Indigenous microfossils in carbonaceous meteorites

Hoover, Richard B.; Jerman, G. A.; Rozanov, A. Yu.; Sipiera, P. P.

doi:10.1117/12.566491

Cited by 17 publications

(15 citation statements)

References 29 publications

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“…7 During the past 14 years, many large, complex filaments, consortia and mat assemblages have been found with undeniable biological characteristics that were interpreted as indigenous microfossils in carbonaceous meteorites during both independent and collaborative SEM, ESEM and FESEM investigations carried out in the United States and Russia. [8][9][10][11][12][13][14][15][16][17][18][19][20][21][22] Many of the filamentous and coccoidal microstructures found during this research were consistent with forms found half a century ago by earlier researchers (e.g., Nagy, Claus, Fitch, Palik, Timofeyev and van Landingham) and interpreted as indigenous microfossils of blue-green algae (cyanophytes), bacteria, and acritarchs or dismissed as recent bacterial contaminants or pollen grains. [23][24][25][26][27][28][29][30][31][32] The filaments detected at NASA/MSFC were imaged with secondary and backscattered electron detectors and analyzed by EDS to obtain spot data and 2D x-ray maps at voltages ranging from 5 keV to 15 keV.…”

Section: Introductionsupporting

confidence: 75%

“…Coccoidal forms and filaments had been found in carbonaceous meteorites by earlier workers and interpreted as indigenous remains of algae, acritarchs, cyanobacteria or other filamentous trichomic prokaryotes. [5][6][7][8][9][10][11][12] Entirely independent SEM studies of the Murchison (CM2) and Efremovka (CO2) carbonaceous meteorites were carried out in Moscow by Rozanov and his co-workers at the Paleontological Institute (PIN) and at the Institute of Microbiology (INMI) of the Russian Academy of Sciences. They had detected a large suite filaments in entirely different samples from the meteorite collection of the Vernadsky Institute with similar sizes and morphologies to those found at NASA/MSFC.…”

Section: Introductionmentioning

confidence: 99%

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Filaments in carbonaceous meteorites: mineral crystals, modern bio-contaminants or indigenous microfossils of trichomic prokaryotes?

Hoover

Rozanov

2011

SPIE Proceedings

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Environmental (ESEM) and Field Emission Scanning Electron Microscopy (FESEM) investigations have resulted in the detection of a large number of complex filaments in a variety of carbonaceous meteorites. Many of the filaments were observed to be clearly embedded the rock matrix of freshly fractured interior surfaces of the meteorites. The high resolution images obtained combined with tilt and rotation of the stage provide 3-dimensional morphological and morphometric data for the filaments. Calibrated Energy Dispersive X-ray Spectroscopy (EDS) and 2-D elemental X-ray maps have provided information on the chemical compositions of the filaments and the minerals of the associated meteorite rock matrix. These observations are used to evaluate diverse hypotheses regarding the possible abiotic or biogenic nature of the filaments found embedded in these meteorites.

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Section: Introductionsupporting

confidence: 75%

Section: Introductionmentioning

confidence: 99%

Filaments in carbonaceous meteorites: mineral crystals, modern bio-contaminants or indigenous microfossils of trichomic prokaryotes?

Hoover

Rozanov

2011

SPIE Proceedings

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“…3c & d) surrounded with high carbon (kerogen) sheaths. 34 It is important to note that the ability of a small number of microorganisms to multiply by binary fission into phenomenally large numbers in short time periods when conditions are suitable have been well known to microbiologists. …”

Section: Comets Meteor Streams and Meteoritesmentioning

confidence: 99%

Astrobiology of comets

Hoover

Pikuta

Wickramasinghe

et al. 2004

Instruments, Methods, and Missions for Astrobiology VIII

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We review the current state of knowledge concerning microbial extremophiles and comets and the potential significance of comets to Astrobiology. We model the thermal history of a cometary body, regarded as an assemblage of boulders, dust, ices and organics, as it approaches a perihelion distance of ~ 1AU. The transfer of incident energy from sunlight into the interior leads to the melting of near surface ices, some under stable porous crust, providing possible habitats for a wide range of microorganisms. We provide data concerning new evidence for indigenous microfossils in CI meteorites, which may be the remains of extinct cometary cores. We discuss the dominant microbial communities of polar sea-ice, Antarctic ice sheet, and cryoconite environments as possible analogs for microbial ecosystems that may grow in sub-crustal pools or in ice/water films in comets.

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“…Investigations have been carried out in the United States at the NASA/Marshall Space Flight Center (Hoover, 1997Hoover and Rozanov, 2003;Hoover et al, 1998Hoover et al, , 2004a and in Russia at the Paleontological Institute, Russian Academy of Sciences (Zhmur et al, 1997;Gerasimenko et al, 1999;Rozanov and Hoover, 2002). The work at NASA has involved the study of the freshly fractured interior surfaces of most major groups of …”

Section: Recent Evidence For Microfossils In Carbonaceous Meteoritesmentioning

confidence: 99%

“…Studies of cryoconite microbial ecosystems have provided new data concerning the microbial compositions of communities that thrive in water films surrounding rocks 15 embedded in the ice of glaciers and the polar ice caps. Hoover et al (1986Hoover et al ( , 2001Hoover et al ( , 2004a have suggested that pockets and pools of meltwater trapped in interior cavities just beneath the comet crust could sustain pressures sufficiently high to allow the existence of liquid water for periods of time sufficient to allow growth of microorganisms and the formation of microbial mats. …”

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confidence: 99%

Comets, Carbonaceous Meteorites, and the Origin of the Biosphere

Hoover¹

Biosphere Origin and Evolution

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The Biosphere is considered to represent the Earth's crust, atmosphere, oceans, and ice caps and the living organisms that survive within this habitat. This paper considers the significance of comets and carbonaceous meteorites to the origin and evolution of the Biosphere and presents new Field Emission Scanning Electron Microscope (FE-5 SEM) images of indigenous microfossils in the Orgueil and Murchison meteorites. The discovery of microbial extremophiles in deep crustal rocks, hydrothermal vents and ancient ice has established that the biosphere is far more extensive than previously recognized. Chemical and molecular biomarkers and microfossils in Archaean rocks indicate that life appeared very early on the primitive Earth and the origin of the bio- 10sphere is closely linked with the emergence of life. The role of comets, carbonaceous meteorites, interstellar dust and asteroids in the delivery of water, organics and prebiotic chemicals to Earth during the Hadean (4.5-3.8 Ga) period of heavy bombardment has become more widely recognized. Spacecraft observations of the chemical compositions and characteristics of the nuclei of several comets (Halley, Borrelly, Wild 2, and 15Tempel 1) have established that comets contain complex organic chemicals; that water is the predominant volatile; and that high temperatures (∼400 K) can be reached on the black (albedo∼0.03) nuclei when near perihelion. The microscopic dust particles in the Tempel 1 ejecta are similar in size to the particulates of the Orgueil meteorite and evidence is mounting that comets may represent the parent bodies of the CI me- EGU orites have resulted in the detection of well-preserved remains of large, complex and highly differentiated filamentous microfossils, mats, and consortia embedded in freshly fractured interior surfaces of the rock matrix. Energy Dispersive X-ray Spectroscopy (EDS) data indicate that these remains are mineralized and consequently they are interpreted to represent indigenous microfossils rather than recent microbial contami-5 nants. The detection of indigenous microfossils in carbonaceous meteorites suggests that the paradigm of the endogenous origin of life on Earth may also require reconsideration.

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Indigenous microfossils in carbonaceous meteorites

Cited by 17 publications

References 29 publications

Filaments in carbonaceous meteorites: mineral crystals, modern bio-contaminants or indigenous microfossils of trichomic prokaryotes?

Filaments in carbonaceous meteorites: mineral crystals, modern bio-contaminants or indigenous microfossils of trichomic prokaryotes?

Astrobiology of comets

Comets, Carbonaceous Meteorites, and the Origin of the Biosphere

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