PhysicalChemical Factors Affecting Diversity and Distribution of Bluegreen Algae in the Southern Caspian

The effect of physical and chemical factors on the species diversity, distribution and density of bluegreen algae was examined along the Nour shore of the Caspian Sea. Sampling was seasonal conducted during four sampling campaigns along four transects (A, B, C, D) each bearing three sampling sites (from 1 to 3) in February May, July and November 2014. As a result, 13 species of Cyanophyta division belonging to nine genera, were identified. The highest cyanophyte cell density was observed in summer, when 38 × 105 cells l1 was noted. However, the results of variance analysis illustrated that there is no significant difference between Shannon’s diversity index in different season (P 0.05 and F=0.521). The spatial distribution of bluegreen algae was nonuniform along the shore in the study area, but, along transects, the results proved that the highest density was usually at the first stations of each transect, except C. The most favorable conditions for bluegreen species growth were in late spring and summer, when the water temperature increased. In addition, the environmental variables such as salinity and nutrients, especially, phosphates affect the species diversity, distribution and density of bluegreen algae in the investigated area according to the Pearson correlation and linear regression.