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Bower Receives NASA Postdoctoral Fellowship at the Carnegie Institution of Science for Earliest Life Studies

Dina Bower (pictured right), who received her Ph.D. in ocean, earth, and atmospheric sciences from Old Dominion University earlier this year, has received a NASA fellowship to do postdoctoral work at Carnegie Institution of Science in Washington, D.C., where she will study new ways to detect evidence of the microbes that lived on Earth billions of years ago, and possibly on other planets as well.

"I am very proud of Dina," said Nora Noffke (pictured left), ODU associate professor of ocean, earth and atmospheric sciences, who was Bower's doctoral adviser. "These fellowships are highly competitive and based on a national and an international search."

The young researcher will work under the direction of Andrew Steele, a staff member at the Carnegie Institution's Geophysical Laboratory who is a leader in life-on-Mars studies for NASA. "This study will provide much needed information that can be applied to understanding the origins of life on Earth and other planets," Bower said.

With Noffke at ODU, Bower studied geological structures found in ancient rocks that can be traced to cyanobacterial mats-blanket-like weaves of microbial colonies. These mats can be seen today on the surface of tidal flats.

As a graduate student in the 1990s in Germany, Noffke observed that the mats leave distinctive markings on the sediments under them, and she wondered 1) if similar mats existed early in the existence of life on Earth, and 2) if so, whether the same patterns created in sediments by today's mats would be preserved in the geological record. Noffke and Bower eventually would find these patterns and structures in 3-billion-year-old rocks in southern Africa, establishing some of the sturdiest evidence yet of the first microbial life that colonized seaside areas of Earth.

For her doctoral thesis, Bower focused on how the research findings from the cyanobacterial mat studies could be applied to NASA's search for life on Mars.

The postdoctoral work will take a different tact toward finding signs of early life in the geological record. Bower will investigate ways to use minerals as biosignatures in ancient rocks. According to her research topic, this will involve "experimental investigations on the effects of diagenesis and low-grade metamorphism on the preservation of organic matter and formation of iron and titanium oxides in microfossils."

Diagenesis and metamorphism comprise the chemical, physical and thermal processes that turn sediments into rock. In her laboratory experiments, Bower will recreate the processes and compare the development of mineral precipitates produced by microbes to those formed inorganically. Her findings will help geologists studying ancient rocks to tell the difference between trace minerals and mineral formations that originated with life forms and those that are inorganic. The product of her work could be put to use on Mars as well as Earth.

The laboratory experiments will include analysis by sophisticated instruments. Micro Raman spectroscopy will be used to identify minerals and to create spectral maps showing the spatial relationships between microstructures and mineral phases in the study samples. Mossbauer spectroscopy will be used to track thermal effects on the samples. And a focused-ion-beam transmission electron microscope will provide imaging of morphological characteristics of the original microbial cells and subsequently formed microfossils.

"Dina was a very independent student, and came up always with her own ideas about how to approach different questions on the taphonomy (path of preservation) of bacteria," Noffke said. "She has developed by herself new analytical techniques to study fossil bacteria in rocks. For the first time, geobiologists now use her method to investigate fossil bacteria with confocal and micro Raman microscopes. Dina's work is very well received by the scientific community."

Noffke said the search for bacteria in Archean rocks that are 3 billion years old requires "patience, long hours in the laboratory, a good eye and fundamental knowledge of where to look in several miles of thick rock succession" in order to find target samples. "Dina's analytical methods not only assist us in detecting bacterial fossils, but also in learning about minerals that compose the fossils. And from that we can reach conclusions about paleoenvironmental conditions such as seawater chemistry and atmospheric composition."

This article was posted on: October 13, 2008

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