Pollution load and dynamics of phytoplankton communities in relation to environment variables in Lake Babogay, Ethiopia

The objective of this study was to investigate the water quality of Lake Babogaya in Ethiopia. Water samples were collected from six different sites, and analyzed for total coliform (TC), fecal coliforms (FC), and Escherichia coli (E.coli) content. Additionally, potential of hydrogen (pH), dissolved oxygen (DO), total dissolved solids (TDS), electrical conductivity (EC), and Secchi depth were measured. Nutrients and heavy metals were determined using standard methods. The abundance of phytoplankton was estimated by calculating the biovolume of the species. The results indicated that pH, TDS, DO, and turbidity ranged from 8.78 + 0.31 to 9.52 + 0.04, 129 + 4 to 419 + 3 ppm, 5.50 to 7.25 mg/l, and 0.96 to 17.29 NTU, respectively. TC bacteria exceeded the World Health Organization (WHO) standards at all sites, while FC levels exceeded in most samples. Cadmium and chromium were low in both seasons, whereas lead in the dry season exceeded the WHO limits. The levels of iron were high across all sites in the dry season and low in most sites in the wet season. Five major taxonomic phytoplankton groups were identified, comprising a total of 31 species with highest richness of green algae, blue-green algae, and diatoms species.