Symbiotic unicellular cyanobacteria fix nitrogen in the Arctic Ocean

Authors

K. Harding
K. A. Turk-Kubo
Rachel E. Sipler, Virginia Institute of Marine Science
M. M. Mills
D. A. Bronk, Virginia Institute of Marine ScienceFollow

Document Type

Article

Department/Program

Virginia Institute of Marine Science

Publication Date

12-2018

Journal

Proceedings of the National Academy of Sciences of the United States of America

Volume

115

Issue

52

First Page

13371

Abstract

Biological dinitrogen (N2) fixation is an important source of nitrogen (N) in low-latitude open oceans. The unusual N2-fixing unicellular cyanobacteria (UCYN-A)/haptophyte symbiosis has been found in an increasing number of unexpected environments, including northern waters of the Danish Straight and Bering and Chukchi Seas. We used nanoscale secondary ion mass spectrometry (nanoSIMS) to measure 15N2 uptake into UCYN-A/haptophyte symbiosis and found that UCYN-A strains identical to low-latitude strains are fixing N2 in the Bering and Chukchi Seas, at rates comparable to subtropical waters. These results show definitively that cyanobacterial N2 fixation is not constrained to subtropical waters, challenging paradigms and models of global N2 fixation. The Arctic is particularly sensitive to climate change, and N2 fixation may increase in Arctic waters under future climate scenarios.

DOI

10.1073/pnas.1813658115

Creative Commons License

This work is licensed under a Creative Commons Attribution 4.0 International License.

Recommended Citation

Harding, K.; Turk-Kubo, K. A.; Sipler, Rachel E.; Mills, M. M.; and Bronk, D. A., Symbiotic unicellular cyanobacteria fix nitrogen in the Arctic Ocean (2018). Proceedings of the National Academy of Sciences of the United States of America, 115(52), 13371.

10.1073/pnas.1813658115