Phytoplankton seasonality of a shallow turbid lake

Abstract

This work analyses the seasonality of phytoplankton (species richness, biovolume, diversity, abundance and dominance) associated with some physical, chemical and climatic variables of shallow turbid lake (Tatlι Lake, Turkey) between February 2000 and April 2001. Samples were collected monthly from the two stations from the surface (0–20 cm). Species richness and diversity (Shannon-Weaver, H’) index were calculated. Seasonal changes in phytoplankton community structure (i. e., the species present and their relative abundances) were evaluated with Nonmetric Multidimensional Scaling (NMDS) ordinations. Canonical Correspondence Analysis (CCA) was used to investigate the relationship between phytoplankton and physico-chemical parameters. A total of 144 species most of which belonged to the Bacillariophyta and Chlorophyta could be identified. Other taxonomic groups were Cyanoprokaryota, Euglenophyta, Pyrrophyta, Cryptophyta and Xanthophyta. The diatoms Cyclotella ocellata PANTOCSEK, Nitzschia palea (KUTZING) W. SMITH, Fragilaria ulna LANGE-BERTALOT and the green algae Ankistrodesmus falcatus (CORDA) RALFS show continuously high portions in the phytoplankton assemblage. High salinity and turbidity of the lake restricted the species number.