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Updated: Jul 17, 2026
08:05
Measurement of the Potential Rates of Dissimilatory Nitrate Reduction to Ammonium Based on 14NH4+/15NH4+ Analyses via Sequential Conversion to N2O
Published on: October 7, 2020
Denitrification across landscapes and waterscapes: a synthesis
S Seitzinger1, J A Harrison, J K Böhlke
1Rutgers University, Institute of Marine and Coastal Sciences, Rutgers/NOAA CMER Program, 71 Dudley Road, New Brunswick, New Jersey 08901, USA. sybil@marine.rutgers.edu
Summary
Denitrification removes bioavailable nitrogen across ecosystems. Global models show continental shelves are key, but terrestrial soils and freshwater systems also play vital roles in nitrogen removal.
Area of Science:
- Environmental Science
- Biogeochemistry
- Ecology
Background:
- Denitrification is crucial for removing bioavailable nitrogen (N) from various ecosystems.
- Research on denitrification has been siloed within terrestrial, freshwater, and marine systems, limiting cross-disciplinary understanding.
- Understanding denitrification across ecosystem types is essential for managing nitrogen pollution.
Purpose of the Study:
- To compare denitrification rates and controlling factors across diverse ecosystem types.
- To organize ecosystems along a continuum based on the coupling of nitrification and denitrification.
- To identify key global and watershed-scale drivers and locations of denitrification.
Main Methods:
- Comparative analysis of denitrification rates and controlling factors across terrestrial, freshwater, and marine systems.
- Development of a conceptual continuum model for nitrification-denitrification coupling.
- Utilization of spatially distributed global models to estimate denitrification contributions.
Main Results:
- Continental shelf sediments account for the largest share (44%) of global denitrification, followed by terrestrial soils (22%) and oceanic oxygen minimum zones (OMZs; 14%).
- Freshwater systems contribute approximately 20% and estuaries 1% to global denitrification.
- Terrestrial soils and groundwater are significant for watershed-scale denitrification, but per-area rates are lower than in aquatic systems.
Conclusions:
- Denitrification processes can be viewed along a continuum from tightly coupled to decoupled nitrification and denitrification.
- Aquatic ecosystem denitrification is influenced by nitrogen inputs, hydrology, and geomorphology, with similar relationships observed across various aquatic types.
- While landscape-based approaches to increase denitrification exist, their effectiveness at watershed scales for reducing nitrogen export requires further testing.
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