N-Fixation Working Group

Developing best practices for measurement of oceanic 15N2 fixation rates and relationships to communities - PIs: Angelicque White (Oregon State Univ.), Pia Moisander (UMass Dartmouth), Julie Granger (Univ. Conn.)

Objective: Using field and laboratory data from a recently funded NSF EAGER award, this working group will conduct a thorough assessment of the 15N2 tracer incubation method (accuracy, error analysis, detection limit, etc.) for measuring nitrogen fixation rates and accompanying molecular methods that identify responsible diazotrophs.

BREAKING  NEWS: New paper published by working group members

White, A.E., Granger, J., Selden, C., Gradoville, M.R., Potts, L., Bourbonnais, A., Fulweiler, R.W., Knapp, A.N., Mohr, W., Moisander, P.H., Tobias, C.R., Caffin, M., Wilson, S.T., Benavides, M., Bonnet, S., Mulholland, M.R. and Chang, B.X. (2020), A critical review of the 15N2 tracer method to measure diazotrophic production in pelagic ecosystems. Limnol Oceanogr Methods. doi:10.1002/lom3.10353

Diazotroph quantitative PCR (meta)datasheet

The link below is to a (meta)datasheet we recommend using when reporting marine diazotroph qPCR data in publications and submissions to databases.
qPCR datasheet 

DiaRy: Diazotroph primer-probe libraRy for qPCR

DiaRy is a collection of all quantitative PCR primer-probe sets we have found in the literature that are targeting the nifH gene in marine and estuarine diazotrophs. Please contact us with any additions, corrections, or comments.

15N2 Contaminant Database

Enter your data (Form)

View Spreadsheet


Metadata: 15N tracer incubations for N2 fixation measurements

Enter your data (Form)

View Spreadsheet

News and Resources

  • May 31-June 1, 2018: Working Group Meeting (Boston, MA) Agenda
  • February 15, 2018: OSM Town Hall (Portland, OR) Meeting Notes
  • September 1, 2017: First Working Group teleconference

Working Group Members

Mar BenavidesUniv. of Copenhagen, Denmark

Ilana Berman-Frank - Bar-Ilan Univ.

Sophie Bonnet - Mediterranean Institute of Oceanology

Annie Bourbonnais - Univ. South Carolina

Bonnie Chang - Univ. of Washington

Dreux Chappell - Old Dominion Univ.

Anne Dekas - Stanford Univ.

Wally Fulweiler - Boston Univ.

Rosie Gradoville - Oregon State Univ.

Julie Granger - Univ. of Connecticut

Bethany Jenkins - Univ. Rhode Island

Todd Kana - Horn Point Laboratory

Angela Knapp - Florida State Univ.

Etai Landou - Bar-Ilan Univ.

Pia Moisander - Univ. of Massachusetts - Dartmouth

Wiebke Mohr - Max Planck Institute for Marine Microbiology

Margie Mulholland - Old Dominion Univ.

Eric Raes - Alfred Wegener Institute for Polar and Marine Research

Lasse Riemann - Univ. of Copenhagen

Corday Seldon - Old Dominion Univ.

Kendra Turk-Kubo - Univ. California Santa Cruz

Angelicque White - Oregon State Univ.

Sam Wilson - Univ. of Hawaii - Honolulu

Relevant Documents

Tests of different methods of introducing 15N2  investigated by Mahaffey, Rees and Kitidis (2013) - PDF

2012 Kiel Workshop Report - description of problem, summary and minutes, prepared by Jonathan Zehr, Wiebke Mohr, Rebecca Langlois - PDF

Spreadsheet - calculates nitrogen fixation rates and corresponding limits of detection (LOD) for each measured rate.