Nutrient Assessment in the waters of the Oualidia lagoon, Moroccan Atlantic

The Oualidia lagoon is a shallow, nutrient-poor system that suffers from the expansion of oyster farming and agricultural drainage discharges. From an ecological point of view, this lagoon is probably one of the minor conserved wetlands in the Moroccan Atlantic zone. Therefore, the distribution of nutrients (PO43-, NH4+, and NO2-) and physicochemical parameters (temperature, dissolved O2, and salinity) were evaluated for one and a half years. For this purpose, the monitoring of nutrients in the Oualidia lagoon was carried out in four stations. The first results showed a considerable spatial and temporal variability of the physicochemical parameters. Indeed, nutrients of anthropogenic origin have been transported from agricultural areas to the Oualidia basin. However, these inputs were compensated by water exchanges with the adjacent open sea. These exchanges exerted a dynamic dilution effect and induced a short residence time in the water, thus limiting the enrichment and accumulation of nutrients for long periods. An overview of the previous studies, a comparison, and a hydrochemical characterization were performed to evaluate this work's results and give a general picture of the Moroccan Atlantic lagoons (i.e., Moulay Bousselham, Sidi Moussa, Oualidia, and Khnifiss)