O principal objetivo desse trabalho foi analisar a influência das condições ambientais na higidez das larvas de engraulidídeos da plataforma continental ao largo de Santos (24o49\'S - 23o49\'S e 46o55\'W - 45o24\'W). As coletas foram realizadas em dois cruzeiros oceanográficos (setembro de 2005 e março de 2006). Verificou-se diferença nas condições hidrográficas entre as duas campanhas de coletas, sendo que em setembro de 2005 houve maior influência de descarga de águas estuarinas na plataforma, enquanto em março de 2006 houve intrusão da Água Central do Atlântico Sul. As duas situações geraram estratificação vertical e favoreceram a entrada de nutrientes no sistema, o que gera enriquecimento da zona eufótica e beneficia as cadeias tróficas locais. Para avaliar a condição de higidez das larvas, foram utilizados indicadores morfológicos (relação massa-comprimento, fator de condição, altura do corpo da larva, relação entre altura da cabeça e diâmetro do olho) e bioquímicos (quantidade de proteína e relação proteína/DNA). Os indicadores apontaram melhor condição relativa, para as larvas coletadas em março de 2006, que pode ser conseqüência da ocorrência de uma intensa estratificação vertical na coluna de água e de uma maior estabilidade gravitacional em março de 2006, proporcionando maior concentração de nutrientes e ocasionando aumento na densidade e melhora na condição das populações planctônicas. / The aim of this study was to analyze influence of environmental conditions on health of engraulidid larvae of the continental shelf off Santos (24º49´S - 23º49´S e 46º55´W - 45º24´W). Samples were collected during two oceanographic cruises (September 2005 and March 2006). Differences among hydrographic conditions were verified between surveys: in September there was a major influence of the estuarine water discharge in the inner shelf, whereas in March there was an intrusion of the South Atlantic Central Water (SACW) in the region. The two conditions generated vertical stratification and improved the pelagic food web, in which fish larvae participate. Morphological (weight-length relation, condition factor, larvae body height, head height-eye diameter relation) and biochemical (protein quantity and protein/DNA relation) indicators were used to evaluate the larvae health condition. Results showed better relative condition of larvae collected in March 2006 that can be a consequence of the intense water column vertical stratification and gravitational stability in March 2006, providing higher nutrients concentration, increasing density of organisms and improving condition of planktonic populations.

A fim de avaliar a influência do sistema estuarino de Santos sobre os Nematoda da plataforma continental adjacente, a densidade, composição genérica e diversidade desse grupo foram analisadas e relacionadas com o tipo de sedimento, teor de matéria orgânica e biomassa de fitopigmentos. Para isso, o sedimento foi coletado em seis estações, no inverno/2005 e verão/2006, com um amostrador do tipo box-corer, do qual foram retiradas amostras para a meiofauna com um tubo de 4,9 cm2 de área superficial e 10 cm de altura. Os Nematoda representaram mais de 95% da meiofauna, com densidades médias de 2472±1794 ind.10cm-2 no inverno/2005 e de 2606±2017 ind.10cm-2 no verão/2006. A influência do sistema estuarino de Santos restringiu-se às áreas na saída da baía de Santos e do canal de Bertioga e deu-se através do aporte de sedimentos finos e de matéria orgânica, que foi mais evidente no verão devido à maior pluviosidade. Nessas áreas foram observadas menores densidades e maior abundância de gêneros depositívoros, como Sabatieria e Terschellingia e da família Xyalidae. Nas outras estações rasas com sedimento arenoso, bem selecionado e com biomassa de clorofila-a relativamente alta, as densidades foram as mais altas e predominaram Chromadorita e Microlaimus, herbívoros/comedores de epistrato. Nas estações mais profundas, com sedimento mais finos, a densidade e diversidade foram menores e Sabatieria foi dominante. Portanto, além do sistema estuarino, a profundidade e o hidrodinamismo local, que determinam as condições sedimentares e tróficas, foram fatores importantes para as associações dos Nematoda. / To assess the influence of Santos estuarine system on the nematodes of the adjacent continental shelf, the density, composition and generic diversity of this group were analyzed and related to the sediment type, organic matter content and phytopigments biomass. The sediment was collected at six stations, in the winter of 2005 and summer of 2006, with a box-corer from which meiofauna samples were taken with a 4.9 cm2 superficial area and 10 cm height corer. Nematodes represented more than 95% of the total meiofauna, and their average densities were 2,472±1,794 ind.10cm-2 in the winter/2005 and 2,606±2,017 ind.10cm-2 in the summer/2006. The influence of Santos estuarine system was restricted to the closest areas to Santos bay and Bertioga channel and it was observed through the contribution of fine sediments and organic matter, which was more evident in the summer due to higher rainfall. In these areas, lower nematodes densities were found as higher abundance of deposit feeders genera, like Sabatieria and Terschellingia, and from the Xyalidae family. In the other shallow stations with well sorted sands and relatively high chlorophyll-a biomasses, densities were the highest and Chromadorita and Microlaimus, herbivorous/epistrate feeders, were predominant. In the deepest stations with finer sediments, the densities and diversities were the lowest and Sabatieria was dominant. Therefore, apart from the estuarine system, the depth and local hydrodynamics, which determines the sediment and trophic conditions, were important factors for the nematodes assemblages.

Este trabalho analisou dados correntográficos, de três projetos distintos na Plataforma Continental Interna do Estado de São Paulo, além de implementar um modelo numérico, com objetivo de determinar a importância relativa das diversas forçantes que atuam na região. Foram analisados o campo de densidades, a ação dos ventos, das marés e os aportes fluviais, dos sistemas estuarinos de Santos e Cananéia, no condicionamento hidrodinâmico da Plataforma Continental Interna do Estado de São Paulo. Em todos os pontos de análise, as correntes e os ventos apresentaram frequências dominantes na banda subinercial do espectro, com coeficiente de correlação dentro do intervalo de confiança de 95%. Os resultados obtidos pelas simulações numéricas foram considerados bons, visto que apresentaram valores elevados de skill para a componente paralela à costa das correntes nas simulações de validação do modelo. Quanto às forçantes de movimentos, constatou-se que os aportes fluviais aplicados não foram suficientes para reproduzir o campo termohalino médio da região e nem as correntes associadas à estes campos. Os movimentos gerados pelos campos termohalinos são bastantes significativos para o período de verão. A forçante meteorológica gerou movimentos bastante coerentes com as observações para o período de inverno. A forçante de maré apresentou alguma contribuição para a componente perpendicular à costa, mas foi quase insignificante para a componente paralela à costa das correntes. / This work analysed current meter data of three projects in the inner Continental Shelf of Sao Paulo State. The analysis is complemented with a numerical model in order to determine the relative importance of the forcings that act in the region. It was analysed the mean density field, winds, tides and the continental fresh water discharges of the estuarine regions of Santos and Cananeia in the hydrodynamic conditioning of the Sao Paulo inner Continental Shelf. In all analysis, the winds and currents presented the dominant frequencies in the subinercial band of the spectrum, with relatively small lag correlation coefficients between currents and winds, but whitin the confidence level of 95%. The numerical simulations presented good coherence with the observations, with a high skill for the alongshore current in the validation simulations. About the forcings, the river discharges was not be able to maintain the mean thermohaline field and the currents associated to them. The mean currents generated by the thermohaline fields are quite significant for the summer period. The meteorological forcing generated movements very coherent with the observations for the winter period. The tidal forcing have some contribution in the crosshore component of the current, but was almost insignificant for the alongshore component.

O presente trabalho visa avaliar a mobilidade de sedimentos na plataforma continental do Estado de São Paulo levando em conta a propagação de ondas e o tipo de sedimento. Com base no clima de ondas da região, resultante do modelo global de ondas WAVEWATCH-III, o modelo MIKE-21 (SW) foi aplicado para avaliar os processos de transformação de ondas a medida em que elas avançam sobre a plataforma continental. As ondas predominantes são as de sul com 36% e leste com 34%, variando de 1 a 2,5 metros de altura e 6 a 10 segundos de período. Esses dados formam a condição de contorno externa do modelo que fornece as informações necessárias para as estimativas de mobilidade sedimentar. Este processo foi avaliado através da aplicação de uma aproximação empírica onde a máxima velocidade orbital de fundo deve ser maior que a velocidade crítica de fundo. A altura significativa e período médio chegam a remobilizar areia fina até 40 m, areia muito fina até 45 m e silte até 60 m de profundidade. Altura máxima e período de pico, remobilizam areia fina até 60 m, areia muito fina até 80 m e silte até 90m de profundidade. / This study aims to evaluate the mobility of sediments on continental shelf of São Paulo State considering wave propagation and sediment type. Based on wave climate of the region resulting from global wave model WAVEWATCH-III, numerical model MIKE-21 (SW) was applied to evaluate wave transformation processes as they propagate over the continental shelf. Waves from south and east are predominant with 36% and 34%, respectively, wave height ranged from 1 to 2.5 meters and wave period varied between 6 and 10 seconds. These data form boundary condition of the model and provides necessary information to estimate sediment mobility. In order to evaluate this process, an empirical approach was applied, where maximum bed orbital velocity must exceed a critical bottom velocity. The significant wave height and mean period mobilize fine sand up to 40 m, very fine sand up to 45 m and silt up to 60 meters deep. Maximum height and peak period, mobilize fine sand up to 60 m, very fine sand up to 80 m and silt up to 90 meters deep.

Cumáceos são crustáceos peracáridos cosmopolitas que se distribuem desde a zona entre-marés até os fundos abissais. Habitam fundos arenosos e lodosos e eventualmente são encontrados no ambiente pelagial. Apesar de sua importância na dieta de diversos organismos, e de serem considerados bons indicadores ambientais, poucos estudos ecológicos foram realizados com o grupo no Brasil, não havendo uma avaliação do papel que desempenham na estruturação e funcionamento do ecossistema bêntico. O presente estudo tem por objetivo descrever a composição e a distribuição espaço-temporal das espécies de Cumacea, investigar a existência de comunidades e sua estrutura, identificar os principais fatores responsáveis pelos agrupamentos encontrados e avaliar o efeito das mudanças sazonais da estrutura oceanográfica sobre os descritores utilizados. Para tanto, foi realizada uma campanha oceanográfica no inverno de 2005 e outra no verão de 2006, em uma grade de 21 estações situadas na plataforma continental sudeste, entre São Sebastião e Peruíbe, amostradas por meio de Box Corer e Draga. Os resultados mostraram a presença de 31 espécies de Cumacea em toda a área, sendo 24 no inverno e 28 no verão. Os valores mais elevados de densidade, diversidade e riqueza situaram-se nas estações próximas a isóbata de 50m em ambas as campanhas, podendo ser atribuídos à presença da Água Central do Atlântico Sul sobre essas áreas, uma vez que ela promove intensa eutrofização da coluna da água e também confere maior estabilidade ambiental devido a formação de termoclina na coluna da água. Os resultados mostraram ainda que a profundidade e as características granulométricas do sedimento foram os principais fatores determinantes da composição e distribuição das comunidades de Cumacea. Desta forma foram evidenciadas três faixas de profundidade paralelas à costa com comportamento oceanográfico próprio: zona rasa, zona intermediária e zona profunda, cada qual apresentando espécies características e organizadas em estruturas ecologicamente distintas, caracterizando comunidades. A utilização de diferentes aparelhos, como Box Corer e Draga, permitiu complementação amostral da fauna, propiciando um conjunto de informações abrangentes e que permitiu a realização de um estudo mais robusto. / Cumaceans are Peracarid crustaceans distributed worldwide, occurring from intertidal zone to abyssal plains. They inhabit sandy and muddy bottoms, and are eventually found in the pelagic environment. Despite their importance as food for many organisms and their role as environmental indicators, few ecological studies have been conducted in Brazil up to now, and there are no efforts for understanding their role in structuring benthic communities. The aim of the present study is to describe the composition and spatio-temporal distribution of the cumaceans species in the continental shelf offshore of Santos, to investigate the existence and strucuture of ecological communities and the main factors responsible for their functioning, trying to assess the effects of the oceanographic changes upon the community descriptors. The samples were obtained on 21 stations placed in the southeastern continental shelf, between São Sebastião and Peruíbe, in winter 2005 and summer 2006, by means of a 0,09m2 box corer and a rectangular dredge. The results showed the presence of 31 species of cumaceans in the whole area, being 24 in winter and 28 in summer. Higher values of density, diversity and richness obtained in stations near the 50m isobath in both campaigns can may be attributed to the South Atlantic Central Water presence on these areas, since it promotes intense eutrophication of the water column and environmental stability by means of the stablishment of a sub-superficial thermocline. The present study also showed that depth and sediment grain size were the main factors determining the composition and distribution of the cumacean communities. Three zones parallel to the coast with distinct depth ranges and oceanographic features were observed: shallow zone, intermediate zone and deeper zone, each one presenting characteristic species and ecologically structurated in different ways. The use of different sampling gears, as Box corer and dredge, allowed the complementation of data and enlarged the data set adding robustness to the study.

A composição e distribuição de poliquetas foram estudadas na região da plataforma continental sudeste brasileira adjacente à Baixada Santista (Projeto temático ECOSAN), sendo realizadas coletas em 21 estações, durante dois períodos, por meio de um \'box-corer\' (0.09m2). Poliqueta foi o grupo dominante da macrofauna, totalizando 16.274 indivíduos e 214 espécies. A distribuição da fauna relacionou-se com as características do sedimento, como o tamanho médio do grão e seu grau de seleção, ao longo de um gradiente batimétrico, verificando-se a existência de três comunidades distintas: comunidade costeira, situada ao longo da costa em locais de areia muito fina e fina bem selecionadas, dominada por Apoprionospio dayi; comunidade de transição, situada em sedimentosmistos e heterogêneos, entre 50-84m e caracacterizada por Aphelochaeta sp., Levinsenia gracilis e Aricidea (A.) catherinae; comunidade de plataforma externa, situada em sedimentos lamosos profundos, caracterizada por Sigambra grubii, Sternaspis capillata e Leitoscoloplos kerguelensis. Fatores oceanográficos, como hidrodinamismo e intrusão sazonal da ACAS, foram considerados como secundários na estruturação das comunidades. De modo geral, a riqueza e diversidade de poliqueta foram altos, variando de 20 a 66, e de 2,37 a 5,45 respectivamente. A região entre 50-84m apresentou picos desses descritores, provavelmente associados ao sedimento de maior heterogeneidade e à sobreposição de comunidades. Os grupos funcionais apresentaram distribuição semelhante a da composição de espécies. Os consumidores de interface foram dominantes na região costeira, enquanto depositívoros de superfície, e sub-superfície móveis de probóscide lisa, e carnívoros móveis mandibulados, foram dominantes na região entre 50 e 100m. / Composition and distribution of polychaetes were studied in southeastern Brazilian continental shelf adjacent to Santos (ECOSAN Thematic Project). Aiming a spatio-temporal community comprehension, 21 stations were sampled in duplicates during August/2005 and February/2006, with a box-corer (0.09 m2). Polychaete was the dominant macrofauna group, totalizing 16274 individuals and 214 species. The fauna distribution along the depth gradient was related to sediment type, mean grain size and sediment sorting, which partially promoted the existence of three distinct communities: (1) a shallow community, dominated by Apoprionospio dayi, inhabiting very fine and fine well selected sand; (2) a community dominated by Aphelochaeta sp., Levinsenia gracilis and Aricidea (A.) catherinae, inhabiting mixed sediments between 50-84 m depth; (3) and a community dominated by Sigambra grubii, Sternaspis capillata and Leitoscoloplos kerguelensis, inhabiting muddy sediments in a deeper region of the continental shelf. The local hydrodynamic regime and the deep intrusion of the South Atlantic Central Water (SACW) were considered secondary factors in the distribution of polychaetes. High values of richness and diversity were observed throughout the shelf, ranging from 20 to 66, and from 2.37 to 5.45 respectively. The region between 50-84m showed peaks of these community descriptors, probably associated with greater sediment heterogeneity, and the communities overlapping. The functional groups showed a similar distribution to species distribution. Interface-feeders were dominant functional group in coastal region, while motile surface and subsurface deposit feeders with soft proboscis and motile carnivores with jaws were dominant in the region between 50 and 100m.

Opaque oxide minerals (ilmenite, chromite, and magnetite) in sands from the Oregon continental shelf have been studied to establish the provenance, dispersal, and grade of potential shelf placer deposits. The study area extends southward from offshore of the Columbia River in northern Oregon to the Klamath River in northern California.

Sea level and current observations made over the Oregon continental shelf exhibit wavelike characteristics in a frequency band from approximately 0.15 to 0.45 cpd. In a narrow band around 0.22 cpd the current-sea level relationship is consistent with the predicted values for the first mode of Robinson's continental shelf waves. In addition, an interesting relationship exists between the form of the sea level-current coherency spectra and the arrangement of the maximum frequencies for the first three shelf wave modes. The currents were measured in 100 m of water about seven nautical miles off Depoe Bay, Oregon. Current meters were placed at 25, 50 and 75 m depth. The duration of the experiment was from 18 April 1968 until 11 September 1968. Due to some instrument failures a complete current data set for this period was not obtained. Simultaneous and continuous measurements of surface elevation and atmospheric pressure were also obtained at Newport, Oregon, a nearby coastal station. Shelf wave dispersion curves and eigenfunctions for the Oregon coastal profile are computed using a new numerical technique. These are compared with a low frequency (about 0.03 cpd to 0.75 cpd) spectral analysis of the current, sea level and atmospheric pressure records. The relative vertical uniformity of the currents, as a function of frequency, is examined. The longshore component of the current appears to be substantially more barotropic than the onshore-offshore component. / Graduation date: 1972

Coastal low oxygen areas are expanding globally and are predicted to increase in size and duration due to climatic changes associated with a warming ocean. The Gulf of Mexico Hypoxic Zone (GoMHZ) is the second largest regularly occurring hypoxic habitat in the world and has increased in size since it was first mapped in the 1980s. The Mississippi Atchafalaya River System (MARS) floods the Louisiana continental shelf with fresh water high in nitrogenous compounds enhancing primary production which sinks to the sea floor. Stratification that occurs as a result of density differences and coastal currents creates a strong pycnocline that prevents bottom waters from being aerated causing seasonally hypoxic bottom waters (< 2.0 mg L^-1). The Mechanisms Controlling Hypoxia (MCH) project (hypoxia.tamu.edu) made regular cruises during 2004-2005 and 2007-2009 to the GoMHZ performing shelf wide hydrographic surveys and occupying central mooring sites within theoretical zones of differing hypoxic potential. Sediment cores were collected for incubation experiments using Batch Microincubation Chambers (BMICs) to measure rates of sediment community oxygen consumption and nutrient regeneration. Results of incubation experiments characterized sediments as net sources of dissolved inorganic nitrogen, mostly ammonium, and silicate and a net sink of phosphate. Modeling simulations of benthic-pelagic coupling focused in the western study zones related field measurements of benthic nutrient regeneration and primary production to important processes that maintain summertime hypoxia when surface waters are nitrogen limited. After incubations were completed macrofaunal individuals were removed from the cores enumerated and identified to the lowest possible taxon. Macrofauna communities in 2004-2005 were dominated by a hypoxia tolerant community dominated by polychaetes. Hurricanes Katrina and Rita in August and September of 2005 drastically reorganized macrobenthic communities decreasing abundances and negatively impacting diversity. These new communities collapsed under hypoxic stresses potentially impacting the ability of demersal foragers to utilize an important food resource. Large variations in biogeochemical fluxes and patchy distribution of fauna impeded the delineation of significant zones in benthic function and structure.

This thesis addresses the use of potential field data in two main topics: sub-basalt exploration and structure of the deeper crust. Synthetic models and forward models of the Møre margin were constructed to test the sensitivity of the various potential field methods. The synthetic models demonstrate that forward modelling of the gravity and magnetic data is a valuable tool in basement recognition in sub-basaltic settings and the use of gravity gradients further limits the modelling ambiguity and improves the basement mapping. Deep sills, as observed in the Møre Basin, cannot be identified from the gravity and magnetic data alone but the lava flows have a clear effect on the gravity and magnetic signature if thicker than ~1 km. Experiments with Euler Deconvolution reveal the limitations of the method in sub-basaltic settings. A 3D regional gravity and magnetic model of the Møre margin integrated with seismic and well data gives a novel view on the architecture of the continental crust, the distribution of high density lower crust, and the Moho topography. The isostatic response of the water and sediment loading reflected by the Moho provides further insight in the evolution of the margin. The results from the Møre margin model merged with results from a 3D model of the Vøring and Lofoten margins give a regional view on the deep structures on the mid-Norwegian margin. Combination of the modelling results and isostatic considerations provide means to address the origin of the lower crustal body on the margin and the evolution of the whole mid-Norwegian margin.