Studies on microbial population in coastal waters - I : Distribution of nitrogen-cycle bacteria in the Kumano Nada and its adjacent areas

The occurrence and distribution of nitrogen-cycle bacteria in the Kumano Nada and its adjacent areas were studied during 1981-1983. Heterotrophic bacteria in the water usually occurred at the level of 100-104/ml.The distribution of heterotrophic bacteria was uneven horizontally as well as vertically.The number of nitrate-reducing bacteria was in the order of 10-1-103 cells/ml, while denitrifying bacteria were in the range from 10-1 to 102cells/ml or sometimes lower than the value. The occurrence of nitrogen-fixing bacteria and nitrifying bacteria in the surface water was also very few ranging from 100 to 102 cells/l