Download Fossils of Cyanobacteria in CI1 Carbonaceous Meteorites

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Fossils of Cyanobacteria in CI1
Carbonaceous Meteorites
Hoover, R.B., Journal of Cosmology, 2011, Vol 13
Talk by Essl Noah
on May. 6, 2011
in the Seminar
"Schwerpunktseminar Astrobiologie: Habitabilitätskriterien von
(Exo-)planeten"
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Carbonaceous Chondrites - CI Group
Or Ivuna-like, Ivuna, Tanzania; 1938
Apperance:
→ „Small, black, friable, tarlike, looks like charcoal“
Components:
→ Contain water, carbon, Mg/Si ratio near solar values
→ Complete absence of chondrules and refractory inclusions
→ ~20% indigenious water, hydration on parent bodies (t<50°C)
→ crystals of olivine, pyroxene, elemental iron, presolar diamonds,
graphite, insoluble organic matter similar to kerogen
Facts:
→ Extremely rare, 9 out of ~35.000 Meteorites
→ 5 observed falls, collected directly after fall
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Falls
Name
Alais
Orgueil
Ivuna
Date
3/15/1806
5/14/1864
12/16/1938
Mass
Weak Biomarkers
Strong Biomarkers
6kg
Carbon, Water, Clay
Minerals, Organic Matter,
humus and liguite with Odor
of Bitumen, SulphHydrocarbhons, Petroleum
like Hydrocarbons, Aliphatic
and Aromatic Hydrocarbons,
PAH
Porphyrins, Pristane, NorPristane, Phytane,
Nitrogen Heterocycles and Nucleobases –
Purines and Pyrimidines, Filamentous
Microfossils, Trichomic Prokaryotes and
Cyanobacteria
Organic Matter, humus, peat
and liguite coal and clay
minerals, Amino Acids,
Normal Alkanes, „Orgenized
Elements“, Microvessicles
Long-Chain Fatty Acids, Isoprenoids,
Kerogen, Porphyrins, Pristane, NorPristane,
Phytane,Protein Amino Acids with
Enantiomeric Excess, Nitrogen Heterocycles
and Nucleobases – Purines and Pyrimidines,
Filamentous Microfossils, Trichomic
Prokaryotes and Cyanobacteria
Petroleum like
Hydrocarbons, Aliphatic and
Aromatic Hydrocarbons,
PAH
Porphyrins, Pristane, NorPristane,
Phytane,Protein Amino Acids with
Enantiomeric Excess, Nitrogen Heterocycles
and Nucleobases – Purines and Pyrimidines,
Filamentous Microfossils, Trichomic
Prokaryotes and Cyanobacteria
14kg
705g
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Alais
Orgueil
J.J. Berzelius (1836):
„I was so suspicious, because the meteorite
containes water that I was about to throw
away my sample.“
„in water it disintegrates instantaneously to
a greyish-green powder which has an odor
reminding one of fresh hay“
Ivuna
δ¹³C aprox. +60 per mil. = unlike any
terrestrial C
Excludes contamination
M. Leymerie(1864):
„the broken surface reveals a dark charcoal
colored substances so soft that it can be
easily cut with a knife. Fragments placed in
water disintergrate immediately.“
Tonk & Revelstroke
No data yet been published about organic
chemistry, only mineralogic research so far
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Methods Used:
FESEM – Field Emission Scanning Electron Microscopy
Resolution down to 1,5 nm
ESEM - Environmental Scanning Electron Microscope
For vacuum instabile samples
EDS - Energy Dispersive X-Ray Spectroscopy
Requirements:
→ uncoated, freshly fractured, interior surfaces
→ all tool, sample holders, stubs were flame sterilized
→ samples sealed at -80°C
→ all solvents, acids or liquids avoided
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Images and EDS-Spectra of Filaments in Ivuna CI1:
FESEM-Image of thin unserate filament,
flattend on the left, zylindrical in the lower part,
embedded in the meteorites matrix
→ Rich in C, Mg and S,
depleted in N
→ Enceased with
carbonacous sheath
→ EDS-Data for (1) and (3)
← Permineralized remains
of ensheathed trichomic
Prokaryote
Similar bacteria:
Spirulina subtilissima
Spirulina laxissima
Chloroflexus aurantiacus
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Images and EDS-Spectra of Filaments in Ivuna CI1:
→ length, diameter and spiral form
also found in FESEM images of
Titanospirillum Velox
→ extremophile, genus not yet validly
Published
Bacteriological Code Rules:
Procaryotic microorganisms must be isolated
and grown in pure culture in two
international culture collections and two
different countries
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Sheath 1
EDS-Spectra of Ivuna CI1
Mineral matrix
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Images and EDS-Spectra of Filaments in Orgueil CI1:
Numbers 1 – 12 are
fossil filaments
Nr.7 is the only one
with N (1%) and P
(0,8%)
EDS-Spectra from
all filaments and the
meteorite matrix
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Relative concentration
Bright in O, C, Mg, S
dark in Si, Fe, Ni
Shows the elemental
Abundance
SED-Image →
Secondary Electron
Detection
BSED-Images →
BackScattered
Electron Detection
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Images and EDS-Spectra of Filaments in Orgueil CI1:
Filament 1 & 2:
→ Sheaths with longitudinal strations
→ characteristics of multiseriate trichomic prokaryotic filaments
→ attached or physically embedded in the stones
matrix
→ bundles of parallel trichomes
→ CW: cross-wall strictions, indicate cell size
of ~4µm
→ interpretations constist with morphotypes of
undifferentiated filamentous cyanobacteria
(Oscilliatoriacea)
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Images and EDS-Spectra of Filaments in Orgueil CI1:
Filament 3 & 4 may be interpreted as Trichocoleus
Agnostidis
Filament 4:
→ hookshaped, 2µm diameter, narrowed terminus
→ several species of Trichocoleus match this criteria
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Images and EDS-Spectra of Filaments in Orgueil CI1:
9: collapsed
10: hollow, flattened, twisted and folded sheath
Spiral coil near the base
of Nr. 10 is similar to
Phormidium Stagninum
Often seen in other
Cyanobacteria →
No diagnostic
feature
www.cyanodb.cz/
db/Phormidium/
Phormidium.jpg
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Images and EDS-Spectra of Filaments in Orgueil CI1:
Filament 11:
tapered and hooked
form, cell or calyptra
in the apex
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Images and EDS-Spectra of Filaments in Orgueil CI1:
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Filaments in Orgueil with differentiated heterocysts:
→ Heterocysts used by several cyanobacteria of Nostocales and
Stignometales for Nitrogen fixation
→ unambiguous biological process that is crucial to life on Earth
→ reduces nitrogen molecules (N2) to ammonia, nitrates or
nitrogendioxide
→ higly specialized cells to encapsulate the nitrogenase enzyme
in thick-walled protective heterocysts
→ only found in Nostocales and Stigonematales
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Filaments in Orgueil with differentiated heterocysts:
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Filaments in Orgueil CI1
→ modern cyanobacteria do not actively grow in dry state
→ Orgueil meteorite is destroyed when put in water
→ no Orguiel meteorite sample was in a pool of liquid water needed for
growth of large photoautotriphic cyanobacteria
→ interpreted as indigenious remains of microfossils that were present
on the meteorite rock when it entered Earths atmosphere
→ living and dead cyanobacteria are usually damaged by the
FESEM-Beam, but Orgueil filaments were not.
→ C/N and C/S ratio similar to fossiled material and kerogen but
different from living biologic matter
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Nitrogen in fossils and living bacteria
→ Meteorites depleted in N
→ Living forms: 2% - 15%
→ even detectable in mummys
and pleistocene mammoths
→ trilobites and cyanobacteria
fossils also do not show
Nitrogen
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Amino Acids In Living Bacteria, Fossils And Meteorites
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Comets as parent bodies
Possible sources:
→ CI1 are jet black and contain extraterestrial water
→ same as many comets
→ comet temperature:
- IKS-Vega data → nucleous of Halley at 420 +/- 60K at 0,8 AU
- nucleous of 19P/Borelly at ~345K
→ cometary outflow: ISO found that Halle-Bopp released water vapor,
carbon monoxide and carbon dioxide at a rate of 2 x 10⁹ kg/sec
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Comments from other scientists
- No logic reason nor proof that life started on Earth
- there is definitely no contamination
- Wickramasinghe: cometary particles found in atmosphere with
fossils and even living bacteria
- between first planets in universe and formation of earth lies 6 Gyr
with higher SNe rate. Cyanobacteria can resist higher radiation then
present on earth.
- At 81P (Comet) were found PAH, Olivine and CAI (Ca-Al-Inclusions)
=> great mixing of material in protoplanetary disk
- not only CI and CM bur even normal chondrites were sampled
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Comments from other scientists
- we should concentrate research the origin of the structure
- the paper itself is rich in information, but it is not presented well
- existing pictures that would have prooven the facts better were not
used
- life will not have evolved from a single cell (on Earth) and Archea
and Eukaryotes must have come from space too
- possibly a remnant of prior impact on earth
- focus on thermosynthesis and temperatur gradients
- CI1 and ALH84001 have same isotopic ratio → CI1 from Mars as
well?
- Nitrogen can not be seen really good with SED, maybe use other
instruments? (contamination argument)
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Comments from other scientists
- In terms of morphology, several structures could be said to
resemble abiogenic ambient inclusion trails (AITs), commonly
mistaken for cyanobacterial microfossils, including by Hoover and his
colleagues. Such AITs are formed by the forward projection of
minerals under gaseous pressure through a solid or liquid medium.
Schwerpunktseminar Astrobiologie:
Habitabilitätskriterien von (Exo-)planeten
Questions?
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