Observations pertaining to the origin and ecology of microorganisms recovered from the deep subsurface of Taylorsville Basin, Virginia
作者:
T. C. Onstott,
T. J. Phelps,
F. S. Colwell,
D. Ringelberg,
D. C. White,
D. R. Boone,
J. P. Mckinley,
T. O. Stevens,
P. E. Long,
D. L. Balkwill,
W. T. Griffin,
T. Kieft,
期刊:
Geomicrobiology Journal
(Taylor Available online 1998)
卷期:
Volume 15,
issue 4
页码: 353-385
ISSN:0149-0451
年代: 1998
DOI:10.1080/01490459809378088
出版商: Taylor & Francis Group
关键词: deep subsurface;hydrocarbon reservoirs;sulfate reduction;iron reduction;phospholipid fatty acid
数据来源: Taylor
摘要:
To understand the conditions under which microorganisms exist in deep hydrocarbon reservoirs, sidewall cores were collected from a natural gas‐bearing formation, 2800 m below the surface in Taylorsville Basin, Virginia. Data from chemical and microbial tracers and controls indicate that the interiors of some sidewall cores contained microorganisms indigenous to the rock formation. The cultured microorganisms were composed primarily of saline‐tolerant, thermophilic fermenting, Fe(III)‐reducing, and sulfate‐reducing bacteria (1 to 104cells/g). The physiological capabilities of the cultured microorganisms are compatible with the temperature (76°C), pressure (32 MPa), and salinity (≈0.8 wt.% NaCl equivalent) in the sampled interval. The petrological data indicated that the strata contain intercrystalline pores of micrometer size, that occur between late diagenetic cement in siltstone and within cross‐cutting, mineralized fractures in shale. These pores made up only 0.04% of the rock volume, were mostly gas‐filled, and were interconnected by pore throats with diameters <0.04 μm. Because the pore throats are smaller than known bacteria, the cultured microorganisms were probably trapped within the larger pores containing alkaline, brackish, formation water. The total phospholipid fatty acid concentration of the rock samples yielded a cellular concentration equivalent to 4 x 105cells/g, much greater than had been determined by enumeration of the cultured bacteria. This may have resulted from either inhibition of dephosphorolation reactions within pores filled with reduced gases, such as methane, or the inability to culture >0.1% of the viable bacteria. The recovery of living bacteria from such an austere environment represents one of the most remarkable examples of microbial survival yet reported.
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