Coupled Manganese Redox Cycling and Organic Carbon Degradation on Mineral Surfaces

Ma, Dong; Wu, Juan; Yang, Peng; Zhu, Mengqiang

doi:10.1021/acs.est.0c02065

Cited by 77 publications

(78 citation statements)

References 76 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Metallic colloids in soil may be formed by biomineralization during soil reduction or precipitation in the root zone and potentially incorporate toxic trace elements like Hg (Weber et al, 2009;Manceau et al, 2008). These colloids may increase the mobility and persistence of toxic trace metals in soil solution if they do not aggregate to bigger particles.…”

Section: Introductionmentioning

confidence: 99%

Mercury mobility, colloid formation and methylation in a polluted Fluvisol as affected by manure application and flooding–draining cycle

et al. 2021

View full text Add to dashboard Cite

Abstract. Floodplain soils polluted with high levels of mercury (Hg) are potential point sources to downstream ecosystems. Repeated flooding (e.g., redox cycling) and agricultural activities (e.g., organic matter addition) may influence the fate and speciation of Hg in these soil systems. The formation and aggregation of colloids and particles influence both Hg mobility and its bioavailability to microbes that form methylmercury (MeHg). In this study, we conducted a microcosm flooding–draining experiment on Hg-polluted floodplain soils originating from an agriculturally used area situated in the Rhone Valley (Valais, Switzerland). The experiment comprised two 14 d flooding periods separated by one 14 d draining period. The effect of freshly added natural organic matter on Hg dynamics was assessed by adding liquid cow manure (+MNR) to two soils characterized by different Hg (47.3±0.5 or 2.38±0.01 mg kg−1) and organic carbon (OC: 1.92 wt % or 3.45 wt %) contents. During the experiment, the release, colloid formation of Hg in soil solution and net MeHg production in the soil were monitored. Upon manure addition in the highly polluted soil (lower OC), an accelerated release of Hg to the soil solution could be linked to a fast reductive dissolution of Mn oxides. The manure treatments showed a fast sequestration of Hg and a higher percentage of Hg bound by particulate (0.02–10 µm). Also, analyses of soil solutions by asymmetrical flow field-flow fractionation coupled with inductively coupled plasma mass spectrometry (AF4–ICP–MS) revealed a relative increase in colloidal Hg bound to dissolved organic matter (Hg–DOM) and inorganic colloidal Hg (70 %–100 %) upon manure addition. Our experiment shows a net MeHg production the first flooding and draining period and a subsequent decrease in absolute MeHg concentrations after the second flooding period. Manure addition did not change net MeHg production significantly in the incubated soils. The results of this study suggest that manure addition may promote Hg sequestration by Hg complexation on large organic matter components and the formation and aggregation of inorganic HgS(s) colloids in Hg-polluted Fluvisols with low levels of natural organic matter.

show abstract

Section: Introductionmentioning

confidence: 99%

Mercury mobility, colloid formation and methylation in a polluted Fluvisol as affected by manure application and flooding–draining cycle

et al. 2021

View full text Add to dashboard Cite

show abstract

“…Low valency dissolved Fe and Mn in soil can be generated through several processes. ( 1) With large amounts of organic matter (to donate electrons) present, abiotic reduction and dissimilatory microbial reduction of Fe(III) and Mn(III,IV) oxides can occur and promote Fe and Mn mobility [51]. (2) The abiotic reductive dissolution reaction rate can be accelerated in the presence of ligand-reducing pairs [20].…”

Section: Soil Typementioning

confidence: 99%

“…(3) Light can markedly affect the Fe(III) reduction rate [53] and may contribute to Fe(III) reduction at the soil surface. ( 4) Under aerobic conditions, the presence of organic matter can greatly decrease the rate and degree of Mn(II) oxidation by oxygen that occurs on goethite surfaces [51]. Favorable environmental conditions and the various mechanisms through which Fe and Mn can be released mean that dissolved Fe and Mn in soil can enter groundwater through the infiltration of precipitation.…”

Section: Soil Typementioning

confidence: 99%

Elevated Fe and Mn Concentrations in Groundwater in the Songnen Plain, Northeast China, and the Factors and Mechanisms Involved

et al. 2021

View full text Add to dashboard Cite

Groundwater is an essential source of drinking and irrigation water. However, elevated Fe and Mn concentrations in groundwater have been found in recent decades, which can adversely affect human health and decrease crop quality and yields. The roles of hydrogeochemical changes and groundwater pollution (exogenous reductive material inputs) in this have not been studied adequately. We determined the distribution of Fe and Mn concentrations in groundwater in the Songnen Plain, northeast China, which is known for elevated Fe and Mn concentrations, and investigated the factors and mechanisms involved in causing the elevated concentrations. Chemical and statistical analyses indicated that the Fe and Mn concentrations in groundwater significantly correlated with climate parameters (precipitation and temperature), surface features (altitude, distance from a river, soil type, soil texture, and land use type) and hydrogeochemical characteristics (chemical oxygen demand and NH4+, NO3−, and P concentrations). In particular, the Fe and Mn concentrations in groundwater are higher in areas containing paddy fields and water bodies than other land use type areas. Areas with groundwater containing ultra-high Fe and Mn concentrations have almost all of the favorable factors. The main reasons for the elevated Fe and Mn concentrations in groundwater in the study area are the Fe/Mn mineral-rich strata and soil with abundant organic matter acting as sources of Fe and Mn to the groundwater and the reductive environment in the lower terrain and areas containing water bodies favoring Fe and Mn dissolution in the groundwater. Inputs of pollutants from agricultural activities have caused the Fe and Mn concentrations in groundwater to increase. Future studies should be performed to study interactions between pollutants from agricultural activities and Fe and Mn in groundwater and develop environmental management strategies for preventing future increases in Fe and Mn concentrations and promoting sustainable development of agriculture.

show abstract

“…Both iron (Fe) and manganese (Mn) are key to the biogeochemical cycling of carbon (C), nutrients, and trace elements in soils (Borch et al 2009;Henderson et al 2012;Herndon et al 2017;Ma et al 2020). When soil O2 concentrations are low, many soil bacteria readily switch to Mn and Fe as alternate terminal electron acceptors for respiration (Lovley and Phillips 1988;Pett-Ridge et al 2006;DeAngelis et al 2010).…”

Section: Introductionmentioning

confidence: 99%

Using Fixed-Potential Electrodes To Quantify Iron And Manganese Redox Cycling In Upland Soils

Hodges

Regan

Forsythe

et al. 2022

Preprint

View full text Add to dashboard Cite

Changes in metal redox in soils can exert strong controls on carbon mineralization but are difficult to measure in real time. Recently, potentiostatically poised electrodes (fixed-potential electrodes) have been demonstrated as promising for measuring the rate of oxidation and reduction at a specific reduction potential in situ in riparian soils but are yet untested in upland soils. Here for the first time, we explored the fine-scale temporal fluctuations of redox of both iron and manganese in response to environmental conditions. We used three-electrode systems with working electrodes fixed at 100 mV (vs. SHE) in 2019 and added 400 mV in 2020 at 50 cm and 70 cm in the valley floor soil of a headwater watershed at the Susquehanna Shale Hills Critical Zone Observatory (SSHCZO). Electrodes fixed at 100 mV mimic iron oxides and at 400 mV mimic manganese oxides, and real-time reduction and oxidation rates can be calculated from measured changes in the electric current over time. Alongside the electrodes, soil porewater chemistry, pCO2, pO2, groundwater level, and precipitation were measured. Results indicate that fixed-potential electrodes successfully detected temporally fine-scale fluctuations in metal redox state, which was confirmed by the coordinated datasets. Water table fluctuations at the electrode depth drove metal reduction, and rainfall events stimulated oxidation reactions in the vadose zone. For the first time in soils, we directly measured the frequency, period, and amplitude of oxidation and reduction events. All of these are key variables that control the biogeochemical impact of metal oxide redox in terrestrial systems. At the SSHCZO we observed multi-day reduction or oxidation events with a return interval of 5 – 10 days, controlled by precipitation frequency. Such measurements with fixed-potential electrodes hold promise for accurately exploring the fast-changing biogeochemical impacts of metal redox in upland soils where such reactions have been difficult to quantify.

show abstract

Coupled Manganese Redox Cycling and Organic Carbon Degradation on Mineral Surfaces

Cited by 77 publications

References 76 publications

Mercury mobility, colloid formation and methylation in a polluted Fluvisol as affected by manure application and flooding–draining cycle

Mercury mobility, colloid formation and methylation in a polluted Fluvisol as affected by manure application and flooding–draining cycle

Elevated Fe and Mn Concentrations in Groundwater in the Songnen Plain, Northeast China, and the Factors and Mechanisms Involved

Using Fixed-Potential Electrodes To Quantify Iron And Manganese Redox Cycling In Upland Soils

Contact Info

Product

Resources

About