Seasonal succession of the phytoplankton community and evaluation of water quality using trophic diatom index in a stream

Abstract

Phytoplankton species composition, seasonal variation and the factors effecting the variation were studied in this study one-year period, from June 2010 to May 2011. Water samples were collected monthly from four stations. Algae of the stream was determined by the enumaration and identification of the collected samples. A total of 53 phytoplankton taxa were determined, consisting of Bacillariophyta (79%), Chlorophyta (9%), Cyanobacteria (6%), Euglenozoa (4%) and Cryptophyta (2%). Bacillariophyta dominated mostly in species variety. Diatoms are commonly used as biloindicator organisms for evaluating especially freshwater quality. Trophic diaton index (TDI) provides information about trophic levels of the aquatic ecosystem. The water quality of Buyuk Gure Stream in terms of trophic levels was determined according to these 42 diatom taxa by calculating TDI. It was determined that Buyuk Gure Stream has eutrophic state, caused by organic pollution, according to TDI. Ankistrodesmus falcatus was dominant species in June. Total organism numbers reached its highest level in July during the study period. The number of species and diversity of phytoplankton showed seasonal variation, being low in rainy season. Rainfall, light and temperature are expected to be the major factors which influence phytoplankton succession and dominance. © 2016, Scibulcom Ltd. All rights reserved.