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| Registros recuperados: 132 | |
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| Vilhena,Maria do Perpetuo Socorro Progene; Costa,Marcondes Lima da; Berrêdo,José Francisco; Paiva,Rosildo Santos; Almeida,Pryscila Denise. |
| Phytoplankton is important bioindicator of chemical and biological modifications of natural ecosystems. The objective of this study was to determine the total chemical composition of the phytoplankton of the Pará and Mocajuba estuaries on the eastern coast of the Amazon region in the Brazilian state of Pará. The chemical composition of the surface water, bottom sediments (total sample and bioavailable fraction), and the phytoplankton were determined by inductively coupled plasma optical emission spectrometry. Phytoplankton contained high concentrations of Ca, P, Mn, Fe, Zn, Al, Ba, and Pb. The phytoplankton of the Mocajuba estuary is rich in Fe (2,967-84,750 µg g-1), while those from the Pará is rich in Al (1,216-15,389 µgg-1), probably reflecting... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Sediments; Trace metals; Plankton; Surface water. |
| Ano: 2014 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0044-59672014000400012 |
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| Fonseca,Estefan M; Baptista Neto,José A; Fernandez,Marcos A; Mcalister,John; Smith,Bernard. |
| The accelerated urbanisation without a planning, brought several environmental problems to Rio de Janeiro coastal zone, especially in areas such as Rodrigo de Freitas lagoon, which receives a great amount of untreated sewage every day. To assess the nature, potentially sources and extent of heavy metal pollution in the lagoon, sediments from the surrounding streets, from the entrance of the main canal that drains to the lagoon and from the bottom of the lagoon were collected and analysed by a modified selective extraction procedure in order to study the geochemical partitioning and bioavailability of Zn, Cu, Cr, Ni and Pb in these three compartments. The present study verified an increase in the Cu, Pb and Zn concentrations in the north of the Rodrigo de... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Heavy metals; Rodrigo de Freitas lagoon; Sediments. |
| Ano: 2011 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0001-37652011000200008 |
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| LACERDA,LUIZ D.; SANTOS,JANAÍNA A.; MARINS,ROZANE V.; SILVA,FRANCISCO A.T.F. DA. |
| Abstract This work reviews the limnology of the largest multi-use reservoir in NE Brazil, the Castanhão Reservoir in Ceará State, during 5 years of an extended drought when the reservoir’s volume decreased from 88% to about 30%. Major physical and chemical parameters of the water column, phytoplankton community, trophic state and sediment geochemistry were monitored, as well as the impact from extensive aquaculture. Water quality of the full reservoir was maintained due to hydrodynamics, which transport nutrients to the hypolimnion of a stratified water column, rendering an oligotrophic state to the reservoir, notwithstanding the large nutrient inputs from aquaculture and irrigated agriculture. However, with the extension of the drought period, the... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Hydrochemistry; Hydrodynamics; Nutrients; Water quality; Sediments; Aquaculture. |
| Ano: 2018 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0001-37652018000502073 |
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| CORREIA,LÍVIA O.; SIQUEIRA JÚNIOR,SÉRGIO; CARNEIRO,PAULO L.S.; BEZERRA,MARCOS A.. |
| This paper presents a study on the viability of the use of tissues of the Leptodactylus ocellatus species (Anura Leptodactylidae) as a bioindicator of metal pollution. The study is based on the determination and correlation of the concentrations of manganese, chromium, zinc, nickel, copper and iron in sediments and tissues (skin, muscles and viscera) of the frog Leptodactylus ocellatus collected in the middle region of the Contas River in Bahia, Brazil. The highest levels of the metals studied were found in the viscera of this animal. In this tissue, a higher correlation of the concentration of these metals with those found in sediments was also observed. The concentrations of elements found in the skin and muscles of these amphibians have revealed no... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Leptodactylus ocellatus; Bioindicators; Sediments; Metals; Contas River. |
| Ano: 2014 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0001-37652014000401549 |
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| SANTOS,QUEILA O.; MORENO,ISLANIA; SANTOS,LEANDRO DOS; SANTOS,ALDENOR G.; SOUZA,VALDINEI S.; BEZERRA,MARCOS A.. |
| A modified simplex algorithm was used to optimize a system of preconcentration for cadmium determination in samples of sediments, cigarettes and food using flame atomic absorption spectrometry. The preconcentration system is based on the sorption of cadmium in a minicolumn packed with Amberlite XAD-2 resin functionalized with 3,4-dihydroxybenzoic acid (DHB). The optimized variables were pH and sampling flow rate and the optimum conditions found for these variables were, respectively 8.7 and 8.8 mL min-1. The developed system showed a preconcentration factor of 15.3, detection limit of 0.49 µg L-1, quantification limit of 1.65 µg L-1 and precision expressed as relative standard deviation (% RSD, n=10) of 5.9. The accuracy of the method was checked by... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Simplex optimization; Preconcentration; Cadmium; Sediments; Cigarettes; Food. |
| Ano: 2016 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0001-37652016000300791 |
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| Machado,Vanessa de Souza; Volkmer-Ribeiro,Cecilia; Iannuzzi,Roberto. |
| The Cemitério Paleolake, Catalão, Goiás, is a lacustrine deposit that is rich in spicules of continental sponges. These spicules, which are present in three sections (1-3), were analyzed for the taxonomic identification of the species in order to reconstruct the late Quaternary palaeoenvironment. An indigenous assemblage of lentic sponges was found, consisting of Metania spinata (Carter 1881), Dosilia pydanieli Volkmer-Ribeiro (1992), Radiospongilla amazonensis Volkmer-Ribeiro and Maciel (1983), Trochospongilla variabilis Bonetto and Ezcurra de Drago (1973), Corvomeyenia thumi (Traxler 1895), Heterorotula fistula Volkmer-Ribeiro and Motta (1995), plus Corvoheteromeyenia australis (Bonetto and Ezcurra de Drago 1966), which here has its first record in an... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Cerrado Biome; Continental sponges; Quaternary paleointerpretations; Sediments; Spicules. |
| Ano: 2012 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0001-37652012000100004 |
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| Yasir,Muhammad. |
| Abstract In this study for the first-time microbial communities in the caves located in the mountain range of Hindu Kush were evaluated. The samples were analyzed using culture-independent (16S rRNA gene amplicon sequencing) and culture-dependent methods. The amplicon sequencing results revealed a broad taxonomic diversity, including 21 phyla and 20 candidate phyla. Proteobacteria were dominant in both caves, followed by Bacteroidetes, Actinobacteria, Firmicutes, Verrucomicrobia, Planctomycetes, and the archaeal phylum Euryarchaeota. Representative operational taxonomic units from Koat Maqbari Ghaar and Smasse-Rawo Ghaar were grouped into 235 and 445 different genera, respectively. Comparative analysis of the cultured bacterial isolates revealed distinct... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Caves; 16S ribosomal RNA; Microbiota; Antimicrobial; Sediments. |
| Ano: 2018 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1517-83822018000200248 |
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| Galván Escobedo, Iris Grisel. |
| El Museo Nacional de las Culturas (MNC) ubicado en el centro histórico de la ciudad de México, es un edificio que fue construido en 1734 sobre los restos de la antigua ciudad de México -Tenochtitlán habitada por los mexicas (1324-1521). En el MNC se realizaron excavaciones arqueológicas con el objeto de recuperar información histórica relacionada con el sitio, tendientes a una restauración integral del edificio y su posterior adecuación museográfica. De los trabajos arqueológicos se derivó esta tesis que tuvo como finalidad recuperar los restos vegetales contenidos en los depósitos sedimentológicos de las excavaciones arqueológicas, para establecer las condiciones paleoecológicas de la región y el posible uso de plantas. Se analizaron 50 muestras de... |
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Palavras-chave: Arqueobotánica; Sedimentos; Semillas; Maderas; Polen; Archaeobotany; Sediments; Seeds; Wood; Pollen; Maestría; Botánica. |
| Ano: 2010 |
URL: http://hdl.handle.net/10521/142 |
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| Galván Escobedo, Iris Grisel. |
| El Museo Nacional de las Culturas (MNC) ubicado en el centro histórico de la ciudad de México, es un edificio que fue construido en 1734 sobre los restos de la antigua ciudad de México -Tenochtitlán habitada por los mexicas (1324-1521). En el MNC se realizaron excavaciones arqueológicas con el objeto de recuperar información histórica relacionada con el sitio, tendientes a una restauración integral del edificio y su posterior adecuación museográfica. De los trabajos arqueológicos se derivó esta tesis que tuvo como finalidad recuperar los restos vegetales contenidos en los depósitos sedimentológicos de las excavaciones arqueológicas, para establecer las condiciones paleoecológicas de la región y el posible uso de plantas. Se analizaron 50 muestras de... |
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Palavras-chave: Arqueobotánica; Sedimentos; Semillas; Maderas; Polen; Archaeobotany; Sediments; Seeds; Wood; Pollen; Maestría; Botánica. |
| Ano: 2010 |
URL: http://hdl.handle.net/10521/142 |
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| Ramírez Cruz, Maidali Erizabeth. |
| Los incendios forestales, además de afectar la calidad del aire y la cubierta vegetal, provocan cambios importantes en las propiedades hidrológicas del suelo, aceleran el proceso de erosión y contaminan por sedimentación. Sin embargo, en México, la información relacionada con los incendios esta más enfocada a estudiar y documentar el impacto ambiental sobre la calidad del aire y la cubierta vegetal, sin ahondar en los efectos sobre el suelo , el escurrimiento superficial y la producción de sedimentos. Por tal motivo, el objetivo de este trabajo fue evaluar la severidad de la quema sobre la infiltración del agua, la producción de escurrimiento superficial y sedimentos. Se evaluaron doce tratamientos derivados de las cuatro severidades de quema... |
| Tipo: Tesis |
Palavras-chave: Severidad de quema; Sedimentos; Escurrimiento superficial; Lluvia simulada; Doctorado; Hidrociencias; Fire severity; Sediments; Surface runoff; Simulated rain. |
| Ano: 2009 |
URL: http://hdl.handle.net/10521/1292 |
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| Abdou, M.; Schaefer, J.; Cobelo-garcia, A.; Neira, P.; Petit, J. C. J.; Auger, Dominique; Chiffoleau, Jean-francois; Blanc, Gerard. |
| Platinum Group Metals (PGM) are modern, technologically relevant elements for which (i) the anthropogenic cycle has outcompeted the natural cycles and (ii) environmental behavior, fate and impact are still widely unknown. Stripping voltammetry was used for accurate determinations of platinum (Pt) in historical records of river sediments and estuarine oysters from the Gironde fluvial-estuarine continuum (SW France) comprising the Lot River. Sediment cores from the Lot River, dated from 1952 to 2001, showed past Pt contamination due to former industrial (smelter) activities in the Lot River watershed. These samples revealed the phasing-out of a historical Pt contamination with Pt/Th (Thorium) values of 11 × 10− 5 ± 0.79 × 10− 5 for the deepest part of the... |
| Tipo: Text |
Palavras-chave: Platinum; Sediments; Wild oysters; Bioaccumulation. |
| Ano: 2016 |
URL: http://archimer.ifremer.fr/doc/00311/42177/41478.pdf |
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| Idardare, Zaina; Chiffoleau, Jean-francois; Moukrim, A; Alla, A; Auger, Dominique; Lefrere, L; Rozuel, Emmanuelle. |
| Metal concentrations were measured monthly during an annual cycle (December 2004 to January 2006) in the tissues of Nereis diversicolor ragworms and sediment from two Moroccan Atlantic coastal lagoons: Oualidia in the north, situated in a highly industrialised urban area and Khnifiss in the south, far from anthropogenic influences. Relatively high levels of Zn, Ag and Cd were found in the sediment of Oualidia lagoon, while Ni concentrations were shown to be high at Khnifiss. The significant metal levels at Oualidia are a result of industrial and urban discharges, coupled with discharges from adjacent phosphate ore processing plants. Trace metal concentrations in worms vary according to season; they are usually high in winter and spring, in relation to the... |
| Tipo: Text |
Palavras-chave: Morocco; Coastal lagoons; Sediments; Nereis diversicolor; Metals. |
| Ano: 2008 |
URL: http://archimer.ifremer.fr/doc/2008/publication-6127.pdf |
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| Luoma, S. |
| It has been established that direct uptake of (at least some) trace metals from sediments contributes to metal concentrations in benthic organisms. Important controls on metal uptake from sediment are the concentration of the exposure, the partitioning of the metals among components of the sediment, and the redox potential of the sediment. Important problems in ecology, physiology, geochemistry and biogeochemistry remain unresolved, however, and a concentrated interdisciplinary research effort will be necessary before a complete understanding of the fate and impact of sediment-bound metals will be possible. |
| Tipo: Text |
Palavras-chave: Bioaccumulation; Benthos; Food webs; Biogeochemical cycle; Sediments; Availability; Trace metals. |
| Ano: 1985 |
URL: http://archimer.ifremer.fr/doc/1985/acte-1302.pdf |
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| Christensen, Jp. |
| A diagenetic model of porewater O-2 was used to examine the relationship between organic carbon flux to the sediments and benthic oxygen demand (BOD). The model predicted that the organic carbon influx to sediments balances BOD as long as sediments are oxygenated. The critical rate occurs when O-2 at infinite depth disappears. With influxes exceeding the critical rate, the O-2 flux into the sediments via molecular diffusion can not consume all incoming organic matter, and anaerobic conditions result in BOD underestimating the carbon influx. Given that low rates of deep-sea BOD approximate the carbon influx below 9 g.C.m(-2).y(-1), a significant multilinear regression was found between published BOD, primary productivity (P-p, both in g.C.m(-2).y(-1))(,)... |
| Tipo: Text |
Palavras-chave: Fonds marins; Oxygène; Production primaire; Respiration; Sédiments; Deep-sea; Oxygen; Primary productivity; Respiration; Sediments. |
| Ano: 2000 |
URL: http://archimer.ifremer.fr/doc/00325/43578/44046.pdf |
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| Mansour, Rassoul; Rioual, S.; Lescop, B.; Talbot, P.; Abboud, M.; Farah, W.; Tanné, G.. |
| In this study, a sensor based on the development of a planar antenna immersed in sediments dedicated to water content monitoring in this type of material is proposed and experimentally validated. It is produced by a conventional Printed Circuit Board (PCB) manufacturing process on a double-sided metalized FR4 substrate. The sensitivity of the sensor is ensured by the variation of the real part of the complex dielectric permittivity of sediments with water content at around 1 GHz. As shown, in this frequency range, electrode polarization and Maxwell–Wagner polarization e ects become negligible, leading to only a bulk water polarization sensitivity. The sensor operates in the reflection mode by monitoring the variation of the resonant frequency as a function... |
| Tipo: Text |
Palavras-chave: Resonant sensor; Water content; Dielectric characterization; Microwave; Antenna; Sediments. |
| Ano: 2020 |
URL: https://archimer.ifremer.fr/doc/00610/72167/70939.pdf |
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| Registros recuperados: 132 | |
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