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Registros recuperados: 35
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The need for aquatic pollution studies in Kenyan inland waters OceanDocs
Onyari, J.M..
The need for baseline data on pollution studies to the aquatic biota of Kenyan Inland waters is of profound importance. Aware of the possible contamination of the rivers and Lakes with heavy metals, pesticides and other pollutants used around them for the control of tropical diseases and treatment of agricultural crops, a monitoring programme is necessary.
Tipo: Journal Contribution Palavras-chave: Freshwater pollution; Pollution control; Pollution effects; Pollution control; Http://aims.fao.org/aos/agrovoc/c_6078.
Ano: 1986 URL: http://hdl.handle.net/1834/1257
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Distribution quantitative de la meiofaune dans un milieu fortement anthropise : le vieux port de Bizerte (Tunisie) OceanDocs
Essid, N.; Mahmoudi, E.; Beyrem, H.; Aissa, P.; Hedfi, A..
The survey of sediment and hydrological parameters in the old harbor of Bizerte has revealed that this ecosystem knows a high anthropogenic pressure. In this area waters were characterized by weak contents in dissolved oxygen and sediments, rich in fine fraction, were loaded in hydrocarbons and in organic matter. The free-living nematodes, predominant taxa, responded to these disturbances by a significant decrease in their densities and their biomasses and had tendency, notably at the most isolated sites, to penetrate deeply to escape surface sediments highly loaded in hydrocarbons and in organic matter.
Tipo: Journal Contribution Palavras-chave: Hydrocarbons; Pollution effects; Pollution indicators; Meiobenthos; Harbours; Man-induced effects; Bioindicators; Hydrocarbons; Http://aims.fao.org/aos/agrovoc/c_3719.
Ano: 2003 URL: http://hdl.handle.net/1834/1115
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La comunidad bentónica intermareal de Brachidontes rodriguezii (D'Orb.) y su relación con el efluente cloacal de la ciudad de Mar del Plata (38° S) OceanDocs
Vallarino, E.A..
El mitílido Brachidontes rodriguezii es el organismo estructurante de una compleja comunidad intermareal que se desarrolla sobre los sustratos intermareales duros (cuarcíticos y limo- loessoides), en el sudeste de la provincia de Buenos Aires (Argentina). El presente estudio se desarrolló durante los años 1997, 1998, 1999 y 2000, en áreas costeras de los alrededores de Mar del Plata (Camet); Santa Clara del Mar (Santa Elena) y en Mar de Cobo. Se determinaron cuatro estaciones de muestreo en la zona de Camet (área impactada) y dos áreas control en Santa Elena y Mar de Cobo. En cada muestreo se tomaron muestras biológicas, de sedimento retenido y de Materia orgánica, así como de las variables ambientales: temperatura, salinidad, oxígeno disuelto, turbidez y...
Tipo: Theses and Dissertations Palavras-chave: Intertidal environment; Biological sampling; Environmental factors; Pollution effects; Spatial variations; Seasonal variations; Biomass; Intertidal environment; Environmental factors; Biomass.
Ano: 2002 URL: http://hdl.handle.net/1834/2955
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Impact d'un lubrifiant minéral sur la structure trophique des peupelements de nématodes libres marins de la lagune de Ghar El Melh : Etude microcosmique OceanDocs
Aissa, P.; Soltani, A.; Mahmoudi, E.; Louati, H.; Beyrem, H..
Une étude microcosmique a été effectuée pour examiner l’influence d’un lubrifiant minéral avant et après son utilisation dans un moteur de véhicule sur la structure trophique de la communauté de nématodes libres originaire de la lagune de Ghar El Melh. Une concentration de 1mg kg-1 de sédiment a été testée pour évaluer l’effet du polluant après 40 jours d’exposition. Les résultats de l’étude ont révélé que les consommateurs non sélectifs (1B), les plus abondants dans le microcosme témoin, ont été très affectés et leur dominance a diminué significativement sous l’effet de la contamination par le lubrifiant minéral avant ou après usage. Les détritivores sélectifs (1A) dont la dominance augmente significativement au iveau des microcosmes traités avec le...
Tipo: Journal Contribution Palavras-chave: Microcosms; Oil pollution; Petroleum; Pollution effects; Sediments; Trophic structure.
Ano: 2008 URL: http://hdl.handle.net/1834/4255
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Diversidad de peces demersales en la plataforma continental del Ecuador OceanDocs
Moncayo, D.; Trejos, R.; Maridueña, A.; Castro, R..
Se determine el contenido de Mercurio (Hg), Cadmio (Cd) y Plomo (Pb) en 18363 muestras de productos pesqueros colectadas durante el período enero del 2006 hasta julio del 2009. La determinación fue realizada empleando espectrofotometría de Absorción Atómica por generación de vapor frío (Hg) y horno de grafito (Cd y Pb), todas las concentraciones son expresadas en peso húmedo. Los análisis fueron realizados con el propósito de verificar que los productos pesqueros a ser exportados cumplen con los niveles establecidos en el Reglamento consolidado (CE)N°1881/2006, de la Unión Europea, que fija el conte¬nido máximo de determinados contaminantes en los productos alimenticios. Las concentraciones encontradas, en las muestras de peces, en su mayoría fueron...
Tipo: Journal Contribution Palavras-chave: Heavy metals; Atomic absorption spectroscopy; Bioaccumulation; Pollution effects; Fishery products.
Ano: 2010 URL: http://hdl.handle.net/1834/4802
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The status of persistent organic pollutants in Lake Victoria catchment OceanDocs
Madadi, O.V; Wandiga, S. O; Jumba, I. O..
The use of most organochlorine pesticides has been banned or restricted in the republic of Kenya under the Rotterdam and Stockholm convention due to high levels of persistence in the environment and toxicity to nontarget organisms. Studies conducted in some parts of the country have revealed that residue levels of these compounds are still in the environment. However, the residues of these compounds have not been exhaustively studied in the Lake Victoria catchment area. This study was set to investigate the residues levels of p,p-DDT, o,p’- DDE, p,p-DDD, g-HCH, D-HCH, a-HCH, Aldrin, and Dieldrin, in water samples from Lake Victoria catchment. Samples were collected during the short rain, dry and wet seasons and analysed using gas chromatography equipped...
Tipo: Proceedings Paper Palavras-chave: Pollutants; Catchment area; Pesticides; Chemical pollutants; Toxicity; Freshwater lakes; Pollution effects; Environmental impact; Inland water environment; Pollutant persistence.
Ano: 2006 URL: http://hdl.handle.net/1834/1475
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Notas acerca de la fertilización por hierro OceanDocs
Rentería, W.; Ortega, J..
La fertilización de los océanos con hierro han sido presentada como solución a corto plazo para poder reducir CO2 de la atmósfera. Esta afirmación presentada hace 20 años ha liderado y ha despertado un controversial debate sobre las posibles consecuencias en el clima. La bioquímica del hierro es un sistema complejo y su estudio en el océano es relativamente nuevo en comparación con los otros nutrientes, sin embargo, este sistema ha sido descrito en varios estudios que ayudan en la compresión de la afirmación intrincada sobre los beneficios de la fertilización con hierro. El objetivo de este estudio es describir los aspectos relacionados con los fundamentos de la fertilización con hierro, discutiendo acerca de la afirmación de la limitación de hierro y la...
Tipo: Journal Contribution Palavras-chave: Iron; Pollution effects; Carbon dioxide.
Ano: 2012 URL: http://hdl.handle.net/1834/4715
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Effects of physical mixing on the environment of satellite lakes and dams of lake Victoria, Kenya OceanDocs
Guya, F.; Wakwabi, E.; Jembe, T.; Osumo, W.; Sitoki, L.; Ogutu, Z..
In the Lake Victoria (Kenya) catchment are found several small lakes and dams. The satellite lakes and dams are important aquifers and buffer zones for the lake. Besides the water bodies are important water sources both for livestock and domestic use. A study conducted in the water bodies between January 2003 and December 2004 showed that effects of eutrophication are wide spread in the lakes and dams. An investigation of primary productivity and effects of physical mixing and material transport was done. In Lake Sare, Lake Victoria waters are transported to the satellite lake during both day and night through Goye causeway that connects the two. The water bodies have higher rates of primary productivity than Lake Victoria. Spatial extent of oxygen...
Tipo: Proceedings Paper Palavras-chave: Dams; Eutrophication; Water reservoirs; Inland waters; Water bodies; Eutrophication; Primary production; Lake basins; Water mixing; Artificial lakes; Oxygen depletion; Endemic species; Pollution effects; Eutrophication; Dams; Http://aims.fao.org/aos/agrovoc/c_2734; Http://aims.fao.org/aos/agrovoc/c_2121.
Ano: 2006 URL: http://hdl.handle.net/1834/1494
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Investigation on possible chemical pollution of the BouGhraa lagoon south of Tunisia by chemical wastes OceanDocs
Farhat, F.; Ben Aoun, Z.; Chouba, L.; Hadj Ali, M. S..
La mer de BouGhrara, un milieu quasi-lagunaire de cinquante milles hectares environ, a contribué d’une manière remarquable à la production halieutique Tunisienne jusqu’au 1992 4.786 tonnes, année à partir de laquelle cette production n’a cessé de décroître (1.118 tonnes en 2002). Par ailleurs le premier projet industriel d’aquaculture marine y a également vu le jour, atteignant une production aquacole en cages flottantes de 252 tonnes en 1990. Malheureusement cette activité a cessé en 1995, après une dizaine d’années et la société qui assurait cette production a cessé ses activités et les quelques cages ont été déplacées de la lagune vers le bassin du port de Zarzis à la recherche de conditions environnementales meilleures. Plusieurs raisons ont été...
Tipo: Journal Contribution Palavras-chave: Chemical pollution; Depletion; Eutrophication; Lagoon fisheries; Organic matter; Pollution effects; Salinity; Temperature; Waste disposal; Acidity.
Ano: 2007 URL: http://hdl.handle.net/1834/4249
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Impact d’un lubrifiant minéral sur la structure trophique des peuplements de nématodes libres marins de la lagune de Ghar el Melh: Etude microcosmique OceanDocs
Louati, H.; Soltani, A.; Beyrem, H.; Aissa, P.; Mahmoudi, E..
Une étude microcosmique a été effectuée pour examiner l’influence d’un lubrifiant minéral avant et après son utilisation dans un moteur de véhicule sur la structure trophique de la communauté de nématodes libres originaire de la lagune de Ghar El Melh. Une concentration de 1mg kg-1 de sédiment a été testée pour évaluer l’effet du polluant après 40 jours d’exposition. Les résultats de l’étude ont révélé que les consommateurs non sélectifs (1B), les plus abondants dans le microcosme témoin, ont été très affectés et leur dominance a diminué significativement sous l’effet de la contamination par le lubrifiant minéral avant ou après usage. Les détritivores sélectifs (1A) dont la dominance augmente significativement au iveau des microcosmes traités avec le...
Tipo: Journal Contribution Palavras-chave: Microcosms; Oil pollution; Petroleum; Pollution effects; Sediments; Trophic structure; Petroleum; Http://aims.fao.org/aos/agrovoc/c_5747.
Ano: 2008 URL: http://hdl.handle.net/1834/3754
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Water quality trends and input loads to Lake Nakuru OceanDocs
Kulecho, Andrew; Muhandiki, Victor.
Water quality trends of Lake Nakuru, Kenya and its feeder streams were monitored in 2001-2004. Water samples were obtained from eleven stations in the lake and five points on inflowing streams. The items monitored were physico-chemical and biological components. The drainage basin was characterized by recurrence of dry spells throughout the period with water losses in the lake exceeding the amount received to cause a fall in water volume. The lake water salts content rose – conductivity and alkalinity reached 58 ms/cm and 5,200 mg/l respectively. PH was more or less constant (10.00 – 10.36). Daytime oxygen concentration in the mid-lake system rose (to greater than 20 mg/l) while remaining low in the inflow portions of the lake. On one occasion, the lake...
Tipo: Proceedings Paper Palavras-chave: Water quality; Biomass; Mortality causes; Anthropogenic factors; Phytoplankton; Pollution effects; Degradation; Man-induced effects; Inland waters; Freshwater pollution; Physicochemical properties; Inflow; Environmental monitoring; Land use; Urbanization; Environmental impact; Pollution; Freshwater.
Ano: 2006 URL: http://hdl.handle.net/1834/5312
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Structure trophique des peuplements de nématodes libres marins dans un milieu expérimentalement enrichi en cadmium et/ou en hydrocarbures (diesel) OceanDocs
Mahmoudi, E.; Essid, N.; Beyrem, H.; Hedfi, A.; Boufahja, F.; Aissa, P.; Vitiello, P..
Une étude en microcosme a été entreprise pour examiner l’influence d’un métal lourd (le cadmium) et/ou du diesel sur la structure trophique d’une communauté de nématodes libres provenant de la lagune de Ghar El Melh (Tunisie). Trois doses en cadmium [faible : 0,54 mg Cd kg-1 (poids sec, ps), moyenne : 0,90 mg Cd kg-1 (ps) et forte : 1,40 mg Cd kg-1(ps)], une dose de diesel de 0,25 mg kg-1 (ps) et un mélange de cadmium et de diesel [1,40 mg Cd kg-1(ps) + 0,25 mg kg-1 de diesel (ps)] ont été testées pour évaluer les effets de ces polluants après 90 jours d’exposition. Les résultats des analyses statistiques univariées n’ont montré aucune différence significative pour la plupart des indices des communautés traitées par rapport à l’assemblage témoin. Ainsi,...
Tipo: Journal Contribution Palavras-chave: Nematoda; Cadmium; Chemical pollution; Heavy metals; Microcosms; Pollution effects; Trophic structure; Heavy metals; Cadmium; Http://aims.fao.org/aos/agrovoc/c_2223; Http://aims.fao.org/aos/agrovoc/c_1178.
Ano: 2005 URL: http://hdl.handle.net/1834/3740
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Etude quantitative et qualitative des métallothioneines chez la daurade "Sparus aurata" exposée aux métaux lourds OceanDocs
Ameur, S.; Ghedira, J.; Guerbej, H.; Jebali, J.; Bouraoui, J.; Boussetta, H..
Dans l’environnement marin, les éléments traces peuvent s’accumuler dans les organismes à des concentrations supérieures à celles présentes dans l’eau. L’étude de la distribution tissulaire des métaux traces au niveau des organismes qui y sont exposés, constitue un aspect très important pour la compréhension de leur devenir. En outre, le suivi de la réponse biologique spécifique de ces organismes sentinelles aux xénobiotiques complète et consolide l’analyse chimique. Ce travail vise à étudier la distribution tissulaire des métaux traces et des métallothionéines (MTs) chez la daurade «Sparus aurata » traitée par un métal essentiel (le cuivre) et un métal non essentiel (le cadmium) à une concentration de 500µg /Kg de poids frais pendant 48 heures....
Tipo: Journal Contribution Palavras-chave: Animal organs; Bioaccumulation; Cadmium; Gills; Heavy metals; Metals; Pollutants; Pollution effects; Sediment pollution; Toxicity tests; Trace metals; Marine sciences; Biomarkers of exposure (organisms); Metallic elements.
Ano: 2009 URL: http://hdl.handle.net/1834/4448
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A case study of ships forming and not forming tracks in moderately polluted clouds OMA
Noone, K.J.; Öström, E.; Ferek, R.J.; Garrett, T.; Hobbs, P.V.; Johnson, D.W.; Taylor, J.P.; Russell, L.M.; Flagan, R.C.; Seinfeld, J.H.; O'Dowd, C.D.; Smith, M.H.; Durkee, P.A.; Nielsen, K.; Hudson, J.G.; Pockalny, R.A.; De Bock, L.; Van Grieken, R.E.; Gasparovic, R.F.; Brooks, I..
The effects of anthropogenic particulate emissions from ships on the radiative, microphysical, and chemical properties of m(oderately polluted marine stratiform clouds are examined. A case study of two ships in the same air mass is presented where one of the vessels caused a discernible ship track while the other did not. <i>In situ</i> measurements of cloud droplet size distributions, liquid water content, and cloud radiative properties, as well as aerosol size distributions (outside cloud, interstitial, and cloud droplet residual particles) and aerosol chemistry, are presented. These are related to measurements of cloud radiative properties. The differences between the aerosol in the two ship plumes are discussed; these indicate that...
Tipo: Info:eu-repo/semantics/article Palavras-chave: Aerosols; Air pollution; Albedo; Anthropogenic factors; Atmospheric boundary layer; Atmospheric particulates; Chemical plumes; Cloud physics; Clouds; Droplets; Fuels; Ocean-atmosphere system; Pollution effects; Radiative transfer; Ships; Size distribution.
Ano: 2000 URL: http://www.vliz.be/nl/open-marien-archief?module=ref&refid=8840
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Single particle analysis of aerosols, observed in the marine boundary layer during the Monterey Area Ship Tracks Experiment (MAST), with respect to cloud droplet formation OMA
De Bock, L.A.; Joos, P.E.; Noone, K.J.; Pockalny, R.A.; Van Grieken, R.E..
The chemical composition of individual particles >0.2 µm sampled during the MAST-experiment were analysed by SEM-EDX, in combination with multivariate techniques. The objective of this experiment was to identify the mechanisms responsible for the modification of marine stratocumulus clouds by emissions from ships and in a wider sense to provide information on the global processes involved in atmospheric modification of cloud albedo. Aerosols were examined under different MBL pollution levels (clean, intermediately polluted and moderately polluted) in five different reservoirs: background below-cloud and above-cloud aerosol; background cloud droplet residual particles; below-cloud ship plume aerosol and ship track cloud droplet residual particles. In...
Tipo: Info:eu-repo/semantics/article Palavras-chave: Aerosols; Albedo; Atmospheric boundary layer; Atmospheric particulates; Chemical composition; Clouds; Droplets; Pollution effects; INE.
Ano: 2000 URL: http://www.vliz.be/nl/open-marien-archief?module=ref&refid=8877
Registros recuperados: 35
Primeira ... 12 ... Última
 

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