L'adaptation au changement climatique dans le bassin de Tensift au Maroc par une gestion améliorée du bassin versant et le paiement pour les services environnementaux - rapport final

Ce projet bénéficie d'une subvention du Centre de recherches pour le développement international (CRDI), Ottawa, Canada.Le défi que le présent projet de recherche a essayé de relever est de trouver des pistes pour repenser la GIRE dans un contexte du changement climatique, tout en prenant en considération le maintien de la production des biens et services environnementaux. Ceci ne pourra se réaliser qu’à travers des actions permettant de prendre en considération la donne climatique et les instruments basés sur le marché (e.g. le Paiement pour les Services Environnementaux (PSE)) dans les politiques de gestion de l’eau

Metal fluxes to the sediments of the Moulay Bousselham lagoon, Morocco.

International audienceThe metal content in surface sediments (0-2 cm, 26 samples), in a sediment core (120, 1 cm slices), taken from Moulay Bousselham (Morocco) was investigated. Concentrations of Al, Fe, Mn, Pb, Zn, Cu, Ni, Cr, Cd, As, and Hg were evaluated in surface and cored sediments of Moulay Bousselham lagoon. Significantly high concentrations in lg g-1 dw of Pb (31.7-6.2), Zn (758.9-167), Cu (310.7- 22), Ni (96-10.5), Cr (113-18.9), Cd (0.84-0.02), As (1-0.1), and Hg (0.61-0.02) were found in sediment samples from Moulay Bousselham lagoon. Calculated enrichment factors [EFMe = (Me/Al)sample/(Me/Al)background], using Al as a normalizer, and correlation matrices showed that metal pollution in Merja Zerga of Moulay Bousselham lagoon was the product of anthropogenic sources, while the metal content in Merja Kehla was of natural origins. The results suggest that a major change in the sedimentary regime of the lagoon, associated with internal trapping and re-distribution of heavy metal, has been occurring in the past few decades. The cause would appear to be the construction of a Nador Canal at the lagoon. Probable effects concentrations (PEC) were often exceeded for heavy metals in the lagoon sediments, especially for Zn, Cu, Ni, and Cr, and four stations, stations MZ-11, MZ-12, MZ-13, MZ-14, MZ-16, and MZ-17, had multiple metals at presumptively toxic levels. These comparisons suggest that sediment metal levels in the river are clearly high and probably pose an environmental risk at some stations. The levels of most of the metals were not greatly enriched, a consideration that is of the utmost importance when contamination issues are at stake. Metal concentrations found in Moulay Bousselham lagoon were comparable to aquatic systems classified as contaminated from other regions of the world

Growth performance and biochemical composition of nineteen microalgae collected from different Moroccan reservoirs

International audienceMacro- and microalgae have recently received much attention due to their valuable chemical constituents. In order to increase existing data, the authors studied nineteen microalgae species isolated from different reservoirs in the Fez region (northern Morocco), undertaking experiments to determine for each species the specific growth rate, their total amounts of proteins, carbohydrates and lipids and the influence of the growth phase on these chemical constituents. The growth rates of the nineteen studied species of microalgae showed a wide interspecies variation, ranging from 0.27 d-1 for Chlamydomonas nivalis to 3.64 d-1 for Chlorococcum wemmeri. Protein, carbohydrate and lipid contents also varied greatly between taxa and within genera. Ankistrodesmus falcatus, Chlamydomonas nivalis, Chlorococcum sp., Fragilaria ulna, Scenedesmus protuberans, and Synechocystis aquatilis tended to synthesize proteins, the concentrations exceeding 20% of dry weight (DW). Ankistrodesmus falcatus, Ankistrodesmus sp., Chlorococcum wemmeri, Coenocystis sp., Isocystis sp., Lyngbya bergei, Oscillatoria amphibia, Polytoma papillatum, Scenedesmus protuberans, Scenedesmus sp. and Synechocystis aquatilis showed a high capacity for lipid storage, higher than 20% DW. For carbohydrate contents, only Scenedesmus protuberans and Scenedesmus quadricauda showed an excessive level, compared to other scanned species with 29.21% and 24.76% DW, respectively. Green algae, Scenedesmus protuberans for example, generally tend to synthesize proteins, with a content reaching 45% DW, while blue-green algae, for example Lyngbya bergei, tend to synthesize lipids, with a content reaching 50% DW

Influence of hydro- and osmo-priming on sunflower seeds to break dormancy and improve crop performance under water stress

International audienceThis study explored the effects of two hydro- and osmo-priming durations (8 and 16 h) on growth and yield components of sunflowers (Helianthus annuus L.) under water stress. The pot experiment, performed under a rain shelter, consisted of 9 treatments replicated five times: unprimed seeds as control (C), hydro-primed seeds (T0), osmo-primed seeds in 10, 20, and 30% PEG-6000 (T1, T2, and T3, respectively). Severe water stress was applied for 12 days to all treatments at the beginning of the flowering stage. Statistical analysis revealed a very highly significant positive effect (p < 0.01) by all treatments on sunflower seed germination compared with the control. Moreover, primed seeds improved significantly for all growth parameters and yield components, but no significant differences were observed according to either priming technique or duration. The highest value of germination capacity, for fresh and dry biomasses, was obtained with PEG-primed seeds at 10% for 16 h. The grain number per anthodium and grain yield per plant from primed seeds were higher than those in the control (1.9- to 2.5-fold and 2.8- to 3.3-fold respectively). Under conditions of water stress, the proline content in primed plants was significantly higher than that in unprimed ones, with the exception of T3 treatment primed for 8 h. Soluble sugars and chlorophyll contents increased significantly with all applied treatments compared with the control. The study showed that the applied priming treatments improved germination characteristics in particular and increased growth and yield components for sunflowers under drought stress conditions

Assessment of nitrogen and phosphate balance and the roles of bacteria and viruses at the water-sediment interface in the Allal El Fassi reservoir (Morocco)

International audienceBalances of nitrogen and phosphate were studied in the Allal El Fassi reservoir (Morocco); the results showing that nitrogen input (296 mg m−2 d−1) was 161 % higher than output (183 mg m−2 d−1). Phos-phate input (35.65 mg m−2 d−1) was 865 % higher thanoutput (4.12 mg m−2 d−1), causing a progressive increase in the internal phosphate stock. Sedimentation flux was equally high (53.80 and 18 mg m−2 d−1) for both nitrogen and phosphate input, mainly from the Sebou River and in particulate form which immediately settles upon arrival in the reservoir. The release of nitrogen and phosphate from the sediment (5.40 and1.15 mg m−2 d−1, respectively) depended on physico-chemical and biological (bacteria and viruses) variability and the calcareous nature of the catchment basin. Calcium-bound phosphate prevailed in the reservoir. Drastic control of phosphate input is suggested to avoid accumulation of calcium-bound phosphate which may dissociate and thereby contribute to eutrophication