A Critical Review of the ¹⁵N₂ Tracer Method to Measure Diazotrophic Production in Pelagic Ecosystems

Authors

Angelicque E. White
Julie Granger
Corday Seldon, Old Dominion University
Mary R. Gradoville
Lindsey Potts
Annie Bourbonnais
Robinson W. Fulweiler
Angela N. Knapp
Wiebke Mohr
Pia H. Moisander
Craig R. Tobias
Mathieu Caffin
Samuel T. Wilson
Mar Benavides
Sophie Bonnet
Margaret R. Mulholland, Old Dominion UniversityFollow
Bonnie X. Chang

ORCID

0000-0001-8819-189X (Mulholland)

Document Type

Article

Publication Date

4-2020

DOI

10.1002/lom3.10353

Publication Title

Limnology and Oceanography: Methods

Volume

18

Issue

4

Pages

129-147

Abstract

Dinitrogen (N₂) fixation is an important source of biologically reactive nitrogen (N) to the global ocean. The magnitude of this flux, however, remains uncertain, in part because N₂ fixation rates have been estimated following divergent protocols and because associated levels of uncertainty are seldom reported—confounding comparison and extrapolation of rate measurements. A growing number of reports of relatively low but potentially significant rates of N₂ fixation in regions such as oxygen minimum zones, the mesopelagic water column of the tropical and subtropical oceans, and polar waters further highlights the need for standardized methodological protocols for measurements of N₂ fixation rates and for calculations of detection limits and propagated error terms. To this end, we examine current protocols of the ¹⁵N₂ tracer method used for estimating diazotrophic rates, present results of experiments testing the validity of specific practices, and describe established metrics for reporting detection limits. We put forth a set of recommendations for best practices to estimate N₂ fixation rates using ¹⁵N₂ tracer, with the goal of fostering transparency in reporting sources of uncertainty in estimates, and to render N₂ fixation rate estimates intercomparable among studies.

Rights

© 2020 The Authors. Limnology and Oceanography: Methods published by Wiley Periodicals, Inc. on behalf of Association for the Sciences of Limnology and Oceanography.

This is an open access article under the terms of the Creative Commons Attribution-NonCommercial License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited and is not used for commercial purposes.

Data Availability

Article states: "Data from this work are archived with BCO-DMO (Moisander et al. 2019)."

BCO-DMO link to data from Moisander et al. (2019) reference is doi:10.1575/1912/bco-dmo.778000.1

Original Publication Citation

White, A. E., Granger, J., Selden, C., Gradoville, M. R., Potts, L., Bourbonnais, A., ... & Tobias, C. R. (2020). A critical review of the ¹⁵N₂ tracer method to measure diazotrophic production in pelagic ecosystems. Limnology and Oceanography: Methods, 18(4), 129-147. doi:10.1002/lom3.10353

Repository Citation

White, Angelicque E.; Granger, Julie; Seldon, Corday; Gradoville, Mary R.; Potts, Lindsey; Bourbonnais, Annie; Fulweiler, Robinson W.; Knapp, Angela N.; Mohr, Wiebke; Moisander, Pia H.; Tobias, Craig R.; Caffin, Mathieu; Wilson, Samuel T.; Benavides, Mar; Bonnet, Sophie; Mulholland, Margaret R.; and Chang, Bonnie X., "A Critical Review of the ¹⁵N₂ Tracer Method to Measure Diazotrophic Production in Pelagic Ecosystems" (2020). OES Faculty Publications. 385.
https://digitalcommons.odu.edu/oeas_fac_pubs/385