Subsurface clade of Geobacteraceae that predominates in a diversity of Fe(III)-reducing subsurface environments.
There are distinct differences in the physiology of Geobacter species available in pure culture. Therefore, to understand the ecology of Geobacter species in subsurface environments, it is important to know which species predominate. Clone libraries were assembled with 16S rRNA genes and transcripts amplified from three subsurface environments in which Geobacter species are known to be important members of the microbial community: (1) a uranium-contaminated aquifer located in Rifle, CO, USA undergoing in situ bioremediation; (2) an acetate-impacted aquifer that serves as an analog for the long-term acetate amendments proposed for in situ uranium bioremediation and (3) a petroleum-contaminated aquifer in which Geobacter species play a role in the oxidation of aromatic hydrocarbons coupled with the reduction of Fe(III). The majority of Geobacteraceae 16S rRNA sequences found in these environments clustered in a phylogenetically coherent subsurface clade, which also contains a number of Geobacter species isolated from subsurface environments. Concatamers constructed with 43 Geobacter genes amplified from these sites also clustered within this subsurface clade. 16S rRNA transcript and gene sequences in the sediments and groundwater at the Rifle site were highly similar, suggesting that sampling groundwater via monitoring wells can recover the most active Geobacter species. These results suggest that further study of Geobacter species in the subsurface clade is necessary to accurately model the behavior of Geobacter species during subsurface bioremediation of metal and organic contaminants.
Department of Microbiology, Morrill IV North Science Center, University of Massachusetts, Amherst, MA, USA. dholmes@microbio.umass.edu
Dawn E
DE
Holmes
Regina A
RA
O'Neil
Helen A
HA
Vrionis
Lucie A
LA
N'guessan
Irene
I
Ortiz-Bernad
Maria J
MJ
Larrahondo
Lorrie A
LA
Adams
Joy A
JA
Ward
Julie S
JS
Nicoll
Kelly P
KP
Nevin
Milind A
MA
Chavan
Jessica P
JP
Johnson
Philip E
PE
Long
Derek R
DR
Lovley
D001673:Biodegradation, Environmental; D017753:Ecosystem; D005290:Ferric Compounds / Q000378:metabolism*; D045302:Geobacter / Q000145:classification / Q000235:genetics* / Q000378:metabolism; D006841:Hydrocarbons, Aromatic / Q000378:metabolism; D008969:Molecular Sequence Data; D010084:Oxidation-Reduction; D010578:Petroleum / Q000378:metabolism; D010802:Phylogeny; D016133:Polymerase Chain Reaction; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D017422:Sequence Analysis, DNA; D014501:Uranium / Q000378:metabolism
D005290:Ferric Compounds; D006841:Hydrocarbons, Aromatic; D010578:Petroleum; D012336:RNA, Ribosomal, 16S; D014501:Uranium