Redox Dynamics and the Persistence of Soil Organic Carbon across Environmental Gradients and Scales

Redox processes exert a fundamental control over the persistence of soil organic carbon (SOC). Fluctuations in oxygen availability regulate microbial metabolism and the reactivity of redox-sensitive minerals such as Fe and Mn oxides, together determining whether organic carbon is stabilized, transformed, or mineralized. Repeated oxidation–reduction cycles can both protect carbon through coprecipitation and sorption processes or promote its loss via reductive dissolution of Fe/Mn oxides, microbial respiration, and/or the Fe-catalyzed oxidation by hydrogen peroxide (Fenton reaction).

While redox dynamics have been traditionally investigated in wetland soils and sediments, growing evidence shows that redox transitions and microsites—zones where oxidizing and reducing reactions coexist—are also ubiquitous in well-drained upland soils, operating at micro- to millimeter scales within aggregates and the rhizosphere. Across this continuum, from permanently saturated to well-drained upland soils and sediments, redox processes shape the formation and dissolution of Fe/Mn oxides, influence microbial energy flow, and ultimately govern SOC persistence.

This Research Topic aims to deepen understanding of how redox fluctuations, microbial processes, and mineral transformations interact across these environmental gradients and spatial scales is critical to predict SOC stability and greenhouse-gas fluxes under a changing climate.

We welcome submissions addressing:

• The expression and impacts of redox processes across ecosystems — ranging from permanently anoxic wetlands and coastal sediments to well-drained upland soils where reducing and oxidizing microsites coexist

• The coupling of biogeochemical cycles of Fe, Mn, S, and C under fluctuating redox conditions


• The formation and dissolution of organo-mineral associations driven by redox oscillations

• Microbial metabolisms related to Fe, Mn and S reduction, methanogenesis, denitrification and their role in carbon stabilization or loss

• Modeling approaches linking microsite processes, soil profiles, and landscape-level carbon fluxes

• Innovative instrumental and analytical approaches for lab and field experiments in redox environments

• Implications of altered redox regimes for ecosystem functioning, carbon storage, and climate feedback under global climate change