The current study aims to investigate the median lethal concentration (LC50 at 96 h) of lead for the female sea urchin Paracentrotus lividus. Adult urchins were exposed to six gradually increasing concentrations (0.5, 1, 2, 4, 8 and 10 mg/L) of lead for 96 h. The mortality of the urchins was directly proportional to the lead concentration, and the LC50 value at 96 h was 3.6 mg/L. Additionally, lead concentration and the bioconcentration factor (BCF) in the gonads of control sea urchins and urchins exposed to two selected concentrations (0.5 and 1 mg/L) were determined after 96 h of exposure. The results showed high levels of this metal in the gonads of P. lividus, with BCF values of 35.59 and 92.85 for the two concentrations, respectively. In addition, the effects on non-enzymatic and enzymatic biomarkers, vitellogenin (VTG), glutathione (GSH) and catalase (CAT), were evaluated at baseline (0 h), 24, 48, 72 and 96 h of exposure under laboratory conditions. The results demonstrated significant decreases in CAT activity, as well as in GSH and VTG levels, compared with those of the control. These findings suggest that acute exposure to lead can cause deleterious effects on the survival, reproductive and physiological aspects of P. lividus, which varied depending on the degree of pollution.

Environmental pollution is one of the most significant issues in industrial regions.Land snails are commonly used as suitable organisms to monitor environmental pollution.Therefore, the present study aims to investigate the effects of anthropogenic pollution on biochemical biomarkers in land snails, Cantareus aspersus.Snails were obtained from four sites of northeastern Algeria, namely El-Hadaiek, Azzaba, Ben-Azzouz (Skikda city) and El-Kala (El-Taref city).The sites of Skikda city were selected in this study because of their proximity to industrial factories, while the El-Kala site was used as a reference site (control site) for its far location from pollution sources.Moreover, the enzymatic activities of glutathione S-transferase (GST) and acetylcholinesterase (AChE), and the three energy reserves (glycogens, lipids and proteins) were measured in the digestive gland of snails collected from each site during the winter and spring seasons.The results revealed a significant variation in the AChE activity and energy reserves between sites and seasons, along with significant correlations between the enzymatic and non-enzymatic biomarkers.The highest activity of GST and total proteins were observed during spring in snails of Azzaba site, identified as the closest site to potential pollution sources.In addition, AChE activity was significantly decreased during spring, as well as depletion of lipid and glycogen contents with the highest values was recorded in the site of Azzaba.Conclusively, the land snails, C. aspersus are proven as sentinel organisms effectively used in biomonitoring of terrestrial environment in Skikda region.

Background The inventory process is the first method to protect and safeguard animal biodiversity. This study carries out a quantitative and qualitative inventory of terrestrial gastropods at three sites in Skikda province (north-eastern Algeria). The relationship between terrestrial gastropod diversity and soil physicochemical factors was investigated using statistical analyses. Results The inventory data reveals the presence of four families and eight species showing varied predominance rates of Cornu aspersum species according to each site in the city of Skikda (Azzaba 53.88%; Ben-Azzouz 56.12%; El-Hadaiek 37.92%). The maximal specific richness was registered in the El-Hadaiek site (seven species), and the highest mean richness was noted in the Ben-Azzouz site (392 individuals). Of the eight gastropod species identified, three species ( Cornu aspersum, Cantareus apertus and Rumina decollate ) were classified as constant species. The Shannon–Weaver diversity and equitability indices vary by site. Conclusion The presence of certain species in one site and their absence in other sites, as well as the variation in ecological indices, could be attributed to the effect of soil-physicochemical factors.

The present study was designed to investigate the proximate (moisture, dry matter, ash, and fat content) composition and metallic element contents (Ca, Zn, Fe, and Cd) in an edible Bivalve, Donax trunculus from the gulf of Annaba, and to evaluate the effect of cadmium (Cd) on these parameters. The clams were collected from the El-Battah site during the morphologically ripe and reared stages under laboratory conditions. Physicochemical parameters of seawater samples including temperature, pH, salinity, and dissolved oxygen were determined. Cadmium at two sub-lethal concentrations (LC10 and LC25-96h as determined previously) was added to the rearing water. The results revealed significant effects of Cd concentrations, exposure time, and sex on all the studied parameters. Indeed, the contents of dry matter, fat and metallic elements, excluding Cd were significantly decreased, while the moisture, ash, and Cd contents were significantly increased in both sexes at two sub-lethal concentrations. Moreover, the measurement of proximate composition and minerals contents in D. trunculus could be a very useful approach to evaluate the nutritive value changes in case of exposure to cadmium contamination, and subsequently to avoid health-associated problems.

Summary The Algerian oil and gas industry in recent years has become more focused on tight reservoirs with potenntially large hydrocarbon content. The role that surface seismic can play in identifying better fracture distribution zones, density and orientations, as an alternative to exploration via drilling and hydraulic fracturing, may be more suitable for operators in this region. As onshore seismic acquisition moves to high-density full-azimuth broadband data as a standard an integrated approach to the data processing with workflows and procedures is also required to enable azimuthal AVO inversion and fracture detection studies. In this abstract we discuss the key aspects of the acquisition, data processing and reservoir characterisation used in a modern point source point receiver survey acquired in Algeria to enable the extraction of petrophysical information about the reservoir.

This study was aimed to evaluate the physiological reproductive end points (sex ratio, gametogenic cycle) and biological indices (condition index, length–weight relationship) in D. trunculus collected monthly over the year 2016, from two sites of the Gulf of Annaba (Northeast Algeria): El Battah (relatively unpolluted site) and Sidi Salem (polluted site). The results showed that gametogenesis takes place from December to August in both sites, with an autumnal resting phase. Also, the spawning occurred between March and August with two major spawning phases: April and August in El Battah vs May and August in Sidi Salem. The condition index showed a significant decrease in Sidi Salem site and positive correlation with gonad index. Moreover, the sites exert a significant effect on the allometric relationship and no significant effect on sex ratio. The observed reproductive events are discussed with the changes in the biological indices and the levels of pollution in the studied sites.

Summary In land seismic data processing, refracted wave travel-times are widely exploited for solving near-surface characterization challenges. Mainstream approach includes ray-based refraction tomography for velocity model building and data-driven static estimation. Those methodologies, solely relying on refraction picktimes, suffer from picking errors and from the intrinsic non-uniqueness of the refraction inverse problem. In this paper, two innovative solutions for overcoming the limitation of refraction-based techniques are presented. The first is the integration of independent geophysical information into the velocity model building process, achieved through the Simultaneous Joint Inversion (SJI) of refracted and surface waves. The second is a novel processing workflow that exploits refracted travel-times estimated by SJI to improve the original first break picks and, as consequence, the statics. Both the solutions have been applied to a challenging 3D dataset, bringing sensible uplift from industry standard results.

Seasonal changes in biochemical composition of the bivalve Donax trunculus L. (Mollusca, Bivalvia) were studied during eight months from January to August 2009 in the gulf of Annaba. The samples were collected monthly at two sites: El Battah, a site far from any source of pollution, and Sidi Salem, a site located near human and industrial wastes. The amounts of carbohydrate, lipid, and protein were determined in gonad-visceral mass. The monthly amounts of the different components in gonads varied from 33.68 to 118.09 for carbohydrates, 6.68 to 44.45 for lipids and 3.56 to 36.72 µg/mg of wet tissue for proteins, respectively. A three-way ANOVA indicated significant effects of time, sex, and treatment. Lowest values of components were observed during the spawning phase. There was a significant difference in amounts of these gonad components between the two sites. Globally, the lowest values of carbohydrate and proteins, and the highest values of lipids were recorded in individuals sampled at Sidi Salem.