Rhizogenic Fe-C redox cycling: A hypothetical biogeochemical mechanism that drives crustal weathering in upland soils
Field-scale observations of two upland soils derived from contrasting granite and basalt bedrocks are presented to hypothesize that redox activity of rhizospheres exerts substantial effects on mineral dissolution and colloidal translocation in many upland soils. Rhizospheres are redox-active microsites and in the absence of O2, oxidation of rhizodeposits can be coupled by reduction of redox-active species such as Fe, a biogenic reduction that leads to Fe translocation and oxidation, accompanied by substantial proton flux. Not only do rhizogenic Fe-C redox cycles demonstrate a process by which the rhizosphere affects an environment well outside the near-root zone, but these redox processes are also hypothesized to be potent weathering systems, such that rhizogenic redox-reactions complement acid- and ligand-promoted reactions as major biogeochemical processes that control crustal weathering. The potential significance of Fe-C redox cycling is underscored by the deep and extensive rooting and mottling of upland subsoils across a wide range of plant communities, lithologies, and soil-moisture and temperature regimes. © 2008 Springer Science+Business Media B.V.
Duke Scholars
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Related Subject Headings
- Agronomy & Agriculture
- 4104 Environmental management
- 3703 Geochemistry
- 0502 Environmental Science and Management
- 0402 Geochemistry
- 0399 Other Chemical Sciences
Citation
Published In
DOI
EISSN
ISSN
Publication Date
Volume
Issue
Start / End Page
Related Subject Headings
- Agronomy & Agriculture
- 4104 Environmental management
- 3703 Geochemistry
- 0502 Environmental Science and Management
- 0402 Geochemistry
- 0399 Other Chemical Sciences