Abstract
A statistical study on the morphological variations of the dinoflagellate species Ceratium egyptiacum Halim was carried out in three distinct natural environments: The Red Sea, the Bitter Lake (Suez Canal), and the Mediterranean waters at Port Said, Egypt. Significant seasonal and regional variations were found in the parameters studied (length of the cell, transdiameter, length of the apical and right antapical horns). These variations are mostly attributable to variations in both the temperature and salinity of the environment. On the whole, it was found that high temperature tends to produce longer horns and smaller thecae, while low temperature produces larger cells with shorter horns; high salinity tends to intensify these effects. The right antapical horn is the most labile horn, and the transdiameter of the cell is the most stable parameter. It is suggested that these variations are directly related to flotation. The effect of the Bitter Lake as a unique natural environment (salinity 47‰) on plankton organisms has been evaluated; it is a function of time. The systematic consequences of the structural variations have been discussed; they are probably not genetic, and the resulting types are mere ecotypes of no immediate systematic consequence.
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Communicated by T. R. Parsons, Vancouver
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Dowidar, N.M. Morphological variations in Ceratium egyptiacum in different natural habitats. Marine Biology 16, 138–149 (1972). https://doi.org/10.1007/BF00347952
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DOI: https://doi.org/10.1007/BF00347952