title: Benthic bacterial diversity from freshwater tufas of the Iberian Range (Spain).
abstract: Aiming to characterize the bacterial diversity of modern tufa systems of the Iberian Range (Spain), we surveyed the 16S rRNA gene sequence diversity from 24 sites within three rivers (Añamaza, Mesa and Piedra). These tufas record substantial calcareous growth under different physicochemical conditions and are part of an important, regional landscape-building system. The bacterial community structure and composition, richness and diversity were quantified from denaturing gradient gel electrophoresis fingerprints. Retrieved DNA sequences could be assigned to 10 bacterial phyla and included a variety of phototrophic and heterotrophic groups. Cyanobacteria, mainly filamentous taxa, constituted 43% of all the retrieved sequences, followed by Firmicutes (11%), Gammaproteobacteria (10%), Alphaproteobacteria (7%), Acidobacteria (6%), Bacteroidetes (5%), Betaproteobacteria (4%), Planctomycetes (4%), Actinobacteria (3%) and Deltaproteobacteria (2%). Diatom and Xanthophyceae chloroplast sequences were also detected. Physicochemical variables measured at each site were modelled with multivariate statistics. Principal component analyses yielded the highest variance for salinity-related variables (conductivity; Na(+) , Cl(-) and SO4(2-) concentrations), which correlated negatively and significantly with diversity indices. However, the highest variance explained by individual principal components was relatively low (< 34%). Overall, we show that these young fluvial tufas are inhabited by a large variety of bacteria in diverse and widespread communities.
authors.affiliation: Institute of Geology, UNAM, Ciudad Universitaria, Mexico City, Mexico. hberaldi@unam.mx
authors.forename: Hugo
authors.initials: H
authors.lastname: Beraldi-Campesi
authors.forename: Concepción
authors.initials: C
authors.lastname: Arenas-Abad
authors.forename: Ferran
authors.initials: F
authors.lastname: Garcia-Pichel
authors.forename: Omar
authors.initials: O
authors.lastname: Arellano-Aguilar
authors.forename: Luis
authors.initials: L
authors.lastname: Auqué
authors.forename: Marta
authors.initials: M
authors.lastname: Vázquez-Urbez
authors.forename: Carlos
authors.initials: C
authors.lastname: Sancho
authors.forename: Cinta
authors.initials: C
authors.lastname: Osácar
authors.forename: Silvia
authors.initials: S
authors.lastname: Ruiz-Velasco
mesh_terms: D001419:Bacteria / Q000145:classification* / Q000235:genetics / Q000254:growth & development; D058645:Denaturing Gradient Gel Electrophoresis; D017753:Ecosystem; D005618:Fresh Water / Q000382:microbiology*; D014644:Genetic Variation; D010802:Phylogeny; D012336:RNA, Ribosomal, 16S / Q000032:analysis / Q000235:genetics; D017422:Sequence Analysis, DNA; D013030:Spain; D014871:Water Microbiology
chemical_list: D012336:RNA, Ribosomal, 16S