Activity and abundance of bacterioplankton in three diverse lowland water courses

Abstract

AbstractThe hypothesis that the activity and abundance of bacterioplankton were similar in two low‐level fenland water courses, but were different from those in a high‐level main river, was rejected. Mean values of Vmax for glucose mineralization, Vmax per bacterium, abundance of free‐living and total directly counted bacteria, abundance of colony‐forming units and percentage of culturable bacteria were similar in the low‐level Beverley and Barmston Drain and in the River Hull, but were less in the low‐level Holderness Drain. The less favourable regime in the Holderness Drain was related to intermittently acid conditions. Temporal variation by bacterioplankton in all three water courses was, however, also related to environmental variables other than pH, notably temperature, chlorophyll, biochemical oxygen demand, current velocity, total suspended solids and particulate organic matter. The activity and abundance of bacterioplankton appeared to have increased in the River Hull between 1975–1976 and 1992–1994.