Assessment of Water Quality and Nutrient Dynamics in the Mediterranean Lagoon of El Mellah

Adem, Tanca; Aicha Beya, Amira; Raouf, Zaidi; Mounira, Bougdah; Sofiane, Labar

doi:10.21608/ejabf.2025.404827.6368

Assessment of Water Quality and Nutrient Dynamics in the Mediterranean Lagoon of El Mellah

Document Type : Original Article

Authors

¹ Department of Agronomy, Faculty of Natural and Life Sciences, Chedli Bendjedid University

² Department of Marine Sciences, Badji Mokhtar University Annaba

³ Department of marine sciences, Chadli Bendjedid Unversity El Tarf Algeria

⁴ Laboratory of Biogeochemical and Ecological Analyses of Aquatic Environments, Department of Marine Scienbce, University Badji Mokhtar, Annaba, PO Box 12, Sidi- Amar 23005, Algeria.

⁵ Water and environment, faculty of earth sciences geography and territorial planning, houari Boumediene university of science and technology

10.21608/ejabf.2025.404827.6368

Abstract

Coastal lagoons are among the most productive yet vulnerable ecosystems worldwide, facing increasing pressure from human activities and climatic variability. This study evaluated the current physico-chemical status and organic pollution of Lake El Mellah, a Mediterranean lagoon in northeastern Algeria, to provide an updated baseline for environmental management. Water quality was assessed across 15 stations through monthly monitoring of temperature, pH, dissolved oxygen, and key nutrients (NO₃, NH₄, PO₄). Stream discharge and precipitation data were analyzed to interpret hydrological patterns. Results revealed strong seasonal contrasts, with winter rainfall and inflows sustaining higher water renewal, while summer stagnation promoted nutrient accumulation. Nitrate concentrations reached up to 62mg L⁻¹, reflecting agricultural influence, and orthophosphate levels peaked in summer, suggesting sediment release under low oxygen conditions. The organic pollution index indicated moderate to high organic loading, exceeding recommended limits for fishery waters at several sites. This study offers the first comprehensive, seasonally resolved assessment of Lake El Mellah’s nutrient and organic pollution dynamics, highlighting anthropogenic and hydrological drivers of eutrophication. Compared to previous work focused mainly on hydrobiology or biodiversity, this research integrates physico-chemical, hydrological, and pollution indicators, providing an essential reference for long-term monitoring and conservation of Mediterranean coastal lagoons.

Keywords