Microfossils of Cyanobacteria in the Orgueil Carbonaceous Meteorite
Richard B. Hoover, BSc
Friday, 12 July 2007
Socialization : 10:15 a.m.
Presentation : 10:30 a.m.
Location: NSSTC, Room 2096
320 Sparkman Drive
Huntsville, AL 35805
During the past decade, Scanning Electron Microscopy investigations at NASA/MSFC and NSSTC have resulted in the detection of embedded coccoidal and filamentous forms in freshly fractured interior surfaces of the Orgueil CI1 carbonaceous meteorite. Many of these forms have sizes and morphologies consistent with well-known genera and species of Cyanobacteria. Similar forms have never been detected in any of the stony chondrites, achondrites, diogenites, nickel-iron meteorites or lunar samples studied. Energy Dispersive X-ray Spectroscopy (EDS) and 2D maps indicate that these filaments in Orgueil are permineralized with magnesium sulfate, encased within carbon-rich sheaths and depleted in Nitrogen. Many of the large and complex forms are polarized filaments that exhibit highly differentiated and specialized cells for nitrogen fixation (heterocysts) and reproduction (hormogonia, akinetes and baeocytes). High-resolution images will be presented to show that the Orgueil filaments are biological in origin and can be interpreted as morphotypes of all known Orders of Cyanobacteriaceae. C/S and C/N ratios will be presented to demonstrate that the forms embedded in the meteorite rock matrix cannot logically be dismissed as post-arrival biological contaminants. It is concluded that the well-preserved, fossilized filaments and dense mats found in Orgueil represent the remains of a complex aquatic and benthic cyanobacterial mat community that grew on the parent body of the meteorite prior to entry into Earth's atmosphere.
Richard B. Hoover conducts research in Microbial Extremophiles and Astromaterials at the NSSTC Astrobiology Laboratory. He has authored/edited 35 books and over 250 scientific papers. He is well known for his work on X-Ray Optics and is an internationally recognized diatomist. He Inventoried the Henri van Heurck Diatom Collection at the invitation of the Royal Society of Belgium and authored the first article on Diatoms to appear in National Geographic (June, 1979). He collaborated with the late Sir Fred Hoyle exploring the possibility that diatoms and other microorganisms might inhabit comets or the oceans of Europa. His diatom photos have appeared in many international publications published and for almost a decade his arranged diatom slides were exhibited at the American Museum of Natural History in New York. Hoover has led scientific expeditions to collect microbial extremophiles in California, Santorini, Hawaii Alaska, Patagonia, North Siberia and Antarctica that resulted in the discovery and valid publication of a new genus Anaerovirgula and several new species of bacteria and archaea. Astronauts James Lovell and Owen Garriott participated in the Antarctica 2000 Expedition that resulted in the discovery of the new species Trichococcus patagoniensis that grows at -5 degrees C. The new species Tindallia californiensis, Desulfonatronum thiodismutans and Spirochaeta americana (a hydrogen producer) were discovered in samples from Mono Lake and Carnobacterium pleistocenium is a living Pleistocene bacterium recovered from 32,000 year old ice sample from the Fox Tunnel of Alaska. Thermococcus thioreducens is a new species of archaeon from the Rainbow Hydrothermal Vent that will be published in July 2007. He has extensively studied living cyanobacteria, cryopreserved cyanobacteria in the Deep Vostok Ice Cores and cyanobacterial microfossils in Proterozoic Phosphorites from Mongolia and Archaean rocks from Siberia. Hoover is a Fellow of SPIE and was 2001 SPIE President. He served on several Boards of Directors: SPIE; American Association of Engineering Societies; and Council of Scientific Society Presidents as well as Editorial Boards of several Journals: Journal of X-Ray Science and Technology, Optical Engineering, Advances in Optical Technology; and Astrobiology and his book Perspectives in Astrobiology was published in 2005. Richard Hoover was elected a Fellow of the Explorers Club (2001) in recognition of his exploration in search for novel life forms in some of the most hostile environments on Earth, and his detection of evidence of microfossils in meteorites, led to his selection as an Honorary Life Member (2004) of the Planetary Studies Foundation.
Richard Hoover has led scientific expeditions to collect extremophiles in the permafrost and glaciers of North Siberia, Alaska, Patagonia and Antarctica; haloalkaline lakes, geysers and fumaroles of California, Santorini, and Hawaii. He was Science Team Leader to the Patriot Hills, Thiel Mountains, and South Pole of Antarctica. These expeditions resulted in the discovery and valid publication of several genera and species of bacteria and archaea previously unknown to science. Astronauts James L. Lovell and Owen K. Garriott participated in Antarctica 2000 Expedition, which resulted in the discovery of Trichococcus patagoniensis that can grow at -5 degrees C. Novel species of bacteria: Tindallia californiensis, Desulfonatronum thiodismutans and Spirochaeta americana (which produces hydrogen as its main waste product) were isolated from samples he collected in Mono Lake, CA. Carnobacterium pleistocenium is a living Pleistocene microorganism that he recovered from 32,000 year old ice of the Fox Permafrost Tunnel in Alaska. The new genus Anaerovirgula multivorans is unusual in that it can grow on both D- and L- sugars. Thermococcus thioreducens is a novel archaeon collected by Owen Garriott from the Rainbow Hydrothermal. He is Fellow of SPIE and was 2001 SPIE President of SPIE. He has served on the Boards of Directors of SPIE; the American Association of Engineering Societies; and the Council of Scientific Society Presidents and the Editorial Board of: Journal of X-Ray Science and Technology, Optical Engineering and Astrobiology. His book Perspectives in Astrobiology was published in 2005. In recognition of his exploration in some of the most hostile environments on Earth in search of novel life forms, Hoover was elected a Fellow of the Explorers Club in 2001. His research on new species of microbial extremophiles and the detection of evidence of microfossils in meteorites, led to his selection in 2004 as an Honorary Life Member of the Planetary Studies Foundation.
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