Morphological Biosignatures and the Search for Life on Mars
"Determining the location of potential paleobiological repositories
on Mars requires an understanding of the martian surface in
terms of elemental abundances and mineralogy. This variety
of hematite on Earth forms only in the presence of large amounts of
water, and typically at elevated (hydrothermal) temperatures
(Christensen et al., 2000)."
http://geology.asu.edu/jfarmer/pubs/pdfs/morpho.pdf
"It is this common association of microbes and iron
deposition on earth that has spurred hopes that robot
crafts exploring the hematite anomaly of Mars' Meridiani
Planum might find evidence for ancient life. The
hematite deposits of Meridiani Planum [7], regardless of
their exact origin, are considered to be a favorable host
for microorganisms that might have been associated
with their formation [8]."
http://www.lpi.usra.edu/meetings/lpsc2004/pdf/1369.pdf
The Stromatolites of Stella Maris, Bahamas
http://www.theflyingcircus.com/stella_maris.html
Endurance Crater
http://marsrovers.jpl.nasa.gov/gallery/all/1/n/119/1N138744629EFF2809P1987R0M1.JPGhttp://marsrovers.jpl.nasa.gov/gallery/all/1/n/111/1N138039382EFF2600P1986R0M1.HTML
Microbolites in the Geologic Record
"Whereas internal morphology indicates the accretionary nature of stromatolite
growth, the external morphology of stromatolites can be used to infer hydrological
conditions in the environment in which the stromatolites grew. For instance, in
still-water environments, stromatolites will approximate a flat sheet, while in
more turbulent environments the stromatolites will consist of interlinked domes
or columns, with flat, linking mats between them."
http://www.geocities.com/earthhistory/newstrom.htm
Lamination as a tool for distinguishing microbial and metazoan
biosystems from inert structures
Conclusion:
"Lamination often indicates the presence of microbial or microbially
dominated biosystems. Furthermore, laminated structures are an
important borderline to distinguish micro and macroorganisms, although
such a distinction is relative. Both the presence and absence of
lamination are lawful phenomena based on the fundamental physical and
biological/biogeochemical principles."
http://www.lpi.usra.edu/lpi/scholz.pdf
Introduction
"At all scales of observation, problems often arise when trying
to distinguish between biological and inorganic features in the ancient
rock record. Stromatolites, defined as laminated biosedimentary fabrics
formed by the trapping and binding of sediments and/or
precipitation of minerals by microorganisms (Walter 1977),
are sometimes impossible to distinguish from finely laminated sediments
formed by inorganic processes"
http://geology.asu.edu/jfarmer/pubs/pdfs/taphon.pdf
Michael C. Storrie-Lombardi
NASA Astrobiology Institute
Jet Propulsion Laboratory
"The statistical analysis of stromatolites
presented here is based on the adoption of an approach
known to the Complexity research community as the
Compression and Diffusion (CD) method [1]. In this
method a set of stromatolite surface features are
converted into a sequence of symbols. The CD
method yields results that are independent of the
potential false correlations that any specific image
conversion method might create. We apply the CD
method to studying local properties, with consequently
no conflict with the non-stationary nature of the
geological process that led to the formation of
stromatolites. The compression component of the
method recognizes the existence of deterministic rules
and the diffusion component measures the speed of
transition from dynamics to thermodynamics. This
transition may be the central characteristic capable of
differentiating a biotic from an abiotic origin of the
target stromatolite, the biotic origin producing a more
significant departure from thermodynamics."
http://www.kinohi.org/pdf_files/NAI2003_Complexity.pdf
Endurance finely layered rock
http://marsrovers.jpl.nasa.gov/gallery/all/1/p/123/1P139114820EFF2815P2532R1M1.JPG
Opportunity micro images
http://marsrovers.jpl.nasa.gov/gallery/all/1/m/105/1M137503553EFF2208P2956M2M1.HTMLhttp://marsrovers.jpl.nasa.gov/gallery/all/1/m/106/1M137593860EFF2208P2956M2M1.JPG
Hydrothermal Systems:
Doorways to Early Biosphere Evolution
ABSTRACT
"Hydrothermal systems may have provided favorable
environments for the prebiotic synthesis of
organic compounds necessary for life and may also
have been a site for life's origin . They could also have
provided a refuge for thermophilic (heat-loving)
microorganisms during late, giant-impact events.
Phylogenetic information encoded in the genomes of
extant thermophiles provides important clues about
this early period of biosphere development that are
broadly consistent with geological evidence for Archean
environments . Hydrothermal environments often
exhibit high rates of mineralization, which favors
microbial fossilization."
http://geology.asu.edu/jfarmer/pubs/pdfs/gsa.pdf
The State and Future of Mars Polar Science and Exploration
"The recent identification of putative shorelines in the northern plains
suggests that the water from these events may have contributed to one or
more ice-covered lakes or seas that may have collectively covered as
much as a third of the planet . These, and other lines of evidence, suggest
that Mars is water-rich and may store the equivalent of a global
ocean of water » 0.5-1 km deep as ground ice and
groundwater within its crust (Carr 1987)."
"Whether the early climate was warm or cold, the presence of
abundant water on the surface has profound implications for the
development of life. Indeed, given the intense impact and volcanic
activity that characterized the planet at this time, the development
of long-lived hydrothermal systems was likely widespread-
duplicating many of the important conditions that are thought
to have given rise to life on Earth (Farmer 1996)."
http://geology.asu.edu/jfarmer/pubs/pdfs/marspolarsci.pdf
Morphological Biosignatures and the Search
for Life on Mars
"In microbial communities, organisms exist in a common
EPS ("slime") matrix. These materials hold great taphonomic
importance because they can control aspects of the chemical
microenvironments that promote early diagenetic mineralization,
a key factor in microbial fossilization (Farmer, 1999). EPS
is known to bind a wide variety of metals in-
cluding Pb, Sr, Zn, Cd, Co, Cu, Mn, Mg, Fe, Ag,
and Ni (Decho, 1990, and references therein)."
"The concentration of these metals above background
levels presents an interesting possibility for the
detection of organisms even after organic mate-
rials have been degraded (Farmer, 1999; Conrad
and Nealson, 2001)."
http://geology.asu.edu/jfarmer/pubs/pdfs/morpho.pdf
TAPHONOMIC MODES IN MICROBIAL FOSSILIZATION
"In conjunction with other types of chemofossil evidence (e.g., isotopes and organic
biomarker compounds), spatial distributions of trace metals that are comparable
in pattern and scale to microbial cells and biofilms may provide additional
evidence for biogenicity .
A Mossbauer investigation of iron-rich terrestrial
hydrothermal vent systems: Lessons for Mars exploration
"While a high-temperature origin for terrestrial life is still
debatable, the high biological productivity and rapid
mineralization that are typical of thermal spring environments
make them particularly favorable places for the preservation
of a microbial fossil record. For this reason, hydrothermal
deposits are regarded as important targets in the exploration
for fossil evidence of ancient Martian life"
"Among the stated capabilities of the Mossbauer instrument is the
ability to detect "nanophase and amorphous hydrothermal Fe
minerals that could preserve biological materials" (S.W. Squyres,
http://astrosun.tn.cornell.edu/athena/mossbauer.html, 1998a).
Terrestrial hydrothermal springs, including deep-sea vents,
harbor complex ecosystems that have evolved based on nutri-
ents and energy supplied by the vent effluent. Importantly,
land-based spring systems also include photosynthetic (cya-
nobacterial) species. Previously, we reported results of a
Mossbauer investigation of samples (collected by J. C. Alt)
from submarine hydrothermal vents ("black smokers") in an
area of the East Pacific Rise [Agresti et al., 19941. The iron-
rich minerals were shown by scanning electron microscopy
(SEM) to be associated with bacterial filaments [Alt, 19881."
http://geology.asu.edu/jfarmer/pubs/pdfs/mossbauer.pdf
4. Siderite as a Component of an Ancient Stromatolite
"Mossbauer spectra at two temperatures of a freshly slabbed
portion of a 2.09 Ga (Early Proterozoic) hematic chert stro-
matolite from the Gunflint Iron Formation (PPRG 2443) are
shown in Figure 26. The high-velocity ferrous peak migrates
from its position at 100 K to overlap the fifth peak of hematite
at 19 K. This behavior and the agreement of the splitting pa-
rameters with those of siderite argue that this sample contains
a small fraction of siderite. (dominant siderite peak at -1090 cm-I).
The sample investigated was freshly slabbed for the Mossbauer
transmission measurement, so the iron carbonate is interior
to the native stromatolite rock. Its occurrence in this 2.09 Ga
old rock in- dicates that long (billion-year) survival times
for siderite are possible when preserved in silica."
(Fig 26 page 15, please compare with blueberry bowl
chart for siderite signature)
http://geology.asu.edu/jfarmer/pubs/pdfs/mossbauer.pdf
A Bowl of Hematite-Rich 'Berries'
Mar 18, 2004
"This graph shows two spectra of outcrop regions near the
Mars Exploration Rover Opportunity's landing site.
The blue line shows data for a region dubbed "Berry Bowl,"
which contains a handful of the sphere-like grains dubbed
"blueberries."
Blueberry Bowl chart
http://www.jpl.nasa.gov/mer2004/rover-images/mar-18-2004/captions/image-19.html
NASA-JPL May Have Cooked Their Own Goose!
"To make a long story short (I shall over-simplify for sake of
brevity), there is increasing evidence of the function of
bacteria in rock-forming and even in some sand-forming processes
(wherein bacteria serve to nucleate the growth of small silicate
crystals). On Earth, in formation of spherical concretions,
bacterial colonies and/or other organic matter infused with
bacteria nucleate crystalline silica growth. I suspect it would
likewise be the case where Mars was wet over extended periods."
"In the wet, mushy or 'muddy' environment, the resulting micro-
concretion slowly grows (sometimes incorporating or
encapsulating adjacent grains of silt or sand, sometimes simply
by crystalline growth from colloidally suspended silica
crystallizing and pushing adjacent silt ahead of its growth,
sometimes by a combination of the two processes), increasing its
diameter spherically across time. If conditions for the
bacterial colony's growth are episodic, one can sometimes see
(upon slicing the concretion) rather distinct concentric layers
of growth that formed the concretion, but where conditions for
growth are constant, the concretion may show a crystalline
pattern with virtually no concentric layering."
http://www.virtuallystrange.net/ufo/updates/2004/mar/m03-035.shtml
..................................
There are abundant locations on Mars to search for water, but
hematite further reduces the search to areas likely to have
underground water and hot springs. And to areas showing ideal
conditions for life and fossil preservation.
They have found everything they could have expected at
Meridiani. The Big Clue is that the hematite is concentrated
in the spheres, yet little is in the soil. Another is the unprecedented
volume of spheres and laminated rocks found. Combined with
the highly uniform intra-populations sizes, a non-living
explanation for Meridiani is highly unlikely.
The question now is whether Nasa is simply being
conservative by dramatically downplaying the
capabilities and discoveries of this mission. Or
if they are willing to let the mission end as is
as a hedge to insure the coveted sample
return mission.
For Nasa to hide the discovery of extraterrestrial life
would be the 'Biggest Lie' in the history of science!
Galileo v. The Holy Inquisition would be a minor
travesty in comparison.
Nasa should not be allowed to have a Vatican-like grip
on such ...universal... discovery.
Jonathan
s
