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{| class="model-ib" style="float:right; margin-left:1em; margin-bottom:1em;" ! Phosphate uptake (³²P) |- | '''Approach:''' radiotracer (³²P-phosphate) incubation |- | '''Context:''' incubation, lab |- | '''Spatial scale:''' point sample |- | '''Temporal sca..."

2026-05-13T00:01:59Z

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;" ! Phosphate uptake (32P) |- | '''Approach:''' radiotracer (32P-phosphate) incubation |- | '''Context:''' incubation, lab |- | '''Spatial scale:''' point sample |- | '''Temporal sca..."

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* [[Page authors|Page authors]]: [[PRIMO]]
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<div class="model-box">
{| class="model-ib" style="float:right; margin-left:1em; margin-bottom:1em;"
! Phosphate uptake (32P)
|-
| '''Approach:''' radiotracer (32P-phosphate) incubation
|-
| '''Context:''' incubation, lab
|-
| '''Spatial scale:''' point sample
|-
| '''Temporal scale:''' hours to days
|-
| '''Units:''' mol P L-1 h-1
|-
| '''Community captured:''' microalgae and bacteria
|-
| '''Co-measurements:''' cell abundance
|}
</div>
<div style="clear:both"></div>

== Method Overview ==

Phosphate uptake rates are measured by adding 32P-labelled inorganic phosphate (H332PO4) at tracer concentrations to seawater samples. Organisms take up the radiolabelled phosphate, and the amount incorporated into particulate material is measured after filtration onto polycarbonate membranes (0.2 or 0.7 µm) by liquid scintillation counting. The uptake rate is calculated from the fraction of added 32P incorporated relative to the ambient + added phosphate concentration<ref name="Duhamel2017">Duhamel, S., Björkman, K. M., Doggett, J. K., & Karl, D. M. (2017). Phosphorus dynamics in biogeochemically distinct regions of the southeast subtropical Pacific Ocean. ''Progress in Oceanography'', 151, 261–274. https://doi.org/10.1016/j.pocean.2016.12.007</ref>.

=== Scale of measurement ===

Sampling after hours to days incubation. Short incubations are preferred to minimize isotope dilution and bottle effects.

=== Data generated ===

Phosphate uptake rates (mol P L-1 h-1), reflecting the rate at which the community assimilates inorganic phosphate. At saturating substrate, Vmax is obtained. Under near-ambient conditions, the ''in situ'' uptake rate is approximated.

=== Units & currency ===

Units are mol P L-1 h-1. The currency is phosphorus.

=== Sample size ===

Typical samples are < 1 L in volume.

=== Repositories & databases ===

== Limitations ==

Rates represent Vmax when substrate is added at saturating concentrations. Isotope dilution from ongoing regeneration of unlabelled Pi during the incubation can cause underestimation. 32P is a high-energy beta emitter requiring appropriate radiation safety protocols. Bottle effects apply.

== Example Applications & Protocols ==

=== Classic examples ===
* Duhamel et al. (2017) ''Phosphorus dynamics in biogeochemically distinct regions of the southeast subtropical Pacific Ocean'' <ref name="Duhamel2017" />

=== Recent applications ===
*

=== Common calculations/conversions ===
* P uptake rate (nmol P L-1 h-1) = (cpmfilter / cpmtotal added) × [Pi,total] / incubation time; where [Pi,total] = [ambient Pi] + [32P added].

== References ==

[[Category:Main Pages|Model types]]

32-P incorporation - Revision history