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Astrobiology (general): July 2010


A NASA Astrobiology Institute-funded study led by Chris Dupont of the J. Craig Venter Institute indicates that environmental availability of trace elements over Earth's history influenced the selection of elements used by life as biological evolution progressed. Their results show that environmental concentrations of trace metals influenced which types of metal-binding proteins evolved, and the relative timing of their evolution.

The study implies that the geochemistry of the Archean ocean (>2.5 billion years ago) influenced both the evolution of metal-binding protein architectures and the selection of elements by the ancestors of modern Archaea and Bacteria (simple single cell organisms). Specifically, low Zn, Mo, and Cu concentrations in the Archean ocean likely prevented the widespread emergence and diversification of Eukaryotic life (including plants, animals, and fungi) until the oceans became oxic, relatively late in Earth's history. The study also revealed that although modern Archaea and Bacteria still predominantly use ancient metal-binding protein structures, most Eukaryotes use both early- and late- evolving structures. The paper appears in the May 24 Early Edition of PNAS.

Source: NAI Newsletter

Please join us in congratulating former NAI Director Bruce Runnegar of UCLA for receiving the 2009 Lapworth Medal from the Paleontological Association!

Bruce Runnegar has been one of the most innovative researchers of his generation, and a testament to the visionary nature of his research and its endurance. Of course, taxonomic works in palaeontology have a long 'half-life', but review papers tend to burn brightly and quickly. Runnegar has published his fair share of taxonomic studies, elucidating the early evolutionary history of molluscs. However, he also has an enviable back-catalogue of reviews and opinion pieces that were not merely of the moment, but remain as relevant and inspirational today as when they were published, many of them decades ago, and they continue to accrue citations as a result.

Runnegar's 1982 Geol Soc Australia article codified the conundrum of the Cambrian Explosion - whether it should it be interpreted as an explosion of animal diversity, or merely of fossils. He made the first serious attempts to tackle this problem, by employing the molecular clock, long before it became fashionable among molecular biologists (for whom it is now an industry), in trying to obtain an independent timescale for animal evolution. He is believed to be the first person to codify the concept of disparity used by Gould as the centrepiece of his thesis in Wonderful Life. Furthermore, Runnegar had reconciled the 'weird wonders' of Wonderful Life as stem members of extant animal phyla soon after its publication, but it took almost a decade for the debate to catch up.

Runnegar's vision was ultimately distilled in the written account of his 1985 address to the Palaeontological Association in which he argued that palaeontology is a discipline concerned with fundamental questions, that the most appropriate dataset to answer these questions is not always to be found in lumps of rock, and that all relevant data and methods should be brought to bear in attempts to resolve these questions. This perspective is held generally among palaeontologists, and he has a flourishing following of disciples, but no one has fulfilled the promise of this integrative vision as has Runnegar, evidenced, not least, by his appointments as Director of the UCLA Astrobiology Center, and of the NASA Astrobiology Institute.

For more information: http://www.palass.org/modules.php?name=palaeo&sec=awards&page=120

Source: NAI Newsletter

The NAI is pleased to announce the 2010 Selections for the Lewis and Clark Fund for Exploration and Field Research in Astrobiology.

1. Knicole Colon, U Florida, travel to Spain for her project, "From Hot-Jupiters to Super Earths: Characterizing Transiting Extrasolar Planets with GTC/OSIRIS".

2. Andrew Czaja, U Wisconsin, travel to Australia for a "Field Trip to Explore Archean and Proterozoic Geology of Western Australia".

3. Jason Huberty, U Wisconsin, travel to Australia, for the "Fifth International Archean Synposium Field Trip to the Pilbara Craton, including the Fortescue and Hamersley Basins".

4. Michele Knowlton, Arizona State U, travel to Yellowstone National Park to examine nitrogen fixation occurring within microbial mats.

5. Nancy McKeown, U California, Santa Cruz, travel to Arizona, for a "Spectral Study Of the Painted Desert, AZ, to "Characterize Clay Alterations Environments and Provide Implications for Astrobiology at Mawrth Valis, Mars, a Likely Mars Science Laboratory Landing Site".

6. Elizabeth Percak-Dennet, U Wisconsin, travel to Australia, "Linking Laboratory and Field Studies of the Mineralogical and Iron Isotope Composition of Banded Iron Formations in Western Australia".

7. Matthew Urschel, Montana State U, travel to Alberta, Canada to examine "Iron Reduction in the Subglacial Sediments of Robertson Glacier, Canada".

For more information: http://astrobiology.nasa.gov/nai/funding/lewis-and-clark

Source: NAI Newsletter

Please join us in congratulating NAI PI David Des Marais for his recent election as Fellow of the American Academy of Microbiology!

Dave's early interest in exploring caves in southern Indiana on weekends while an undergraduate student at Purdue University led him to post-graduate studies in Geology at Indiana University, where he also earned a Ph.D. in Geochemistry and became fascinated with microbiology. Today, he is a PI in the NASA Astrobiology Institute (NAI) at NASA Ames, and also serves on NASA's Mars Exploration Rover mission as a long-term planning lead for the Spirit rover.

This month, Des Marais was inducted as a Fellow of the American Academy of Microbiology for his 35 years of research. Fellows are selected through a rigorous peer review process based on scientific achievements and original contributions that have advanced the field of microbiology.

"I gained most of my microbiology experience while doing postdoctoral research at UCLA and through interdisciplinary collaborations throughout my career," said Des Marais.

For the past 26 years he has coordinated an interdisciplinary team to study cyanobacterial mat (biofilm) communities in Baja California to get a glimpse of what ancient biological communities resembled. He also has conducted field research on ancient fossilized microbial communities in Australia, Canada, South Africa and the U.S. His lifelong research interests include the biogeochemical carbon cycle, the early evolution of Earth and its biosphere and searching for fossil evidence of life on Mars.

His explorations of the Red Planet also include contributions to the Mars Exploration Rover, Mars Reconnaissance Orbiter and the Mars Science Laboratory missions. This summer he will begin his tenure as Chair of the Mars Exploration Program Analysis Group (MEPAG), a public forum that obtains guidance from the science community for NASA's Mars Program regarding future exploration.

Des Marais has authored or co-authored more than 160 peer-reviewed articles and book chapters and serves on the editorial boards for the journals Astrobiology and Geobiology.

For more information: http://academy.asm.org/index.php?option=com_content&view=article&id=56&Itemid=75

Source: NAI Newsletter