Denitrification potential of epilithic communities in a lotic environment

Denitrification potentials of epilithic microbial populations were assessed using the acetylene inhibition method, in which acetylene is used to block the reduction of nitrous oxide (N sub(2)O) to nitrogen (N sub(2)). Samples of the epilithic community were incubated in filtered river water containing modified Bushnell-Haas salts, glycerol, and yeast extract--under aerobic and anaerobic acetylene atmospheres. Denitrification potentials were typically higher when nitrite was the added electron acceptor. The rates of denitrification were temperature- and carbon-dependent and the maximum rate, 8.53 mu g N sub(2)O-N per cm super(2) per day occurred at 23 degree C when nitrite was the electron acceptor.