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| Titel |
Microbial Induced Mineral Formation in the Deep-Subsurface Biosphere |
| VerfasserIn |
Judith A. McKenzie  , Crisogono Vasconcelos |
| Konferenz |
EGU General Assembly 2011
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 13 (2011) |
| Datensatznummer |
250058154
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| Zusammenfassung |
| Prokaryotes, in general, have been dubbed “The Unseen Majority” and those living in the
deep subsurface have been estimated to represent approximately 30% of the Earth’s total
living biomass (Whitman et al., 1998). In fact, over a surprisingly broad range of depths,
temperatures and pressures, the deep subsurface, in both marine and continental realms, hosts
an extensive microbial population comprising the deep biosphere. Geochemists studying
cored material have long recognized that the deep-sea subsurface cannot be barren of life
because the buried sediments and rocks contain distinctive geochemical signals in the
associated pore waters and in situ mineral deposits, which are indicative of microbial
activity.
Promoted by international research drilling programs, such as IODP and ICDP, a new
understanding of this deep microbial activity is evolving with the application of
microbiologic and molecular techniques to samples cored from various depositional
environments. Biogeochemical studies clearly show fluxes of metabolic reactants and
products demonstrating that a very diverse microbial activity exists at depth. These metabolic
processes with associated reactions impact the microenvironments leading to microbial
induced mineral formation or dissolution. Although the metabolic processes employed by the
subsurface microorganisms may be similar to those of surface species, they function
under uniquely different environmental conditions. For example, the lack of light at
depth excludes photosynthesis. Thus, the subsurface microbial life is dependent on
buried energy sources or influxes of dissolved components with circulating fluids.
Also, because oxygen is rapidly depleted with depth, anaerobic processes must
dominate.
Although we are only beginning to comprehend the nature and importance of this
subsurface biosphere, it will undoubtedly be an important factor to consider when evaluating
any carbon capture and storage (CCS) program utilizing subsurface formations. Determining
how microbial communities respond to perturbations induced by the injection of CO2 in a
gaseous to supercritical state will continue to be a challenging research topic of the
future.
Whitman, W.B., D.C. Coleman, and W.J. Wiebe. 1998. Prokaryotes: The unseen majority.
Proceedings of the National Academy of Sciences of the United States of America
95:6,578–6,583. |
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