天美传媒

Abstract

Because of changing the condition of Southern Caspian Sea, in After Mnemiopsis leidyi arrival (during 2006-2007), some Cyanobacteria species like Nodularia spumigena displacing in Southern Caspian Sea that can harm the overall health of the Caspian Sea. All samples were taken during 1995-96 and 2006-2007 in 6 transects such as Lisar, Anzali, Sefidroud, Noushahr, Babolsar and Amirabad, respectively. The Cyanobacteria compositions were changed significantly with seasons (P<0.05). In comparison after Mnemiopsis leidyi arrival, Cyanobacteria species were increased. Totally 33 species of Cyanobacteria identified. During this study, Cyabobacteria community in the Caspian Sea changed in different years and the maximum cell abundance and biomass observed in summer and Shannon-Weaver diversity index changed in this study. During 2006-2007 (after M. leidyi arrival), the Cyanobacteria are shown significant changes in diversity at different seasons (P<0.05). According to statistical analysis, there was a significant change in seasonal cycle of Cyanobacteria concentration. Because decreasing siliconate phytoplankton in the summer, Nodularia spumigena, of Cyanobacteria, bloomed in 2005.

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