This Article Figures Only Full Text Full Text (PDF) Supporting Information Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a colleague Similar articles in this journal Similar articles in ISI Web of Science Similar articles in PubMed Alert me to new issues of the journal Add to My File Cabinet Download to citation manager Request Copyright Permission Citing Articles Citing Articles via CrossRef Citing Articles via Google Scholar Google Scholar Articles by Ventura, G. T. Articles by Schaeffer, P. Search for Related Content PubMed PubMed Citation Articles by Ventura, G. T. Articles by Schaeffer, P. Social Bookmarking                What's this?

 Previous Article  | Table of Contents |  Next Article 

PHYSICAL SCIENCES / BIOLOGICAL SCIENCES / GEOLOGY / EVOLUTION
Molecular evidence of Late Archean archaea and the presence of a subsurface hydrothermal biosphere

Gregory T. Ventura^*,, Fabien Kenig^*, Christopher M. Reddy, Juergen Schieber, Glenn S. Frysinger^¶, Robert K. Nelson, Etienne Dinel^||, Richard B. Gaines^¶, and Philippe Schaeffer^**

*Department of Earth and Environmental Sciences, University of Illinois at Chicago, M/C 186, 845 West Taylor Street, Chicago, IL 60607-7059; Department of Marine Chemistry and Geochemistry, Woods Hole Oceanographic Institution, MS#4, Woods Hole, MA 02543-1543; Department of Geological Sciences, Indiana University, 1001 East 10th Street, Bloomington, IN 47405-1405; ^¶Department of Science, U.S. Coast Guard Academy, 310 Smith Hall, New London, CT 06320-8101; ^||Earth Sciences Department, Ottawa-Carleton Geoscience Centre, University of Ottawa, Ottawa, ON, Canada K1N 6N5; and **Laboratoire de Géochimie Bio-organique, Unité Mixte de Recherche 7509 du Centre National de la Recherche Scientifique, Ecole de Chimie, Polymères et Matériaux, Université Louis Pasteur, 25 Rue Becquerel, 67200 Strasbourg, France

Edited by John M. Hayes, Woods Hole Oceanographic Institution, Falmouth, MA, and approved July 20, 2007 (received for review December 13, 2006)

Highly cracked and isomerized archaeal lipids and bacterial lipids, structurally changed by thermal stress, are present in solvent extracts of 2,707- to 2,685-million-year-old (Ma) metasedimentary rocks from Timmins, ON, Canada. These lipids appear in conventional gas chromatograms as unresolved complex mixtures and include cyclic and acyclic biphytanes, C₃₆–C₃₉ derivatives of the biphytanes, and C₃₁–C₃₅ extended hopanes. Biphytane and extended hopanes are also found in high-pressure catalytic hydrogenation products released from solvent-extracted sediments, indicating that archaea and bacteria were present in Late Archean sedimentary environments. Postdepositional, hydrothermal gold mineralization and graphite precipitation occurred before metamorphism (2,665 Ma). Late Archean metamorphism significantly reduced the kerogen's adsorptive capacity and severely restricted sediment porosity, limiting the potential for post-Archean additions of organic matter to the samples. Argillites exposed to hydrothermal gold mineralization have disproportionately high concentrations of extractable archaeal and bacterial lipids relative to what is releasable from their respective high-pressure catalytic hydrogenation product and what is observed for argillites deposited away from these hydrothermal settings. The addition of these lipids to the sediments likely results from a Late Archean subsurface hydrothermal biosphere of archaea and bacteria.

The authors declare no conflict of interest.

This article is a PNAS Direct Submission.

This article contains supporting information online at www.pnas.org/cgi/content/full/0610903104/DC1.

To whom correspondence should be addressed. E-mail: gventura{at}whoi.edu

© 2007 by The National Academy of Sciences of the USA

CiteULike    Complore    Connotea    Del.icio.us    Digg    What's this?

Current Issue | Archives | Online Submission | Info for Authors | Editorial Board | About Subscribe | Advertise | Contact | Site Map Copyright © 2007 by the National Academy of Sciences