Diversity and Physiology of Methanogenic Archaea Picture on the left are a hyperthermophilic and thermophilic methanogens Methanococcusjannaschii (85C optimal) Methanococcusigneus (88° C optimal) Methanothermus fervidus (85 C optimal) Methanothrixthermophila 60Coptimal) Picture on the right: thin section of methanogenic Archaea Methanobrevibacter ruminantium Methanosarcina barkeriDiversity and Physiology of Methanogenic Archaea Picture on the left are hyperthermophilic and thermophilic methanogens Methanococcus jannaschii (85oC optimal) Methanococcus igneus (88oC optimal) Methanothermus fervidus (85oC optimal) Methanothrix thermophila 60oC optimal) Picture on the right: thin section of methanogenic Archaea: Methanobrevibacter ruminantium Methanosarcina barkeri