Denitrifying bacteria from the genus Rhodanobacter dominate bacterial communities in the highly contaminated subsurface of a nuclear legacy waste site

Journal Article · Sat Jan 01 00:00:00 EST 2011 · Applied and Environmental Microbiology

OSTI ID:1033998

Green, Stefan ^[1]; Prakash, Om ^[1]; Jasrotia, Puja ^[1]; Overholt, Will ^[1]; Cardenas, Erick ^[2]; Hubbard, Daniela ^[1]; Tiedje, James M. ^[2]; Watson, David B ^[3]; Schadt, Christopher Warren ^[3]; Brooks, Scott C ^[3]; Kostka, Joel ^[1]

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1. Florida State University
2. Michigan State University, East Lansing
3. ORNL

The effect of long-term mixed-waste contamination, particularly uranium and nitrate, on the microbial community in the terrestrial subsurface was investigated at the field scale at the Oak Ridge Integrated Field Research Challenge (ORIFRC) site in Oak Ridge, TN. The abundance, community composition, and distribution of groundwater microorganisms were examined across the site during two seasonal sampling events. At representative locations, subsurface sediment was also examined from two boreholes, one sampled from the most heavily contaminated area of the site and another from an area with low contamination. A suite of DNA- and RNA-based molecular tools were employed for community characterization, including quantitative PCR of ribosomal RNA and nitrite reductase genes, community composition fingerprinting analysis, and high-throughput pyrotag sequencing of rRNA genes. The results demonstrate that pH is a major driver of the subsurface microbial community structure, and denitrifying bacteria from the genus Rhodanobacter (class Gammaproteobacteria) dominate at low pH. The relative abundance of bacteria from this genus was positively correlated with lower pH conditions, and these bacteria were abundant and active in the most highly contaminated areas. Other factors, such as concentration of nitrogen species, oxygen and sampling season did not appear to strongly influence the distribution of Rhodanobacter. Results indicate that these organisms are acid-tolerant denitrifiers, well suited to the acidic, nitrate-rich subsurface conditions, and pH is confirmed as a dominant driver of bacterial community structure in this contaminated subsurface environment.

• Research Organization: Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
• Sponsoring Organization: USDOE
• DOE Contract Number: DE-AC05-00OR22725
• OSTI ID: 1033998
• Journal Information: Applied and Environmental Microbiology, Vol. 78, Issue 4; ISSN 0099-2240
• Country of Publication: United States
• Language: English

Related Subjects

59 BASIC BIOLOGICAL SCIENCES
54 ENVIRONMENTAL SCIENCES
ABUNDANCE
BACTERIA
CONTAMINATION
DENITRIFICATION
DISTRIBUTION
DNA
GENES
GROUND WATER
MICROORGANISMS
NITRITES
NITROGEN
OXIDOREDUCTASES
OXYGEN
PH VALUE
POLYMERASE CHAIN REACTION
RNA
RIBOSOMAL RNA
SAMPLING
SEDIMENTS
TERRESTRIAL ECOSYSTEMS
URANIUM
WASTES
Oak Ridge IFRC
ORIFRC