Figure 2.

Frequency plot of the G + C content (%) of random shotgun sequence reads (Sanger) obtained from archaeal habitats in Yellowstone National Park (YNP). Phylogenetic classification of each sequence (∼800 bp) was performed using MEGAN (“blastx”), which shows the predominant populations that contribute to metagenome sequence in these environments (dark-gray = total reads, pink = domain Archaea (shown in sites OSP_8 and JCHS_4 only), yellow = Sulfolobaceae (identity to Sulfolobus sp. also shown), red = Metallosphaera sp., green = Aeropyrum pernix, violet = Euryarchaeota, light-gray = Thermoproteaceae, dark-blue = Caldivirga sp., light-blue = Pyrobaculum sp.). Site WS_18 is shown in Figure A1 in Appendix.