Dissolved hydrogen and nitrogen fixation in the oligotrophic North Pacific Subtropical Gyre
Article first published online: 10 JUN 2013
© 2013 The Authors. Environmental Microbiology Reports published by John Wiley & Sons Ltd and Society for Applied Microbiology.
This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.
Environmental Microbiology Reports
Volume 5, Issue 5, pages 697–704, October 2013
How to Cite
Wilson, S. T., del Valle, D. A., Robidart, J. C., Zehr, J. P. and Karl, D. M. (2013), Dissolved hydrogen and nitrogen fixation in the oligotrophic North Pacific Subtropical Gyre. Environmental Microbiology Reports, 5: 697–704. doi: 10.1111/1758-2229.12069
- Issue published online: 2 OCT 2013
- Article first published online: 10 JUN 2013
- Accepted manuscript online: 13 MAY 2013 04:19AM EST
- Manuscript Accepted: 5 MAY 2013
- Manuscript Revised: 26 APR 2013
- Manuscript Received: 1 JUL 2012
- Research and Education (C-MORE). Grant Number: EF0424599
- NSF. Grant Number: OCE-1153656
- Gordon and Betty Moore Foundation
Vol. 6, Issue 1, 122, Article first published online: 20 JAN 2014
The production of hydrogen (H2) is an inherent component of biological dinitrogen (N2) fixation, and there have been several studies quantifying H2 production relative to N2 fixation in cultures of diazotrophs. However, conducting the relevant measurements for a field population is more complex as shown by this study of N2 fixation, H2 consumption and dissolved H2 concentrations in the oligotrophic North Pacific Ocean. Measurements of H2 oxidation revealed microbial consumption of H2 was equivalent to 1–7% of ethylene produced during the acetylene reduction assay and 11–63% of 15N2 assimilation on a molar scale. Varying abundances of Crocosphaera and Trichodesmium as revealed by nifH gene abundances broadly corresponded with diel changes observed in both N2 fixation and H2 oxidation. However, no corresponding changes were observed in the dissolved H2 concentrations which remained consistently supersaturated (147–560%) relative to atmospheric equilibrium. The results from this field study allow the efficiency of H2 cycling by natural populations of diazotrophs to be compared to cultured representatives. The findings indicate that dissolved H2 concentrations may depend not only on the community composition of diazotrophs but also upon relevant environmental parameters such as light intensity or the presence of other H2-metabolizing microorganisms.