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

doi:10.2172/1045985

GSTDTAP > 地球科学

DOI	10.2172/1045985
报告编号	LA-UR-12-22824
来源ID	OSTI ID: 1045985
	Status Report on the Microbial Characterization of Halite and Groundwater Samples from the WIPP
	Swanson, Juliet S. [Los Alamos National Laboratory]; Reed, Donald T. [Los Alamos National Laboratory]; Ams, David A. [Los Alamos National Laboratory]; Norden, Diana [Ohio State University]; Simmons, Karen A. [Los Alamos National Laboratory]
	2012-07-10
出版年	2012
语种	英语
国家	美国
领域	地球科学
英文摘要	This report summarizes the progress made in the ongoing task of characterizing the microbial community structures within the WIPP repository and in surrounding groundwaters. Through cultivation and DNA-based identification, the potential activity of these organisms is being inferred, thus leading to a better understanding of their impact on WIPP performance. Members of the three biological domains - Bacteria, Archaea, and Eukarya (in this case, Fungi) - that are associated with WIPP halite have been identified. Thus far, their activity has been limited to aerobic respiration; anaerobic incubations are underway. WIPP halite constitutes the near-field microbial environment. We expect that microbial activity in this setting will proceed from aerobic respiration, through nitrate reduction to focus on sulfate reduction. This is also the current WIPP performance assessment (PA) position. Sulfate reduction can occur at extremely high ionic strengths, and sulfate is available in WIPP brines and in the anhydrite interbeds. The role of methanogenesis in the WIPP remains unclear, due to both energetic constraints imposed by a high-salt environment and substrate selectivity, and it is no longer considered in PA. Archaea identified in WIPP halite thus far fall exclusively within the family Halobacteriaceae. These include Halobacterium noricense, cultivated from both low- and high-salt media, and a Halorubrum-like species. The former has also been detected in other salt mines worldwide; the latter likely constitutes a new species. Little is known of its function, but it was prevalent in experiments investigating the biodegradation of organic complexing agents in WIPP brines. Bacterial signatures associated with WIPP halite include members of the phylum Proteobacteria - Halomonas, Pelomonas, Limnobacter, and Chromohalobacter - but only the latter has been isolated. Also detected and cultivated were Salinicoccus and Nesterenkonia spp. Fungi were also isolated from halite. Although these were most likely introduced into the WIPP as contaminants from above-ground, their survival and potential role in the WIPP (e.g., cellulose degradation) is under investigation. WIPP groundwaters comprise the far-field microbial environment. Bacteria cultivated and identified from the overlying Culebra and nearby borehole groundwater are capable of aerobic respiration, denitrification, fermentation, metal reduction, and sulfate reduction and are distributed across many different phyla. Two of the Bacteria found in groundwater were also found in WIPP halite (Chromohalobacter sp. and Virgibacillus sp.). Archaea identified in groundwater include Halococcus saccharolyticus, Haloferax sp., and Natrinema sp. The differences in the microbial communities detected thus far in halite and groundwater suggest that there will be significant differences in the associated metabolic potential of the near- and far-field environments. Whereas the near-field is dominated by Archaea with more limited metabolic capabilities, the far-field is dominated by Bacteria with extremely broad capabilities. Because the majority of the repository's lifetime will be anoxic, ongoing and future work focuses on the presence and role of anaerobic organisms in WIPP. Further tasks on biosorption, cellulose degradation, and bioreduction are being performed using organisms obtained from this characterization work.
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来源平台	US Department of Energy (DOE)
引用统计
文献类型	科技报告
条目标识符	http://119.78.100.173/C666/handle/2XK7JSWQ/5907
专题	地球科学
推荐引用方式 GB/T 7714	Swanson, Juliet S. [Los Alamos National Laboratory],Reed, Donald T. [Los Alamos National Laboratory],Ams, David A. [Los Alamos National Laboratory],et al. Status Report on the Microbial Characterization of Halite and Groundwater Samples from the WIPP,2012.