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Updated: May 10, 2026
06:52
Experimental Column Setup for Studying Anaerobic Biogeochemical Interactions Between Iron (Oxy)Hydroxides, Trace Elements, and Bacteria
Published on: December 19, 2017
Iron traps terrestrially derived dissolved organic matter at redox interfaces
Thomas Riedel1, Dominik Zak, Harald Biester
1Institut für Geoökologie, Technische Universität Braunschweig, 38106 Braunschweig, Germany. thomas.riedel@tu-bs.de
Summary
Iron precipitation in peatlands selectively removes plant-derived organic compounds from dissolved organic matter (DOM). Redox interfaces act as barriers, limiting DOM flux to oceans.
Area of Science:
- Environmental Chemistry
- Biogeochemistry
- Soil Science
Background:
- Reactive iron and organic carbon are closely linked in soils and sediments.
- Molecular-level characterization of organic compounds associated with iron remains limited.
- Peatland redox interfaces offer a unique system to study coupled iron and dissolved organic matter (DOM) biogeochemical cycles.
Purpose of the Study:
- To investigate the molecular composition of DOM removed by iron precipitation at peatland redox interfaces.
- To understand the role of redox interfaces in controlling DOM flux.
Main Methods:
- Aeration of anoxic fen pore waters to induce iron hydroxide precipitation.
- Ultra-high-resolution mass spectrometry (MS) to characterize DOM.
- Quantification of dissolved iron and dissolved organic carbon removal.
Main Results:
- Iron hydroxide precipitation rapidly removed >90% of dissolved iron and 27% of dissolved organic carbon (DOM).
- Vascular plant-derived aromatic and pyrogenic compounds were preferentially retained during iron precipitation.
- Carboxyl-rich aliphatic acids largely remained in solution.
Conclusions:
- Redox interfaces are selective barriers that influence the composition of DOM.
- These interfaces limit the transport of land-derived DOM to oceanic waters.
- Understanding these processes is crucial for global carbon cycling.
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