fa <p><span style="color:black;"><span style="font-family:times new roman,serif;"><span style="font-size:12.0pt;">Due to the recent destructive </span></span></span><span style="font-family:times new roman,serif;"><span style="font-size:12.0pt;">pressures on the Caspian environment, an effect on phytoplankton communities is expected in different aspects such as cell size and form. This paper aims to survey the size and form in the dominant phytoplankton species in the years of 1996, 2001, 2006, 2009, 2011 and 2012 in the Iranian coast of the Caspian Sea. Results of current study showed that the dominant species and along with it their sizes and forms remained quite similar in the fall of different years, but the greatest shift in size and form were observed during spring, summer and winter. It </span></span><span style="font-family:times new roman,serif;"><span style="font-size:12.0pt;">is suggested that<span style="color:black;"> these changes reflect an ecological disturbance and instability in the</span></span></span> <span style="color:black;"><span style="font-family:times new roman,serif;"><span style="font-size:12.0pt;">Caspian environment</span></span></span></p> Phytoplankton, Dominant Species, Size, Form, Caspian Sea, Iran 522 536 http://jifro.ir/browse.php?a_code=A-10-714-7&slc_lang=fa&sid=1 A. Makhlough 100319475328460021303 100319475328460021303 No H. Hassan Nasrollahzadeh Saravi hnsaravi@gmail.com 100319475328460021304 100319475328460021304 Yes F. Eslami 100319475328460021305 100319475328460021305 No S.A.G. Leroy 100319475328460021306 100319475328460021306 No