Impact of Anthropogenic Pressures on the Physicochemical Characteristics and Sediment Composition of Oubeira Lake (El Kala National Park)

Oubeira Lake is a shallow freshwater body covering approximately 21.73km² of wetlands in northeastern Algeria. Listed as a Ramsar site since 1983, it lies within the El Kala National Park. This endorheic aquatic system receives wastewater from small surrounding settlements and is subject to overexploitation for agricultural purposes, especially under drought conditions. These anthropogenic pressures significantly impact the lake’s physicochemical characteristics, leading to water level decline, increased turbidity, and altered biodiversity. Local fishers report annual changes in fish stock availability, strongly linked to water level fluctuations affecting biomass reproduction. To assess the presence of exchangeable trace metals (ETMs) in the lake's sediments, 24 sampling stations were surveyed along six transects, with three additional stations representing major tributaries. The study focused on both exchangeable bases and specific ETMs, including aluminum (Al), iron (Fe), manganese (Mn), calcium (Ca), magnesium (Mg), sodium (Na), and potassium (K). Analytical results were statistically treated using Principal Components Analysis (PCA), a robust method that enables the identification of key variables relevant for environmental modeling.