Open AccessBacterial community analysis of shallow groundwater undergoing sequential anaerobic and aerobic chloroethene biotransformation
Author(s) -
Miller Todd R.,
Franklin Mark P.,
Halden Rolf U.
Publication year - 2007
Publication title -
fems microbiology ecology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.377
H-Index - 155
eISSN - 1574-6941
pISSN - 0168-6496
DOI - 10.1111/j.1574-6941.2007.00290.x
Subject(s) - deltaproteobacteria , alphaproteobacteria , gammaproteobacteria , biology , environmental chemistry , microbial population biology , proteobacteria , nitrate , groundwater , firmicutes , betaproteobacteria , bacteroidetes , 16s ribosomal rna , microbiology and biotechnology , ecology , actinobacteria , bacteria , chemistry , genetics , geotechnical engineering , engineering
At Department of Energy Site 300, beneficial hydrocarbon cocontaminants and favorable subsurface conditions facilitate sequential reductive dechlorination of trichloroethene (TCE) and rapid oxidation of the resultant cis‐ dichloroethene ( cis ‐DCE) upon periodic oxygen influx. We assessed the geochemistry and microbial community of groundwater from across the site. Removal of cis ‐DCE was shown to coincide with oxygen influx in hydrocarbon‐containing groundwater near the source area. Principal component analysis of contaminants and inorganic compounds showed that monitoring wells could be differentiated based upon concentrations of TCE, cis ‐DCE, and nitrate. Structurally similar communities were detected in groundwater from wells containing cis ‐DCE, high TCE, and low nitrate levels. Bacteria identified by sequencing 16S rRNA genes belonged to seven phylogenetic groups, including Alpha ‐, Beta ‐, Gamma ‐ and Deltaproteobacteria , Nitrospira , Firmicutes and Cytophaga – Flexibacter – Bacteroidetes (CFB). Whereas members of the Burkholderiales and CFB group were abundant in all wells (10 4 –10 9 16S rRNA gene copies L −1 ), quantitative PCR showed that Alphaproteobacteria were elevated (>10 6 L −1 ) only in wells containing hydrocarbon cocontaminants. The study shows that bacterial community structure is related to groundwater geochemistry and that Alphaproteobacteria are enriched in locales where cis ‐DCE removal occurs.