Persistence and Differential Survival of Fecal Indicator Bacteria in Boukourdane Waters

Fecal bacteria are indicator organisms used worldwide to monitor water quality. These bacteria are used in microbial source tracking (MST) studies. Ideally, all strains of a given indicator organism (IO) would experience equal persistence (maintenance of culturable populations) in water; however, some strains may have comparatively extended persistence outside the host, while others may persist very poorly in environmental waters. In our study, we recorded the highest density of fecal bacteria in winter, and the lowest in spring and summer. They are also more in deep regions rather than on the surface, which might be due to the Inhibitory effects of solar radiation, which has been shown to influence the survival of these organisms. The concentrations of fecal bacteria were not only a result of temporal or spatial variability in their sources, but also the fact that various bacteria have different lifespans that vary according to environmental factors, such as temperature, pH, concentration in nutrients, and solar radiation which is responsible for 99% of the mortality of fecal coliforms on the surface.