Astrobiology: The Sky's No Limit

How rare is it for a recent postdoc to work in an emerging scientific discipline? Or do research on fundamental problems like the origin of life on Earth, the existence of life in other parts of the universe, or the future of life in space? How rare is it to participate on a research team spanning many scientific disciplines, including astronomy, biology, chemistry, geology, genetics, oceanography, paleontology, and planetary science?

Just such an opportunity now exists for six postdoctoral awardees who will be accepted into the NASA Astrobiology Institute's Postdoctoral Fellowships Program for 2002. Applications are due in mid-January.

What Is Astrobiology?

One of the world's oldest ideas--that life developed and exists in more places than just Earth--is now one of the world's newest research programs. Astrobiology, a field that didn't exist before 1995, is a multidisciplinary approach to studying life on Earth--and in space.

Several recent advances have made astrobiology viable. Biologists have discovered extremophiles--microorganisms living in extremes of heat, cold, radiation, and pressure--and ancient organisms that derive their energy from chemosynthesis instead of photosynthesis. These organisms show that life's potentially habitable zone includes terrestrial planets like Mars and moons like Europa and Titan. Meanwhile, astronomers have observed the formation of organic chemicals in stellar nebulae and discovered over 70 Jupiter-sized extrasolar planets circling nearby stars. Chemists have analyzed potential biogenic compounds in martian meteorites such as ALH-840001. Planetary scientists and geologists have gathered evidence pointing to the existence of life-supporting liquid water on Mars's surface in the past, and presently under Europa's frozen surface. Geneticists and information scientists have built and are building models for the transition of organic molecules to self-replicating living organisms, based on theories of Earth's early development provided by astronomers, geologists, and oceanographers and on the evidence of fossilized microorganisms discovered by paleontologists.

NASA's Astrobiology Institute

These advances led to the creation of the NAI's astrobiological goals.

NASA Astrobiology Institute Lead Team Institutions

NASA Centers

Ames Research Center

Jet Propulsion Laboratory (two lead teams)

Johnson Space Center


Arizona State University

Harvard University

Michigan State University

Pennsylvania State University

University of California, Los Angeles

University of Colorado, Boulder

University of Rhode Island

University of Washington

Research Centers

Carnegie Institution of Washington

Marine Biological Laboratory

Scripps Research Institute

NAI coordinates the long-distance collaborations of six focus groups designated to explore such research topics as "Mission to Early Earth," "Mixed Microbial Ecogenomics," "EvoGenomics," and "Astromaterials," as well as the exploration of Mars and Europa.

NRC/NASA's Astrobiology Institute Postdoctoral Fellowships and Associateships

Each year NAI offers six postdoctoral awardees the opportunity to join ongoing research as visiting fellows/associates. Each NRC/NAI fellow is based at one of the NAI member research or academic institutions, but can interact with researchers across NAI. The National Research Council (NRC) administers the postdoctoral appointments for NASA.

NRC/NAI fellowships are for 1 year and are renewable. Applicants must indicate which of the participating NAI institutions they want as their primary research base and choose one of several NAI scientists who have agreed to serve as advisers to NIA postdoctoral fellows. Candidates must also propose a significant, innovative piece of research, which they have discussed in advance with their prospective colleague and host institution. Application materials are available online and the deadline for the 2002 fellowships applications is 15 January 2002.

Edward Goolish, science projects manager for NAI at its central offices at NASA's Ames Research Center in Moffett Field, California, calls the research fellows "ambassadors who communicate between teams of scientists and the public." According to Goolish, fellows like Virginia Edgecomb, who studies extremophiles living in and near geothermal vents, could do this kind of research as a narrow specialty. "But as an astrobiologist, her presence with a multidisciplinary team of scientists adds a much broader context to what she's studying, interacting with other scientists studying the phylogeny of vent-dwelling organisms. When viewed from the perspective of astrobiology, her work has greater significance for life on Earth and perhaps also for extraterrestrial environments such as Europa."

Goolish firmly believes in the collaborative, interdisciplinary approach NAI is taking. Before NAI, he says, "Scientists in individual disciplines weren't speaking to each other or putting the pieces together. That needs to happen for astrobiology to progress, and to find the connections that would not have been revealed otherwise."

But Goolish counsels prospective applicants to be prepared. "You need rigorous training in one of the classical fields. Your research must be first-rate, but there should also be some recognition that important problems and interests exist outside your discipline."

Current NRC/NAI Fellows

The first two groups of six NRC/NAI postdoctoral fellows are now doing research with the NAI. Virginia Edgecomb works with the NAI lead team at the Marine Biological Laboratory, in Woods Hole, Massachusetts. She describes her project as studying hyperthermophilic archaea, the living occupants of deep-sea hydrothermal vents that survive in extreme heat, pressure, and chemical toxicity. She is testing the limits of survivability of some archaea under different conditions of acidity, pressure, temperature, and metal concentration in order to determine the range of environmental conditions in which these organisms could be found. Her results may have implications not only for understanding the ecology and evolution of prokaryotic life here on Earth, but for life existing in similar deep-subsurface biospheres--perhaps a biosphere existing under Europa's frozen surface.

Another fellow, Eric Gaucher, works with a team at the University of Florida affiliated with the Scripps Research Institute. Gaucher works on developing computational methods of detecting the creation of original proteins from changes in gene sequences and hopes to use a combination of computational, evolutionary, and structural methods to locate sites on genomes where mutations or copy errors may create new proteins. He is also interested in using computational analyses to infer the sequences of ancient proteins, reconstructing them in order to understand the chemistry and biology that existed when eubacterial life emerged. Gaucher works within the Evogenics Focus Group, which attempts to interpret genomic information from a historical or evolutionary perspective in order to study the origin and adaptation of life on Earth, and perhaps other planets.

NAI Fellow Yanan Shen, whose research base is with an NAI team at Harvard, is interested in the relationship between life and the various environments that have existed as the Earth was formed and developed. His research attempts to elucidate how ocean chemistry in the Mesoprotozoic Age (1.6 billion to 1 billion years ago) interacted with biological selection. Examining the distribution patterns of microfossils, Shen's Harvard colleagues have discovered that the marine eukaryotic algae of 1.5 billion years ago occupied only the ocean shallows and not the deeper basins, indicating a smaller oxygen concentration in the atmosphere than exists today. Shen's own work demonstrates that the deeps of the Proterozoic ocean were full of sulfidic gases, not dissolved oxygen, and indicates that a complex natural environment, complete with a food chain and natural selection, was in place on Earth at an early date.

All three current NRC/NAI fellows confirm the value of the multidiscipline work teams. "What makes this postdoc unique," says Edgecome, "is the interaction with scientists outside my field who are also studying astrobiology and are interested in looking for life in extreme environments--but who approach these questions from a different perspective. This presents unique challenges, such as communicating the relevance of your work to scientists outside your own field, as well as recognizing unanticipated opportunities for cross-disciplinary collaboration."

Gaucher appreciates the value placed on the connections being forged. "One could argue that in many ways the typical research laboratory is today paralyzed by a reductionism paradigm. Typically research is very narrow and focused on only a subset of issues related to a particular problem. However NASA, as both a funding and research institution, has realized the importance of research intended to provide a description of the "big picture" for chemical and biological systems. The institute encourages us to understand our own specific research from a historical perspective encompassing multiple disciplines."

Shen feels fortunate to be working with a diverse team of specialists that includes a molecular biologist, an organic geochemist, a paleobiologist, and geologists. "I can learn from the molecular biologist in our group how phylogenic data shed new light on our understanding of the evolution of cyanobacteria in Earth history. I can discuss with our paleobiologist how the new fossil record improves our knowledge of eukaryotic evolution. It's a unique opportunity."

Career Opportunities

What are the career opportunities for an NRC/NAI fellow? None of the postdocs has yet left the 2-year-old program, but, says Gaucher: "One aspect of being associated with NAI is that I'm able to interact with many of the world's brightest researchers. The institute is, in many ways, a think tank, which enables me to swim around, ask questions, and thus learn from cutting-edge scientists. I'm fortunate in that the leading researchers in my field are with the institute, so not only do I get to know them, but they get to know me. That can only be beneficial when I seek future employment."

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