The first report of non-native phytoplankton, Dinophysis acuminata from the Anzali shores, Caspian Sea

This study focused on the changes in the phytoplankton community of the southern Caspian Sea with an emphasis on the climate change effect. The present study was conducted in the Anzali coast at 10 m depth in May 2023. A total of 33 genera and species were identified from the phyla of Ochrophyta, Chlorophyta, Cyanobacteria, and Myzozoa. The total phytoplankton abundance was measured 135,000±53.000 cells/l. Among the phytoplankton taxa, Ochrophyta had the highest abundance about 99,900±63,000 cells/l. These findings showed an increase in the abundance of phytoplankton in 2023 was 7-fold more than in 2008. The non-native phytoplankton, Dinophysis acuminata from Myzozoa phylum was recorded in the Caspian Sea for the first time. The abundance of D. acuminate was 1620 ± 730 cells/l and the size of the phytoplankton was 30 µm. Probably increase in salinity (13 psu) and increase in sea surface temperature (Climate change) of the Caspian Sea caused the appearance of D. acuminate species.