Biological assessment is considered a useful tool for assessing the ecological status of the aquatic ecosystems. Therefore, the goal of the present study was to use phytoplankton and macroinvertebrates as biological tools for ecological assessment of the River Nile around Gizert El-Warrak. A total of 33 phytoplankton species identified in the studied stations; these include 16 species of Chlorophyta, 5 species of Cyanophyta and 12 species of Bacillariophyta. All investigated stations characterized by high organic pollution according to Palmer's index. Trophic state index showed a hyper-eutrophic status in stations S1, S2, S4, S6 and S8 and an eutrophic status in stations S3, S5 and S7.Gastropoda and Oligochaeta were the most dominant of macroinvertebrates taxa recorded 50.8 and 24.6%, respectively. Diversity Index (H') ranged (1.14 - 2) which indicated that the structure of macroinvertebrates habitat was poor. Also, Evenness Index (J) ranged (0.016 - 0.043) which indicated that individuals were not distributed equally. The values of biotic index depending on macroinvertebrates categories showed that the River Niles water quality is fairly poor with significant organic pollution.\n\nSummary statementBioassessment based on non-taxonomic measurements of algae and biotic indices of macroinvertebrates may be considered as vital methods that reflect disturbances in aquatic systems for both short-term and long-term.
