Direct evidence for thickening nanoscale organic films at soil biogeochemical interfaces and its relevance to organic matter preservation

Environmental context Structural and conformational information on organic matter–clay complexes and whole soils was obtained using different NMR methods. The results show that organic matter interactions with clay mineral surfaces determine the accessibility of specific organic matter components at the soil–water interface. This physical conformation may also play a role in soil biogeochemical processes and binding to pollutants in terrestrial environments. Abstract Organic matter (OM)–mineral interactions play an important role in OM preservation, global carbon cycling and contaminant transport. Studies have indicated that preferential sorption of OM is dependent on mineral type and solution conditions. In this study, 1H high resolution–magic angle spinning nuclear magnetic resonance (HR-MAS NMR) spectroscopy was employed to examine OM chemistry in organo-clay complexes. Dissolved OM from a forest soil, Leonardite humic acid and Peat humic acid were sorbed to Ca2+ enriched kaolinite and montmorillonite. As observed using 1H HR-MAS NMR spectroscopy, kaolinite sorbed mainly long-chain aliphatic compounds such as those from plant cuticles whereas montmorillonite sorbed a mixture of aliphatic components and proteins. These results show the preferential sorption of specific dissolved OM components on clay surfaces. This was tested further using solid-state 13C and 1H HR-MAS NMR analysis of whole soils containing kaolinite and montmorillonite as well as a Peat soil for contrast. The species present at the soil–water interface were mainly aliphatic components, carbohydrates and amino acids. Aromatic constituents were present in the soils (observed by solid-state 13C NMR and by 1H HR-MAS NMR spectroscopy when a more penetrating solvent was used) which signifies that these compounds likely exist in more hydrophobic domains that are buried and surface inaccessible. This study highlights the important role of OM interactions with clay minerals in the preservation of OM in soils and suggests that OM–OM associations may also play a role in the protection of specific OM components in soil.

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Linking molecular and optical properties of dissolved organic matter across a soil-water interface on Akimiski Island (Nunavut, Canada)

The Science of The Total Environment ◽

10.1016/j.scitotenv.2019.135415 ◽

2020 ◽

Vol 704 ◽

pp. 135415 ◽

Cited By ~ 2

Author(s):

V. Mangal ◽

S. DeGasparro ◽

D.V. Beresford ◽

C. Guéguen

Keyword(s):

Organic Matter ◽

Optical Properties ◽

Dissolved Organic Matter ◽

Soil Water ◽

Water Interface ◽

Akimiski Island

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Characterizing Dissolved Organic Matter Across a Riparian Soil–Water Interface: Preliminary Insights from a Molecular Level Perspective

ACS Earth and Space Chemistry ◽

10.1021/acsearthspacechem.1c00029 ◽

2021 ◽

Author(s):

Kai Wang ◽

Yu Pang ◽

Yunyun Li ◽

Chen He ◽

Quan Shi ◽

...

Keyword(s):

Organic Matter ◽

Dissolved Organic Matter ◽

Soil Water ◽

Molecular Level ◽

Water Interface

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Mobility of soil water-soluble organic matter during rice cultivation

Russian Agricultural Sciences ◽

10.3103/s1068367412010090 ◽

2012 ◽

Vol 38 (1) ◽

pp. 40-42 ◽

Cited By ~ 2

Author(s):

O. A. Gutorova ◽

A. Kh. Sheudzhen ◽

A. G. Ladatko

Keyword(s):

Organic Matter ◽

Soil Water ◽

Rice Cultivation ◽

Water Soluble ◽

Soluble Organic Matter

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In situ arsenic speciation at the soil/water interface of saline-alkaline lakes of the Pantanal, Brazil: A DGT-based approach

The Science of The Total Environment ◽

10.1016/j.scitotenv.2021.150113 ◽

2021 ◽

pp. 150113

Author(s):

José Lucas Martins Viana ◽

Adriana Felix de Souza ◽

Amauris Hechavarría Hernández ◽

Lucas Pellegrini Elias ◽

Carlos Eduardo Eismann ◽

...

Keyword(s):

Soil Water ◽

Arsenic Speciation ◽

Water Interface ◽

Alkaline Lakes

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Soil water repellency persistence after recurrent forest fires on Mount Carmel, Israel

International Journal of Wildland Fire ◽

10.1071/wf12063 ◽

2013 ◽

Vol 22 (4) ◽

pp. 515 ◽

Cited By ~ 19

Author(s):

Naama Tessler ◽

Lea Wittenberg ◽

Noam Greenbaum

Keyword(s):

Organic Matter ◽

Soil Water ◽

Forest Fires ◽

Water Drop ◽

Chemical Properties ◽

Water Repellency ◽

Mediterranean Ecosystem ◽

Long Term Effects ◽

Soil Water Repellency ◽

Chemical Properties Of Soils

Variations in forest fires regime affect: (1) the natural patterns of community structure and vegetation; (2) the physico-chemical properties of soils and consequently (3) runoff, erosion and sediment yield. In recent decades the Mediterranean ecosystem of Mount Carmel, north-western Israel, is subjected to an increasing number of forest fires, thus, the objectives of the study were to evaluate the long-term effects of single and recurrent fires on soil water repellency (WR) and organic matter (OM) content. Water repellency was studied by applying water drop penetration time (WDPT) tests at sites burnt by single-fire, two fires, three fires and unburnt control sites. Water repellency in the burnt sites was significantly lower than in the unburnt control sites, and the soil maintained its wettability for more than 2 decades, whereas after recurrent fires, the rehabilitation was more complicated and protracted. The OM content was significantly lower after recurrent than after a single fire, causing a clear proportional decrease in WR. The rehabilitation of WR to natural values is highly dependent on restoration of organic matter and revegetation. Recurrent fires may cause a delay in recovery and reduced productivity of the soil for a long period.

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