Seasonal Variations in Water Quality Parameters and Their Ecological Implications in the Western Harbor of Alexandria, Egypt

The Western Harbor of Alexandria, Egypt, is a critical coastal ecosystem facing significant environmental challenges from urbanization, industrialization, and pollution. This study investigated seasonal variations in key water quality parameters—temperature, salinity, pH, dissolved oxygen (DO), total dissolved solids (TDS), conductivity, and nutrient levels (PO₄, NO₂, and NO₃)—and their ecological implications. Water samples were collected seasonally from 19 stations across the harbor, and physicochemical parameters were analyzed to assess spatial and temporal trends. Results revealed pronounced seasonal patterns: sea surface temperature (SST) peaked in summer (average 29.12°C) and dropped to its lowest in winter (average 16.19°C). The highest values of salinity and TDS were recorded in summer due to increased evaporation, while nutrient concentrations varied by season, with phosphate (PO₄) peaking in summer and nitrate (NO₃) elevating in spring. These fluctuations are largely attributed to biological activity, agricultural runoff, and wastewater discharges. The harbor’s semi-enclosed nature exacerbates pollution, heightening risks of eutrophication, hypoxia, and heavy metal contamination. The ecological consequences of these seasonal changes include algal blooms, oxygen depletion, and habitat degradation, all of which threaten marine biodiversity and human health. Although this study did not directly assess biological impacts, the observed physicochemical changes highlight the urgent need for future research on marine community responses. Mitigation strategies such as reducing nutrient inputs, improving wastewater treatment, and implementing green infrastructure are essential for addressing these challenges. Regular monitoring and targeted interventions are recommended to ensure the sustainable management of the Western Harbor, safeguarding both its ecological health and economic significance. This research provides a foundation for future studies and policy actions aimed at mitigating pollution and enhancing the resilience of this vital coastal ecosystem.