Phytoplankton composition in izmir bay and parameters affect the composition

The aim of the present study is to elucidate similarities and/or dissimilarities of phytoplankton species by using Cluster and MDS (Multidimensional scaling) analysis and to show spatio-temporal differences and driving forces of environmental parameters by using PCA (Principal Components Analysis). Furthermore, some diversity indices; Simpson?s , Margalef?s , Fisher?s , Brillouin?s, Shannon?s, Pielou Evenness index based on phytoplankton community were used for describing the eutrophication state of the bay. During the study period, 133 phytoplankton species were determined belonging to the classes Bacillariophyceae, Dinophyceae, Dictyochophyceae, Euglenophyceae and Ebriidea. Besides phytoplankton, the class Ciliata as Protozoan was also examined. As environmental parameters; temperature, salinity, density, dissolved orthophosphate, nitrate, nitrite, ammonium, silicate, oxygen, organic carbon, total suspended solids, total phosphate, particulate phosphate and chlorophyll a were considered together with phytoplankton abundances. Although the phytoplankton abundance and nutrients were lower than these observed in the previous studies in Izmir bay, some nuisance, potential toxic and toxic phytoplankton species have been detected particularly in the harbour region. While the inner bay has been reported as eutrophic even called as hypereutrophic in the previous studies, the results of the present study has shown that there are strong evidences on ecological recovery particularly in the inner bay after the Centralised Metropolitan Sewage Treatment Plants have been activated since 2000. Keywords : Phytoplankton, diversity indices, PCA, MDS, Izmir Bay.