Distribution of black fungus gnats (Diptera, Sciaridae) in Morocco, with an updated list of species and an emphasis on Moroccan crop pest species

The present work deals with the spatial distribution of the sciarid species (black fungus gnats) recorded from Morocco throughout the major biogeographical regions: Rif, Eastern Morocco, Atlantic Plain, Middle Atlas, High Atlas, and Anti-Atlas, providing for the first time an atlas of the distribution of Moroccan sciarid fauna. The analysis of the species distribution showed differences between the regions, revealing that the High Atlas and the Rif hosted the greatest specific richness. Of the surveyed sites, forests, crop fields, and aquatic habitats seem to be the most favourable for supporting many sciarid species. Ecological preferences for each species are discussed, indicating a clear preference for medium altitudes ranging from 500 to 1000 m. Alongside the study on the distribution of species, a review of the species recorded in Morocco and gathered from the literature has enabled us to update the checklist of sciarid species, which comprises 65 so far in Morocco. Particular emphasis focused on black fungus gnats considered potentially harmful, with the aim of assessing their distribution in the country, has revealed that Bradysia transitata, B. trivittata, B. xenoreflexa, Lycoriella sativae, Scatopsciara subarmata were collected from strawberry greenhouses (Rosaceae: strawberries), Bradysia placida, B. santorina, B. scabricornis, B. tilicola, B. trivittata and Camptochaeta jeskei were collected from fruit trees (Rosaceae: almond trees), Bradysia santorina, Corynoptera saccata and C. semipedestris were found on palms (Arecaceae: date palms), Scatopsciara atomaria and S. curvilinea were captured in crop fields (Poaceae, Fabaceae), Bradysia scabricornis, Bradysiopsis vittata were collected from Liliaceae, Scatopsciara atomaria was also found on Asteraceae and Solanaceae, and Corynoptera praeparvula was exclusively reported from Solanaceae

Impact de la sécheresse sur l'évolution de la qualité des eaux du lac Mansour Eddahbi (Ouarzazate, Maroc)

L'objectif de ce travail est d'étudier l'impact d'une année hydrologique très sèche (98/99) sur la qualité physico-chimique et l'évolution de l'état trophique du lac Mansour Eddahbi. Ce lac est situé dans la région de Ouarzazate, au sud du Maroc, caractérisée par un climat aride continental, avec des écarts thermiques hiver-été importants, des précipitations très faibles et une forte évaporation. Ceci induit une réduction considérable du volume total du lac et par suite une baisse de 14 m de son niveau.À la lumière des valeurs de températures enregistrées au niveau de la colonne d'eau, le lac peut être classé dans la catégorie des lacs monomictiques avec une seule période de mélange hivernale. Le pH est légèrement alcalin. La réduction du volume d'eau au niveau du lac a engendré une augmentation de la salinité des eaux. Une corrélation significative est enregistrée entre les deux paramètres (r2 =0,60 pour n=13 et p<0,05).Un déficit marqué en oxygène dissous (7,3 mg d'O2 /l comme moyenne en surface et des valeurs inférieures à 2 mg d'O2 /l voire nulles en profondeur durant la stratification), les teneurs en Chl "a" (24 µg/l) permettent de classer le lac dans la catégorie des lacs eutrophes. Selon les teneurs enregistrées en azote (0,2 mg/l) et en phosphores (0,02 mg/l), le lac est hyper-eutrophe. Deux années auparavant, le lac était considéré comme mésotrophe (ONEP/BRL, 1998). Les conditions climatiques sévères qui ont sévi durant l'année hydrologique 98/99 ont contribué à une évolution accélérée de l'état trophique du lac.Eutrophication is one of the most important water quality problems in lakes. Due to the effects of excessive external inputs of nutrients (phosphorus and nitrogen), compounded with unfavorable climatic and hydrologic conditions, the lake undergoes major changes that involve both the physical-chemical properties of water and the aquatic communities living there. There have been many studies on lake ecosystems and their evolution (HENRY et al., 1984; AFDALI, 1993; HARRAK, 1991; LOUDIKI et al., 1994; SBIYYAA, 1998, MOUHRI et al., 1999). These studies relate especially to the role of nutrients (nitrogen and phosphorus mainly) in the evolution of lakes. The influence of climatic and hydrologic conditions on the structure and dynamics of these ecosystems has been often underestimated. Indeed, there are few studies on the relationship between climatic conditions and the trophic status of aquatic ecosystems.The aim of this paper is to study the behavior of the physical-chemical qualities of water in lake Mansour Eddahbi (Ouarzazate, Morocco) and its trophic status under severe climatic conditions, especially during the very dry hydrological year 1998/99. The Ouarzazate region is characterized by an arid continental climate with very hot summers and cold winters. Due to both great evaporation and increasing demand for water for irrigation, the water levels of the reservoir has been reduced by 14 m and its storage capacity has been considerably reduced. The approach used was to assess water quality in a station at the deepest area of the lake during the hydrological year 1998/99. Sampling was undertaken monthly and different parameters were analyzed including temperature, pH, total suspended solids (TSS), salinity, dissolved oxygen (DO), chlorophyll a, phosphorus (TP and PO43-), and nitrogen (TNK, NO3 - and NH4 +).The results of this study demonstrated important seasonal variations of water temperature in the lake. Temperature varied from 9.5°C in the winter to as high as 28.5°C in the summer. Based on this parameter, the reservoir could be classified as a monomictic hot lake with one mixing period occurring in winter. In the entire water column, the pH values were slightly alkaline and oscillated between 7.8 and 8.5 at the surface and 7.4 to 8.2 at the bottom of the lake. This reflects a well-buffered system with moderate benthic decomposition activity. The decrease in water volume by evaporation and intensive use for irrigation resulted in an increase in water salinity. These two parameters presented a significant correlation (r2 =0.60 for n=13 and p<0.05). A decrease in dissolved oxygen from 7.3 mg O2 /l at the surface to 0 mg O2 /l at the bottom of the lake occurred during summer stratification. However, water of the lake reservoir was well oxygenated during preceding years (concentration of dissolved oxygen oscillated between 2 and 11 mg/l (ONEP/BRL, 1998)). Concentrations of chlorophyll a in the euphotic zone (8 m depth) were very important and varied from 12 µg/L (August 1998) to 49 µg/L (September 1999) with an average of 25 µg/L. Based on the chlorophyll a value, the lake Mansour Eddahbi could be classified as eutrophic.The lake has become shallower and the thermocline, beginning at 12 m below the surface, has moved closer to the deeper layers where exchange between sediments and the water column is important. These exchanges between the two compartments of the lake contributed to enrichment of the water column in summer, creating an internal nutrient load. During the hot period when the lake was stratified, there was a large loss of nitrogen from the system. During the mixing period, nitrates were present at substantial concentrations in the deeper regions, but in summer nitrates were consumed rapidly in the surface layer, leading to a limitation on phytoplankton growth in this period. This same phenomenon was also noticed by HENRY et al. (1984). Furthermore, these losses of nitrogen induce a strong reduction in the N/P ratio during this period.Orthophosphate concentrations decrease from the bottom layers to the surface, with almost total impoverishment in the upper strata. This impoverishment reaches 10 m during the summer period and these values are often limiting for the phytoplankton production. The correlation obtained between orthophosphate concentrations and chlorophyll a was significant, especially in summer (r2 =0.79 for n=13 and p<0.05).Nutrient exchange at the water and sediment interface was favoured by the anoxic conditions at the lake bottom that prevailed during the eight months of stratification. The release of these substances can alone, without external contributions, maintain important primary production. This was confirmed by the importance of phytoplankton development compared to the preceding years. The algae production seemed to be enhanced, even if the reported N/P ratio was not optimal, particularly during the period of stratification and had no significant correlation with chlorophyll a content (r2 =0.19, n=13 and p<0.05). This important production appeared to be the result of an internal enrichment of the lake in nutrients coming from the sediment. According to nitrogen (0.2 mg/L) and phosphorus values (0.02 mg/L), the lake could be classified as hypereutrophic whereas two years earlier it was considered mesotrophic (ONEP/BRL, 1998). This work shows clearly that the severe climate conditions during the hydrological year 1998/99 contributed to a rapid degradation of the trophic status of this lake. It changed from a mesotrophic to a hypereutrophic state, resulting from an important enrichment in nutrients and the consequent algal production

Caractérisation physico-chimique des argiles fibreuses de « Souk el Arbaa » du Gharb, Maroc

Le présent travail s’intéresse à l’étude de la qualité industrielle des argiles fibreuses de ‘Souk El Arbaa’ du Gharb appartenant à l’étage géologique Eocène-Miocène. Cette étude a révélé à travers l’analyse d’une vingtaine d’échantillons, prélevés sur des niveaux marneux variés, par spectrométrie à fluorescence X une carence en fer, une richesse en CaO, des taux plus ou moins élevés en Al2O3. La diffractométrie aux rayons X a permis de mettre en évidence une composition minéralogique assez variée dans les différents échantillons analysées, dominée par la présence de paragenèses minéralogiques composées de calcite, dolomite, quartz, sépiolite et attapulgite (argiles fibreuses). Ainsi, le chimisme des échantillons analysés indique d’une façon inéluctable que les argiles de ‘Souk El Arbaa’ du Gharb nécessitent un traitement afin de les rendre exploitables pour la production de céramique d’excellente qualité.Mots-clés : qualité industrielle, argiles fibreuses, Eocène-Miocène, céramique, Maroc

Variations saisonnières des formes de phosphores dans une station de traitement des eaux usées par lagunage, sous climat aride de Marrakech (Maroc)

L'objectif de ce travail est d'étudier dans un premier temps la dynamique du phosphore dans un système de traitement d 'eaux usées par lagunage facultatif, en relation avec les compartiments biologiques: phytoplancton, zooplancton et bactéries, dans un deuxième temps, d'évaluer, sous les conditions du climat aride, les performances épuratoires de ce système en ce qui concerne les formes du phosphore. Un intérêt particulier est porté au phénomène du relargage du phosphore par les sédiments. Les résultats montrent qu'il y a une évolution saisonnière et cyclique du phosphore dans les bassins de lagunage, en étroite corrélation avec le phytoplancton et le zooplancton. Le phytoplancton représente la part importante des formes organiques du phosphore particulaire. Les meilleures performances d'élimination du phosphore sont notées au printemps (77% pour les PO4 et 64 % pour le phosphore total). La période la moins performante est la période automne-hiver où les rendements moyens ne dépassent pas 38%. Le phosphore éliminé est stocké dans les sédiments. En période estivale, des phénomènes de relargage du phosphore à partir des sédiments ont été mis en évidence, favorisés par une zonation verticale des eaux à cette période. Des essais aulaboratoire ont montré la grande aptitude des sédiments de la station de lagunage étudiée à relarguer le phosphore, avec intervention de l'activité biologique du sédiment.Assimilation, sedimentation and release are the principal mechanisms controlling the behavior of phosphorus in aquatic ecosystems. There are numerous investigations of the phosphorus cycle in lakes and rivers in relation to the eutrophication process. There are, however, few studies about phosphorus cycling in waste stabilization ponds and most of these have discussed phosphorus removal. The aims of this paper were: 1) to study phosphorus dynamics in relation to the biomass compartment (zooplancton, phytoplancton and bacteria); and 2) to evaluate the phosphorus removal efficiency of the treatment plant under arid climatic conditions. Of particular interest was the remobilization of phosphorus from the pond sediment, both under laboratory conditions and in the field. The experimental installation consisted of two ponds receiving domestic wastewater (mean flow=120.4+5.8 m3.day-1 and specific organic load=56 kgBOD.ha-1. day-1; pond area=0.5 ha and depth=1.5 m). Samples were taken twice monthly from the surface, B1(S) and B2(S), and from the 1.5 m layers, B1(F) and B2(F). Composite (24 h) samples were taken from the inflow and the outflowof the plant to determine the removal efficiencies. In each sample, soluble reactive phosphorus (PO4), total phosphorus (PT) and total soluble phosphorus (PTD) were determined. Particulate phosphorus (PTP) was calculated as (PT-PTD) and soluble organic phosphorus (POD) as (PTD-PO4). Phosphorus release was measured in a plexiglas flask containing sediment (collected by corer from the pond bottom) overlaid with distilled water. Over 15 days, daily measurements were made of PO4 and total phosphorus. Sediment dry weight (%), volatile matter, organic carbon (%) and total phosphorus were measured before and after each test. Phosphorus contents of the phytoplankton, zooplankton and bacteria were estimated using the methods of BOUGIS (1974).The results show that cyclical and seasonal variations of phosphorus content were closely correlated with variations in the biological components. Significant correlation coefficients were noted between chlorophyll-a and particulate organic phosphorus. Organic phosphorus in algal cells was the more important form of particulate organic phosphorus. Under the arid climate, the waste stabilization ponds were more efficient at phosphate removal during the spring-summer period (77% of PO4 and 64% of total phosphorus in spring). The first pond may play the major role in phosphate removal. Phosphorus is only eliminated from stabilization ponds through accumulation in the sediment. However, part of the phosphorus which accumulates in pond sediments remains potentially mobile. During the summer period, phosphorus release from the sediment, observed in situ, was favored by stratification of the overlying water. The same phenomenon was noted during the autumn, particularly the release of POD. Laboratory studies have shown that phosphorus release may amount to 55 mg P m-2d-1. Biological activity may play a significant role in this mobilization

Comparative pathogenicity of Colletotrichum spp. against different varieties of strawberry plants (Fragaria ananassa) widely grown in Morocco

The evolution of anthracnose symptoms on the aerial part (leaves, stems and strawberries) of three varieties Fortuna, Camarosa and Festival of strawberry plants inoculated with the conidial suspensions of Colletotrichum acutatum and Colletotrichum gloeosporioides isolates was followed. The severity index and infection coefficients increased in function of time. Seven days after inoculation they were low not exceeding 13.43% and 43.33, but they increased four weeks after inoculation, respectively, to 37.96% and 99 on strawberry plants of the Camarosa variety, 54.44% and 105 on those of Fortuna and 51.12% and 85 on those of Festival. At the sixth week, the severity index and infection coefficients became very high, reaching respectively 100% and 408 on Fortuna plants inoculated with C. gloeosporioides isolate (Coll3) followed by Coll2 (89.28% – 300), Coll1 (86.66% – 378) and Coll4 (80.45% – 198) of C. acutatum species. Similarly, the isolate Coll3 caused fruit rot; the percentage of rotten strawberries was 100% on Fortuna variety, 83.33% on Festival and 70.25% on Camarosa. A positive re-isolation of the tested Colletotrichum isolates has been noted from leaves of strawberry varieties and negative from crowns or the roots. A significant to moderate reduction in fresh and dry weights of the aerial part and roots was noted in inoculated strawberry plants compared to the control

The Investigation of third-order hyperpolarizabilities and susceptibilities of push-pull azobenzene polymers

International audienc

Anévrysme et Pseudo-anévrysme du ventricule gauche

La gravité de l’infarctus du myocarde réside dans ses complications. Certainement, on avait une importante réduction dans leurs incidences grâce  à  l’amélioration de la prise en charge médicale et l’avènement des méthodes de reperfusion précoce, mais il persiste un taux considérable de complications qui posent un problème diagnostic mais surtout thérapeutique. Parmi eux, il existe l’anévrysme et le pseudo-anévrysme du ventricule gauche. Ces deux complications relativement rares sont souvent méconnues, d’où l’intérêt d’en connaître les modalités de prise en charge diagnostique et thérapeutiques

Olive phenology as a sensitive indicator of future climatic warming in the Mediterranean

Experimental and modelling work suggests a strong dependence of olive flowering date on spring temperatures. Since airborne pollen concentrations reflect the flowering phenology of olive populations within a radius of 50 km, they may be a sensitive regional indicator of climatic warming. We assessed this potential sensitivity with phenology models fitted to flowering dates inferred from maximum airborne pollen data. Of four models tested, a thermal time model gave the best fit for Montpellier, France, and was the most effective at the regional scale, providing reasonable predictions for 10 sites in the western Mediterranean. This model was forced with replicated future temperature simulations for the western Mediterranean from a coupled ocean-atmosphere general circulation model (GCM). The GCM temperatures rose by 4·5 °C between 1990 and 2099 with a 1% per year increase in greenhouse gases, and modelled flowering date advanced at a rate of 6·2 d per °C. The results indicated that this long-term regional trend in phenology might be statistically significant as early as 2030, but with marked spatial variation in magnitude, with the calculated flowering date between the 1990s and 2030s advancing by 3–23 d. Future monitoring of airborne olive pollen may therefore provide an early biological indicator of climatic warming in the Mediterranean

Diversity of endomycorrhizal fungi in the rhizosphere of chickpea in Morocco

The endomycorrhizal fungi diversity in the rhizosphere of chickpea (Cicer arietinum L.) and the evaluation of root mycorrhizal level were studied in six regions of Morocco: Tahla, Sefrou, Souk Larbae, Souk Tlat, Ouazzane and Jarf Melha. All chickpea roots are carrying endomycorrhizal structures. Root mycorrhizal parameters varied from one site to another, and the highest frequency and intensity of mycorrhization was recorded in the roots of chickpea plants at the two sites Tahla and Jarf Melha respectively, 83%, 33% and 25.03%. In addition, the highest arbuscular content was also noted in the roots of plants growing in the site of Tahla (22.18%) while the lowest content was noted at the site of Sefrou (2.07%). However, the vesicles were not observed in all the sites. The highest numbers of endomycorrhizal spores were recorded in the rhizosphere of plants collected in Jarf Melha and Tahla, respectively, 74 and 41 spores / 100 g soil. All spores found in the studied sites are represented by 22 morphotypes belonging to 7 genera: Glomus (13 species), Acaulospora (4 species), Gigaspora (one species), Radekera (one species), Entrophospora (one species), Pacispora (one species), Dentiscutata (one species)