Nitrite Production from Ammonium in Riparian Wetland Soils and Determination of Rates of Consumption of Nitrite and Ammonium in-situ

Nitrite accumulation in soil has been observed under a variety of conditions. The accumulation of NO2- in soils is possible during nitrification or denitrification depending on the soil conditions. This study presents a series of experiments performed at different scales that demonstrate accumulation and production of nitrite under iron reducing conditions, in absence of an initial nitrate pool. These experiments were performed either directly in a riparian wetland in New Jersey, or in laboratory experiments with soils from the same location. The rates of utilization of nitrite and ammonium in situ determined by performing pushpull experiments were of the same magnitude, supporting the observation of a steady state nitrite pool under such anaerobic conditions. An isotope experiment performed with 15NH4 conclusively showed ammonium to be the source of nitrite under the experimental conditions and existence of a pathway linking ammonium and dinitrogen gas under anaerobic conditions.