title: Community structure of subsurface biofilms in the thermal sulfidic caves ofAcquasanta Terme, Italy.
abstract: We performed a microbial community analysis of biofilms inhabiting thermal (35 to 50 degrees C) waters more than 60 m below the ground surface near Acquasanta Terme, Italy. The groundwater hosting the biofilms has 400 to 830 microM sulfide, <10 microM O(2), pH of 6.3 to 6.7, and specific conductivity of 8,500 to 10,500 microS/cm. Based on the results of 16S rRNA gene cloning and fluorescent in situ hybridization (FISH), the biofilms have low species richness, and lithoautotrophic (or possibly mixotrophic) Gamma- and Epsilonproteobacteria are the principle biofilm architects. Deltaproteobacteria sequences retrieved from the biofilms have <90% 16S rRNA similarity to their closest relatives in public databases and may represent novel sulfate-reducing bacteria. The Acquasanta biofilms share few species in common with Frasassi cave biofilms (13 degrees C, 80 km distant) but have a similar community structure, with representatives in the same major clades. The ecological success of Sulfurovumales-group Epsilonproteobacteria in the Acquasanta biofilms is consistent with previous observations of their dominance in sulfidic cave waters with turbulent water flow and high dissolved sulfide/oxygen ratios.
authors.affiliation: Department of Geosciences, Pennsylvania State University, University Park, PA 16802, USA.
authors.forename: D S
authors.initials: DS
authors.lastname: Jones
authors.forename: D J
authors.initials: DJ
authors.lastname: Tobler
authors.forename: I
authors.initials: I
authors.lastname: Schaperdoth
authors.forename: M
authors.initials: M
authors.lastname: Mainiero
authors.forename: J L
authors.initials: JL
authors.lastname: Macalady
mesh_terms: D000818:Animals; D001419:Bacteria / Q000145:classification* / Q000235:genetics / Q000302:isolation & purification*; D018441:Biofilms / Q000254:growth & development*; D058448:Biota; D016000:Cluster Analysis; D004269:DNA, Bacterial / Q000737:chemistry / Q000235:genetics; D004275:DNA, Ribosomal / Q000737:chemistry / Q000235:genetics; D004553:Electric Conductivity; D045482:Hot Springs / Q000382:microbiology*; D017404:In Situ Hybridization, Fluorescence; D007558:Italy; D008969:Molecular Sequence Data; D010802:Phylogeny; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D017422:Sequence Analysis, DNA; D013440:Sulfides / Q000032:analysis*; D014867:Water / Q000737:chemistry*
chemical_list: D004269:DNA, Bacterial; D004275:DNA, Ribosomal; D012336:RNA, Ribosomal, 16S; D013440:Sulfides; D014867:Water