Response of microbial community function to fluctuating geochemical conditions within a legacy radioactive waste trench environment
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Date
2017-08-17
Journal Title
Journal ISSN
Volume Title
Publisher
American Society for Microbiology
Abstract
During the 1960s, small quantities of radioactive materials were codisposed with chemical waste at the Little Forest Legacy Site (Sydney, Australia) in 3-meter-deep, unlined trenches. Chemical and microbial analyses, including functional and taxonomic information derived from shotgun metagenomics, were collected across a 6-week period immediately after a prolonged rainfall event to assess the impact of changing water levels upon the microbial ecology and contaminant mobility. Collectively, results demonstrated that oxygen-laden rainwater rapidly altered the redox balance in the trench water, strongly impacting microbial functioning as well as the radiochemistry. Two contaminants of concern, plutonium and americium, were shown to transition from solid-iron-associated species immediately after the initial rainwater pulse to progressively more soluble moieties as reducing conditions were enhanced. Functional metagenomics revealed the potentially important role that the taxonomically diverse microbial community played in this transition. In particular, aerobes dominated in the first day, followed by an increase of facultative anaerobes/denitrifiers at day 4. Toward the mid-end of the sampling period, the functional and taxonomic profiles depicted an anaerobic community distinguished by a higher representation of dissimilatory sulfate reduction and methanogenesis pathways. Our results have important implications to similar near-surface environmental systems in which redox cycling occurs. © 2017 Vázquez-Campos et al.
Description
This is an open-access article distributed under the terms of the Creative Commons Attribution 4.0 International license.
Keywords
Radioactive wastes, Underground disposal, Radioisotopes, Plutonium, Americium, Rain water, Microorganisms, New South Wales, Australia
Citation
Vázquez-Campos, X., Kinsela, A. S., Bligh, M. W., Harrison, J. J., Payne, T. E., & Waite, T. D. (2017). Response of microbial community function to fluctuating geochemical conditions within a legacy radioactive waste trench environment. Applied and Environmental Microbiology, 83(17), e00729-17. doi:10.1128/AEM.00729-17