The development of bacteria on the background of other components of the biocenosis of the River Nida (southern Poland) remaining under the influence of surface run-off from an intensively fertilized meadow

In the waters of the River Nida (southern Poland) the surface run-off from a riparian meadow (area 1 ha) intensively fertilized with ammonium nitrate (240 N kg ha-1 yr-1) caused a periodic, fairly small increase in the concentration of nitrate compounds, an increase in fertility (algal tests), and in bacteriological indices of the water, especially bottom sediments. Using Schrödinger’s coefficient, a greater energy expenditure was found per unit of bacterial biomass, pointing to a greater biodegradation of organic matter and a lower bioaccumulation in the water downriver of the intensively fertilized meadow. No significant changes were found, however, in communities of seston and sessile algae or in micro- and macrobenthos animals.