Denitrification in the sediment of a eutrophic reservoir measured with the isotope pairing technique

Denitrification rates in the bottom sediment of the Rzeszów Reservoir (southeastern Poland) were measured using the isotope pairing technique. At the stations studied rates were reported in the range of about 26 to 610 μmol N₂ m^-2 h^-1, with the figures generally highest in summer. Simple and multiple regression analyses of relationships with selected abiotic factors gave rise to a model that revealed a statistically significant influence on rates of denitrification in the bottom sediment of the Rzeszów Reservoir due to concentrations of nitrate in overlying water, temperature, and the organic matter content in the sediment. The present study confirms that nitrate concentration in the overlying water is the main factor controlling sedimentary denitrification.