Work

Diazotroph‐Driven 210 Po Scavenging Reveals a Potential Radiotracer for Marine Nitrogen Fixation

Year: 2026

Type: article

Abstract: The role of phytoplankton, particularly diazotrophs, in affecting in situ 210 Po scavenging has been little investigated. Here, we first report an enhanced 210 Po deficit in a cyclonic eddy core relative to its edge in the subtropical Pacific, coinciding with an elevated integrated nitrogen fixation rate (NFR). In contrast, particulate organic carbon, chlorophyll a , total particulate matter, and 210 Pb show no core‐edge difference, revealing a selective fractionation between 210 Po and 210 Pb during scavenging. The partition coefficient of 210 Po, but not 210 Pb, correlates with NFR. The 210 Po/ 210 Pb fractionation factor also scales with NFR. These relationships indicate diazotrophs' uptake of 210 Po and provide a field data‐based algorithm linking 210 Po disequilibria to NFR in (sub)tropical oceans. Our findings suggest that 210 Po offers a potential radiotracer for quantifying marine NFR, highlighting a new insight to constrain nitrogen cycling in oligotrophic oceans.

Source: Geophysical Research Letters

DOI: 10.1029/2026gl122142

Authors: Weifeng Yang, Hui Shen, Kuanbo Zhou, Feng Ling, Minfang Zheng

Institutions: Xiamen University, State Key Laboratory of Marine Environmental Science, University of Illinois Urbana-Champaign

Language: English

Topic: Marine and coastal ecosystems

Subfield: Oceanography

Field: Earth and Planetary Sciences

Domain: Physical Sciences

SDG: Life below water

Open Access status: gold

Estimated APC paid: $3,190