A qualidade da matéria orgânica e a magnitude de suas deposições estão entre os principais fatores que controlam as respostas dos organismos bênticos marinhos. Uma vez depositada nos sedimentos, a matéria orgânica é degradada por processos biogeoquímicos microbianos, que podem ser acelerados mediante a bioturbação da macrofauna. Entretanto, em regiões costeiras, a dinâmica das forçantes ambientais influencia tanto a qualidade dos recursos alimentares, quanto os mecanismos de utilização pelos organismos, implicando em alterações na remineralização da matéria orgânica. Este estudo visou investigar o sistema bêntico da área costeira de Ubatuba frente às variações da qualidade e quantidade da matéria orgânica, incluindo os impactos da bioturbação na diagênese recente e regeneração de nutrientes. Observou-se que os processos físicos da região atuaram na variação da qualidade da matéria orgânica e na estruturação dos organismos bênticos. Os microorganismos exploraram matéria orgânica de diferentes composições, exercendo também importante papel para a comunidade macrobêntica, enriquecendo os detritos orgânicos disponíveis como alimento. A meiofauna não apresentou relação direta com alta qualidade da matéria orgânica, já a macrofauna foi estruturalmente modificada pela passagem de frentes frias e pela presença de compostos lábeis, quando os mesmos apareceram em maiores concentrações. Experimentalmente, verificou-se que a mistura de partículas foi significativa somente quando altas densidades da macrofauna estiveram presentes na superfície do sedimento. Além disso, foi demonstrado em laboratório que a macrofauna exerceu pouca influência nos fluxos de oxigênio e nutrientes do sedimento para a água, porém suficiente para estimular a decomposição de material orgânico verticalmente na coluna sedimentar. Portanto, a dinâmica dos processos físicos e as variações estruturais da macrofauna são importantes fatores ecológicos na modulação de funções fundamentais do ecossistema costeiro de Ubatuba, como produtividade, metabolismo bêntico, degradação da matéria orgânica e fluxos de energia. / The magnitude and quality of organic matter inputs to the seafloor are among the main factors regulating the responses of marine benthic communities. Once deposited on the sediments, the organic matter is degraded by several microbial biogeochemical processes that may be stimulated through macrofauna bioturbation. However, in coastal regions the dynamics of environmental forcing not only influences the quality of food sources, but the food uptake by organisms, resulting in changes on remineralization rates of organic material. This study aimed to investigate the benthic system of Ubatuba coastal area in relation to quality and quantity of organic matter as well as bioturbation impacts on early diagenesis and nutrient regeneration. Data suggests that physical stresses influenced the quality of organic matter and the structure of benthic organisms. Different compositions of organic matter were assimilated by microorganisms, which in turn played an important role to the macrobenthic community, enriching the organic detritus available as food. The meiofaunal organisms did not numerically respond to the deposition of high quality organic matter, while macrofauna community structure was modified by the incidence of cold fronts and by the presence of labile compounds, whenever available. Experimentally, sediment reworking was only significant at higher levels of macrofaunal density on the sediment surface. In addition, it was demonstrated in laboratory that macrofauna imposed weak effects on the fluxes of oxygen and nutrients from sediments to the water column, but those changes were enough to stimulate vertically in the sediments, the decomposition of organic matter. Therefore, the dynamics of physical processes and the variability on macrofaunal structure are both important ecological factors modulating fundamental functions of the coastal ecosystem in Ubatuba, including productivity, benthic metabolism, degradation of organic matter and energy flow.

Beach grain size plays a major role in controlling beach slope and sediment transport rates and is a crucial criterion in selecting the appropriate fill material for beach nourishment. Yet, little is known about how and why beach grain size (and sorting) varies both spatially and temporally on high-energy sandy beaches. Therefore, in this PhD research project, the presence, magnitude and predictability of any spatio-temporal sediment variability was investigated on a number of contrasting high-energy (average significant wave height = 0.8 to 3.5 m), predominantly macrotidal (MSR = 3.1 – 6.2 m), sandy (0.26 – 0.64 mm) beach sites around the southwest peninsula of the United Kingdom (UK). The spatial extent of the data collected ranges from regional (one off snapshot of the sediment conditions on 53 beaches over 485 km of coastline) to local scales (repeated high-resolution samples from across the inter- and subtidal zone of a single high-energy sandy beach; Perranporth, UK). The temporal scales of the sampling ranges from tidal scale (~12 hours) up to monthly (long-term monitoring since 2008). A combination of traditional and modern field data collection methods has provided new insights into the sediment dynamics of sandy beaches. Surface and 0.25 m core sediment samples from the 53 beaches around the southwest UK and high-resolution digital measurements with longer 1 m sand cores from the intertidal zone, plus grab samples from the subtidal zone, at Perranporth, indicated the presence of three quasi-permanent spatial trends. On all sandy beaches, surface sediments became coarser (and better sorted) in the seaward direction across the intertidal zone. Peak sediment sizes were observed on the lower beach around mean low water springs, which were an average 19% coarser (and 8% better sorted) than sediments sampled on the upper intertidal beach. Sediment size (and sorting) also increased (improved) with distance down the sediment column over the top 0.25 m to 1 m. Peak sediment sizes at depth were an average 16% coarser (and 16% better sorted) than surface sediments. In the subtidal zone, surface sediments became finer and poorer sorted with increasing offshore distance. Minimum sediment size occurred on the subtidal bar crest and were an average 21% finer (and 51% poorer sorted) than the lower beach sediments and 5% finer (and 38% poorer sorted) than upper beach sediments. The coarsest sediments were usually the best sorted at all locations. The intertidal coarsening was deterministically linked to the location and amount of breaking wave-induced turbulence. The peak sediment sizes (and sorting) on the lower beach correlated with the location of peak wave dissipation (sediment size to amount of wave dissipation, r2 = 0.86) and the finer sediment sizes on the upper beach and bar were coincident with reduced amounts of wave dissipation in these regions. Long-term seasonal monitoring of the surface sediments at Perranporth indicated a background seasonality, where the winter months were an average 35% coarser and 22% better sorted than samples collected in summer. This seasonal pattern was punctuated by episodic storm events that promoted a significant coarsening (up to 112% in the extreme winter storms of 2014) of the surface sediments and significant beach erosion up to 175 m3/m. An empirical model forced by the degree of disequilibrium between an instantaneous and antecedent (weighted average) wave steepness time series was able to capture up to 86% of the sediment grain size and sorting variability, incorporating both the seasonal and storm driven change. The same model, applied to daily observations of sediment size and sorting changes was able to explain 72% of the variability. A conceptual model is proposed that extends the cross-shore sediment transport shape functions to include the various sediment (size and sorting) responses alongside the morphodynamic evolution during persistently high and low wave steepness conditions. Under high steepness waves, the finer material is preferentially removed from the lower intertidal beach, leaving behind coasrer sediments. This fine material is transported to the subtidal bar, which becomes finer (and more poorly sorted) inversely with the coarsening (and improved sorting) of the intertidal zone sediments. Under low steepness waves, this fine material is returned from the bar to the intertidal beach. This work provides a detailed, quantitative insight into the magnitude of sediment grain size and sorting changes exhibited by sandy beaches on a number of spatial and temporal scales. Several consistent trends were observed on a range of sandy beaches despite their different environmental conditions and geological histories. This improved understanding of sediment grain size and sorting changes on beaches will hopefully aid future research efforts and ensure that this fundamental aspect of coastal science is not overlooked or oversimplified.

A qualidade da matéria orgânica e a magnitude de suas deposições estão entre os principais fatores que controlam as respostas dos organismos bênticos marinhos. Uma vez depositada nos sedimentos, a matéria orgânica é degradada por processos biogeoquímicos microbianos, que podem ser acelerados mediante a bioturbação da macrofauna. Entretanto, em regiões costeiras, a dinâmica das forçantes ambientais influencia tanto a qualidade dos recursos alimentares, quanto os mecanismos de utilização pelos organismos, implicando em alterações na remineralização da matéria orgânica. Este estudo visou investigar o sistema bêntico da área costeira de Ubatuba frente às variações da qualidade e quantidade da matéria orgânica, incluindo os impactos da bioturbação na diagênese recente e regeneração de nutrientes. Observou-se que os processos físicos da região atuaram na variação da qualidade da matéria orgânica e na estruturação dos organismos bênticos. Os microorganismos exploraram matéria orgânica de diferentes composições, exercendo também importante papel para a comunidade macrobêntica, enriquecendo os detritos orgânicos disponíveis como alimento. A meiofauna não apresentou relação direta com alta qualidade da matéria orgânica, já a macrofauna foi estruturalmente modificada pela passagem de frentes frias e pela presença de compostos lábeis, quando os mesmos apareceram em maiores concentrações. Experimentalmente, verificou-se que a mistura de partículas foi significativa somente quando altas densidades da macrofauna estiveram presentes na superfície do sedimento. Além disso, foi demonstrado em laboratório que a macrofauna exerceu pouca influência nos fluxos de oxigênio e nutrientes do sedimento para a água, porém suficiente para estimular a decomposição de material orgânico verticalmente na coluna sedimentar. Portanto, a dinâmica dos processos físicos e as variações estruturais da macrofauna são importantes fatores ecológicos na modulação de funções fundamentais do ecossistema costeiro de Ubatuba, como produtividade, metabolismo bêntico, degradação da matéria orgânica e fluxos de energia. / The magnitude and quality of organic matter inputs to the seafloor are among the main factors regulating the responses of marine benthic communities. Once deposited on the sediments, the organic matter is degraded by several microbial biogeochemical processes that may be stimulated through macrofauna bioturbation. However, in coastal regions the dynamics of environmental forcing not only influences the quality of food sources, but the food uptake by organisms, resulting in changes on remineralization rates of organic material. This study aimed to investigate the benthic system of Ubatuba coastal area in relation to quality and quantity of organic matter as well as bioturbation impacts on early diagenesis and nutrient regeneration. Data suggests that physical stresses influenced the quality of organic matter and the structure of benthic organisms. Different compositions of organic matter were assimilated by microorganisms, which in turn played an important role to the macrobenthic community, enriching the organic detritus available as food. The meiofaunal organisms did not numerically respond to the deposition of high quality organic matter, while macrofauna community structure was modified by the incidence of cold fronts and by the presence of labile compounds, whenever available. Experimentally, sediment reworking was only significant at higher levels of macrofaunal density on the sediment surface. In addition, it was demonstrated in laboratory that macrofauna imposed weak effects on the fluxes of oxygen and nutrients from sediments to the water column, but those changes were enough to stimulate vertically in the sediments, the decomposition of organic matter. Therefore, the dynamics of physical processes and the variability on macrofaunal structure are both important ecological factors modulating fundamental functions of the coastal ecosystem in Ubatuba, including productivity, benthic metabolism, degradation of organic matter and energy flow.

In 2008 and 2010, exotic drift pumice was collected from a total of 40 beaches around the main island of New Caledonia, Southwest Pacific. This island is enclosed by a barrier reef lagoon whose 2008 designation as a UNESCO World Heritage Site brought attention to the ongoing environmental degradation caused by a century of open cast nickel mining. This type of mining is notorious for producing voluminous fine-grained waste sediment that clogs waterways and may compromise the biodiversity of the lagoon. This study examines the use of drift pumice as a visual marker of suspended sediment transported within and around the lagoon. The frequent, voluminous pumice eruptions in the region provide ample source material that is fairly durable and highly mobile in water. Geochemical analyses identified two recent eruptions in the central Tonga arc as the source of the pumice, which was transported to New Caledonia by the South Equatorial Current. Pumice abundance was shown to correspond directly with the incoming wave intensity. Coupling pumice distribution data with information about the beach morphology, it is possible to use land-based data collection methods to identify at-risk coastal areas exhibiting elevated fluvial input with reduced marine influence. / Methods -- Study area -- Regional setting -- Geomorphology -- Geochemistry -- Petrography -- Discussion. / Department of Geological Sciences

A significant proportion of the South African coastline is composed of both soft (mostly sand) and hard (mostly bedrock) substrata, i.e. “mixed”. This study described and classified macrobenthic assemblages of 20 Eastern Cape mixed substrate shores that differed in shore topography and the extent and position of intertidal rock and sand. A stratified random approach was used. Species richness, composition, abundance and environmental variables were determined. Commonly used beach indices were calculated. A total of 78 macrofaunal and 172 macroalgal species from rock substrate assemblages and 205 macrofauna species from sediment were recorded. Total species richness and richness per substratum exceeded that of sandy beaches devoid of rock and rocky shores with no sand. Rhodophyta were the most diverse and abundant algae, dominating all low-elevation rock surfaces as midlittoral and infralittoral turfs. Chlorophyta diversity was higher than at rocky shores, contributing more to cover-abundance at study sites and in microhabitats with an increased sand load. Sessile macrofauna species richness and abundance was lower than that of rocky shores. Polychaetes and crustaceans were the most diverse and abundant beach infauna. Species richness of both substrates declined from the low shore towards the high shore, but abundance trends varied substantially. The presence and extent of an intertidal biotope/subzone at either substrate depended on substrate availability.The supralittoral fringe in both substrate types was most often affected. Zonal overlap was evident on rock substrate: assemblages of raised midlittoral rock surfaces were enriched by species from lower surfaces sometimes leading to elimination of character taxa. Classification and ordination identified three potential mixed substrate shore biotic types: Biotic type A (Jania-Corallina- Polysiphonia turf) was characterised by robustly-textured algal turfs, a lowered predominance and diversity of polychaetes and an increase in crustacean abundance and diversity in sediment. Biotic type B (Polysiphonia-Tayloriella-Caulacanthus turf) had intermediately and biotic type C (Arthrocardia-Laurencia turf) the most sheltered eulittoral zones and beaches. DCCA identified the major environmental parameters affecting the macrobiota as: the level of wave energy, geological control of waves by hard substrate, sediment grain size and sediment inundation. A strong cross-shore wave attenuation results in sheltered sediments and midshore rock surfaces. Beach macrofauna were highly variable and diverse, which directly opposes previous perceptions about the sediment-bound biota of mixed substrate shores. The hierarchical cluster analysis produced a biotic classification of mixed substrate shores that was indicative of a biotic response to the total effects of leading environmental parameters. Macrobenthos of rock surfaces and sediment therefore showed potential to be used as an alternative or complementary to physical characteristics in classifying mixed substrate shores.

Tang Wai Lun. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2005. / Includes bibliographical references (leaves 199-220). / Abstracts in English and Chinese. / Abstract --- p.ii / 摘要 --- p.iv / Acknowledgements --- p.vi / Table of contents --- p.vii / List of Abbreviations --- p.xi / List of Tables --- p.xii / List of Figures --- p.xv / Chapter Chapter One --- Literature Review --- p.1 / Chapter 1.1 --- Marine pollution in Hong Kong --- p.1 / Chapter 1.2 --- Contamination of sediments --- p.3 / Chapter 1.2.1 --- Metals contamination in coastal sediments in Hong Kong --- p.4 / Chapter 1.2.2 --- Other contaminants in sediments --- p.7 / Chapter 1.3 --- Sediment toxicity assessment --- p.9 / Chapter 1.4 --- Fish as examples for the measurement of biological responses to contaminants --- p.9 / Chapter 1.5 --- Biomarkers for toxicity assessment --- p.11 / Chapter 1.5.1 --- Metallothionein (MT) --- p.11 / Chapter 1.5.2 --- Cytochrome P450 1A (CYP1A) --- p.13 / Chapter 1.5.3 --- Vitellogenin (Vtg) --- p.13 / Chapter 1.5.4 --- Enzyme biomarkers: Alanine transaminase (ALT); aspartate transaminase (AST) and creatine kinase (CK) --- p.14 / Chapter 1.5.5 --- DNA damage detected by the comet assay --- p.16 / Chapter 1.6 --- Multi biomarkers for sediment toxicity assessments --- p.16 / Chapter 1.7 --- Objectives --- p.16 / Chapter Chapter Two --- "Concentrations of Heavy Metals and Trace Organics in Coastal Sediments Collected from Victoria Harbour, Deep Bay, Tolo Harbour and Lai Chi Wo" --- p.18 / Chapter 2.1 --- Introduction --- p.18 / Chapter 2.2 --- Materials and Methods --- p.19 / Chapter 2.2.1 --- Sediment collection --- p.19 / Chapter 2.2.2 --- Treatment of sediment samples --- p.21 / Chapter 2.2.3 --- Acid wash of apparatus --- p.21 / Chapter 2.2.4 --- Acid digestion of sediment sample --- p.21 / Chapter 2.2.5 --- Sequential extraction of heavy metals in sediment samples --- p.22 / Chapter 2.2.6 --- Heavy metals measurement --- p.23 / Chapter 2.2.7 --- Trace organic measurement in sediments --- p.24 / Chapter 2.2.8 --- Statistical Analysis --- p.24 / Chapter 2.3 --- Results --- p.25 / Chapter 2.3.1 --- Concentrations of total Metals in sediments --- p.25 / Chapter 2.3.2 --- Speciation of metals in sediments --- p.27 / Chapter 2.3.3 --- Metal abundance in different fractions of sediment --- p.33 / Chapter 2.3.4 --- Concentrations of trace organic in sediments --- p.33 / Chapter 2.3.5 --- Results summary --- p.36 / Chapter 2.4 --- Discussion --- p.36 / Chapter 2.4.1 --- Comparison with international standards --- p.38 / Chapter 2.4.2 --- Comparison with international studies of coastal sediments --- p.39 / Chapter 2.4.3 --- Comparison of the present study with other studies concerning Hong Kong coastal sediments --- p.45 / Chapter Chapter Three --- "Heavy Metals Accumulation in Tissues of Tilapia Exposed to Coastal Sediments Collected from Victoria Harbour, Deep Bay, Tolo Harbour, and Lai Chi Wo" --- p.51 / Chapter 3.1 --- Introduction --- p.51 / Chapter 3.2 --- Materials and Methods --- p.52 / Chapter 3.2.1 --- Collection and treatment of coastal sediments --- p.52 / Chapter 3.2.2 --- Sediment exposure tests with Tilapia --- p.53 / Chapter 3.2.3 --- Dissection of fish samples --- p.54 / Chapter 3.2.4 --- Acid digestion of fish samples --- p.54 / Chapter 3.2.5 --- Statistical Analysis --- p.55 / Chapter 3.3 --- Results --- p.55 / Chapter 3.3.1 --- Metal accumulation --- p.55 / Chapter 3.3.2 --- "Dose, duration and source of sediments affecting metals uptake" --- p.95 / Chapter 3.3.3 --- Results summary --- p.99 / Chapter 3.4 --- Discussion --- p.99 / Chapter 3.4.1 --- Site comparison --- p.99 / Chapter 3.4.2 --- Comparison with other studies --- p.100 / Chapter 3.4.3 --- Safety limits --- p.112 / Chapter Chapter Four --- "Expression of Biomarker Genes (MT, CYP1 A, Vtg) in Tissues of Male Tilapia After Eexposure to Coastal Sediments Collected from Victoria Harbour, Deep Bay, Tolo Harbour and Lai Chi Wo" --- p.115 / Chapter 4.1 --- Introduction --- p.115 / Chapter 4.2 --- Materials and Methods --- p.116 / Chapter 4.2.1 --- Sample collection --- p.116 / Chapter 4.2.2 --- Preparation of apparatus --- p.117 / Chapter 4.2.3 --- mRNA expression analysis --- p.117 / Chapter 4.2.3.1 --- Isolation of RNA --- p.117 / Chapter 4.2.3.2 --- Reverse transcription --- p.118 / Chapter 4.2.3.3 --- Real time PCR --- p.118 / Chapter 4.2.4 --- Vitellogenin (Vtg) --- p.120 / Chapter 4.2.5 --- Statistics analysis --- p.121 / Chapter 4.3 --- Results --- p.121 / Chapter 4.3.1 --- MT mRNA expression in tissues of male Tilapia exposed to sediments --- p.121 / Chapter 4.3.2 --- CYP1A mRNA expression in tissues of male Tilapia exposed to sediments --- p.129 / Chapter 4.3.3 --- Vtg expression in tissues of male Tilapia exposed to sediments --- p.137 / Chapter 4.3.4 --- Dose and time dependent relationships --- p.137 / Chapter 4.3.5 --- Results summary --- p.137 / Chapter 4.4 --- Discussion --- p.142 / Chapter 4.4.1 --- Correlation of MT and CYP1A expression with metals uptake in gills and liver --- p.142 / Chapter 4.4.2 --- MT as a biomarker of metals exposure --- p.144 / Chapter 4.4.3 --- CYP1A as a biomarker of trace organics exposure --- p.145 / Chapter 4.4.4 --- Real-time PCR --- p.147 / Chapter 4.4.5 --- Vtg as a biomarker of xenoestrogen exposure --- p.147 / Chapter Chapter Five --- "Expression of Enzyme Biomarkers (ALT, AST and CK) in Tissues of Male Tilapia After Exposure to Coastal Sediments Collected From Victoria Harbour, Deep Bay, Tolo Harbour and Lai Chi Wo" --- p.149 / Chapter 5.1 --- Introduction --- p.149 / Chapter 5.2 --- Materials and Methods --- p.150 / Chapter 5.2.1 --- Samples collection --- p.150 / Chapter 5.2.2 --- Alanine transaminase (ALT) and Aspartate transaminase (AST) --- p.151 / Chapter 5.2.3 --- Creatine kinase (CK) --- p.152 / Chapter 5.2.4 --- Statistical analysis --- p.153 / Chapter 5.3 --- Results --- p.153 / Chapter 5.3.1 --- ALT --- p.153 / Chapter 5.3.2 --- AST --- p.157 / Chapter 5.3.3 --- CK in gills --- p.157 / Chapter 5.3.4 --- CK in muscle --- p.164 / Chapter 5.3.5 --- "Dose, duration and source of sediments affecting metals uptake" --- p.164 / Chapter 5.3.6 --- Results summary --- p.169 / Chapter 5.4 --- Discussion --- p.169 / Chapter Chapter Six --- "DNA Damage in Liver of Male Tilapia After Exposure to Coastal Sediments Collected from Victoria Harbour, Deep Bay, Tolo Harbour and Lai Chi Wo" --- p.174 / Chapter 6.1 --- Introduction --- p.174 / Chapter 6.2 --- Materials and Methods --- p.176 / Chapter 6.2.1 --- Samples collection --- p.176 / Chapter 6.2.2 --- Tissue Preparation --- p.176 / Chapter 6.2.3 --- Single Cell Gel Electrophoresis (Comet) Assay --- p.176 / Chapter 6.2.4 --- Image analysis --- p.177 / Chapter 6.2.5 --- Statistical analysis --- p.178 / Chapter 6.3 --- Results --- p.180 / Chapter 6.4 --- Discussion --- p.187 / Chapter Chapter Seven --- General Discussion and Conclusion --- p.190 / Chapter 7.1 --- General discussion --- p.190 / Chapter 7.2 --- Conclusion --- p.198 / References --- p.199 / Appendix --- p.221

Marine nitrogen (N) is an essential nutrient for all oceanic organisms. The cycling of N between biologically available and unavailable forms occurs through numerous reactions. Because of the vast number of reactions and chemical species involved, the N cycle is still not well understood. This dissertation focuses on understanding some of the reactions involved in the cycling of marine N, as well as improving techniques used to measure dissolved N2 gas. The largest loss term for global marine N is a reaction called denitrification. In this work, denitrification was measured in the sandy sediments of the Georgia continental shelf, an area where this reaction was thought to be unlikely because of the physical properties of the sediments. Nitrogen fixation, which is a reaction that produces biologically available N, was detected in Georgia estuarine sediments. N fixation was measured concurrently with denitrification in these sediments, resulting in a much smaller net loss of marine N than previously thought. Lastly, membrane inlet mass spectrometry (MIMS) is a technique that measures dissolved N2, the end product of denitrification and a reactant in N fixation reactions. This study suggests that N2 measurements by MIMS are influenced by O2 concentrations due to pressure differences inside of the ion source of the mass spectrometer. These findings seek to improve denitrification measurements using MIMS on samples with varying O2 concentrations. In conclusion, this dissertation suggests that the marine N cycle is more dynamic than has been suggested, due to the recognition of input and loss reactions in a wider range of marine and estuarine environments. However, improvements in the understanding of MIMS will help with direct measurements with reactions involved in the global marine N cycle.

No Cearà a zona costeira representa apenas 14,38% do territÃrio estadual, mas possui 48,9% da populaÃÃo do estado (IBGE, 2002. Na RegiÃo Metropolitana de Fortaleza (RMF) a densidade demogrÃfica da Zona Costeira Cearense (ZCC) aumenta para 598,00 hab/km2, atingindo valores ainda maiores quando focada a cidade de Fortaleza (6.814 hab/km2). Na dÃcada de 70, Fortaleza teve um salto de crescimento urbano, desordenado, na sua Ãrea costeira, com uma sÃria de construÃÃes que afetaram de maneira direta a sua linha de costa, tais como o antigo e atual porto de Fortaleza. Assim, este estudo teve por objetivo avaliar a influÃncia das atividades antrÃpicas sobre a emissÃo de metais e sobre a distribuiÃÃo e partiÃÃo geoquÃmica destes metais contidos nos sedimentos da regiÃo costeira da RMF. Analisados os teores de Hg, Cu, Cd, Pb, Zn, Al e Fe, nos sedimentos costeiros coletados em duas campanhas, nos perÃodos de chuva e seca, nÃo foi encontrada diferenÃa estatÃstica entre resultados obtidos relativos Ãs diferentes campanhas, exceto para o Fe. Os teores mÃdios obtidos foram: 0,72 a 17,54 ng.g-1 de Hg, 0,32 a 4,64 μg.g-1 de Cu, 0,13 a 0,77 μg.g-1 de Cd, 3,29 a 13,00 μg.g-1 de Pb, 1,81 a 18,64 μg.g-1 de Zn, 0,78 a 9,12 mg.g-1 de Al, 0,76 a 9,27 mg.g-1 (PerÃodo chuvoso) e 1,28 a 13,92 mg.g-1 (PerÃodo de seca) de Fe. Todos os metais apresentaram correlaÃÃes significativas com os principais carreadores geoquÃmicos, isto à com a matÃria orgÃnica, o alumÃnio e o ferro, menos com os carbonatos, mostrando que este substrato nÃo à um retentor geoquÃmico eficaz de metais. Apesar do oceano ser um bom diluidor de contaminantes foi verificado Ãreas de concentraÃÃes de metais prÃximas à linha de costa, à regiÃo do porto e à saÃda do EmissÃrio Submarino de Fortaleza (ESF) se dispersando no sentido E-W da deriva litorÃnea. O ESF mostrou-se ser fonte pontual de mercÃrio, cobre, zinco, cÃdmio e chumbo, entretanto o enriquecimento do sedimento por Hg, Cu e Zn ainda à de baixo grau. TambÃm foi observado que o runoff urbano à importante emissor de Cd e Pb, tendo em vista as elevadas concentraÃÃes encontradas prÃximas à linha de costa. A distribuiÃÃo dos metais mostrou que hà dois importantes fatores determinantes do comportamento destes metais em sedimentos costeiros da RMF. O primeiro fator està relacionado aos carreadores geoquÃmicos que predominantemente influenciam o comportamento do cobre, do chumbo e do zinco. O segundo fator està relacionado à proximidade e/ou intensidade das Ãreas fontes e dominou o comportamento do Hg e do Cd. / The coastal zone of Cearà State corresponds to only 14.38% of the Stateâs territory but harbors about 48.9% of its total population. The Metropolitan Region of Fortaleza (RMF), the Stateâs Capital population density at the coastal zone reaches 598 inhab/km2, and 6.814 inhab/km2 when only the city of Fortaleza itself is considered. During the 1970âs, Fortaleza witnessed an accelerated and unplanned urban growth along its coastal zone including engineering works, which affected the coastline itself, including the Fortaleza Harbor and may have increased pollutants emissions to the coastal region. Therefore, this study aims to evaluate the influence of these antropogenic developments on the emissions of trace metals and their distribution and geochemical partitioning in bottom sediments collected along the RMF coastal region. In two field campaigns, in the rain and dry season, the concentrations of Hg, Cu, Cd, Pb, Zn, Fe and Al, were measured in bottom sediments of the coastal zone. There was no significant difference between the two campaigns for all trace metals, except for Fe. Measured concentrations varied between 0.72 to 17.54 ng.g-1 for Hg; 0.32 to 4.64 μg.g-1 for Cu; 0.13 to 0.77 μg.g-1 for Cd; 3.29 to 13.00 μg.g-1 for Pb; 1.81 to 18.64 μg.g-1 for Zn; 0.78 to 9.12 mg.g-1 for Al, 0.76 to 9.27 mg.g-1 (rain season) and 1.28 to 13.92 mg.g-1 (dry season) for Fe. All trace metals concentrations presented significant positive correlation with the major geochemical carries analyzed, i.e. organic matter content, Aluminum and Iron, except for carbonates, carbonates are not efficient carriers of metals in these metals. Although the oceanic water mass acts as a large diluter of contaminants, areas of higher trace metal concentrations were observed close to the shoreline, at the area of influence of the Fortaleza Harbor and near the outlet of a submarine wastewater outfall. Concentrations decrease in an E-W direction following the littoral drift. The submarine wastewater outfall of Fortaleza showed an important point source of Hg, Cu, Zn, Cd and Pb. Although absolute concentrations of these trace metals were, in general, low. The higher concentrations along the shoreline suggest that urban runoff is also a significant source of trace metals, in particular of Cd and Pb. The spatial distribution of trace metals concentrations showed two important factors determining the behavior of trace metals in the bottom sediments of the RMF. The first factor is related to the concentrations of the geochemical carriers, which influence the behavior of Cu, Pb and Zn. The second factor is the proximity and/or the intensity of area sources and dominated the behavior of Hg and Cd.

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.

Sedimentos de regiões costeiras são caracterizados por altas concentrações de matéria de orgânica. As bactérias desempenham um fator chave na decomposição da matéria orgânica e na reciclagem de nutrientes inorgânicos essenciais. Além de representar um dos mais importantes recursos alimentares para a meio- e macrofauna. O presente estudo teve por objetivo avaliar a abundância e biomassa da comunidade bacteriana bêntica de duas enseadas na região costeira de Ubatuba (SP), relacionando-as ao aporte de matéria orgânica de diferentes fontes (marinha, terrestre e antrópica) e à estrutura da comunidade bêntica. Foram realizadas seis coletas bimensais em quatro estações por enseada ao longo de um transecto costa-oceano. O sedimento de cada testemunho foi fatiado a bordo em três camadas (0-2, 2-5 e 5-10 cm). A análise bacteriana foi conduzida através de contagem direta em microscópio de epifluorescência e a atividade através da freqüência de células em divisão. A análise dos parâmetros sedimentares como granulometria, qualidade e quantidade de matéria orgânica, bem como dados de macro e meiofauna foram obtidos através do Projeto DIAGEN, do qual o presente estudo faz parte. Os resultados de densidade e biomassa bacteriana mostraram valores sempre maiores na enseada de Ubatuba em relação à Fortaleza, acompanhado por teores mais elevados de matéria orgânica total, clorofila-a, feopigmentos e biomassa microbiana. O padrão de deposição das enseadas provavelmente teve papel decisivo nos altos valores de biomassa e densidade bacteriana nas regiões centrais e rasas das enseadas. Densidades e biomassas bacterianas mais elevadas foram encontradas no inverno (junho de 2005), não sendo observadas relações direta com os valores de matéria orgânica total ou clorofila-a. O estudo mostrou uma alta atividade bacteriana na camada superficial do sedimento, em especial no outono, com valores sempre maiores na enseada de Fortaleza, contrastando com os valores de densidade e biomassa. / Coastal sediments are characterized by high organic matter contents. Bacteria play a key role in organic matter decomposition and are essential in the nutrient recycling process. Moreover, represent an important food source for meio- and macrofaunal organisms. The present study aimed to evaluate the abundance and biomass of the benthic bacterial community in two bays of the coastal region of Ubatuba (SP). Bacterial abundance and biomass were compared with the distribution and abundance of different organic matter sources (marine, terrestrial and anthropogenic) and with the structure of the benthic community. We collected samples every two months for a period of one year in four stations on each bay along a coast-ocean transect. Tube cores were used to collect sediment samples, which were sliced on board in three layers (0-2, 2-5 and 5-10 cm). Bacterial abundance and biomass were counted and measured under epifluorescence microscopy and bacterial activity was estimated by the frequency of dividing cells. Information on sediment grain size distribution, quality and quantity of organic matter, as well as macro- and meiofauna were available from Project DIAGEN, from which this study is part. Bacterial density and biomass were always higher in Ubatuba bay, which appeared to be related to larger amounts of total organic matter, chlorophyll-a, pheopigments and microbial biomass. The differential deposition pattern observed in both bays was probably important determining the higher values of bacterial biomass and density found in the central and shallow portions of the bays. Despite higher bacterial density and biomass were found during the winter (June 2004) in most stations, this seemed not to be related to total organic matter or chlorophyll-a. Bacterial activity was high in surficial sediments, especially during autumn, with consistently larger values in Fortaleza bay.