NASA Astrobiology Institute (NAI)

1. Laboratory Microbial Simulations: Astrobiological Signatures

   Project Investigators: Jean Brenchley, Christopher House

   Other Project Members

   Beth Bauman (Masters Student)

   Emily Beal (Doctoral Student)

   Jennifer Biddle (Collaborator)

   Vyllinniskii Cameron (Doctoral Student)

   Libby Hausrath (Doctoral Student)

   Amanda Klingensmith (Doctoral Student)

   Jim Moran (Collaborator)

   Aubrey Zerkle (Collaborator)

   Zhidan Zhang (Research Staff)

   Summary

   We aim to use laboratory and field environments to investigate microorganisms and their biogeochemical signatures. We have investigated methanotrophic seeps and deeply-buried marine environments, as well as used laboratory pure-cultures to further our understanding of diverse metabolisms.

   Astrobiology Roadmap Objectives:

   • Objective 2.1: Mars exploration
   • Objective 4.1: Earth's early biosphere
   • Objective 5.1: Environment-dependent, molecular evolution in microorganisms
   • Objective 5.2: Co-evolution of microbial communities
   • Objective 5.3: Biochemical adaptation to extreme environments
   • Objective 7.1: Biosignatures to be sought in Solar System materials

   Project Progress

   This past year we had very important papers published on a number of different topics. The following are examples. We showed that cyanobacteria have a distinct nitrogen isotopic signature when exposed to high Fe concentrations, a condition that might occur during ocean anoxic events (published in JGR). We showed that Methanosarcina can grow by producing methyl-sulfides (published in AEM). We presented a new model for how the anaerobic oxidation of methane might operate (published in Environmental Microbiology). We published a paper on the metagenomic signatures of microbial life in the marine subsurface (published in PNAS).

   Cross-Team Collaborations

   The project involved Andreas Teske (UNC; part of MBL team), Sorel T. Fitz-Gibbon (UCLA), Kevin McKeegan (UCLA), and Victoria Orphan (Caltech; part of Ames team). These researchers have been an important part of our work from some time, and the collaborations have resulted in important sights and data that lead to publications.

Publications

Beal, E. & House, C.  (2008).  Microbial Reduction of Manganese and Iron as a Sink for Methane and a Plausible Metabolism on Mars.  Astrobiology:422.