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Dominance, drivers and thresholds of DEN, ANA, and DNRA quantified using a global dataset of cross-ecosystems and machine-learning

Year: 2026

Type: article

Abstract: Nitrogen retention and loss in the critical zone are regulated by denitrification (DEN), anaerobic ammonium oxidation (ANA) and dissimilatory nitrate reduction to ammonium (DNRA), yet their global partitioning remains uncertain. A global dataset from 72 studies reporting DEN, ANA and DNRA rates plus environmental variables and functional genes was analyzed using random forests, generalized additive models and mixed-effects gene-rate analyses. Across ecosystems, contributions followed DEN (66.3%) > DNRA (21.9%) > ANA (11.8%). Wetlands showed consistently elevated DEN rates (mean 11.35 nmol N g⁻¹ h⁻¹) and the strongest ANA activity (mean 1.39 nmol N g⁻¹ h⁻¹), supporting moisture-rich systems as hotspots for DEN and ANA whereas highlands showed the highest relative DNRA (37.8% contribution; 6.89 nmol N g⁻¹ h⁻¹). Seven principal components explained 63.4% of the variance, highlighting critical zone organic matter pools, anaerobic metabolic intensity, and critical zone moisture and nutrient availability as the main environmental controls. Random forest models indicated that NO₃⁻ is the primary predictor for DEN and ANA (together with moisture and temperature/carbon supply), while DNRA is driven more strongly by NH₄⁺ (together with precipitation and temperature). DEN and ANA initially related to moisture negatively then positively at inflection points of about 15%. All processes were associated with hzsB, but correlations were weaker for DNRA. Together, these findings fill a key gap by providing a global, cross-ecosystem synthesis that jointly quantifies the rates, drivers, thresholds, and functional gene-rate associations of DEN, ANA, and DNRA.

Source: Scientific Reports

DOI: 10.1038/s41598-026-59231-1

Authors: Yao Ma, Yao Ma, Song Jiang, Yibing Ma, Yibing Ma

Institutions: Macau University of Science and Technology, National Observation and Research Station of Coastal Ecological Environments in Macao

Language: English

Topic: Soil Carbon and Nitrogen Dynamics

Subfield: Soil Science

Field: Agricultural and Biological Sciences

Domain: Life Sciences

SDGs: Clean water and sanitation, Climate action, Life on land

Open Access status: gold

Estimated APC paid: $2,690