Phylogenetic characterization of the blue filamentous bacterial community from an Icelandic geothermal spring.

Molecular phylogenetic analysis of a blue filamentous community from an alkaline thermal spring (79-83 degrees C) in Iceland revealed that the blue filaments were affiliated with the Aquificales. The dominant sequence type, pIce1, was most closely related to a sequence (SRI-48) found in a white filamentous community from a separate Icelandic thermal spring and the pink filaments (EM17) from Yellowstone National Park. Fluorescent in situ hybridization with clone-specific oligonucleotide probes showed that the sample analyzed was essentially a monoculture of a single phylotype.

Geomicrobiology of subglacial ice above Lake Vostok, Antarctica.

Data from ice 3590 meters below Vostok Station indicate that the ice was accreted from liquid water associated with Lake Vostok. Microbes were observed at concentrations ranging from 2.8 x 10(3) to 3.6 x 10(4) cells per milliliter; no biological incorporation of selected organic substrates or bicarbonate was detected. Bacterial 16S ribosomal DNA genes revealed low diversity in the gene population. The phylotypes were closely related to extant members of the alpha- and beta-Proteobacteria and the Actinomycetes. Extrapolation of the data from accretion ice to Lake Vostok implies that Lake Vostok may support a microbial population, despite more than 10(6) years of isolation from the atmosphere.