of Archaea in Marine Sediments from Skan Bay, Alaska,
Including Cultivated Methanogens, and Description of Methanogenium
boonei sp. nov.
Melissa M. Kendall,1* George D. Wardlaw,2
Chin F. Tang,1 Adam S. Bonin,1, Yitai
Liu,1 and David L. Valentine3
University of Texas Southwestern Medical Center, Department
of Microbiology, 5323 Harry Hines Blvd., Dallas, TX 75390-9048.
Methanogenesis in cold marine sediments
is a globally important process leading to methane hydrate
deposits, cold seeps, physical instability of sediment,
and atmospheric methane emissions. We employed a multidisciplinary
approach that combined culture-dependent and -independent
analyses with geochemical measurements in the sediments
of Skan Bay, Alaska (53°N, 167°W), to investigate
methanogenesis there. Cultivation-independent analyses of
the archaeal community revealed that uncultivated microbes
of the kingdoms Euryarchaeota and Crenarchaeota
are present at Skan Bay and that methanogens constituted
a small proportion of the archaeal community. Methanogens
were cultivated from depths of 0 to 60 cm in the sediments,
and several strains related to the orders Methanomicrobiales
and Methanosarcinales were isolated. Isolates were
psychrotolerant marine-adapted strains and included an aceticlastic
methanogen, strain AK-6, as well as three strains of CO2-reducing
methanogens: AK-3, AK7, and AK-8. The phylogenetic positions
and physiological characteristics of these strains are described.
We propose a new species, Methanogenium boonei,
with strain AK-7 as the type strain.
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