Biodiversity of methanogenic and other archaea in the permanently frozen Lake Fryxell, Antarctica

Abstract

Archaea were detected in molecular diversity studies of the permanently frozen Lake Fryxell, Antarctica. Two clusters of methanogens were detected in the sediments, and another cluster of possibly methanotrophic Euryarchaeota was detected in the anoxic water column just above the sediments. One crenarchaeote was detected in water just below the oxycline. The Archaea present in Lake Fryxell are likely involved in the major biogeochemical cycles that occur there.

FIG. 1.

Geochemistry of Lake Fryxell. Methane data were obtained from reference . Salinity in Lake Fryxell ranges from 0.1 to 0.66% NaCl from 6 to 18 m (18).

FIG. 2.

Phylogenetic tree of 16S rRNA genes obtained using archaeon-specific primers on bulk DNA from the water column and sediments of Lake Fryxell. The tree is based on 621 nucleotide positions of the 16S rRNA gene, using the Kimura two-parameter distance measure in a heuristic search. All designations beginning with LF are from Lake Fryxell. Relevant environmental clone sequences from other studies are included. GenBank accession numbers are in parentheses. Bootstrap values of >50% based on 100 replicates are represented. Red, water column clones; green, sediment clones; orange, other environmental sequences. Depths from which clones were obtained: LFAc1, 11 m; LFAc2, -3, -5, -8 and -9, 14 m; LFAc4, -6, and -7, 17 m.