[pt] O escoamento de suspensões concentradas tem grande importância em diversos segmentos da indústria, representando uma maneira econômica de transportar grandes quantidades de materiais sólidos particulados. Uma das aplicações inclui a etapa de perfuração de poços de petróleo direcionais. No decorrer do processo são gerados sedimentos originários do corte da formação, que são removidos através da operação de limpeza do poço. Durante a limpeza, no trecho de maior inclinação esses sedimentos tendem a se separar da suspensão, pelo efeito gravitacional, formando um leito na parte inferior do anular. Esse leito formado pode causar vários problemas, como redução da taxa de penetração, desgaste prematuro da broca, prisão da coluna de perfuração, fraturamento da formação e torque excessivo na coluna de perfuração. O entendimento do escoamento de suspensões de partículas se torna relevante para o aperfeiçoamento desses processos. Nesse sentido, o objetivo deste trabalho é analisar o escoamento de suspensões de partículas entre duas placas paralelas para estudar a formação de um leito de sedimentos na parte inferior do canal e determinar o efeito dos diferentes mecanismos de migração de partículas neste processo. A formulação matemática do problema inclui as equações de conservação de massa e quantidade de movimento linear e equação de transporte de partículas. Para descrever o transporte de partículas no escoamento foi usado o modelo de fluxo difusivo proposto por Phillips et al. (1992). As equações diferenciais parciais, que descrevem o escoamento de uma suspensão de partículas, são resolvidas pelo método de Elementos Finitos de Galerkin e o sistema não-linear é resolvido através do método de Newton. Os resultados obtidos mostram como a distribuição das partículas sólidas varia com os parâmetros do problema e determina as condições para a formação de um leito de partículas. / [en] The flow of solid particles suspended in a liquid medium have great importance in several industry segments representing an economical way to transport large quantities of solid materials. One of the applications includes the flow during directional well drilling. During the process sediments are generated from the formation cutting, which are removed through the wellbore cleaning. During the cleaning, step near the horizontal section of the well, these sediments tend to separate from the suspension by the action of gravity, forming a stationary bed in the bottom of the annular. This stationary bed can cause problems, such as reducing the penetration rate, premature wear of the drill bit, trapping column, fracturing of the formation and high torque. The complete understanding of the flow of solid particles suspension becomes relevant to the improvement of these processes. In this sense, the main goal of this work is to analyze the flow of solid particle suspensions between two parallel plates to investigate the formation of a stationary bed in the bottom of the channel and to determine the effect of different particle migration mechanisms in this process. The mathematical formulation includes the equations of mass (continuity equation) and momentum conservation. The Diffusive Flux Model proposed by Phillips et al. (1992) was used to describe the particle transport in the flow. The partial differential equations, which describe the flow of solid particles suspension, are solved by the Galerkin/Finite Element Method (GFEM) and the non-linear system is solved using Newton s Method. The results show how the distribution of solid particles varies with the problem parameters and determines the conditions for the formation of a stationary bed.

During the winters in recent years Laholmsbuktens VA's treatment plant in Halmstad has recorded unexcepted levels of phosphorus from the polishing pond. Only between 8 and 20 January 2016 samples indicates a realese of net 75 kg. In winter the pond temperature never goes below about 8oC, which attracts wintering waterfowl. In February 19, 2016 the largest number of birds in the inventory for this thesis was noted, 325 individuals, of which 208 were tufted ducks.  Even if the number of waterfowl at peak levels was to be about 1000 individuals, their combined contribution of phosphorus through droppings into the pond could not be more than 500 g per day. This study proposes that a significant factor is the foraging activity of tufted ducks, which are diving ducks. In search of food at daytime they disturb the sediment at the bottom of the pond, i.e bioturbation.  The higher proportion of particle-bound phosphorus in samples with high phosphorus content also fits well with this hypothesis. A scientific investigation in which the bottom of this part of the pond was stirred up mechanically gave similar proportions between phosphorus and water-soluble phosphorus.

La thèse concerne la modélisation de deux écoulements issus de problèmes géophysiques. Un premier problème a trait à la présence de tourbillons longitudinaux apparaissant dans les cours d'eau. L'origine de ces structures reste indéterminée. On aborde ce problème par une simulation numérique d'un écoulement turbulent cisaillé dans un canal ouvert utilisant un code pseudo-spectral. On tente de voir si un cisaillement de surface même faible est capable ou non de comprendre ces observations. Le second problème est lié à la resuspension des sédiments sur les bords d'une mer ou d'un lac par des ondes internes. Ces ondes existent à cause de la stratification en densité de la colonne d'eau. Lorsque elles s'approchent de la côte, elles se déstructurent générant un cisaillement sur le fond capable de resuspendre du sédiment. On a envisagé à nouveau cette étude par le biais de la simulation numérique directe. On examine comment l'onde interne se brise sur les bords en fonction de (a) la nature de la stratification, (b) la forme de la topographie du fond et (c) l'amplitude des ondes. On calcule dans chaque cas le cisaillement sur le fond. On en déduit le flux et le transport de sédiment dans toute la colonne d'eau. / This thesis studies the modeling of two problems that take their origin from a geophysical context. A first problem is related to the presence of longitudinal vortices which have been measured in rivers. The origin of these structures remains unknown. We address this problem by numerical simulations of a sheared turbulent flows in an open channel using a pseudo-spectral code. We try to determine if the presence of an imposed shear at the surface coupled with a pressure gradient is capable or not to explain these observations. The second study focuses on the sediment resuspension on shores of seas or lakes by the action of internal waves. These waves exist because of density stratification of the water column. When waves approach the shore, their patterns evolve generating a shear on the bottom capable to resuspend sediment. By direct numerical simulations, we analyse how internal waves breaking changes according to (a) stratification, (b) bottom topography and (c) wave amplitude. We compute for each case the shear exerted on the bottom, the sediment flux and transport throughout the water column.

La pollution atmosphérique en milieu urbain a été identifiée comme une cause importante d’impacts sanitaires, y compris de décès prématurés. En particulier, les concentrations ambiantes de polluants gazeux tels que le dioxyde d’azote (NO2) et de particules (PM10 et PM2,5) sont réglementées, ce qui implique que des stratégies de réductions d’émissions doivent être mises en place pour diminuer ces concentrations dans les lieux où la réglementation correspondante n’est pas respectée. Par ailleurs, la pollution atmosphérique peut contribuer à la contamination d’autres milieux, par exemple à travers la contribution des dépôts atmosphériques à la contamination des eaux de ruissellement.Les aspects multifactoriels et multiéchelle de la pollution en ville rendent l’identification des sources difficile. En effet, le milieu urbain est un espace hétérogène caractérisé par des structures architecturales complexes (bâti ancien côtoyant un bâti plus moderne, zones résidentielles, commerciales, industrielles, axes routiers…), des émissions de polluants atmosphériques non uniformes et par conséquent une exposition de la population à la pollution qui est variable dans l’espace et le temps.La modélisation de la pollution atmosphérique urbaine a pour vocation de comprendre l’origine des polluants, leur étendue spatiale et leur niveau de concentrations/dépôt. Certains polluants ont des temps de résidence long et peuvent séjourner plusieurs semaines dans l’atmosphère (PM2,5) et donc être transportés sur de longues distances, d’autres au contraire, sont plus locaux (NOx en proximité du trafic). La répartition spatiale d’un polluant dépendra alors de plusieurs facteurs et notamment des surfaces rencontrées. La qualité de l’air, elle, dépend fortement des conditions météorologiques, du bâti (rue-canyon) et des émissions.L’objectif de cette thèse est de traiter certains de ces aspects en modélisant : (1) la pollution urbaine de fond avec un modèle de chimie-transport (Polyphemus/POLAIR3D), qui permet d’estimer les dépôts de polluants atmosphériques par type de surfaces urbaines (toits, murs et chaussées), (2) la pollution à l’échelle de la rue en intégrant explicitement les effets du bâti de manière tridimensionnelle avec d’une part un modèle multiéchelle de chimie-transport (SinG) et d’autre part un modèle de mécanique des fluides (Code_Saturne) et (3) un processus de micro-échelle qui est la réémission des particules présentes sur la chaussée par le trafic routier avec trois formulations différentes (déterministe, semi-empirique et empirique). L’intérêt de cette thèse est de pouvoir comparer et évaluer l’opérabilité et la performance de plusieurs modèles de qualité de l’air à plusieurs échelles (région, quartier et rue) afin de mieux appréhender la caractérisation de la qualité de l’air en milieu urbain / Urban air pollution has been identified as an important cause of health impacts, including premature deaths. In particular, ambient concentrations of gaseous pollutants such as nitrogen dioxide (NO2) and particulate matter (PM10 and PM2.5) are regulated, which means that emission reduction strategies must be put in place to reduce these concentrations in places where the corresponding regulations are not respected. Besides, air pollution can contribute to the contamination of other media, for example through the contribution of atmospheric deposition to runoff contamination.The multifactorial and multiscale aspects of urban make the pollution sources difficult to identify. Indeed, the urban environment is a heterogeneous space characterized by complex architectural structures (old buildings alongside a more modern building, residential, commercial, industrial zones, roads, etc.), non-uniform atmospheric pollutant emissions and therefore the population exposure to pollution is variable in space and time.The modeling of urban air pollution aims to understand the origin of pollutants, their spatial extent and their concentration/deposition levels. Some pollutants have long residence times and can stay several weeks in the atmosphere (PM2.5) and therefore be transported over long distances, while others are more local (NOx in the vicinity of traffic). The spatial distribution of a pollutant will therefore depend on several factors, and in particular on the surfaces encountered. Air quality depends strongly on weather, buildings (canyon-street) and emissions.The aim of this thesis is to address some of these aspects by modeling: (1) urban background pollution with a transport-chemical model (Polyphemus / POLAIR3D), which makes it possible to estimate atmospheric pollutants by type of urban surfaces (roofs, walls and roadways), (2) street-level pollution by explicitly integrating the effects of the building in a three-dimensional way with a multi-scale model of transport chemistry (SinG) and (3) a microscale process which is the traffic-related resuspension of the particles present on the road surface with three different formulations (deterministic, semi-empirical and empirical).The interest of this thesis is to compare and evaluate the operability and performance of several air quality models at different scales (region, neighborhood and street) in order to better understand the characterization of air quality in an urban environment

[pt] Após a década de 80 tornou-se frequente a utilização de poços direcionais, tanto poços horizontais quanto os de longo alcance, nas operações de desenvolvimentos de campos petrolíferos, os quais permitiram grande avanço na exploração. Este cenário, porém, traz grandes desafios para operações de perfuração relacionadas à limpeza de poços. A limpeza de poços consiste na remoção dos cascalhos de dentro do anular do poço através da circulação do fluido de perfuração. Devido à inclinação do poço, os cascalhos sofrem a ação da gravidade sendo empurrados para o fundo do canal, já que possuem densidade maior que a da fase líquida, assim, transportados a uma velocidade menor que a velocidade do escoamento. Ao se depositarem no fundo do canal, formam um leito estacionário, obstruindo parte do anular e diminuindo a vazão, o que gera problemas, como por exemplo, redução da taxa de penetração, desgaste prematuro da broca, elevação do torque e arraste, aprisionamento da coluna, perda de circulação, dentre outros, podendo gerar a perda do poço. Desta forma, o perfeito entendimento do processo de sedimentação e transporte de partículas sólidas suspensas em fluido é fundamental para a otimização do processo de perfuração de poços. Este trabalho analisa o escoamento laminar bidimensional de suspensões de partículas sólidas devido a um gradiente de pressão entre duas placas paralelas, representando uma descrição simplificada do escoamento que ocorre em um anular de poço durante o processo de perfuração. O perfil do leito de partículas ao longo do canal e a relação vazão-diferença de pressão para diferentes condições de escoamento são determinados pela solução numérica das equações que descrevem o problema. A formulação matemática leva a um sistema acoplado de três equações diferenciais: conservação de massa e de quantidade de movimento e a equação de transporte, que engloba os efeitos de difusão de partículas devido à frequência de interação entre as partículas, ao gradiente de viscosidade e à diferença de densidade entre o líquido e as partículas. O sistema é resolvido pela técnica de Elementos Finitos, através do método de Galerkin. Os resultados obtidos serão de extrema importância no desenvolvimento de modelos mais precisos que descrevam o processo de transporte de sólidos em anulares de poços. / [en] After the 80 s, the use of directional wells, both horizontal and long range wells, became frequent in the development of oil fields, which allowed great progress in exploration. This scenario, however, brings great challenges to operations related to wellbore cleaning. Wellbore cleaning consists in the removal of cuttings from within the annular through the circulation of drilling fluid. Due to the inclination of the well, the cuttings undergo the action of gravity and more to the bottom of the channel, as they have higher density than the liquid phase. They may be transported with a speed less than the speed of the liquid flow. When deposited on the channel, the cuttings form a stationary bed, blocking part of the annular and decreasing the flow rate that causes problems, such as reducing the rate of penetration, premature wear of the bit, high torque and drag, trapping column, loss of circulation and others, which may cause the loss of the well. Therefore, the fundamental understanding of particle sedimentation and transport in a suspending flowing liquid is necessary for drilling operation design and optimization. This research studies the laminar two-dimensional flow of solid particles suspended in a liquid due to a pressure gradient between two parallel plates, representing a simplified description of the flow that occurs in an annular during the drilling process. The profile of the particle bed along the channel and the flow rate pressure difference relationship for different flow conditions are determined. The mathematical formulation leads to a coupled system of three differential equations: mass and momentum conservation and transport equation, which includes the effects of particle diffusion due to the frequency of interaction between the particles, the gradient of viscosity and the difference density between the liquid and the particles. The system is solved by the finite element method Galerkin. The results will be of extreme importance in the development of more accurate models that describe the solids transport process in annular space.

O presente estudo visou investigar os efeitos da ressuspensão do sedimento e enriquecimento orgânico por diferentes microalgas na estrutura das comunidades microbianas do sedimento. Para tanto dois experimentos laboratoriais separados foram realizados (Nov-Dez/2009 e Abr-Maio/2011) com o intuito de simular as condições de ressuspensão e pulsos de produtividade primária observadas em campo e assim observar como a comunidade microbiana do sedimento é influenciada por esses eventos. Ambos os experimentos foram mantidos por um total de 30 dias após o tratamento, durante os quais amostras para análises sedimentares, densidade de procariotos e composição da comunidade bacteriana foram tomadas em seis períodos diferentes. A camada superficial do sedimento foi estudada mais detalhadamente e mostrou que tanto a chegada de material algal quanto a ressuspensão são responsáveis por mudanças significativas na densidade, metabolismo e composição da comunidade bacteriana do sedimento. Ainda, a chegada de diferentes tipos de algas ao sedimento (fitoflagelados e diatomáceas) levou a diferentes repostas tanto na densidade quanto na diversidade dos micro-organismos sedimentares. A estrutura vertical dos micro-organismos na coluna sedimentar também foi estudada. A chegada de material algal no sedimento não levou a grandes mudanças na estrutura da comunidade mais profundas da coluna sedimentar. A estabilidade criada pelo ambiente experimental parece ter levado a um aumento tanto da densidade quanto da diversidade microbiana na camada intermediária do sedimento, em ambos os tratamentos e no controle. Já a ressuspensão parece influenciar de forma mais efetiva a distribuição dos micro-organismos na coluna sedimentar, devido a mistura da coluna sedimentar e mudanças nas condições redox das camadas sedimentares. Concluindo, tanto a chegada de alimento no sedimento, como eventos de ressuspensão são responsáveis por mudanças significativas na comunidade microbiana dos sedimentos costeiros. / The present study aimed to investigate the effects of sediment resuspension and organic enrichment by different microalgae on the sedimentary microbial community structure. We run two separate laboratory experiments (Nov-Dec/2009 and Apr-May/2011) to simulate resuspension conditions and pulses of primary productivity observed in the field, and analyze how these events affect the microbial community. Both experiments were maintained for a total of 30 days following treatment when samples were taken for sedimentary analysis, prokaryotic density and bacterial community analyses at six different sampling times. The sediment surface layer was studied in more detail, and showed that both the input of algal material and resuspension are responsible for significant changes in density, metabolism and bacterial community composition. Also, the arrival of different types of algae to the sediment (phytoflagellates and diatoms) led to different responses in both density and diversity of sedimentary microorganisms. The vertical structure of microorganisms in the sediment column was also studied. The arrival of algal material in the sediment did not show important changes in community structure of the deeper sedimentary layers. The stability created by the experimental environment seems to increase both the density and diversity of microbes in the middle layer of sediment in both treatments and control. On the other hand resuspension seems to influence more effectively the distribution of microorganisms in the sedimentary column due to sediment mixing and changes in redox conditions of different layers. In conclusion, both the arrival of food on the sediment and resuspension events is responsible for important changes in the coastal sediment microbial communities.

Les écosystèmes littoraux lacustres, ou ceintures des lacs, ont une valeur écologique très importante. Zones de transition et d'échanges entre les écosystèmes terrestre et aquatique, les rives des lacs et leurs zones littorales sont reconnues pour abriter une forte biodiversité, dont des plantes aquatiques visibles à l'œil nu : les macrophytes. La structure spatiale, l'abondance et la composition spécifique de ces peuplements végétaux sont conditionnées par le caractère et le fonctionnement physiques des biotopes littoraux lacustres. Ce travail de thèse est dédié à l'acquisition de connaissances sur les relations entre les peuplements macrophytiques et les déterminants physiques de biotopes littoraux lacustres dans les lacs peu profonds. Il s'applique à définir, à différentes échelles, les préférences hydroécologiques et la structure fonctionnelle et spatiale de communautés et populations de plantes aquatiques. Cette recherche s'appuie sur la modélisation et sur des observations, mesures et prélèvements menés in situ sur les macrophytes et les variables environnementales dans les grands lacs naturels du littoral aquitain. Les principaux résultats indiquent que l'action du vent et des vagues, la pente des rives, la profondeur, la granulométrie et la matière organique des sédiments influencent l'organisation spatiale et les assemblages d'espèces de macrophytes. Ces variables peuvent être utilisées pour prédire la distribution potentielle de certaines communautés végétales. Les altérations anthropiques de l'hydromorphologie favorisent le développement des espèces exotiques tout en compromettant le maintien des espèces indigènes patrimoniales. Les enjeux liés à la gestion des espèces exotiques et des espèces indigènes ont également été identifiés à partir d'une analyse diachronique des dynamiques écologiques de la végétation depuis quarante ans dans les lacs aquitains. Il est désormais urgent d'établir une stratégie de conservation des espèces indigènes, voire de restauration pour les patrimoniales, et de limiter la dispersion des espèces exotiques dans les lacs. Présentant de nombreuses analogies avec les lacs d'Europe du Nord tels que les softwater lakes ou les Lobelia lakes, les processus écologiques en cours dans les lacs du sud-ouest de la France pourraient préfigurer la situation à venir pour l'ensemble des lacs du même type dans le contexte du changement global. Les écosystèmes littoraux lacustres concentrent des enjeux écologiques, économiques et sociétaux, soulevant des questions et problématiques scientifiques sur leur fonctionnement et sur la bioindication de leur état écologique qu'il est nécessaire de continuer à explorer. / Lakeshores zones are of very high ecological value. As they are ecotones between terrestrial and aquatic ecosystems, lake shoreline and littoral zones are characterized by a high level of biodiversity, including macroscopic aquatic plants known as macrophytes. Plant distribution, abundance and species composition are determined by physical features of lakeshores. This work aims to assess relationships between macrophyte populations and communities and hydromorphological components in shallow lakes at different scales. Plant and environmental variables were modeled or collected on the field in large lakes located along the western French Atlantic coast. Wind and wave action, slope, depth, sediment grain size and organic matter content are well known for their influence on macrophyte species distribution and assemblages. Physical variables can be used to predict the potential distribution of plant communities. Anthropogenic physical disturbances enhances the development of invasive species while they threaten rare and endangered native species. Plant management issues were also highlighted from a long-term field data (fourty years) analysis of macrophyte dynamics in these shallow lakes. Management strategies are needed for the conservation of native species, or even their restoration, and the control of alien species spread in these lakes. Similar in some ways to northern European lakes such as softwater lakes or Lobelia lakes, the ecological processes identified in these Atlantic shallow lakes could foreshadow the future situation for all lakes of the same type in the context of global change. Lakeshore ecosystems gather ecological, economic and societal issues, raising scientific questions and issues about their functioning and the bioindication of their ecological status that needs to be further explored.

O presente estudo visou investigar os efeitos da ressuspensão do sedimento e enriquecimento orgânico por diferentes microalgas na estrutura das comunidades microbianas do sedimento. Para tanto dois experimentos laboratoriais separados foram realizados (Nov-Dez/2009 e Abr-Maio/2011) com o intuito de simular as condições de ressuspensão e pulsos de produtividade primária observadas em campo e assim observar como a comunidade microbiana do sedimento é influenciada por esses eventos. Ambos os experimentos foram mantidos por um total de 30 dias após o tratamento, durante os quais amostras para análises sedimentares, densidade de procariotos e composição da comunidade bacteriana foram tomadas em seis períodos diferentes. A camada superficial do sedimento foi estudada mais detalhadamente e mostrou que tanto a chegada de material algal quanto a ressuspensão são responsáveis por mudanças significativas na densidade, metabolismo e composição da comunidade bacteriana do sedimento. Ainda, a chegada de diferentes tipos de algas ao sedimento (fitoflagelados e diatomáceas) levou a diferentes repostas tanto na densidade quanto na diversidade dos micro-organismos sedimentares. A estrutura vertical dos micro-organismos na coluna sedimentar também foi estudada. A chegada de material algal no sedimento não levou a grandes mudanças na estrutura da comunidade mais profundas da coluna sedimentar. A estabilidade criada pelo ambiente experimental parece ter levado a um aumento tanto da densidade quanto da diversidade microbiana na camada intermediária do sedimento, em ambos os tratamentos e no controle. Já a ressuspensão parece influenciar de forma mais efetiva a distribuição dos micro-organismos na coluna sedimentar, devido a mistura da coluna sedimentar e mudanças nas condições redox das camadas sedimentares. Concluindo, tanto a chegada de alimento no sedimento, como eventos de ressuspensão são responsáveis por mudanças significativas na comunidade microbiana dos sedimentos costeiros. / The present study aimed to investigate the effects of sediment resuspension and organic enrichment by different microalgae on the sedimentary microbial community structure. We run two separate laboratory experiments (Nov-Dec/2009 and Apr-May/2011) to simulate resuspension conditions and pulses of primary productivity observed in the field, and analyze how these events affect the microbial community. Both experiments were maintained for a total of 30 days following treatment when samples were taken for sedimentary analysis, prokaryotic density and bacterial community analyses at six different sampling times. The sediment surface layer was studied in more detail, and showed that both the input of algal material and resuspension are responsible for significant changes in density, metabolism and bacterial community composition. Also, the arrival of different types of algae to the sediment (phytoflagellates and diatoms) led to different responses in both density and diversity of sedimentary microorganisms. The vertical structure of microorganisms in the sediment column was also studied. The arrival of algal material in the sediment did not show important changes in community structure of the deeper sedimentary layers. The stability created by the experimental environment seems to increase both the density and diversity of microbes in the middle layer of sediment in both treatments and control. On the other hand resuspension seems to influence more effectively the distribution of microorganisms in the sedimentary column due to sediment mixing and changes in redox conditions of different layers. In conclusion, both the arrival of food on the sediment and resuspension events is responsible for important changes in the coastal sediment microbial communities.

Fundação Carlos Chagas Filho de Amparo a Pesquisa do Estado do Rio de Janeiro / A pesquisa aqui apresentada amostrou a plataforma continental e talude superior entre Ubatuba (SP) e o cabo Búzios (RJ), em dois projetos de escala local e de meso-escala. A campanha entre Ubatuba e o cabo Frio foi realizada no âmbito do projeto Oceano-Rio: levantamentos oceanográficos integrados ao largo do Estado do Rio de Janeiro, realizado em colaboração com o Ministério de Ciência e Tecnologia (MCT) e com a cooperação da Marinha do Brasil (MB), a bordo do Navio Hidro-oceanográfico Cruzeiro do Sul. Dos dados coletados nesta campanha oceanográfica, foram analisados os dados de CTD, concentração de oxigênio dissolvido, fluorescência, transmissividade, atenuação, retro-espalhamento além de amostras de água para a determinação direta da concentração de material particulado em suspensão (MPS). No experimento de menor escala, entre o cabo Frio e o cabo Búzios, além destes dados, foi realizado um fundeio entre 02 e 30 de julho de 2011, que amostrou a intensidade do eco, as correntes e as ondas. As análises realizadas permitiram observar uma grande abrangência da massa dágua característica da Ressurgência sobre a plataforma continental entre Ubatuba (SP) e cabo Búzios (RJ), inclusive em regiões muito rasas. A ressurgência nem sempre ocorreu associada aos ventos NE, sugerindo que a ocorrência de vórtices tem grande influência sobre o Sistema de Ressurgência de Cabo Frio. O padrão de distribuição de MPS na região é muito influenciado pela ressuspensão dos sedimentos de fundo (aumentada durante as tempestades, quando a coluna dágua passa a apresentar maiores concentrações de MPS), produção fitoplanctônica e aporte das baías costeiras. Outros processos que parecem influenciar este padrão são os vórtices e as ondas internas no talude. A complexidade da interação destas diferentes fontes de MPS e processos associados à sua distribuição ficou evidenciada no processo de conversão dos sinais óticos do transmissômetro e nefelômetro em concentração de MPS. Apesar desta dificuldade associada à grande variabilidade das características do MPS, as análises dos testes de conversão do sinal ótico em concentração de MPS permitem concluir que as melhores conversões podem ser obtidas após a inspeção visual das concentrações de MPS medidos (filtração) e remoção das amostras que não seguem a tendência geral esperada de dispersão sinal ótico versus concentração de MPS. / The research presented here sampled the continental shelf and upper slope from Ubatuba (SP) to Búzios cape (RJ) on two projects at local and meso-scale. The cruise between Cape Frio and Ubatuba was performed under the project Oceano-Rio: levantamentos oceanográficos integrados ao largo do Estado do Rio de Janeiro, conducted in collaboration with the Ministry of Science and Technology (MCT) and the Brazilian Navy aboard the Cruzeiro do Sul Hydro-Oceanographic vessel. Of oceanographic data collected in this campaign, we analyzed data from CTD, dissolved oxygen, fluorescence, transmissivity, attenuation, back-scattering as well as water samples for the direct determination of the concentration of suspended particulate matter (SPM). In the experiment between Cabo Frio and Búzios capes, in addition to these data, an Acoustic Doppler Current Profiler (ADCP) was positioned near the bottom and collected data from the echo intensity, currents and waves, between 02 and 30 July 2011. The analysis allowed to observe a wide range of water mass characteristic of upwelling on the continental shelf from Ubatuba (SP) to Búzios cape (RJ), even in very shallow regions. The resurgence was not always associated with the NE winds, suggesting that the occurrence of vortices has a great influence on the Upwelling System of Cabo Frio. The distribution pattern of SPM in the region is strongly influenced by resuspension of bottom sediments (enhanced during storms, when the water column begins to show higher concentrations of SPM), phytoplankton production and supply of coastal bays. Other processes that seem to influence this pattern are the vortices and internal waves on the slope. The complexity of the interaction of these different sources of MPS and processes associated with its distribution was evident in the process of converting the optical signals (transmissivity, attenuation and back-scattering) at a concentration of SPM. Despite this difficulty associated with the high variability of the characteristics of the SPM, the analysis of several tests that were carried out to convert optical signals into concentrations of SPM revealed that significantly improved results may be achieved after visual inspection of the directly determined values (through filtration of water samples) and removal of samples that do not follow the expected trend in regressions of the optical signals against concentrations.

Fundação Carlos Chagas Filho de Amparo a Pesquisa do Estado do Rio de Janeiro / A pesquisa aqui apresentada amostrou a plataforma continental e talude superior entre Ubatuba (SP) e o cabo Búzios (RJ), em dois projetos de escala local e de meso-escala. A campanha entre Ubatuba e o cabo Frio foi realizada no âmbito do projeto Oceano-Rio: levantamentos oceanográficos integrados ao largo do Estado do Rio de Janeiro, realizado em colaboração com o Ministério de Ciência e Tecnologia (MCT) e com a cooperação da Marinha do Brasil (MB), a bordo do Navio Hidro-oceanográfico Cruzeiro do Sul. Dos dados coletados nesta campanha oceanográfica, foram analisados os dados de CTD, concentração de oxigênio dissolvido, fluorescência, transmissividade, atenuação, retro-espalhamento além de amostras de água para a determinação direta da concentração de material particulado em suspensão (MPS). No experimento de menor escala, entre o cabo Frio e o cabo Búzios, além destes dados, foi realizado um fundeio entre 02 e 30 de julho de 2011, que amostrou a intensidade do eco, as correntes e as ondas. As análises realizadas permitiram observar uma grande abrangência da massa dágua característica da Ressurgência sobre a plataforma continental entre Ubatuba (SP) e cabo Búzios (RJ), inclusive em regiões muito rasas. A ressurgência nem sempre ocorreu associada aos ventos NE, sugerindo que a ocorrência de vórtices tem grande influência sobre o Sistema de Ressurgência de Cabo Frio. O padrão de distribuição de MPS na região é muito influenciado pela ressuspensão dos sedimentos de fundo (aumentada durante as tempestades, quando a coluna dágua passa a apresentar maiores concentrações de MPS), produção fitoplanctônica e aporte das baías costeiras. Outros processos que parecem influenciar este padrão são os vórtices e as ondas internas no talude. A complexidade da interação destas diferentes fontes de MPS e processos associados à sua distribuição ficou evidenciada no processo de conversão dos sinais óticos do transmissômetro e nefelômetro em concentração de MPS. Apesar desta dificuldade associada à grande variabilidade das características do MPS, as análises dos testes de conversão do sinal ótico em concentração de MPS permitem concluir que as melhores conversões podem ser obtidas após a inspeção visual das concentrações de MPS medidos (filtração) e remoção das amostras que não seguem a tendência geral esperada de dispersão sinal ótico versus concentração de MPS. / The research presented here sampled the continental shelf and upper slope from Ubatuba (SP) to Búzios cape (RJ) on two projects at local and meso-scale. The cruise between Cape Frio and Ubatuba was performed under the project Oceano-Rio: levantamentos oceanográficos integrados ao largo do Estado do Rio de Janeiro, conducted in collaboration with the Ministry of Science and Technology (MCT) and the Brazilian Navy aboard the Cruzeiro do Sul Hydro-Oceanographic vessel. Of oceanographic data collected in this campaign, we analyzed data from CTD, dissolved oxygen, fluorescence, transmissivity, attenuation, back-scattering as well as water samples for the direct determination of the concentration of suspended particulate matter (SPM). In the experiment between Cabo Frio and Búzios capes, in addition to these data, an Acoustic Doppler Current Profiler (ADCP) was positioned near the bottom and collected data from the echo intensity, currents and waves, between 02 and 30 July 2011. The analysis allowed to observe a wide range of water mass characteristic of upwelling on the continental shelf from Ubatuba (SP) to Búzios cape (RJ), even in very shallow regions. The resurgence was not always associated with the NE winds, suggesting that the occurrence of vortices has a great influence on the Upwelling System of Cabo Frio. The distribution pattern of SPM in the region is strongly influenced by resuspension of bottom sediments (enhanced during storms, when the water column begins to show higher concentrations of SPM), phytoplankton production and supply of coastal bays. Other processes that seem to influence this pattern are the vortices and internal waves on the slope. The complexity of the interaction of these different sources of MPS and processes associated with its distribution was evident in the process of converting the optical signals (transmissivity, attenuation and back-scattering) at a concentration of SPM. Despite this difficulty associated with the high variability of the characteristics of the SPM, the analysis of several tests that were carried out to convert optical signals into concentrations of SPM revealed that significantly improved results may be achieved after visual inspection of the directly determined values (through filtration of water samples) and removal of samples that do not follow the expected trend in regressions of the optical signals against concentrations.