Hagi BucknWise: Created page with "{{BreadcrumbsNutrients}} * Page authors: PRIMO * Responsible curator: Hagen Buck-Wiese ---- TOC
{| class="model-ib" style="float:right; margin-left:1em; margin-bottom:1em;" ! Denitrification rate (stoichiometric tracer analysis) |- | '''Approach:''' deviations from Redfield stoichiometry in DIN, O₂, DIC, PO₄ |- | '''Context:''' ''in situ'' |- | '''Spa..."

2026-05-12T23:07:29Z

Created page with "{{BreadcrumbsNutrients}} * Page authors: PRIMO * Responsible curator: Hagen Buck-Wiese ---- __TOC__ <div class="model-box"> {| class="model-ib" style="float:right; margin-left:1em; margin-bottom:1em;" ! Denitrification rate (stoichiometric tracer analysis) |- | '''Approach:''' deviations from Redfield stoichiometry in DIN, O2, DIC, PO4 |- | '''Context:''' ''in situ'' |- | '''Spa..."

New page

{{BreadcrumbsNutrients}}

* [[Page authors|Page authors]]: [[PRIMO]]
* [[Responsible curator|Responsible curator]]: [[User:Hagi BucknWise|Hagen Buck-Wiese]]
----

__TOC__
<div class="model-box">
{| class="model-ib" style="float:right; margin-left:1em; margin-bottom:1em;"
! Denitrification rate (stoichiometric tracer analysis)
|-
| '''Approach:''' deviations from Redfield stoichiometry in DIN, O2, DIC, PO4
|-
| '''Context:''' ''in situ''
|-
| '''Spatial scale:''' ocean-wide to basin
|-
| '''Temporal scale:''' years and beyond
|-
| '''Units:''' mol N time-1
|-
| '''Community captured:''' bulk
|-
| '''Co-measurements:''' deviations from Redfield stoichiometry over time
|}
</div>
<div style="clear:both"></div>

== Method Overview ==

Denitrification leaves a characteristic stoichiometric fingerprint in the water column: it consumes nitrate without a corresponding change in phosphate, causing a negative deviation of the measured N:P ratio from the Redfield ratio (N* = [NO3-] − 16 × [PO43-] + 2.9, or similar formulations). By mapping the spatial distribution of N* across ocean basins and tracking changes in the tracer over time using hydrographic data, the net rate of denitrification (minus N fixation) can be estimated. When combined with inverse circulation models (INCLUDE LINK TO MODEL PAGE HERE?) and oxygen consumption data, the approach provides basin-scale estimates of denitrification rates<ref name="Li2006">Li, Y.-H., & Peng, T.-H. (2006). Nitrate deficits by nitrification and denitrification processes in the Indian Ocean. ''Deep-Sea Research Part I'', 53(1), 94–110. https://doi.org/10.1016/j.dsr.2005.09.009</ref>.

=== Scale of measurement ===

Basin to global scale. Temporal resolution is limited by the timescales of ocean circulation (years to centuries). The method cannot resolve point rates or short-term variability.

=== Data generated ===

Basin-integrated denitrification rates in mol N time-1 or Tg N yr-1; spatial maps of N* revealing regions of net N loss or gain.

=== Units & currency ===

Units are mol N time-1 or Tg N yr-1. The currency is nitrogen.

=== Sample size ===

Not applicable. This method uses existing hydrographic datasets.

=== Repositories & databases ===

Global ocean hydrographic data: [https://www.go-ship.org/ GO-SHIP]; [https://www.ncei.noaa.gov/products/world-ocean-atlas World Ocean Atlas].

== Limitations ==

The approach relies on the assumption that the Redfield ratio accurately describes the elemental stoichiometry of organic matter remineralization in the region of interest. In freshwater or coastal systems, variable stoichiometry makes the approach less reliable. Multiple processes can contribute to N* anomalies (N fixation decreases the deficit; denitrification increases it), and separating them requires additional constraints. Requires inverse circulation models to interpret tracer distributions quantitatively.

== Example Applications & Protocols ==

=== Classic examples ===
* Li & Peng (2006) ''Nitrate deficits by nitrification and denitrification processes in the Indian Ocean'' <ref name="Li2006" />

=== Recent applications ===
* Mashifane (2021) ''Denitrification and anammox shift nutrient stoichiometry in the Benguela upwelling system'' <ref name="Mashifane2021">Mashifane, T. B., Roychoudhury, A. N., Waldron, H. N., Racault, M.-F., & Moloney, C. L. (2021). Denitrification and anammox shift nutrient stoichiometry and the phytoplankton community structure in the Benguela upwelling system. ''Journal of Geophysical Research: Oceans'', 126(8), e2021JC017816. https://doi.org/10.1029/2021JC017816</ref>

=== Common calculations/conversions ===
* N* = [NO3-] − 16 × [PO43-] + 2.9 (µM); negative N* indicates denitrification; positive N* indicates N fixation.

== References ==

[[Category:Main Pages|Model types]]

Stoichiometric approach - Revision history