Ecological distribution of harmful epiphytic Oscillatoriales in Alexandria coast, Egypt, with special reference to DNA identification

Objective: To identify the potentially harmful epiphytic Oscillatoriales species and follow up their distribution along Alexandria coast. Methods: Samples were collected bimonthly from April 2009 to February 2010 at three sites along Alexandria coast. Both morphological and molecular analyses were used for identifying the dominant species. Results: Five species belonging to two families were identified; Oscillatoria acutissima, Oscillatoria nigroviridis, Oscillatoria sp., Lyngbya majuscule and Phormidium formosum. Their cell density ranged from 103 to 126×103 filament g-1 fresh weight macroalgae. The morphological study of the dominant species, Oscillatoria sp. (Oscillatoria sp. W1) showed much similarity with Planktothrix agardhii with no heterocysts and akinetes, while molecular ananlysis (16S rDNA) clustered the species in the same group with Anabaena sp. Conclusions: The 16S rDNA genes are not suitable for identifying Oscillatoriales during the present study and another molecular method should be used instead