Manganese Oxides Incubated in Acidic Forest Soil Retain More Organic Carbon Than Iron Oxides.
8 affiliations
- 1Environmental Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee37831, United States.
- 2Department of Earth and Planetary Sciences, University of Tennessee, Knoxville, Tennessee37996, United States.
- 3Department of Crop and Soil Sciences, North Carolina State University, Raleigh, North Carolina27695, United States.
- 4USDA-NRCS-National Soil Survey Center, Lincoln, Nebraska68508, United States.
- 5X-ray Science Division, Argonne National Laboratory, Lemont, Illinois60439, United States.
- 6Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee37831, United States.
- 7Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Richland, Washington99354, United States.
- 8National Synchrotron Light Source II, Brookhaven National Laboratory, Upton, New York11973, United States.
Abstract
Iron (oxyhydr)oxides are well-recognized contributors to soil carbon (C) storage, but the effects of manganese oxides on carbon storage and transformation are relatively unexplored. Here, the relative capacities of Fe and Mn oxides to bind and stabilize soil organic C were directly compared using an in situ incubation experiment. Quartz sands coated with either poorly crystalline Mn(III/IV) oxides or Fe(III) oxides, or left uncoated, were buried in a temperate forest soil for up to one year. Chemical extractions, X-ray absorption and photon spectroscopies, scanning electron microscopy, and neutron scattering were used to evaluate organic and mineral associations and transformations during the incubation. At the end of the 1-year study, Mn oxide stored ∼11× more carbon (42.0 ± 14.3 mg C/m2 oxide) than Fe oxide (3.72 ± 0.37 mg C/m2 oxide) per unit surface area. Manganese oxidation state changed over time, likely reflecting reactions between organic C and Mn oxide, while Fe oxidation state remained unaltered. Total organic C that was associated with Mn oxide was relatively enriched in carboxylic and O-alkyl-C compared to Fe oxides and quartz, either due to preferential sorption or oxidation on the mineral surface. Mn oxides also sorbed high amounts of Ca despite being incubated in an acidic, base-cation depleted soil, which potentially facilitated C sorption. Our study demonstrates that Mn oxides, with the assistance of Ca-bridging, have a greater potential to stabilize organic C than Fe oxides in acidic environments despite higher reactivity.
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BibTeX
@article{bidas2026manganese,
title = {{Manganese Oxides Incubated in Acidic Forest Soil Retain More Organic Carbon Than Iron Oxides.}},
author = {Kristen Bidas and Hui Li and Fernanda Santos and Erin C Rooney and Benjamin Reinhart and Lilin He and Changwoo Do and Qian Zhao and Ryan Tappero and Elizabeth Herndon},
journal = {Environmental science \& technology},
year = {2026},
month = sep,
doi = {10.1021/acs.est.6c07327},
url = {https://europepmc.org/article/MED/42915431},
note = {CC BY},
}
RIS
TY - JOUR
TI - Manganese Oxides Incubated in Acidic Forest Soil Retain More Organic Carbon Than Iron Oxides.
AU - Kristen Bidas
AU - Hui Li
AU - Fernanda Santos
AU - Erin C Rooney
AU - Benjamin Reinhart
AU - Lilin He
AU - Changwoo Do
AU - Qian Zhao
AU - Ryan Tappero
AU - Elizabeth Herndon
PY - 2026
DA - 2026/09/01
JO - Environmental science & technology
DO - 10.1021/acs.est.6c07327
UR - https://europepmc.org/article/MED/42915431
AB - Iron (oxyhydr)oxides are well-recognized contributors to soil carbon (C) storage, but the effects of manganese oxides on carbon storage and transformation are relatively unexplored. Here, the relative capacities of Fe and Mn oxides to bind and stabilize soil organic C were directly compared using an in situ incubation experiment. Quartz sands coated with either poorly crystalline Mn(III/IV) oxides or Fe(III) oxides, or left uncoated, were buried in a temperate forest soil for up to one year. Chemical extractions, X-ray absorption and photon spectroscopies, scanning electron microscopy, and neutron scattering were used to evaluate organic and mineral associations and transformations during the incubation. At the end of the 1-year study, Mn oxide stored ∼11× more carbon (42.0 ± 14.3 mg C/m2 oxide) than Fe oxide (3.72 ± 0.37 mg C/m2 oxide) per unit surface area. Manganese oxidation state changed over time, likely reflecting reactions between organic C and Mn oxide, while Fe oxidation state remained unaltered. Total organic C that was associated with Mn oxide was relatively enriched in carboxylic and O-alkyl-C compared to Fe oxides and quartz, either due to preferential sorption or oxidation on the mineral surface. Mn oxides also sorbed high amounts of Ca despite being incubated in an acidic, base-cation depleted soil, which potentially facilitated C sorption. Our study demonstrates that Mn oxides, with the assistance of Ca-bridging, have a greater potential to stabilize organic C than Fe oxides in acidic environments despite higher reactivity.
SN - 0013-936X
SN - 1520-5851
ER -