TY - JOUR
T1 - Revisiting process-based simulations of soil nitrite dynamics
T2 - Tighter cycling between nitrite and nitrate than considered previously
AU - Zheng, Jinsen
AU - Fujii, Kazumichi
AU - Koba, Keisuke
AU - Wanek, Wolfgang
AU - Müller, Christoph
AU - Jansen-Willems, Anne B.
AU - Nakajima, Yasuhiro
AU - Wagai, Rota
AU - Canarini, Alberto
N1 - Publisher Copyright:
© 2023 Elsevier Ltd
PY - 2023/3/1
Y1 - 2023/3/1
N2 - Nitrite is an important precursor of many environmentally hazardous compounds (e.g., nitrate, nitrous oxide, and nitrous acid). However, its dynamics in the soil environment are not yet fully understood. The NtraceNitrite tool has been successful in analyzing 15N tracing data. Here, based on a 15N tracing experiment (under aerobic condition) where either the nitrite, the nitrate, or the ammonium pool was labelled, we developed an extended model (NO2Trace), which was featured by the addition of coupled nitrate reduction and nitrite re-oxidation and the separation of the nitrate pool in two sub-pools. With 5 additional parameters optimized, NO2Trace was able to achieve a superior fit to the data, as compared to the NtraceNitrite tool. The additional features might offer a suitable explanation for the isotopic composition of nitrate produced via nitrification in terrestrial ecosystems. Our results carry two important implications: (i) a key assumption of the classical isotope pool dilution technique (i.e., no reflux of tracer) for estimating gross nitrate fluxes is violated, leading to considerable underestimations (22–99% in the datasets tested); (ii) re-oxidation can dominate the consumption (∼75%) of nitrite derived from nitrate reduction, indicating the potential of this process as a target for nitrogen retention mechanism against gaseous nitrogen losses (through nitrite reduction). The additional features of the extended model show a tighter cycle between soil nitrite and nitrate than considered previously and provide a more comprehensive description of soil nitrite transformations. This study also highlights that more work is needed to develop methods capable of separating process- and pathways-specific nitrate and nitrite pools.
AB - Nitrite is an important precursor of many environmentally hazardous compounds (e.g., nitrate, nitrous oxide, and nitrous acid). However, its dynamics in the soil environment are not yet fully understood. The NtraceNitrite tool has been successful in analyzing 15N tracing data. Here, based on a 15N tracing experiment (under aerobic condition) where either the nitrite, the nitrate, or the ammonium pool was labelled, we developed an extended model (NO2Trace), which was featured by the addition of coupled nitrate reduction and nitrite re-oxidation and the separation of the nitrate pool in two sub-pools. With 5 additional parameters optimized, NO2Trace was able to achieve a superior fit to the data, as compared to the NtraceNitrite tool. The additional features might offer a suitable explanation for the isotopic composition of nitrate produced via nitrification in terrestrial ecosystems. Our results carry two important implications: (i) a key assumption of the classical isotope pool dilution technique (i.e., no reflux of tracer) for estimating gross nitrate fluxes is violated, leading to considerable underestimations (22–99% in the datasets tested); (ii) re-oxidation can dominate the consumption (∼75%) of nitrite derived from nitrate reduction, indicating the potential of this process as a target for nitrogen retention mechanism against gaseous nitrogen losses (through nitrite reduction). The additional features of the extended model show a tighter cycle between soil nitrite and nitrate than considered previously and provide a more comprehensive description of soil nitrite transformations. This study also highlights that more work is needed to develop methods capable of separating process- and pathways-specific nitrate and nitrite pools.
KW - 15N tracing
KW - numerical simulation
KW - nitrite dynamic
KW - nitraite reduction
KW - nitrite re-oxidation
KW - N tracing
KW - Numerical simulation
KW - Nitrite dynamic
KW - Nitrite re-oxidation
KW - Nitrate reduction
UR - http://www.scopus.com/inward/record.url?scp=85146874733&partnerID=8YFLogxK
U2 - 10.1016/j.soilbio.2023.108958
DO - 10.1016/j.soilbio.2023.108958
M3 - Article
VL - 178
JO - Soil Biology and Biochemistry
JF - Soil Biology and Biochemistry
SN - 0038-0717
M1 - 108958
ER -