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Boom clay pore water, home of a diverse microbial community

Conference:

Abstract

Document available in extended abstract form only. Boom Clay pore water (BCPW) has been studied in the framework of geological disposal of nuclear waste for over two decades, thereby mainly addressing its geochemical properties. A reference composition for synthetic clay water has been derived earlier by modelling and spatial calibration efforts, mainly based on interstitial water sampled from different layers within the Boom clay. However, since microbial activity is found in a range of extreme circumstances, the possibility of microbes interacting with future radioactive waste in a host formation like Boom Clay, cannot be ignored. In this respect, BCPW was sampled from different Boom Clay layers using the Morpheus piezometer and subsequently analysed by a complementary set of microbiological and molecular techniques, in search for overall shared and abundant microorganisms. Similar to the previous characterization of the 'average' BCPW chemical composition, the primary aim of this microbiological study is to determine a representative BCPW microbial community which can be used in laboratory studies. Secondly, the in situ activity and the metabolic properties of members of this community were addressed, aiming to assess their survival and proliferation chances in repository conditions. In a first approach, total microbial DNA of the community  More>>
Authors:
Wouters, Katinka; Moors, Hugo; Leys, Natalie [1] 
  1. SCK.CEN, Environment, Health and Safety Institute, B-2400 Mol (Belgium)
Publication Date:
Oct 15, 2012
Product Type:
Conference
Report Number:
INIS-FR-13-0158
Resource Relation:
Conference: 5. international meeting on clays in natural and engineered barriers for radioactive waste confinement, Montpellier (France), 22-25 Oct 2012; Other Information: Available from the INIS Liaison Officer for France, see the 'INIS contacts' section of the INIS website for current contact and E-mail addresses: http://www.iaea.org/INIS/contacts/; Related Information: In: Clays in natural and engineered barriers for radioactive waste confinement - 5. International meeting. Book of abstracts| 923 p.
Subject:
60 APPLIED LIFE SCIENCES; ATP; BACTERIA; BOOM CLAY; CELL CULTURES; DNA SEQUENCING; INTERSTITIAL WATER; METABOLISM; POLYMERASE CHAIN REACTION; SCANNING ELECTRON MICROSCOPY; SPECIES DIVERSITY; TAXONOMY
OSTI ID:
22090097
Research Organizations:
Agence nationale pour la gestion des dechets radioactifs - Andra, 1/7, rue Jean Monnet, Parc de la Croix-Blanche, 92298 Chatenay-Malabry cedex (France)
Country of Origin:
France
Language:
English
Other Identifying Numbers:
TRN: FR1300986048851
Availability:
Available from INIS in electronic form
Submitting Site:
INIS
Size:
page(s) 112-113
Announcement Date:
Apr 25, 2013

Conference:

Citation Formats

Wouters, Katinka, Moors, Hugo, and Leys, Natalie. Boom clay pore water, home of a diverse microbial community. France: N. p., 2012. Web.
Wouters, Katinka, Moors, Hugo, & Leys, Natalie. Boom clay pore water, home of a diverse microbial community. France.
Wouters, Katinka, Moors, Hugo, and Leys, Natalie. 2012. "Boom clay pore water, home of a diverse microbial community." France.
@misc{etde_22090097,
title = {Boom clay pore water, home of a diverse microbial community}
author = {Wouters, Katinka, Moors, Hugo, and Leys, Natalie}
abstractNote = {Document available in extended abstract form only. Boom Clay pore water (BCPW) has been studied in the framework of geological disposal of nuclear waste for over two decades, thereby mainly addressing its geochemical properties. A reference composition for synthetic clay water has been derived earlier by modelling and spatial calibration efforts, mainly based on interstitial water sampled from different layers within the Boom clay. However, since microbial activity is found in a range of extreme circumstances, the possibility of microbes interacting with future radioactive waste in a host formation like Boom Clay, cannot be ignored. In this respect, BCPW was sampled from different Boom Clay layers using the Morpheus piezometer and subsequently analysed by a complementary set of microbiological and molecular techniques, in search for overall shared and abundant microorganisms. Similar to the previous characterization of the 'average' BCPW chemical composition, the primary aim of this microbiological study is to determine a representative BCPW microbial community which can be used in laboratory studies. Secondly, the in situ activity and the metabolic properties of members of this community were addressed, aiming to assess their survival and proliferation chances in repository conditions. In a first approach, total microbial DNA of the community was extracted from the BCPW samples. This molecular approach allows a broad insight in the total microbial ecology of the BCPW samples. By polymerase chain reaction (PCR) on the highly conserved 16S rRNA genes in this DNA pool and subsequent sequencing and bio-informatics analysis, operational taxonomic units (OTUs) could be assigned to the microbial community. The bacterial community was found to be quite diverse, with OTUs belonging to 8 different phyla (Proteobacteria, Actinobacteria, Firmicutes, Bacteroidetes, Chlorobi, Spirochetes, Chloroflexi and Deinococcus-Thermus). These results provide an overall view of the structure and phylogeny of the bacterial population, without however any visual conformation or indication of in situ activity. In a second approach therefore, microbial presence, activity and metabolic capacity in BCPW samples was assessed by respectively scanning electron microscopy (SEM), analysis of intracellular adenosine triphosphate (ATP) and cultivation in relevant, anaerobic media by most probable number technique (MPN). Microbial presence was confirmed to be abundant, up to an average of 108 cultivable cells per mL and 10{sup 7} metabolically active cells per mL. To evaluate specific properties of these cultivated subpopulations, individual microbial strains were isolated and identified in a third approach. Fifteen different bacterial genera were identified, belonging to the Proteobacteria (5), Actinobacteria (5), Firmicutes (2) and Bacteroidetes (3). The isolates are very similar to commonly found environmental strains with relevant capacities for survival in the stringent conditions of Boom clay, like sulphide dependence, sporulation, (facultative) anaerobic metabolism or oligo-trophy. Comparison with the OTU-based analysis reveals that the isolates covered the population surprisingly well in terms of bacterial phyla. Most importantly, their significance in the community could be estimated in terms of relative abundance and omnipresence. Combining these results, a representative BCPW microbial community composition was characterized. In fulfilment of the first aim, a combination of three BCPW piezometer filters (Morpheus F6-F9-F23) was selected to serve as representative microbial community sample for future lab scale experiments. As for the second aim, the omnipresence of such a diverse and in situ active microbial community is surprising. Microbial contamination during piezometer installation and survival of introduced species during several years in stringent conditions are therefore considered quite credible. On the other hand, the indicated diversity of anaerobic micro-organisms with specific properties like sulphate reduction and sporulation invites speculations that indigenous micro-organisms will account for at least part of the observed viable community. However, regardless of its origin, the characterisation of this ubiquitous and diverse microbial community in Boom Clay repository conditions is indicatory for the importance of microbiological research in the context of safe waste disposal and opens perspectives for more in depth assessments of clay-microbe waste interactions. (authors)}
place = {France}
year = {2012}
month = {Oct}
}