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In this study, we examined the epiplastic microalgal community that developed on low-density polyethylene (LD-PE) plastic debris found in two distinct regions of the Monastir Bay (Tunisia): the coast exposed to anthropogenic discharges and the open sea in front of the Kuriat Islands. The analysis of trace elements accumulated in the plastisphere was also carried out. The collected plastispheres were predominantly composed of cyanobacteria. Chlorophytes and diatoms were also found. Euglenophyceae was also recorded but with comparatively low relative abundance (RA), whereas dinoflagellates were almost absent. The diatom showed a high diversity of species (25 species). Potentially harmful microalgae (PHM) were more abundant in the plastisphere than in seawater at all stations. For all coastal area stations, most of the PHM colonizing the plastisphere are potentially harmful cyanobacteria. For S1 (offshore station), the PHM community profile was characterized by the dominance of potentially harmful diatoms. The main potentially harmful cyanobacterium identified on the plastisphere was Phormidium sp. Pseudo-nitzschia spp. was the only potentially harmful diatom observed on the plastisphere. Accumulation of trace elements in plastisphere was higher than that in sediments. Trace elements in plastisphere are ranked with a very high contamination factor at all sites, according to the sequence Pb > Cu > Cd > Ni > Zn. The accumulation of trace elements in the plastisphere is highest near areas with harbor and industrial activities and the urban rejects zone.

portuguesO Complexo Pedra Branca (CPB) esta localizado na zona oeste da cidade do Rio de Janeiro (SE Brasil) e esta inserido tectonicamente no Dominio Costeiro, pertencente ao Terreno Oriental da Faixa Ribeira Central. Os litotipos que formam o CPB foram gerados em eventos relacionados a Orogenese Brasiliana (~600 Ma), abrigando assim rochas pre- a pos-colisionais. Estudos anteriores de corpos graniticos pos-tectonicos na Faixa Ribeira revelaram que o magmatismo ocorreu em dois pulsos distintos, com intervalo de aproximadamente 30 Ma entre eles. O presente estudo analisou 9 amostras do CPB, atraves dos metodos geocronologicos U-Pb e Lu-Hf via LA-ICP-MC-MS, referentes as litologias granito Pedra Branca e granito Favela, possiveis representantes do pulso mais antigo e mais jovem, respectivamente, buscando melhorar a compreensao do magmatismo pos-tectonico na regiao. As medias das idades encontradas para o granito Pedra Branca (509 ± 5 Ma) e granito Favela (489 ± 6 Ma) corroboraram com os valores descritos na literatura e indicaram que o magmatismo ocorrido no CPB teve origem na forma de pulsos progressivos, porem num intervalo de tempo menor (~20 Ma) do que foi anteriormente determinado. O indicador petrogenetico eHf indicou participacao de fontes crustais e mantelicas, dando carater bimodal ao magmatismo registrado no CPB EnglishThe Pedra Branca Complex is located at the western region of the Rio de Janeiro city (SE Brazil). Tectonically it is inserted in the Coastal Domain, which is part of the central segment of the Ribeira Belt. The lithologies that formed this rocky complex were generated in events related to the Brasiliano Orogeny (~ 600 Ma), thus contains pre- to- post-collisional rocks. Previous studies on post-tectonic granite bodies belonging to Ribeira belt revealed that the magmatism occurred in two distinct pulses, with an interval of approximately ~ 30 Ma between them. The present study analyzed 9 CPB samples, using the U-Pb and Lu-Hf through LA-ICP-MC-MS geochronological methods, with focus on the Pedra Branca granite and Favela granite, which may represent the older and the younger pulses respectively, in order to improve the understanding of the post-tectonic magmatism in the area. The average ages found for the Pedra Branca (509 ± 5 Ma) and Favela (489 ± 6 Ma) granites confirm the previously described ages in the literature. However, they indicate that the magmatism in CPB occurred in the form of progressive pulses, with an interval between both events of ~ 20 Ma, that is, less than what was previously estimated (of ~ 30 Ma). In addition, the petrogenetic indicator eHf indicated the participation of crustal and mantle sources, which gives a bimodal character to the magmatism registered in the CPB

A Baía de Guanabara, um dos mais importantes sistemas costeiros do sudeste brasileiro, com os seus primeiros rasgos estruturais durante o pré-cambriano e instalação definitiva durante o Cenozoico, tem vindo a ser modelada por processos relacionados com alterações climáticas e mais recentemente pela forte atividade antrópica, na região. Este trabalho pretende efetuar uma síntese de registros sedimentares históricos relacionados com a ação antrópica no entrono da Baía de Guanabara e definir o início do Antropoceno neste sistema costeiro.Em adição, os resultados desta investigação permitem a divisão do Antropoceno em quatro periodos de sedimentação na Bia da Guanabara.A documentação e os dados analisados permitem considerar que a camada sedimentar que marca o início do Antropoceno, na Baía de Guanabara foi depositada em 1502 (Ano Domine), no decurso da “Pequena Idade do Gelo”, ano a partir do qual teve início o processo de ocupação colonialista dos Portugueses. Esforços de ocupação e defesa local após o descobrimento, em 1502, culminou com a criação da cidade do Rio de Janeiro, em 1565.A partir de então observam-se no registro sedimentar a redução granulométrica dos sedimento, em plena Pequena Idade do Gelo, aumento progressivo dos teores de matéria orgânica mudanças polínicas resultantes do desmatamento para extração do pau-brasil, para a cultura da cana-de-açúcar, que se estendeu dos séculos XVI ao XIX, e do café nos séculos XVIII e XIX. De meados do séc. XVIII ao início do séc. XX inicia o ciclo da mineração, seguida do começo do ciclo da industrialização e principia de forma incipiente a poluição danosa na Baía de Guanabara. O desenvolvimento industrial, a partir da invenção da máquina a vapor, associado à necessidade de matéria-prima, conseguida a baixo custo nos países colonizados à época, marcou a segunda fase do Antropoceno na Baía de Guanabara, a partir de meados do século XVIII e que terá durado até ao início do século XX. Esta fase é identificada em registros sedimentares onde ocorre aumento expressivo de metais.Início do séc. XX ao início dos anos 50 a alteração de mais de 10 Km da orla ocidental da baía próxima a desembocadura causa a alteração do padrão hidrodinâmico dando lugar a um aumento acentuado da acumulação de sedimentos finos em vastas áreas da Baía de GuanabaraA quarta fase do Antropoceno, após meados do século XX, teve lugar num cenário de grande crescimento demográfico e industrial. A Baía de Guanabara passou a recolher o excedente sedimentar provocado pelas intervenções antrópicas acrescido do aumento dos resíduos domésticos (lixo em geral e esgoto) e industriais (óleo, metais pesados, substâncias tóxicas e carga orgânica) oriundos da expansão das atividades no seu entorno, acarretando a aceleração da perda de sua área de superfície e de profundidade.

This work studies the Buracica Stage (Barremian, Early Cretaceous) in the Reconcavo Basin, Bahia State (N.E. Brazil), comprising the Sao Sebastiao and Pojuca formations, from the analysis of 143 well logs and outcrop records. The Reconcavo Basin is a rift basin associated with the beginning of the South Atlantic Ocean. The basin started with very slow subsidence rates, leading to the formation of shallow lakes and the deposition of shales and sandstones, which compose the Brotas Group; later, subsidence accelerated and gave rise to the formation of a deep lake. Then the deep lake basin was filled throughout six depositional episodes making up the so-called Reconcavo tectonic sequence. Previous studies divided the last depositional event of Reconcavo Basin into seven fourth-order sequences concerning the Marker Bed “1” to the Marker Bed “F” stratigraphic interval. Sequence boundaries were marked by sharp flooding surfaces related to the transgression of lacustrine system due to rapid tectonic subsidence and generation of accommodation. In turn, the sequences are divided into three systems tracts: the lake lowstand systems tract, the transgressive systems tract and the lake highstand systems tract. The maximum flood surface of the sequences generally coincides with the stratigraphic marker “B” to “F”. Depositional systems like braided-fluvial plus eolian dunes, meandering-fluvial, deltaic, or moving-lake and near-shore deposits were identified in this work. Isopach, isolith and sand percentage maps indicate depocentre and source area distribution like the previous Aratu Stage. The primary sources of the sediments are located in the west and north areas; only from the third sequence, an eastern source could be described conspicuously. The fourth-order cyclicity is controlled by lake level changes, related to climatic factors (Milankovitch cycles). The results from the studies of cyclicity confirm the proposed stratigraphic model. They indicate 43,000 years for each fourth-order sequence and 150,000 years for the third-order sequences, which provide an accumulation rate of 1200 mm per 1000 years for the studied interval.

This work analyzes the results of the SP2 core (50.30 m length) collected in the coastal plain of Sepetiba Bay (SB; SE Brazil), 2 km away from the Guandu River mouth (latitude 22° 55′S, longitude 43° 46′W). It aims to study the influence of the Holocene relative sea level (RSL) on the coastal plain of SB. After description, the SP2 core was sampled at every 5 cm for grain size, geochemical, mineralogical and foraminiferal analyses. Four radiocarbon dates obtained in the first 18 m were modulated with Bayesian statistics. The SP2 core is composed of basement rocks, gneisses (50.30–43.80 m); river sediments (43.80–21.00 m) up to about ≈ 5.0 kyr BP; a sediment package marked by sudden textural and compositional changes, accumulated between ≈ 5.0 and 4.7 kyr BP; muddy sediments deposited between 4.7 and 0.8 kyr BP (18.80–3.35 m) with intercalations of sandy levels; an upper part of disturbed embankment sediments used for the implantation of Santa Cruz Thermoelectric Power Plant. The fluvial sands accumulated before ≈ 5.0 kyr BP were deposited before the maximum Mid-Holocene relative sea level. They were probably eroded and transported by the drainage network of the N region of SB, namely by the Guandu River. Between ≈ 4.5 and 3.5 kyr BP, the foraminiferal abundance and assemblage composition indicate that the study site was a shallow marine environment, due to the Mid-Holocene relative sea-level highstands (MHSLH). Between ≈ 3.5 and 3.0 kyr BP, the sediment accumulation rate (SAR) was the lowest of the last ≈ 5 kyr BP and the study site was exposed to subaerial weathering processes, in a scenario of the relative sea-level drop. A new phase of marine influence was recorded between ≈ 3.0 and 1.9 kyr BP, associated with the highest SAR of this record, up to ≈ 27.4 m/kyr BP. Between ≈ 1.9 and 1.8 kyr BP, the study site was under subaerial weathering processes. Since then the SAR reduced significantly to a mean value of ≈ 4.5 m/kyr and, between ≈ 1.8 and 0.8 kyr BP, the study site was again under the marine influence. Foraminifera were not found, after ≈ 0.8 kyr BP, in the SP2 core. However, the occurrence of a shallow marine environment was identified in another core, between ≈ 1.4 and 0.35 kyr BP, in the Guaratiba Mangrove, NE of SB. The results of the SP2 core suggest that MHSLH left a striking record in the study area, although some of the identified environmental changes are probably related to adjustments of the lower course of Guandu River and tidal channels and variations in the configuration of sandy littoral strands. The growth of a barrier–island system, the Marambaia barrier island, since the last ≈ 8–7.5 kyr BP may also have induced changes in the study area.

Living (stained) benthic foraminifera from the continental shelf of Santos Basin, southeastern Brazilian continental margin, were investigated to understand their distribution patterns and their relationship with chlorophyll-a and particulate organic matter contents. Sediments were collected from 44 to 203 m of water depth. This study analysis benthic foraminifera and abiotic data, including grain size, total organic matter, distributions of ocean chlorophyll-a and particulate organic matter. Foraminiferal diversity and richness were positively correlated to the chlorophyll-a and particulate organic carbon contents. Stations located on the southern portion of the study area and sampled during austral winter are probably under the seasonal influence of the Brazilian Coastal Current intrusion, and Rio de la Plata and Lagoa dos Patos plumes. Ammonia rolshauseni, Textularia? sp. and Gyroidina umbonata are present within the foraminifera assemblages at these stations. On the other hand, stations in the north, are characterized by the presence of Uvigerina peregrina, Quinqueloculina atlantica, Hanzawaia concentrica and Bulimina marginata, and they are influence of Cabo Frio’s southward-moving plume.

The Araçuaí and Ribeira orogens have been studied for decades, and recently, these two orogens were described as the Araçuaí–Ribeira Orogen System. Despite much work investigating this orogenic system, some issues, such as the connection between the two orogens, are still not fully understood. This work aimed to present unpublished Lu-Hf data for the Santa Angélica Intrusive Complex (SAIC) and for the host rocks that are part of the Rio Negro magmatic arc, as well as to present U-Pb ages for these rocks, thus contributing to the understanding of the geological processes that acted in the transition zone between the Araçuaí and Ribeira orogens. Two samples were collected corresponding to the magmatic arc and six samples from the Santa Angélica Intrusive Complex. The zircon grains were separated from the samples and subjected to geochronological (U-Pb) and isotopic (Lu-Hf) analysis by laser ablation-induced coupled plasma mass spectrometry (LA-ICP-MS). The geochronological data for the host rocks indicate a crystallization age of ca. 595 Ma. In contrast, the Hf isotopic data point to at least two magmatic sources, one crust, and one mantle. The geochronological data obtained for the SAIC rocks show three age peaks. The first peak (537 ± 5 Ma) coincides with the process of crustal anatexis and possibly marks the beginning of the generation of magmas associated with post-collisional magmatism. The second peak (510 ± 5 Ma) registers the apex of crystallization of the SAIC, and the third peak of ages (488 ± 7 Ma) marks the upper limit of the magmatism in the SAIC. The SAIC isotopic data point to at least two crustal components and a mantle component (juvenile).

The main objective of this work is to analyze the consequences of eutrophication in benthic meiofaunal organisms (foraminifera) in an internal area of Sepetiba Bay (State of Rio de Janeiro, SE, Brazil). This study is interesting because, at the studied site, the sediments corresponding to the period of greatest accumulation of organic matter were not contaminated by metals, although Sepetiba Bay has areas known to be polluted by this type of contaminants. Thus, in this study, it was possible to consider only the impact caused by eutrophication. In the SP6 core, collected in the Sepetiba Bay internal area and studied in this work, textural, geochemical (concentration of chemical elements; 210 Pb and 137 Cs; radiocarbon data) and foraminifera were analyzed in a muddy section, with a few intercalations of sandy layers. The sediments of the analyzed section were deposited in the last ≈2,350 BP years. The concentrations of Al, Cd, Co, Fe, Mn, Ni, Pb, Sn, Ti, V and Zn are higher at the base of the core and decrease towards the top. The contents of TOC, P and Zr have inverse paterns. The ratios of these elements to their background value have similar patterns. However, previous studies have recognized that during the twentieth century Cd, Zn, Cr and Pb concentrations increased in several areas of Sepetiba Bay, mainly due to industrial activity. The area where this core was collected may have been dredged. Radiocarbon ages suggest a loss of ≈2000 years of sedimentary registration, marked by an unconformity at a depth of 126 cm, probably caused by dredging. A new sedimentary sequence unpolluted by metals but highly enriched in organic matter was deposited on the surface of that discontinuity. Foraminifera were quite abundants in the lower section (240-126 cm; between ≈2,400-2,090 years BP, execept in the sandy layers), corresponding to sediment deposition before dredging. After dredging, the accumulation of very fine-grained sediments rich in organic matter generated eutrophication phenomena, which caused a drastic reduction in the abundance and diversity of these organisms. This work testifies the effect of eutrophication on meiofaunal organisms. Although some coastal foraminifer species tolerate harmful effects caused by eutrophication, it is recognized that the impact has been so negative that even these species occur with reduced abundance in the study area. IMPACTO DA EUTROFICACAO EM FORAMINIFEROS BENTONICOS NA BAIA DE SEPETIBA (ESTADO DO RIO DE JANEIRO, SE BRASIL) Resumo O principal objetivo deste trabalho e analisar as consequencias da eutrofizacao em organismos meiofaunais bentonicos (foraminiferos) em uma area interna da Baia de Sepetiba (Estado do Rio de Janeiro, SE, Brasil). Este estudo e interessante porque, no local estudado, os sedimentos correspondentes ao periodo de maior acumulacao de materia orgânica, nao estavam contaminados por metais, apesar da Baia de Sepetiba ter areas reconhecidamente poluidas por este tipo de contaminantes. Assim neste estudo foi possivel considerar apenas o impacto causado pela eutrofizacao. No testemunho SP6, coletado na area interna da Baia de Sepetiba e estudado neste trabalho, foram analisados dados texturais, geoquimicos (concentracao de elementos quimicos; 210 Pb e 137 Cs; dados de radiocarbono) e foraminiferos numa seccao lamosa, com intercalacoes de camadas arenosas. Os sedimentos da secao analisada foram depositados nos ultimos 2.350 anos BP. As concentracoes de Al, Cd, Co, Fe, Mn, Ni, Pb, Sn, Ti, V e Zn sao mais elevadas na base do testemunho e diminuem em direcao ao topo. O conteudo de TOC, P e Zr possui padroes inversos. As razoes destes elementos com o respectivo valor de fundo possuem padroes semelhantes. Porem, estudos anteriores reconheceram em varias areas da Baia de Sepetiba um aumento das concentracoes de Cd, Zn, Cr e Pb durante o seculo XX, principalmente devido a atividade industrial. A area onde foi coletado este testemunho podera ter sido dragada. As idades de radiocarbono sugerem uma perda de aproximadamente 2000 anos de registro sedimentar, marcada por uma inconformidade a 126 cm de profundidade, causada provavelmente por dragagem. Uma nova sequencia sedimentar nao poluida por metais, mas bastante enriquecida em materia orgânica foi depositada sobre a superficie da descontinuidade. Os foraminiferos eram relativamente abundantes na secao inferior (240-126 cm; entre ≈2.400-2.090 anos BP), correspondente a deposicao de sedimentos antes da dragagem. Apos a dragagem, a acumulacao de sedimentos muito finos e ricos em materia orgânica, gerou fenomenos de eutrofizacao, que terao causado uma reducao drastica da abundância e diversidade destes organismos. Este trabalho testemunha o efeito da eutrofizacao em organismos meiofaunais. Apesar de algumas especies de foraminiferos costeiros tolerarem efeitos nefastos causados pela eutrofizacao, reconhece-se que o impacto foi tao negativo que mesmo estas especies ocorrem com abundância reduzida na area estudada. Palavras-chave: Area Costeira. Registro Paleoambiental. Impacto Antropico. Meiofauna, Abordagem Multiproxy.

The present research was developed aiming to study macroscopically the effects of karstification that, over the time, affected significantly the carbonated massif in Khózuè, Cheringoma Plateau (Mozambique). The research was carried out from a field study (collecting samples and photos) for a period of one week, in May of 2017, in Khózuè. During the field work, evidences found in nature were recorded as well as, the mode of occurrence of several structures (caves, dolines and speleothems). The karstification in the study area that occurs in the Cheringoma Formation (from Middle Eocene) was greatly conditioned by fractures which influenced the process and formation of caves and dolines. These structures tended to follow morphological patterns depending on guide fractures orientation allied to their genesis and creating, in certain cases, dolines with a cross morphology. In addition to caves and dolines, karstic activity in the Cheringoma Formation massif also created other structures, especially speleothems, which are not widespread, and also preservation/fossilization of plant remains by mineralization. Chemical weathering chemical weathering, but especially internal geodynamic phenomena transformed the Khózuè massif one karst region with peculiar characteristics. ResumoEste trabalho foi desenvolvido com o objetivo de estudar macroscopicamente os efeitos da carstificação que, com o tempo, afetaram significativamente o maciço carbonatado de Khózuè, no platô de Cheringoma (Moçambique). A pesquisa foi realizada a partir de um estudo de campo (coleta de amostras e fotografias), em 2017, em Khózuè. Durante as atividades de campo, foram analisadas as estruturas encontradas na área de estudo, tal como a ocorrência de falhas, cavernas, dolinas e espeleotemas. A carstificação na área de estudo, associada á Formação Cheringoma (do Eoceno Médio), foi muito influenciada por falhas. Estas favoreceram a formação de cavernas e dolinas. Essas estruturas tenderam a assumir padrões morfológicos condicionados pela orientação de falhas. Em certos casos, as falhas deram origem por exemplo a dolinas em forma de cruz. Além de cavernas e dolinas, a atividade cárstica no maciço da Formação Cheringoma deu lugar também a outras estruturas, como por exemplo, espeleotemas encontrados em apenas alguns locais e a processos de preservação/fossilização por mineralização de restos vegetais. A meteorização química, mas sobretudo fenómenos de geodinâmica interna transformaram o maciço calcário de Khózuè uma região cárstica com características peculiares. Palavras-chave: Karstificação. Cavernas. Dolinas. Espeleotemas. Fossilização. Fraturas.

The Petroleum Terminal Pipeline “Dutos e Terminais do Centro Sul (DTCS)” is one of the largest petroleum terminals in Brazil. To assess wastewater treatment efficiency of the DTCS and to evaluate the contamination by potentially toxic elements (PTE) of sediments, ten sampling points were studied near the riser output of the submarine outfall in the summer of 2005, 2006 and 2007, and ten sampling points were studied along the São Sebastião Channel (CSS). All data were above the standards required by the Brazilian salt water/brackish Water Directives (CONAMA Resolution 454/2012). However, the sediments near the submarine outfall were enriched by As and Cu, with concentrations exceeding the threshold effect level (TEL). In 2005 and 2006, the concentrations of Ba, Sr, Ni and Pb exceeded the values established by TEL in some places. Concentrations of As were 69 times higher than that measured in the background station. In 2007, all the analyzed metals almost doubled the concentrations of that found in 2005. High concentrations of PTE in the sediments, namely Ba and As, are a source of contamination that should be considered for the water quality management planning of the DTCS system. Avaliação da Contaminação por Elementos Químicos Potencialmente Tóxicos (PTE) dos Sedimentos da Região do Terminal Petrolífero “Dutos e Terminais do Centro Sul (DTCS)”, SP, Brasil ResumoO Terminal Petrolífero “Dutos e Terminais do Centro Sul (DTCS)”, SP, Brasil é um dos maiores terminais de petróleo do Brasil. Para avaliar a eficiência do tratamento de águas residuais do DTCS e estimar a contaminação por elementos potencialmente tóxicos (PTE) dos sedimentos, foram estudados dez pontos de amostragem perto da saída do ducto submarino no verão de 2005, 2006 e 2007 e dez pontos de amostragem ao longo do Canal de São Sebastião (CSS). Todos os dados estavam acima dos padrões exigidos pelas Diretrizes Brasileiras para Águas Salgadas/Salobras (Resolução CONAMA 454/2012). No entanto, os sedimentos perto do exutor submarino estavam enriquecidos por As e Cu, tendo as concentrações excedido o nível limiar de efeito (TEL; the threshold effect level). Em 2005 e 2006, as concentrações de Ba, Sr, Ni e Pb ultrapassaram os valores estabelecidos para o TEL. As concentrações de As foram 69 vezes superiores às medidas na estação de fundo. Em 2007, todos os PTE tinham quase duplicado as concentrações de 2005. As altas concentrações de PTE nos sedimentos, nomeadamente Ba e As, são uma fonte de contaminação que deve ser considerada no planejamento da gestão da qualidade da água do sistema DTCS. Palavras-chaves: Elementos Químicos Potencialmente Tóxicos. Sedimentos. Emissários Submarinos. Efluentes Petroquímicos.

The coastal areas, the most populated regions in the world, are those which have undergone the greatest human influence. In Brazilian southeastern coast, the region around Guanabara Bay (GB) is one of the most densely populated, with large cities, such as Rio de Janeiro and Niteroi, and is highly industrialized. Due to anthropic activities tones of effluents, waste and sewage is daily released in GB. Despite, several works have been performed aiming to study the current and past human influence in GB, the sources of pollutants that have impacted this bay since the late nineteenth century. This work is a new contribution aiming to identify the main sources of pollution in the northern/northeast region of GB using stable isotopes of lead (Pb) and metal concentrations during the last decades. It analyses results obtained along the core T3 collected in the northeast region of Guanabara Bay, near the Guapimirim Environmental Protected Area (known as Apa de Guapimirim), a mangrove fringe. Twenty-two sediment samples collected along this core were submitted to grain size, total organic carbon content (TOC), elemental concentrations (Ag, Ca, Cu, P, Pb, S and Zn) and stable isotopes of lead (Pb) analyses. The sediment accumulation rate was estimated by 210 Pb. Results of core T3 were compared with similar data acquired in core T8, collected in Guanabara Bay, at north of Paqueta island. The comparison of the geochemical results allowed to verify that both cores recorded the same reality. Previous works have shown that the northern/northeast region of Guanabara Bay is low polluted by metals, however, since the ≈1950 a marked increase in eutrophication and metal contamination and another noticeable pulse after ≈1970, were recorded in both cores studied in this work. The 206 Pb/ 207 Pb values suggest that the main source of pollutants to northern/northeast region of GB since the second half of the 20 th century have been related to deforestation and landfill and embankment engineering works preformed around the GB, in addition to mineral products applied in industrial goods, as well as oil, agricultural and organic loads. FONTES DE POLUENTES NA AREA NORTE / NORDESTE DA BAIA DE GUANABARA (SE, BRASIL), DESDE O SECULO XIX, COM BASE EM ISOTOPOS DE CHUMBO E CONCENTRACOES DE METAIS Resumo As areas costeiras, as mais populosas do mundo, sao as que tem recebido a maior influencia humana. No litoral sudeste brasileiro, a regiao em torno da Baia de Guanabara (GB), uma das mais densamente povoadas, com grandes cidades, como Rio de Janeiro e Niteroi, e altamente industrializada. Devido as atividades antropicas toneladas de efluentes, residuos e esgoto sao liberados diariamente na GB. Apesar de varios trabalhos terem sido realizados com o objetivo de estudar a influencia humana atual e passada na GB, nao se sabe quais tem sido as fontes de poluentes mais impactantes nesta baia desde o final do seculo XIX. Assim, este trabalho tem como principal objetivo identificar as principais fontes de poluicao na regiao norte / nordeste da GB usando isotopos estaveis de chumbo (Pb) e concentracoes de metais nas ultimas decadas. Analisa os resultados obtidos ao longo do testemunho T3, coletado na regiao nordeste da Baia de Guanabara, proximo a Area Ambiental Protegida de Guapimirim (conhecida como Apa de Guapimirim), uma orla de mangue. Vinte e duas amostras de sedimentos coletadas ao longo deste testemunho foram submetidas a analises granulometricas, teor de carbono orgânico total (COT), concentracoes elementares (Ag, Ca, Cu, P, Pb, S e Zn) e isotopos estaveis de chumbo (Pb). A taxa de acumulacao de sedimentos foi estimada com Pb 210 . Os resultados do testemunho T3 foram comparados com dados semelhantes adquiridos no testemunho T8, coletado na Baia de Guanabara, a norte da ilha de Paqueta. A comparacao dos resultados geoquimicos permitiu verificar que os dois testemunhos registram a mesma realidade. Trabalhos anteriores mostraram que a regiao norte / nordeste da Baia de Guanabara e pouco poluida por metais, no entanto, observou-se nos dois testemunhos que desde 1950 aumentou acentuadamente a eutrofizacao e a concentracao de metais tendo ocorrido um outro pulso de contaminacao depois de 1970. Os valores de 206 Pb / 207 Pb sugerem que as principais fontes de poluentes na regiao norte / nordeste da GB, desde a segunda metade do seculo 20, estiveram relacionadas com o desmatamento e aterros em torno da GB, alem de minerais aplicados em produtos industrias, e ainda petroleo, produtos aplicados na agricultura e materia orgânica. Palavras-chave: Concentracao de metais. Isotopos de Pb. Contaminacao. Fontes de poluicao. Litoral. Registro antropogenico.

This work analyses lead concentrations and isotope ratios 204 Pb, 206 Pb, 207 Pb, 208 Pb, determined by leaching and total dissolution techniques from surface bottom sediment samples collected in the western sector of Sepetiba Bay, Rio de Janeiro (SE Brazil). The main aim of this work was to identify possible sources of Pb, particularly those related to anthropogenic activities for the study area located in the external region of this bay. Isotope ratios of 206 Pb, 207 Pb ranged from 1.160 to 1.259 for the total dissolution technique and from 1.175 to 1.188 for the leaching technique. The Pb isotope signature of the surface sediments of the western sector of Sepetiba Bay were compared with that obtained in other studies performed in Sepetiba Bay, including records of pre- and pos-industrial activity, and in other Brazilian regions. The isotope signature of the analyzed sediments in the western sector of Sepetiba Bay is similar to that obtained in previous works realized in the eastern and northeastern internal region of this bay which is under strong urbanization and industrial pressure. The results of Pb isotope signature obtained by the integrated use of total dissolution and leaching techniques allowed to trace the presence of sediments dredged from highly contaminated areas located in the eastern and north-eastern internal region of Sepetiba Bay probably as a consequence of dredging activities and natural processes of sediment dispersion. IMPACTOS ANTROPOGENICOS NO SETOR OESTE DA BAIA DE SEPETIBA (SE DO BRASIL) ACESSADOS PELA COMPOSICAO ISOTOPICA DE PB DE SEDIMENTOS SUPERFICIAIS Resumo Este trabalho analisa as concentracoes de chumbo (Pb) e isotopos de Pb ( 204 Pb, 206Pb, 207 Pb, 208 Pb) determinados por tecnicas de lixiviacao e dissolucao total de amostras de sedimentos de fundo, coletadas no setor oeste (regiao externa) da Baia de Sepetiba, no Rio de Janeiro (SE Brasil). O principal objetivo deste trabalho foi identificar possiveis fontes de Pb, principalmente aquelas relacionadas a atividades antropogenicas na area de estudo. A assinatura do isotopo Pb dos sedimentos analisados foi comparada com os dados obtidos em outros estudos realizados na Baia de Sepetiba e em outras regioes brasileiras, incluindo registros de atividade pre e pos-industrial. Na regiao externa da Baia de Sepetiba, os valores de 206 Pb/ 207 Pb variaram de 1.160 a 1.259 para a tecnica de dissolucao total e de 1.175 a 1.188 para a tecnica de lixiviacao. A assinatura isotopica dos sedimentos analisados e semelhante a obtida em trabalhos anteriores realizados na regiao interna leste e nordeste desta baia, que esta sob forte influencia da urbanizacao e pressao industrial. Os resultados da assinatura dos isotopos de Pb obtidos pelo uso integrado das tecnicas de dissolucao total e lixiviacao permitiram rastrear, no setor oeste (regiao externa) da Baia de Sepetiba, a presenca de sedimentos provinientes de areas altamente contaminadas localizadas na regiao interna leste e nordeste da baia de Sepetiba, provavelmente como consequencia das atividades de dragagem e processos naturais de dispersao de sedimentos. Palavras-chave: Isotopos de Pb. Geoquimica. Atividades antropogenicas. Fonte de sedimentos. Impacto de dragagem. Litoral.

The section between the 7 and 11 electric markers in the Aratu Stage of the Reconcavo Basin (Lower Cretaceous) has been studied in order to perform a stratigraphic analysis. This section bear reservoir rocks known as Imbe, Cambuqui and Miranga sandstones. It produces petroleum in fields like Miranga, Aracas, Taquipe, Miranga Norte and Imbe. The isopach map showed a general trend of increased subsidence for south and southeast. A series of structural lows surround the platform region known as Quirico High. Southwestward, the Taquipe Canyon is an indication of the lake deepening in that region. In terms of depositional systems, it was interpreted that the Aratu Stage presented a river-dominated deltaic system all over its depositional history. In the proximal regions, located to the north and northwest, the main facies belong to the fluvial and delta plain associations and to the delta front and prodelta in the most distal system. The isolithic map and the sand percentage map indicates a main axial sand distribution. The main sedimentary inflow comes from north and northwest. Near the southeastern faulted border there is a slight contribution from the alluvial fans attached to the Salvador fault. As a natural consequence, the stratigraphic sections showed a decrease of sand south and southeastward as well as the Spontaneous Potential (SP) logs indicate a progressive change from fluvial (normal bell shapes) to deltaic patterns (inverted bell shapes). The sedimentary cyclicity is strongly depicted in the Aratu section. Part of it can be observed in resistivity and SP logs, where auto-correlation can be obtained. Peaks in the resistivity logs indicate lag deposits due to periodic lake flooding. The resistivity value, as a function of the thickness of ostracodal and fish remains calciferous sandstones and shales, allows to separate several orders of peaks (four to six orders). Conventional cyclicity analyses indicate clearly an orbital control due to precession and axial obliquity. The calculated sedimentation ratio is 60 cm/1000 years, and the time interval of 1.44 Ma for deposition of the entire section. ANALISE ESTRATIGRAFICA DO ANDAR ARATU (CRETACIO INFERIOR), BACIA RECONCAVO (BRASIL), COM ROCHAS RESERVATORIO DE HIDROCARBONETOS Este trabalho efetua uma analise estratigrafica da secao entre os marcos eletricos 7 e 11, no Andar Aratu, da Bacia do Reconcavo (Cretaceo Inferior). Esta secao possui rochas reservatorio conhecidas como arenitos de Imbe, Cambuqui e Miranga. Produz petroleo em campos como Miranga, Aracas, Taquipe, Miranga Norte e Imbe. O mapa de isopacas mostrou uma tendencia geral de aumento da subsidencia para o sul e sudeste. Uma serie de baixos estruturais cercam a regiao da plataforma conhecida como a elevacao Quirico. A sudoeste, o canyon de Taquipe constitui uma indicacao do aprofundamento do lago naquela regiao. Os dados obtidos indicam que o Andar Aratu apresentou um sistema deltaico dominado por rio em toda a sua historia deposicional. Nas regioes proximais, localizadas a norte e noroeste, as principais facies pertencem as associacoes fluvial e planicie deltaica, marcando a area mais distal do sistema deposicional, a frente deltaica e o prodelta. O mapas de isolinhas e de percentagem de areia indicam que a distribuicao de areia e sobretudo axial. O principal influxo sedimentar vem do norte e do noroeste. Perto da fronteira com a falha do sudeste ha uma pequena contribuicao de leques aluviais associados a falha de Salvador. Como consequencia natural, as secoes estratigraficas mostraram um decrescimo de areia para sul e sudeste. Os registros geofisicos de Potencial Espontâneo indicam uma mudanca progressiva dos padroes fluviais (em forma de sino) para padroes deltaicos (em forma de sino invertido). A ciclicidade sedimentar e fortemente representada no Andar Aratu. Parte dela pode ser observada nos registros geofisicos de resistividade e de Potencial Espontâneo. Picos nos registros de resistividade indicam inundacoes periodicas do ambiente lacustre. O valor da resistividade, dependente da espessura de arenitos calcarios e xistos com vestigions de ostracodes e peixes, permite separar varias ordens de picos (quatro a seis ordens). Analises de ciclicidade convencionais indicam claramente um controle orbital devido a precessao e obliquidade axial. A taxa de sedimentacao calculada e de 60 cm / 1000 anos, correspondente ao intervalo de tempo de deposicao de toda a secao (andar Aratu) de 1,44 Ma. Palavras-chave: Exploracao de Petroleo. Mapas de Isopacas. Mapas de Isolinhas. Resistividade. Analises de Ciclicidade. Controle Orbital. Sistemas Deposicionais. Sistema Deltaico Dominado por Rio.

The Lu-Hf method has been used in the investigation of geological samples in order to understand processes and sources of magmatic rocks. This paper discusses the reference materials GJ-01, 91.500 and Mud Tank isotopic composition by LA-ICP-MS to investigate how suitable they are for the zircon analysis through this technique. The results show that the three zircons have homogeneous compositions for the proposed objectives. Considering that relatively high Yb contents produce isobaric interference, the results of this work have shown that the Mud Tank is the best reference material, since it has lower values of this element. Thus, the Mud Tank allows to obtain more reliable results due to lower correction requirements. In addition, it should be emphasized that the presented data corroborate the application of Hf isotopes for geological evolution and characterization of magmatic sources. The high abundances of Hf in the zircon grains allow to preserve the isotopic signatures of its crystallization from magmatic sources, allowing to characterize the isotopic signatures of the reservoir (s) that gave origin to that rocks, and in case studies of paleoclimate and paleoceanographic records and/or of sedimentary basins evolution, it allows to identify the origin of the sediments or temporal and spatial changes of the source of sedimentary particles. COMPOSIÇÃO ISOTÓPICA DE Lu, Hf e Yb ANALISADA POR LA-ICP-MS DOS MATERIAIS DE REFERÊNCIA “GJ-01”, “91.500” e “MUD TANK”: APLICAÇÃO DA GEOCRONOLOGIA Lu-Hf EM ZIRCÃO ResumoO método Lu-Hf tem sido utilizado para entender processos de formação e fontes de rochas magmáticas. Este artigo analisa a composição isotópica por LA-ICP-MS dos materiais de referência GJ-01, 91.500 e Mud Tank para investigar quão adequados eles são para a análise de zircônio através desta técnica. Os resultados mostram que os três zircões possuem composições homogêneas podendo ser usados com materiais de referência para as pesquizas referidas. Considerando que teores relativamente altos de Yb produzem interferência isobárica, os resultados deste trabalho mostraram que o Mud Tank é o melhor material de referência, uma vez que possui os menores valores deste elemento. O Mud Tank permite obter resultados mais confiáveis por requerer menor correção dos valores obtidos. Além disso, deve-se ressaltar que os dados apresentados corroboram a aplicação de isótopos de Hf para a evolução geológica e caracterização de fontes magmáticas. As altas abundâncias de Hf nos grãos de zircão permitem preservar as assinaturas isotópicas de sua cristalização a partir de fontes magmáticas, permitindo caracterizar as assinaturas isotópicas do (s) reservatório (s) que deram origem a essas rochas. Têm também utilidade em estudos de paleoclima e paleoceanográficos e/ou da evolução das bacias sedimentares, permitindo identificar a origem dos sedimentos ou mudanças temporais e espaciais da fonte das partículas sedimentares. Palavras-chave: Método Isotópico Lu-Hf. Interferência isobárica. Análise de Alta Resolução Espacial. Zircão. Calibração de materiais de georeferenciamento. Pesquisa analítica.

Paleoenvironmental reconstructions in coastal environments have been carried out using indicators of relative sea level oscillation (RSL), among them, mollusk shells, beachrocks and sedimentary records. Data from eleven geological-geotechnical drilling cores (from 15 m to 30 m long) distributed along the Ipanema - Leblon coastline and on the edge of the Rodrigo de Freitas Lagoon and respective stratigraphic profiles were analyzed in this work. Eleven radiocarbon ages obtained from shell samples calibrated to eliminate the effect of reservoir were used to perform the time evolution of the study area. The obtained results allowed to identify five distinct stages on the sedimentary evolution of the Southern Zone of the Rio de Janeiro City related to the Holocene RSL variations: the first stage under continental environmental conditions, with sea level approximately 4.5 m below the current; the second stage corresponding to a paleo-cove formed due to the sea level rising; the third stage associated with the mid-Holocene maximum transgression, in which the entire study area was flooded; the fourth stage following the gradual lowering of the RSL and marked by the formation of a paleo-bay; the fifth stage corresponding to the current configuration of the coastline. EVOLUCAO E RECONSTITUICAO PALEO-AMBIENTAL DA ZONA SUL DA CIDADE DO RIO DE JANEIRO (SE BRASIL) Resumo As reconstrucoes paleoambientais em ambientes costeiros tem sido realizadas utilizando indicadores de oscilacao relativa do nivel do mar (NRM), entre eles, conchas de moluscos, beachrocks e registros sedimentares. Foram analisados neste trabalho, dados de onze testemunhos de perfuracao geologico-geotecnica (de 15 m a 30 m de comprimento) distribuidos ao longo do litoral de Ipanema - Leblon e a beira da Lagoa Rodrigo de Freitas e respectivos perfis estratigraficos. Onze idades de radiocarbono calibradas obtidas em amostras de conchas foram utilizadas no estudo da evolucao temporal da area de estudo. Os resultados obtidos permitiram identificar cinco etapas distintas da evolucao sedimentar da Zona Sul da cidade do Rio de Janeiro, relacionadas com variacoes do NRM durante o Holoceno: a primeira etapa, sob a influencia de condicoes ambientais continentais, esta relacionada com um nivel do mar aproximadamente 4,5 m abaixo do atual; a segunda etapa corresponde a uma paleo-enseada formada devido a elevacao do nivel do mar; o terceiro estagio associado a transgressao maxima do Holoceno medio, em que toda a area de estudo foi inundada; o quarto estagio, apos o abaixamento gradual do NRM, e marcado pela formacao de uma paleo-baia; a quinta etapa corresponde a configuracao atual do litoral. Palavras-chave: Mudanca relativa do nivel do mar. Quaternario. Sedimentacao Marinha. Evolucao litoral. Modelo 2D.

This work is based on a compilation of benthic foraminiferal data collected in the Aveiro Lagoon and in the adjacent continental shelf and upper slope (center of Portugal). It intends to provide an overall analysis from transitional to the outer continental shelf of the occurrence and distribution of species in living and to present updated taxonomic data and illustrations of most of the species found in the in the Aveiro Lagoon and in the adjacent continental shelf including in total assemblages. Cluster analysis (CA) and Principal Components Analysis (PCA) interpreted as depth functions allow us to identify the main species in different ecoenvironments and sectors of the study area. The most unusual living assemblage was documented in the lagoon inlet under very strong tidal currents activity, composed mostly by the following species (both in living and total assemblages): Rotaliammina concava, Lepidodeuterammina ochracea, Quinqueloculina seminula , Gavelinopsis praegeri , Paratrochammina haynesi, Remaneica helgolandica and Remaneicella gonzalezi. The distribution patterns of some Trochamminidae and Remaneicidae species whose ecology and distribution pattern are poorly known, have proved to be a marker of more or less hydrodynamic and stable/unstable environments in coastal and transitional marine environments. OCORRENCIA DE FORAMINIFEROS E DISTRIBUICAO DAS PRINCIPAIS ESPECIES NA LAGOA DE AVEIRO E NA PLATAFORMA CONTINENTAL ADJACENTE (PORTUGAL) Resumo Este trabalho baseia-se numa compilacao de dados foraminiferos bentonicos recolhidos na Laguna de Aveiro e na plataforma continental adjacente (centro de Portugal). Pretende efetuar uma analise geral da distribuicao de especies nas associacoes vivas e totais (vivas e mortas) na area de estudo, em funcao da profundidade. Pretende ainda apresentar dados taxonomicos e ilustracoes da maioria das especies encontradas na Laguna de Aveiro e na plataforma continental adjacente. A analise de agrupamento (CA) e a analise de componentes principais (PCA), em funcao da profundidade, permitem identificar as principais especies em diferentes ecossistemas e setores da area de estudo. A associacao viva mais invulgar foi encontrada na embocadura da Laguna de Aveiro, um ambiente sujeito a forte corrente de mare. Essa associacao era composta principalmente pelas seguintes especies (na associacao viva e total): Rotaliammina concava, Lepidodeuterammina ochracea, Quinqueloculina seminula , Gavelinopsis praegeri , Paratrochammina haynesi, Remaneica helgolandica and Remaneicella gonzalezi . Os padroes de distribuicao de algumas especies de Trochamminidae e Remaneicidae, cuja ecologia e padrao de distribuicao sao pouco conhecidos, mostraram ser um marcador de ambientes mais ou menos hidrodinâmicos e de estabilidade/instabilidade do substrato em ambientes marinhos costeiros e de transicao. Palavras-chave: Ecologia. Taxonomia. Imagens digitais. Analise Estatistica. Ambientes Transicionais e Costeiros Marinhos.

The postcollisional magmatism in the Ribeira Belt, a collisional Orogen developed through several episodes during the convergence of the Pan-African/Brasiliano Orogeny, was marked in the Eastern Terrane (Rio de Janeiro, SE Brazil) by intense granitic magmatism of Cambro-Ordovician age. This magmatism was previously divided into the Surui and Nova Friburgo suites, both interpreted as I-type granites generated by the interactions of magmas with crustal and mantle origins. This paper presents a new contribution to the understanding of the Sana Granite. It is based on the analysis of field work, mineralogical and geochemical (elemental concentrations by Inductively Coupled Plasma Emission Spectrometer, ICP-ES, and Inductively Coupled Plasma Mass Spectrometry, ICP-MS) data, and U–Pb dating and Lu–Hf isotope analyses, by Laser Ablation Inductively Coupled Plasma Mass Spectrometry (LA-ICP-MS) from the main body and one satellite of the Sana Granite. The results of this work show that the Sana Granite, previously grouped with the Nova Friburgo suite, presents petrographic, geochemical, and isotopic characteristics that do not match its initial petrogenetic interpretation. Data from this work show that the Sana Granite is composed of alkali feldspar granites, syenogranites and monzogranites. All these rocks are hololeucocratic to leucocratic, with small grains ranging from fine to coarse. They are silica-supersaturated, peraluminous, and mostly alkali-calcic rocks and plot at the limit between the ferrous and magnesian fields. Crystallization ages of 480 ± 6 million years (Ma) and 495 ± 4 Ma are obtained in the main body of the Sana Granite, while the ages obtained in the satellite body are 506 ± 10 Ma and 508 ± 5 Ma. The Hf isotope data indicate crustal sources, with depleted mantle model ages (TDM) varying between 2.22 and 1.69 Ga and eHf values ranging between −15.54 and − 6.54. The data set from this work suggests that Sana is an S-type granite formed by the partial melting of metasedimentary rocks from the dehydration of hydrous minerals, such as biotite and muscovite. This massif is composed of muscovite-bearing peraluminous granitoids (MPGs) associated with high-pressure collisional Orogens. Considering that the characteristics of the Sana Granite are incompatible with those of the Nova Friburgo suite, it is proposed to use the Sana suite to characterize S-type granites generated in the postcollisional stage of the Ribeira Belt.

We gathered total organic carbon (%) and relative abundances of benthic foraminifera in intertidal areas and transitional waters from the English Channel/European Atlantic Coast (587 samples) and the Mediterranean Sea (301 samples) regions from published and unpublished datasets. This database allowed to calculate total organic carbon optimum and tolerance range of benthic foraminifera in order to assign them to ecological groups of sensitivity. Optima and tolerance range were obtained by mean of the weighted-averaging method. The data are related to the research article titled "Indicative value of benthic foraminifera for biomonitoring: assignment to ecological groups of sensitivity to total organic carbon of species from European intertidal areas and transitional waters The authors are grateful to the Swiss National Science Foundation, the Agence de l'Eau Artois-Picardie, the Communauté d'Agglomération du Boulonnais, the Université de Lille, the Université du Littoral Côte d'Opale, the Laboratoire d'Océanologie et de Géosciences for their financial support to FOBIMO workshops in Fribourg (Switzerland), Wimereux (France) and Texel (The Netherlands); Additional funding was provided by Spanish MINECO (RTI2018-095678-B-C21, MCIU/AEI/FEDER, UE)

This work sheds light on the recent evolution (≈1915–2015 AD) of Sepetiba Bay (SB; SE Brazil), a subtropical coastal lagoon on the southwestern Brazilian coast, based on a multiproxy approach. Variations in geochemical proxies as well as textural, mineralogical and geochronological data allow us to reconstruct temporally constrained changes in the depositional environments along the SP3 sediment core collected from the central area of SB. At the beginning of the twentieth century, the substrate of the study site was composed of coarse-grained sediments, largely sourced from felsic rocks of proximal areas and deposited under moderate to strong shallow marine hydrodynamics. Since the 1930s, the study area has undergone silting and received high contributions of materials from mafic rocks sourced by river basins. The SP3 core reveals a shallowing-upward sequence due to human-induced silting with significant eutrophication since the middle of 1970, which was caused by significant enrichment of organic matter that was provided by not only marine productivity but also continental and human waste. In addition, the sediments deposited after 1980 exhibit significant enrichment and are moderately to strongly polluted by Cd and Zn. Metals were dispersed by hydrodynamics from the source areas, but diagenetic processes promoted their retention in the sediments. The potential ecological risk index (PERI) indicates that the level of high (considerable) ecological risk is in sediments deposited in ≈1995 (30–32 cm; subsurface). The applied methodology allowed us to understand the thickness of the bottom sediment affected by eutrophication processes and contaminants. Identical methodologies can be applied in other coastal zones, and can provide useful information to decision makers and stakeholders that manage those areas.

International audience; This work contributes to the ongoing work aiming at confirming benthic foraminifera as a biological quality element. In this study, benthic foraminifera from intertidal and transitional waters from the English Channel/European Atlantic coast and the Mediterranean Sea were assigned to five ecological groups using the weighted-averaging optimum with respect to TOC of each species. It was however not possible to assign typical salt marsh species due to the presence of labile and refractory organic matter that hampers TOC characterization. Tests of this study species’ lists with Foram-AMBI on two independent datasets showed a significant correlation between Foram-AMBI and TOC, confirming the strong relation between foraminifera and TOC. For one of the validation datasets, associated macrofaunal data were available and a significant correlation was found between the foraminiferal Foram-AMBI and the macrofaunal AMBI. The here proposed lists should be further tested withsensitivity-based indices in different European regional settings.

Multiproxy approach based on textural, mineralogical, geochemical, and microfaunal analyses on a 176-cm-long core (SP8) has been applied to reconstruct the Holocene paleoenvironmental changes and disentangling natural vs. anthropogenic variability in Marambaia Cove of the Sepetiba Bay (SE Brazil). Sepetiba Bay became a lagoonal system due to the evolution and development of the Marambaia barrier island during the Holocene and the presence of an extensive river basin. Elemental concentrations from pre-anthropogenic layers from the nearby SP7 core have been used to estimate the baseline elemental concentrations for this region and to determine metals enrichment factors (EF), pollution load index (PLI), and sediment pollution index (SPI). Record of the core SP8 provides compelling evidence of the lagoon evolution differentiating the effects of potentially toxic elements (PTEs) under natural vs. anthropic forcing in the last ~ 9.5 ka BP. The study area was probably part of coastal sand ridges between ≈ 9.5 and 7.8 ka BP (radiocarbon date). Events of wash over deposited allochthonous material and organic matter between ≈ 8.6 and 7.8 ka. Climatic event 8.2 ka BP, in which the South American Summer Monsoon was intensified in Brazil causing higher rainfall and moisture was scored by an anoxic event. Accumulation of organic matter resulted in oxygen depletion and even anoxia in the sediment activating biogeochemical processes that resulted in the retention of potentially toxic elements (PTEs). After ≈ 7.8 ka BP at the onset of the Holocene sea-level rise, a marine incursion flooded the Marambaia Cove area (previously exposed to subaerial conditions). Environmental conditions became favorable for the colonization of benthic foraminifera. The Foram Stress Index (FSI) and Exp(H’bc) indicate that the environmental conditions turned from bad to more favorable since ≈ 7.8 ka BP, with maximum health reached at ≈ 5 ka BP, during the mid-Holocene relative sea-level highstand. Since then, the sedimentological and ecological proxies suggest that the system evolved to an increasing degree of confinement. Since ≈ 1975 AD, a sharp increase of silting, Cd, Zn, and organic matter also induced by anthropic activities caused major changes in foraminiferal assemblages with a significant increase of Ammonia/Elphidium Index (AEI), EF, and SPI values and decreasing of FSI and Exp(H’bc) (ecological indicators) demonstrating an evolution from “moderately polluted” to “heavily polluted” environment (bad ecological conditions), under variable suboxic conditions. Thus, core SP8 illustrates the most remarkable event of anthropogenic forcing on the geochemistry of the sediments and associated pollution loads and its negative effect on benthic organisms.

Since the 1960 s, there has been a rapid expansion of drilling activities in the central and northern Adriatic Sea to meet the increasing global energy demand. The discharges of organic and inorganic pollutants, as well as the alteration of the sediment substrate, are among the main impacts associated with these activities. In the present study, we evaluate the response of benthic foraminifera to the activities of three gas platforms in the northwestern Adriatic Sea, with a special focus on the Armida A platform for which extensive geochemical data (organic matter, trace elements, polycyclic aromatic hydrocarbons, other hydrocarbons, and volatile organic compounds) are available. The response to disturbance is assessed by analyzing the foraminiferal diversity using the traditional morphology-based approach and by 18S rDNA-based metabarcoding. The two methods give congruent results, showing relatively lower foraminiferal diversity and higher dominance values at stations closer to the platforms (

This work sheds light on the recent evolution (≈1915-2015 AD) of Sepetiba Bay (SB; SE Brazil), a subtropical coastal lagoon on the southwestern Brazilian coast, based on a multiproxy approach. Variations in geochemical proxies as well as textural, mineralogical and geochronological data allow us to reconstruct temporally constrained changes in the depositional environments along the SP3 sediment core collected from the central area of SB. At the beginning of the twentieth century, the substrate of the study site was composed of coarse-grained sediments, largely sourced from felsic rocks of proximal areas and deposited under moderate to strong shallow marine hydrodynamics. Since the 1930s, the study area has undergone silting and received high contributions of materials from mafic rocks sourced by river basins. The SP3 core reveals a shallowing-upward sequence due to human-induced silting with significant eutrophication since the middle of 1970, which was caused by significant enrichment of organic matter that was provided by not only marine productivity but also continental and human waste. In addition, the sediments deposited after 1980 exhibit significant enrichment and are moderately to strongly polluted by Cd and Zn. Metals were dispersed by hydrodynamics from the source areas, but diagenetic processes promoted their retention in the sediments. The potential ecological risk index (PERI) indicates that the level of high (considerable) ecological risk is in sediments deposited in ≈1995 (30-32 cm; subsurface). The applied methodology allowed us to understand the thickness of the bottom sediment affected by eutrophication processes and contaminants. Identical methodologies can be applied in other coastal zones, and can provide useful information to decision makers and stakeholders that manage those areas.

Heavy metals are one of the most hazardous pollutants in marine environments because of their bioaccumulation and biomagnification capabilities. Among them, cadmium (Cd) has been considered as one of the most dangerous for marine organisms. Here we incubated Ammonia cf. parkinsoniana specimens, a benthic foraminiferal taxon used in previous experiments, for up to 48 h in natural seawater with different concentrations of Cd to unravel the physiological change. We document a reduced pseudopodial activity of the Cd-treated specimens at concentrations &gt, 10&ndash, 100 ppb in comparison with the control specimens. Moreover, confocal images of Cd-treated specimens using Nile Red as a fluorescent probe reveal an enhanced intracellular neutral lipid accumulation in the form of lipid droplets at 6 h and 12 h. This bioassay experiment allows for the direct evaluation of Cd-dose to A. cf. parkinsoniana-response relationships under laboratory controlled conditions and provides complementary information to field observations as well as to water quality guidelines and thresholds.

This study provides a comparison between living (LAs) and dead (DAs) assemblages of benthic foraminifera in 137 sites located at the mouth region of the Aveiro Lagoon (N Portugal). This coastal lagoon, commonly named Ria de Aveiro, is under strong anthropogenic influence due to changes in natural hydrodynamics through engineering structures and by the input of contaminants. The sedimentary environments of the mouth area are characterized by biotic (benthic foraminifera) and sedimentological (grain size, trace metals and total organic carbon concentrations) data. The pollution load index (PLI) identifies areas of increased concentrations of potentially toxic trace metals. An innovative combination of several statistical methods and extremely detailed data analyses allowed to verify that the dead associations (DAs) and the living assemblages (LAs) are absent or reduced in the deep and most hydrodynamically active zones along the navigable waterways of the channels. Breakwaters reducing the bottom currents allow the development of larger and more diversified LAs. The most suitable areas for LAs are located close to the South Jetty and in Mira Channel excluding the navigable channel and the eastern margin. LAs have in general little similarity with the DAs. Confined zones and areas with high organic matter flux and trace metals concentrations, where the sediments are being accumulated, are particularly unfavourable environments for living foraminifera. The obtained results evidenced that marked differences in hydrodynamics determine large dissimilarities between LAs and DAs. In some environments the taphonomic effects caused by the removal and high accumulation of foraminiferal tests can significantly misrepresent the faunal composition in the fossil registry, and lead to misinterpretations about the paleoenvironmental evolution.

This study characterizes the quantity and quality of organic matter present in surface sediments of the NE sector of Guanabara Bay (SE, Brazil), based on geochemical and statistical analysis. The geochemical analyses included stable isotopes in sedimentary bulk organic matter (orgδ13C), total organic carbon (TOC), total sulfur (TS) and Rock Eval pyrolysis parameters, such as free hydrocarbons (S1), generating source potential (S2), production index (PI), oxygen and hydrogen indices (OI, HI) and the maturation index of organic matter (Tmax). The analyzed data were statistically treated to find main factors that are influencing the sedimentary composition. The low activity of the bottom currents favors the deposition of fine-grained sediments, rich in organic matter, in most of the studied area. The organic matter present in the sediments is being supplied by local and allochthonous sources and can be considered a good source of type III kerogen, and therefore has the potential to generate gas, if the geological context is adequate. Considering the quantity, type of organic matter and potential of hydrocarbon generation four main groups of stations were identified. Stations in which the sediments: i) encompass a relatively high component of OM sourced mainly from the adjacent continental areas close to the Apa de Guapimirim (less contaminated by oil) and S. Gonçalo (Roncador River) regions; ii) contain some autochthonous contribution, located between the Paquetá and Governador Islands, where biogenic gas seeping should be predicted hereafter; iii) have higher contamination by oil, situated near Mauá and REDUC Oil Refinery, of Duque de Caxias; iv) present intermediate characteristics, located in the remaining study area. ResumoEste estudo efetua a caracterização da quantidade e qualidade da matéria orgânica presente em sedimentos superficiais do setor NE da Baía de Guanabara (SE, Brasil), com base em análises geoquímicas e estatísticas. Os dados geoquímicos incluíram isótopos estáveis em matéria orgânica (ORGδ13C), carbono orgânico total (TOC), enxofre total (TS) e parâmetros de pirólise Rock Eval, como por exemplo, teores se hidrocarbonetos livres (S1), potencial de geração hidrocarbonetos (S2), índice de produção (PI), índices de oxigênio e hidrogênio (OI, HI) e índice de maturação da matéria orgânica (Tmax). Os dados analisados foram tratados estatisticamente a fim de serem identificados os principais fatores que influenciam a composição sedimentar. A fraca atividade das correntes de fundo, favorece a deposição de sedimentos finos ricos em matéria orgânica, na maior parte da área estudada. A matéria orgânica presente nos sedimentos está sendo fornecida por fontes locais e alóctones e pode ser considerada uma boa a excelente fonte de querogênio do tipo III, tendo, pois, potencial para a geração de gás, desde que o contexto geológico seja adequado. Considerando-se a quantidade, o tipo de matéria orgânica e o potencial de geração de hidrocarbonetos podem ser identificados quatro grupos principais de estações. Estações em que os sedimentos: i) possuem teores relativamente elevados de matéria orgânica oriunda principalmente das áreas continentais, localizadas próximo da Apa de Guapimirim (menos contaminadas por petróleo) e S. Gonçalo (Rio Roncador); ii) contêm alguma contribuição autóctone, situadas entre a Ilha de Paquetá e a Ilha do Governador, onde se poderá prever a ocorrência de libertação de gás biogênico num futuro próximo; iii) possuem maior contaminação por petróleo, localizadas próximo de Mauá e da refinaria Reduc, de Duque de Caxias; iv) apresentam características intermédias, situadas na restante área de estudo.

This study characterizes the quantity and quality of organic matter present in surface sediments of the NE sector of Guanabara Bay (SE, Brazil), based on geochemical and statistical analysis. The geochemical analyses included stable isotopes in sedimentary bulk organic matter (orgδ13C), total organic carbon (TOC), total sulfur (TS) and Rock Eval pyrolysis parameters, such as free hydrocarbons (S1), generating source potential (S2), production index (PI), oxygen and hydrogen indices (OI, HI) and the maturation index of organic matter (Tmax). The analyzed data were statistically treated to find main factors that are influencing the sedimentary composition. The low activity of the bottom currents favors the deposition of fine-grained sediments, rich in organic matter, in most of the studied area. The organic matter present in the sediments is being supplied by local and allochthonous sources and can be considered a good source of type III kerogen, and therefore has the potential to generate gas, if the geological context is adequate. Considering the quantity, type of organic matter and potential of hydrocarbon generation four main groups of stations were identified. Stations in which the sediments: i) encompass a relatively high component of OM sourced mainly from the adjacent continental areas close to the Apa de Guapimirim (less contaminated by oil) and S. Gonçalo (Roncador River) regions; ii) contain some autochthonous contribution, located between the Paquetá and Governador Islands, where biogenic gas seeping should be predicted hereafter; iii) have higher contamination by oil, situated near Mauá and REDUC Oil Refinery, of Duque de Caxias; iv) present intermediate characteristics, located in the remaining study area.

The use of geochemical normalizers has been applied in sedimentological studies in several study contexts, such as pollution, diagenetic and provenance assessment. Selected textural and mineralogical data of 137 surface sediment samples were compared by statistical analyses with geogenic elements concentrations normalized by the Al, Be, Ce, Fe, Fe+Al, Li, Rb and Sc aiming to identify the best normalizer to trace different sources of bottom sediments for the Aveiro Lagoon entrance (NW of Portugal). The study area is heterogenous in terms of hydrodynamics and sedimentary processes.The most commonly applied geochemical normalizer for the sediments elemental concentrations has been the aluminum. However, the statistical analyses evidenced that the best normalizer was the scandium, since Principal Components Analysis results have evidenced that the element/Sc values are largely independent of sediment granulometry and thus have allowed the identification of compositional differences not related to grain size. Statistical analyses have also allowed to discriminate groups of stations that: i) trace the entry and exit of mixed sources sediments of the lagoon due to the action of tidal currents; ii) contain materials provided from the erosion of granitoids present mainly along the Douro River basin, located to the north, and transported southward by coastal drift; iii) encompasse sediments provided from the erosion of the Schist–Greywacke Complex crossed by the Vouga River that drains into the inner central zone of the lagoon and; iv) represent an area of sediment accumulation located near the entrance of Mira Channel, where lithogenic materials, provided by mixed lithologies in addition to organic matter, are being deposited. The results of this work contribute to the knowledge of the sedimentary dynamics of the Aveiro Lagoon, a coastal system which is part of a littoral stretch that is being strongly eroded, due to natural and anthropic causes and should be applicable to other coastal systems with similar characteristics. ResumoO uso de normalizadores geoquímicos tem sido aplicado em estudos sedimentológicos em diversos contextos, como por exemplo, de poluição, avaliação diagenética e de proveniência de sediments. Dados texturais e mineralógicos selecionados de 137 amostras de sedimentos superficiais foram comparados através de análises estatísticas com concentrações de elementos geogênicos normalizadas por Al, Be, Ce, Fe, Fe + Al, Li, Rb e Sc. O estudo visou identificar o melhor normalizador para traçar diferentes fontes de sedimentos de fundo para a entrada da Lagoa de Aveiro (NW de Portugal), uma área heterogênea em termos de processos hidrodinâmicos e sedimentares.O normalizador geoquímico mais comumente aplicado em sedimentos tem sido o alumínio. No entanto, as análises estatísticas evidenciaram que o melhor normalizador foi o escândio, uma vez que os resultados da análise de componentes principal evidenciaram que os valores das razões elemento/Sc são amplamente independentes da granulometria sedimentar e permitiram a identificação de diferenças composicionais não relacionadas com o tamanho do grão. Análises estatísticas também permitiram discriminar grupos de estações que: i) traçam a entrada e saída de fontes mistas de sedimentos da laguna, devido à ação das correntes de maré; ii) contêm materiais provenientes da erosão de granitóides presentes principalmente ao longo da bacia do Rio Douro, localizada a norte, e transportados para sul por deriva litoral; iii) contêm sedimentos provenientes da erosão do Complexo Xisto-grauvaquico atravessado pelo Rio Vouga, que desagua na zona central interna da laguna e; iv) representam uma área de acumulação de sedimentos localizada perto da entrada do Canal Mira, onde materiais litogênicos, fornecidos por litologias diversificadas, além de matéria orgânica, estão sendo depositados.Os resultados deste trabalho contribuem para o conhecimento da dinâmica sedimentar da Laguna de Aveiro, um sistema costeiro que faz parte de um trecho litorâneo fortemente erodido, devido a causas naturais e antrópicas and may be applicable to other coastal systems with similar characteristics.

The use of geochemical normalizers has been applied in sedimentological studies in several study contexts, such as pollution, diagenetic and provenance assessment. Selected textural and mineralogical data of 137 surface sediment samples were compared by statistical analyses with geogenic elements concentrations normalized by the Al, Be, Ce, Fe, Fe+Al, Li, Rb and Sc aiming to identify the best normalizer to trace different sources of bottom sediments for the Aveiro Lagoon entrance (NW of Portugal). The study area is heterogenous in terms of hydrodynamics and sedimentary processes. The most commonly applied geochemical normalizer for the sediments elemental concentrations has been the aluminum. However, the statistical analyses evidenced that the best normalizer was the scandium, since Principal Components Analysis results have evidenced that the element/Sc values are largely independent of sediment granulometry and thus have allowed the identification of compositional differences not related to grain size. Statistical analyses have also allowed to discriminate groups of stations that: i) trace the entry and exit of mixed sources sediments of the lagoon due to the action of tidal currents; ii) contain materials provided from the erosion of granitoids present mainly along the Douro River basin, located to the north, and transported southward by coastal drift; iii) encompasse sediments provided from the erosion of the Schist–Greywacke Complex crossed by the Vouga River that drains into the inner central zone of the lagoon and; iv) represent an area of sediment accumulation located near the entrance of Mira Channel, where lithogenic materials, provided by mixed lithologies in addition to organic matter, are being deposited. The results of this work contribute to the knowledge of the sedimentary dynamics of the Aveiro Lagoon, a coastal system which is part of a littoral stretch that is being strongly eroded, due to natural and anthropic causes and should be applicable to other coastal systems with similar characteristics.

Nine crab species samples, males and females, were collected after homogeneously prospection of sediment surface of Bizerte Lagoon. Crabs were caught by dip net from Bizerte Lagoon during spring 2012. Concentrations of metals (Zn, As, Cd, Cr, Cu, Fe, Ni, Pb and Zn) were evaluated in the carapace and muscle tissue of crabs and in surface sediment samples. Concentrations of metals accumulated in the benthic crabs tissues were compared to the reactive metals content that constitute the bioavailable fraction of the sediments. Total organic carbon and carbonate contents were also determined, since they are principal requirements associated with crab development. Results of this work indicate that, in the study area, the metals that reach the highest concentrations in the sediments-water interface are by decreasing order Zn, Cr and Pb. The reactive concentrations of these metals are also the highest. However, the trace elements that are being accumulated in the carapace and muscle of crabs are mainly As and Cu. Continental waters flowing into the Bizerte Lagoon are the main source and the principal cause of the enrichment of trace elements in sediment. Results highlight that the reactive concentrations of metals in sediments were the principal cause of their bioaccumulation in the crabs tissues. The important results of this work highlight that cabs can be very useful on studies of monitoring and evaluation of environmental quality in addition to data obtained from the sediment as they also give information about the bioaccumulation of metals through the oceanic food webs. Resumo Nove amostras de especies de caranguejos, machos e femeas, foram coletadas na superficie do sedimento da Laguna de Bizerte. Os caranguejos foram capturados com uma rede na Laguna de Bizerte, na primavera de 2012. Foram avaliadas nas carapacas e no tecido muscular dos caranguejos e em amostras de sedimentos superficiais, concentracoes de metais (Zn, As, Cd, Cr, Cu, Fe, Ni, Pb e Zn). As concentracoes de metais acumuladas nos tecidos de caranguejos benticos foram comparadas com o teor de metais reativos que constituem a fracao biodisponivel dos sedimentos. Os teores totais de carbono orgânico e carbonato tambem foram determinados, uma vez que sao requisitos principais associados ao desenvolvimento dos caranguejos. Os resultados deste trabalho indicam que, na area de estudo, os metais que atingem as maiores concentracoes na interface sedimentos-agua sao, por ordem decrescente, Zn, Cr e Pb. As concentracoes reativas desses metais tambem sao as mais elevadas. No entanto, os metais que estao sendo acumulados nas carapacas e nos musculos dos caranguejos sao principalmente As e Cu. As aguas continentais que desembocam na Laguna Bizerte sao a principal fonte e a principal causa do enriquecimento de metais nos sedimentos. Os resultados sugerem que as concentracoes reativas de metais nos sedimentos foram a principal causa de sua bioacumulacao nos tecidos dos caranguejos. Os resultados deste trabalho revelam que para alem dos dados sedimentologicos, os caranguejos podem ser muito uteis em estudos de monitoramento e avaliacao da qualidade ambiental, pois fornecem informacoes sobre a bioacumulacao de metais atraves das cadeias alimentares oceânicas.

The main environmental variables controlling benthic foraminiferal distributions were identified and used to assess their influence on ecological indices developed as predictors of Ecological Quality Status (EcoQS) in marine ecosystems. Gradient forest and random forest models were applied to assess the predictive value of a selection of abiotic (environmental) and biotic (foraminifera) variables in a costal marine area in the central Adriatic Sea (Italy). This approach yields evidence that the predictor variables sand, silt, Pollution Load Index, and TN have the greatest influence on the distribution of benthic foraminifera in this area. In addition, we identify thresholds for the most important environmental variables that influence ecological indices. These findings contribute to efforts to determine how to best improve sediment quality and environmental stability for marine conservation. Further application of these approaches represents a useful tool for policymakers to survey the diversity of marine organisms and to improve the ability to protect and restore marine ecosystems by identifying predictors of diversity and identifying key thresholds in these predictors.

International audience; Dredging is a common and important activity to maintain or improve/extend navigable depths in many ports and harbours. Dredging sometimes occur in areas where the sediments are contaminated material and is subject to consent and licensing according to the national regulations. This work shows the general pattern of distribution of potentially toxic elements (PTEs), such as As, Cd, Co, Cr, Cu, Ni, Pb and Zn, in surface sediments of the Ria de Aveiro lagoon mouth area (Portugal). The work is based on textural, mineralogical and geochemical analysis of 137 surface sediment (first centimetre) samples. The Pollution Load Index (PLI) was used to evaluate the overall enrichment of these elements and the enrichment factor (EF) was determined to assess the degree of anthropogenic input of taking into account the characteristics of the receiving environment and its legitimate use; and one station (29) as slightly contaminated dredged material (Class 3) that may be used for embankments or in the case of soaking requires a thorough study of the place of deposition and subsequent PTEs. Portuguese Ministerial Order n.° 1450/2007 was used as reference to classify dredging and elimination or application of dredging materials. Results evidence that the study area, which is highly anthropized, the concentration of PTEs is largely controlled by the hydrodynamics. The PLI index values show the highest enrichment of metals in the western side of Mira Channel entrance. The EF values indicate that eighty-three stations have significant enrichment of metals particularly Pb and Cr being the significant enrichment by Cr much more common and by Pb punctually. According to the Portuguese regulation most of the sites can be classified as clean dredged material (Class 1), sixteen sites as dredged material with trace contamination (Class 2) that may be immersed in the aquatic environment monitoring. In addition, sediments have an important ecological value.

This work intends to apply new ecological descriptors to a coastal marine area aiming to assess its environmental trophic status. This approach make possible to identify relevant variables associated with eutrophication process applicable and valid worldwide. The aim of this work is to study the organic matter (OM) quality and quantity, in terms of biopolymers, in Saquarema Lagoonal System (SLS) located in Rio de Janeiro State (Brazil). Sediment samples collected in SLS were analyzed in this study for granulometric and geochemical data such as total organic carbon (TOC), total sulfur (TS) and biopolimeric carbon (BPC) concentration, including proteins (PTN), carbohydrates (CHO) and lipids (LIP). These data were combined with additional environmental parameters measured in water of the four linked lagoons that compose the SLS. Data analyses allowed the identification of four distinct regions in SLS: an inner and impacted zone characterized by sediment particularly enriched in TOC, with lowest quality of OM most probably provided by contaminated effluents and rivers runoff; an outer-less impacted lagoonal area with relatively low TOC content and submitted to high hydrodynamic forces; an intermediate area characterized by transitional features between the two previously mentioned and a zone that are influenced mainly by salinity. The organic matter accumulation depends on the hydrodynamic conditions mostly governed by tidal currents. The quality of organic matter seems to be mainly influenced by the water renewal, rivers inputs and mangroves contributions as well as by the autochthonous lagoonal biological productivity. Results of this work indicate that the inner zone of SLS is being affected by eutrophication not necessarily caused by anthropic factors.

In the Godineau River Estuary, located in Trinidad Island (off the northeast coast of Venezuela), were found 114 taxa of foraminifera and 17 of thecamoebians in the dead fauna. Most of the identified foraminiferal species were rare because they were transported from the Gulf of Paria to this estuary. The autochthonous foraminiferal assemblage was represented by several tropical estuarine species such as Ammonia tepida, Ammotium salsum, Arenoparrella mexicana, Cribroelphidium excavatum, Ammonia parkinsoniana, Haplophragmoides wilberti, Miliammina fusca and Ammotium cassis. The thecamoebians assemblages, found in the inner part of this estuary, were dominated by Cyclopyxis spp., Centropyxis spp., Difflugia corona and Difflugia urceolata. The relative abundance of the main species of foraminifera and thecamoebians were analyzed through Q-mode and R-mode cluster analyses. Statistical results revealed the presence of three different environments in the Godineau River Estuary related to different hydrodynamic conditions and more or less oceanic or fluvial influence. The first sector represents the most confined region of the estuary and was mainly composed by agglutinated foraminifera together with thecamoebians. The second sector was located in the middle part of the estuary and was associated with the presence of brackish waters. The third sector denotes the outermost part of the estuary characterized by the greatest hydrodynamic activity and highest oceanic influence within the estuary. This sector was marked by the occurrence of a large number typical-marine foraminifera species.

Core T4 (with 286 cm long) collected in the inner part of Sepetiba Bay is a record of late Holocene evolution of Sepetiba Bay. This core was described and sampled every 2 cm. Textural, geochemical and foraminifera data were analyzed, and two radiocarbon dates were obtained. Estimated ages indicate that core T4 represents the last ≈4,000 years calibrated before present (yrs cal BP). Results of this core suggest that coarse sediments, recorded in the period between ≈4,000-3,400 yrs cal BP, were probably associated with high hydrodynamic conditions in the study area. These sediments should be deposited at an incipient phase of the Marambaia Beach Barrier evolution; the development of this sand barrier resulted in the confinement of the inner region of Sepetiba Bay, leading to the deposition of muddy sediments rich in organic matter. Organic matter enrichment increased especially in the last ≈500 yrs cal BP. Foraminifera assemblages and carbonates content indicate that the studied region should have been affected in the last ≈3,400 yrs cal BP by changes in the water depth column. An increase of the water column depth was recorded for example between ≈850-350 yrs BP. The results obtained in the core T4 show that the confinement and eutrophication process of the internal zone of Sepetiba Bay, has been occurring since ≈3,400 yrs cal BP and is being caused by other factors such as geomorphological and climatic changes and human activities.

This study intends to evaluate baseline concentrations of chemical elements for unpolluted sediments of Sepetiba Bay (SE Brazil). It analyzes the concentrations of potentially toxic elements (PTE) and other chemical elements (by Inductively Coupled Plasma Mass Spectrometry and Inductively Coupled Plasma Emission Spectrometry) from the upper part of the SP2 drillcore (or 2-SPT-1-RJ; with 50.30 m length), collected on the margins of Sepetiba Bay (at latitude 22° 55'S and longitude 43° 46'W). This core was described and sampled. Textural, mineralogical and geochemical analyses were performed in 17 sediment levels. The sediment layers of interest were selected, considering the period in which they were deposited, before high anthropic influence in the area, and on sediment grain-size. Only the muddy levels were selected, since fine sediments generally tend to have higher elemental concentrations. Foraminiferal occurrence was also analyzed in the selected layers. The results indicate that the studied sediments were deposited in a transitional marine context, after being exposed to multiple sedimentary cycles and weathering. The baseline concentrations, related to natural sediment sources were estimated for As, Cd, Co, Cr, Cu, Ni, Pb, Zn) and P and for other chemical elements. These results are useful in environmental impact assessment not only in the study area, but also for other coastal regions of Rio de Janeiro State. TÍTULO: CONCENTRAÇÕES DE FUNDO DE ELEMENTOS QUÍMICOS NA BAÍA DE SEPETIBA (SE BRASIL) RESUMO:Este estudo pretende avaliar as concentrações de fundo de elementos químicos, em sedimentos não poluídos, na Baía de Sepetiba (Se Brasil). Analisa as concentrações de elementos potencialmente tóxicos (PTE) e outros elementos químicos (por Espectrometria de Massa Plasma Acoplada Indutivamente e Espectrometria de Emissão Plasma Acoplada Indutivamente) da parte superior do testemunho SP2 (ou 2-SPT-1 RJ; com 50,30 m de comprimento), coletado nas margens da Baía de Sepetiba (à latitude 22° 55'S e longitude 43° 46'W). Este testemunho foi descrito e amostrado a cada 5 cm. Análises estruturais, mineralógicas e geoquímicas foram realizadas em 17 níveis de sedimentos. Os níveis de interesse foram selecionados, considerando o período em que foram depositados, antes da alta influência antrópica na área, e no tamanho do grão do sedimento. Apenas os níveis de lama foram selecionados, uma vez que os sedimentos finos tendem geralmente a ter maiores concentrações de elementos quimicos. A ocorrência de foraminíferos foi também analisada nas camadas selecionadas. Os resultados indicam que os sedimentos estudados foram depositados num contexto marinho de transição, após serem expostos a múltiplos ciclos sedimentares e a intemperismo. As concentrações de fundo, relacionadas a fontes naturais de sedimento foram estimadas para As, Cd, Co, Cr, Cu, Ni, Pb, Zn) e P e para outros elementos químicos. Esses resultados são úteis para a avaliação de impacto ambiental, não apenas na área de estudo, mas também em outras regiões costeiras do Estado do Rio de Janeiro. PALAVRAS-CHAVE: Multi-indicadores. Sedimentos. Registros Holocénicos. Litoral. Atlântico Sul.

This study investigates and compares the seasonal variations during winter and summer of living benthic foraminiferal assemblages in the Saquarema Lagoon System (SLS) located in a tropical coastal region of SE Brazil. The physicochemical parameters in the SLS presented strong differences between both seasons; however, they remained quite homogeneous in winter and exhibited great oscillations in summer. In the study area, 29 and 19 living foraminiferal species were identified in summer and winter, respectively. Ammonia tepida was the dominant species in both seasons followed by Ammonia parkinsoniana and Cribroelphidium excavatum. The detrended correspondence analysis showed that in the SLS: the calcareous species, such as Adelosina carinatastriata, Bulimina patagonica, and Miliolinella antartica were mostly influenced by high dissolved oxygen contents and low temperature, whereas the agglutinated foraminiferal species were indicators of the most confined lagoonal areas, under the lowest pH and salinity values. The results of this work evidence that the seasonal variation in the SLS might play a more important role in the benthic foraminiferal assemblages’ distribution than the anthropogenic impacts and shows the importance of seasonal studies for coastal biomonitoring programs.

The distribution of living (rose Bengal stained) Reophax pyriformis Yamashita, Sousa and Kaminski, n. sp., an agglutinated benthic foraminiferal species, was analyzed in the area of the Campos Basin (southeastern Brazilian continental margin). The study is based on 34 oceanographic stations (54 samples), located between 400 m and 3000 m water depth. The distribution of living R. pyriformis n.sp. density is compared to sedimentological parameters, such as total organic carbon, total nitrogen, calcium carbonate, phytopigment, lipids biomarkers (sterols, fatty acids and n-alcohols), total lipids, and bacterial biomass, as well as the particulate organic matter flux to the seafloor. This species was found in the range of 1000–1200 m water depth, with an average living depth of 1.52 cm in the sediment. The distribution of this species seems to be related to lipid biomarkers (allochthone and/or continental derivative, zooplankton and/or fauna, phytoplankton or primary producers) and total organic carbon under the influence of Intermediate Western Boundary Current conditions.

The disposal of waste and sewage by anthropic activities in Guanabara Bay (GB), Rio de Janeiro State (Brazil) is negatively affected this coastal ecosystem over the last few decades. This research intends to document how organic matter and metal enrichment affect the benthic organisms. Physicochemical, textural, geochemical and microfaunal data (foraminifera) are analyzed in nine stations in the NE sector of Guanabara Bay. The size and structure of the living foraminiferal assemblages are analyzed on each sedimentary fractions (63-150 μm, 150-250 μm, 250-500 μm and >500 μm) of every station. In the fraction >500 μm no foraminifera were found. Results suggest that organic matter contents are high everywhere whereas metals concentrations increase in Sao Goncalo region. The dimension, diversity and equitability of the living foraminiferal assemblages were reduced in the study area. Ammonia tepida was the dominant taxon in all samples. Living specimens identified in the 63-150 μm sedimentary fraction were found at all stations except in front of Sao Goncalo city (stations GB9 and GB8). Most of species were not found in the 250-500 μm sediment fraction in most sites except for instance Ammonia tepida . This species dominate in eutrophic areas but where organic matter is in an oxide stage and regardless of whether there is or not gas seep. Foraminiferal density and diversity increased in areas with a prevalence of organic matter from oceanic biological production and declined in areas where organic matter and metals are retained in disoxic/anoxic phases of the sediments.

This work was performed in the NE region of the Guanabara Bay, a highly impacted Brazilian coastal system, located in Rio de Janeiro State. It aimed to: i) identify and map the areas with occurrence of gas in the sediment, as well as its acoustic signature; ii) characterize the physical properties of the sediments and; iii) document the response of microbenthic organisms (living benthic foraminifera) to changes in quantity and quality of organic matter. Seismic surveys at the frequency of 12 kHz identified a large area with about 50% gas charged sediments in the study area. The main acoustic signatures of the shallow gas were black shadow and gas blanket. In addition, features related to gas seepages to the water column (acoustic plumes and pockmarks) and gas percolation within the sediments (intra-sedimentary plumes, turbidity pinnacles) were also identified. The gas has a biogenic origin and results from the high sedimentation rate between 0.03 to 0.9 cm.year -1 and from the decomposition of large amount of organic matter (10-20%). Vertical distribution of gas ranges from few centimeters to 9 m below the water-sediments interface. These occurrences are related to both gas migration from lower sedimentary layers to Holocene muds above, and to recent generation in near-surface sediments as the area display favorable conditions for gas production. Cores ranging from 150-240 cm in length have predominantly muddy sediments and variations in the P-wave velocity followed the changes in sediment density, controlled mainly by the presence of gas in sediments, bioclasts accumulation, textural variation and percentage of organic matter. The TOC content and Rock-Eval pyrolysis parameters evaluated in nine surface sediment samples indicate that good to excellent amount of organic matter associated with moderate to good source potential for gas production is present in the study area. In these areas living benthic foraminifera are of reduced diversity and density. The assemblages are largely dominated by Ammonia tepida . Statistical results evidence that areas of intense gas release affect the benthic faunas since the benthic foraminiferal assemblages are reduced in diversity and density.