A notable relation was observed between diatom
growth and silica concentrations in the present study.
Silica concentrations decreased gradually during the
vernal growth of diatoms and were recorded at their
lowest when the vernal maximum ended. In fact, silica
concentrations decreased during such growth periods and
increased whilst individual numbers of diatoms were
decreasing. This finding is in harmony with that of
Pearsall (1930), who suggested that the fall in silica
concentrations coincides with the diatom maxima.
The lake appeared to have moderately hard water.
Calcium had no strong effects on the growth of any algal
group since concentrations of calcium varied only
between 38 and 48 mg l-1 during the study. A similar
situation was also observed for magnesium since
variations in its concentrations were negligible.