title: Mineralogy influences structure and diversity of bacterial communities associated with geological substrata in a pristine aquifer.
abstract: Our understanding of mineralogical influences on subsurface microbial community structure and diversity has been difficult to assess due to difficulties in isolating this variable from others in the subsurface environment. In this study, biofilm coupons were used to isolate specific geological substrata from the surrounding geological matrix during colonization by microorganisms suspended in the surrounding groundwater for an 8-week period. Upon retrieval, the structure and diversity of the microbial community associated with each type of substratum was evaluated using 16S rDNA-based terminal-restriction fragment length polymorphism (T-RFLP). Phylogenetic affiliations of the populations associated with each type of substratum were established based on sequence analysis of near full-length 16S rDNA obtained through construction of a clone library. Hematite, quartz, and saprolite each harbored a community dominated by members of the division Proteobacteria (>67% of community). However, the different substrata selected for different subdivisions of bacteria within the Proteobacteria. After accounting for the influence exerted by substratum type on recovery of DNA from the attached populations, both phylogenetic data and Jaccard and Bray-Curtis similarity indices derived from terminal-restriction fragment (T-RF) profiles suggested a strong mineralogical influence on the structure and composition of the solid phase-associated community. The results suggest that mineralogical heterogeneity influences microbial community structure and diversity in pristine aquifers.
authors.affiliation: Department of Microbiology, Montana State University, Bozeman, MT, USA.
authors.forename: Eric S
authors.initials: ES
authors.lastname: Boyd
authors.forename: David E
authors.initials: DE
authors.lastname: Cummings
authors.forename: Gill G
authors.initials: GG
authors.lastname: Geesey
mesh_terms: D001419:Bacteria / Q000145:classification* / Q000235:genetics / Q000254:growth & development; D044822:Biodiversity; D018441:Biofilms; D004269:DNA, Bacterial / Q000737:chemistry; D005290:Ferric Compounds / Q000737:chemistry; D010802:Phylogeny; D012150:Polymorphism, Restriction Fragment Length; D011791:Quartz / Q000737:chemistry; D012336:RNA, Ribosomal, 16S / Q000737:chemistry; D017422:Sequence Analysis, DNA; D013499:Surface Properties; D014871:Water Microbiology
chemical_list: D004269:DNA, Bacterial; D005290:Ferric Compounds; D012336:RNA, Ribosomal, 16S; D011791:Quartz; C000499:ferric oxide