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Title: Imaging and Analytical Approaches for Characterization of Soil Mineral Weathering

Abstract

Soil minerals weathering is the primary natural source of nutrients necessary to sustain productivity in terrestrial ecosystems. Soil microbial communities increase soil mineral weathering and mineral-derived nutrient availability through physical and chemical processes. Rhizosphere, the zone immediately surrounding plant roots, is a biogeochemical hotspot with microbial activity, soil organic matter production, mineral weathering, and secondary phase formation all happening in a small temporally ephemeral zone of steep geochemical gradients. The detailed exploration of the micro-scale rhizosphere is essential to our better understanding of large-scale processes in soils, such as nutrient cycling, transport and fate of soil components, microbial-mineral interactions, soil erosion, soil organic matter turnover and its molecular-level characterization, and predictive modeling.

Authors:
; ; ; ;
Publication Date:
Research Org.:
Pacific Northwest National Laboratory (PNNL), Richland, WA (US), Environmental Molecular Sciences Laboratory (EMSL)
Sponsoring Org.:
USDOE
OSTI Identifier:
1398170
Report Number(s):
PNNL-SA-126363
Journal ID: ISSN 1431-9276; applab; 49147
DOE Contract Number:
AC05-76RL01830
Resource Type:
Journal Article
Resource Relation:
Journal Name: Microscopy and Microanalysis; Journal Volume: 23; Journal Issue: S1
Country of Publication:
United States
Language:
English
Subject:
Environmental Molecular Sciences Laboratory

Citation Formats

Dohnalkova, Alice, Arey, Bruce, Varga, Tamas, Miller, Micah, and Kovarik, Libor. Imaging and Analytical Approaches for Characterization of Soil Mineral Weathering. United States: N. p., 2017. Web. doi:10.1017/S1431927617011527.
Dohnalkova, Alice, Arey, Bruce, Varga, Tamas, Miller, Micah, & Kovarik, Libor. Imaging and Analytical Approaches for Characterization of Soil Mineral Weathering. United States. doi:10.1017/S1431927617011527.
Dohnalkova, Alice, Arey, Bruce, Varga, Tamas, Miller, Micah, and Kovarik, Libor. Sat . "Imaging and Analytical Approaches for Characterization of Soil Mineral Weathering". United States. doi:10.1017/S1431927617011527.
@article{osti_1398170,
title = {Imaging and Analytical Approaches for Characterization of Soil Mineral Weathering},
author = {Dohnalkova, Alice and Arey, Bruce and Varga, Tamas and Miller, Micah and Kovarik, Libor},
abstractNote = {Soil minerals weathering is the primary natural source of nutrients necessary to sustain productivity in terrestrial ecosystems. Soil microbial communities increase soil mineral weathering and mineral-derived nutrient availability through physical and chemical processes. Rhizosphere, the zone immediately surrounding plant roots, is a biogeochemical hotspot with microbial activity, soil organic matter production, mineral weathering, and secondary phase formation all happening in a small temporally ephemeral zone of steep geochemical gradients. The detailed exploration of the micro-scale rhizosphere is essential to our better understanding of large-scale processes in soils, such as nutrient cycling, transport and fate of soil components, microbial-mineral interactions, soil erosion, soil organic matter turnover and its molecular-level characterization, and predictive modeling.},
doi = {10.1017/S1431927617011527},
journal = {Microscopy and Microanalysis},
number = S1,
volume = 23,
place = {United States},
year = {Sat Jul 01 00:00:00 EDT 2017},
month = {Sat Jul 01 00:00:00 EDT 2017}
}
  • Microscopic and spectroscopic studies were conducted to assess mineral transformation processes in aqueous suspensions of illite (Il), vermiculite (Vm) and montmorillonite (Mt) that were subjected to weathering in a simulated high-level radioactive tank waste leachate (0.05 m AlT, 2 m Na*, 1 m NO3 *, pH *14, Cs* and Sr2* present as co-contaminants). Time series (0 to 369 d) experiments were conducted at 298 K, with initial [Cs]0 and [Sr]0 concentrations from 10*5 to 10* mol kg*. Incongruent clay dissolution resulted in an accumulation of secondary aluminosilicate precipitates identified as nitrate-sodalite, nitrate-cancrinite and zeolite X, by molecular spectroscopy and electronmore » microscopy (XRD, IR, NMR, SEM-EDS and TEM-EDS). Contaminant fate was dependent on competing uptake to parent clays and weathering products. TEM-EDS results indicated that high Il affinity for Cs was due to adsorption at frayed edge sites. The Il system also comprised Sr-rich aluminous precipitates after 369 d reaction time. In Mt systems, Cs and Sr were co-precipitated into increasingly recalcitrant spheroidal precipitates over the course of the experiment, whereas contaminant association with montmorillonite platelets was less prevalent. In contrast, Cs and Sr were found in association with weathered Vm particles despite the formation of spheroidal aluminosilicate precipitates that were comparable to those formed from Mt dissolution.« less
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