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Yellowstone National Park Report

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The presence of masses of pink bacteria growing at 90° in the outflow channel in some hot springs in Yellowstone National Park was observed at least as early as 1899 (unpublished work of W. A. Setchell, cited in Brock, 1978, pp. 47-49). When Brock began his extensive microbiological studies of Yellowstone thermal areas in 1965, he also found "pink, gelatinous, stringy bacterial masses" growing at 90°C in the upper end of the runoff channel of Octopus Spring and published phase micrographs of these bacterial masses (Brock, 1978, pp. 45-46). However, Brock and his associates were never able to grow these bacteria in laboratory culture and beyond the determination of the fatty acid composition of the bacterial masses by Bauman and Simmond (1969) no other biochemical studies have been conducted with these extremely thermophilic bacteria.