title: Bacterial diversity of terrestrial crystalline volcanic rocks, Iceland.
abstract: Bacteria inhabiting crystalline rocks from two terrestrial Icelandic volcanic lava flows of similar age and from the same geographical region, but differing in porosity and mineralogy, were characterised. Microarray (PhyloChip) and clone library analysis of 16S rRNA genes revealed the presence of a diverse assemblage of bacteria in each lava flow. Both methods suggested a more diverse community at the Dómadalshraun site (rhyolitic/andesitic lava flow) than that present at the Hnausahraun site (basaltic lava flow). Proteobacteria dominated the clone library at the Dómadalshraun site, while Acidobacteria was the most abundant phylum in the Hnausahraun site. Although analysis of similarities of denaturing gradient gel electrophoresis profiles suggested a strong correlation of community structure with mineralogy, rock porosity may also play an important role in shaping the bacterial community in crystalline volcanic rocks. Clone sequences were most similar to uncultured microorganisms, mainly from soil environments. Of these, Antarctic soils and temperate rhizosphere soils were prominent, as were clones retrieved from Hawaiian and Andean volcanic soils. The novel diversity of these Icelandic microbial communities was supported by the finding that up to 46% of clones displayed <85% sequence identities to sequences currently deposited in the RDP database.
authors.affiliation: Geomicrobiology Research Group, Planetary and Space Sciences Research Institute, Open University, Milton Keynes, MK7 6AA, UK. lckelly23@hotmail.com
authors.forename: Laura C
authors.initials: LC
authors.lastname: Kelly
authors.forename: Charles S
authors.initials: CS
authors.lastname: Cockell
authors.forename: Aude
authors.initials: A
authors.lastname: Herrera-Belaroussi
authors.forename: Yvette
authors.initials: Y
authors.lastname: Piceno
authors.forename: Gary
authors.initials: G
authors.lastname: Andersen
authors.forename: Todd
authors.initials: T
authors.lastname: DeSantis
authors.forename: Eoin
authors.initials: E
authors.lastname: Brodie
authors.forename: Thorsteinn
authors.initials: T
authors.lastname: Thorsteinsson
authors.forename: Viggó
authors.initials: V
authors.lastname: Marteinsson
authors.forename: Franck
authors.initials: F
authors.lastname: Poly
authors.forename: Xavier
authors.initials: X
authors.lastname: LeRoux
mesh_terms: D001419:Bacteria / Q000145:classification / Q000235:genetics / Q000302:isolation & purification*; D044822:Biodiversity; D019015:Geologic Sediments / Q000737:chemistry / Q000382:microbiology*; D007055:Iceland; D008969:Molecular Sequence Data; D010802:Phylogeny; D018707:Volcanic Eruptions / Q000032:analysis*