Ecologie et distribution des paramètres physico-chimiques et du phytoplancton dans les réservoirs de la région de Mila: cas de barrages de béni Haroun

Abstract

his study evaluates the ecological status of Béni Haroun Dam (Mila Province), the largest water reservoir in Algeria with a storage capacity of 2.5 billion m³. The research aimed to assess water quality through the combined analysis of physicochemical parameters and phytoplankton communities. Sampling was conducted at 5 stations across the reservoir. Water temperatures ranged from 28°C to 29°C (mean 28.4°C), the pH was alkaline (mean 8.88), and average turbidity measured 24.6 NTU. A total of 13 phytoplankton genera were identified, spanning 5 phyla and 8 classes. The dominant taxa were Oocystis (38.67%), Spirogyra (25.33%), and Ceratium (13.33%), with Spirogyra occurring in 80% of the stations. The Shannon diversity index ranged from 0.56 to 1.55 bits, with the highest value recorded at station S1. Maximum cell abundance reached 33 individuals at station S2. Principal Component Analysis (PCA) revealed strong correlations between environmental parameters (nutrients, temperature, turbidity) and phytoplankton distribution. The findings highlight the influence of anthropogenic pressures (e.g., agricultural runoff, wastewater) on the reservoir's trophic state. The study recommends implementing an integrated and sustainable management strategy to prevent eutrophication and preserve essential ecosystem services.