Morphological analysis
We identified by light microscopy a total of 40 genera and 98 species across all study samples. The number of species and genera per sample ranged between 5-21 and 4-17 respectively, with an average of 14 and 10 respectively. Moreover, 5 species were identified in most samples -Achnanthidium minutissimum (Kützing) Czarnecki, Eunotia bilunaris (Ehrenberg) Schaarschmidt, Fragilaria tenera (W.Smith) Lange-Bertalot, Ulnaria acus (Kützing) Aboal, andGomphonema exilissimum (Grun.) Lange-Bertalot & Reichardt-.