Stable iron isotope signals indicate a “pseudo-abiotic” process driving deep iron release in methanic sediments

Henkel, Susann; Liu, Bo; Staubwasser, Michael; Kasemann, Simone A.; Meixner, Anette; Aromokeye, David A.; Friedrich, Michael W.; Kasten, Sabine

doi:https://doi.org/10.5194/bg-22-1673-2025

Articles | Volume 22, issue 6

https://doi.org/10.5194/bg-22-1673-2025

© Author(s) 2025. This work is distributed under
the Creative Commons Attribution 4.0 License.

https://doi.org/10.5194/bg-22-1673-2025

© Author(s) 2025. This work is distributed under
the Creative Commons Attribution 4.0 License.

Articles | Volume 22, issue 6

Research article

|

31 Mar 2025

Research article |

| 31 Mar 2025

Stable iron isotope signals indicate a “pseudo-abiotic” process driving deep iron release in methanic sediments

Susann Henkel, Bo Liu, Michael Staubwasser, Simone A. Kasemann, Anette Meixner, David A. Aromokeye, Michael W. Friedrich, and Sabine Kasten

Supplement

https://doi.org/10.5194/bg-22-1673-2025-supplement

Data sets

Radiographs of the gravity core HE443/10-3 from North Sea [dataset] S. Henkel et al. https://doi.org/10.1594/PANGAEA.971531

Pore-water and solid-phase data of a multicorer core and a gravity core at Station HE443/10, North Sea [dataset bundled publication] S. Henkel et al. https://doi.org/10.1594/PANGAEA.971490

Solid phase geochemistry of sediment core HE443/10-3 D. A. Aromokeye et al. https://doi.org/10.1594/PANGAEA.893760

Pore water geochemistry of sediment core HE443/10-3 D. A. Aromokeye et al. https://doi.org/10.1594/PANGAEA.893766

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Short summary

We intend to unravel iron (Fe) reduction pathways in high-deposition methanic sediments because pools of Fe minerals could stimulate methane oxidation and also generation. Our data from the North Sea show that Fe release takes place mechanistically differently to Fe reduction in shallow sediments, which typically fractionates Fe isotopes. We conclude that fermentation of organic matter involving interspecies electron transfer, partly through conductive Fe oxides, could play an important role.