Report blue-green algae from the southern coast of the Caspian Sea (City of Noor)

The blue green algae as photosynthetic organisms have a main effect on life and productivity of the aquatic ecosystems. Intensive and longtime studies on identification, distribution, and diversity of Cyanophyta have to be a crucial task in the Caspian Sea. Four transects were determined parallel to the Sabzehrud River, the Lavij River, the Noor River, and the Faculty of Marine Sciences of Tarbiat Modares University from 2014 to 2015. Samples were seasonally collected from three stations in each transect by a plankton net with a mesh size of 55 and the Ruthner's bathometer. Standard hydrobiological and phycology approaches were used for identification and counting abundance of Cyanophyta. The most number of Cyanophyta was observed 1.06 × 106 cells per liter at the station of A1 during summer. Genera such as Chroococcus, Gloeocapsa, Merismopedia, Microcystis belonged to unicellular taxa and Anabaena, Anabaenopsis, Nostoc, Oscillatoria, Phormidium were identified as multicellular genera. At the most stations, Anabaenopsis nadsonii was found as the most encountered species. Overall, Cyanophyta abundance was significantly different among stations in all investigated seasons. The blue green species also did not have same frequency distribution inside of the each transect (Test Chi-Square, P <0.05).