Global Fjords as Minor Sources of Nitrous Oxide to the Atmosphere

Abstract We report high‐resolution observations of N2O sea‐air fluxes at six fjords spanning arctic, subarctic, and temperate climates. Icelandic and Swedish fjords were sources of N2O at 97.6 ± 10.5 and 19.9 ± 19.3 μg N2O m−2 day−1, respectively. These fjords showed increasing N2O concentrations to...

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Main Authors: T. Politi, Y. Y. Yau, I. R. Santos, A. Cabral, H. L. S. Cheung, C. Majtényi‐Hill, A. Ulfsbo, A. Wåhlin, S. Bonaglia
Format: Article
Language:English
Published: Wiley 2025-02-01
Series:Geophysical Research Letters
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Online Access:https://doi.org/10.1029/2024GL111624
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Summary:Abstract We report high‐resolution observations of N2O sea‐air fluxes at six fjords spanning arctic, subarctic, and temperate climates. Icelandic and Swedish fjords were sources of N2O at 97.6 ± 10.5 and 19.9 ± 19.3 μg N2O m−2 day−1, respectively. These fjords showed increasing N2O concentrations toward the head. In contrast, a Greenland fjord exhibited net N2O uptake at −8.3 ± 7.8 μg N2O m−2 day−1 with decreasing concentration toward the head of the fjord. Individual fjords appear to have unique N2O drivers such as temperature, salinity, chlorophyll, and pH but no overarching driver was identified across all fjords. In Icelandic and Swedish fjords, low oxygen in subsurface waters and aquaculture activities may have enhanced N2O emissions. Globally, fjords release 7.9 ± 1.7 Gg N2O yr−1 to the atmosphere, which represents 2%–13% of global emissions from coastal ecosystems. These N2O emissions offset 3.5% of CO2 sequestration in fjords.
ISSN:0094-8276
1944-8007