission spectrometry (ICP-OES). The analysis of the water samples showed that the water column was not contaminated. All the concentrations obtained were in accordance with the National Environmental Council (CONAMA) limits. Grain size analysis, demonstrated that the sediments are of terriginous origin, being mainly psamitic in Araçá and mainly pelitic in TEBAR. The geochemical data of organic Carbon, Nitrogen, Sulphur and Phosphorus revealed that both regions are susceptible to enrichment in these elements. In both areas, the concentration of trace elements, when compared to quality guideline values, was not considered toxic for marine life. However, significative enrichment in Cadmium in certain areas of Araçá and Barium in TEBAR. The latter is probably related to the terminal\'s water production. In both outfalls, it was observed a significant correlation between the trace elements in the live A. tepida\'s tests and the sediment, which suggests that the dead foraminifera are more susceptible to diagenical bias. In TEBAR the correlations observed were significative and positive among the elements Co, Cr, Mn and Pb present in the sediments and the trace elements of the stained tests. In the Araçá outfall, only the Cr levels correlate significative and positively with the levels found in the tinged tests. This shows that sediment composition influences the intracelular reactions in the forminifera, which reflected in the exoskeleton\'s building. Given the above, the results of this study brought up new questions that allowed to infer that sea water depuration at both outfalls, as well as at sewage treatment plant, in TEBAR was not sufficient to dilute and/or remove the nutrient content, the organic matter and major and trace elements of the sewage.

Pesquisa realizada para analisar o compósito de solo de decapagem (SD) considerado resíduos nas jazidas de minérios, em especial de calcário do município de Almirante Tamandaré, da Região Metropolitana de Curitiba neste trabalho, juntamente com o lodo e sedimentos de dragagem marinha do Porto de Antonina, no Estado do Paraná, e o uso cal virgem comum, como aglomerante pertencente à região de Almirante Tamandaré. Foram utilizados vários teores dos materiais para a determinação de 12 (doze) compósitos. Para o solo de decapagem os teores variaram entre 30% a 60%, para o material de dragagem os teores variaram entre 20% a 50% e o teor de aglomerante de cal virgem comum variou entre 15% a 30%. Foram moldadas idades de cura de 3 dias, 7, 14, 28, 60, 90, 180 e 365 dias. O aumento da resistência à compressão durante a cura foi proveniente das reações químicas das partículas sólidas das matérias-primas em ambiente alcalino gerando novas formações amorfas. Também foram analisados os materiais nos métodos de MEV com EDS, DRX e FRX, para a obtenção da composição química e formação estrutural dos novos compósitos. Todos os resultados da resistência à compressão uniaxial, com 28 dias de cura ao meio ambiente das 12 (doze) composições, obtiveram resultados médios de 7,7 MPa, atendendo satisfatoriamente a norma NBR 7170:1983 que determina a resistência à compressão igual ou acima de 4,0 MPa, destinada à produção de materiais de construção para alvenaria de vedação, sem fins estruturais. Comprovando o uso desses compósitos em materiais de construção civil, principalmente para os segmentos de blocos ou tijolos de vedações, sem fins estruturais, sem a necessidade de cozimento ou empreendimento de energia calorífica para a cura das peças, contribuindo para o meio ambiente e a sustentabilidade ambiental. / Research conducted to analyze the composite with pickling soil (SD), considered waste in mineral deposits, especially of limestone in the city of Almirante Tamandaré, the Metropolitan Region of Curitiba in this work, along with the sludge and marine dredging sediment from the Port of Antonina, State of Paraná, and use the common quicklime as binder belonging to the same region of Almirante Tamandaré. Various amounts of materials were used for the determination of twelve (12) composites. For the stripping soil content ranged from 30% and 60%, for the dredging material contents ranged from 20% and 50% and binder common quicklime content ranged from 15% to 30%. Were molded curing ages of 3 days, 7, 14, 28, 60, 90, 180 and 365 days. The increase in compressive strength during curing was derived from the chemical reactions of solid particles of raw materials in alkaline environment generating the new amorphous formations. Also the raw materials were analyzed in the SEM with EDS method, DRX and FRX, to obtain the chemical composition and formation structures of the new composite. All results of the uniaxial compressive strength, with 28 days of curing the environment of the twelve (12) compositions, obtained average results of 7.7 MPa, satisfactorily meeting the NBR 7170:1983 standard that determines the resistance to compression equal or above 4.0 MPa, for the production of building materials for sealing masonry without structural purposes. Proving the use of these composites in construction materials, especially for thread block or brick fences without structural purposes, without the need for cooking or heating energy project for the healing of parts, contributing to the environment and sustainability Environmental.

O presente estudo teve por objetivo avaliar a influência de esgotos domésticos e petroquímicos, dispostos por via de emissário submarino, nas composições físico-químicas e microbiológicas da coluna dágua e na geoquímica dos sedimentos, bem como investigar uma possível relação entre o meio e a composição química das carapaças do foraminífero Ammonia tepida. Para atingir tal objetivo foram coletadas 10 amostras de água e de sedimento superficial, no entorno dos emissários do Araçá e do Terminal Petrolífero Almirante Barroso (TEBAR), além de um ponto controle, no canal de São Sebastião, SP, em março e abril de 2007. Em cada amostra de água foram realizadas análises físico-químicas e microbiológicas. Nos sedimentos, foram realizadas análises granulométricas e geoquímicas (macronutrientes, elementos maiores e traços). Do sedimento, carapaças coradas (indivíduos vivos) e não coradas (mortos) de A. tepida foram triadas e analisadas em espectrômetros de energia dispersiva (MEV-EDS) e de emissão atômica (ICP-OES) para análise química dos elementostraços. Os resultados das análises físico-químicas e microbiológicas da água, indicaram que a coluna dágua não estava contaminada, no momento da amostragem, pois todos os valores obtidos estavam dentro dos limites exigidos pela resolução do CONAMA, nº 357/2005. Os resultados granulométricos mostraram que o sedimento é litoclástico e mais psamítico no Araçá, e mais pelítico, no TEBAR. Já os dados geoquímicos de carbono orgânico, nitrogênio, enxofre e fósforo revelaram que ambas as regiões são propícias ao enriquecimento desses elementos. A concentração de elementos-traço, na maioria dos pontos estudados, nas duas áreas, quando comparada aos valores guia de causaefeito, não foi considerada tóxica para a biota marinha. Contudo, foi observado enriquecimento significativo de cádmio, em certas áreas no Araçá, e de bário, no TEBAR. A concentração deste último elemento, provavelmente, está relacionada à água de produção do terminal. Os elementos-traço das carapaças de A. tepida coradas, em ambos os emissários, apresentaram maior número de correlações significativas com o sedimento, sugerindo que carapaças de foraminíferos mortos estão mais susceptíveis ao viés dos processos diagenéticos. No TEBAR, foram observadas correlações significativas positivas entre os teores de Co, Cr, Mn e Pb nos sedimentos e os elementos-traço das carapaças coradas. Já no Araçá, somente os teores de Cr correlacionaram-se positiva e significativamente aos teores encontrados nas carapaças coradas. Isto corrobora com a influência da composição do sedimento nas reações intracelulares dos foraminíferos, refletidas na construção do exoesqueleto. Diante do exposto, os resultados deste estudo trouxeram luz a novas questões que permitiram inferir que a auto-depuração da água do mar, em ambas as regiões, e a estação de tratamento de efluentes, no TEBAR, não se revelaram eficientes na diluição e/ou remoção do conteúdo de nutrientes, matéria orgânica e elementos maiores e traço. / The goal of this study was to evaluate the influence of domestic and petrochemical sewage, discharged through a submarine sewage outfall, on the physicochemical and microbiological composition of the water column and the geochemistry of sediments. As well as to investigate a possible relationship between the environment and the chemical composition of Ammonia tepida foraminifer\'s tests. The area where this study was focused on two sewage emissaries: Araçá and Almirante Barroso Petroliferous Terminal (TEBAR), both located in São Sebastião Channel, São Paulo, Brazil. To achieve this goal, 10 water and bottom sediments samples in in March and April of 2007 were collected form each outfall. A background sample also collected as a control. For each water sample physicochemical and microbiological analyses were carried out and, in the sediments, grainsize and geochemical (macronutrients, major and trace elements) were analyzed. Trace elements found in the tests of stained (live) and unstained (dead) Ammonia tepida were identified by scanning electron microscopy using energy dispersive spectroscopy (SEM-EDS) and by inductively coupled plasma optical emission spectrometry (ICP-OES). The analysis of the water samples showed that the water column was not contaminated. All the concentrations obtained were in accordance with the National Environmental Council (CONAMA) limits. Grain size analysis, demonstrated that the sediments are of terriginous origin, being mainly psamitic in Araçá and mainly pelitic in TEBAR. The geochemical data of organic Carbon, Nitrogen, Sulphur and Phosphorus revealed that both regions are susceptible to enrichment in these elements. In both areas, the concentration of trace elements, when compared to quality guideline values, was not considered toxic for marine life. However, significative enrichment in Cadmium in certain areas of Araçá and Barium in TEBAR. The latter is probably related to the terminal\'s water production. In both outfalls, it was observed a significant correlation between the trace elements in the live A. tepida\'s tests and the sediment, which suggests that the dead foraminifera are more susceptible to diagenical bias. In TEBAR the correlations observed were significative and positive among the elements Co, Cr, Mn and Pb present in the sediments and the trace elements of the stained tests. In the Araçá outfall, only the Cr levels correlate significative and positively with the levels found in the tinged tests. This shows that sediment composition influences the intracelular reactions in the forminifera, which reflected in the exoskeleton\'s building. Given the above, the results of this study brought up new questions that allowed to infer that sea water depuration at both outfalls, as well as at sewage treatment plant, in TEBAR was not sufficient to dilute and/or remove the nutrient content, the organic matter and major and trace elements of the sewage.

Detailed information about the oceanic environment is essential for many applications in the field of marine geology, marine biology, coastal engineering, and marine operations. Especially, knowledge of the properties of the sediment body is often required. Acoustic remote sensing techniques have become highly attractive for classifying the sea bottom and for mapping the sediment properties, due to their high coverage capabilities and low costs compared to common sampling methods. In the last decades, a number of different acoustic devices and related techniques for analyzing their signals have evolved. Each sensor has its specific application due to limitations in the frequency range and resolution. In practice, often a single acoustic tool is chosen based on the current application, supported by other non-acoustic data where required. However, different acoustic remote sensing techniques can supplement each other, as shown in this thesis. Even more, a combination of complementary approaches can contribute to the proper understanding of sound propagation, which is essential when using sound for environmental classification purposes. This includes the knowledge of the relation between acoustics and sediment properties, the focus of this thesis. Providing a detailed three dimensional picture of the sea bottom sediments that allows for gaining maximum insight into this relation is aimed at.<p><p><p>Chapters 4 and 5 are adapted from published work, with permission:<p>DOI:10.1121/1.3569718 (link: http://asadl.org/jasa/resource/1/jasman/v129/i5/p2878_s1) and<p>DOI:10.1109/JOE.2010.2066711 (link: http://ieeexplore.ieee.org/xpl/articleDetails.jsp?tp=&arnumber=5618582&queryText%3Dsiemes)<p>In reference to IEEE copyrighted material which is used with permission in this thesis, the IEEE does not endorse any of the Université libre de Bruxelles' products or services.<p> / Doctorat en Sciences de l'ingénieur / info:eu-repo/semantics/nonPublished

The spatio-temporal patterns in concentrations of selected metals within the sediment (Cd, Co, Cu, Fe, Pb, Ni and Zn) and water (Cd and Pb) of three permanently open estuaries (Kariega, Kowie, Great Fish) and six temporary open-closed estuaries (Mpekweni, East Kleinemonde, West Kleinemonde, Riet, Kasouga, Boknes) were investigated. The concentrations of metals were influenced by size composition and total organic content of the sediments. Enrichment factors (EFs), using Fe as a reference element, and baseline linear regression models for metals vs. Fe were calculated to assess the extent of metal enrichment in the sediments. The mean concentrations of metals in the sediments(mg·kg⁻¹) showed ranges of 0.28 – 2.31 for Cd, 1.26 – 6.24 Co, 0.69 – 6.93 for Cu, 2119 – 14912 for Fe, 2.29 –14.01 for Ni, 4.81 – 22.20 for Pb and 5.77 – 21.75 for Zn. Mean normalized enrichment factors ranged between 0.75 – 6.19 for Cd, 0.53 – 2.71 for Co, 0.22 – 0.84 for Cu, 0.30 – 1.87 for Ni, 0.99 – 3.17 for Pb and 0.14 – 0.98 for Zn. All nine estuaries had average enrichment factors of greater than 1 for Cd. In general there was no enrichment of Cu and Zn in the sediments of any of the estuaries included in this study (EFs < 1). The Kariega, East Kleinemonde, West Kleinemonde, Riet and Great Fish Estuaries showed some degree of enrichment for Co (1 < EF < 4), Ni (1 < EF < 2) and Pb (1 < EF < 4), while the Mpekweni, Kasouga, Boknes and Kowie Estuaries were unenriched with these metals (EF < 1). Enrichment factors for Cd, Co and Pb typically followed the development gradient along the estuaries, suggesting anthropogenic enrichment. The concentrations of Cd and Pb in the water of the nine estuaries were also determined. The average concentrations of Cd and Pb in the water (μg·ℓ⁻¹) ranged between 0.05 – 3.32 and 0.75 – 34.13 respectively. On average the concentrations of Cd and Pb in the water of all the estuaries were below the South African recommended water quality guidelines for coastal marine waters. Variations in metal concentrations associated with changes in hydrology (wet vs. dry season) were determined in the water and sediment of the Kariega, East Kleinemonde and Riet Estuaries. Cobalt, Pb and Ni enrichment in the Kariega Estuary sediment was significantly higher during the dry season, and the mean concentrations of Pb and Cd in the water column were 19-fold and 66-fold higher in the dry season. The elevated concentration of metals during the dry season could be related to accumulation of diffuse pollution from human activities within the catchment area. Conversely, inflow of fresh water into the estuary had the net effect of reducing the concentration and enrichment of these metals within the Kariega Estuary due to scouring and outflow of estuarine water and sediment into the marine environment. The temporal variations in metal concentrations and enrichment factors were less pronounced in the temporary open-closed estuaries than the permanently open Kariega Estuary. The observed trend can probably be related to the low anthropogenic impact within the catchment areas of these systems, and the relatively smaller size of the catchments. Significant spatial variations existed in metal enrichment in the sediment of both the East Kleinemonde and Riet estuaries, with the highest degrees of enrichment occurring in the sediments from the marine environment and lower reaches.

Marine sediments are a key component of the global carbon cycle and climate system. They host one of the largest carbon reservoirs on Earth, provide the only long-term sink for atmospheric CO2, recycle nutrients and represent the most important climate archive. Early diagenetic pro- cesses in marine sediments are thus central to our understanding of past, present and future biogeochemical cycling and climate. Because all early diagenetic processes can be directly or indirectly linked back to the degradation of organic matter (OM), advancing this understand- ing requires disentangling the different factors that control the fate of OM (sedimentation, degradation and burial) on different spatial and temporal scales. In general, the heterotrophic degradation of OM in marine sediments is controlled by the quantity and, in particular, by the ap- parent reactivity of OM that settles onto marine sediments. While the potential ((micro)biological, chemical and physical) controls on OM reactivity are increasingly well understood, their relative significance remains difficult to quantify. Traditionally, integrated data-model approaches are used to quantify apparent OM reactivity (i.e. OM degradation rate constants) at well-studied drill-sites. These approaches rely on Reaction-Transport Models (RTMs) that typically account for transport (advection, molecular diffusion, bioturbation, and bioirrigation) and reaction (pro- duction, consumption, equilibrium) processes, but vary in complexity. Apparent OM reactivity (i.e. the OM degradation rate constant) is generally considered as a free parameter that is used to fit observed depth-profiles, reaction rates or benthic-pelagic exchange fluxes. Currently, no quantitative framework exists to predict apparent OM reactivity in areas where comprehensive benthic data sets are not available.To evaluate the impact of this knowledge gap, the sensitivity of benthic biogeochemical reaction rates, as well as benthic-pelagic exchange fluxes to variations in apparent OM reactivity (i.e. reactive continuum model parameters a and ν) is explored by means of a complex, numerical diagenetic model for shelf, slope and deep sea depositional environments. Model results show that apparent OM reactivity exerts a dominant control on the magnitude of biogeochemical reaction rates and benthic-pelagic exchange fluxes across different environments. The lack of a general framework to quantify OM reactivity thus complicates the parametrization of regional and global scale diagenetic models and, thus, compromises our ability to quantify global benthic-pelagic coupling in general and OM degradation dynamics in particular.To make a first step towards an improved systematic and quantitative knowledge of OM reac- tivity, apparent OM reactivity (i.e. reactive continuum model parameters a and ν) is quantified by inverse modelling of organic carbon, sulfate (and methane) sediment profiles, as well as the location of the sulfate-methane transition zone using a complex, numerical diagenetic model for 14 individual sites across different depositional environments. Model results highlight again the dominant control of OM reactivity on biogeochemical reaction rates and benthic exchange fluxes. In addition, results show that, inversely determined ν-values fall within a narrow range (0.1 < ν < 0.2). In contrast, determined a-values span ten orders of magnitude (1 · 10−3 < a < 1·107) and are, thus, the main driver of the global variability in OM reactivity. Exploring these trends in their environmental context reveals that apparent OM reactivity is determined by a dynamic set of environmental controls rather than traditionally proposed single environmental controls (e.g. water depth, sedimentation rate, OM fluxes). However, the high computational demand associated with such a multi-species inverse model approach, as well as the limited availability of comprehensive pore water data, limits the number of apparent OM reactivity estimates. Therefore, while providing important primers for a quantification of OM reactivity on the global scale, inverse model results fall short of providing a predictive framework.To overcome the computational limitations and expand the inverse modelling of apparent OM reactivity to the global scale, the analytical model OMEN-SED is extended by integrating a nG- approximation of the reactive continuum model that is fully consistent with the general structure of OMEN-SED. The new version OMEN-SED-RCM thus provides the computational efficiency required for the inverse determination of apparent OM reactivity (i.e. reactive continuum model parameters a and ν) on the global scale. The abilities of the new model OMEN-SED-RCM in capturing observed local, as well as global patterns of diagenetic dynamics are rigorously tested by model-data, as well as model-model comparison.OMEN-SED-RCM is then used to inversely determine apparent OM reactivity by inverse modelling of 394 individual dissolved oxygen utilisation (DOU) rate measurements. DOU is commonly used as a proxy for OM reactivity, it is more widely available than comprehensive porewater data sets and global/regional benthic maps of dissolved oxygen utilisation rates (DOU) have been derived based on the growing DOU data set. Sensitivity test show that, while inverse modelling of DOU rates fails to provide a robust estimate of RCM parameter ν, it is a good indicator for RCM parameter a. Based on previous findings, parameter ν was thus assumed to be globally constant. Inversely determined a-values vary over order of magnitudes from a = 0.6 years in the South Polar region to a = 5.6 · 106 in the oligotrophic, central South Pacific. Despite a high intra- as well as interregional heterogeneity in apparent benthic OM reactivity, a number of clear regional patterns that broadly agree with previous observations emerge. High apparent OM reactivities are generally observed in regions dominated by marine OM sources and characterized by efficient sinking of OM and a limited degradation during sinking. In contrast, the lowest apparent OM reactivities are observed for regions characterized by low marine primary production rates, in combination with a great distance to the continental shelf and slope, as well as deep water columns. Yet, results also highlight the importance of lateral transport processes for apparent OM reactivity. In particular, deep sea sediments in the vicinity of dynamic continental margin environments or under the influence of strong ocean currents can receive comparably reactive OM inputs from more productive environments and, thus, reveal OM reactivities that are higher than traditionally expected. Finally, based on the observed strong link between apparent OM reactivity (i.e. RCM parameters a) and DOU rate, a transfer function that predicts the order of magnitude of RCM parameter a as a function of DOU is used to derive, to our knowledge, the first global map of apparent OM reactivity.Finally, we use the new global map of apparent OM reactivity to quantify biogeochemical dynamics and benthic-pelagic coupling across 22 benthic provinces that cover the entire global ocean. To this end, the numerical diagenetic model BRNS model is set-up for each province and forced with regionally averaged boundary conditions derived from global data sets, as well as apparent OM reactivities informed by the global OM reactivity map. The 22 regional model set-ups were then used to quantify biogeochemical process rates, as well as benthic carbon and nutrient fluxes in each province and on the global scale. Model results of regional and global fluxes and rates fall well within the range of observed values and also agree with general globally observed patterns. Results also highlight the role of the deeper ocean for benthic-pelagic cycling and indicate towards a large regional variability in benthic cycling at great depth. This is a first step towards a more refined global estimate of benthic biogeochemical cycling that accounts for the global heterogeneity of the seafloor environment. This aspect is critical to improve our understanding of benthic feedbacks on benthic-pelagic coupling and on the carbon-climate system, which can then be incorporated in benthic processes in Earth System Models. / Les sédiments marins sont un élément clé du cycle mondial du carbone et du système climatique. Ils abritent l’un des plus grands réservoirs de carbone sur Terre, fournissent le seul puits à long terme pour le CO2 atmosphérique, recyclent les nutriments et constituent les archives climatiques les plus importantes. Les processus de la diagénèse précoce dans les sédiments marins sont donc au cœur de notre compréhension des cycles et du climat biogéochimiques passés, présents et futurs. Étant donné que tous les processus diagénétiques précoces peuvent être directement ou indirectement liés à la dégradation de la matière organique (MO), faire progresser cette compréhension nécessite de démêler les différents facteurs qui contrôlent le devenir de la MO (sédimentation, dégradation et enfouissement) à différentes échelles spatiales et temporelles. En général, la dégradation hétérotrophique de la MO dans les sédiments marins est contrôlée par la quantité et, en particulier, la réactivité apparente de la MO qui se dépose sur les sédiments marins. Bien que les contrôles potentiels ((micro) biologiques, chimiques et physiques) de la réactivité de la MO soient de mieux en mieux compris, leur importance relative reste difficile à quantifier. Traditionnellement, des approches de modèle de données intégrées sont utilisées pour quantifier la réactivité apparente de la MO (c’est-à-dire les constantes de vitesse de dégradation de la MO) sur des sites de forage bien étudiés. Ces approches reposent sur des modèles de réaction-transport (RTM) qui tiennent généralement compte des processus de transport (advection, diffusion moléculaire, bioturbation et bio-irrigation) et de réaction (production, consommation, équilibre), mais leur complexité varie. La réactivité apparente de la MO est généralement considérée comme un paramètre libre qui est utilisé pour ajuster les profils de profondeur, les taux de réaction ou les flux d’échange benthique-pélagique observés. À l’heure actuelle, aucun cadre quantitatif n’existe pour prédire la réactivité apparente de la MO dans les zones où aucun ensemble complet de données benthiques n’est disponible.Pour évaluer l’impact de ce manque de connaissance, nous avons exploré la sensibilité des taux de réaction biogéochimiques benthiques, ainsi que des flux d’échange benthique-pélagique aux variations de la réactivité apparente de la MO (c.-à-d. les paramètres du modèle de con- tinuum réactif a et ν) au moyen d’un modèle diagénétique numérique complexe appliqué aux zones de dépôts sur les plateaux, les talus et en haute mer. Les résultats du modèle montrent que la réactivité apparente de la MO exerce un contrôle dominant sur l’ampleur des taux de réaction biogéochimiques et des flux d’échange benthique-pélagique dans différents environ- nements. L’absence d’un cadre général pour quantifier la réactivité de la MO complique donc la paramétrisation des modèles diagénétiques à l’échelle régionale et mondiale et, ainsi, compromet notre capacité à quantifier le couplage benthique-pélagique global en général et la dynamique de dégradation de la MO en particulier.Pour tendre à meilleure connaissance systématique et quantitative de la réactivité de la MO, la réactivité apparente OM (c.-à-d. les paramètres du modèle de continuum réactif a et ν) est quantifiée par modélisation inverse des profils de sédiments organiques de carbone, de sulfate (et de méthane), ainsi que localisation de la zone de transition sulfate-méthane à l’aide d’un modèle diagénétique numérique complexe pour 14 sites individuels à travers différents environnements de dépôt. Les résultats du modèle mettent à nouveau en évidence le contrôle dominant de la réactivité de l’OM sur les taux de réaction biogéochimiques et les flux d’échanges benthiques. De plus, les résultats montrent que les valeurs déterminées inversement déterminées se situent dans une plage étroite (0,1 <ν<0,2). En revanche, les valeurs déterminées s’étendent sur dix ordres de grandeur (1 ·10−3 <ν< 1·107) et sont donc le principal moteur de la variabilité globale de la réactivité OM. L’exploration de ces tendances dans leur contexte environnemental révèle que la réactivité apparente de l’OM est déterminée par un ensemble dynamique de contrôles environnementaux plutôt que par des contrôles environnementaux uniques traditionnellement proposés (par exemple, la profondeur de l’eau, le taux de sédimentation, les flux OM). Cependant, la forte demande de calcul associée à une telle approche de modèle inverse multi-espèces, ainsi que la disponibilité limitée de données complètes sur l’eau interstitielle, limitent le nombre d’estimations apparentes de la réactivité OM. Par conséquent, tout en fournissant des amorces importantes pour une quantification de la réactivité de l’OM à l’échelle mondiale, les résultats du modèle inverse sont loin de fournir un cadre prédictif.Pour surmonter les limites de calcul et étendre la modélisation inverse de la réactivité apparente de l’OM à l’échelle mondiale, le modèle analytique OMEN-SED est étendu en intégrant une approximation nG du modèle de continuum réactif qui est pleinement cohérente avec la structure générale d’OMEN-SED. La nouvelle version OMEN-SED-RCM fournit ainsi l’efficacité de calcul requise pour la détermination inverse de la réactivité apparente de l’OM (c’est-à-dire les paramètres du modèle de continuum réactif a et ν) à l’échelle mondiale. Les capacités du nouveau modèle OMEN-SED-RCM à capturer les modèles locaux et globaux de dynamique diagénétique observés sont rigoureusement testés par les données du modèle, ainsi que la comparaison modèle- modèle.OMEN-SED-RCM est ensuite utilisé pour déterminer inversement la réactivité apparente de l’OM par modélisation inverse de 394 mesures individuelles du taux d’utilisation de l’oxygène dissous (DOU). Le DOU est couramment utilisé comme indicateur de la réactivité de l’OM, il est plus largement disponible que les ensembles de données exhaustifs sur l’eau interstitielle et les cartes benthiques mondiales/régionales des taux d’utilisation de l’oxygène dissous (DOU) ont été dérivées sur la base de l’ensemble de données DOU croissant. Le test de sensibilité montre que, bien que la modélisation inverse des taux de DOU ne fournisse pas une estimation robuste du paramètre RCM ν, c’est un bon indicateur pour le paramètre RCM a. Sur la base des résultats précédents, le paramètre ν a donc été supposé être globalement constant. Les valeurs a déterminées à l’inverse varient selon l’ordre de grandeur, de a = 0,6 an dans la région polaire sud à a = 5, 6 · 106 dans le Pacifique sud oligotrophique central. Malgré une forte hétérogénéité intra et interrégionale dans la réactivité apparente de la MO benthique, un certain nombre de schémas régionaux clairs qui correspondent largement aux observations précédentes émergent. Des réactivités apparentes élevées de l’OM sont généralement observées dans les régions dominées par des sources marines de MO et caractérisées par un naufrage efficace de l’OM et une dégradation limitée pendant le naufrage. En revanche, les réactivités MO apparentes les plus faibles sont observées pour les régions caractérisées par de faibles taux de production primaire marine, en combinaison avec une grande distance du plateau continental et de la pente, ainsi que des colonnes d’eau profonde. Pourtant, les résultats mettent également en évidence l’importance des processus de transport latéral pour la réactivité apparente de l’OM.En particulier, les sédiments des mers profondes au voisinage d’environnements de marge continentale dynamiques ou sous l’influence de forts courants océaniques peuvent recevoir des apports OM de réactivité comparable provenant d’environnements plus productifs et, ainsi, révéler des réactivités OM plus élevées que ce qui était traditionnellement prévu. Enfin, sur la base du lien fort observé entre la réactivité apparente de l’OM (c’est-à-dire le paramètre RCM a) et le taux DOU, une fonction de transfert qui prédit l’ordre de grandeur du paramètre RCM a en fonction de DOU est utilisée pour dériver, pour nos connaissances, la première carte mondiale de la réactivité apparente de l’OM. Les résultats du modèle des flux et des taux régionaux et mondiaux se situent bien dans la gamme des valeurs observées et également d’accord avec les tendances générales observées au niveau mondial. Les résultats mettent également en évidence le rôle de l’océan profond pour le cycle benthique-pélagique et indiquent une grande variabilité régionale du cycle benthique à grande profondeur. Il s’agit d’une première étape vers une estimation mondiale plus précise du cycle biogéochimique benthique qui tient compte de l’hétérogénéité mondiale du milieu marin. Cet aspect est essentiel pour améliorer notre compréhension des rétroactions benthiques sur le couplage benthique-pélagique et sur le système carbone-climat, qui peuvent ensuite être incorporées aux processus benthiques dans les modèles du système terrestre. / Doctorat en Sciences / info:eu-repo/semantics/nonPublished