Nitrite (NO2 −) in soils has been observed under a variety of field conditions. The formation 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 the production of NO2 − under iron-reducing conditions, in the absence of an initial nitrate pool. These experiments were performed either in a riparian wetland in New Jersey or in laboratory experiments using soils from the same location. The rates of use of NO2 − and ammonium (NH4 +) determined in situ by performing push-pull experiments were of the same magnitude, supporting the observation of a steady-state NO2 − pool under such anaerobic conditions. An isotope experiment performed with 15NH4 + conclusively showed an existence of a pathway linking NH4 + to dinitrogen gas under anaerobic iron-reducing conditions, in the absence of initial nitrate or NO2 −. Such observations indicate a possibility for the complete removal of NH4 + from wetland soils under anaerobic conditions that develop when soils are water saturated.
1Department of Civil and Environmental Engineering, Princeton University, Princeton, NJ 08544. Dr. Jaffe is corresponding author. E-mail: email@example.com
2Center for Environmental Studies, Brown University, Providence, RI 02912.
3Department of Ecology, Evolution & Natural Resources, Cook College, Rutgers University, New Brunswick, NJ.
Received June 29, 2008, and in revised form Dec. 10, 2008.
Accepted for publication Dec. 11, 2008.