A new mathematical approach for calculating the contribution of anammox, denitrification and atmosphere to an N₂ mixture based on a ¹⁵N tracer technique

Abstract

Denitrification and anaerobic ammonium oxidation (anammox) have been identified as biotic key processes of N2 formation during global nitrogen cycling. Based on the principle of a 15N tracer technique, new analytical expressions have been derived for a calculation of the fractions of N2 simultaneously released by anammox and denitrification. An omnipresent contamination with atmospheric N2 is also taken into account and is furthermore calculable in terms of a fraction. Two different mathematical approaches are presented which permit a precise calculation of the contribution of anammox, denitrification, and atmosphere to a combined N2 mixture. The calculation is based on a single isotopic analysis of a sampled N2 mixture and the determination of the 15N abundance of nitrite and nitrate (simplified approach) or of ammonium, nitrite, and nitrate (comprehensive approach). Calculations are even processable under conditions where all basal educts of anammox and denitrification (ammonium, nitrite, and nitrate) are differently enriched in 15N. An additional determination of concentrations of dissolved N compounds is unnecessary. Finally, the presented approach is transferable to studies focused on terrestrial environments where N2 is formed by denitrification and simultaneously by codenitrification or chemodenitrification.

Distribution and Diversity of Anaerobic Ammonium Oxidation (Anammox) Bacteria in the Sediment of a Eutrophic Freshwater Lake, Lake Kitaura, Japan

“…Furthermore, atmospheric N2 contamination during the sample preparation and gas analysis procedures brings about 0.732% 29 N2, which could also be a cause of overestimation of anammox. Our procedures for calibration were consistent with a theory developed previously (27).…”

Denitrification and nitrous oxide effluxes in boreal, eutrophic river sediments under increasing nitrate load: a laboratory microcosm study

“…and NO 2 -in the sediment nor the contamination of the N 2 pool by airborne nitrogen contamination can be eliminated. Mathematical approaches for separating anammox, denitrification and airborne nitrogen contamination have been presented recently (Thamdrup and Dalsgaard 2002;Risgaard-Petersen et al 2003;Trimmer et al 2006;Spott and Stange 2007). However, all of these approaches require an accurate time-dependent quantification of NO 2 -and are therefore not suitable for this data.…”

Co-Occurring Anammox, Denitrification, and Codenitrification in Agricultural Soils

“…Current denitrification, codenitrification, and anammox calculations based on the production of labeled N 2 cannot fully differentiate the 29 N 2 produced by bacterial codenitrification and anammox (7,25,50). Due to the characteristics of anammox bacteria, which, like other planctomycetes, lack cell walls, antibiotics targeting cell wall synthesis, coupled with fungal inhibitors, may inhibit both bacterial and fungal codenitrification, thereby allowing anammox to be measured separately from bacterial codenitrification (51).…”