Identification of culturable microalgae diversity in the River Nile in Egypt using enrichment media

Abstract

This study aimed to morphologically identify the highest possible microalgae biodiversity in a sample collected from the River Nile using the culture-based method. Water samples were cultured on the two commonly used media BG-11 and BBM media to obtain a broad spectrum of microalgae biodiversity. Likewise, the effects of nutrients concentration and vitamin supplements to BG-11 and BBM for supporting the maximum diversity of culturable microalgae were tested. Cell counts and morphology-based identification were conducted to evaluate the population diversity. A total of 35 species have been identified using the two media combined. The standard BG-11 and BBM media enriched 25 and 27 species, respectively, while the reduced nutrient concentration of BG-11 and BBM had a species richness of 19 and 24, respectively. The vitamin-enriched media each sustained BG-11+Vit (23) and BBM+Vit (20). We found that some algae species were uniquely identified on the reduced nutrient concentration or vitamin-enriched media. The results of this study report the current algae diversity in the Nile demonstrating that the usage of single-culture media for algal enrichment would result in underestimating the species richness. The diversity identified can be used as a reference for continuos monitoring of the River Nile microalgae diversity in Cairo.