Abstract
The sporulation ratios in two dominant Bacillus groups were estimated both in the surface and deep sedimentary layers of a shallow pond.More than 60% of the members of A-group, represented by Bacillus megaterium, existed as vegetative cells both in the surface and deep layers.Although they have been regarded as strict aerobes, they seemed to have grown very slowly in the anaerobic condition.In contrast, More than 60% of the members of B-group, mainly consisting of Bacillus thuringiensis, existed as spores in the surface layer.
