Dr. Rocco Mancinelli Microbe expert Rocco Mancinelli is the lead researcher in one of the Carl Sagan Center’s newest on-site laboratories. Like many CSC scientists, he is interested in extremophiles, the organisms that, on Earth, live at the limits of life. A common thread of his work is the search for the definitive environmental limits within which life can arise and evolve on planets. Such data will give insight into the potential for life elsewhere in the solar system, for example, Mars.
Rocco is a renown expert on halophiles – salt-loving bacteria – which he believes might be similar to microbes elsewhere in the cosmos. He conducts field studies in a variety of different environments, ranging from the Antarctic and Alpine tundra to the hot springs of Yellowstone National Park and Chile’s Atacama desert. Rocco has even exposed microbes to the extreme cold, vacuum and zero gravity found in space, and has shown that some halophiles actually are able to survive such extreme conditions. A further research interest is the evolution of the nitrogen cycle and the role of nitrogen in microbial ecologies. Nitrogen seems a key element for two reasons: Fixed nitrogen is an important limiting nutrient in many terrestrial systems, and it appears that nitrogen would have been one of the most important limiting nutrients on Mars as well. There is much to be learned about the potential for martian life by studying the limits of life on our own world.
Projects
“Astrobiology, Planetary Protection and Life beyond the Planet of Origin” NNA04CC93A The focus of this project is on life moving beyond its planet of origin, a question of evolutionary interest and because the human exploration of space is the movement of life from Earth and the movement of possible life to Earth from other planets, especially Mars and Europa. With this project, we propose a focused research plan as a nucleus for an expanded emphasis on this area of interplanetary travel of life as the field of Astrobiology matures. Moving beyond the planet of origin requires a vehicle for transport, the ability to transport, and the ability to colonize, thrive and ultimately evolve in the new environment. The core of this study will be to identify organisms and ecosystems that are likely to withstand the rigors of space, using as a guiding principle the hypothesis that desiccation resistance and natural exposure to high levels of radiation are good predictors of survival of travel from one planet to another. Once this work — collecting candidate organisms from various environments, testing them in the lab and in a space simulator, looking at mechanisms underlying the results of survival and death — has been established, we will expand the research to include a flight component and to bring in workers from related fields to study other aspects of natural transport (natural transport mainly mean via a meteorite while intentional transport involves a sample return mission). Primary to this effort is the identification of mechanisms that permit certain organisms to withstand space radiation, space vacuum, desiccation, time in transit, and the physical rigors of leaving the parent body and landing on a new one. Each of these factors can be associated with a probability of survival— the product of the probabilities then provides an estimate of the overall likelihood of survival. This proposed research will provide new insights into the ability of life to propagate through space.
“Planetary Biology, Evolution and Intelligence” NNA04CC05A We ask three fundamental questions: (1) How does life begin and evolve; (2) Does life exist elsewhere in the universe? and (3) What is the future of life on Earth and beyond? We conduct a set of coupled research projects in the co-evolution of life and its planetary environment, beginning with fundamental ancient transitions that ultimately made complex life possible on Earth, and conclude with a project that brings together many of these investigations into an examination of the suitability of planets orbiting M stars for either single-celled or more complex life. Results will help the next generation scientific Search for Extraterrestrial Intelligence (SETI) choose the 105 to 106 target stars that it will survey for signs of technical civilizations using the new Allen Telescope Array (ATA) being built by the SETI Institute in partnership with the University of California, Berkeley. This research, sponsored by the NASA Astrobiology Institute, intends to elucidate the co-evolution of life and its planetary environment, typically investigating global-scale processes that have shaped, and been shaped by, both. Throughout, we recognize the importance of pursuing the planetary evolution aspects of this research in the context of comparative planetology: since laboratory experiments are impossible over some of the time and spatial scales relevant to early Earth, we must supplement laboratory data with the insight as we can gain by exploring extraterrestrial environments that may provide partial analogs to the early Earth environment and its processes. We will be exploring two new investigations into the oxidation of early Earths environment. While the biological aspects of this ‘oxygen transition’ have been recently emphasized, both mechanisms to be explored here (peroxy in rocks and aerosol formation in the atmosphere, building on an analogy to processes now occurring in the atmosphere of Saturns moon Titan) are non-biological. If such mechanisms were to be shown to be quantitatively significant, it would suggest that the oxygen transition on an Earth-like world could take place independently of the invention of any particular metabolic pathways (such as photosynthesis or methanogenesis) that have been proposed as driving this transition. Since Earth’s oxygen transition ultimately set the stage for the oxygen-based metabolism evidently essential for metazoa, understanding this transition is crucial to elucidating both Earth’s evolution and the evolution of complex (including intelligent) life. Our geological investigations are tightly coupled with microbiological experiments to understand the extent to which the proposed mechanism might have led to the evolutionary invention of oxidant protective strategies and even aerobic metabolism. One of the major sinks for oxygen on early Earth would have been reduced iron.At the same time iron could have provided shielding against ultraviolet (UV) light that would have been reaching Earth’s surface in the absence of the ozone shield generated by atmospheric oxygen. Nanophase ferric oxide minerals in solution could provide a sunscreen against UV while allowing the transmission of visible light, in turn making the evolution of at least some photosynthetic organisms possible. We will test this hypothesis through coupled mineralogical and microbiological work in both the lab and the field, and examine its implications not only for Earth but for Mars as well with an emphasis on implications for upcoming spacecraft observations. Co-Investigators:
Peter Backus
Amos Banin
Max Bernstein
Janice Bishop
Nathalie Cabrol
Christopher Chyba
Friedemann Freund
Edmond Grin
Bishun Khare
Cynthia Phillips
Lynn Rothschild
Seth Shostak
David Summers
Jill Tarter SETI Institute NAI NASA Astrobiology Institute (NAI)
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