Spatial, Seasonal Variation and Biodiversity in Phytoplankton communities in al-Diwaniyah river - Iraq Falih-Al-Khalidi Ahmed Mahmoud*, Al-Asady Raid Kadhim Abed** *Ministry of Environment, Environment Directorate of Al-Qadisiyah, Iraq **University of Al-Qadisiyah, College of Education/Biology Department, Iraq Online published on 27 August, 2019. Abstract Identification and diversity of Phytoplanktons was studied in five sites in the River of Al-Diwaniyah – Iraq during the period from January 2018 to December 2018. A total of 224 taxa belonging to 66 genera were diagnosed in all study sites. Atotal of 224 taxa were identified in all stations of study and dominated by diatoms (120 taxa).pennales were represented by 107 species only, and 13 species belong to Centrales diatoms followed by green algae recorded 54 species and then blue green 42 species. Euglenophyta recorded 6 species, while the Pyrrophyceae was one species. It was also notice that few genera were dominated namely, Oscilltoria spp., Scendesmes spp., Cocconies placentula, Cyclotella meneghiniana, Melosira ambigua, Navicula cincta, Synedra acus, during the period of the study in all stites. The highest density of phytoplankton was recorded during the month of April, at 2918.4 × 310 cells/liter, and the lowest density at site (3) during the month of January was 278.3 × 310 cells/liter. Shannon -Weiner for Diversity showed the highest value in Site (1) at 3.66 during April and the lowest value on site (3) in February and reached 1.19. Top Keywords Phytoplankton, Identification, diversity, Diwaniyah river, Shannon –Weiner. Top |