Mineralization Activity and Bacterial Population in the Hiuchi-nada

The purpose of the present study was to contribute to background knowledge of the relation between mineralization and bacterial population in the Hiuchi-nada. To measure mineralization activity, samples of sea water and bottom sediments were incubated in a medium containing U-14C-glucose and the radioactive carbon dioxide pro-duced was estimated. In the surface waters, mineralization values ranged from 25 to 1296mg-cm3. day, and heterotrophic bacterial populations ranged from 1.1×104 to 2.4×107 cells/ml. Higher values of mineralization and bacterial population were more common in the inshore waters than areas remote from land influences. Comparison of several stations suggested that some relation exists between mineralization activities and heterotrophic bacterial numbers. In the bottom sediments mineralization values ranged from 69 to 204μg-C/100g. day, and heterotrophic bacterial populations ranged from 1.3×105 to 2.4×107 cells/g. The relationship between mineralization and bacterial population in this case is obscure. Mineralization activities per unit bacterial cell ranged from 0.27 to 96.88×10-12mg-C/hour in sea water and from 1.82 to 116.56×10-12mg-C/hour, in bottom sediments.