Hydrologie et morphologie de l’estuaire du fleuve Sassandra, Basse Côte d’Ivoire

Les études physico-chimiques des eaux de surface et de sub-surface et les levés bathymétriques effectués dans l’estuaire du fleuve Sassandra, ont permis de caractériser l’hydrologie et la morphologie du fond de cet embouchure. Sur toute la surface d’eau le pH est proche de la neutralité, la conductivité est comprise entre 50 et 200μs/cm, avec une température moyenne de 28,91°C. La salinité de l’estuaire augmente au fur et à mesure que l’on s’approche de l’océan Atlantique. Sa valeur est comprise entre 0 et 4%. Le taux d’oxygène, très faible à l’embouchure avec une valeur de 2 mg /L contre 8,30 mg/L dans la branche droite du fleuve couverte par la végétation. Les Matières En Suspension (MES) analysées sont constituées d’une fraction inorganique de quartz, feldspath, amphibole, mica, argiles, etc...et d’une fraction organique constituée de débris animaux et végétaux. Cette étude a permis de réaliser les cartes bathymétriques et la répartition des paramètres physico-chimiques, ainsi que la détermination des dépressions et les processus d’érosions au fond de l’estuaire du fleuve Sassandra.Mots-clés: hydrologie, bathymétrie, paramètres physico-chimiques, fleuve Sassandra, Côte d’Ivoire. Hydrology and morphology of the estuary of the Sassandrariver (Low Côte d’Ivoire) The physico-chemical studies of waters of surface and sub-surface and the bathymetric sunrises made in the estuary of theSassandrariver, allowed to characterize the hydrology and the morphology of the bottom of this mouth. On all the surface of water the pH is close to the neutrality, the conductivity is between 50 and 200μs/cm, with an average temperature of 28,91°C. The salinity of the estuary increases as we approach the Atlantic Ocean. His value is between 0 and 4%. The rate of oxygen, very low in the mouth with a value of 2 mg / L against 8,30 mg / L in the straight branch of the river covered by the vegetation. Suspension materials (MES) analyzed are constituted by an inorganic fraction of quartz, feldspar, amphibole, mica and clays etc. and of an organic fraction constituted by animal and plant fragments. This study allowed to realize the bathymetric maps and the distribution of the physico-chemical parameters, as well as the determination of the depressions and the processes of erosions at the bottom of the estuary of the Sassandra river.Keywords: hydrology, bathymetry, physico-chemical parameters, Sassandra river, Côte d’Ivoire

Influence d'un faible niveau d'ingestion sur la digestion et le comportement alimentaire chez la vache recevant un régime très digestible

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Influence of the Cassava Harvest Month on the Sensory Parameters of Attiéké

Cassava is an important staple food around the world, especially in Africa. It is cultivated throughout the Ivorian territory with predominance in the South. Due to the high demand, some producers opt for an early harvest, neglecting the impact of the harvest stage on the sensory parameters of cassava root derivatives. The objective of this work was to determine the stage of harvest allowing obtaining products of good sensory quality. The sensory characteristics of the attiéké were evaluated at different stages of harvest (11th, 12th, 13th and 14th months after planting the cuttings) of the cassava roots of the Yacé variety which were used for its production. The attiéké obtained in the twelfth month of harvest was generally much appreciated because it was less acidic, less fibrous and more homogeneous and had a better smell. Thus, cassava harvested in the twelfth month of cultivation makes it possible to obtain attiéké with the best sensory characteristics. Therefore, this stage of maturity of cassava roots is recommended for attiéké producers

Seasonal Variability of Carbon Dioxide in the Rivers and Lagoons of Ivory Coast (West Africa)

peer reviewedWe report partial pressure of CO2 (pCO2) and ancillary data in three rivers (Bia, Tanoé, and Comoé) and five lagoons (Tendo, Aby, Ebrié, Potou, and Grand-Lahou) in Ivory Coast (West Africa), during four cruises covering the main climatic seasons. The three rivers were oversaturated in CO2 with respect to atmospheric equilibrium, and the seasonal variability of pCO2 was due to dilution during the flooding period. Surface waters of the Potou, Ebrié, and Grand-Lahou lagoons were oversaturated in CO2 during all seasons. These lagoons behaved similarly to the oligohaline regions of macrotidal estuaries that are CO2 sources to the atmosphere due to net ecosystem heterotrophy and inputs of riverine CO2 rich waters. The Aby and Tendo lagoons were undersaturated in CO2 with respect to the atmosphere because of their permanent haline stratification (unlike the other lagoons) that seemed to lead to higher phytoplankton production and export of organic carbon below the pycnocline