Vertical distribution of Cyanobacteria of the marine rocky supralittoral of the cape Kilse-Burun (Meganom peninsula, the Black Sea)

Abstract

The vertical (altitudes at 0.1; 0.3; 0.6; 0.9 and 1.2 m above mean sea level - MSL) distribution of Cyanobacteria in the supralittoral zone of the Cape Kilse-Burun (Meganom Peninsula) was characterized. A total of 20 species of Cyanobacteria have been recorded; their number at various altitudes varied from 6 to 9 (minimal at 0.9 m above MSL). As for the systematic composition, species of the Oscillatoriophycidae subclass were found on the entire range of altitudes. The high contribution of representatives of the Synechococcophycidae subclass was noted at altitudes of 0.3 and 0.6 m MSL. The orders Chroococcales and Oscillatoriales were dominant at 0.3 m MSL; and the order Nostocales - at 0.1 m MSL. Among the families, Rivulariaceae family was observed at all altitudes, with a predominance at 0.1 m and 1.2 m MSL. The genera Gloeocapsa , Aphanocapsa and Leptolyngbya (with a low contribution) have been recorded at almost all altitudes. Only the genus Calothrix at altitudes of 0.1 and 1.2 m MSL represented 25.0% and 37.5%, respectively. According to the substrate confinement, the noted microphytes belonged to the attached ones; benthic mesosaprobiont marine species predominated in the entire surveyed range of altitudes. Brackish-marine (except 0.9 m above sea level) and freshwater-brackish (except 0.1 m above sea level) species were noted almost all over the range, while only one freshwater species was recorded at 0.1 m MSL. Species with cosmopolitan and boreal-tropical distribution predominated at all altitudes. The share of the latter was the highest at 0.1 m MSL, which is probably due to the relatively low temperature of the substrate under conditions of maximum surf irrigation. The features of the vertical distribution of Cyanobacteria emphasize the specificity of the environmental conditions of the supralittoral biotope.