The study of Nodularia spumigena bloom event in the southern caspian sea

Abstract

Despite the increase in phytoplankton population in the Caspian Sea, there is few detail study regarding bloom of some species in the recent years. Previous studies have announced the bloom-forming Cyanophyta Nodularia spumigena Mertens to the Caspian Sea. In this study, we attempt to understand the bloom events that are involved Nodularia spumigena population and environmental parameters in the Iranian coastal water in 2009. The preliminary results suggested that Nodularia spumigena observed in the Caspian Sea in some seasons at different depths but bloom formation starting from middle of summer and reach a maximum in the early of autumn at the surface. Result of this study also showed that phytoplankton assemblage comprised of 46 species after bloom. Bacillariophyta had the highest number of species (17) follow by Pyrrophyta (14), Cyanophyta and Chlorophyta (6) and Euglenophyta (3). But, phytoplankton species of bloom sample is classified in three groups: Cyanophyta, Pyrrophyta and Bacillariophyta which Cyanophyta dominated over the other groups of algae and formed more than 98% and 96% of phytoplankton abundance and biomass, respectively. As of now, the pattern of dominant and frequent species in the Caspian Sea indicated that the health of the water body and aquatic organisms are at risk. © 2011, ALÖKI Kft., Budapest, Hungary.