Dr. David Des Marais is a senior scientist at NASA Ames Research Center. He has been the Principal Investigator of the Ames Research Center team of the NASA Astrobiology Institute since 1998. He coordinated a long-term study of benthic cyanobacterial ecosystems in marine hypersaline environments in Baja California Sur, Mexico. David has investigated the geochemistry of lunar samples, meteorites and both volcanic and ancient sedimentary rocks from Earth. He is a member of the science teams of NASA’s 2003 Mars Exploration Rover mission, the 2005 Mars Reconnaissance Orbiter mission, and the 2009 Mars Science Laboratory mission. He has published more than 160 technical articles and chapters on these research topics. He has contributed to program planning at NASA and is currently Chair of the Mars Exploration Program Analysis Group. He is a Fellow of the Geochemical Society, the European Association of Geochemistry, the International Society for the Study of the Origins of Life, the California Academy of Sciences, the American Geophysical Union, and the American Academy of Microbiology.