http://hdl.handle.net/1834/1337 Thu, 23 May 2013 14:19:00 GMT 2013-05-23T14:19:00Z http://hdl.handle.net/1834/4723 Title: Note de conjoncture Editors: Ministère de la Pêche et des Affaires Maritimes,Observatoire Economique de la Pêche au Sénégal (OEBS), Dakar (Sénégal) Abstract: L’analyse des résultats de la pêche artisanale, des sites sous revus, au premier semestre 2012, révèle une hausse globale de 13% des débarquements et de 15% de la valeur commerciale estimée (VCE) par rapport à la même période de 2011. Le sous secteur de la pêche industrielle, à l’exception de la pêche sardinière qui n’a pas fait l’objet de d’analyse dans cette note par faute de données disponibles, se caractérise par une baisse des débarquements de la pêche chalutière de 33% et une production de 1403,71 tonnes de la thonière au premier semestre 2012 comparativement à la même période de 2011 qui n’avait pas enregistré de débarquements. La transformation artisanale au niveau du site de Joal est marquée par une faible baisse de 4% de la production. Cette baisse est consécutive à la diminution de la production du kethiakh et du tambadiang respectivement 4% et 42%. Les marchés centraux au poisson de Dakar et de Kaolack ont enregistré respectivement une baisse de 1% et une hausse de 2% des apports en produits halieutiques. Ceux-ci sont essentiellement marqués par la prédominance des sardinelles rondes (82% à Dakar et 65% à Kaolack) qui ont enregistrée une baisse de 19% au marché de Dakar et de 4% au marché de Kaolack par rapport à la même période de l’année dernière. Tue, 01 Jan 2013 00:00:00 GMT http://hdl.handle.net/1834/4723 2013-01-01T00:00:00Z http://hdl.handle.net/1834/4555 Title: Photooxidation of Dimethylnaphthalene in Deionized water, Red Sea Arti cal water, and Red Sea Natural water Authors: Ali, Aasim Abstract: Red Sea water samples were collected from the Sudanese coast at depths of 10 meter during June 2011 and analyzed for major and trace metals in addition to some inorganic anions. Sodium Na, potassium K, strontium Sr, magnesium Mg, calcium Ca, sulfur S, iron Fe, zinc Zn, manganese Mn, nickel Ni, copper Cu, cadmium Cd, cobalt Co, lead Pb, arsenic As, barium Ba, chromium Cr, europium Eu, lanthanum La, silicon Si, and titanium Ti were analyzed using inductively coupled plasma optical emission spectroscopy (ICP-OES) to determine their existing concentration, their distribution patterns, study the level of contamination in the Red Sea Sudanese coastal water, and the data of the analysis was used in the preparation of the Red Sea arti cial water which was used in the photooxidation of 1,8-dimethylnaphthalene to study the salt e ect on the photooxidation of 1,8-dimethylnaphthalene in Red Sea water. tion patterns and. The inorganic anions, sulfate, chloride, and bromide were determined using ion chromatography (IC). The averages concentrations in ppm (mg/L) of major metals , Na, Mg, Ca, and K are 11870.25, 1449.2, 468.967, and 388.955 respectively. The results shown a small range of variation and regional irregularities. The results also revealed a very high concentration of sodium, and high concentration of magnesium and calcium. In addition to Copper and titanium which was not detected or has concentrationbelow thedetection limit, Arsent (As), Cobalt (Co), Chromium (Cr), Lanthanium(La), and Euribium (Eu) were all not detected, or their concentrations in the Red sea coastal water are below the detection limit of the instrument, hence,preconcentration should be done.The averages concentrations of trace metals in ppm (mg/L), B, Ba, Fe, Li, Mn, Si, Sr, Zn are 4.1935, 0.005515, 0.02524, 0.25073, 0.000085, 0.0656, 7.59765, and 0.006795 respectively. These results revealed . The results shown a small concentration of Sr and this decrease in Sr may be due to the presence of Acantharians. Ba, Sr, Si and Li are not signi cantly di erent in all areas Indicating no distinct concentration gradient. The concentration of iron Fe in Sudanese Red Sea coastal water is high and this increase in concentration can be due to the suspended particles in Sudanese Red Sea because it was not ltered or due to the pollution because also the concentration of Zn in this study is high. The averages concentrations in ppm (mg/L) of chloride, sulfate, and bromide are, 23240.515,3138.26025, and 61.795 respectively. The results show a small range of variation and regional irregularities. Also, the concentration of chloride is signi cantly. The concentration of sulfate is high. Thus, the high salinity of Red Sea coastal water is due to high concentration of sodium and chloride ions only. Photochemical experiments on the photooxidation of 1,8-dimethylnaphthalene (1,8 DMN) under arti cial sunlight and natural sunlight in deionized water, Red Sea natural water, North Sea natural water, and Red Sea arti cial water, revealed that the photooxidation of 1,8-DMN does not occur in the absence of light at 8C unless the temperature of the media is 35 Cor greater. The results shown that the e ciency of the photooxidation of 1,8-DMN is low and depend on the light intensity, and photosensitizes. The soluble fraction from the Sudanese heavy crude oil was identi ed. Sun, 01 Jan 2012 00:00:00 GMT http://hdl.handle.net/1834/4555 2012-01-01T00:00:00Z http://hdl.handle.net/1834/4557 Title: Wave runup estimates at gentle beaches in the northern Indian Ocean Authors: Abdalazeez, Ahmed Abstract: The aim of this study is to estimate the wave runup on selected beaches around the northern Indian Ocean. The runup has been estimated using ERA-Interim, which is the latest global atmospheric re-analysis produced by the European Center for Medium-Range Weather Forecasts (ECMWF). ECMWF uses the global Wave Model (WAM) model to calculate two dimensional wave spectra. The distances between the model grid points and the beaches have been calculated by a great circle calculator. The beach slopes have been calculated by Google Earth for all locations, except Maldives beach, which was assumed as an imaginary beach because the method of calculating the slope could not be used there. The significant wave height as well as the peak wave period at the grid points are assumed to be the same at the beach. The most frequent estimated runup is between 0.5 m and 1.0 m, which is produced by swell coming from the southern Indian Ocean for all locations except Sri Lanka, India and Maldives shores, where the most frequent runup value is less than 0.5 m. However, the extreme wave runup occurs with the largest wave heights during summer monsoon in July. Generally, the high wave height depends on wind speed. The mean elevation of the runup for all locations is 0.56 m. It is comparable to the measured values obtained by (Stochdon et al., 2006) at several beaches in USA and the Netherlands who found the mean value of dissipative sites (84 cm) for all experiments. Sun, 01 Jan 2012 00:00:00 GMT http://hdl.handle.net/1834/4557 2012-01-01T00:00:00Z http://hdl.handle.net/1834/4558 Title: Study of Inter-annual Variability of Chlorophyll in the Red Sea Authors: Elawad,Abubakr Abstract: This thesis studies and estimates interannual chlorophyll-a concentration in the Red Sea water using SeaWIFS, MERIS and MOIDS data. We use the data of Chlorophyll-a (CHL-a) for the period from 1998 to 2009 as well as other physical parameters such as, sea surface temperature (SST), photosynthetic available radiation (PAR), wind and mixed layer depth (MLD) to study what control the inter-annual variations of phytoplankton blooms in the Red Sea. The area under study is divided into three zones which cover the north, the middle and the south zones of the Red Sea. When considering the data seasonally, the CHL-a shows that blooms alwaysoccur in the Red Sea during winter. For each zone, the start and the end of the blooms are different from other zones. During all three zones, the CHL-a is increasing during winter and decreasing during the summer for example, the average high value of CHL-a in the north zone during the blooms is (0.26 mg/m3 ) and the minimum value is (0.14 mg/m3 ). only in the south the blooms started in the summer in September and the highest value of CHL-a during the blooms recored is the south too (0.9 mg/m3 ). The study shows that the physical parameters have effect in the blooms sizes In each zone, significant correlations between CHL-a and some of the physical parameters is found indicating how physical processes may control the phytoplankton blooms in the study area. such as the wind in the south showed up the controloing of CHL-a by the positive correlation that CHL-a and wind had during the blooms (0.740). Interannual variations are computed as monthly anomalies relative to the 1998-2009 monthly climatology. In this way, the effect of co-variation between different variables on the seasonal time scale is minimized, The anomaly data showed clear inter-annual variations in almost all parameter and zones. Strong co-variations between CHL-a and the physical parameters showed that physical process have effect on the interannual changes in the phytoplankton blooms in the Red Sea. Few highly anomalous years in some of the parameters produce a weak long-term (1998-2009) trends. Such as, in the southern zone of the Red Sea when the value of R2 =0.0157 according the high value of CHL-a in 2008 and 2009 approximately 0.28 mg/m3 for both of them. The value of R2 becomes 0.0009 when these two years have been removed. Sun, 01 Jan 2012 00:00:00 GMT http://hdl.handle.net/1834/4558 2012-01-01T00:00:00Z