Phosphorus is a key nutrient regulating algal growth and eutrophication in aquatic systems, yet its isolated effect on microalgae-based wastewater treatment remains underexplored. This study evaluated how varying phosphorus loads drive microalgal community structure and purification performance in controlled photobioreactors fed synthetic wastewater. The synthetic wastewater was formulated with constant carbon and nitrogen but graded phosphorus at C/N/P ratios of 100/5/1, 100/5/10, and 100/5/20 under 6000 lux, a 14 h photoperiod, and 24 ± 2 °C with a 15-day hydraulic retention time. Monitoring of chlorophyll a, pH, total and volatile suspended solids, and algal composition showed that phosphorus enrichment significantly increased chlorophyll a (up to 43.9 µg/L at 20 mg P/L) and particulate biomass (TSS and VSS), while pH remained near neutral to slightly alkaline, with no significant differences among the three bioreactors. Although the same core taxa—Chlorella spp., Scenedesmus spp., Navicula spp., and filamentous algae were present across all bioreactors, their relative abundances shifted significantly with phosphorus concentration. A two-way ANOVA confirmed a highly significant interaction between bioreactor (P level) and genus (p < 0.001), demonstrating phosphorus-driven changes in the microalgal community. Notably, filamentous cyanobacteria (Anabaena spp.) were undetectable in the low- and medium-phosphorus treatments but emerged prominently only at the highest phosphorus level (20 mg/L). Nutrient removal efficiencies peaked in this high-phosphorus bioreactor (C), achieving 85% for bCOD, 78% for nitrogen, and >70% for phosphorus. These results show that phosphorus loading drives predictable shifts in microalgal community composition toward fast-growing algae and cyanobacteria and that these shifts likely contribute to enhanced nutrient removal. The findings support optimization of phosphorus supply and hydraulic residence time in low-cost, sunlight-driven systems to improve polishing performance for small settlements in arid regions.

This study investigates the impact of varying organic carbon loads on the growth, composition, and productivity of microalgae in controlled photobioreactor systems. Three laboratory-scale bioreactors were operated with synthetic wastewater containing different concentrations of Carbon (100, 400, and 800 mgL-1), while maintaining consistent nitrogen and phosphorus inputs. Parameters monitored included pH, chlorophyll a, total suspended solids (TSS), volatile suspended solids (VSS), and microalgal community composition. Microscopic analysis revealed that moderate glucose concentrations (100–400 mgL-1) favored the proliferation of Scenedesmus sp and Chlorella sp, while excessive organic carbon input (800 mgL-1) led to a decline in species diversity and overall algal biomass. Statistical analysis confirmed significant variations in pH, chlorophyll a, TSS, and VSS across treatments, with bioreactor A showing the highest values of algal productivity and pH due to optimal photosynthetic activity. The results demonstrate that moderate organic carbon enrichment enhances algal growth and trophic complexity, while excessive organiccarbon suppresses phytoplankton development, likely due to microbial competition and acidification. These findings provide valuable insights for optimizing organic carbon inputs in algal-based wastewater treatment and ecological restoration strategies.

Olea europaea L. 1753, is one of the oldest and most distinctive trees in the Mediterranean region. Its nutritional, social, cultural, and economic value is very important for populations in arid regions, where it is widely distributed. A sign of a sustainable environment in many agricultural regions is the existence of a wide variety and abundance of arthropod groups. The main objective of the study is to evaluate the diversity of arthropods subservientin in olive agro-systems in the arid region by using several sampling techniques, namely classic sight hunting, visual inspection, Barber pots, and yellow traps. The inventory is carried out over a period of 5 months, from February to June 2023, in three stations in M’Sila (northeastern Algeria). Three classes of arthropods were found: Insecta, Arachnida, and Malacostraca. Captures were numerically dominated by Insecta, representing 96.88% of total captures. Arachnida and Malacostraca classes represented about 2.74 and 0.38%, respectively. During this research, a total of 1861 arthropod individuals were collected and identified into 83 species, 79 genera, 53 families, and 15 orders. The most abundant orders were: Diptera (42.56%), Hymenoptera (28.11%), and Coleoptera (7.32%). However, we found a significant difference in species composition according to habitat (P < 0.01). The species were determined, and the ecological indices were calculated (Shannon Value, Evenness values and Simpson reciprocal index). The dominant functional feeding groups were phytophages (41.91 %), predators (32.94%), and polyphages (22.14%). The arthropods included several olive pests such as Euphyllura olivina (Costa) (Hemiptera: Liviidae), Bactrocera oleae (Rossi) (Diptera: Tephritidae), Prays oleae (Bernard) (Lepidoptera: Praydidae), Liothrips oleae Costa (Thysanoptera: Phlaeothripidae), and Oxycenus maxwelli (Keifer) (Arachnida: Eriophyidae).

The olive fruit fly, Bactrocera oleae, is one of the most destructive pests of olive orchards worldwide, causing substantial economic losses through reduced yield and fruit quality. Effective management of this pest remains a major concern for olive growers due to its high reproductive potential and rapid population buildup under favorable conditions.The present study was carried out in three orchards located in the arid region of M’Sila, Northeast Algeria, from August to December 2023. The objectives were to monitor population dynamics, assess infestation levels, and evaluate control strategies against the olive fruit fly. Adult activity was monitored using McPhail traps baited with food attractants (3% aqueous diammonium phosphate and 3% aqueous ammonium bicarbonate solutions). Pheromone traps were simultaneously deployed for comparative assessment of trapping efficiency. The first adults emerged at the end of August, and the pest continued to emergeuntil the end of December. The first population development peakwas observed in mid-October in all three orchards.Three generations of B. oleae appeared in the M’Sila area. The infestation rates of the pest were38.5% (at Ouled Mansour) and 31.5% (at District Ksob and Ouled Sidi Amor). The McPhail traps (+ 3% ammonium bicarbonate) caught more flies than the McPhail traps (+ 3% diammonium phosphate) and Pheromone traps (Lure - Russell IPM). At every orchard olive site, were observed significant interactions between the week and the trap were observed for the total, male, and female flies. The activity of the fruit flies depended on environmental conditions. Traps baited with ammonium bicarbonate attracted more females.

Background: The apricot tree (Prunus armeniaca L.) is deeply embedded in the agricultural and cultural traditions of the Batna region in northeastern Algeria. It holds significant economic value and is associated with a rich body of traditional knowledge, encompassing a wide range of uses that remain largely undocumented and are at risk of being lost. Methods: Ethnobotanical surveys were conducted from March 2023 to August 2024 in 15 Batna municipalities. Data were collected from 150 local informants using semi-structured interviews and participant observation. Quantitative data were interpreted using ethnobotanical indices such as Use Value (UV), Fidelity Level (FL%), and Informant Consensus Factor (ICF). Results: Prunus armeniaca is a versatile species with profound socio-economic and cultural value in the Batna region. A total of 28 distinct uses were recorded, distributed across four categories: food (56% of use-reports), medicinal (25%), handicraft (11%), and fodder (8%). All parts of the tree are utilized, with the fruit being the most commonly used (92% of informants). Quantitative indices revealed a high overall Use Value (UV = 0.89) and a significant knowledge gap between older and younger generations (p < 0.001). Conclusions: This study provides a crucial baseline record of the traditional knowledge associated with P. armeniaca and highlights the urgent need for its conservation in light of the observed intergenerational knowledge erosion. The findings underscore the species' integral role in local livelihoods and identify potential for developing sustainable value-added products, that could support local economies and help preserve this intangible cultural heritage. Key words: Ethnobotany; Prunus armeniaca, Traditional Knowledge; Quantitative Indices, Batna; Algeria, Conservation

The study of the effect of ecological factors on the physiology and composition of plants is quite significant. Algeria has different bioclimatic zones and ecosystems, leading to varied and specific plant physiology. Each region boasts great biodiversity, with a highly varied composition of metabolites, thus offering a wonderful natural library to discover and exploit. For this reason, our comparative approach aims to analyze existing studies on the essential oil composition of Rosmarinus officinalis in different regions of Algeria and confirm the ecological impact on the species' physiology. Determining the effect of ecological factors on plant physiology and, consequently, on the quantity and quality of metabolites (essential oils) is of practical interest not only to ecologists but also to botanists, chemists, biochemists, and other specialists. This synthetic approach has shown that Rosmarinus officinalis produces different yields of essential oils, as well as varying characteristics for the oils obtained. Therefore, quality and quantity fluctuate based on the ecological factors of the studied region.