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Archaeal communities from mercury and uranium-contaminated freshwater stream sediments were characterized and compared to archaeal communities present in an uncontaminated stream located in the vicinity of Oak Ridge, TN, USA. The distribution of the Archaea was determined by pyrosequencing analysis of the V4 region of 16S rRNA amplified from 12 streambed(More)
Genomic techniques commonly used for assessing distributions of microorganisms in the environment often produce small sample sizes. We investigated artificial neural networks for analyzing the distributions of nitrite reductase genes (nirS and nirK) and two sets of dissimilatory sulfite reductase genes (dsrAB1 and dsrAB2) in small sample sets. Data(More)
  • Henrietta I Jager, W W Hargrove, C C Brandt, A W King, R J Olson, J M O Scurlock +1 other
  • 2000
Reducing uncertainty in predictions of regional-scale models depends on meaningful contrasts with field measurements. This paper introduces a two-stage process that works from the premise that an appropriate goal for regional models is to produce reasonable behavior over dominant environmental gradients. We demonstrate two techniques for contrasting models(More)
In a complex environment, it can be difficult to assess the degree to which an environmental variable influences microbial community structure. We propose a method that uses the community data to "predict" the value of the presumed dominant variable. The assumption is that in order to "predict" the variable, the community composition must be sensitive to or(More)
Mercury (Hg) methylation produces the neurotoxic, highly bioaccumulative methylmercury (MeHg). The highly conserved nature of the recently identified Hg methylation genes hgcAB provides a foundation for broadly evaluating spatial and niche-specific patterns of microbial Hg methylation potential in nature. We queried hgcAB diversity and distribution in >3500(More)
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