The distribution of phytoplankton in surf waters off Gopalpur (Lat. 19⁰6'N and Long. 84⁰56'E), east coast of India showed that the species composition and population density indicated well-marked seasonal variation. In total, 66 species of diatoms, 12 dinoflagellates, 3 blue-green and 2 green algae were encountered. The population density of phytoplankton ranged from 3.92 x l0⁴ to 7.23 x 10⁶ cells 1^-1. Higher population density and Chlorophyll a was observed in March when there was a bloom of Asterionella glarialis (=Asterionellopsis glacialis). The diversity indices showed considerable variations with minimum values in March in coincidence with the Asrerionella bloom.

Distribution, phytoplankton, surf waters, Orissa, east coast India