Critical Changes in Composition of Diatoms Community in East Hammar Marsh, Southern Iraq

Diatoms have dominance in most Iraqi aquatic environments, such as in the Al-Hammar Marsh in southern Iraq, thus they are reflecting the quality of water and environmental factors prevailing in their places of residence. The East Hammar marsh in southern Iraq has experienced substantial environmental changes especially the high temperature and salinity during the last decades. Water quality has deteriorated which has impacted the living species that reside there, the most important of which are diatoms. During August 2018 to April 2019, qualitative and quantitative characteristics of the planktonic and epiphytic diatoms were studied in the East Hammar marsh at three sites, Al-Sadda, Al-Salal, and Al-Burka. During this investigation, 69 taxa belonging to 37 genera were identified and documented. Diatom assemblages contained 30% of brackish water forms, 21 % of marine-brackish water species, 16 % of fresh species, 10% of marine water species, and the remaining 23% had varied ecological preferences ranging from fresh to marine forms. Marine-brackish water species predominate during the summer, whereas freshwater species predominate during the winter.