The effects of chlorinated municipal sewage and temperature on the abundance of bacteria in the Sheep River, Alberta.

The intersite and temporal differences in the abundance of sessile and planktonic bacteria subjected to a chlorinated municipal sewage discharge and a thermal discharge were investigated in the Sheep River, Alberta, from January through December 1978. Significantly higher densities of both sessile and planktonic cells generally occurred within the chlorinated effluent plume. Higher numbers of sessile bacteria were also found below the thermal discharge, with maximum densities occurring in the late winter-early spring and minimum densities following mountain runoff. The higher numbers of sessile bacteria in the chlorinated plume was attributed to nutrient enrichment. These results indicate that chlorinated sewage effluent has no adverse effects on the abundance of sessile bacteria.