2006 Annual Science Report

NASA Ames Research Center Reporting  |  JUL 2005 – JUN 2006

Biosignatures in Chemosynthetic and Photosynthetic Systems

Project Summary

During the past year, our team has made strong contributions in research, mission involvement, synergistic community activities, and education & public outreach.

4 Institutions
3 Teams
0 Publications
0 Field Sites
Field Sites

Project Progress

During the past year, our team has made strong contributions in research, mission involvement, synergistic community activities, and education & public outreach.



We have published and presented results of our studies on both chemosynthetic and photosynthetic systems:

  • Our work with chemosynthetic systems has led to publications that establish energetic boundary conditions on subsurface life, and that assess the life-supporting potential in actively serpentinizing ultramafics — a potential analog for past and modern activity on Mars. By quantitatively addressing the potential of both biological and abiological source terms, this work will aid in interpreting the potential origin of methane in the Martian atmosphere. Our focus on serpentinizing ecosystems and their analogy to Mars is being extended in several research venues: (i) we have undertaken biomarker studies of a seafloor serpentinizing system, Lost City, which will aid in identifying the biological processes that can be supported by such activity; (ii) we have initiated consortium studies on evidence of alteration in a recently discovered Martian meteorite with extensive ultramafic mineralogy, which will yield information about the nature of ultramafic alteration on the Martian surface; (iii) we are participating in Mars test bed activities that will deploy MSL instrumentation on ultramafic terranes (among others) in an arctic Mars analog. Our team’s participation will focus on characterizing primary and alteration mineralogy of the ultramafic terranes using CheMin (one of the two principal instruments on MSL, with team member David Blake as the instrument PI).
  • Our work with photosynthetic microbial mats has led to development of an energy-balance model that offers a novel approach for quantifying and predicting chemical partitioning and volatile efflux. We have quantified the significance of night-time fermentation of photosynthate in microbial mats to volatile efflux (including potential biomarkers) and to engagement of anaerobic populations, with particular emphasis on the importance for chemical cycling on the Archaean Earth. We have completed early phase studies that document the degradation of potential biomarker compounds in hypersaline evaporitic systems. The work is directly relevant to interpretation not only of evaporite deposits in earth’s rock record, but also to understanding the origin of any organics that might be found (e.g., by SAM on MSL) in the apparently extensive evaporite basins of Mars. We have initiated a detailed study to characterize the sulfur cycle in microbial mats over a range of sulfate concentrations representing modern to Archaean levels. The results will have significance for understanding the contribution of mat systems to the redox budget on early earth, for interpreting the sulfur isotope record in early rocks (with implications for understanding the rise of the sulfur cycle and the pace of global oxidation), and for understanding the contribution of volatile organosulfur compounds (as potential biomarkers) to the atmosphere.
  • Working within the context of our photosynthetic systems activity, our collaborators on the Colorado lead team have deeply surveyed the microbial diversity of the microbial mats that form our principal study system. The results have significantly expanded the known diversity of bacteria at the division level, and yielded a new kingdom-level candidate in the Eukarya. These findings are addressed within the context of our geochemical characterization of the system.

Team members are directly involved in astrobiology-related missions, and in mission-supporting activities:

  • Team members are represented as instrument PIs and interdisciplinary scientists on several active and planned missions, including MER, MRO, and MSL. The environments to be studied with these missions (including potentially serpentinizing ultramafics and evaporitic systems) have direct analogs in the focal environments (ophiolites and hypersaline ecosystems, respectively) of our ongoing research.
  • We continue our participation in a Mars test-bed activity that will deploy the principal instrument package of MSL in an arctic Mars analog environment on Spitzbergen (Norwegian Arctic). Aspects of this analog activity will include mineralogical studies of ultramafic terranes, providing a direct link to our ophiolite work.

We contributed materially to astrobiology community-building activities:

  • Team members participated in the Microbial Systems Exploration Initiative activity as steering committee members, invited speakers, and principal contributors to the white papers that emerged from the workshop. We were further involved in presenting the results to Earth and Space Sciences program managers at NASA HQ, in an effort to emphasize the connections of astrobiology research to Earth Sciences objectives.
  • We organized a special session (“Follow the Energy”) at the Astrobiology Science Conference that led to a “Science News” highlight, and will now serve as the basis for a special issue of Astrobiology. One of us participated in the conference symposium, “Astrobiology: Vision for Exploration.” Additionally, team members served on the conference program organizing committee.
  • Our team participated directly in the preparation of an HQ-mandated white paper on “Astrobiology and Solar System Exploration”.

Our efforts on several large-scale education outreach efforts came to fruition this year:

  • The last of nine permanent wayside exhibits featuring astrobiology themes were emplaced in Yellowstone National Park. This completes the second of a three-phase effort that also includes publishing a new chapter in the Yellowstone Resources and Issues Manual and designing a microbiology/astrobiology section for the new Old Faithful Visitor Education Center.
  • A new astrobiology-themed exhibit, “Xtreme Life” was opened at the California Academy of Sciences. The exhibit, for which every phase of design and review involved ARC team members, will be viewed by potentially hundreds of thousands of visitors during its two-year run. The project now enters an initial design phase for a permanent astrobiology exhibit for the newly-remodeled CAS facility, to open in 2008.
  • An intensive, week-long, astrobiology-themed workshop (“Life at the Limits: Earth, Mars and Beyond”) was held as part of an annual series for high school and middle school science teachers. The workshop, organized by the Lunar and Planetary Institute, seeks to enrich the teaching of science at the secondary school level by exposing teachers to a combination of astrobiology-related field and classroom experiences. Via the impact on teaching, these workshops have a potential outreach to thousands of secondary school students.
  • Team members were actively involved in the past year’s Jason Project, “Mysteries of Earth and Mars”, which prominently featured our work with hypersaline microbial mats as an analog activity.