EVIDENCE FOR DENITRIFICATION IN MARINE SEDIMENT HIGHLY CONTAMINATED BY PETROLEUM-PRODUCTS

Denitrifying activity was measured in marine sediment (mediterranean c oast of France) sampled near a petroleum refinery heavily contaminated by hydrocarbons (31 g kg-1 of sediment). Results provided evidence th at in Lavera Bay sediment chronically polluted by petroleum products, denitrification (potential and estimated activities) was not affected by petroleum input and was comparable to those obtained in unpolluted sediments. However, due to low nitrate concentration natural denitrify ing activity is not detectable. The dominant denitrifying bacteria (85 % of the isolates) belonged to the genus Pseudomonas and four groups o f bacteria could be discriminated. The growth pattern on nitrate was d ifferent for each isolate and one strain was not capable of nitrous ox ide production.