Red Tide Observations along the Eastern Black Sea Coast of Turkey

To determine the occurrence of dominant phytoplanktonic species causing red tides along the eastern Black Sea (Trabzon) coast of Turkey, multiple samples were collected periodically between 1991 and 2001. Red tide events were observed only during the periods between February and July. Six phytoplanktonic species causing 5 red tide events detected were Diplopsalis lenticula, Euglena acusformis, Eutreptia lanowii, Pyramimonas orientalis, Scrippsiella trochoidea, and Gymnodinium sanguineum. Numeric density of species during the red tide events ranged between 0.97 x 106 and 356 x 106 cells l-1. During the red tides, the highest level of chlorophyll-a biomass ranged between 4.6 and 54.87 µg l-1. Effects of such ecological parameters as temperature, salinity, nitrite, nitrate, phosphate, and total Fe on the level of red tide, measured as the number of cells per litre, are also discussed.