Inhibition of denitrification by hydrocarbons in marine sediments. Role of Nereis diversicolor

An in vitro experiment has been carried out in order to illustrate the influence of the burrowing polychaete Nereis diversicolor on denitrification in hydrocarbon-loaded sediments. After 15 and 45 days, the denitrification activity in the different contaminated or non-contaminated control (without macro-fauna) and experimental (colonized by polychaetes) sediments was compared. In control contaminated sediments, the inhibition of denitrification is solely located in the surface layer (0-2 cm). In the presence of polychaetes, the hydrocarbon buried in the burrows extends the inhibition of denitrification in the sediment. As a function of the quantity of buried hydrocarbon, the inhibition of denitrification is observed up to a depth of 6 and 10 cm, after 15 and 45 days, respectively.