Hostname: page-component-586b7cd67f-t7fkt Total loading time: 0 Render date: 2024-11-23T00:01:32.361Z Has data issue: false hasContentIssue false
  • English
  • Français

On the forcing mechanism for the H2-driven deep biosphere

Published online by Cambridge University Press:  08 July 2008

Helge Hellevang
Helge Hellevang
Affiliation:
Center for Geobiology at Department of Earth Sciences, University of Bergen, Allègaten 41, 5007 Bergen, Norway e-mail: [email protected]
Get access Rights & Permissions [Opens in a new window]

Abstract

Heat produced in the mantle and core of the Earth by the decay of radioactive elements and mineral fusion results in large-scale mantle convection. The outer shell of the Earth that floats on the convective mantle is divided into rigid lithospheric plates. Subduction of dense cold plates into the mantle leads to plate tectonics. At divergent plate margins, heat is dissipated through hydrothermal convection cells. As ocean water is entrained into hydrothermal cells it interacts with fresh magmatic rocks and liberates ferrous iron. This iron reduces the ocean water to such an extent that it decomposes and forms hydrogen. Molecular hydrogen, as the most reduced component in the system, forms a basal component to a deep dark biosphere powered by metastable redox gradients. In this paper we review the driving force behind a hydrogen-driven deep biosphere. We present abundant observations of hydrogen produced at natural hydrothermal settings as well as in laboratory experiments. The key mineral reactions responsible for the bulk of this hydrogen production are then presented. A division of the reaction progression into an oxidized state and a reduced state is suggested. The amount of hydrogen produced is insignificant in the oxidized state whereas it becomes proportional to the amount of ferrous iron oxidized in the reduced state. The bulk of basalt-hosted aquifers are expected to reside in the oxidized state because of the low content of ferrous minerals, whereas abundant olivine in ultramafic-hosted systems is responsible for large-scale hydrogen production. Today the majority of the seafloor is basaltic. The Archean seafloor on the other hand consisted of fewer ultramafic exposures, but was dominated by ultramafic magnesium-rich lavas with a higher potential for hydrogen production than the present seafloor.

Keywords

Hydrogendeep biosphereserpentinizationOlivinehydrothermalblack smoker
Type
Research Article
Information
International Journal of Astrobiology , Volume 7 , Issue 2 , April 2008 , pp. 157 - 167
Copyright
Copyright © 2008 Cambridge University Press

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

Abbott, D., Burgess, L., Longhi, J. & Smith, W.H.F. (1994). An empirical thermal history of the Earth's upper mantle. J. Geophys. Res. 99, 13 835–13 850.CrossRefGoogle Scholar
Alt, J.C., Teagle, D.A.H., Laverne, C., Vanko, D., Bach, W., Honnorez, J., Becker, K. & Pezard, P.A. (1996a). Ridge flank alteration of upper oceanic crust in the eastern Pacific: a synthesis of results for volcanic rocks of Holes 504B and 896A. Proc. Ocean Drill. Program: Sci. Results 148, 435–450.Google Scholar
Alt, J.C., Laverne, C., Vanko, D., Tartarotti, P., Teagle, D.A.H., Bach, W., Zuleger, E., Erzinger, J., Honnorez, J., Becker, K., Pezard, P.A., Salisbury, M. & Wilkens, R. (1996b). Hydrothermal alteration of a section of upper oceanic crust in the Eastern Equatorial Pacific: a synthesis of results from DSDP/ODP Legs 69, 70, 111, 137, 140, and 148 at Site 504. Proc. Ocean Drill. Program: Sci. Results 148, 417–434.Google Scholar
Alt, J.C. & Shanks, W.C. III (2003). Serpentinization of abyssal peridotites from the MARK area, Mid-Atlantic Ridge: sulfur geochemistry and reaction modeling. Geochim. Cosmochim. Acta 67, 641–653.CrossRefGoogle Scholar
Anderson, R.B. (1984a). The Fischer–Tropsch Synthesis. Academic Press, New York.Google Scholar
Anderson, R.B. (1984b). Forty years with the Fischer–Tropsch synthesis 1944–1984. Stud. Surf. Sci. Catalys. 19, 457–461.CrossRefGoogle Scholar
Anderson, R.T., Chapelle, F.H. & Lovley, D.R. (1998). Evidence against hydrogen-based microbial ecosystems in basalt aquifers. Science 281, 976–977.CrossRefGoogle ScholarPubMed
Anderson, R.T., Chapelle, F.H. & Lovley, D.R. (2001). Comment on “Abiotic controls on H2 production from basalt–water reactions and implications for aquifer biogeochemistry”. Env. Sci. Technol. 35, 1556–1557.CrossRefGoogle Scholar
Apel, C.L., Deamer, D.W. & Mautner, M.N. (2002). Self-assembled vesicles of monocarboxylic acids and alcohols: conditions for stability and for encapsulation of biopolymers. Biochim. Biophys. Acta 1559, 1–9.CrossRefGoogle ScholarPubMed
Bach, W. & Edwards, K.J. (2003). Iron and sulfide oxidation within basaltic oceanic crust: implications for chemolithoautotrophic microbial biomass production. Geochim. Cosmochim. Acta 67, 3871–3887.CrossRefGoogle Scholar
Bach, W., Peucker-Ehrenbrink, B., Hart, S.R. & Blusztjan, J.S. (2003). Geochemistry of hydrothermally altered oceanic crust: DSDP/ODP Hole 504B – implications for seawater – crust exchange budgets and Sr- and Pb-isotopic evolution of the mantle. Geochem. Geophys. Geosyst. 4, DOI:10.1029/2002GC000419.Google Scholar
Bach, W., Paulick, H., Garrido, C.J., Ildefonse, B., Meurer, W.P. & Humphris, S.E. (2006). Unraveling the sequence of serpentinization reactions: petrography, mineral chemistry, and petrophysics of serpentinites from MAR 15°N (ODP Leg 209, Site 1274). Geophys. Res. Let. 33, L13306, doi:10.1029/2006GL025681, 1–4.CrossRefGoogle Scholar
Baross, J.A. & Deming, J.W. (1985). The role of bacteria in the ecology of black-smoker environments. Biol. Soc. Wash. Bull. 6, 355–371.Google Scholar
Bercovici, D. (2003). The generation of plate tectonics from mantle convection. Earth Planet. Sci. Lett. 205, 107–121.CrossRefGoogle Scholar
Binns, R.A. & Scott, S.D. (1993). Actively forming polymetallic sulfide deposits associated with felsic volcanic rocks in the eastern Manus back-arc basin, Papua New Guinea. Econ. Geol. 88, 2226–2236.CrossRefGoogle Scholar
Canil, D. (2002). Vanadium in peridotites, mantle redox and tectonic environments: Archean to present. Earth Planet. Sci. Lett. 195, 75–90.CrossRefGoogle Scholar
Catling, D.C. & Claire, M.W. (2005). How Earth's atmosphere evolved to an oxic state: a status report. Earth Planet. Sci. Lett. 237, 1–20.CrossRefGoogle Scholar
Chapelle, F.H., O'Neill, K., Bradley, P.M., Methé, B.A., Ciufo, S.A., Knobel, L.L. & Lovley, D.R. (2002). A hydrogen-based subsurface microbial community dominated by methanogens. Nature 415, 312–315.CrossRefGoogle ScholarPubMed
Charlou, J.L., Donval, J.P., Fouquet, Y., Jean-Baptiste, P. & Holm, N. (2002). Geochemistry of high H2 and CH4 vent fluids issuing from ultramafic rocks at the Rainbow hydrothermal field (36°14′N, MAR). Chem. Geol. 191, 345–359.CrossRefGoogle Scholar
Condie, K.C. (1997). Crustal and mantle evolution. In Plate Tectonics and Crustal Evolution, Chapter 5. Butterworth-Heinemann, Oxford.Google Scholar
Connelly, D.P., German, C.R., Asada, M., Okino, K., Egorov, A., Naganuma, T., Pimenov, N., Cherkashev, G. & Tamaki, K. (2007). Hydrothermal activity on the ultra-slow spreading southern Knipovich Ridge. Geochem. Geophys. Geosys. 8, Q08013, doi:10.1029/2007GC001652.CrossRefGoogle Scholar
Corliss, J.B., Dymond, J., Gordon, L.I., Edmond, J.M., von Herzen, R.P., Ballard, R.D., Green, K., Williams, D., Bainbridge, A., Crane, K. & van Andel, T.H. (1979). Submarine thermal sprirngs on the Galápagos Rift. Science 203, 1073–1083.CrossRefGoogle ScholarPubMed
Cowen, J.P., Giovannoni, S.J., Kenig, F., Johnson, H.P., Butterfield, D., Rappé, M.S., Hutnak, M. & Lam, P. (2003). Fluids from aging ocean crust that support microbial life. Science 299, 120–123.CrossRefGoogle ScholarPubMed
de Villiers, S. & Nelson, B.K. (1999). Detection of low-temperature hydrothermal fluxes by seawater Mg and Ca anomalies. Science 285, 721–723.CrossRefGoogle Scholar
Dick, H.J.B., Lin, J. & Schouten, H. (2003). An ultraslow-spreading class of ocean ridge. Nature 426, 405–412.CrossRefGoogle ScholarPubMed
Dilek, Y., Coulton, A. & Hurst, S.D. (1997). Serpentinization and hydrothermal veining in peridotites at site 920 in the Mark area. In Proc. Ocean Drilling Program, Scientific Results, vol. 153, eds Karson, J.A., Cannat, M., Miller, D.J. & Elthon, D., pp. 35–59.Google Scholar
Durrheim, R.J. & Mooney, W.D. (1994). Evolution of the Precambrian lithosphere: seismological and geochemical constraints. J. Geophys. Res. 99, 15 359–15 374.CrossRefGoogle Scholar
Edmonds, H.N., Michael, P.J., Baker, E.T., Connelly, D.P., Snow, J.E., Langmuir, C.H., Dick, H.J.B., Mühe, R., German, C.R. & Graham, D.W. (2003). Discovery of abundant hydrothermal venting on the ultraslow-spreading Gakkel ridge in the Arctic Ocean. Nature 421, 252–256.CrossRefGoogle ScholarPubMed
Fischer, F. & Tropsch, H. (1923). Preparation of synthetic oil mixtures (synthol) from carbon monoxide and hydrogen. I. Brennstoff-Chem. 4, 276–285.Google Scholar
Fliermans, C.B. (1989). Microbial life in the terrestrial subsurface of southeastern coastal plain sediments. Hazard. Waste Hazard. Mater. 6, 155–175.CrossRefGoogle Scholar
Fliermans, C.B. & Balkwill, D.L. (1989). Microbial life in deep terrestrial subsurfaces. Bioscience 39, 370–377.CrossRefGoogle Scholar
Früh-Green, G.L., Plas, A. & Dell Angelo, L.N. (1996a). Mineralogic and stable-isotope record of polyphase alteration of upper crustal gabbros of the East Pacific Rise (Hess Deep, Site 894). In Proc. Ocean Drilling Program, Scientific Results, vol. 147, eds Mével, C., Gillis, K.M., Allan, J.F. & Meyer, P.S.Google Scholar
Früh-Green, G.L., Plas, A. & Lécuyer, C. (1996b). Petrologic and stable isotope constraints on hydrothermal alteration and serpentinization of the EPR shallow mantle at Hess Deep (Site 895). In Proc. Ocean Drilling Program, Scientific Results, vol. 147, eds Mével, C., Gillis, K.M., Allan, J.F. & Meyer, P.S.Google Scholar
Früh-Green, G.L., Kelley, D.S., Bernasconi, S.M., Karson, J.A., Ludwig, K.A., Butterfield, D.A., Boschi, C. & Proskurowski, G. (2003). 30,000 years of hydrothermal activity at the Lost City vent field. Science 301, 495–498.CrossRefGoogle Scholar
Fu, Q., Seyfried, W.E. Jr. & Horita, J. (2004). Hydrothermal carbon dioxide reduction with magnetite at 400C and 500 bar. In Proc. 11th Int. Symp. on Water–Rock Interaction, eds Wanty, R.B. & Seal, R.R.I., pp. 1285–1288. A.A. Balkema, Lisse.Google Scholar
Furnes, H. & Staudigel, H. (1999). Biological mediation in ocean crust alteration: how deep is the deep biosphere? Earth Planet. Sci. Lett. 166, 97–103.CrossRefGoogle Scholar
German, C.R. & Von Damm, K.L. (2003). Hydrothermal processes. In Treatise on Geochemistry, vol. 6, eds Holland, H.D. & Turekian, K.K., pp. 181–222.CrossRefGoogle Scholar
German, C.R., Lin, J. & Parson, L.M. (eds) (2004). Mid-Ocean Ridges: Hydrothermal Interactions between the Lithosphere and Oceans (AGU Geophysical Monograph, no. 148). American Geophysical Union, Washington, DC.CrossRefGoogle Scholar
Hinrichs, K.-U., Hayes, J.M., Sylva, S.P., Brewer, P.G. & DeLong, E.F. (1999). Methane-consuming archaebacteria in marine sediments. Nature 398, 802–805.CrossRefGoogle ScholarPubMed
Hoffmeister, A.M. & Criss, R.E. (2005). Earth's heat flux revised and linked to chemistry. Tectonophysics 395, 159–177.CrossRefGoogle Scholar
Holm, N.G. & Charlou, J.L. (2001). Initial indications of abiotic formation of hydrocarbons in the Rainbow ultramafic hydrothermal system, Mid-Atlantic Ridge. Earth Planet. Sci. Lett. 191, 1–8.CrossRefGoogle Scholar
Jiménez, L. (1990). Molecular analysis of deep-subsurface bacteria. Appl. Environ. Microbiol. 56, 2108–2113.CrossRefGoogle ScholarPubMed
Jones, H.H. (2004). Redox conditions among the terrestrial planets. In Proc. 35th Lunar and Planetary Science Conf., 15–19 March 2004, Houston, TX.Google Scholar
Junge, K., Eicken, H. & Deming, J.W. (2004). Bacterial activity at −2 to −20°C in Arctic wintertime sea ice. Appl. Environ. Microbiol. 70, 550–557.CrossRefGoogle Scholar
Karson, J.A., Cannat, M., Miller, D.J. & Elthon, D. (eds) (1997). Proc. Ocean Drilling Program, Scientific Results, vol. 153.Google Scholar
Karson, J.A. (2001). Oceanic crust when Earth was young. Science 292, 1076–1079.CrossRefGoogle ScholarPubMed
Karson, J.A. (2002). Geologic structure of upper-most oceanic crust from fast- to intermediate-rate mid-ocean ridges. Annu. Rev. Earth Planet. Sci. 30, 347–384.CrossRefGoogle Scholar
Kashefi, K. & Lovley, D.R. (2003). Extending the upper temperature limit for life. Science 301, 934.CrossRefGoogle ScholarPubMed
Kasting, J.F. (1993). Earth's early atmosphere. Science 259, 920–926.CrossRefGoogle ScholarPubMed
Kearey, P. & Vine, F.J. (1996). Global Tectonics, 2nd edn. Blackwell, London.Google Scholar
Kelley, D.S., Karson, J.A., Blackman, D.K., Früh-Green, G.L., Butterfield, D.A., Lilley, M.D., Olson, E.J., Schrenk, M.O., Roe, K.K., Lebon, G.T., Rivizzigno, P. & the AT3-60 Shipboard Party (2001). An off-axis hydrothermal vent field near the Mid-Atlantic Ridge at 30° N. Nature 412, 145–149.CrossRefGoogle ScholarPubMed
Kelley, D.S. et al. (2005). A serpentinite-hosted ecosystem: the Lost City hydrothermal field. Science 307, 1428–1434.CrossRefGoogle ScholarPubMed
Kimura, H., Asada, R., Masta, A. & Naganuma, T. (2003). Distribution of microorganisms in the subsurface of the Manus Basin Hydrothermal Vent Field in Papua New Guinea. Appl. Environ. Microbiol. 69, 644–648.CrossRefGoogle ScholarPubMed
Kormas, K.A., Smith, D.C., Edgcomb, V. & Teske, A. (2003). Molecular analysis of deep subsurface microbial communities in Nankai Trough sediments (ODP Leg 190, Site 1176). FEMS Microbiol. Ecol. 45, 115–125.CrossRefGoogle ScholarPubMed
Kotelnikova, S. & Pedersen, K. (1997). Evidence for methanogenic Archaea and homoacetogenic Bacteria in deep granitic rock aquifers. FEMS Microbiol. Rev. 20, 339–349.CrossRefGoogle Scholar
Kral, T., Brunk, K.M., Miller, S.L. & McKay, C.P. (1998). Hydrogen consumption by methanogens on the early Earth. Origin. Life Evol. Biosph. 28, 311–319.CrossRefGoogle ScholarPubMed
Kump, L.R. & Barley, M.E. (2007). Increased subaerial volcanism and the rise of atmospheric oxygen 2.5 billion years ago. Nature 448, 1033–1036.CrossRefGoogle ScholarPubMed
Langmuir, C.H., Klein, E.M. & Plank, T. (1992). Petrological systematics of mid-ocean ridge basalts: constraints on melt generation beneath ocean ridges. Geophys. Monogr. 71, 183–280.Google Scholar
Laverne, C., Agrinier, P., Hermitte, D. & Bohn, M. (2001). Chemical fluxes during hydrothermal alteration of a 1200-m long section of dikes in the oceanic crust, DSDP/ODP Hole 504B. Chem. Geol. 181, 73–98.CrossRefGoogle Scholar
Li, Z.-X.A. & Lee, C.-T.A. (2004). The constancy of upper mantle fO2 through time inferred from V/Sc ratios in basalts. Earth Planet. Sci. Lett. 228, 483–493.Google Scholar
Lonsdale, P. (1977). Clustering of suspension-feeding macrobenthos near abyssal hydrothermal vents at oceanic spreading centers. Deep-Sea Res. 24, 857–863.CrossRefGoogle Scholar
Lowell, R.P. & Rona, P.A. (2002). Seafloor hydrothermal systems driven by the serpentinization of peridotite. Geophys. Res. Let. 29, 1–5.CrossRefGoogle Scholar
Lysnes, K., Torsvik, T., Thorseth, I.H. & Pedersen, R.B. (2004). Microbial populations in ocean floor basalt: results from ODP Leg 187. In Proceedings of the Ocean Drilling Program, Scientific Results, vol. 187, eds Pedersen, R.B., Christie, D.M. & Miller, D.J.Google Scholar
Marion, G.M., Fritsen, C.H., Eicken, H. & Payne, M.C. (2003). The search for life on Europa: limiting environmental factors, potential habitats, and Earth analogues. Astrobiology 3, 785–811.CrossRefGoogle ScholarPubMed
McCammon, C. (2005). The paradox of mantle redox. Science 308, 807–808.CrossRefGoogle ScholarPubMed
McCollom, T.M., Ritter, G. & Simoneit, B.R.T. (1999). Lipid synthesis under hydrothermal conditions by Fischer–Tropsch-Type reactions. Orig. Life Evol. Biosph. 29, 153–166.CrossRefGoogle ScholarPubMed
McCollom, T.M. & Seewald, J.S. (2006). Carbon isotope composition of organic compounds produced by abiotic synthesis under hydrothermal conditions. Earth Planet. Sci. Lett. 243, 74–84.CrossRefGoogle Scholar
Mével, C. (2003). Serpentinization of abyssal peridotites at mid-ocean ridges. C. R. Geosci. 335, 825–852.Google Scholar
Milner-White, E.J. & Russell, M.J. (2008). Predicting the conformations of peptides and proteins in early evolution. Biology Direct 3, doi:10.1186/1745-6150-3-3.CrossRefGoogle ScholarPubMed
Moody, J.B. (1976). Serpentinizaion: a review. Lithos 9, 125–138.CrossRefGoogle Scholar
Nealson, K.H., Inagaki, F. & Takai, K. (2005). Hydrogen-driven subsurface lithoautotrophic microbial ecosystems (SLIMEs): do they exist and why should we care? TRENDS Microbiol. 13, 405–410.CrossRefGoogle ScholarPubMed
Ogawa, M. (2007). Mantle convection: a review. Fluid Dyn. Res., doi:10.1016/j.fluiddyn.2007.09.001.Google Scholar
O'Neill, C., Jellinek, A.M. & Lenardic, A. (2007). Conditions for the onset of plate tectonics on terrestrial planets and moons. Earth Planet. Sci. Lett. 261, 20–32.CrossRefGoogle Scholar
Oze, C. & Sharma, M. (2007). Serpentinization and the inorganic synthesis of H2 in planetary surfaces. Icarus 186, 557–561.CrossRefGoogle Scholar
Parkes, R.J., Cragg, B.A., Bale, S.J., Getliff, J.M., Goodman, K., Rochelle, P.A., Fry, J.C., Weightman, A.J. & Harvey, S.M. (1994). Deep bacterial biosphere in Pacific Ocean sediments. Nature 371, 410–413.CrossRefGoogle Scholar
Pedersen, K. (2001). Diversity and activity of microorganisms in deep igneous rock aquifers of the Fennoscandian Shield. In Subsurface Microbiology and Biochemistry, eds Fredrickson, J.K. & Fletcher, M., pp. 97–139. Wiley–Liss, New York.Google Scholar
Pedersen, R.B., Thorseth, I.H., Hellevang, B., Schultz, A., Taylor, P., Knudsen, H.P. & Steinsbu, B.O. (2005). Two vent fields discovered at the ultraslow spreading Arctic Ridge System. In Proc. AGU Fall Meeting 05, 5–9 December 2005, San Fransisco, CA.Google Scholar
Pedersen, R.B., Thorseth, I.H., Olson, E., Hellevang, H., Okland, I., Baumberger, T., Lilley, M., Bruvoll, V., Mjelde, R. & Haflidason, H. (2007). Hydrothermal activity and core complex formation at the Arctic Mid-Ocean Ridge: an overview of preliminary results of the H2DEEP expedition to the southern Knipovich Ridge at 73N. In Proc. AGU Fall Meeting 07, 10–14 December 2007, San Fransisco, CA.Google Scholar
Pedersen, R.B., Barriga, F., Escartin, J., Früh-Green, G., MacLeod, C., Mjelde, R. & Thorseth, I. (2008). Ultra-slow spreading and hydrogen-based deep biosphere: objectives and preliminary results from the H2DEEP project. In Proc. EGU General Assembly, 13–18 April 2008, Vienna, Austria (Geophys. Res. Abstracts, no. 10).Google Scholar
Pokrovsky, O.S. & Schott, J. (2000). Kinetics and mechanism of forsterite dissolution at 25°C and pH from 1 to 12. Geochim. Cosmochim. Acta. 64, 3313–3325.CrossRefGoogle Scholar
Proskurowski, G., Lilley, M.D., Kelley, D.S. & Olsen, E. (2006). Low temperature volatile production at the Lost City hydrothermal field, evidence from a hydrogen stable isotope geothermometer. Chem. Geol. 229, 331–343.CrossRefGoogle Scholar
Proskurowski, G., Lilley, M.D., Seewald, J.S., Früh-Green, G.L., Olson, E.J., Lupton, J.E., Sylva, S.P. & Kelley, D.S. (2008). Abiogenic hydrocarbon production at Lost City hydrothermal field. Science 319, 604–607.CrossRefGoogle ScholarPubMed
Rama Murthy, V., van Westrenen, W. & Fei, Y. (2003). Experimental evidence that potassium is a substantial radioactive heat source in planetary cores. Nature 423, 163–165.CrossRefGoogle Scholar
Roussel, E.G., Cambon bonavita, M.-A., Querellou, J., Cragg, B.A., Webster, G., Prieur, D. & Parkes, R.J. (2008). Extending the sub-seafloor biosphere. Science 320, 1046.CrossRefGoogle Scholar
Rouxel, O.J., Bekker, A. & Edwards, K.J. (2005). Iron isotope constraints on the Archean and Paleoproterozoic ocean redox state. Science 307, 1088–1091.CrossRefGoogle ScholarPubMed
Rowley, D.B. (2002). Rate of plate creation and destruction: 180 Ma to present. Geol. Soc. Am. Bull. 114, 927–933.2.0.CO;2>CrossRefGoogle Scholar
Rushdi, A.I. & Simoneit, B.R.T. (2001). Lipid formation by aqueous Fischer–Tropsch-Type synthesis over a temperature range of 100 to 400°C. Origin. Life Evol. Biosph. 31, 103–118.CrossRefGoogle Scholar
Russell, M.J. (2007). The alkaline solution to the emergence of life: energy, entropy and early evolution. Acta Biotheor. 55, 133–179.CrossRefGoogle Scholar
Schippers, A., Neretin, L.N., Kallmeyer, J., Ferdelman, T.G., Cragg, B.A., Parkes, J.R. & Jørgensen, B.B. (2005). Prokaryotic cells of the deep sub-seafloor biosphere identified as living bacteria. Nature 433, 861–864.CrossRefGoogle ScholarPubMed
Schippers, A. & Neretin, L.N. (2006). Quantification of microbial communities in near-surface and deeply buried marine sediments on the Peru continental margin using real-time PCR. Environ. Microbiol. 8, 1251–1260.CrossRefGoogle ScholarPubMed
Schleper, C., Pühler, G., Kühlmorgen, B. & Zillig, W. (1995). Life at extremely low pH. Nature 375, 741–742.CrossRefGoogle ScholarPubMed
Schulte, M., Blake, D., Hoehler, T. & McCollom, T. (2006). Serpentinization and its implications for life on the early Earth and Mars. Astrobiology 6, 364–376.CrossRefGoogle ScholarPubMed
Seyfried, W.E. Jr., Foustoukos, D.I. & Fu, Q. (2007). Redox evolution and mass transfer during serpentinization: an experimental and theoretical study at 200°C and 500 bar with implications for ultramafic-hosted hydrothermal systems. Geochim. Cosmochim. Acta 71, 3872–3886.CrossRefGoogle Scholar
Shock, E.L. (1990). Geochemical constraints on the origin of organic compounds in hydrothermal systems. Orig. Life Evol. Biosph. 20, 331–367.CrossRefGoogle Scholar
Simoneit, B.R.T. (2004). Prebiotic organic synthesis under hydrothermal conditions: an overview. Adv. Space Res. 33, 88–94.CrossRefGoogle Scholar
Simoneit, B.R.T., Rushdi, A.I. & Deamer, D.W. (2007). Abiotic formation of acylglycerols under simulated hydrothermal conditions and self-assembly properties of such lipid products. Adv. Space Res. 40, 1649–1656.CrossRefGoogle Scholar
Sleep, N.H., Meibom, A., Fridriksson, Th., Coleman, R.G. & Bird, D.K. (2004). H2-rich fluids from serpentinization: Geochemical and biotic implications. Proc. Natl. Acad. Sci. U.S.A. 101, 12 818–12 823.CrossRefGoogle ScholarPubMed
Spear, J.R., Walker, J.J., McCollom, T.M. & Pace, N.R. (2005). Hydrogen and bioenergetics in the Yellowstone geothermal ecosystem. Proc. Natl. Acad. Sci. U.S.A. 102, 2555–2560.CrossRefGoogle ScholarPubMed
Staudigel, H., Plank, T., While, B. & Schmincke, H.-U. (1996). Geochemical fluxes during seafloor alteration of the basaltic upper oceanic crust: DSDP Sites 417 and 418. In Subduction Top to Bottom, eds Bebout, G.E., Scholl, D.W., Kirby, S.H. & Platt, J.P. (Geophysics Monographs, vol. 96), pp. 19–38. American Geophysical Union, Washington, DC.Google Scholar
Steiner, S.A. & Conrad, C.P. (2007). Does active mantle upwelling help drive plate motions? Phys. Planet. Inter. 161, 103–114.CrossRefGoogle Scholar
Stevens, T.O. & McKinley, J.P. (1995). Lithoautotrophic microbial ecosystems in deep basalt aquifers. Science 270, 450–454.CrossRefGoogle Scholar
Stevens, T. (1997). Lithoautotrophy in the subsurface. FEMS Microb. Rev. 20, 327–337.CrossRefGoogle Scholar
Stevens, T.O. & McKinley, J.P. (2000). Abiotic controls on H2 production from basalt–water reactions and implications for aquifer biogeochemistry. Environ. Sci. Technol. 34, 826–831.CrossRefGoogle Scholar
Sudarikov, S.M. & Roumiantsev, A.B. (2000). Structure of hydrothermal plumes at the Logatchev vent field, 14°45′N, Mid-Atlantic Ridge: evidence from geochemical and geophysical data. J. Volc. Geotherm. Res. 101, 245–252.CrossRefGoogle Scholar
Tarasov, V.G., Gebruk, A.V., Mironov, A.N. & Moskalev, L.I. (2005). Deep-sea and shallow-water hydrothermal vent communities: two different phenomena? Chem. Geol. 224, 5–39.CrossRefGoogle Scholar
Teske, A., Ashita, D. & Sogin, M.L. (2003). Genomic markers of ancient anaerobic microbial pathways: sulfate reduction, methanogenesis, and methane oxidation. Biol. Bull. 204, 186–191.CrossRefGoogle ScholarPubMed
Toffin, L., Webster, G., Weightman, A.J., Fry, J.C. & Prieur, D. (2004). Molecular monitoring of culturable bacteria from deep-sea sediment of the Nankai Trough, Leg 190 Ocean Drilling Program. FEMS Microbiol. Ecol. 48, 357–367.CrossRefGoogle ScholarPubMed
Torsvik, V. & Øvreås, L. (2008). Microbial diversity, life strategies, and adaption to life in extreme soils. In Microbiology of Extreme Soils. Soil Biology, eds Dion, P. & Nautiyal, C.S., pp. 15–43. Springer, Berlin.CrossRefGoogle Scholar
Tsukahara, H., Imai, E.I., Honda, H., Hatori, K. & Matsuno, K. (2002). Prebiotic oligomerization on or inside lipid vesicles in hydrothermal environments. Orig. Life Evol. Biosph. 32, 13–21.CrossRefGoogle ScholarPubMed
Van Dover, C.L. (2000). The Ecology of Deep-sea Hydrothermal Vents. Princeton University Press, Princeton, NJ.CrossRefGoogle Scholar
Ventosa, A., Arahal, D.R. & Volcani, B.E. (1999). Studies on the microbiota of the Dead Sea – 50 years later. In Microbiology and Biogeochemistry of Hypersaline Environments, ed. Oren, A., pp. 139–147. CRC Press, Boca Raton, FL.Google Scholar
Viljoen, M.J. & Viljoen, R.P. (1969). The geology and geochemistry of the lower ultramafic unit of the Onverwacht Group and a proposed new class of igneous rocks. In Proc. Upper Mantle Project, South African National Committee Symp. (Geological Society South Africa Special Publication, vol. 2), pp. 55–85.Google Scholar
Wiechert, U.H. (2002). Earth's early atmosphere. Science 298, 2341–2342.CrossRefGoogle ScholarPubMed
Wilson, D.S. et al. (2006). Drilling to gabbro in intact ocean crust. Science 312, 1016–1020.CrossRefGoogle ScholarPubMed
Wortmann, U.G., Chernyavsky, B., Bernasconi, S.M., Brunner, B., Böttcher, M.E. & Swart, P.K. (2007). Oxygen isotope biogeochemistry of pore water sulfate in the deep biosphere: dominance of isotope exchange reactions with ambient water during microbial sulfate reduction (ODP Site 1130). Geochim. Cosmochim. Acta. 71, 4221–4232.CrossRefGoogle Scholar