Table Of ContentEVOLUTION OF
HYDROTHERMAL
ECOSYSTEMS ON
EARTH (AND MARS?)
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Ciba Foundation Symposium 202
EVOLUTION OF
HYDROTHERMAL
ECOSYSTEMS ON
EARTH (AND MARS?)
1996
JOHN WILEY & SONS
Chichester . New York . Brisbane Toronto . Singapore
I
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Ciba Foundation Symposium 202
xii+335 pages, 77 figures, 19 tables
Libmry o f Congms Cataloging-in-PublicationD ob
Evolution of hydrothermal ecosystems on Earth (and Mars?)/[edited
by] Gregory R. Bock, Jamie A. Goode.
p. cm. -+Ciba Foundation Symposium; 202)
“Symposium on Evolution of Hydrothermal Ecosystems on Earth (and
Mars?), held at the Ciba kundation, London, January 3GFebruary 1,
1996”-P.
Includes bibliographical references and indexes.
ISBN 0 471 96509 X (alk. paper)
1. Lifdrigin4ngresses. 2. Hot spring ecology- Congresses.
3. Exobiology-Congresses. I. Bock, Gregory. 11. Goode, Jamie.
111. Symposium on Evolution of Hydrothermal Ecosystems on Earth (and
Mars?) (1996: Ciba Foundation) IV Series.
QH3253963 1996 96-31351
574.5‘263-dc20 CIP
British Ljbmry Cak&g&g in Publication Da&
A catalogue record for this book is available from the British Library
ISBN 0 471 96509 X
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ATMOSPHERE
4.2 Ga
510 bars of CO,
,‘,,‘$,, H2
/’,’/.$,’
co - - - - - - - -
f -b
1 rnrn
Molecular phylogenetic studies show that the deepest branches of the ‘universal tree of
life’ are occupied by hyperthermophiles. Either life arose at high temperatures (one
possible model for this is shown above), or only the hyperthermophiles survived the
‘late heavy bombardment’ during the final stages of accretion of the Earth. Thermal
springs were abundant on the early Earth and their deposits are well known to mineral
explorers because of the contained gold, copper and other valuable metals; they are a
source of palaeobiological information that has yet to be tapped. All the indications are
that such springs also would have been abundant on Mars early in its history; their
deposits are a prime target for the exploration for former life on that planet.
Thefgure irmodij5edfrom M.J , XurreNandA .J . Hall ( 1996) The emergence of Iqefrom iron monorulphidt
bubbler at 1 snbmarine lydrothermal redox andpHfront. Journal ofthe Geological Society of London (in
prerr) .
V
Contents
Symposium on Euolution ~lydmthemalecosyskmso n Earth @ndM ars?))h eldatthe Ciba Foundation,
London)J anuary PcFebnrary 1 1996
Editors: Gregoy R. Bock (Organkeer)a nd Jamie A. Goode
This symposium was basedon aproposal made & Malcolm Walter, David Des Marais, Jack firmerand
Nan9 Hinman
K. 0. Stetter Hyperthermophiles in the history of life 1
Discussion 11
General discussion I Beehive diffusers 19
How much oxygen was there in the Archaean
atmosphere? 20
S. M. Barns, C. F. Delwiche, J. D. Palmer, S. C. Dawson, K. L. Hershberger and
N. R. Pace Phylogenetic perspectives on microbial life in hydrothermal
ecosystems, past and present 24
Distusion 32
E. L. Shock Hydrothermal systems as environments for the emergence of life 40
Discursion 52
R.W. Henley Chemical and physical context for life in terrestrial hydrothermal
systems: chemical reactors for the early development of life and hydrothermal
ecosystems 61
Dircwsion 76
D. J. Des Marais Stable light isotope biogeochemistry of hydrothermal systems 83
Ducmion 94
A. Pentecost High temperature ecosystems and their chemical interactions with
their environment 99
Discmion 108
M. R. Walter Ancient hydrothermal ecosystems on Earth: a new palaeobiological
frontier 112
Discwsion 127
vii
...
Vlll CONTENTS
N. H. Trewin The Rhynie cherts: an early Devonian ecosystem preserved by
hydrothermal activity 131
Dicmion 145
S. L. Cady and J. D. Farmer Fossilization processes in siliceous thermal springs:
trends in preservation along the thermal gradient 150
Discussion 170
R. E. Summons, L. L. Jahnke and B. R. T. Simoneit Lipid biomarkers for bacterial
ecosystems: studies of cultured organisms, hydrothermal environments and ancient
sediments 174
Dicmion 193
General discussion I1 Marine hydrothermal systems 195
A. H. Knoll and M. R.Walter The limits of palaeontological information: finding
the gold among the dross 198
Discussion 210
J. F. Huntington The role of remote sensing in finding hydrothermal mineral
deposits on Earth 214
Discusion 231
R. A. Horn Exploration strategies for hydrothermal deposits 236
Discmion 246
M. H. Cam Water on early Mars 249
Discussion 265
General discussion 111 Catastrophic fluvial systems and potential hydrothermal
systems in the ancient history of Mars 268
J. D. Farmer Hydrothermal systems on Mars: an assessment of present
evidence 273
Discmion 295
General discussion IV Martian stable isotopes: volatile evolution, climate change
and exobiological implications 300
P. C.W. Davies The transfer of viable microorganisms between planets 304
Di.rcmion 314
M. R.Walter Summing-up 318
Index of contributors 321
Subject index 325
Participants
S. M. Barns Environmental Molecular Biology, M888, Life Sciences Division, Los
Alamos National Laboratory, Los Alamos, NM 87545, USA
S. L. Cady NASA Ames Research Center, MS 239-4, Moffett Field, CA 94035-1000,
USA
M. H. Carr US Geological Survey, MS-975,345 Middlefield Road, Menlo Park, CA
94025, USA
D. Cowan Department of Biochemistry and Molecular Biology, University College
London, Gower Street, London WClE 6BT, UK
P. C. W! Davies Department of Physics and Mathematical Physics,The University of
Adelaide, Adelaide, SA 5005, Australia
D. J. Des Marais Space Science Division, NASA Ames Research Center, MS 239-4,
Moffett Field, CA 94035-1000, USA
J. D. Farmer NASA Ames Research Center, MS 239-4, Moffett Field, CA 94035-
1000, USA
W. F. Giggenbach Institute of Geological and Nuclear Sciences, PO Box 31312,
Lower Hutt, New Zealand
R.W. Henley Etheridge Henley Williams, PO Box 250, Deakin West, ACT 2600,
Australia
R. A. Horn INCO Limited, 2060 Flavelle Boulevard, Missisauga, Ontario, Canada
L5K 129
J. F. Huntington CSIRO Exploration and Mining, Mineral Mapping Technologies
Group, PO Box 136, North Ryde, NSW 2113, Australia
B. M. Jakosky Laboratory for Atmospheric and Space Physics and Department of
Geological Science, University of Colorado, Boulder, CO 80309-0392, USA
iX
x PARTICIPANTS
A. H. Knoll Botanical Museum, Harvard University, 26 Oxford Street, Cambridge,
MA 02138, USA
R. Kuzmin Vernadsky Institute of Geochemistry and Analytical Chemistry, Russian
Academy of Sciences, Kosygin Sneet 19, Moscow 177975, Russia
E. G. Nisbet Department of Geology, Royal Holloway, University of London,
Egham, Surrey,TW20 OEX, UK
R. J. Parkes Department of Geology, University of Bristol, Bristol, BS8 IRJ, UK
A. Pentecost Division of Life Sciences, King's College London, Campden Hill
Road, LondonW8 7AH, UK
C. L. Powell Department of Geology and Petroleum Geology, Meston Building,
Kings College, Aberdeen, AB9 ZUE, UK
M. J. Russell Department of Geology and Applied Geology, University of Glasgow,
Glasgow G12 8QQ UK
H. Sakai 1-4-7-1508 Seishim-cho, Edogawa-ku, Tokyo, Japan
E. L. Shock Department of Earth and Planetary Sciences and McDonnell Center
for the Space Sciences,Washington University, St Louis, MO 63130, USA
B. R.T. Simoneit College of Oceanic and Atmospheric Sciences, Oregon State
University, Corvallis, OR 97331-5503, USA
K. 0. Stetter Lehrstuhl fur Mikrobiologie, Universitat Regensburg,
Universitatstrasse3 1, D-93053 Regensburg, Germany
R. E. Summons Australian Geological Survey Organisation, GPO Box 378,
Canberra, ACT 2601, Australia
N. H. Trewin Department of Geology and Petroleum Geology, Meston Building,
Kings College, University of Aberdeen, Aberdeen AB24 3UE, UK
M. R.Walter School of Earth Sciences, Macquarie University, North Ryde, NSW
2109 and Rix & Walter Pty Ltd, 265 Murramarang Road, Bawley Point, NSW 2539,
Australia
Preface
The purpose of the meeting which lead to the production of this book was to bring
together a diverse group of specialists who have complementary skills in the search for
the earliest life on Earth, for its equivalents on Mars, and ultimately for the origin of
life.
Biologists write about ‘the universal tree of life’, and believe that they can recognise
the deepest roots of that tree, and that these are thermophilic microorganisms. Many
geochemists think that this makes sense in terms of what geologists know about the
abundance of hydrothermal systems on the early Earth and in terms of the potent
chemical reactions possible in such systems. Geologists have the opportunity and the
techniques to test these hypotheses. Despite what is sometimes thought by biologists,
there are ways for geologists to find a fossil record of the different domains or super-
kingdoms of life thought to lie near the base of the universal tree, and thus both to test
the phylogenetic hypotheses and to calibrate them against time. Well preserved rock
successions 3.5 Ga old have yielded the oldest evidence of life on Earth, and even older
successions are now known. The search for evidence of life in these successions has
barely begun, and essentially no attention has yet been paid to the hydrothermal sys-
tems that were the focus of the meeting.
Going beyond the Earth, one of the greatest exploration efforts of modern times is
the search for life elsewhere in the Universe. The SETI program, of searching for radio
signals from other civilizations, has to contend with enormous odds, given the vast-
ness of the Universe and the uncertainties of recognizing biogenic signals. The odds
may well be more in favour of discovering whether there once was, and maybe still is,
life on Mars.
The discovery of evidence of former life on Mars could be interpreted in one of two
ways: the first is that life arose on Mars independently of that on Earth. That to me
seems every bit as significant as the discovery of life in the more distant realms of the
Universe. The second possibility, in some ways even more startling, would be that
early life on Mars could be found to be indistinguishable from that on Earth, That
would re-ignite interest in the Panspermia hypothesis of Hoyle and Wikramisinge, or
give a great boost to research on self-organizing systems (which might drive evolution
in particular directions).
In a petition published in Science in 1982, Carl Sagan wrote, interuiiu, ‘We are unan-
imous in our conviction that the only significant test of the existence of extraterrestrial
intelligence is an experimental one. No a priori arguments on this subject can be com-
pelling or should be used as a substitute for an observational program’. That was a
petition in support of the SETI program, but it has equal force in the search for former
xi
