The Caspian Sea ecosystem, with its high level of endemic taxa has suffered from anthropogenic pollution, changes in the quantity of nutrients, and the effects of invasive species since the 1980s. The change in phytoplankton community was undertaken in the southwestern Caspian Sea between 1996 and 2010. An increase in phytoplankton abundance was observed after 2000, and has continued until 2010. Except in 2001 and 2002 diatoms predominated throughout the study. A decrease in silicate levels and an increase in water temperature, salinity and stratification were the main factors causing a bloom...