Aquatic Ecosystems Facing Pollution: Impacts and Biosurveillance

Aquatic ecosystems are essential for biodiversity, human well-being, and the sustainable use of water resources. However, urbanization, agriculture, industry, domestic activities, and maritime pressures are increasingly affecting freshwater and marine environments. This work provides an integrated overview of aquatic pollution, its main sources, its effects on aquatic organisms and human health, and the methods used to assess environmental quality. It describes the structure and functioning of aquatic ecosystems and examines major pollution sources, with particular attention to the Algerian context. Key physicochemical parameters used to assess water quality are presented, together with the main biological effects of pollutants, including toxicity, bioaccumulation, biomagnification, and disturbances in aquatic organisms. Particular attention is given to aquatic biomonitoring through bioindicators, sentinel organisms, biomarkers, and modern monitoring approaches for detecting biological responses to environmental stress.