New Jurassic amber outcrops from Lebanon

International audienceAmber predating the Lower Cretaceous is extremely rare. During the past two decades, records of discoveries of amber sites have increased considerably worldwide. We report herein the discovery of ten new outcrops of amber from the Late Jurassic in Lebanon, in addition to other nine outcrops described by Azar et al. (2010). Some of these outcrops gave large centimetric sized amber pieces. Each of these new amber outcrops is described, and its infrared spectrum is given. Though the Jurassic amber yielded to date no more than some fungal inclusions, this discovery is significant and promising especially in the reconstruction of the paleoenvironment

Lead bioaccumulation in Opuntia ficus-indica following foliar or root exposure to lead-bearing apatite

International audienceThe contamination of edible leafy vegetables by atmospheric heavy metal-bearing particles is a major issue in environmental toxicology. In this study, the uptake of lead by cladodes of Opuntia ficus-indica (Ofi), traditionally used in Mexican cuisine and in livestock fodder, is investigated after a 4-months exposure of either cladodes or roots to synthetic Pb-fluorapatite particles. Atomic Absorption Spectroscopy (AAS) for the quantitative analysis of Pb levels, Scanning Electron Microscopy coupled with Energy Dispersive X-Ray Spectroscopy (SEM-EDX) for the examination of the cladode surface and fate of particles, and Micro-X-ray fluorescence (μXRF) measurements for elemental mapping of Pb in cladodes, were used. The results evidence that foliar contamination may be a major pathway for the transfer of Pb within Ofi cladodes. The stomata, areoles, and cuticle of cladode surface, play an obvious role in the retention and the incorporation of lead-bearing apatite, thus revealing the hazard of eating contaminated cladodes. The possibility of using series of successive cladodes for biomonitoring the atmospheric pollution in arid and semi-arid regions is also rapidly discussed

Air pollution biomonitoring using successive cladodes of Opuntia ficus-indica : A lead isotopic study

International audienceOpuntia ficus-indica (Ofi) is a long-domesticated cactus that is widespread throughout arid and semiarid regions of the world. Ofi is grown for both its fruits and edible cladodes, which are flattened photosynthetic stems. Young cladodes develop from mother cladodes, thus forming series of cladodes of different ages. Therefore, successive cladodes may hold some potential for biomonitoring over several years the local atmospheric pollution. In this study, cladodes, roots, dust deposited onto the cladodes, and soil samples, were collected in the vicinity of three heavily polluted sites, i.e. Selaata fertilizer industry (Lebanon), the roadside of a highway near Saida (Lebanon), and the tailings of an abandoned lead-zinc mine (Jebel Ressas in Tunisia). The lead content was analyzed by Atomic Absorption Spectroscopy and ICP-MS, Scanning Electron Microscopy coupled with Energy Dispersive X-Ray Spectroscopy (SEM-EDX) was used to characterize the cladode surfaces and the nature of dust deposit, and the lead isotopes were analyzed to identify the origin of Pb. The results show that (i) Ofi readily bioaccumulates Pb, (ii) the lead isotopic composition of cladodes evidences a foliar pathway of lead into Ofi and identifies the relative contributions of local Pb sources, (iii) the evolution of air quality is effectively recorded with successive cladodes, which makes Ofi a promising biomonitor to be used in environmental and health studies

Trace metals in phosphate fertilizers : Cadmium behavior in Lebanese soils

National audienc

Upgrading Pyrolytic Oil via Catalytic Co-Pyrolysis of Beechwood and Polystyrene

International audienceThis study aims to investigate the catalytic co-pyrolysis of beech wood with polystyrene as a synergic and catalytic effect on liquid oil production. For this purpose, a tubular semi-continuous reactor under an inert nitrogen atmosphere was used. Several zeolite catalysts were modified via incipient wetness impregnation using iron and/or nickel. The liquid oil recovered was analyzed using GC-MS for the identification of the liquid products, and GC-FID was used for their quantification. The effects of catalyst type, beechwood-to-polystyrene ratio, and operating temperature were investigated. The results showed that the Fe/Ni-ZSM-5 catalyst had the best deoxygenation capability. The derived oil was mainly constituted of aromatics of about 92 wt.% for the 1:1 mixture of beechwood and polystyrene, with a remarkably high heating value of around 39 MJ/kg compared to 18 MJ/kg for beechwood-based bio-oil. The liquid oil experienced a great reduction in oxygen content of about 92% for the polystyrene–beechwood 50-50 mixture in comparison to beechwood alone. The catalytic and synergetic effects were more realized for high beechwood percentages as a 75-25 beechwood–polystyrene mix. Regarding the temperature variation between 450 and 600 °C, the catalyst seemed to deactivate faster at higher temperatures, thus constituting a quality reduction in the pyrolytic oil in high-temperature ranges

Two-step formation mechanism of Acetobacter cellulosic biofilm: synthesis of sparse and compact cellulose

International audienceClassical studies concerning “Acetobacter xylinum” focus on bacterial cellulose “BC” yield and rate in broth, after a long period of incubation (7–14 days). Such observations do not highlight bacterial physiology in the first incubation hours and its impact on BC production. In this study, the growth of a wild strain of Acetobacter was monitored in the first incubation hours. We showed the presence of two different physiologies; the first extends from the incubation moment till the formation of a sparse BC. Sparse BC modifies surface viscosity, and stabilizes hydrodynamic conditions to initiate compact BC production that marks the second physiology. Two containers, of different shapes, were used to confirm our findings, one of which is a culture tube with high drift currents on the broth-air interface, and the other is a conical flask with more stable hydrodynamic conditions at the culture’s surface. We showed that Acetobacter always follows two physiologies independent of the container shape. Logistic model, FTIR, XRD and SEM analysis are used to confirm the results

New Jurassic amber outcrops from Lebabon

International audienceReports of amber of occurrence predating the Lower Cretaceous are extremely rare. During the past two decades, records of discoveries of amber sites have increased considerably worldwide, consequently to the alertness by the scientific community of the importance and conservational pristine quality of the amber. Lebanon is weil known to contain abundant Lower Cretaceous amber outcrops (more than 400 localities). A number of these outcrops yielded the oldest amber containing intensive biological inclusions. We report herein the discovery of nineteen outcrops of amber from the Late Jurassic in Lebanon. Sorne of these outcrops gave large centimetric sized amber pieces. These new amber sites are ail located in the Northern part of Mount Lebanon in volcano-Iateritic Late Jurassic deposits (Kimmeridgian age, circa -150 Million Years). The amber is found in lens of lignite mixed with laterites and pyrite that occupy pits in a volcano-basaltic complex sail. The characterization of these Late Jurassic ambers is performed by studying their chemical constitution via FTIR (Fourier Transform InfraRed) spectroscopy. Though the new Jurassic amber yielded to date no more than some fungal inclusions, but the discovery of such material is very significant and promising especially in the reconstruction of the paleoenvironment. It also opens great prospects to reveal hopefully some Late Jurassic fossil arthropods

Disruption of biofilms from sewage pipes under physical and chemical conditioning.

International audienc

Culture medium pH influence on Gluconacetobacter physiology: Cellulose production rate and yield enhancement in presence of multiple carbon sources

International audienceGluconacetobacter genera are valued for bacterial cellulose (BC) and acetic acid production. BC is produced at optimal yields in classical microbiological media that are expensive for a large scale of production. In addition, BC usage for industrial purposes is limited due to low conversion rate into cellulose and to long incubation duration.In this paper, Gluconacetobacter isolated from apple vinegar was kinetically studied to evaluate cellulose production in presence of different carbon sources. Acetic and citric acid effect on Gluconacetobacter metabolism is clarified. It was shown that Gluconacetobacter uses glucose as a primary carbon source for cells growth and products formation. Acetic acid employment as a co-carbon source in Hestrin Schramm medium showed an increase of 17% in BC yield with a moderate decrease in the crystallite size of the resulting polymer

Hydrodynamic influence on reservoir sustainability in semi-arid climate: A physicochemical and environmental isotopic study

Water scarcity and increasing water demand require the development of water management plans such as establishing artificial lakes and dams. Plans to meet water needs are faced by uprising challenges to improve water quality and to ensure the sustainability of hydro-projects. Environmental isotopes coupled to water physicochemical characteristics were investigated over a biennial cycle to assess both geomorphological and environmental impacts on the water quality of a reservoir situated in an intensively used agricultural watershed under a Mediterranean semi-arid climate. The particularity of the semi-arid climate and the diverse topography generate a continental and orographic rain effect on the isotopic composition of precipitation and the water recharged sources. The studied reservoir responds quickly to land-use activities and climatic changes as reflected by temporal and spatial variations of water chemistry and isotopic composition. Increasing changes in precipitation rate and dry periods significantly modified the water isotopic composition in the reservoir. During the first year, hydrogen (δD) and oxygen (δ18O) isotopes are depleted by 6 and 2‰ between dry and wet season, respectively. While a shift of −2‰ for δD and −1‰ for δ18O was detected during the second annual cycle. Environmental isotopic compositions demonstrate for the first time the occurrence of groundwater inflow to the central (Cz) and dam (Dz) zones of the Qaraaoun reservoir. The Cz and Dz can be considered as open water bodies subjected to dilution by groundwater inflow, which induces vertical mixing and reverse isotopic stratification of the water column. In the contrary, the river mouth zone acts as a closed system without groundwater intrusion, where heavy water accumulates and may act as a sink for contaminants during dry season. Groundwater influx acts as a dilution factor that renews the hypolimnion, and minimizes the perturbations induced by both internal biogeochemical reactions and external hydrological variations. Attention should be devoted to the hydrogeological location of planned reservoirs, which should take into account the vicinity of shallow water table to insure good water quality and water sustainability.SCOPUS: ar.jinfo:eu-repo/semantics/publishe