Long-term nitrogen burial exceeds denitrification in global fjords

Henry L. S. Cheung; Lubrina S. Levin; Craig Smeaton; Tobia  Politi; Bo  Thamdrup; Isaac R. Santos; Stefano  Bonaglia

doi:10.1038/s41467-026-71116-5

Long-term nitrogen burial exceeds denitrification in global fjords

Henry L. S. Cheung^*, Lubrina S. Levin, Craig Smeaton, Tobia Politi, Bo Thamdrup, Isaac R. Santos, Stefano Bonaglia

^*Corresponding author for this work

Research output: Contribution to journal › Article › peer-review

Abstract

Nitrogen (N) availability regulates primary productivity and hence directly affects global oceanic carbon sequestration. Global fjords account for up to 11% of marine carbon burial. However, N loss via sediment burial remains largely unquantified. Here, we show that global fjords are hotspots of N burial, accounting for up to 18% of oceanic N burial despite only covering 0.1% of the ocean area. Burial is the dominant N loss mechanism, exceeding microbial N loss via denitrification and anammox, which are generally considered the major N loss mechanisms. Microbial N loss dominates in anoxic fjords and appears to be a function of temperature and nutrient availability. Overall, fjords efficiently sequester excess N in sediments over long time scales. Accelerated warming will promote both N burial from increased primary production and microbial N loss from warmer temperatures, affecting N budgets in fjords and in the ocean in general.

Original language	English
Article number	3148
Number of pages	9
Journal	Nature Communications
Volume	17
DOIs	https://doi.org/10.1038/s41467-026-71116-5
Publication status	Published - 1 Apr 2026

UN SDGs

This output contributes to the following UN Sustainable Development Goals (SDGs)

SDG 13 Climate Action
SDG 14 Life Below Water

Keywords

Fjords
Nitrogen
Loss
Sediment
Water column
Seabed
Coastal
O2 depletion
Oxygen
Burial

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10.1038/s41467-026-71116-5Licence: CC BY

Cheung_2026_NC_Long-term-nitrogen-burial-fjords_CC
© The Author(s) 2026. This article is licensed under a Creative Commons Attribution 4.0 International License (https://creativecommons.org/licenses/by/4.0/), which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made.
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Dataset and Markdown codes for article "Long-term nitrogen burial exceeds denitrification in global fjords"
Cheung, H. L. (Creator), Levin, L. (Creator), Smeaton, C. (Creator), Politi, T. (Creator), Thamdrup, B. (Creator), Santos, I. (Creator) & Bonaglia, S. (Creator), Zenodo, 5 Mar 2026
DOI: 10.5281/zenodo.17257260
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@article{c43013606a9d4f9ab1c34f24e663536a,

title = "Long-term nitrogen burial exceeds denitrification in global fjords",

abstract = "Nitrogen (N) availability regulates primary productivity and hence directly affects global oceanic carbon sequestration. Global fjords account for up to 11\% of marine carbon burial. However, N loss via sediment burial remains largely unquantified. Here, we show that global fjords are hotspots of N burial, accounting for up to 18\% of oceanic N burial despite only covering 0.1\% of the ocean area. Burial is the dominant N loss mechanism, exceeding microbial N loss via denitrification and anammox, which are generally considered the major N loss mechanisms. Microbial N loss dominates in anoxic fjords and appears to be a function of temperature and nutrient availability. Overall, fjords efficiently sequester excess N in sediments over long time scales. Accelerated warming will promote both N burial from increased primary production and microbial N loss from warmer temperatures, affecting N budgets in fjords and in the ocean in general.",

keywords = "Fjords, Nitrogen, Loss, Sediment, Water column, Seabed, Coastal, O2 depletion, Oxygen, Burial",

author = "Cheung, \{Henry L. S.\} and Levin, \{Lubrina S.\} and Craig Smeaton and Tobia Politi and Bo Thamdrup and Santos, \{Isaac R.\} and Stefano Bonaglia",

note = "Funding: Research funding was provided by the Swedish Research Council VR to S.B. (grant no. 2022-04710). The Iceland and Swedish expeditions were partially funded by the Knut and Alice Wallenberg Foundation (grant no. 2022.0096) and the Swedish Research Council VR (grant no. 2020-00457) to I.R.S., and L.S.L. was supported by the Independent Research Fund Denmark to B.T. (grant no. 1127-00362B).",

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doi = "10.1038/s41467-026-71116-5",

language = "English",

volume = "17",

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TY - JOUR

T1 - Long-term nitrogen burial exceeds denitrification in global fjords

AU - Cheung, Henry L. S.

AU - Levin, Lubrina S.

AU - Smeaton, Craig

AU - Politi, Tobia

AU - Thamdrup, Bo

AU - Santos, Isaac R.

AU - Bonaglia, Stefano

N1 - Funding: Research funding was provided by the Swedish Research Council VR to S.B. (grant no. 2022-04710). The Iceland and Swedish expeditions were partially funded by the Knut and Alice Wallenberg Foundation (grant no. 2022.0096) and the Swedish Research Council VR (grant no. 2020-00457) to I.R.S., and L.S.L. was supported by the Independent Research Fund Denmark to B.T. (grant no. 1127-00362B).

PY - 2026/4/1

Y1 - 2026/4/1

N2 - Nitrogen (N) availability regulates primary productivity and hence directly affects global oceanic carbon sequestration. Global fjords account for up to 11% of marine carbon burial. However, N loss via sediment burial remains largely unquantified. Here, we show that global fjords are hotspots of N burial, accounting for up to 18% of oceanic N burial despite only covering 0.1% of the ocean area. Burial is the dominant N loss mechanism, exceeding microbial N loss via denitrification and anammox, which are generally considered the major N loss mechanisms. Microbial N loss dominates in anoxic fjords and appears to be a function of temperature and nutrient availability. Overall, fjords efficiently sequester excess N in sediments over long time scales. Accelerated warming will promote both N burial from increased primary production and microbial N loss from warmer temperatures, affecting N budgets in fjords and in the ocean in general.

AB - Nitrogen (N) availability regulates primary productivity and hence directly affects global oceanic carbon sequestration. Global fjords account for up to 11% of marine carbon burial. However, N loss via sediment burial remains largely unquantified. Here, we show that global fjords are hotspots of N burial, accounting for up to 18% of oceanic N burial despite only covering 0.1% of the ocean area. Burial is the dominant N loss mechanism, exceeding microbial N loss via denitrification and anammox, which are generally considered the major N loss mechanisms. Microbial N loss dominates in anoxic fjords and appears to be a function of temperature and nutrient availability. Overall, fjords efficiently sequester excess N in sediments over long time scales. Accelerated warming will promote both N burial from increased primary production and microbial N loss from warmer temperatures, affecting N budgets in fjords and in the ocean in general.

KW - Fjords

KW - Nitrogen

KW - Loss

KW - Sediment

KW - Water column

KW - Seabed

KW - Coastal

KW - O2 depletion

KW - Oxygen

KW - Burial

U2 - 10.1038/s41467-026-71116-5

DO - 10.1038/s41467-026-71116-5

M3 - Article

SN - 2041-1723

VL - 17

JO - Nature Communications

JF - Nature Communications

M1 - 3148

ER -

Long-term nitrogen burial exceeds denitrification in global fjords

Abstract

UN SDGs

Keywords

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Dataset and Markdown codes for article "Long-term nitrogen burial exceeds denitrification in global fjords"

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