Influence of Sulfide Inhibition of Nitrification on Nitrogen Regeneration in Sediments

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Science  27 Oct 1995:
Vol. 270, Issue 5236, pp. 623-625
DOI: 10.1126/science.270.5236.623


Nitrification, a central process in the nitrogen cycle, converts ammonium to nitrite or nitrate. In experiments with estuarine sediment, addition of 60 and 100 μM hydrogen sulfide (HS) reduced nitrification by 50 and 100 percent, respectively. Aerobic incubation of ammonium-enriched sediment slurries showed that previous HS exposure reduced nitrification for at least 24 hours; nitrification rates recovered slowly after one-time HS exposure. Sulfide inhibition of nitrification could limit nitrogen loss through coupled nitrification-denitrification and may contribute to the previously observed difference in net nitrogen cycling between freshwater and marine sediments. This interaction could also exacerbate eutrophication in coastal environments.