Diatoms

According to Werner (1977) about 12000 bona fide species have been described. Diatoms probably contribute about 20-25% of the world's net primary production & in freshwater systems, diatoms yield from 20-50% of all the productivity of certain lakes (Siver 1977), thus
diatom productivity is as important as the boreal forest or the grasslands (Werner 1977).