A contribution of molecular modeling to supramolecular structures in soil organic matter# DOI
Martin H. Gerzabek, Adélia J. A. Aquino,

Yerko Ignacio Escalona Balboa

et al.

Journal of Plant Nutrition and Soil Science, Journal Year: 2022, Volume and Issue: 185(1), P. 44 - 59

Published: Jan. 22, 2022

Abstract Background Knowledge of the stabilizing mechanisms soil organic matter (SOM) is extremely important for numerous functions. For this, insight into nature through appropriate model concepts are crucial. Aims several years, a heated debate has emerged on transformation and stabilization SOM. In present work, we try to contribute this using molecular modeling providing comprehensive overview history application tools developing structural Methods Molecular methods based quantum and/or classical mechanics were used SOM related properties including interactions with reactive surfaces minerals. Results Modeling aggregates revealed that hydrogen bonds cation bridges main factors in solution, whereas pH modifies stability. The modeled supramolecular exhibit physicochemical properties, similar those humic substances (HS) described literature. HS models kaolinite nanopores led partial disintegration individual molecules smaller subaggregates. Conclusions From point view, microaggregate stable solution. However, their binding mineral constituents can be also form or Thus, stability relative, depending interacting environment. This reconciles two points view HS: either as small structures.

Language: Английский

Influence of Organic Ligands on the Redox Properties of Fe(II) as Determined by Mediated Electrochemical Oxidation DOI
Jeffrey M. Hudson, George W. Luther, Yu‐Ping Chin

et al.

Environmental Science & Technology, Journal Year: 2022, Volume and Issue: 56(12), P. 9123 - 9132

Published: June 8, 2022

Fe(II) has been extensively studied due to its importance as a reductant in biogeochemical processes and contaminant attenuation. Previous studies have shown that ligands can alter aqueous redox reactivity but their data interpretation is constrained by the use of probe compounds. Here, we employed mediated electrochemical oxidation (MEO) an approach directly quantify extent absence presence three model organic (citrate, nitrilotriacetic acid, ferrozine) across range potentials (EH) pH, thereby manipulating over broad fixed thermodynamic conditions. Fe(III)-stabilizing enhanced thermodynamically unfavorable regions (i.e., low pH EH) while stabilizing ligand (ferrozine) prevented all regions. We experimentally derived apparent standard potentials, EHϕ, for these other (oxalate, oxalate2, NTA2, EDTA, OH2) Fe-ligand couples via oxidative current integration. Preferential stabilization Fe(III) decreased EHϕ values, Nernstian correlation between log(KFe(III)/KFe(II)) exists wide stability constants. used this estimate natural matter isolate, demonstrating MEO be measure iron constant ratios unknown ligands.

Language: Английский

Citations

36
Oxygen Limitation Accelerates Regeneration of Active Sites on a MnO2 Surface: Promoting Transformation of Organic Matter and Carbon Preservation DOI
Zhiqiang Wang, Hanzhong Jia, H. Zhao

et al.

Environmental Science & Technology, Journal Year: 2022, Volume and Issue: 56(13), P. 9806 - 9815

Published: June 20, 2022

Birnessite (δ-MnO2) is a layered manganese oxide widely present in the environment and actively participates transformation of natural organic matter (NOM) biogeochemical processes. However, effect oxygen on dynamic interface processes NOM δ-MnO2 remains unclear. This study systematically investigated interactions between fulvic acid (FA) under both aerobic anaerobic conditions. FA was transformed by via direct electron transfer generated reactive species (ROS). During 32-day reaction, 79.8% total carbon (TOC) solution removed conditions, unexpectedly higher than that conditions (69.8%), suggesting limitation more conducive to oxidative δ-MnO2. The vacancies (OV) surface were exposed thus promoting adsorption as well regeneration active sites. Additionally, reaction with weakened strongly bonded lattice (Olatt), released Olatt an important source ROS. Interestingly, part (OC) preserved forming MnCO3, which might be novel mechanism for preservation. These findings contribute improved understanding MnO2 provide new insights into effects cycling preservation OC.

Language: Английский

Citations

31
Minerals: A missing role for enhanced biochar carbon sequestration from the thermal conversion of biomass to the application in soil DOI
Hongyan Nan, Ondřej Mašek, Fan Yang

et al.

Earth-Science Reviews, Journal Year: 2022, Volume and Issue: 234, P. 104215 - 104215

Published: Oct. 13, 2022

Language: Английский

Citations

30
Methylmercury Degradation by Trivalent Manganese DOI
Shuang Zhang, Baohui Li, Yi Chen

et al.

Environmental Science & Technology, Journal Year: 2023, Volume and Issue: 57(14), P. 5988 - 5998

Published: March 30, 2023

Methylmercury (MeHg) is a potent neurotoxin and has great adverse health impacts on humans. Organisms sunlight-mediated demethylation are well-known detoxification pathways of MeHg, yet whether abiotic environmental components contribute to MeHg degradation remains poorly known. Here, we report that can be degraded by trivalent manganese (Mn(III)), naturally occurring widespread oxidant. We found 28 ± 4% could Mn(III) located synthesized Mn dioxide (MnO2–x) surfaces during the reaction 0.91 μg·L–1 5 g·L–1 mineral at an initial pH 6.0 for 12 h in 10 mM NaNO3 25 °C. The presence low-molecular-weight organic acids (e.g., oxalate citrate) substantially enhances MnO2–x via formation soluble Mn(III)-ligand complexes, leading cleavage carbon–Hg bond. also reactions with Mn(III)-pyrophosphate apparent rate constants comparable those biotic photolytic degradation. Thiol ligands (cysteine glutathione) show negligible effects Mn(III). This research demonstrates potential roles degrading natural environments, which may further explored remediating heavily polluted soils engineered systems containing MeHg.

Language: Английский

Citations

21
Manganese effects on plant residue decomposition and carbon distribution in soil fractions depend on soil nitrogen availability DOI Creative Commons
Avishesh Neupane, Elizabeth Herndon, Thea Whitman

et al.

Soil Biology and Biochemistry, Journal Year: 2023, Volume and Issue: 178, P. 108964 - 108964

Published: Jan. 23, 2023

Language: Английский

Citations

19
Reactive iron, not fungal community, drives organic carbon oxidation potential in floodplain soils DOI Creative Commons
Hannah Naughton, Bradley B. Tolar, Christian Dewey

et al.

Soil Biology and Biochemistry, Journal Year: 2023, Volume and Issue: 178, P. 108962 - 108962

Published: Jan. 19, 2023

Wetlands host ∼20% of terrestrial organic carbon and serve as a major sink for atmospheric carbon. Anoxic soils sediments accrue soil (SOC) partly by hampering the activity extracellular oxidative enzymes that break down phenolic polymers. Upon aeration, fungal-driven enzymatic depolymerization microbial respiration released monomers ensue. Redox-active metals can simultaneously catalyze abiotic nonspecific oxidation SOC, notable examples including Mn(III) or Fe(II) through Fenton-like, hydrogen peroxide-catalyzed radical production. However, extent reactive metal contributions to biotic SOC degradation is not understood in context natural environments with diverse redox chemistry. We tested relative fungi, substrate (L-DOPA) floodplain representing range transient conditions driven permanent vs. periodic flooding. Phenol potential was highest permanently flooded fewer fungal taxa known observed (per)oxidase instead correlated HCl-extractable Fe(II), Fe(total) Fe(II)/Fe(total), suggesting specific role Fe(II). additions enhanced phenol sterilized non-sterilized presence peroxide, indicating Fe-mediated chemistry could significantly enhance wetland throughout redox-active soils. Fungal community composition did correlate overall only more oxic adjacent river communities showed declining after sterilization. addition across all soils, although it appeared drive fungal-mediated most aerated Understanding how mediate oxidants microbially-harnessed enzyme cofactors substrates under variable hydrologic controls will improve our ability represent models other frequently saturated

Language: Английский

Citations

19
Disentangling the effects of mineral fertiliser N, P and K on microbial biomass, necromass and ionome in soil from the Askov long-term field experiment DOI Creative Commons
Sanja Annabell Schwalb, Michael Hemkemeyer, Bent T. Christensen

et al.

Soil Biology and Biochemistry, Journal Year: 2024, Volume and Issue: 195, P. 109449 - 109449

Published: April 27, 2024

Given the increasingly recognised importance of microbial biomass (MB) in soil organic carbon (SOC) sequestration, knowledge ionome beyond (C), nitrogen (N) and phosphorus (P) becomes crucial. The could indicate nutritional restrictions related to MB growth necromass C (MN-C) accumulation. In this study, soils receiving different combinations mineral N, P potassium (K) were sampled Askov long-term field experiment, Denmark, analysed for elemental composition including P, K, magnesium (Mg), manganese (Mn) zinc (Zn) using fumigation-extraction ICP-OES. Furthermore, bacterial, archaeal fungal gene abundance was determined by qPCR as community shifts may relate shifts. MN-C amino sugar analysis. MB-C unaffected fertiliser treatments not correlated with MN-C. N fertilisation increased K additions plant-derived SOC, indicating SOC Availability MB-P MB-K, respectively, reduced MB-C:P ratio but MB-C:K. pH Mn availability which MB-Mn MB-C:Mn. ITS1 copies responded positively availability. A MB-C:Mn associated a relative increase copy abundance. This linked an positive link between availability, level, yet reflected accumulation, accumulation possibly due plant turnover.

Language: Английский

Citations

6
Changing sub-Arctic tundra vegetation upon permafrost degradation: impact on foliar mineral element cycling DOI Creative Commons

Elisabeth Mauclet,

Yannick Agnan, Catherine Hirst

et al.

Biogeosciences, Journal Year: 2022, Volume and Issue: 19(9), P. 2333 - 2351

Published: May 5, 2022

Abstract. Arctic warming and permafrost degradation are modifying northern ecosystems through changes in microtopography, soil water dynamics, nutrient availability, vegetation succession. Upon degradation, the release of deep stores nutrients, such as nitrogen phosphorus, from newly thawed stimulates production. More specifically, wetter lowlands show an increase sedges (as part graminoids), whereas drier uplands favor shrub expansion. These shifts composition may influence local mineral element cycling litter In this study, we evaluate on foliar stocks potential annual fluxes upon litterfall. We measured elemental (Al, Ca, Fe, K, Mn, P, S, Si, Zn) ∼ 500 samples typical tundra plant species two contrasting Alaskan sites, i.e., experimental sedge-dominated site (Carbon Permafrost Experimental Heating Research, CiPEHR) natural shrub-dominated (Gradient). The concentration these elements was specific, with sedge leaves having relatively high Si Ca Mn concentrations. Therefore, biomass response to thaw expected be main factors that dictate maximum observed litterfall fluxes, increasing expansion sites (CiPEHR), Consequently, expect will lead therefore affect across sub-Arctic implications for further

Language: Английский

Citations

23
Association between soil organic carbon and calcium in acidic grassland soils from Point Reyes National Seashore, CA DOI Creative Commons
Mike C. Rowley, Peter Nico, Sharon Bone

et al.

Biogeochemistry, Journal Year: 2023, Volume and Issue: 165(1), P. 91 - 111

Published: July 7, 2023

Organo-mineral and organo-metal associations play an important role in the retention accumulation of soil organic carbon (SOC). Recent studies have demonstrated a positive correlation between calcium (Ca) SOC content range types. However, most these focused on soils that contain carbonate (pH > 6). To assess importance Ca-SOC lower pH soils, we investigated their physical chemical interaction grassland Point Reyes National Seashore (CA, USA) at spatial scales. Multivariate analyses our bulk characterisation dataset showed strong exchangeable Ca (Ca

Language: Английский

Citations

16
Hematite-mediated Mn(II) abiotic oxidation under oxic conditions: pH effect and mineralization DOI
Shiwen Hu, Lirong Zheng, Hanyue Zhang

et al.

Journal of Colloid and Interface Science, Journal Year: 2023, Volume and Issue: 636, P. 267 - 278

Published: Jan. 7, 2023

Language: Английский

Citations

15