Temporal variations of phytoplanktonic diatom and dinoflagellate communities and some physicochemical parameters in Akyatan lagoon (Karatas, Adana)

Lagoon areas are sensitive ecosystems that are highly affected by the physical and chemical environmental conditions of the surrounding area. The Akyatan Lagoon lies within the boundaries of the Karataş district of Adana Province and is a part of Ramsar protected area. In this study, temporal changes of diatom and dinoflagellate communities and some physicochemical environmental parameters were investigated in Akyatan Lagoon. In this context, water samples were collected monthly from 6 selected stations within the lagoon during April 2015-March 2016 period. Nutrient values such as nitrite + nitrate, ammonium, phosphate and silicate showed considerable fluctuations throughout the year in the lagoon, and due to the drainage canal and other terrestrial inputs, have reached quite high levels. Chlorophyll-a values varied widely from time to time and ranged from 0.40 to 52.66 µgl-1 throughout the study. When the seasonal distribution of diatom and dinoflagellate abundances in the lagoon was examined, the diatom abundances varied between 0.04x105 cells l-1 and 21.23x105 cells l-1. The lowest diatom abundance was observed in January 2016 where the highest diatom abundance was observed in October 2015. The dinoflagellate abundance in the lagoon varied between 0,28x105 cell l-1 and 80,55x105 cell l-1. The lowest dinoflagellate abundance was detected in January 2016 and the highest abundance was detected in April 2015. The dinoflagellates abundance was more dominant than the diatoms in the Akyatan Lagoon. It has been determined that the nutrient levels in the Lagoon lake reach very high levels due to drainage canals and other inputs. It was deduced that the high levels of nutrients in the environment is influential on diatom and dinoflagellate abundance to reach very high levels.