Details
| Original language | English |
|---|---|
| Article number | e2025GB008709 |
| Journal | Global biogeochemical cycles |
| Volume | 40 |
| Issue number | 1 |
| Publication status | Published - 1 Jan 2026 |
Abstract
Fe(III) (oxyhydr)oxides are well-known for their role in organic carbon (OC) stabilization in terrestrial soils. Coastal and estuarine soils typically act as iron sinks and receive a high input of OC. However, tidal submersion induces anoxic and reducing conditions that favor the microbial reductive dissolution of Fe(III) (oxyhydr)oxides, followed by the partial formation of Fe(II) minerals. However, the potential of these minerals—such as siderite, vivianite and iron sulfides—to stabilize C has only recently received attention. In this review, we (a) elucidate methodological constraints in Fe(II) mineral analysis, (b) highlight formation mechanisms of Fe(II) minerals and (c) their interactions with organic matter (OM) and inorganic C and (d) explore their role in C stabilization. Fe(II) minerals interact with OM through surface complexation, coprecipitation or physical entrapment, despite their typically low surface charge. These interactions are facilitated by surface-reactive chemical species such as potential-determining ions, divalent cations and functional surface groups, enabling Fe(II) minerals to bind or occlude OC in anoxic settings. During Fe(II) mineral formation, dissolved inorganic C can be exported as total alkalinity or precipitated as stable carbonates, both contributing to long-term inorganic C sequestration. Emerging research indicates that Fe(II) mineral interactions with organic and inorganic C likely binds 5.8–16.6 Tg C yr−1, a potential overlooked global C sink with yet unexplored long-term stability. This review thus emphasizes the geochemical relevance of Fe(II) minerals beyond transient redox products as they may constitute a persistent and quantifiable carbon sink in anoxic sediments, warranting further exploration.
Keywords
- anoxic soils, blue carbon, Fe(II) minerals, iron-organic matter interactions, pyrite, siderite
ASJC Scopus subject areas
- Environmental Science(all)
- Global and Planetary Change
- Environmental Science(all)
- Environmental Chemistry
- Environmental Science(all)
- General Environmental Science
- Earth and Planetary Sciences(all)
- Atmospheric Science
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In: Global biogeochemical cycles, Vol. 40, No. 1, e2025GB008709, 01.01.2026.
Research output: Contribution to journal › Review article › Research › peer review
}
TY - JOUR
T1 - The Role of Fe(II) Minerals in Carbon Stabilization in Coastal and Estuarine Anoxic Environments
AU - Jagode, Jan
AU - Carstens, Jannis Florian
AU - Guggenberger, Georg
N1 - Publisher Copyright: © 2026. The Author(s).
PY - 2026/1/1
Y1 - 2026/1/1
N2 - Fe(III) (oxyhydr)oxides are well-known for their role in organic carbon (OC) stabilization in terrestrial soils. Coastal and estuarine soils typically act as iron sinks and receive a high input of OC. However, tidal submersion induces anoxic and reducing conditions that favor the microbial reductive dissolution of Fe(III) (oxyhydr)oxides, followed by the partial formation of Fe(II) minerals. However, the potential of these minerals—such as siderite, vivianite and iron sulfides—to stabilize C has only recently received attention. In this review, we (a) elucidate methodological constraints in Fe(II) mineral analysis, (b) highlight formation mechanisms of Fe(II) minerals and (c) their interactions with organic matter (OM) and inorganic C and (d) explore their role in C stabilization. Fe(II) minerals interact with OM through surface complexation, coprecipitation or physical entrapment, despite their typically low surface charge. These interactions are facilitated by surface-reactive chemical species such as potential-determining ions, divalent cations and functional surface groups, enabling Fe(II) minerals to bind or occlude OC in anoxic settings. During Fe(II) mineral formation, dissolved inorganic C can be exported as total alkalinity or precipitated as stable carbonates, both contributing to long-term inorganic C sequestration. Emerging research indicates that Fe(II) mineral interactions with organic and inorganic C likely binds 5.8–16.6 Tg C yr−1, a potential overlooked global C sink with yet unexplored long-term stability. This review thus emphasizes the geochemical relevance of Fe(II) minerals beyond transient redox products as they may constitute a persistent and quantifiable carbon sink in anoxic sediments, warranting further exploration.
AB - Fe(III) (oxyhydr)oxides are well-known for their role in organic carbon (OC) stabilization in terrestrial soils. Coastal and estuarine soils typically act as iron sinks and receive a high input of OC. However, tidal submersion induces anoxic and reducing conditions that favor the microbial reductive dissolution of Fe(III) (oxyhydr)oxides, followed by the partial formation of Fe(II) minerals. However, the potential of these minerals—such as siderite, vivianite and iron sulfides—to stabilize C has only recently received attention. In this review, we (a) elucidate methodological constraints in Fe(II) mineral analysis, (b) highlight formation mechanisms of Fe(II) minerals and (c) their interactions with organic matter (OM) and inorganic C and (d) explore their role in C stabilization. Fe(II) minerals interact with OM through surface complexation, coprecipitation or physical entrapment, despite their typically low surface charge. These interactions are facilitated by surface-reactive chemical species such as potential-determining ions, divalent cations and functional surface groups, enabling Fe(II) minerals to bind or occlude OC in anoxic settings. During Fe(II) mineral formation, dissolved inorganic C can be exported as total alkalinity or precipitated as stable carbonates, both contributing to long-term inorganic C sequestration. Emerging research indicates that Fe(II) mineral interactions with organic and inorganic C likely binds 5.8–16.6 Tg C yr−1, a potential overlooked global C sink with yet unexplored long-term stability. This review thus emphasizes the geochemical relevance of Fe(II) minerals beyond transient redox products as they may constitute a persistent and quantifiable carbon sink in anoxic sediments, warranting further exploration.
KW - anoxic soils
KW - blue carbon
KW - Fe(II) minerals
KW - iron-organic matter interactions
KW - pyrite
KW - siderite
UR - http://www.scopus.com/inward/record.url?scp=105026380013&partnerID=8YFLogxK
U2 - 10.1029/2025GB008709
DO - 10.1029/2025GB008709
M3 - Review article
AN - SCOPUS:105026380013
VL - 40
JO - Global biogeochemical cycles
JF - Global biogeochemical cycles
SN - 0886-6236
IS - 1
M1 - e2025GB008709
ER -