Microbial ecosystem and climate changes in the African lakes, the Case of Lake Nasser

Lake Nasser is the Egyptian central water bank. So, it is essential to secure its water from microbial pollution, where the monitoring of its microbial water quality is a must. Viruses play important roles in aquatic ecosystems. Through lysis of microbial cells, viruses help to drive nutrient cycling and speed up the release of nutrients into the environment, which microbial organisms can uptake. The sanitary quality of water includes total bacterial counts (TBCs) at 22°C and 37°C (incubation temperatures) as well as bacterial indicators of sewage bacteria; total coliforms, fecal coliforms, Escherichia coli, and fecal streptococci. On the other hand, fungi are a diverse group of microorganisms in the food web of freshwater ecosystems. Also, microbial communities involved in biogeochemical cycles are essential for environmental balance and water self-purification. In addition, these biogeochemical cycles significantly affect and are affected by global climate change where microbes act as either producers or consumers of greenhouse gases. The main goal of this chapter is to highlight the reservoir’s microbial ecology and biodiversity before water storage by the Grand Ethiopian Renaissance Dam (GERD) and draw some general conclusions about the likely evolution due to the possible changes after completing the filling of GERD.