Microbiological Studies of Shallow Marine Areas―II.Seasonal Change in Constituent Groups of Heterotrophic Bacterial Population in Respect of Polysaccharide Decomposition

摘要

The qualitative distribution of polysaccharide-decomposing groups among the heterotrophic bacterial population was compared seasonally through use of the samples of sea water and bottom mud collected from the Ariake Sea near Kashima City. The present studies dealt with seven kinds of polysaccharide in respect of decomposing ability. The results obtained are as follows. 1) The quantitative distribution by the pour plate counts was 1-7.8×102/ml in the sea water and 9-20×104/g in the sea mud, and relatively high counts were obtained from the samples of November. 2) The amino acid-requiring bacterial group seems to be most predominant. 3) Starch splitter was highly distributed, and pectinolytic or chitinoclastic bacteria were found in the mud throughout the year. The bacteria decomposing marine algae polysaccharide were distributed rather in the sea water than in the mud. 4) The constituent group among the heterotrophic bacteria, on the basis of the ability of polysaccharide decomposition, varied by the test season. The heterotrophic bacteria isolated from November's samples consisted of several groups having the ability to decompose various kinds of polysaccharide. The others were relatively simple constituent groups in polysaccharide decomposition.