A floristic research on the algae of Bogacik stream (Giresun)

Water samples were taken from four selected station monthly between January 2017 and December 2017 to analyze seasonal changes at phytoplankton flora of Boğacık Stream. Counting and identifications of phytoplankton species were done by examining the samples. Also, chlorophyll- a, physical and chemical analyses of the water samples were defined. 65 taxa were detected in the phytoplankton of Boğacık Stream. They were Bacillariophyta (51), Chlorophyta (6), Charophyta (4), Cyanophyta (2) and Euglenophyta (1). The members of Bacillariophyta division was dominant in the aspect of the taxa number and density of species in the four selected stations. Botryococcus braunii, Cocconeis neodiminuta and Diatoma vulgaris showed dominance throughout the research at all stations. The lowest and highest total amount of organism was recorded in December and March in the seasonal changes of the phytoplankton. Chlorophyll- a concentration was changed between 1,04 mg/m3 and 20,32 mg/m3 on the surface waters of the research area. When that changes were analyzed, repeated changes were deserved periodically according to months. Additionally cluster and Shannon and Weaver diversity and evenness indexes were applied to the phytoplankton flora of Boğacık Stream.