Title: Stability of mineral-organic matter associations under varying biogeochemical conditions

Abstract

It is well-recognized and documented in the literature that a consideraIt is well-recognized and documented in the literature that a considerable fraction of the soil organic matter (SOM) is associated with Fe-oxide minerals. Recent studies have also showed that the persistence of various classes of SOM may depend on soil Fe mineralogy. Other laboratory studies with model mineral-associated organic matter (MAOM) moieties, which were primarily focused on ferrihydrite, either coated or coprecipitated with natural organic matter (NOM), have suggested that the mineral phase transformation and adsorption-desorption of SOM is rather complex but appears to be largely controlled by the C/Fe ratio of the MAOM moiety and geochemical conditions. It is also clear from multiple recent studies that the nature or type of SOM (microbial vs. plant-derived) adsorbed on mineral surfaces and the rate and extent of SOM biodegradation depend on the type of mineral, and/or metal ions, that are associated with the SOM. Modeling studies that are primarily centered on achieving a better understanding of the effect of mineral type on SOM interactions with minerals and degradation are also reported. These studies have improved the understanding of the nature and stability of MAOM in soils of varying types and undermore » different conditions, positioning researchers to better predict the properties and stabilities of organo-mineral associations in soils.ble fraction of the soil organic matter (SOM) is associated with Fe-oxide minerals. Recent studies have also showed that the persistence of various classes of SOM may depend on soil Fe mineralogy. Other laboratory studies with model mineral-associated organic matter (MAOM) moieties, which were primarily focused on the short-range ordered (SRO) Fe-mineral, such as ferrihydrite, either coated or co-precipitated with natural organic matter (NOM) have suggested that the mineral phase transformation and adsorption/desorption of SOM is rather complex, but appears to be largely controlled by the C/Fe ratio of the MAOM moiety and geochemical conditions. It’s also clear from multiple recent studies that the nature or type of SOM (microbial vs. plant-derived) adsorbed on mineral surfaces, and the rate and extent of SOM bio-degradation depend on the type of mineral (e.g., ferrihydrite, Fe-containing phyllosilicate minerals, calcite), and/or metal ions (e.g., Al, Fe, and Ca), that are associated with the SOM. Modeling studies that are primarily centered on achieving a better understanding of the effect of mineral type on SOM interactions with minerals and degradation are also reported. These studies have improved the understanding of the nature and stability of MAOM in soils of varying types and under different conditions, positioning researchers to better predict the properties and stabilities of organo-mineral associations in soils. This special section includes a collection of studies that span across modeling efforts, modeling coupled with experimental studies, laboratory experimental studies on ferrihydrite-SOM systems that are subjected to anoxic conditions, a study that focused on the effect of temperature on C/Fe ratio of the ferrihydrite-SOM moieties, a laboratory study on the role of adsorbed extracellular polymeric substance (EPS) on acidity of selected soils, a study that used a tropical humid soil enriched in nanogoethite subjected to anaerobic conditions, and a study with a large set of soils from the National Ecological Observatory Network (NEON) subjected to selective chemical extractions to correlate extractable metal and SOM contents.« less

Authors:

Kukkadapu, Ravi K.  ^[1];

• Search DOE PAGES for author "Kukkadapu, Ravi K."
• Search DOE PAGES for ORCID "0000-0001-9763-156X"

Zhao, Qian  ^[1];

• Search DOE PAGES for author "Zhao, Qian"
• Search DOE PAGES for ORCID "0000-0003-4489-3691"

Qafoku, Nikolla P.  ^[2]

• Search DOE PAGES for author "Qafoku, Nikolla P."
• Search DOE PAGES for ORCID "0000-0002-3258-5379"

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+ Show Author Affiliations

1. Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
2. Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Univ. of Washington, Seattle, WA (United States)

Publication Date:

Sun Feb 13 00:00:00 EST 2022

Research Org.:

Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

Sponsoring Org.:

USDOE

OSTI Identifier:

1845279

Alternate Identifier(s):

OSTI ID: 1861782

Report Number(s):

PNNL-SA-170061
Journal ID: ISSN 0361-5995

Grant/Contract Number:  

AC05-76RL01830

Resource Type:

Accepted Manuscript

Journal Name:

Soil Science Society of America Journal

Additional Journal Information:

Journal Volume: 86; Journal Issue: 2; Journal ID: ISSN 0361-5995

Publisher:

Alliance of Crop, Soil, and Environmental Science Societies

Country of Publication:

United States

Language:

English

Subject:

54 ENVIRONMENTAL SCIENCES; density functional theory; dissolved organic matter; extracellular polymeric substance; mineral-associated organic matter; organic matter; soil organic carbon; soil organic matter