Lj. Garciagil et Hl. Golterman, KINETICS OF FES-MEDIATED DENITRIFICATION IN SEDIMENTS FROM THE CAMARGUE (RHONE DELTA, SOUTHERN FRANCE), FEMS microbiology, ecology, 13(2), 1993, pp. 85-91
Denitrification rates were measured in sediments after the addition of
different concentrations of FeS. A decrease of the denitrification ra
te was observed when high concentrations of ferrous iron (> 10 mM) wer
e present. In the experiments with no significant concentrations of fr
ee Fe2+, the relationship between NO3- reduction and FeS concentration
followed Michaelis and Menten kinetics. The maximum rate was 0.273 mm
ol l(-1) d(-1), 6 times as much as the basal rate 0.046 mmol l(-1) d(-
1), which was attributed to organic matter; the K-s was 1.45 mM FeS. T
he stoichiometry of the overall reaction involving NO3- reduction and
the concomitant S2- oxidation was also investigated. Measured Delta S/
Delta N ratios ranged between 0.55 and 0.64, with Sigma H2S+SO42- chan
ging less than 10%. These values agree with the theoretically expected
value of 0.56.