The role of nitrifier denitrification in the production of nitrous oxide revisited

authored by

Nicole Wrage-Mönnig, Marcus A. Horn, Reinhard Well, Christoph Müller, Gerard Velthof, Oene Oenema

Abstract

Nitrifier denitrification is the reduction of nitrite (NO₂ ⁻) by ammonia-oxidizing bacteria. This process may account for up to 100% of nitrous oxide (N₂O) emissions from ammonium (NH₄ ⁺) in soils and is more significant than classical denitrification under some conditions. Investigations of nitrifier denitrification have expanded in the last decade but many aspects are still not understood. In this review, we revisit our 2001 paper, present a comprehensive summary of current knowledge concerning nitrifier denitrification, and identify the many research needs. Nitrifier denitrification can be distinguished from other routes of N₂O production using isotopic methods: either isotopomer techniques or a combination of ¹⁵N and ¹⁸O tracers. Our understanding of the regulation and conditions favouring nitrifier denitrification has improved over the last decade as a result of adopting molecular and modelling approaches. Environments low in oxygen, and especially those with fluctuating aerobic-anaerobic conditions, promote N₂O production by nitrifier denitrification. Also, large NO₂ ⁻ concentrations, which often arise following inputs of ammonium or urea, may be linked to changes in aerobicity and high pH and favour nitrifier denitrification. The effects of temperature and carbon contents on nitrifier denitrification are incompletely understood and future research needs include: the study of pathways similar to nitrifier denitrification in archaea and nitrite oxidizers; the effects of interactions among microorganisms and between microorganism and plants; and the regulation and importance of the enzymes involved. A comparison and evaluation of the methods used for differentiating the sources of N₂O is urgently needed. Furthermore, results from studies of freshwater and marine environments as well as wastewater treatment, where nitrifier denitrification is also known as nitrous aerobic denitritation (up to N₂O) or aerobic denitritation (up to N₂), will further advance our understanding.

Organisation(s)

Institute of Microbiology

External Organisation(s)

University of Rostock
Johann Heinrich von Thünen Institute, Federal Research Institute for Rural Areas, Forestry and Fisheries
Justus Liebig University Giessen
University College Dublin
Wageningen University and Research

Type

Article

Journal

Soil Biology and Biochemistry

Volume

123

Pages

A3-A16

ISSN

0038-0717

Publication date

08.2018

Publication status

Published

ASJC Scopus subject areas

Microbiology, Soil Science

Sustainable Development Goals

SDG 6 - Clean Water and Sanitation, SDG 14 - Life Below Water

Electronic version(s)

https://doi.org/10.15488/15945 (Access: Open)
https://doi.org/10.1016/j.soilbio.2018.03.020 (Access: Closed)