Seasonal distribution of phytoplankton community in a subtropical estuary of the south-eastern coast of Bangladesh

Abstract

Phytoplankton are the basic component of the aquatic food chain. To date phytoplankton communities from the coastal waters of Bangladesh have received only little scientific attention. Consequently, the abundance and community composition of phytoplankton and their relationship with some abiotic factors were studied during December 2014 to August 2015 in the Reju Khal estuary of the south-eastern coast of Bangladesh. Marked seasonal differences were observed for all of the measured abiotic factors. The density of the phytoplankton cells ranged between 9408 and 21,964 cells L−1 and had significant differences among seasons. Over all seasonal samples, 27 genera were identified of which Biddulphia was found to be the most contributory one (13.6%) followed by Coscino discus (7.9%) and Nostoc (7.8%). Marked seasonal differences in the community structure of phytoplankton were confirmed by the multivariate analyses. Further, phytoplankton populations had strong positive correlations with pH, salinity, total dissolve solids, and Secchi depth.