Differences in the characteristics of the bacterial community in the epilithon and river water as demonstrated by plate count and staining methods

Summary

A study was made on seasonal fluctuations in the bacterial density in the water column and benthic epilithon at Koremasa of the River Tamagawa in Tokyo, Japan. Principal component analysis of water quality and environmental factors showed that the first principal component was composed of DOC, PO₄-P, TDP, NH₄-N, NO₃-N and chlorophyll a in the epilithon. The bacterial densities in the water and epilithon were determined by the acridine orange direct count (AODC), INT-formazan count (INT) and agar plate method. Change in the bacterial density estimated by plate count in the epilithon was highly correlated with the first principal component. The percentage of the INT/AODC was higher in the epilithic microbial community than in the one in the water. However, bacterial density in the river water was controlled by the different factors investigated in this study.