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Registros recuperados: 68
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Preparing the New Phase of Argo: Technological Developments on Profiling Floats in the NAOS Project ArchiMer
André, Xavier; Le Traon, Pierre-yves; Le Reste, Serge; Dutreuil, Vincent; Leymarie, Edouard; Malardé, Damien; Marec, Claudie; Sagot, Jérôme; Amice, Martin; Babin, Marcel; Claustre, Hervé; David, Arnaud; D’ortenzio, Fabrizio; Kolodziejczyk, Nicolas; Lagunas, José Luis; Le Menn, Marc; Moreau, Bertrand; Nogré, David; Penkerc’h, Christophe; Poteau, Antoine; Renaut, Corentin; Schaeffer, Christophe; Taillandier, Vincent; Thierry, Virginie.
The international array of profiling floats known as Argo is a major component of the global ocean- and climate-observing system. In 2010, the NAOS (Novel Argo Observing System) project was selected as part of France’s Equipex “Investissement d’Avenir” program. The objectives of NAOS were to consolidate the French contribution to the Argo core mission (global temperature and salinity measurements down to 2,000 m) as well as to develop the future generation of French Argo profiling floats and prepare the next phase of the Argo program with an extension to the deep ocean (Deep-Argo), biogeochemistry (BGC-Argo) and polar seas. This paper summarizes the main technological advances and at-sea validations carried out as part of NAOS: development of a deep (4,000...
Tipo: Text Palavras-chave: Ocean; Argo; Global observing system; Profiling float; Deep; Biogeochemistry; Under-ice; Float technology.
Ano: 2020 URL: https://archimer.ifremer.fr/doc/00658/77029/78314.pdf
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Reduction du nitrate dans les sediments marins. Comparaison des activites mesurees in vitro et in situ ArchiMer
Esteves, J; Bonin, P; Blanc, F; Mille, G; Bertrand, J.
In vitro nitrate reduction in hydrocarbon-polluted marine sediments has been studied by flow-through system. By analysing the rate of nitrate comsumption as a function of nitrate concentration the authors determined the Michaelis-Menten kinetics parameters. (km = 330 mu M; vax = 2.0 mu M/g super(-1)/h super(-1). The authors found a value of 60 mu M/m super(-2)/h super(-1) for the rate of in vitro nitrate consumption derived from the above kinetic parameters and from the nitrate concentration in the sediment. In parallel a value of 67.4 mu M/m super(-2)/h super(-1) was found for the rate of nitrate consumption under in situ conditions. The great similarity between both results would favor the in vitro technique as a valid and more convenient one.
Tipo: Text Palavras-chave: MED; Biogeochemistry; Oil pollution; Methodology; Environmental conditions; Experimental research; Comparative studies; Metabolism; Bacteria; Sediment chemistry; Reduction; Nitrates; Denitrification; Nitrogen cycle.
Ano: 1984 URL: http://archimer.ifremer.fr/doc/1984/acte-979.pdf
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L'arsenic en milieu marin. Biogeochimie et ecotoxicologie ArchiMer
Michel, Pierre.
Arsenic levels of in the marine environment are high in comparison with other contaminants. Over the past twenty years, a large number of arsenic organic compounds have been identified in the water, sediments and living species. This document constitutes a synthesis of current knowledge on arsenic sources, and contamination levels, on its biogeochemical cycle as well as its toxic effects on human and marine fauna. This paper highlights in particular the effects of phosynthesis on arsenic speciation and its distribution throughout the marine environment. Problems of toxicity in the case of certain phyto- and zooplankton species are identified. Bioaccumulation in seaweeds, molluscs and fishes is documented as well, with special attention to the species...
Tipo: Text Palavras-chave: Ecotoxicology; Contamination; Biogeochemistry; Arsenic; Ecotoxicologie; Contamination; Biogéochimie; Arsenic.
Ano: 1993 URL: http://archimer.ifremer.fr/doc/1993/rapport-1448.pdf
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L’algue rouge "Gracilaria verrucosa" (hudson) papenfuss de la lagune de Bizerte (Tunisie septentrionale) : essai de culture en mode suspendu et composition biochimique OceanDocs
Mensi, F.; Ksouri, J.; Hammami, W.; Romdhane, M.S..
L'algue rouge, Gracilaria verrucosa, a été cultivée, durant le printemps 2009, en mode suspendu à différents emplacements et profondeurs représentant les différences biogéochimiques de la lagune de Bizerte au Nord de la Tunisie. La concentration et la distribution des nutriments (ammonium, phosphate) dans l'eau, ainsi que la salinité, la température, l’oxygène et la transparence de l’eau ont été déterminées. Les méthodes analytiques internationales standardisées ont été appliquées. Les effets du mode de culture, de l’emplacement et de la profondeur sur les rendements en poids, protéines, R-Phycoérythrine et sucres totaux de l’algue ont été étudiés. La croissance de Gracilaria a été similaire dans les différents sites mais plus lente dans les profondeurs...
Tipo: Journal Contribution Palavras-chave: Algal culture; Ammonium compounds; Biochemical composition; Biogeochemistry; Carbohydrates; Dissolved oxygen; Environmental conditions; Growth; Intensive culture; Lagoons; Off-bottom culture; Raw materials; Red algae; Biogeochemical cycle.
Ano: 2009 URL: http://hdl.handle.net/1834/4497
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Caractérisation géochimique des sédiments de surface du golfe de Tunis OceanDocs
Fernex, F.; Ben Mammou, A.; Added, A.; Abdeljaoued, S.; Essonni, N..
The general current of the Gulf of Tunis are dependent of the general Mediterranean current. This last divides to the level of the Gulf of Tunis in two branches; a first connects by pass west coasts of the gulf while the second branch crosses the centre of the gulf with a NNW - SSE direction. The passage of this second branch of the general current creates a central zone characterised by a sediment relatively sandier than what surrounds it and controls the distribution of the different metallic elements that have for main origin the Oued Mejerda. The metallic elements here analyzed are the Fe, Zn, Ni, Co, Cu and Pb. Their concentrations vary respectively between 0,5. and 1,6%; 279 and 447 ppm; 39 and 67 ppm; 20 and 34 ppm; 9 and 20 and between 56 and 142...
Tipo: Journal Contribution Palavras-chave: Sediments; Biogeochemistry.
Ano: 2003 URL: http://hdl.handle.net/1834/1116
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Metallophytes in Latin America: a remarkable biological and genetic resource scarcely known and studied in the region RChHN
GINOCCHIO,ROSANNA; BAKER,ALAN J.M..
In Latin America, metallic ores are abundant and diverse. However, few metal-tolerant and metal hyperaccumulator plants have been reported in the region in comparison with other areas of the world. This may be largely explained by the scarcity of scientific studies of the native vegetation growing on natural mineralized or metal-contaminated areas and the unfrequent use of biogeochemical prospecting techniques by the local mining industry, rather than the proven absence of these plants. Latin America is, however, an area where metal-tolerant and hyperaccumulator plants (metallophytes) should be found, not only because of the wealth of ore deposits and associated metal polluted areas, but also due to its high and unique plant diversity. If plant formations...
Tipo: Journal article Palavras-chave: Hyperaccumulators; Metal-tolerant plants; Biodiversity; Metal ores; Biogeochemistry.
Ano: 2004 URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0716-078X2004000100014
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Observations of cryoconite hole system processes on an Antarctic glacier RChHN
MACDONELL,SHELLEY A; FITZSIMONS,SEAN J.
Cryoconite holes are water-filled depressions that form on glacier surfaces when uneven distributions of sediment cause differential melting to occur. Cryoconite holes are important features of cold glacier systems, as they enhance meltwater generation, enable the development of complex drainage networks and facilitate the growth of microbial communities on the glacier surface. This paper describes the development of a cryoconite hole hydrological network on an Antarctic glacier, and explores the implications for nutrient storage and delivery within the glacier system. Field measurements included measuring the internal dimensions and repeat mapping of cryoconite holes across the glacier surface, and laboratory analysis included cation and anion analysis on...
Tipo: Journal article Palavras-chave: Biogeochemistry; Drainage system; Glacier hydrology; Meltwater; Solute.
Ano: 2012 URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0716-078X2012000400003
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Influence of effluents from a Wastewater Treatment Plant on nutrient distribution in a coastal creek from southern Brazil BABT
Santos,Isaac Rodrigues; Costa,Ronaldo Cataldo; Freitas,Ubiratan; Fillmann,Gilberto.
The hypothesis that effluents treated through activated sludge process cause changes in nutrient biogeochemistry of receiving water bodies was investigated in Vieira creek, southern Brazil. Dissolved oxygen, suspended matter, and pH did not vary among the sampling stations. Nutrient, biochemical oxygen demand, and conductivity values were significantly higher downstream from the Wastewater Treatment Plant (WWTP) effluents. Further downstream, nitrate concentrations were higher due to ammonium nitrification, organic matter remineralization and/or the occurrence of unidentified sources. Per capita nutrient emission factors were estimated to be 0.16 kg P.yr-1 and 4.14 kg N.yr-1. Under pristine conditions, low N:P ratios were observed, which were significantly...
Tipo: Info:eu-repo/semantics/article Palavras-chave: Activated sludge; Nutrients; Contamination; Coastal zone; Biogeochemistry; Eutrophication.
Ano: 2008 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-89132008000100019
Registros recuperados: 68
Primeira ... 1234 ... Última
 

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