Background and objective: Damietta branch is one of the two main branches of the Nile River (Egypt), that often inhabited by many aquatic organisms, which affect and reflect its water characteristics. This study examine the relation between submerged macrophytes, their epiphytic microalgae and bacterial communities as well as the variations in their distribution and species composition with respect to season and location.
Materials and methods: Macrophytes, epiphytes and water samples were collected from 5 sites distributed along Damietta branch. Macrophytes, epiphytes and bacterial indicators of pollution were identified using standard methods.
Results: Three submerged macrophytes (Myriophyllum spicatum, Ceratophyllum demersum L. and Potamogeton crispus) and 191 epiphytic algal taxa dominated by 87 Bacillariophyta and 62 Chlorophyta were recorded with significance seasonal and spatial variations. Myriophyllum spicatum was the most frequent macrophyte (p = 100%) and represent about 100, 100, 97.4 and 64.9% kg DW m-2 of the total collected macrophytes biomass during autumn, winter, spring and summer respectively. The relation between some epiphytic algal species and specific macrophytes was evident and the high organic pollution tolerant algal species like, Melosira granulata, Nitzschia palea, Synedra ulna, Oscillatoria limosa, Microcystis aeruginosa were recorded. Results of bacteriological analysis revealed a significance difference in total viable bacterial counts developed on either 22 or 37°C, total coliform, fecal coliform, fecal streptococci and Escherichia coli attributed to the seasons and sites.
Conclusion: The results indicated different relations between macrophytes, epiphytes and bacteria, which is a useful biological tool for characterization of water quality in Damietta branch for different purposes.
Keywords: Biological characterization; bacteria; epiphytes; indicators of pollution; macrophytes.