The effect of Mnemiopsis leidyi on Cyanobacteria in different years and seasons in Southern Caspian Sea

The purpose of this work was to study phytoplankton of different seasons.For maturing of phytoplankton Factors, choose 6 line Lisar, Anzaly, Sefidrood, Nooshahr,Babolsar and Amirabad that every line have 4 stations(A, B, C, D) and water for analysis have taken from different deeps ( 0,5,10,20,50,100) meter in southern ofCaspian sea and then transferred to laboratory of Caspian sea ecological institute. In this study, cell abundance and biomass of Cyanobacteria in different seasons weresignificant different. The dominant cell abundance was recorded in spring while theminimum were in winter. Shannon-Weaver diversity index (Shannon et al., 1963) of Cyanobacteria species ranges from 0.00 to 0.696 that belong to Oscillatoria tenuis.Ecological and environmental alterations may trigger changes in the phytoplankton species number, abundance and biomass. Then, since phytoplankton depends uponcertain conditions for growth, they are a good indicator of change in their environment. For these reasons, and because they also exert a global-scale influenceon climate, phytoplankton are of primary interest to oceanographers and Earth scientists around the world. Algae and cyanobacteria produce the bulk of primary production in seas. 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.

کلیدواژه ها:

Pollution ، Caspian Sea ، Cyanobacteria