Distribution, phytoplankton abundance and impact of Eichhornia crassipes in the Eynak Wetland, Guilan state-Iran

This study focused on identification, phytoplankton structure and abundance in the Eynak wetland in 2017. Based on the condition of wetland, the samples were collected at 4 stations in the water body. This study identified 30 phytoplankton taxa comprised of Diatoms (9 genus), Chlorophyta (7 genus), Cyanophyta (9 genus), Dinoflagellata (2 genus) and Euglenophyta (3 genus) in the lake. The finding showed, the Cyanophyta abundance dominated (94 %) with average of 31300000 ± 21400000 cells.l-1 in the Eynak wetland. The Cyanophyta Oscillatoria sp. was toxin which had been the highest abundance almost 28200 000 cells.l-1in the wetland. The lowest abundance was comprised of Euglenophyta almost 303000±48000 cells.l-1 during the study. Furthermore, there were the Euglenophyta Lepocinlis sp. and Euglena sp. in the wetland, which are water polluted index. The finding showed, decline of phytoplankton abundance at the Eichhornia crassipes stations and the abundance received from almost 1700000 to 5800 0000 cells.l-1 at the stations of without E. crassipes. The increase in E. crassipes is reason of photosynthesis decries and phytoplankton abundance in the wetland which no control of E. crassipes, would be more negative impact in the Eynak wetland. The decrease of nutrients level and biological, chemical and mechanical control on E. crassipes are important for resuscitation of the ecosystem.