Estimation of denitrification rate in diversified bottom sediments of the Sulejow Reservoir
The aim of this research was estimation and comparison of denitrification rate in the Sulejów Reservoir using two methods: 1). the in situ chamber method – the denitrification rate was calculated from the total N2 flux out of the sediment, measured directly by gas chromatography and ranged from 0 to 677 μmoll N2 m-2 h-1. 2). occurrence of denitrifying bacteria – determined by means of the most probable number (MPN) and plate counting (PC). Environmental conditions determining denitrification process in the Sulejow Reservoir was also identified. The positive correlation between the content of organic carbon in the sediments and the amount of denitrifying bacteria (r=0.86) and denitrification rate (r=0.84) was indicated. The number of denitrifying bacteria in the sediment was estimated at 0.05% to 15.8% of total microflora by MPN, and at 4.6% to 26% using PC. The most frequently isolated bacteria were identified as members of the genera Pseudomonas, Alcaligenes and Bacillus. About 50% of the bacterial strains isolated accumulated nitrite during nitrate reduction.