Assessing man-induced environmental changes in the Sepetiba Bay (Southeastern Brazil) with geochemical and satellite data

Araújo, Daniel F.; Peres, Lucas Garcia Magalhães; Yépez, Santiago; Mulholland, Daniel Santos; Machado, Wilson; Tonhá, Myller S.; Garnier, Jérémie

doi:10.1016/j.crte.2017.09.007

Cited by 38 publications

(16 citation statements)

References 35 publications

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“…With characteristics of a semi-confined lagoon, Sepetiba Bay is bounded at north by the continent, at east by Guaratiba tidal plain, at south by Marambaia Sand Ridge as well as a string of migmatitic islands (Suguio et al, 1979;Brönnimann et al, 1981;Roncarati and Carelli, 2012;Villena et al, 2012;Araújo et al, 2017). The communication between Sepetiba Bay and the ocean occurs at the western mouth, between the mainland and the Marambaia Sand Ridge, and to the east, to a lesser extent, through the Guaratiba Channel.…”

Section: Study Areamentioning

confidence: 99%

“…The expansion of economic and industrial activities along the coastal areas have unquestionably introduced metals into marine sediments (Muniz et al, 2004;Wolanski and McLusky, 2011). Such input of metals represents a serious socio-environmental problem, since coastal regions constitute an important source of food and other resources for the populations that inhabit them (Araújo et al, 2017). Potentially dangerous trace elements are brought to the marine environment by the direct discharge of urban waste and industrial effluents and can be transported through the atmosphere from their source to coastal locations (Cardoso et al, 2001;Kasilingam et al, 2016).…”

Section: Introductionmentioning

confidence: 99%

“…The geochemical backgrounds from marine sediments, provide an approach on the present environmental quality of the ecosystem, but also serve as a baseline for future investigations (Kasilingam et al, 2016). Due to the growing urbanization rate and fast and unplanned development, many tropical coastal areas in Brazil are being affected by accelerated processes of ecosystems degradation (Gomes et al, 2009;Araújo et al, 2017). In southeastern Brazil, the Sepetiba Bay is suffering environmental disturbances due to anthropic activities (e.g.…”

Section: Introductionmentioning

confidence: 99%

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Background Concentrations of Chemical Elements in Sepetiba Bay (Se Brazil)

et al. 2019

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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.

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Section: Study Areamentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Background Concentrations of Chemical Elements in Sepetiba Bay (Se Brazil)

et al. 2019

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“…The most pronounced oxygen scarcity, and the establishment of anoxia, at least in micro environments, may have occurred for example in the first 60 cm of the sedimentary column (new sediments) and in the section 240-126 cm depth, leading to the production of biogenic pyrite (Fig. 4), as also observed by Araújo et al (2017). In the lower core section, the establishment of anoxic conditions should have not been contemporary of the sediment deposition.…”

mentioning

confidence: 68%

“…The reduction of Zn, Ni, Co and Cd in this section (≈126-0 cm), is the opposite of what we were expecting. Several previous works revealed the occurrence of sharp increase of metals in the last century caused by the exponential population growth and industrial activity around Sepetiba Bay (Silva-Filho et al, 1996;Wasserman et al, 2001;Gomes et al, 2009;Patchineelam et al, 2011;Borges and Nittrouer, 2016;Araújo et al, 2017).…”

Section: Sedimentary Record Loss In Core Sp6mentioning

confidence: 99%

Impact of Eutrophication on Benthic Foraminifera in Sepetiba Bay (Rio De Janeiro State, Se Brazil)

et al. 2019

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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; 210Pb and 137Cs; 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 EUTROFICAÇÃO EM FORAMINIFEROS BÊNTONICOS NA BAÍA DE SEPETIBA (ESTADO DO RIO DE JANEIRO, SE BRASIL) ResumoO principal objetivo deste trabalho é analisar as conseqüências da eutrofização em organismos meiofaunais bentônicos (foraminíferos) em uma área interna da Baía de Sepetiba (Estado do Rio de Janeiro, SE, Brasil). Este estudo é interessante porque, no local estudado, os sedimentos correspondentes ao período de maior acumulação de matéria orgânica, não estavam contaminados por metais, apesar da Baía de Sepetiba ter áreas reconhecidamente poluídas por este tipo de contaminantes. Assim neste estudo foi possível considerar apenas o impacto causado pela eutrofização.No testemunho SP6, coletado na área interna da Baía de Sepetiba e estudado neste trabalho, foram analisados dados texturais, geoquímicos (concentração de elementos químicos; 210Pb e 137Cs; dados de radiocarbono) e foraminíferos numa secção lamosa, com intercalações de camadas arenosas.Os sedimentos da seção analisada foram depositados nos últimos 2.350 anos BP. As concentrações de Al, Cd, Co, Fe, Mn, Ni, Pb, Sn, Ti, V e Zn são mais elevadas na base do testemunho e diminuem em direção ao topo. O conteúdo de TOC, P e Zr possui padrões inversos. As razões destes elementos com o respectivo valor de fundo possuem padrões semelhantes. Porém, estudos anteriores reconheceram em várias áreas da Baía de Sepetiba um aumento das concentrações de Cd, Zn, Cr e Pb durante o século XX, principalmente devido à atividade industrial. A área onde foi coletado este testemunho poderá 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 sequência sedimentar não poluída por metais, mas bastante enriquecida em matéria orgânica foi depositada sobre a superfície da descontinuidade. Os foraminíferos eram relativamente abundantes na seção inferior (240-126 cm; entre ≈2.400-2.090 anos BP), correspondente á deposição de sedimentos antes da dragagem. Após a dragagem, a acumulação de sedimentos muito finos e ricos em matéria orgânica, gerou fenómenos de eutrofização, que terão causado uma redução drástica da abundância e diversidade destes organismos. Este trabalho testemunha o efeito da eutrofização em organismos meiofaunais. Apesar de algumas espécies de foraminíferos costeiros tolerarem efeitos nefastos causados pela eutrofização, reconhece-se que o impacto foi tão negativo que mesmo estas espécies ocorrem com abundância reduzida na área estudada. Palavras-chave: Área Costeira. Registro Paleoambiental. Impacto Antrópico. Meiofauna, Abordagem Multiproxy.

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20 years of research on the Guiana dolphin population of Sepetiba Bay, southeastern Brazil: What has changed?

Maciel,

Maricato,

Marqui

et al. 2023

Aquatic Conservation

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Despite the importance of coastal habitats for the provision of many ecosystem services, these areas are currently among the most impacted by human activities. Impacts on coastal ecosystems may affect many key species, such as the Guiana dolphin, which inhabits Sepetiba Bay in south‐eastern Brazil, a highly degraded environment owing to a human‐induced rapid environmental change. In this context, this study investigates the potential changes in the local Guiana dolphin behaviour, group structure, bioacoustics, site fidelity and habitat use over the past 20 years. For this, a historical database (1998–2007) was compared with current data on the local dolphin population (2017–2019). Between 2017 and 2019, the Guiana dolphins form significantly smaller groups (W = 3262.5, P > 0.001), spend more time foraging (61 vs. 10% in the past), emit whistles at a considerably lower rate (decreasing by 85.2%), have reduced site fidelity and now use a larger area. As Sepetiba Bay has been severely impacted by human activities in the recent past, with profound consequences for much of its biodiversity, the observed changes in dolphin behaviour are probably a consequence of habitat degradation and, in particular, of reduced prey availability. These findings have important implications for the management and conservation of the Guiana dolphin population of Sepetiba Bay. To break this human‐induced rapid environmental change, it will be essential to minimize the spatio‐temporal overlap of anthropogenic impacts, to avoid cumulative impacts. To mitigate anthropogenic impacts on the Guiana dolphins of Sepetiba Bay, it will be important to direct the following actions: (i) the regulation and control of anthropogenic noise; (ii) reduction and control of the release of chemical contaminants and organic effluents; (iii) more effective controls on vessel traffic within the areas used preferentially by the Guiana dolphin; and (iv) the implementation of measures to avoid overfishing and bycatch.

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Assessing man-induced environmental changes in the Sepetiba Bay (Southeastern Brazil) with geochemical and satellite data

Cited by 38 publications

References 35 publications

Background Concentrations of Chemical Elements in Sepetiba Bay (Se Brazil)

Background Concentrations of Chemical Elements in Sepetiba Bay (Se Brazil)

Impact of Eutrophication on Benthic Foraminifera in Sepetiba Bay (Rio De Janeiro State, Se Brazil)

20 years of research on the Guiana dolphin population of Sepetiba Bay, southeastern Brazil: What has changed?

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