Biodiversity of zoosporic fungi in polluted water drainages across Niles’Delta region, Lower Egipt

Abstract

Thirty-four identified in addition to five unidentified species appertaining to ten genera of zoosporic fungi were identified and isolated from eighty four polluted water samples, which were randomly collected from different polluted sites of the water drainages along the Niles Delta in Lower Egypt. Baiting sesame seeds culture technique was employed at 20±2º C for the recovery of zoosporic fungi. The genera; Pythium and Saprolegnia (8 and 7 zoosporic fungal species, respectively) showed the broadest spectra of species diversity whereas Aqualinderella was only represented by one species (A. fermentans). Saprolegnia delica and Dictyuchus carpophorus (the greatest fungal populations) were the most dominant isolated zoosporic fungal species where they were highly occurred especially at the hyper-polluted waters with the heavy metals. These two species could be considered as indicators for the response of the structure and function of microbial communities for water pollution. Several zoosporic fungal species were rarely encountered. Both Aqualinderella fermentans and Pythium rostratum were recovered in moderate frequency of occurrence. Water samples which had high concentrations in heavy metals were the poorest in the species diversity of zoosporic fungi. Despite that, fungal species belonging to the family Saprolegniaceae flourished in hyper polluted water samples whilst those belonging to the family Pythiaceae predominated in more diluted water samples. Also, the prevalent species; S. delica and D. carpophorus were not affected by heavy metals concentrations being as indicators for water pollution with the heavy metals. pH values of the polluted water samples had no influence on the occurrence of zoosporic fungi. Water samples characterized by high organic matter content and low total soluble salts were the richest in zoosporic fungal species.