Phytoplankton Composition of Bulancak Stream, Interpretation of Water Quality Based on Indices and Functional Groups

This study aims to analyze the phytoplankton community of Bulancak Stream, determine the functional groups of dominant algae and reveal the ecological status of the stream with the help of indicator species. Phytoplankton samples were collected monthly from three stations between February 2018-January 2019 and environmental parameters were measured. Bacillariophyta is the dominant division, constituting 72% of the total abundance comprising 37 taxa. Cocconeis pediculus, Cymbella affinis and Ulnaria ulna species dominate at all stations. In the study, changes in the phytoplankton composition of Bulancak Stream were also examined with the most common diversity indices, Shannon Index, Simpson Index and Margalef Index and it was concluded that the species were equally distributed. The study identifies 15 functional phytoplankton groups that are commonly found in shallow and organically rich streams. To assess the water quality of Bulancak Stream, the Q(r) index developed for rivers was used in addition to the calculated WQI and the results were found to be consistent. According to both indices, the water quality at Station 1, which is close to the city center and empties into the sea was classified as moderate while the upstream stations were assessed as having good water quality.