# Geochemical constraints on the rates and fates of nitrogen fixation in the southwest Pacific

> **NSF 01002526DB NSF RESEARCH & RELATED ACTIVIT** · Texas A&M University (TX) · $498,457

## Abstract

The base of the marine food web consists of phytoplankton, or microscopic plants that need to be fertilized by the elements nitrogen (N), phosphorus (P), and iron (Fe), to grow and sustain global fisheries. The ultimate source of N to the ocean, and thus to marine phytoplankton, is provided by marine microbes that carry out a process known as N fixation. While N is an essential component of phytoplankton biomass, we do not have good estimates of the locations, times, or magnitudes when N fixation occurs in the ocean. Without knowing where and how much N phytoplankton obtain from N fixation we cannot accurately predict the capacity of the ocean to support fish stocks and their ability to withstand environmental changes. The southwest Pacific Ocean has some of the highest rates of N fixation in the global ocean, but we don’t have a complete understanding of the fate of newly fixed N, or how it may change depending on which microbes carry out N fixation. This project seeks to track the fate of N from N fixation using geochemical tools in a collaboration with French scientists. French colleagues will collect samples to be sent to Texas A&M University for analysis. The French scientists will also share data that will be used to interpret the geochemical measurements made as part of this study. Together, this information will be used to understand the fate of newly fixed N. Specifically, the study will examine whether newly fixed N is retained in the surface ocean in a form that ph

## Key facts

- **NSF award ID:** 2525151
- **Awardee organization:** Texas A&M University (TX)
- **SAM.gov UEI:** JF6XLNB4CDJ5
- **PI:** Angela N Knapp
- **Primary program:** 01002526DB NSF RESEARCH & RELATED ACTIVIT
- **All programs:** Marine Nitrogen Cycle
- **Estimated total:** $498,457
- **Funds obligated:** $498,457
- **Transaction type:** Standard Grant
- **Period:** 08/15/2025 → 07/31/2028

## Primary source

NSF Award Search: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2525151

## Citation

> US National Science Foundation, Award 2525151, Geochemical constraints on the rates and fates of nitrogen fixation in the southwest Pacific. Retrieved via AI Analytics 2026-06-06 from https://api.ai-analytics.org/grant/nsf/2525151. Licensed CC0.

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