Identification of Some Different Genuses of Diatoms and Their Relationships with Physic-Chemical Factors in Water of Haraz River

The diatom flora and their population were studied from March 2007 to February 2008 in Haraz River. Triplicate samples were gathered from 10 stations at monthly intervals: Temperature, pH, DO, EC were analyzed during this study. Samples were collected from rocks and sediments. For better observation cell walls and permanent mounts were prepared using Patrick and Reimer procedure and species were identified using Husted, Patrick & Reimer. In this study 33 kinds were identified, Navicula witht 21 species Gyrosigma with 4 species, Fragilaria with3 species, cocconeis and Achnanthes with 2 species, and Achnanthidium with1 species. Navicule radiosa, Navicula halophila and Navicula Viridula were dominant species in all period of study. The study revealed that, species diversity decreased downstream. This may be due to increased pollution with effects of diatom communitie's structure.