Denizens of the Deep

Document Type

Book Section

Publication Date


Publication Title

The Microbiology of the Terrestrial Deep Subsurface


CRC Press

Publisher Location

Boca Raton

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Subsurface microbial presence and involvement in geochemical transformations was reported decades ago (Farrell and Turner, 1931; Kuznetsov et al., 1963; Lipman, 1931), and an acceleration in subsurface research has occurred over the last decade. Much of this research has been collaborative and interdisciplinary, involving the efforts of microbiologists, geochemists, hydrologists, drilling and mining experts, as well as program support, and has thus facilitated rapid progress. A primary incentive has been the potential for microbiota to clean up contaminated underground environments for the protection or purification of water supplies through bioremediation (Ghiorse and Wilson, 1988; Madsen and Ghiorse, 1993; Balkwill et al., 1994). Not long ago most scientists firmly believed that life was absent below some fairly shallow threshold depth (Ghiorse and Wilson, 1988). Microbiota have now been recovered at depths greater than 9000 ft below the surface (Boone et al., 1995). Additionally, investigations of deep ocean sediments indicate that they are teeming with microbial life (Parks et al., 1994). Microorganisms have been investigated in both shallow and deep aquifer systems and associated sediments (Balkwill and Ghiorse, 1985; Hirsch, 1992). Sampling techniques have included both drilling/coring procedures, and mining in rock, ore, and salt deposits (see Chapters 3 and 4). European, Canadian, and American scientists have also studied the microbiology of the terrestrial subsurface for the practical reason that radioactive and other waste repositories are often built underground and microbes inhabiting those environments may impact the integrity of the waste storage facilities (see Chapters 15 and 16, and Proceedings of the 7th Annual International High Level Radioactive Waste Management Meetings, Las Vegas, 1996).





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