Species composition and abundance of Diatoms in the lower Ferlo valley were studied after ten years of its reflooding. A qualitative sampling of diatom from upstream waters toward the downstream side was carried out in five stations using a Phytoplankton net of 30μm mesh size. A total of 71 species of diatoms belonging to 25 genera were identified in this study. The species richness decreased with increasing level of salinity from upstream toward the downstream side. The highest species richness and abundance were observed in upstream stations. The most abundant species were Aulacoseira granulata, Nitzschia compressa, Nitzschia desertorum, Navicula halophila, Surirella robusta, Gomphonema truncatum, Fragilaria ulna and Cocconeis placentula. While the most abundant species in the upstream stations was Aulacoseira granulata, Navicula halophila dominated in the downstream side stations with higher salinity values. Thus, the salinity concentration seems to play a major role in the diatom species distribution in lower Ferlo valley.
