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473.More information
Sediment samples used in this work were taken from two different sites (maturation pond of Boujaad lagunage and fry pond of the Deroua fish farm) in order to understand and compare the conditions affecting phosphate exchanges across water-sediment interface.This study showed a difference in the chemical composition of the two sediments. In the fry pond, the majority of the phosphate was present as inorganic phosphate (92.5%), especially in forms bound to calcium. On the other hand, total phosphate was divided equally into organic (49.2%) and inorganic (49.8%) phosphorus in the maturation pond. In this pond, phosphate solubility increased in the interstitial water under anoxic conditions. The phosphate released came principally from the inorganic fraction, particularly from Fe(OOH)-P. The maturation pond sediments, which had accumulated much organic matter, liberated more orthophosphate than did the fry pond sediments. Under air flushing, phosphate adsorption is significant particularly in the maturation and fry pond sediments.
Keywords: Phosphore, bassin de maturation, étang d'alevinage, relargage, fixation, Phosphate, maturation pond, fry pond, release, adsorption
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474.More information
Pythium diclinum, isolated for the first time from Moroccan waters, produces several volatile metabolites with very diverse properties including, for example, 4-hydroxybenzaldehyde which is involved in the pathogenesis of several other micro-organisms, and tridecane which is a pollutant. Other detected compounds include the odoriferous molecules such as cyclotetradecane, 2 ethylhexanol and benzaldehyde, the presence of which suggests a possible contribution of Oomycetes to odour and taste problems in drinking waters. This study also showed that Pythium species are pathogens for several crops, owing to their production of enzymes and toxins. They are also able to produce beneficial compounds, such as myristic acid and phenylethanol, which are used particularly in the cosmetic, pharmaceutical and agro-alimentary industries.
Keywords: Pythium diclinum, composés volatils, retenue du barrage, pollution, Pythium diclinum, volatile compounds, pollution, dam reservoir