M. Zarghami F. Nazarhaghighi M. M. Sohrabi Mollayousefi Young Researchers and Elite Club, Islamshahr Branch, Islamic Azad University, Islamshahr, Iran Young Researchers and Elite Club, Rasht Branch, Islamic Azad University, Rasht, Iran Department of Geology, Islamshahr Branch, Islamic Azad University, Islamshahr, Iran Proceedings of the International Academy of Ecology and Environmental Sciences ISSN 2220-8860 http://www.iaees.org/publications/journals/piaees/online-version.asp 2019 9 3 73 88 International Academy of Ecology and Environmental Sciences Hong Kong 12 March 2019 20 April 2019 1 September 2019 worms Caspian Sea environmental factors Meiofauna The Caspian Sea is a large lake renowned for its diverse aquatic fauna. This study investigates recent meiofauna worms from sediment samples collected during spring, summer, autumn and winter 2012 from 12 stations (ranging in depths 5, 10, 20 and 50 meters) in the Southern Caspian Sea from Bandar Amirabad to Ramsar. The benthic environmental factors including temperature, dissolved oxygen, salinity and pH were measured by CTD during the sampling time. Associated factors includes: grain size, Total phosphate, Total nitrate, total organic matter and calcium carbonate concentration were also measured. In this research three classes of worms (Nematodes, Annelida and Platyhelminthes) were identified. The result of One Way ANOVA showed that density of Worms has been different significant with depth and stations (P less than 0.05). Result of Pearson correlation showed that between density of worms and %Silt and Clay, %TOM, depth and %CaCO3 had been negative correlation. The highest density being observed in autumn, most density of worms was observed in Babolsarstations (B1) (759.78 ind/0.1m2). That showed a good situation for living there. Urbanization had important role in this area that increased abundance of meiofauna tolerance worms. http://www.iaees.org/publications/journals/piaees/articles/2019-9(3)/effect-of-urban-pollutants-on-distribution-of-meiofauna-worms.pdf