Submitted by (edna.saturno@ufrpe.br) on 2016-06-21T12:16:19Z No. of bitstreams: 1 Jose Juarez Ferreira Monteiro.pdf: 2239176 bytes, checksum: 5a89e66cf91071885cbfd8673514de7d (MD5) / Made available in DSpace on 2016-06-21T12:16:19Z (GMT). No. of bitstreams: 1 Jose Juarez Ferreira Monteiro.pdf: 2239176 bytes, checksum: 5a89e66cf91071885cbfd8673514de7d (MD5) Previous issue date: 2008-02-26 / The genus Trichodesmium Ehrenberg is very common in the plankton of the tropical and subtropical oceans, and its colonies consist in aggregate filaments which can be seen by naked eye during the flourish period. The genus is composed by 11 species having been the Trichodesmium erythraeum Ehrenberg the only species reported in the continental shelf from Northeast, Brazil sometimes occurring in dense flourishes. This study reports the occurrence of Trichodesmium thiebautii Gomont ex Gomont in tropical waters from the Pernambuco State and it analyzes the spatial and temporal variations in the tricomas density at several points of the platform. Samplings were performed during the rainy period(July, 2005) and dry weather period (November, 2006) at six stations distributed along two profiles perpendiculars to the coast, with distance to the coast of 5, 10 and 20 miles, respectively in the beach of Gaibú (8º18'S and 34º56'W) and in the beach of Serrambi (8º32'S and 35º00'W). The samples for the qualitative and morphological study were collected in superficial drags using 20 μm mesh nets. The samples destined to the quantitative analyses (filament.L-1) were collected with Niskin bottles and the counting accomplished in inverted microscope, using 10 ml sedimentation chambers. Water samples were also collected to identify hydrological variables (temperature, salinity, dissolved oxygen, pH, nitrite,nitrate and phosphate). T. thiebautii was observed during the two annual periods and at the six sampling sites forming colonies in tuft form or rarely bunches, having been observed significant differences in thesize of the cells in relation to the sampling sites and enter the annual periods. However, significant differences were not observed among the tricomas of a same colony. The density of the filaments presented minimum values at sites near the coast (5 miles) and higher values at more distant sites (20 miles) during the dry weather period. Hydrological variables presented short variations noting subtle differences between the surface and bottom, contributing for a wide species distribution along the study area. The registration of T. thiebautii in the continental shelf of Pernambuco enlarges the speciesdistribution for the Brazilian Northeast region. / O gênero Trichodesmium Ehrenberg é muito comum no plâncton dos oceanos tropicais e subtropicais, e suas colônias consistem em filamentos agregados que podem ser vistos macroscopicamente durante o período de floração. O gênero é composto por 11 espécies entre as quais apenas Trichodesmium erythraeum Ehrenberg havia sido assinalada na plataforma continental do Nordeste do Brasil, às vezes ocorrendo em densas florações. Este estudo relata a ocorrência de Trichodesmium thiebautii Gomont ex Gomont em águas tropicais do estado de Pernambuco e analisa as variações espaciais e temporais da densidade dos tricomas em vários pontos da plataforma. As coletas foram realizadas durante o período chuvoso (julho de 2005) e período de estiagem (novembro de 2006), em seis pontos distribuídos ao longo de dois perfis perpendiculares à costa, com distância à costa de 5, 10 e 20 milhas,respectivamente na praia de Gaibú (8º18'S e 34º56'W) e na praia de Serrambi (8º32'S e 35º00'W). As amostras para o estudo qualitativo e morfológico foram coletadas em arrastos superficiais com redes de malha de 20 μm de abertura. As amostras destinadas às análises quantitativas (filamento.L-1) foram coletadas com garrafas de Niskin e as contagens realizadas em microscópio invertido, utilizando-se câmaras de sedimentação de 10 mL. Foram também coletadas amostras de água para análises das variáveis hidrológicas (temperatura, salinidade, oxigênio dissolvido, pH, amônia, nitrito, nitrato e fosfato). T. thiebautii foi encontrada durante os dois períodos anuais e nos seis pontos de coleta, formando colônias em forma de tufos ou raramente em feixes, tendo sido observadas diferenças significativas no tamanho das células em relação aos pontos de coleta e entre os períodos anuais. Entretanto, diferenças significativas não foram observadas entre os tricomas de uma mesma colônia. A densidade dos filamentos apresentou valores mínimos em locais próximos à costa (5 milhas) e valores maiores em locais mais afastados (20 milhas), durante o período de estiagem. As variáveis hidrológicas apresentaram pequenas variações, notando-se pequenas diferenças entre a superfície e o fundo,contribuindo para uma ampla distribuição da espécie ao longo da área pesquisada. O registro de T.thiebautii na plataforma continental de Pernambuco amplia a distribuição da espécie para a região Nordeste brasileira.

Des épisodes à Dinophysis affectent périodiquement l'exploitation des fruits de mer dans le Bassin d'Arcachon. Le réseau de surveillance interne au Bassin d'Arcachon montre que Dinophysis est advecté de l'océan ouvert. Le but de cette étude est de déterminer l'origine de Dinophysis. Des campagnes en mer sur le plateau continental Aquitain ont permis d'identifier une zone propice au développement de Dinophysis au large de Capbreton. Les épisodes à Dinophysis dans le bassin d'Arcachon se produisent suite à des vents d'Ouest qui induisent des courants vers le Sud d'après la littérature. L'étude des données hydrodynamiques acquises pendant les campagnes met en évidence un processus complexe et nouveau suite aux vents d'Ouest: de forts courants le long de la côte vers le Nord capables de transporter Dinophysis de Capbreton jusqu'au Bassin d'Arcachon. Un travail de modélisation a permis de reproduire ce courant et d'étudier son mécanisme particulier lié coin Sud-Est du Golfe de Gascogne. / Abstract

[pt] Estudos paleoambientais sobre reconstruções climáticas no pretérito ajudam a compreender os processos biogeoquímicos atuais e, portanto, fornecem subsídios ao atual cenário de mudanças globais. As principais ferramentas utilizadas nesses estudos envolvem indicadores que requerem a integração de informações geoquímicas, geomorfológicas, oceanográficas e biológicas. No presente trabalho, dois testemunhos (RJ13-01 e RJ13-02) foram coletados na plataforma continental do Rio de Janeiro na isóbata de 100-m e datados através dos métodos de 210Pb e 14C, englobando, respectivamente, 14,5 cal kyr BP e 5,3 cal kyr BP. O objetivo principal do trabalho foi investigar o efeito de variáveis climáticas e ambientais sobre o aporte de material autóctono e alóctono na plataforma continental do Rio de Janeiro. Foram considerados dados geofísicos, granulometria, elementos traços (V, Cr, Mn, Ni, Cu, Zn, As, Sr, Ag, Cd, Sn, Ba, Tl, Pb e U), elementos majoritários (Ca, Si, Al e Fe), nitrogênio total (TN), carbono orgânico total (TOC), carbonato de cálcio (CaCO3), hidrocarbonetos alifáticos (n-alcanos) e hidrocarbonetos aromáticos (HPAs), assim como consideradas razões entre elementos e compostos que indicam a introdução de material continental e biogênico, razões redox e de produtividade, além de marcadores de tipo de vegetação e de combustão. Os resultados ressaltaram três fases deposicionais na área estudada: a primeira fase vai de 14,5 cal kyr BP à 7,5 cal kyr BP, e se caracteriza pela ocorrência de granulometria média a grosseira, fragmentos de conchas, alto teor de Si (27 porcento), alto aporte de material biogênico Ca/Al (3,00), altos valores (30,5) de ACL (tamanho médio da cadeia n-alcanos) e alta contribuição de HPAs pirogênicos (33 porcento), por volta de 8,0 cal kyr BP, indicando maior incidência de clima seco na maioria dos períodos, além de ser marcada por níveis do mar mais baixos. A segunda fase, entre 7,5 cal kyr BP e 4,5 cal kyr BP, mostrou influência das Águas Centrais do Atlântico Sul (SACW), marcada por um máximo de elevação do nível do mar, eventos de seca com maior intensidade de incêndios naturais com alta contribuição de HPAs pirogênicos de 5-6 anéis (68 porcento), entre 6,1 cal kyr BP e 4,1 cal kyr BP, e alto aporte de material continental Al/Ca (0,69); Fe/Ca (0,27) e alta produtividade. A terceira fase cobre o Holoceno superior, a partir de 4,5 cal kyr BP até o presente. Nessa fase, foram encontrados fluxos mais elevados de matéria orgânica, entre 3,2 cal kyr BP a 3,3 cal kyr BP (RJ13-01) e 3,4 cal kyr BP (RJ13-02), como indicado por TN, TOC, Ni, Cu, Zn, HA e HPAs, e um maior aporte continental, devido aos altos valores de razões redox-sensíveis a partir de 2,5 cal kyr BP no RJ13-01 e ao longo do testemunho RJ13-02. Esses fatores provavelmente são decorrentes do deslocamento da Zona de Convergência Intertropical (ITCZ) mais ao sul, deixando o clima mais úmido na Amazônia, a intensificação do SAMS trazendo umidade para SE do país através da SACZ. Porém, também podem refletir um evento de menor nível do mar, que influenciou nos níveis de oxigênio na coluna d água. Por outro lado, indicadores de clima seco (ACL, HPAs pirogênicos de 5-6 anéis) sugerem que houve oscilações entre clima úmido e seco ao longo do Holoceno superior. Desta forma, os indicadores orgânicos e inorgânicos considerados nos testemunhos da plataforma continental do RJ possibilitaram avaliar e corroborar dados de outros estudos sobre os eventos climáticos ocorridos nos últimos 14 mil anos no SE do Brasil, e suas relações com fatores como: variações no nível do mar, mudanças na ITCZ, intensificação da SAMS influenciando a SACZ, mudanças nos padrões de ventos e na Corrente do Brasil; influência da SACW mais no sentido S-W do sistema de ressurgência de Cabo Frio; variações climáticas com registros de incêndios naturais e variações da vegetação; além de registros que podem ser relacionados à ocupação humana. / [en] Paleoenvironmental studies on climate reconstructions in the past help to understand the current biogeochemical processes and therefore become increasingly important in the current scenario of global changes. The main parameters used in these studies involve proxies that require the integration of geochemical, geomorphological, oceanographic and biological information. In this study two cores (RJ13-01 and RJ13-02) were collected on the continental shelf of Rio de Janeiro in the isobath 100-m and dated by 210Pb and 14C methods covering14.5 cal kyr BP and 5.3 cal kyr BP, respectively. The main goal of this work was to investigate the effect of climatic and environmental variables on the autochthonous and allochthonous material inputs in the continental shelf of Rio de Janeiro. For this, geophysical properties, grain size, trace elements (V, Cr, Mn, Ni, Cu, Zn, As, Sr, Ag, Cd, Sn, Ba, Tl, Pb and U), major elements (Ca, Si, Al and Fe), total nitrogen (TN), total organic carbon (TOC), calcium carbonate (CaCO3), aliphatic hydrocarbons (n-alkanes) and polycyclic aromatic hydrocarbons (PAHs) were considered jointly with continental and biogenic input proxies, redoxsensitive and productivity proxies besides vegetation type and combustion proxies. Results highlighted three periods: the first period (from 14.5 to 7.5 cal kyr BP) with the occurrence of mean grain size of the sediment, shell fragments, high content of Si (27 percent), high input of biogenic material Ca/Al (3.00) and high ACL (average chain length) values (30.5). In addition to high contribution of pyrogenic PAHs (33 percent) around 8.0 cal kyr BP indicating higher incidence of dry weather in most periods; marked by a low sea level. The second period between 7.5 cal kyr BP and 4.5 cal kyr BP showed the influence of the South Atlantic Central Waters (SACW) marked by a maximum transgression of the sea, drought events with greater intensity of wildfires with high contribution of pyrogenic PAHs of 5-6 rings (68 percent) between 6.1 and 4.1 cal BP kyr BP and high input continental materials Al/Ca (0.69); Fe/Ca (0.27) and high productivity. The third period covers the late Holocene from 4.5 cal kyr BP to present. In this period, higher fluxes of organic matter were found between 3.2 cal kyr BP to 3.3 cal kyr BP (RJ13-01) and 3.4 cal kyr BP (RJ13-02), as indicated by TN, TOC, Ni, Cu,Zn, n-alkanes and PAHs, and higher continental input due to high redox-sensitive proxies from 2.5 cal kyr BP in RJ13-01 and along RJ13-02. These factors are probably related to the displacement further south of the Intertropical Convergence Zone (ITCZ), which brought humidity to Amazon, the intensification of SAMS bringing humidity to SE of Brazil trought SACZ. Also has been marked by the decrease in sea level which influenced the oxygen levels in the water column. On the other hand, dry climate indicators (ACL, pyrogenic PAHs with high molecular weight) suggest that there were fluctuations between wet and dry climate along the late Holocene. Thus, the organic and inorganic proxies considered on the cores of continental shelf of Rio de Janeiro allowed to evaluate and corroborate the data of other studies of climate events over the past 14,000 years in SE Brazil and their relation to the facts such is the variations in the sea-level, chances in ITCZ, the intensification of SAMS and SACZ, changes in wind pattern, and in the Brazilian current; influence of the SACW further S-W of the Cabo Frio upwelling system; and climate variations with records of wildfires and variation on the vegetation; in addition to records that could be related to human occupation.

Submarine canyons incising the continental shelf and slope are hot spots for topography-internal wave interactions, with elevated dissipation and mixing contributing to regional transport and biological productivity. At two Barkley Canyon sites (the continental slope below the shelf-break, and deep within the canyon), four overlapping years of horizontal velocity time-series data are used to examine the effects of irregular topography on the internal wave field. Mean currents are topographically guided at both sites, and in the canyon there is an inter-annually consistent, periodic (about a week) up-canyon flow (-700 to -900 m) above a near-bottom down-canyon layer. There is elevation of internal wave energy near topography, up to a factor of 10, 130 m above the slope, and up to a factor of 100, 230 m above the canyon bottom. All bands display weak inter-annual variability, but significant seasonality. Sub-diurnal and diurnal flows are presumably sub-inertially trapped along topography, and the diurnal band appears to be forced locally (barotropically). Both sites have high near-inertial energy. At the slope site, near-inertial energy is attenuated with depth, while in the canyon it is amplified near the bottom. Both sites show intermittent near-inertial forcing associated with wind events, downward propagation of high-mode internal waves, and the seasonal mixed-layer depth, though fewer events are observed in the canyon. Free semidiurnal internal tides are focused and reflected near critical shelf-break and canyon floor topography, and appear to experience both local and remote (baroclinic) forcing. The high-frequency internal wave continuum has enhanced energy near bottom at both sites (up to 7 times the open-ocean Garrett-Munk spectrum), and inferred dissipation rates increasing from a background of less than 10^-9 W kg^-1 and reaching 10^-7 W kg^-1 near topography. Dissipation is most strongly correlated with the semidiurnal (M2) constituent at both sites, with secondary contributions from the sub-diurnal (Sub_K1) band on the slope, and the near-inertial (NI) band in the canyon. Power laws for these dependencies are dissipation ~ M2^0.83 + Sub_K1^0.59 at the slope, and dissipation ~ M2^1.47 + NI^0.24 in the canyon. There is evidence in spectra of a near-buoyancy frequency build-up of energy correlated with high-frequency continuum variability, with a power law fit of 'shoulder' power ~ dissipation^0.34 that is independent of site topography. Though some general results are expected from observations at other slope and canyon sites, the greater temporal extent of these data provide a uniquely long-term evaluation of such processes. / Graduate

Coastal ecosystems continue to face numerous negative impacts from human activities ranging from local nutrient enrichment to global warming. These threats have complex effects on coastal biogeochemistry, which in turn alters ecosystem ecology and climate. While sediments have long been recognized as cornerstones of marine ecosystem functioning, the impacts of anthropogenic change on benthic biogeochemical cycling remain challenging to constrain. This knowledge gap stems from technological issues as measuring marine sediment processes under natural conditions is a formidable challenge. To help move the field of sediment biogeochemistry forward, I developed a novel mass spectrometer-based system and used it to quantify dissolved gas fluxes from marine sediments. In Chapter One, I survey the field of underwater mass spectrometry from its inception three decades ago to the present. Through comprehensive descriptions of the current status of the technology, field applications to date, and future trends, I provided guidance for how to leverage this powerful new tool to measure gaseous compounds in the under sampled ocean. In Chapter Two, I review the role of permeable shelf sediments in marine nitrogen cycling. My synthesis of the small but growing body of work on nitrogen cycling in shelf sands exposed conflicting evidence surrounding the nitrogen removal capacity of permeable sediments, and I proposed targeted approaches, such as the development of noninvasive in situ technologies, to resolve these controversies. In Chapter Three, I present a newly developed flow-injection sampling system that can be coupled to a mass spectrometer to measure a range of dissolved gas species in the pore water of highly permeable sandy sediments. Rigorous calibration and validation experiments demonstrate that this novel system can quantify dissolved gas depth profiles, as well as fluxes across the sediment-water interface, in permeable sediments. Furthermore, with my prescribed design improvements, this tool promises to provide in situ data in dynamic sandy environments. In Chapter Four, I used the flow-injection mass spectrometer system to measure benthic fluxes of gaseous nitrogen and methane from cohesive sediments subjected to low oxygen conditions and varying organic matter loads. The unprecedented high temporal resolution of the gas flux data revealed the complex and dynamic effects of changing environmental conditions on the capacity of sediments to remove reactive nitrogen and regulate methane emissions. / 2024-11-08T00:00:00Z

Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Earth and Planetary Science, 1981. / Microfiche copy available in Archives and Science. / Vita. / Bibliography: leaves 95-96. / by Peter Reid Daifuku. / M.S.

Coastal water quality is intricately linked to environmental factors, particularly meteorological and hydrological conditions. Weather conditions determine wind speed and direction, which in turn influence coastal currents, and these currents play a critical role in the transport and variability of water quality parameters. Understanding how these dynamic interactions impact water quality is essential for the effective management and preservation of coastal ecosystems. This dissertation investigates the effects of varying flow conditions on key water quality parameters in the Louisiana Continental Shelf, utilizing data from two research cruises. The study specifically focuses on how concentration variability and transport mechanisms of water quality indicators respond to different environmental conditions, including the passage of cold fronts and periods of non-frontal conditions. In this research, data were collected using a conductivity-temperature-depth (CTD) system and through the analysis of water samples to assess changes in nutrient concentrations, dissolved oxygen levels, chlorophyll-a, and Colored Dissolved Organic Matter (CDOM). These samples were collected under two distinct environmental conditions: following a cold front and during non-frontal conditions. Analytical methods were used to quantify the water quality parameters, while hydrodynamic modeling was applied to assess the transport and dispersion patterns of these indicators. The results show that cold fronts increase nutrient concentrations and decrease dissolved oxygen levels due to enhanced mixing and upwelling. The cold front activity also promotes southwestward transport of water quality parameters, driven by the region's hydrodynamic forces. Under stable weather conditions, nutrient and chlorophyll-a concentrations increase, but transport is limited, with reduced dispersion resulting from weaker hydrodynamic forces. CDOM component analysis revealed that cold front conditions lower CDOM concentrations and improve light penetration, while non-frontal conditions elevate CDOM concentrations, reducing light penetration and impacting aquatic ecosystem productivity. These findings enhance our understanding of how meteorological events, hydrological conditions, and water quality interact in coastal regions. The research demonstrates how weather conditions distinctly influence nutrient dynamics and CDOM behavior. These insights are crucial for developing effective water quality management strategies for the Louisiana Continental Shelf and similar coastal regions worldwide, supporting global efforts to mitigate challenges posed by climate change and human activity in coastal ecosystems.

Zooplankton assemblages were examined from waters off the west coast of Scotland encompassing the Firths of Lorn and Clyde, the North Channel, and the Malin Shelf. Size fractionated samples (coarse, >1000μm; medium, 1000μm-330μm; fine, 330μm-180μm) were collected with a submersible pump from 10m and 30m depth in March (1987) and May (1986) providing a composite picture of the fauna in early and late spring conditions, respectively. The feasibility of using image analysis as a method for processing zooplankton samples was examined. Although a programme was successfully operated to obtain individual measurement data, much work is still required before a fully automated programme for routine use by planktologists is available. Total zooplankton numbers and biomass, and species distributions and relative abundances were examined. Species assemblages were identified using multivariate analyses. Biomass and abundance spectra by size were examined for the major station groupings. In general, meroplankton dominated the fauna in the Firth of Lorn while large numbers of Calanus spp. occurred in the Firth of Clyde. Small copepods such as Oithona spp. were characteristic of the assemblage on the Malin Shelf. Salinity, followed by temperature, showed the strongest association with the observed station clusters. Chlorophyll a and depth did not generally appear to influence station groupings. The potential for the mixing and exchange of zooplankton between the regions of the study area was evaluated. The results suggest that zooplankton may be entrained from the Firth of Clyde by the Scottish Coastal Current during the spring period. The Malin Shelf may also be an important source of zooplankton for the Firth of Lorn during winter months when an onshore flow of Atlantic water occurs.

A dinâmica sedimentar sobre um trecho da plataforma continental leste brasileira foi analisada através da abordagem combinada entre a análise do clima de ondas (WAVEWATCH III), modelagem da propagação das ondas para águas rasas (MIKE 21 SW) e aplicação de equações que estimam o transporte de partículas em função da tensão de cisalhamento causada pelas ondas sobre o fundo marinho. Assim, baseado no clima de ondas da região, são estimados os potenciais de mobilidade sedimentar como resposta a diversas condições forçantes. O clima de ondas em frente a Ilhéus é caracterizado pela predominância de ondas do quadrante leste (60%), com 20% provenientes de sudeste e 15% de sul. Em frente a Caravelas, o espectro de ondas é caracterizado por 40% de ondas de leste, 15% do quadrante sudeste e 35% provenientes de sul. O clima de ondas é influenciado pelas descontinuidades na largura da plataforma continental nesse trecho da costa, atenuando a influência das ondas de swell provenientes do quadrante sul em frente a Ilhéus. Os resultados indicam mobilidade sedimentar até 50 m de profundidade na plataforma de Ilhéus e até 20 m na plataforma de Abrolhos ao longo do ano, no entanto, eventos esporádicos mais energéticos são capazes de mobilizar sedimentos até cerca de 200 m de profundidade na plataforma de Ilhéus e até 100 m na plataforma de Caravelas. A mobilidade de partículas de maiores dimensões, como os rodolitos da plataforma de Abrolhos, maior campo de rodolitos conhecido do mundo, foi analisada através do parâmetro de Shields, que leva em consideração tamanho e densidade das partículas. Os resultados indicam que a mobilidade dos rodolitos de Abrolhos está principalmente condicionada pela ocorrência de eventos mais energéticos, especialmente no outono. As regiões com maior mobilidade são a porção norte, próxima a quebra da plataforma e a porção centro-sul da plataforma, ambas com profundidades entre 20 e 40 m. O detalhamento do conhecimento sobre o transporte de sedimentos na plataforma continental leste brasileira contribui para o entendimento na dinâmica sedimentar na região. A morfologia complexa da plataforma, combinada com o clima de ondas incidente, são fatores fundamentais no potencial de mobilização de sedimentos. / The sedimentary dynamics on a stretch of the Brazilian continental shelf was analyzed through a combined approach between wave climate analysis (WAVEWATCH III), shallow water wave propagation modeling (MIKE 21 SW) and equations estimating the transport of particles as a function of bed shear stress by the waves. Thus, based on the wave climate of the region, sediment mobility potentials are estimated in response to several forcing conditions. Wave climate is characterized by the predominance of east waves in front of Ilhéus (60%), 20% from southeast quadrant and 15% from south. In front of Caravelas a wave spectrum is characterized by 40% from east quadrant, 15% from southeast and 35% from south. Continental shelf width discontinuity influences wave climate at Ilhéus, attenuating waves from south quadrant. The results indicate sediment mobility up to 50 m depth on the Ilhéus shelf and up to 20 m on the Abrolhos shelf along the entire year; however, more sporadic energetic events are able to mobilize sediments up to 200 m depth on the Ilhéus shelf and up to 100 m on the Caravelas shelf. Larger particle mobility, such as the rhodoliths of the Abrolhos shelf, the largest known rhodolite field in the world, was analyzed using the Shields parameter, which takes into account particle size and density. The results indicate that the mobility of Abrolhos rhodolites is mainly conditioned by the occurrence of more energetic events, especially in autumn. The regions with the greatest mobility are the northern portion, near the shelf break and the center-south portion of the shelf, both with depths between 20 and 40 m. The detailed knowledge on sediment transport in the Brazilian continental shelf contributes to the understanding of sedimentary dynamics in the region. The complex morphology of the continental shelf, combined with the incident wave climate, are fundamental factors in sediment mobilization potential.

O presente trabalho teve como objetivo verificar a estrutura espacial e vertical da população de anelídeos Polychaeta da Baía de Santos e plataforma continental adjacente, através do estudo integrado das características físico-químicas, sedimentológicas, concentração de compostos químicos e elementos metálicos. Paralelamente, procurou-se determinar a origem da matéria orgânica sedimentar através dos teores de C/N/S e dos marcadores orgânicos geoquímicos com o intuito de identificar uma possível influência do complexo estuarino de Santos sobre a plataforma adjacente à baía. A área de estudo localiza-se no litoral do estado de São Paulo e é influenciada por atividades industrial e portuária, além de receber o esgoto das cidades de Santos e São Vicente. Entre 2004 e 2005 foram realizadas 4 campanhas na baía para amostrar 8 estações, enquanto 6 pontos foram amostrados na plataforma adjacente no inverno/2005 e verão/2006. Os parâmetros físicos e a concentração de oxigênio e nutrientes dissolvidos foram mensurados em todas as estações. As amostras de sedimento para o estudo dos poliquetas, análises granulométricas, teores de carbono orgânico e nitrogênio e enxofre totais, concentração de esteróis fecais, hidrocarbonetos alifáticos (n-alcanos e LABs) e aromáticos (HPAs), pesticidas organoclorados (PCBs) e metais foram obtidas com boxcorer de 0,09m2 de área. Os sedimentos finos predominaram na porção central da Baía de Santos e na faixa de transição entre a desembocadura da baía e a plataforma adjacente, responsáveis pela maior retenção dos metais Pb, Zn e Cr, hidrocarbonetos n-alcanos, HPAs, LABs, de PCBs e esteróis fecais advindos do efluente urbano, dragagem do Canal do Porto e da contribuição atmosférica. Em conseqüência, observou-se aí os menores valores de densidade, riqueza, diversidade e equitatividade, com dominância de Mediomastus capensis, Prionospio sp. e Aricidea cf. catharinae. Tais espécies foram as mais abundantes em ambas as áreas, revelando seu comportamento de oportunistas e tolerantes, e atuando como bioindicadores de um ambiente sob alterações físicas e químicas. As razões C/N e os marcadores orgânicos geoquímicos mostraram que a matéria orgânica que adentra a Baía de Santos é essencialmente terrígena, enquanto na plataforma continental adjacente observou-se contribuições alóctones, provenientes principalmente do fito- e zooplâncton oceânico. Tais resultados sugerem não haver influência direta do material exportado pelo complexo estuarino da Baixada Santista, quer orgânico ou inorgânico, sobre o ambiente de plataforma adjacente. / The aim of the present work was to verify the spacial and vertical Polychaeta distribution in sediment samples of Santos Bay and adjacent continental shelf by analyzing physicochemical characteristics, granulometric pattern, chemical compounds concentration and metallic elements. Parallely, it looked for determining the organic matter origin by C/N/S content and geochemical organic biomarkers to identify a possible influence of Santos estuarine complex on adjacent continental shelf. The area of study is located on the SE Brazilian coastline, São Paulo, close to the largest commercial harbour and industrial centre in South America, besides receiving considerable amount of urban sewage from Santos and São Vicente cities. Between 2004/2005 sediment samples were taken at 8 plots during 4 oceanographic surveys, whereas 6 plots were sampled on continental shelf in the Winter/2005 and Summer/2006. Physical parameters, dissolved oxygen and nutrient concentrations were measured at all stations. Sediment samples for biological study and granulometry, besides organic carbon content, total nitrogen, total sulphur, faecal sterols and biomarkers hydrocarbons (aliphatic, aromatic, LABs), organochlorinateds (PCBs) and metals were collected with a 0,09m2 box-corer. The results pointed out that fine sediments predominated in both central region of Santos bay and near the transition area between bay mouth and adjacent shelf, being responsible for the high content of metal (Pb, Zn, Cr), hydrocarbons, PCBs and faecal sterols provenient of the urban discharge, dredging activities in the harbour channel and atmosphere contribution. Consequently, density, species richness, diversity and evenness were low with dominance of Mediomastus capensis, Prionospio sp. and Aricidea cf. catharinae. These species were abundant in both areas revealing their opportunistic and tolerant behaviour, and its role as bioindicators of environments under chemical and physical changes. The C/N ratios and organic geochemical biomarkers showed that the organic matter deposited in Santos bay is essentially terrigenous, while on continental shelf the contribution comes from the open ocean as fito- and zooplankton. The data also suggest that there is no direct influence of material, organic or not, exported by the estuarine complex to the adjacent continental shelf environment.