Examination of dinitrogen (N2) fixation in the Eastern Tropical South Pacific oxygen deficient zone has raised questions about the range of diazotrophs in the deep sea and their quantitative importance as a source of new nitrogen globally. However, technical considerations in the deployment of stable isotopes in quantifying N2fixation rates have complicated interpretation of this research. Here, we report the findings of a comprehensive survey of N2fixation within, above and below the Eastern Tropical South Pacific oxygen deficient zone. N2fixation rates were measured using a robust15N tracer method (bubble removal) that accounts for the slow dissolution of N2gas and calculated using a conservative approach. N2fixation was only detected in a subset of samples (8 of 125 replicated measurements) collected within suboxic waters (< 20
Recent work has suggested that the oxygen deficient zone (ODZ) and overlying surface waters of the eastern tropical South Pacific (ETSP) is a potential niche for dinitrogen (N2) fixation. Rates of dinitrogen fixation were measured in the ETSP above and within the ODZ in July 2013 using a modified15N2bubble addition method, wherein a bubble was added, mixed, and then removed, and the isotopic enrichment of the dissolved N2was measured directly for each incubation. N2fixation rates in the euphotic zone ranged from below detection to 3.9 nmol L−1d−1and were below detection at all depths surveyed within the ODZ. Depth‐integrated rates ranged from below detection to 289.7
- PAR ID:
- 10460138
- Publisher / Repository:
- Wiley Blackwell (John Wiley & Sons)
- Date Published:
- Journal Name:
- Limnology and Oceanography
- Volume:
- 64
- Issue:
- 5
- ISSN:
- 0024-3590
- Page Range / eLocation ID:
- p. 1913-1923
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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