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Dive into the research topics where Juliet S. Swanson is active.

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Featured researches published by Juliet S. Swanson.


Journal of Hazardous Materials | 2017

Multistage bioassociation of uranium onto an extremely halophilic archaeon revealed by a unique combination of spectroscopic and microscopic techniques

Miriam Bader; Katharina Müller; Harald Foerstendorf; Björn Drobot; Matthias Schmidt; Niculina Musat; Juliet S. Swanson; Donald T. Reed; Thorsten Stumpf; Andrea Cherkouk

The interactions of two extremely halophilic archaea with uranium were investigated at high ionic strength as a function of time, pH and uranium concentration. Halobacterium noricense DSM-15987 and Halobacterium sp. putatively noricense, isolated from the Waste Isolation Pilot Plant repository, were used for these investigations. The kinetics of U(VI) bioassociation with both strains showed an atypical multistage behavior, meaning that after an initial phase of U(VI) sorption, an unexpected interim period of U(VI) release was observed, followed by a slow reassociation of uranium with the cells. By applying in situ attenuated total reflection Fourier-transform infrared spectroscopy, the involvement of phosphoryl and carboxylate groups in U(VI) complexation during the first biosorption phase was shown. Differences in cell morphology and uranium localization become visible at different stages of the bioassociation process, as shown with scanning electron microscopy in combination with energy dispersive X-ray spectroscopy. Our results demonstrate for the first time that association of uranium with the extremely halophilic archaeon is a multistage process, beginning with sorption and followed by another process, probably biomineralization.


PLOS ONE | 2018

Comparative analysis of uranium bioassociation with halophilic bacteria and archaea

Miriam Bader; Katharina Müller; Harald Foerstendorf; Matthias H. Schmidt; Karen Simmons; Juliet S. Swanson; Donald T. Reed; Thorsten Stumpf; Andrea Cherkouk

Rock salt represents a potential host rock formation for the final disposal of radioactive waste. The interactions between indigenous microorganisms and radionuclides, e.g. uranium, need to be investigated to better predict the influence of microorganisms on the safety assessment of the repository. Hence, the association process of uranium with two microorganisms isolated from rock salt was comparatively studied. Brachybacterium sp. G1, which was isolated from the German salt dome Gorleben, and Halobacterium noricense DSM15987T, were selected as examples of a moderately halophilic bacterium and an extremely halophilic archaeon, respectively. The microorganisms exhibited completely different association behaviors with uranium. While a pure biosorption process took place with Brachybacterium sp. G1 cells, a multistage association process occurred with the archaeon. In addition to batch experiments, in situ attenuated total reflection Fourier-transform infrared spectroscopy was applied to characterize the U(VI) interaction process. Biosorption was identified as the dominating process for Brachybacterium sp. G1 with this method. Carboxylic functionalities are the dominant interacting groups for the bacterium, whereas phosphoryl groups are also involved in U(VI) association by the archaeon H. noricense.


Geomicrobiology Journal | 2013

Degradation of Organic Complexing Agents by Halophilic Microorganisms in Brines

Juliet S. Swanson; Diana M. Norden; Hnin Khaing; Donald T. Reed

The potential use of geologic salt beds as terminal repositories for nuclear waste has necessitated research on the interaction of the waste with indigenous microbiota. Microorganisms may affect actinide solubility by degrading organic complexing agents present in the waste. A halophilic bacterium and Archaea indigenous to a salt formation in New Mexico were examined for their ability to degrade acetate, oxalate, citrate, and ethylenediamine tetraacetate under aerobic conditions in low and high-magnesium brines. All complexing agents, except EDTA, were utilized, suggesting that microorganisms indigenous to such repositories can potentially play a beneficial role in mitigating actinide mobility.


Archive | 2016

The Microbiology of Subsurface, Salt-Based Nuclear Waste Repositories: Using Microbial Ecology, Bioenergetics, and Projected Conditions to Help Predict Microbial Effects on Repository Performance

Juliet S. Swanson; Andrea Cherkouk; Thuro Arnold; Artur Meleshyn; Donald T. Reed

This report summarizes the potential role of microorganisms in salt-based nuclear waste repositories using available information on the microbial ecology of hypersaline environments, the bioenergetics of survival under high ionic strength conditions, and “repository microbiology” related studies. In areas where microbial activity is in question, there may be a need to shift the research focus toward feasibility studies rather than studies that generate actual input for performance assessments. In areas where activity is not necessary to affect performance (e.g., biocolloid transport), repository-relevant data should be generated. Both approaches will lend a realistic perspective to a safety case/performance scenario that will most likely underscore the conservative value of that case.


Archive | 2012

Iron Corrosion Observations: Pu(VI)-Fe Reduction Studies

Donald T. Reed; Juliet S. Swanson; Michael K. Richmann; Jean-Francois Lucchini; Marian Borkowski

Iron and Pu Reduction: (1) Very different appearances in iron reaction products were noted depending on pH, brine and initial iron phase; (2) Plutonium was associated with the Fe phases; (3) Green rust was often noted at the higher pH; (4) XANES established the green rust to be an Fe2/3 phase with a bromide center; and (5) This green rust phase was linked to Pu as Pu(IV).


Geochimica et Cosmochimica Acta | 2013

The effect of high ionic strength on neptunium (V) adsorption to a halophilic bacterium

David A Ams; Juliet S. Swanson; Jennifer E. S. Szymanowski; Michael K. Richmann; Donald T. Reed


Archive | 2012

Status Report on the Microbial Characterization of Halite and Groundwater Samples from the WIPP

Juliet S. Swanson; Donald T. Reed; David A Ams; Diana M. Norden; Karen Simmons


Archive | 2017

The Role of Chromohalobacter on Transport of Lanthanides and Cesium in the Dolomite Mineral System

Frances Zengotita; Hilary Palmer Emerson; Timothy M. Dittrich; Juliet S. Swanson; Donald T. Reed


Archive | 2017

Role of Biosorption and Biocolloid Enhancement Factor Parameters in Radionuclide Transport Modeling

Timothy M. Dittrich; Juliet S. Swanson; Michael K. Richmann; Donald T. Reed


Archive | 2013

LANL-CO ACRSP LCO-ACP-15

Jean Francois Lucchini; Marian Borkowski; Hnin Khaing; Michael K. Richmann; Juliet S. Swanson; Karen Simmons; Donald T. Reed

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Donald T. Reed

Los Alamos National Laboratory

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Hnin Khaing

Los Alamos National Laboratory

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Michael K. Richmann

Los Alamos National Laboratory

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David A Ams

Los Alamos National Laboratory

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Jean Francois Lucchini

Los Alamos National Laboratory

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Jean-Francois Lucchini

Los Alamos National Laboratory

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Karen Simmons

Los Alamos National Laboratory

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Andrea Cherkouk

Helmholtz-Zentrum Dresden-Rossendorf

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