| Abstract: | Samples of phytoplankton were taken from the Euphrat and Tigris Estuary (Shatt al-Arab) in April 1974 and investigated by means of the inverted microscope. Among 226 species identified in the samples 95 were of marine origin. The share of diatoms in the total numbers of cells from all stations amounted to 68%. The abundance of planktonic green algae amounted to 19%, of the blue greens to 13%. The number of marine species continuously increased in the longitudinal axis of the 139 km section considered. The data of the phytoplankton were compared with the gradation of some environmental variables (temperature, transparency, dissolved oxygen, chloride). Regular longitudinal or vertical differences of these parameters were not observed. |
